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Clinical Procedures > Musculoskeletal Procedures
Joint Reduction, Thumb Dislocation
Article Last Updated: Jul 26, 2007
AUTHOR AND EDITOR INFORMATION
Section 1 of 13  
Author: James Emanuel Rodriguez MD, Staff Physician, Department of Emergency Medicine, New York University/Bellevue Hospital
James Emanuel Rodriguez, MD, is a member of the following medical societies: American College of Emergency Physicians, American College of Sports Medicine, and Emergency Medicine Residents Association
Coauthor(s):
Moira Davenport, MD, Assistant Professor, Departments of Emergency Medicine and Orthopedic Surgery, Bellevue Hospital Center, Hospital for Joint Diseases, New York University Medical Center, Manhattan Veteran's Affairs Medical Center
Editors: Erik D Schraga, MD, Consulting Staff, Permanente Medical Group, Kaiser Permanente, Santa Clara Medical Center; Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine.com, Inc; Luis M Lovato, MD, Assistant Clinical Professor, David Geffen School of Medicine at UCLA; Director of Critical Care, Department of Emergency Medicine, Olive View/UCLA Medical Center; Gil Z Shlamovitz, MD, Attending Physician, Windham Memorial Community Hospital; Rick Kulkarni, MD, Medical Director, Assistant Professor of Surgery, Section of Emergency Medicine, Yale-New Haven Hospital
Author and Editor Disclosure
Synonyms and related keywords:
thumb dislocation, thumb relocation, thumb reduction, metacarpophalangeal dislocation, metacarpophalangeal relocation, metacarpophalangeal reduction, Stener lesion, Bennett fracture, Rolando fracture, subluxation, interphalangeal dislocation, volar dislocation, thumb joint, MCP, IP, MCP dislocation, IP dislocation, valgus strain
Despite the inherent stability of the joints of the thumb, the vulnerable anatomic position of the first phalangis often subjects the joints to mechanical strain that leads to subluxation or dislocation of the metacarpophalangeal (MCP) and interphalangeal (IP) joints.
Anatomic locations of the joints of the thumb.
The MCP joint of the thumb is a condyloid joint with a structurally stronger capsular ligament apparatus then the other 4 MCP joints of the hand. Most thumb MCP dislocations are dorsal. They are caused by a longitudinal and dorsal stress along the axis of the digit that hyperextends the thumb and tears the volar plate of the joint. An example of this mechanism is a fall onto an outstretched hand (FOOSH) with an impact to the tip of an extended thumb. Volar dislocation of the MCP joint of the thumb is comparatively rare and is associated with tears of both dorsal capsule ligaments and the extensor pollicis brevis (EPB). For this reason, anterior dislocations are often treated with surgical repair of the torn structures, and closed reduction is rarely achieved with adequate postreduction stability. Plain film radiography is the definitive diagnostic modality for joint dislocations of the thumb, serving to describe the geography of the dislocation and to rule out the possibility of coexisting fractures. Intra-articular fractures should be excluded by radiology prior to attempting to reduce a joint in the thumb. These fractures include the Bennett fracture or oblique fracture through the base of the first metacarpal with dislocation of the radial portion of the articular surface. The Rolando fracture is similar to the Bennett fracture except that the fracture at the base of the metacarpal is comminuted with similar dislocation of the fragments. Dislocation of the IP joint occurs to a much lesser extent than dislocation of the MCP joint. These injuries are most commonly dorsal and are often associated with disruption of the overlying skin and soft tissues. Although rare cases of multiple simultaneous thumb joint dislocations, including the IP, MCP, and the proximal carpometacarpal (CMC) or trapeziometacarpal joint, have been reported in the literature, most thumb dislocations involve only a single joint. The existence of multiple thumb joint dislocation injury underscores the necessity of careful radiographic analysis before reduction attempts are made.
- Radiographic evidence of dorsal dislocation of the first metacarpophalangeal (MCP) or interphalangeal (IP) joint with no simultaneous radiographic evidence of intraarticular fracture of the carpals, the first metacarpal, or the first proximal or distal phalanx
- Clinical history and examination consistent with acute dislocation of the MCP or IP joint of the thumb with significant neurovascular deficits on examination that began at any time after the injury (In this emergent scenario, reduction should not be delayed to acquire radiologic assessment.)
Absolute contraindications
- Simultaneous intraarticular fracture of the carpals, the first metacarpal, or the first proximal or distal phalanx
- Epiphyseal plate injury of the carpals, the first metacarpal, or the first proximal or distal phalanx
Relative contraindications - Persistence of nonossified physeal plate in a dislocation that does not reduce with minimal force
- Volar dislocations of the metacarpophalangeal (MCP) or interphalangeal (IP) joint of the first digit
Provide adequate analgesia to the injured thumb by regional injection, and, if necessary, systemic opioids. The median and radial nerves provide sensory innervation to the thumb and may be blocked as follows: - Median nerve blockage is accomplished by injecting 3-5 mL of lidocaine 1% without epinephrine into the nerve distribution at the volar aspect of the wrist. The area of injection is located just deep to the palmaris longus tendon or slightly radial to it, between the palmaris longus and the flexor carpi radialis tendons in a plane just proximal to the proximal palmar crease, at a depth of 1 cm or less. The needle should be inserted perpendicular to the skin and through the flexor retinaculum, but the nerve itself is actually quite superficial.
- Radial nerve blockage is accomplished by injecting 2-5 mL of lidocaine 1% without epinephrine just lateral to the radial artery at the level of the proximal palmar crease and a depth of 0.5 cm. From this initial injection site, another 5-6 mL of local anesthetic is injected in a circumferential arch around the radial half of the wrist to the dorsal midline for the lidocaine to reach the dorsal nerve branches of the radial nerve.
For further detail, see Hand, Anesthesia: Blocks. Take note that ulnar nerve blockage is not necessary for thumb joint reductions.
- Needles, 20 and 25 gauge
- Syringe, 10 mL
- Alcohol wipes
- Lidocaine 1% without epinephrine
- Basin of lukewarm water
- Plaster rolls, 2-3 inch
- Cotton padding for under the cast, 2-3 rolls
- Elastic bandages, 1-2 inch
- Nonsterile gloves
Position the patient’s hand so that the dorsal, radial dorsal surface is facing the physician and the hand is at approximately chest level, within comfortable reach of the physician’s grasp. This may be aided by having the patient rest his or her elbow on a firm flat surface, with the elbow flexing the hand into an upright position. Firmly grasp the patient’s thumb on the distal phalanx when reducing an interphalangeal (IP) dislocation or on the proximal phalanx when reducing a metacarpophalangeal (MCP) dislocation. The physician should use his or her nondominant hand to hold the patient's wrist. Keep the MCP joints of the index through small digits in comfortable extension, and maintain the wrist in passive flexion to relax the tendons. - When reducing a dorsal IP joint dislocation, the IP joint should be held in gentle hyperextension.
- When reducing a dorsal MCP dorsal dislocation, the MCP joint is gently hyperextended and actively held in this position. The objective is to initially exaggerate the injury.
Preparation - Obtain and document a thorough preprocedure history that includes hand dominance, prior injuries, mechanism of trauma, description of presenting symptoms, subjective loss of strength or sensation, and the patient's age in reference to skeletal maturity.
- Remove all rings, jewelry, or potentially constricting objects from the patient’s wrist and all digits of the patient’s hand.
- Perform and document a thorough physical examination, noting ecchymoses, swelling, pallor, abrasions, lacerations, paresthesias, weakness, passive and active range of motion of the metacarpophalangeal (MCP) and interphalangeal (IP) joint of the thumb, and capillary refill of the distal nail bed.
- Obtain prereduction radiographs of the hand including adequate anteroposterior (AP), lateral, and oblique views of the carpometacarpal (CMC), MCP, and IP joints of the first digit. These allow documentation of the presence and direction of the joint dislocation while excluding the presence of a fracture of the carpals, the first metacarpal, or the first proximal or distal phalanx.
- Explain the procedure, benefits, risks, alternatives, and complications to the patient or the patient’s representative and obtain signed informed consent. Ask the patient or the patient’s representative if they would like others to be present for the procedure.
- Supply appropriate anesthesia (see Anesthesia).
- Properly position the patient (see Positioning).
Technique for dorsal dislocations - Apply the following forces to the injury while maintaining the established position of hyperextension.
- While the above forces are being applied, the physician should bring the injured joint into a position of flexion. The act of joint flexion while applying the maneuvers described above reduces the dislocation, thus resolving the injured joint’s deformity and restoring range of motion.
Technique for volar dislocations - The joint is initially held in extreme flexion rather then hyperextension, thus exaggerating the injury.
- Apply distal pressure on the volar base of the distal phalanx for IP dislocations or the proximal phalanx for MCP dislocations.
- Reduction is achieved by moving the dislocated joint into a position of relative extension without hyperextending the joint.
- Reduction of volar MCP and IP dislocations of the thumb are less successful and lead to more complications than do dorsal dislocations.
Postreduction
- Keep the metacarpophalangeal (MCP) joint in flexion and adduction while attempting the reduction. This may aid the effort by relaxing the intrinsic muscles of the thenar eminence as well as the flexor pollicis longus.
- Do not apply longitudinal traction on an MCP dislocation.
- If the attempted reduction is not successful, do not make multiple repeat attempts. The volar plate, a tendon (eg, flexor pollicis longus, flexor pollicis brevis), or a sesamoid bone may be entrapped within the anatomic joint space, and reduction will be impossible without surgery. Seek orthopedic consultation to schedule such a procedure.
- A Stener lesion is a potential first MCP injury that would cause a reduction attempt to be unstable without operative management. This type of MCP dislocation may appear identical to normal dislocations on radiographs but is complicated by a complete tear (third-degree sprain) of the ulnar collateral ligament (UCL) with displacement of the ruptured ligamentous fragment proximal to the adductor aponeurosis. This injury can be detected by the following findings:
- Marked laxity in the relocated MCP joint when valgus pressure is applied
The hand position used for testing if laxity is present with valgus strain of the metacarpophalangeal (MCP) joint. If such laxity is present, this suggests the presence of an ulnar collateral ligament (UCL) tear and indicates the possible existence of a Stener lesion. - A mass near the ulnar side of the metacarpal head that represents the displaced ligament
- A small avulsion fracture at UCL insertion to the metacarpal head
- An MCP reduction that dislocates again with minimal force
- If a Stener lesion is suspected, immobilize the injury in a short-arm thumb spica splint and consult an orthopedist with the goal of scheduling surgical repair of the UCL within 10 days of the injury. This injury does not heal without surgical intervention.
- Patients who present with a mechanism of injury that suggests a large axial load on the thumb are more likely to have a Bennett or Rolando fracture. Particularly careful radiographic exclusion of these fractures is indicated in these patients.
- Adequate closed reduction may be more difficult or impossible to achieve in the following circumstances:
- Patients who present several hours or days after the injury
- Patients with remarkable soft tissue swelling around the injury
- Patients with residual joint instability after reduction
- Patients who lose reduction after it is initially achieved
- Radiographs that show a sesamoid bone lodged in the anatomic joint space
- Dimpling over the thenar eminence from entrapment of the metacarpal head
- Steps that may improve chances of successful reduction include the following:
- Ensuring adequate analgesia
- Using a low-dose anxiolytic, such as a short-acting benzodiazepine
- Repositioning the patient or the physician's hand placements
- Avoid increasing the strength of forces applied to the reduction attempt, since this increases the potential for additional injury.
- Reduction attempts, particularly if performed repeatedly and with large amounts of force, may cause neurovascular injury to the digit. This can be quickly detected by careful reexamination after each reduction attempt. If such a neurovascular injury occurs, emergent consultation with an orthopedist or hand surgeon is paramount. Surgical intervention may be the only option to reverse such an injury.
- Fracture of the first metacarpal, the proximal phalanx, or the distal phalanx may occur with forceful reduction attempts. Although this is a rare occurrence, physicians should search for new fractures on postreduction radiographs, as such fractures may add a new aspect of instability to the injury.
Chudnofsky RC, Byers S. Thumb spica splint. In: Roberts, ed. Clinical Procedures in Emergency Medicine. 4th ed. Elsevier; 2004:997-998.
| Media file 2:
The position of hyperextension used for reduction of a dorsal (IP) dislocation. |
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| Media file 3:
The position of hyperextension used for reduction of a dorsal metacarpophalangeal (MCP) dislocation. |
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| Media file 4:
The hand position used for testing if laxity is present with valgus strain of the metacarpophalangeal (MCP) joint. If such laxity is present, this suggests the presence of an ulnar collateral ligament (UCL) tear and indicates the possible existence of a Stener lesion. |
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Media type: Photo
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- Chudnofsky R, Carl, Byers, Stacie. Splinting Techniques. In: Roberts: Clinical Procedures in Emergency Medicine. 4th ed. Elsevier Mosby Publishing; 2004:997-8.
- Drosos GI, Kayias EH, Tsioros K. "Floating thumb metacarpal" or complete dislocation of the thumb metacarpal: a case report and review of the literature. Injury. May 2004;35(5):545-8. [Medline].
- Hirata H, Takegami K, Nagakura T, Tsujii M, Uchida A. Irreducible volar subluxation of the metacarpophalangeal joint of the thumb. J Hand Surg [Am]. 2004;29(5):921-4. [Medline].
- Hong E. Hand injuries in sports medicine. Prim Care. 2005;32(1):91-103. [Medline].
- Jobe MT, Calandruccio JH. Ch 64. In: Canale ST. Campbell's Operative Orthopaedics. 10th ed. St. Louis, Mo: Mosby Inc; 2003:3490-4.
- Khan AM, Ryan MG, Teplitz GA. Bilateral carpometacarpal dislocations of the thumb. Am J Orthop. Jan 2003;32(1):38-41. [Medline].
- Posner MA. The Hand. In: Scuderi GR, McCann PD. Sports Medicine, A Comprehensive Approach. 2nd ed. Elsevier Mosby Publishing; 2005:299-303.
- Seiler JG. Chapter 12. In: Essentials of Hand Surgery. 3rd ed. Philadelphia, Pa: Lippincott Williams and Wilkins; 2002:90-8.
- Vashista GN, Krishnan KM, Deshmukh SC. Simultaneous dislocations of the carpometacarpal and metacarpophalangeal joints of the thumb. Injury Extra. 2004;35:56-8.
- Verhelle N, Van Ransbeeck H, De Smet L. Irreducible dislocation of the interphalangeal joint of the thumb: a case report. Eur J Emerg Med. Dec 2003;10(4):347-8.
Joint Reduction, Thumb Dislocation excerpt Article Last Updated: Jul 26, 2007
Topic originally published: Jul 26, 2007
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