Skeletally Immature Athletes Ununited Osteochondral Fractures of the Distal Fibula

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Chronic, Painful Ankle Instability in Skeletally Immature Athletes Ununited Osteochondral Fractures of the Distal Fibula Brian D. Busconi,* MD, and Arthur M.

1 Chronic, Painful Ankle Instability in Skeletally Immature Athletes Ununited Osteochondral Fractures of the Distal Fibula Brian D. Busconi,* MD, and Arthur M. Pappas, MD From the Department of Orthopedics and Physical Rehabilitation, University of Massachusetts Medical Center, Worcester, Massachusetts ABSTRACT We report 10 cases of chronic, painful ankle instability in skeletally immature athletes associated with ununited osteochondral fragments of the distal fibula. All the patients experienced multiple inversion injuries with recurrent pain and instability that failed to improve after a supervised exercise and rehabilitation program. Osteochondral fragments of the distal fibula were visible on all standard radiographs of the affected ankles. Treatment consisted of operative excision of the bony fragment and an anatomic nonaugmented repair of the lateral ligament complex and capsule. All 10 patients were available for long-term followup an average of 6.5 years (±2) after surgery; all ankles improved functionally, with no recurrences of instability. * Address correspondence and reprnt requests to Bnan D Busconi, MD, Department of Orthopedics and Physical Rehabilitahon, University of Massachusetts Medical Center, 55 Lake Avenue North, Worcester, MA No author or related institution has received any financial benefit from research in this study. Trauma to the lateral ligamentous complex of the ankle is a common sports injury. Epidemiologic studies indicate that ankle sprains occur with the highest frequency in athletes aged 15 to 35 years, with a peak incidence in persons aged 15 to 19.1>4,5,1~~14 The majority of the literature describes adult patients with lateral ligamentous ankle injuries. 2,10 There is little recognition of injuries among skeletally immature athletes.4,19 The prime objective of this article is to state that a severe lateral ankle injury in this group of skeletally immature athletes may result in an avulsion of the anterior talofibular ligamentous complex with a chondral or an osteochondral fragment. This avulsion fracture may proceed to nonunion thereby causing chronic mechanical and functional instability. If traditional treatment and rehabilitation of this injury fails, we recommend surgical excision of the fragment and repair of the lateral ligaments and capsular complex. MATERIALS AND METHODS From 1981 to 1991, we evaluated 60 skeletally immature children for chronic ankle pain and instability. Among these children, 50 responded well to a 4-month (±2) supervised nonoperative rehabilitative program, and 10 continued to have symptoms. There were six girls and four boys who had a mean age of 13 years (±3, SD; range, 10 to 17). All the patients reported that their initial traumatic event happened during sports participation. All the patients reported distal anteromedial fibular pain, recurrent swelling, a feeling of &dquo;giving way,&dquo; and recurrent sprains of the lateral ligament complex of the ankle that adversely affected their ability to participate in sports. The diagnosis of chronic ankle instability was further confirmed by physical examination of both ankles. Active and passive ranges of motion were recorded. Manual motor tests were performed on the extensors, dorsiflexors, evertors, invertors, and plantar flexors of the foot and ankle. The anterior and posterior talofibular, calcaneofibular, anterior distal tibiofibular, and anterior deltoid ligamentous complexes were palpated and evaluated for pain and stability. The stability of both ankles was evaluated by anterior drawer and talar tilt tests and then the results were compared. All 10 patients experienced increased pain when the examining physician palpated the distal anteromedial aspect of the fibula. All the patients had AP, lateral, and mortise radiographic views taken of the affected and unaffected ankles. The preoperative radiographs revealed an osteochondral fragment adjacent to the anteromedial distal fibula in all the patients (Fig. 1). In three of our skeletally immature athletes, original radiographs of the affected ankles showed no sign of osseous injuries; however, physical examination findings were consistent with damage to the 647

648 Figure 1. An AP radiograph of a skeletally immature athlete with a ununited osteochondral fragment. anterior talofibular ligament complex (Fig. 2).

$Injury to soft tissues, congenital bony variants, and fractures that may mimic chronic lateral ankle instability in growing children were excluded by examining for tendon subluxations or dislocations$

2 648 Figure 1. An AP radiograph of a skeletally immature athlete with a ununited osteochondral fragment. anterior talofibular ligament complex (Fig. 2). As the children continued their normal sequential development of ossification, later follow-up radiographs did eventually confirm osteochondral fragments (average, 2 months) (Fig. 3). Injury to soft tissues, congenital bony variants, and fractures that may mimic chronic lateral ankle instability in growing children were excluded by examining for tendon subluxations or dislocations (peroneal and posterior tibial), subtalar stiffness (talocalcaneal, calcaneonavicular, and calcaneocuboid coalitions), or bony pain along the fibular shaft, fibular physis, talar body, talar osteochondral surface, and fifth metatarsal base and shaft. Tarsal coalitions and fractures were further excluded with AP, lateral, and 45 oblique views of the foot. Operative Technique A curvilinear incision was made along the anterior border of the distal fibula, terminating at the level of the peroneal tendons. The dissection was carried down to the level of the ligaments and the joint capsule along the anterior border of the lateral malleolus. 3,6,8 The joint capsule was dissected to preserve the extensor retinaculum. The capsule was then divided and the anterior talofibular ligament was identified. In all patients, there was evidence of scarring of the anterior talofibular ligamentous bundle and capsule. These structures were incised as one unit instead of being individually dissected. Once the anterior talofibular ligament and capsule were opened, the osteochondral fragment of the fibula was located. The fragment was found on the anteromedial aspect of the fibula and slight motion occurred between this fragment and the distal end of the fibula when stressed with a probe. There was evidence of nonunion with granulation and inflamed Figure 2. Anteroposterior (A) and lateral (B) radiographs of a skeletally immature athlete after an acute ankle inversion injury without evidence of skeletal injury. synovial tissues between this fragment and the distal end of the fibula in all the patients. The fragment sizes in

649 no patients were any degenerative changes noted between the fibula and the talus, nor were there any changes to the talar body, to the articular surfaces of the dome of the talus, or to the tibia.

3 649 no patients were any degenerative changes noted between the fibula and the talus, nor were there any changes to the talar body, to the articular surfaces of the dome of the talus, or to the tibia. Using 2-0 absorbable sutures, the capsule and anterior talofibular ligaments were sutured into fibular drill holes and reinforced in pants-over-vest fashion. Once the repair was completed, the ankle was evaluated for stability and range of motion. The previously identified lateral extensor retinaculum was replaced over the repair site and sutured to achieve added support. After these repairs, a layered closure was performed with an absorbable, subcutaneous suture. A short leg cast was applied to maintain the ankle in 5 of eversion and 5 of plantar flexion. The cast was bivalved after 4 weeks and passive- and active-assisted range of motions, under the direction of a physical therapist, were initiated. At the end of 6 weeks, the cast was removed and the ankle was placed in an external support. At this point, rehabilitation consisted of a therapeutic exercise program that returned full ankle and subtalar motion. Once motion was obtained, progressive muscle strengthening (especially peroneal and dorsiflexion) and reestablishment of motor coordination through proprioceptive exercises were instituted. The complete rehabilitation and return-to-sports period in our 10- to 17-year-old population averaged 12.5 ± 2 weeks. Patients were required to use an external support during high-risk activities for at least 6 months after surgery. The goals of rehabilitation were to decrease swelling and pain, to limit both functional and mechanical instability, and to restore full range of motion. Histology Surgical specimens from seven patients were examined histologically. Fragments ranged from sizes of 4 by 2 by 0.7 mm to 10 by 4 by 2 mm. Histologic analyses showed fragments with a necrotic edge empty of osteocytes in lacunae with chronic fibrous granulation tissue consistent with a fracture fragment. (Fig. 4) RESULTS Figure 3. Anteroposterior (A) and lateral (B) radiographs 2 years after injury in the same patient seen in Figure 2. Notice the ossification of an avulsed (chondral) fragment. these patients ranged from 4 by 2 by 0.7 mm to 10 by 4 by 2 mm. The ankle joint was subsequently examined and in All 10 patients were available for long-term follow-up examination (range, 48 to 90 months). All the patients reported no ankle pain during vigorous athletic competition. No patient sustained an inversion injury on the operated ankle after surgery. All the patients reported no functional limitations after reconstruction. On physical examination, no patient reported pain during palpation of the distal anterolateral joint capsule. Averages of dorsiflexion, plantar flexion, and inversion were obtained with a goniometer, and measurements were compared with those of the unoperated ankle. The average dorsiflexion was 17, compared with 20 on the unoperated side. The average plantar flexion was 43, versus 47 on the unoperated ankle. Inversion with the ankle in plantar flexion was 90% of the unoperated side (range,

$650 Figure 4. Histologic analyses showed fragments with a necrotic edge empty of osteocytes in lacunae with chronic fibrous granulation tissue consistent with an ununited fracture fragment.$ DISCUSSION The secondary ossification center of the distal fibula develops between the 2nd and 3rd years of life (range, 6 months to 3 years).

DISCUSSION The secondary ossification center of the distal fibula develops between the 2nd and 3rd years of life (range, 6 months to 3 years).

4 650 Figure 4. Histologic analyses showed fragments with a necrotic edge empty of osteocytes in lacunae with chronic fibrous granulation tissue consistent with an ununited fracture fragment. 75% to 95%) with the ankle in internal dorsiflexion or plantar flexion. DISCUSSION The secondary ossification center of the distal fibula develops between the 2nd and 3rd years of life (range, 6 months to 3 years). Fibular physeal growth and ossification ultimately complete the formation of the lateral malleolus, and physiologic epiphyseodesis (i.e., normal developmental closure of the epiphysis) to the metaphysis occurs by 12 to 14 years in girls and by 15 to 18 in boys. 13,15,16 During the late stages of ossification of the distal fibula, an inversion injury can result in avulsion of the ligament along with an associated cartilaginous attachment. This is a peripheral physeal avulsion fracture. The fracture is usually located at the anteromedial periphery of the malleolus where the anterior talofibular ligament is attached. In some skeletally immature patients, physical examination findings indicate an avulsion injury; yet, radiographs show no evidence of an osseous avulsion fragment (Fig. 2). This cartilaginous avulsion fracture should also be treated with cast immobilization. If this injury is not recognized, it may develop and enlarge as an unattached fragment that contributes to both instability and pain of the lateral ligamentous complex because the anterior talofibular ligament lacks a fibular anchor (Fig. 3). Some authors have associated ankle pain with an accessory ossicle or separate center of ossification. 7,9,12,13,17 The os subfibulare and patterns of ossification have been well-discussed by Ogden and Lee.15 Powell,18 in 1961, found a separate center of ossification for the lateral malleolus in 1% of his patients and for the medial malleolus in 20% of his patients. Hoed,~ in a study of 150 healthy children, found 21 ankles with separate medial or lateral centers of ossification. Often these developmental ossifications are seen at an earlier age. Developmental ossifications are associated with local discomfort and occasional swelling, but they are infrequently associated with the symptoms of instability. In 1984, Vahvanen et al.19 studied acute lateral ligamentous injuries of ankles in children. Among the 40 ankles that were operated on, 50% of the patients had some kind of cartilaginous or bony fragments or both that were acute injuries. Griffiths and Menelaus, Karlsson and Lansinger,l2 and Paterson and Benjamin ~~ have reported ossification areas associated with ankle instability. In our study population, all the patients had osteochondral or chondral fractures. They were not secondary to anomalous developmental events. The fractures arose from traumas that disrupted the ligamentous attachment with a cartilaginous bone fragment. This created an area of mechanical instability that caused the patient to experience multiple recurring inversion injuries. When nonoperative measures were not successful, these patients then underwent surgical exploration, excision of the osteochondral fragment, freshening of the base of the fibula, and reattachment of the fibular origin of the lateral ligament complex and capsule. The repairs of the anterior talofibular complex and capsule and the subsequent surgical excision of the cartilaginous or bony fragment resulted in functionally stable ankles at follow-up examinations. In our opinion, instability of the ankle secondary to an avulsion injury of the anterior talofibular ligament is distinct and different from the finding known as os fibulare (a secondary ossification center of the distal fibula). Our conclusions are based on four findings. First, the area of localized tenderness of the anterior lateral ligament complex accurately represented the osteochondral fracture that was confirmed using radiographic examination. Second, swelling and tenderness recurred over the lateral ligament complex. Third, all the patients had established pseudoarthroses that were identified at surgery and documented histologically. Fourth, all osteochondral fragments were anatomically associated within the lateral talofibular ligament complex and the attachment of the osteochondral fragment to the talofibular ligament complex. CONCLUSIONS If the skeletally immature athlete has chronic ankle instability with an associated osteochondral fracture of the distal fibula, operative treatment is appropriate to guarantee a return to strenuous activity. Our results suggest a procedure that includes excision of the osteochondral fragment and anatomic repair of the ankle capsule and anterior talofibular complex. This method of operative treatment offers the best subjective and objective results. REFERENCES 1. Boruta PM, Bishop JO, Braly WG, et al: Acute lateral ankle ligament injuries A literature review. Foot Ankle 11: , Brooks SC, Potter BT, Rainey JB: Treatment for partial tears of the lateral ligaments of the ankle A prospective trial. Br Med J 282: , Brostrom L: Sprained ankles VI. Surgical treatment of chronic ligament ruptures. Acta Chir Scand 132: , Garrick JG: The frequency of injury, mechanism of injury, and epidemiology of ankle sprains. Am J Sports Med 5: , 1977

651 5 Glick JM, Gordon RB, Nishimoto D The prevention and treatment of ankle injuries Am J Sports Med 136-141, 1976 6 Gould N, Seligson D, Gassman J Early and late repair of lateral ligament of the

5 651 5 Glick JM, Gordon RB, Nishimoto D The prevention and treatment of ankle injuries Am J Sports Med , Gould N, Seligson D, Gassman J Early and late repair of lateral ligament of the ankle Foot Ankle , Griffiths JD, Menelaus MB. Symptomatic ossicles of the lateral malleolus in children J Bone Jomt Surg 69B , Hamilton WG, Thomson FM, Snow SW The modified Brostrom procedure for lateral ankle instability Foot Ankle , Hoed DD A separate centre of ossification for the tip of the internal malleolus Br J Radiol , Kannus P, Renstrom P Treatment for acute tears of the lateral ligaments of the ankle J Bone Joint Surg 73A , Karlsson J Chronic lateral instability of the ankle joint A clinical, radiological and experimental study Medical dissertation, German University, Goteborg, Sweden, Karlsson J, Lansinger O Separate centre of ossification of the lateral malleolus with instability of the ankle joint Arch Orthop Trauma Surg , Love SM, Ganey T, Ogden JA Postnatal epiphyseal development The distal tibia and fibula J Pediatr Orthop 10 : , Mack RP Ankle injuries in athletics Clin Sports Med , Ogden JA, Lee J Accessory ossification patterns and injuries of the malleoli J Pediatr Orthop , Ogden JA, McCarthy SM Radiology of postnatal skeletal development VIII Distal tibia and fibia Skeletal Radiol , Paterson FW, Benjamin A Instability of the ankle due to a separate centre of ossification in the lateral malleolus Injury , Powell HDW Extra centre of ossification for the medial malleolus in children: Incidence and significance J Bone Joint Surg 43B , Vahvanen V, Westerlund M, Nikku R Lateral ligament injury of the ankle in children Follow-up results of primary surgical treatment Acta Orthop Scand , 1984

Clin Podiatr Med Surg 19 (2002) Index

Clin Podiatr Med Surg 19 (2002) 335 344 Index Note: Page numbers of article titles are in bold face type. A Accessory soleus muscle, magnetic resonance imaging of, 300 Achilles tendon injury of, magnetic