Case report: Osteonecrosis of the femoral head after hip arthroscopy

Abstract

Background: Hip arthroscopy is a common orthopaedic procedure used as a diagnostic and therapeutic tool with a multitude of surgical indications. The complication rate is reportedly between 1.3% and 23.3%. Major complications are related to traction, fluid extravasation, and iatrogenic chondral injury. Although osteonecrosis is a concern with any surgical procedure about the hip, this complication has been primarily a theoretical concern with hip arthroscopy.

Case description: We report the case of a 24-year-old man who presented with a 2-year history of left hip pain. He underwent hip arthroscopy to include débridement of a torn labrum and removal of a prominent pincer lesion for femoroacetabular impingement. Traction was initiated by applying manual traction to the traction bar until 10 mm of joint distraction was obtained. Traction was removed at 90 minutes. At the 3-month followup, MRI showed osteonecrosis in the subcapital region of the left femoral head.

Literature review: It generally is agreed the magnitude and duration of traction during hip arthroscopy increase the risk of traction-related injuries. Only one previous case of femoral head osteonecrosis associated with hip arthroscopy has been reported, and this may have resulted from the initial traumatic event. Based on anatomic studies, the use of standard arthroscopic portals would not put at risk any dominant normal vascular structures supplying the femoral head. In contrast, the literature shows that femoral head osteonecrosis may develop secondary to a combination of increased intraarticular pressure and traction.

Purposes and clinical relevance: We suspect this case of femoral head osteonecrosis after hip arthroscopy was caused by traction used in the procedure.

Fig. 1A–B

Preoperative (A) coronal proton density fat saturation-weighted and (B) sagittal T1-weighted MR images show the femoral head. This noncontrast MRI was performed in March 2008, and shows no evidence of osteonecrosis of the femoral head.

Fig. 2A–B

(A) A preoperative AP radiograph of the pelvis from September 2008 shows evidence of a cross-over sign bilaterally. (B) The postoperative AP radiograph was taken in the recovery room immediately after surgery.

Fig. 3A–B

Postoperative (A) coronal proton density fat saturation-weighted and (B) sagittal T1-weighted MR images show the region of osteonecrosis of the femoral head. This noncontrast MRI was performed in December 2008 and has a heterogeneous, predominately increased, signal in the subcapital region of the left femoral head involving the 10 o’clock to 2 o’clock position on the coronal image (arrow).