Examination for tibiofemoral abnormality, patellofemoral malalignment indicated for patients with untreated hip dislocation and knee pain

Aksahin E. Knee Surg Sports Traumatol Arthrosc. 2011. doi: 10.1007/s00167-011-1807-3.

Patients with knee pain and untreated bilateral or unilateral developmental hip dislocation should be analyzed for both tibiofemoral abnormalities and patellofemoral malalignment, researchers from Turkey concluded.

The researchers examined 14 patients with bilateral developmental hip dislocation and 25 patients with unilateral hip dislocation. The mean age in the unilateral hip dislocation group was 33.3 years, in the bilateral dislocation group was 36.2 years and in the control group was 31.5 years. Controls consisted of CT results of 24 asymptomatic adult knees.

The researchers analyzed the patellofemoral parameters of the unilateral and bilateral developmental hip dislocation groups and the control group, according to the abstract, as well as the effect of femoral anteversion, limb length discrepancy, severity of dislocation, and the mechanical axis deviation on those parameters.

In the unilateral group, they found the patella was more lateral at initial flexion degrees, but was more medial at 30° flexion and 60° flexion relative to the control group. Patellar tilt angles for the involved extremity at 15°. Thirty degrees and 90° flexion were significantly greater in the control group “corresponding to medial patellar tilt,” according to the abstract. In the bilateral hip dislocation group, “the course of the patella during tracking in terms of patellar shift was similar to that of the unilateral patients,” the authors wrote.