Finger pulp reconstruction with thenar flap: Aesthetic and functional outcome

Abstract

Purpose

Fingertip injuries are common in industrial production activities as well as in domestic work. Loss of pulp hampers daily life activities. Functional and aesthetic aspects are important in fingertip reconstruction. The bone is usually exposed along with soft tissue loss. Therefore to reconstruct the pulp flap with adequate bulk is required.

Methods

We reported a case series of 12 patients with the injury over the volar aspect of distal phalanx of the index or middle finger. In all cases, laterally based thenar flap was chosen. The flap donor site was closed primarily in most of cases, while 4 patients required skin graft. The flap was detached between 2–3 weeks. Functional assessment was done using static and dynamic 2-point discrimination and range of motion at each joint. The aesthetic outcome was assessed through questionnaire. The results were analyzed using the unpaired t-test (SPSS version 21).

Results

Partial necrosis occurred in 2 cases while rest of flaps survived successfully. Static 2-point discrimination ranged from 6–10 mm, mean 8.6 mm; and dynamic 2-point discrimination ranged from 8–10 mm, mean 8.9 mm. The mean satisfaction score was (4.0 ± 0.55).

Conclusion

Thenar flap is a good choice for reconstruction of the finger pulp as it provides the bulk with good functional and aesthetic outcome.

Introduction

Fingertip injuries are highly predominant in industrial production activities as well as in domestic work. A fingertip can be divided into pulp, nail and the distal phalanx. Patients who lost a significant amount of pulp tissue face trouble in their daily life, such as pinching, picking up small objects, buttoning and unbuttoning their shirts, the “pill-rolling” movements of the fingers and thumb, etc. In short, the dexterity is lost while performing the skilled tasks. The bone is often exposed in these cases, because a bulk of pulp defected.

Multiple flaps have been described in the literature for fingertip reconstruction. Choosing a suitable flap counts upon various factors which including size, shape, location and availability of the flaps. Cross-finger flaps, thenar flaps, reverse metacarpalartery flaps and homodigital flaps are the most frequently used local flaps for reconstruction of the pulp.^1,2,3 The advanced microsurgical technique–toe pulp transfer is another alternative, although it has a steep learning curve, requires supermicrosurgical skills and equipment.

Finger pulp reconstruction with cross-finger flap is commonly performed; however it has certain disadvantages, such as conspicuous donor site at the dorsum of finger along with stiffness of interphalangeal joints (IPJs). Furthermore, cross-finger flaps do not provide adequate bulk and are practically not enough for a multi-finger injury.

Thenar flap was first described by Gatewood⁴ in 1926, and was supported by Meals et al.⁵ It provided adequate glabrous and durable soft tissue to restore pulp. A few limitations on this flap have been described in the literature, such as unsightly donor scars and flexion contracture of IPJ. In a study of 150 patients, Melone et al⁶ described that modified thenar flap based laterally have shown excellent results. In 2006, Rinker⁷ published a study of 19 patients that he used the lateral thenar flap for fingertip reconstruction and reported good functional and aesthetic recovery with minimal complications.

The present study was carried out to assess functional and aesthetic outcome of thenar flap, used for finger pulp reconstruction.

Methods

Patients with fingertip injuries involving index or middle finger were included in this prospective study irrespective of age and sex. Local flaps could not be used because of the volar oblique amputations with soft tissue loss at the pulp. The fingertip injuries involving the ring and little finger were excluded from the study. The patients with injuries over the thenar eminence, pre-existing joint injury, arthritis, joint stiffness and Dupuytren's contracture were also excluded from the study. The results were analyzed using the unpaired t-test (SSPS version 21).

Totally 12 fingertips were reconstructed with laterally based thenar flap (Table 1). All the patients in our study were males. The age of the patients ranged from 20–54 years (mean 35 years). Among them, 6 patients were older than 30 years. Most injuries were occurred at their workplace and the hospital reaching time varied from 2 h to 10 days.

Table 1.

The demographic analysis of the 12 cases in this study.

Serial No.	Age (years)	Interval from injury to admission	Affected finger	Defect	Timing of detachment (days)	Flap uptake	Donor closure	2-PD		ROM (degrees)
								Static	Dynamic	Metacarpophalangeal joint	Proximal interphalangeal joint	Distal interphalangeal joint
1	26	3 h	Right index	Distal phalanx (volar/dorsum)	17	Partial necrosis	SSG	6	4	100	90	45
2	54	2 days	Left middle	Ulnar aspect of distal phalanx	21	Good	Primary closure	4	3	95	95	55
3	35	3 days	Left index	Distal half of pulp	15	Good	Primary closure	4	3	105	90	50
4	30	7 h	Right middle	Distal 1/3 of pulp	18	Good	Primary closure	8	5	100	95	55
5	46	3 h	Left index	Volar aspect of distal phalanx	14	Partial necrosis	SSG	10	8	110	100	55
6	42	6 h	Left middle	Distal half of pulp	19	Good	Primary closure	4	3	90	90	50
7	32	10 days	Right index	Distal and radial aspect of pulp	17	Good	Primary closure	8	6	105	95	50
8	27	12 h	Left index	Distal half of pulp	18	Good	SSG	5	4	100	90	45
9	42	5 days	Right index	Distal half of pulp	16	Good	Primary closure	7	4	95	90	55
10	35	6 h	Right index	Distal 1/3 of pulp	19	Good	Primary closure	4	2	105	95	50
11	20	2 h	Left middle	Ulnar and distal 1/3 volar	18	Good	Primary closure	10	7	90	90	50
12	37	4 h	Right middle	Distal 1/3 of pulp	15	Good	SSG	6	4	100	90	45

SSG: Split skin graft, 2-PD: 2-point discrimination, ROM: Range of motion.

Operative procedure

The procedure was performed under regional anaesthesia. Laterally based thenar flap was raised using the standard technique. The defect was created after proper debridement (Fig. 1A). While designing the flap, the lateral margin of the flap was placed along the metacarpophalangeal (MCP) crease of the thumb to avoid the palm. The width of the flap was kept 1.5 times to the width of the defect to reconstitute the contour.⁶ The base of the flap located at the junction of dorsal and volar skin, the thumb was kept in the palmar-abducted position so that the injured finger was fully flexed at the metacarpophalangeal joint (MCPJ) which brought to the thenar eminence (Fig. 1B).

Fig. 1.

(A) Preoperative status of middle fingertip injury; (B) Postoperative status with laterally based thenar flap; (C) At 1 year follow-up showing healed donor site; (D) After 1 year follow-up middle finger tip showed good contouring.

The flap was raised at the fascia level with utmost care to protect the motor branch of the median nerve. The donor site was closed primarily or skin grafted. The two-thirds of the flap was insetted. The extension blocking splint was given on the dorsum of the hand to keep the hand immobilized for 2–3 weeks.

The flap was detached under local anaesthesia between 2–3 weeks. All the patients underwent physiotherapy in the supervision of the occupational therapist. The patients were then kept in a one year follow-up (Figs. 1C, 1D).

Assessment parameters

Patients were assessed for functional and aesthetic outcome. The functional assessment included static and dynamic 2-point discrimination (2-PD) along with the active range of motion at the MCPJ and IPJ.

Patients were given a questionnaire concerning their post reconstructive aesthetic appearance and were asked about their appearance satisfaction on 4-point Likert scale which ranged from very unsatisfied to very satisfied. Above parameters were assessed at 3, 6, 9 and 12 months. Data analysis was conducted by using the unpaired t-test.

Results

The time of flap detachment extended from 14 to 21 days (mean 17.25 days). Partial necrosis of the flap occurred in 2 patients which were managed conservatively. Flexion contracture of proximal interphalangeal joint (PIPJ) occurred in 2 patients in which 1 was older than 30 years.

The static 2-PD varied from 4–10 mm with mean (6.33 ± 2.21) mm, at the end of one year while dynamic 2-PD was ranged from 2–8 mm with mean (4.41 ± 1.70) mm. The mean range of motion of MCPJ was (99.58 ± 5.93) degrees (ranged, 90–110 degrees). The range of motion for PIPJ was 90–100 degrees with a mean of (92.54 ± 3.22) degrees. The distal interphalangeal joint (DIPJ) motion ranged 45–55 degrees with a mean of (50.41 ± 3.79) degrees.

Questionnaires were answered by all the patients on 4-point Likert scale. Mean satisfaction score was (4.0 ± 0.55). Ninety percent of the patients were satisfied or very satisfied with their reconstruction.

Discussion

Thenar flap was first described by Gatewood⁴ and Meals &Brody.⁵ who have long been criticized for complications related to donor site and the flexion contracture in a reconstructed finger. Classically the flap was raised medially which had encroached on the palm. Later, Flatt⁸ modified classical thenar flap harvesting technique by basing it proximally. Both proximally or medially based thenar flaps were associated with severe donor site morbidity because of the involvement of the palmar skin.

It has been 40 years since the thenar flap was described by Gatewood⁴ when Melone et al.⁶ reported laterally based thenar flap in a case series of 150 patients. The distal border was placed at the MCP crease of the thumb which yield excellent results and avoided donor site morbidity by precluding palmar region. Most of the patients in this series had no significant impairment of function and disfigurement at the donor site.

The functional outcome of flap after detachment was assessed by static 2-PD and dynamic 2-PD along with the range of motion at each joints of the operated finger. Dellon⁹ reported static and dynamic 2-PD as 5.6 mm and 3.3 mm respectively in a series of 5 patients. The p values of above-mentioned results were 0.758 and 0.427, respectively. Similarly, a study of Barbato et al.¹⁰ reported statics 2-PD was 6.5 mm in their series of 20 patients. Results in this study were comparable to both the above studies.

The static 2-PD in our patients ranged 4–10 mm with mean (6.33 ± 2.21) mm while dynamic2-PD had ranged 2–8 mm with mean (4.41 ± 1.70) mm, which is comparable with a report by Dellon⁹ in a series of 5 patients where static 2-PD was 5.6 mm and dynamic 2-PD was 3.3 mm. Similarly, in a study of Barbato et al¹⁰ reported static 2-PD was 6.5 mm in their series of 20 patients.

The mean range of motion at the 3 types of joint were assessed for one year and patient was asked to visit regularly at an interval of 2 weeks in which emphasis was given on the physiotherapy at each joint. In our case series of 12 patients, 2 patients have lost follow-up. Joint stiffness after thenar flap has been debated. Range of motion achieved in this study at MCPJ, PIPJ and DIPJ is similar to study by Rinker et al.⁷ At the end of one year, the range of motion at the MCPJ was (99.58 ± 5.93) degrees varying between 90–110 degrees. The range of motion for PIPJ was between 90–100 degrees with a mean of (92.54 ± 3.22) degrees. The DIPJ motion ranged between 45–55 degrees with a mean of (50.41 ± 3.79) degrees. The range of motion has always been improved with the time and in the studies where the patient followed up for 2 years showed the improved range of motion.⁷ The mean MCPJ motion in the reconstructed finger was (99.58 ± 5.93) degrees, mean PIPJ motion was (89 ± 3.6) degrees and mean DIPJ motion which was 42 degrees. Though p value showed no significant difference in our study in comparison with previous study, nonetheless our duration was lesser than his studies.⁷

Cautions has been advised about the operative procedure of fingertip injury under taken in patients older than 30 years of age due to post operative flexion contracture deformity in these patients.¹¹ However, in this series we found no significant difference in functional and aesthetic outcome in different age groups. Two patients developed flexion contracture in reconstructed finger were managed conservatively. Out of them, one was 26 years old and the other was 42 years old. The flexion contracture could be easily avoided in a well motivated patient with strict active and passive physiotherapy schedule.

As suggested by Gatewood⁴ the flap was detached in 14–21 days. There was only one case who was 42 years old where detachment was done after 21 days because patient could not come earlier for the detachment.

Fingertip reconstruction by thenar flap follows the basic principle of plastic surgery, replacing like with like. It provides durable glabrous skin with sufficient bulk to fingertip. And if properly designed, donor related complications can be avoided. Other flap that can provide like to like replacement is toe to finger pulp transfer without the complication of flexion contracture as joints are not fixed in one position. However, it requires super microsurgical skills and equipment which is not available at every institute. Limitations of this study are small sample size and lack of comparison with other flaps and normal contralateral finger.

Thenar flap is a good choice for reconstruction of the finger pulp as it provides the bulk and colour match. Active physio therapy post-operatively reduces the risk of PIP contracture.

Funding

Nil.

Ethical Statement

The study approved by an ethical committee with an approve No:AIIMS/IEC/2019/834.

Declaration of Competing Interest

The authors declare no conflicts of interest.