Clinical Results of the Multiple Drilling for Osteochondral Lesion of the Medial Talar Dome / 대한정형외과학회잡지

PURPOSE: To evaluate the treatment outcomes of transmalleolar multiple drilling with a K-wire for an osteochondral lesion of the medial talar dome after an mean follow-up period of 77 months. MATERIALS AND METHODS: Among patients treated surgically for a symptomatic osteochondral lesion of the talus between March 1997 and December 2002, sixteen ankles (fifteen patients) with a medial talar dome lesion were treated by transmalleolar multiple drilling and followed-up for at least 3 years. The average age at the time of surgery was 34.4 years (range, 19-58 years). The mean follow-up period was 77 months (range, 41-107 months). RESULTS: At the latest follow-up, the average VAS at motion decreased from 6.8 to 2.1 (p=0.004). The AOFAS score improved from 64 points to 86.2 points (p=0.001). The 8 ankles in those less than thirty years of age at that time of surgery showed a VAS at motion of 1.8 and an AOFAS score of 91.1 points. In contrast, 8 ankles in those who older than thirty one years of age had a VAS at motion of 2.4 and an AOFAS score of 81.2 points. The younger group showed a significantly better AOFAS score than the older group (p=0.001). However, there was no significant difference in the VAS score (p=0.22). CONCLUSION: Multiple drilling has a good effect in pain control and ankle function for patients with an osteochondral lesion of the medial talar dome 10 mm. The procedure is particularly effective and useful in younger patients.

Local compressive strength of the superolateral and sueromedial aspects of the anterior half of the talar dome: A biomechanical and histological study.

One cause of osteochondritis dissecans of the talar dome is related to trauma. The lesion occurs at the anterior half of the talar dome. The lateral osteochondritis dissecans is located at the superolateral aspect, while the medial lesion is located at the superomedial aspect. The lateral lesion is more common and its crater is shallower than that of the medial lesion. This study was therefore carried out to determine the local compressive strength of the superolateral and superomedial aspects of the anterior half of the talar dome. Ten pairs of fresh normal cadaveric tali were obtained. Using a universal testing machine, a compressive load was applied through a metal indenter at the superolateral and superomedial aspects of the talar dome until the maximal load was obtained. The maximal load and depth of depression were recorded. Histological studies of the compressive lesion was done using decalcified hematoxylin eosin stain. The results of the study showed that the superolateral aspect of the talar dome could withstand 1.27 times less compression load than could the superomedial aspect without a significant difference in stiffnesses. Moreover, the depth of depression of the superolateral compressive lesion was shallower than that of superomedial. Histological studies showed that the compressive lesion was a depression fracture. The depression fracture was a free osteochondral fragment surrounded by normal osteochondral tissue. The free fragment included articular cartilage, subchondral plate, and subchondral cancellous bone. The result of this study may explain why the prevalence of the lateral traumatic osteochondritis dissecans is higher, and its lesion crater shallower, than that of the medial aspect of the talar dome.

Local compressive strength at the middle of the weight-bearing surface of the femoral head and talar dome: A biomechanical study.

Objective: To compare the local compressive strength at the middle of the weight bearing surface of the femoral head and talar dome. Design: Cadaveric and comparative experimental study. The compressive strength of the talar dome and the femoral head were measured and compared. Background: The prevalence of late collapse of femoral head from avascular osteonecrosis is higher than that of the talar dome. The femoral head and acetabulum form a hip joint with monoarticulation whereas the talus itself has several articulations with several bones, so the talar dome distributes load more effectively from it the surroundings than does the femoral head. Compressive strength of the weight bearing surface of the femoral head and talar dome, however, may play a role in late collapse. Methods: Ten fresh cadaveric normal adult femoral heads and tali were obtained. A compressive load was applied through an indenter at the middle of the superior quadrant of the femoral head and talar dome by using a universal testing machine until a maximum load was obtained. The maximum load and depth of depression at maximum load were recorded. Results: The middle of the weight bearing surface of the femoral head could withstand an average maximum pressure of 30.42 MPa. Its stillness was 929.04 N/mm and its depth of depression was 1.11 mm. The corresponding figures for the talar dome were 49.64 Mpa, 1631.65 N/mm, and 0.96 mm respectively. Conclusion : This study showed that local compressive strength at the middle of the weight bearing surface of the talar dome was 1.63 times greater than that of the femoral head. Relevance : This finding may explain the higher prevalence of late collapsing avascular necrosis of the femoral head than that of the talar dome.