Abstract
Post-traumatic avascular necrosis of the femoral head usually occurs after hip dislocation and femoral neck fracture. Recently along the development of hip arthroscopy, early stage of avascular necrosis of the femoral head can be treated rthroscopically. We hereby present two cases of post-traumatic avascular necrosis patients treated with hip arthroscopy.
Case 1
Twenty one year old female patient came to the hospital because of fall from height of 3 floors. Left acetabular fracture, both superior pubic rami fractures and severely displaced left femoral neck fracture were identified at the emergency department (Fig. 1-A). She underwent surgery at the injury day. After the repair of ruptured urinary bladder, internal fixation of the femoral neck was done. Four cannulated screws with washers were inserted for displaced femoral neck fracture, consistent with garden stage IV (Fig. 1-B). Skeletal traction of ipsilateral lower extremity was applied four weeks after the surgery for acetabular fracture. She visited us for painful limitation of motion on left hip at eight months postoperatively. Plain radiograph showed collapse of femoral head and osteophyte formation which were caused by post-traumatic avascular necrosis (Fig. 1-C,D). Femoral head was perforated by a screw. She was planned to remove the screw and resect the osteophyte arthroscopically. On arthroscopic examination, severe synovitis and folded, collapsed femoral cartilage were identified (Fig. 1-E). Screws were removed and osteophyte were also resected (Fig. 1-F). We filled the cavity caused by the screws with allogenic strut graft for structural support. After the surgery, pain was relieved and she came back to her active daily living and for six months, no other complication nor further collapse were identified postoperatively.
Case 2
Fourty year old male patient was admitted to the hospital for fall from height about fifteen feet from the ground. Left femoral neck fracture was identified on the emergency department. Previously he had underwent intramedullary nailing for the femoral shaft fracture about five years ago. Urgent internal fixation with four cannulated screws was done on the day of injury. The fixation was unsatisfactory because previously inserted intramedullary nail hindered the proper trajectory of screws. Furthermore, direction of cephalad interlocking holes of the nail were not consistent with the anteversion of femoral neck, we could not place the screws through the nail. Four months after the index surgery, collapse of femoral head and loosening of screws have occurred. MRI showed the collapse of femoral head and posttraumatic avascular necrosis. Prominent bony beak of femoral neck were identified and he complained difficulty and pain on his hip during abduction. We left two screws for secure fixation and resected the bony beak using arthroscopic burr. After the surgery, he felt free from the pain on abduction of hip.
Discussion
Even though collapse of the femoral head is identified, early intervention by the arthroscopy could minimize pain or delay the progression of arthritic change. Authors think that it might be helpful for the young adult patients in terms of pain relief and potential delay of the total hip arthroplasty.
