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.
A 51-year-old healthy bricklayer male, born in eastern Europe, presented with right-knee pain caused by a fall on the knee during his work, a few weeks prior. During his childhood, a clinically evident bilateral dislocation of patella was observed and described without the assistance of imaging. Nevertheless, the pathology was asymptomatic, and he never reported difficulty in walking. Therefore, the malformation had never been treated and the patient conducted a normal life including time served in the army.\nPhysical examination revealed that the patient could walk normally, with a very mild stumble on the right knee, which was referred as absent before the trauma. There was conspicuous muscle wasting of each thigh (particularly on the medial side, with a clear depression on the vastus medialis) and 15° of genu valgum. The patellae were lying laterally to the lateral femoral condyle with the knee in the position of full extension () and they displaced more laterally during the flexion (). The proximal tibiae were rotated outward. The knees could be extended actively against maximum resistance, with full range of motion. Both the femoral quadriceps worked as knee extensors, and their strength was 5/5. The knees showed no signs of instability or ligamentous deficiency. The right knee was painful on the lateral side, and the clinical signs were positive for pathology of the lateral meniscus.\nRoentgenograms of bilateral knees revealed small, laterally displaced patellae with slight degenerative changes in the tibiofemoral joints with subluxated tibia (). The medial joint spaces were widened. Lateral roentgenograms showed marked lateral rotation deformities of the tibiae (). A skyline view showed an increased deep of the trochlear groove, with laterally dislocated patellae forming a sort of new joint with the lateral aspect of the condyle ().\nMagnetic resonance imaging (MRI) showed a lesion with dislocation of the lateral meniscus on the right knee. On both sides, the MRI confirmed the dislocation of the patellae, a severe hypoplasia of the medial side of the femoral quadriceps, and an external rotation of the proximal tibia particularly evident on the tibial tuberosity ().\nIn order to identify a possible aetiology of the malformation, the patient underwent electromyography/electroneurography, which showed normal function of all the separate portions of the quadriceps muscles thus not explaining the origin of this malformation.\nThe clinical and the imaging findings suggested a lesion of the lateral meniscus as the probable cause of the pain. Therefore, we performed a knee arthroscopy, whose intraoperative findings confirmed the MRI. During the surgery, we performed just a selective arthroscopic meniscectomy.\nAfter the operation, the patient followed a simple protocol of rehabilitation: 15 days of relative rest with partial bearing and low-molecular-weight heparin therapy, then progressive full recover of activities. Quickly, the knee showed satisfactory improvement, with no pain in walking and a complete range of motion, as before the operation, and comparable to the other knee.\nDuring the last clinical evaluation, 12 months after surgery, written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.