Soft tissue coverage in open fractures of tibia.

BACKGROUND: The treatment of Gustilo Anderson type 3B open fracture tibia is a major challenge and it needs aggressive debridement, adequate fixation, and early flap coverage of soft tissue defect. The flaps could be either nonmicrovascular which are technically less demanding or microvascular which has steep learning curve and available only in few centers. An orthopedic surgeon with basic knowledge of the local vascular anatomy required to harvest an appropriate local or regional flap will be able to manage a vast majority of open fracture tibia, leaving the very few complicated cases needing a free microvascular flap to be referred to specialized tertiary center. This logical approach to the common problem will also lessen the burden on the higher tertiary centers. We report a retrospective study of open fractures of leg treated by nonmicrovascular flaps to analyze (1) the role of nonmicrovascular flap coverage in type 3B open tibial fractures; (2) to suggest a simple algorithm of different nonmicrovascular flaps in different zones and compartment of the leg, and to (3) analyze the final outcome with regards to time taken for union and complications.
MATERIALS AND METHODS: One hundered and fifty one cases of Gustilo Anderson type 3B open fracture tibia which needed flap cover for soft tissue injury were included in the study. Ninety four cases were treated in acute stage by debridement; fracture fixation and early flap cover within 10 days. Thirty-eight cases were treated between 10 days to 6 weeks in subacute stage. The rest 19 cases were treated in chronic stage after 6 weeks. The soft tissue defect was treated by various nonmicrovascular flaps depending on the location of the defect.
RESULTS: All 151 cases were followed till the raw areas were covered. In seven cases secondary flaps were required when the primary flaps failed either totally or partially. Ten patients underwent amputation. Twenty-two patients were lost to followup after the wound coverage. Out of the remaining 119 patients, 76 achieved primary acceptable union and 43 patients went into delayed or nonunion. These 43 patients needed secondary reconstructive surgery for fracture union.
CONCLUSION: open fracture of the tibia which needs flap coverage should be treated with high priority of radical early debridement, rigid fixation, and early flap coverage. A majority of these wounds can be satisfactorily covered with local or regional nonmicrovascular flaps.

INTRODUCTION

The incidence of open fracture tibia as a part of isolated injury or polytrauma is on the rise due to increase in the incidence of motor vehicle accidents. Gustillo Anderson type 3B open fracture tibia has been a major Challenge for the entire team of trauma surgeons involved in the treatment. The need for aggressive debridement, adequate fracture fixation, and early flap coverage in reducing the morbidity cannot be over emphasized.1 This is possible only when there is a collective osteoplastic approach to the problem rather than the conventional orthopedic approach alone.2 The flaps used to cover the soft tissue defects in open fracture of the tibia, could be nonmicrovascular, which are technically less demanding or microvascular, involving steep learning curve and available only in few centers in a developing country like ours. An orthopedic surgeon equipped with theoretical and practical knowledge of the local vascular anatomy required to harvest an appropriate local or a regional flap to cover the exposed bone or metal in fracture tibia, will be able to manage a vast majority of open fracture tibia, leaving the very few complicated cases needing a free microvascular flap to be referred to specialized tertiary center. This logical approach to the common problem will lessen the burden of the higher tertiary center of dealing with relatively simpler cases needing nonmicrovascular flaps.

There has been a shift in the approach for the treatment of soft tissue defects in open fractures favoring nonmicrovascular flaps, to time-consuming and tedious free flaps.3 The advent of reliable, robust and technically less demanding distally based sural artery flap4 has allowed to cover small and moderate sized soft tissue defects in the distal one third of leg, which was once considered as territory for a microvascular flap. The decreasing trend of the usage of microvascular flaps in the acute lower limb trauma is also due to fairly high incidence of failure and the cost of the treatment. The injured limbs in failed free flap surgeries are even more difficult to salvage. These factors justify the usage for free flaps only when the local or regional flaps are not feasible either because of the size or extensive local tissue trauma.4a

We report a retrospective study of open fractures of leg treated by nonmicrovascular flaps to analyze (1) the role of nonmicrovascular flap coverage in type 3B open tibial fractures; (2) to suggest a simple algorithm of different nonmicrovascular flaps in different zones and compartment of the leg, and to (3) analyze the final outcome with regards to time taken for union and complications.

MATERIALS AND METHODS

Between 1989 and 2006, 151 cases of Gustilo Anderson type 3 open fracture tibia which were seen and treated by flap coverage by first author (JBK) were included in the study. The inclusion criteria was type 3 open fractures of the tibia in which soft tissue defect could be managed by nonmicrovascular flap. Open fracture tibia which were treated by split skin grafting, free flap or which were amputated before any reconstructive surgery were excluded from the study.

The data was obtained from the hospital medical records department. The average age 33.9 years (range 7-78 years) with maximum patients (n=52) were between 21-30 years of age group. There were 133 males and 18 female patients in the study. There were 151 cases of type 3B fractures in the study. Out of this, 27 cases were initially classified as type 3A and were reclassified as type 3B after two or three debridements, and 2 cases were actually type 3C but were misdiagnosed as type 3B and were treated with flap cover. The limb which was surviving on only one vessel in these 2 cases went into acute vascular thrombosis and had to be amputated in early phase after the flap cover. Hence, all the cases were type 3B according to us before flap coverage.

Ninety four cases reported to us within 10 days of injury (Group A). Thirty Eight cases reported between 10 days to 6 weeks (Group B) and the remaining 19 cases reported after 6 weeks (Group C) after injury. All the cases underwent debridement and skeletal stabilization as soon as they reported to us. The raw area was covered by flap immediately when we were sure of our debridement. In cases where there was doubt, we waited till the infection was under control before doing a flap. The 151 cases treated within the period of 18 years were grouped into 3, depending on the period, namely period 1 (n=44): between 1989 and 1995, period 2 (n=58): between 1995 and 2000, period 3 (n=49) between 2000 and 2006. During the early part in period 1, the large fasciocutaneous flaps used to be in stages by “delaying” the flap. This means that the flap was marked and incised on its three borders in stage one and the actual raising and rotation of flap was done in stage two. This was the time we started using tubular external fixator.

In the early part of group 2, we started using the distally based sural artery flap5 in middle and distal third in which “delaying” was not required and the entire procedure could be done in one stage. During the beginning of group 3, we started using the hand held Doppler to identify the perforators and started using fasciocutaneous flaps from the anterolateral compartment6 with the length: breadth ratio of up to 3:1 or 4:1 with very narrow nonskeletonized perforators. We also started using external fixator to protect the pedicle and split skin grafting (SSG) by keeping the leg elevated, avoiding the pressure over the pedicle and the grafted area.7

The tibial fractures were treated with external fixation in 82 cases and with interlocking nailing in 69 cases. Percutaneous K wire or cannulated cancellous screws were used in 13 cases in periarticular region at the knee or ankle. The method of fracture management depended mainly on the fracture personality and their time of presentation. All fractures were nailed primarily when they presented in acute period. Periarticular metaphyseal fractures were treated with external fixator. All delayed presentations were initially treated with an external fixator. Percutaneous K wires and cannulated cancellous screws were used as supplement wherever required. Twelve patients underwent secondary nailing after wound coverage and control of infection.

Postoperative protocol was nonweight bearing mobilization and foot elevation till the flap settled. Touch down weight bearing was allowed only after early callus was seen. Union was assessed radiologically in nailing cases. In cases where external fixator were used, once the flap settled the external fixator was removed and Plaster of Paris cast was applied. After 6-8 weeks of cast application, union was assessed clinically and radiologically (continuity of three cortices). When union did not occur within 9 months we termed it nonunion. Delayed union was in between 6 and 9 months.

The details of different methods of fracture management are given in Table 1. The time period divides our work roughly into three parts. We were exposed to distally based sural artery flap and flaps based on perforators (detected by hand held Doppler machine) in the second and third period respectively. These factors dictated the procedure of choice in the three time periods.

Table 1

Details of different methods of fracture management in all groups

The leg was divided into proximal, middle, and distal zones as well as into anteromedial, anterolateral, posteromedial, and posterolateral compartment to describe the soft tissue defect. The soft tissue defect was predominantly in proximal one third of the leg in 33 cases, middle one third in 45 cases, and distal one third in 66 cases. In two cases, the wound was extending into proximal and middle one third and in other four cases the wound was involving middle and distal one third. In one case, all the three zones were involved.

The soft tissue defect was confined only to the anteromedial compartment in 108 cases, to anteromedial and anterolateral compartment in 16 cases, to anteromedial and posteromedial compartments in 22 cases, to anteromedial and posterolateral compartment in 03 cases. In two cases, anteromedial, anterolateral, and posteromedial compartment were involved [Table 2]. Seven secondary flaps were used in seven cases where the primary flaps failed either totally or partially. (Four cross leg flaps and three fasciocutaneous flaps from the adjacent compartment).

Table 2

Various primary flaps used to cover the open fracture tibia

RESULTS

The road traffic accidents occured in 92 cases, fall from height in 38, domestic injury in 14, and farm injury in 7 cases. 69 patients had polytrauma (more than three skeletal or nonskeletal associated injuries). Twenty-seven patients had less than two associated injuries and 55 patients had isolated open fracture of the tibia. All 151 cases were followed till the raw areas were covered. 10 patients underwent amputation after the attempt of reconstructive surgery. Twenty-two patients were lost to followup after the wound coverage for various reasons. Out of 119 remaining cases,76 cases achieved primary acceptable union and 43 patients went into delayed or nonunion. The average time taken for union of the fracture tibia was 8.4 months (5.3–30 months). These 43 patients needed secondary reconstructive surgery for the fracture union once the superficial or deep infections was ruled out. Out of these 43 patients, eight needed bone grafting, two needed Huntington procedure, 15 patients needed bone transportation using Ilizarov, seven patients needed Ender's nailing and bone grafting and 5 patients were treated by exchange nailing and bone grafting. Six patients refused further treatment and were left alone.

The details of the complications encountered are as follows: out of 94 flaps done in the group A, deep infection was seen in16 cases; a second flap was required in 2 cases where there was total loss of flap and also in 2 cases where there was partial loss of flap. Marginal loss of flap occurred in 12 cases, which was managed either conservatively or by SSG. Amputation was required in 2 cases.

Out of the 38 flaps done in the group B, deep infection was seen in 21 cases and a second flap was required in 3 cases where there was partial loss of flap. Marginal loss of flap occurred in 4 cases, which was managed either conservatively or by SSG. Amputation was required in 4 cases.

Out of the 19 flaps done in the group C, deep infection was seen in 7 cases and a second flap was required in 1 case where there was partial loss of flap. Marginal loss of flap occurred in 2 cases, which was managed either conservatively or by SSG. Amputation was required in 4 cases.

DISCUSSION

Open fractures of tibia have always been a challenge for the surgeons and physio and occupational therapists. While type 1, 2, and 3A open fractures of tibia have relatively favorable outcome because of simpler soft tissue components of the injury which could be managed either as a primary, delayed primary closure, or with split thickness skin graft, the types 3B and 3C need thorough initial management of fracture and has to be followed by early wound closure. This can be carried out using a viable tissue available locally, regionally or from a distant location. With the advent of newer local regional flaps in the form of proximal or distally based perforator fascio cutaneous flaps,6 muscle or myocutaneous flaps and judicially used cross leg flaps, majority of the wounds associated with the open fractures of the tibia can be covered by orthopedic surgeons with the armamentarium of sound principles and atraumatic techniques. The need for free or microvascular flaps in the management of open fractures of the tibia should be restricted to few large wounds where local regional flaps are not feasible. Although the free tissue transfers can be limb saving in selected cases of type 3B open fractures of tibia, there is a decrease in the tendency of trauma surgeons to resort to free microvascular flap cover where local regional flaps are feasible. This is because free flaps are associated with greater medical complications, longer operative time, and hospital stay. Acute microvascular free flaps for open fracture tibia are not only technically demanding but also has high incidence of flap loss up to 25% which is unacceptable and difficult to salvage. They may be more useful in chronic conditions when free tissue can be brought as a composite flap along with bone tissue.

There are many time tested robust local flaps used to provide soft tissue coverage in compound fractures of the tibia. But failure of one procedure may jeopardize the 2nd salvage flap from the same or neighboring compartment. Selection depends on the site, size, and the nature of injuries, age of the patient, comorbid conditions of the patients and expertise of the trauma surgeons. Conventionally, the selection depends on the site of the raw area namely proximal ⅓, middle ⅓, and distal ⅓. Due consideration should also be given to the zone of injury and the zone of intact soft tissue for harvesting a flap in different quadrants or compartments of the leg, namely anteromedial, anterolateral, posteromedial and posterolateral. The debridement of the wound in open fracture should be thorough, radical, and centripetal, using the loupe magnification and torniquet. Once all the nonviable and doubtfully viable nonvital structures are removed (except tendon, nerves, and vessels) the trauma surgeon has to reassess the wound. He also needs to carefully assess the apparent and real dimensions of the wound with respect to the feasibility of the local flaps, because a viable, partially injured and undermined or degloved skin margin cannot be a reliable part of the local flap for advancement, rotation, or transposition. This part of the grey zone of the injury is amenable for assessment only by the primary surgeon during the first debridement, which is why the initial management of the open fracture must be one of the orthoplastic approach rather than pure orthopedic approach. The grey zone of the injury should be documented both pictorially and in case sheet records following the primary debridement. It is this extent of the grey zone of injury and the spatial relationship of the grey zone of the injury to the vascular axis along which the septocutaneous perforators arise from three major arterial systems of the leg, that has to be assessed and confirmed following primary debridement to choose an ideal local flap either in the primary setting or during the first or the second look. Occult injury to the muscles should also be assessed following primary debridement. If surgical extension of the wound is required for proper debridement or bony alignment, it should be done carefully and should not jeopardize the simpler regional cutaneous or muscle flaps. Placement of pins and frame of the external fixator should also facilitate easy transposition and rotation of local flaps and not be a hindrance for the same. In the fracture tibia an extensive wound which needs a cross leg flap, should ideally be externally fixed with an anterior or anterolateral frame, because a medial frame may come in the way of easy positioning of the contralateral leg during the postoperative period.

Some local flaps preclude the options of some secondary procedures. A good example of this would be the donor site of the distally based sural artery flap cover will rule out the chances of a posterio-lateral Harmons bone grafting at a later date. Any medial flap resulting in SSG coverage in the distal 1/3 of the leg on the medial or posterior or anterior compartment will be detrimental for the secondary tendon transfer for a foot drop if need arises. Hence, a primary surgeon performing the debridement and the fracture fixation must have some idea regarding the different options which will not only be easy and useful but also non-interfering with the secondary reconstructed procedures.

As our series is large spanning for about 17 years, where the open fracture of tibia were treated both by external fixator and interlocking nails with different locoregional flaps in different phases of the post-injury period, it will be difficult to compare our result with other series.

However, our result in terms of union rate of 64% (76/119) primary union (without any secondary skeletal surgical intervention other than debridement for deep infection) and 31% (37/119) of secondary union (cases which needed multiple soft tissue and bony reconstructive procedures) is comparable to the previously reported series.8

The average time taken for union in 113 patients out of 151 in our series was 8.4 month (5.3 to 30 months) is also comparable with the same series.

The incidence of deep infection of 30% (44/151) in our series is comparable with 22.7% reported by Patzakis et al.9 Our failure rate in terms of timing of flap coverage, largely due to deep infection has been 16.5% (16/94) in group A, 55.25% (21/38) in the group B, and 41% (7/17) in the group C which is comparable to the results published by Henry Stephenson Byrd10 where the corresponding figures are 5%, 50%, and 40%, respectively. Deep infection hindered primary healing of flaps and resulted in chronic osteomyelitis.

The medial head of gastrocnemius muscle11 or the medial gastronemius myocutaneous flap has been the work horse in the soft tissue coverage of defects associated with open fractures in the proximal 1/3 of the leg. This muscle can be used more effectively for this purpose by using the 7 different maneuvers described by Arnold.12 Cavadas13 has used ¼ gastrocnemius muscle flap by splitting the medial head gastrocnemius to cover small areas in very muscular individuals minimizing the donor defect. Moscona14 showed both clinically and in cadavaric dissection that each head of the gastrocnemius muscle can be divided into two, to cover two adjacent areas or one segment to fill the cavity and other to cover the raw area. Recently, Ikuo Hyodo et al15 showed that in larger defects in the proximal half of the leg gastrocnemius muscle with soleus, a bimuscle flap can be raised based on the perforaters connecting the medial gastrocnemius and soleus in the distal half of the belly of the muscle. Some of the other muscles that can be used in the proximal tibia and around knee are distally based vastus lateralis flap,16 distally based short head of biceps muscle flap with lateral intermuscular septum,17 split tibialis anterior muscle flap18 for small areas. There are some flaps described based distally, raised from the thigh for the soft tissue coverage in the proximal 1/3 of the leg, namely distally based pedicled anterolateral thigh flap,19 lower posterolateral thigh flap,20 popliteo posterior thigh flap21 and distally based saphanous artery island fasciocutaneous flap.22 Some of the local flaps available in the proximal 1/3 leg are posterior calf island fasciocutneous flap,23 fasciocutaneous flaps based on perforators of the antierior tibial artery,6 and medial sural artery fasciocutaneous flap.23a

Our recommendation for the coverage of defects in the proximal 1/3 tibia are medial gastrocnemious muscle or myocutaneous flap [Figure 1], perforator based fasciocutaneous flap from the anterior tibial artery, and saphanous artery flap.

Figure 1

Clinical photographs showing (a) Open fracture tibia in the proximal third with nonvital overlying soft tissue. (b and c) The raw area was debrided and covered with medial gastrocnemious flap after external fixation of fracture. (d) Functional status after 4 months

The distal 1/3 of the tibial defects is the real challenge for the reconstructive surgeons. Although proximally based EDL, EHL, FDL and Peroneous tertious24 and brevis25 muscle flaps are described, soleous26 muscle flap (particularly distally based) is more versatile in the distal 1/3 of the leg. Distally based sural artery flap,5 supra malleolar flap,27 fasciocutaneous flap from the calf, based distally can be used either in single stage28 or as a multistage29 procedure. The reversed anterior tibial artery flap,30 reversed neuro fasciocutaneous island flap based on the vessels accompanying superficial peroneal nerve31 are some of the other flaps described in the distal 1/3 the leg [Figure 2 and 3].

Figure 2

(a and b) Clinical photographs showing raw area over distal third of the leg which is covered with distally based anterior tibial artery perforator fasciocutaneous flap

Figure 3

Preoperative clinical photograph showing raw area over the distal third leg (a and b) Postoperative clinical photograph showing the raw area has been covered with distally based posterior tibial artery perforator flap (c and d) preoperative anteroposterior and lateral views showing fracture both bones leg lower 1/3 (e and f). The postoperative X-ray anteroposterior and lateral views showing fracture fixed with an inter locking nail

Our recommendations for the soft tissue defects in the lower third of the leg are distally based sural artery flap,5 distally based perforator flap from the anterolateral compartment,6 and distally based fasciocutaneous flap from the calf.

In the soft issue defects in the middle 1/3 the leg, both proximally and distally based flaps used in the proximal and distal 1/3 defects can be performed [Figure 4]. However, soleus muscle flap26 is extremely versatile and is the preferred flap when there is cul-de-sac to be filled.

Figure 4

(a and b) Clinical photographs showing raw area over the middle third leg exposing the fracture site which has been fixed with an external fixator and wound covered with a proximally based anterior tibial artery perforator fasciocutaneous flap

Cross leg flaps based medially, proximally, or distally have been revisited, and are simple, reliable, and versatile for larger defects in any of the three zones of the leg [Figure 5]. They may be used primarily or following failed ipsilateral or free flaps. Entire length of the leg and nearly whole of the width of the leg expect the pretibial skin can be used other cross leg flap along with the fibula raised as an osteofasciocutaneous cross leg flap.32

Figure 5

(a and b) Clinical photographs showing raw area over the mid third leg, exposing the fracture site which has been fixed with inter locking nail. Postoperative picture after 3 months showing well-healed cross leg flap

Limitation of study is that we have not considered the exact size and area in terms of square cm, in our study and as it covers a heterogeneous group which was treated with different modalities of fixation as our methodology changed. We strongly recommend cross leg flap if the size of the wound to be covered is large enough and exceeds more than 1½ zones or 1½ compartments. The use of external fixator to maintain the cross legged position during the postoperative period has made the cross leg flap more versatile for the surgeon and more acceptable for the patient, making the nursing care much easier.

We recommend the following algorithm to be followed while deciding the various flaps based on the zone and compartment involved [Figure 6].

Figure 6

Algorithm recommending various flaps based on the location of the raw area

To conclude open fracture of the tibia which needs flap coverage should be treated with high priority of radical early debridement, stable internal fixation followed by early flap coverage at an appropriate time, preferably in first 5 days.