Medial Knee Approach: An Anatomical Study of Minimally Invasive Plate Osteosynthesis in Medial Femoral Condylar Fracture.

OBJECTIVES

To determine the location of distal medial neurovascular structures, identifying a medial "safe zone" for minimally invasive plate osteosynthesis to treat displaced femoral condylar fractures.

METHODS

Eleven uninjured lower-half torsos were dissected on the bilateral medial lower thigh. A longitudinal incision was made at the midsagittal plane of the medial thigh starting 1 cm proximal to the knee joint and extending to the proximal one-third of the femur. Superficial and deep neurovascular structures were dissected. Distances to the medial vastus and adductor compartment were measured.

RESULTS

Mean distances were 160 ± 31.4 mm from the adductor tubercle to Hunter canal; 94 ± 18.3 mm from adductor tubercle to adductor hiatus; 31.8 ± 9.21 mm from Hunter canal to the femoral shaft; and 31.7 ± 7.78 mm from adductor hiatus to femoral shaft. All specimens had a descending genicular artery (DGA) with a mean distance to the adductor tubercle of 98.4 ± 16.0 mm. The muscular branch of the DGA crossed the femoral shaft at approximately 50 mm from the adductor tubercle; the osteoarticular branch ran along the adductor magnus tendon. The nerve to the vastus medialis was at the posterior border of the vastus medialis, entering at a mean 143 ± 63.0 mm from the adductor tubercle.

CONCLUSIONS

Minor neurovascular branches of the DGA may be vulnerable during medial femoral condyle plating. Careful blunt dissection, proper instrumentation, and plate length within 160 mm allow distal medial femur fixation without additional proximal dissection.