Introduction. Osteochondral defects of the knee may occur following patella dislocation or following direct trauma or twisting injuries to the knee in adolescents. Often a diagnostic and therapeutic challenge, if these lesions are left, posttraumatic osteoarthritis may occur. This retrospective single centre study presents the short-term results following operative fixation of osteochondral fragments of the knee using Omnitech ® screws. Method. All skeletally immature patients presenting with an osteochondral fracture of their femur or patella confirmed on xray and MRI were identified. Arthroscopic evaluation of the osteochondral defect was performed followed by open reduction and internal fixation of the osteochondral fragment using Omnitech ® screws. A standard postoperative rehabilitation protocol was followed. Patients were evaluated at follow-up using a Knee Injury and Osteoarthritis Outcome Score (KOOS). Results. Eight patients were identified. The mean age at time of injury was 15 years (range 14–16) for two girls and 14.4 years (range 13–16) for six boys. The lateral femoral condyle was involved in six cases and patella in two cases. At mean follow up of 14 months (range 1–38) there was no revision for failure and no postoperative complications. The KOOS score (out of 100) at final follow up was subdivided as follows; Pain, 93 (range 81–100), other symptoms, 77 (range 36–100), function in daily living (ADL), 97 (range 84–100), function in sport and recreation, 84 (range 55–100) and knee related quality of life, 79 (range 44–100). Discussion. The short-term results of using Omnitech® screws are promising. Subchondral screw placement with adequate compression of the osteochondral fragment is achievable with Omnitech ® screws. Seven patients are back to their pre-injury sporting activity and one patient is currently undergoing postoperative rehabilitation, one month following surgery

Osteochondral fracture of the femoral head is an uncommon injury with a high potential for a poor functional outcome. Management is often challenging with limited options. We present two cases in which osteochondral fractures of the femoral head were treated with partial resurfacing using the HemiCAP System (Arthrosuface, Franklin MA, USA). Patient 1. A 22-year-old male professional motorbike rider presented with an anterior left hip dislocation that occurred during a race. A CT scan after a closed reduction revealed a large osteochondral impaction fracture/defect that was addressed via partial resurfacing using the HemiCAP System. Patient 2. A 34-year-old male presented with an anterior left hip dislocation after a motor vehicle accident and underwent a closed reduction. CT showed a loose osteochondral fragment, that was fixed back with headless screws, and an adjacent defect was addressed with a HemiCAP implant. Both patients were kept non weight-bearing for two months and had an uneventful recovery. Patient 1 was last reviewed at our institution one month post-operatively with a pain-free hip. His follow-up is being continued interstate and at telephone interview, 18 months after surgery, he had returned to full function and resumed riding on the professional racing circuit. Patient 2, at three-month review, had a pain-free hip with a full range of motion. CT scan showed excellent joint surface congruity at the implant articular surface junction. We report the use of the HemiCAP System as a novel method of treating osteochondral defects, which has never been reported before. There has only been one other reported case of using a HemiCAP in an osteoarthritic femoral head. This is a short follow-up with only two patients treated; however we are encouraged by the results so far, as there are no other satisfactory alternative treatment options

Juvenile Osteochondritis dissecans (JOCD) in humans and subchondral cystic lesions (SCL) in horses (also termed radiolucencies) share similarities: they develop in skeletally immature individuals at the same location in the medial femoral condyle (MFC) and their etiology is only partially understood but trauma is suspected to be involved. JOCD is relatively uncommon in people whereas SCLs arise in 6% of young horses leading to lameness. Ischemic chondronecrosis is speculated to have a role in both osteochondrosis and SCL pathogenesis. We hypothesize that MFC radiolucencies develop very early in life following a focal internal trauma to the osteochondral junction. Our aims were to characterize early MFC radioluciencies in foals from 0 to 2 years old. Distal femurs (n=182) from Thoroughbred horses (n=91, 0–2 years old), presented for post-mortem examination for reasons unrelated to this study, were collected. Radiographs and clinical tomodensitometry were performed to identify lesions defined as a focal delay of ossification. Micro-tomodensitometry (m-CT) and histology was then performed on the MFCs (CT lesions and age-matched subset of controls). Images were constructed in 3D. The thawed condyles, following fixation, were sectioned within the region of interest, determined by CT lesion sites. Hematoxylin eosin phloxin and safran (HEPS) and Martius-Scarlet-Blue (MSB) stains were performed. Histological parameters assessed included presence of chondronecrosis, fibrin, fibroplasia and osteochondral fracture. An additional subset of CT control (lesion-free) MFCs (less 6 months old) were studied to identify early chondronecrosis lesions distant from the osteochondral junction. One MFC in clinical CT triages controls had a small lesion on m-CT and was placed in the lesion group. All m-CT and histologic lesions (n=23) had a focal delay of ossification located in the same site, a weight bearing area on craniomedial condyle. The youngest specimen with lesions was less than 2 months old. On m-CT 3D image analysis, the lesions seemed to progressively move in a craniolateral to caudomedial direction with advancing age and development. Seventy-four percent (n=17/23) of the lesions had bone-cartilage separation (considered to be osteochondral fractures) confirmed by the identification of fibrin/clot on MSB stains, representing an acute focal bleed. Fibroplasia, indicating chronicity, was also identified (74%, n=17/23). In four cases, the chondrocytes in the adjacent cartilage were healthy and no chondronecrosis was identified in any sections in the lesions. Nineteen cases had chondronecrosis and always on the surface adjacent to the bone, at the osteochondral junction. None of the subset of control specimens, less than 6 months old (n=44), had chondronecrosis within the growth cartilage. Early subchondral cystic lesions of the medial femoral condyle may arise secondary to focal internal trauma at the osteochondral junction. The presence of fibrin/clot is compatible with a recent focal bleed in the lesion. Medial femorotibial joint internal forces related to geometry could be the cause of repetitive trauma and lesion progression. In the juvenile horse, and potentially humans, the early diagnosis of MFC lesions and rest during the susceptible period may reduce progression and promote healing by prevention of repetitive trauma, but requires further study