Prader-Willi Syndrome: clinical concerns for the orthopaedic surgeon.

BACKGROUND: Prader-Willi Syndrome (PWS) is a chromosome 15 disorder characterized by hypotonia, hypogonadism, hyperphagia, and obesity. Musculoskeletal manifestations, including scoliosis, hip dysplasia, and lower limb alignment abnormalities, are well described in the orthopaedic literature. However, care of this patient population from the orthopaedic surgeon's perspective is complicated by other clinical manifestations of PWS. Osteopenia, psychiatric disorders, and diminished pain sensitivity are frequently noted in PWS but are not discussed in the orthopaedic literature. The authors present a clinical review of an 8-year experience of caring for 31 patients with PWS to highlight all clinical concerns that influence orthopaedic management.
METHODS: Thirty-one institutionalized patients diagnosed with PWS were examined and all past medical records were reviewed. Patient demographics, genetic testing, musculoskeletal diagnoses, psychiatric diagnoses, and clinical behaviors were recorded. Radiological studies performed in the course of routine clinical care were evaluated.
RESULTS: Twenty-three men and 8 women, with an average age of 22 years (range, 8-39 years), were studied. A chromosome 15q abnormality was confirmed in 18 patients. Scoliosis was clinically detected in 21 of 30 patients and confirmed by radiographs in 14 of these 24 patients (overall with scoliosis, 45%) with an average primary curve of 27 degrees; 3 were braced, and 2 underwent spinal fusion. Radiographs also revealed diminished cervical lordosis and increased cervicothoracic kyphosis in 16 patients, a previously undescribed finding. Hip radiographs of 26 patients revealed dysplasia in 2 patients (13%); no slipped capital femoral epiphysis were identified. Fourteen patients had sustained a total of 58 fractures, with 6 patients sustaining multiple fractures (range, 2-7). Six patients have undergone orthopaedic surgical procedures with one major complication (spinal infection). Fracture management was associated with frequent minor complications. Bone densitometry was performed on 14 patients; 8 patients had osteopenia, and 4 had osteoporosis based on lumbar spine z scores. Twenty-six patients had Axis I psychiatric diagnoses including impulse control disorder (7), organic personality disorder (6), oppositional defiant disorder (5), dysthymic disorder (4), depressive disorder not otherwise specified (3), attention-deficit/hyperactivity disorder (2), and obsessive-compulsive disorder (2). Nine patients exhibited self-mutilating behaviors.
CONCLUSIONS: Osteopenia, poor impulse control and defiant behaviors, and diminished pain sensitivity are aspects of PWS that may complicate all facets of orthopaedic nonsurgical and surgical management in this patient population. The treating orthopaedic surgeon must plan carefully and proceed with caution when treating children and adults with PWS.