Hip pain that travels distal to the knee has been thought to be related to lumbar spine pathology; however, in one study of patients with osteoarthritis scheduled to undergo primary total hip arthroplasty (THA), 47% of patients had pain radiating below the knee ¹⁾.

The authors felt this may stem from referral along the saphenous branch of the femoral nerve, which innervatesthe hip joint. Lesher et al ²⁾ described 12 pain distributions after obtaining pain diagrams of patients with degenerative hip disease. Traditional groin pain and buttock pain was seen in 55% and 71% of patients, respectively. Pain distal to the knee was seen in 22% of patients, and 2% of patients described pain occurring as distal as the foot.

Extra-articular hip pain sources have traditionally been characterized as follows:

iliopsoas tendonitis produces anterior groin pain, trochanteric bursitis causes lateral pain, adductor strains create medial thigh pain, and piriformis syndrome evokes posterior pain. However, it is important to realize that intra- and extra-articular hip pain cannot always be determined based on pain patterns, and in many patients they coexist.