Several controversies exist regarding the surgical difficulties and the results of total knee arthroplasty performed after failed valgus high tibial osteotomy (HTO), and the main subject is the change in patellar height that results as patella baja or infera. The purpose of this retrospective study was to evaluate patellar height after valgus HTO and the measurement methods that were actually used. Eighty-five knees that were subjected to valgus HTO were evaluated both preoperatively and postoperatively according to the Insall-Salvati Index (ISI), Blackburne-Peel Index (BPI), and Caton Index (CI) to assess any alteration of patellar tendon height that was present. All cases underwent closing wedge osteotomy with three staples or plate internal fixation and were allowed early range of motion. Significant decrease in mean patellar height ratios was detected according to all three indexes at 85 months of mean follow-up. The percentages of the decrease were 8.26% in ISI, 9.08% in BPI, and 6.34% in CI. Two knees showed patella infera according to ISI, one according to BPI and three according to CI. There were no significant correlations between the indexes and clinical status of the patients. Elevation of patella relative to the femur in closing wedge valgus HTO procedure due to the shortening of the segment between tibial tuberosity and joint line is normally expected. A significant decrease in patellar height according to ISI suggests that there should be patellar tendon shortening as patellar height cannot be changed. BPI and CI for determining patellar height in valgus HTO do not accurately measure the alteration of patella because they may affect the tibial inclination and antero-posterior translation of the proximal fragment. Another measuring system based on femoral reference points should be proposed to determine the exact change of patellar height in the valgus HTO procedure.
We found a significant VMO weakness, and this method may provide quantitative data that might influence the diagnosis of muscle weakness, in female patients with PFPS.
Extensive calcification of the patellar tendon following ACL reconstruction with central-third bone-patellar tendon-bone autograft is a rarely seen complication. A 45-year-old male patient underwent combined intraarticular reconstruction of ACL with 1/3 central patellar bone-tendon-bone graft and extraarticular reconstruction with modified MacIntosh technique. Two cm of calcification of the patellar tendon was observed incidentally when he underwent a high tibial osteotomy due to medial compartment degeneration, secondary to varus malalignment, 18 months after the ACL surgery. The calcification, being painless, was left untouched during the surgery. At the final examination, 136 months postoperatively, the patient still had no complaint relating to the patellar tendon.
The shortening of the tendon occurs as a result of adherence in the distal part of the tendon. It would appear that it is this shortening that causes the difficulties encountered during arthroplasty surgery of osteotomy patients, and not patella infera.
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