Abstract
Background Flexor pollicis longus (FPL) tendon rupture is a rare complication of scaphoid nonunion.
Case Description A fit active 70-year-old woman ruptured her FPL when it abraded on a painless 50-year-old scaphoid nonunion. She had asymptomatic scaphoid nonunion advanced collapse (SNAC) arthritis. At surgery, the sharp mobile volar scaphoid osteophytes were excised and the volar wrist capsule was repaired. A vascularized fat flap based on a perforator of the radial artery was used to augment the volar wrist capsule repair and to create a smooth gliding surface for the FPL. The ruptured FPL tendon was reconstructed with a palmaris longus graft.
Literature Review Complete rupture of the FPL tendon secondary to scaphoid nonunion is a rare complication. It can be easily misdiagnosed because the original injury may be unrecognized or forgotten. A consensus regarding the optimal surgical management has not been reached.
Clinical Relevance The objective of surgery in this case was to restore FPL function and prevent a recurrent rupture. The asymptomatic SNAC arthritis was not treated. No further wrist surgery was required. The patient was asymptomatic with a functioning FPL tendon 4 years after surgery.
Keywords: flexor pollicis longus, FPL rupture, scaphoid nonunion
Flexor pollicis longus (FPL) tendon rupture is a rare complication of scaphoid nonunion. 1 2 3 4 5 6 7 There is a lack of consensus in the literature on the surgical management of FPL tendon ruptures caused by an asymptomatic scaphoid nonunion and scaphoid nonunion advanced collapse (SNAC) wrists. 2 5 7 We present the case of a fit active 70-year-old woman who ruptured her FPL tendon due to a painless 50-year-old mobile scaphoid nonunion and painless SNAC wrist.
Case Report
A 70-year-old right-hand dominant active female presented 4 weeks after experiencing a loud snap in the thumb and was unable to actively flex the interphalangeal joint (IPJ).She had ruptured her FPL on the sharp palmar edges of a mobile scaphoid nonunion, which had been unsuccessfully bone grafted 50 years previously. Physical examination revealed that the patient was unable to flex the right thumb IPJ. The wrist joint was pain-free, with a full range of motion. An ultrasound demonstrated complete FPL rupture in the vicinity of the nonunited scaphoid ( Fig. 1 ). Radiographs ( Fig. 2 ) and CT scan ( Fig. 3 ) showed a sclerotic mobile nonunion of the waist of the scaphoid. Surgical exposure revealed the mobile sharp edges of the scaphoid nonunion, which had cut and abraded the palmar capsule and the FPL tendon ( Fig. 4 ). At surgery, the sharp mobile volar scaphoid osteophytes were excised and the volar wrist capsule was repaired ( Fig. 5A ). The ruptured tendon was reconstructed with a palmaris longus graft ( Fig. 5B ). A vascularized fat flap based on radial artery perforators was used to augment the volar capsule repair and create a smooth gliding surface for the FPL tendon graft ( Fig. 6A,B ). Postoperative management consisted of a thermoplastic splint and therapy for 8 weeks followed by an exercise program from week 9 to week 12. Four years after the surgery, she was pain-free, with minor loss of active flexion of the IPJ of the thumb ( Fig. 7 ).
Fig. 1.
Complete rupture of the flexor pollicis longus tendon. The tendon gap is estimated at between 6 and 7 cm (interval between the white arrows).
Fig. 2.
( A ) Wrist anteroposterior, ( B ) lateral, ( C ) and lateral in wrist extension radiograph views demonstrate a longstanding nonunion of a prior transverse scaphoid waist fracture with extensive sclerosis and scaphoid nonunion advanced collapse.
Fig. 3.
( A ) Coronal, ( B ) axial, and ( C ) sagittal CT scan views showing the scaphoid nonunion with degenerative changes at the radioscaphoid articulation, the proximal pole of the capitate, and the dorsal aspect of the lunate. ( D ) Volar Spur in the distal aspect of the scaphoid nonunion site (white arrow).
Fig. 4.
( A ) Identification of the distal stump of flexor pollicis longus (FPL) tendon (long black arrow) and volar capsule tear (short black arrow). ( B ) Scaphoid nonunion osteophytes and ( C ) the proximal stump of FPL tendon (long black arrow).
Fig. 5.
( A ) Volar capsule repair ( black arrow ) ( B ) and flexor pollicis longus repair using a palmaris longus interposition tendon graft.
Fig. 6.
( A ) Fat flap based on a perforator of the radial artery ( black arrow ). ( B ) The final aspect of the volar capsule reinforcement with the vascular fat flap.
Fig. 7.
A 4-year postoperative examination with thumb active interphalangeal flexion ( A ) and an excellent range of motion compared with the contralateral side ( B ).
Discussion
While FPL rupture secondary to scaphoid nonunion has been documented, 1 2 3 4 5 6 7 a consensus on the optimal surgical management has not been reached. We have demonstrated in this report that removing the sharp mobile palmar scaphoid osteophytes and using a vascular pedicled flap to augment the volar wrist capsule repair and create a smooth gliding surface for the FPL tendon graft can restore tendon function without the need to treat the asymptomatic scaphoid nonunion and pain-free SNAC arthritis.
Moritomo et al in 2008 8 described two different patterns of interfragmentary motion of the nonunited scaphoid bones: the stable scaphoid nonunion type and the mobile scaphoid nonunion type. This case highlights the possibility of late tendon ruptures in the presence of a mobile scaphoid nonunion. The time delay between scaphoid fracture and FPL rupture ranges from 30 to 60 years. 5 In this case, the delay between the scaphoid fracture and the rupture of the FPL was 50 years.
The question considered at the time of planning surgery was if the asymptomatic scaphoid nonunion and asymptomatic SNAC arthritis should be treated at the same time the FPL tendon was grafted. The concern was that if the scaphoid nonunion was not surgically corrected, the FPL tendon graft would be at a risk of late rupture.
Published options to manage scaphoid nonunion with FPL rupture include no bone procedures, excision of the proximal pole of the scaphoid, spur or osteophyte resection, and bone graft with internal fixation of the scaphoid ( Table 1 ). 1 2 4 5 6 7
Table 1. Surgical management of FPL rupture and associated injuries due to scaphoid nonunion.
| Authors | Cases | Wrist pain | FPL | Associated injuries | Wrist |
|---|---|---|---|---|---|
| Mahring et al 1 | 1 | Yes | FPL tenodesis | Osteophyte removal + volar capsule repair | |
| Thomsen and Falstie-Jensen 2 | 1 | No | FPL direct repair | Index finger FDP frayed portion excision | Volar capsule repair |
| Cross 6 | 1 | Yes | FPL direct repair | Scaphoid proximal pole excision + volar capsule repair | |
| Saitoh et al 4 | 4 | Yes | FPL repair with tendon graft | Scaphoid osteosynthesis + iliac bone graft | |
| Yes | FPL repair with tendon graft | Scaphoid osteosynthesis + iliac bone graft | |||
| Yes | FPL repair with tendon graft | Scaphoid osteosynthesis + iliac bone graft | |||
| Yes | Refused surgery | Refused surgery | |||
| Wacker et al 7 | 1 | No | Thumb IPJ fusion | Distal Index finger FDP tenodesis to middle finger FDP | Osteophyte removal + capsular flap |
| Pierrart et al 5 | 1 | No | Ring finger FDS transfer to FPL | Index finger FDP frayed portion excision | Osteophyte removal + capsular flap |
Abbreviations: FDP, flexor digitorum profundus; FDS, flexor digitorum superficialis; FPL, flexor pollicis longus; IPJ, interphalangeal joint.
Prior to surgery, the patient had a pain-free range of wrist motion and had no desire to have a bone graft with internal fixation of the scaphoid or partial wrist fusion. As such, treatment focused on reconstructing the FPL tendon without addressing the asymptomatic scaphoid nonunion and SNAC wrist.
The surgical options to manage the FPL tendon rupture in the literature include tendon graft, tenodesis, direct repair, and IPJ fusion ( Table 1 ). 1 2 4 5 6 7 In this case, the FPL tendon was reconstructed with an ipsilateral palmaris longus tendon graft.
This case report contributes to the small amount of information in the literature on this rare cause of attrition rupture of the FPL tendon. The asymptomatic mobile scaphoid nonunion does not need to be bone grafted and internally fixed to obtain a satisfactory outcome.
Footnotes
Conflict of Interest None declared.
References
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