Pedicled Peroneal Artery Perforator Flap for Knee Defect Reconstruction: Case Presentation and Literature Discussion

Distally Based Anterolateral Thigh Flap Algorithm for Unexpected Situations during Soft-Tissue Defect Reconstruction around the Knee

BACKGROUND

The distally based (d) anterolateral thigh (ALT) flap is an effective option for soft-tissue reconstruction around the knee; however, unexpected situations may occur intraoperatively, impeding flap harvest. The authors proposed an algorithm for surgical conversion for unexpected situations encountered intraoperatively.

METHODS

Between 2010 and 2021, 61 dALT flap harvests were attempted for soft-tissue defect reconstruction around the knee; 25 patients underwent surgical conversion for anomalies, including lack of a suitable perforator, hypoplasia of the descending branch, and compromised reverse flow from the descending branch. After excluding improper cases, 35 flaps were harvested as planned (group A) and 21 surgical conversion cases (group B) were finally enrolled for analysis. An algorithm was developed based on the cases in group B. Outcomes, including complication and flap loss rates, were compared between groups to verify the algorithm's rationality.

RESULTS

In group B, the dALT flap was converted to a distally based anteromedial thigh flap ( n = 8), bipedicled dALT flap ( n = 4), distally based rectus femoris muscle flap ( n = 3), free ALT flap ( n = 2), or other locoregional flap that required additional incision ( n = 4). No differences in outcomes were observed between the two groups.

CONCLUSION

The proposed contingency planning algorithm for dALT flap surgery proved rational, as surgical conversion could be made by means of the same incision in most cases, and outcomes generated by the algorithm were acceptable.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Smart Strategies to Overcome Drug Delivery Challenges in the Musculoskeletal System

The musculoskeletal system (MSKS) is composed of specialized connective tissues including bone, muscle, cartilage, tendon, ligament, and their subtypes. The primary function of the MSKS is to provide protection, structure, mobility, and mechanical properties to the body. In the process of fulfilling these functions, the MSKS is subject to wear and tear during aging and after injury and requires subsequent repair. MSKS diseases are a growing burden due to the increasing population age. The World Health Organization estimates that 1.71 billon people suffer from MSKS diseases worldwide. MSKS diseases usually involve various dysfunctions in bones, muscles, and joints, which often result in pain, disability, and a decrease in quality of life. The most common MSKS diseases are osteoporosis (loss of bone), osteoarthritis (loss of cartilage), and sarcopenia (loss of skeletal muscle). Because of the disease burden and the need for treatment, regenerative drug therapies for MSKS disorders are increasingly in demand. However, the difficulty of effective drug delivery in the MSKS has become a bottleneck for developing MSKS therapeutics. The abundance of extracellular matrix and its small pore size in the MSKS present a formidable barrier to drug delivery. Differences of vascularity among various MSKS tissues pose complications for drug delivery. Novel strategies are necessary to achieve successful drug delivery in different tissues composing the MSKS. Those considerations include the route of administration, mechanics of surrounding fluids, and biomolecular interactions, such as the size and charge of the particles and targeting motifs. This review focuses on recent advances in challenges to deliver drugs to each tissue of the MSKS, current strategies of drug delivery, and future ideas of how to overcome drug delivery challenges in the MSKS.

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.

Lower limb perforator flaps: Current concept

Following a long period dominated by random fasciocutaneous flaps or muscle flaps, solutions to cover the lower limb have been largely diversified by the advent of so-called "perforator" flaps. Extended knowledge of vascular anatomy has propagated the development of this innovative procedure, in the objective of reducing morbidity. The existence of close to 400 perforator vessels in the body makes it possible to offer new flap perspectives for many defects, which were sometimes previously impossible to manage before except by free flap. For us, perforator flaps have become the current first-line solutions for small to medium size loss of substances. Understanding of vascular physiology and surgical experience are essential in choosing indications, detecting perforators, and modeling flaps to be optimally positioned in the reconstructive decisional algorithm. New skills are needed to master this type of reconstruction and limit failures, which implies a learning curve not only for flap design, perforator detection and surgical procedure, but also for monitoring and management of complications. In this manuscript, we outline the concepts and principles of the majority of the pedicled perforator flaps available for coverage of the lower limb, based on experience of more than 400 perforator flaps suitable for this localization.