An 18-year-old girl presented to us with recurrent dislocation of patella. She had two previous surgeries, first one at the age of 16 years and the second surgery a year later, in two different hospitals. Lateral release and medial plication was done in 2007 and extensive lateral release and vastus medialis advancement was done in 2008. Unfortunately, the problem persisted and the patella continued to dislocate when she presented to us. On clinical and radiological examination, she had generalized ligamentous laxity, apprehension test was positive and the medial patellar glide was <1/4, indicating a tight lateral retinaculum. Tibial tubercle- trochlear groove (TT-TG) distance, a measure of Quadriceps angle by CT scan was 23.2 mm. Patella alta measurement by Caton Deschamps's index was 1.2. CT showed Patellar tilt angle of 43 degrees, Type ‘C’ Dejour's trochlear dysplasia ie. lateral femoral convexity and medial femoral hypoplasia [Figures –].\nShe underwent sulcus deepening trochleoplasty as described by Dejour and medial patellofemoral ligament (MPFL) reconstruction along with lateral retinacular release. Through a midline skin incision and medial parapatellar arthrotomy, the trochlea was exposed under tourniquet control. The peritrochlear periosteum and synovium were incised about 5 mm from the trochlear cartilage margin. This width of 5 mm of the bone will correspond to the prominence of the trochlea (distance between the anterior cortex of the femur and the boundary of the trochlear cartilage). The cortex was osteotomized in the same plane and an osteochondral flap of about 5 mm thick was raised in “V” shape. The trochlear sulcus was referenced off the intercondylar notch, and was mapped proximally and 6° laterally. A thin layer of cancellous bone was removed with a curette up to the notch, more in the middle of the trochlea. The trochlear bone shell was impacted into the trough created in the cancellous bone. However, the sulcus formed was not deep enough. Hence, to achieve sufficient correction, we split the cartilage along the center of the groove. The newly established trochlea was fixed with two small staples astride the osteochondral junction, one on either side of the groove. There was no impingement as the knee was taken through its range of motion. The peritrochlear periosteum and the synovium were sutured.\nAfter this procedure, we reconstructed the MPFL, as described by Erasmus, but with a few variations. A double-looped semitendinosus tendon was anchored to the medial border of patella at the junction of upper and middle thirds, typically where the perimeter of patella becomes more vertical with a titanium anchor. A tunnel was drilled at the isometric point on the medial femoral epicondyle through which the tendon was pulled through and was fixed with a biodegradable interference screw []. Medial patellar retinaculum was repaired at this ligament. Lateral retinacular release was done from inside out prior to the reconstruction of medial patella ligament since medial patellar glide was restricted in our patient. Since the new trochlear groove was angled at 6° laterally, distal realignment by tibial tubercle osteotomy was not done.\nA hinged knee brace to allow 30° flexion was used for 3 weeks. Daily knee flexion exercises were allowed. Weight bearing was allowed from the first day using crutches.\nOne year following the surgery, she had slight medial parapatellar tenderness and no patellar apprehension. Presently, terminal 5° of flexion is restricted. Radiological signs of trochlear dysplasia were corrected and patellar tilt angle improved from 48° to 18° . Kujala score improved from 52 to 80 points. Staples were removed 1 year after surgery. Near-normal looking trochlea surface was seen in postoperative computed tomography (CT) scan and during arthroscopy [].
A 50-year-old woman presented with iatrogenic habitual dislocation of left patella from childhood and pain from past 3 years. She recalled a childhood surgery over middle third of left thigh (incision and drainage). Few years after the surgery, she started noticing the giving way of patella and lived for 38 years without much disability. She was carrying out her daily activities without much pain or symptoms, but she was never symptom free during this period.\nPhysical examination did not reveal general joint laxity or malalignment of the lower extremity. There was a healed surgical scar over middle and lower third lateral aspect of the left thigh. Although the patella was in the femoral trochlear groove in extension, it dislocated laterally with 25 degrees of knee flexion. She complained slight discomfort by an apprehension test, but was not very painful even when dislocated. The passive lateral patellar tilt test was negative since the soft tissue attachment to the lateral border of the patella was diffusely stiff and tight. Radiological examination revealed evidence of patella alta as defined by Insall and Salvati,[] and Q angle was 18 degrees. Clinically and radiologically (Grade III Kellgren and Lawrence classification[]) tricompartmental degenerative knee arthritis was appreciated []. Preoperative Kujala score[] was 49.\nWith patient in supine position under epidural anesthesia, an anterior midline knee incision was used with paramedian arthrotomy. The lateral retinaculum was thickened while the medial retinaculum was thinned. The lateral tether is released by dividing the fibrous adhesions, which extended along the lateral intermuscular septum. The lateral patellar retinaculum and the synovium were divided and vastus lateralis was detached from the quadriceps tendon, leaving a rim of tendon for suturing.\nDue to shortening of the extensor mechanism, the patella could not be reduced. Quadriceps tendon was lengthened using V Y plasty at aponeurotic junction. Tracking was augmented with MPFL reconstruction using semi-tendinosus tendon and patellar end was fixed with 2.8 mm FASTak titanium anchor on the medial border of patella and over near isometric point on medial epicondyle of femur, which was checked under fluoroscopy. Patellar maltracking was persistent and so, it was decided to proceed with medial and distal transfer of tibial tuberosity.\nA long-leg hinged knee brace was applied with the knee in 20° of flexion and partial weight bearing with crutches for four weeks was advised, during which the patient was encouraged to do vigorous static quadriceps strengthening exercises. Knee mobilization and full weight bearing was started after four weeks. Initially patient had extensor lag of 15 degrees as she was immobilized in flexion. But after vigorous quadriceps exercises, patient improved without any extensor lag.\nAt final followup two years postoperatively, the patient was pain-free. There was no evidence of patellar maltracking or instability on detailed physical examination. Radiographs showed well reduced patella in both lateral, anteroposterior view and skyline view []. The patient's kujala knee society score 89 [] and range of motion was 0° to 90° on the left side []. Quadriceps strength was rated 4 (MRC grade).