61-year-old man with ankle swelling and inability to dorsiflex his foot
Click Here to Manage Email Alerts
A 61-year-old man presented to clinic 1 week after a motor vehicle accident with left ankle pain and swelling. He also reported having a chronic inability to dorsiflex his left foot.
He said he sustained a penetrating insult to the lower limb in 1986 that left him immediately unable to raise his foot. He had been given an ankle foot orthosis (AFO) and attempted physical therapy, but he no longer had any dorsiflexion capability past neutral. The patient is able to ambulate with a steppage gait, but he describes his overall ambulation as labored and difficult. He is an everyday smoker. He had no other significant past medical history. He is unemployed but remains active and weight-bearing on a daily basis, walking and doing other activities, as well as driving.
Examination was notable for mild swelling about the ankle with a supple foot, as well as two well-healed scars about the anterior and posterolateral leg just distal to the knee consistent with a history of ballistic insult. His foot was resting in neutral position and unable to be passively or actively dorsiflexed past 0°. The Silfverskiold test was negative. Sensation was intact to the saphenous and sural nerves, while absent from the deep and superficial peroneal nerve distributions. The patient was unable to bear weight on the affected extremity, and thus ambulation was not tested. Ligamentous stability, heel rise and special testing about the ankle were also deferred due to the significant pain and swelling.
What is your diagnosis?
See answer below.
Bimalleolar ankle fracture to the left lower extremity
Plain films revealed a bimalleolar ankle fracture to the left lower extremity (Figure 1). The clinical exam is consistent with a foot drop secondary to penetrating trauma to the common peroneal nerve. Additional workup for infection was negative, and laboratory values including a complete blood count, basic metabolic panel and prothrombin time/international normalized ratio were within normal limits. Of note, secondary to the patient’s clinical exam and the chronicity of the penetrating trauma, electrodiagnostic studies were deferred.
Important Findings
Source: Ian Savage-Elliott, MD
The presence of a fully functioning posterior tibial tendon (PTT) impacts treatment options. Weakness of inversion, plantarflexion, forefoot abduction, forefoot varus, hindfoot valgus, and a loss of the medial arch vs. the contralateral side are important examination maneuvers to rule out PTT insufficiency. Sensory loss to the bottom of the foot in conjunction with a power score of less than 4/5 for the PTT may imply a concomitant tibial nerve injury.
It is necessary to determine whether the deformity of the foot is fixed or flexible, as this may have implications for the use of only tendon transfers vs. the necessity of osteotomy or arthrodesis. Finally, in thinking about the etiology of the drop foot, it is important to examine for traumatic vs. congenital causes, as this has implications for the patient’s outcome with surgical intervention. Additionally, syndesmotic ossification from trauma can make transfer through the interosseous membrane extremely difficult, and therefore a thorough history of injuries to the ipsilateral extremity is paramount.
Treatment options?
Options for the foot drop include continued nonoperative management, which has been limiting our patient’s mobility significantly. Given the patient required operative management for his ankle fracture and his deformity was flexible, the decision was made to proceed with tendon transfer vs. an osteotomy or arthrodesis. While numerous tendon transfers can be used to improve dorsiflexion, including a PTT transfer, a combined PTT to anterior tibialis, and flexor digitorum longus to extensor halluces longus and extensor halluces longus, the most common tendon transfer used for common peroneal nerve injury is the Bridle procedure. This dynamic tendon transfer involves the anastomosis of the PTT with the tibialis anterior (TA) and peroneus longus (PL), and transfer of this anastomotic weave to the middle cuneiform for bony fixation. The advantages of the Bridle include the three points of attachment for the tendon while it also acts to stabilize the lateral ankle. Given the ability to use the lateral incision for both harvesting the PL and fixing the lateral malleolus, we opted for a combined procedure instead of staging our treatment plan.
Operative technique
The patient was positioned supine on a ramp of blankets. Our first step was to lengthen the Achilles tendon via a triple-cut percutaneous lengthening, which allowed our patient to gain about 20° dorsiflexion. Next, attention was turned towards harvesting the PTT off of the most distal aspect of its tarsal-navicular insertion. Once the tendon was harvested, a second incision was made along the lateral leg through which the tendon was retrieved above the extensor retinaculum. It was then passed through the interosseous membrane from the posterior to the anterior compartment (Figure 2) and simultaneously weaved through a longitudinal split in the tibialis anterior.
Next, an incision was made laterally along the posterior aspect of the fibula. Through this incision we were able to visualize both the fracture and the peroneus longus. The bone was osteoporotic, which was consistent with a lack of normal usage. The fracture was noted to be comminuted and thus was bridged using a periarticular locking plate. The PL was harvested and a tenodesis to the peroneus brevis was performed proximally (Figure 4). The distal aspect of the tendon was then transferred subcutaneously from the lateral to the anterior compartment. At this point, we completed fracture fixation of the medial malleolus using two percutaneous screws.
Next, we anastomosed the three tendons using suture and whip-stitched the tendon anastomoses. (Figure 5). Under fluoroscopic guidance, we drilled the suture passing pin into the middle cuneiform. Next, we reamed over the Keith needle. We threaded the suture through the needle and delivered it through the middle cuneiform, passing the tri-woven tendon anastomosis superficial to the extensor retinaculum and attached it to the medial cuneiform via interference screw fixation. (Figure 6).
The anastomosis was then tensioned with the foot in neutral. At the conclusion of the procedure, the patient sat in neutral alignment (Figure 7, page 22). Closure with subcutaneous sutures and staples, and then splinting in neutral, completed the procedure. Postoperative radiographs showed improved alignment about the fracture sites (Figure 8).
Our postoperative protocol includes splinting the patient in neutral with the splint taken off at 2 weeks. Active plantarflexion is restricted for 8 weeks and an AFO is used to maintain dorsiflexion during the healing process.
At 6-week, The fracture was healing well and the patient was able to maintain neutral dorsiflexion at rest. He was ready to begin physical therapy.
Discussion
Common peroneal nerve palsy has been reported as the most frequent lower extremity palsy. While favorable function can be obtained in most traumatic causes via neurolysis or nerve repair with suturing or graft, gunshot wound injuries portend a worse outcome, and exploration is commonly delayed until 3 months and only completed if there is no significant functional recovery. When nerve repair is no longer feasible due to a delayed presentation or an inability to complete nerve repair, as was the case with our patient, tendon transfer in the flexible foot and osteotomy or fusion in the foot with fixed deformity are the most reliable treatment options. The goals of these treatments are not for perfect function, but rather restoration of the plantigrade foot by replacing deficits and allowing for functional ambulation without bracing.
While previously proposed by M.B. Watkins, Alessandro Codivilla and Vittorio Putti in their transfer of the PTT to the dorsum of the foot, Daniel C. Riordan, MD, and Richard A. Brand Jr., MD, of New Orleans were some of the first physicians to popularize the Bridle modification of this tendon transfer. The former, a hand surgeon by training with vast experience in tendon transfers for World War II combatants, ultimately published his results for the procedure in 107 pediatric patients with 80% good to excellent clinical results. More than 75% of the patients were brace-free at a mean 5.75-year follow-up. The procedure was then modified by Raoul Rodriguez, MD, of Tulane University to include PTT fixation to the middle cuneiform via an interference screw, thus bringing the lever arm to the center of the midfoot and changing the bony fixation. Rodriguez performed the procedure in 11 feet and noted they all were brace-free at 6.68 years follow-up (range 6 months to 13 years). The largest recent case series on the Bridle technique in adults was published by J.E. Johnson and colleagues with 19 patients treated with the Bridle technique for foot drop vs. 10 controls. While these researchers noted reduced dorsiflexion and plantarflexion strength using Biodex scanning and reduced clinical outcome scores vs. the controls, all patients reported excellent to good subjective outcomes and stated they would want the procedure repeated. Many of the patients who were athletes also returned to sport. Furthermore, no patient wore an AFO for everyday activity. There was no notable deficiency in foot alignment secondary to the removal of the tibialis posterior from its native positioning at 2-year follow-up on radiographic examination.
Impaired dorsiflexion
It is expected that patients will lose at least one grade of muscle power with most tendon transfers, particularly those that are aphasic, such as the transfer of the PTT to the dorsum of the foot. While the Bridle anastomosis of the PL and TA to the PTT should help balance the eversion and inversion of the foot, impaired dorsiflexion strength is expected. The ability to function brace-free, as well as maintain a stable ankle after bimalleolar fracture fixation, are the desired outcomes.
While dynamic tendon transfers remain the gold standard for maximizing function in the patient with drop foot, the rates of concomitant nerve exploration with tendon procedures have not shown any improved outcome. John R. Prahinski, MD, and colleagues looked at the Bridle procedure in 10 military patients with traumatic peroneal nerve injuries, with surgery performed at 1 year to 3 years following injury. Nine of 10 patients were brace-free and three patients returned to active duty at 61 months mean follow-up. In the subset of five patients who underwent concomitant nerve exploration and repair or neurolysis, electromyography showed little if any nerve function return in all five patients. Thus, these authors concluded that nerve exploration after 1 year offers little benefit in the traumatic common peroneal nerve injury patient.
We believe this is the first case of the tendon transfer being done in combination with fracture fixation. Potential benefits of this include tendon healing of the anastomoses (particularly the PL to PB) which may be augmented by mesenchymal stem cells from the blood associated with fracture fixation. Possible negative effects of concomitant Bridle and fracture fixation could be a delay in passive range of motion secondary to increased pain, and the necessity of longer operative time. However, based on this patient’s early results, we believe a combined procedure is feasible.
In summary, the Bridle procedure is optimally suited for restoring brace-free ambulation in both traumatic and congenital foot drop. Key pearls of the procedure include appropriate harvesting of the tendons, transfer through the interosseous membrane and bony fixation to the dorsum of the foot. We believe this can also be done in combination with fracture fixation, with only the use of two additional percutaneous, poke hole incisions to the medial malleolus. Although patient expectations must be managed and completely normal function is not expected, this is a reliable procedure for restoring motion to those who have had an otherwise devastating injury.
- References:
- Dy C, et al. The troublesome triad: Knee trauma, peroneal nerve injuries and foot drop – The team approach. AOFAS, ASSH, AOSSM sponsored webinar. May 20, 2020. http://prc.aofas.org/URL?TRIAD0520. Accessed: July 14, 2020.
- Johnson JE, et al. Foot Ankle Int. 2015;doi:10.1177/1071100715593146.
- Kim DH, et al. Neurosurgery. 2004;doi:10.1227/01.neu.0000124752.40412.03.
- McCall RE, et al. J Pediatr Orthop. 1991;11:83–89.
- Mont Ma, et al. J Bone Joint Surg Am. 1996;78:863-869.
- Prahinski JR, et al. Foot Ankle Int. 1996;doi:10.1177/107110079601701005.
- Richardson DR, et al. Foot Ankle Clin N Am. 2011;doi:10.1016/j.fcl.2011.06.003.
- Rodriguez R, et al. Foot Ankle. 1992;doi:10.1177/107110079201300203.
- Ryssman DB, et al. Ankle Clin N Am. 2011;doi:10.1016/j.fcl.2011.08.001.
- Vigasio A, et al. Clin Orthop Relat Res. 2008;doi:10.1007/s11999-008-0249-9.
- For more information:
- Travis R. Flick, MD, is a research fellow; Ramon F. Rodriguez, MD, is chief of the foot and ankle department and assistant professor of orthopedics; and Ian Savage-Elliott, MD, is a chief resident in the department of orthopedic surgery at Tulane University Medical Center. They can be reached at 1415 Tulane Ave., New Orleans, LA 70112. Flick’s email: tflick@tulane.edu. Rodriguez’s email: rrodri1@tulane.edu. Savage-Elliott’s email: iansavageelliott@gmail.com.
- Edited by Travis Frantz, MD, and Ian Savage-Elliott, MD. Frantz is a sports medicine and shoulder fellow at TRIA Orthopaedic Center in Minneapolis. He completed his orthopedic surgery residency at The Ohio State University Wexner Medical Center in Columbus, Ohio. Savage-Elliott is a chief resident in the department of orthopedic surgery at Tulane University Medical Center in New Orleans. He will pursue fellowship training in foot and ankle and sports medicine following residency completion. For information on submitting Orthopedics Today Grand Rounds cases, please email: orthopedics@healio.com.
Collapse
Read more about
Click Here to Manage Email Alerts