Motion and morphology of the thumb metacarpophalangeal joint

PURPOSE: To determine the variability in the flexion/extension motion of the thumb metacarpophalangeal (MCP) joint in a normal volunteer population and to determine any correlation between the shape of the thumb metacarpal head, gender, age, thumb interphalangeal (IP) joint range of motion (ROM), and thumb MCP joint ROM in a population of fresh-frozen cadaver arms. METHODS: The ROM of the thumb MCP joints of 100 volunteers (200 thumbs) was measured. The thumb MCP joints of 70 fresh-frozen cadaver arms were examined. Posteroanterior and lateral radiographs were taken of 64 MCP joints. Passive flexion and extension at the MCP and IP joints were measured with a standard goniometer starting at neutral (0 degrees ) with the metacarpal, proximal, and distal phalanges axially aligned. The distance from the volar to the dorsal edge of the articular surface (A) and the radius of curvature of the articular surface (r) of the metacarpal head were measured on the lateral view. The shape of the metacarpal head was given a value using the A/r ratio. Regression analysis was used to determine the correlation between the head shape and joint motion. The thumbs were categorized into a round group (A/r ratio > 1.7) or a flat group (A/r ratio of < 1.7) to facilitate statistical analysis. RESULTS: The volunteer population mean thumb MCP maximum flexion was 77 degrees range, 40 degrees -126 degrees ). Range of motion in hyperextension varied from 0 degrees to 72 degrees, with a mean of 35 degrees. Total ROM was from 55 degrees to 176 degrees, with a mean of 110 degrees. In the cadaver population studied the average MCP joint ROM was 94 degrees (mean flexion, 70 degrees; mean extension, 24 degrees ). The A/r ratio had a range of 1.1 to 2.2. There were 37 round and 27 flat thumb metacarpal heads. Regression analysis showed a significant correlation between metacarpal head shape and ROM; MCP joints with rounder metacarpal heads had greater motion. Round and flat metacarpal heads had significantly different motion arcs averaging 106 degrees and 77 degrees, respectively. Female gender was associated both with significantly greater MCP joint ROM (99 degrees women/87 degrees men) and a significantly higher incidence of round metacarpal heads (66% of women/36% of men). No significant correlation existed between specimen age, MCP, and/or IP joint ROM. CONCLUSIONS: There is a wide range in the magnitude of the thumb MCP joint ROM and the normal shape (round vs flat) of the thumb metacarpal head. A rounder thumb metacarpal head has greater thumb MCP joint ROM than a flatter thumb metacarpal head. Clinically we have found this information helpful in predicting posttraumatic recovery of thumb MCP joint ROM and selecting candidates for and predicting patient satisfaction with thumb MCP joint arthrodesis.     

Dislocations and fracture dislocations of the tarsometatarsal joints

Dislocations and fracture-dislocations of the tarsometatarsal joints are potentially disabling injuries that present challenging therapeutic problems. Early recognition is imperative and is based on a familiarity with the important anatomic features of this joint, mechanism of injury, and subtle radiographic changes that often accompany these lesions. Following injury, a precise anatomic reduction of the tarsometatarsal joint is critical if long-term disability is to be avoided. There appears to be a direct correlation between achieving an accurate reduction and a satisfactory clinical result. In our experience, surgical reduction offers the most effective and reliable means of achieving this goal. We have presented an approach for the management of these lesions, which we believe offers advantages over previously described techniques. Our experience has shown that accurate anatomic operative reduction and rigid internal fixation provide an increased assurance of a pain-free, durable, and functional foot in the great majority of cases.     

Traumatic thumb carpometacarpal joint dislocations

Isolated traumatic dislocation of the thumb carpometacarpal joint, also called the trapeziometacarpal joint, is a rare injury. Controversy still exists concerning which ligaments are the true key stabilizers for the joint and therefore need to be damaged to result in dislocation, and optimal treatment strategies for thumb carpometacarpal joint dislocations are the subject of continuing debate. We give a review of the literature concerning traumatic dislocations of the carpometacarpal joint of the thumb and propose a treatment algorithm.     

Ulnar instability of the metacarpophalangeal joint of thumb

A method of reconstruction of the long standing rupture of ulnar collateral ligament of the thumb is described. Its advantage is the tightness with which the tendon used for repair can be sutured to achieve maximum stability. This has been used in eight patients in the past four years and provided a stable and painless thumb.     

Collateral ligament injuries of the thumb metacarpophalangeal joint

The ulnar and radial collateral ligaments are primary stabilizers of the thumb metacarpophalangeal (MP) joint. Injury to these ligaments can lead to instability and disability. Stress testing is essential to establish the diagnosis. Complete tear is diagnosed on physical examination when the proximal phalanx of the thumb can be angulated ulnarly or radially on the metacarpal head by 30° to 35° with the MP joint in either zero degrees of extension or 30° of flexion. Lack of a firm end point or angulation measuring >15° on stress testing compared with the contralateral thumb MP joint are also indicative of complete tear. Partial ligament injuries may be managed nonsurgically, but complete tears are usually managed surgically. Various techniques are used to reattach the ligament to bone, including suture anchors and, less commonly, repair of midsubstance tears. Options for managing chronic injuries include ligament repair, ligament reconstruction with a free tendon graft, and arthrodesis of the MP joint.     

Treatment of thumb metacarpophalangeal and interphalangeal joint arthritis

Degenerative joint disease affecting the thumb metacarpophalangeal and interphalangeal joints is a debilitating condition, which can significantly restrict activities of daily living. Conservative measures to address symptoms include oral anti-inflammatory medications, activity modification and splinting, and intraarticular corticosteroid injections. Surgical interventions include arthroscopic synovectomy, arthroplasty, and finally arthrodesis of the affected articulations. Although short-term results from synovectomy and arthroplasty seem promising, long-term data are not yet available. Arthrodesis of the metacarpophalangeal and interphalangeal joints yields a stable yet functional thumb with reliably good pain relief.     

A metacarpophalangeal joint stabilization splint: the Galindo-Lim thumb metacarpophalangeal joint stabilization splint.

Creation of a splint should allow for maximal functional use of the hand as well as comfort. The design of the Galindo-Lim splint enhances functional use of the hand not only because it stabilizes the MCP joint but also because it does not cross the wrist crease, thus allowing full wrist motion. Independence in the performance of daily activities is easily achieved with the Galindo-Lim splint (Figure 5). The splint is appropriate for patients with a variety of diagnoses, including MCP joint volar plate injuries, collateral ligament injuries, joint hypermobility, and arthritic conditions.     

Ligament injuries of the metacarpophalangeal joint of the thumb

When it comes to injuries of the collateral ligament in the metacarpal-phalangeal joint of the thumb, the best results have proved to be obtainable from primary surgery. Secondary ligament surgery according to Strandel, in its modification by B?uerle and Reill, has its clear-cut indication and ensures restoration of thumb functionality. Arthrodesis is an alternative that should be chosen with generosity.     

Implant arthroplasty of the metacarpophalangeal joint of the thumb

Thumb metacarpophalangeal arthritis may affect overall hand function more than expected because pain and instability compromise pinch and grip strength. Implant arthroplasty represents one option in the treatment of deformity, destruction, and instability at the metacarpophalangeal joint level. Appropriate use of implant arthroplasty requires careful evaluation of the overall deformity and the status of the interphalangeal joint. If the interphalangeal joint is likely to require fusion--either simultaneous with metacarpophalangeal surgery or subsequently--then implant arthroplasty may be the best treatment option for the metacarpophalangeal joint.     

A splint for the metacarpophalangeal joint of the thumb

We describe an effective splint for sprains of the metacarpophalangeal joint of the thumb.     

Posttraumatic sesamoid arthritis of the metacarpophalangeal joint of the thumb

The articular interface between the radial sesamoid and the radial condyle of the metacarpal head, which is the radial subsesamoid joint, is the most frequently involved area of abnormality in the metacarpophalangeal joint complex. More than 85% of all adult cadavers demonstrate degenerative arthritis of the radial subsesamoid joint. Confusing this condition with degenerative arthritis of the metacarpophalangeal joint may lead to unnecessary joint fusions. The predisposition of the radial subsesamoid to degenerative arthritis is related to the asymmetry of the palmar condyles of the metacarpal. The ulnar sesamoid has a flatter and broader condyle compared with the radial sesamoid, which rides on a high, narrow ridge. Thirty-six patients with symptomatic sesamoiditis have been treated by sesamoidectomy since 1978. Twenty-one of these patients were available for follow-up examination between 1 and 5 years after surgery, and 19 had relief of proximal thumb pain after sesamoidectomy.     

Ultrasonographic stress test of the metacarpophalangeal joint of the thumb

The purpose of this study was to evaluate functional ultrasound as a tool for detecting an ulnar collateral ligament injury of the thumb. The feasability of using ultrasound for imaging the thumb joint space was tested in a pilot study, using ultrasound and dissection in 14 cadaveric hand specimens. To test this method clinically, both metacarpophalangeal joints of the thumb in 461 healthy volunteers were examined using ultrasound (11 MHz) under radial stress. The distance between the innominate tubercle of the first metacarpal head to the proximal phalanx was measured. The mean distance between the first metacarpal head and the proximal phalanx (n = 461) was 4.5 mm (standard deviation, 0.65 mm) on the right side and 4.6 mm (standard deviation, 0.61 mm) on the left side. These data were compared with data of 25 patients with an operative diagnosis of rupture of the ulnar collateral ligament of the thumb. The difference in joint space between the injured and uninjured sides was 2.25 mm (standard deviation, 0.46 mm). The metacarpophalangeal joint space can be reproducibly detected on high-frequency ultrasound. An increased gap seen on ultrasound is indicative of a rupture of the ulnar collateral ligament of the thumb.     

Vertical locking of the metacarpophalangeal joint of the thumb.

Locking of the metacarpophalangeal (MP) joint of the fingers, though reported infrequently, is not rare in the literature. We will report two rare cases of the MP joint of the thumb locked in 90 degrees of flexion (vertical locking). The first case is a 21-year-old man, punched on his right thumb by his friend, who arrived with his thumb fixed in a flexed position. The X-ray images of the right thumb showed the proximal phalanx subluxation in the palmer side in a vertical position. The second case is a 35-year-old woman with her right thumb accidentally caught in the chain of a key-holder. The locking was easily reduced without anaesthesia in both cases. We assume the mechanism was that the flexion force on the MP joint led to subluxation and the locking occurred due to the tension of the collateral ligament caused by the volar prominence of the radial condyle.