[Treatment options for femoroacetabular impingement syndrome and osteoarthritis]. / Behandlungsoptionen bei femoroazetabulärem Impingement-Syndrom und Koxarthrose.

Femoroacetabular impingement syndrome (FAIS) is a prearthritic deformity. Many patients with FAIS show signs of osteoarthritis at the time of initial presentation. Ideally, surgical correction of FAIS should stop the progression of osteoarthritis. However, biological changes in the joint, inflammatory processes, and patient-specific factors, which are not influenced by surgery, show a role in the progression of joint degeneration. Thus, it is not surprising that the results of joint-preserving surgery in FAIS and osteoarthritis Tönnis grade 2 and higher are bad, and patients often need to undergo total hip replacement (THR).Even in patients with initial osteoarthritis (Tönnis grade 1) the results of joint-preserving surgery are significantly worse in comparison to in patients without osteoarthritis. As this pathology occurs mainly in young patients, efforts should be made to avoid THR, as the risk of loosening and revision surgery is increased. Analysis of risk factors that lead to worse outcome in joint-preserving surgery can be helpful. Age > 45 years, adiposity, high alpha angle, CE angle < 25° and female sex are risk factors that lead to worse outcome in patients with risk factors and osteoarthritis Tönnis grade 1, the success rate of joint-preserving surgery after 5 years is below 50%. Therefore, we recommend non-surgical treatment. Promising is the use of mesenchymal progenitor cells (MPCs), even if their routine use has not been established. If conservative therapy is not successful, THR is indicated. With the use of modern bearings, a survival rate of THR of more than 90% after 15 years is reported in patients < 50 years. Patient satisfaction after THR is higher than after joint-preserving surgery.The combination of treatment modalities like joint-preserving surgery in combination with the application of MPCs to both correct the mechanical conflict and also influence progression of osteoarthritis is promising the from a biological point of view.

Stimulation of human bone marrow mesenchymal stem cells by electromagnetic transduction therapy - EMTT.

Many different pulsed electromagnetic field (PEMF) devises have been clinically used to stimulate healing processes, but many procedures are still without supporting basic research data. The aim of this study was to investigate a new modified pulsed electromagnetic field therapy: electromagnetic transduction therapy (EMTT). EMTT is technically based on high-intensive PEMFs with a magnetic field strength between 80 and 150 mT. The effect of EMTT for a 10-min session three times a week on human bone marrow mesenchymal stem cells (MSCs) was evaluated by assessing cell viability, gene expression of bone regenerative factors and VEGF-A (vascular endothelial growth factor) secretion after 7 and 14 days of treatment. No negative or toxic effects of EMTT on MSCs in vitro were observed in the applied test frame. The VEGF-ELISA at day 7 of EMTT treatment with 80 mT showed a significant higher VEGF concentration compared to untreated control group. In conclusion, high-intensive electromagnetic impulses showed no harmful effects on MSC cultures in our study. The enhancement of the proangiogenic factor VEGF in MSCs on day 7 indicates a substantial role in cell-stimulating effect of EMTT. Further in vitro and in vivo studies should differentiate specific stimulating and regenerating effects of EMTT impulses in soft tissue engineering. Specific electromagnetic characteristics have to be determined to optimize electromagnetic treatment options in orthopedic surgery and traumatology and soft tissue treatment options.

[Surgical treatment of femoroacetabular impingement syndrome : Arthroscopy-mini-open-surgical hip dislocation]. / Auswahl des Operationsverfahrens beim Femoroazetabulären Impingement-Syndrom : Arthroskopie ­ "mini-open" ­ chirurgische Hüftluxation.

BACKGROUND: Femoroacetabular impingement syndrome (FAIS) is one of the most common prearthritic hip deformities. Since FAIS is a mechanical pathology, surgical correction of the underlying deformity is the sole causal treatment. If surgery is indicated, a surgical technique that results in complete deformity correction with least morbidity should be selected. ARTHROSCOPY: Due to advancements in techniques and instruments, most pathologies in FAIS can nowadays be addressed arthroscopically. Hip arthroscopy can be successfully performed if the locations of the pathologies are anterior and lateral. MINI-OPEN APPROACH: In special cases and indications-like periarticular pathologies, pathologies of the hip capsule and large labral reconstructions and transplantations, a combination of arthroscopy with a mini-open approach is advantageous. Furthermore, the learning curve of hip arthroscopy can be improved with an additional open approach. SURGICAL HIP DISLOCATION: Global and circumferential pathologies still have to be addressed in surgical hip dislocation to avoid residual deformities. Finally, extraarticular osteotomies have to be considered in cases with significant rotational deformities.

Autologous Chondrocyte Transplantation in Femoroacetabular Impingement Syndrome: Growth and Redifferentiation Potential of Chondrocytes Harvested from the Femur in Cam-Type Deformities.

OBJECTIVE: Cam-type femoroacetabular impingement (FAI) syndrome is one of the most frequent reasons for cartilage damage in the hip. Autologous chondrocyte transplantation has proven high success rates in the treatment of focal chondral defects; however, harvesting of chondrocytes in the hip has been reported but not specifically from the region of femoral cam lesions. Therefore, the goal of this study was to analyze the growth and redifferentiation potential of cartilage samples harvested from the cam deformities in patients with FAI. DESIGN: Cartilage samples were gained from 15 patients with cam-type FAI undergoing arthroscopic femoral cam resection. Healthy (hyaline cartilage of the hip and knee joint, n = 12) and arthritic control groups (degenerative changes in cartilage of the hip joint, n = 8) were also analyzed. Chondrocytes were initially cultured under monolayer, and subsequently under pellet conditions. A comparative representation of the groups was performed by Mankin score classification, immunohistochemistry (IHC) (Col1, Col2, aggrecan), and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) (Col1, Col2, Col10, Sox9, RunX2). RESULTS: Mankin score of FAI-samples (4.1±3.1, Range 0-10) showed a wide variation but was significant lower (P = 0.0244) when compared with the arthritic control (7.5 ± 2.7, range 4-12). IHC showed an increased deposition of Col2 (P = 0.0002) and aggrecan (P = 0.0261) after pellet culture compared with deposition after monolayer culture in all groups. In qRT-PCR, FAI samples showed after pellet culture increased Col2 (P = 0.0050) and Col10 expression (P = 0.0006) and also Mankin score correlated increasing gene-expression of Col10 (r = 0.8108, P = 0.0341) and RunX2 (r = 0.8829, P = 0.123). CONCLUSIONS: Cartilage samples of patients with cam-type FAI showed sufficient but heterogeneous composition relating to histological quality and chondrogenic potential. However, harvesting of chondrocytes from the cam lesion might be a valid option especially if a cartilage lesion is noted in a diagnostic arthroscopy and individual preexisting stage of cartilage degeneration and appropriate pellet-culturing conditions are considered.

[The minimally invasive AMIS technique for total hip replacement : Video article]. / Die minimal-invasive AMIS-Technik zur Implantation von Hüftprothesen : Videobeitrag.

OBJECTIVE OF THE SURGERY: Minimally-invasive implantation of a total hip arthroplasty without damage to or incision of muscles. INDICATIONS: Osteoarthritis, femoral neck fracture, general indications for total hip arthroplasty. CONTRAINDICATIONS: Contraindications for hip arthroplasty. SURGICAL TECHNIQUE: The surgical technique is demonstrated in detail with the help of a video of the surgical procedure, which is available online: positioning on a fracture table with a special leg holder, anterior approach between tensor fasciae latae and rectus femoris muscle, incision of hip capsule and capsular protection, osteotomy of femoral neck in situ, removal of femoral head and acetabular reaming, minimally invasive implantation of acetabular cup, release of pubofemoral ligament and-if necessary-ischiofemoral ligament, external rotation and hyperextension in leg holder with elevation of the proximal femur by a hypomochlion, femoral preparation and implantation of femoral implant, reposition, capsular suture, wound closure. FOLLOW-UP: Weight-bearing as tolerated, free movement without limitation of range of motion. EVIDENCE: Randomized trials and systematic reviews report faster rehabilitation with early mobilization, within the first 3 months after surgery; less postoperative pain, less muscle damage and shorter hospital stay; older patients benefit from reduced morbidity and mortality.

How to address ischiofemoral impingement? Treatment algorithm and review of the literature.

Ischiofemoral impingement (IFI) is a rare cause of hip pain defined by a narrowing of the space between the lateral aspect of the os ischium and the lesser trochanter of the femur. Several underlying anatomic, functional and iatrogenic pathologies have been identified for symptomatic IFI in native hip joints and after total hip arthroplasty. Clinical symptoms vary but most commonly consist of pain of the lower buttock and groin including the inner thigh, and a snapping or clunking phenomenon is often reported. Symptoms may be provoked by a combined extension, adduction and external rotation during physical examination and during long-stride walking. Radiographs of the pelvis and an axial or false-profile-view of the hip as well as magnetic resonance imaging (MRI)-scans should be obtained to strengthen the diagnosis. On MRI, the quadratus femoris muscle signal and the space confined by the anatomic structures surrounding the muscle, the quadratus femoris space, are to be assessed. Targeted infiltration of the muscle can be helpful both diagnostically and therapeutically. The literature on differential diagnoses and treatment options for IFI is limited; therapeutic suggestions are offered only in case reports and series. With this work, we aim to give a systematic approach to the non-surgical and surgical treatment options for IFI based upon the current literature and the authors' personal experience.

[Biologic Reconstruction of Full Sized Cartilage Defects of the Hip: A Guideline from the DGOU Group "Clinical Tissue Regeneration" and the Hip Committee of the AGA]. / Biologische Rekonstruktion lokalisiert vollschichtiger Knorpelschäden des Hüftgelenks: Empfehlungen der Arbeitsgemeinschaft "Klinische Geweberegeneration" der DGOU und des Hüftkomitees der AGA.

Background Symptomatic pre-arthritic deformities such as femoroacetabular impingement (FAI) or hip dysplasia often lead to localised cartilage defects and subsequently to osteoarthritis. The present review of the working group "Clinical Tissue Regeneration" of the German Society of Orthopaedics and Trauma (DGOU) and the hip committee of the AGA (German speaking Society for Arthroscopy and Joint Surgery) provides an overview of current knowledge of the diagnosis and surgical treatment of cartilage defects, in order to infer appropriate therapy recommendations for the hip. Methods Review of FAI and resultant cartilage damage in the hip as reported in published study findings in the literature and discussion of the advantages and disadvantages of different surgical procedures to preserve the joint. Results Most published studies on the surgical treatment of cartilage damage in the hip report defects caused by cam-type FAI at the acetabulum. Development of these defects can be prevented by timely elimination of the relevant deformities. At present, current full-thickness cartilage defects are mostly treated with bone marrow-stimulating techniques such as microfracture (MFx), with or without a biomaterial, and matrix-assisted autologous chondrocyte transplantation (MACT). Osteochondral autologous transplantation (OAT) is not the treatment of choice for isolated full-thickness chondral defects at the hip, because of the unfavourable risk-benefit profile. Due to the relatively short history of cartilage repair surgery on the hip, the studies available on these procedures have low levels of evidence. However, it is already becoming obvious that the experience gained with the same procedures on the knee can be applied to the hip as well. For example, limited healing and regeneration of chondral defects after MFx can also be observed at the hip joint. Conclusions The cartilage surface of the acetabulum, where FAI-related chondral lesions appear, is considerably smaller than the weight-bearing cartilage surface of the knee joint. However, as in the knee joint, MACT is the therapy of choice for full-thickness cartilage defects of more than 1.5 - 2 cm2. Minimally invasive types of MACT (e.g. injectable chondrocyte implants) should be preferred in the hip joint. In cases where a single-stage procedure is indicated or there are other compelling reasons for not performing a MACT, a bone marrow-stimulating technique in combination with a biomaterial covering is preferable to standard MFx. For treatment of lesions smaller than 1.5 - 2 cm2 the indication for a single-stage procedure is wider. As with defects in the knee, it is not possible to determine a definite upper age limit for joint-preserving surgery or MACT in the hip, as the chronological age of patients does not necessarily correlate with their biological age or the condition of their joints. Advanced osteoarthritis of the hip is a contraindication for any kind of hip-preserving surgery. Long-term observations and prospective randomised studies like those carried out for other joints are necessary.

19 years outcome after cementless total hip arthroplasty with spongy metal structured implants in patients younger than 65 years.

BACKGROUND: Cementless fixation of total hip arthroplasties (THAs) is often favored in young, high-demanding patients due to the conservation of valuable bone-stock and easier revision if loosening has occurred. Long-term outcome data of the spongy metal structured implant used in the present study in patients younger than 65 years are still lacking. METHODS: We conducted a retrospective chart review and functional investigation (Merle d'Aubigné score, SF-12) of patients younger than 65 years at implantation treated with a spongy metal structured THA (n = 79) from one orthopedic university center from 1985 to 1989. RESULTS: At a 19-year mean follow-up (range: 15.3 - 21.3 years), the overall stem survival rate was 93.7 %, and the overall cup survival rate was 82.3 %. Revision surgeries of the stem were performed in all cases for aseptic loosening at an average of 15.3 ± 3.5 years after implantation. Acetabular components were revised for aseptic loosening and recurrent dislocation after inlay revision on an average of 11.8 ± 4.7 years after implantation. No other device related complications occurred within the 19-year follow-up period. No correlation was found between time of revision and gender or age. Clinical outcome scores (Merle d'Aubigné score, SF-12) revealed excellent to good results of the implanted THAs in 87 % of patients. CONCLUSIONS: We conclude that spongy metal structured cementless THAs implanted in young patients have an excellent survival and provide trustworthy clinical results at 19 years of follow-up.

A new model of implant-related osteomyelitis in the metaphysis of rat tibiae.

BACKGROUND: Animal models serve as an important tool to understand peri-implant infection. Most of the models use high bacterial loads (>10(4) colony forming units, CFU) to provide high infection rates. Therefore these animals evolve rather similarly, making comparison between groups and statistical analysis possible. On the other hand, to mimic clinical constellation of surgery-related infections the use of low amounts of bacteria would be more advantageous. METHODS: We developed a metaphyseal rat model of peri-implant bone infection with low amount of bacterial loads (10(2) and 10(3) CFU of Staphylococcus aureus) and investigated osseointegration of the implants coated with hydroxyapatite (HA) and low-dosed HA-silver (HA-Ag). Non-infected implants served as controls. After 6 weeks rats were sacrificed and implants evaluated for osseointegration and infection. RESULTS: Infection of implanted devices was reliably induced, independently whether 10(2) or 10(3) CFU of S. aureus were inoculated and HA or HA-Ag coated implants were used. No systemic infection was present in any of the animals at the time of sacrifice, and no animal developed acute infection requiring premature sacrifice. All CFU counts of the implant and the bone at sacrifice were significantly higher than the inoculated load (p < .05). All sterilely inserted implants showed excellent osseointegration and no infection. CONCLUSIONS: Our present study of a rat tibia model reliably induced osteomyelitis in the metaphysis with low-doses of bacteria. The addition of low-dosed Ag to the implant coating was not able to reduce the infection rates. The results demonstrate that it is possible to develop a model of implant-related osteomyelitis in rats with low amounts of bacteria to better mimic clinical constellations. No other promoters of infection besides insertion of the screw implant were used in this model.

Current evidence of extracorporeal shock wave therapy in chronic Achilles tendinopathy.

Chronic Achilles tendinopathy has been described as the most common overuse injury in sports medicine. Several treatment modalities such as activity modification, heel lifts, arch supports, stretching exercises, nonsteroidal anti-inflammatories, and eccentric loading are known as standard treatment mostly without proven evidence. After failed conservative therapy, invasive treatment may be considered. Extracorporeal shock wave therapy (ESWT) has been successfully used in soft-tissue pathologies like lateral epicondylitis, plantar fasciitis, tendinopathy of the shoulder and also in bone and skin disorders. Conclusive evidence recommending ESWT as a treatment for Achilles tendinopathy is still lacking. In plantar fasciitis as well as in calcific shoulder tendinopathy shock wave therapy is recently the best evaluated treatment option. This article analysis the evidence based literature of ESWT in chronic Achilles tendinopathy. Recently published data have shown the efficacy of focused and radial extracorporeal shock wave therapy.

Clinically relevant effectiveness of focused extracorporeal shock wave therapy in the treatment of chronic plantar fasciitis: a randomized, controlled multicenter study.

BACKGROUND: The effectiveness of extracorporeal shock wave therapy in the treatment of plantar fasciitis is controversial. The objective of the present study was to test whether focused extracorporeal shock wave therapy is effective in relieving chronic heel pain diagnosed as plantar fasciitis. METHODS: Two hundred and fifty subjects were enrolled in a prospective, multicenter, double-blind, randomized, and placebo-controlled U.S. Food and Drug Administration trial. Subjects were randomized to focused extracorporeal shock wave therapy (0.25 mJ/mm(2)) or placebo intervention, with three sessions of 2000 impulses in weekly intervals. Primary outcomes were both the percentage change of heel pain on the visual analog scale composite score (pain during first steps in the morning, pain with daily activities, and pain with a force meter) and the Roles and Maudsley score at twelve weeks after the last intervention compared with the scores at baseline. RESULTS: Two hundred and forty-six patients (98.4%) were available for intention-to-treat analysis at the twelve-week follow-up. With regard to the first primary end point, the visual analog scale composite score, there was a significant difference (p = 0.0027, one-sided) in the reduction of heel pain in the extracorporeal shock wave therapy group (69.2%) compared with the placebo therapy group (34.5%). Extracorporeal shock wave therapy was also significantly superior to the placebo therapy for the Roles and Maudsley score (p = 0.0006, one-sided). Temporary pain and swelling during and after treatment were the only device-related adverse events observed. CONCLUSIONS: The results of the present study provide proof of the clinically relevant effect size of focused extracorporeal shock wave therapy without local anesthesia in the treatment of recalcitrant plantar fasciitis, with success rates between 50% and 65%. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Patients with intolerance reactions to total knee replacement: combined assessment of allergy diagnostics, periprosthetic histology, and peri-implant cytokine expression pattern.

We performed a combined approach to identify suspected allergy to knee arthroplasty (TKR): patch test (PT), lymphocyte transformation test (LTT), histopathology (overall grading; T- and B-lymphocytes, macrophages, and neutrophils), and semiquantitative Real-time-PCR-based periprosthetic inflammatory mediator analysis (IFNγ, TNFα, IL1-ß, IL-2, IL-6, IL-8, IL-10, IL17, and TGFß). We analyzed 25 TKR patients with yet unexplained complications like pain, effusion, and reduced range of motion. They consisted of 20 patients with proven metal sensitization (11 with PT reactions; 9 with only LTT reactivity). Control specimens were from 5 complicated TKR patients without metal sensitization, 12 OA patients before arthroplasty, and 8 PT patients without arthroplasty. Lymphocytic infiltrates were seen and fibrotic (Type IV membrane) tissue response was most frequent in the metal sensitive patients, for example, in 81% of the PT positive patients. The latter also had marked periprosthetic IFNγ expression. 8/9 patients with revision surgery using Ti-coated/oxinium based implants reported symptom relief. Our findings demonstrate that combining allergy diagnostics with histopathology and periprosthetic cytokine assessment could allow us to design better diagnostic strategies.

Percutaneous epidural lysis of adhesions in chronic lumbar radicular pain: a randomized, double-blind, placebo-controlled trial.

BACKGROUND: Chronic radicular pain can occur after disc pathology and failed back surgery. An evidence-based effective therapeutic option is not available nor does a gold standard exist. OBJECTIVES: A randomized controlled trial to analyze the clinical efficacy of percutaneous epidural lysis of adhesions in chronic radicular pain. STUDY DESIGN: Prospective randomized placebo controlled interventional trial. Power calculation based on a feasibility trial. SETTING: Medical university centers. METHODS: Within 4 years a total of 381 patients with chronic radicular pain lasting longer than 4 months which failed to respond to conservative treatments were screened and 90 patients were enrolled. They were randomly assigned to receive either percutaneous neurolysis or placebo with concealed allocation in permuted blocks of 4 to 8, stratified by treatment center. The primary outcome measure was the differences in percent change of Oswestry Disability Index (ODI) scores 3 months after intervention. Secondary outcome measures were difference in percent change of ODI scores and Visual Analog Scale (VAS) 6 and 12 months after intervention and success rates defined as at least 50% reduction in ODI scores and VAS scores (mean change from baseline) at 3, 6, and 12 months after treatment. Explorative, 2-sided group comparisons for baseline characteristics between active treatment and controls were done using the t-test for 2 independent samples for quantitative data and Fisher's exact test for binary data. RESULTS: The ODI and VAS scores as well as the success rates for ODI vs VAS were significantly better 3, 6, and 12 months in the lysis group vs the control group. The ODI in the lysis group improved from 55.3 ± 11.6 to 26.4 ± 10.8 after 3 months. The placebo group improved from 55.4 ± 11.5 to 41.8 ± 14.6 (P < 0.01). VAS improved from 6.7 ± 1.1 to 2.9 ± 1.9 in the active group and from 6.7 ± 1.1 to 4.8 ± 2.2 (P < 0.01) after placebo. Twelve month follow-up shows further improvement, the differences remain significant. In multiple linear regression, forward and backward variable selection methods resulted in the same covariate model confirming the univariate result for group comparison in the primary analysis. No severe side effects occurred but minor transient neurological effects such as partial sensomotoric deficits did. One dura puncture and one catheter displacement were found. LIMITATIONS: Specific effects of single treatment components cannot be specified because there was no imaging examination after treatment. CONCLUSION: Based on the findings of our study as well as other studies, we believe the minimally invasive percutaneous adhesiolysis procedure should be the first choice treatment option for patients with chronic lumbosacral radicular pain who present with clinical history and findings similar to those of the patients enrolled in our study.

Antimicrobial peptides and proinflammatory cytokines in periprosthetic joint infection.

BACKGROUND: Differentiation between septic and aseptic loosening of joint replacements is essential for successful revision surgery, but reliable markers for the diagnosis of low-grade infection are lacking. The present study was performed to assess intra-articular and systemic levels of antimicrobial peptides and proinflammatory cytokines as diagnostic markers for periprosthetic joint infection. METHODS: Fifteen consecutive patients with staphylococcal periprosthetic joint infections and twenty control patients with aseptic loosening of total hip and knee replacements were included in this prospective, single-center, controlled clinical trial. Expression of the antimicrobial peptides human ß-defensin-2 (HBD-2), human ß-defensin-3 (HBD-3), and cathelicidin LL-37 (LL-37) was determined by ELISA (enzyme-linked immunosorbent assay) in serum and joint aspirates. Proinflammatory cytokines were assessed in serum and joint aspirates with use of cytometric bead arrays. C-reactive protein in serum, microbiology, and histopathology of periprosthetic tissue served as the "gold standard" for the diagnosis of infection. RESULTS: The antimicrobial peptides HBD-3 and LL-37 were significantly elevated in joint aspirates from patients with periprosthetic joint infection compared with patients with aseptic loosening, and the area under the curve (AUC) in a receiver operating characteristic curve analysis was equal to 0.745 and 0.875, respectively. Additionally, significant local increases in the proinflammatory cytokines interleukin (IL)-1ß, IL-4, IL-6, IL-17A, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α were observed to be associated with infection. Logistic regression analysis indicated that the combination of an antimicrobial peptide with another synovial fluid biomarker improved diagnostic accuracy; the AUC value was 0.916 for LL-37 and IL-4, 0.895 for LL-37 and IL-6, 0.972 for HBD-3 and IL-4, and 0.849 for HBD-3 and IL-6. In contrast, the only antimicrobial peptides and cytokines in serum that showed a significant systemic increase in association with infection were HBD-2, IL-4, and IL-6 (all of which had an AUC value of <0.75). CONCLUSIONS: The present study showed promising results for the use of antimicrobial peptides and other biomarkers in synovial fluid for the diagnosis of periprosthetic joint infection, and analysis of the levels in synovial fluid was more accurate than analysis of serum.

Incidence and outcome after infection of megaprostheses.

Recent advances in chemotherapy and radiation therapy in the treatment of malignant bone tumours as well as the consistent increase of revision arthroplasties have been followed by an increased use of megaprostheses. These large foreign bodies make infection a common and feared complication. Infection rates of 3 - 31% have been reported (average approx. 15%), often in conjunction with risk factors, e.g. the anatomic region (pelvis implants in particular), implant alloy, and underlying reason for implantation of a megaprosthesis. Apart from the basic principles of septic revision arthroplasty, special patient and implant factors have to be considered in infected megaprosthesis, which we have summarised in our paper (e.g. life expectancy, implant design, spacers and external stabilisation). This article further analyses the current literature available for these cases and summarises outcome after treatment of periprosthetic infections.

Total hip replacement in developmental dysplasia using an oval-shaped cementless press-fit cup.

PURPOSE: Acetabular roof deficiency due to subluxation of the femoral head (Hartofilakidis type II) increases the complexity of total hip arthroplasty. In these cases some form of support is usually required, to reach stable fixation of the acetabular component. Pursuing this aim, the oval-shaped cementless cranial socket could be an alternative to conventional treatment options. METHODS: Between 1998 and 2008, 37 patients (40 hips) underwent primary total hip arthroplasty using the cranial socket (mean follow-up 5.6 years, range 26 to 133 months). In a retrospective study we compared these clinical and radiological results with the results of a matched control group consisting of 35 patients (40 hips) treated with a standard cementless hemispherical cup in combination with bulk femoral autografting (mean follow-up 6.9 years, range 30 to 151 months). RESULTS: There were no statistically significant differences in the HHS (p=0.205) or the SF-36 (p=0.26) between both groups. There was no prosthesis failure due to septic or aseptic loosening. Time of surgery was significantly shorter in the cranial socket group (p<0.001). The acetabular component could be placed in the ideal rotational hip centre in 24 (60%) hips in the cranial socket group and 32 (80%) hips in the control group, respectively. CONCLUSIONS: Our study indicates, that the cranial socket can be an alternative treatment option for the reconstruction of acetabular deficiency in osteoarthritis secondary to developmental dysplasia.

The epiphyseal torsion angle in MR arthrography of the hip: diagnostic utility in patients with femoroacetabular impingement syndrome.

OBJECTIVE: The purpose of the study was to evaluate whether patients with clinically suspected femoroacetabular impingement (FAI) show higher epiphyseal torsion angle values on MR arthrography than healthy volunteers. Another objective was to estimate whether patients with increased epiphyseal torsion angles show a higher incidence of hip abnormalities or a higher incidence of increased alpha angles on MR arthrography than patients with an epiphyseal torsion angle considered normal. MATERIALS AND METHODS: Sixty-eight consecutive patients with clinically suspected FAI, no history of hip surgery, and MR arthrography of the hip performed at our institution were included in the study group. The control group included 50 standard MR examinations of the hip of 25 healthy volunteers with negative findings on a clinical impingement test. Epiphyseal torsion angles and alpha angles were measured independently by three radiologists. Furthermore, MR arthrograms were retrospectively evaluated by two radiologists in consensus for hip abnormalities associated with FAI. RESULTS: The epiphyseal torsion angles were significantly higher in the study group than the control group for all three readers (reader 1, p = 0.001; reader 2, p = 0.003; reader 3, p = 0.045). There was no statistical correlation between increased epiphyseal torsion angles and pathologic alpha angles (readers 1-3: p = 0.199, p = 0.343, p = 0.058, respectively). Patients with increased epiphyseal torsion angles did not show a higher incidence of labral abnormalities than patients with epiphyseal torsion angles considered normal (readers 1-3: p = 0.335, p = 0.383, p = 0.676). CONCLUSION: Patients with clinically suspected FAI show increased epiphyseal torsion angles compared with healthy volunteers. Values greater than 20° should be considered pathologic. A pathologic retrotorsion of the femoral epiphysis may play a role in developing hip pain related to FAI and premature osteoarthritis.

Alloplastic reconstruction of the extensor mechanism after resection of tibial sarcoma.

Reconstruction of the extensor mechanism is essential for good extremity function after endoprosthetic knee replacement following tumor resection. Only a few biological methods have been able to reliably restore a functional extensor mechanism, but they are often associated with significant complication rates. Reattachment of the patellar tendon to the prosthesis using an alloplastic patellar ligament (Trevira cord) can be an appropriate alternative. In vivo and in vitro studies have already shown that complete fibrous ingrowth in polyethylene chords can be seen after a period of six months. However, until now, no biomechanical study has shown the efficacy of an alloplastic cord and its fixation device in providing sufficient stability and endurance in daily life-activity until newly formed scar tissue can take over this function. In a special test bench developed for this study, different loading regimes were applied to simulate loads during everyday life. Failure loads and failure modes were evaluated. The properties of the cord were compared before and after physiological conditioning. It was shown that rubbing was the mode of failure under dynamic loading. Tensile forces up to 2558 N did not result in material failure. Thus, using an artificial cord together with this fixation device, temporary sufficient stable fixation can be expected.