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ZusammenfassungIn den letzten Jahrzehnten ist eine Vielzahl von zementfreien Kurzschaftprothesen auf den Markt gekommen. Gemeinsam vereinen sie das Ideal der weichteilschonenden und minimalinvasiven Hüftgelenksendoprothetik mit knochensparenden Implantationstechniken. Hervorzuheben ist die neueste Generation von Kurzschaftprothesen, die schenkelhalsteilerhaltend und kalkargeführt in einer Round-the-Corner-Technik implantiert werden. Die patientenadaptierte Resektionsebene ergibt die Möglichkeit für eine variable Positionierung des Implantates und eine optimale Rekonstruktion der individuellen Hüftgeometrie. Die vielversprechende frühe Datenlage in der primären hüftendoprothetischen Versorgung führt zunehmend zu einer Ausweitung der Möglichkeiten und Grenzen des Kurzschaftes. Insbesondere die individuelle Positionierung in Valgus- oder Varusposition und die resultierende individuelle metaphysäre oder metadiaphysäre Verankerung eröffnet zahlreiche Möglichkeiten, auch abweichende anatomische Hüftgelenksvarianten optimal rekonstruieren zu können. Zunehmend finden daher Kurzschaftprothesen auch Einsatz bei Patienten mit komplexen anatomischen Variationen, Anomalien oder auch bei aseptischen Hüftkopfnekrosen. In Einzelfällen werden sie auch in der Revisions- oder Konversionsendoprothetik eingesetzt. In bestimmten Einzelfällen können diese Implantate auch in der Frakturendoprothetik eingesetzt werden. Wissenschaftliche Untersuchungen hierzu stehen gegenwärtig jedoch noch aus.

In recent decades, a large number of cementless short stems have been introduced to the market. The concept aims at saving soft tissue using minimally invasive surgery and at the same time preserving as much bone as possible. In particular, the latest generation of short stems, which are implanted using a calcar-guided round-the-corner technique, are attracting increasing attention. An individualised resection level allows individual stem alignment and thus an ideal reconstruction of the hip anatomy. The early clinical results of short-stem total hip arthroplasty (THA) are promising and have led to an expansion of the indications and limitations for the use of short stems. In particular, the individual positioning in valgus or varus and the resulting individual metaphyseal or metadiaphyseal anchorage offers various possibilities to reconstruct even abnormal joint morphologies. Consequently, short stems are increasingly used in patients with complex anatomical variations or in cases of osteonecrosis of the femoral head. In some various cases, they can also be used in revision or conversion arthroplasty. In some patients, short stems can also be used after femoral neck fracture. Currently, scientific data on those areas of indication of short-stem THA is scarce.In den letzten Jahrzehnten ist eine Vielzahl von zementfreien Kurzschaftprothesen auf den Markt gekommen. Gemeinsam vereinen sie das Ideal der weichteilschonenden und minimalinvasiven Hüftgelenksendoprothetik mit knochensparenden Implantationstechniken. Hervorzuheben ist die neueste Generation von Kurzschaftprothesen, die schenkelhalsteilerhaltend und kalkargeführt in einer Round-the-Corner-Technik implantiert werden. Die patientenadaptierte Resektionsebene ergibt die Möglichkeit für eine variable Positionierung des Implantates und eine optimale Rekonstruktion der individuellen Hüftgeometrie. Die vielversprechende frühe Datenlage in der primären hüftendoprothetischen Versorgung führt zunehmend zu einer Ausweitung der Möglichkeiten und Grenzen des Kurzschaftes. Insbesondere die individuelle Positionierung in Valgus- oder Varusposition und die resultierende individuelle metaphysäre oder metadiaphysäre Verankerung eröffnet zahlreiche Möglichkeiten, auch abweichende anatomische Hüftgelenksvarianten optimal rekonstruieren zu können. Zunehmend finden daher Kurzschaftprothesen auch Einsatz bei Patienten mit komplexen anatomischen Variationen, Anomalien oder auch bei aseptischen Hüftkopfnekrosen. In Einzelfällen werden sie auch in der Revisions- oder Konversionsendoprothetik eingesetzt. In bestimmten Einzelfällen können diese Implantate auch in der Frakturendoprothetik eingesetzt werden. Wissenschaftliche Untersuchungen hierzu stehen gegenwärtig jedoch noch aus.

The number of total hip arthroplasties (THA) is rising in many industrialized nations. At the same time, the evidence regarding different types of prostheses and fixation techniques is constantly evolving. Therefore, this study aimed to analyze changes in THA by these advancements during the last decade.A retrospective analysis of data provided by the Federal Statistical Office of Germany from 2007 to 2016 was conducted using codes from the German procedure classification system and associated International Statistical Classification of Diseases and Related Health Problems codes. THA procedures were evaluated according to diagnoses, sex, and age of patients, along with the distribution of different prosthesis types. Additionally, changes in these parameters over time were analyzed.From 2007 to 2016 a total of 2 157 041 primary THA procedures were performed in Germany, with an increase of 14.4% over this period. Overall, cementless standard THA (STHA) was used most frequently (50.0%), followed by hybrid variants (18.8%), hemiarthroplasties (15.9%), cemented standard THA (cSTHA; 9.2%), cementless short-stem THA (ssTHA; 4.8%), and hip resurfacing (HR; 0.9%) techniques. During the study period, the number of cSTHA and HR decreased significantly, whereas the use of STHA and ssTHA rose substantially, with a significantly higher application of these procedures in the elderly population. While osteoarthritis of the hip joint was the main indication for THA, several procedure-specific differences were identified.The present data clearly demonstrate an increase in the use of cementless fixation for THA in Germany during the last decade and document a rise in ssTHA in recent years with, in contrast, the use of HR decreasing to a minimum.Die Primärendoprothetik des Hüftgelenks zählt seit Jahren zu den häufigsten operativen Eingriffen in Deutschland. Zur Verbesserung der Versorgungsqualität erfolgte im Jahre 2010 die Einführung des Endoprothesenregisters Deutschland (EPRD). Trotz einer stetigen Verbesserung in den letzten Jahren, beträgt die Gesamtabdeckung an erfassten Endoprothesen hier im Jahre 2017 etwa 63%. Bisher gibt es keine Studie, welche die Epidemiologie sowie die Versorgungstrends aller Hüftendoprothesen auf Grundlage einer Datenbankanalyse untersucht.Grundlage bildete eine retrospektive Datenanalyse der Gesamtzahl der implantierten Hüftendoprothesen sowie deren zeitlichen Entwicklung anhand der Daten aus ICD- und OPS-Codes des statistischen Bundesamtes zwischen den Jahren 2007 und 2016. Hierbei wurden Geschlecht, Alter und die Verteilung der unterschiedlichen Prothesentypen analysiert. Ebenso erfolgte eine Bewertung der zugrundeliegenden Hauptindikation.Von 2007 bis 2016 wurden 2.157.041 Hüftendoprothesen eingeschlossen, wobei hier ein Anstieg von etwa 14,4% über die Zeitspanne zu erkennen war. Unzementierte Geradschaft-Prothesen stellten insgesamt das größte Kontingent (uG;~50,0%), gefolgt Hybrid-TEPs (~ 18,8%), von zementierten Duokopfprothesen (DK;~14,9%), zementierten Geradschäften (zG;~9,2%), Kurzschaftprothesen (KS; ~ 4,8%) sowie Oberflächenersatzprothesen (OFE; ~ 0,9%). Während die Anzahl an zementierten Prothesen (−47,3%) und OFE(−83,9%) im Beobachtungszeitraum allerdings signifikant rückläufig waren, verzeichneten unzementierte Verfahren (+29,5%) und insbesondere Kurzschaftprothesen (+161,8%) einen enormen Zugewinn. Auch hinsichtlich Alter und Geschlechtsverteilung zeigten sich signifkante Unterschiede innerhalb der Prothesentypen. So stellten Frauen 60 Jahre bei zG das größte Patientengut, wohingegen OFE hauptsächlich bei Männern 60 Jahren implantiert wurden. KS dagegen zeigten eine annährend ausgeglichene Geschlechts- und Altersverteilung, wobei der Anteil an Pat.60 Jahren im Verlauf zunehmend war (+10,0%). Hauptindikation bildete in allen Fällen die symptomatische Coxarthrose, wobei der Frakturanteil bei zG, wie zu erwarten, am höchsten war (25,7%). Der Anteil an Hüftkopfnekrosen zeigte keine signifikanten Unterschiede zwischen den Prothesentypen und betrug ca. 2,8%.Diese Studie liefert wertvolle und in dieser Form bisher nicht vorgestellte Informationen hinsichtlich des Patientenkollektivs und der Entwicklung der endoprothetischen Versorgung des Hüftgelenks in Deutschland. Zusammenfassend kann aus den erhobenen Daten geschlossen werden, dass v. a. Kurzschaftendoprothesen sowie unzementierte Verfahren zunehmend an Bedeutung gewonnen haben. Dabei wurde deren Indikation zunehmend auf ein älteres Patientenkollektiv ausgeweitet. Eine stetige Weiterentwicklung der Registerdaten ist dabei von höchster Priorität, um die Versorgungsqualität stetig zu verbessern und auch Revisionsraten zu minimieren.

An inpatient hospital stay of up to 10 days after total hip arthroplasty (THA) is still common in Germany, mostly followed by inpatient rehabilitation. Internationally already widespread concepts for enhanced recovery are increasingly gaining popularity in Germany.The presentation of content and results of a newly implemented enhanced recovery concept in THA.In this single-center, prospective observational study of a consecutive patient collective of a single surgeon, between January 2016 and July 2016, 103 short-stem THA patients were enrolled and treated using a newly introduced enhanced recovery concept. After 6 weeks and 6 months clinical examination was performed regarding function, pain, satisfaction and possible complications.The goal of discharge on day 4 after operation was reached in 61.2% of the patients with a mean postoperative inpatient stay of 4.9 days. After 6 weeks and 6 months respectively, excellent clinical results were achieved with high patient satisfaction. The complication rate was found to be low. Mean hemoglobin concentration decreased by 2.1 g/dl. A fissure of the femur below the implant healed conservatively applying no weight bearing for a total of 6 weeks. A pulmonary embolism that occurred during rehabilitation was also successfully treated. After 6 months one case showed a bursitis trochanterica.Inpatient length of stay can be reduced by enhanced recovery concepts without increasing the risks to patients. Thus, in Germany these concepts will be applied increasingly.Ein stationärer Aufenthalt von bis zu 10 Tagen nach Implantation einer Hüfttotalendoprothese ist in Deutschland nach wie vor keine Seltenheit, zumeist gefolgt von einer stationären Rehabilitationsmaßnahme. International bereits weit verbreitete Konzepte zur raschen Genesung („Enhanced Recovery“) gewinnen auch hierzulande zunehmend an Popularität. Das Ziel der Studie war die Darstellung der Inhalte eines neu eingeführten Enhanced-Recovery-Konzeptes in der modernen Hüftendoprothetik und die Untersuchung der Ergebnisse über einen Zeitraum von 6 Monaten.In dieser monozentrischen, prospektiven Beobachtungsstudie eines konsekutiven Patientenkollektivs eines einzelnen Operateurs wurden zwischen Januar 2016 und Juli 2016 103 Hüft-TEP-Patienten eingeschlossen und mittels eines neu eingeführten ganzheitlichen Enhanced-Recovery-Konzeptes behandelt. Nach 6 Wochen und 6 Monaten erfolgte eine klinische Untersuchung hinsichtlich der Funktion, des Schmerzes, der Zufriedenheit sowie möglicher Komplikationen.Das Ziel einer Entlassung am 4. postoperativen Tag konnte bei 61,2% der Patienten erreicht werden bei einer mittleren postoperativen stationären Verweildauer von 4,9 Tagen. Nach 6 Wochen bzw. 6 Monaten zeigten sich hervorragende klinische Ergebnisse mit einer hohen Patientenzufriedenheit. Die Komplikationsquote stellte sich gering dar. Es zeigte sich im Mittel ein Abfall der Hämoglobinkonzentration um 2,1 g/dl. Eine Fissur des Femurschaftes unterhalb des Implantates konnte konservativ durch Entlastung für insgesamt 6 Wochen zur Ausheilung gebracht werden. Eine in der Rehabilitation aufgetretene Lungenembolie konnte ebenfalls erfolgreich ausbehandelt werden. Nach 6 Monaten zeigte sich in einem Fall eine Bursitis trochanterica.Die stationäre Aufenthaltsdauer kann durch ganzheitliche Enhanced-Recovery-Konzepte gesenkt werden, ohne gleichzeitig die Risiken für Patienten zu erhöhen. In Deutschland werden solche Konzepte zunehmend eine breite Anwendung finden.

Background Short-term results of several short-stem designs have indicated early axial migration. Mid- and long-term results for most designs are lacking. The objective of this study was to evaluate the mid-term migration pattern of a calcar-guided short stem five years postoperative. Methods Implant migration of 191 calcar-guided short stems was assessed by Ein-Bild-Roentgen-Analysis Femoral-Component- Analysis (EBRA-FCA) 5 years after surgery. Migration pattern of the whole group was analyzed and compared to the migration pattern of implants potentially being “at hazard” with a subsidence of more than 1.5 mm at 2 years postoperatively. Influence of preoperative Dorr types (A vs. B vs. C), age ( 70 years), gender (female vs. male), weight ( 90 kg), BMI ( 30) and uni-vs. bilateral procedures on mid-term migration pattern was analyzed. Additionally outcome of varus- and valgus stem alignment was assessed. Results Mean axial subsidence was 1.5 mm (SD 1.48 mm) at final follow-up. Two years after surgery 73 short stems were classified “at hazard”. Of these stems, 69 cases showed secondary stabilisation in the following period, whereas 4 cases presented unstable with more than 1 mm of further subsidence. Stem revision was not required neither in the group of implants with early stabilisation nor the group with pronounced early onset migration. Male gender and heavy-weight patients had a significant higher risk for axial migration, as well as extensive valgus stem alignment, whereas for Dorr type B, compared to A, no statistical difference could be observed. Conclusions In most cases, even in the group of stems being “at hazard”, settling could be documented. While different Dorr types did not show a statistically significant impact on axial migration, particularly in male and heavy-weight patients the risk of continuous subsidence is increased. In those 4 cases with further migration, undersizing of the stem could be recognized. At present, clinical consequences are still uncertain.

Background The number of total hip arthroplasties (THA) is rising in many industrialized nations. At the same time, the evidence regarding different types of prostheses and fixation techniques is constantly evolving. Therefore, this study aimed to analyze changes in THA by these advancements during the last decade. Methods A retrospective analysis of data provided by the Federal Statistical Office of Germany from 2007 to 2016 was conducted using codes from the German procedure classification system and associated International Statistical Classification of Diseases and Related Health Problems codes. THA procedures were evaluated according to diagnoses, sex, and age of patients, along with the distribution of different prosthesis types. Additionally, changes in these parameters over time were analyzed. Results From 2007 to 2016 a total of 2 157 041 primary THA procedures were performed in Germany, with an increase of 14.4% over this period. Overall, cementless standard THA (STHA) was used most frequently (50.0%), followed by hybrid variants (18.8%), hemiarthroplasties (15.9%), cemented standard THA (cSTHA; 9.2%), cementless short-stem THA (ssTHA; 4.8%), and hip resurfacing (HR; 0.9%) techniques. During the study period, the number of cSTHA and HR decreased significantly, whereas the use of STHA and ssTHA rose substantially, with a significantly higher application of these procedures in the elderly population. While osteoarthritis of the hip joint was the main indication for THA, several procedure-specific differences were identified. Conclusion The present data clearly demonstrate an increase in the use of cementless fixation for THA in Germany during the last decade and document a rise in ssTHA in recent years with, in contrast, the use of HR decreasing to a minimum.

Introduction Short-stem THA has become increasingly popular over the last decade. However, implantation technique differs from conventional THA and thus possibly involves a distinct learning curve. The purpose of this study was to evaluate the value of intraoperative radiography and the influence of the surgeon’s experience on intraoperative adjustments in short-stem THA. Methods A total of 287 consecutive short-stem THAs, operated by a total of 24 senior consultants, consultants and residents in training, were prospectively included. Intraoperative radiography was performed after trial reduction. Preoperative planning and intraoperative outcome with regard to positioning, sizing of components as well as resulting offset and leg length were compared. Frequency, reason and type of intraoperative adjustments were documented in relation to the surgeon’s experience. Operation time was assessed. Results One hundred and fifty-six (54.4%) procedures were carried out by one of three senior consultants, and a total of nine consultants and 12 residents in training performed 105 (36.6%) and 26 (9.0%) operations, respectively. In 121 cases (42.2%), intraoperative adjustments were made following intraoperative radiography. Intraoperative adjustments of one or more components were made by senior consultants in 51 cases (32.7%), by consultants in 53 cases (50.5%) and by residents in 17 cases (65.4%), respectively. The most common cause was undersizing of the stem. Operation time varied markedly between groups of surgeons. Discussion Short-stem THA involves a learning curve. Intraoperative radiography is decisive for prevention of malpositioning and undersizing of components, as well as loss of offset and leg length discrepancies. Hence, it should be considered mandatory, especially for less experienced surgeons.

Background In recent years, a variety of short stems have been introduced. To date, mid- and long-term results of calcar-guided short-stem designs have been rarely available. Materials and methods Two hundred and sixteen calcar-guided short stems were included in combination with a cementless cup in a prospective study. Patients were allowed full weight-bearing on the first day postoperatively. Harris hip score (HHS) as well as pain and satisfaction on visual analogue scale (VAS) were assessed during a median follow-up of 61.7 months. Standardised radiographs were analysed at predefined time points regarding radiological alterations such as bone resorption and remodelling, radiolucency, osteolysis and cortical hypertrophy using modified Gruen zones. Results At mid-term follow-up, no revision surgery of the stem had to be performed in the whole collective. At 5 years, HHS was 97.8 (SD 4.7), satisfaction on VAS was 9.7 (SD 0.7), rest pain on VAS was 0.1 (SD 0.5), and load pain on VAS was 0.6 (SD 1.2). Compared to the 2-year results, femoral bone resorption increased significantly at the 5-year follow-up (3.9% versus 42.3%). Rate of femoral cortical hypertrophy remained stable, occurring in a total of 9 hips (4.5%). At the 5-year follow-up, 2 stems (1.0%) showed non-progressive radiolucent lines with a maximum width of 2 mm. Signs of osteolysis were not observed. Compared to the 2-year follow-up, no further subsidence was observed. Conclusions The rate of stem revision (0%) at the mid-term follow-up was remarkable and indicates the principle of using a calcar-guided short stem as being a safe procedure. However, signs of bone-remodelling, indicating some amount of stress-shielding, must be acknowledged at 5 years depending on stem alignment and type of anchorage. Level of evidence IV, Prospective observational study Trial registration German Clinical Trials Register, DRKS00012634, 07/07/2017 (retrospectively registered)

Bone- and soft-tissue sparing short stems are increasingly used in total hip arthroplasty (THA). However, there are a large variety of models of short stems, differing in design and function. Calcar-guided short stems provide an anatomical curvature in the medial calcar region, thus, positioning is done individually alongside the calcar in the "round-the-corner" technique. Depending on the level of the neck's osteotomy, stems can be aligned individually in a large bandwidth of varus- and valgus anatomies. This differs from conventional total hip arthroplasty and potentially includes a severe learning curve. Given that a great variety of caput-collum-diaphyseal (CCD)-angles can be retained, the reconstruction of femoro-acetabular offsets can be achieved precisely. However, particularly extensive varus- and valgus positioning has raised concerns in regard to stability and bone remodeling. The purpose of the present manuscript is to showcase the implantation technique in calcar-guided short-stem THA and to summarize short-term clinical and radiological results.

Background Preservation of hip geometry is important for treatment success in endoprosthesis implantation. Digital planning can be used to estimate postoperative hip geometry. This study examined whether digital planning accurately predicts surgical outcomes for two femoral neck resecting short stem implants, Mayo® (Zimmer) and Metha® (Aesculap). Methods Preoperative digital planning of the short stem and acetabular cup was performed for 191 patients (197 endoprostheses) with hip osteoarthritis. Digital planning was done with mediCAD II (Hectec) to evaluate types of prosthesis stems and sizes, leg lengthening and offset, and angle of stem inclination within the femur. The predicted values for these parameters were compared to the postoperative measurements. A double coordinate system was developed to measure pelvic and femoral distances separately. Individual scale factors were applied to minimize measurement bias. Findings Implantation of the planned short stem prostheses resulted in a mean femoro-acetabular leg lengthening of 4.2 mm (SD 5.8 mm) and a mean femoro-acetabular offset-reduction of 4.2 mm (SD 5.9 mm) in comparison with preoperative planning. Implantation of both stems resulted in increased valgization compared to planning (Metha®, mean 5.4° (SD 3.7°); Mayo®, mean − 3.2° (SD 3.4°)). Interpretation Differences between preoperative planning and postoperative outcomes were greater for femoro-acetabular than for cup-related leg length and offset. On average, leg length was longer than predicted and there was loss of femoro-acetabular offset. Compared with the planning, valgization of the implanted stems was frequently observed.

PURPOSE Despite the fact that new and modern short-stems allow bone sparing and saving of soft-tissue and muscles, we still face the challenge of anatomically reconstructing the femoro-acetabular offset and leg length. Therefore a radiological and clinical analysis of a short-stem reconstruction of the femoro-acetabular offset and leg length was performed. METHODS Using an antero-lateral approach, the optimys short-stem (Mathys Ltd, Bettlach, Switzerland) was implanted in 114 consecutive patients in combination with a cementless cup (Fitmore, Zimmer, Indiana, USA; vitamys RM Pressfit, Mathys Ltd, Bettlach, Switzerland). Pre- and postoperative X-rays were done in a standardized technique. In order to better analyse and compare X-ray data a special double coordinate system was developed for measuring femoral- and acetabular offset. Harris hip score was assessed before and six weeks after surgery. Visual analogue scale (VAS) satisfaction, leg length difference and the existence of gluteal muscle insufficiency were also examined. RESULTS Postoperative femoral offset was significantly increased by a mean of 5.8 mm. At the same time cup implantation significantly decreased the acetabular offset by a mean of 3.7 mm, which resulted in an increased combined femoro-acetabular offset of 2.1 mm. Postoperatively, 81.7 % of patients presented with equal leg length. The maximum discrepancy was 10 mm. Clinically, there were no signs of gluteal insufficiency. No luxation occurred during hospitalization. The Harris hip score improved from 47.3 before to 90.1 points already at six weeks after surgery while the mean VAS satisfaction was 9.1. CONCLUSION The analysis showed that loss of femoro-acetabular offset can be reduced with an appropriate stem design. Consequently, a good reconstruction of anatomy and leg length can be achieved. In the early postoperative stage the clinical results are excellent.

Background Short-stem total hip arthroplasty (THA) potentially offers advantages compared to conventional THA, including sparing bone and soft tissue and being a facilitated and less traumatic implantation. However, the indication is limited to patients with sufficient bone quality. Cemented short-stem THA might provide an alternative to conventional cemented THA. To date, no cemented short stem is available on the market. Methods In the present in vitro study, primary stability of a new cemented short stem was evaluated, comparing standard (undersized stem) versus line-to-line (same-sized stem) cementing techniques, using six pairs of human cadaver femurs. Primary stability, including reversible micromotion and irreversible migration, was assessed in a dynamic material-testing machine. Fracture load was tested and fracture pattern analyzed. Findings Both cementation techniques (standard vs. line-to-line) displayed comparable results with respect to primary stability without any statistical differences (micromotion: 17.5 μm vs. 9.6 μm (p = 0.063); migration: 9.5 μm vs. 38.2 μm (p = 0.188)). Regarding fracture load, again, no difference was observed (3670 N vs. 3687 N (p = 0.063)). In all cases, proximal fractures of Vancouver type B3 occurred. Interpretation The present in vitro study demonstrates that the line-to-line cementation technique, which is favourable regarding the philosophy of short stem THA, can be further pursued in the course of the development of a cemented short stem. Further investigations should address how well the cemented short stem compares to well-established cemented straight-stem designs.

Background:Single-stage bilateral total hip arthroplasty (THA) is an alternative to staged unilateral THA in patients suffering from bilateral hip arthritis; however, there is still broad concern regarding the safety and reliability of this procedure. Short-stem THA has emerged in recent years. To date, no data are available on sports and recreational activity levels after single-stage bilateral short-stem THA in the general patient population.Hypothesis:Patients who have undergone single-stage bilateral short-stem THA return to a satisfying level of sports and recreational activity at midterm follow-up.Study Design:Case series; Level of evidence, 4.Methods:A total of 54 consecutive patients (108 hips) were prospectively included. Midterm follow-up was performed in 51 patients (94.4%). The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score and the Harris Hip Score (HHS) were assessed clinically after a mean of 5.2 years. After a mean of 4.9 years, activity levels were assessed using the University of California, Los Angeles (UCLA) activity scale via a questionnaire. Additionally, a detailed evaluation of sports behavior was conducted using an additional questionnaire. Pain and satisfaction with sporting ability were assessed using a visual analog scale (VAS). Complications and revisions were documented.Results:Patients had a mean WOMAC score of 98.0 (range, 60.0-100.0) and HHS score of 97.8 (range, 65.0-100.0) at final follow-up. The mean UCLA activity score was 4.7 (range, 2.0-10.0). An increasing number of patients were active in sports at follow-up compared with before surgery (76.5% vs 60.8%, respectively); 2 patients (3.9%) stopped participating in sports on a regular basis, and 10 (19.6%) commenced with sports after surgery. The most popular activities before surgery were cycling (31.4%), hiking (29.4%), swimming (21.6%), and fitness/weight training (15.7%). At follow-up, most patients were engaged in cycling (35.3%) and fitness/weight training (33.3%), followed by swimming (25.5%) and hiking (19.6%). The duration (hours per week) and frequency (times per week) of sporting activities remained stable. The mean VAS pain level during sports was 1.3 (range, 0.0-7.0). No revision surgery had to be performed.Conclusion:After single-stage bilateral short-stem THA, the study patients returned to satisfying levels of activity at midterm follow-up. Postoperatively, few patients were engaged in high-impact sports; however, more patients commenced with lower impact activities. Satisfaction with sporting abilities was high, and the complication rate in total was low.

Introduction Heterotopic ossification (HO) is known to be a common complication after total hip arthroplasty (THA). The minimal invasive (MIS) modified anterolateral approach has become popular in combination with a short stem. We analysed the incidence of HO following short-stem THA using this approach in combination with a postoperative administration of nonsteroidal anti-inflammatory drugs (NSAIDs). Materials and methods 216 short stems were implanted in 162 patients. NSAIDs were administered for 2 weeks after surgery in 154 patients (95.1%). Standardised pre- and postoperative radiographic imaging was done at 2-year follow-up. HO was analysed according to the Brooker classification. Influence of age, gender, body mass index (BMI), and blood transfusion were analysed. Harris Hip Score (HHS) and visual analogue scale (VAS) of satisfaction were assessed. Operation time and blood-transfusion rate was documented. Short-term gastrointestinal side effects were recorded. Results The overall incidence of HO was 7.8% (16 cases). HO Brooker type 3 and 4 occurred in only 1 case (0.5%). No correlation with age, gender or BMI was revealed. HHS improved largely from 45.8 (SD 15.9) before surgery to 98.1 (SD 4.7) after a minimum of 2 years. At that point VAS satisfaction was 9.7 (SD 0.9). Mean operative time was 45.8 minutes (SD 18.7). 12 patients (7.4%) received at least 1 blood-transfusion. Gastrointestinal side effects occurred in 13 of 154 patients (8.4%). Conclusions The combination of short-stem THA, the MIS modified anterolateral approach and a postoperative application of NSAIDs resulted in the effective prevention of HO and excellent clinical results.

Introduction In recent years a variety of short-stems have been introduced. Stable osteointegration is a key factor for a satisfactory long-term result. The purpose of this study was to evaluate postoperative radiological alterations and subsidence, as a result of using a newly developed device, over a 2-year follow-up. Methods 216 short-stems were implanted in combination with a cementless cup. Patients were allowed full weight-bearing on the first day postoperatively. Pre- and postoperative x-rays were done using a standardised technique. Radiological alterations, such as bone resorption, radiolucency, osteolysis and cortical hypertrophy were detected and located using modified Gruen zones, and subsidence was measured via a conventional digital technique over a 2-year follow-up. In addition, Harris Hip Score (HHS), rest pain and load pain on the visual analogue scale (VAS) were assessed respectively. Results At 2-year follow-up 6 stems (2.9%) showed nonprogressive radiolucent lines with a maximum width of 2 mm. Resorption of femoral bone stock was detected in a total of 8 cases (3.9%). Femoral cortical hypertrophy was seen in a total of 9 hips (4.4%). No patient showed osteolysis. A measureable subsidence of at least 2 mm was observed in a total of 15.7% (32 cases) after 6 weeks, corresponding to an initial settlement given full weight-bearing ambulation. Only 1.1% (2 cases) showed further progression at the 6-month follow-up, whereas at the 1- and 2-year follow-ups no further subsidence was observed. After 2 years HHS was 98.1 (65.0-100.0), rest pain on the VAS was 0.2 (0.0-7.0) while load pain was 0.4 (0.0-7.0). Conclusions The results of this radiographic analysis give support to the principle of using metaphyseal anchoring, calcar guided short-stems. The low incidence of bony alterations after a follow-up of 2 years indicates a physiological load distribution. After mild initial subsidence a stable osteointegration can be achieved over time.

External fixation correction of angular deformities leads to secondary translation deformities when occurring around an axis located proximal or distal to the center of rotation of angulation (CORA); secondary length deformities result when correction occurs around an axis concave or convex to the CORA. With circular fixation, the hinge axis can be matched to the CORA. With monolateral fixation, the level of the hinge/angulator is not easily controlled. Axis of correction of angulation can be plotted graphically and secondary deformities calculated trigonometrically. Location of the hinge/angulator can be accurately planned and adjustments incorporated to compensate for expected secondary deformities.