The patient was an otherwise healthy 15-year-old male who presented 3.5 weeks after a motor vehicle accident in which he sustained a right posterior hip dislocation and cervical spine injury. He was a restrained, front-seat passenger in a vehicle which lost control off of the road at a speed of approximately 65 miles h−1. He lost consciousness and was taken to the emergency department where he was diagnosed with C2–C4 spine fractures and a posterior right hip dislocation. There was no neurological injury. His hip was reduced in the operating room, at which time a tibial traction pin was placed. After presentation (1 week), he underwent a C2–C4 cervical fusion. Prior to discharge, the tibial traction pin was removed and he was kept non-weight-bearing on his right lower extremity. Plain radiographs, CT scan, and MRI confirmed the presence of loose fragments in the joint, a slightly displaced osteochondral fracture of the weight-bearing aspect of the femoral head with depression of the articular surface, and areas of full-thickness cartilage loss (Figs. and ).
A preoperative AP radiograph of the pelvis demonstrating no appreciable abnormality in the contour of the femoral head
A sagittal section of the patient’s MRI demonstrating an area of full-thickness cartilage loss in the anterior-superior weight-bearing zone of the femoral head
The patient presented to our clinic approximately 1 month after his initial injury. After the traumatic posterior dislocation (5.5 weeks), the patient underwent a right hip surgical dislocation with fixation of the osteochondral defect and osteochondral autograft transplantation from the ipsilateral knee to the femoral head. Surgical exposure was performed using a Kocher–Langenbeck incision [13
], followed by a surgical hip dislocation with a trochanteric osteotomy [12
] (Fig. ). The hip was dislocated anteriorly, and a 3
3 cm defect where the cartilage had been impacted into the femoral head was visualized (Fig. ). While there was a stable component to the cartilage, there was an area in the anterior-superior weight-bearing region with exposed subchondral bone where the cartilage was completely absent. Several loose fragments within the capsule were identified and excised, and all cartilage fragments were removed from the joint. No significant acetabular cartilage or labral pathology was appreciated. At this point, the cartilage injury on the femoral head was debrided back to stable ridges. The stable osteochondral lesion appeared well perfused, as significant bleeding was appreciated from the subchondral surface. While the chondral lesion was slightly rotated, the contour of its borders still matched that of the neighboring cartilage. Therefore, the decision was made to stabilize the lesion with bioabsorbable SmartNails (ConMed Linvatec, Largo, FL, USA), each 1.5 mm
2 cm in length, placed around the periphery. Initially, two of the SmartNails were utilized to lock the lesion into a stabilized position, away from the neighboring cartilage defect.
Intraoperative images demonstrating the trochanteric osteotomy (a) and exposure of the femoral head (b) prior to dislocating the femoral head anteriorly
An intraoperative image demonstrating cartilage impaction along with exposed subchondral bone in the anterior-superior portion of the femoral head
Focus was then directed to the full-thickness cartilage defect in the anterior-superior weight-bearing zone of the femoral head, adjacent to the stabilized osteochondral defect. There was a linear lesion that measured approximately 2 cm in length and was tapered down from approximately 8 to 5 mm in width. It was felt that three osteochondral plugs would be required upon sizing, and the recipient site was prepared using the Arthrex osteochondral autograft transplant system (Arthrex, Naples, FL, USA). Next, a small lateral arthrotomy was performed at the level of the knee joint approximately 3 cm in length. Three osteochondral plugs were harvested using the Arthrex osteochondral autograft transplant harvesting system—8, 7, and 5 mm in size, respectively.
The donor osteochondral plugs were then transplanted to the area of full-thickness cartilage loss adjacent to the stabilized osteochondral defect. The 8-mm plug was placed most superiorly, followed by the 7-mm plug, then the 5-mm plug. Good contour of the articular cartilage surface and to the neighboring osteochondral defect was obtained. A third SmartNail was then used to fix the ostechondral defect (Fig. ). A smooth articular contour was achieved after placement of the osteochondral plugs. At the completion of the procedure there were some areas of residual cartilage injury with residual exposed bone at the level of the fovea and also inferiorly in the non-weight-bearing region of the joint. As these foci were not in weight-bearing regions, cartilage transplant was not believed to be necessary, but microfracture procedures were performed to stimulate fibrocartilage in-growth. Of note, consistent bleeding from the femoral head was appreciated throughout the procedure. The donor autograft sites were then back filled with OBI plugs (Osteobiologics Inc., San Antonio, TX, USA), where again, a smooth contour was achieved with the neighboring cartilage.
An intraoperative image of the femoral head after placement of the donor osteochondral plugs and three SmartNails
Post-operatively, the patient was kept non-weight-bearing for 6 weeks and then progressed to weight-bearing as tolerated. At 12 weeks post-operatively, the patient was ambulating with the use of a cane without any pain, had minimal symptoms, and plain radiographs demonstrated an overall reasonable contour of the femoral head and good preservation of the joint space (Fig. ). An MRI performed at 24 weeks post-operatively demonstrated well-incorporated autograft plugs and intact cartilage over the plugs with smooth interfaces with the remaining bone. Thinning of cartilage and moderate bony irregularity was noted anteriorly related to the fracture, but no reactive signal underlying the bone was present. At 1 year follow-up, the patient has no complaints of pain, good mechanics with ambulation, and has returned to running and physical activity without difficulty.
A postoperative AP radiograph of the patient’s pelvis demonstrating an anatomic contour of the femoral head and well-preserved joint space