Background: Congenital dislocation of the patella can cause significant functional disability and is often associated with limb deformity in childhood. Two types or clinical manifestations of this condition have been previously described, namely the fixed lateral dislocation and the habitual or obligatory dislocation of the patella. Few surgical procedures have been suggested for the treatment of the complex condition.

Objective: We reviewed our surgical approach in ten knees (seven children) with both types of patellar dislocation, and evaluated the clinical and functional outcomes.

Methods: All our patients underwent an extensive sub-periosteal mobilization of the extensor mechanism from the lateral side of the thigh combined anteriorly with plication of the medial patellar retinaculum. This procedure was supplemented by medialization of half of patellar tendon in the skeletally immature patients, and by tibial tuberosity transfer that was performed in one skeletally mature patient.

Results: In six children, patellar dislocation was a part of a diagnosed syndrome, namely Down (3 patients), Larsen (1 patient), Rubinstein-Taybi (1 patient) and fibular hemimelia (1 patient). Six knees had fixed type and four (all Down syndrome) had obligatory type of patellar dislocation. Average age at surgery was 9.5 years (range 3.5–14) and the mean follow-up period was 19 months (range 7–33). There was no recurrence during the follow-up period. Two children with Down syndrome, who had flexion contraction and were non-ambulatory, began to walk three months and five months after the surgery. A significant resolution of the valgus deformities was obtained in the operated knees. Two complications were recorded, an undisplaced supracondylar fracture following removal of plastic cast and transitory peroneal nerve palsy.

Conclusions: Abnormal anatomical muscular and bony changes, soft tissue structural changes and limb alignment contribute to patellar dislocation and to subsequent clinical deterioration and deformity progression. Our surgical intervention aimed to realign the extensor mechanism and was effective in treating both types of congenital dislocation of the patella. Based on our experience, the long-standing habitual dislocation is accompanied by changes in the extensor mechanism of the knee that are similar to those occurring in the fixed patellar dislocation and therefore should be addressed surgically in a similar manner.

We believe that soft tissue release and articulated hip distraction distinguishes itself in the short term as a good salvage procedure for late onset severe Perthes disease of the hip.

Our series is made of 10 patients with late onset Perthes disease. All 10 patients were above 9 years of age at diagnosis (average = 11 years). There were 7 boys and 3 girls in the series. All patients had significant limp and pain with positive Trendelenburg sign. All patients used crutches or wheelchairs and had symptoms for a period of 0.5 to 3 years before the operation; all hips had limited ROM. Two patients had previous soft tissue release. There were 2 children with Down syndrome and 1 child had Gleophysic Dysplasia. On preoperative radiographs, 8 patients had a saddle shape subluxating femoral head with hinge abduction and 2 subluxations only. Nine hips were graded Catterall IV and Herring C and 1 hip Catterall III Herring B. There were at least 3 and mostly 4 Catterall prognostic risk signs for these hips. All patients had a broken Shenton line, increased medial joint distance and low Epiphyseal index before surgery.

After adductor and ileopsoas release an orthofix hinged apparatus for distraction is applied to the hip. The distraction continues until overcorrecting of Shenton line achieved. The external fixator is left in place for 4–5 months while in the apparatus flexion and extension of the hip is possible and encouraged. The follow-up ranged from 0.5 to 3 years. At last follow-up all patients were walking freely with improved hip ROM. All patients resumed daily ambulatory status and 2 were involved in regular sports. Latest radiographs showed that the saddle shape disappeared in 7 of 8 hips, in all patients hip subluxation decreased as measured by medial joint distance and Shenton line was corrected to between 0.6 mm. The Epiphysis index and joint congruency improved in most cases.

The level of satisfaction from the operation was very high for all patients and their parents.

Drawing of final conclusion will be possible only after assessing the long-term results.