# Total knee arthroplasty for knee osteoarthritis associated with abnormal patellar tendon deformity: a case report

## TL;DR

This case report describes a rare knee condition where abnormal patellar tendon attachment led to successful treatment with total knee arthroplasty.

## Contribution

The paper presents a novel case of valgus knee deformity with patellar tendon infiltration into tibial bone marrow.

## Key findings

- The patellar tendon infiltrated the tibial bone marrow instead of attaching to the tibial tubercle.
- Total knee arthroplasty successfully treated the condition with good clinical outcomes over 3 years.
- Preoperative imaging with MRI or CT is recommended for abnormal tibial tubercle defects.

## Abstract

There have been no earlier reports of knee osteoarthritis with valgus knee deformity in which the patellar tendon infiltrates the tibial bone marrow instead of attaching to the tibial tubercle. This case report describes a total knee arthroplasty (TKA) performed for the treatment of a primary knee osteoarthritis resulting from a valgus knee joint position attributed to an abnormality of the patellar ligament attachment. During a TKA, the tendon tissue in the tibial medullary canal interfered with the reamer used to prepare for the stem extensions needed to improve the fixation of the component on the tibia, which had a cortical defect. The arthroplasty succeeded, and good clinical results have been maintained over the 3 years since the surgery. Surgeons should consider careful preoperative examinations by magnetic resonance imaging or CT when an abnormal bone defect is observed at the tibial tubercle on plain X-ray images.