Treatment of ischiofemoral impingement: results of diagnostic injections and arthroscopic resection of the lesser trochanter

Abstract

Ischiofemoral impingement (IFI) is an often unrecognized cause of hip pain caused by abnormal contact between the lesser trochanter and the ischium. To date, surgical treatment for those whose pain is not relieved by activity modification and steroid injections has not been defined. This study describes our imaging protocol and reports the results of arthroscopic, lesser trochanteric resections that were performed to treat this condition. Seven patients with symptomatic, MRI-documented IFI had ultrasound injections of ropivicaine and steroid into their ischiofemoral space. The injections provided complete but only transient relief of their groin and buttock pain and thus, all seven ultimately had an arthroscopic resection of their lesser trochanter. All hips were evaluated preoperatively and at 3, 6 and 12 months postoperatively with Byrd's modified Harris hip scoring system. Average age of the seven patients was 46 years and there were five females and one male. Preoperative scores averaged 43 points. After surgery, all patients used crutches for 4-6 weeks, and had 6-week scores that averaged 58 points. The patients and their scores continued to improve and at 6 and 12 months, their scores averaged 86 and 91 points, and none had chronic hip flexor weakness or recurrence of their hip pain or snapping. Arthroscopic iliopsoas tenotomies in combination with a resection of the lesser trochanter will provide complete relief of the painful snapping, groin and buttock pain caused by ischiofemoral impingement.

Fig. 1.

MRI study of the right hip in a patient with the clinical findings of IFI showing Quadratus Femoris muscle edema (arrow head) and narrowing of the ischiofemoral space (arrow) between the ischium and lesser trochanter.

Fig. 2.

The pain ‘circle’ diagram had circles into which patients put an ‘X’ to indicate pain in the following areas: (A) anterior superior spine; (B) lateral greater trochanteric area; (C) central groin; (D) symphysis pubis; (E) proximal inner thigh; (F) anterior thigh; (G) posterior iliac crest; (H) sacroiliac joint; (I) sciatic notch and (J) ischial tuberosity. The circles were placed over anatomic locations commonly associated with hip pain. The patients would place X’s as shown above, to indicate how the anterior groin pain associated with their ischiofemoral impingement radiated posteriorly around the inner thigh to the lower buttock and ischial tuberosity area.

Fig. 3.

(A–C) A fluoroscopic view showing the best position for the proximal cannula which contains the 30º arthroscope (A), and the position of the inferior cannula through which the thermal probe is inserted and advanced until it is visualized at the tip of the cannula (B). The tendon and muscle attachments are removed from the lesser trochanter (C) prior to its resection.

Fig. 4.

(A–D) Fluoroscopic view of the right hip showing the 5.5 mm burr placed on the anterior surface of the lesser trochanter; arthroscopic views (B–C) showing the progressive resection of the lesser trochanter; and a fluoroscopic view (D) demonstrating the completed resection of the lesser trochanter.

Fig. 5.

(A–B) Preop (A) and 6-month postop (B) radiographs showing the complete resection of the lesser trochanter in a 15-year-old high school track athlete. There was no regrowth of bone or heterotrophic ossification at the lesser trochanter at 6 months or on similar films obtained 1 year after surgery. The athlete returned to competition and ran in her state championship, symptom-free 6 months after her hip arthroscopy.