cASe 1 c Scott Hall, MD; Greg Lundeen, MD; Ali Shahin, MD Not just a sprain: University of Nevada-Reno (Drs. Hall and Lundeen); Reno 4 foot and ankle injuries you Orthopedic Clinic, Reno, Nev (Dr. Lundeen); Sierra Family Health, Carson may be missing City, Nev (Dr. Shahin) Sprained ankle is common—and commonly shallmd@specialty health.com overdiagnosed by clinicians who fail to consider these The authors reported no subtle fractures and tendon injuries. Here are 4 to keep potential conflict of interest relevant to this article. in mind. nkle sprain, one of the more common injuries that PrAcTice primary care physicians evaluate, is usually managed recommendatiOnS with conservative treatment. Not uncommonly, how- › A Treat a nondisplaced shaft ever, lateral ankle sprain is diagnosed without consideration fracture of the fifth metatar- of a broader differential diagnosis. sal conservatively, with 6 to Contributing to the problem is the fact that the clinical 8 weeks of immobilization presentation of some fractures and tendon injuries is similar with a protective orthosis. B to that of a routine sprain. In some cases, the mechanism of › Suspect a navicular fracture injury—sprains are usually caused by excessive inversion of in patients who describe a the ankle on a plantar-flexed foot—is similar, as well. What’s gradual onset of vague, dorsal more, radiographs are often omitted or misinterpreted. midfoot pain associated In the pages that follow, we highlight 4 commonly mis- with athletic activity. C diagnosed injuries: fifth metatarsal fractures, navicular frac- › Order magnetic resonance tures, talar dome lesions, and peroneal tendon injuries. These imaging when you suspect injuries should be included in the differential diagnosis of an osteochondritis dissecans, as acute ankle injury—or a subacute foot or ankle injury that radiographs are insensitive for fails to respond as expected. Prompt recognition and appro- identifying these lesions. C priate treatment result in optimal outcomes. When foot and Strength of recommendation (SOr) ankle fractures and tendon injuries are misdiagnosed (or A Good-quality patient-oriented simply missed) and do not receive adequate treatment, long- evidence term morbidity, including frequent reinjury and disability, Inconsistent or limited-quality B 1 patient-oriented evidence may result. C Consensus, usual practice, opinion, disease-oriented evidence, case series Are x-rays needed? Turn to the Ottawa rules Ankle sprains represent a disruption in a ligament supporting a joint, and result in pain, edema, and ecchymosis, and often affect a patient’s ability to bear weight. While uncomplicated sprains generally heal with conservative treatment, other com- mon foot and ankle injuries may require a different approach. 198 The Journal of family PracTice | aPRIL 2012 | Vol 61, no 4 Consider these 4 injuries in the differential: 1. fifth metatarsal fracture 2. navicular fracture 3. talar dome injury 4. peroneal tendon injury The Ottawa foot and ankle rules are and fifth metatarsal (fiGure 1) an evidence-based guide to the use of ini- (3) a shaft fracture, distal to the fifth meta- tial radiographs after acute ankle injury tarsal joint in the proximal diaphysis.6-8 (TABLe 1).2-4 Pain—near the malleoli (for the While avulsion fractures are generally ankle) or in the midfoot—is the key criterion, the result of an inversion ankle injury, Jones but x-rays are recommended only if at least fractures are usually caused by a large adduc- one other specified criterion is also met. With tive force applied to the forefoot on a plantar- a sensitivity of nearly 100%, the rules have flexed ankle.6 Shaft fractures, also known as been shown to reliably exclude, and diag- diaphyseal stress fractures, are overuse in- nose, ankle and midfoot fractures in children juries from chronic overload, usually after a >5 years and adults.2,5 sudden increase in running or walking.9 Patients with fifth metatarsal fractures typically have tenderness with palpation fifth metatarsal fractures over the area of injury, with edema and are easily missed ecchymosis when the injury is acute. Evi- The mechanism of injury for a fifth metatar- dence-based guidelines recommend x-rays sal fracture is often similar to that of a lateral of the foot, including anteroposterior (AP), ankle sprain. In addition, isolated ankle ra- lateral, and oblique views.2-4 One study sup- diographs may not adequately evaluate the ports the use of an additional x-ray—an fifth metatarsal, which increases the risk of AP view of the ankle, including the base of misdiagnosis.6 the fifth metatarsal—if clinical suspicion is high and initial radiographs are negative or 3 types of fifth metatarsal fractures inconclusive.10 Fifth metatarsal fractures involve one of the Shaft fractures may not be seen on x-rays following: in the first 3 weeks, but a periosteal reaction or i mage © ko s (1) an avulsion fracture, caused by the pull linear lucency near the symptomatic area may of the plantar aponeurosis and the per- be noticeable on radiographs taken at a later oneus brevis tendon at the tuberosity of date.11 If this overuse injury seems likely but T udios the bone does not show up on the initial x-rays, how- (2) a Jones fracture, at the base of the fourth ever, magnetic resonance imaging (MRI) or a JfPonline.com Vol 61, no 4 | aPRIL 2012 | The Journal of family PracTice 199 table 1 Ottawa ankle and foot rules2-4 ankle X-rays are required only if the patient has pain near the malleolus and one or more of the following: • Bone tenderness along the distal 6 cm of the posterior edge of the tibia or tip of the medial malleolus • Bone tenderness along the distal 6 cm of the posterior edge of the fibula or tip of the lateral malleolus • Inability to bear weight for 4 steps, both immediately after the injury and in the emergency department foot X-rays are required only if the patient has pain in the midfoot and one or more of the following: • Bone tenderness at the base of the fifth metatarsal • Bone tenderness at the navicular bone • Inability to bear weight for 4 steps, both immediately after the injury and in the emergency department While casting of Jones fractures was found to technetium bone scan can reliably identify a there is fracture displacement, absence of have a 44% stress fracture.9 bony union, or high clinical concern.6,17 failure rate, z is your patient an athlete? Surgical surgical screw How to treat, when to refer fixation is favored for injured athletes with fixation was Treatment of fifth metatarsal fractures Jones fractures because failure rates are lower successful nearly range from conservative to surgical, de- and both clinical union and return to play are 100% of the pending on the type (and extent) of injury shorter.18,19 In a case series involving 23 ath- time. (TABLe 2).1,5,6,12-14 letic patients with Jones fractures, the success z nondisplaced avulsion fractures can rate for immediate surgical screw fixation ap- be treated conservatively, with relative im- proached 100% within 6 to 8 weeks.18 mobilization. In one prospective study, the z nondisplaced shaft fractures may be use of a stiff-soled shoe, with weight-bearing treated conservatively, with 6 to 8 weeks of as tolerated, was associated with excellent immobilization with a protective orthosis. An long-term outcomes.11 Orthopedic referral orthopedic referral is recommended for pa- for probable reduction and fixation is indi- tients whose fractures have >3 mm displace- cated for avulsion fractures that are com- ment or >10 degree angulation.15 minuted or >2 mm displaced, or have >30% involvement of the cubometatarsal joint.15,16 z Jones fractures are known for pro- navicular fractures longed healing and nonunion, as well as a are overuse injuries high rate of complications. If the fracture is The navicular is predisposed to stress injury nondisplaced, start with conservative treat- because the central third of the bone is rela- ment, consisting of nonweight-bearing im- tively avascular. In addition, the navicular is mobilization for 6 to 8 weeks, with additional the area of greatest stress and impingement immobilization dependent on radiographs. between the talus and cuneiform bones dur- One randomized controlled trial of patients ing repetitive foot strikes.12,20 Navicular frac- with Jones fractures showed a relatively high tures occur predominantly in track and field failure rate (44%) with casting; patients for athletes.12 whom casting was successful still had a me- Patients presenting with a navicular dian time to bony union of 15 weeks.17 Spe- stress fracture often report a gradual onset cialty consultation may be needed when of vague dorsal midfoot pain associated with 200 The Journal of family PracTice | aPRIL 2012 | Vol 61, no 4 FOOT AND ANKLE INJURIES FIGURE 1 Jones fractures heal slowly a B c IMAGES COUR T ESY OF navicular : SCO fractures—stress TT HALL injuries , primarily MD affecting track This 50-year-old patient presented with pain and swelling in the ankle and lateral foot shortly after an inversion ankle injury. a radiograph (A) taken at that time reveals a Jones fracture. The second radiograph (B) was taken 6 weeks later, and field after continued immobilization with no weight-bearing. Three months after the injury (c), the patient was clinically athletes—are asymptomatic. associated with a gradual onset their workout.17 Examination typically reveals letes usually able to return to play within of midfoot pain. tenderness on palpation over the dorsal as- 6 months.22,24,25 If tenderness remains after pect of the navicular; passive eversion and 6 to 8 weeks of immobilization, treatment active inversion may be painful, but edema choices are continued immobilization with and ecchymosis are usually absent.21 no weight-bearing or orthopedic referral.26 When pain is elicited by palpation of the Referral is indicated for navicular frac- navicular, radiographs are recommended.2,6 tures that are comminuted or displaced, or X-rays have a relatively low sensitivity (33%), involve more than one bone cortex.26 Surgi- however, for detecting acute navicular stress cal screw fixation may be recommended for fractures.