Pedicled medial sural perforator flap for the reconstruction of knee defects

Reconstruction of soft tissue defect around knee with thoracodorsal artery perforator flap and muscle-sparing latissimus dorsi flap

INTRODUCTION

Around the knee reconstruction is challenging for reconstructive surgeons. Several methods have been proposed, including perforator and muscle flaps; however, all have advantages and disadvantages. As the success rate of free-flap surgery increases, reconstruction around the knee using this method is becoming increasingly popular. Nevertheless, there are no large-scale case reports in the previous literature using either a thoracodorsal artery perforator flap (latissimus dorsi (LD) perforator flap) or a muscle-sparing latissimus dorsi (msLD) flap for reconstruction around the knee. In this retrospective report, we describe our clinical experiences and present an algorithm regarding recipient vessel choice in free-flap reconstructive surgery of around the knee defects.

PATIENT AND METHODS

Fifty-six cases in which a flap from the lateral thoracic area was used to reconstruct an around the knee defect between January 2016 and March 2022 were reviewed. The patients were aged 18-87 years (mean, 52.13 years), and of the 56 patients, 36 were male and 20 were female. Injuries were caused by trauma, contracture, rheumatoid vasculitis, tumor, infection, burns, sunken deformity, and pressure sores. The 56 cases included 22 with a defect including the knee, 14 with a defect below the knee (7 of the primary below-knee amputation [BKA] and 7 of the secondary BKA), 9 involving the distal medial thigh, 8 involving the distal lateral thigh, 2 involving the popliteal area, and 1 involving the middle thigh. Most cases were reconstructed using a single LD perforator flap or msLD flap. Chimeric or supplementary flaps were used when extensive coverage or dead space obliteration was required. The average size of the defect area was 253.6 cm2 (range: 5 × 6-21 × 39 cm2 ).

RESULTS

In the cases, the recipient artery used included the following: descending genicular artery (23), superficial femoral artery (14), descending branch of the lateral circumflex femoral artery (14), anterior tibial artery (2), popliteal artery (2), and posterior tibial artery (1). The recipient vein included the greater saphenous vein (24), descending branch of the lateral circumflex femoral vein (14), superficial femoral vein (7), descending genicular vein (6), anterior tibial vein (2), popliteal vein (2), and posterior tibial vein (1). The average flap size was 281.8 cm2 (range: 4 × 8-35 × 19 cm2 ). All flaps survived; however, seven complications occurred, including 2 partial flap losses, 1 arterial insufficiency, 1 hematoma, 1 minor dehiscence, 1 donor-site graft loss, and 1 short BKA. Normal knee range of motion (121-140°) was observed in 34 patients and 16 showed varying degrees of limited range of motion. Motion was not observed in four patients who underwent knee fusion and could not be evaluated in two patients who underwent above-knee amputation. The mean follow-up duration was 24.6 months (range: 4-72 months).

CONCLUSION

The LD perforator flap is ideal for the reconstruction of around the knee defects because it enables a long pedicle, large flap, and chimeric design. The msLD flap is ideal because it enables strong stump support, dead-space obliteration, and infection control. Moreover, since the two flaps are distant from the knee, this method is advantageous in terms of postoperative rehabilitation and there is minimal donor-site morbidity due to the thin nature of the LD muscle. In addition, the flap can be elevated in three positions and the operation can be completed without positional changes in various recipient vessel locations. Based on our experience, we conclude that the LD flap has the potential to be used as widely as or in preference to the anterolateral thigh flap in the reconstruction of around the knee defects.

The Medial Sural Artery Perforator Flap: A Historical Trek from Ignominious to “Workhorse”

Rather than just another “review,” this is intended to be an “overview” of the entire subject of the medial sural artery perforator (MSAP) flap as has been presented in the reconstructive literature from its inception in 2001 until the present, with any exceptions not purposefully overlooked. Unfortunately, the pertinent anatomy of the MSAP flap is always anomalous like most other perforator flaps, and perhaps even more variable. No schematic exists to facilitate the identification of a dominant musculocutaneous perforator about which to design the flap, so some adjunctive technology may be highly valuable for this task. However, if a relatively thin free flap is desirable for a small or moderate sized defect that requires a long pedicle with larger caliber vessels, the MSAP flap deserves consideration. Indeed, for many, this has replaced the radial forearm flap such as for partial tongue reconstruction. Most consider the donor site deformity, even if only a conspicuous scar on the calf, to be a contraindication. Yet certainly if used as a local flap for the knee, popliteal fossa, or proximal leg, or as a free flap for the ipsilateral lower extremity where a significant recipient site deformity already exists, can anyone really object that this is not a legitimate indication? As with any perforator flap, advantages and disadvantages exist, which must be carefully perused before a decision to use the MSAP flap is made. Perhaps not a “workhorse” flap for general use throughout the body, the MSAP flap in general may often be a valuable alternative.

The Versatility of the Pedicled Medial Sural Artery Perforator Flap: From Simple to Its Chimeric Pattern and Clinical Experience with 37 Cases

BACKGROUND

Defects in the knee area, popliteal fossa region, and upper third of the lower extremity can pose a challenge for reconstructive plastic surgeons. The purpose of this article is to report the authors' experience with the use of the pedicled medial sural artery perforator flap in its simple and chimeric form for reconstruction of defects in three different regions: knee, popliteal fossa, and proximal lower leg.

METHODS

From April of 2018 to April of 2019, 37 patients (29 men and eight women) with a mean age of 51 years (range, 18 to 78 years) underwent reconstruction with 37 pedicled medial sural artery perforator flaps. All flaps were harvested as pedicled perforator flaps in conventional or chimeric fashion and were based on one or two perforators. The defect locations included the knee (18 cases), popliteal fossa (seven cases), and proximal lower leg (12 cases). The cause of reconstruction was trauma in 22 patients (59 percent), tumor in 10 patients (27 percent), and donor-site closure of free medial sural artery perforator in five patients (14 percent).

RESULTS

The flap sizes varied from 3.5 × 5 cm to 5 × 10 cm. All but one flap, which showed distal tip necrosis, survived completely after surgery. The donor sites were all closed primarily. Minor complications included flap dehiscence (two cases) and minor wound infection delaying the healing process (four cases). All complications were treated conservatively. Follow-up observations were conducted for 3 to 12 months, and all patients had good functional recovery with satisfactory cosmetic results.

CONCLUSION

The pedicled medial sural artery perforator flap can be considered an optimal method of reconstruction for covering defects not only in the knee area but also in the popliteal fossa and upper lower leg.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

The medial sural artery perforator (MSAP) flap: A versatile flap for lower extremity reconstruction

BACKGROUND

The medial sural artery perforator (MSAP) flap provides a thin, pliable and durable soft tissue reconstruction with adequate pedicle length and low donor morbidity. It is an ideal choice for small-to-moderate defects of the lower extremity, although it does have limitations. We report our experience of the flap in a three-pronged anatomical, clinical and patient reported outcome-based study.

METHODS

Cadaveric fresh frozen lower limbs (n = 10) were used for anatomical dissections to assess pertinent and clinically relevant findings. Data relating to MSAP flaps was collected from a prospectively maintained database over a 2-year period. Both clinical data and modified Enneking scores were analysed.

RESULTS

Anatomical study: A mean of 2.1 ± 0.99 perforators arose from the medial sural artery, located 11.9 cm ± 2.07 along the line between the popliteal fossa and medial malleolus. The largest perforator was located 13.58 cm ± 2.01 from the popliteal artery. The distance from the dominant perforator to the first branching point within the gastrocnemius was 7.39 ± 1.50 (range 5-9.2 cm). The short saphenous vein was located on average 3.08 cm ± 0.77 from the dominant perforator. Clinical study: Twenty free and nine pedicled MSAPs were included (n = 29). Open lower limb fractures (n = 18, 62%) and infection (n = 10, 35%) were the most common aetiologies. Defects sites included: foot-and-ankle (n = 12, 55%), knee (n = 9, 31%) and anterior leg (n = 4, 14%). Four patients (14%) required SSG to for donor site coverage. Venous congestion was responsible for partial flap necrosis in 6.9%(n = 2) of patients. All wounds were healed at discharge. At 14 months, the mean Enneking score was 72.5%. All patients were ambulant, 96% returned to work and 87% were using pre-operative footwear.

CONCLUSIONS

The MSAP provides robust foot-and-ankle reconstruction, whilst permitting glide when over the knee. Patient satisfaction and functional outcomes are excellent with careful patient selection. Care should be taken to avoid compression or kinking of the large, thin walled veins as the most commonly observed complication was venous congestion. We advocate MSAP as a first choice flap for small-to-moderate foot, ankle or knee defects.