Girl with left hip pain, mechanical symptoms
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A healthy 15-year-old girl presented with a 1-year history of left hip pain that worsened with activity. Her discomfort occurred primarily during cheerleading. Her pain was predominantly in the groin. She complained of painful catching and, at times, a locking sensation in the hip joint. She denied night pain and rest pain. Prior to presentation, she underwent physical therapy and chiropractic care without relief.
Hip range of motion was symmetric with flexion to 120°, internal rotation to 30°, external rotation to 50°, abduction to 40° and adduction to 20°. She demonstrated pain with left hip range of motion with positive flexion, anterior and abduction impingement signs.
Radiographs demonstrated a heterogeneous sclerotic process of the left innominate bone, primarily involving the ilium, acetabulum and, to a lesser degree, the ischium (Figure 1).
What is the next step in workup of this patient?
Advanced imaging and guided biopsy
CT pelvis showed the areas of sclerosis on the radiographs were due to a markedly dense sclerotic process involving the cortex of the bone with areas of flowing and undulating morphology. There was a dense ridge of flowing ossification arising from the roof of the acetabulum that protruded into the hip joint, and narrowing of the superior joint space. CT revealed multiple intra-articular osteocartilaginous loose bodies. MRI of the pelvis and hip (Figure 2) showed the preservation of marrow-fat signal throughout the affected bone. The process demonstrated low signal intensity on T1- and T2-weighted imaging. MRI revealed moderate hip joint effusion with synovitis and multiple intra-articular osteocartilaginous loose bodies. A CT-guided biopsy showed no evidence of malignancy.
What is your diagnosis?
See answer on the next page.
Melorheostosis
The diagnosis of melorheostosis in this case was made by Wegner, who is a musculoskeletal radiologist, based on the characteristic constellation of imaging features on radiographs, CT and MRI. Although the CT showed areas of undulating cortical thickening that had low signal intensity on T1- and T2-weighted MRI that was characteristic of melorheostosis, the process was less characteristic on the radiographs. Consequently, diagnoses such as chronic sclerosing osteomyelitis and bone forming neoplasms were also entertained on the initial radiographic differential diagnosis. The preservation of marrow fat signal intensity on the T1-weighted MR images throughout the affected regions of the bone excluded infection and neoplasm from the differential diagnosis. A CT-guided biopsy was performed to confirm a benign etiology. The pathologic analysis revealed fragments of bone and sclerosis with no evidence of neoplasm or inflammation. The hip joint effusion and loose bodies in the hip joint were thought to be a consequence of the thickened ridge of undulating cortical thickening in the roof of the acetabulum with chronic fragmentation of the ridge of bone and/or secondary osteoarthritis of the hip joint with associated synovitis and loose bodies.
What is your treatment?
The patient’s primary symptoms were consistent with mechanical pain. Therefore, she did not receive bisphosphonate therapy. As she had failed nonoperative management, surgical intervention with hip arthroscopy was recommended predominantly for loose body removal. Limited goals of this surgery were discussed, including the possibility of incomplete pain relief, given the associated arthritic changes involving the acetabulum.
Intraoperatively, the patient was positioned supine on the hip arthroscopy bed. The leg was prepped and draped in the usual fashion and traction was applied. Standard anterolateral and mid-anterior portals were established. Multiple intra-articular loose bodies came into immediate view and were removed (Figure 3). There were multiple loose bodies deep in the fovea, and these were recovered as well. The labrum was intact without tearing, chondrolabral separation or degeneration. The acetabulum had multiple large unstable flaps revealing grade 2 and 3 chondromalacia. There were several large bony spikes in the fovea of the acetabulum that were burred down back to smooth and stable margins. Next, traction was released and there was an excellent labral seal. The capsule was lifted up and multiple additional loose bodies came into view. These were subsequently removed. In the medial synovial fold, there was a 2-cm x 1.5-cm loose body (Figure 4) that was removed with multiple other loose bodies in this location. There were additional loose bodies removed along the lateral side of the femur. In total, 17 intra-articular loose bodies were extracted. The joint was copiously irrigated and the capsule was closed anatomically. Local anesthetic was infiltrated in the deep tissues around the capsule, as well as in the portal sites for postoperative pain control.
Postoperatively, the patient was discharged from the hospital on the day of surgery. She was allowed to progress to weight-bearing as tolerated and was weaned off crutches at 1 week postoperatively. She underwent a comprehensive five-phase hip arthroscopy rehabilitation program. At her clinic visit 2 weeks after surgery, the patient reported 100% resolution of her preoperative hip pain and mechanical symptoms. At 1-year postoperatively, she continued to report complete resolution of all symptoms.
Source: Bruce A. Levy, MD
Discussion
Melorheostosis is a rare disease as its incidence has been reported to be about one in 1 million persons worldwide. Smith and colleagues reported on the largest single institution series of patients with melorheostosis in which patients’ major presenting concerns were pain, limited range of motion and deformity. Pain has been reported as the primary cause of physician referral in multiple series. It is typically monomelic, as was seen in this case report.
Treatment of this condition is symptomatic in nature as no therapeutic measure has been shown to reverse the natural course of the disease. In the series of 24 patients at Mayo Clinic, 11 patients underwent surgery. Surgical procedures performed included patellectomy, total knee arthroplasty, total hip arthroplasty, carpal tunnel release, Z-plasty, contracture release and epiphysiodesis. Arthroscopy has been reported as an effective modality for treatment of knee contracture and removal of intra-articular ossifications. In all cases, symptomatic relief was achieved and range of motion improved. To our knowledge, there are no reported cases of hip arthroscopy used for contracture release or loose body removal in the setting of melorheostosis.
Hip arthroscopy can be effectively performed in a minimally invasive manner. It is used to treat an array of pathologies including labral tears, chondral injuries, instability, femoroacetabular impingement and other conditions. Viktor E. Krebs, MD, has detailed many hip synovial disorders and causes of intra-articular loose bodies, but melorheostosis is not reported as a known indication for hip arthroscopy.
Indications for the use of hip arthroscopy are evolving. We present this patient’s outcomes to showcase a new indication for the use of hip arthroscopy in the symptomatic treatment of a rare condition. By using this minimally invasive technique, we hope additional patients can avoid large open procedures.
For more information:
- A. Noelle Larson, MD; Bruce A. Levy, MD, FAAOS; Heath P. Melugin, MD; Peter S. Rose, MD; and Doris E. Wenger, MD, can be reached in the department of orthopedic surgery, Mayo Clinic, 200 First Street SW, Rochester, MN 55905. Larson’s email: larson.noelle@mayo.edu. Levy’s email: levy.bruce@mayo.edu. Melugin’s email: melugin.heath@mayo.edu. Rose’s email: rose.peter@mayo.edu. Wenger’s email: wenger.doris@mayo.edu.
- Edited by Joshua D. Johnson, MD, and Nicholas A. Trasolini, MD. Johnson is a chief resident in the department of orthopedic surgery at Mayo Clinic in Rochester, Minnesota. He will be a musculoskeletal oncology fellow at MD Anderson following residency. Trasolini is the administrative chief resident in the depart-ment of orthopedic surgery at Keck Medical Center of the University of Southern California and will be a sports medicine fellow at Rush University Medical Center following residency. For information on submitting Orthopedics Today Grand Rounds cases, please email: orthopedics@healio.com.
Disclosures: Levy reports he receives royalties from Arthrex, is a consultant for Arthrex and Smith & Nephew, and is a member of the editorial board of Clinical Orthopaedics and Related Research, Journal of Knee Surgery and Orthopedics Today. Larson, Melugin, Rose and Wenger report no relevant financial disclosures.
- References:
- Claramunt RT, et al. Knee Surg Sports Traumatol Arthrosc. 2011;doi:10.1007/s00167-010-1156-7.
- Freyschmidt J. Eur Radiol. 2001;doi:10.1007/s003300000562.
- Krebs VE. Clin Orthop Relat Res. 2003;doi:10.1097/01.blo.0000043043.84315.5e.
- Smith GC, et al. PM R. 2017;doi:10.1016/j.pmrj.2016.07.530.
- Spencer-Gardner L, et al. Knee Surg Sports Traumatol Arthrosc. 2014;doi:10.1007/s00167-013-2664-z.
- Wynne-Davies R, et al. J Bone Joint Surg Br. 1985;67:133-137.
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