Rotationplasty of the Lower Extremity



Rotationplasty of the Lower Extremity


Samer Attar

Robert J. Steffner

Terrance Peabody





ANATOMY



  • The distal limb is rotated 180 degrees. This technique permits the rotated ankle joint to function as a knee joint for prosthetic fitting (FIG 1).


  • The stump can fit into a modified below-knee prosthesis that is end-bearing, as opposed to ischial-bearing prostheses for above-knee amputations.


PATIENT HISTORY AND PHYSICAL FINDINGS



  • Historically, rotationplasty has been described in the management of femoral bone loss from tuberculosis, proximal femoral focal deficiency, and sarcomas.1,2


  • Indications for rotationplasty



    • Congenital bone loss or deficiency


    • Sarcomas of the lower extremity


    • Trauma


    • Failed arthroplasty


    • Skeletally immature patient or active adult patient


  • Contraindications



    • Pre-existing nerve damage or ankle stiffness


    • Sciatic nerve involvement in tumor requiring its resection


  • Physical examination



    • The soft tissues proximal and distal to the area of tumor must be intact and free of disease.


    • The ankle joint must be inspected for any contractures or limitations to motion.


    • The dorsalis pedis and posterior tibialis pulses must be inspected for flow.


    • Ankle extension, ankle flexion, and extensor hallucis longus motor strength must be documented.


    • A sensate foot with 5/5 motor strength and full ankle range of motion is ideal.


IMAGING



  • Limb lengths of both lower extremities are obtained.


  • Bone age should be approximated as the nonoperative limb will continue to grow.


  • In malignant bone tumors about the knee undergoing resection, the distal femoral and proximal tibial growth plates are usually removed.


  • When the patient reaches skeletal maturity, the rotated tibiotalar joint of the operative limb should be located at the center of rotation of the knee of the nonoperative limb.


  • The projection of growth of the nonoperative limb must be taken into consideration at the time of surgery. Therefore, in a skeletally immature individual, the operative leg must be longer than the nonoperative femur.


  • In the setting of sarcoma, magnetic resonance imaging determines where to resect the femur with an adequate margin, whether the joint is contaminated, and whether vascular structures are contaminated.



    • If there is joint invasion, an extra-articular resection should be performed.


    • If tumor infiltrates or encases vessels, vascular resection with anastomosis should be considered.


    • The tibial and peroneal nerves should be intact and free of disease as they will be required to power ankle motion.






FIG 1 • Limb after rotationplasty, allowing the rotated ankle joint to function as a knee joint for prosthetic fitting.



SURGICAL MANAGEMENT



  • Operative intervention must focus on the creation of appropriate flaps, wide resection of bone and soft tissue margins, and stable fixation of the remaining femur to the rotated tibia.


Preoperative Planning



  • Extensive discussions with the patient and family are essential prior to performing a rotationplasty. The options of an amputation vs internal prosthesis must be reviewed in addition to explaining their respective risks/benefits.


  • Imaging is reviewed to determine levels of resection of the femur and tibia in order to:



    • Achieve a sound oncologic margin


    • Account for a projected center of rotation of the rotated tibiotalar joint to be at the same level of the nonoperative knee when the patient reaches skeletal maturity


Positioning



  • The patient is placed supine on a radiolucent table.


  • The entire lower extremity from the pelvis to the foot must be prepped and draped.


  • This setup provides vascular access and enables internal fixation to the level of the hip joint if needed.


  • Intraoperative fluoroscopy is recommended in order to aid placement of hardware.


Approach



  • The skin incision must be planned to accommodate the disproportion between thigh and calf circumference.


  • Circumferential incisions are commonly made at acute angles to each other to account for this thigh/calf discrepancy (FIG 2).


  • A longitudinal incision is then drawn to connect the proximal and distal circumferential flaps. This line is placed ideally to expose a plane for tumor resection and neurovascular dissection.3,4,5,6






FIG 2 • Intraoperative outline of incision in the right lower extremity of a pediatric patient with a distal femur osteosarcoma.

Feb 27, 2020 | Posted by in Pediatric plastic surgery | Comments Off on Rotationplasty of the Lower Extremity
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