Very early migration of a calcar-guided short stem: a randomized study of early mobilization and the influence of a calcium phosphate coating with 60 patients.

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.

Tuberosity refixation improves functional outcome following primary reverse shoulder arthroplasty in proximal humeral fracture.

INTRODUCTION: The purpose of this prospective study was to examine clinical results of tuberosity refixation in RSA for the treatment of displaced PHF in elderly patients. We hypothesized that tuberosity refixation would increase clinical outcome. METHODS: In this prospective study, 50 patients were included after receive a primary RSA for complex proximal humeral fracture between March 2013 and December 2015 for follow-up after three, 12 and 24 months. A functional and radiological assessment was performed on the patients. RESULTS: At final follow-up after a mean period of 25.1 months, data were available for 30 women and 6 men (74% of the included overall study collective) with a mean age of 77 years (range 55-93 years) at time of surgery. The tuberosities were refixated in 74% (n = 37) and in 26% (n = 13) resected. RSA with tuberosity refixation resulted in better clinical shoulder function compared to RSA with non-refixated tuberosities. The data show an external rotation with a significant difference (24.9° vs. 14°, p < 0.05) in favor of participants with refixation. The raw CMS was statistically significant (71.3 vs. 56.3, p < 0.05) after refixation, and SSV was significant improved (82.7% vs. 68%, p < 0.05) in the same group. Among 3 of 50 patients a total of 3 complications occurred with a total of 6% surgical revision. CONCLUSIONS: In this prospective study, tuberosity refixation as part of fracture treatment using RSA results in better external rotation, subjective assessment of shoulder recovery (measured by SSV and by raw CMS) in elderly patients, compared with tuberosity excision. LEVEL OF EVIDENCE: II, Prospective comparative study.

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.

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.

The Scientific Evolution of Periacetabular Osteotomy: A Global Review.

It is well-known that hip disorders are frequently of bony origin related to an underlying pathomorphology. A fundamental understanding of morphology and biomechanics is therefore of essential importance for a targeted approach in defining treatment plans. Treatment is frequently based on altering bony morphology, for which a set of effective techniques have been proposed. Periacetabular osteotomy (PAO) allows for reorientation of the acetabulum and powerful correction of acetabular coverage. The revolutionary aspect of PAO compared to prior osteotomies lies in maintenance of the integrity of the posterior column. This allows for a substantial increase in primary stability, a larger bony surface for healing, and simple reorientation of the acetabular fragment that is free of posterior ligamentous restraints. The results for dysplasia are very promising. Indications have been refined by studies revealing that the presence of degenerative changes and age > 40 years at the time of surgery represent prognostic factors of poorer outcome. Indications have also been broadened to include acetabular retroversion (with posterolateral dysplasia) and borderline hip dysplasia. A glimpse at the future would reflect major advances related to individual planning, surgical training, and precise surgical conduction. In the era of digitalization, augmented reality may assist in performing bony cuts and act as an aid for some of the blind ischial and retro-acetabular cuts. Innovations in perioperative management will enhance recovery after the procedure and allow for early recovery programs with optimized protocols of pain management. Considering that the success of PAO in the young is comparable to the success of hip arthroplasty in the old, PAO should be considered one of the pillars of modern orthopedic surgery.

Clinical results after open gluteus medius repair in single-row technique.

PURPOSE: The aim of this retrospective study is to present the clinical results of open repair of gluteus medius and gluteus minimus tendon tears using the single-row suture anchor technique. METHODS: This retrospective study included 43 participants after open repair of the abductor tendon of the hip joint using a single-row suture anchor technique. Clinical outcome parameters were assessed by VAS (0-10), gait safety (1 = absolutely safe gait without assistive devices - 10 = gait not possible), SHV (0-100%), mHHS, WOMAC, and gluteal muscle strength status from single-leg stance and against gravity. RESULTS: Thirty-two female and 11 male subjects with an average age of 65.2 years were included in this study. Overall, a significant decrease in pain (VAS 3.2) and improvement in joint function is observed after a period of 22.3 months. The mHHS reached 61.9 points, WOMAC 28.2, SHV 69.8% and gait stability measured by the VAS reached 3.4. 58.1% of the participants reported not having Trendelenburg, while 4% could not control the single leg stance. CONCLUSIONS: The present study shows that single row repair for open glutueus medius refixation indicates limited clinical results. Although there was an improvement in clinical outcome. The majority of subjects continued to report limiting symptoms.

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.

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.

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.

Which anatomical conditions are associated with limitations of the hip function after SCFE?

BACKGROUND: Patients sustained a slipped capital femoral epiphysis (SCFE) might have symptoms beyond their stabilization surgery in the childhood. METHODS: 35 patients with a SCFE were treated in our clinic and available for a clinical follow-up. The results were compared in dependence of the presence of dysplasia, acetabular retroversion or a FAI type CAM. RESULTS: A FAI type CAM led to significant inferior results (p < 0.05), especially in combination with a retroversion. CONCLUSIONS: The clinical outcome seemed to be influenced by the presence of a FAI type CAM or a combination with a retroversion, which might aggravate the femoro-acetabular conflict. LEVEL OF EVIDENCE: III, retrospective.

A gifted SNARC? Directional spatial-numerical associations in gifted children with high-level math skills do not differ from controls.

The SNARC (Spatial-Numerical Association of Response Codes) effect (i.e., a tendency to associate small/large magnitude numbers with the left/right hand side) is prevalent across the whole lifespan. Because the ability to relate numbers to space has been viewed as a cornerstone in the development of mathematical skills, the relationship between the SNARC effect and math skills has been frequently examined. The results remain largely inconsistent. Studies testing groups of people with very low or very high skill levels in math sometimes found relationships between SNARC and math skills. So far, however, studies testing such extreme math skills level groups were mostly investigating the SNARC effect in individuals revealing math difficulties. Groups with above average math skills remain understudied, especially in regard to children. Here, we investigate the SNARC effect in gifted children, as compared to normally developing children (overall n = 165). Frequentist and Bayesian analysis suggested that the groups did not differ from each other in the SNARC effect. These results are the first to provide evidence for the SNARC effect in a relatively large sample of gifted (and mathematically highly skilled) children. In sum, our study provides another piece of evidence for no direct link between the SNARC effect and mathematical ability in childhood.

Clinical and radiographic outcomes with the Nanos™ short-stem hip implant at 24 months: A prospective, single-center study.

AIM: Short-stem total hip arthroplasty is designed to preserve proximal bone stock in case of eventual revision, potentially benefiting younger and more active patients. This prospective, single-center study assessed the safety and performance of the partially neck-sparing Nanos™ short-stem uncemented prosthesis at 24 months using clinical outcome scores and radiographic results. METHODS: Between April 2011 and February 2015, 52 subjects (mean age, 54.9 years) underwent total hip arthroplasty and were followed up at 3, 6, 12 and 24 months. The primary outcome was improvement in quality of life as measured by the Short-Form 36 Mental Component Score (SF-36 MCS). Secondary clinical outcomes included the Harris Hip Score, Hip Disability and Osteoarthritis Outcome Score, Postel Merle d'Aubigné-Score, Activity Level University of California, Los Angeles score, and Pain Visual Analogue Scale. Complications and radiographic images were also recorded at each follow-up. RESULTS: Mean SF-36 MCS score significantly improved from baseline to final follow up at 24 months (61.3 vs. 79.5, respectively; p < 0.001). All secondary clinical outcomes also showed significant improvement (p < 0.001) during this time period. Neutral stem positioning was achieved in 45 subjects (86.5%). Two subjects (3.8%) underwent revisions: one for a periprosthetic fracture unrelated to the study device and another due to a prosthetic joint infection. Intraoperatively, one fissure fracture of the acetabulum occurred. CONCLUSION: Total hip arthroplasty with the Nanos short-stem led to significant clinical improvements and a high subjective satisfaction rate at 24 months. Further follow-up will determine whether these effects are sustained in the long term.

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.

Allogenic bone graft for femoral defect augmentation in hip revision arthroplasty: A case series.

Cortical bone loss in revision hip arthroplasty requires an adequate stabilization to achieve a durable implant fixation. This case series shall illustrate possible indications for the use of allogenic grafts in revision hip arthroplasty. Twelve patients with femoral bone loss were treated with allografts. In addition to established clinical scores, the radiological follow-ups were analyzed for hints of implants loosening and the osteointegration of the allografts. After a mean follow-up of 3.0 years the mHHS was 61.3 points and the UCLA 3.8. One patient showed a non-progressive radiolucency around the hip implant. The osteointegration of all allogenic grafts happened on time. Up to the last follow-up no revision surgery of the hip implants and the associated femoral bone graft was observed. Allogenic bone grafts present a method for biological stabilization in situations of large femoral cortical bone defects in revision hip arthroplasty.

Deformable image registration for adaptive radiotherapy with guaranteed local rigidity constraints.

BACKGROUND: Deformable image registration (DIR) is a key component in many radiotherapy applications. However, often resulting deformations are not satisfying, since varying deformation properties of different anatomical regions are not considered. To improve the plausibility of DIR in adaptive radiotherapy in the male pelvic area, this work integrates a local rigidity deformation model into a DIR algorithm. METHODS: A DIR framework is extended by constraints, enforcing locally rigid deformation behavior for arbitrary delineated structures. The approach restricts those structures to rigid deformations, while surrounding tissue is still allowed to deform elastically. The algorithm is tested on ten CT/CBCT male pelvis datasets with active rigidity constraints on bones and prostate and compared to the Varian SmartAdapt deformable registration (VSA) on delineations of bladder, prostate and bones. RESULTS: The approach with no rigid structures (REG0) obtains an average dice similarity coefficient (DSC) of 0.87 ± 0.06 and a Hausdorff-Distance (HD) of 8.74 ± 5.95 mm. The new approach with rigid bones (REG1) yields a DSC of 0.87 ± 0.07, HD 8.91 ± 5.89 mm. Rigid deformation of bones and prostate (REG2) obtains 0.87 ± 0.06, HD 8.73 ± 6.01 mm, while VSA yields a DSC of 0.86 ± 0.07, HD 10.22 ± 6.62 mm. No deformation grid foldings are observed for REG0 and REG1 in 7 of 10 cases; for REG2 in 8 of 10 cases, with no grid foldings in prostate, an average of 0.08 % in bladder (REG2: no foldings) and 0.01 % inside the body contour. VSA exhibits grid foldings in each case, with an average percentage of 1.81 % for prostate, 1.74 % for bladder and 0.12 % for the body contour. While REG1 and REG2 keep bones rigid, elastic bone deformations are observed with REG0 and VSA. An average runtime of 26.2 s was achieved with REG1; 31.1 s with REG2, compared to 10.5 s with REG0 and 10.7 s with VMS. CONCLUSIONS: With accuracy in the range of VSA, the new approach with constraints delivers physically more plausible deformations in the pelvic area with guaranteed rigidity of arbitrary structures. Although the algorithm uses an advanced deformation model, clinically feasible runtimes are achieved.