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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 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.

Using cementless stems in total hip arthroplasty (THA) has revealed variable results. The risk for early aseptic loosening has been associated to certain surgical approaches and implant designs. This study determines misalignment of collared/collarless stems and the rate of subsidence using the anterolateral approach (ALA) compared to implantations via the direct lateral approach (DLA). One hundred consecutive patients underwent primary unilateral THA using the minimal invasive ALA in the lateral decubitus position and were compared to another cohort of 100 patients, treated trough the DLA. Clinical results were noted preoperatively and after 1 year using the WOMAC score. The radiographic evaluation included the stem alignment and subsidence. Overall, all patients improved in WOMAC from 48.9 points (± 11.4; 21.0–82.0) to 3.1 (± 3.2; 0.0–22.0) (p

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 2). 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.

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.

Umschriebene Knorpellasionen oder osteochondrale Defektareale des Huftgelenks betreffen haufig junge Patienten mit einem aktiven Berufs- und Privatleben. Die Ursachen fur diese Defektzonen sind vielseitig, bestimmen jedoch in einem relevanten Ausmas die therapeutischen Optionen. Neben der Domane der gelenkerhaltenden, implantatfreien Huftchirurgie stellen sog. Miniprothesen oder Teilimplantate eine weitere Behandlungsstrategie vor dem Einsatz einer Totalendoprothese (TEP) dar. Im Folgenden werden hierzu der metallische Gelenkflachenteilersatz (z. B. HemiCAP®, Arthrosurface, Franklin, MA, USA) vorgestellt und Ergebnisse aus der Literatur aufgefuhrt. Das beschriebene Verfahren wird dabei, insbesondere in Deutschland, nicht flachendeckend angeboten und durchgefuhrt, da die meisten Indikationen deckungsgleich mit denen zur Implantation einer TEP sind, welches als Routineverfahren etabliert ist. Folglich basieren die Ergebnisse aus der Literatur auf Fallserien, die der Aussagekraft der Studien und Registerdaten fur die TEP nachstehen und die dementsprechend kritischer hinterfragt werden mussen. Vom Oberflachenteilersatz ist dabei der vollstandige Oberflachenersatz („hip resurfacing“, z. B. Birmingham-Hip-Replacement, BHR, Smith and Nephew, Memphis, TN, USA) abzugrenzen, der einerseits angesichts der femoralseitigen Oberflachenrekonstruktion zwar Parallelen aufweist, bei dem es sich andererseits durch den obligaten Ersatz der azetabularen Gelenkseite jedoch definitionsgemas bereits um einen totalen Gelenkersatz handelt, der somit allenfalls eine Zwischenrolle zwischen einer schaftverankerten TEP und einem Teilersatz einnehmen kann.

The prevalence of femoroacetabular impingement syndrome in professional soccer athletes is high. Professional training and treatment conditions ensure an effective conservative therapy focusing on dynamic stability, motion control, muscle balance and core stability. In the case of persistent limitations, indication for surgery has to be considered carefully. The probability is high that return to a professional level of soccer is feasible. However, the period of rehabilitation is long, leading to a potential conflict area between economic and medical interests. Good communication and intensive patient education are essential.Die Prävalenz des femoroazetabulären Impingement-Syndroms unter professionellen Fußballspielern ist hoch. Die professionellen Trainings- und Behandlungsbedingungen stellen eine effektive konservative Therapie sicher, bei der es vor allem auf dynamische Stabilität, Bewegungskontrolle, Muskelbalance und Rumpfstabilisierung ankommt. Bei dennoch bestehenden Einschränkungen muss eine Operationsindikation sorgfältig geprüft werden. Nach einer Operation ist die Wahrscheinlichkeit hoch, dass Sport auf professionellem Niveau fortgeführt werden kann, jedoch ist die notwendige Rehabilitationsphase lang. Daraus resultiert ein Spannungsfeld zwischen wirtschaftlichen und medizinischen Interessen, in dem einer guten Kommunikation und intensiven Patientenaufklärung eine große Bedeutung zukommt.

Purpose Aim of this study was to compare the reconstruction of radiological sagittal spinopelvic parameters between lordotic (10°) and normal cages (0°) after dorsal lumbar spondylodesis. Methods This retrospective monocentric study included patients who received dorsal lumbar spondylodesis between January 2014 and December 2018. Inclusion criteria were degenerative lumbar diseases and mono- or bi-segmental fusions in the middle and lower lumbar region. Exclusion criteria were long-distance fusions (3 segments and more) and infectious and tumour-related diseases. The sagittal spinopelvine parameters (lumbar lordosis, segmental lordosis, sacral slope, pelvic incidence, and pelvic tilt) were measured pre- and post-operatively by two examiners at two different times. The patients were divided into 2 groups (group 1: lordotic cage, group 2: normal cage). Results One hundred thirty-eight patients (77 female, 61 male) with an average age of 66.6 ± 11.2 years (min.: 26, max.: 90) were included in the study based on the inclusion criteria. Ninety-two patients (66.7%) received 0° cages and 46 (33.3%) lordotic cages (10°). Segmental lordosis was increased by 4.2° on average in group 1 and by 6.5° in group 2 (p = 0.074). Average lumbar lordosis was increased by 2.1° in group 1 and by 0.6° in group 2 (p = 0.378). There was no significant difference in the correction of sagittal spinopelvic parameters. Inter- and inter-class reliability was between 0.887 and 0.956. Conclusion According to the results of our study, no advantages regarding sagittal radiological parameters for the implantation of a lordotic cage could be demonstrated.

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

IntroductionComputed tomography-based three-dimensional models may allow the accurate determination of the center of rotation, lateral and anterior femoral offsets, and the required implant size in total hip arthroplasty. In this cadaver study, the accuracy of anatomical reconstruction was evaluated using a three-dimensional planning tool.Materials and methodsA total of eight hip arthroplasties were performed on four bilateral specimens. Based on a computed tomography scan, the position and size of the prosthesis were templated with respect to the anatomical conditions.ResultsOn average, all parameters were reconstructed to an accuracy of 4.5 mm and lie within the limits recommended in the literature. All prostheses were implanted with the templated size.ConclusionsThe exact anatomy of the patient and the required size and position of the prosthesis were precisely analyzed using a templating software. Based on the present findings, the development of template-directed instrumentation is conceivable using this method. However, further technical features (e.g., navigation or robot-assisted surgery) are required for improved precision for implant positioning.

(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.

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

(1) Background: The femoroacetabular impingement (FAI) type cam leads to a conflict between the acetabular rim and a bony thickening of the femoral neck junction. While maximal excursions in flexion, adduction and internal rotation provoke pain, the aim of this study was to analyze if a cam morphology shows an impact on gait pattern. (2) Methods: Fifty-five patients with end-stage hip osteoarthritis performed gait analysis before hip replacement as well as three, six and 12 months postoperatively. Thirty-three (60%) of them presented an FAI type cam. An ANOVA was used to compare the hip angles in sagittal, frontal and transversal planes between patients with a FAI type cam (group “+cam”) and without (group “−cam”). (3) Results: Before surgery the patients of the +cam-group showed a tendency towards a reduced flexion and internal rotation at the heel strike (p &gt, 0.05). Over time, the differences were adjusted by total hip arthroplasty. (4) Conclusions: We did not find any differences in the gait analysis of patients with a FAI type cam compared to patients without.

Background We applied a previously established and validated numerical model to a novel short-stemmed implant for a ‘pre-launch’ investigation. Methods The implant system consists of two different implant geometries for valgus/varus-positioned proximal femurs with differences in volume distribution, head/neck angle, and calcar alignment. The aim of the design was to achieve a better adaption to the anatomic conditions, resulting in a favourable load transfer. The implant type G showed the best fit to our model, but both stem geometries were implanted; the implant type B was used to compute an ‘imperfection scenario’. Findings Apparent bone density decreased by 4.3% in the entire femur with the implant type G, and by 12.3% with the implant type B. Bone mass loss was pronounced in the proximal calcar region. Apparent bone density increased at the lateral cortical ring and in the minor trochanter. The apparent bone density in the imperfection scenario was very similar to that of a straight stem, indicating a distal load transfer. Interpretation No adverse effects of the A2 short-stemmed implant system on bone remodeling could be detected. The overall bone density reduction was acceptable, and wedge fixation was not observed, indicating that there was no distal load transfer. The simulation of an incongruous implant indicates the sensitivity of our model in response to modifications of implant positioning. Correct implant selection and positioning is crucial when using the A2 system.

Introduction The aim of this study was to determine number and type of failures and revisions after usage of a constrained tripolar acetabular liner in patients with high risk of dislocation. Potential correlations between these failures and the factors included were analyzed. Materials and methods In this retrospective study 55 participants in 68 cases were included after treatment with constrained tripolar acetabular liner. Patient specific data as well as surgery and implant specific data were collected. Radiological images were assessed. Furthermore, the gluteal function was analyzed. The parameters were statistically verified with regard to their influence on the failure of the constrained tripolar liner. Results This study included 16 cases (in nine participants) of postoperative failure. This results in a survival rate of 76.5% regarding the number of cases after 17 months. The statistical analysis of the different parameters considered that the number of previous surgeries has a significant (p = 0.027) influence on the failure. Conclusions This retrospective study shows that treatment with constrained tripolar acetabular liners is a satisfactory method of treatment in cases with a high risk of dislocation. However, in cases with an increasing number of previous surgeries, an increased risk of failure was found. Therefore, in such cases, this type of supply treatment should be treated critically.

Das Verstandnis der Pathologie des femoroazetabularen Impingements und ihrer Bedeutung als praarthrotische Deformitat fuhrte in der letzten Dekade zu einem rapiden Anstieg der gelenkerhaltenden operativen Eingriffe am Huftgelenk und zu einer stetigen Weiterentwicklung der operativen Techniken. Wahrend ursprunglich vor allem die recht invasive offene Huftgelenksluxation zur Anwendung kam, gewann insbesondere das Verfahren der Huftarthroskopie erheblich an Stellenwert, das jedoch technisch anspruchsvoll und mit einer ausgepragten Lernkurve behaftet ist. Um die Vorteile der besseren Darstellung und der unmittelbaren Visualisierung der Pathologie mit den Vorteilen einer geringeren Invasivitat zu verbinden, fand in den letzten 10 Jahren eine Variante des minimal-invasiven anterioren Zuganges in Form der arthroskopisch assistierten „Mini-open-Technik“ zunehmende Verbreitung, die hier vorgestellt wird.

Summary Objective Osteonecrosis of the femoral head (ONFH) is a devastating disease of the hip joint. Its early diagnosis is crucial to increase the chances of joint preserving, yet difficult due to similarities with osteoarthritis (OA) of the hip in its clinical appearance. The purpose of this study was to enhance the understanding of ONFH and its pathologic processes in contrast to OA and to identify serum biomarkers helping to improve the diagnosis of the disease. Design Bone and bone marrow samples were collected from 24 patients diagnosed with OA and 25 patients with ONFH during total hip replacement surgery. RNA was isolated, histological examination, determination of free reactive oxygen species as well as gene expression and biomarker analysis were performed. Results Histological analysis revealed differences in the structural and cellular pattern between the groups. Gene expression analysis revealed a significant upregulation for the genes ASPN, COL1A1, COL2A1 and IL6 and a significant downregulation for HIF1A in ONFH compared to OA group. Analysis of serum biomarkers showed significant differences between the groups for asporin and adiponectin. A final logistical regression model including the parameters adiponectin, asporin and HIF 1α was overall significant, explained 34.5 % of variance and classified 74.5 % of the cases correctly. Conclusion The combination of adiponectin, asporin and HIF 1α as serum biomarkers revealed a classification accuracy of 74.5 %. The information provided in this study may help to enhance the understanding of pathologic processes in ONFH and to elaborate further aspects of prediction and treatment.

Localized cartilage lesions or osteochondral defect areas of the hip joint often affect young patients with an active professional and personal live. There are multiple causes of these defect zones, but they determine the therapeutic options to some extent.In addition to the domain of joint-preserving, implant-free hip surgery, so-called mini-prostheses or partial implants represent another treatment strategy prior to the application of a total hip arthroplasty (THA). In the following, partial joint resurfacing implants (e. g., HemiCAP®, Arthrosurface, Franklin, MA, USA) are presented and results from the literature are cited. The described procedure is not widely offered, especially in Germany, because most indications are congruent with those for implantation of a THA, which is an established technique. Consequently, the results from the literature are based on case series with inferior validity compared to the studies and registry data of the THA and accordingly have to be scrutinized in a more critical way. Total surface replacement (hip resurfacing, e.g., Birmingham hip replacement, BHR, Smith and Nephew, Memphis, TN, USA) distinguish from partial surface replacement. On the one hand the BHR shows parallels with regard to the femoral surface reconstruction, but on the other hand due to the obligatory replacement of the acetabular side of the joint it meets conditions of THA, which can therefore play at best an intermediate role between a stem-anchored THA and a partial replacement.HINTERGRUND: Umschriebene Knorpelläsionen oder osteochondrale Defektareale des Hüftgelenks betreffen häufig junge Patienten mit einem aktiven Berufs- und Privatleben. Die Ursachen für diese Defektzonen sind vielseitig, bestimmen jedoch in einem relevanten Ausmaß die therapeutischen Optionen.Neben der Domäne der gelenkerhaltenden, implantatfreien Hüftchirurgie stellen sog. Miniprothesen oder Teilimplantate eine weitere Behandlungsstrategie vor dem Einsatz einer Totalendoprothese (TEP) dar. Im Folgenden werden hierzu der metallische Gelenkflächenteilersatz (z. B. HemiCAP®, Arthrosurface, Franklin, MA, USA) vorgestellt und Ergebnisse aus der Literatur aufgeführt. Das beschriebene Verfahren wird dabei, insbesondere in Deutschland, nicht flächendeckend angeboten und durchgeführt, da die meisten Indikationen deckungsgleich mit denen zur Implantation einer TEP sind, welches als Routineverfahren etabliert ist. Folglich basieren die Ergebnisse aus der Literatur auf Fallserien, die der Aussagekraft der Studien und Registerdaten für die TEP nachstehen und die dementsprechend kritischer hinterfragt werden müssen. Vom Oberflächenteilersatz ist dabei der vollständige Oberflächenersatz („hip resurfacing“, z. B. Birmingham-Hip-Replacement, BHR, Smith and Nephew, Memphis, TN, USA) abzugrenzen, der einerseits angesichts der femoralseitigen Oberflächenrekonstruktion zwar Parallelen aufweist, bei dem es sich andererseits durch den obligaten Ersatz der azetabulären Gelenkseite jedoch definitionsgemäß bereits um einen totalen Gelenkersatz handelt, der somit allenfalls eine Zwischenrolle zwischen einer schaftverankerten TEP und einem Teilersatz einnehmen kann.

Short femoral hip stems with a metaphyseal anchoring concept have been designed to treat younger patients with good bone quality. The aim of this study was to reconstruct the centre of rotation and soft tissue balancing and preserve bone in the long-term perspective. Eighteen human femurs were randomised into three groups: (1) metaphyseal anchoring short stem, (2) shortened straight stem, (3) straight stem). Prior to the implantation of the hip stems, a computed tomography (CT) of the bones was performed and the femoral ante-torsion and ante-tilt was measured and compared to the results of the post-implantation CT. This could be calculated based on the 3D coordinates taken from the pre- and post-op CT scans, which were transformed into the same coordinate systems. The mean preoperative caput–collum–diaphyseal (CCD) angle for the three groups was 126.87° ± 3.50° (Group 3: 129.64° ± 3.53°, Group 1: 123.76° ± 5.56°, Group 2: 127.53° ± 1.42°) and was consistent with published reports. The postoperative CCD angles with 126.85° ± 3.43° were within a very good reconstruction range for all three groups. The anterior offset comparison among these three groups showed significant difference in reconstruction. The smallest difference between the anatomical (preoperative) and postoperative condition was seen in Group 1 (1.47° ± 0.60°), followed by Group 2 (3.60° ± 0.23°) and Group 3 (8.00° ± 0.70°) groups. The horizontal offset showed no significant difference among the groups and was within the window of ± 5 mm. In this cadaver study, we found that the metaphyseal anchoring, partially neck-preserving short hip stem best reconstructs the ante-torsion and the ante-tilt of the femoral neck. Therefore, it can be a useful stem in younger or active middle-aged patients.

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.

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.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.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.Summarizing, the current study revealed primary metaphyseal anchorage of the METHA short stem and a metaphyseal-diaphyseal anchorage of the Bicontact stem.

Background Short stem hip prostheses have become a viable alternative for the treatment of hip osteoarthritis. In combination with minimally invasive surgery, short stem hip prostheses offer potential advantages of reduced surrounding tissue damage and faster rehabilitation. However, the limited perioperative visibility of these minimally invasive techniques may lead to reduced primary stability compared to conventional techniques. We hypothesized: a) increased migration of the minimally invasive group due to reduced primary stability and b) increased clinical scores of the minimally invasive group. Methods Sixty total hip arthroplasty patients were randomly assigned to undergo minimally invasive anterolateral modified Watson-Jones or conventional Hardinge surgery. All patients were treated with a Metha short stem prosthesis. Roentgen stereophotogrammetry and clinical scores were calculated after surgery and at 3, 6, 12, and 24 months postoperatively. Findings No statistically significant differences in implant migration and clinical scores were observed between the minimally invasive and conventional groups at any follow-up point. The largest average resultant migrations were 1.22 (SD 1.31) mm (conventional) and 1.18 (SD 1.18) mm (minimally invasive) after 24 months. The mean Harris Hip Score score improved from 54 (SD 10, conventional) and 52 (SD 13, minimally invasive) preoperatively to 97 (SD 5, both groups) after 24 months. Interpretation Overall, the differences in implant migration and clinical scores between the minimally invasive and conventional surgery groups were marginal and not clinically relevant. The data from this study suggest that good results can be expected from both the investigated approaches.

BACKGROUND A major problem associated with distraction osteogenesis is the long time required for consolidation. OBJECTIVE The goal of this study was to determine whether a percutaneous injection of recombinant human bone morphogenetic protein-2 (rhBMP-2) in a Gelfoam carrier would enhance bone consolidation following distraction. METHODS A unilateral tibial osteotomy combined with external stabilization was performed in 14 adult sheep. After a latency of four days, distraction was performed at 1.25 millimetres per day for 20 days. On days 23 and 30, the sheep received an injection of rhBMP-2/Gelfoam or buffer/Gelfoam. During the following 50 days, radiographs and in vivo torsional stiffness measurements were obtained weekly. The effect of rhBMP-2 treatment post-mortem was assessed using destructive biomechanical testing, quantitative CT and DXA analysis. RESULTS The in vivo stiffness measurements of the sheep treated with rhBMP-2 were significantly higher than those of the carrier control group (p< 0.05). These in vivo data were verified by post-mortem biomechanical testing and quantitative CT analysis. The maximum torsional moment observed was 55% greater in the sheep treated with rhBMP-2. CONCLUSIONS These data support the potential use of rhBMP-2 in an injectable carrier for enhancing consolidation, as it may ultimately lead to shorter treatment times for patients undergoing distraction procedures.

(1) Background: Preoperative templating is mainly conducted on an anteroposterior pelvic overview X-ray. For short stem hip arthroplasty, the choice of the optimal size is especially crucial to avoid complications. Thus, the study aimed to determine if there is an increased rate of correctly planned sizes using two radiological planes. (2) Methods: 50 patients with a conventional stem and 100 with a short stem total hip arthroplasty were analyzed. Without knowing the implanted size, three independent orthopedic surgeons performed digital templating: once using the anteroposterior pelvic overview only and once using the lateral view in addition. (3) Results: The rate of correctly planned sizes (+/−1 size compared to the inserted size) of templating with one plane was 86.3% ± 9.5% in short stem hip arthroplasty and 88.4% ± 6.0% in conventional stem arthroplasty. By adding the lateral view, the rate of correctly planned sizes was 89.9% ± 12.0% for the short stem hip arthroplasty group and 89.4% ± 9.8% for the conventional group (p &gt, 0.1). (4) A potential positive effect of preoperative templating using an additional lateral X-ray view for short stem implants may be suggested based on the results of this study, which did, however, not reach statistical significance.

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).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.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.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.

BACKGROUND Short-stem implants are routinely used for total hip arthroplasty in younger patients that are more likely to have secondary osteoarthritis than older patients. OBJECTIVE To investigate the applicability of short-stem hip implants for secondary osteoarthritis due to developmental dysplasia of the hip. METHODS This study analyzed the clinical and radiological results of patients with developmental dysplasia of the hip (DDH, 58 hips) and compared them to those of patients with primary osteoarthritis (POA, 59 hips) treated with the metaphyseal total hip arthroplasty (Metha®) short stem with metaphyseal fixation. RESULTS The mean clinical and radiological follow-up periods were 2.9 ± 1.1 years and 3.8 ± 1.9 years, respectively. The mean Harris Hip Score (HHS) significantly increased in both groups over this period (p< 0.0001). The caput-collum-diaphysis (CCD) angle was significantly lower in the POA group prior to surgery and significantly increased in the POA and and decreased in DDH groups, respectively. The preoperative femoral offset was lower in the DDH group and increased significantly after surgery. CONCLUSIONS The Metha® short stem in patients with DDH allows good reconstruction of joint biomechanics with a good clinical outcome.

Pre-existing or chronic pain is an established risk factor for severe postoperative pain. In this prospective observational cohort study, we investigated whether a history of chronic pain, beyond the presence of hip-related pain, affected other postoperative factors including early mobilization, function, and psychological distress after hip surgery. Patients who underwent total hip replacement surgery were observed from the preoperative day until the seventh postoperative day. Before surgery, they were characterized by their pain history, pain intensity, function, and psychological characteristics. Postoperatively, pain intensity was evaluated on day 1, 3, 5, and 7 and the analgesic consumption was recorded for each of these days. Measures of function (functional questionnaire, ability to mobilize and to climb stairs, and range of hip motion) and psychological distress were re-evaluated on day 7. A history of chronic pain was associated with slower postoperative mobilization, poorer physical function, and greater psychological distress in addition to increased postoperative pain intensity. The comorbidity of a chronic pain disorder resulted in greater pain intensity after surgery, and also impeded postoperative rehabilitation. Identification of patients with a chronic pain disorder is necessary preoperatively so that appropriate pain management and rehabilitation can be planned to facilitate recovery. Perspective Chronic pain, beyond the presence of hip-related pain, is associated with slower postoperative mobilization, poorer physical function, and greater psychological distress after total hip replacement surgery. Identification of patients with chronic pain and establishment of multiprofessional perioperative management might improve postoperative rehabilitation of patients with chronic pain.

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.

One of the problems associated with callus distraction is a long time period needed for consolidation of the newly formed bone. The goal of this study was to determine whether percutaneous injections of rhBMP 2 in αBSM would enhance bone consolidation.A unilateral tibial osteotomy combined with external stabilization was performed in 20 adult sheep. After a latency of four days, distraction was conducted for 20 days. Sheep were divided into three groups: group 1 received rhBMP-2/αBSM injections at day 23 and 30, group 2 buffer/αBSM injections at day 23 and 30 and group 3 did not receive any injection. The radiographs and in-vivo torsional stiffness measurements were obtained weekly during the following 50 days. Post-mortem bone densitometry (DXA) and mechanical testing were performed.In-vivo stiffness assessments, DXA values and the maximum torsional moment of the sheep tibia treated with two rhBMP-2 injections were not significantly greater than those of both control groups.Presented application of rhBMP-2 in αBSM failed to enhance bone consolidation in distraction osteogenesis.

The total hip arthroplasty is one of the most common artificial joint replacement procedures. Several different surface coatings have been shown to improve implant fixation by facilitating bone ingrowth and consequently enhancing the longevity of uncemented orthopaedic hip prostheses. In the present study, two different layered double hydroxides (LDHs), Mg-Fe- and Mg-Al-LDH, were investigated as potential magnesium (Mg)-containing coating materials for orthopaedic applications in comparison to Mg hydroxide (Mg(OH)2). In vitro direct cell compatibility tests were carried out using the murine fibroblast cell line NIH 3T3 and the mouse osteosarcoma cell line MG 63. The host response of bone tissue was evaluated in in vivo experiments with nine rabbits. Two cylindrical pellets (3 × 3 mm) were implanted into each femoral condyle of the left hind leg. The samples were analyzed histologically and with μ-computed tomography (μ-CT) 6 weeks after surgery. An in vitro cytotoxicity test determined that more cells grew on the LDH pellets than on the Mg(OH)2-pellets. The pH value and the Mg2+ content of the cell culture media were increased after incubation of the cells on the degradable samples. The in vivo tests demonstrated the formation of fibrous capsules around Mg(OH)2 and Mg-Fe-LDH. In contrast, the host response of the Mg-Al-LDH samples indicated that this Mg-containing biomaterial is a potential candidate for implant coating. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 525–531, 2016.

The number of primary total hip arthroplasties (THA) is steadily increasing. Over the last decade numerous so-called short stem hip arthroplasties were introduced on the market. The aim of these implants with a predominantly metaphyseal anchorage is to reduce stress shielding and thereby the risk of aseptic loosening. One of the short stem arthroplasties with predominant metaphyseal fixation is the METHA® short stem (Aesculap, Tuttlingen, Germany). In order to reconstruct the biomechanics the METHA stem is available in different sizes with different centrum-collum-diaphysis-angles (CCD-angle). In this study, we want to address the research question of how the size of the implant and different CCD-angles influence the strain patterns of the proximal femur.Three different stem sizes (size 2, 3 and 4 - CCD-angle 130°) and three stems with different CCD-angles (size 3 - 120°, 130° and 135° CCD-angle) were successively implanted in a synthetic femur. Eight strain gauges monitored the corresponding strain patterns of the proximal femur.Independent of stem size and CCD-angle only small changes in the strains were recorded around the distal part of the METHA stem when compared to the intact femur. However, all stems increased the strains in the region of the calcar. This was most pronounced by smaller CCD-angles and major sizes.The stem size and CCD-angle primarily influence the region of the calcar. Greater sizes and smaller CCD-angles lead to increased strains at the calcar. The other regions are hardly influenced by the stem size and CCDangle of the femoral component.

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®. 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. 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. 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.

Hintergrund Implantationen von Huft- und Knietotalendoprothesen sind haufig durchgefuhrte Operationen. Ein Zusammenhang zwischen hohen Operationszahlen und gutem Outcome gilt mittlerweile als erwiesen, ebenso wie ein Benefit aus Nachbehandlungsstandards. Diese Erkenntnisse werden in zertifizierten Endoprothetikzentren (EPZ) uber Qualitatsindikatoren berucksichtigt.