MALLET FINGER
April 30, 2014
UCL INJURY- THUMB
April 30, 2014

STENER LESION

Description:
The ulnar collateral ligament provides stability to the metacarpal-phalangeal (MCP) joint of the thumb in flexion and valgus.  It originates from the ulnar distal aspect of the first metacarpal and attaches onto the proximal ulnar portion of the proximal phalanx.   Injuries to the Ulnar Collateral (UCL) Ligament can involve a sprain, tear and avulsion.    The UCL ligament is lax in extension and taught in flexion.  Tear can lead to pain with pinching grip. (1)  A complete rupture of the ulnar collateral ligament results in a stener lesion in 80% of cases. (2)  A stener lesion results in torn proximal ligament of UCL getting caught superficially over the aponeurosis of adductor pollicis (See Figure 2).  The separation of the proximal and distal ligament segments by the adductor aponeurosis prevents healing.
Figure 1 – Rupture of Ulnar Collateral Ligament of ThumbUCLtear 1

Figure 2 – Stener Lesion – UCL proximal portion in blue, Add- Adductor Pollicis Aponeurosis, MC – Metacarpal, PP – Proximal Phalanx, DP – Distal Phalanx
Stenerlesion

 

Exam:  

Inspection – May notice swelling at the ulnar side of the MCP joint

Palpation – The ulnar side of the 1st MCP joint will be tender

AROM – May be restricted due to effusion in joint but should be able to extend and flex against resistance.

PROM – Pain and apprehension may be present with flexion and extension of 1st MCP as well as possible restriction due to effusion.

Special Tests – Valgus stressing of D1 MTP joint in 30 degrees of flexion (3,4)(see image) may reveal increased gapping of joint compared to opposite side as well as pain.  However due to pain in joint, gapping may not be present acutely. (5).  Neurovascular examination should be normal.

Investigations:

Xray – of D1 (thumb) – assess for fracture, avulsion of Ulnar collateral ligament.

US – of D1 (thumb) – assess for Stener Lesion.

MRI – If US inconclusive or not matching clinical impressions, MRI can provide a more definitive visualization of the UCL, adductor aponeurosis and evidence of boney edema from injury.

Management:

Conservative Treatment:
Partial injuries and non displaced avulsion fractures – immobilization in cast, splint or brace to block thumb abduction for at least 4-6 weeks(1-3,7). Criteria for return to sport is no pain, firm end point with radial deviation stress and recovery of at least 80% range-of-motion (ROM) and pinch strength. Rehab should be started at 3-4 weeks after injury and include thumb MCP.   ROM exercises and strengthening of forearm flexors, extensors and intrinsic muscles of the hand. Should be protected for 2-3 months with removable splint for activity.

Surgical Intervention:
Referral is required for complete tears (1-3,6)(>35 degrees opening on valgus stress), displaced avulsion fractures > 2 mm, intraarticular fracture > 20% of articular surface, concern for stener lesion or symptomatic chronic injury.(7)

Dr. Neil Dilworth  and Dr. Wes Clayden  ( April 30, 2014 – PR WC)

References: 

(1) Brukner P. Clinical sports medicine. Rev. 3rd ed. ed. Toronto: McGraw-Hill; 2009.

(2) Review of orthopaedics. 5th ed. ed. Philadelphia: Saunders / Elsevier; 2008.

(3) Eiff MP. Fracture management for primary care. 2nd ed. ed. Philadelphia: Saunders; 2003.

(4) Leversedge FJ. A pocketbook of hand and upper extremity anatomy: primus manus. 1st ed. ed. Philadelphia: Lippincott Williams & Wilkins; 2010.

(5) Chan K, Micheli L, Smith A, Rolf C, Bachl N, Frontera W, et al. F.I.M.S. Team Physician Manual. ; 2006. p. 14-15-32.

(6) Hand surgery. Philadelphia: Lippincott Williams & Wilkins; 2004.

(7)  Eiff MP. Fracture management for primary care. 2nd ed. ed. Philadelphia: Saunders; 2003.

(8) DeLee & Drez’s orthopaedic sports medicine : principles and practice. 2nd ed. ed. Philadelphia: Saunders; 2003.