ePoster #709 - ISHA Annual Scientific Meeting 2016

Osteoid Osteoma Of The Hip: A Unique Source Of Impingement

Andrea Spiker, MD, New York, NY UNITED STATES
Ben-Zion Rotter, BS, New York, NY UNITED STATES
Douglas Mintz, MD, New York, NY UNITED STATES
Bryan Talmadge Kelly, MD, New York, NY UNITED STATES

Hospital for Special Surgery, New York, New York, UNITED STATES

FDA Status Cleared

Summary: We present the largest case series of osteoid osteoma of the hip and describe patient reported outcomes after treatment of this lesion.

Introduction: Femoroacetabular impingement (FAI) is more frequently identified as the etiology of hip pain. There are instances when FAI can be due to, or confounded by, a separate process in the hip joint. One relatively uncommon but treatable cause is an intra-articular osteoid osteoma (IAOO) of the hip. While there are multiple case reports of osteoid osteoma in the hip, we present the largest case series of hip IAOO and discuss patient reported outcomes after treatment with hip arthroscopy.

Methods: We identified all patients in our institution’s preservation group who had IAOO of the hip. We classified lesion location and hip radiographic measurements, and analyzed patient reported outcome scores when available, including the modified Harris Hip Score (mHHS), the International Hip Outcome Tool-33 (iHot33), Hip Outcome Score-Activities of Daily Living and -Sport Specific (HOS-ADL and HOS-SS).

Results: 40 patients with confirmed IAOO were identified. 30 of these patients underwent intervention at our institution. 16 had radiofrequency ablation (RFA), 13 had hip arthroscopy, 1 had open excision.

The average pre-operative radiographic measurements were: alpha angle 64.6 o, acetabular version at 1 o’clock, 2 o’clock and 3 o’clock of 3 o, 8.8 o and 16 o, respectively; coronal center edge angle 30.2o and femoral neck-shaft angle 133.2 o.

Of the 11 treated with hip arthroscopy, we found significant improvements in mHHS, HOS-ADL, and iHot33 scores. Compared to patients undergoing hip arthroscopy for FAI alone, baseline mHHS, HOS-ADL, HOS-SS and iHot-33 scores were almost identical.

Discussion/Conclusion: This is the largest case series of intra-articular hip osteoid osteomas. We have found that arthroscopic treatment of intra-articular hip osteoid osteomas results in good clinical outcomes and is a viable alternative to RFA, which can damage articular cartilage of the hip, and the standard open surgical excision, which is more invasive and requires a longer recovery.