Intrinsic Plus Hand Treatment & Management

Any injury to the hand can lead to intrinsic contracture. ^[15] Early recognition is essential. Efforts must be directed at decreasing edema in the injured hand. Limb elevation is crucial, and care must be taken to avoid applying compressive dressings such as Ace wraps or restrictive circular casts. If these conservative measures fail or if the surgeon notices persistent swelling and pitting edema, increasing median nerve hypesthesia, or poor capillary refill, a quantitative measurement of intracompartmental pressure may be obtained.

Early and acute trauma: interosseus and adductor compartment release

When increased intracompartmental pressures do not respond quickly to conservative measures, the interosseous compartments should be released promptly. Most patients also require release of the adductor pollicis and carpal tunnel. When flexion of the metacarpophalangeal (MCP) joints is limited, Kirschner wires (K-wires) should be used to fix the MCP joints in 60° of flexion to stretch the collateral ligaments.

Late and mild posttraumatic intrinsic contracture: distal intrinsic release

Patients with mild intrinsic muscle contracture may be able to open and close their fingers normally, but they may have persistent limited flexion at the proximal interphalangeal (PIP) joint several months after an injury to the hand or wrist. These patients often have little to no MCP flexion contracture but limited PIP flexion.

In these instances, the edema of the hand causes the collateral ligaments to swell and tighten. Although the intrinsic contracture is mild, the swollen and tight collateral ligaments resist stretching, and the MCP joints are not pulled into flexion. The results of the intrinsic tightness test are positive. For these patients, distal intrinsic release is recommended. In this procedure, the lateral bands and oblique fibers of the distal third of the proximal phalanges are resected. ^[16]

Postoperatively, the MCP joints are splinted in extension (neutral) position for 3 weeks. The interphalangeal (IP) joints are ranged in active and passive flexion/extension exercises to avoid relapse of the deformity. Dynamic splinting in the MCP extension splint, otherwise known as the reverse knuckle-bender splint, is useful in this period.

Late posttraumatic intrinsic contracture with MCP and PIP joint contractures: muscle slide/release

With more severe ischemic contracture of the interossei and lumbricals, flexion contracture occurs at the MCP joints and extension contracture at the IP joints. With extensive edema of the hand, the contracted interossei overcome the resistance of the tightened collateral ligaments and pull the proximal phalanx into flexion. Secondary changes may include contraction of the volar plate and collateral ligaments of the PIP joints. The results of the intrinsic tightness test are positive, and the deformity of the hand is severe.

Extensive release of the dorsal aponeurosis is necessary to correct severe intrinsic muscle contractures that involve both the MCP and the PIP joints. ^[17] Muscle slide may be used if the interossei are fibrotic and tight but have retained some contractility. With more severe ischemic damage, the interossei are often necrotic and nonfunctional. Proximal intrinsic release is indicated, and the lateral tendons of all interossei, including the abductor digiti quinti (ADQ) tendon, are resected at the level of the MCP joints.

The volar plate is also freed of any attachments at the base of the proximal phalanx, and the accessory collateral ligaments may be resected at their insertion into the volar plate. K-wires may be inserted obliquely through the MCP joints to maintain them in maximal extension. If passive PIP joint flexion is still incomplete with the MCP joints in extension, the lateral bands are resected at the distal half of the proximal phalanx.

Postoperatively, the MCP joints are kept in extension for about 3 weeks. After this time, the K-wires usually are removed. Passive and active flexion/extension of the PIP joints should begin on postoperative day 1.

In a case report, Hamada et al described the use of a modified Ilizarov minifixator to correct severe intrinsic plus hand. ^[18]  Although they concluded that this technique could be recommended for severe or neglected hand contractures and deformities on the grounds that it was safe and less invasive, they did not strongly recommend it, and they cautioned that the success of the procedure depended to a large extent on postoperative management and careful evaluation of the hand disorder.

Spastic contracture of interossei: muscle slide

Patients with cerebral palsy, central nervous system (CNS) disease, or stroke may have spastic contracture of the interossei causing disability. ^{[19, 20, 21]} Often, intrinsic muscle spasticity is masked by extrinsic muscle spasticity and is seen several weeks after release of the extrinsic spasticity. After extrinsic release, the hand assumes the intrinsic plus position owing to its intrinsic contractures. The goal of treatment is not to remove the tightened muscles but to weaken them. This can be accomplished by means of muscle slide.

Muscle slide is accomplished via a dorsal approach to protect the palmar blood supply to the intrinsic muscles. The metacarpal origins of all interossei are released subperiosteally. The tendons of the ADQ and the flexor digiti quinti brevis (FDQB) are also usually transected. ^[22] The MCP joints are then extended and the PIP joints flexed, allowing the muscles to advance distally. The hand is then splinted in this claw position for a period of 3 weeks.

In a single-center retrospective review of 50 patients (54 hands) with CNS lesions and contractures of the wrist and extrinsic finger flexor and forearm pronator muscles, Thevenin-Lemoine et al found that the Page-Scaglietti technique (proximal release of extrinsic flexor and pronator muscles) yielded significant improvements in range of motion (ROM) and function as evaluated according to the Zancolli and House classifications. ^[23]