Fractional flexor tendon lengthening for advanced metacarpophalangeal flexion contracture in rheumatoid hands

Fractional Lengthening of Forearm Flexor Tendons: A Cadaveric Biomechanical Analysis

PURPOSE

Multiple procedures have been described for wrist and finger flexion contractures and spasticity. Fractional lengthening of forearm flexor tendons involves making parallel transverse tenotomies at the musculotendinous junction to elongate the muscle. Currently, there is limited literature to define the biomechanical consequences of this lengthening technique.

METHODS

Forty-eight flexor tendons were harvested from eight paired upper limbs including flexor carpi radialis, flexor carpi ulnaris, flexor pollicis longus, and flexor digitorum superficialis tendons. Each tendon that was lengthened was paired with the contralateral tendon as a control. A pair of transverse tenotomies were completed for the fractional lengthening. The first tenotomy was performed at the musculotendinous junction where the tendon narrowed to 75% of its maximal width. The second tenotomy was made 1 cm distal to the first. Tendon length was measured before and after fractional lengthening at a constant resting tension of 1 N. The maximum load at failure of each tendon and the mechanism of failure were each measured and compared with the contralateral side.

RESULTS

After fractional lengthening, the mean increase in resting tendon length was 4 mm. When loaded to failure, the mean maximum load of fractionally lengthened tendons was 42% of the mean maximum load of intact tendons. All lengthened tendons failed at the distal tenotomy site.

CONCLUSIONS

Fractional lengthening resulted in an increase of 3-6 mm (mean: 4 mm) in tendon length at resting tension. There was a significant loss in tensile strength and load to failure following fractional lengthening compared with an intact musculotendinous unit.

CLINICAL RELEVANCE

The reduction in tensile strength following fractional lengthening results in loads at failure that are, in some cases, lower than the estimated forces required to perform basic tasks. Caution during the healing and rehabilitation period is warranted.

Reconstruction of a Chronic Volkmann Contracture following Forearm Revascularization with Burkhalter's Procedure and Fractional Flexor Tendon Lengthening after a Failed Stiles-Bunnell Transfer

Volkmann ischemic contracture is a cause of limb dysfunction that can lead to varying amounts of limb deformity, stiffness, and paralysis. Several procedures have been used to improve limb function in these patients. An 11-year-old male patient sustained a domestic accident with a glass door, resulting in a severe soft tissue trauma to his proximal third of the right forearm with damage to flexor muscles and tendons, complete section of median and ulnar nerves, and radial and ulnar arteries. He was submitted to immediate repair of the radial artery and median and ulnar nerves. Ulnar artery was not repairable due to extensive soft tissue loss. Despite surgical treatment and successful revascularization, postoperatively he developed a postreperfusion syndrome, and in consequence an ischemic contracture. To improve his condition, simultaneous Burkhalter's procedure and fractional flexor tendon lengthening were used after a previous failed Stiles-Bunnell transfer. After 6 months, a good result was obtained, with restoration of a more anatomical hand rest position, improved arc of motion, and significant improvement of hand function with DASH (Disabilities of the Arm, Shoulder and Hand) score improving from 59 to 43 despite a slight reduction in grip strength. Opposition to the ring or little finger tip with the interphalangeal joint (IPJ) of the thumb extended was observed. The combination of fractional flexor tendon lengthening and Burkhalter's procedure is a reliable and simple procedure in cases of Volkmann's ischemic contracture and combined median and ulnar nerve palsy, without significant complications.

Tendon reconstruction for the rheumatoid hand

Tendon involvement in rheumatoid arthritis is frequent and might even be the first sign of the disease. In long-standing untreated conditions, especially in combination with bony erosions, tenosynovitis may lead to tendon fraying and finally tendon rupture. Tendon reconstruction includes tendon grafting and tendon transfer. Direct repair is almost never possible in patients with rheumatoid arthritis, because the inflammatory process produces extensive tendon damage over a long distance. In patients with significant impaired joint function, additional joint treatment should be planned at the same time as tendon reconstruction.