OSTEOCHONDRAL FRACTURES OF THE LATERAL FE MORAL CONDYLE ASSOCIATED WITH TRAUMATIC PATELLAR DISLOCATION RESULTING FROM SPORT INJURY IN CHILDREN

Purpose of the study Nineteen osteochondral fractures of the lateral f emoral condyle associated with acute traumatic patellar dislocation re sulting from sport injury in children were studied. The purpose of thi s study was to specify clinical and radiological features. Material an d method This study was led with special care to injury circumtances, fracture visibility on X-rays, size and location of the fracture, trea tment delay, presence of femoro-patellar dysplasia signs. Treatment re sults were evaluated on knee pain, bone consolidation and recurrent di slocation. Result Thirteen boys and six girls aged 8 to 16 years (aver age 14 years) were included. The injury resulted from a rotatory-compr ession stress in 75 per cent cases. The patella was always in place at the time of examination. Thirteen fractures were diagnosed within 24 hours and 5 fractures were diagnosed within 1 week after injury. One f racture was not visible on X-rays and was diagnosed 6 weeks after inju ry. Only the lateral view showed the fracture in more than one case ou t of two. Seven patients whose fracture was less than 5 mm. or involvi ng a non-weight-bearing portion, or diagnosed within more than ten day s after injury, were treated by knee arthroscopy and removal of the os teochondral fragment. Twelve patients were treated by arthrotomy and e xcision (one case) or replacement of the osteochondral fragment (11 ca ses). The replaced fracture was fixed with biological glue ten times, and screwed once. The knee was immobilised in a cylinder cast and weig ht-bearing prohibited for six weeks. Bone consolidation was obtained i n 9 cases out of 11, in an average of 8 weeks. Knee pain occured 5 tim es. Recurrence of the dislocation occured 3 times within 6 months. Eig hty per cent of these children showed patello-femoral dysplasia. Discu ssion This fracture complicated 31.6 per cent of traumatic patellar di slocation resulting from sport injury in children which we observed du ring the last ten years. It may be overlooked if it is suspected and c arefully looked for by radiographic examination including antero-poste rior, lateral, oblique and true skyline views of the patella. The pres ence of fat in the hemarthrosis may help. Early surgery is recommended . Arthroscopy may be performed to evaluate fracture location and size. After ten days, host area begins to fill in and free fragment will no t fit back well. Fragments less than 5 mm, or involving a non-weight-b earing portion, or diagnosed within more than ten days after injury, m ay be removed. Conclusion Lateral femoral condyle osteochondral fractu res are associated with nearly one third of traumatic patellar disloca tion resulting from sport injury in children. A detailed radiographic examination can help diagnosis. Treatment depends on the delay after i njury, the size and location of the fracture.