Alexander Hamel, BS
Medical Student
University of Massachusetts Chan Medical School
Worcester, Massachusetts, United States
Andrew Duarte, MD
Assistant Professor
University of Massachusetts Chan Medical School
Worcester, Massachusetts, United States
A 46-year-old male with multiple sclerosis (MS) presented with severe chronic right knee pain without injury history. MRI revealed moderate-to-severe distal semimembranosus tendinosis with mild bursitis. He was diagnosed with focal semimembranosus tendinopathy (SMT) and received peri-tendinous ultrasound-guided injection, providing significant pain improvement.
Case Description: The patient presented to his PCP with acute, worsening right knee pain without injury. X-rays were unremarkable. He received physical therapy (PT) knee exercises and botulinum toxin for spasticity. Two years into PT, he reported worsening knee pain and was eventually referred to physiatry after no significant findings of intra-articular nor ligamentous pathology by orthopedics. In the clinic, the patient’s pain was sharp at rest, worse with weight-bearing, and mildly alleviated by ibuprofen and topical diclofenac. MRI revealed a small free edge tear of the lateral meniscus, mild acute-on-chronic MCL sprain, and moderate-to-severe distal SMT with mild semimembranosus bursitis. An ultrasound-guided corticosteroid injection at the tibial insertion of the semimembranosus significantly relieved symptoms.
Discussions:
SMT is an uncommon cause of knee pain in the general population and has not been described in MS. Gait abnormalities and spasticity are common MS complications that can strain tendons and precipitate secondary musculoskeletal conditions. The patient’s gait, compensatory to foot drop, demonstrated excessive knee flexion, overloading the distal semimembranosus tendon. Without well-described SMT treatment recommendations, inferring from other tendinopathy best-practices and the patient’s coexisting bursitis made ultrasound-guided corticosteroid injection the optimal symptom-relieving therapy.
Conclusions: This unusual case demonstrates that altered biomechanics due to MS may overload tendons and cause presentations like other chronic knee pain etiologies. Successful symptom resolution following ultrasound-guided corticosteroid injection in this case supports interventions targeted at the presenting pathology in patients with complex neurological and musculoskeletal conditions. This case broadens the understanding of secondary musculoskeletal complications in MS, underscoring the need for a multidisciplinary management approach in pain management.
