Patella infera or patellar tendon adherence after high tibial osteotomy

Alterations in patellar height after high tibial osteotomy are found in many instances. Fibrosis of the tendon is implicated as the cause of the mechanism of patella lowering. This study aimed to determine the relationship between the position of the patella and the histopathological findings at the patellar tendon after high tibial osteotomy.

Nineteen knees in seventeen patients who were consecutively hospitalised for implant extraction are studied. All of the patients had previously undergone closing wedge osteotomy by the same surgeon at the same department. The median follow-up time is 15 months (range: 11-35). Five patients who all underwent high tibial osteotomy at the same time are also included in the study as a control group for histopathological evaluation. All of the patients are evaluated radiologically, patellar tendon biopsies are taken during the operation, and histopathological analyses are performed.

The shortening of the patellar tendon is statistically significant (P < 0.05). The severity of the vascularisation, inflammation, and fibrotic change observed at the distal part of the tendon is evident. However, there is no statistically significant correlation between these findings and the degree of shortening.

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.