Why Is There a Range in Time Returning to Preoperative Activity Habits After Femoroacetabular Impingement Treatment in Recreational Athletes?

CONTEXT: Professional athletes showed excellent results after hip preserving procedures. However, there is still a lack of knowledge regarding the rate of return to activity and the rehabilitation time of recreational athletes. Thus, the aim of this study was to investigate factors that were associated with an extended return-to-activity time in nonprofessional athletes. DESIGN: Retrospective, quantitative case-control study. METHODS: This study included 47 cases (45 nonprofessional athletes), which were divided according to return-to-activity time (short term: 0.0-7.0 mo vs long term: >7.0 mo). The clinical outcome were evaluated with the modified Harris hip score, the nonarthritic hip score, the Western Ontario and McMaster Universities Osteoarthritis Index, and the University of California, Los Angeles activity score. For statistical analysis between both groups, an unpaired student t test and a paired Wilcoxon test were used. In addition, the sports behavior, intraoperative findings, and surgical procedures were also assessed. RESULTS: After a mean follow-up of 4.3 years (±0.6; 3.4-5.6), the overall postoperative modified Harris hip score was 81.8 points, the nonarthritic hip score was 75.8 points, the Western Ontario and McMaster Universities Osteoarthritis Index was 36.7 points, and the University of California, Los Angeles activity score was 7.9. Compared with the preoperative results, all scores improved significantly (P < .001). Patients of the short-term return-to-activity group showed a higher preoperative activity diversity and, postoperatively, a higher rate in high-impact sports (P = .024). CONCLUSIONS: After mini-open arthrotomy for femoroacetabular impingement syndrome treatment, 92.5% of the recreational athletes returned to sports activity. The findings did not detect factors influencing the return-to-activity time. However, a higher preoperative diversity of activities and a shift to high-level impact sport activities might support a shorter rehabilitation.

The lateral joint space width is essential for the outcome after arthroscopically assisted mini-open arthrotomy for treatment of a femoroacetabular impingement: an analysis of prognostic factors for the success of this hip-preserving technique.

PURPOSE: The purpose of this study was to analyze predicting factors for a conversion to a total hip replacement (THR) after mini-open arthrotomy for treatment of femoroacetabular impingement (FAI). METHODS: Between 2011 and 2016, we identified 32 patients, who were treated for FAI with a mini-open arthrotomy and received after mean time of 2.1 ± 1.4 years a THR. These patients were compared to 47 cases who did not receive a THR (mean follow-up: 4.3 ± 0.7 years) to explore pre- and intra-operative factors associated with a conversion to THR. The results were presented in separated Kaplan-Meier curves with log rank test for significance and hazard ratios. RESULTS: A lateral joint space width of > 4 mm showed a higher THR-free survival rate compared to < 4 mm (p = 0.001); analogously one-sided (acetabular/femoral) 3-4° cartilage damage had a comparable THR-free survival rate than 1-2° kissing lesions (p = 0.001). Furthermore, an intact labrum without treatment and good cartilage status, a refixed labrum after rim resection in case of a pincer type FAI, or a refixed teared labrum were associated with a longer THR-free time than an untreated labrum accompanied by a poor cartilage status or an ossified labrum (p = 0.002). The strongest independent factor for a conversion to THR was femoral cartilage damage grade 1 and higher (p = 0.046). However, the rate of available patients was 53.0%. CONCLUSION: The success of a joint-preserving mini-open arthrotomy seems to be dependent on the status of the radiological joint space width and the intra-operative cartilage status of the lateral edge.

Cell culture media notably influence properties of human mesenchymal stroma/stem-like cells from different tissues.

BACKGROUND AIMS: Mesenchymal stroma/stem-like cells (MSCs) are a popular cell source and hold huge therapeutic promise for a broad range of possible clinical applications. However, to harness their full potential, current limitations in harvesting, expansion and characterization have to be overcome. These limitations are related to the heterogeneity of MSCs in general as well as to inconsistent experimental protocols. Here we aim to compare in vitro methods to facilitate comparison of MSCs generated from various tissues. METHODS: MSCs from 3 different tissues (bone marrow, dental pulp, adipose tissue), exemplified by cells from 3 randomly chosen donors per tissue, were systematically compared with respect to their in vitro properties after propagation in specific in-house standard media, as established in the individual laboratories, or in the same commercially available medium. RESULTS: Large differences were documented with respect to the expression of cell surface antigens, population doubling times, basal expression levels of 5 selected genes and osteogenic differentiation. The commercial medium reduced differences in these parameters with respect to individual human donors within tissue and between tissues. The extent, size and tetraspanin composition of extracellular vesicles were also affected. CONCLUSIONS: The results clearly demonstrate the extreme heterogeneity of MSCs, which confirms the problem of reproducibility of results, even when harmonizing experimental conditions, and questions the significance of common parameters for MSCs from different tissues in vitro.

The etiology of revision total hip arthroplasty: current trends in a retrospective survey of 3450 cases.

INTRODUCTION: Over the last years, the design of implants, the surgical approaches, and diagnostic tools changed in primary and revision of total hip arthroplasty. A knowledge of the different causes for revision after total hip arthroplasty is essential to avoid complications and failures. The purpose of this study was to determine trends of the etiology of implant failures over the last years by analyzing indications of revision hip arthroplasty. METHODS: All the patients who performed revision hip arthroplasties in our institution between 2001 and 2015 were reviewed retrospectively. Patient demographics, the indication for revision surgery as well as the procedure were assessed. Descriptive statistical analyses and association analyses were performed. RESULTS: Within our collective of 3450 revision hip arthroplasties, a total of 20 different indications were identified and categorized. Overall, 80.8% of the revisions were categorized as aseptic, 19.2% as septic implant failures. Some recently debated diagnoses like low-grade infection showed a high increase in incidence, whereas classic failure mechanisms like polyethylene wear showed a decrease over the time. In addition, the data revealed that cup loosening caused more revision surgeries than stem loosening. CONCLUSION: This study successfully updated the current knowledge of different failure mechanisms in revision hip arthroplasties. The data proved that cup loosening was the most common failure mechanism in older patients, while in young patients, septic complications showed a high incidence. Probably, due to improved diagnostic tools, the percentage of infection in revision hip arthroplasty increased over the years.

Greater early migration of a short-stem total hip arthroplasty is not associated with an increased risk of osseointegration failure: 5th-year results from a prospective RSA study with 39 patients, a follow-up study.

Background and purpose - Short-stem hip arthroplasty has been a viable alternative to standard stems for the treatment of hip osteoarthritis for over 10 years. This study assessed whether a correlation existed between a greater initial increase in implant migration and inferior clinical outcomes at 5 years postoperatively. Results on these patients after 2 years have been published previously.Patients and methods - Radiostereometry and clinical scoring were undertaken after surgery and at 3, 6, 12, and 24 months, and 5 years postoperatively. The migration and the clinical outcomes data from the patients with initial migrations at 3 months above the 75th percentile (≥ 75% group) were compared with those with migrations at 3 months of less than the 75th percentile (< 75% group).Results - Between 3 months and 5 years after surgery, the mean resultant implant migrations were 0.40 mm (SD 0.32) in the ≥ 75% group and 0.39 mm (SD 0.25) in the < 75% group. The mean Harris Hip Scores and SF-36 physical scores at 5 years postoperatively were 100 (SD 0.4) and 44 (SD 12), respectively, for the ≥ 75% group and 99 (SD 2) and 50 (SD 10), respectively, for the < 75% group. The differences between the patient groups were not statistically significant.Interpretation - There was no correlation between a greater initial migration and inferior clinical outcomes at 5 years postoperatively. Despite a greater initial migration, there were no risks of early aseptic loosening and inferior midterm clinical outcomes associated with a short-stem implant with a primary metaphyseal anchorage.

The outcome of the partial resurfacing arthroplasty of the hip shows high numbers of failures and conversion to total arthroplasty.

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.

Analysis of migration of the Nanos® short-stem hip implant within two years after surgery.

PURPOSE: Short-stem implants provide a bone-preserving alternative in total hip arthroplasty. However, some evidence exists that the smaller implant-bone contact surface may compromise primary stability and impair osseo-integration. The purpose of this study was to analyse the migration characteristics of the Nanos® short stem over two years by means of model-based roentgen stereophotogrammetric analysis (MBRSA). METHODS: Eighteen patients aged 53.6 ± 7.2 years were included. After being treated with a Nanos implant, 14 patients were followed-up radiologically at three, six, 12 and 24 months by means of MBRSA. Early implant migration was calculated. Clinical data have been assessed in addition. RESULTS: Highest translational migration was observed with a mean value of -0.22 ± 0.39 mm along the proximo-distal axis after three months and highest rotational migration with 0.8 ± 3.2° also around the y-axis after two years. The resulting total migration was 0.46 ± 0.31 mm, with the largest proportion occurring within three months after surgery (0.40 ± 0.34 mm). CONCLUSION: The Nanos short-stem hip implant shows only a slight initial migration within three months after implantation, followed by secondary stabilisation. These results suggest both good primary stability and osseo-integration, suggesting a low risk of aseptic loosening.

The value of arthroscopic neosynovium biopsies to diagnose periprosthetic knee joint low-grade infection.

INTRODUCTION: The diagnostic algorithm in cases of assumed low-grade infection after total knee arthroplasty is discussed controversial. The aim of this study was to evaluate the reliability of neosynovium biopsies via knee arthroscopies in predicting a periprosthetic knee joint infection (PJI). METHODS: From 2010 to 2015, 56 consecutive patients received a diagnostic arthroscopy of the knee joint by reason of an assumed PJI. In 34 cases, a revision arthroplasty was performed after the diagnostic arthroscopy. The microbiologic and histologic results from neosynovium biopsies were compared to intraoperative findings of the consecutively performed revision arthroplasty. RESULTS: The arthroscopic neosynovium biopsies had a sensitivity of 0.88 (0.47-1.0 95 % confidence interval), a specificity of 0.88 (0.7-0.98), a positive predictive value of 0.7 (0.35-0.93), and a negative predictive value of 0.96 (0.79-1.0). The accuracy was 0.88. We determined a higher sensitivity of neosynovium biopsies compared to C-reactive protein (p = 0.038) and white blood cell count (p < 0.001) in serum. The itemized evaluation of histologic results showed a significant higher sensitivity compared to microbiologic results (p = 0.045) and a higher accuracy. CONCLUSIONS: The analysis of arthroscopic neosynovium biopsies can be helpful to verify or exclude a PJI in selected patients. Especially, histologic assessment showed a high accordance with final results. Level of evidence IV, retrospective study.

Short-stem hip arthroplasty in osteonecrosis of the femoral head.

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.

The influence of resection height on proximal femoral strain patterns after Metha short stem hip arthroplasty: an experimental study on composite femora.

PURPOSE: The number of candidates for a total hip arthroplasty (THA) is steadily increasing, while the average patient age is decreasing for primary THA. The rise in THA is mainly due to excellent clinical outcomes and the extended longevity of modern implants. Short stem arthroplasties with predominantly metaphyseal fixation such as the Metha® stem are suggested for young patients. It is hypothesised that the more physiological load transfer of these devices reduces stress shielding, which in turn may reduce the risk of aseptic loosening. However, patients with femoral deformities often require a deviation of the resection height. To this end, our aim was to evaluate how resection height influences strain patterns in order to characterise possible limits for short stem implantation. METHODS: Biomechanical testing using ten strain gauges on synthetic bone illustrated the strain patterns of three different resection heights (0, +5 and +10 mm) for the Metha stem. RESULTS: The greatest differences in strains were displayed at the "high" (most proximal) resection height (+10 mm) when compared to the non-implanted strain pattern. At the medial calcar, the strain was 143% for +10 mm, 96% for +5 mm and 94% for 0 mm. Overall, discrepancies were less for deeper resections. CONCLUSIONS: The deeper the resection, the more similar the strain patterns are when compared to a non-implanted synthetic bone. Changes in strain patterns are induced by variation in the varus/valgus positioning of the implant and by different offsets.

Analysis of factors affecting the time for implantation of a total hip arthroplasty in patients with symptomatic primary and secondary hip osteoarthritis.

BACKGROUND: Many studies have identified factors associated with an unfavourable clinical outcome or an early conversion to total hip arthroplasty (THA) after joint-preserving treatment. We analysed the effect and reliability of different factors on the age at which THA becomes necessary. METHODS: Hip joint radiographs of 2485 cases were evaluated using the lateral centre-edge angle (LCEA) and acetabulum angle (ACA) as well as the alpha angle to describe the femoral head shapes. Regressions were performed using patient's age at the time of THA and body mass index (BMI) as well as LCEA and ACA. Multiple linear regressions were used to create a formula comprising factors that significantly correlated with patient age at the time of joint replacement surgery. RESULTS: The BMI, LCEA, and ACA showed significant correlations with the age of THA implantation (p < 0.001). Multiple linear regressions produced the following formula: age (THA) = 72.40-0.40 × BMI + 0.20 × LCEA-0.18 × ACA. BMI showed a stronger impact on the age of end-stage osteoarthritis than the ACA. The formula explained 12.1% of the distributing data (r2). Surprisingly, the alpha angle did not show an impact on the age of THA surgery. CONCLUSIONS: BMI had the greatest impact on patient's age at the time of THA, followed by the characteristic radiological angles for hip dysplasia. The resulting formula could emphasise and visualise the significant impact of these factors. However, despite the calculation being based on 2485 cases, the calculated validity of 12.1% was limited.

Bone turnover markers failed to predict the occurrence of osteonecrosis of the femoral head: a preliminary study.

BACKGROUND: The early detection of osteonecrosis of the femoral head (ONFH) is difficult, but important for prevention of destruction of the femoral head. The objective of this study was to determine whether the occurrence of osteonecrosis of the femoral head (ONFH) correlates with changes in bone turnover markers. METHODS: In 40 patients undergoing primary total hip arthroplasty (THA), different bone turnover markers and hormones (bone specific alkaline phosphatase, osteocalcin, beta cross-laps, 25-hydroxy-cholecalciferol, and parathormone) gained from blood were determined on the morning of the surgery. Twenty-two patients needed a THA due to progressed ONFH. In 18 cases blood was gained from patients with the indication for a THA given due to advanced osteoarthritis (AO) of the hip. RESULTS: Bone specific alkaline phosphatase, osteocalcin, beta cross-laps, and parathormone did not show any deviation from standard values, neither for the group of osteonecrosis nor for the osteoarthritis group. 25-Hydroxy-cholecalciferol revealed on average decreased values without significant differences between both groups (P < 0.05). The tested bone turnover markers and hormones failed to predict the occurrence of ONFH. Thus, the focus has to be put on different parameters to find a specific parameter that possibly predicts the risk of ostenecrosis and that is suited to follow up ONFH.

Cementless short stem hip arthroplasty METHA® as an encouraging option in adults with osteonecrosis of the femoral head.

INTRODUCTION: The implantation of a total hip arthroplasty is the standard treatment for patients with progressive osteonecrosis. However, there is uncertainty about the type of arthroplasty that provides the best outcome and whether short stem arthroplasty represents a reasonable alternative for young patients in order to have more options in case of revision. This uncertainty exists due to the lack of studies analysing contemporary short stem arthroplasty in osteonecrosis. AIM: The aim of this study was to determine the outcome of the METHA(®) short stem arthroplasty in patients with progressive osteonecrosis. PATIENTS AND METHODS: This study evaluated the clinical and radiological short- to midterm results after implantation of the cementless short stem arthroplasty METHA(®). 73 hips in 64 patients with progessive osteonecrosis after implantation of the METHA(®) arthroplasty were investigated by measuring the clinical outcome, the Harris Hip Score (HHS) and visual analogue pain scale for the preoperative stage and follow-up. Radiological analyses of X-rays were conducted to assess the bone ingrowth as well as subsidence, osteolysis or fracture. RESULTS: The pain scale improved from preoperatively 7.8 to postoperatively 1.7, while the HHS increased from 41.4 to 90.6 points 34 months post-surgery. Complications associated with revision of the METHA(®) short stem included two traumatic femoral shaft fracture and one deep infection. The radiological assessment showed good bone ingrowth in all patients despite osteonecrosis. CONCLUSION: The study confirms encouraging results as well as good bone ingrowth of the cementless short stem arthroplasty METHA(®) even in patients with osteonecrosis.

Sports activity after pelvic osteotomy for treatment of developmental dysplasia of the hip : A comparative study between the triple pelvic and periacetabular osteotomy techniques.

BACKGROUND: Symptomatic dysplasia of the hip represents an indication for a bony correction of the acetabulum. In the last decades several operative procedures were established. OBJECTIVE: The aim of the current study was to analyze whether the level of sports activity is higher in patients after periacetabular osteotomy (PAO) according to Ganz as a technique which preserves the posterior column compared to classical triple pelvic osteotomy (TPO) for treatment of developmental hip dysplasia. MATERIAL AND METHODS: The study group included 102 patients treated with the classical TPO with already published clinical results, who were compared to 34 patients treated with PAO between 2012 and 2016. The clinical outcome scores included the modified Harris Hip Score, the Hip Osteoarthritis Outcome Score, the University of California, Los Angeles activity score and the visual analog scale. RESULTS: After a mean follow-up of 4.4 years the clinical parameters improved significantly after PAO (p < 0.05). In comparison to the TPO group the clinical scores of the PAO group had inferior baseline values and a tendency to inferior follow-up results in the mHHS (p < 0.05) and HOOS (p > 0.05). After surgery, the PAO group showed a shift to medium and high impact sport activities. CONCLUSION: The shorter time of postoperative partial weight bearing after PAO due to the preservation of the posterior column seemed not to have a positive impact on the clinical results or the sports activity compared to the TPO treated patients.

Correction of severe foot deformities using the Taylor spatial frame.

BACKGROUND: This study was conducted to evaluate the treatment of severe foot deformities using the Taylor spatial frame. MATERIALS AND METHODS: The treatment of seven patients with nine severe foot deformities was reviewed. The mean age of the patients at surgery was 16 years with a mean followup of 21.5 months. The following parameters were assessed: etiology of deformity, date of surgery, surgical procedure, age at surgery, previous surgical or conservative treatments, preoperative symptoms, preoperative and postoperative deformity and affected side, complications during correction, duration of TSF, duration of hospital stay, occurrence of secondary osteoarthritis, recurrence of deformity, surgical revisions or subsequent surgeries. The pre- and postoperative deformity was assessed clinically. The final outcome was categorized as good, fair, or poor. RESULTS: The results were good in eight feet and poor in one foot. Early complications included pin tract infection, temporary hypoesthesia and temporary shortening of the tendon of the flexor digitorum longus. Recurrence of deformity occurred in no patient. One patient required a subtalar arthrodesis for symptomatic, secondary osteoarthritis in one foot. CONCLUSION: The present study showed that TSF is a viable solution to correct severe foot deformities but we believe a surgeon should be aware of the possible complications.

Taylor spatial frame in severe foot deformities using double osteotomy: technical approach and primary results.

PURPOSE: The treatment of severe foot deformities in children or adolescents is complex and demanding to the surgeon. This paper describes the technical strategy of using a Taylor spatial frame and reports on the functional outcome. METHODS: The Taylor spatial frame was used by a single surgeon in patients with severe foot deformities. Seven patients with eight severe deformities were treated. Mean patient age at surgery was 15.1 (9-29) years. A double Taylor spatial frame reconstruction was mounted to the limb. All patients had a midtarsal osteotomy and an additional inverse dome-shaped calcaneus osteotomy. Assessed measures were pre- and postoperative deformity and associated complications and clinical results according to Ferreira et al. RESULTS: Mean follow-up was 576.5 (359-987) days. The final functional outcome according to Ferreira was good in seven cases, fair in none, and poor in one. Early complications included pin-tract infection, temporary hypoesthesia, and temporary shortening of the tendon of the M. flexor digitorum. At follow-up there was no deformity recurrence. CONCLUSION: In children or adolescents, the innovative treatment using the Taylor spatial frame and a double osteotomy allows joint-preserving correction of severe foot deformities. However, the complication rate is relatively high due to the severely deformed feet. Furthermore, the Taylor spatial frame is expensive. Thus, this treatment is only recommended for severe foot deformities and should be handled by experienced orthopedic surgeons.

Core decompression and osteonecrosis intervention rod in osteonecrosis of the femoral head: clinical outcome and finite element analysis.

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.

Clinical and radiological outcome of the treatment of osteonecrosis of the femoral head using the osteonecrosis intervention implant.

The aim of this study was to evaluate the clinical and radiological outcome of the treatment of osteonecrosis of the femoral head by implantation of an osteonecrosis intervention rod. In this retrospective study the follow-up of 19 patients with 23 osteonecrotic femoral heads treated with implantation of an osteonecrosis intervention implant was assessed. From 19 patients with 23 necrotic femoral heads, there were 13 cases in which a total hip replacement was necessary. This implies a survival rate of 44% after implantation of an osteonecrosis intervention rod after a mean follow-up of 1.45 years. The outcome after core decompression combined with the insertion of a tantalum osteonecrosis intervention implant did not show superior results compared to core decompression alone. This is in contrast to existing studies. In addition, this study showed that in cases of total hip replacement, no problems appeared during explantation of the tantalum rod.

Is a Femoro-Acetabular Impingement Type Cam Predictable after Slipped Capital Femoral Epiphysis?

(1) Background: Previous studies have proven a high incidence of a femoro-acetabular impingement (FAI) type cam in patients sustaining a slipped capital femoral epiphysis (SCFE). Thus, the current study analyzed, if a cam deformity is predictable after SCFE treatment; (2) Methods: 113 cases of SCFE were treated between 1 January 2005 and 31 December 2017. The radiological assessment included the slip angle after surgery (referenced to the femoral neck (epiphyseal tilt) and shaft axis as Southwick angle) and the last available lateral center edge angle (LCEA), the acetabular- and alpha angle. A correlation was performed between these parameters and the last alpha angle to predict a FAI type cam; (3) Results: After a mean follow-up of 4.3 years (±1.9; 2.0-11.2), 48.5% of the patients showed a FAI type cam and 43.2% a dysplasia on the affected side. The correlation between the epiphyseal tilt and alpha angle was statically significant (p = 0.017) with a medium effect size of 0.28; (4) Conclusions: The postoperative posterior epiphyseal tilt was predictive factor to determine the alpha angle. However, the cut-off value of the slip angle was 16.8° for a later occurrence of a FAI type cam indicating a small range of acceptable deviations from the anatomical position for SCFE reconstruction.