Received Aug 18; Accepted Sep Published by Elsevier B. All rights reserved. This article has been cited by other articles in PMC. Abstract Habitual dislocation of patella is a condition where the patella dislocates whenever the knee is flexed and spontaneously relocates with extension of the knee.
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Corresponding author. This article has been cited by other articles in PMC. Abstract Habitual dislocation of patella is a rare disorder. Sometimes it is associated with angular deformity such as genu valgum. We experienced habitual patella dislocation associated with genu valgum that was treated with corrective osteotomy of distal femur and soft tissue realignment procedure including lateral release and medial reefing.
Keywords: Habitual patella dislocation, Genu valgum, Distal femoral osteotomy Introduction Habitual patellar dislocation is a rare condition where the patella dislocates during flexion and relocates during extension unlike chronic patellar dislocation that occurs during both flexion and extension of the knee, and it usually presents without pain or swelling.
A variety of surgical techniques have been introduced for the treatment of habitual dislocation of the patella with genu valgum. Among them, osteotomy combined with proximal soft tissue realignment procedures including lateral release and medial reefing has been commonly performed.
It has been known that significant treatment results can be obtained with combined procedures, not with a single procedure. We here report a case of habitual dislocation of the patella with genu valgum treated with a corrective osteotomy of the distal femur combined with lateral release and medial reefing. The clinical and radiological outcomes of the treatment were satisfactory.
Case Report A year-old man visited our institution due to lateral dislocation of the left knee in flexion and instability that had persisted for 7 years Fig. The patient had a history of femoral growth plate fracture treated conservatively at 13 years of age. In the physical examination, the apprehension test was positive. In the radiographic examination, the congruence angle, sulcus angle, Q-angle, and Insall-salvati Ratio was A skyline view of the knee showed lateral dislocation of the patella.
Arthroscopic examination revealed the hypoplasia of the lateral femoral condyle, Outerbridge grade II cartilage damage on the lateral articular surface, and contracture of the lateral retinaculum and vastus lateralis. Patellar dislocation during flexion was confirmed with arthroscopy. A lateral retinacular release and an open-wedge distal fermoral varus osteotomy were followed by additional procedures including lateral release and medial reefing because dislocation was still present after the osteotomy.
About 2 cm of the medial retinaculum was reefed because it was excessively elongated. When lateral dislocation of the patella in flexion was no longer observed, a bone graft was inserted into the osteotomy site. Gradual flexion exercises were started postoperatively. Complete flexion was obtained at the 3rd postoperative week. Weight bearing was gradually permitted and complete weight bearing was allowed at the 3rd postoperative month.
A direct impact that knocks the patella out of joint A twisting motion of the knee, or ankle A sudden lateral cut  Anatomy of the knee[ edit ] The patella is a triangular sesamoid bone which is embedded in tendon. It rests in the patellofemoral groove, an articular cartilage -lined hollow at the end of the thigh bone femur where the thigh bone meets the shin bone tibia. Several ligaments and tendons hold the patella in place and allow it to move up and down the patellofemoral groove when the leg bends. The top of the patella attaches to the quadriceps muscle via the quadriceps tendon ,  the middle to the vastus medialis obliquus and vastus lateralis muscles, and the bottom to the head of the tibia tibial tuberosity via the patellar tendon , which is a continuation of the quadriceps femoris tendon. Finally, the lateral collateral ligament and the medial collateral ligament stabilize the patella on either side. Diagnosis[ edit ] Patellar dislocation To assess the knee, a clinician can perform the patellar apprehension test by moving the patella back and forth while the people flexes the knee at approximately 30 degrees. A patella that slips laterally on early flexion is called the J sign, and indicates imbalance between the VMO and lateral structures.
Habitual dislocation of patella: A review