Brachioradialis tendon transfer and palmaris longus tendon graft for thumb avulsion: A case report and review of literature

Abstract

BACKGROUND

Thumb replantation following complete traumatic avulsion requires complex techniques to restore function, especially in cases of avulsion at the level of the metacarpophalangeal joint (MCP I) and avulsion of the flexor pollicis longus (FPL) at the musculotendinous junction. Possible treatments include direct tendon suture or tendon transfer, most commonly from the ring finger. To optimize function and avoid donor finger complications, we performed thumb replantation with flexion restoration using brachioradialis (BR) tendon transfer with palmaris longus (PL) tendon graft.

CASE SUMMARY

A 20-year-old left-handed male was admitted for a complete traumatic left thumb amputation following an accident while sliding from the top of a handrail. The patient presented with skin and bone avulsion at the MCP I, avulsion of the FPL tendon at the musculotendinous junction (zone 5), avulsion of the extensor pollicis longus tendon (zone T3), and avulsion of the thumb’s collateral arteries and nerves. The patient was treated with two stage thumb repair. The first intervention consisted of thumb replantation with MCP I arthrodesis, resection of avulsed FPL tendon and implantation of a silicone tendon prosthesis. The second intervention consisted of PL tendon graft and BR tendon transfer. Follow-up at 10 months showed good outcomes with active interphalangeal flexion of 70°, grip strength of 45 kg, key pinch strength of 15 kg and two-point discrimination threshold of 4 mm.

CONCLUSION

Flexion restoration after complete thumb amputation with FPL avulsion at the musculotendinous junction can be achieved using BR tendon transfer with PL tendon graft.

Key Words: Brachioradialis tendon transfer; Flexor pollicis longus; Palmaris longus tendon graft; Replantation; Thumb amputation; Thumb avulsion; Case report

Core Tip: Complete traumatic amputation of the thumb, especially when the flexor pollicis longus is avulsed at the musculotendinous junction, requires a complex replantation technique in order to restore function. Possible treatments include direct tendon suture or tendon transfer, most commonly from the ring finger. To optimize functional outcomes and avoid donor finger complications, we propose a new surgical technique with brachioradialis tendon transfer and palmaris longus tendon graft. This technique was able to restore thumb flexion and provide good key pinch strength.

INTRODUCTION

Thumb replantation following complete traumatic avulsion requires complex surgical techniques in order to restore function[1-3]. When thumb avulsion occurs at the metacarpophalangeal joint (MCP I), an arthrodesis of the joint is usually required. In these cases, restoration of the flexor pollicis longus’ (FPL) function is crucial to allow thumb flexion. We present a case of a complete traumatic thumb avulsion at the MCP I with FPL avulsion at the musculotendinous junction. Possible treatments for this injury include direct tendon suture or tendon transfer, most commonly of flexor digitorum superficialis (FDS) tendon from the ring finger[4-6]. Direct tendon suture is the reference technique for treatment of traumatic tendon ruptures[7]. However, when the avulsion occurs at the musculotendinous junction, direct tendon sutures render inferior functional outcomes compared to tendon transfers[4]. Nevertheless, tendon transfers can potentially create donor site morbidity in otherwise healthy fingers[8-11].

Moreover, for optimal function of the thumb, a muscle of adequate strength is needed. We therefore decided to perform thumb replantation with thumb flexion restoration using brachioradialis (BR) tendon transfer with palmaris longus (PL) tendon graft. BR tendon transfer is a widely used technique for the restoration of thumb flexion in patients with median nerve function deficits[12-16]. However, its use in the treatment of traumatic thumb avulsion has not yet been described in the literature. Therefore, the purpose of the present case report was to describe the surgical technique and functional outcomes of BR tendon transfer with PL tendon graft to restore thumb flexion following complete traumatic thumb avulsion. This case report follows the CARE Criteria 2016[17].

CASE PRESENTATION

Chief complaints

A 20-year-old male was admitted to the emergency department of a Hand Trauma Centre for a complete traumatic left thumb avulsion within four hours from the accident, carrying the avulsed thumb.

History of present illness

The complete thumb avulsion occurred while the patient was sliding from the top of a stair handrail, when his left thumb got stuck between the bars of the handrail.

History of past illness

There was none past illness.

Personal and family history

The patient was a left-handed non-smoker in good general health, with no known comorbidities nor current pharmacological treatment.

Physical examination

An initial physical exam revealed complete separation of the left thumb from the hand, with skin and bone avulsion at the MCP I, avulsion of the FPL tendon at the musculotendinous junction (zone 5), avulsion of the extensor pollicis longus (tendon (zone T3), and avulsion of the thumb’s collateral arteries and nerves (Figure 1).

Figure 1 Complete traumatic thumb avulsion. A and B: Complete traumatic thumb avulsion at the metacarpophalangeal joint with the flexor pollicis longus tendon avulsion at the musculotendinous junction, as seen on photographs; C: The hand radiograph taken at the emergency department. Triangle: The base of the proximal phalanx; white arrow: The metacarpophalangeal joint; blue arrow: Flexor pollicis longus tendon; two black arrows: Proper palmar digital nerves of the thumb.

Laboratory examinations

No laboratory examinations.

Imaging examinations

Additionally, an open fracture of the index proximal phalanx was identified on a hand radiograph.

FINAL DIAGNOSIS

Complete left thumb amputation, with skin and bone avulsion at the MCP I, avulsion of the FPL tendon at the musculotendinous junction (zone 5), avulsion of the extensor pollicis longus tendon (zone T3), and avulsion of the thumb’s collateral arteries and nerves (Figure 1). Open fracture of the index proximal phalanx.

TREATMENT

First stage of thumb repair

The patient was treated by a senior hand surgeon within five hours from the accident with replantation of the avulsed thumb. The intervention was performed under regional anaesthesia, with the use of a tourniquet. After wound debridement, arthrodesis of the MCP I was performed with a dorsal plate. The avulsed FPL tendon was resected, and a silicone tendon prosthesis was implanted in the FPL tendon sheath and fixed at the distal phalanx. End-to-side anastomosis was performed to connect the ulnopalmar digital artery of the thumb and the radial artery of the index. A distal branch of the lateral antebrachial cutaneous nerve was harvested to reconstruct the thumb’s radial and ulnar digital nerves, which were then protected with chitosan neurotubes (Reaxon; KeriMedical, Geneva, Switzerland). The tourniquet was deflated at the maximal time of two hours, following which there were signs of good thumb revascularization. The extensor pollicis longus was sutured back together. Three dorsal veins of adequate diameter were identified in the injured thumb and anastomosed with three dorsal veins below the injury level. At the end of the surgery, healthy thumb coloration was observed. Furthermore, the open fracture of the proximal phalanx of the index finger was treated with a dorsal plate and screws.

Post-operative management of the first stage of the repair

The patient was hospitalised for four days, and received postoperative antibioprophylaxis (1 g of oral amoxicillin with clavulanic acid three times per day for a week) and thromboprophylaxis (160 mg oral aspirin once per day for a month), as well as complex regional pain syndrome type I prophylaxis with oral vitamin C (500 mg per day for 45 days)[18,19]. The hand was not immobilised and rehabilitation started on post-operative day 5, under the supervision of a hand therapist. Three months after the replantation, a palmar skin graft was used to ensure complete wound healing. Before the second stage of thumb repair surgery, the patient received one dose of oral vitamin D to promote tendon healing[20].

Second stage of thumb repair

Seven months after the first surgery, the patient underwent the second stage of thumb repair by the same surgeon in an ambulatory setting, using a tourniquet and under regional anaesthesia. Restoration of thumb flexion at the interphalangeal (IP) joint was achieved using BR tendon transfer extended with PL tendon graft. First, the BR tendon was sectioned distally. Then, the distal half of the proximal BR muscle insertion was partially disinserted in order to adjust the tendon position, to allow thumb flexion in the correct axis. Second, the PL tendon graft was harvested and placed in the FPL sheath, after removing the silicone tendon prosthesis. The distal end of the PL tendon graft was fixed to the base of the thumb’s distal phalanx with a transosseous anchor. Finally, the proximal end of the PL tendon graft was fixed to the distal end of the BR tendon using the Pulvertaft weave technique[21]. The tension of the final tendon transfer was verified and deemed optimal.

Post-operative management of the second stage of the repair

The patient received complex regional pain syndrome type I prophylaxis with oral vitamin C as previously described. The hand was not immobilised. Rehabilitation started on post-operative day 3, under the supervision of the same hand therapist. For the first three weeks, rehabilitation included passive mobilisation, “place and hold” exercises and active mobilisation of the wrist and thumb, although simultaneous extension of the wrist and thumb was not allowed. After three weeks, free active mobilisation started, with progressive use of resistance. The rehabilitation protocol followed the standard of care of the surgical department. One year after the first stage of thumb repair, the dorsal plate was removed from the index finger, and another skin graft was used to treat a palmar retraction.

OUTCOME AND FOLLOW-UP

First stage of thumb repair

Control X-ray at 3 months after the first stage of thumb repair showed good consolidation of the MCP I arthrodesis, which is fixed in 30° flexion. Follow-up at 7 months showed partial recovery of passive and active mobility of the trapeziometacarpal joint, complete active IP extension, passive IP flexion of 60° (Figure 2), and recovery of tactile discrimination of both hemi-pulps.

Figure 2 Follow-up at 7 months after the first stage of thumb repair is shown. A: Passive interphalangeal joint flexion of 60°; B: Complete extension.

Second stage of thumb repair

Four months after the second stage of thumb repair, the patient was able to return to work. At 10 months, the patient had no pain at rest or during activities. The QuickDASH score[22] was 20.5 points, and the QuickDASH work module was 37.5 points. Active IP flexion of the operated thumb was 70° (88% of the contralateral thumb), grip strength was 45 kg (82% of the contralateral thumb) and key pinch strength was 15 kg (68% of the contralateral thumb) (Table 1, Figure 3). Range of motion of the trapeziometacarpal joint on the operated side was between 33%-100% of the contralateral thumb. Sensibility of the operated thumb was measured using the Weber two-point discrimination test at 4 mm.

Figure 3 Second stage of thumb repair. A and B: General aspect of thumb and wound healing after the second stage of thumb repair; C: Control radiograph showing good consolidation of the metacarpophalangeal joint arthrodesis, which is fixed in 30° flexion, after the second stage of thumb repair.

Table 1 Functional outcomes 10 months after the second stage of thumb repair.

		Passive			Active
		Operated	Contralateral		Operated	Contralateral
TMC	TAM flexion-extension (°)	80	80	100%1	78	78	100%1
	Extension (cm)2	2.5	4.5	56%1	1	3	33%1
	Abduction (°)	60	80	75%1	45	80	56%1
	Kapandji opposition	10	10	/	9	10	/
IP	Flexion (°)	70	80	88%1	70	80	88%1
Grip strength (kg)		/	/	/	45	55	82%1
Keypinch strength (kg)		/	/	/	15	22	68%1
Weber threshold (mm)		4	3	/	/	/	/

¹Percentage of operated side compared to contralateral side.

²Trapezio-metacarpal joint extension in cm was measured with the palm of the hand flat on the table as the maximum distance between the elevated thumb (active extension) and the table.

TMC: Trapezio-metacarpal joint; TAM: Total active range of motion; IP: Interphalangeal joint.

DISCUSSION

The most important finding of the present case report was that BR tendon transfer with a PL tendon graft restored thumb flexion and provided good functional outcomes, with no complications specific to the new surgical technique. Therefore, this surgical technique can be used for treatment of traumatic thumb avulsion. Furthermore, the present technique has an advantage over other common techniques for the same indication, as it does not require transfer of FDS tendon or flexor digitorum profundus (FDP) tendon from a donor finger, hence avoiding potential donor site morbidity.

BR tendon transfer to the FPL is a well-known surgical technique, often used to treat various aetiologies of median nerve paralysis, such as tetraplegia[12,13,23], brachial plexus injury[14,15], or tumoral resection[16]. However, BR tendon transfer to the FPL has not yet been described in the context of traumatic injuries. Whereas isolated PL tendon graft is a well-known technique for FPL reconstruction[24-28], the combination of BR tendon transfer and PL tendon graft has not yet been described. In the present study, BR tendon transfer was performed in combination with a PL tendon graft, to obtain sufficient tendon length and avoid thumb extension deficit, a possible complication if BR tendon transfer were performed alone. Other tendon transfers used to restore thumb flexion in traumatic thumb injuries include FDS tendon transfers from the ring finger[4-6,29], and more rarely FDS tendon transfers from the middle finger[30] or FDP tendon transfers from the index finger[31]. These transfers have been shown to provide good functional outcomes[4-6,31]. However, studies on thumb flexion restoration using FDS or FDP tendon transfers after complete thumb avulsion do not report on postoperative conditions of the donor finger, which could be affected by stiffness or contracture[8-11], force reduction[32,33] or a quadriga phenomenon[34,35]. Our novel technique has the advantage of avoiding donor site morbidity, but potential risks related to BR tendon transfer and to PL tendon graft. While BR tendon transfer could result in limited wrist mobility and/or reduced strength, PL tendon grafts are often used for a variety of indications[27,28,36,37] without adverse effects to hand and wrist function[38], although, in rare cases, they can lead to wrist flexion contracture[39]. In the present study, no complications were observed.

Thumb repair in the present study was planned as a two-stage intervention. The surgical plan consisted of two options for the second intervention, depending on the functional outcomes following the first one. The surgeon performed a thumb flexion restoration with tendon transfer and tendon graft during the second intervention due to satisfactory IP passive flexion of 60° and recovered thumb sensibility. However, in the event of limited passive IP flexion or severely limited thumb sensibility, the surgeon would have recommended IP arthrodesis. We believe that this technique could be improved by performing direct BR transfer to the distal end of the avulsed FPL tendon during a one-stage surgery. However, if the surgery were performed as a one-stage procedure, it could have been controversial to prescribe immediate thumb rehabilitation, because the sutured extensor tendon needs time to heal. Immediate rehabilitation of the thumb after tendon transfer is preferred since it can provide better functional outcomes[40-42].

Compared to published studies on thumb flexion restoration with tendon transfer or tendon graft, the functional outcomes of the present surgical technique are promising. Active IP flexion seems to be higher than in other studies[4,5,24,27] without IP extension deficit[24,27]. Grip and key pinch strength, as well as sensibility, are satisfactory and comparable between our study and across other studies[4-6,24,27,43,44]. Thumb retropulsion and first webspace opening are smaller in the present study compared to Peters et al[27], though this is probably due to the presence of the MCP I arthrodesis, which was fixed at 30° flexion. There are no studies on this subject reporting hand function using QuickDASH, although two studies reported DASH outcomes[24,27].

The present study has a number of limitations. First, it was necessary to wait eight months between the first and second stage of thumb repair, to evaluate the recovery of thumb sensibility in order to decide on the next intervention, as well as due to delayed wound healing, which required a skin graft. Second, similar studies on traumatic thumb avulsion treated with tendon transfer do not commonly evaluate patient reported outcomes, making it difficult to compare with the current study. Future publications should consider the recommendations of Collins et al[44], and always include both surgeon and patient perspectives. Third, the intervention in the present study was performed by an experienced hand surgeon; therefore, the results may not be attainable by less experienced surgeons. Fourth, the present study reported outcomes of this new surgical technique in only one patient; further studies on larger cohorts are needed to confirm the generalizability of our findings.

CONCLUSION

Flexion restoration after complete traumatic thumb amputation with FPL avulsion at the musculotendinous junction can be achieved using BR tendon transfer with PL tendon graft.