Knee Surg Sports Traumatol Arthrosc DOI 10.1007/s00167-015-3660-2

ANKLE

The improvement of postural control in patients with mechanical ankle instability after lateral ankle ligaments reconstruction Hong‑Yun Li1 · Jie‑Jiao Zheng2 · Jian Zhang1 · Ye‑Hua Cai3 · Ying‑Hui Hua1 · Shi‑Yi Chen1 

Received: 21 October 2014 / Accepted: 19 May 2015 © European Society of Sports Traumatology, Knee Surgery, Arthroscopy (ESSKA) 2015

Abstract  Purpose  Lateral ankle sprain is the most common injury. A previous study demonstrated that patients with mechanical ankle instability suffered deficits in postural control, indicating that structural damage of the lateral ankle ligaments may produce a balance deficit. The purpose of this study was to confirm that lateral ligaments reconstruction could improve postural control in patients with mechanical ankle instability. Methods  A total of 15 patients were included in the study. Each patient had a history of an ankle sprain with persistent symptoms of ankle instability and a positive anterior drawer test and had been treated nonoperatively for at least 3 months. All patients were diagnosed with lateral ankle ligaments tear by ultrasonography and magnetic resonance imaging. They underwent arthroscopic debridement and open lateral ankle ligaments reconstruction with a modified Broström procedure. One day before and 6 months after the operation, all of the participants underwent single-limb postural sway tests. The anterior drawer test and the American Orthopedic Foot and Ankle Society scale score were used to evaluate the clinical results in these patients. Results  At 6 months after the operation, with the patients’ eyes closed, there was significantly decreased postural * Ying‑Hui Hua [email protected] 1

Sports Medicine Center of Fudan University, Department of Sports Medicine and Arthroscopy Surgery, Huashan Hospital, Fudan University, No. 12 Urumq Middle Road, Shanghai 20040, China

2

Department of Rehabilitation Medicine, Huadong Hospital Affiliated to Fudan University, Shanghai 200040, China

3

Department of Ultrasonography, Huashan Hospital, Shanghai 20040, China





sway in the anteroposterior direction, the circumferential area, and the total path length on the operated ankles compared with those measurements before the operation. With eyes open, however, no difference was found in postural sway before and after the operation. Conclusions  Postural control was improved by reconstructing the lateral ligaments. Level of evidence IV. Keywords  Ankle instability · Postural sway · Mechanical · Ligament reconstruction

Introduction Acute lateral ankle sprain is the most common sport-related injury, with more than 20 % of these patients having persistent symptoms and chronic instability of the ankle [24]. Chronic ankle instability (CAI) may be subdivided into mechanical and functional ankle instability, each of which may lead to repetitive ankle sprains. Previous study discussed the notion of mechanical instability as a cause of CAI due to pathologic laxity after ankle ligament injury [11]. In contrast, patients with functional ankle instability do not exhibit any such laxity. This type of instability is associated with several functional changes around the ankle, including balance deficits, joint position sense deficits, delayed peroneal muscle reaction times, and strength deficits [11]. Postural sway is a reflection of the dynamics of the postural control system associated with maintaining balance during quiet standing, which is one of the most common parameters for detecting balance inability. A previous study revealed that patients with mechanical ankle instability have greater postural sway than patients with functional

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ankle instability or healthy people, especially in the anteroposterior direction. This finding indicates that it may be structural damage of the lateral ankle ligaments that produces a balance deficit [4]. The role of ankle stabilization surgery in increasing postural control was evaluated in this study. It was hypothesized that postural control could be improved after reconstructing ankle lateral ligaments in patients with mechanical ankle instability. The primary outcome measure was the mean deviation from the centre of pressure (COP) during the single-leg standing test in these patients.

Knee Surg Sports Traumatol Arthrosc

The study included 11 men and four women. Among the 15 patients, seven of them had ankle problems on the left side and eight on the right side. The patients’ median age was 29 years (range 21–42 years), height 175 cm (range 158–182 cm), weight 75 kg (range 51–85 kg), body mass index 24.7 kg/m2 (range 19.9–31.2 kg/m2), and duration of symptoms 36 months (range 12–120 months). Three of the patients reported participating in some level of athletic sport before the operation. Mechanical laxity measures Ultrasonography

Materials and methods From September 2012 to August 2013, a total of 15 patients 18–60 years of age were included in the study. Informed consent was received from each patient. All patients underwent arthroscopic debridement and open reconstruction of the lateral ankle ligaments with a modified Broström procedure performed by the same surgeon. One day before the operation, each participant performed a single-limb postural sway test. Physical examination using the anterior drawer test and the American Orthopedic Foot and Ankle Society scale (AOFAS) score was evaluated as well. The postural sway tests, anterior drawer test, and the AOFAS score were re-evaluated 6 months post-operatively. The inclusion criteria for this study were as follows: (1) history of an ankle sprain with persistent symptoms of ankle instability (e.g. “giving way”) or signs of inflammation (e.g. pain and swelling) for at least 12 months; (2) at least one interrupted day of desired physical activity [8]; (3) the most recent injury must have occurred more than 3 months prior to the study; (4) positive anterior drawer test; and (5) nonoperative treatment for at least 3 months. Also, all of the patients were identified with injuries of the lateral ankle ligaments—including the anterior talofibular ligament (ATFL) and/or the calcaneofibular ligament (CFL) by ultrasonography (US) and magnetic resonance imaging (MRI). The exclusion criteria for the patients were as follows: (1) previous injury or surgery to the lower limb; (2) balance or motion disorder; (3) cavus feet; (4) tendon injury of the lower leg or ankle; (5) required use of foot orthotics; (6) any open wound on the foot [22]; (7) grade IV chondral injury; (8) ankle arthritis; (9) neurologic disease; (10) bilateral ankle disease; (11) vestibular problems; and (12) acute injury to musculoskeletal structures of other joints of the lower extremity during the previous 3 months that affected joint integrity and function [8]. Also, if the lateral ligaments were seen to be completely absorbed on US and MRI examinations, the patients were excluded from the study.

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The ultrasonography (US) examination was described in our previous study [4]. An ALT HDI 5000 US unit (Philips Medical Systems, Bothell, WA, USA) was used. Patients were placed in a supine position with the ankle passively placed in a position of maximum inversion and plantar flexion. The US criteria for ligament injury were ligament tear, ligament laxity, ligament thickening, ligament absorption and nonunion of avulsion fracture of the lateral malleolus [15]. Magnetic resonance imaging MRI was performed with a 1.5-T HD Twin-speed MR scanner (Signa; GE Medical Systems, Milwaukee, WI, USA) using a 20-cm extremity coil, which was described in our previous study [4]. The diagnostic criteria for determining a ligament injury were discontinuity, wavy or curved contour, and increased signal intensity within the ligament. A ligament injury was diagnosed upon fulfilment of any one of these criteria [23]. Instrumentation All patients were assessed for postural sway on a Kistler force plate (Model 9284; Kistler Instruments AG, Winterthur, Switzerland). The average distances from the mean COP in the mediolateral (x) and anteroposterior (y) directions were recorded during quiet standing on the force plate with one leg for 10 s [18]. The circumferential area and path length of the COP were also recorded. Each patient performed three tests on each leg, with and without eyes open, with a 2-min rest period between the tests. Under these two conditions, the patient was asked to stand on just one leg as still as possible, and the arms were held loosely by the sides, and the contralateral knee in flexion at a 45° angle. Shoes were not worn. The standing foot was placed on a longitudinal reference line on the platform extending from the first space between

Knee Surg Sports Traumatol Arthrosc

the big and second toes and the centre of the heel. During the tests with vision (eyes open), the patient was asked to focus on a point on the opposite wall at eye level. During the tests without vision (eyes closed), the patient was asked to close his or her eyes when ready [22]. If the participant touched down with the opposite limb, made contact with the standing limb, or was unable to maintain the standing posture during the 10-s trial, the trial was terminated and repeated [18]. This method used in the single-limb standing test has been judged to be reliable [22, 26]. The advantages of the static balance test are that (1) it is easier to perform and safer than dynamic tests, and (2) the test can be performed outside a laboratory [5]. Surgical procedure Each patient underwent ankle arthroscopic debridement and an open modified Broström anatomical reconstruction. A senior surgeon specializing in ankle arthroscopy and sports medicine performed the surgery [14]. The patient was placed in the supine position with the knee flexed about 45°. Ankle arthroscopic evaluation was performed before reconstructing the ligaments. The lesions in the joint were assessed and managed. The criteria for determining ligament injury were (1) an abnormal course of the ligament at its attachment to the fibula or talus, (2) narrowing of the ligament, and (3) discontinuity of the ligament with or without the defect filled by fibrous tissue [28]. If the remnant of the ligament was deficient or was too thin to be repaired, the patient was excluded from this study. The modified Broström procedure was performed after the arthroscopic evaluation. After the operation, the ankle was immobilized in a slightly everted position by the use of a short leg cast. Weight bearing was permitted 4 weeks later. The cast was removed 2 weeks post-operatively. The research was approved by the Research Ethics Committee of Fudan University (KY2012-136).

Results All of the injured lateral ankle ligaments were diagnosed using MRI and US. US revealed eight cases of tears of the ligaments, three cases of relaxation of the ligaments, two cases of thickening of the ligaments, and two cases of avulsion fracture. MRI revealed ten cases of discontinuity of the ligaments, three cases of wavy or curved contour, and two cases of increased signal intensity within the ligaments. Intra-articular lesions accompanying the injuries were found in 14 ankles (93.3 %). The various pathologic entities are shown in Table 1. Six months after the operation, with eyes closed, the unstable ankles showed significantly decreased postural sway in the anteroposterior direction, circumferential area, and total path length when compared with those measurements obtained preoperatively (Table 2). With eyes open, postural sway showed no difference before and after the operation (Table 3). The stable ankles (controls) showed no difference in postural sway before and after the operation. The median AOFAS score was 63 (range 45–74) before the operation and 80 (range 71–85) at 6 months post-operatively. There was a significant improvement in the AOFAS scores after the operation (p 

The improvement of postural control in patients with mechanical ankle instability after lateral ankle ligaments reconstruction.

Lateral ankle sprain is the most common injury. A previous study demonstrated that patients with mechanical ankle instability suffered deficits in pos...
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