Impact of osteoid osteomas of the hip on the size and fatty infiltration of the thigh muscles

Midterm Clinical, Radiological, and Functional Results of Arthroscopic Excision of Osteoid Osteoma of the Hip Joint: a Case Series

Purpose

We aimed to evaluate the midterm functional and clinical outcomes of the patients who underwent arthroscopic excision of hip osteoid osteoma (OO).

Methods

We reviewed records of patients diagnosed with intra-articular hip OO, treated with hip arthroscopic excision procedure, and a minimum of 1-year postoperative between 2011 and 2020. Clinical outcomes were assessed range of motion (ROM) pre and postoperatively, and functional outcomes were evaluated with a modified Harris hip score (modified HHS) and Visual analog scale test. All patients were assessed by hip radiography, and three radiological measurements, including lateral center-edge angle (LCEA), alpha angle, and Tönnis angle, were measured. These parameters were compared with unaffected hips.

Results

Fifteen (5 female and 10 male) patients were included in the study, with a mean age of 32.6 ± 12.7 (range 12-53). The average postoperative follow-up period was 59.1 ± 28 (range 13-106) months. The functional and clinical scores were significantly improved at the final visit compared to the preoperative values. No differences were found between the operated and unaffected sides with respect to the radiological parameters. The preoperative alpha was significantly higher on the operated side than on the unaffected side (p = 0.007).

Conclusion

In this study, within an average of 5 years after surgery, hip arthroscopy provided successful clinical outcomes in the treatment of OO of the hip joint without recurrence. The modified HHS, VAS, and HOS values improved significantly at the final follow-up; 14 of 15 patients had satisfactory outcomes after hip arthroscopy for hip OO.

Level of Evidence

Prognostic Level IV study.

Arthroscopic removal of osteoid osteoma with gamma probe assistance in the hip joint

AIM

The aim was to present the surgical technique and clinical outcome in a series of patients treated with gamma-probe-assisted arthroscopic removal of osteoid osteoma in the hip joint.

METHODS

The case series consisted of 10 patients diagnosed with osteoid osteoma of the hip, who were treated by arthroscopic nidus removal. An endoscopic gamma probe was used intraoperatively to locate the nidus and to control the extent of its removal. Residual osteoma cavities were additionally treated with an arthroscopic radiofrequency ablator. Microfracturing was performed when the osteochondral defect was in the weight-bearing area and osteochondroplasty was done in cases of concomitant cam deformity. Nonarthritic Hip Score (NAHS), Tegner activity score, quality of life questionnaire (EQ-5D) and postoperative magnetic resonance imaging (MRI) were used for evaluation before and post-surgery, with a minimum follow-up of 2 years.

RESULTS

The relative reduction of the gamma irradiation count immediately after removal of the nidus was 44.9% (range 33.3-54.5%). Postoperatively, all patients experienced prompt pain relief and a significant improvement according to all patient reported outcomes. Control MRI revealed fibro-cartilaginous tissue repair of post-osteoma osteochondral defects in the weight-bearing area; 1 patient showed signs of early degeneration.

CONCLUSIONS

The results of this case series demonstrated the safety and high efficacy of gamma-probe-assisted arthroscopic removal of the osteoid osteoma from the hip joint. Endoscopic gamma probe was recognised as a very useful device for locating the nidus of the osteoid osteoma exactly and preventing incomplete or excessive removal of the bone.

Subtrochanteric osteoid osteoma: A misdiagnosed case complicated by a hip fracture

A 34-year-old man with a subtrochanteric osteoid osteoma localized to the lateral cortex of the left femur is reported. The patient presented with mild spontaneous pain of the lateral thigh and knee. He refused a radiographic examination and was treated as a greater trochanteric pain syndrome for 9 months. He was then admitted with a transcervical fracture of the neck of the left femur after a fall from standing height. The fracture was fixed with 3 cannulated screws and healed uneventfully. His symptoms worsened after the first postoperative year. Eighteen months postoperatively the pain was dull, worsening at night, and relieved only with anti-inflammatory drugs, and he had a limp. New radiographs and tomograms were indicative of a lateral subtrochanteric osteoid osteoma with a subperiosteal localization. The lesion was treated successfully with surgical excision of a piece of reactive bone including the nidus.

An increased iliocapsularis-to-rectus-femoris ratio is suggestive for instability in borderline hips

BACKGROUND

The iliocapsularis muscle is an anterior hip structure that appears to function as a stabilizer in normal hips. Previous studies have shown that the iliocapsularis is hypertrophied in developmental dysplasia of the hip (DDH). An easy MR-based measurement of the ratio of the size of the iliocapsularis to that of adjacent anatomical structures such as the rectus femoris muscle might be helpful in everyday clinical use.

QUESTIONS/PURPOSES

We asked (1) whether the iliocapsularis-to-rectus-femoris ratio for cross-sectional area, thickness, width, and circumference is increased in DDH when compared with hips with acetabular overcoverage or normal hips; and (2) what is the diagnostic performance of these ratios to distinguish dysplastic from pincer hips?

METHODS

We retrospectively compared the anatomy of the iliocapsularis muscle between two study groups with symptomatic hips with different acetabular coverage and a control group with asymptomatic hips. The study groups were selected from a series of patients seen at the outpatient clinic for DDH or femoroacetabular impingement. The allocation to a study group was based on conventional radiographs: the dysplasia group was defined by a lateral center-edge (LCE) angle of < 25° with a minimal acetabular index of 14° and consisted of 45 patients (45 hips); the pincer group was defined by an LCE angle exceeding 39° and consisted of 37 patients (40 hips). The control group consisted of 30 asymptomatic hips (26 patients) with MRIs performed for nonorthopaedic reasons. The anatomy of the iliocapsularis and rectus femoris muscle was evaluated using MR arthrography of the hip and the following parameters: cross-sectional area, thickness, width, and circumference. The iliocapsularis-to-rectus-femoris ratio of these four anatomical parameters was then compared between the two study groups and the control group. The diagnostic performance of these ratios to distinguish dysplasia from protrusio was evaluated by calculating receiver operating characteristic (ROC) curves and the positive predictive value (PPV) for a ratio > 1. Presence and absence of DDH (ground truth) were determined on plain radiographs using the previously mentioned radiographic parameters. Evaluation of radiographs and MRIs was performed in a blinded fashion. The PPV was chosen because it indicates how likely a hip is dysplastic if the iliocapsularis-to-rectus-femoris ratio was > 1.

RESULTS

The iliocapsularis-to-rectus-femoris ratio for cross-sectional area, thickness, width, and circumference was increased in hips with radiographic evidence of DDH (ratios ranging from 1.31 to 1.35) compared with pincer (ratios ranging from 0.71 to 0.90; p < 0.001) and compared with the control group, the ratio of cross-sectional area, thickness, width, and circumference was increased (ratios ranging from 1.10 to 1.15; p ranging from 0.002 to 0.039). The area under the ROC curve ranged from 0.781 to 0.852. For a one-to-one iliocapsularis-to-rectus-femoris ratio, the PPV was 89% (95% confidence interval [CI], 73%-96%) for cross-sectional area, 77% (95% CI, 61%-88%) for thickness, 83% (95% CI, 67%-92%) for width, and 82% (95% CI, 67%-91%) for circumference.

CONCLUSIONS

The iliocapsularis-to-rectus-femoris ratio seems to be a valuable secondary sign of DDH. This parameter can be used as an adjunct for clinical decision-making in hips with borderline hip dysplasia and a concomitant cam-type deformity to identify the predominant pathology. Future studies will need to prove this finding can help clinicians determine whether the borderline dysplasia accounts for the hip symptoms with which the patient presents.

LEVEL OF EVIDENCE

Level III, prognostic study.