Clinical Outcomes and Complications of Primary Fingertip Reconstruction Using a Reverse Homodigital Island Flap: A Systematic Review

Abstract

Background

Reverse homodigital island flaps (RHIFs) are increasingly used to reconstruct traumatic fingertip injuries, but there is limited evidence on the efficacy of this technique. We performed a systematic review of the literature to establish the safety and functional outcomes of RHIF for traumatic fingertip injuries.

Methods

Electronic searches were performed using 3 databases (PubMed, Ovid Medline, Cochrane CENTRAL) from their date of inception to April 2020. Relevant studies were required to report on complications and functional outcomes for patients undergoing RHIF for primary fingertip reconstruction. Data were extracted from included studies and analyzed.

Results

Sixteen studies were included, which produced a total cohort of 459 patients with 495 fingertip injuries. The index and middle fingers were involved most frequently (34.6% and 34.1%, respectively), followed by the ring finger (22%), the little finger (6.7%), and the thumb (2.6%). The mean postoperative static and moving 2-point discrimination was 7.2 and 6.7 mm, respectively. The mean time to return to work was 8.4 weeks. The mean survivorship was 98.4%, with the pooled complication rate being 28%. The pooled complication rate of complete flap necrosis was 3.6%, of partial flap necrosis was 10.3%, of venous congestion was 14.6%, of pain or hypersensitivity was 11.5%, of wound infection was 7.2%, of flexion contractures was 6.3%, and of cold intolerance was 17.7%.

Conclusions

Reverse homodigital island flaps can be performed safely with excellent outcomes. To minimize complications, care is taken during dissection and insetting, with extensive rehabilitation adhered to postoperatively. Prospective studies assessing outcomes of RHIF compared with other reconstruction techniques would be beneficial.

Keywords

flap homodigital reverse-flow finger fracture/dislocation diagnosis trauma microsurgery specialty systematic review

Introduction

Fingertip injuries are common and are often associated with digital pulp loss and exposure of tendon or bone, along with injury to the nail bed complex.^1,2 This constellation of injuries can be challenging for hand surgeons, who must balance function, cosmesis, and sensibility when reconstructing the digit. The reconstructive armamentarium includes local (V-Y advancement or antegrade homodigital neurovascular island flaps), regional (cross-finger, thenar, or reverse homodigital island flaps [RHIPs]), distant (pedicled groin), or free flap options.³

The RHIF is raised from the proximal dorsoradial or dorsoulnar aspect of the injured digit on a distally based pedicle of the digital artery, which has been ligated proximally (Figure 1).^4-6 The abundant distal anastomoses between the digital arteries (namely, the superficial, proximal subungual, and distal subungual arcades) allow for a retrograde arterial supply, whereas venous drainage is achieved through the perivascular cuff of tissue on the pedicle. Furthermore, sensibility can be maintained through inclusion of the dorsal branch of the digital nerve when harvesting, which is then coapted to the remainder of the digital nerve after distal flap inset. An advantage of this technique is that the flap provides a wide arc of motion to allow for more effective soft tissue coverage distally, optimizing the length of the reconstructed digit and preserving function and aesthetic qualities.⁶ An RHIF allows single-stage reconstruction, with a quicker recovery and shorter period of immobilization when compared with other multistage procedures such as cross-finger or reverse cross-finger flaps.^6,7 The flap is also durable and typically has a similar color and thickness to the surrounding area.⁸ Nevertheless, RHIFs can be complicated by postoperative venous congestion, flap necrosis, flexion contractures, and cold intolerance.⁹

The outcomes of the RHIF have not been well explored in the literature to date, with existent studies being of retrospective observational design and limited by small cohort numbers. Thus, the aim of this study was to systematically review the evidence on the functional outcomes and safety of RHIFs as a surgical technique for reconstructing traumatic fingertip injuries.

Methods

Literature Search Strategy

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed for this study. Electronic database searches were performed using PubMed, Ovid Medline, and Cochrane CENTRAL from their dates of inception to April 2020. The sensitivity of the search strategy was maximized by combining the terms “homodigital,” “finger flap,” “island flap,” “reverse-flow,” and “finger reconstruction” as search terms in the title, abstract, keywords, and MeSH fields. The reference list of all retrieved articles was manually reviewed to further identify potentially relevant studies.

Selection Criteria

Studies eligible for this systematic review reported on patients undergoing RHIF for primary fingertip reconstruction. Included studies were required to report on complications and functional outcomes at any follow-up length. If multiple studies reported outcomes from the same cohort, data from the longest follow-up period were included for quantitative analysis. Publications included were limited to those in the English language and involving human subjects. Conference presentations, case reports, reviews, editorials, and expert opinions were excluded.

Data Extraction and Critical Appraisal

All relevant data were extracted from the article text, figures, and tables. Two investigators (J.X. and J.C.) independently reviewed and extracted data from the retrieved articles. Discrepancies between the 2 reviewers were resolved by discussion with senior authors to reach a consensus. Study characteristics extracted included study year, country, and number of digits involved. Primary outcomes assessed included static and moving 2-point discrimination (2-PD), time to return to work, and total range of motion (ROM). Major (full flap necrosis) and minor (partial flap necrosis, venous congestion, flexion contracture, cold intolerance, pain/hypersensitivity, and superficial wound infection) complications were also extracted.

Statistical Analysis

The event rate was extracted as the primary summary statistic for dichotomous outcomes. The random-effects model was used in all cases owing to differences in patient characteristics and procedural factors between studies. Sensitivity analysis using the leave-1-out method was undertaken to assess the robustness of findings. Publication bias was assessed visually by funnel plots and statistically by the Egger test. All statistical analyses were carried out using Comprehensive Meta-Analysis software (version 3.0; Biostat, Inc, Englewood, New Jersey).

Results

Search Results

An initial search of electronic databases led to the identification of 842 references (Figure 2). After duplicate studies were removed, a total of 590 studies remained for screening. A further 515 studies were excluded following abstract screening, leaving 75 studies for full-text analysis. A total of 16 studies were found to be eligible following application of the inclusion crtiera.^{1,2,4-6,8,10-19} Manual searching of references in each of the full-text articles did not yield further studies for inclusion. Fifteen of the studies were retrospective observational studies, with 1 being of prospective cohort design.

Baseline Characteristics

A total cohort of 459 patients with 495 fingertip injuries were extracted from the 16 studies. The index and middle fingers were involved most frequently (34.6% and 34.1%, respectively), followed by the ring finger (22%), the little finger (6.7%), and the thumb (2.6%). The study period ranged from 1986 to 2016, with a mean follow-up of 25.4 months (range: 5.4-71 months). The mean patient age was 34.7 years (range: 21-47.4 years). The mean proportion of women was 20.7% (range: 0%-87.2%). Ten studies reported defect/flap size, which ranged from 1.5 to 8.1 cm². Twelve studies reported on the method of donor site closure, which was direct primary in 23%, split-thickness skin graft in 15%, and full-thickness skin graft in 62% of operations. The study characteristics are summarized in Table 1.

Table 1.

Characteristics and Demographics of Studies Included in the Systematic Review.

Author	Year	Study period	Country	Study type	Female no.	Total patient no.	Total no. of digits	Location of injury					Mean size of defect/flap, cm² (range)	Age, y (SD)	Follow-up, mo (SD)
Author	Year	Study period	Country	Study type	Female no.	Total patient no.	Total no. of digits	Thumb	Index	Middle	Ring	Little	Mean size of defect/flap, cm² (range)	Age, y (SD)	Follow-up, mo (SD)
Acar et al²	2014	2011-2013	Turkey	R, OS	0	11	22	0	4	11	7	0	4.1 (2.6-5.5)	31.1 (6.5)	14 (4.5)
Adani et al¹⁰	1995	1990-1994	Italy	R, OS	2	11	11	0	3	5	3	0	5.8 (4.5-7.5)	37 (11)	—
Alagoz et al¹¹	2006	2000-2003	Japan	R, OS	—	14	14	4	3	2	5	0	—	21 (8.5)	14 (2.9)
Han et al¹²	1998	1984-1995	Japan	R, OS	96	110	120	0	44	33	33	10	(1.5-8)	31.3 (10.3)	5.4
Han et al¹³	2004	1999-2002	Japan	R, OS	—	28	28	—	—	—	—	—	—	—	—
Huang et al¹⁴	2008	1993-2005	Taiwan	R, OS	35	45	45	—	—	—	—	—	(1.5-4)	34.9 (11.4)	71 (30.4)
Kayalar et al¹⁵	2011	1997-2008	Turkey	R, OS	3	60	67	0	24	27	12	4	(1.5-7)	—	39.7 (24.4)
Kojima et al¹⁷	1990	—	Japan	R, OS	0	7	8	0	1	6	1	0	3 (1.5-4)	47 (12)	—
Lai et al¹⁸	1989	1986-1989	Taiwan	R, OS	3	11	11	0	2	8	0	1	(3-8)	31.7 (10.9)	15.2 (2.5)
Momeni et al⁴	2008	2005-2006	Germany	R, OS	0	11	11	—	—	—	—	—	—	47.4 (6.9)	> 6
Niranjan and Armstrong⁵	1994	—	UK	R, OS	5	25	25	5	7	8	1	4	—	—	—
Sapp et al¹⁹	1993	—	USA	R, OS	—	11	13	0	5	2	4	2	—	—	—
Sundaramurthy et al¹	2017	2015-2016	India	R, OS	1	18	18	0	3	11	3	1	4.1 (2.7-7)	—	—
Takeishi et al⁶	2006	—	Japan	R, OS	0	8	8	1	2	4	0	1	4.1 (1.5-6.6)	37.3 (5.9)	10 (4.7)
Yazar et al¹⁶	2010	2006-2008	Turkey	R, OS	10	66	70	0	36	15	16	3	—	31.5 (9.3)	> 6
Yildirim et al⁸	2002	1998-2000	Turkey	P, OS	3	23	24	—	—	—	—	—	(1.7-8.1)	33 (4.4)	—

Note. R = Retrospective; OS = Observational study; P = Prospective.

Clinical Outcomes

The pooled mean of static 2-PD was 7.2 mm (95% confidence interval [CI], 6.2-8.1 mm, I² = 98.8, P < .001). Static 2-PD was reported in 9 studies and ranged from 4 to 12 mm. The pooled mean of moving 2-PD was 6.7 mm (95% CI, 3.7-9.8 mm, I² = 98.7, P < .001). Moving 2-PD was reported in 3 studies and ranged from 3.5 to 11 mm. The pooled total ROM was 254.3° (95% CI, 250.8°-257.8°, I² = 0, P = .48) and was only reported in 2 studies. The mean time to return to work was 7.2 weeks and ranged from 4.5 to 8.4 weeks.

Complications

Survivorship was reported in all studies, with a pooled rate of 98.4%. From patients requiring reoperation, 88% were due to morbidity at the recipient site and 12% were due to donor site morbidity. The pooled rate of total complications was 28% (95% CI, 18.4%-39.9%, I² = 78.7, P < .001) (Figure 3). From the studies reporting on complete flap necrosis, the pooled rate was 3.6% (95% CI, 1.0%-12.2%, I² = 49.9, P = .11). For minor complications, the pooled rate of partial flap necrosis was 10.3% (95% CI, 6.1%-16.9%, I² = 41.1, P = .08), of venous congestion was 14.6% (95% CI, 10.5%-19.9%, I² = 2.3, P = .42), of pain or hypersensitivity was 11.5% (95% CI, 4.4%-26.8%, I² = 73.7, P < .01), of wound infection was 7.2% (95% CI, 1.4%-30.1%, I² = 69.3, P = .038), of flexion contractures was 6.3% (95% CI, 2.4%-15.3%, I² = 43.3, P = .15), and of cold intolerance was 17.7% (95% CI, 9.8%-29.7%, I² = 71.7, P = .01). These pooled complication rates are represented by the forest plot (Figure 4). The complication rates for each individual study are summarized in Table 2.

Table 2.

Survivorship and Complication Rates Reported by Each Study Included in the Systematic Review.

Author	Year	Survivorship, %	Total complications, No. (%)	Complete flap necrosis, No. (%)	Partial flap necrosis, No. (%)	Venous congestion, No. (%)	Pain or hypersensitivity, No. (%)	Wound infection, No. (%)	Flexion contracture, No. (%)	Cold intolerance, No. (%)
Lai et al¹⁸	1989	100	2 (18.2)			2 (18.2)
Kojima et al¹⁷	1990	100	3 (37.5)		1 (12.5)	2 (25)
Sapp et al¹⁹	1993	100	1 (7.7)				1 (7.7)
Niranjan and Armstrong⁵	1994	96	21 (84)		7 (28)			5 (20)		9 (36)
Adani et al¹⁰	1995	100	3 (27.3)			2 (18.2)	1 (9.1)		2 (18.2)	3 (13.6)
Han et al¹²	1998	99.2	21 (17.5)	1 (0.8)		20 (16.7)
Yildirim et al⁸	2002	91.7	15 (62.6)	2 (8.3)	3 (12.5)	8 (33.3)	10 (41.7)			10 (41.7)
Han et al¹³	2004	100	0 (0)
Alagoz et al¹¹	2006	100	3 (21.4)		1 (7.1)	1 (7.1)		1 (7.1)		1 (7.1)
Takeishi et al⁶	2006	87.5	4 (50)	1 (12.5)	1 (12.5)	2 (25)
Huang et al¹⁴	2008	100	22 (48.9)		3 (6.7)		3 (6.7)			8 (17.8)
Momeni et al⁴	2008	90.9	1 (9.1)		1 (9.1)	1 (9.1)
Yazar et al¹⁶	2010	100	15 (21.4)		1 (1.4)		4 (5.7)		3 (4.3)	7 (10)
Kayalar et al¹⁵	2011	98.5	9 (13.4)	1 (1.5)	4 (6)	1 (1.4)		1 (1.5)	1 (1.5)	1 (1.5)
Acar et al²	2014	95.5	5 (22.7)		1 (4.5)	2 (9.1)			2 (9.1)	6 (27.3)
Sundaramurthy et al¹	2017	100	4 (22.2)		4 (22.2)		2 (11.1)			0 (0)

Quality of Studies

Leave-1-out sensitivity analysis yielded no major changes to the pooled effect sizes. Publication bias according to the Egger test was not significant for any outcomes, except cold intolerance (P = .01), as seen by symmetrical funnel plots. Heterogeneity was measured using Cochran’s Q and I² statistic. Significant heterogeneity was not noted in any outcome except total complications (P < .001), pain or hypersensitivity (P = .002), and cold intolerance (P = .001)

Discussion

This study reviews the literature regarding RHIF and finds a pooled flap survivorship of 98.4%. Clinically, the mean static 2-PD was 7.2 mm, with a digital ROM of 254° at final follow-up. The total pooled complication rate was 28%, with the most common complication being cold intolerance (noted in 17.7% of patients). The high survivorship, acceptable functional recovery, and low major complication rate mark the RHIF as an attractive option in the management of traumatic fingertip injuries.

Optimal reconstruction of fingertip injuries should provide sufficient soft tissue coverage and restore sensation, ROM, and digital length.²⁰ Various flap techniques have been used for reconstructing traumatic fingertip injuries. Injuries with small defects of a volar oblique configuration may be appropriately managed via local V-Y or antegrade homodigital neurovascular island flaps to provide excellent coverage. However, larger defects may require regional or distant flaps or the consideration of replantation. While replantation is a highly effective surgical option, it is technically difficult at this level and often not possible.²¹ Cross-finger flaps are commonly used for larger defects, but necessitate prolonged immobilization, often resulting in stiffness. Other locoregional options (such as the arterialised dorsal flap) can be used, but poor outcomes have limited surgical uptake.¹¹ Thus, the RHIF has become increasingly used.

The advantages of the RHIF include its single-stage implementation (as opposed to multistage regional flaps), resulting in shorter hospital stays, an earlier return to work, and diminished associated costs.¹⁶ A single-stage procedure also allows earlier active motion, which is particularly advantageous in the setting of an acute traumatic injury. The RHIF provides reliable retrograde flow from the closest performant arteries, whereas the long vascular pedicles allow a wide arc of transposition to provide sufficient tissue for distal reconstruction.^15,16 The skin on the dorsolateral aspect of the proximal phalanx is thick and hairless, making it an ideal donor for the volar pulp.¹⁶ Furthermore, as the donor and recipient sites are on the same digit, this operation can be performed using only a regional anesthetic if required.

One of the most common complications reported in the included studies was venous congestion. This is in contrast to direct-flow flaps in which venous insufficiency is quite rare. To minimize venous congestion, care must be taken to maintain a perivascular cuff of tissue around the digital artery, which contains many venules to allow drainage.¹ The current authors also recommend that a mid-lateral incision be used for raising and transposing the flap because this can be left open to minimize compression of the vascular pedicle. The blood supply and perfusion to the flap should be carefully checked before and after insetting, with release of sutures if necessary. Care should also be taken to avoid a tight closure, with a low threshold for using a skin graft on top of the donor site/mid-axial incision if required. If venous congestion were to occur within 24 hours, Kaylar et al¹⁵ demonstrated the success of performing a secondary venous anastomosis. Interestingly, earlier studies appeared to report higher rates of venous congestion, with studies published before 2005 having a mean venous congestion of 23.3%. In more recent studies, the rate of venous congestion has markedly decreased with an average of 10.7% for studies published after 2005. This may be due to the greater understanding of the importance of maintaining a perivascular cuff of tissue, as well as improved physical rehabilitation programs. Venous anastomosis was also not significantly reported in the included studies, with only Kaylar et al¹⁵ reporting its use in one of their patients.

Sensory restoration is another important outcome in fingertip reconstruction. To improve sensibility of an RHIF, the dorsal digital nerve can be harvested and coapted to the remaining digital nerve. Results vary in the literature as to whether nerve coaptation provides improved 2-PD when compared with insensate flaps. Lai¹⁸ reported that the inclusion of the dorsal digital nerve in the RHIF resulted in a 2-PD of 3.5 mm. Similarly, Kaleli et al²² found that 2-PD was improved in patients where nerve coaptation was performed (5-7 mm) when compared with those where this was not attempted (8-10 mm). Earlier studies by Koijma et al¹⁷ and Sapp et al¹⁹ also reported that no nerve coaptation produced a suboptimal 2-PD of approximately 10 mm. However, Han et al¹³ found that the long-term outcomes of sensate and insensate flaps were comparable, with similar 2-PD and subjective patient views. Thus, the additional operative time and greater dissection required for a sensate flap may result in some surgeons opting against coaptation. Further studies would be beneficial in elucidating differences in outcome.

Almost 1 in 20 patients sustained a postoperative flexion contracture. To reduce the chance of developing a contracture, care must be taken with the dissection and insetting of the flap. Small, well-planned incisions with the use of smooth nonabsorbable sutures may minimize scar formation and flexion contractures.⁹ Sundarmurthy et al¹ attributed the absence of flexion contractures in his cohort to the fact that all incisions were made in the mid-axial line, with no flaps raised distal to the proximal interphalangeal joint. Postoperatively, the use of silicone gel sheets, compression garments, and triamcinolone injection can potentially also reduce scar formation and resulting contractures.¹ Meticulous postoperative physical rehabilitation for up to 6 months has also been suggested to reduce the incidence of flexion contractures.¹¹

It is important to consider the limitations of this study. First, there was high heterogeneity in the studies that were included. The included studies did not report the cause of the injury and how severe the injuries were, limiting the ability to standardize the results. The follow-up period of each of the included studies also ranged from 5.4 to 71 months. The technical skills of the surgeons varied across and within studies, which is an important confounder, particularly because an RHIF is a technically challenging procedure. The included studies were all observational in nature and primarily retrospective, limiting the interpretation of cause and effect. Furthermore, many of the included studies had variable and incomplete reporting of outcomes and complications.

Conclusion

The pooled results of this review provided the largest cohort of patients in the literature undergoing RHIFs for the reconstruction of fingertip injuries. This study reveals that this technique can be performed safely with excellent outcomes and survival. To minimize complications, it is essential that care be taken during dissection and insetting, and that extensive rehabilitation is adhered to postoperatively. Prospective studies assessing outcomes of RHIF compared with other reconstruction techniques would be beneficial.

Footnotes

Ethical Approval

This study was approved by our institutional review board.

Statement of Human and Animal Rights

This article does not contain any studies with human or animal subjects

Statement of Informed Consent

No informed consent was required for this study.

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

ORCID iDs

Joshua Xu

David J. Graham

Brahman S. Sivakumar

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