Histological evaluation of calcaneal tuberosity cartilage--A proposed donor site for osteochondral autologous transplant for talar dome osteochondral lesions.

BACKGROUND: Osteochondral Autologous Transplant (OATs) as a treatment option for Osteochondral lesions (OCLs) of the talar dome frequently uses the distal femur as the donor site which is associated with donor site morbidity in up to 50%. Some studies have described the presence of hyaline cartilage in the posterior superior calcaneal tuberosity. The aim of this study was to evaluate the posterior superior calcaneal tuberosity to determine if it can be a suitable donor site for OATs of the talus METHODS: In this cadaveric study, we histologically evaluated 12 osteochondral plugs taken from the posterior superior calcaneal tuberosity and compared them to 12 osteochondral plugs taken from the talar dome. RESULTS: In the talar dome group, all samples had evidence of hyaline cartilage with varying degrees of GAG staining. The average hyaline cartilage thickness in the samples was 1.33 mm. There was no evidence of fibrocartilage, fibrous tissue or fatty tissue in this group. In contrast, the Calcaneal tuberosity samples had no evidence of hyaline cartilage. Fibrocartilage was noted in 3 samples only. CONCLUSIONS: We believe that the structural differences between the talus and calcanium grafts render the posterior superior clancaneal tuberosity an unsuitable donor site for OATs in the treatment of OCL of the talus.

Bilateral atraumatic tibial tubercle avulsion fractures: case report and review of the literature.

An avulsion fracture of the tibial tubercle is an uncommon injury, comprising less than 1% of all physeal injuries. The occurrence of such injuries bilaterally is even rarer. We report a case of bilateral atraumatic tibial tubercle avulsion fractures and its presentation, mechanism of injury, surgical management, post-operative rehabilitation and implications for clinical practice. A 17-year-old healthy male presented to the emergency department with severe pain on the anterior aspect of both knees and was unable to walk, having been brought in by ambulance after hearing a crack whilst jogging. On examination, there was significant swelling of both knees which were held in extension. On both sides there was a prominent deformity on the region of the tibial tubercle with a palpable gap, although no open skin wound. He was unable to actively move either knee joint. No neurovascular deficit was present. Plain radiographs revealed bilateral tibial tubercle avulsion fractures. Gentle manipulation was performed in the emergency department to the fragments in order to remove the tension from the skin. The fragments were reduced and fixed surgically with 4mm cannulated screws in an anterior to posterior direction. Both limbs were placed in temporary casts in 20 degrees of flexion. Postoperatively, the patient was kept non-weight bearing for four weeks then placed into a range of motion brace and movement commenced. Full weight bearing was permitted at the one month stage and he was advised to avoid any sporting activity until the 8 week stage and contact sports until the 10 week stage. Full movement of both joints was regained and the patient returned to full sporting activity in the absence of symptoms. This case emphasises the need for a high degree of vigilance when faced with such a presentation and a low threshold for further investigation and surgical intervention.