eMedicine Specialties > Orthopedic Surgery > Hand & Upper Extremity

Mannerfelt Syndrome

Author: Dimitrios Danikas, MD, Attending Plastic Surgeon, Bayhealth Medical Center
Coauthor(s): Michael Neumeister, MD, FRCSC, Professor & Chairman - FACS - Director Hand/Microsurgery Fellowship - Division of Plastic Surgery, Southern Illinois University School of Medicine; Richard Brown, MD, FACS, Clinical Professor, Department of Surgery, Division of Plastic and Reconstructive Surgery, Southern Illinois University School of Medicine
Contributor Information and Disclosures

Updated: Jun 11, 2008

Introduction

Mannerfelt syndrome refers to rupture of the flexor pollicis longus tendon from attrition caused by a bony spur in the carpal tunnel.

In 1891, von Zander first presented flexor pollicis longus tendon rupture from tenosynovitis as drummer's palsy.¹ In 1949, James reported a flexor tendon rupture from a sharp bony spicule that had pierced through the carpal tunnel floor in a patient with Kienböck disease.² Laine and Vainio reported spontaneous flexor tendon ruptures in rheumatoid arthritis.³ Linscheid and Lipscomb described flexor pollicis longus tendon rupture at the insertion into the distal phalanx, under the annular ligament and at the junction with the muscle in rheumatoid hands.⁴ Fowler suggested that attrition flexor tendon rupture is related to the hook of the hamate and the trapezium.⁵ Lipscomb believed that flexor tendon ruptures occur where synovial membrane is present as in the carpal tunnel and along the digits.⁶

Finally, in 1969, Mannerfelt published his series of attrition flexor tendon ruptures in rheumatoid arthritis caused by bony spurs in the carpal tunnel.⁷ Flexor pollicis longus tendon was the most common flexor tendon to rupture from attrition by a bony spur in the carpal tunnel. Thus, this specific lesion was named after Mannerfelt.

Problem

Functional loss is variable. Even if the tendon has ruptured, continuity may exist through the paratendinous sheath or a pseudotendon. The patient presents with weak or no flexion of the distal phalanx (see image below). Flexor tendon ruptures occur consecutively, starting with the flexor pollicis longus and thereafter affecting other flexor tendons in a more ulnar direction.⁸ Bilateral ruptures have been reported.⁹

Frequency

In his series of patients with affected flexor tendons in the carpal tunnel, Mannerfelt reported that 20 of 25 patients had involvement of the flexor pollicis longus tendon and that nearly all flexor tendon attritions occurred in women.⁷

Etiology

Bony spurs between erosions at the distal volar scaphoid and proximal volar trapezium cut through the carpal tunnel floor and lead to attrition of the flexor tendons (see Pathophysiology).

Pathophysiology

The flexor pollicis longus originates from the middle of the anterior surface of the radial shaft, the adjoining part of the interosseous membrane and the coronoid process. It is the most radial tendon in the carpal tunnel. The tendon passes under the transverse carpal ligament, it passes around the hook of the distal scaphoid, and it inserts into the base of the distal phalanx of the thumb, flexing the distal phalanx.

The anterior interosseous branch of the median nerve supplies the flexor pollicis longus. The muscle receives blood supply from radial artery muscle perforators. Within the tendon sheath of the thumb are 2 distinct vincula. Feeding vessels to the trapezium and scaphoid are present on the volar radial aspect of the trapezioscaphoid joint. These vessels course along the trapezioscaphoid ligaments to reach the scaphoid tuberosity.

According to Mannerfelt, in rheumatoid arthritis the intercarpal ligaments lose strength, and the carpal flexors exert a continuous pull, causing volar subluxation of the carpal bones. Destructive rheumatoid inflammatory tissue follows the feeding vessels, causing erosions at the distal volar scaphoid and proximal volar trapezium.¹⁰ Bony tissue between the erosions forms sharp spurs that cut through the weakened carpal tunnel floor and can lead to attrition of flexor tendons (see image below). The flexor pollicis longus tendon is usually ruptured by a scaphoid spur.¹¹ The site of the rupture is usually the scaphoid, followed, in descending order of frequency, by the trapezium, distal ulna, hamate, lunate, distal radius, and ulnar sesamoid.^12,13,14,15

Presentation

The patient usually presents with a history of rheumatoid arthritis and loss of thumb interphalangeal joint flexion. Since the flexor pollicis longus is the only muscle to flex the interphalangeal joint of the thumb, the Mannerfelt lesion is usually clinically apparent on physical examination. The examiner stabilizes the metacarpophalangeal joint, and the patient is asked to flex the interphalangeal joint. In the case of rupture, the patient is unable to flex the distal thumb phalanx or, at most, is able to flex it weakly.

Incomplete anterior interosseous nerve paralysis and rupture of the flexor pollicis longus tendon resemble each other clinically. Mody reported a simple and reliable test to differentiate the 2 conditions.¹⁶ The physician dorsiflexes the patient's wrist. The thumb is hyperextended at both the carpometacarpal and metacarpophalangeal joints. If the flexor pollicis longus is intact but paralyzed, the interphalangeal joint flexes spontaneously. Also, it resists passive extension when tested. If the tendon is ruptured, the interphalangeal joint remains extended.

Indications

Division of transverse carpal ligament in rheumatoid hands is recommended once a Mannerfelt lesion is identified. 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 joint, the carpal tunnel should be explored because the bony spur that caused attrition of the flexor pollicis longus tendon may affect the remaining flexor tendons. Fusion of the interphalangeal joint is performed when the joint is arthritic or unstable.

For a functional interphalangeal 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 flexor pollicis longus muscle is an indication for tendon transfer.

If the interphalangeal joint of the thumb is arthritic or unstable, fusion may be a better procedure for a functional thumb.

Relevant Anatomy

See Treatment, Surgical therapy, below.

Contraindications

Surgical treatment is always recommended once a Mannerfelt lesion is identified. The different treatment options are described in Indications, above.

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