A 48-year-old male visited Department of Orthopedic Surgery, Chungnam National University Hospital complaining of right anterior thigh pain beginning six months prior without any history of trauma. He had begun having pain in the right inguinal area and difficulty in crossing his legs on the floor beginning six months earlier, and the pain had intensified over that period. He had no other medical issues and had been exercising regularly for over 10 years. On the first visit, physical examination indicated impingement and a simple X-ray revealed sclerotic changes on the right acetabular rim (center-edge [CE] angle of Wiberg, 30°; sourcil angle of Tönnis, 2.1°; Tönnis classification Grade I). Computed tomography and magnetic resonance images showed a partial tear of the ligamentum teres, a central acetabular osteophyte, a spur on the articular surface of the inferior margin of the femoral head/neck junction, and a 1.6×1.5×1.8 cm subchondral cystic lesion on the anterosuperior acetabulum (Fig. 1). Surgical treatments were performed after the six-month drug therapy which did not improve symptoms. Arthroscopic investigation revealed a partial tear of the ligamentum teres, labral tear and a subchondral fibrocartilagenous cystic lesion on the acetabulum.

Thus, ligamentum teres was managed by shrinkage and the labrum was re-fixed in the central compartment, and femoroplasty and acetabuloplasty (osteoplasty) were performed in the peripheral compartment. A C-arm image intensifier was then used to locate the cyst and using an awl, a hole was made on the cyst cover and the yellowish fluid inside the cyst was drained. Microfracture was carried out on the inner-surface of the cyst. Under arthroscopic guidance, the silicon drain tube was used to implant the allogeneic bone graft, which was extruded using a rod and into the cyst (Fig. 2). The patient was discharged 3 days after surgery and allowed to walk on crutches (so that only half the body weight was supported by the repaired hip) for the first 6 weeks after surgery, with gradual progression to full weight bearing thereafter. At 18 months post-surgery, the patient experiences only mild intermittent hip pain and modified Harris Hip Score (mHHS) was improved from 37 to 87, and visual analogue scale (VAS) score has decreased from 7 (before surgery) to 1. By radiology at last follow-up, the grafted bone was well maintained at its initial location and the graft was consolidating with the surrounding bone.

A 49-year-old female visited Department of Orthopedic Surgery, Chungnam National University Hospital complaining of right inguinal pain without any trauma history. She was a teacher and did not regularly engage in athletic activity. Her pain increased despite three months of treatment. On the initial visit, physical examination confirmed severe tenderness on the greater trochanter and positive sign of anterior impingement test. Radiology revealed mild hip dysplasia and multiple cystic lesions on the right anterior rim of acetabulum to the anterioinferior iliac spine (CE angle of Wiberg, 22°; sourcil angle of Tönnis, 8.8°; Tönnis classification Grade I). Surgical treatments were performed after the three-month drug therapy which did not improve the symptoms. Arthroscopy revealed a labral tear, a subchondral cyst of the acetabulum, and bone protrusion. Thus, femoroplasty and labral refixation were performed, followed by curettage and allogeneic bone graft as described for Case 1 (Fig. 3). 16 months post-surgery, some pain remains, but the patient's condition is improved relative to that before surgery. The mHHS improved from 56 to 75, VAS score has decreased from 7 (before surgery) to 3. And by radiography, the grafted bone was well maintained at its initial location.