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SPRAIN, THUMB INTERPHALANGEAL (IP) JOINT

Introduction

The interphalangeal (IP) joint of the thumb is extremely stable, and as a result, injuries to this joint are some of the most uncommon of the hand. Ligamentous injuries of the thumb IP joint range from mild sprains to complete ruptures, and the mechanism responsible is usually a hyperextension force to the joint, which may occur in some ball-handling sports or from a fall on an outstretched hand (FOOSH). These injuries typically have an excellent prognosis, but prolonged immobilization of the thumb IP joint can cause stiffness and may result in irreversible loss of motion in the digit. This highlights why a timely and accurate diagnosis and appropriate treatment are needed to prevent long-term complications.1-3

Pathophysiology

  • The mechanism responsible for ligamentous injuries of the thumb IP joint is usually either hyperextension of the joint or a laterally deviating force to the tip of the thumb, such as from a thrown ball in sports or a FOOSH injury. If one of these forces is strong enough, it can completely rupture the volar plate or one of the collateral ligaments.4
  • More complex injuries of the IP joint may be associated with joint effusion, avulsion fractures, dislocations, and various degrees of extensor tendon involvement.1

Related Anatomy5,6

  • Ulnar collateral ligament (UCL): proper and accessory
  • Radial collateral ligament (RCL): proper and accessory
  • Dorsal capsule
  • Volar plate
  • The thumb IP joint is a synovial, uniaxial hinge joint that only allows flexion and extension movements in the sagittal plane. It is the least complex and most stable of the 3 thumb joints, and its marked stability is one of the main reasons the joint is injured so infrequently.1,2
  • Both static and dynamic structures stabilize the thumb IP joint, with static stabilizers including the collateral ligament/volar plate complex and the pulley system. The proper and accessory RCLs and UCLs serve as its primary static stabilizers.1
  • The flexor pollicis longus (FPL) tendon lies between the two sesamoid bones superficial to the volar plate and eventually inserts at the base of the distal phalanx. The FPL tendon is primarily responsible for flexion of the thumb IP joint and to a lesser extent, the thumb metacarpophalangeal (MP) joint.3
  • A single sesamoid bone also may be embedded in the volar plate of the thumb IP joint and in the FPL tendon just proximal to its insertion onto the distal phalanx.3
  • Ligamentous injuries of the thumb IP 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 complete disruption of the collateral ligament, but the volar plate remains intact. There is some instability, but stress testing 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.7,8 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%.9
  • The incidence of finger sprains is 37.3 per 100,000 persons/year, 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 involving the distal interphalangeal (DIP) joint of the fingers and thumb IP joint.9

Differential Diagnosis

  • Collateral ligament tear
  • Volar plate tear
  • Thumb IP joint dislocation
  • Thumb proximal phalanx fracture
  • Thumb distal phalanx fracture
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

Symptoms
History of thumb trauma with thumb IP joint instability and/or deformity
Decreased thumb motion and impaired grip/pinch strength
Pain, swelling, tenderness, and ecchymosis over the thumb IP joint
Typical History

The typical patient is a 17-year-old, left-handed male who plays quarterback for his high school football team. During a game, the ball was snapped to him prematurely, before he was able to place his hands in the proper position to receive the ball. As a result, his thumbs were pointing directly perpendicular the ball as it made its way towards him, and upon contact, the ball hyperextended the IP joint of his left thumb. This force sprained the UCL of the IP joint and caused him to recoil his hand in pain. Swelling and tenderness followed soon thereafter, and since it was his throwing hand, the athlete had to be taken out of the game.

Positive Tests, Exams or Signs
Work-up Options
Images (X-Ray, MRI, etc.)
Thumb IP Injuries
  • Elderly male with a left thumb acute IP dislocation
    Elderly male with a left thumb acute IP dislocation
Treatment Options
Treatment Goals
  • When managing ligamentous injuries of the thumb IP joint, the primary goal is to obtain a strong, stable, and pain-free joint with an optimum ROM.12
Conservative
  • The treatment approach for thumb IP joint sprains and ligament ruptures may vary somewhat from clinician to clinician, but in general, 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 majority of grade 3 injuries may require surgery, with one possible exception being complete ligament ruptures that are minimally displaced.13,14
  • The most important component of immobilization is to protect the thumb IP joint from stress while allowing the thumb MP joint to move freely to avoid stiffness, which can be accomplished with several devices, such as a functional hinged splint or custom thermoplastic splint.13
  • The required duration of immobilization ranges from 10 days to 6 weeks depending on the location, grade, concomitant bone or soft tissue abnormalities, and timing of presentation.1,13
    • Some authors recommend 2 weeks of immobilization for mild grade 1 sprains, while grade 2 sprains may show mild ligamentous laxity and require 2-4 weeks before progressing to exercise. Chronic ligament injuries are more difficult to manage and their outcome is less predictable.14
    • At 4 weeks, occupational or physical therapy to regain ROM can begin, with a particular focus in the flexion/extension plane while avoiding valgus stresses at the thumb IP 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.13
  • Non-steroidal anti-inflammatory drugs should only be used cautiously and for short period of time.7
  • Steroid injections may reduce pain and inflammation, but can be detrimental to healing. Most experts therefore caution against their use for acute thumb IP joint sprains.7
Operative
  • Surgery is usually indicated for grade 2 thumb IP joint injuries with marked instability and most grade 3 injuries, unless the rupture is minimally displaced, in which case conservative treatment may be recommended.11,13
  • Acute, complete ligamentous ruptures <3 weeks old are generally treated with ligament repair, which requires that the native tissue is of adequate length and quality.13
  • Surgical reconstruction is the preferred option for complete ruptures >3 weeks old and for those in which the tissue quality or length is inappropriate for primary repair.13
  • After surgery, the thumb IP joint should be immobilized and the MP joint left free to prevent adhesions. The immobilization device is to be removed at postoperative day 3-5 and replaced by a removable thermoplastic splint until week 4. General activities and strengthening and ROM exercises continue during this time, and a full return to activities is usually permitted at 3 months.13
CPT Codes for Treatment Options

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Common Procedure Name
PIP joint arthroplasty
CPT Description
Arthroplasty, interphalangeal joint with prosthetic implant, each joint
CPT Code Number
26536
CPT Code References

The American Medical Association (AMA) and Hand Surgery Resource, LLC have entered into a royalty free agreement which allows Hand Surgery Resource to provide our users with 75 commonly used hand surgery related CPT Codes for educational promises. For procedures associated with this Diagnostic Guide the CPT Codes are provided above. Reference materials for these codes is provided below. If the CPT Codes for the for the procedures associated with this Diagnostic Guide are not listed, then Hand Surgery Resource recommends using the references below to identify the proper CPT Codes.

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Complications

Infection

  • Stiffness
  • Thumb IP joint flexion deformity
  • Osteoarthritis
  • Thumb IP 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.15
  • Failure to initially repair a completely torn collateral ligament of the IP joint may result in chronic pain, instability, deformity, weakness, and/or osteoarthritis. Late ligament repair or reconstruction may be needed to resolve these cases.10
Outcomes
  • When treated appropriately, ligamentous injuries to the thumb IP joint typically have a good to excellent prognosis, and most patients will eventually regain their thumb ROM and grip and pinch strength.1,13
    • One of the primary predictors of success is the promptness of treatment, as injuries managed early are typically associated with more positive outcomes.1
Key Educational Points
  • 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 finger excessively, which results in additional stiffness and hinders their recovery.16
  • Patients, athletic trainers, and coaches often overlook thumb IP joint injuries, and delayed or improper treatment often occurs as a result, which can lead to permanent thumb deformities.8
  • No structure in the human body has an anatomy as intricate or a ROM as complex as the thumb, and the opposable thumb is one of the defining traits of our species. Patients without functioning thumbs have severe functional impairments that make it difficult to navigate the world around them. This underscores the importance of effectively managing and completely rehabilitating all ligamentous thumb IP joint injuries.3
  • Specific treatment protocols for thumb IP joint injuries are lacking due to their low incidence rates and scarcity of applicable research, so most recommendations are based on guidelines for other ligamentous injuries of the thumb and fingers.3
  • Routine X-rays - some experts recommend taking radiographs before stress testing.10  Standard posteroanterior (PA) and true lateral views are helpful for ruling out an associated fracture in thumb injuries.11
  • Ultrasound - increasingly affective at imaging the articular surface and associated soft tissues of the fingers and thumb, in part because it allows for dynamic evaluation.4  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.1,7  Other findings for ligamentous injuries include frank ligament discontinuity or detachment, ligament thickening, and extracapsular leakage of joint fluid.4
  • MRI - may be useful for detecting torn ligaments, but may not detect ligaments that are lax or stretched.7
References

New and Cited Articles

  1. 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
  2. Gluck, JS, Balutis, EC and Glickel, SZ. Thumb ligament injuries. J Hand Surg Am 2015;40(4):835-42. PMID: 25813924
  3. Rawat, U, Pierce, JL, Evans, S, et al. High-Resolution MR Imaging and US Anatomy of the Thumb. Radiographics 2016;36(6):1701-1716.PMID: 27726751
  4. Prucz, RB and Friedrich, JB. Finger joint injuries. Clin Sports Med 2015;34(1):99-116. PMID: 25455398
  5. 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
  6. 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
  7. 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
  8. 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
  9. 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
  10. 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
  11. Owings, FP, Calandruccio, JH and Mauck, BM. Thumb Ligament Injuries in the Athlete. Orthop Clin North Am 2016;47(4):799-807.PMID: 27637666
  12. 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
  13. 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
  14. Folk, B. Traumatic thumb injury management using mobilization with movement. Man Ther 2001;6(3):178-82. PMID: 11527458
  15. 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
  16. 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

Review

  1. Gluck, JS, Balutis, EC and Glickel, SZ. Thumb ligament injuries. J Hand Surg Am 2015;40(4):835-42. PMID: 25813924

Classic

  1. Frank WE, Dobyns J. Surgical pathology of collateral ligamentous injuries of the thumb. Clin Orthop Relat Res1972;83:102-14. PMID: 5014798
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