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SPRAIN, THUMB MP JOINT (RADIAL COLLATERAL LIGAMENT)

Introduction

Injuries to the collateral ligaments of the thumb metacarpophalangeal (MP) joint, which range from mild sprains to complete ruptures, are among the most common injuries of the hand. The majority of these injuries involve the ulnar collateral ligament (UCL), while radial collateral ligament (RCL) injuries occur far less frequently. The typical mechanism of injury is hyperextension with hyperabduction or hyperadduction to the joint, and incidence rates are therefore high in ball-handling sports and skiing. Conservative treatment is usually sufficient for minor ligamentous injuries, while surgery is often required for complete ruptures and patients with extremely unstable thumb MP joints, although both approaches have been associated with positive outcomes.1-3  Chronic untreated complete RCL injuries may become increasingly symptomatic over time.  These patients, pain and instability can be helped by repair or reconstruction of the RCL.  If there is arthritis in the thumb MP joint then arthrodesis rather than repair of the RCL will be needed.
 

Pathophysiology

  • Ligamentous injuries of the thumb MP joint typically result from a force that causes hyperextension and either hyperabduction or hyperadduction of the joint. Hyperadduction of the thumb MP joint leads to damage of the RCL1,2
  • RCL injuries occur far less frequently than UCL injuries—accounting for 10-40% of thumb MP joint collateral ligament injuries4 —and simultaneous tears of the RCL and UCL have also been described.  RCL injuries commonly occur from sports-related trauma, mostly in ball-handling sports, or from a fall on an outstretched hand (FOOSH).3
  • The evaluation, diagnosis, and management of RCL injuries is similar to UCL injuries, but there are several key differences between the two:
    1. The equivalent of a Stener lesion on the radial side is extremely rare to nonexistent because the abductor aponeurosis is broad and does not become interposed between the ligament ends.
    2. The location of RCL injuries is more variable than UCL injuries, with 55% of cases being proximal, 29% distal, and 16% midsubstance.5

Related Anatomy6,7

  • UCL: proper and accessory
  • RCL: proper and accessory
  • Dorsal capsule
  • Volar plate
  • The thumb MP joint is a diarthrodial hinge joint that has a variably flattened metacarpal head compared with its digital counterparts. Its main range of motion (ROM) is in flexion and extension with a lesser amount of abduction, adduction, and rotation.1
  • The volar plate—with its embedded 2 sesamoid bones—along with the RCL and UCL provide static stabilization to the thumb MP joint. The principal dynamic stabilizer is the adductor pollicis, which resists valgus forces, while the intrinsic and extrinsic musculature offers additional dynamic stability.1
  • The distal width of the RCL insertion is wider than the width of the proximal metacarpal neck origin, which may be one reason proximal tears occur more frequently than distal tears with RCL injuries, while most UCL tears occur in the proximal phalanx.8
  • Ligamentous injuries of the thumb MP joint are typically classified using the following system:
    • Grade 1: involves asymmetric swelling and tenderness over the collateral ligament without instability on the lateral stress test
    • Grade 2: involves significant disruption of the collateral ligament, but the volar plate remains intact. There is some instability, but stress testing both in extension and flexion reveals a definite soft tissue endpoint indicating that the collateral is not completely torn.
    • Grade 3: involves total collateral ligament disruption and volar plate rupture, with clinical examination depicting evidence of subluxation or dislocation on active extension.9,10 Stress testing reveals no soft tissue endpoint indicating that the collateral is completely torn.

Incidence and Related Conditions

  • One study found that finger injuries accounted for 38% of 3.5 million upper extremity injuries in the U.S. About 16% of these injuries were sprains and strains, while dislocations only accounted for ~5%.11
  • The incidence of finger sprains is 37.3 per 100,000 person/years, and the proximal interphalangeal (PIP) joint is the most commonly injured joint of the hand, followed by the thumb MP joint and MP joint of the fingers. Due to their infrequency, statistics are lacking on the specific occurrence rates of sprains to the distal interphalangeal (DIP) joint of the fingers and thumb interphalangeal (IP) joint.11
  • Injuries involving the ligaments of the thumb MP joint account for ~86% of all thumb injuries.12
  • The collateral ligaments of the MP joints are damaged in approximately 1 out of every 1,000 hand injuries. Of these, 61% involve the thumb MP joint and 39% involve the MP joints of the fingers.13

Differential Diagnosis

  • Collateral ligament tear
  • Volar plate tear
  • Thumb MP joint dislocation
  • Trigger thumb
  • Thumb proximal phalanx fracture
  • Thumb metacarpal fracture
  • Thumb CMC joint sprain or dislocation
  • Thumb MP joint sprain or dislocation
  •  
ICD-10 Codes

  • SPRAIN

    Diagnostic Guide Name

    SPRAIN

    ICD 10 Diagnosis, Single Code, Left Code, Right Code and Bilateral Code

    DIAGNOSISSINGLE CODE ONLYLEFTRIGHTBILATERAL (If Available)
    - WRIST    
     - CARPAL JOINT S63.512_S63.511_ 
     - RADIOCARPAL JOINT S63.522_S63.521_ 
     - OTHER SPECIFIED SPRAIN OF WRIST S63.592_S63.591_ 
    - METACARPOPHALANGEAL (MCP)    
     - INDEX S63.651_S63.650_ 
     - MIDDLE S63.653_S63.652_ 
     - RING S63.655_S63.654_ 
     - LITTLE S63.657_S63.656_ 
     - THUMB S63.642_S63.641_ 
    - INTERPHALANGEAL (DIP, PIP)    
     - INDEX S63.631_S63.630_ 
     - MIDDLE S63.633_S63.632_ 
     - RING S63.635_S63.634_ 
     - LITTLE S63.637_S63.636_ 
    - CARPOMETACARPAL OF THUMB (CMC) S63.8X2_S63.8X1_ 

    Instructions (ICD 10 CM 2020, U.S. Version)

    THE APPROPRIATE SEVENTH CHARACTER IS TO BE ADDED TO EACH CODE FROM CATEGORY S63
    A - Initial Encounter
    D - Subsequent Routine Healing
    S - Sequela

    ICD-10 Reference

    Reproduced from the International statistical classification of diseases and related health problems, 10th revision, Fifth edition, 2016. Geneva, World Health Organization, 2016 https://apps.who.int/iris/handle/10665/246208

Clinical Presentation Photos and Related Diagrams
Thumb Radial Collateral Ligament Injury
  • A 27 year old male who injuried this right thumb two months ago in a basketball game. He did not seek treatment but now complaining of right thumb instability and pain. Stress test of the radial collateral ligament shown.
    A 27 year old male who injuried this right thumb two months ago in a basketball game. He did not seek treatment but now complaining of right thumb instability and pain. Stress test of the radial collateral ligament shown.
  • Different view of the radial collateral ligament stress test.
    Different view of the radial collateral ligament stress test.
Symptoms
History of thumb trauma with thumb MP joint instability and/or deformity
Pain, swelling, tenderness, and ecchymosis over radial aspect of the thumb MP joint
Decreased thumb motion and impaired grip/pinch strength
Typical History

The typical patient is a 28-year-old, right-handed male who was cycling at a fast speed when he crashed. He landed on his left thumb.  This caused a hyperadduction injury to the left thumb MP joint.  The trauma resulted in a tear of the RCL in his left thumb.  The cycler subsequently experienced severe pain surrounding the thumb MP joint. Later, he noticed swelling, tenderness, and ecchymosis around the joint.  The increasing pain prevented him from riding for the remainder of the day.  In the emergency room, the exam was consistent with a complete rupture of the RCL. The patient was treated non-operative with a splint and later with a thumb spica cast.  His grade three non-displaced RCL injury was immobilized for six weeks.

Positive Tests, Exams or Signs
Work-up Options
Images (X-Ray, MRI, etc.)
RCL X-ray
  • Radial collateral ligament stress X-ray. Note normal lateral view (insert).
    Radial collateral ligament stress X-ray. Note normal lateral view (insert).
Treatment Options
Treatment Goals
  • The goal of treatment for ligamentous injuries of the thumb MP joint is to obtain a strong, stable, and pain-free joint with an optimum range of motion.17
Conservative
  • The standard of care for thumb MP joint sprains and ligament ruptures is somewhat variable, but in general, nearly all grade 1 and most grade 2 injuries are treated conservatively with a period of immobilization. Some grade 2 injuries that are extremely unstable and the grade 3 injuries may require surgery or casting. Casting alone maybe particularly efficacious when the complete ligament ruptures that are minimally displaced.1,2
  • Immobilization options include short-arm thumb spica casting, hand-based thumb spica casting, custom hand-based thermoplast splints, removable thumb spica splints, and functional hinged splints. Whatever approach is used, the most important aspect is to protect the thumb MP joint from stress while allowing the thumb IP joint to move freely to avoid stiffness.1
  • The length of immobilization needed ranges from 10 days to 6 weeks depending on the extent of injury.1
    • Some authors recommend immobilization for 2 weeks for mild grade 1 sprains, while grade 2 sprains may show mild ligamentous laxity and require 2-4 weeks before progressing to exercise. The resolution of RCL ligament tenderness is a useful guide for assessing ligament healing.  Chronic ligament injuries are more difficult to manage and their outcome is less predictable.2
    • At 4 weeks, occupational or physical therapy to regain range of motion can begin, with a particular focus in the flexion/extension plane while avoiding valgus stresses at the MP joint. At this time, immobilization is only required in high-risk activities. Strengthening begins at 6-8 weeks, with unrestricted activity usually permitted at 12 weeks.1
  • In appropriate patients nonsteroidal anti-inflammatory drugs should can be used cautiously and for short period of time.9
  • Steroid injections may reduce pain and inflammation but can be detrimental to healing. Many experts therefore caution against their use for acute thumb MP joint sprains.9
Operative
  • Surgery is usually indicated for grade 2 injuries with marked instability and most grade 3 injuries, unless the rupture is minimally displaced, in which case conservative treatment may be sufficient. Complete rupture of the RCL is defined as >30° of valgus deviation, 15° more laxity compared with the contralateral side, or lack of a firm endpoint.1,5
  • Acute, complete ruptures <3 weeks old are may be treated with ligament repair, which requires that the native tissue is of adequate length and quality. If the tissue is lacking in either characteristic, reconstruction should be undertaken.  Surgeons may also immobilize the thumb MP joint with a K-wire for 4 weeks to protect it from stress during healing.1
  • Reconstruction is rarely needed for RCL ruptures, even in cases of delayed diagnosis. Anatomic repair of the RCL affords greater joint stability because it neutralizes the ulnar pull of the adductor pollicis and extensor pollicis longus (EPL).5
  • After surgery, the thumb MP joint should be immobilized in a forearm-based thumb spica splint and the IP joint is left free to prevent adhesions of the EPL tendon. The splint is removed at postoperative day 3-5 and is replaced by a removable thermoplastic splint or cast, which is discontinued at week 4 for general activities and continued  range of motion exercises with strengthening exercises starting at 6 weeks. Full return to activities is permitted at 3 months.1
Treatment Photos and Diagrams
Surgical Repair of Radial Collateral Ligament Injur
  • Dorsal radial approach to the right thumb MP joint torn radial collateral ligament. Torn RCL (1) with probe in MP joint; EPB tendon (2); Abductor aponeurosis (3).
    Dorsal radial approach to the right thumb MP joint torn radial collateral ligament. Torn RCL (1) with probe in MP joint; EPB tendon (2); Abductor aponeurosis (3).
  • Right thumb MP joint with torn radial collateral ligament. Edge of EPB (1) ; Dorsal MP joint capsule (2); Insertion site of torn RCL (3); Radial collateral ligament (4).
    Right thumb MP joint with torn radial collateral ligament. Edge of EPB (1) ; Dorsal MP joint capsule (2); Insertion site of torn RCL (3); Radial collateral ligament (4).
  • Right thumb MP joint showing dorsal MP joint capsule (1); radial collateral ligament with pullout blue suture and repair suture in place (2 ); Hole in metacarpal head (3) for passing pullout suture which exits dorsal ulnarly (4).
    Right thumb MP joint showing dorsal MP joint capsule (1); radial collateral ligament with pullout blue suture and repair suture in place (2 ); Hole in metacarpal head (3) for passing pullout suture which exits dorsal ulnarly (4).
  • Right thumb MP joint torn radial collateral ligament and capsule repaired (1); EPB tendon edge and abductor aponeurosis (2) before repair and after in insert.
    Right thumb MP joint torn radial collateral ligament and capsule repaired (1); EPB tendon edge and abductor aponeurosis (2) before repair and after in insert.
  • Right thumb MP joint after radial collateral ligament repaired, joint stabilized with a pin (arrow & insert) and skin incision sutured.
    Right thumb MP joint after radial collateral ligament repaired, joint stabilized with a pin (arrow & insert) and skin incision sutured.
Complications

Infection

  • Stiffness
  • Thumb MP flexion deformity
  • Osteoarthritis
  • Thumb MP joint contracture
  • Impaired grip/pinch strength
  • According to some authors, most complications are due to over-treatment—such as extended periods of immobilization—rather than the absence of treatment.18
  • Failure to initially treat a completely torn collateral ligament of the MP joint may result in chronic pain, instability, deformity, weakness, and/or osteoarthritis. Late ligament repair or reconstruction may be needed to resolve these cases.15
Outcomes
  • When treated early and appropriately, ligamentous injuries to the thumb MP joint typically have a good to excellent prognosis, and most patients will eventually regain thumb functional range of motion, grip strength and pinch strength.1,3,19,20
  • Conservative treatment for MP joint sprains, partial-thickness tears, and minimally displaced full-thickness tears is associated with favorable results.20
  • Ligamentous thumb MP joint injuries that are older than 3 weeks are generally associated with poor outcomes when surgically repaired, which is presumably due to attenuation of the remnant ligament.1
  • Other studies have shown that early surgical treatment of thumb MP joint instability provides good or very good functional outcomes in over 90% of patients, regardless of the technique used. On the other hand, a delayed diagnosis or inappropriate treatment can lead to chronic instability, for which optimal surgical management remains debated.19
Key Educational Points
  • The fingers pinch and grip against the thumb which acts as a mechanical anatomic post.  The thumb can forfill this function without a full range of motion.  Therefore, a stiff thumb MP joint is not usually a functional problem. Even normal thumb MP joints can have an arc of motion that is les than 30 degrees.
  • Complete minimally displaced RCL injuries can heal with 6 weeks of casting without surgical intervention. 
  • Many patients present several weeks or months after injury, at which point they still experience pain, swelling, and stiffness. This can lead some patients to protect the thumb excessively, which results in additional stiffness and hinders their recovery.21
  • Patients, athletic trainers, and coaches sometimes overlook MP joint injuries, and delayed or improper treatment often occurs as a result, which can lead to permanent problems of the affected thumb.10
  • Stress test of the RCL is the most important test for evaluating the stability and integrity of the RC ligament.1
  • The thumb’s wide ROM in multiple directions is a unique characteristic that is largely responsible for the hand’s manifold abilities, but this mobility comes at the expense of stability, and is one of the main reasons the thumb MP joint is injured so frequently.22
  • The rationale for conservative treatment of grade 3 tears is that there is no interposing aponeurosis that interferes with ligament healing, yet most experts still recommend surgery for these injuries, since acute unstable injuries may lead to late symptomatic instability and possibly degenerative joint disease.8
  • Pain without laxity may indicate ligament attenuation or a grade 1 injury, while pain with laxity and an end point may indicate a grade 2 injury, and laxity and lack of an end point are indicative of a grade 3 injury.15Differentiating between partial tears/sprains and complete ruptures is extremely important before determining the optimal treatment course.5
  • Routine X-rays - some experts recommend taking radiographs before stress testing.15thumb MP joint sprains are often missed on X-rays, so clinical suspicion should remain high with injuries to this area.2
  • Ultrasound - has become increasingly effective at imaging the articular surface and associated soft tissues of the fingers, in part because it allows for dynamic evaluation.16  Collateral ligaments normally appear as thick fibrillar or echoic bands, while sprains appear as a diffusely swollen hypoechoic ligament with loss of normal ligament fibrous structure.3,9  Other findings for ligamentous injuries include frank ligament discontinuity or detachment, ligament thickening, and extracapsular leakage of joint fluid.16
References

New and Cited Articles

  1. Avery, DM, 3rd, Caggiano, NM and Matullo, KS. Ulnar collateral ligament injuries of the thumb: a comprehensive review. Orthop Clin North Am 2015;46(2):281-92. PMID: 25771322
  2. Folk, B. Traumatic thumb injury management using mobilization with movement. Man Ther 2001;6(3):178-82. PMID: 11527458
  3. Draghi, F, Gitto, S and Bianchi, S. Injuries to the Collateral Ligaments of the Metacarpophalangeal and Interphalangeal Joints: Sonographic Appearance. J Ultrasound Med 2018;37(9):2117-2133. PMID: 29480577
  4. Coyle, MP, Jr. Grade III radial collateral ligament injuries of the thumb metacarpophalangeal joint: treatment by soft tissue advancement and bony reattachment. J Hand Surg Am 2003;28(1):14-20.PMID: 12563632
  5. Owings, FP, Calandruccio, JH and Mauck, BM. Thumb Ligament Injuries in the Athlete. Orthop Clin North Am 2016;47(4):799-807.PMID: 27637666
  6. Bowers, WH, Wolf, JW, Jr., Nehil, JL, et al. The proximal interphalangeal joint volar plate. I. An anatomical and biomechanical study. J Hand Surg Am 1980;5(1):79-88. PMID: 7365222
  7. Bowers, WH. The proximal interphalangeal joint volar plate. II: a clinical study of hyperextension injury. J Hand Surg Am 1981;6(1):77-81.PMID: 7204922
  8. Lee, AT and Carlson, MG. Thumb metacarpophalangeal joint collateral ligament injury management. Hand Clin 2012;28(3):361-70.PMID: 22883882
  9. Rozmaryn, LM. The Collateral Ligament of the Digits of the Hand: Anatomy, Physiology, Biomechanics, Injury, and Treatment. J Hand Surg Am 2017;42(11):904-915. PMID: 29101974
  10. Kamnerdnakta, S, Huetteman, HE and Chung, KC. Complications of Proximal Interphalangeal Joint Injuries: Prevention and Treatment. Hand Clin 2018;34(2):267-288. PMID: 29625645
  11. Ootes, D, Lambers, KT and Ring, DC. The epidemiology of upper extremity injuries presenting to the emergency department in the United States. Hand (N Y) 2012;7(1):18-22. PMID: 23449400
  12. Baskies, MA and Lee, SK. Evaluation and treatment of injuries of the ulnar collateral ligament of the thumb metacarpophalangeal joint. Bull NYU Hosp Jt Dis 2009;67(1):68-74. PMID: 19302060
  13. Delaere, OP, Suttor, PM, Degolla, R, et al. Early surgical treatment for collateral ligament rupture of metacarpophalangeal joints of the fingers. J Hand Surg Am 2003;28(2):309-15. PMID: 12671864
  14. Hinke, DH, Erickson, SJ, Chamoy, L, et al. Ulnar collateral ligament of the thumb: MR findings in cadavers, volunteers, and patients with ligamentous injury (gamekeeper's thumb). AJR Am J Roentgenol1994;163(6):1431-4. PMID: 7992741
  15. Lourie, GM, Gaston, RG and Freeland, AE. Collateral ligament injuries of the metacarpophalangeal joints of the fingers. Hand Clin 2006;22(3):357-64. PMID: 16843801
  16. Prucz, RB and Friedrich, JB. Finger joint injuries. Clin Sports Med 2015;34(1):99-116. PMID: 25455398
  17. Joyce, KM, Joyce, CW, Conroy, F, et al. Proximal interphalangeal joint dislocations and treatment: an evolutionary process. Arch Plast Surg 2014;41(4):394-7. PMID: 25075363
  18. Adi, M, Hidalgo Diaz, JJ, Salazar Botero, S, et al. Results of conservative treatment of volar plate sprains of the proximal interphalangeal joint with and without avulsion fracture. Hand Surg Rehabil 2017;36(1):44-47.PMID: 28137442
  19. Agout, C, Bacle, G, Brunet, J, et al. Chronic instability of the thumb metacarpo-phalangeal joint: Seven-year outcomes of three surgical techniques. Orthop Traumatol Surg Res 2017;103(6):923-926.PMID: 28576699
  20. Ebrahim, FS, De Maeseneer, M, Jager, T, et al. US diagnosis of UCL tears of the thumb and Stener lesions: technique, pattern-based approach, and differential diagnosis. Radiographics 2006;26(4):1007-20. PMID: 16844929
  21. Bot, AG, Bekkers, S, Herndon, JH, et al. Determinants of disability after proximal interphalangeal joint sprain or dislocation. Psychosomatics 2014;55(6):595-601. PMID: 25034813
  22. Gluck, JS, Balutis, EC and Glickel, SZ. Thumb ligament injuries. J Hand Surg Am 2015;40(4):835-42. PMID: 25813924

Reviews

  1. Avery, DM, 3rd, Caggiano, NM and Matullo, KS. Ulnar collateral ligament injuries of the thumb: a comprehensive review. Orthop Clin North Am 2015;46(2):281-92. PMID: 25771322
  2. Gluck, JS, Balutis, EC and Glickel, SZ. Thumb ligament injuries. J Hand Surg Am 2015;40(4):835-42. PMID: 25813924

Classics

  1. Frank WE, Dobyns J. Surgical pathology of collateral ligamentous injuries of the thumb. Clin Orthop Relat Res1972;83:102-14. PMID: 5014798
  2. Massart P, Bèzes H. Severe metacarpophalangeal sprain of the thumb in ski accidents. 125 surgical repairs in group of 340 cases of metacarpophalangeal sprains from ski accidents. Ann Chir Main1984;3(2):101-12. PMID: 6529288
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