Primary Repair Thumb MCPJ UCL Injury - Surgical Technique

The goal of this surgery is to restore strength against valgus force whilst preserving soft tissue structures identified during dissection.
Primary Repair Thumb MCPJ UCL Injury - Surgical Technique

Surgical Checklist

Prepare: Regional or general anaesthesia, tourniquet, and loupes.
Design: ulnar mid-axial side distal to dorsal-ulnar border proximal.
Dissect: Protect dorsal nerve, incise aponeurosis, capsulotomy.
Primary Repair: ligament-ligament, ligament-periosteum.
Close: Layered closure of capsule, aponeurosis & skin.
Post-Op: Elevation, analgesia, immobilization, hand Therapy.

Primary Contributor: Dr Suzanne Thomson, Educational Fellow.
Reviewer: Dr Kurt Lee Chircop, Educational Fellow.


Key Point

To optimise the visualisation of the injured UCL, preparation should include the use of regional or general anesthesia, a tourniquet, and loupes. Surgical adjuncts may also be conside red, depending on the specifics of the case.
  1. Anaesthesia: General or regional anaesthesia. WALANT less common.
  2. Theatre Setup: Arm Table, Tourniquet, Loupes
  3. Tools: Hand Surgery Set, Intra-operative X-Rays, Casting Materials
  4. Considerations: K-Wires, Bone Anchors, Tendon Grasper/Retriever, Internal Brace Suspension Tape


Key Point

Numerous variations of the surgical incision have been described, each designed to provide optimal visualization of both the distal volar insertion and the proximal dorsal-ulnar insertion of the UCL.

  1. Identify the MCPJ with a skin marker.
  2. Define Distal Endpoint: Identify and mark the mid-axial line on the ulnar side of the thumb, just distal to the MCPJ.
  3. Define Proximal Endpoint: Locate and mark the ulnar-dorsal border of the thumb, proximal to the MCP joint.
  4. Connect the Points: Draw a lazy-S from the proximal mark to the distal mark to outline the incision.


Numerous designs have been proposed, including curved and straight-line configurations. All designs should take into consideration that The UCL is most commonly avulsed from it’s insertion on the volar base of the proximal phalanx.


Key Point

Precisely navigate the incision and tissue manipulation to preserve nerve function and maintain tissue viability for successful UCL visualization and potential reconstruction

  1. Incise Skin: Execute the skin incision according to the detailed surgical plan.
  2. Protect dorsal cutaneous nerve, typically just below the skin surface.
  3. Retract the skin and nerve to enhance the surgical field's visibility.
  4. Inspect for Stener Lesion above the adductor aponeurosis.
  5. Incise Adductor Aponeurosis just volar to the EPL tendon ensuring the tissue remains suitable for subsequent repair at closure. It may help to tag this tissue.
  6. Capsulotomy to evaluate the UCL and MCP joint, assessing for osteoarthritis that may affect the feasibility of repair.

Dissection of UCL Injury

Primary Repair of UCL

Key Point

The UCL can undergo primary repair, reinforcement or reconstruction with a tendon graft. Intra-operative findings determine these options.

  1. Mobilize: Free the ligament from surrounding scar tissue to restore its original length.
  2. Bone: small fragments should be exicsed, larger fragments consider fixation.
  3. Ligament-Ligament Repair: Secure the ligament ends directly to each other using non-absorbable sutures for optimal alignment and healing.
  4. Ligament-Periosteal Repair: Suture the ligament to the periosteum, focusing on precise placement for enhanced mechanical stability.


Please note that alternative repair methods like bone anchoring or tendon grafts exist but are not covered here. Avoid primary repair if tissue quality or length is inadequate.


Key Point

Layered closure enhances support for the ligament repair and helps restore the dissected anatomy to its normal configuration.
  1. Re-approximate capsule and adductor aponeurosis
  2. Layered Skin Closure
  3. Administer Local Anesthetic if general anaesthesia was used.
  4. Dressings
  5. Thumb cast application leaving the IPJ free.


Key Point

The post-operative plan should aim to minimize swelling, ensure MCP joint stability, and prevent stiffness. Patients should follow their local hand therapy protocols closely.
  1. Elevate: To reduce swelling and alleviate pain, elevate the limb for the first 24 hours post-operation.
  2. Immobilization: Keep the ligament in a thumb spica cast for 4 weeks, then transition to a lightweight splint for 2 weeks. Avoid forced abduction and radial deviation for 2 months; consult local guidelines.
  3. Hand Therapy: Coordinate with a hand therapist for tailored exercises and movement initiation.
  4. Pain Management: Administer analgesia as needed to manage pain during recovery.

Further Reading/References

  1. Crowley TP, Stevenson S, Taghizadeh R, Addison P, Milner RH. Early active mobilization following UCL repair With Mitek bone anchor. Tech Hand Up Extrem Surg. 2013 Sep;17(3):124-7. doi: 10.1097/BTH.0b013e318284dbd7. PMID: 23970193.
  2. Gluck JS, Balutis EC, Glickel SZ. Thumb ligament injuries. J Hand Surg Am. 2015 Apr;40(4):835-42. doi: 10.1016/j.jhsa.2014.11.009. PMID: 25813924.
  3. Wolfe SW, Pederson WC, Kozin SH, Cohen MS. Green’s operative hand surgery: 8th edition. Elseveir. 2021. ISBN 978032697934. Accessed April 2024
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