Mapping subchondral bone density of selected donor and recipient sites for autologous osteochondral transplantation in the canine stifle joint using computed tomographic osteoabsorptiometry.

Objective: To characterize donor and recipient sites for autologous osteochondral transplantation (AOT) in the canine stifle joint with respect to maximal subchondral bone density (mSBD).

Study Design: Descriptive laboratory study.

Sample Population: Femora (n=15) of dogs (>20 kg).

Methods: mSBD at selected donor sites within and outside the femoropatellar joint and at potential recipient sites for both femoral condyles was assessed using nonvolumetric computed tomographic osteoabsorptiometry and normalized to values obtained at the central weight-bearing aspect of the lateral femoral condyle.

Results: Only transplants harvested at the axial aspects of the lateral and medial trochlear ridge had a normalized mSBD comparable with the lateral and medial femoral condyle. Grafts from outside the femoropatellar joint, at the most proximal aspect of the medial femoral condyle and at the most distal aspect of the trochlea (the notch area) had mSBD values 13.8-24.4% less than at the femoral condyles.

Conclusions: Choosing between donor sites within or outside the femoropatellar joint may significantly affect subchondral bone quality of harvested transplants.

Clinical Relevance: Donor sites abaxial to the femoropatellar joint and at the most proximal aspect of the medial femoral condyle may provide transplants of suboptimal bone morphology, challenging their use as primary donor sites for AOT in dogs. However, this statement is based on nonvolumetric assessment of bone density, necessitating verification using volumetric density analysis to finally infer the biomechanical value of different grafts.