Patellofemoral Instability Surgery

Patellofemoral instability surgery is a specialized knee procedure performed at Moolchand Hospital, one of the best orthopaedic hospitals in Delhi. Patellar instability occurs when the patella (kneecap) repeatedly dislocates laterally or subluxes (partially slips) out of the femoral trochlear groove — the smooth cartilage-lined channel on the front of the femur where the patella normally glides. Each episode of dislocation or subluxation causes pain, swelling, apprehension during activity, osteochondral injuries (cartilage and bone damage), and significant functional limitations.

Understanding the underlying anatomical risk factors is critical for surgical planning. These include increased tibial tubercle-trochlear groove (TT-TG) distance (measuring lateral patellar pull from the quadriceps vector), trochlear dysplasia (an abnormally shallow or flat femoral groove providing inadequate bony constraint), patella alta (high-riding patella), excessive femoral anteversion, and medial patellofemoral ligament (MPFL) insufficiency — the primary static restraint preventing lateral patellar displacement, torn in virtually every acute patellar dislocation.

MPFL reconstruction is the most commonly performed procedure for recurrent patellar dislocation with normal anatomy (TT-TG distance ≤20mm, no significant trochlear dysplasia). A hamstring tendon autograft (gracilis) or synthetic graft is used to reconstruct the MPFL — anchored to the medial femoral condyle and the medial patella — restoring the ligamentous restraint that prevents lateral displacement. MPFL reconstruction alone achieves excellent outcomes in appropriately selected patients with a redislocation rate below 5%.

When TT-TG distance is elevated (greater than 20mm), anteromedialization of the tibial tubercle (Fulkerson osteotomy or Elmslie-Trillat procedure) reduces the lateral pull of the quadriceps on the patella, normalizing alignment. This bony correction is often combined with MPFL reconstruction for comprehensive instability correction.

Trochleoplasty — surgical deepening and reshaping of the shallow or flat trochlear groove — is reserved for severe trochlear dysplasia (Dejour type B, C, D) where a bony bump (supratrochlear spur) causes the patella to ride over it, contributing to instability. This technically demanding procedure provides the bony constraint essential for stability in severe dysplasia.

At Moolchand Hospital in Lajpat Nagar Delhi, our knee specialist orthopaedic surgeons provide comprehensive patellofemoral instability evaluation — including CT measurement of TT-TG distance, MRI assessment of cartilage, and trochlear morphology analysis — before designing a patient-specific surgical plan combining the appropriate procedures for each individual's anatomy.