A 65-yr-old male presented to acute rehabilitation following C3–C7 posterior decompressive laminectomy due to severe cervical stenosis. He had previously undergone craniotomy for Arnold–Chiari malformation in 1977 and had a long history of syringomyelia. Since the initial finding of Arnold–Chiari malformation, the patient has had residual right-side weakness and numbness. On physical examination, distal phalangeal contractures and thenar intrinsic atrophy were noted bilaterally. Old burn scars were apparent on the right forearm. Active abduction in the right shoulder was limited to 80 degrees. Cranial nerves II through XII were intact. Sensation at C4–T1 on the left was diminished and virtually absent over the right upper extremity. Proprioception was diminished in the right upper and lower extremities. Decreased deep tendon reflexes were noted throughout. Manual muscle testing revealed 4/5 strength in both upper extremities with the exception of hand intrinsics, which were 2/5 bilaterally, with the right finger flexors being 3/5. The left lower-extremity muscles were of normal strength. The right lower-extremity hip flexors were 4/5; the knee extensors, dorsiflexors, long-toe extensors, and ankle plantar flexors were 2/5 in muscle strength.
A few days after admission, the patient was noted to have worsening rhonchi and sputum production. Radiographs of the chest revealed a perihilar infiltrate. In addition, destructive changes in the right shoulder joint and resorption of the humeral head (findings consistent with a neuropathic arthroplasty) were noted.
Neuropathic arthropathy (Charcot joint) is a destructive joint disease frequently associated with syringomyelia (Fig. 1). It is thought to be caused by loss of sensation and proprioception and/or unnoticed recurrent trauma.1 In this case, neuropathic arthropathy of the shoulder was a result of the syringomyelia, which may sometimes be a complication of Arnold–Chiari malformation.2,3 The patient was able to recall repeated trauma to the right shoulder and arm but was relatively asymptomatic because of the areas that were insensate. Joints most commonly involved in the patients with syringomyelia are the shoulder and elbow, whereas in diabetics, the ankle and foot predominate.4 Other causes of neuropathic arthropathy include alcoholism, frequent intra-articular corticosteroid injections, syphilis, and Charcot–Marie–Tooth disease.
Painful neuropathic joints develop in 25% of patients with syringomyelia.3 In this vignette, the patient had a painless right shoulder, which is usually a late feature. Other findings in neuropathic arthropathy include swelling and loss of motion. Neuropathic arthropathy should be considered in unexplained shoulder instability and pain and is easily depicted on standard x-rays.1
Treatment is usually conservative. NSAIDs may reduce inflammation or swelling. Establishing ways to prevent further joint trauma through the concept of joint protection is key. Continued passive stretching exercises to optimize range of motion of the affected joint should be considered; however, immobilization with hopes of preventing further injury has also been suggested.2 Surgical intervention is rarely indicated.
1. Yanik B, Tuncer S, Seckin B: Neuropathic arthropathy caused by Arnold-Chiari malformation with syringomyelia. Rheumatol Int
2. Jones J, Wolf S: Neuropathic shoulder arthropathy (Charcot Joint) associated with syringomyelia. Neurology
3. Riente L, Frigelli S, Delle Sedie A, et al.: Neuropathic shoulder associated with syringomyelia and Arnold-Chiari malformation (Type I). J Rheumatol
4. Hazis N, Kaar TK, Wirth MA, et al.: Neuropathic arthropathy of the shoulder. J Bone Joint Surg