summary Camptodactyly is a rare congenital condition of the hand that is characterized by a digital flexion deformity that usually occurs in the PIP joint of the small finger. Diagnosis is made clinically. Treatment is usually observation with passive stretching in the majority of cases. Surgical management is indicated in cases of progressive deformity leading to functional impairment. Epidemiology Prevalence less than 1% Anatomic location unilateral (33%) or bilateral (66%) if bilateral, can be symmetric or asymmetric Etiology Pathophysiology typically caused by either abnormal lumbrical insertion/origin abnormal (adherent, hypoplastic) FDS insertion other less common causes include abnormal central slip abnormal extensor hood abnormal volar plate skin, subcutaneous tissue, or dermis contracture Genetics most often sporadic can be inherited with autosomal dominant inheritance with incomplete penetrance/variable expressivity Associated conditons can be associated with more widespread developmental dysmorphology syndromes Classification Benson Classification Type Characteristics Treatment Type I Isolated anomaly of little finger, presents in infancy and affects males and females equally Most common form Stretching/splinting Type II Same clinical features as Type I, presents in adolescence Affects girls more often than boys. Form abnormal lumbrical insertion, abnormal FDS origin or insertion If full PIP extension can be achieved actively with MCP held in flexion, digit can be explored and abnormalFDS tendon transferred to radial lateral band Type III Severe contractures, multiple digits involved, presents at birth Usually associated with a syndrome Non-operative (unless functional deficit exists after skeletal maturity), then consider corrective osteotomy/fusion Kirner's Deformity Specific deformity of small finger distal phalanx with volar-radial curvature (apex dorsal-ulnar) Often affects preadolescent girls Often bilateral Usually no functional deficits Presentation Symptoms often goes unnoticed as usually only affects small finger and is very rarely associated with any significant compromise in function typically painless and without motor/sensory deficits Physical exam flexion deformity of small finger PIP joint flexible (correctable) or fixed (non-correctable) deformity progressively worsens over time if untreated may rapidly worsen during growth spurts normal strength, sensation, perfusion usually normal DIP and MCP joint alignment, however compensatory contractures can develop no swelling, erythema, or warmth; not associated with inflammation Imaging Radiographs often normal, especially in early stages later stages: possible decrease in P1 head convexity; possible volar subluxation and flattening of base of P2 Treatment Nonoperative passive stretching, splinting indications nonoperative treatment is favored in most cases best for PIP contracture < 30 degrees technique passive stretching + static splinting outcomes variable outcomes best outcomes with early intervention Operative FDS tenotomy +/- FDS transfer indications progressive deformity leading to functional impairment technique must address all abnormal anatomy passive (correctable) deformities FDS tenotomy, or FDS transfer to radial lateral band if full active PIP extension can be achieved with MCP flexion osteotomy vs. arthrodesis indications severe fixed deformities outcomes variable outcomes