Mannerfelt Syndrome Treatment & Management

Updated: Apr 26, 2021
  • Author: Dimitrios Danikas, MD, FACS; Chief Editor: Harris Gellman, MD  more...
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Treatment

Medical Care

Medical management of an inflamed tenosynovium may reduce destructive pannus and spur formation and thereby also decrease the risk of tendon rupture. Once a Mannerfelt lesion is identified, surgical treatment is always recommended (see Surgical Care).

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Surgical Care

Before exploration, written informed consent should be obtained. The patient should be informed of the possibility that one of the reconstruction options described below will be needed. The patient should also be informed that the procedure does not cure the underlying problem (eg, rheumatoid arthritis [RA]). Therefore, recurrence of tenosynovitis and additional ruptures are possible.

Division of the transverse carpal ligament in rheumatoid hands is recommended for treatment of an identified Mannerfelt lesion. The surgeon should examine the carpal tunnel floor for bony spurs and excise them. In addition, full flexor tenosynovectomy should be performed. Early tenosynovectomy and removal of bone spurs can prevent tendon attrition.

Exploration of the carpal tunnel is recommended for tendon repair and prevention of further ruptures. Even in patients with a fused interphalangeal (IP) joint, the carpal tunnel should be explored because the bony spur that caused attrition of the flexor pollicis longus (FPL) tendon may affect the remaining flexor tendons.

For a functional IP joint, tendon repair or reconstruction is recommended. When the distal tendon end is beyond the wrist and cannot be retrieved in the wound, a full-length tendon graft or tendon transfer is recommended. A nonfunctioning FPL muscle is an indication for tendon transfer. If the IP joint of the thumb is arthritic or unstable, fusion may be a better procedure for a functional thumb.

A linear incision is made over the fourth ray in the proximal palm and extended across the wrist in a zigzag manner, with care taken to avoid the motor branch and the palmar cutaneous branches of the median nerve. The bony spur is excised from the scaphoid or the trapezium. Adjacent soft tissues are mobilized to cover the exposed bone. The defect can be covered with a silicone membrane, a transverse carpal ligament flap, or a tendon graft. Repair can be done with a short (bridge) tendon graft, a standard full-length tendon graft, or a tendon transfer.

A short tendon graft is recommended when both tendon ends are at the wrist level. This short graft can be obtained from the palmaris longus, the flexor carpi radialis (FCR), or the abductor pollicis longus (APL). [26, 27]  When the distal tendon end is beyond the wrist and cannot be retrieved in the wound, a full-length tendon graft or tendon transfer is recommended.

For a full-length tendon graft, a volar zigzag incision is made on the thumb and extended proximally into the palm. The ruptured distal tendon part is resected, with care taken not to injure any of the pulleys. Through another incision at the distal forearm, the musculotendinous junction of the FPL is identified. The palmaris longus or plantaris tendon is harvested.

With a pediatric feeding tube or a tendon passer, the tendon graft is brought through the sheath and pulleys. The distal end of the graft is attached to the terminal phalanx with a pullout suture or suture anchor. Setting the tendon tension requires positioning the wrist in a neutral position, with the thumb opposed to the index finger and the thumb IP joint at 30° flexion. The proximal end of the graft is then woven into the FPL tendon.

After wound closure, the wrist is kept at 15-20° flexion and the thumb at 30° palmar abduction. A dorsal splint is applied, allowing passive flexion of both thumb joints. After 6 weeks, the pullout suture is removed.

A clear indication for a tendon transfer is a nonfunctioning FPL muscle. Compared with a tendon graft, a tendon transfer has fewer juncture sites (ie, only one), yields a more viable tendon, requires no extra procedure for tendon graft harvest, and provides a motor in cases of direct FPL muscle damage or nerve injury. Possible disadvantages are proximal IP (PIP) joint hyperextension and loss of flexor power in the donor finger. [28]

The flexor digitorum sublimis (FDS) tendon of the long finger is used for a tendon transfer because it is longer than the rest of the flexor tendons and because the ring and small fingers are not impaired. The tendon is distally detached from the middle phalanx of the donor finger, passed under the median nerve, and brought through the tendon sheath and pulleys of the thumb by using a pediatric feeding tube or a tendon passer. The FPL stump is resected, and the underlying volar proximal surface of the distal phalanx is trimmed.

The FDS tendon is secured at the volar aspect of the distal phalanx of the thumb with a pullout suture. A bone anchor can be used instead, also placed in the volar proximal edge of the distal phalanx. A ring- or small-finger sublimis tendon transfer may be considered as an alternative. A flexor tendon tenosynovectomy is performed to prevent further ruptures. The wrist and thumb are immobilized in flexion for 3 weeks, after which passive and gentle active motion is allowed. If a pullout wire is used, it is removed after 6 weeks.

As noted, if the IP joint of the thumb is arthritic or unstable, fusion may be a better procedure for a functional thumb. Arthrodesis of the IP joint of the thumb can provide a strong pinch and improve function. Some authors recommend fusion at 0-5° flexion, whereas others prefer 15-20° flexion. Many fusion techniques with high success rates have been described. [29, 30]

Chong et al described step-cut lengthening of the FPL tendon for the reconstruction of FPL rupture—a single-stage reconstruction that does not require tendon grafting or tendon transfer. [31] This technique has not yet been widely studied.

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