Thumb Radial Collateral Ligament Injury

• ICD-9 = 842.12 (Sprains and strains of metacarpophalangeal joint of hand)
• 1/10 as common as UCL injury
• caused by extension and adduction injuries

Thumb RCL Clinical Evaluation

tenderness at ligament origin and insertion
pain exacerbated by torsional motions such as turning doorknobs or with axial compression such as pushing in buttons on car doors.
30 degrees increased laxity in extension and 30 degrees flexion to ulnar deviation as compared to uninjured side =  complete rupture. 
Partial injuries will have firm end-point

Thumb RCL Xray

• PA, lateral and oblique views.  Generally normal; occasionally proximal phalanx may be deviated ulnarly; may have avulsion fragment.  Palmar subluxation is common

Thumb RCL Classification / Treatment

• Partial tear (have firm end point on exam) = thumb spica cast 4-6 wks
• Complete tears =  operative repair

Thumb RCL Technique

• “lazy S” incision
• dorsal branch of radial sensory nerve gently retracted
• abductor aponeurosis incised longitudinally exposing ligament and joint
• inspect for intraarticular patholoty
• tear isoloated
• mibsubstance tear=repair with 4-0 ethibond, incorporate part of palmar plate with deepest suture
• bony avulsions repaired with pull-out suture(monofilament passed with Keith needles) over button, or Mitek mini-anchors; +/- k-wire fixation of joint
• close abductor aponeurosis with 4-0 pds, skin 5-0 chromic

Thumb RCL Follow-up

• thumb-spica cast for 4-6 wks
• customized thermoplastic “thumb cone” splint.  ROM exercises
• two weeks after cast start full AROM
• 3 wks out of cast start strengthening, wean out of splint.

Thumb RCL Complications