SLR - December 2011 - Steve Czymbor
Reference: Fansa, A.M., Murawski, C.D., Imhauser, C.W., Nguyen, J.T., Kennedy, & J.G. (2011). Autologous osteochondral transplantation of the talus partially restores contact mechanics of the ankle joint. The American Journal of Sports Medicine, 39, 2457-2469.
Scientific Literature Review
Reviewed by: Steve Czymbor, DPM
Residency Program: Columbia St Mary’s Hospital, Milwaukee, WI
Podiatric Relevance:
The tibiotalar contact area of the ankle joint is unique in that is has significant changes in pressures between the surfaces during an anatomical gait pattern. Small shifts in alignment in the ankle joint have been shown to significantly change overall contact areas of this joint. Osteochondral injuries to this area are common, especially with inversion sprains and ankle fractures. This study is relevant in analyzing the talar contact area after repair of the talus in these injuries.
Methods:
10 fresh frozen cadaveric specimens were used, being prepared in identical fashion. An 8mm centromedial quadrant osteoch ondral defect was made on the talus with harvesting of specimen from the ipsilataral knee, lateral ridge of the lateral femoral condyle. Specimens were loaded in an inverted state with a 300-N compressive force applied. Analysis of pressure on the talar surface after an anterior ankle arthrotomy and sectioning of all anterior tendons and capsule, leaving ankle ligaments intact. Measurements were taken prior to OCD creation, with OCD defect, and post-repair.
Results:
OCD creation decreased medial region force an average of 67%, with implantation of graft restoring forces to 94% of original measurements with changes most noted in the anterior medial region. On average, the anterior portion of the graft only carried 55% of applied force seen from the intact model. Graft height was sunken by a mean measurement of 0.2mm with the lateral portion being the most sunken with an average 0.4 mm, although no significant difference in peak or mean force could be correlated with the varying heights.
Conclusions:
Autologous osteochondral transplantation of the talus is a viable method of repair for talar defects along the centromedial quadrant in relation to force mechanics. When forces are measured for 8 mm defects, it is shown that there is restoration of regional contact mechanics on the medial third of the ankle within 6% even though the graft itself only carries 55% of the original contact model.