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Background: Periprosthetic Joint Infection (PJI) poses a great challenge to patients, surgeons and health care systems. Comorbid diseases and patient-related risk factors are poorly understood.Objective: The purpose of this study was to evaluate patient-related risk factors for PJI after primary and after revision Total Hip Arthroplasty (THA).Methods: In the present study, data was collected from 566 patients who underwent primary or revision THA between July 2011 and June 2012 in an established arthroplasty center (Endocert certified endoprosthesis center, EPZmax). The effects of demographic data and comorbid diseases on revision operations within 18 months following THA were analyzed using descriptive and explorative statistics.Results: It was shown, that alcohol abuse, depression, preoperative ESBL (Extended Spectrum ß-Lactamase bacteria) infection, elevated preoperative serum-CRP (C-reactive protein), extended operation-time, extended length of hospital-stay, intraoperative complications, perioperative urinary tract infections and postoperative antibiotic therapy are significantly related to PJI in primary THA.Conclusions: Comorbid diseases seem to influence outcome after THA. They are important for predicting revision operations and implant survival. In severe high-risk cases, they can lead to perform the operation under precaution or to avoid performing the operation entirely. This should reduce PJI occurrences in future. [ABSTRACT FROM AUTHOR]

The osteonecrosis of the femoral head implies significant disability partly due to pain. After conventional core decompression using a 10-mm drill, patients normally are requested to be non-weight bearing for several weeks due to the risk of fracture. After core decompression using multiple small drillings, patients were allowed 50% weight bearing. The alternative of simultaneous implantation of a tantalum implant has the supposed advantage of unrestricted load bearing postoperatively. However, these recommendations are mainly based on clinical experience. The aim of this study was to perform a finite element analysis and confirm the results by clinical data after core decompression and after treatment using a tantalum implant. Postoperatively, the risk of fracture is lower after core decompression using multiple small drillings and after the implantation of a tantalum rod according to finite element analysis compared to core decompression of one 10-mm drill hole. According to the results of this study, a risk of fracture exists only during extreme loading. The long-term results reveal a superior performance for core decompression presumably due to the lack of complete bone ingrowth of the tantalum implant. In conclusion, core decompression using small drill holes seems to be superior compared to the tantalum implant and to conventional core decompression. [ABSTRACT FROM AUTHOR]

Osteonecrosis of the femoral head is a more progressive disease for which many patients will eventually require total hip arthroplasty. With the advent of improved metal-on-metal prostheses, total hip resurfacing arthroplasty has emerged as a viable treatment option. However, it remains controversial whether this procedure should be used in patients with osteonecrosis when the femoral resurfacing component is implanted onto non-vital bone. In this study the bone mineral density (BMD) of osteonecrotic femoral heads were compared with the BMD of osteoarthrotic femoral heads. The purpose of this study was to analyse the differences between these two groups to gather information that may be useful in predicting the outcome of total hip resurfacing arthroplasty in cases of severe osteonecrosis of the femoral head. The femoral heads were classified according to the ARCO classification using MRI. For DEXA analysis the femoral heads were subdivided into three regions: the cranial femoral head (R1), the caudal femoral head (R2), and the proximal femoral neck (R3). In R3, BMD in osteonecrotic femoral heads was significantly lower than in those with osteoarthrosis and in R2 it was significantly higher. It can be assumed that a higher BMD in the caudal femoral head (R2) is caused by a "reactive interface" that occurred in this region especially in ARCO IV femoral heads. This fact, the lower BMD in the proximal femoral neck (R3) and the individual expansion of the osteonecrotic region should be considered when planning resurfacing arthroplasty for femoral head necrosis. [ABSTRACT FROM AUTHOR]

Background: In Germany, current revision rates after arthroplasty range between 28-37%. In particular, remaining cement residues are causative for additional revision surgery after periprosthetic joint infection, which is why complete cement removal is of high importance. However, the removal of remaining cement residues often confronts the surgeon with technical challenges. Complication-free and complete cement removal requires extensive preoperative preparation in order to develop the best possible surgical strategy., Treatment: Special instrument sets to facilitate cement removal in revision cases are available from various manufacturers. In addition to endoluminal approaches, access enhancements such as extended osteotomies exist to facilitate complete cement removal. Finally, the surgeon should be able to give the indication for an intraoperative procedural change after a defined time interval., (© 2023. The Author(s).)

Background: The number of operations concerning revision arthroplasty has been increasing continuously in recent years, and it can be assumed that they will continue to increase in the future. If an arthroplasty implant becomes loose, it must be changed. The question often arises as to how the new implant should be fixed in the bone., Advantages: Revision implants can be inserted into the bone without cement. In the subsequent period, a secondary osseointegration of the implant takes place. Another possibility is to anchor the implant by using bone cement. The advantage of cemented anchorage is that the implant is firmly fixed in the bone, in principle, immediately, and it is possible to fully load the implant directly. Direct postoperative full weight bearing is helpful, especially for older and multimorbid patients, in order to achieve rapid mobilization., Prerequisites and Challenges: When using cement in revision cases, however, there are a few prerequisites and challenges that the surgeon should definitely take into account. In the case of revision, the bone in the former implant bed is often deficient and appears thinned and sclerosed. It is, therefore, important to analyze the bone quality preoperatively on radiographic images and to include it in the planning of the anchoring strategy. In addition, the individual bone quality of the patient must also be taken into account intraoperatively. In any case, it must be clarified whether the basic prerequisites for the sufficient bond strength of the cement with the bone to be formed can still be met. Furthermore, the principles of cementing technique must be strictly observed, and the goal of a perfect cement mantle must be aimed for. If the indication for this is overstated, early loosening of the cemented revision arthroplasty is very likely., (© 2023. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

This study analyzed the migration of a calcar-guided short stem to determine the course of very early migration, as well as evaluated the effect of an additional calcium phosphate (CP) coating on a titanium plasma spray (TPS) coating, which has not been analyzed previously. Sixty patients were enrolled in this study and were treated with the A2 calcar-guided short stem. The implant coating was randomized with either the TPS or an additional CP coating, and radiostereometric analysis was performed with the baseline measurement before initial weight-bearing, along with follow-up examinations at 1 week, 6 weeks, 3 months, and 6 months. Implant migrations were 0.27 mm (standard deviation [SD], 0.13 mm) and 0.74 mm (SD, 1.11 mm) at 1 week and 6 months post-surgery, respectively, and 65% and 87% of the implants reached their final position 1 week and 6 weeks after surgery, respectively. After 6 weeks, 3 months, and 6 months, a significant increase was noted in the migration of the CP coating group vs. that of the TPS coating group. Upon the final observation at 6 months, the groups displayed on average a 0.74-mm migration. Most of the analyzed implants ceased migration within the first week post-surgery, but the CP coating demonstrated a higher and more prolonged migration compared to the TPS coating., (© 2024. The Author(s).)

Background: Pelvis fractures are commonly stabilized by surgical implants to facilitate their healing. However, such implants immobilize the iliosacral joint for up to a year until removal. We report how iliosacral joint immobilization affects the walking of patients., Methods: The gaits of patients with immobilized sacroiliac joints after unstable pelvic fracture ( n = 8; mean age: 45.63 ± 23.19; five females and three males) and sex- and age-matched healthy control individuals ( n = 8; mean age: 46.50 ± 22.91; five females and three males) were recorded and analyzed using a motion capture system. The forces between the tread and feet were also recorded. Standard gait parameters as well as dynamic patterns of joint angles and moments of the lower extremities were analyzed using the simulation software OpenSim., Results: With the exception of hip extensor strength, the monitored joint parameters of the patients showed task-dependent deviations during walking, i.e., plantarflexor force was increased when stepping on an elevated surface, as were hip flexion and extensor moments, knee flexion and extensor moments, as well as ankle dorsiflexion and the associated negative plantarflexor force during stance on the elevated surface., Conclusions: Iliosacral joint fixation causes reduced forward and upward propulsion and requires an extended range of hip motion in the sagittal plane. Patients show significant mobility limitation after iliosacral screw fixation.

Background: The EndoCert initiative does not yet allow a long-term assessment of outcome quality. The assessment cannot be achieved without cooperation with the German arthroplasty registry (EPRD) and other quality assurance infrastructure, such as the quality assurance system of the nationwide healthcare insurance data for inpatient hospital treatment (QSR) by the German local healthcare fund (AOK). Therefore, the quality of care of all certified centres for joint replacement (EPZ) after primary hip and knee arthroplasty was to be examined for the first time. These data were subsequently compared to the data of the EPRD., Materials and Methods: In EPZ that provided care to at least one AOK-insured patient in 2016, the risk-adjusted 3‑year revision rate and the SMR-value (standardised mortality or morbidity ratio), which is the quotient of the observed and expected revision rate, were analysed as markers for the quality of care. Annual hospital volume, type of centre and audit results were examined as possible influencing factors., Results: In the group comparison, significant differences (p = 0.042) for the SMR value of the 3‑year revision rate were demonstrated for hip arthroplasty with regard to the EPZ type. The annual number of primary hip arthroplasties, however, did not influence the 3‑year revision rate. For knee arthroplasties, no effect of the defined categories on the 3‑year revision rate and its SMR value was observed. The comparison of our 3‑year revision rates with those of the EPRD showed similar results for the hip but indicated significant differences for the knee., Conclusion: We did not observe a correlation between quality of care and annual hospital volume in certified EPZ. However, different quality assurance procedures can lead to different results with respect to the outcome quality. Therefore, a considerably improved interaction of the German quality systems must be achieved. Participation in the EPRD is not sufficient for this. Rather, a complete report of all arthroplasties must be required, at least with the achievement of a minimum reporting rate per participating hospital. Uniform inclusion and exclusion criteria should be defined., (© 2023. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Background: Periprosthetic acetabular fractures are considered to be a severe and challenging complication in total hip arthroplasty. To date, there are no internationally applicable standardized recommendations which can assist orthopedic surgeons and trauma surgeons in the treatment of patients., Objective: The aim of this article is to report on the current state of knowledge on periprosthetic acetabular fractures, to present the commonly used classification systems and to demonstrate appropriate treatment algorithms together with personal experiences., Material and Methods: A selective search of the existing literature was carried out and the commonly used classification systems and treatment options for periprosthetic acetabular fractures were compiled and are discussed in relation to the in-house cases., Results: The comparison of the classification systems showed that frequently only fractures which have a purely traumatic origin are included among periprosthetic acetabular fractures. Insufficiency fractures within the framework of acetabular defects, which also belong to the group of acetabular fractures, are frequently included in revision arthroplasty. The management of defects with appropriate implants represents a challenge. By the combination of osteosynthesis and implant replacement, the selection of implants can often be de-escalated., Conclusion: Periprosthetic acetabular fractures represent a complex operation for both trauma surgeons and for specially trained orthopedic surgeons, which necessitate a high level of expertise. By the cooperation between trauma surgeons and orthopedic surgeons good treatment results can be achieved and recommendations for the selection of implants can be made., (© 2022. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Background: A short stem hip arthroplasty can be revised in many cases using a conventional stem. Furthermore, in some cases the implantation of a short stem is intended, but intraoperatively reasons may lead to the decision to implant a conventional stem after previous preparation of a short stem., Objective: In both cases it is questionable if the anchorage of a conventional stem is negatively affected by the previous preparation of a short stem. In clinical practice mid- or long-term follow up for these special cases hardly exist., Methods: The strain patterns for the conventional Bicontact stem in primary implantation and after preparation of the proximal femur for a METHA short stem were tested biomechanically in three pairs of cadaveric femora., Results: The strain patterns for the conventional Bicontact after preparation of the METHA short stem were similar to conditions after testing the conventional stem in primary conditions., Conclusions: These data lead to the consequence that in clinical practise the implantation of a conventional stem after preparation of a short stem and even after revision of a short stem is possible without increased risk of loosening or long-term stress-shielding.

Background: The periprosthetic joint infection (PJI) is a severe complication in the field of arthroplasty. Despite the rising number of primary joint replacements, no unified therapeutic standard has been established for the treatment of PJI yet., Methods: A survey on the principles of treatment of PJI in Germany was conducted. A total of 515 EndoProthetikZentren (EPZ) were included, resulting in a response rate of 100%., Results: For early infections 97.6% of the centers use prosthesis-preserving procedures (DAIR). A one-stage exchange was implemented by less than 50% of the centers. If implemented, this treatment entails a prior selection of patients for a successful treatment. The two-stage exchange is performed in all centers, and most centers proceed with the implantation of a cemented spacer between stages. 75% of the centers proceed with a center-based concept for the treatment of PJI., Conclusion: The aim of a uniform PJI standard at the centers has not yet been fully achieved. Further improvements within the certification were initiated. The most relevant treatment options in Germany are displayed. The two-stage revision with a cemented spacer is the most widely implemented treatment. This exposition of principles could help for the further development of standardized treatment guidelines and definitions.

Background: Periprosthetic fractures of the knee joint are complex injuries and frequently represent a challenge for the surgeon., Objective: The aim of this review is to present and discuss the current classification and treatment options for periprosthetic knee fractures., Material and Methods: A selective review of the existing literature on periprosthetic fractures around the knee was performed in PubMed. The various classifications and treatment regimens are discussed with respect to the advantages and disadvantages and from this knowledge a new algorithm was developed., Results: The classifications of periprosthetic fractures have changed in recent years and have been replaced by a uniform fracture classification; however, not only the radiological evaluation of the fractures is crucial to determine the treatment regimen for periprosthetic fractures. A thorough evaluation of the inserted endoprosthesis should be carried out in order to be able to decide between the treatment options of osteosynthesis and revision arthroplasty. Treatment options are available for osteosynthesis and revision arthroplasty that enable a safe treatment of these complex injuries., Conclusion: Periprosthetic fractures of the knee joint are complex injuries, requiring a thorough preoperative planning and an interdisciplinary treatment with trauma and endoprosthetic expertise.

Background: Management of acetabular bone loss is a demanding problem in revision total hip arthroplasty., Objectives: The aim of this review is to introduce and discuss the results and the advantages and disadvantages of custom-made implants as a treatment option for severe acetabular bone defects., Materials and Methods: A selective review of the existing literature of custom made acetabular implants was performed on PubMed., Results: Studies showed good clinical and radiological outcomes of custom made acetabular implants and a survival rate of more than 90%., Conclusion: Custom-made acetabular implants are a reliable treatment option for severe acetabular defects and allow the reconstruction of the centre of rotation of the hip. The costs of these implants are high and planning is time consuming.

Idiopathic toe walking (ITW) causes a common problem in pediatric orthopaedics. In the literature, numerous treatment options have been reported, but consensus about the management of ITW is still missing. The aim of the current study was to evaluate conservative treatment with pyramidal insoles. A total of 193 patients underwent conservative treatment between January 2010 and June 2013. Mean age at the beginning of the treatment was 7.75 ± 0.23 years (range 2.0-17.0 years). For all patients, demographic data, comorbid diseases, passive range of motion (ROM), persistent toe walking, and performed operations were retrospectively evaluated. Following operative treatment was defined failure. Eight (4.15%) patients underwent Achilles tendon lengthening operation after mean therapy time of 2.72 years (range 0.1-7.0 years), 174 cases were treated successfully (90.16%). In 50 cases, toe walking suspended completely after mean therapy time of 2.83 years. In cases of failure, patients were older at diagnosis and at the beginning of the treatment. Mean passive ROM increased over the time. In cases of failure, ROM decreased from the first to the second examination. Conservative treatment of ITW using pyramidal insoles can be effective. Ankle dorsiflexion significantly improved in the patients who were successfully treated. Therapy should start early. A decrease of ROM under therapy should lead to critical revisal of individual therapy. Levels of Evidence: Therapeutic, level IV: Case series.

Purpose: The proposed advantages of short stem hip arthroplasties are bone preserving strategies and less soft tissue damage. Bone preserving strategies do not only include a more proximal resection of the femoral neck, but especially for short stem hip arthroplasties with predominantly metaphyseal fixation a presumed more physiologic load transfer and thus a reduction of stress-shielding. However, the hypothesized metaphyseal anchorage associated with the aforementioned benefits still needs to be verified. Unfortunately, mid- to long-term clinical studies are missing., Methods: Therefore, the METHA short stem as a short stem with proposed metaphyseal anchorage and the Bicontact® standard stem were tested biomechanically in three pairs of cadaveric femora while strain gauges monitored their corresponding strain patterns., Results: For the METHA stem, the strains in all tested locations including the region of the calcar were similar to conditions of cadaver without implanted stem. The Bicontact stem showed approximately half of strain of the non-implanted cadaveric femura with slightly increasing strain from proximal to distal., Conclusions: Summarizing, the current study revealed primary metaphyseal anchorage of the METHA short stem and a metaphyseal-diaphyseal anchorage of the Bicontact stem.

The main goal of total hip arthroplasty is to reduce pain. But function, stability, and longevity are also of major importance. Since the inauguration of modern total hip arthroplasty by Charnley, the designs of stems has undergone many changes. The following paper concerns the straight stem, the anatomical stem and the short stem in total hip arthroplasty. It attempts to answer the question as to whether there is a recommendation for the use of a special stem. The straight stem is the oldest of these stem types. Depending on the particular design, the anchorage of these stems may lie in the metaphyseal or the diaphyseal parts of the femur. The closer the contact of the stem is to the diaphyseal part, the greater is the risk of stress shielding. The anatomical stem attempts to match the geometry of the proximal femoral endosteal. This can be helpful to reconstruct the natural load bearing but has also limitations in fitting. The short stem was designed to achieve an anatomical pattern of stress distribution, resection of less bone and reduction in thigh pain. There are additional differences between the designs. But not only the stem design has to be considered. The proximal part of the femur exhibits a great variety of morphologies. Whereas younger patients mostly have secondary osteoarthritis due to deformities, elderly patients may have changes in morphology due e.g. osteoporosis. Depending on these patient-specific factors and bearing biomechanical aspects in mind, the surgeon must choose the stem design. This may require different stem designs with different mechanisms of fixation., Competing Interests: Gabriela von Lewinski ist als Referentin und Workshop-Instruktorin für die Firma B. Braun Aesculap AG tätig., (Georg Thieme Verlag KG Stuttgart · New York.)

Background: Total hip arthroplasty (THA) is one of the most common orthopedic procedures in developed countries, and the high volume of surgery and the socioeconomic burden of failures demand continuous optimization. Operative time has been identified as a significant independent factor influencing the clinical outcome of THA., Objective: The aim of this study was to analyze factors influencing the operative time for THA in a large, single-center cohort., Methods: A consecutive series of 7,674 cases undergoing primary THA was identified, and after multiple imputation of missing values, univariable and multivariable linear regression analyses were performed., Results: In the univariable analysis, all factors showed significant influences on operative time, while multivariable regression analysis revealed that sex, a diagnosis of hip dysplasia and small femoral component size did not reach significance. Younger age, an underlying diagnosis other than osteoarthritis or hip dysplasia, a large stem size, usage of a conventional stem rather than a short stem, a larger cup size and a cemented fixation technique, however, remained significantly influential in terms of a longer operative time., Conclusions: This study identified risk factors for longer operative time that in turn is associated with a higher rate of periprosthetic joint infection and impaired clinical outcome. Our findings could help to refine scheduling of total hip arthroplasty procedures in times of increasing cost and efficiency pressure.

Purpose: Local cartilage and bony defects, which are too large for joint preserving cartilage treatment are difficult to treat. The implantation of a mini-resurfacing implant (Hemicap®, 2med, Hamburg, Germany) may be a possible alternative treatment for these patients. This partial replacement fills the defect and restores a smooth and continuous articular surface. The aim of this study was to determine short- to midterm results of the treatment of local cartilage defects of the femoral head using the Hemicap®., Methods: Since 04/2011 16 patients with osteonecrosis of the femoral head greater ARCO stage II or local femoral cartilage lesions (< 35 mm) were treated with the implantation of the Hemicap® implant. A clinical and radiological follow-up was conducted., Results: The clinical results showed a significant improvement of the function and pain of the hip according to the Harris Hip Score from 56 (±14) preoperative to 77 (±15) post-operative 25 months after implantation of the Hemicap®. In the meantime, in four patients the Hemicap® had to be converted to a total hip arthroplasty due to loosening, progredience of the osteonecrosis or degeneration of the acetabulum., Conclusions: The implantation of the mini-resurfacing implant Hemicap® seemed to be an alternative treatment for local cartilage defects of the femoral head to postpone the implantation of a total hip arthroplasty. However, the clinical outcome seems to be inferior to total hip arthroplasty. Furthermore, due to a high rate of conversion to total hip arthroplasty (25%) the application of this implant is questionable. If the implant is considered as a treatment option at least patient selection and enlightenment for this treatment with the high risk of failure and progression of osteoarthritis is very important.

Over the last decade, the number of short stem total hip arthroplasty procedures has increased. Along with the possible benefits associated with short stems is a smaller implant-bone contact surface, which may have a negative influence on primary stability and impair osseointegration. Previous studies observed migration of short stems, especially within the first three months. The variables that influence migration in short stem hip implants remain unknown. Therefore, the purpose of this study was to associate the migration of short stems with its possible influencing variables. Migration data from two different short stem studies were retrospectively analyzed. Migration within the first two postoperative years was determined by model-based Roentgen stereophotogrammetric analysis. Migration was correlated to bearing couple, type and size of stem, size of acetabular cup, and age, gender, weight, and height of patients using a multiple factor analysis. Eigenvalue analysis explained 80.7% of the overall variance for the first three dimensions. The four most dominant variables in the first dimension were weight, stem size, acetabular cup size, and patient height (correlations of 0.81, 0.80, 0.71, and 0.70, resp.). None of the analyzed parameters (bearing couple, type and size of stem, size of acetabular cup, and age, gender, weight, and height of patients) affected the migration pattern of short stem THA with primary metaphyseal fixation.

We examined our experience and, in particular, complications associated with total hip arthroplasty in obese and morbidly obese patients. We prospectively gathered 50 patients in a matched control series including 25 obese and morbidly obese patients. All patients were operated using the direct lateral approach and standard postoperative protocols. Operating room time, complications, dislocations, blood loss, cup position and clinical parameters using the Harris Hip Score and the Western Ontario and McMaster Universities Arthritis Index results were compared. Although there were some significant differences in clinical outcomes, standard procedures yielded good overall results and an acceptable rate of complications. Details approaching this patient entity are being discussed.

Implant migration can be accurately quantified by model-based Roentgen stereophotogrammetric analysis (RSA), using an implant surface model to locate the implant relative to the bone. In a clinical situation, a single reverse engineering (RE) model for each implant type and size is used. It is unclear to what extent the accuracy and precision of migration measurement is affected by implant manufacturing variability unaccounted for by a single representative model. Individual RE models were generated for five short-stem hip implants of the same type and size. Two phantom analyses and one clinical analysis were performed: "Accuracy-matched models": one stem was assessed, and the results from the original RE model were compared with randomly selected models. "Accuracy-random model": each of the five stems was assessed and analyzed using one randomly selected RE model. "Precision-clinical setting": implant migration was calculated for eight patients, and all five available RE models were applied to each case. For the two phantom experiments, the 95%CI of the bias ranged from -0.28 mm to 0.30 mm for translation and -2.3° to 2.5° for rotation. In the clinical setting, precision is less than 0.5 mm and 1.2° for translation and rotation, respectively, except for rotations about the proximodistal axis (<4.1°). High accuracy and precision of model-based RSA can be achieved and are not biased by using a single representative RE model. At least for implants similar in shape to the investigated short-stem, individual models are not necessary. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:903-910, 2016., (© 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

Introduction: Osteonecrosis of the femoral head (ONFH) is a locally destructive and complex disorder. Without treatment, infraction of the femoral head is likely. There is also a lack of consensus in the literature about the most appropriate arthroplasty method in patients with progressive ONFH. During the last decade, the number of short-stem prostheses has increased. Some short-stem designs have a metaphyseal anchorage. It is questionable whether ONFH represents a risk factor for failure after implantation of short stems. The aim of this study was to review existing literature regarding the outcome of short-stem arthroplasty in ONFH and to present the pros and cons of short-stem hip arthroplasty in osteonecrosis of the femoral head., Materials and Methods: This review summarises existing studies on short-stem hip arthroplasty in osteonecrosis of the femoral head., Results: Few studies have analysed the clinical and radiological outcome of short-stem THA in patients with ONFH. Only a handful of studies present clinical and radiological outcome after implantation of a short-stem arthroplasty in patients with the underlying diagnosis of osteonecrosis of the femoral head., Conclusion: The short- to medium-term results show predominantly good outcomes. However, due to differences in the design of short stems and their fixation, it is hard to draw a general conclusion. Short stems with primary diaphyseal fixation do not reveal a high increased risk of failed osseointegration or loosening. For designs with a primary metaphyseal anchorage, an MRI should be conducted to exclude that the ostenecrosis exceeds the femoral neck.

Since 1998, short stem total hip arthroplasty (THA) has been performed at the authors' institution. Currently, 30% of THAs are performed with short stems. This article reports on complications that required revision of a short stem THA. Between September 2005 and February 2012, a total of 1953 Metha short stem THAs were performed; of these, 38 required revision due to mechanical complications. In 12 cases, the modular titanium neck adapter failed. In 19 cases, aseptic implant loosening occurred; of these, 11 cases were due to major stem subsidence. In 2 cases, via falsa (cortical penetration) implantation occurred. In 5 cases, periprosthetic fractures led to revision. This corresponds to an aseptic total revision rate of 1.3% for 26 short stems and 1.9% including the cases of all 38 documented revision cases. Thirty-four cases were revised with cementless standard hip stems, 2 cases were revised with short stems, and 2 cases were revised with long revision stems. Undersizing was analyzed in 58% of aseptic revisions. Fifty-four percent of revisions were performed in male patients - 23% with osteonecrosis of the femoral head, and 7% with short hip stems positioned in varus in coxa vara deformities. Seventy-two percent of revisions after marked early stem subsidence and position change into valgus were performed in female patients. Dysplastic hips with coxa valga did not show elevated revision rates. No revisions were performed for dislocation or femoral thigh pain. Short stem THA with the Metha implant is a bone-preserving option for various indications in select patient groups., (Copyright 2015, SLACK Incorporated.)