Role of computed tomography in diagnosis and clarifying the classification of patello-femoral malalignment

The role of the conventiomal axial radiographs of the patellofemoral joint in assessing patients suffering from peripatellar pain is limited. Therefore Computed Tomography [CT] was used to evaluate 40 patients with persistent patello-femoral pain, and ten asymptomatic volunteers as a control group. Mid patellar transaxial cuts were taken for all of them at 0, 15, 30 and 45 dgress of knee flexion. The congruence angle, the patellar tilt angle and the femoral trochlear angle were obtained from each image. According to the values of these three angles, patients were classified using Merchant's classification of patello-femoral malalignment into: Type I malalignment [patellar subluxation only - 12 cases]. Type II malalignment [patellar subluxation and tilt - 10 cases]. Type III malalignment [patellar tilt only - 13 cases]. The CT has a significant advantage in diagnosing and identifying the different patterns of patello-femoral malalignment particularly when surgical realignment is planned

Patellar non resurfacing during total knee arthroplasty

There has been no universal agreement so far regarding the necessity of patellar resurfacing in total knee arthroplasty. As resurfacing has been reported to be associated with high incidence of complications, we undertook a prospective study to evaluate the functional outcome of twenty one patients [22 kness=22cases] who had no patellar resurfacing during knee replacement. The underlying diagnosis was osteoarthritis in twenty cases and rheumatoid arthritis in two cases. The average age was 65 years [range 54 - 75 years], there were six males and fifteen females [one was bilateral], the average period of follow up was 28 months [range 6 months - 36 months], patients were classified into three groups according to the grade of the patellar cartilage detected intraoperatively. Preoperative and final assessment were done according to the Hospital for special surgery [HSS] knee scoring system and the patellar scoring system. Excellent and good results were obtained in nineteen cases [86.4%]. The mean HSS score improved from 43.4 preoperatively to 80.9 postoperatively and the mean patellar score improved from 12.6 preoperatively to 24.6 postoperatively. When we compared the final results in the three groups of patients we found that the grade of the patellar cartilage have played an important role in the final outcome. Results in patients with grade II patellar cartilage were better than grade III and both were much more superior to patients with grade IV. We concluded that patellar resurfacing should not be a routine step in knee replacement particularly in presence of satisfactory patellar articular cartilage