Introduction:
Mannerfelt syndrome is caused due to the rupture of the flexuous pollicis longus tendon due to a bony spur in the carpal tunnel. These ruptures caused by the bony spur in the carpal tunnel were also reported in cases of rheumatoid arthritis. The flexuous pollicis longus tendon most commonly undergoes rupture, and Mannerfelt named this lesion. Hence the name Mannerfelt syndrome. Loss of function in Mannerfelt syndrome is not specific. When the flexuous pollicis longus tendon rupture, it has continuity with the peritendinous sheath or a pseudotendon. The individual usually presents with a weak or no flexion of the distal phalanx. Flexon tendon ruptures occur in an ulnar direction affecting the flexuous pollicis longus tendon and the flexor tendons. Surgery is usually the treatment of choice.
What Is the Cause of Mannerfelt Syndrome?
In rheumatoid arthritis cases, the intercarpal ligaments lose their strength which causes the carpal flexors to exert a continuous pull, leading to volar subluxation of the carpal bones. Destructive rheumatoid arthritis follows the supplying vessels, leading to erosion of the distal volar scaphoid and the proximal volar trapezium.
Bony tissues in between the erosions cause sharp bony spurs, which further weekend the carpal tunnel floor and causes the attrition of the flexor tendons. The scaphoid spur causes the rupture of the flexuous pollicis longus tendon. The common rupture sites are scaphoid, trapezium, distal ulna, hamate, lunate, distal radius, and ulnar sesamoid.
What Is the Prognosis for Mannerfelt Syndrome?
The prognosis is assessed by the individuals who underwent ring finger flexor digitorum sublimis transfer to repair irreplaceable lesions of the flexuous pollicis longus tendon. If interphalangeal joint motion returns, then the prognosis is considered good. Complications are minimal, although tendon reconstruction rupture or interphalangeal fusion may occur.
What Are the Symptoms of Mannerfelt Syndrome?
The individuals affected with Mannerfelt syndrome often have a medical history of rheumatoid arthritis. The flexuous pollicis longus tendon is the only muscle to flex the interphalangeal joint of the thumb; because of this, the Mannerfelt lesion is readily apparent on physical examination.
When the health care provider stabilizes the metacarpophalangeal joint and asks the individual to flex the interphalangeal joint, if the individual is not able to flex the joint, then it indicates rupture. The clinical signs of flexuous pollicis longus tendon rupture and incomplete anterior interosseous nerve paralysis resemble each other. This can be differentiated with a simple test. The health care provider dorsiflexes the individual's wrist. The thumb is hyperextended at the metacarpophalangeal joint and the carpometacarpal joint. If the flexuous pollicis longus tendon is paralyzed but intact, the interphalangeal joint spontaneously flexes and resists the passive extension when examined. The interphalangeal joint remains extended; it indicates a rupture of the flexuous pollicis longus tendon.
How Is Manner Felt Syndrome Diagnosed?
Plain X-rays may reveal gross radiocarpal changes. An axial projection of the carpal tunnel may be challenging due to wrist stiffness. Circular tomography with an angle of 42 degrees was used as linear tomography shows insufficient detail. The tomographic plane is perpendicular to the long axis of the arm, which gives the axial projection of the carpal tunnel.
This method gave access to the carpal tunnel floor, hamate hook, and trapezium aspects. Magnetic resonance imaging provides accurate results and helps in assessing the adjacent tendons. Color Doppler may be used in cases of flexuous pollicis longus tendon attrition.
What Is the Treatment and Management of Mannerfelt Syndrome?
Treatment involves:
Medical Management:
An inflamed tenosynovium is medically managed to reduce pannus and spur formation and the risk of tendon rupture. Once the lesion is identified, surgery is the mode of treatment.
Surgical Management:
Before going ahead with the surgery, the individual is informed about the possibility that one of the construction techniques may be used and surgery does not cure the underlying condition, for example, rheumatoid arthritis. Furthermore, the individual is informed that there may be a recurrence of tenosynovitis and ruptures. An unidentified Mannerfelt lesion is dealt with by the division of the transverse carpal ligament with rheumatoid arthritis.
The bony spur in the carpal tunnel floor is excised after examination, followed by a full flexor tenosynovectomy. The carpal tunnel is thoroughly explored, and tendon repair prevents future ruptures. The bony spur, which causes attrition to the flexuous pollicis longus tendon, can also affect the remaining tendons; hence thorough exploration of the carpal tunnel in individuals with a fused interphalangeal joint is recommended. In functional interphalangeal joints, tendon reconstruction and repair are recommended.
Tendon trans or graft is performed when the distal tendon end is beyond the wrist and can not be reclaimed in the wound. A tendon transfer is also done in the nonfunctioning flexuous pollicis longus muscle. Tendon fusion is the treatment in the interphalangeal joint of the thumb, which is arthritic or unstable. In the proximal palm, a linear incision is placed over the fourth ray and extended across the wrist in a zig-zag manner. Care is taken to avoid the median nerve and its branches (palmar cutaneous and motor). The bony spur is excised, and the adjacent soft tissue is mobilized to cover the exposed bone.
The defect can be covered with the following:
-
Silicone membrane.
-
Transverse carpal ligament flap.
-
Tendon graft.
-
Short bridge tendon graft.
-
Standard full-length tendon graft.
-
Tendon transfer.
Following wound closure, the wrist is held at 15 to 20 degrees flexion and the thumb at 30-degree palmar abduction. A dorsal splint is applied, and a pullout suture is removed after six weeks. A tendon transfer is performed in the nonfunctional flexuous pollicis longus tendon. Tendon transfer has only one juncture site when compared to tendon graft.
Other advantages of tendon transfer include the following:
-
Yields a more viable tendon.
-
No extra procedure is required for graft transfer.
-
Provides motor in flexuous pollicis longus tendon damage.
Conclusion:
Mannerfelt named the lesion, hence the name Mannerfelt syndrome. Mannerfelt syndrome is caused due to the rupture of the flexuous pollicis longus tendon due to a bony spur in the carpal tunnel. It is a rare condition, and treatment involves surgery. However, surgery does not help cure underlying conditions like rheumatoid arthritis.
