Carpus Overview of the topic Upper Extremity Education taskforce Meeting (Arial 20 pt) 2019 City, Month, Year (Arial 20 pt)

Case: 24 yo fell on outstretched hand after a snowboard jump

Learning objectives Describe how to investigate the problem Classify the lesion Relate injury patterns to indications and treatment Decision making (including avoid complications) Manage using a structured approach

Anatomy and biology Multiple bones, articular surfaces and small ligaments Complex motion – weakest link fails and affects entire joint Poor healing - think scaphoid non union and SL tears that don’t heal with lesser energy injuries Poly trauma patients 25% - compromised healing, other health issues, missed injuries 25%

Mayfield Courtesy of Graham Lister Two names to keep in mind Mayfield and Herzberg Mayfield JK, Johnson RP, Kilcoyne RK. Carpal dislocations: pathomechanics and progressive perilunar instability. J Hand Surg [Am]. May 1980;5(3):226-41 Courtesy of Graham Lister

Mayfield Two names to keep in mind Mayfield and Herzberg Mayfield JK, Johnson RP, Kilcoyne RK. Carpal dislocations: pathomechanics and progressive perilunar instability. J Hand Surg [Am]. May 1980;5(3):226-41

Herzberg Stage I Lunate within fossa Stage IIa Dislocated from fossa but rotated less than 90° Stage IIb Dislocated and rotated 90°+ Herzberg et al2 classified these injuries as stage I when the lunate remains located in its fossa, stage IIA when it is dislocated from it fossa but rotated less than 90°, and stage IIB when it is dislocated and rotated more than 90°

Classification 2/3 have fractures 95% of the fractures are transcaphoid Most are dorsal dislocations 90% Stage IIb can not be closed reduced

Investigation Clinical - median nerve stretch versus compression Radiological plain X-rays 25 % missed CT scan for clarification if required

Key features Radiocarpal joint space Midcarpal joint space Lateral collinearity

Treatment Median nerve Carpus Closed intervention is not enough - failure to heal Re-establish normal relationships Maintain relationships for healing to occur Therapy - early to maintain finger motion Later for wrist motion

Take-home messages Spectrum of injury patterns Check for median nerve dysfunction Thorough x-ray analysis Decompression median nerve where appropriate Surgical intervention to restore and repair normal bone and ligamentous anatomy and allow for slow healing

Surgery Urgent reduction to reduce pressure on median nerve with appropriate monitoring followed by definitive surgical stabilization, see below Urgent ORIF for progressive nerve dysfunction (carpal tunnel release), IIB, open injuries Repair of all bone and soft-tissue to restore carpal stability. ORIF plus ligament repair, maintenance of reduction with IF (K-wires/screws/RASL) Dorsal approach +/- volar approach