Summary Intrinsic Plus Hand is a hand posture characterized by MCP flexion with PIP and DIP extension. caused by imbalance between spastic intrinsics and weak extrinsics muscles of the hand. Diagnosis is made by clinical exam which shows MCP flexion and IP joint extension Treatment may be nonoperative or operative depending on the severity of the contracture and impact on quality of life. Epidemiology Incidence rare < 1 per 100,000 annually Etiology Pathophysiology trauma direct trauma indirect trauma vascular injury compartment syndrome rheumatoid arthritis MCP joint dislocations and ulnar deviation lead to spastic intrinsics neurologic pathology traumatic brain injury cerebral palsy cerebrovascular accident Parkinson's syndrome Pathoanatomy spastic intrinsics leads to flexion of the MCP and extension of the IP joints EDC weakness fails to provide balancing extension force to MCP joint FDS & FDP weakness fail to provide balancing flexion force to PIP and DIP joints Presentation Symptoms difficulty gripping large objects Physical exam inspection MCP joint flexion and IP joint extension provocative tests Bunnell test (intrinsic tightness test) differentiates intrinsic tightness and extrinsic tightness positive test when PIP flexion is less with MCP extension than with MCP flexion Imaging Radiographs no radiographs required in diagnosis or treatment Treatment Nonoperative passive stretching indications mild cases Operative proximal muscle slide indications less severe deformities when there is some remaining function of the intrinsics (e.g., spastic intrinsics) distal instrinsic release (distal to MP) indications more severe deformity involving both MCP and IP joints dysfunctional intrinsic muscles (e.g., fibrotic) Techniques Proximal muscle slide techinque subperiosteal elevation of interossei lengthens muscle-tendon unit Distal intrinsic release technique resection of intrinsic tendon distal to the transverse fibers responsible for MCP joint flexion