Exercise-induced stress injuries to the femur.

Seventy-one athletes with 74 stress injuries to the femur were studied using a case-controlled design. Forty-three were females (26.6 yrs) and 28 were males (31.2 yrs). Each patient had exercise-induced pain in the hip, groin or thigh and a Tec-99m-MDP bone scan showing focal uptake of radionuclide in the femur. Running was the most common activity at the time of injury (89.2%) followed by triathlon (4.6%) and aerobic dance (4.6%). Thirty per cent of the runners had increased their training duration immediately prior to their first symptom. Anterior thigh pain was the most frequent site of exercise-induced pain (45.9%) followed by hip pain (27%) and groin pain (8.1%). During the clinical examination, when asked to hop on the affected limb, 70.3% of the patients had pain reproduced in the hip, groin or anterior thigh. There were 39 cases (53%) involving focal uptake of radionuclide in the femoral shaft, 15 (20%) in the lesser trochanter, 11 (15%) in the intertrochanteric region between the femoral neck and the greater trochanter, 8 (11%) in the femoral neck and 1 (1%) in the greater trochanter. Two patients suffered displaced fractures, one at the femoral neck and the other in the shaft of the femur. Neither patient had previously sought medical attention for their leg pain. Of 46 plain radiographs taken, only 11 (24%) were abnormal. The mean time to diagnosis and recovery were 6.6 and 10.4 weeks respectively. Substitution of cycling and water exercise for running were the most common therapeutic interventions.