Double Trouble No More: A Case Report of En-bloc Resection and Total Hip Replacement for Secondary Hip Osteoarthritis Due to Femur Neck Osteochondroma

Abstract

Introduction: Osteochondroma is a long bone benign tumor presenting at the metaphysis. Most of the occurrences are isolated lesions with very rare intra-articular extensions. Some occur as part of multiple hereditary exostoses. Isolated lesions are typically asymptomatic and diagnosed incidentally but, in some cases, present with bursa inflammation, pain, decreased range of motion and neurovascular deficit due to the mass effect of the tumor. Osteochondroma of the femur neck presents as an intra-articular pathology.

Case report: A 41-year-old lady presented with right inguinal pain and swelling for 7 years, with an associated decreased range of movements of the right hip. Clinical examination revealed gross bony hard swelling, non-tender, and no local warmth. ROM was restricted, particularly internal rotation with additional abduction contracture and anterior joint line tenderness. A plain radiograph revealed a bony mass over metaphyseal-diaphyseal swelling over the medial aspect of the proximal femur with loss of femur head morphology and joint space narrowing. MRI confirmed the lesion as osteochondroma and a provisional diagnosis of Sessile solitary osteochondroma with probable sarcomatous with secondary degenerative osteoarthritis of the right hip was made. The patient underwent right total hip replacement with wide excision of the entire proximal femur using a REEF stem. The samples sent for histopathology confirmed the diagnosis as osteochondroma with no sarcomatous changes. Over a 10-year period of follow up, the patient showed no evidence of recurrence with improvement of hip movements assessed by Modified Harris Hip Score.

Conclusion: By planning and executing total hip replacement with REEF stem and wide excision of the tumor in a single sitting, both the progress of the tumor and the secondary degenerative arthritis were met with, in a single procedure.

Keywords: Osteochondroma; chondrosarcoma; osteoarthritis; total hip replacement.

Figure 1

(a) Pre-operative X-ray proximal femur – AP view, (b) Pre-operative X-ray pelvis with both hips – AP view.

Figure 2

Intraoperative photo – Excision of the tumor.

Figure 3

REEF stem insertion.

Figure 4

Immediate Post-operative X-ray.

Figure 5

Follow-up X-rays. (a) 4-year-old follow-up AP and Lat views, (b) 8-year-old follow-up AP and Lat views, (c) 10-year-old follow-up AP and Lat views.