Thumb Ligament Injuries

Original Editor - Habibu Salisu Badamasi
Top Contributors - Habibu Salisu Badamasi and Kim Jackson

Introduction

Thumb ligament injuries are common, particularly those involving the metacarpophalangeal joint.Two major ligaments stabilize the MCP joint of the thumb: the ulnar collateral ligament (UCL) and the radial collateral ligament (RCL)[1]

Clinical Relevant Anatomy

The thumb MCP is similar in anatomical appearance to those of the finger,but essentially functions as a hinge or ginglymus joints. The articular morphology found in this joint makes it the most varied motion of all joints, with range of motion of 6 to 86 degree in flexion-extension. [2]

  • flexor pollicis brevis (FBP)
  • Abductor pollicis brevis (APB) muscles insert partially on the sesamoids and provide stability against hyperextension forces.
Hand and wrist bones II.JPG

The ligamentous anatomy is analogous to that seen in the finger MCP joints, with extrinsic tendons providing additional support


Mechanism of Injury / Pathological Process

The Metacarpophalangeal (MCP) joint of the thumb are stabilize by two major ligaments. The ulnar collateral ligament (UCL) and the Radial collateral ligament (RCL) . The UCL is more commonly injured, usually from forced radial deviation (abduction) of the thumb, while the RCL are rarely injuried. However, in severe type of injuries, both ligaments may be ruptured.[1]

Clinical Presentation

Thumb ligament injuries usually occur from a forced radial deviation (abduction) of the thumb during a high-velocity activity. Skiers and those who play ball-handling sports, such as baseball, football and basketball, have a greater risk of sustaining such an injury.

  • Skiers can injure the thumb ligament in accidents involving the ski poles or from a fall.
  • Ball-handling players often sustain thumb injuries when the ball forcefully abducts the digit, resulting in a UCL tear.
  • Stener lesions: when the thumb is hyper extended by the ball, the RCL may be torn instead.(Capsular injuries or stener lesions A Stener lesion is a radiographic finding indicating a complete rupture of the UCL with the adductor aponeurosis interposed between the distally avulsed ligament and its insertion into the base of the proximal phalanx.

Diagnostic Procedures

History taking, including mechanism, finger position during injury, the presence of deformity, previous treatment received and subjective sense of stability of the injured thumb.

• Neurovascular exam must determine motor function, perfusion, and sensation.

• Weakness with pinch function usually exists in ligament ruptures.

• Examine the base of the thumb for ligamentous laxity and compare it to the uninjured hand:

• Examine the thumb with 20–30* of flexion.

• Carefully abduct the thumb passively and compare the angle of deviation to the uninjured thumb.

• An angulation of >30* on the injured thumb or >15* compared to the uninjured thumb is diagnostic for a ligamentous injury.

• Radiography should be obtained to assess for the presence of a Stener's lesion or a fracture fragment.

•further assessment of joint should be performed using a digital block may be necessary to complete a full examination

because of pain and swelling in the acute setting


Outcome Measures

add links to outcome measures here (see Outcome Measures Database)

Management / Interventions

A thumb spica splint or cast immobilization is indicated for 4 weeks for a partial rupture, or up to 6 weeks if an associated avulsion fracture is present.

For acute injury

• Rest, elevation, ice

• Immobilization in a thumb spica splint

• Analgesics

• Orthopedic follow-up

For chronic injury

• Thumb spica brace

• Activity modifi cation

• Orthopedic surgery consultation for elective ligament repair or reconstruction may be necessary with a complete rupture. Physical or occupational therapy is helpful postoperative to increase range of motion and strength, and to assist in resuming activities

Differential Diagnosis

• First metacarpal or proximal phalanx fractures

• First CMC joint arthritis

• Volar plate injury

Resources

add appropriate resources here

References

  1. 1.0 1.1 Weiss L, Weiss J, Pobre T. Oxford American handbook of physical medicine & rehabilitation. Oxford University Press, USA; 2010 Mar 15.
  2. Skirven TM, Osterman AL, Fedorczyk J, Amadio PC, Felder S, Shin EK. Rehabilitation of the hand and upper extremity. Elsevier Health Sciences; 2020 Jan 14.