[Surgical treatment of secondary patella baja following total knee arthroplasty]

Improvement of knee joint function through proximalisation of the patella, increase in range of motion (ROM) and reduction of anterior knee pain.

Secondary patella baja following implantation of total knee arthroplasty with shortening of the patellar tendon or scarring of periarticular soft tissues (e.g. Hoffa's fat pad). Particularly in cases of functional impairment of the extensor mechanism and failure of conservative measures.

Infection (preoperative joint aspiration recommended), lack of compliance, inability to undergo postoperative rehabilitation, and pseudo-patella baja due to joint line proximalisation.

Release/arthrolysis: release of infrapatellar, anterolateral and femoral adhesions; tendon lengthening using Z‑plasty, if necessary. Tuberosity osteotomy: oblique osteotomy of the tibial tuberosity with distal shift of the fragment and screw fixation.

Early functional physical therapy and continuous passive motion device for the knee. Full weight-bearing possible immediately after surgery. After tuberosity osteotomy, partial weight-bearing (approximately 15 kg for 6 weeks) with gradual increase in weight-bearing after radiological consolidation.

The literature on isolated release is limited, with isolated case reports showing functional improvements. For tuberosity osteotomy, there are case series reporting improvements in clinical scores (e.g. Kujala, Knee Society Score) and patella height indices. Nevertheless, postoperative limitations remain possible.