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An 11-year-old girl with a 3-year history of right ankle pain
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The patient is a healthy 11-year-old, girl with chronic, right, posterolateral ankle pain. She has been able to “pop” the tendons on the outside of both ankles for 3 years. She describes the pain as sharp and throbbing which is intermittent in frequency and associated with tightness. She describes moderate relief with lace-up ankle braces and NSAIDs. The pain worsens with any prolonged physical activity. In the past, she had multiple mild ankle injuries as a cheerleader and softball player.
On exam, the patient walks normally. The patient can actively dislocate her peroneal tendons resulting in her tendons being palpable lateral to the lateral malleolus during active dorsiflexion. Otherwise, the patient is neurovascularly intact with full strength in all directions. Radiographs were normal demonstrating open physes without acute fractures/dislocations/coalitions.
Source: Kamran S. Hamid, MD, MPH
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Bilateral peroneal tendon dislocations in a skeletally immature female
The patient’s clinical examination is consistent with bilateral dislocations of the peroneal tendons with pain worse on the right side than the left side. An MRI was obtained to assess the peroneal tendons and was found to be negative for intrasubstance pathology. The patient had undergone periods of rest and immobilization for the right ankle pain with minimal to no relief. Additionally, she had been advised by multiple orthopedic surgeons to consider peroneal tendon groove deepening after reaching skeletal maturity. Kocher and colleagues described a physeal-sparing stabilization technique requiring peroneal tendon rerouting deep to the calcaneofibular ligament (CFL). This procedure was offered to the patient and her mother. After engaging in the shared-decision making process, the patient and her mother decided to proceed with operative intervention.
Surgical technique
The patient was placed in the lateral decubitus position and a deflated bean bag with well-padded prominences was used. A lead apron was placed circumferentially on the patient to protect her reproductive organs from radiation. A thigh tourniquet was placed, and the right lower extremity was draped and prepped in standard sterile fashion.
A 15-blade scalpel was used to create a curvilinear incision posterior to the distal fibula. In layers, the dissecting scissors were used to spread and identify the lateral calcaneal branch of the sural nerve. This was retracted and protected. The plane of the superficial peroneal retinaculum (SPR) was identified bluntly with a sponge. This revealed the dislocating peroneal tendons. The retinaculum was incised after which both tendons became frankly dislocated. The tendons were debrided of a low-lying muscle belly and soft tissue (Figure 3). The CFL was identified and sharply excised from the distal fibula. The anterior aspect of the CFL was dissected from the anterior talofibular ligament. The peroneal tendons were mobilized deep to the CFL (Figure 4, page 29). A 0.045-mm K-wire was marked at 8 mm and placed into the distal fibula using fluoroscopy to confirm its placement was outside the physis (Figure 5, page 29). With the ankle in neutral dorsiflexion, an 8-mm bioresorbable SonicAnchor (Stryker) was placed in the same track as the K-wire and was used to suture the CFL to the distal fibula (Figure 6). The periosteum and SPR were repaired using 2-0 Vicryl (Ethicon).
The ankle went through the range of motion with careful assessment of the peroneal tendons, which confirmed no dislocation of the peroneal tendons. In addition, a probe placed deep to the peroneal tendons was unable to manually dislocate them. The wound was closed and the patient was placed into a short leg splint with the foot in neutral dorsiflexion and slight inversion with instructions to be non-weight-bearing.
Postoperatively, the patient’s wound was checked at 1 week and the patient was given instructions to continue her non-weight-bearing restriction. At 3 weeks, the patient’s pain significantly improved. At this time, the patient was allowed to begin walking in a CAM boot and initiate physical therapy. At 6 weeks, the patient reported continued improvement of pain in the right ankle and transitioned into a lace-up ankle brace. At 9 weeks, the patient was progressing well with physical therapy and was pain-free in the right ankle. She had no further sensations of peroneal dislocation or subluxation. At this time, the patient was allowed to progress with physical activities as tolerated. Of note, 3 months after surgery, she developed plantar midfoot pain that did not resolve with immobilization and further therapy. A repeat MRI demonstrated reduction of her peroneal tendons and evidence of peroneus longus tendinitis. (Figures 7a and 7b). After 2 months of additional conservative management, she was prescribed a short oral steroid taper and her symptoms completely resolved. At 1-year follow-up, she had a VAS score of 0/10 and was able to participate fully in activities with no right ankle pain.
Discussion
The peroneal tendons travel along the posterior aspect of the lateral malleolus bordered by the posterior talofibular ligament, SPR, CFL and inferior peroneal retinaculum (IPR). The CFL is located deep to the peroneal tendons while the PTFL, SPR and the IPR are superficial. Of these, the SPR is most responsible for preventing subluxation of the peroneal tendons. As such, disruption of the SPR, fracture along the margins of the lateral malleolus or a relatively shallow peroneal groove may contribute to subluxation or frank dislocation of the peroneal tendons with dorsiflexion and eversion of the ankle.
Clinically, patients describe pain in the lateral ankle that may often be attributed to an ankle sprain. However, patients with peroneal instability often also develop noticeable subluxation or dislocation of the peroneal tendons in resisted dorsiflexion at the ankle joint. For these patients, the mainstay of initial treatment should include rest, immobilization and symptomatic treatment with NSAIDs. However, peroneal instability recalcitrant to conservative treatment may require surgical management.
Operative treatment for peroneal subluxation aims to recreate the anatomic constraint for the peroneal tendons. Modalities used in adults include deepening of the peroneal groove; repair, reattachment or reinforcement of the SPR; and bony procedures to create a new constraint. Pediatric patients present a unique challenge in that the physis must be avoided to minimize the risk of distal fibular growth disturbance. This limits how transferable the modalities commonly used in adults are to the pediatric population.
For this patient, the peroneal tendons were rerouted deep to the CFL while preserving the distal fibular physis. The CFL was fixed to the fibula using a suture anchor. This procedure was originally described in a series of seven pediatric patients by Kocher and colleagues. In their series, the patients had no recurrent subluxation or dislocations and all patients returned to sport. The authors reported postoperative stiffness due to possible over-restraint of the CFL. This may be the most significant disadvantage to the procedure. For this, they recommend aggressive physical therapy to assure normal range of motion at the ankle joint.
The case presented here supports the use of physeal-sparing rerouting of the peroneal tendons under the CFL. For pediatric patients with recurrent dislocation, this procedure offers an alternative to waiting until skeletal maturity to undergo an adult procedure (fibular groove deepening, etc.). Further investigation is warranted to better understand management of this rare entity when it occurs in the pediatric population.
- References:
- Boykin RE, et al. J Pediatr Orthop. 2010;doi:10.1097/BPO.0b013e3181fbfcea.
- Martens MA, et al. Am J Sports Med. 1986; doi:10.1177/036354658601400210.
- Philbin TM, et al. J Am Acad Orthop Surg. 2009;17:306-317.
- Sarmiento A, et al. J Bone Joint Surg Am. 1975;57:115-116.
- For more information:
- Junyoung Jon Ahn, MD; Daniel D. Bohl, MD, MP; and Kamran S. Hamid, MD, MPH, can be reached at Rush University Medical Center, Department of Orthopaedic Surgery, 1611 W. Harrison St., Suite 300, Chicago, IL 60603; Ahn’s email is jon.ahn.tx@gmail.com. Bohl’s email is danielbohl@gmail.com. Hamid’s email is kamran.hamid@rushortho.com.
Disclosures: Ahn, Bohl and Hamid report no relevant financial disclosures.