**Region:** Lower Extremity # Rectus Femoris Flap ## Anatomy - Pedicle: descending branch of the lateral femoral circumflex artery (LFCA) with venae comitantes. Mean arterial caliber reported 2.1 mm; mean venous caliber 2.3 mm. Pedicle length commonly reported ≈5 cm (individual series report 2–5 cm). The LFCA branch to rectus femoris typically emerges 1–2.5 cm distal to the LFCA origin from the profunda femoris. After giving the rectus branch the LFCA continues inferiorly in the septum to supply the vastus lateralis/anterolateral thigh axis. (sources: Shridharani; Butler/Butler & Mericli) - Course: the major pedicle enters the rectus femoris on its deep and lateral surface at the level where the sartorius crosses the muscle. Minor (distal) pedicles: one to three small branches from the superficial femoral artery enter the distal deep surface; these minor pedicles are generally not sufficient alone to sustain the flap. (Butler; Hanasono) - Perforator pattern / angiosomes: muscle-type dominant supply (Mathes–Nahai type II) — single dominant proximal pedicle with distal segmental minor pedicles. When designing a subtotal thigh/chimeric flap, the LFCA axis supplies adjacent anterolateral thigh (ALT) skin, vastus lateralis, and tensor fascia lata territory; subtotal skin paddle area >400 cm2 reported. (Butler; Lin & Butler) - Nerves: - Motor: muscular branch from the femoral nerve (enters medial proximal aspect of muscle) — divide the nerve during harvest when an innervated flap is not required to avoid undesirable contraction. - Sensory: skin overlying the muscle supplied by intermediate femoral cutaneous nerve; when including cutaneous territory for sensate transfer, identify relevant cutaneous nerves (posterior thigh flap note: posterior femoral cutaneous nerve is within same sheath as descending inferior gluteal vessels ~72% — for comparison of thigh nerve relationships). (Butler; Hanasono) - Included tissues: muscle-only flap (buried or skin-grafted) or myocutaneous flap with skin paddle centered directly over the muscle. Skin-paddle width generally up to 8–9 cm allows primary donor-site closure; myocutaneous maximum skin island reported 10 cm × 30 cm in some series (Shridharani) but reliability decreases distally and in obese patients. Subtotal thigh/chimeric flap can include rectus femoris + vastus lateralis + ALT skin + iliotibial band/tensor fascia lata. - Thickness/arc: rectus femoris is a central quadriceps muscle spanning hip and knee — flap reaches lower abdomen, mons, lateral hip, perineum, groin as a pedicled flap; pedicled subtotal thigh flap can reach the umbilicus. Passing flap deep to sartorius yields ~5 cm additional advancement. Free transfer is used for mid/superior abdominal defects or when longer reach/recipient vessels required. (Butler; Hanasono) - Common variants/anomalies: occasional absence or variant origin of descending branches; minor pedicles variable (1–3). In a minority the LFCA anatomy and perforator reliability may be compromised by atherosclerotic disease. ## Dissection Steps 1. Positioning, markings, landmarks. - Position: supine with bilateral legs internally rotated at the hip. Secure forefeet to avoid pressure. (Butler; Hanasono) - Landmarks/markings: - Mark ASIS and superolateral border/midpoint of patella; connect to approximate lateral border/central axis of rectus femoris. - Extend a line from midpoint of patella to ASIS to represent central axis; mark pivot/pedicle region ~10 cm distal to ASIS (LFCA pedicle localizes ≈10 cm distal to ASIS in cadaveric/surgical description). For myocutaneous skin paddle, design an ellipse centered over the muscle; recommended skin-paddle width up to 8–9 cm for primary closure. For two-incision/minimally invasive harvest: plan a short distal incision 6–8 cm in length directly over distal muscle (4–6 cm proximal to patella for muscle-only approach) and a proximal incision over the major pedicle. (Shridharani; Hanasono; Butler) 2. Plane (suprafascial/subfascial), perforator identification (handheld/IO Doppler). - Initial incision through skin/subcutaneous tissue to level of deep fascia over muscle. Raise medial and lateral adipocutaneous flaps at level of muscle fascia to expose muscle fascia. - Perforators: minor distal muscular perforators from superficial femoral artery encountered and divided/ligated during deep dissection. Use handheld Doppler selectively to localize cutaneous perforators if designing a skin paddle or to confirm pedicle (posterior thigh flap text explicitly recommends Doppler for its pedicle; rectus authors advise CTA if vascular disease suspected). (Shridharani; Hanasono; Butler) 3. Pedicle dissection: exposure, control, division; transfer/inset; perfusion checks. - Distal disinsertion: leave a 2–3 cm cuff of patellar tendon with the muscle to aid inset and suture fixation. - Circumferentially free rectus femoris from vastus medialis/lateralis and underlying vastus intermedius by blunt/sharp dissection; take care laterally where plane with vastus lateralis may be indistinct and requires sharp/electrocautery dissection. - Identify sartorius crossing obliquely; retract sartorius medially to expose major pedicle entering deep/lateral surface at this level. - Dissect pedicle proximally to junction with profunda femoris/LFCA to gain additional length for free transfer or rotational freedom. When freeing pedicle leave venae comitantes intact and ligate small muscular perforators encountered. - Divide motor nerve to muscle unless planning an innervated/dynamic reconstruction. - Subsartorial transposition: pass flap deep to sartorius to gain ≈5 cm extra reach. - Transfer/inset: inset muscle with deep surface oriented per defect needs; if skin required either inset myocutaneous paddle or skin-graft the muscle. Use the preserved tendon cuff for anchoring sutures; avoid placing high-tension sutures directly through muscle belly to minimize tearing. - Free flap options / pedicle length strategies: - Transect rectus branch where it emerges from LFCA to preserve ALT/vastus lateralis if planning free transfer. - Ligate distal LFCA just distal to rectus branch and divide more proximally to gain additional 2–3 cm pedicle length (trade-off: sacrifices ALT/vastus lateralis for future use). - When recipient vessels are distant or deep inferior epigastric system unavailable, create a saphenous vein arteriovenous loop: divide distal saphenous, anastomose end-to-side to superficial femoral artery, position loop adjacent to flap pedicle, divide loop at apex to provide arterial and venous grafts. (Butler; Hanasono; Shridharani) - Perfusion checks: clinical assessment (color, turgor), Doppler confirmation of pedicle flow; preoperative CTA recommended if peripheral vascular disease suspected. (Butler; Hanasono) 4. Donor-site closure techniques. - Reconstruct quadriceps tendon/complex meticulously to minimize donor morbidity: approximate vastus lateralis tendon to vastus medialis tendon with buried permanent sutures, centralizing the remaining quadriceps moment arm. Tenorrhaphy may be extended proximally 10–15 cm to optimize mechanics. - Place closed-suction drains in donor site. Close soft tissues in layers; for skin-paddle width <8–9 cm primary closure generally possible; wider flaps (>9 cm) commonly require split-thickness skin graft. Immobilize knee postoperatively in a knee immobilizer/splint (recommendations in literature: wear during ambulation for 3–6 weeks or 6 weeks depending on source). Early ambulation with weight bearing as tolerated is encouraged. (Butler; Hanasono; Shridharani) ## Indications and Contraindications - Indications: - Pedicled rectus femoris: defects of lower abdomen, groin, mons, perineum, lateral hip; groin and perineal reconstruction, ischial defects in some series. (Butler; Hanasono) - Free rectus femoris: abdominal wall reconstruction (mid/superior abdomen), chest, head and neck, dynamic/functional transfers in select cases. - Subtotal thigh/chimeric pedicled or free flap (rectus femoris + vastus lateralis + ALT skin + ITB/TFL): massive abdominal wall defects; bilateral flaps or combination with mesh for fascial support; subtotal skin paddle >400 cm2 reported. (Lin & Butler; Butler) - When an innervated/dynamic reconstruction is desired, an innervated rectus femoris flap can be used for dynamic abdominal wall reconstruction (reported in case series). (Koshima et al. cited) - Size limits / thickness: - Skin paddle up to 8–9 cm width generally allows primary donor-site closure; myocutaneous island dimensions cited up to 10 × 30 cm in some texts but distal reliability decreases. (Shridharani; Butler) - Contraindications / relative limitations: - Severe ipsilateral vascular disease of LFCA/ profunda femoris (consider CTA preop). - Prior surgery disrupting LFCA / prior ALT/vastus lateralis harvests on same side that consume the LFCA axis. - When preservation of quadriceps strength is critical (athletes) consider potential decreased extension strength — counsel patients. - Obesity: unreliable distal skin paddle/perforators for myocutaneous design; may require skeletonization or alternative flaps. (Shridharani; Hanasono) ## Postoperative Care - Monitoring schedule/method: - Clinical monitoring of flap perfusion (color, turgor, capillary refill), audible/peripheral Doppler assessment when applicable. Preoperative CTA if vascular disease suspected. (Butler; Hanasono) - Drains: closed-suction drains placed under donor and inset sites; manage according to drain output. - Immobilization/positioning: - Knee immobilizer/splint recommended postoperatively to protect donor-site repair. Wear continuously during ambulation for typical periods reported as 3–6 weeks or 6 weeks (sources vary). Keep limb elevated when not ambulating. (Shridharani; Butler; Hanasono) - Mobilization: - Ambulation encouraged as early as postoperative day 1 with weight-bearing as tolerated, while wearing immobilizer. Begin formal physical therapy program focused on quadriceps strength and ROM per institutional protocol. (Butler; Hanasono) - Analgesia / diet: - Standard multimodal analgesia as per institutional pathway (not specifically detailed in sources). - Antithrombotic practice: - Specific anticoagulation protocols not detailed in the provided sources; follow institutional/vascular surgery guidance when vein grafts/AV loops used. - Return-to-OR thresholds and time windows: - The provided sources do not specify strict numeric thresholds for return to OR. Management should follow standard reconstructive principles: any signs of acute arterial insufficiency or progressive venous congestion warrant immediate re-exploration. ## Complications (rates & management) - Flap survival: - Flap loss as a muscle flap reported as negligible in cited series; when elevated as a subtotal thigh myocutaneous flap distal tip skin necrosis reported ≈2%. (Butler; Lin) - Donor-site complications: - Donor-site wound separation: 3–4% reported. - Donor-site hematoma: similar rate 3–4% reported. - Functional morbidity: range of motion often unaffected; measured decreases in knee extension power noted in one quantitative assessment: concentric contraction decreased 10.3%; eccentric contraction decreased 19.3%. Other series report no loss in capacity in many patients. (Butler; Caulfield; Sbitany) - Infection / fat necrosis: - Specific numeric rates for infection/fat necrosis are not provided in the cited material for rectus femoris specifically. - Management algorithms: - Re-exploration: not numerically described in sources; standard practice applies — urgent return to OR for threatened flap (signs of arterial insufficiency or progressive venous congestion). - Distal skin necrosis in subtotal/myocutaneous flaps: manage expectantly or with debridement and local wound care / grafting depending on size and depth. - Donor-site wound separation/hematoma: evacuate hematoma and close/irrigate as indicated; treat wound separation with local wound care and, if needed, operative revision. - Functional deficit: treat with protected immobilization initially (knee immobilizer 3–6 or 6 weeks as reported), then formal physical therapy focusing on quadriceps strengthening; tenorrhaphy at time of closure reduces morbidity. - Numerical complication frequencies included only when reported above. ## Key Clinical Pearls - Mark ASIS and midpoint of patella; central axis between them approximates rectus femoris — mark pedicle/pivot ~10 cm distal to ASIS. (Shridharani; Hanasono) - Preserve a 2–3 cm cuff of patellar tendon on the muscle at disinsertion to provide a durable handle for inset sutures. (Butler; Shridharani) - Passing the flap deep to the sartorius (subsartorial transposition) gains approximately 5 cm of additional advancement. (Butler; Hanasono) - Expect a short pedicle (≈5 cm); plan free transfers with vein grafting or pedicle-lengthening maneuvers if needed (transect rectus branch at LFCA to preserve ALT or ligate distal LFCA to gain 2–3 cm at cost of ALT future use). (Butler) - Skin paddle width up to 8–9 cm typically allows primary donor-site closure; skin paddles wider than ~9 cm often require split-thickness skin grafting. (Butler) - When using subtotal thigh/chimeric flap for very large abdominal defects, the skin paddle can exceed 400 cm2; donor closure will usually require grafting. (Lin & Butler) - Reconstruct the quadriceps tendon complex with robust tenorrhaphy (vastus lateralis to vastus medialis) and place the patient in a knee immobilizer during initial healing to minimize loss of terminal knee extension; anticipate formal PT thereafter. (Butler; Hanasono) - Preoperative vascular imaging (CTA) should be obtained if peripheral vascular disease is suspected to confirm LFCA/profunda patency prior to harvest or when planning free transfer. (Butler; Hanasono)