29 year old woman who is a daily wage worker presented to the outpatient department (OPD) with right anterior knee pain since 4 months. She felt a popping sensation in her right knee after slipping from the foot board of a bus while running to catch it 4 months ago. After this episode, she had severe pain and was unable to move her knee. She was then taken to a quack, after a local manipulation and massaging by him she was relieved of acute symptoms but had persistent knee swelling and mild knee pain. Patient returned to her daily activities the next day with minimal knee pain and difficulty in knee movements. She had similar episodes frequently (around 8) episodes since then, particularly during stair climbing, squatting and while boarding or trying to get down a running bus. The patient was evaluated in the OPD, she had severe anterior knee pain, tenderness over medial patellofemoral joint, a positive apprehension test, no hyperlaxity. Her Q-angle was 18°. Radiographs showed lateral patellar tilt, bony fragment in the medial patellofemoral joint, lateral patellar subluxation, Insall-Salvatti Index-0.91, sulcus angle 133°. Magnetic resonance imaging (MRI) showed effusion of knee joint with tear in the MPFL at the patellar attachment, osteochondral defect in the lateral patellar facet and an osteochondral fragment in the medial patellofemoral joint. Of note, she had no other knee surgeries performed to the same knee. An arthroscopy showed chondromalacia of patella, patellofemoral joint maltracking and an osteochondral fracture of lateral facet of patella [].\nThe patient was treated definitively with MPFL reconstruction by the technique described by us. Her pain resolved in 3 weeks, she returned to her daily routine in 6 weeks after surgery and at 24-month followup, Modified Crosby and Insall scale was good and Kujala score was 88.
A 70-year-old man had a 5-year history of bilateral knee pain, which had gradually worsened over the last one year, along with reduced walking distance secondary to bilateral osteoarthritis of the knee. He had no difficulty in daily life activities during childhood or adulthood. He had worked as a barber and had no history of trauma. There was no relevant family history. He walked with two crutches since developing bilateral knee pain and could not negotiate stairs. Conservative therapy at another medical clinic, including injection of hyaluronic acid into both knees, was not effective.\nWhen he first visited our institution, physical examination revealed conspicuous bilateral quadriceps atrophy. Both quadriceps were rated as having strength 3 on a muscle testing scale of 0–5. The patellas were palpable at the lateral side of the bilateral femoral condyle and had no mobility during flexion and extension. The proximal tibiae were rotated outward. Preoperatively, the passive range of motion in both knees was −10° to 130°. There was an extension lag of 45° at both knees. Effusions were present in both knees. The knees showed no signs of instability or ligamentous deficiency.\nRoentgenograms and computed tomography (CT) showed patellar dislocation and severe osteoarthritis of the bilateral knees with complete loss of the lateral compartment joint space (Figures –). Valgus deformity of 10° was observed in each knee on standing with the lower extremities aligned. The patient had more pain in the left knee than the right knee. TKA with correction of the extensor mechanism was planned first for the more painful left knee.\nA midline longitudinal skin incision was made under tourniquet control and lateral parapatellar arthrotomy was performed. The patella was located in the lateral gutter of the knee; the femoral condyle was hypoplastic. The medial retinaculum was thin. The vastus medialis oblique muscle was found to be located over the anterior aspect of the femur. For realignment of the extensor mechanism, we performed extensive medial and lateral retinacular release and distal realignment by tibial tubercle transfer. A posterior stabilized prosthesis (NexGen LPS-Flex; Zimmer, Inc., Warsaw, IN) was implanted and held in place with cement. Patellar resurfacing was not performed. The femoral component prosthesis was placed in 9° external rotation with reference to the posterior condyle line to facilitate patellar tracking. The iliotibial tract was partially detached from Gerdy's tubercle subperiosteally. The lateral collateral ligament and the popliteus tendon were also partially released from the lateral femoral condyle. The rotational alignment of the tibial component was based on the locations of the femoral components. After cementing the selected implants, the dislocated patella could not be reduced, so a proximal realignment procedure was performed as described by Insall et al. [], and the rectus femoralis tendon was lengthened by Z-plasty. Thereafter, the patella was in the groove during extension, but passive flexion angle was limited to 90° of flexion of the knee with the hip flexed to 90°. The lateral side of the arthrotomy could not be closed. Medial plication was performed as possible as we could. Finally, the patella could not be reduced fully and did not track centrally, but more laterally, in the patellofemoral groove throughout the full range of movement ().\nFull weight-bearing walking was allowed 7 days postoperatively with a brace for 0° angle restriction for 2 weeks. Range of motion (ROM) exercise using a continuous passive motion device was started 1 week after the operation. At 4 weeks after the operation, ROM was 0°–90° in the left knee and the patient was discharged with one crutch.\nAt 5 weeks after the operation, the patient slipped at home and fractured his left tibia. He was readmitted and conservative therapy was performed with a brace against the fracture. Three months later, his fracture was healed and he was discharged walking with one crutch ().\nOne year after the operation on the left knee, he had hoped to undergo right knee surgery because of pain. He was not satisfied with the restriction of flexion angle of the left knee and was concerned about future fractures. Therefore, he asserted that it was not necessary to reduce the dislocated patella and realign the extensor mechanism in the right knee.\nWe performed TKA using the same prosthesis in the right knee without realignment of the extensor mechanism and reduction of the patella. A midline longitudinal skin incision was made under tourniquet control, and medial parapatellar arthrotomy was performed. The femoral component prosthesis was placed in 3° external rotation with reference to the posterior condyle line. The right patella was located on the lateral side of the femoral component.\nAt the final follow-up one year after the right knee operation, the patient had full extension and 90° flexion in the left knee. There was an extension lag of 45° and flexion angle was 125° in the right knee. Left side quadriceps strength was improved to a rating of 4 on the muscle testing scale of 0–5, but that on the right side was not improved as before surgery. His walking ability was improved and he was satisfied with pain relief in both knees and walked with one crutch ().\nThe preoperative Knee Society score and functional scores were 40 and 15, respectively, which improved to 83 and 60, respectively, at the final follow-up.