Purpose: Joint distraction has been used to treat osteoarthritis and was found to delay the need for arthrodesis or joint replacement. However, there has been little basic research on articulated joint distraction for the repair of osteochondral defects. We investigated the effects of joint distraction with motion after drilling on a fresh osteochondral defect in the weight bearing area of the rabbit knee joint. Methods: A full thickness osteochondral defect was created in the weight bearing area of both medial femoral condyles of an adult Japanese white rabbit. After drilling of the defect, the experimental knee joint was distracted for 1.5 mm using a pair of external fixators to decrease compression force. The contralateral knee joint was used as a control with no apparatus. Gross findings and histological evaluation were assessed to study morphology of the repaired cartilage. Results: A partial repair with cartilage‐like tissue was observed in the joints of the experimental group at 4 weeks. While cartilagelike tissue stained with Safranin O was found in the experimental group at 8 and 12 weeks, destructive changes were observed in the control joints. Morphological changes were evaluated using the histological grading scale [Wakitani S, Goto T, Pineda SJ, et al. Mesenchymal cell‐based repair of large, full‐thickness defect of articular cartilage. J Bone Joint Surg Am 1994;76(4):579–92]. There was no significant difference between experimental and control groups at 4 weeks (mean 11.2 and 13.8 points, respectively). However, the mean scores of the experimental groups at 8 and 12 weeks (mean 6.8 and 7.5, respectively) were significantly better than those of the control groups at the same time points (mean 14 points each). Between the experimental groups, the scores at 8 and 12 weeks were both significantly better than those at 4 weeks. Conclusion: A combination of subchondral drilling, joint motion and distraction by an articulated external fixator promoted repair of a fresh osteochondral defect in the weight bearing area. Although distraction for 4 weeks was not a long enough period to repair the defect, distraction for 8 and 12 weeks resulted in a good outcome. © 2005 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.

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Osteochondral flap fracture in a child is rare. A 7 year-old boy with an osteochondral flap fracture is reported. Intraoperatively, the osteochondral fragment in the olecranon fossa was connected to a part of the medial collateral ligament. The authors suppose that this type of fracture occur not only as a result of a shearing force of the trochlea but also by a traction force through the medial collateral ligament when a complete tear of the medial collateral ligament was avoided for any reason. Furthermore, the immaturity of bone of the child may result in avulsion fracture, not in injury of the distal part of the ligament. Osteosynthesis with poly-L-lactic acid pins was useful to reacquire good elbow function.

We report a case of an anterior interosseous nerve palsy after closed reduction and percutaneous pinning of open fractures of the radius and ulna in an adult. Operative findings showed that the anterior interosseous nerve was trapped between the distal and proximal part of the fractured radius. Treatment by neurorrhaphy gave a satisfactory result.