CHAPTER 40
Articulation Injuries of the Ankle and Hip
Robert Keith, MPA, PA-C, CCPA • Karen Anderson Keith, PhD, RN
Articulation injuries, also known as joint injuries, occur where two bones join. The injury may result from acute or chronic trauma or from the destruction of articular cartilage. This chapter discusses the examination of an injured joint in general, and specifically the evaluation of the ankle and hip joints. Conditions that result in or may be associated with articulation injuries of the upper extremities, lower back, and knee, or those that result from underlying degenerative or destructive processes, are discussed in separate chapters in this unit.
Primary care providers frequently encounter patients with articulation injuries, making basic competency in their evaluation and management a necessity. Through the relationships they have established with their patients, primary care providers are often in the best position to assess the immediate impact of acute articular injuries on the patient’s activities of daily living and social life. Additionally, awareness of predisposing or comorbid medical conditions allows nuanced management of the problem. This chapter provides an overview of how to examine an injured joint, followed by specific information on evaluating the ankle and hip. Definitions of articulation injuries are presented in Table 40.1.
GENERAL APPROACH TO THE JOINT EXAMINATION
Some examination criteria are unique to each joint, but the following items are important in the evaluation of injury to any joint. The physical examination of the acutely injured joint should be undertaken as soon as feasible. As time progresses, edema, muscle spasm, pain, and joint effusion make the accurate elicitation of physical findings more difficult. Reexamination of the injured joint several days after acute inflammation has subsided frequently yields results more accurate than those obtained during the initial evaluation (Ivins, 2006; Kerkhoffs et al., 2012). As in most cases, the physical examination begins with inspection of the suspected joint. Inspection may reveal deformity, erythema, ecchymosis, and edema. Palpate for point tenderness, crepitus, deformity, increased warmth, and pulses. Check for neurological injury by testing for proprioception and light sensation in the involved joint. Ask the patient to move the joint through the full range of motion (active range of motion). To evaluate the status of a joint on physical examination, it is necessary to stress the involved joint and evaluate it for stability. Whether the patient is successful or unsuccessful in moving the joint, attempt passive range of motion. Compare the range of motion bilaterally. Motion against resistance can be used to assess neuromuscular function and assess for possible ligament or tendon disruption. Document the vascular status of the area by recording pulses and capillary refill time at a site distal to the injury. As in all joint injuries, it is important that joints directly proximal and distal to the injury also be examined for collateral damage.
In almost all cases of nontraumatic presentation, the differential diagnosis includes osteoarthritis or rheumatoid arthritis. Age, onset of symptoms, and typical patterns of pain are helpful when assessing the etiology of any joint pain. When monoarticular pain is present in the absence of a clear-cut instance of trauma or gout, an infected joint is a clear possibility. If an infected joint becomes prominent in the differential diagnosis, joint aspiration must be done to rule out an infectious or crystal-induced etiology. Failure to identify an infected joint can rapidly lead to catastrophic consequences.
ANKLE INJURIES
Anatomy, Physiology, and Pathology
The ankle is a complex joint that carries the full weight of the body. Simply walking loads the joint with forces 1.5 times the resting body weight (Sandberg-Cook, 2013). The ankle joint is formed by the articulation of the distal ends of the tibia and fibula with the calcaneus in the foot. The integrity of the ankle is maintained by a “ring” alternating between bone and three sets of ligaments: the lateral collateral ligament complex, the syndesmotic ligament complex, and the medial collateral ligament complex (Eiff, Hatch, & Calmback, 2003; Okanobo et al., 2012). The ankle is composed of four major ligaments that are of concern during the assessment of an acute injury. An excellent depiction of the ankle is available at www.aafp.org/afp/2006/1115/p1714.html (Ivins, 2006). Because the overwhelming majority of ankle sprains are the result of inversion of the foot, the three ligaments on the lateral aspect of the foot are most in need of evaluation (Hubbard & Wikstrom, 2010; Ivins, 2006). The anterior talofibular ligament (ATFL) extends from the anterior aspect of the distal fibula to its insertion on the lateral talus (Kadakia, 2010). This ligament is the one most often injured when the ankle is suddenly inverted, typically while in plantar flexion, with 66% of ankle sprains confined to the ATFL (Hubbard & Wikstrom, 2010). Moving laterally and posteriorly is the calcaneal fibular ligament (CFL) that links the posterior-inferior aspect of the fibula with the middle of the calcaneus. The posterior talofibular ligament (PTFL) is a short, strong, intracapsular ligament that runs posteriorly from the posterior lateral malleolus and attaches to the posterolateral surface of the talus. During inversion injuries, the ligaments are usually injured sequentially (ATFLn, then CFL, and finally PTFL) as increasing force is applied to invert the ankle (Okanobo et al., 2012).
TERM | DEFINITION |
Sprain | Complete or partial tear in a ligament or joint capsule
|
Strain | A torn muscle–tendon unit |
Tendinitis | Inflammation of tendon |
Tenosynovitis | Inflammation of the tendon sheath |
Bursitis | Inflammation of a bursa |
Fracture | Any break in the continuity of a bone |
Dislocation | Complete loss of continuity between two opposing articular surfaces |
Delayed union | A fracture that takes >6 months to heal |
Nonunion | Failure of a fracture to heal after 1 year |
Subluxation | Partial dislocation |
Epicondylosis | Arthritic changes in a joint |
On the medial side of the ankle, the deltoid ligament is a strong, five-component band that joins the distal medial malleolus of the tibia to the talus. This ligament is so strong that it often yields an avulsion fracture of the medial malleolus rather than rupturing when force is applied to it in an eversion type of injury. The high ankle sprain, which occurs most commonly in collision sports, results from injury to the syndesmosis between the distal fibula and tibia. While not common, it can be overlooked if not considered in the differential diagnosis; if not correctly identified, the injury may lead to a long period of rehabilitation (Saluta & Nunley, 2010).
Epidemiology
Ankle injuries are a major health concern, accounting for more than 20% of all sports injuries. In the United States more than 25,000 ankle injuries occur each day, resulting in an estimated 2 million office visits and 11,000 hospital visits each year. This represents an incidence of about 1 injury per 10,000 to 13,000 people each day (Ivins, 2006; Seah & Mani-Babu, 2010; Wähnert et al., 2013; Wikstrom, Wikstrom, & Hubbard-Turner, 2012; Young, Niedfeldt, Morris, & Eerkes, 2005). More than half of those injured will fail to seek medical advice (Hubbard & Wikstrom, 2010). Though often considered inconsequential, ankle injuries result in a significant morbidity: 30% to 75% of those injured live with chronic instability.
Diagnostic Criteria
Fractures are ruled out with x-rays of the ankle, foot, and lower leg, as indicated by the history and physical examination. In selected instances, additional imaging techniques (e.g., CT, ultrasound, MRI) may be indicated, most often when x-rays are negative but the clinical suspicion for injury remains high.
History and Physical Examination
The history should begin with questions directed at determining the mechanism of injury (O’Rorke, 2005; Seller, 2007). The mechanism of injury provides important insights about the magnitude of the forces involved and the likelihood of significant injury. Other key points include:
Did the patient hear or feel any snap or pop?
Was weight bearing or continued activity possible just after the injury?
Is there numbness or tingling in the involved extremity?
Was the onset sudden? If chronic, was it associated with a specific overuse activity?
How does the injury affect the patient’s activities of daily living?
Is the injury to the dominant limb?
General questions about overall physical activity and fitness help to situate the injury in the context of the patient’s life and anticipate the response to rehabilitation efforts. Ask about any chronic or recurrent joint pain, fever, or rash; review any medications the patient takes; and check for allergies. Explore previous surgery or rehabilitation for orthopedic problems.
Patients present most commonly with a history of having had their foot inverted as a result of weight bearing on an uneven surface. The patient often describes a popping sensation when significant injury occurs (Bailitz, Bokhari, Scaletta, & Schaider, 2011). This does not necessarily mean that the ligament has ruptured or a fracture is present, but it does increase the likelihood of significant injury. If disruption involves two or more components of the “ring,” the injury is considered unstable. Injuries that are isolated to the ATFL are three times more common than injuries that include the CFL or the PTFL (Hubbard & Wikstrom, 2010; Li & Meals, 1992). As a result, most ankle injuries are stable and can be treated conservatively with functional interventions (various supportive devices) and early mobilization. Although inversion is the mechanism of injury about 85% of the time, supination external rotation (SER) injuries are the most common cause of ankle fractures, accounting for between 40% and 70% of all ankle fractures (Okanobo et al., 2012; Zohman & Meals, 1992).
Inspect the foot and ankle for edema and ecchymosis. The rapidity and extent of these conditions are helpful clues in judging the extent of injury. The so-called Figure 8 Technique can be used as a reliably reproducible measure of edema (Wikstrom, et al., 2012). This is performed by draping a flexible tape measure around the ankle, down and across the proximal area of the midfoot, and then back around the ankle in a manner implied by the name of the procedure. On follow-up, repeated Figure 8 Techniques can be used to monitor progress and the resolution of edema.
Careful palpation of the lateral margin of the foot over the site of the ATFL insertion will elicit pain if significant injury is present. The anterior drawer sign is performed by stabilizing the distal tibia and grasping the calcaneus while pulling it anteriorly. This test is positive for ATFL injury if significant laxity is found upon examination when compared to the uninjured ankle (Polzer et al., 2012; Wikstrom et al., 2012). The ability to bear weight for at least four steps has been highly correlated with grade I or II sprains. Stress testing by inverting and everting the foot has also been shown to be predictive of abnormalities on x-ray. If the foot can be inverted and has a talar tilt of <15°, then most likely only the ATFL is involved. If the tilt is 15° to 30°, then the ATFL and the CFL are affected. With more than 30° of tilt, all three lateral ligaments of the ankle are torn, and the risk of associated fracture is high (Seligson & Voos, 1997). If all three ligaments are compromised, an early orthopedic referral is indicated.
The cross-leg test is positive in high ankle sprains and is performed by having the patient sit and place the lower portion of the injured leg across the contralateral knee while the examiner applies a gentle downward force on the foot, compressing the tibia against the fibula. Eliciting pain is a positive response. Alternatively, the squeeze test, performed by squeezing the tibia and fibula in the midcalf region, will elicit pain distally in the ankle if there is an injury to the syndesmosis. Pictures of these techniques are available in Polzer et al. (2012), Figures 4 and 5, which can be found at www.pagepress.org/journals/index.php/or/article/view/3751.
Although ankle injuries are quite common, the diagnosis must be made based on a complete and careful examination; premature closing of the diagnostic loop must be avoided (Ely, Graber, & Croskerry, 2011; Ely, Kaldjian, & D’Allesandro, 2012; Graber, 2009). Injuries that can easily be missed include calcaneal fractures, talar dome injuries, high ankle sprains, and Maisonneuve fractures (Judd & Kim, 2002; Saluta & Nunley, 2010; Wähnert et al., 2013). Specific discussion of these injuries is beyond the scope of this review; failure of conservative measures to provide consistent improvement should alert the clinician to consider additional imaging and/or referral to an orthopedic specialist (Espinosa & Valderrabano, 2010).
Diagnostic Studies
In the past, evaluation of a sprained ankle almost always included x-rays; however, only 15% of ankle x-rays were found to be positive for a fracture (Stiell, Greenberg, & McKnight, 1992; Stiell, McKnight, & Greenberg, 1994). Ongoing efforts to reduce the number of unnecessary x-rays have resulted in validated clinical decision rules to guide x-ray usage (Bachmann, Kolb, Koller, Steurer, & Ter Riet, 2003; McAlinden & Teh, 2007). The Ottawa Clinical Decision Guidelines, possibly the most widely known, include the following:
Inability to bear weight immediately after the injury
Inability to take at least four unsupported steps during the office evaluation
Point tenderness on palpation of the posterior aspect of either malleolus or in the midfoot zone where the proximal metatarsals articulate with the navicular bone (Bachmann et al., 2003; Stiell et al., 1992, 1994).
By using the Ottawa Ankle Rules (OAR), studies indicate that virtually all patients with ankle fractures will be correctly identified (sensitivity of approximately 100%), but specificity for ankle fracture was low (49%) (Bachmann et al., 2003; Stiell et al., 1992, 1994). In the absence of the findings just listed, however, there is virtually no chance that a fracture is present (a negative predictive value of 100%). Implementation of these rules in follow-up studies with more than 2,300 patients led to a 28% decrease in ankle x-rays, decreased time for evaluation, and no untoward outcomes (Stiell et al., 1992, 1994). More recent studies have shown that despite widespread awareness of the OAR, implementation has not had the impact on decreasing x-ray requisitions originally anticipated (Bachmann et al., 2003).
When indicated, x-rays should include anteroposterior, lateral, and mortise views (Frey, 2004, 2005). The mortise view is performed with the foot internally rotated 15°; this allows the ankle joint to be visualized without overlapping of the distal tibia and fibula on the calcaneus (Raby, Berman, & DeLacey, 2005; Young, Young, & Chan, 2007). When a mortise view is reviewed, one should check for even spacing throughout the joint. Magnetic resonance imaging plays virtually no role in the evaluation of acute ankle injuries in the primary care setting. If concern remains after evaluation, prompt orthopedic referral while initiating conservative management is indicated.
Treatment Options, Expected Outcomes, and Comprehensive Management
Injuries to major joints are frequent, and common underlying principles of evaluation and management allow the provider to safely and effectively manage the early phases of the overwhelming majority of these cases. The acronym PRICE (protection, rest, ice, compression, elevation) is useful in guiding the initial care of articular injuries. Protection is most often accomplished by the application of some type of external support, such as a splint. Preventing further injury is a paramount concern when evaluating injuries at the scene of an accident. A patient who arrives at the office with an unsplinted joint injury should have a splint applied immediately after evaluation.
Rest is a natural continuation of protection. Rest is not always complete inactivity, but usually involves significant reduction in the intensity or frequency of use of the involved joint.
Ice is the most common form of cryotherapy. Cold applied during the first 24 to 48 hours after injury has several beneficial effects. Pain reduction and decreased edema set the stage for rapid mobilization of the joint. (Rapid mobilization has significant advantages over prolonged immobilization.) Ideally, cold should be applied for 15 to 30 minutes every 3 hours (Kerkhoffs et al., 2012).
Compression and elevation decrease edema and pain during the initial phase (24 to 72 hours) of management. When using compression in the form of an elastic bandage, care should be exercised to avoid circulatory compromise. Only moderate tension should be applied to the bandage; if discomfort ensues, the bandage should be released. Once the patient begins to ambulate, an elastic bandage is considered inadequate support (Wikstrom, Wikstrom, & Hubbard, 2010).
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