OBJECTIVE The aim of this study was to analyze the setting for dislocations and redislocations after primary and revision total hip arthroplasty (THA), identify risk factors and optimize treatment. METHODS This study included 56 patients with a dislocated hip following THA (n=5,205) between 1984 and 2005 and a matched control group (n=55). Hospital charts and radiographs of all patients in both groups were analyzed. Thirty-one patients in the study group were followed both clinically and radiologically. RESULTS The dislocation rate after primary THA was 1.1% (56/5,205) and the redislocation rate after a first occurrence was as high as 39%. There was a positive correlation between the time intervals from the surgery to first dislocation and from the first dislocation to second dislocation (r=0.4). Most of the primary dislocations occurred within a short period of time after surgery, thus favoring consecutive dislocations. Female gender, as well as revision arthroplasty, was associated with a higher incidence of dislocations. No relation was found between the orientation of the acetabular cup and dislocation. CONCLUSION To prevent redislocations after the first occurrence, we suggest thorough evaluation of possible technical faults which should be addressed surgically. Considering the high redislocation rate, we also advocate a stringent conservative treatment regime especially after the first THA dislocation.

Background: Chopart's joint is fundamental to foot function. Until today, intra-articular force and peak pressure has not been investigated under dynamic conditions.Methods: The study used a cadaver model to measure intra-articular force and peak pressure with electronic sensors. Force was applied to extrinsic tendons via cables attached to computer-regulated hydraulic cylinders. A ground reaction force of 350 N was simulated in a tilting angle- and force-controlled translation stage.Results: We observed a characteristic rising curve with a peak during push-off for intra-articular force and peak pressure. The increase of intra-articular force at the talonavicular and calcaneocuboid joint from a low level at heel-on varies up to a maximum of 174 N/149 N and a peak pressure of 3877 kPa/3396 kPa, respectively, at push-off. We observed highest loading at the dorsal aspect of the talonavicular joint and the plantar aspect of calcaneocuboid joint.Conclusion: The highest loading on Chopart's joint is attained during push-off. We observe higher force and peak pressure on the medial column of the foot compared to the lateral column. The higher load of the dorsal aspect of talonavicular joint and plantar aspect of calcaneocuboid joint confirms the theory of a previous described locking mechanism for forceful push-off. (c) 2007 Elsevier B.V. All rights reserved.

References 1. Dominici M, Le Blanc K, Mueller I, Slaper-Cortenbach I, Marini F, Kraus D, Deans R, Keating A, Prockop Dj, Horwitz E: Minimal criteria for defining multipotent mesenchymal stromal cells. The ISCT position statement. Cytotherapy 2006, 8:315-7. 2. Bruder SP, Kurth AA, Shea M, et al.: Bone regeneration by implantation of purified, culture-expanded human mesenchymal stem cells. J Orthop Res 1998, 16:155-162. from 15th Paediatric Rheumatology European Society (PreS) Congress London, UK. 14–17 September 2008

Osteonecrosis is a frequent complication after treatment for childhood leukemia and other steroid-based therapies. The success rate of core decompression surgery is limited. Therefore, we evaluated relevant biological characteristics of human multipotent mesenchymal stromal cells (MSCs) in vitro. MSCs cultured under low-oxygen tensions showed decreased proliferation and differentiation into bone. However, these MSCs secreted significant amounts of vascular endothelial-derived factor in the presence of interferon-γ. These in vitro results with potential effects on neovascularization and bone regeneration as well as findings in animal models prompted us to treat five patients with steroid-induced osteonecrosis of the femur by core decompression surgery and instillation of expanded autologous MSCs. Within 3 weeks of culture, sufficient numbers of MSCs were generated using animal protein-free culture conditions. No chromosomal aberrations were detected by matrix-based comparative genomic hybridization. Application of MSCs during core decompression was feasible and safe. Median follow-up is 16 months and the patients in this pilot study reported clinical improvement. Formation of mineralized bone in the osteonecrotic cavity was proven by computed tomography. Taken together, MSCs display biological properties that may add to the efficiency of surgical treatment in osteonecrosis and should be evaluated in larger patient cohorts.

Mesenchymal stromal cells are multipotent cells capable of tissue repair and immune modulation. They are primarily found in bone marrow, but are also present in other tissues of mesenchymal origin, such as fatty tissue, muscle, tendons, etc. MSC can easily be obtained by bone marrow aspiration, showing a rapid expansion in vitro. New protocols enable cell culture without the use of animal-derived sera and artificial growth factors. Avascular necroses of the bone may have different causes. AVN in autoimmune and hematological diseases show a strong association with corticosteroid treatment, which is often unavoidable in severe cases. Until recently, core decompression of the affected osseous area was the standard approach. Because of their differentiation properties, easy accessibility and proliferative capacity, autologous MSCs could potentially complement AVN treatment by adding fresh "osteogenic cells" to the healing process.

Background Talonavicular arthrodesis is a differential indication for triple arthrodesis. Differences regarding intraarticular pressure loads on the adjacent joints have not been investigated to date, but they are of clinical relevance when considering long-term joint degeneration. Methods We used a dynamic foot model to measure intraarticular peak pressures with electronic sensors in 8 anatomical specimens in different areas of the ankle joint and in the naviculocuneiform joint. Force was applied to extrinsic tendons via cables attached to computer- regulated hydraulic cylinders. A ground reaction force was simulated in a tilting angle- and force-controlled translation stage. Results We measured significantly higher peak pressures in the ankle joint after triple arthrodesis (5.7 Mpa) than after talonavicular arthrodesis (5.2 Mpa), with differences especially in the anterior section (5.2 Mpa as compared to 4.6 Mpa). Centrally, the peak pressure was similar, at 4.6 MPa and 4.5 Mpa, respectively. In the posterior area, the peak pressure after triple arthrodesis was lower (4.1 MPa as opposed to 4.4 Mpa). After triple arthrodeses, we measured higher values laterally/medially in the ankle joint (5.5 MPa/4.6 Mpa) than after talonavicular arthrodesis (5.1 MPa/4.4 Mpa). In the naviculocuneiform joint, we again saw higher peak pressures after triple arthrodesis than after talonavicular arthrodesis. Interpretation Our findings from this cadaver study indicate a lower and more evenly distributed peak pressure load in the ankle joint after talonavicular arthrodesis than after triple arthrodesis; thus, mechanically, a selective arthrodesis appears to be more favorable. In contrast, triple arthrodesis leads to an increase in peak pressure in the ankle joint, which may in turn lead to joint degeneration.

A total of 118 feet with Hallux valgus and Hallux rigidus treated by the Keller-Brandes method were re-examined clinically and radiologically after 9.1 years (range: 1.7-24.3). Correction of the Hallux valgus angle was obtained from an average of 40 degrees to 23 degrees in the Hallux valgus group. Improvement in the postoperative range of motion was observed when the aftertreatment consisted of Kirschner-wire distraction instead of an axial Kirschner-wire transfixation. The patients who underwent Keller-Brandes surgery for Hallux valgus had less pain when the aftertreatment was carried out using an axial Kirschner wire, while those operated on for Hallux rigidus had less pain when the aftertreatment consisted of distraction. The percentage of satisfied or very satisfied patients with the cosmetic results of the Keller-Brandes arthroplasty was more than 66.7%. Patients with Hallux valgus and postoperative aftertreatment with Kirschner wire transfixation were the most satisfied patients, while patients with Hallux rigidus were very satisfied with the postoperative distraction. Our good results are comparable to those in other studies and confirm the success of the Keller-Brandes resection arthroplasty in Hallux valgus with osteoarthritis of the first metatarsophalangeal joint in older patients whose demand for movement is less, and in Hallux rigidus in less active older patients.

Major transfusion-free orthopaedic surgery can be performed successfully. This requires advanced planning, good routines and close collaborative team efforts. Since most blood saving techniques reduce blood usage by just 1-2 units, a series of integrated preoperative, intraoperative and postoperative blood saving approaches is required. These include preoperative autologous donation, erythropoietic support, acute normovolemic hemodilution, intraoperative autotransfusion, individualized assessment of anemia tolerance, meticulous surgical techniques and the use of pharmacologic agents for limiting blood loss. For various reasons, we do not recommend the transfusion of wound drainage. This article describes the various methods for bloodless medical care.

The Adaptiva custom-made stem is a hip stem anchored by fit and fill press-fit into the proximal femur and manufacture is based on computed tomography (CT) scanning. Its concept was developed for primary and revision hip arthroplasty in younger patients in our clinic. We present the advantages and the disadvantages of the system. After 66 months 98.9% of the patients are satisfied with the surgical outcome; 86% attained very good and 9% good results according to the Merle d'Aubigné score. Despite good clinical results and a high satisfaction rate, we stopped using this stem because we do not see any advantages in comparison with standard implants and feel that the price for a custom-made stem for primary hip arthroplasty is too high.

Background: In this retrospective study, both the patients' and surgeons' satisfaction with resection of the first through fifth metatarsal heads for long-standing rheumatoid forefoot deformity was evaluated. Methods: Thirty-four patients (56 feet) had first through fifth metatarsal head resection. After a mean time of 5.3 years, 39 feet (69.6%) (26 patients) were examined clinically and radiographically. Results: The complication rate was 14% (8 of 56). There were four superficial and four deep wound infections. Plantar pressure pain under the resected metatarsal heads occurred in six feet. Most patients rated their cosmetic and functional results as good. Eighteen percent of patients (6 of 34) were satisfied and 78% (26 of 34) were satisfied with reservations. Thirty-three percent of patients (11 of 34) were pain free and 53% (18 of 34) had mild pain. The surgeons assessment of the patients' anatomical correction (cosmesis) was good in 90% (50 of 56) and poor in 10% (6 of 56). Conclusions: Our results, which are comparable to those of other studies, confirm the success of metatarsal head resection for the treatment of inflammatory forefoot destruction in rheumatoid arthritis to correct deformity, reduce pain, improve ambulation, and offer the patient a greater variety of shoewear.

AIM:The object of this study was to develop a new method to predict the location of the centre of rotation of the hip joint reasonably accurately. METHOD:We collected the coordinates of palpable bony landmarks in 50 patients, 25 males and 25 females, using CT scans to predict the physiological location of the centre of the hip joint centre. RESULTS:The centre of the hip was located, on average, at 12% (+/- 2.9) of the inter-ASIS (anterior superior iliac spine) distance medial, 33% (+/- 3.9) distal and 19% (+/- 2.7) posterior to the anterior superior iliac spine (ASIS). CONCLUSION:Knowledge of the physiological centre of rotation of the hip may be useful in navigation of the cup in total hip arthroplasty.

Pigmented villonodular synovitis (PVNS) is a rare, strongly proliferative disease of the lining of the joint, synovial bursa and tendon (synovial) sheath. If left untreated, it leads to severe destruction of the joint resulting in an early need for endoprosthetic replacement. The clinical signs are unspecific. Using the diagnostic gold standard MRI, the complete extent of PVNS can usually be determined non-invasively. Once histological confirmation has been obtained, radical tumor resection, synovectomy, possibly curettage, and postoperative irradiation must be applied.

Aim: The object of this study was to develop a new method to predict the location of the centre of rotation of the hip joint reasonably accurately. Method: We collected the coordinates of palpable bony landmarks in 50 patients, 25 males and 25 females, using CT scans to predict the physiological location of the centre of the hip joint centre. Results: The centre of the hip was located, on average, at 12% (+/- 2.9) of the inter-ASIS (anterior superior iliac spine) distance medial, 33% (+/- 3.9) distal and 19% (+/- 2.7) posterior to the anterior superior iliac spine (ASIS). Conclusion: Knowledge of the physiological centre of rotation of the hip may be useful in navigation of the cup in total hip arthroplasty.

AIM:Are autologous blood transfusions sufficient or do we need the transfusion of unwashed or washed wound drainage blood in total hip arthroplasty?METHOD:253 patients undergoing total hip arthroplasty were retrospectively randomized to autologous blood transfusion or transfusion of unwashed wound drainage. We compared the haemoglobin and haematocrit levels as well as the rate of complications.RESULTS:Postoperative blood salvage and reinfusion after total hip joint arthroplasty didn't show any advantages. In 10 % we saw complications after transfusion of unwashed wound drainage.CONCLUSION:We do not recommend the transfusion of wound drainage.

Studienziel: Methode: Ergebnisse: Schlussfolgerung: Aim: Method: Results: Conclusion:

Studienziel: Die Angabe der Pfanneninklination und -anteversion zur Charakterisierung der Pfannenorientierung ist zum einen eine Frage der Definition und zum anderen eine Frage der Patientenlagerung. Die Bestimmung von Pfanneninklination und -anteversion nach Sven-Johannsson und Visser werden per 3D-Berechnungen simuliert und der Einfluss der Beckenkippung in Relation zur Frontalebene quantifiziert und veranschaulicht. Methode: Mittels 3D-Berechnungen werden Röntgenprojektionsbilder an idealisierten Hüftpfannen simuliert und Anteversion und Inklination mit Hilfe des Normalenvektors der Pfannenebene in Abhängigkeit der Beckenkippung berechnet. Ergebnisse: Die Hauptachse des projizierten Pfannenrandes kann ebenso zur Bestimmung der Pfannenorientierung herangezogen werden, wie der Normalenvektor der Pfannenebene. Eine Beckenkippung von 10 Grad verursacht bei konventionellen Auswertetechniken Fehlmessungen in der Anteversion von ca. 8 Grad. Schlussfolgerungen: Zur korrekten Bestimmung der Pfannenorientierung muss die Beckenkippung in Relation zur Frontalebene mit berücksichtigt werden.

Aim: The indication of acetabular inclination and anteversion not only depends on definition but also on a correctly aligned patient. Determination of anteversion and inclination according to Sven-Johannsson and Visser were simulated with 3D calculations. The influence of pelvic tilt in relation to the frontal plane was evaluated and visualized. Method: With 3D calculations of planar X-ray photographs for artificial hip cups the normal vector of the acetabular cup was used to calculate anteversion and inclination. Results: The main axis of the projected acetabular rim is equally suited to determine the cup orientation as the normal vector of the cup plane. Pelvic tilt of about 10 degrees causes measuring errors of about 8 degrees when measured with conventionally used techniques. Conclusion: For the correct determination of cup orientation pelvic tilt in relation to the frontal plane has to be accounted for.

Background Modern navigation techniques allow precise positioning of the acetabular cup relative to the anterior pelvic plane. Variations in pelvic tilt will affect the resulting spatial orientation of the cup.Methods We measured pelvic tilt in 30 volunteers with an inclinometer combined with an ultrasonographic position measurement system. A mathematical algorithm was developed to calculate the resulting cup position measured on standard radiographs, depending on pelvic tilt.Results Average pelvic tilt at rest was −4° in the lying position and −8° in the standing position, and ranged from −27° to +3°. Pelvic reclination of 1° will lead to functional anteversion of the cup of approximately 0.7°.Interpretation Pelvic tilt makes navigation systems referring to the anterior plane inaccurate.