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 [].
The patient was a 49-year-old Caucasian male with body mass index of 27 kg/m2. He complained about pain on his right knee in the last 8 months. The pain was gradually increased and still could be relieved by rest. He had the history of fixed lateral patellar dislocation since 25 years before. The dislocation happened after he got slipped and his right knee hit the floor with the body on top/kneeling. He came into the examination room with antalgic gait without any walking aid. He felt that his right knee was giving away while walking. There was no other trauma. There were no history of medical and surgical treatment, no family with the same symptom, and no routine sport activity.\nMuscle atrophy could be seen on the anterior compartment of the thigh, specifically on the lateral medial and intermedius muscle. We observed the atrophy of the thigh muscle from the anterior, lateral, and posterior view (). We found the patella was laterally dislocated. The knee range of motion was 0-120° in both passive and active movements. The patellar apprehension test was positive while the other special tests such as anterior and posterior drawer test, patellar tap test, joint line tenderness test, and Lachman test were all negative.\nOn the AP view of the radiographic imaging, we found neither varus nor valgus deformity of the knee and no sclerosis at the subchondral bone. However, whole mechanical axis radiology was not possible to be performed at the time of examination; therefore, we are lacking data such as femoral anteversion and Q angle. There was no sign of secondary osteoarthritis of the knee joint. From the lateral view, there was no sign of patella alta and patella baja, but on the skyline view, we could see that there was a lateral dislocation of the knee. The trochlear groove was relatively normal (). From the physical and X-ray examination, the patient was diagnosed as having chronically fixed lateral patella dislocation of the right knee.\nWe decided to perform extensive lateral release and right medial patellofemoral ligament reconstruction for this case. We performed incision on the lateral side of the knee joint until we reached the lateral capsule. We decided to release the lateral capsule and try to reduce the patella to be in the midline position. The patella was laterally fixed because of the tightened lateral vastus. We extended the incision and performed lateral release by cutting the fascia of the lateral vastus. After that, we tried again to reduce the patella but there was still resistance. We then cut the fascia of the medial vastus until the dislocated patella was fully released (). After we successfully reduced the patella, we performed semitendinosus tendon graft harvesting.\nA 3 cm oblique skin incision was made at the medial proximal tibial area, and the soft tissue was released. The semitendinosus tendon was harvested using a tendon stripper. We made a double-stranded graft by folding the semitendinosus tendon. The graft length was 160 mm, and the diameter of the ST tendon was 7 mm. After preparing the graft, 3 cm longitudinal skin incisions were made at the patellar and femoral natural footprints of the MPFL, and the soft tissue was peeled off so that the graft could pass through the soft tissue tunnel smoothly.\nA patellar tunnel was made at the one-third of the superior part of the patella from the medial side until it reached the lateral side. Subsequently, the graft was passed through the bone tunnel of the patella. After the endobutton (Smith & Nephew, Andover, MA) reached the lateral side, it was flipped to fixate the graft end.\nA femoral bone tunnel was constructed at the MPFL anatomical footprint, which is located at the Schottle point []. A 2.4 mm guide wire was inserted in the medial, ventral, and slightly proximal direction to avoid vessel and nerve injury. A 7 mm drill was used to create a bone tunnel. The depth of the bone tunnel was 80 mm until it reached the lateral cortex of the femur. We then sutured the graft end with ETHIBOND (Ethicon, Somerville, NJ) no. 2 and passed the graft through a medial side of the femur until the end of the tendon coming out from the lateral femoral side ().\nWe then drilled the lateral side of the distal femur and put a cancellous screw and washer with a diameter of 4.5 and a length of 65 mm just above the femoral tunnel. The end of the graft was sutured with ETHIBOND, and the ETHIBOND suture was then anchored to the cancellous screw and washer as the fixation of the patella to prevent it from redislocation ().\nThe soft tissue was then closed in layers. After that, we did confirmation X-ray to confirm the position of the inserted screw at the lateral side of the distal femur (). For the rehabilitation program, at first, the knee brace was applied to keep the knee in a full-extension position. The brace was used in this position up to three weeks; then, the knee flexion was increased to 20 degrees every week. After eight weeks postsurgery, the brace could be discharged and the patient could start active motion of the knee.