Review article
Injuries to the Finger Flexor Pulley System in Rock Climbers: Current Concepts

https://doi.org/10.1016/j.jhsa.2006.02.011Get rights and content

Closed traumatic ruptures of finger flexor tendon pulleys began to be recognized specifically over the past several decades. This injury, although rare in the general population, is seen more commonly in rock climbers. This article analyzes this type of injury and the current diagnostic and therapeutic criteria. Ultrasound and magnetic resonance imaging are used to differentiate between a pulley strain, partial rupture, complete rupture, or multiple ruptures. Grade I to III injuries (strains, partial rupture, single ruptures) are treated conservatively with initial immobilization and early functional therapy under pulley protection. Grade IV injuries (multiple ruptures) require surgical repair.

Section snippets

Anatomy

The finger flexor tendon pulley system performs in combination with the cruciate pulleys as a reinforcing structure of the tendon sheaths, forming a fibro-osseous channel through which the flexor tendons are maintained close to the phalanges. There are 5 annular pulleys (A1–A5) and 3 weaker cruciate pulleys (C1–C3). Great variety in the pulley anatomy can be observed.11, 41, 42, 43 The A2, A3, and A4 pulleys are fairly constant in their occurrence.

Biomechanics

The main function of the pulley system is to maintain the flexor tendons close to the bone, thus converting linear translation and force developed in the flexor muscle–tendon unit into rotation and torque at the finger joints. A loss of 1 or several of the pulleys will cause bowstringing, which leads to a loss of strength and a decreased range of motion.9 These deficits are a function of the specific pulley or pulleys being ruptured. The A1 and A5 pulleys are expendable.44 With respect to the

Injury Patterns

Most injuries to climbers are concentrated on the hand and fingers, with flexor pulley injuries being the most frequent.6, 7, 19, 20, 21, 49, 50, 51 The middle and ring fingers are the most prone to injury.23, 30, 52, 53 This finding is to be expected because the middle finger is used commonly to pull in isolation but seems surprising involving the ring finger. It is understandable if the function of finger crimping during climbing is analyzed further. In climbing there are 2 different general

Clinical Findings

Most climbers report an acute onset of pain while performing a hard move or slipping off a foothold. Sometimes a loud popping noise is noted. There is palpation tenderness on the palmar aspect of the injured pulley, accompanied by swelling and sometimes hematoma. If the patient develops tension in the flexor tendon against resistance then a subluxation of the flexor tendons may be detectable. Visible bowstringing only occurs with multiple pulley ruptures. When the A2 pulley ruptures an

Diagnostics

According to the algorithm and the reports of Gabl et al16 anteroposterior and lateral radiographs always should be performed to exclude fractures or volar plate avulsion injuries and chronic overuse fractures in adolescent climbers. If there also is suspicion of an atraumatic epiphyseal fracture in the face of a negative radiograph then further evaluation through MRI is essential because early stages of epiphyseal injuries sometimes only are visible on MRI sequences.58, 59, 60

The MRI has

Grading

For further scientific evaluation and therapeutic guidelines a grading score was developed (Table 1).21 Grade I injuries are pulley strains with no increased dehiscence of the bone to the tendon on MRI or ultrasound (<2 mm). The complete rupture of an A4 pulley has a very good prognosis, sometimes leading to full recovery within 4 to 6 weeks. This injury has the same general severity as a partial rupture of the more essential A2 or A3 pulleys. These injuries are rated grade II. The complete

Therapy

In 1990 Bollen2 and Tropet et al5 reported on a climber with closed traumatic pulley rupture. Both investigators, Bollen with conservative treatment and Tropet with a surgical procedure, achieved good functional results. Over the past decade further studies about surgical and conservative treatment were reported6, 7, 8, 9, 10, 11, 12, 13, 51 but without general guidelines on treatment. Initially the indication for a surgical repair was more common although currently a nonsurgical approach, at

Conservative Therapy

Based on the biomechanical analyses of Bollen,1 nonsurgical treatment is becoming standard for the single rupture. Bollen1 described a tearing force of 500 N for a 1.5-cm–wide tape above the A2 pulley, which allows good protection of the pulley. Although newer studies by Warme and Brooks70 could not find a different pulley tearing force with or without tape and Schweizer68 could not show the biomechanical benefits of taping, this type of conservative treatment results in very good functional

Surgical Repair

Grade IV injuries require surgical repair to prevent functional deficits.11, 17, 19, 20, 21, 72 Clinically the flexion of the distal interphalangeal joint is reduced and sometimes an extension deficit of the proximal interphalangeal joint occurs.1, 2, 3, 4, 5, 6, 7, 16, 17, 19, 20, 21, 30, 45, 51 The basis for surgical repair are the biomechanical studies of Lin et al26 and the comparison of surgical repairs performed by Widstrom et al.56, 57 A simple suturing of the remaining incomplete rims

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