Mucopolysaccharidoses (MPS) And Alpha-mannosidosis: Disease Management – Orthopaedics

Dr. Borgo begins by reviewing the biochemical underpinnings of MPS and alpha-mannosidosis, both lysosomal storage disorders characterized by impaired degradation of complex sugars due to enzyme deficiencies. He categorizes the typical orthopedic features seen in these diseases, including joint stiffness, muscular weakness, skeletal deformities, and growth delays, with an emphasis on early clinical indicators such as painless joint stiffness and reduced elbow pronation.

The presentation discusses the skeletal impact of these conditions across different body regions. In the spine, thoracolumbar kyphosis and cervical instability are common. In the upper limbs, trigger fingers (especially beyond the thumb) and carpal tunnel syndrome in children are flagged as strong indicators of underlying metabolic disease. In the hips, progressive loss of femoral head sphericity, acetabular dysplasia, and eventual joint degeneration are highlighted. The knees and ankles are often affected by valgus deformities and later arthritis, with options for surgical correction depending on timing and severity.

Dr. Borgo stresses that although enzyme replacement therapy (ERT) and hematopoietic stem cell transplantation (HSCT) may slow progression and reduce systemic symptoms, their impact on skeletal deformities remains limited. He presents detailed surgical strategies including osteotomies, physiodesis, and even joint replacement for severe hip and knee degeneration, noting challenges like lack of remodeling capacity in acetabular structures and implant fitting in short-statured patients.

Special attention is given to the differences between MPS and alpha-mannosidosis. While musculoskeletal features overlap, alpha-mannosidosis typically lacks features like short stature and ossification delay. Scoliosis appears more frequently in alpha-mannosidosis, while classic deformities like platyspondyly and flat feet are more commonly observed in MPS.

The webinar concludes with key take-home messages: early orthopedic signs—especially painless joint stiffness, carpal tunnel syndrome, and thoracolumbar kyphosis—should prompt consideration of metabolic disease. Orthopedic surgeons must recognize their pivotal role in early diagnosis and in the multidisciplinary management of MPS and alpha-mannosidosis to optimize patient outcomes.

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