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Background: To evaluate the function of the abductor mechanism after a gluteus maximus flap transfer due to a degeneration of the muscles after hip arthroplasty, we analyzed the post-operative functional outcome as well as radiographic effects in muscle tissue. Methods: This present study included six consecutive patients operatively treated with a gluteus maximus flap due to chronic gluteal deficiency after total hip arthroplasty. All patients presented a preoperative severe limp, hip abductor deficiency and a history of conservative treatment without the relief of symptoms. MRI scans were performed pre- and postoperatively to evaluate the muscle volume and grade of degeneration of the abductor mechanism. For clinical evaluation, the Harris hip score (HHS) was applied pre- and postoperatively. Moreover, the intensity of pain, the Trendelenburg sign, the internal rotation lag sign and the abductor muscle force were measured before and after surgery. Results: Overall, the evaluation of the Magnetic Resonance Imaging (MRI) showed no significant changes in total muscle volume during the follow-up period. Separate measurements presented a significant growth of muscle volume for the gluteus minimus and tensor fascia lata compared to preoperative imaging during the follow-up period. The amount of fat volume decreased for all the measured muscles with statistical significance for the gluteus minimus, the gluteus medius and the tensor fascia lata. No further muscle degeneration and no flap necrosis were measured. The postoperative HHS results were not statistically significant compared to the preoperative results. Conclusions: Besides fair clinical results, the radiological measurements indicate that the flap transfer enables functional muscular tissue recovery and prevents further degeneration. Given these conditions, the gluteus maximus muscle flap transfer represents a viable treatment option for patients with chronic gluteal deficiency in selected patients. [ABSTRACT FROM AUTHOR]

Background: Conflicting evidence exists regarding outcomes in middle-aged patients undergoing periacetabular osteotomy (PAO) for symptomatic developmental dysplasia of the hip (DDH). Aims: To compare patient reported outcomes (PROMs) of middle-aged PAO patients with younger patient groups. Methods: Retrospective analysis of prospectively collected data of PAO patients between 01/2015 and 06/2017 at a single orthopedic university center with a primary diagnosis of symptomatic DDH. The cohort was divided into four age groups and compared: < 20, 20–30, 30–40 and > 40 years. Joint function was assessed using iHOT-12, mHHS and SHV. Activity level was assessed using UCLA Activity score. Patient satisfaction and pain were assessed on the numerical rating scale 0–10. Conversion rates to THA were assessed. Results: Out of 202 PAOs, 120 cases with complete data were included. Mean follow-up was 63 months (range 47–81 months). Eighteen patients were < 20 years old, 54 were 20–30 years, 37 were 30–40 years, 11 patients were older than 40. No significant differences were observed for preoperative or postoperative iHOT-12 (p = 0.898; p = 0.087), mHHS (p = 0.878; p = 0.103), SHV (p = 0.602; p = 0.352) or UCLA (p = 0.539; p = 0.978) between groups. Improvement deltas were also not significantly different for all PROMs. Postoperative patient satisfaction was similar between groups (p = 0.783). Conclusion: Patients with symptomatic DDH may benefit from PAO even at middle age with similar outcomes and pre- to postoperative improvements as younger age groups. Indication should be based on biological age and preoperative joint condition rather than age. [ABSTRACT FROM AUTHOR]

Background and purpose: The study compares early outcomes after simultaneous and staged knee arthroplasty in patients with bilateral knee osteoarthritis (OA) to evaluate whether simultaneous bilateral TKA shows comparable early outcomes and complication rates to staged bilateral TKA. Methods: A retrospective cohort study including all patients scheduled for primary TKA for bilateral knee OA (n = 127) was conducted. Patients received either simultaneous (n = 53, 41.7%) or staged (n = 74, 58.3%) bilateral TKA by a single, high-volume surgeon—depending on their individual preference. Demographic data, haemoglobin drop (Hb), length of stay (LOS), operation time, 30-day complication rate and achievement of rehabilitation key points were evaluated. Results: There was no difference between the groups concerning age, sex, BMI or complication rate. ASA scoring was better in the simultaneous group [2.2, (15.1% ASA 1, 49.1% ASA 2, 35.8% ASA 3) vs. 2.4 (2.7% ASA 1, 51.4% ASA 2, 45.9% ASA 3)]. Average LOS was 7.8 ± 2.1 days for simultaneous TKA, 7.4 ± 1.7 days for single procedure of staged group (p < 0.453) and 14.7 ± 3.1 days if combined (p < 0.001). Cumulative Hb loss was significantly higher in the staged group (3.8 ± 1.2 g/dl vs. 2.4 ± 0.8 g/dl, p < 0.001). Detailed comparison of early outcome parameters between staged and simultaneous procedure depending on ASA score only revealed slightly slower assessment of stairs (p < 0.001) and increased Hb drop per surgery in case of simultaneous procedure (p < 0.011) if ASA score was ≥ 2. Only patients scored ASA 3 demonstrated a significant longer LOS per procedure in simultaneous group (8.5 ± 2.4 vs.7.3 ± 1.6 days, p = 0.034). Interpretation: Simultaneous bilateral TKA results in comparable early outcome and complication rate than staged bilateral procedure—even for patients scored ASA 3. Level of evidence: Level IV. [ABSTRACT FROM AUTHOR]

Background: The impact of the prior fixation mode on the treatment outcome of chronic periprosthetic joint infection (PJI) of the hip is unclear. Removal of cemented total hip arthroplasty (THA) is particularly challenging and residual cement might be associated with reinfection. This study seeks to compare the results of two-stage revision for PJI in cemented and cementless THA. Methods: We reviewed 143 consecutive patients undergoing two-stage revision THA for PJI between 2013 and 2018. Thirty-six patients with a fully cemented (n = 6), hybrid femur (n = 26) or hybrid acetabulum (n = 4) THA (cemented group) were matched 1:2 with a cohort of 72 patients who underwent removal of a cementless THA (cementless group). Groups were matched by sex, age, number of prior surgeries and history of infection treatment. Outcomes included microbiological results, interim re-debridement, reinfection, all-cause revision, and modified Harris hip scores (mHHS). Minimum follow-up was 2 years. Results: Compared with PJI in cementless THA, patients undergoing removal of cemented THA had increasingly severe femoral bone loss (p = 0.004). Patients in the cemented group had an increased risk for positive cultures during second-stage reimplantation (22% compared to 8%, p = 0.043), higher rates of reinfection (22% compared to 7%, p = 0.021) and all-cause revision (31% compared to 14%, p = 0.039) compared to patients undergoing two-stage revision of cementless THA. Periprosthetic femoral fractures were more frequent in the group of patients with prior cementation (p =.004). Mean mHHS had been 37.5 in the cemented group and 39.1 in the cementless group, and these scores improved significantly in both groups (p < 0.01). Conclusion: This study shows that chronic infection in cemented THA might be associated with increased bone loss, higher rates of reinfection and all-cause revision following two-stage revision. This should be useful to clinicians counselling patients with hip PJI and can guide treatment and estimated outcomes. [ABSTRACT FROM AUTHOR]

Background: A preoperative pathogen detection is considered a prerequisite before undergoing one-stage exchange for prosthetic joint infection (PJI) according to most guidelines. This study compares patients with and without preoperative pathogen detection undergoing one-stage exchange for PJI of the hip. The authors put up the hypothesis that a preoperative pathogen detection is no prerequisite in selected cases undergoing one-stage exchange. Methods: 30 consecutive patients with PJI of the hip, treated with one-stage exchange, between 2011 and 2021, were retrospectively included. Mean age was 70 years and mean follow-up 2.1 ± 1.8 years. PJI was defined according to the European Bone and Joint Infection Society. One-stage exchange was performed in (1) chronic PJI longer than 4 weeks, (2) well-retained bone condition, (3) absence of multiple prior revisions for PJI (≤ 2) with absence of difficult-to-treat pathogens in the past, and (4) necessity/preference for early mobility due to comorbidities/age. Results: One-stage exchange was performed in 20 patients with and in 10 without a preoperative pathogen detection. Age (71 years, 68 years, p = 0.519), sex (50% and 30% males, p = 0.440), American Society of Anesthesiologists Score (2.2, 2.4, p = 0.502), and Charlson Comorbidity Index (3, 4, p = 0.530) did not differ among the two groups. No significant differences were noted concerning preoperative CRP (15 mg/l, 43 mg/l, p = 0.228), synovial cell count (15.990/nl, 5.308/nl, p = 0.887), radiological signs of loosening (55%, 50%, p = 0.999), and intraoperative histopathology. Except a higher rate of coagulase-negative staphylococci (70%, 20%, p = 0.019) in patients with a preoperative pathogen detection, no significant differences in pathogen spectrum were identified among groups. Revision for PJI recurrence was performed in one patient with an initial preoperative pathogen detection (3.3%). Additional revisions were performed for dislocation in two and postoperative hematoma in one patient. Revision rate for both septic and aseptic causes (p = 0.999), stay in hospital (16 and 15 days, p = 0.373) and modified Harris Hip Score (60, 71, p = 0.350) did not differ between groups. Conclusion: Patients with and without a preoperative pathogen detection did not show significant differences concerning baseline characteristics, clinical and functional outcomes at 2 years. An absent preoperative pathogen detection is no absolute contraindication for one-stage exchange in chronic PJI, if involving good bone quality and absence of multiple prior revisions. [ABSTRACT FROM AUTHOR]

Introduction: A devastating complication after total hip arthroplasty (THA) is chronic periprosthetic joint infection (PJI). Most frequently spacers (Sp) with or without antibiotics are implanted in a two-stage procedure even though not always indicated due to unknown pathogen, femoral and acetabular defects or muscular insufficiency. Materials and methods: A retrospective analysis of a prospectively collected database was conducted, analyzing the treatment of 44 consecutive cases with chronic PJI undergoing two-stage revision using a Girdlestone situation (GS) in the interim period between 01/2015 and 12/2018. Diagnostics included intraoperative microbiological cultures, histological analysis, sonication of the initial implant, analysis of hip aspiration, as well as laboratory diagnostics and blood cultures. We analyzed the general and age-group-specific success rate of treatment using GS. Furthermore, we compared our data with the current literature on spacer implantation regarding common complications. Results: In total, 21 female and 23 male patients at a mean age of 59.3 ± 9.6 years were included. Age groups were divided into young, mid-age, and elderly. In most patients, microbiology revealed Staphylococcus epidermidis in 39.1% of cases, following Staphylococcus lugdunensis and Staphylococcus aureus in 10.9% after THA explantation. For histology, Krenn and Morawietz type 2 (infectious type) was diagnosed in 40.9%, type 3 (infectious and abrade-induced type) in 25.0%. With GS, the total cure rate was 84.1% compared to 90.1% (range 61–100%) using Sp as described in the literature. Among age-groups, cure rate varied between 77.8 and 100%. Other complications, which only occurred in the mid-age and elderly group, included the necessity of transfusion in 31.1%, and in total, one periprosthetic fracture was identified (2.3%). Conclusion: GS shows an acceptable cure rate at a minimum of 2 years when compared to the cure rate reported in the literature for Sp without major complications. For patients with increased risks for treatment failure using spacer, GS seems to be an alternative for chronic PJI when looking at the success rate of treatment. Level of evidence: III, Retrospective trial. [ABSTRACT FROM AUTHOR]

Introduction: Periprosthetic joint infections (PJI) with osteosynthesis material for contemporaneous fractures are a challenging, yet poorly described condition. This study will analyze PJI with co-existing fractures treated with cerclages and two-stage exchange. Materials and methods: Patients with and without cerclages for coexisting periprosthetic fractures, undergoing two-stage exchange for PJI of hip or knee, between 06/2013 and 02/2016, were compared concerning baseline characteristics and re-infection rate in the course of a 2 year follow-up. All patients were treated with a standardized two-stage protocol. A PJI was defined according to the EBJIS criteria. All foreign material, including cerclages, was sent in for sonication for microbiological analysis. Results: Ninety-six patients treated with two-stage exchange for PJI could be included. Co-existing fractures treated with cerclage were identified in nine patients (9.3%, study group). Diaphyseal femoral simple in five cases (AO2A3) and proximal intertrochanteric in three cases (AO1A3) were the leading fracture locations. In one patient, cerclage implantation was performed prior to prosthesis explantation, in six, during prosthesis explantation, and in two, in the course of prosthesis reimplantation. The study group showed a significantly higher rate of difficult to treat microbes (44.4%; 8.0%; p =.001), Charlson Comorbidity Index (5.4; 3.7; p =.033), relapse infections with the same microbe (22.2%; 1.1%; p =.001), and early-onset infections (< 30 days) (11.1%; 1.1%; p =.046), than the comparison two-stage exchange group without fractures. In contrast, age (72.5 study group; 68.2 comparison group; p =.224), rate of revisions for PJI in the past (55.5%; 51.7%; p =.827), and total re-infection rate (22.2%; 10.3%; p =.287) did not show a difference. Conclusion: PJI with co-existing cerclages for fractures were associated with multi-resistant microbes, relapse by the same microbe and early-onset re-infections. Cerclages might be considered a potential source of re-infection during a two-stage exchange. However, statistical weaknesses and a small study group must be considered limitations of the study. [ABSTRACT FROM AUTHOR]

Introduction: Early diagnosis of periprosthetic hip and knee infection still represents a major challenge, as no single test can achieve ideal results. Currently, multiple preoperative indicators were performed to diagnose periprosthetic joint infection (PJI) to confirm or exclude infection in the early stage. However, the diagnostic value of biopsy-related tests in diagnosing periprosthetic hip and knee infection remains unclear. Materials and methods: Publications in PubMed, Embase, and the Web of Science databases were searched systematically until October 2020. Inclusion and exclusion criteria were used for screening biopsy-related studies of the diagnosis of periprosthetic hip and knee infection. Results: Three biopsy-related tests were identified in 14 articles and further analyzed in the present meta-analysis. The combined method had the highest value for the area under the curve (0.9805), followed by histology (0.9425) and microbiological tests (0.9292). In the subgroup, statistical differences were identified in sensitivity and specificity for PJI diagnosis between the synovial fluid culture and biopsy culture group, as well as in the biopsy-related combined method and serum C-reactive protein. Conclusions: Biopsy culture does not appear to be advantageous compared to synovial fluid culture in the preoperative diagnosis of periprosthetic hip and knee infection. In contrast, combined biopsy microbial culture with histology analysis shows great potential in improving the preoperative diagnosis of PJI. The standard procedure of biopsy needs to be further explored. Further research is required to verify our results. [ABSTRACT FROM AUTHOR]

Introduction: Mechanical failure of total hip arthroplasties is a rare but devastating complication. With increasing numbers in primary arthroplasty implantation, revision surgeries are indicated more often. Therefore, understanding the mechanism and the location of failure is essential in determining proper treatment. Aim of this study was to identify mechanical failures of all total hip arthroplasties performed in a major academic center as well as the associated risk factors such as BMI and sports. Methods: A retrospective trial was conducted using our prospective arthroplasty database. Database was searched for all patients presenting with mechanical failures of total hip arthroplasty (THA) to the emergency department between 2011 and 2019. All medical charts and radiographs as well as surgical reports were analyzed to identify demographics, implant choice in addition to location of failure and subsequent treatment. Results: In total, 13 patients suffering from mechanical total hip implant failure were found. The femoral neck (conus) was broken in four patients, the stem in five cases, one broken inlay, two cup failures and one conus dislocation. The mean BMI was 31.42 ± 5.29 kg/m2 including five patients who have obesity class II. In all cases, revision surgeries were indicated. No structural causes or underlying risk factors such as repeated physical load (i.e. in sports) were identified. Conclusion: Implant failure does not seem to correlate with participation in sports or BMI. Catastrophic failure of implants is a technical challenge requiring special extraction instruments that can be difficult even for experienced surgeons. It should be noted that functional outcome is often worse for this group of patients after surgery than comparing against those revised for loosening. Level of evidence.: III, Retrospective Trial. [ABSTRACT FROM AUTHOR]

Introduction: Early results using injectable autologous chondrocyte implantation (ACI) for the treatment of full thickness acetabular cartilage defects have been promising. However, so far there is no information on radiological results after injectable ACI using spheroids. The purpose of this sturdy was to (1) investigate the quality of tissue repair on MRI and (2) investigate the correlation between the MRI results and clinical results at a minimum follow-up of 24 months after third generation ACI in full thickness acetabular cartilage defects. It was hypothesized that ACI shows good MRI results in patients with large full thickness acetabular cartilage defects 24 months after surgery. It was also hypothesized that there is a correlation between postoperative clinical and MRI morphological results at a minimum follow-up of 24 months. Study design: Retrospective case series. Materials and methods: Patients with ACI for full thickness acetabular cartilage defects > 2 cm2 were evaluated by preoperative and postoperative clinical scoring tools including the modified Harris Hip Score (mHHS), the International Hip Outcome Tool (iHOT-33), and the Subjective Hip Value (SHV) as well as a high resolution indirect arthro-MRI 24 months after surgery utilizing an identical imaging protocol for all patients. The magnetic resonance observation of cartilage repair tissue (MOCART) scoring system was used to classify the repair tissue on MRI. Demographic patient data was evaluated for influencing factors for pre- and postoperative clinical as well as radiological results. Results: Thirty six consecutive patients (5 women/31 men, average age 32.9 years) had undergone two stage ACI procedure. The average size of the cartilage defect was 5.0 (2–6) cm2. The average follow-up was 29.9 (24–42) months. Four patients were not available for the final follow-up (follow-up rate 89%). The postoperative average MOCART score was 82.2 (± 14.2). MOCART score showed medium correlation of the item defect fill and the postoperative mHHS (r = 0.384, p = 0.043). There was no correlation of the other items or the total score with postoperative results. The patients showed significant improvement in the outcome measurements between preoperative and postoperative in the mHHS, the iHOT-33, and the SHV. Conclusions: Despite the large acetabular cartilage defects included in this study, ACI showed good MRI results with complete defect fill in 87.5% after a minimum 24-month follow-up. Statistically significant correlation of MRI and clinical results could only be seen with the item defect fill. Further research with longer follow-up is needed to evaluate the long-term results of ACI in acetabular cartilage defects. [ABSTRACT FROM AUTHOR]

Aims: The aim of this study was to compare the fixation stability and complications in patients undergoing periacetabular osteotomy (PAO) with either K-wire or screw fixation. Patients and methods: We performed a retrospective study to analyze a consecutive series of patients who underwent PAO with either screw or K-wire fixation. Patients who were treated for acetabular retroversion or had previous surgery on the ipsilateral hip joint were excluded. 172 patients (191 hips: 99 K-wire/92 screw fixation) were included. The mean age at the time of PAO was 29.3 years (16–48) in the K-wire group and 27.3 (15–45) in the screw group and 83.9% were female. Clinical parameters including duration of surgery, minor complications (soft tissue irritation and implant migration) and major complications (implant failure and non-union) were evaluated. Radiological parameters including LCE, TA and FHEI were measured preoperatively, postoperatively and at 3-months follow-up. Results: Duration of surgery was significantly reduced in the K-wire group with 88.2 min (53–202) compared to the screw group with 119.7 min (50–261) (p < 0.001). Soft tissue irritation occurred significantly more often in the K-wire group (72/99) than in the screw group (36/92) (p < 0.001). No group showed significantly more implant migration than the other. No major complications were observed in either group. Postoperative LCE, TA and FHEI were improved significantly in both groups for all parameters (p = < 0.0001). There was no significant difference for initial or final correction for the respective parameters between the two groups. Furthermore, no significant difference in loss of correction was observed between the two groups for the respective parameters. Conclusion: K-wire fixation is a viable and safe option for fragment fixation in PAO with similar stability and complication rates as screw fixation. An advantage of the method is the significantly reduced operative time. A disadvantage is the significantly higher rate of implant-associated soft tissue irritation, necessitating implant removal. Level of evidence: III, retrospective trial. [ABSTRACT FROM AUTHOR]

Introduction: The optimal treatment of patients with a degenerative joint disease secondary to an active or chronic septic arthritis of the hip is unclear. The aim of the present study was to report on our experience with two-stage total hip arthroplasty (THA) using a contemporary treatment protocol without spacer insertion. Materials and methods: Our prospective institutional database was used to identify all patients with degenerative septic arthritis treated with a non-spacer two-stage protocol between 2011 and 2017. Clinical outcomes included interim revision, periprosthetic infection (PJI) and aseptic revision rates. Restoration of leg-length and offset were assessed radiographically. Modified Harris hip score (mHHS) were obtained. Treatment success was defined using the modified Delphi consensus criteria. Mean follow-up was 62 months (13–110). Results: A total of 33 patients with a mean age of 60 years (13–85) were included. 55% of the cohort was male and average Charlson Comorbidity Index (CCI) was 3.7 (0–12). 21 patients (64%) had an active/acute infection and 12 patients (36%) were treated for chronic/quiescent septic arthritis. Overall, 11 patients (33%) had treatment failure, including 5 patients who failed to undergo THA, 2 interim re-debridement for persistent infection, and 4 patients who developed PJI after an average of 7 months (0.3–13) following THA. The most common identified pathogen was Staphylococcus aureus (42.4%). No aseptic revision was recorded following THA. Leg-length and offset were successfully restored. Mean mHHS improved from 35.2 points to 73.4 points. Conclusion: Two-stage THA without spacer placement is a viable treatment option for destructive septic arthritis of the hip, demonstrating comparable rates of infection control and functional outcome. However, definitive resection arthroplasty is not uncommon in these often critically ill patients. [ABSTRACT FROM AUTHOR]

Introduction: The patient's perspective plays a key role in judging the effect of knee disorders on physical function. We have introduced the Subjective Knee Value (SKV) to simplify the evaluation of individual's knee function by providing one simple question. The purpose of this prospective study was to validate the SKV with accepted multiple-item knee surveys across patients with orthopaedic knee disorders. Materials and methods: Between January through March 2020, consecutive patients (n = 160; mean age 51 ± 18 years, range from 18 to 85 years, 54% women) attending the outpatient clinic for knee complaints caused by osteoarthritis (n = 69), meniscal lesion (n = 45), tear of the anterior cruciate ligament (n = 23) and focal chondral defect (n = 23) were invited to complete a knee-specific survey including the SKV along with the Knee Injury Osteoarthritis Outcome Score (KOOS) and the International Knee Documentation Committee subjective knee form (IKDC-S). The Pearson correlation coefficient was used to evaluate external validity between the SKV and each patient-reported outcome measure (PROM) separately. Furthermore, patient's compliance was assessed by comparing responding rates. Results: Overall, the SKV highly correlated with both the KOOS (R = 0.758, p < 0.05) and the IKDC-S (R = 0.802, p < 0.05). This was also demonstrated across all investigated diagnosis- and demographic-specific (gender, age) subgroups (range 0.509–0.936). No relevant floor/ceiling effects were noticed. The responding rate for the SKV (96%) was significantly higher when compared with those for the KOOS (81%) and the IKDC-S (83%) (p < 0.05). Conclusion: At baseline, the SKV exhibits acceptable validity across all investigated knee-specific PROMs in a broad patient population with a wide array of knee disorders. The simplified survey format without compromising the precision to evaluate individual's knee function justifies implementation in daily clinical practice. Level of evidence: II, cohort study (diagnosis). [ABSTRACT FROM AUTHOR]

Introduction: New app-based programs for postoperative rehabilitation have been developed, but no long-term study has been published to date. Thus, a prospective randomized control trial with 2-year follow-up was performed to evaluate the effectiveness of app-based rehabilitation (GenuSport) compared to a control group after total knee arthroplasty (TKA). Methods: Between April and October 2016, 60 patients were enrolled in the study. Twenty-five patients were lost to follow-up, leaving 35 patients undergoing TKA for inclusion. In this group, twenty patients received app-based exercise program and 15 were randomized to the control group. The mean age was 64.37 ± 9.32 years with a mean follow-up of 23.51 ± 1.63 months. Patients in the app group underwent an app-based knee training starting on the day of surgery; whereas, patients in the control group underwent regular physiotherapy. Functional outcome scores using the Knee Injury and Osteoarthritis Outcome Score (KOOS), Knee Society Score (KSS) and VAS of pain were analyzed. Results: In the short term, significant differences between the app group and control group in time of 10-m walk (19.66 ± 7.80 vs. 27.08 ± 15.46 s; p = 0.029), VAS pain at rest and activity (2.65 ± 0.82 vs. 3.57 ± 1.58, respectively 4.03 ± 1.26 vs. 5.05 ± 1.21; p < 0.05) were observed. In the long term, a variety of different tendencies was found, highest in KSS Function with 76.32 ± 16.49 (app group) vs. 67.67 ± 16.57 (control group) (p = 0.130). Additionally, patients in the app group required less painkillers (10.0% vs. 26.7%) and more likely to participate in sports (65.0% vs. 53.3%). Conclusions: An app-based knee trainer is a promising tool in improving functional outcomes such as KSS function score and VAS after TKA. Level of evidence: Level II, prospective randomized control trial. [ABSTRACT FROM AUTHOR]

Purpose: Several studies describe risk factors for primary periprosthetic joint infection (PJI) and general treatment outcome factors like microbe spectrum or patient-specific risk factors. However, these general and patient dependent findings cannot solely explain all cases of infection persistence after a prior septic revision. This study analyzes possible specific and patient independent reasons for failure after revisions for PJI in knee and hip arthroplasty. Methods: In a prospective analysis all patients were included that were treated: (1) at our department, (2) with a two-stage exchange, (3) between 2013 and 2017, (4) due to an infection persistence after a previous revision for PJI. Possible reasons for infection persistence were identified using a checklist algorithm, based on international guidelines. Results: 70 patients with infection persistence could be included (44 knee joints, 26 hip joints). The average age was 71 years, the CCI (Charlson Comorbidity Index) 2.8 and the ASA (American Society of Anesthesiologists) score 2.7. In 85% at least one possible reason for patient independent infection persistence could be identified analyzing the previous infection therapy: (1) 50% inadequate therapy concept (n = 35), (2) 33% inadequate surgical debridement (n = 23), (3) 30% inadequate antimicrobial therapy (n = 21), (4) 13% missed external bacterial primary focus (n = 9). After the individual failure analysis, all 70 patients were treated with a two-stage exchange in our department and in 94.9% infection freedom could be achieved (34.3 ± 10.9 months follow-up). Conclusions: In the majority of failed revisions with subsequent infection persistence at least one possible patient independent failure cause could be identified. The entire previous therapy should be critically reviewed following failing revisions to optimize the outcome of septic revisions. By using a checklist algorithm, high rates of infection freedom were achieved. [ABSTRACT FROM AUTHOR]

Background: Precise measurement of the tibial slope (TS) is crucial for realignment surgery, ligament reconstruction, and arthroplasty. However, there is little consensus on the ideal assessment. It was hypothesized that the tibial slope changes according to the acquisition technique and both tibial length as well as femoral rotation serve as potential confounders.Methods: 104 patients (37 women, 67 men; range 12-66 years) were retrospectively selected, of which all patients underwent a 1.5-Tesla MRI and either additional standard lateral radiographs (SLR, n = 52) or posterior stress radiographs (PSR, n = 52) of the index knee. Two blinded observers evaluated the medial tibial slope as the medial TS is primarily used in clinical practice. Additionally, the length of the diaphyseal axis and the extent of radiographic malrotation were measured.Results: Mean TS on MRI was significantly lower compared to radiographs (4.2° ± 2.9° vs. 9.1° ± 3.6°; p < 0.0001). There was a significant correlation between MRI and PSR (p < 0.0001 with r = 0.7), but not with SLR (p = 0.93 with r = 0.24). Tibial length was a significant predictor for the difference between MRI and SLR (regression coefficient ß = - 0.03; p = 0.035), yet not between MRI and PSR (ß = - 0.003; p = 0.9). Femoral rotation proved to be a significant predictor for the agreement between both observers (PSR: ß = 0.14; p = 0.001 and SLR: ß = 0.08; p = 0.04). ICC indicated a high interrater agreement for the radiographic assessment (ICC ≥ 0.72).Conclusions: There is a substantial variance between MRI and radiographic measurement of the tibial slope. However, as MRI assessment is time-consuming and requires specialized software, instrumented radiographs might be an alternative. Due care has to be taken to ensure that radiographs contain a sufficient tibial length, and femoral rotation is avoided.Study Design: Case series (diagnosis); Level of evidence, 4. [ABSTRACT FROM AUTHOR]

Background: The simultaneous occurrence of periprosthetic fracture (PPF) and periprosthetic joint infection (PJI) is among the most devastating complications in arthroplasty and carries the risk of limb loss. For the first time, this study will describe the characteristics, treatment concepts, and outcomes of this complication.Methods: Patients were consecutively included who were treated at our specialized interdisciplinary department between 2015 and 2016 with a PJI and an additional PPF of the hip. The treatment algorithm followed a three-step procedure: the complete removal of any foreign material (step 1), fracture stabilization by plate, intramedullary rod osteosynthesis or cerclages using an additional spacer (step 2), and reimplantation of a new prosthesis (step 3).Results: Overall, eight cases [four male, four female, mean age 77 years (55-91)] were included. The mean follow-up was 34 ± 8 months. The fractures included one PPF Vancouver B1, three B2/3, and four type C. Most frequent microbes were CNS (Coagulase-negative staphylococci) (n = 4), Cutibacterium (n = 2) and Staphylococcus aureus (n = 2). Mixed infections (≥ 2 microorganisms) occurred in five cases. The time between explanation and reimplantation was 42 ± 34 (range 7-123) days. A re-infection took place in one, a re-revision in four cases, and in five cases fracture healing was noticed. In all eight cases, freedom from the infection and limb preservation could be achieved.Conclusion: PPF in the case of a PJI is a devastating situation and a huge challenge. Extremity preservation should be the primary goal. The described procedure offers a possible solution. [ABSTRACT FROM AUTHOR]

Introduction: A two-stage exchange is the standard treatment approach for chronic periprosthetic joint infection (PJI). While a 6-8 week interval is commonly used before reimplantation, the optimal length of the prosthesis-free interval has not yet been determined. We evaluated the influence of a short (< 4 weeks) and long (≥ 4 weeks) interval on reinfection rate and functional outcome of hip and knee PJI.Methods: In this prospective cohort, patients undergoing two-stage revision for PJI were assigned to prosthesis reimplantation after a short (< 4 weeks) or long (≥ 4 weeks) interval. All patients received standardized antimicrobial therapy, which consisted of antibiogram-adapted, non-biofilm-active antibiotics during the interval and an antimicrobial combination therapy with biofilm-active antibiotics after reimplantation. Follow-up was performed for infection, joint function, pain, need for care and quality of life.Results: Thirty-eight patients undergoing two-stage revision for PJI (18 hips and 20 knees) were included. Short interval was used in 19 patients having a mean interval of 17.9 days (range 7-27 days), long interval in 19 patients having a mean interval of 63.0 days (range 28-204 days). At a mean follow-up of 39.5 months (range 32-48 months), 37 of 38 patients (97.4%) were infection-free. One failure occurred among patients with long interval and none among patients with short interval. Functional results (ROM, HHS, KSS, VAS) and quality of life (SF-36) were similar in both groups. Patients treated with long interval required cumulatively additional 204 inpatient days for nursing care compared to patients with short interval.Conclusions: This study suggests that two-stage exchange with short interval has a similar outcome than with long interval, when highly active antibiotic therapy is used. Patient inconvenience and care costs due to immobilization were lower when strategies with a short interval were used. [ABSTRACT FROM AUTHOR]

Introduction: Reverse shoulder arthroplasty shifts the rotational center of the shoulder joint caudally and medially to restore shoulder function in a rotator cuff deficient shoulder. Despite promising results in early- and mid-term follow-up, long-term loss in shoulder function has been described in the literature. A lack of exercise in elderly patients may be one reason for this loss in function. This study examines the functional benefits of physical therapy in the mid-term to long-term follow-up regarding the subjective and objective shoulder function.Materials and Methods: Twenty patients with a mean age of 73 years were included in this series. The study was performed as a single-center, prospective study. Initial indications for reverse shoulder arthroplasty were cuff tear arthropathy, failed anatomical shoulder arthroplasty, and fracture sequelae. The patients were clinically examined at a mean follow-up of 62 months using the Constant score (CS) and the DASH score for the operated and the non-operated shoulder. They were reevaluated using the same scores following a standardized physical therapy program of 6 weeks' duration.Results: The mean CS as well as the mean age- and gender-adjusted CS of the affected shoulder improved significantly from 53.5 to 59.3 points, and 72.7-80.8%, respectively. The subcategories activities of daily living (ADL) and range of motion (ROM) of the CS improved significantly, whereas no significant improvement was observed for the subcategories pain and strength. Evaluating the contralateral shoulder, no significant change was observed for the age- and gender-adjusted CS and the CS as well as its subcategories. We found no significant difference in the CS comparing the different etiologies prior to physical therapy.Discussion: Physical therapy plays an important role subsequent to reverse shoulder arthroplasty. It also has an effect in the mid-term to long-term follow-up regarding the range of motion as well as activities of daily living. However, physical therapy seems to have limited effect on the strength and the residual pain level.Level Of Evidence: Level III. [ABSTRACT FROM AUTHOR]

Introduction: Reinfection after two-stage exchange arthroplasty is a difficult clinical scenario with limited data on adequate treatment algorithms. Beside the possibility of treatment failure and a new intraoperative infection at the time of reimplantation, hematogenous seeding could play an up to date underestimated crucial role as another cause of an infection after two-stage exchange. The aim of this study was to evaluate its incidence and treatment possibilities in a prospectively followed case series.Methods: All consecutive hip and knee periprosthetic joint infection cases (93 hips and 89 knees) treated according to a standardized diagnostic and therapeutic algorithm at our institution with a two-stage exchange arthroplasty from 2013 to 2015 were included and followed prospectively to identify recurrent infections due to hematogenous seeding.Results: Six percent from our septic revision hip and knee arthroplasties (11 of 182, including 5 hips and 6 knees) were identified with a hematogenous reinfection after a mean follow-up of 31.8 months (range 14-48 months). The mean time to reinfection after reimplantation was 12.2 months (range 3.1-35.1). In all but two cases was the causative microorganism different than isolated at the time of initial two-stage exchange. In 5 of 11 patients, the primary focus of infection was identified.Conclusion: Hematogenous infection after a successful two-stage exchange arthroplasty is a rare but very important cause of a reinfection. With our work, we aim at raising the awareness for this entity and recommend consideration of irrigation and debridement with implant retention in these cases, as well as possibly the identification of a primary infection source. [ABSTRACT FROM AUTHOR]

Introduction: Osteochondral defects of the knee may cause functional impairment of young and sportively active patients. Different surgical treatment options have been proposed using either one or two step procedures. The aim of the current study was to evaluate mid-term outcomes of combined bone grafting with autologous matrix-associated chondrogenesis (AMIC) for the treatment of large osteochondral defects.Materials and Methods: 15 Patients with osteochondrosis dissecans of the medial femoral condyle grade III or IV according to ICRS classification were treated with a single step surgical procedure combining bone grafting and the AMIC procedure. Mean defect size was 4.98 cm2 (± 3.02) and patients were examined at 6, 12 weeks, 6 and 12 month and at mean final follow-up of 49 months (36-61). Patients were evaluated using VAS, IKDC, KOOS, Lysholm, Tegner activity scores and psychological and physical health assessed using the SF 12. MRI evaluation was performed at final follow-up using the MOCART score.Results: Pain had significantly decreased at final follow-up (7.2 ± 1.4 vs. 2.4 ± 2.6) compared to preoperative baseline. All functional scores had improved significantly throughout the follow-up period (IKDC from 36.6 ± 20.6 vs. 72.2 ± 18.7; KOOS 50.0 ± 18.9 vs. 81.7 ± 13.9; LYSHOLM 39.3 ± 19.5 vs. 79.8 ± 15.1). SF12 evaluation showed a significant increase in physical component summary (PCS) (31.2 ± 11.1 preoperative vs. 46.3 ± 9.9 at final follow-up), while mental component summary (MCS) remained stable (51.8 ± 8.9 vs. 57.3 ± 3.3). MOCART score revealed a mean overall score of 77 ± 15 at final follow-up. Integration to the adjacent cartilage was complete in 79%, incomplete in 21%. Defect filling was complete in 64%, incomplete in 36%.Conclusion: Significant improvement of knee function and restoration of homogenous cartilage morphology could be achieved with simultaneous AMIC procedure and bone grafting in 2/3 of all patients with large osteochondral lesions at 4 years postoperatively. [ABSTRACT FROM AUTHOR]

Background: Periprosthetic joint infections (PJI) caused by pathogens, for which no biofilm-active antibiotics are available, are often referred to as difficult-to-treat (DTT). However, it is unclear whether the outcome of DTT PJI is worse than those of non-DTT PJI. We evaluated the outcome of DTT and non-DTT PJI in a prospective cohort treated with a two-stage exchange according to a standardized algorithm.Methods: Patients with hip and knee PJI from 2013 to 2015 were prospectively included and followed up for ≥ 2 years. DTT PJI was defined as growth of microorganism(s) resistant to all available biofilm-active antibiotics. The Kaplan-Meier survival analysis was used to compare the probability of infection-free survival between DTT and non-DTT PJI and the 95% confidence interval (95% CI) was calculated.Results: Among 163 PJI, 30 (18.4%) were classified as DTT and 133 (81.6%) as non-DTT. At a mean follow-up of 33 months (range 24-48 months), the overall treatment success was 82.8%. The infection-free survival rate at 2 years was 80% (95% CI 61-90%) for DTT PJI and 84% (95% CI 76-89%) for non-DTT PJI (p = 0.61). The following mean values were longer in DTT PJI than in non-DTT PJI: hospital stay (45 vs. 28 days; p < 0.001), prosthesis-free interval (89 vs. 58 days; p < 0.001) and duration of antimicrobial treatment (151 vs. 117 days; p = 0.003).Conclusions: The outcome of DTT and non-DTT PJI was similar (80-84%), however, at the cost of longer hospital stay, longer prosthesis-free interval and longer antimicrobial treatment. It remains unclear whether patients undergoing two-stage exchange with a long interval need biofilm-active antibiotics. Further studies need to evaluate the outcome in patients treated with biofilm-active antibiotics undergoing short vs. long interval. [ABSTRACT FROM AUTHOR]

Introduction: Pigmented villonodular synovitis (PVNS) is a rare, destructive synovial disease that affects the hip joint the second most common after the knee. However, in contrast, joint preserving surgery in the hip joint is considered to be significantly more difficult or even impossible due to earlier occurrence of osteochondral dissemination and surgical difficulties. Today, earlier diagnosis due to the generous use of MRI and modern surgical strategies raise hope for improved outcomes.Methods: Since 2005, six patients with PVNS of the hip and a minimal follow-up of 2 years underwent joint preserving surgery in our institution (mean age 20.5 years, range 14-27). After PVNS was suspected in the MRI and confirmed by arthroscopic biopsy (four diffuse, two focal forms), synovectomy was carried out in 5 patients via surgical hip dislocation and in one focal case via arthroscopy. In diffuse forms, adjuvant radiosynoviorthesis (RSO) was conducted 6-8 week postoperatively. MRI and clinical examinations were performed during follow-up.Results: After a mean follow-up of 8 years (range 35-141 months), five of six patients did not show recurrence or secondary osteoarthritis. Clinical outcome evaluation resulted in a mean modified Harris Hip Score of 91 points (range 67-100 points). A 21-year-old patient with a diffuse form and advanced osteochondral involvement at the time of diagnosis was eventually treated by total hip arthroplasty.Conclusion: In cases without osteochondral involvement, recurrence-free long-term results without progression of joint degeneration can be achieved by joint preserving therapy. [ABSTRACT FROM AUTHOR]

Introduction: A hypertrophic AIIS has been identified as a cause for extraarticular hip impingement and is classified according to Hetsroni using 3D-CT reconstructions. The role of the conventional AP pelvis X-ray, which is the first standard imaging step for the evaluation of hip pain, has not been investigated yet.Materials and Methods: AP pelvis X-rays and 3D-CT reconstructions of patients were evaluated regarding their morphology of the AIIS. The conventional X-rays were categorized into three groups according to the projection of the AIIS: above (A) or below (B) the acetabular sourcil or even exceeding the anterior acetabular rim (C). They were compared to the morphologic types in the 3D-CT reconstruction (Hetsroni type I-III).Results: Ninety patients with an equal distribution of type A, B or C projection in the AP pelvis were evaluated and compared to the morphology in the 3D-CT reconstruction. The projection of the AIIS below the acetabular sourcil (B + C) showed only moderate sensitivity (0.76) and specificity (0.64) for a hypertrophic AIIS (Hetsroni type II + III), but if the AIIS exceeds the anterior rim, all cases showed a hypertrophic AIIS in the 3D-CT reconstructions (Hetsroni type II + III).Conclusions: Distinct differentiation of the AIIS morphology in the AP pelvis is not possible, but the projection of the AIIS below the anterior acetabular rim represented a hypertrophic AIIS in all cases and should, therefore, be critically investigated for a relevant AIIS impingement. [ABSTRACT FROM AUTHOR]

Introduction: Acetabular cartilage lesions are frequently seen in young patients with hip pain and have been identified as an important prognostic factor. New therapies have complemented abrasion and microfracture procedures. The aim of the study is to evaluate the early outcome of patients with arthroscopic injectable autologous chondrocyte transplantations (ACT) for full thickness acetabular cartilage defects.Methods: A two-step procedure ACT was performed in patients with full thickness acetabular cartilage defects measuring ≥2 cm(2). The patients were closely followed with clinical examination, pre- and postoperative scores until the latest available follow-up of 3, 6, 12, and 24 months.Results: 20 consecutive cases (4 female, 16 male, mean age 33 years) were included. No patients were lost at final follow-up. The average defect size was 5.05 (range 2-6) cm(2). The average follow-up was 12.05 (range 6-24) months. Three months postoperatively the preoperative scores improved significantly from a mean mHHS of 63-81 points (p = 0.009), iHOT33 of 44-66 % (p = 0.028) and subjective hip assessment (Subjective Hip Value, SHV) of 60-87 % (p = 0.007). After 12 months the results improved significantly to a mean mHHS of 93 points (p = 0.017), an iHOT33 of 79 % (p = 0.007) and an SHV of 82 % (p = 0.048) compared with the preoperative scores.Discussion: The injectable matrix associated ACT is a reliable procedure, yielding promising early results with a significant increase of all scores evaluated in patients with full thickness acetabular cartilage defects. [ABSTRACT FROM AUTHOR]

Purpose: Individual implant alignment in total knee arthroplasty (TKA) has seen growing interest over the past years. This study therefore aimed to develop a surgical technique for implant alignment based on native ligament tension, and to present the results obtained using this technique.Methods: 25 patients were included in this prospective study. Patient-specific instrumentation (PSI) was used for the resection of the extension gap. Ligament tension was measured after the removal of all accessible osteophytes. In the event of asymmetry, the distal femur resection was adjusted up to 2.5° using an adjustable cutting block. The aim was to achieve a symmetrical extension gap without release, not a neutral leg axis. Femoral rotation was aligned on the basis of ligament tension. Patients were followed up to 3 months postoperatively.Results: The postoperative whole-leg axis was 2.8° ± 1.6° varus. Patients achieved a flexion of 118° ± 9°, a Knee Score of 91.5 ± 3.2 and a Function Score of 86.8 ± 8.3 points.Conclusion: For the first time, the new surgical technique described here permits a ligament tension based femoral implant alignment together with PSI. It was shown to be safe, with encouraging clinical and radiological results.Level Of Evidence: Therapeutic study level IV. [ABSTRACT FROM AUTHOR]

Introduction: The concept of femoroacetabular impingement (FAI) and the indication for surgical intervention have been established in the last decade. Despite promising short-term results and emerging arthroscopic techniques, it remains unclear whether patients benefit from surgical correction in the mid- to long-term and whether progressive joint degeneration can be prevented. Materials and Methods: A retrospective study of our first 50 consecutive patients who underwent arthroscopic correction for FAI was conducted. The modified Harris hip score (mHHS) was assessed preoperatively and at final follow-up. In addition, the Western Ontario and McMaster Universities osteoarthritis index (WOMAC) and a subjective hip value (SHV) were added at final follow-up. Degenerative changes according to Kellgren and Lawrence scale and the α angle were analyzed preoperatively and on the most recent radiograph. Results: Of a total of 50 patients, 44 (24 male, 20 female) with a mean age of 34.3 years (17-65) were available with complete follow-up. Of these 44 patients, 39 were treated with correction of the femoral offset for isolated cam deformity, 5 with additional focal pincer correction and partial labral resection. After a mean follow-up of 66.3 ± 14.5 months the mHHS had improved significantly from 67.2 ± 6.4 preoperatively to 86.4 ± 13.5 (p < 0.001). The WOMAC score (converted to 0 = best/100 = worst) resulted in mean indices for the subcategories pain, stiffness and function of 11.8 ± 16.5, 12.2 ± 17.8 and 9.1 ± 16.1. The SHV was reported with a mean of 77.7 ± 21.8 % at final follow-up. The α angle was reduced significantly from 57.2° ± 10.1° to 46.3° ± 7.4° (p < 0.001). The Kellgren and Lawrence score showed a non-significant trend from 2.0 ± 0.8 preoperatively to 2.2 ± 0.9 in the most recent radiograph (p = 0.46). 5 patients had been converted to a total hip arthroplasty a mean of 28 ± 7.1 months postoperatively. These patients were significantly (p < 0.01) older with a mean age of 49.8 ± 7.8 years and showed significantly higher present osteoarthritic changes with an average Kellgren and Lawrence score of 2.6 ± 2.5 before FAI correction (p < 0.01). Conclusions: Arthroscopic correction of femoroacetabular impingement results in a persistent clinical improvement without significant progression of degenerative changes in the majority of patients. The indication for surgery should be established cautiously when degenerative changes are present. Level Of Evidence: Level IV, Case series with no comparison group. [ABSTRACT FROM AUTHOR]

Introduction: Combining patient-specific instrumentation (PSI) with a balancer device in total knee arthroplasty (TKA) to achieve functional femoral rotational alignment is a novel technique. The primary goal of this study was to introduce a new method to combine PSI with a gap-balancing technique and to determine the impact of the technique on rotation of the femoral component.Materials and Methods: Twenty-five primary TKAs (15 women, 10 men) were prospectively studied. All TKAs involved PSI with an associated gap-balancing device. Front plane alignment was performed intraoperatively with the PSI, followed by rectangular, symmetrical extension and creation of a flexion gap using the balancer device to set the femoral rotation.Results: Femoral component rotation was between 3° internal and 6° external rotation versus the transepicondylar axis. There were no postoperative signs of patellofemoral dysfunction. In no cases was the resulting joint line displacement >3 mm. The mean elevation was 1.2 ± 0.9 mm (range 0-3). The leg axis was straight in all cases (±3°), at a mean of 1.6° ± 1.0° varus (range 0°-3° varus).Conclusions: PSI was with the gap-balancing technique was successfully used without affecting anatomical alignment. With the balancer device, PSI can be used more widely than techniques based solely on landmarks, as the soft-tissue tension can be taken into account, thus virtually eliminating flexion instabilities. [ABSTRACT FROM AUTHOR]

Reverse shoulder arthroplasty (RSA) represents an established procedure for treatment of fracture sequelae (FS) after proximal humerus fractures. The present work evaluates which factors are of influence for the clinical outcome. Fifty cases (mean age 69, range 44-89) have been evaluated postoperatively clinically [Constant Score (CS)] and radiographically (mean FU 34; range 24-93 months). The type of primary treatment, the amount of a metaphyseal bone defect, the preoperative status of the rotator cuff, the number of previous operative interventions and the type of FS according to Boileau were analysed whether they are of influence for clinical outcome. The mean CS increased significantly from 16.9 ± 6.7 preoperatively to 54.1 ± 15.7 points postoperatively. The CS of primary conservative treatment was significantly higher in comparison to primary operative treatment. Patients with a metaphyseal bone defect of more than 3 cm had significantly lower CS results. Degenerative changes of the teres minor muscle also had a significant negative influence on clinical results. Score results decreased with increasing number of previous operations. There were no significant difference in between patients classified as Boileau type I and II (category 1) compared to types III and IV (category 2). RSA significantly improved the clinical result. A metaphyseal bone defect and preoperative degeneration of the teres minor showed to be negative prognostic factors. Primary operative treatment and the number of previous operations also negatively influenced the clinical result. [ABSTRACT FROM AUTHOR]

Introduction: There is still a relevant rate of outliers in coronal alignment >3° when the conventional technique is used, potentially accompanied by a poorer long-term clinical outcome and a reduced longevity of the implant. Intraoperative implementation of preoperative planning and above all checking of the bone resections carried out are decisive for reinstating a straight leg axis. Intramedullary control of femoral resection has not been described to date. The objective of this study was to present a new technique for the intramedullary control of femoral resection and the results obtained using this method. Methods: All patients who underwent primary total knee arthroplasty with the new intramedullary control of femoral resection were included in this retrospective study. The frequency of the need for correction of the saw cuts was documented. The radiological assessment included pre- and postoperative whole-leg standing radiographs. In the process, the whole-leg axis, AMA, entry point, LDFA and MPTA were evaluated preoperatively. On the postoperative radiographs, the whole-leg axis and the alignment of the femoral and tibial components were evaluated. Results: One hundred and sixty-two total knee arthroplasties (TKAs) were included in the study. The average age was 68.7 years. The preoperative malalignment was on the average 8.2° ± 4.7° (23.8° varus to 17.3° valgus). The postoperative whole-leg axis was on the average 1.3° ± 1.1° (5.5° varus to 4.3° valgus). The femoral component showed a deviation from the mechanical axis of 0.1° ± 1.2° (4.3° varus to 3.7° valgus) and the tibial component a deviation from the mechanical tibial axis of 0.3° ± 1.2° (4.2° varus to 2.5° valgus). Conclusions: The new technique of intramedullary control of distal femoral resection, together with preoperative planning, leads to a precise alignment of the femoral component in the coronal plane. Thus, for the first time, a simple and effective tool for checking distal femoral resection is available for standardized use. [ABSTRACT FROM AUTHOR]

Introduction: Minimally invasive total hip arthroplasty has been successfully introduced in the past decade. Nevertheless, standard approaches such as the direct lateral approach are still commonly used in orthopaedic surgery due to easy handling, good intra-operative overview and low complication rates. However, a frequent occurrence of fatty atrophy within the anterior third of the gluteus medius muscle has been demonstrated when using the modified direct-lateral approach (mDL), which may be associated with a reduction in function, limitation of internal leg rotation, gait disorders and pain. The question addressed in this study is whether mDL-approach leads to unfavourable changes in foot progression angle (FPA), gait and to more postoperative pain compared with a minimally invasive anterolateral approach (ALMI). Methods: Thirty patients with primary osteoarthritis of the hip were recruited for this study. All subjects received an uncemented THA (Alloclassic-Zweymüller stem, Allofit Cup, FA Zimmer), 15 through an ALMI-approach and 15 via the mDL-approach. Gait analyses were performed both preoperatively and 3 months after surgery to measure FPA, step length, stance duration, cadence and walking speed. Additionally, the Harris-Hip Score, pain according to the visual analogue scale and the Trendelenburg sign were evaluated. Results: No influence of the surgical approach could be observed on the gait patterns or FPA. Furthermore, neither increased external rotation of the limb nor restriction of internal rotation during walking could be established. Pain and Harris-Hip Score did not differ significantly between the two groups. Conclusion: In comparison with an ALMI approach, the mDL approach did not lead to a change in FPA postoperatively. No detrimental effect could be found on the gait pattern or pain after surgery. Based on these measurements, the minimally invasive anterolateral approach did not appear to provide functional benefits in outcome over the mDL approach. Consequently, both surgical approaches seem to be equally applicable approaches with good to very good functional results. [ABSTRACT FROM AUTHOR]

Introduction: This feasibility study investigated the accuracy of anterior pelvic reference plane (APP) registration and acetabular cup orientation in two cadavers with different BMIs. Method: Five observers each registered the APP five times in the 2 cadavers (BMIs: 32 kg/m² and 25 kg/m²) using an ultrasound-based navigation system. By comparison against the CT-derived reference landmarks, the errors in determining the individual landmarks defining the APP, as well as the resulting errors in the orientation of the APP and the acetabular cup orientation were determined. Results: Across all measurements obtained with the ultrasound navigation system, the errors in rotation and version in determining the APP were 0.5° ± 1.0° and −0.4° ± 2.0°, respectively. The cup abduction and anteversion errors determined from all measurements of the five investigators for both cadavers together were −0.1° ± 1.0° and −0.4° ± 2.7°, respectively. The data further demonstrated a high reproducibility of the measurements for the resulting cup adduction and anteversion angle. Conclusion: Our preliminary results confirm that ultrasound navigation is a highly accurate tool that allows a reproducible registration of the APP and thereby enables accurate and precise intraoperative determination of the acetabular cup orientation also in patients with increased BMI. [ABSTRACT FROM AUTHOR]

Introduction: Low-molecular-weight heparins (LMWH) are commonly used in thrombosis prophylaxis after total knee arthroplasty. In contrast to LMWH, dabigatran etexilate is an oral and direct acting anticoagulant. The hypothesis of the present study was that blood loss occurring in total knee arthroplasty (TKA) is not greater after dabigatran etexilate than after dalteparin. Method: All patients suffering from primary arthrosis of knee joint that had received a total knee arthroplasty were included in this retrospective case-control study. Two groups were formed (dalteparin versus dabigatran etexilate) and the perioperative blood loss was compared using the formula of Nadler ( V = EBV × ln (Hct/Hct) [V = blood loss (l); EBV = blood volume (l); Hct = preoperative haematocrit; Hct = haematocrit on the first postoperative day]. Patients: A total of 155 patients, 61 men and 94 women, were included. The calculated blood loss differed significantly between the two groups. The blood loss was on average 1.5 ± 0.58 l [0.32-2.9 l] in the dalteparin group, compared with 1.3 ± 0.63 l [0.29-4.31 l] in the dabigatran etexilate group ( p < 0.01). None of the patients of both observed groups showed clinical signs of thrombosis or pulmonary artery embolism. Results: Dabigatran etexilate showed a lower perioperative blood loss than dalteparin by comparable safety of both drugs. Conclusion: Whether the timing of administration or pharmacological factors were responsible for this cannot be explained by our study. [ABSTRACT FROM AUTHOR]

Introduction: In Europe the minimized transgluteal (TG) and anterolateral (AL) approaches are increasingly preferred in hip arthroplasty (THA). Method: The present investigation determined which of these approaches causes the least muscle trauma. Forty patients who received a THA were enrolled in this prospective randomized study. Muscle trauma was quantified by perioperatively measuring the serum concentration of skeletal troponin I (sTnI). The Harris hip score (HHS) was determined before and 12 months after surgery. Results: It increased significantly in all patients without being different between the groups (AL, 48.2→83.6; TG, 50.8→85.9). Patients in the TG group had a higher sTnI than those in the AL group 24 h postoperatively (21.6 vs. 10.9 nmol/ml, p = 0.022). The AL approach results in a reduced muscle traumatization compared with the TG approach, without this being revealed by the HHS. [ABSTRACT FROM AUTHOR]

Introduction: Minimally invasive total hip arthroplasty (THA) is claimed to be superior to the standard technique, due to the potential reduction of soft tissue damage via a smaller and tissue-sparing approach. As a result of the lack of objective evidence of fewer muscle and tendon defects, controversy still remains as to whether minimally invasive total hip arthroplasty truly minimizes muscle and tendon damage. Therefore, the objective was to compare the influence of the surgical approach on abductor muscle trauma and to analyze the relevance to postoperative pain and functional recovery. Materials and methods: Between June 2006 and July 2007, 44 patients with primary hip arthritis were prospectively included in the study protocol. Patients underwent cementless unilateral total hip arthroplasty either through a minimally invasive anterolateral approach (ALMI) ( n = 21) or a modified direct lateral approach (mDL) ( n = 16). Patients were evaluated clinically and underwent MR imaging preoperatively and at 3 and 12 months postoperatively. Clinical assessment contained clinical examination, performance of abduction test and the survey of a function score using the Harris Hip Score, a pain score using a numeric rating scale (NRS) of 0-10, as well as a satisfaction score using an NRS of 1-6. Additionally, myoglobin and creatine kinase were measured preoperatively, and 6, 24 and 96 h postoperatively. Evaluation of the MRI images included fatty atrophy (rating scale 0-4), tendon defects (present/absent) and bursal fluid collection of the abductor muscle. Results: Muscle and tendon damage occurred in both groups, but more lateral gluteus medius tendon defects [mDL 3/12mth.: 6 (37%)/4 (25%); ALMI: 3 (14%)/2 (9%)] and muscle atrophy in the anterior part of the gluteus medius [mean-standard (12): 1.75 ± 1.8; mean-MIS (12): 0.98 ± 1.1] were found in patients with the mDL approach. The clinical outcome was also poorer compared to the ALMI group. Significantly, more Trendelenburg's signs were evident and lower clinical scores were achieved in the mDL group. No differences in muscle and tendon damage were found for the gluteus minimus muscle. A higher serum myoglobin concentration was measured 6 and 24 h postoperatively in the mDL group (6 h: 403 ± 168 μg/l; 24 h: 304 ± 182 μg/l) compared to the ALMI group (6 h: 331 ± 143 μg/l; 24 h: 268 ± 145 μg/l). Conclusion: Abductor muscle and tendon damage occurred in both approaches, but the gluteus medius muscle can be spared more successfully via the minimally invasive approach and is accompanied by a better clinical outcome. Therefore, going through the intermuscular plane, without any detachment or dissection of muscle and tendons, truly minimizes perioperative soft tissue trauma. Furthermore, MRI emerges as an important imaging modality in the evaluation of muscle trauma in THA. [ABSTRACT FROM AUTHOR]

Introduction: In the analysis of painful total knee replacements, the surgical epicondylar axis (SEA) has become established as a standard in the diagnosis of femoral component rotation. It remains unclear whether the gap technique widely used to determine femoral rotation, when applied correctly, results in a rotation parallel to the SEA. Method: In this prospective study, 69 patients (69 joints) were included who received a navigated bicondylar surface replacement due to primary arthritis of the knee joint. Results: In 67 cases in which a perfect soft-tissue balancing of the extension gap (<1° asymmetry) was achieved, the flexion gap and the rotation of the femoral component necessary for its symmetry was determined and documented. The femoral component was implanted additionally taking into account the posterior condylar axis and the Whiteside's line. Postoperatively, the rotation of the femoral component to the SEA was determined and this was used to calculate the angle between a femur implanted according to the gap technique and the SEA. If the gap technique had been used consistently, it would have resulted in a deviation of the femoral components by −0.6° ± 2.9° (−7.4°-5.9°) from the SEA. The absolute deviation would have been 2.4° ± 1.8°, with a range between 0.2° and 7.4°. Conclusion: Even if the extension gap is perfectly balanced, the gap technique does not lead to a parallel alignment of the femoral component to the SEA. Since the clinical results of this technique are equivalent to those of the femur first technique in the literature, an evaluation of this deviation as a malalignment must be considered critically. [ABSTRACT FROM AUTHOR]

Background: Varus malalignment after total knee replacement is mentioned to be a major risk factor for postoperative pain and functional impairments. This wide spread opinion is based on the historical data derived from implantations performed in the late 1970s and early 1980s. We tested the hypothesis whether significant varus malalignment leads to minor functional results and early loosening using modern implants and operating techniques. Methods: Two hundred and eighteen knee joints (184 patients) having been replaced with a PFC Sigma or Natural Knee II with a minimum follow-up of 5 years were included in this case control study. From the 30 most varus malaligned knees (30 patients) 25 patients were available for clinical and radiographical examination (group A) and were compared with a control group without significant varus malalignment that was matched for sex, age and implant (group B). The Knee Society Score (KSS), the WOMAC and the SF36 were determined. Results: No implant showed radiological signs of loosening or had been revised. The deviation from the mechanical axis was 6.3° [3.9°-10.7° varus] in group A and 0° [2.6° valgus to 2.1° varus] in group B ( P < 0.001). The KSS was 158 [99-199] points in group A and 142 [78-198] points in group B (n.s.). The WOMAC did not reveal any significant differences between the groups either (group A 22 ± 27 points, group B 21 ± 21 points). Likewise in the SF36, neither in the sum nor in the individual scores was a significant difference found between groups A (56 ± 24 [8-90] points) and B (56 ± 18 [26-86] points). Conclusions: The present data do not support the assumption that there is a correlation between varus malalignment and a bad medium-term radiological and clinical outcome after total knee arthroplasty. This questions the indication for revision of painful and varus malaligned prostheses, since an improvement of the clinical outcome is not to be expected. [ABSTRACT FROM AUTHOR]

The influence of surgical trauma on gluteus minimus muscle in total hip arthroplasty (THA) and the impact on functional outcome has been hardly investigated up to now. Potential risks of minimus damage during the approach or femoral preparation is due to its attachment to the anterior facet of the greater trochanter. Possible trauma-associated functional deficits of minimus muscle may result in reduced abduction force or in an unstable hip joint. The aim of the present study was to assess the pre- and post-operative gluteus minimus muscle (tendon defects and fatty atrophy) in patient with anterolateral minimally invasive and modified lateral approach by means of magnetic resonance imaging (MRI) and to investigate the associated impact on functional outcome. Thirty-eight patients [average age, 64 years (35–80); BMI, 28 kg/m2 (19–35)] with primary coxarthrosis were prospectively enrolled in the study. A cementless hip prosthesis was implanted either via a minimally invasive anterolateral or a modified direct lateral approach. Patients were clinically and radiologically (MRI) examined preoperatively, 3, and 12 months postoperatively. Additionally, the Harris hip score, a pain score (NRS 0–10) and a satisfaction score (1–6) were recorded. To test the function of the abductor muscles the Trendelenburg’s sign and the abductor muscle strength were evaluated. MRI evaluation includes the assessment of tendon defects and fatty atrophy of the minimus muscle. Tendon defects and fatty atrophy were seen in nearly 50% of the patients after THA. Harris hip-, pain-, and satisfaction scores did not correlate with the MR findings. There was also no impact on the abduction strength or the Trendelenburg’s sign. Furthermore, the frequency of minimus damage was neither influenced by age, gender, BMI nor by the applied approach. Muscle atrophy and tendon defects of the minimus muscle appear frequently after THA without any favored relation to the lateral or anterolateral approach. The extent of injured minimus muscle has a minor impact on the clinical outcome particularly not on the abduction strength within the first postoperative year. The main function of the gluteus minimus is rather the centralization of the femoral head in the joint during the gait cycle than hip abduction and stabilization of the pelvis. The use of a straight stem with the associated need for lateral femoral preparation may be a risk factor for minimus tendon damage. Therefore, the surgeon should pay special attention to the prevention of surgical trauma to the gluteus minimus muscle during femoral preparation. [ABSTRACT FROM AUTHOR]

Despite a high complication rate, subjective and objective results of reversed shoulder arthroplasty for severe rotator cuff lesions associated with osteoarthritis, fracture sequelae, or revision of hemiarthroplasty are favorable. However, whether the changes in biomechanics of the joint may lead to structural changes in the remaining rotator cuff and the deltoid muscle, and may thereby alter the clinical result, has rarely been described. This study investigates the context between postoperative fatty infiltration of the remaining rotator cuff and the deltoid muscle, and the clinical outcome after reversed shoulder arthroplasty. Twenty-three patients with an average age of 73.1 ± 5.6 years were evaluated at an average of 26 ± 16.8 months. Evaluation included assessment of Constant Score, disabilities of the arm, shoulder and hand score, radiographic evaluation with measurement of the humeral lengthening and medialization of the center of rotation, and magnetic resonance imaging or computed tomography to classify changes in the rotator cuff and the deltoid muscle. There was a significant correlation between fatty infiltration of the deltoid muscle and the clinical score results. Patients with a longer follow-up showed a higher amount of degenerative changes of the deltoid than patients with a shorter follow-up. Degenerative changes of the rotator cuff showed no significant correlation to clinical results. The amount of arm lengthening, medialization of the center of rotation, and scapula notching showed no correlation to clinical results or degenerative changes of the deltoid and the rotator cuff. These data show that degeneration of the deltoid muscle is of impact for clinical outcome. Although other factors like disuse or pain as a reason for muscular changes cannot be fully excluded, this degeneration might occur after time due to biomechanical changes after reversed arthroplasty. However, prospective studies with longer follow-up periods and repetitive assessment of muscle quality are necessary to further support these results. [ABSTRACT FROM AUTHOR]

Two-stage revision hip surgery with insertion of local antibiotic carriers is the therapy of choice for infected hip arthroplasty. The disadvantages are the incalculable pharmacokinetics of the antibiotic, with the danger of resistance and sensitisation. In a retrospective study, the effectiveness of a two-stage revision strategy done without local antibiotics was to be investigated. Thirty-one patients (32 hips) after two-stage revision hip surgery for infection without local antibiotics were monitored clinically and radiologically, with a follow-up of 41.3 months. Nine re-debridements in combination with a systemic antibiosis had to be conducted for eradication of the infections after explantation. Reconstruction of the majority of the hips was possible without the use of revision implants and without using large structured allografts. The re-infection rate was 6.3%, the patients achieved a Harris hip score of 75.4 (range 36.1–97.0) points at the latest follow-up, and the average difference in leg length was −0.7 (range −4.5 to + 2.5) cm. Two-stage revision of the hip can be conducted without local antibiotic application, to achieve a comparatively efficient cure of the infection and function. This investigation underlines the significance of radical surgical debridement. The optional use of more effective antibiotic carriers may reduce the number of re-debridements in the future. [ABSTRACT FROM AUTHOR]

Background. It is difficult to identify objective parameters for assessing the joint function when dealing with the evaluation of orthopaedic procedures, especially endoprosthetic hip replacement. Clinical gait analysis enables parameters of force and movement to be quantified. However, the influence of gait speed on these parameters has hardly been taken into consideration so far. The objective of the present study was therefore to investigate the effect of gait speed on gait parameters and to simplify the clinical conditions in patients with osteoarthritis of the hip by determining a standardised gait speed. Methods. A total of 28 patients with severe unilateral osteoarthritis of the hip were investigated at different gait speeds. The gait analysis equipment used consisted of an infinitely adjustable treadmill with force plates and an infrared video system. A special control mechanism permitted adjustment of the treadmill speed to a patient's self-determined pace. Results. The mean gait speed of all patients with osteoarthritis of the hip was set at 2.20 km/h (0.61 m/s). Eight of the 10 gait parameters assessed increased significantly with changing gait speed. Pathological changes in gait patterns were found at the three gait speeds investigated, with the changes more accentuated at higher speeds. Conclusions. Dependence of gait parameters on gait speed could be concluded for a group of patients and for control subjects. Use of a force-instrumented treadmill is necessary for the setting of a standard gait speed, which should be set as high as achievable by patients without inducing pain and problems of coordination or balance. With the usage of standardised speeds, clinical gait analysis becomes easier to perform. Furthermore, one can assess the expected biomechanical advantages of newer prostheses, thus providing the surgeon with a basis for further decisions. [ABSTRACT FROM AUTHOR]

Despite extensive acetabular bone defects as found in revisions of total hip arthroplasty for high hip dislocation, the ilium usually still provides secure fixation of the pedestal of the acetabular component. Four cases are presented in which reconstruction was performed using a newly developed, conical, titanium, ribbed shaft socket designed for cementless press-fit into the dorsocranial ilium to obtain primary stability. In each case the pedestal cup allowed restoration of the original centre of rotation. There were no complications. A Harris hip score of 85 points was achieved after an average of 28.5 months. All components were radiologically stable. While the findings demonstrate the short-term efficacy of the procedure, longer follow-ups and a larger number of patients are needed before the durability of this reconstructive technique can be assessed. [ABSTRACT FROM AUTHOR]

The objective of the present animal experimental study was to determine the effect of initial graft tension (1 N, 7.5 N, 17.5 N) on the biomechanical and histological behavior of the anterior cruciate ligament (ACL) graft using a rabbit model. After 2, 8, and 32 weeks, the femur-ACL-tibia complex was removed, and biomechanical and histomorphometrical studies were performed. The morphometric parameters cellularity, cell nucleus volume, and vascularity increased up to the 8th postoperative week and showed significant differences between the study groups. The values obtained demonstrated that higher pretension had increased the pull-out force and stiffness. However, at 32 weeks postoperatively, the pull-out force was significantly below the values of the normal ACL (40.5% at 1 N, 45.1% at 7.5 N, and 50.8% at 17.5 N). In the present study, it was demonstrated that an intraoperatively selected initial tension of 17.5 N induces histomorphometric changes in the graft, which result in a higher biomechanical loading capacity. The results showed that higher initial graft tension resulted in improved histological and biomechanical parameters. Pathological changes in the graft such as an increased central necrosis rate or cartilage damage due to 'overconstraining' of the knee were not observed at the selected initial tensions. [ABSTRACT FROM AUTHOR]

During the period from August 1986 to August 1992, we treated 23 patients with giant cell tumors stage 2 or 3, according to the classification by Campanacci et al.. We analyzed the therapeutic options, complications, local recurrence rate, and functional results after a mean follow-up of 56 months (range 31–89 months). Intralesional resections were performed in 15 and wide resections in 8 patients. The majority of intralesional resections were performed for stage 2 tumors and the majority of en-bloc resections for stage 3 tumors. The overall local recurrence rate was 8.7%, but we observed local recurrence only in intralesional resections. Our experiences suggest that a subtle surgical technique with respect to oncological requirements is the most important element in the avoidance of local recurrence. Stage 2 tumors associated with weight-bearing anatomical structures should be treated with intralesional curettage and bone cement. Stage 3 tumors are limited as to their surgical options and are determined in some cases by their localization and the degree of bone destruction. Wide resections should be reserved mainly for stage 3 tumors. [ABSTRACT FROM AUTHOR]

The significance of obesity as a risk factor for postoperative complications was determined in a consecutive series of 229 cases of revision total hip replacement. The body mass index (BMI) was used as an objective measure to classify the patients. The group-wise analysis of data included all medical and procedure-related complications, the number of fatal cases, operative time, requirement for analgesics, the number of transfusions and perioperative haemoglobin levels. The results of our study demonstrate a clear association between obesity and operative time, whereas no statistically significant relationships were observed between obesity and the other parameters. We conclude that obesity does not have any significant influence on perioperative morbidity and mortality but is clearly related to operation time and, therefore, to higher costs per operation. [ABSTRACT FROM AUTHOR]

Total hip arthroplasty is problematical in the case of high dislocation. To reposition the hip, a femoral shortening osteotomy is necessary in order to prevent damage to the neurovascular structures. This paper describes the implantation of a cementless straight stem in 15 patients using a simple technique with a simultaneous, derotating and shortening osteotomy. Femur fractures, pseudoarthroses, stem loosening, paresis and deep infections were not found. One socket loosening was revised. Fourteen patients had good or very good results in the Merle d’Aubigne score after a median of 4.3 (range 2–5.6) years of follow-up. The surgical technique described enables the initial stable fixation of a standard prosthesis without additional osteosynthesis. Additional advantages include a shorter duration of surgery, a lower complication rate and a more rapid consolidation of the osteotomy. [ABSTRACT FROM AUTHOR]

The duration of the ischemic time in total knee arthroplasty is currently considered to be an important predictor for the development of arterial thrombosis. In the following, we describe two patients with thrombotic occlusions of the popliteal artery. After the first one had been operated on under ischemic conditions, the ischemic time was limited to the cementing phase in the second case on the basis of this experience, but an arterial occlusion occurred in this case as well. In neither case did immediate vascular surgery lead to clinical restrictions. Our observation demonstrates that arterial thromboses can occur regardless of the duration of ischemia and that surgery should therefore be performed without ischemia if risk factors are present. [ABSTRACT FROM AUTHOR]

We report a case in which metallosis occurred due to a ceramic head fracture after revision of a total hip prosthesis. In the primary revision, after retrieval of the head fragments, the firmly incorporated stem was left in place, the PE inlay was replaced, and a metal head was inserted. Subsequently, massive metallosis occurred, leading to loosening of the stem and necessitating a two-stage revision. Examinations of the explanted material showed that microparticles of the fractured ceramic head had come to rest in the new PE inlay, where they led to wear on the metal head. We conclude that the use of a metal/PE articular pairing is contraindicated after a ceramic head fracture and recommend the use of a ceramic/ceramic articular pairing in the event of revision. In the case of the stem remaining in situ, this procedure requires the use of a conical stem adapter in order to minimise the fracture risk of the new head. [ABSTRACT FROM AUTHOR]