Reconstruction and Outcome of Foot Defects Following Oncological Resection-Experience from a Cancer Centre in North-East India

Abstract

Solid tumours around the foot are rare and include soft tissue sarcomas, skin and bone malignancies. Extended soft tissue defects due to oncological resection result in the loss of shock-absorbing and friction resistant tissue, which leads to altered walking patterns and pain. Replacement of plantar tissue requires soft tissue resistant to weight, pressure and shear stress. The other important desired goal of foot reconstruction is short wound healing time in order to allow adjuvant therapy at stipulated time. This is a retrospective study from March 2016 to October 2019. A total of twenty-one (n = 21) patients were operated for foot malignancies during this period in our institute and the resulting defects were reconstructed using various methods. Different reconstructive surgeries were performed depending on tumour size, location and general health status of patients. The length of hospitalization and the presence of local postoperative complications were assessed. Functional outcomes were measured in terms of MSTS score. Average age of the series is 53.1 years. Sixty-six percent of the patients (n = 14) presented with tumour at the weight bearing areas and 33% patients (n = 7) at the non-weight bearing areas of the foot. Fifty-seven percent of patients (n = 12) presented with malignant melanoma of foot, squamous cell carcinoma was seen in 33% (n = 7) patients and 4% patients (n = 1 each) presented as osteosarcoma and malignant peripheral nerve sheath tumour respectively. The mean MSTS score in patients with weight bearing areas (location) is statistically significant (p = 0.031). There is a significant correlation between the surgical complications and follow up MSTS score (p = 0.046) which signifies that flap related complications result in lower MSTS score. The mean MSTS score was 22.71/30. Complications were observed in three cases which included partial flap necrosis, graft loss and foot stiffness. Simple skin grafts to local flaps maybe a viable option in a limited resource setting based on the location of defect. Free tissue transfer is the ideal choice in case of weight bearing areas to achieve acceptable outcomes.

Introduction

Solid malignancies around the foot are rare and include soft tissue sarcomas, skin and bone malignancies. Anatomically foot can be divided into hindfoot, midfoot and forefoot. The hindfoot consists of talus and calcaneus, mid foot has five bones- the navicular, the cuboid and the three cuneiform bones. The mid foot is responsible for forming the arches of the foot and acts as a shock absorber when walking or running. The forefoot consists of phalanges, and metatarsal bones.

For reconstruction of foot defects, knowledge of the anatomy of foot, the weight bearing interface for ambulation, bone architecture, the longitudinal and transverse arches and the compartments is important. Half of the weight of the body while standing is transferred to the calcaneus and the other half to the five metatarsals. The weight distribution at the forefoot is in the ratio of 2:1:1: 1:1(in relation to metatarsals) with the first metatarsal bearing the burden of most of the load at the forefoot. The heavy plantar ligaments, the plantar aponeurosis and the short plantar muscles form the support of the arch. The long muscles of the leg position the foot via effective muscle contraction and helps to effectively bear weight and also afford some protection [1].

Extended soft tissue defects due to oncological resection, result in the loss of shock-absorbing and friction resistant tissue, which leads to altered walking patterns and pain [2]. Therapeutic options, which ensure complete resection of the tumour, while maintaining the biomechanical function of the foot and ankle, are necessary. Replacement of plantar tissue requires soft tissue resistant to weight, pressure and shear stress [2]. The foot reconstruction must be durable enough to withstand the weight of the body. The other important desired goal of foot reconstruction is short wound healing time in order to allow adjuvant therapy at stipulated time [3]. Various surgical procedures, such as skin graft, local, regional and free flaps, have been described as options for foot reconstruction.

Available literature on factors affecting outcome of reconstruction of foot defects is limited and needs exploration. This study is aimed at evaluating and comparing the factors that affect the functional outcome of foot reconstruction.

Materials and Methods

This is a retrospective study carried out in the Surgical Oncology Department, Dr B. Borooah Cancer Institute, Guwahati, from March 2016 to October 2019. Different reconstructive surgeries were performed depending on tumour size, location and general health status of patients. The length of hospitalization and the presence of local postoperative complications were assessed. Functional outcomes were measured in terms of MSTS score. All the patients were followed up for a minimum period of 12 months (Fig. 1).

Fig. 1.

Bar graphs showing clinical factors affecting functional outcome

A total of twenty-one (n = 21) patients were operated for foot malignancies during this period and all the defects were reconstructed using various methods. Out of the twenty-one patients, eleven (n = 11) were male and ten (n = 10) were female. Defect size was classified as small (< 5 cm) or large (> 5 cm) based on largest dimension.

Age Distribution

Average age of the series is 53.1 years. Most of the patients (n = 11) are between 5 and 6th decade of life. The youngest patient is 29 years old and the oldest being 80 years old.

Type of Primary Tumour

Fifty-seven percent of patients (n = 12) presented with malignant melanoma of foot, squamous cell carcinoma was seen in 33% (n = 7) patients and 4% patients (n = 1 each) presented as osteosarcoma and malignant peripheral nerve sheath tumour respectively. Post-operative resection margins were free in all the patients (Figs. 2, 3, and 4).

Fig. 2.

a Case of melanoma of heel, b defect following resection, c marking and planning of reverse sural flap used for reconstruction of defect, and d, e final reconstructed outcome

Fig. 3.

a Recurrent melanoma involving forefoot; b, c defect following resection and plan for plantar rotation flap used to reconstruct the defect; d, e final outcome following reconstruction

Fig. 4.

a Case of melanoma of forefoot, b planning of free radial forearm flap used for reconstruction, c defect with recipient vessels, d final outcome following flap inset

Location of the Tumour

Sixty-six percent of the patients (n = 14) presented with tumour at the weight bearing areas and 33% patients (n = 7) at the non-weight bearing areas of the foot. As a whole, 52% patients (n = 11) had tumour at the hindfoot, 38% at the midfoot (n = 8) and 9% at the forefoot (n = 2) (Figs. 5 and 6).

Fig. 5.

a Case of osteosarcoma of first metatarsal, b x-ray of foot showing lesion, c dissection of lesion, d planning of free fibular graft; e, f external fixator used for stabilisation of reconstructed bone defect

Fig. 6.

a Case of melanoma of plantar surface of foot, b primary defect following resection, c, d medial plantar artery flap harvest, e skin graft used for donor site defect and flap inset of primary defect done

Hospital Stay

The length of hospital stay varied from 7 to 15 days with mean hospital stay being 9.9 days.

Procedures Performed and Technical Considerations

Resection of tumour in all cases was performed adhering to standard practice of taking adequate margin of 1–2 cm all around the tumour based on histology. Margins to adjacent functional structures like fascia, synovia, periosteum and perivascular and perineural tissue was taken into account. When there was tumour infiltration of such structures, en-block resection was performed. The course of vascular structures was taken into account during the resection to allow planning of reconstructive procedures by using pedicled or free tissue transplantation.

The procedures were performed with a combined effort of surgical oncology and plastic surgery team.

Weight-bearing areas include metatarsals and calcaneum (heel), while rest considered non-weight bearing. [4]

Preoperatively, all patients underwent MRI foot to assess extent of involvement of soft tissue and neurovascular bundle if any. Contraindications to limb salvage were neurovascular bundle involvement, pathological fracture, extensive soft tissue involvement not amenable to reconstruction.

Alternative procedure performed was below knee amputation if limb salvage found to be not feasible.

Reconstruction of defect was performed using various techniques including split skin grafting, reverse sural artery flap, medial plantar artery flap, free radial forearm flap and free fibular flap. Out of the twenty-one patients, in fourteen cases, reconstruction was done using various flaps, and in the remaining seven cases, skin grafting was used.

The reverse sural artery flap was used in nine cases and in none of the cases tunnelling of the pedicle was done. The skin bridge between the defect and the donor site was incised in order to avoid compression and the pedicle was placed there with skin graft covering the raw pedicle. The donor site was also skin grafted.

The medial plantar artery flap was performed in one case of midfoot defect (weight-bearing area).

One patient with weight bearing right heel defect was reconstructed with flexor digitorum brevis flap. The patient had extensive post traumatic scar marks over the calf area, excluding the option of the reverse sural flap for reconstruction.

Free radial forearm flap was done for a patient with forefoot defect 8 × 9 cm². The flap was raised from non-dominant (left) forearm and placed at the defect. The pedicle was brought to the dorsum of the foot via a tunnel at the medial border of the foot, anastomosis done between radial artery and dorsalis pedis artery, vena comitantes of the pedicle with anterior tibial vein and cephalic vein with the great saphenous vein. Post-operatively, below-knee plaster of paris slab was applied to stabilize the flap and prevent unnecessary movements.

The free fibular osseus flap was used in a case of first metatarsal osteosarcoma of the foot. The tumour was excised in toto and vascular fibula without a skin paddle was harvested (as skin loss was not present in the defect) from the opposite leg and placed in the defect. External fixator was applied to stabilize the bone and vascular anastomosis performed between peroneal artery with the dorsalis pedis artery and vena comitantes of the peroneal pedicle with the great saphenous vein.

Rehabilitation

Weight bearing initiated after wound healing/suture removal at 2-week post-op in non-weight bearing areas and 4 weeks in weight bearing areas. Gradual range of motion increased as per physiotherapy protocol. Non-weight bearing movement was encouraged from 1-week post-op.

During rest, 20° leg elevation was prescribed.

Follow-up

Functional score was assessed with musculoskeletal tumour society scoring system (MSTS). All the patients were advised post-operative rehabilitation in the physiotherapy unit of our hospital. The patients were asked to follow up at the surgical oncology OPD on 2nd week post-surgery and thereafter at the 3rd, 6th month and at the end of 1 year. MSTS score was evaluated at the end of 1 year in all the patients (Figs. 7, 8).

Fig. 7.

Follow-up reverse sural flap postoperative outcome

Fig. 8.

Follow-up medial plantar flap postoperative outcome

Results and Observation

The mean MSTS score in patients with weight bearing areas (location) is statistically significant (p = 0.031). There is significant correlation between the surgical complications and follow up MSTS score (p = 0.046) which signifies that flap related complications result in lower MSTS score. We have evaluated the size of the defect, and categorised the defect into small and large (≤ 5 cm, ˃ 5 cm in largest dimension). It is observed that large wounds have lower mean MSTS score compared to small wounds, which is statistically significant (p = 0.013). The clinicopathological features have been described in Table 1.

Table 1.

Clinico-pathological and demographic characteristics of patients

S no	Age	Sex	Diagnosis	Tumour location	Defect size (cm3)	Surgery	MSTS score	Complications	Recurrence
1	63	F	Melanoma	Left heel weight bearing	7 × 7 × 2	WLE + reverse sural flap	18	Yes	No
2	61	M	Melanoma	Left heel weight bearing	7 × 4 × 1.5	WLE + reverse sural flap	21	No	No
3	55	M	SCC	Left midfoot non weight bearing	3.6 × 2.5 × 1.3	WLE + SSG	25	No	No
4	50	M	SCC	Right heel weight bearing	6 × 3.5 × 2	WLE + reverse sural flap	21	No	No
5	71	F	SCC	Left heel weight bearing	5.5 × 3.2 × 0.9	WLE + reverse sural flap	23	No	No
6	60	M	Melanoma	Right midfoot non weight bearing	2.8 × 2.5 × 1	WLE + SSG	21	No	No
7	40	F	SCC	Right midfoot non weight bearing	3.5 × 3.5 × 1.3	WLE + SSG	23	No	No
8	37	M	Melanoma	Right heel weight bearing	4 × 3 × 1.5	WLE + plantar rotation flap	22	No	Yes
9	54	F	Melanoma	Right midfoot non weight bearing	3.4 × 3 × 1.5	WLE + SSG	24	No	No
10	42	M	SCC	Right heel weight bearing	6.3 × 3.8 × 1	WLE + reverse sural flap	24	No	No
11	50	F	Melanoma	Left heel weight bearing	5.5 × 4 × 1.5	WLE + reverse sural flap	24	No	No
12	60	M	SCC	Right midfoot non weight bearing	2.5 × 3 × 1.2	WLE + SSG	24	Yes	No
13	40	F	Melanoma	Left heel weight bearing	5.3 × 3.1 × 0.5	WLE + reverse sural flap	25	No	No
14	51	F	MPNST	Right heel weight bearing	4.8 × 3.8 × 1.5	WLE + FDB FLAP + SSG	22	No	No
15	80	F	Melanoma	Right heel weight bearing	6.5 × 3.5 × 0.8	WLE + reverse sural flap	22	No	No
16	56	F	Melanoma	Left heel weight bearing	5.2 × 2 × 1	WLE + reverse sural flap	23	No	No
17	55	M	SCC	Left midfoot non weight bearing	2.5 × 2x0.8	WLE + SSG	26	No	No
18	65	M	Melanoma	Right midfoot non weight bearing	1.8 × 1.8 × 1	WLE + SSG	25	No	No
19	42	M	Melanoma	Right forefoot weight bearing	8 × 9	WLE + free radial forearm flap	24	No	No
20	55	M	Melanoma	Right midfoot weight bearing	4.6 × 3.8 × 1.6	WLE + medial plantar flap + SSG	21	No	No
21	29	F	Osteosarcoma	Right forefoot weight bearing	4.8 × 2.5	Excision of first metatarsal + free fibular graft	19	Yes	No

Complications

There was no case of total flap necrosis in our study (21 cases), although partial necrosis occurred in a case of reverse sural flap for heel defect which was managed conservatively. The wound healed after a few weeks of dressing and the patient was able to walk with custom-made shoes. One patient with free fibular osseus flap for first metatarsal defect developed foot stiffness but despite that, can walk comfortably and was happy with the overall outcome. Partial loss of skin graft was seen in one patient with midfoot defect (non-weight bearing), which healed later with daily dressing. No donor site morbidity was observed in any of the flap cases, either pedicle or free. No additional surgical procedure was needed in the entire case series.

Functional outcome

Functional score was assessed with musculoskeletal tumour society scoring system (MSTS). The mean MSTS score at end of 1 year was 22.71/30 in the series. The lowest score (of 18) was seen in a case of hindfoot defect where there was a partial necrosis of reverse sural flap. The patient was advised custom made shoes for better walking. All the remaining patients regained walking and daily functional activities. There was no sliding or shearing of the flap for the plantar reconstruction. Most of patients regained protective sensation from 3 to 12 months. The younger patients had an earlier recovery of flap sensation. Increased sensation was found in one case with the reverse sural flap, while no sensory recovery was seen in one case with the sural flap reconstruction during follow up.

In our study, gender, diagnosis and side of pathology were found to be non-significant in relation to functional outcome in terms of MSTS score. The parameters including size defect, weight-bearing areas and complications were found significantly related to functional outcome (MSTS score). Outcome and correlation between various parameters are described in Table 2.

Table 2.

Correlation between functional outcome and various clinical parameters affecting the final outcome

				95% CI		p-value
	N	Mean MSTS score	Std. deviation	Lower bound	Upper bound
Gender
Male	11	23.09	1.921	21.8	24.38
Female	10	22.3	2.214	20.72	23.88	0.392
Diagnosis
Melanoma	12	22.5	2.067	21.19	23.81
MPNST	1	22				0.155
Osteosarcoma	1	19
SCC	7	23.71	1.604	22.23	25.2
Side
Right	13	22.46	1.713	21.43	23.5
Left	8	23.13	2.588	20.96	25.29	0.486
Weight Bearing
Weight bearing	16	22.19	2.007	21.12	23.26
Non-weight bearing	5	24.4	1.14	22.98	25.82	0.031
Complications
No	18	23	1.915	22.08	23.92
Yes	3	20	1.414	7.29	32.71	0.046
Size
Large	10	21.6	2.171	20.05	23.15
Small	11	23.73	1.348	22.82	24.63	0.013
Recurrence
No	20	22.75	2.099	21.77	23.73
Yes	1	22				0.731

Statistical Analysis

All calculations were done using SPSS v21 software. In the series, mean MSTS score for all parameters including gender, diagnosis, tumour location, defect size, complications and recurrence was calculated. Student’s t-test was used to assess the correlation among different variables in the series. A p-value < 0.05 was considered statistically significant.

Discussion

Reconstruction of foot defects particularly in weight bearing areas poses a challenge. Various techniques have been employed for this purpose. Hidalgo and Shaw studied the arterial anatomy and the cutaneous nerve supply of the plantar skin extensively in the 1980s, providing guidelines of safe plantar incisions and flap design [5]. Prior to their work, flap designs on the plantar aspect of the foot were based on the concept that blood supply proceeds from the deep to the superficial tissue. Therefore, plantar flaps were usually raised subfascially requiring extensive dissection of the plantar soft tissue and, thus, resulting in severe foot and donor site morbidities. They preferred to cover soft tissue losses less than 3 cm² with local flaps in weight-bearing areas and with skin grafts in non-weight bearing areas (type I). Type II defects which are defined to be larger than 3 cm² without bone involvement were preferred to be covered by free fasciocutaneous, free musculocutaneous flaps or local flaps to ensure a durable soft-tissue coverage preventing recurrent ulcerations, improving the scar qualities and reducing strains on the scars. Large tissue losses with bone involvement (type III) were recommended to be reconstructed with free flaps or free osteocutaneous transfers if necessary [6]. Table 3 provides the comparison of functional outcome of similar studies.

Table 3.

Comparison of functional outcome in similar studies

Study	Mean MSTS score	Mean age (years)	Follow-up period (months)	Number of patients (n)
Xu et al. [7]	21.5	50.8	30	98
Ebeid et al. [8]	27.5	29.2	44	18
Ozger et al. [9]	20	35	32.7	48
Tsuda et al. [10]	26	-	68	50
Our study	22.7	53.1	12	21

In our study, 7 patients underwent skin grafting for coverage of defects at non-weight-bearing areas, with one partial graft loss, and the results of which are comparable to the study by Sang-Woo Kang et al. [11] which reported no donor or graft site complications. In their study, the exposed structures were covered with MatriDerm, and a vacuum device was applied intraoperatively and 1 week later when good granulation tissue (dermal matrix) formed, and a split-thickness skin graft was applied. Both the patients had good functional results and no problems with skin donor sites.

Skin grafting has a few advantages [12] which are as follows:

1. Avoids need to interfere with the vascular anatomy of the leg (like in the local flaps from leg)

2. Early wound closure with least tissue cost so that other options are still possible later

3. Skin grafts adhere to the underlying tissues firmly giving a more secure feeling and stability and lastly

4. Regenerating nerve endings pierce the skin graft more effectively so that sensation can be restored to near normal even causing hyperalgesia in some patients

Disadvantages of the skin graft at the sole is that it takes much more time to carry full weight compared to the flap and chances of cracking of the graft if repeated stress is applied. A good aftercare is important for the skin grafts with emollients to hydrate the graft and customed shoes with silicon innersole if available to reduce stress on the graft.

Due to its reliable vascular supply, its proportions and the moderate donor site defect, the distally based sural flap has proven itself in the coverage of smaller defects at the hind foot and malleolar region [13]. Ciofu et al. [14] in their study report 30% complication rate including partial flap loss and venous congestion. Tan et al. recently reported a case series of such neurotised distally based sural flaps in 14 patients where all flaps survived and two points discrimination achieved at least 14 mm after 6 months. In our study, 9 patients underwent reconstruction with reverse sural artery flap; out of which, one patient had partial necrosis. Most of the patients regained sensation in 6–12-month period.

Plantar rotation flap was used in 1 case for reconstruction in our study. Bofelli et al. [15] used plantar rotation flap to reconstruct defects of foot following amputation. Their study although small provides data for use of local plantar rotation flap as an option for reconstruction of foot defects. Although there was no flap related complication in our study, the patient later went on to have recurrence at the local site.

One patient underwent reconstruction with free radial forearm flap for forefoot defect in our study, with no flap related complications. The study by Weinzweig et al. [16] using radial forearm flap showed a 92% success rate with 2 cases of flap loss and infection in 3 patients. Reconstruction with radial forearm flap may be considered an excellent choice for reconstruction as it provides a stable contour allowing patients to use normal footwear without the need for debulking and provides possible sensory benefits.

Free fibula reconstruction was performed in one patient with metatarsal tumour, the outcome including development of stiffness of joint as complication. St Hilaire et al. [17] in their report described the use of free fibular flap to reconstruct the first metatarsal and achieved a good outcome.

Flexor digitorum brevis (FDB) flap coupled with skin graft, used in 1 patient had no complication and proved another excellent option for weight bearing area of foot. A similar report by Sakai et al. [18] where FDB flap was used to cover lateral sole defect successfully, with the only disadvantage being of desensitization.

Medial plantar flap was used in one case without any complications. Macedo et al. [19] achieved good outcomes with the use of medial plantar artery flap to reconstruct soft tissue defect of foot. This flap can provide local tissue for weight bearing areas while also providing some sensation. The innervated flap can be elevated on either the medial or lateral plantar vessels, both of which are ultimately based on the posterior tibial vessels. The flap can be raised superficial or dep to plantar fascia depending upon need.

Our study is limited to a small number of patients. In the future, incorporation of larger number of patients with longer follow-up period is needed to better evaluate the outcome of reconstruction. A well-planned reconstruction is needed to achieve to achieve a good functional outcome and hence improved quality of life.

Conclusion

The reconstruction of complex defects of the foot has experienced a steady improvement in recent decades. The location of the defect enormously hampers the patient’s quality of life and the peculiar anatomical structure of the plantar foot can make even a small defect a difficult task for reconstruction. Simple skin grafts to local flaps maybe a viable option in a limited resource setting based on the location of defect. Free tissue transfer is the ideal choice in case of weight bearing areas to achieve acceptable outcomes. Also, the importance of postoperative physiotherapy cannot be stressed enough as functional recovery is a long process.

Declarations

Conflict of Interest

The authors declare no competing interests.