Coverage of Fingertip Traumatic Amputation in Lesser Digits With Modified Volar Advancement Flap

Abstract

Introduction:

The Moberg volar advancement flap was classically described for covering thumb defects following traumatic fingertip amputations. However, its use in the lesser digits has been rarely reported. This study aims to evaluate the clinical outcomes of a modified volar advancement flap for fingertip amputations in lesser digits.

Methods:

A single-center retrospective review was conducted on patients who underwent a modified volar advancement flap for fingertip amputation reconstruction of the lesser digits between 2015 and 2021. Patients who had flaps performed for the thumb, nontraumatic causes (eg, infection or gangrene), or who defaulted on postoperative rehabilitation and follow-up were excluded.

Results:

Eighteen patients met the inclusion criteria for analysis, with a mean follow-up duration of 6 months. Protective sensation was achieved in 75% of patients, whereas 43.8% regained normal sensation. The mean QuickDASH score was 4.22 ± 5.97 (range 0 to 18.18). Common complications included hypersensitivity (61.1%), infection (11.1%), wound dehiscence (11.1%), and fixed flexion deformity of the distal interphalangeal joint (7.1%). No cases of flap necrosis or dorsal skin necrosis were observed.

Conclusion:

The modified volar advancement flap remains a feasible option for reconstructing fingertip amputations, even in the lesser digits. This technique does not require microsurgical expertise and can be safely performed by general orthopaedic surgeons.

Fingertip amputations are common traumatic injuries in the hand that could result from industrial or household accidents. Proper management of these injuries is critical, as they can lead to functional impairment and aesthetic concerns.¹ These fingertip amputation wounds can be treated conservatively with standard wound dressings, but recovery often takes time with a mean healing time of 4 weeks.² Supplemental surgical interventions are sometimes also required to optimize healing.³ Local flap coverage has emerged as a popular method in reconstructing fingertip amputations, especially in scenarios where preservation of digit length, sensation, and cosmetic outcome is desired.⁴ Various flap reconstruction techniques, such as the V-Y advancement flap, cross-finger flap, homodigital island flap, heterodigital island flap, and thenar flap, have been described for reconstruction of fingertip defects, depending on the digit, size of raw area, and vascularity.⁵

Among the flap options, the volar advancement flap described by Moberg⁶ have demonstrated excellent outcomes in preserving both sensation and length in thumb tip injuries while minimizing complications.⁷ Baumeister et al⁸ demonstrated excellent functional outcome with no flap loss and 74% of patients showing normal sensitivity at 27 months. Mutaf et al⁹ also showed near-normal sensibility compared with contralateral side with static two-point discrimination and Semmes-Weinstein monofilament testing. However, most of the literature focused on results in the thumb, and the use of volar advancement flap in the lesser digits was rarely reported since the original description. Some even considered it as a contraindication due to the absence of a separate dorsal arterial supply system in the lesser digits, unlike the thumb, with the risk of dorsal skin necrosis and flexion contracture in the digits.¹⁰ Hence, our study aims at evaluating the clinical outcome of volar advancement flap with a modified technique for fingertip amputations in lesser digits to demonstrate its feasibility in fingertip reconstruction.

Methods

Surgical Technique

Local anesthesia with 1% lignocaine was administered to the operated digit in digital block fashion with the use of tourniquet. The fingertip wound was débrided and irrigated with normal saline. Bilateral midaxial lines were incised from the wound edge until the distal two-third of the middle phalanx. The volar skin flap was elevated with scalpel using sharp dissection while preserving the flexor tendon sheath (Figure 1). Skeletonizing the digital neurovascular bundles was not required, as the digital neurovascular bundles were well contained within the volar skin flap and iatrogenic injury could be avoided. The skin flap was then advanced to cover the fingertip defect, where suturing was performed using 5/0 nylon sutures with one corrugated drain placed (Figure 2). The corrugated rubber drain was trimmed from the corrugated rubber sheet into a 4 to 5 French gauge size and placed between the distal phalanx bone and the volar skin flap, which was usually left in situ for several days before it was removed. The patient was then started on gentle active mobilization afterwards without splinting or immobilization. Stitches are typically kept for 14 days before removal.

Figure 1.

Image showingelevation of volar skin flap over flexor tendon sheath, with bilateral midaxial incisions, which stop at distal two-third of the middle phalanx.

Figure 2.

A, Image of fingertip amputation of transverse pattern showing a resultant raw area in the index finger. B, Volar view showing the fingertip after volar advancement flap coverage, with corrugated drain in situ. C, Dorsal view showing the fingertip after volar advancement flap coverage.

Study Design

A retrospective cohort study was conducted on patients who underwent modified volar advancement flap reconstruction for fingertip amputation in lesser digits between 2015 and 2021 in a single university center. Exclusion criteria included patients who received volar advancement flap for thumb injuries, nontraumatic causes (eg, infection, gangrene, vasculitis), combination of other local flap reconstruction other than pure volar advancement flap (eg, those with rotational component/V-Y advancement), and those who defaulted on postoperative rehabilitation and follow-up. Patient charts were reviewed for background demographics and injury details. Primary outcome measures included incidence of complications (eg, infection, hook nail deformity, flap necrosis and fixed flexion deformity), objective sensory assessment with monofilament test, and range of motion in the distal interphalangeal joint (DIPJ). Secondary outcome measures included functional assessment with QuickDASH score, power grip strength, and pinch grip strength measurement.

Patient data were anonymously entered into an encrypted file to ensure privacy. Statistical analysis was done with SPSS version 28 (IBM). Standard descriptive statistics were used for baseline parameters, with outcome analysis and comparison using chi-square test, Fisher exact test, independent samples Student t-test with two-tail significance, one-way analysis of variance, and Spearman correlation test as appropriate. A P -value of less than 0.05 was considered statistically significant.

This study was approved by the institutional review board. The need for written patient consent was waived due to the nature of retrospective chart review.

Results

Eighteen patients met the inclusion criteria for analysis, with a mean follow-up duration of 6 months. Background parameters were presented in Table 1. The mean age was 50.9 ± 13.3 years (range 22 to 74 years). Common complications included hypersensitivity (61.1%), infection (11.1%), and wound dehiscence (11.1%) (Table 2). One patient had both infection and wound dehiscence (as a result of the infection), leading to an overall wound healing–related complication rate of 16.7% (3 out of 18). No flap necrosis or failure, either partial or complete, was noted. In addition, no dorsal skin necrosis was found in all cases.

Table 1.

Background Parameters

	n (%)
Sex
Male	12 (66.7)
Female	6 (33.3)
Drinker
Yes	7 (38.9)
No	11 (61.1)
Smoker
Yes	9 (50)
No	9 (50)
Diabetes mellitus
Yes	1 (5.6)
No	17 (94.4)
Injured hand
Left	15 (60)
Right	10 (40)
Injured digit
Index finger	7 (38.9)
Middle finger	5 (27.8)
Ring finger	5 (27.8)
Little finger	1 (5.6)
Injury on duty
Yes	13 (72.2)
No	5 (27.8)
Allen classification
Type 1	0 (0)
Type 2	8 (44.9)
Type 3	6 (33.3)
Type 4	4 (22.2)
Contamination
Mild	11 (61.1)
Gross	7 (38.9)
Nail bed loss
None	1 (5.6)
Partial	13 (72.2)
Complete	4 (22.2)
Nail plate loss
None	1 (5.6)
Partial	7 (38.9)
Complete	10 (55.6)

Table 2.

Complication Profile

Complication	n	%
Hypersensitivity	11	61.1
Infection	2	11.1
Wound dehiscence	2	11.1
Hook nail deformity	1	5.6
Stitch granuloma	1	5.6
Stump bony impingement	1	5.6
Residual nail impingement	1	5.6

Seventy-five percent of patients achieved protective sensation (Semmes-Weinstein Monofilament ≤4.31, Medical Research Council Sensory grade S2 or above), whereas 43.8% reached normal sensation (Semmes-Weinstein Monofilament ≤3.61, Medical Research Council Sensory S3 + or above, static two-point discrimination <5 mm). The median Semmes-Weinstein Monofilament test achieved was 3.61 (range 2.83 to 4.31). Mean flexion/extension range of motion arc was 45.1° ± 14.1° (range 10° to 65°), with fixed flexion deformity of DIPJ seen in 7.1% of patients. The other outcome measures were outlined in Table 3.

Table 3.

Outcome Parameters

Factors	Mean ± SD (Range)
Range of motion
DIPJ extension	0.9° ± 3.2° (0°–12°)
DIPJ flexion	46.0° ± 14.0° (10°–65°)
DIPJ motion arc (flexion-extension)	45.1° ± 14.1° (10°–65°)
Functional outcome
Power grip (compared with contralateral hand)	79.3% ± 19.4% (46%–103%)
Pinch grip (compared with contralateral hand)	64.9% ± 17.7% (33%–95%)
QuickDASH	4.22 ± 5.97 (0–18.18)

DIPJ = distal interphalangeal joint

Otherwise, no statistically significant association was identified between the background parameters and unfavorable outcomes, including incidence of complications, suboptimal sensation, range of motion, or QuickDASH scores.

Discussion

Anatomically, the proper dorsal digital arteries are more developed in the thumb, with two branches from the dorsal metacarpal artery. However, the proper dorsal digital arteries in the lesser digits are often smaller in caliber and do not reach the distal phalanx.¹¹ Therefore, the circulation of the dorsal skin of the distal phalanx relies on the dorsal perforating vessels of the proper volar digital arteries,¹ which usually branch off just proximal to the midpoint of the middle phalanx and cross the midaxial line there. Hence, volar advancement flap was often considered to be contraindicated in the lesser digits by many surgeons, as no dedicated dorsal vascular supply was found.¹⁰ If the dorsal perforating vessels supplying the dorsal skin of the distal phalanx were compromised with extensive midaxial line dissection, there would be risk of dorsal skin necrosis. This is an important anatomical consideration to recognize, but rather than making this a contraindication, we used this point to modify the original technique of volar advancement flap.

Macht and Watson¹¹ first reported their series of 69 digits with volar advancement flap performed in lesser digits, with no dorsal tip necrosis or flap loss. They did report two patients with blistering of the dorsal skin, which healed spontaneously. Outcome was otherwise excellent with almost normal two-point discrimination and less than 5° of extension lag noted in all digits. In their technique, bilateral midaxial lines were incised all the way down to the base of the proximal phalanx. However, they stressed the use of spreading-dissecting technique to preserve perforator vessels, by separating just enough for distal advancement without completely detaching the volar skin flap. Similarly, Murata et al¹² reported the use of volar advancement flap in five lesser digits, together with V-Y closure at the base of proximal phalanx after incising along the midaxial lines toward proximal phalanx, while isolating and preserving the dorsal perforators at the base of the finger and the proximal interphalangeal joint. They also reported no flap loss but showed 60% of claw-nail deformity and cold intolerance of the finger dorsum during winter in their cohort. The other outcome parameters were grouped together with use in the thumb and were therefore not clear whether they were specific to lesser digits. Kojima et al¹³ also reported the use of similar volar advancement techniques with V-Y closure at the base of proximal phalanx, with elongation of 10 to 16 mm obtained in their cohort of 14 digits. The authors stressed the importance of preserving at least two dorsal communicating perforators to avoid dorsal skin necrosis, where microsurgical dissection is required to safely perform such flap. No other literature was found describing the use of it in the past 25 years to our knowledge otherwise.

With our modified technique, there are several points to note when performing volar advancement flap in lesser digits. First of all, when elevating the flap from flexor tendon sheath, it is important that the bilateral midaxial incisions do not go past the midpoint of the middle phalanx, where the dorsal communicating branch of the digital artery to the dorsal surface of the distal phalanx is. This avoids inadvertent damage of the dorsal perforator vessels and also circumvents the need for meticulous microsurgical dissection to preserve these perforators. However, this also limits the advancement power of the flap. Transverse and dorsal oblique amputations are therefore more feasible for volar advancement using this modified technique, whereas volar oblique amputations are poor candidates. To achieve primary skin closure with volar advancement, the DIPJ might need to be flexed slightly to reduce the tension. After the wound heals, postoperative hand therapy would improve the extension lag in DIPJ with progressive mobilization and stretching exercise. Macht and Watson used finger extension splint to relieve flexion deformity,¹¹ but this was not routinely used in our practice. Our results demonstrated a possibility of residual fixed flexion deformity in the DIPJ with the use of volar advancement, but such proportion was low. Finally, a technical tip on achieving a better flap contour is to trim the distal radial and ulnar skin corners of the elevated flap, rounding them off to better match the overall curved shape of the fingertip. Good cosmetic outcome (Figure 3) and functional outcome (Figure 4) could be achieved with our modified technique after rehabilitation.

Figure 3.

Image showing cosmetic appearance after volar advancement flap coverage in the index finger.

Figure 4.

Image showing functional outcome after volar advancement flap coverage in the index finger, with satisfactory extension and flexion range.

Within the complication profile, we observed a high incidence of hypersensitivity in the fingertip. Hypersensitivity is a commonly reported complication following fingertip injuries and is considered a result of the injury itself rather than a complication of the treatment.¹⁴ The reported rate was approximately 50% regardless of treatment modalities, similar to our series. We did not rate the symptomatic severity of this complaint, but all patients reporting hypersensitivity underwent desensitization therapy and sensory re-education with the hand therapists.

When compared with the Atasoy or Kutler V-Y advancement flaps, which share similar surgical indications, this modified volar advancement flap offers two key advantages. First, the surgical dissection follows a well-defined tissue plane superficial to the flexor tendon sheath, allowing the volar skin flap to be easily elevated using a scalpel after Cleland ligament is incised through the midaxial incisions. This contrasts with the V-Y plasty, where the surgeon must carefully divide the fibrous septa using blunt dissection to avoid damaging the delicate vascular supply. Superficial skin necrosis has been reported in the original series by Atasoy et al,¹⁵ or in cases where excessive skin tension causes vascular compromise.¹⁶ However, with this technique, the entire neurovascular bundles remain protected within the volar skin flap during elevation, making vascular compromise to the fingertip unlikely. In addition, the incisions for both the Atasoy and Kutler V-Y advancement flaps cross the center of the pulp, placing the resulting scar in the contact area used for pinching and fine touch. By contrast, the incisions for this modified volar advancement flap spare the pulp center, which may explain the high percentage of satisfactory fingertip sensation observed in our cohort.

The limitations of this study include the small sample size of the cohort. Many patients, especially those in the workforce, tended to default from therapy during the early postoperative period and were therefore excluded from the study. Furthermore, because of the retrospective nature of the review, some documentation was incomplete. Prospective collection of outcome data using a validated fingertip injury outcome score as reported by Jerome et al¹⁷ would also improve the level of evidence in the future. Although this study did not include a comparison with other types of local flap, its primary goal was to demonstrate the feasibility and safety of this modified technique for use in lesser digits, rather than to establish its superiority or inferiority over other options. After all, the choice of reconstructive technique requires a comprehensive assessment of both patient- and injury-specific factors.

Conclusion

The volar advancement flap remains a feasible option for surgical reconstruction in selected cases of fingertip amputation, even in lesser digits. A large proportion of patients achieved protective sensation following volar advancement flap reconstruction, as the neurovascular bundles were advanced within the skin flap without disruption. This modified technique of volar advancement flap does not require microsurgical expertise and can be safely performed by general orthopaedic surgeons.