Various animal models for experimental osteochondral defect healing have been used in orthopaedic research. Two main defect locations were chosen: the patellar groove or the central part of the medial femoral condyles (MFC). To date, it is not clear whether both locations display similar patterns in critical size osteochondral defect healing. We retrospectively analysed both locations in our minipig model hypothesizing that they show similar healing pattern. Thirty-five defects were analysed after three or 12 months. Osteochondral defects were 10 mm deep and 6.3 mm (MFC, n ¼ 19) in diameter or 8 mm and 5.4 mm, respectively (trochlear groove [TG], n ¼ 16). Semi-quantitative histological scoring and histomorphological evaluation were carried out. Both defect locations showed fillings of fibrous and fibrocartilage-like repair tissue. The osseous defect was closed by endochondral bone formation in the MFC. Semi-quantitative scoring did not show differences, whereas qualitative histomorphological analysis more frequently showed cartilaginous repair tissue in MFC defects. There was more frequent subchondral bone cyst formation in MFC location (P ¼ 0.05), TG defects resulted in lower postoperative pain. Both defect localizations are suitable for studies on osteochondral healing. Since regenerating with less hyaline-like repair tissue and less subchondral cyst formation, TG is more favourable for experimental osteochondral defect healing in this model.

Proximal row carpectomy (PRC) is an established procedure in the treatment of advanced radiocarpal arthritis. The aim of this study was to evaluate the individual, functional and radiological results in relation to the initial diagnosis. Seventeen patients (15 men, two women), who had undergone PRC, were evaluated. Their average age at the time of the operation was 48 years (range 21-70 years). The most frequent diagnosis leading to PRC was scaphoid non-union advanced collapse (SNAC), which was observed in nine patients, while in three cases each the condition treated had been scapholunate advanced collapse (SLAC) and perilunate dislocation, and in two cases, Kienboeck's disease. At the time of the follow-up examination (median 65.41 months), a significant improvement in the range of movement was seen. While only four (36%) of the patients with SNAC had radiological signs of arthrosis of the radiocapitate joint, visible radiological involvement was noted in all patients who underwent PRC due to scapholunate dissociation and perilunate dislocation. The results of this study show that PRC is a good way of achieving long-term improvement of the degree of subjective freedom from symptoms and of the functional range of movement. Interruption of ligamentous structures, as in scapholunate dissociation and perilunate dislocation, seems to influence the radiological outcome.

Cartilage wear after hemiarthroplasty remains a problem in orthopedic surgery. The main cause of cartilage wear, apart from incongruency of the joint partners, is generally considered to be the tribology of the material surfaces. This study evaluates in 27 rabbits the degree of cartilage wear of the tibia plateau after hemiarthroplasty with proximal interphalangeal prostheses made of three different materials [cobalt chromium (CoCr), pyrocarbon (PyCa), and ceramic (Cer)]. Three months after hemiarthroplasty, the articulating tibial cartilage was histomorphologically examined and degenerative damage was graded using the modified Mankin score. The mechanical capacity of the cartilage was assessed by stress relaxation testing. The biomechanical properties of the cartilage were significantly superior in the CoCr group as compared with the Cer group (p < 0.03), indicating less damage to the articulating cartilage surface. The Mankin score showed significantly lower values in the CoCr compared with Cer group (p = 0.011), whereas no differences were found between PyCa and CoCr or PyCa and Cer. In contrast to earlier reports, in this hemiarthroplasty model, the CoCr alloy showed less cartilage damage than a ceramic surface. Further, in vivo experiments are necessary to elucidate the controversial issue of the most suitable material for hemiarthroplasty.

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In self-assessment, pain was of higher importance then wrist motion. According to our findings the type of arthrodesis did not influence patient satisfaction. Total wrist arthrodesis should not be excluded categorically as a possible alternative to mediocarpal arthrodesis.

Forearm fractures are very common injuries during growth. In recent years popular sport activities like inline-skating and skateboarding have gained increasing importance as cause of accident. Despite increasing injury rates there are only a few studies describing the correlation between the mechanism of accident and the resulting pattern of injury. The aim of the present study was therefore to analyse the epidemiology and aetiology of forearm fractures in immature patients. Additionally the outcome of treatment was evaluated by clinical parameters.Initially 263 patients could be included in this retrospective cohort study (median: 9.93; range 6-14 years). Beyond classifying patients according to epidemiological and aetiological parameters a clinical and functional follow-up using established scores was performed (DASH score, score by Schmittenbecher et al.). Based on our standard of treatment, stable fractures were treated conservatively, instable fractures surgically. 55 months (range: 12-100) after first attendance 212 patients were followed up personally. With regard to the epidemiology and the aetiology inline-skating was the most common cause of accident (21, 3 %). 82 % did not wear wrist guards while injured. A special pattern of fracture was found only for simple falls, which lead significantly more often to torus buckle and greenstick fractures (p = 0.008). According to the classification described by Schmittenbecher et al., 75 % of the patients were graded as "excellent". There was a significant better outcome for simple fractures compared to complete fractures (p = 0.029).However, the type of treatment (conservative vs. surgical) did not have an influence on the overall result.

In hand surgery multiple different alloarthroplasties are available. However, the clinical outcome of them is largely unknown. Therefore, clinical evaluation of the different alloarthroplasties is essential. To ensure the quality standards that exist in endoprostheses of large joints the initialization of a central alloarthroplasty registry is essential.

Scapholunate dissociation is one of the most common disorders of the wrist. Untreated it might lead to osteoarthrosis (scapholunate advanced collapse, SLAC wrist). Choosing the best surgical treatment option is still challenging, especially in cases of carpal collapse in combination with beginning osteoarthrosis of the radial styloid and the proximal pole of the scaphoid. We report the results of a homogenous group of eight patients with reducible carpal collapse and beginning arthrosis treated by reconstruction of the scapholunate ligament. The operation was performed 66 (range: 20 to 252) months after trauma. The average length of follow-up was two years. Five patients stated general improvement, while three reported a change for the worse. At follow-up, the average total range of motion of the operated wrist was decreased by 16 % compared to the unaffected side. The average grip-strength (measured with a Jamar dynamometer) was 77 % of the uninvolved wrist. The DASH score was 43 +/- 25. In three cases the Martini score showed a good or an excellent result. The average scapholunate angle was 72.3 degrees preoperatively and decreased to 61.0 degrees at follow-up. At follow-up as well as pre- and postoperatively the carpal height ratio showed pathologic mean values. Therefore, reconstruction of the carpal alignment was not achieved in most of the cases. Progression of the osteoarthrosis has to be expected. Reconstruction of the scapholunate ligament for treatment of carpal collapse with beginning osteoarthrosis therefore remains an unsolved problem.