Journal of Plastic, Reconstructive & Aesthetic Surgery
Adductor magnus muscle transfer to restore knee extension: Anatomical studies and clinical applications
Introduction
Loss of knee extension is a devastating condition that produces significant disability, including the inability to run, climb stairs, drive, and even ambulate without supportive aids. Most cases are iatrogenic in nature, but traumatic and malignant causes are possible.1, 2, 3
Reconstructive options after loss of quadriceps function are poorly described despite its disabling impact.4,5 Nerve grafting is widely used, but the proximal stump can be difficult to identify and access.6 Our group7 and others8, 9, 10 have pioneered nerve transfers from the obturator to the femoral nerve in order to restore function. However, many patients present after terminal atrophy of the target muscle sets in or with injury or pathology involving the quadriceps muscles, precluding nerve transfers. More aggressive options including free functional flaps have been described, but are not tolerated by all.11, 12, 13, 14
In patients who are not appropriate candidates for nerve-based or microvascular reconstruction, pedicled muscle transfers remain an option. These have been performed for decades in the upper extremity with excellent results,15, 16, 17 though they have not been as well-described in the lower extremity. Optimally, the donors are expendable and synergistic with the recipient, as the donor performs one function along a straight line of pull.18 The donor also needs strength and excursion to match the desired motion, which limits lower extremity reconstruction due to the large biomechanical demand on donors as compared to the upper extremity.
Previous attempts at using muscle transfers in the lower extremity have focused on the plantarflexion at the Achilles tendon19, 20, 21, 22, 23 and providing support to an intact quadriceps with knee flexors, not restoring knee extension.24,25 Previous attempts at restoring knee extension used knee flexors and required extensive transposition and training antagonistic muscles with a spiral line of pull, leading to suboptimal results.26
We propose adductor magnus as a potentially more appropriate donor for knee extension. Given its location and function, it is synergistic with the quadriceps and requires less dissection and transposition while providing a straighter line of pull than a hamstring donor. Further, it remains functional in an isolated femoral nerve palsy as its innervation is from the obturator nerve. Its relatively larger size compared with other described options, such as gracilis or sartorius,*** and expendable function suggests that it may better handle the large load required to replacing quadriceps function without downgrading hip adduction, making it a more ideal donor either alone or in combination with other muscles.
We describe the adductor magnus as a muscle transfer to restore knee extension in patients with femoral nerve palsy that are too late for nerve-based reconstruction, in addition to other muscle donors, such as the gracilis, sartorius, or tensor fascia latae (TFL), to maximize stabilization and strength. We detail the anatomic considerations of this transfer and report the results of three patients who have undergone this procedure.
Section snippets
Anatomic study of the adductor magnus
Anatomy of the adductor magnus, including external landmarks, orientation and structure of the vascular pedicle, the length of available tendon for weave, the proximal musculotendinous junction, location of the adductor hiatus, and relationship of the tendinous insertion to external landmarks was dissected in nine limbs.
The adductor magnus is not palpable on the medial aspect of the thigh, but its tendon travels posterior to the palpable adductor longus across all studied limbs. The distal
Surgical technique
With the patient supine, the posterior border of the adductor longus was marked from the palpable femoral pulse to the medial aspect of the knee, with the most distal incision curved anteriorly to allow exposure of the patellar tendon (Figure 4). The gracilis and sartorius are easily identified and retracted laterally and medially, respectively, and next the adductor magnus identified between, crossing underneath the sartorius distally (Figure 5).
The adductor magnus insertion is then located at
Post-operative rehabilitation protocol
Patients were discharged as non-weightbearing with a knee immobilizer fixing the joint in extension for a minimum of 6 weeks. Ambulation during this time was accomplished with a walker or crutches. Patients were transitioned to full weightbearing around 6–8 weeks after surgery while still braced in extension.
At 8 weeks post-operatively, physical therapy was started with a focus on motor re-education and antigravity exercises for all actions in the thigh, including hip motion, knee extension,
Patient 1
A 52-year-old woman presented with failure to extend her right knee 1 year after a right total hip replacement, and frequent falls due to her instability and weakness. She had no return of function, with Medical Research Council (MRC) 0/5 strength, numbness in the femoral nerve distribution, consistent with an isolated femoral nerve palsy and intact obturator nerve function.
Given the time since injury, she was not a candidate for nerve transfers as terminal atrophy of the quadricep muscles had
Discussion
In nerve injuries, nerve-based reconstruction is not feasible, if terminal atrophy of the target muscle and its neuromuscular junction has occurred.30 There may be involvement of the quadriceps muscles due to injury or resection of malignancy. In these scenarios, muscle transfers remain the only means to restore function, taking expendable, functional donors, and transferring their tendons to perform lost function. In line with the tenants of tendon transfer in the upper extremity, these are
Conclusions
Loss of knee extension profoundly affects the quality of life of patients. We propose the adductor magnus muscle transfer as a new reconstructive option to reconstruct quadriceps function in patients with femoral nerve palsy outside the window for nerve-based reconstruction. Further, the adductor magnus muscle transfer remains a possibility to augment function in those who have undergone nerve-based reconstruction with suboptimal results or requiring more power. Our findings are supported by
Declaration of Competing Interest
None.
Ethical Approval
N/A
Funding
None.
References (35)
- et al.
Transfer of the anterior branch of the obturator nerve for femoral nerve reconstruction and preservation of motor function: a case report
Int. J Surg Case Rep
(2018) - et al.
Free functional rectus femoris muscle transfer for restoration of knee extension and defect coverage after trauma
J. Plast. Recon. Aesth. Surg.
(2006) - et al.
Transfer of latissimus dorsi muscle for the functional reconstruction of quadriceps femoris muscle following oncological resection of sarcoma in the thigh
J. Plast. Recon. Aesth. Surg.
(2011) - et al.
Short-Term results of flexor hallucis longus transfer in delayed and neglected Achilles tendon repair
J Foot Ankle Surg
(2018) - et al.
Reconstruction of the medial patellofemoral ligament using the adductor magnus tendon
Arthrosc. Tech.
(2017) - et al.
Nerve transfers: new options for reconstruction following nerve injury
Hand Clin
(1999) Immediate active mobilization versus immobilization for opposition tendon transfer in the hand
J. Hand Surg.
(2006)Immediate active mobilization versus immobilization following tendon transfer for claw deformity correction in the hand
J. Hand Surg.
(2008)- et al.
J. Hand Surg
(2010) - et al.
Intrapelvic and thigh level femoral nerve lesions: management and outcomes in 119 surgically treated cases
J Neurosurg
(2004)
Femoral neuropathy following direct anterior total hip arthroplasty: an anatomic review and case series
J Surg Case Rep
Iatrogenic femoral nerve injury: a systematic review
Surg Radiol Anat
Predictors of functional outcomes following limb salvage surgery for lower-extremity soft tissue sarcoma
J Surg Oncol
Complete femoral nerve resection with soft tissue sarcoma: functional outcomes
Ann Surg Oncol
Sural nerve grafting for long defects of the femoral nerve after resection of a retroperitoneal tumour
J Bone Joint Surg Br
Obturator nerve transfer for femoral nerve reconstruction: anatomic study and clinical application
Plast. Recon. Surg.
Transfer of the two motor branches of the anterior obturator nerve to the motor portion of the femoral nerve: an anatomical feasibility study
Microsurg
Cited by (0)
Presented at: Plastic Surgery the Meeting (ASPS) 2019 in San Diego, California on September 22, 2019. Awarded Best Reconstructive Paper in Session.
This study conforms to the Declaration of Helsinki. This study was performed according to the STROBE guidelines for patient series.