Arthroscopic treatment of anterolateral impingement of the ankle* RICHARD D. FERKEL,† MD, RONALD P. KARZEL, MD, WILSON DEL PIZZO, MD, MARC J. FRIEDMAN, MD, AND SCOTT P. FISCHER, MD From the Southern California
Van
Nuys,
California
care.’ While most ankle sprains apparently heal without
ABSTRACT
sequelae after conservative therapy, a recent study of basketball players who had ankle sprains found that 50% had residual symptoms, with 15% symptomatic enough to compromise their playing performance.&dquo; Studies of ankle injuries emphasize that the most common mechanism of ankle injury is plantar flexion/inversion, resulting in injury to the lateral ligamentous complex of the ankle in over 90% of the cases.1 Not surprisingly, therefore, chronic lateral ankle pain after ankle sprain is much more common than chronic medial pain. To appreciate abnormalities in the lateral gutter of the ankle, it is necessary to understand the normal anatomy of
We studied 31 patients (17 females, 14 males; average age, 34) with more than 2 years of followup who had chronic anterolateral ankle pain following inversion injury. All had failed to respond to at least 2 months of conservative treatment and had negative stress radiographs to rule out instability. On physical examination, tenderness was localized to the anterolateral corner of the talar dome. Magnetic resonance imaging was the most useful diagnostic screening test, showing synovial thickening consistent with impingement in the anterolateral gutter. At an average of 24 months after injury, all patients underwent ankle arthroscopy, which showed proliferative synovitis and fibrotic scar tissue in the lateral gutter, often with associated chondromalacia of the talus. Operative arthroscopic treatment consisted of partial synovectomy with debridement of scar tissue from the lateral gutter. Postoperatively, patients walked with crutches allowing weightbearing as tolerated. Average return to sports was 6 weeks. Histopathologic analysis performed on the resected tissue showed synovial changes consistent with chronic inflammation. Results of treatment after at least 2 year followup were 15 excellent, 11 good, 4 fair, and 1 poor. Since there are several distinct causes of chronic ankle pain, we prefer to call this problem "anterolateral impingement of the ankle" and believe the term "chronic sprain pain" should be discarded.
this
The borders of the lateral gutter include the talus
sectional view demonstrates that the lateral gutter space extends from anterior to posterior between the fibula and talus (Fig. 3). The etiology of chronic lateral pain after an inversion injury of the ankle is often elusive, particularly in patients whose ankles are stable on examination and in stress radiographs. Wolin and colleagues&dquo; in 1950 described nine patients with persistent pain and swelling over the anterolateral aspect of the ankle several weeks to months after an inversion sprain. Arthrotomy of the ankle in these patients revealed a mass of hyalinized connective tissue extending into the joint from the anteroinferior portion of the talofibular ligament. They labelled this tissue a &dquo;meniscoid&dquo; lesion because it looked like a torn meniscus in the knee. They felt that disability resulted from entrapment of this lesion between the fibula and talus. Excision of the scar tissue relieved the symptoms in all cases. More recently, W aller14 identified a group of patients with &dquo;anterolateral corner compression syndrome,&dquo; which he believed resulted in pain
Ankle
sprains are among the most frequently observed inin athletics, with one recent large survey showing a 16% incidence of these injuries in athletes seeking medical *Presented at the 15th annual meeting of the AOSSM, Traverse
area.
medially, the fibula laterally, and the tibia with the tibiofibular ligament superiorly. Anteriorly, the lateral gutter is bordered by the anterior talofibular, calcaneofibular, and anterior inferior tibiofibular ligaments (Fig. 1). Posteriorly, the border includes the posterior talofibular, calcaneofibular, and posterior inferior tibiofibular ligaments (Fig. 2). A cross-
juries
Michigan, June 22,1989 t Address correspondence and reprmt requests to Richard Southern California Orthopedic Institute, 6815 Noble Avenue,
Orthopedic Institute,
City,
D Ferkel, MD, Van Nuys, CA
91405 440
441
along the anteroinferior border of the fibula and the anterolateral talus. His patients had valgus heels with pronated feet, and he believed this was a synovial compression syndrome dome.
or
chondromalacia of the lateral wall of the talar
Subsequently, there have been few references to this lesion began to share their findings from the arthroscopic management of chronic ankle sprains. In this paper, we report on the diagnosis and arthroscopic treatment of a group of patients with persistent lateral ankle pain after an inversion injury. We have labelled this problem &dquo;anterolateral impingement of the ankle&dquo; to distinguish it from other causes of chronic ankle pain. until surgeons
MATERIALS AND METHODS
Approximately 2000 patients at the Southern California Orthopedic Institute were treated for ankle sprains between 1983 and 1989. A diagnosis of anterolateral impingement was made in 43 patients (2%), all of whom underwent ankle arthroscopy. This was 25% of the 170 ankle arthroscopies performed by surgeons in our group from June 1984 to April 1989. We excluded 12 patients who had an associated fracture or who had less than 24 months of postoperative followup, resulting in a group of 31 patients whom we then studied retrospectively. Patient records and operative videotapes were reviewed for all patients. Ankle range of motion, stability, swelling, and tenderness were evaluated at follow-up examination. Each patient was also interviewed and asked questions about the present status of the ankle. An objective ankle rating scale (reported by Bray and coworkers2) was used to assign a numerical rating to each patient (Table 1). Patients were also asked to rate their ankles subjectively. The patient group consisted of 17 females and 14 males.
Figure 2.
Posterior borders of the lateral
gutter.
Figure 3. Cross-section through area of lateral gutter. The average age was 34, with a range from 16 to 74. There 19 injuries to the right ankle and 12 to the left ankle. All patients had sustained a previous &dquo;sprain&dquo; to their ankles, with 17 patients giving a history of plantar flexion/ inversion and 14 patients unsure as to the position of the ankle at the time of injury. Six of the patients had multiple previous sprains prior to the most recent major event. Fifteen patients injured their ankles at work, 11 in sports activities, and 5 had other sources of injury. Five patients had previous surgery on their ankles: removal of bone spur or bone fragment (two), Evans procedure (one), repair of a torn anterior talofibular ligament (one), and tarsal tunnel release (one). The most common presenting history was that of a prior ankle sprain followed by chronic persistent ankle pain with ambulation, weakness, and frequently a sensation of giving way. Physical examination revealed localized moderate to were
Figure 1. Anterior borders of the lateral gutter. (From Ferkel and Fischer,5 with permission.)
442
TABLE 1
Scoring for evaluation of anklesa
°
Total subtracted from 100 points: 90-100, excellent; 75-89, good; 50-74, fair; less than 50, poor.
tenderness of the anterolateral gutter of the ankle. Patients typically had normal or only slightly limited ankle motion. Any patients with inversion or anterior laxity of the ankle were not considered to have anterolateral impingement and were excluded from the study. Care was taken to distinguish pain in the lateral gutter of the ankle joint from pain in the area of the sinus tarsi. If the patient appeared to be tender in both areas, the sinus tarsi was injected with a local anesthetic. If injection of the sinus tarsi relieved the symptoms, the diagnosis was not considered to be anterolateral impingement. Plain radiographs were uniformly negative for previous fracture, widening of the ankle mortise, or significant degenerative changes. All of the patients had stress radiographs of the ankle, which were negative for instability. Three patients had magnetic resonance imaging (MRI), which showed increased soft tissue in the lateral gutter (Fig. 4). Two patients had weakly positive bone scans that showed increased uptake in the region of the distal tibia and fibula. With the exception of the MRI scans, the imaging studies were most helpful in excluding other causes of persistent pain such as osteochondral fracture, arthritis, or instability. All of the patients underwent prolonged conservative therapy with varying combinations of physical therapy (100%), nonsteroidal antiinflammatory drugs (100%), immobilization (50%), and steroid injections (62%) before undergoing definitive surgical management. The indications for arthroscopic surgery were a positive history for ankle sprain with subsequent chronic pain and tenderness in the lateral gutter severe
MRI scan showing scar tissue (low-intensity signal) in the lateral gutter of the ankle. Legend: tal, talus; fb, fibula;
Figure 4.
ataf, anterior talofibular ligament. was refractory to conventional treatment modalities in patients with otherwise negative workups. Arthroscopic surgery was performed on all patients in this study at an average of 24 months (range, 3 to 120) after injury. Techniques of the arthroscopic procedure have been detailed previously’ and will not be repeated here. Although we frequently use an ankle distractor during arthroscopy,
that
we
do not recommend
use
of the distractor for all
cases
of
suspected impingement. In some cases, use of the distractor makes visualization of the lateral gutter more difficult, since it tends to put the lateral gutter structures on stretch and compress the space. Generally in impingement cases, the procedure is begun without the distractor, which can be added subsequently if it appears that this will be of benefit. Examination of the entire ankle joint is performed arthroscopically in a systematic fashion. Patients with impingement syndrome have abnormalities that are confined primarily to the lateral side, usually consisting of synovitis and scar tissue and possibly with associated chondromalacia of the talar dome (Fig. 5). Debridement of the hypertrophic soft tissue is performed, as is chondroplasty of the talus, if necessary. In some patients, a meniscoid band is identified and excised (Fig. 6). Care must be taken not to excise the anterior talofibular ligament. Occasionally patients will also have associated synovitis in the distal tibiofibular joint and surrounding anterior tibiofibular ligament; sometimes this is best seen with the distractor. Postoperatively, the patient is placed in a compression
443
appeared inflamed
or hemorrhagic, and had a firmer and elastic consistency than is normally seen with other forms of synovitis (Fig. 7). Twenty patients (64%) had adhesive bands of scar tissue in the lateral gutter in addition to the synovial hypertrophy (Fig. 8). Sixteen patients (51% ) had chondromalacia of the anterolateral talar dome, usually Grades I or II, and occasionally of the distal tibia. Four
more
Figure 5. Arthroscopic visualization of hypertrophic soft tisin lateral gutter. (Reprinted with permission from Dyonics,
sue
Inc.4)
Figure 7. Hemorrhagic synovitis in lateral gutter of right ankle.
Figure 6. Debridement of soft tissue is performed arthroscopically. (Reprinted with permission from Dyonics, Inc.4) dressing and allowed weightbearing as tolerated with crutches. Crutches are discontinued after the lst week and rehabilitation is begun. Return to sports is allowed when the patient is asymptomatic, usually after 6 weeks. ’
RESULTS
Findings at surgery patients were noted to have hypertrophied, inflamed synovium at the time of operation. The synovium usually All
Figure 8. Resection of fibrotic scar band (double arrows) in lateral gutter using band cutter. Talus is marked by single arrow.
444
of the ankle were recorded. All patients were contracted for subjective followup at an average of 33.5 months
patients ( 13 % ) had well-developed bands of scar tissue which were similar to the meniscoid lesions first described by
bility
Wolin et aL 15 These bands extended from the anterior border of the lateral gutter to the posterior border, running freely through the lateral talofibular articulation. Three patients had anterior tibial osteophytes.
postoperatively (range, 24 to 66 months). Using the modified Weber ankle scoring scale from Bray and coworkers,2patients were rated as: 15, excellent; 11, good; 4, fair; and 1, poor. Twenty-nine of 31 patients returned to the same level of physical activity as prior to injury. Four patients did not return to their previous level of sports activities; one of these patients, however, attributed this to a subsequent back injury. The one poor result in a patient occurred early in the series. The patient had pain in the lateral ankle and was treated arthroscopically for anterolateral impingement. Her symptoms initially resolved but recurred 6 months postoperatively. At that time she was noted to have tenderness in the sinus tarsi, and her symptoms temporarily improved after an injection of lidocaine in the sinus tarsi region. She subsequently underwent an open operation with excision of the sinus tarsi, and her symptoms completely resolved. At 3 years after surgery she was asymptomatic. Four patients had fair results. All of these patients had work-related injuries. Three of the four had Grade II chon-
Pathologic findings Histologic analyses were performed on all patients with impingement syndrome. Moderate synovial hyperplasia with subsynovial capillary proliferation was seen in all cases. Also noted in many of the patients were hyaline cartilage degenerative change and fibrosis. These findings were consistent with a chronic inflammatory process (Fig. 9). Clinical evaluation All patients were examined in followup at least 3 months postoperatively, and tenderness, range of motion, and sta-
dromalacia of the talus at the time of surgery. All of these
patients complained of mild constant pain in the ankle and were unable to compete fully in sports activities but had minimal difficulties with the activities of daily living. Two of the patients in this group complained of a sensation of instability in their ankles. Both of these patients had initially done well after surgery but had deterioration of their results at 56 and 45 months, with a sense of increasing instability. In one of these cases, the patient had sustained a repeat injury to the ankle at the time of deterioration. The remaining 26 patients had excellent or good results. They were fully functional at work and in sports. Most had no pain or only minimal pain, which did not require analgesics, after activity. None had a significant loss of plantar flexion or dorsiflexion following arthroscopy. Two returned successfully to collegiate-level athletic activity. Reoperation was required in only one patient; we believe this patient was initially misdiagnosed as having anterolateral impingement and ultimately required excision of the sinus tarsi. No other complications were noted in this group of patients. DISCUSSION
Figure 9. Photomicrographs of resected soft tissue in impingement syndrome. A, synovial hyperplasia with subsynovial capillary proliferation (x100; H&E). B, hyaline cartilage demonstrating degenerative changes (x100; H&E).
This study describes anterolateral impingement syndrome, which can be a cause of chronic lateral ankle pain and disability following a plantar flexion/inversion injury to the ankle. In patients with chronic ankle pain after ankle sprain that is unresponsive to conservative therapy, several causes for the pain must be considered. In addition to chronic instability, pain may be due to osteochondral lesions of the talus, calcific ossicles beneath the malleoli, peroneal subluxation/dislocation or tear, tarsal coalition, subtalar joint dysfunction, or degenerative joint disease. Sinus tarsi syndrome must be differentiated from an impingement problem.l3 We feel that anterolateral impinge-
445
ment may occur occasionally with sinus tarsi syndrome. The exact relationship of these two entities is not clear, but
dysfunction may be the underlying problem. Occasionally, a patient will have pain in both the lateral gutter and subtalar areas and the origin of the pain cannot be determined, even with selective xylocaine injections. Presently, we are simultaneously performing arthroscopy on the ankle and subtalar regions to localize the diagnosis and treatment in this patient group. As more cases are done, a better understanding of this problem will evolve. Radiographic studies have not proven to be useful in diagnosing anterolateral impingement of the ankle, but they subtalar
may be very useful in
ankle
diagnosing other causes of chronic Stress pain. radiographs should be done if persistent
instability
is
suspected. Likewise,
a
recent
study by Meyer
and coworkers1° has demonstrated the value of high-resolution computerized tomography in the diagnosis of chronically painful ankle sprain. They found avulsed intraarticular or juxtaarticular fragments of traumatic origin that were not readily apparent on standard radiographs of 13 patients. A careful clinical examination and selected diagnostic studies should enable the examiner to exclude other causes of chronic ankle pain. Unfortunately, anterolateral impingement cannot be readily diagnosed with conventional imaging tests.
MRI may assist in the diagnosis in some cases, but has also been associated with false-negative results in our patients. Presently, we are developing different coils and planes of imaging to demonstrate the impingement abnormalities more clearly. In addition, a technique of cine MRI is being studied to better understand the ankle in motion. We believe the anterolateral impingement process begins when an inversion sprain tears the anterior talofibular and anterior inferior tibiofibular ligament, occasionally with an accompanying tear of the calcaneofibular ligament. Although the ligament injury is not severe enough to cause chronic instability, repetitive motion may lead to inflammation in the area(s) of the healing ligament(s) with resultant synovitis and formation of scar tissue. As this mass of tissue and synovium increases in size, impingement of the tissue mass between the talus, tibia, and fibula may cause increased irritation and pain, and further increase in inflammatory tissue. The end result is chronic lateral ankle pain’
(Fig. 10). The soft tissue present appears to be primarily synovial origin. Guhl’ has suggested that relatively mild sprains with minimal capsular tearing may result in an intraarticular hematoma that is only slowly reabsorbed. The blood may then be absorbed by the synovium in the lateral gutter and lead to a reactive synovitis. Four of the patients in our study also had meniscoid bands noted at surgery. These have been described by several authors 7,9,11,15 and probably represent a more advanced form of the abnormalities found in anterolateral impingement. McCarroll and coworkers9 reported on four patients with chronic ankle pain after sprains who had meniscoid lesions on arthroscopy, all of whom improved after excision. in
10. Sequence of lateral ankle pain. ATFL, anterior talofibular ligament; AITFL, anterior inferior talofibular ligament ; CFL, calcaneofibular ligament.
Figure
Schonholtzll has described this meniscoid
sisting of
torn and fibrosed fibers of the
structure
as con-
capsule and liga-
ments, as well as chronic synovial tissue. Chen’ felt that a meniscoid attaching to the anterior talofibular ligament and extending into the lateral talomalleolar joint space is always seen after a sprained ankle. However, in our group of patients, only 4 of 31 (13%) patients with impingement findings had this discrete band of scar tissue. Histopathologic analysis on all patients failed to show any evidence of ligamentous tissues. Therefore, we feel the term &dquo;meniscoid lesion&dquo; should be abandoned since it is confusing and does not describe the abnormalities seen. The bands that Wolin and his colleagues&dquo; described were most likely composed of scar and synovium.
Although this paper has focused on anterolateral abnormalities, impingement lesions may also occur throughout the distal tibiofibular joint, posterolaterally or medially. These latter forms of impingement occur less frequently in our experience and are probably associated with a different mechanism of injury.’ Use of the distractor is usually necessary for visualizing posterolateral impingement and can be very beneficial when debriding about the anterior or posterior tibiofibular joint as well. Anterolateral impingement of the ankle is suspected clinically, but ultimately diagnosed and treated arthroscopically. Since there is at present no good clinical test to diagnose soft tissue impingement, the exact incidence of anterolateral impingement following ankle sprain is not known. It is likely that many patients with this problem get better with conservative treatment and never undergo arthroscopy for diagnosis. In the future, better diagnostic capabilities may allow us to calculate the incidence of patients with this problem who actually require surgery. Our long-term results suggest that arthroscopic treatment is successful in relieving the pain and disability caused by this disorder in a high percentage of patients whose symptoms have failed to respond to conservative measures. Most
446
patients treated with arthroscopic debridement of the lateral gutter were able to return to their previous levels of work and sports, despite the previous failure of prolonged conservative therapy (2 years in the series). Successful treatment requires an accurate diagnosis with a work-up that excludes other causes of chronic ankle pain. Because of the variety of different conditions that may cause chronic sprain pain, we prefer to label the patients described in this paper as having &dquo;anterolateral impingement of the ankle&dquo; and believe the more general term &dquo;chronic sprain pain&dquo; should be discarded.
ACKNOWLEDGMENT The authors thank Dennis Kassimian, MD, Department of Pathology, Valley Presbyterian Hospital, Van Nuys, California, for his assistance with the photomicrographs.
REFERENCES 1
2
3 4
5
Balduini FC, Tetzlaff J Historical perspectives on injuries of the ligaments of the ankle Clin Sports Med 1 3-12, 1982 Bray TJ, Endicott M, Capra SE Treatment of open ankle fractures Immediate internal fixation versus closed immobilization and delayed fixation Clin Orthop 240 47-52, 1989 Chen Y-C Arthroscopy of the ankle joint, in Wantanabe M (ed) Arthroscopy of Small Joints Tokyo, Igaku-Shoin, 1985, p 116 Ferkel RD Ankle arthroscopy, in An Illustrated Guide to Small Joint Arthroscopy Andover, MA, Dyonics, Inc , 1989 Ferkel RD, Fischer SP Progress in ankle arthroscopy Clin Orthop 240
210-220,1989 6 Ferkel RD, Karzel RP, Del Pizzo W, et al. Arthroscopic treatment of anterolateral impingement of the ankle Orthop Trans 14 249, 1990 7 Guhl J Soft tissue synovial pathology, in Ankle Arthroscopy Pathology and Surgical Techniques Thorofare, NJ, Slack Publishing, 1988, pp 93135 8 Maehlum S, Daljord OA Acute sports injuries in Oslo A one-year study Br J Sports Med 18 181-185, 1984 9 McCarroll JR, Schrader JW, Shelbourne KD, et al Meniscoid lesions of the ankle in soccer players Am J Sports Med 15 255-257, 1987 10 Meyer JM, Hoffmeyer P, Savoy X High resolution computed tomography in the chronically painful ankle sprain Foot Ankle 8 291-296, 1988 11 Shonholtz GJ Arthroscopic Surgery of the Shoulder, Elbow, and Ankle Springfield, IL, Charles C Thomas, 1987, p 69 12 Smith RW, Reischl SF Treatment of ankle sprains in young athletes Am : 465-471, 1986 J Sports Med 14 13 Taillard W, Meyer JM, Garcia J, et al The sinus tarsi syndrome Int Orthop 5 117-130,1981 14 Waller JF Hindfoot and midfoot problems of the runner, in Mack RP (ed) Symposium on the Foot and Leg in Running Sports St Louis, CV Mosby, 1982, pp 64-71 15 Wolin I, Glassman F, Sideman S Internal derangement of the talofibular component of the ankle Surg Gynecol Obstet 91 193-200, 1950
DISCUSSION Bert R. Mandelbaum, MD, Los Angeles, California: Residual problems after ankle sprains-such as pain, functional
instability, loss of proprioception, and weakness-can occur in up to 50% of patients. Chronic ankle pain after ankle sprain can be a difficult entity to diagnose and treat. Specific diagnosis and appropriate therapeutic intervention is essential to return the patient to work or sports activity. Doctors Ferkel and colleagues retrospectively evaluated 31 patients with chronic ankle pain and the anterolateral impingement syndrome. This report comes in parallel with others that present the concept of anterocapsular impingement in a total of well over 60 patients. Bartolozzi and Mandelbaum described soft tissue impingement in 21 patients in 1987. This entity was called &dquo;anterocapsular impingement.&dquo; A similar study was done by Martin and Baker at the Hughston Clinic. In all of these studies there were rigid inclusion criteria and subjective to objective preoperative and postoperative rating scales. These studies in concert conclude that this entity is a hypertrophic and scarred capsule in association with fibrous scarring of the ligaments resulting from an inversion ankle sprain. This then results in a dynamic impingement syndrome. There are several unanswered questions that remain. If this group of patients with soft tissue impingement is small, relative to all ankle sprains, then what specific pathoanatomical or pathomechanical details lead to a relentless chronic ankle pain? This study further defines the anatomical, pathoanatomical, and mechanical details of these entities. There are several important points that need to be stressed for patients with chronic ankle pain. A management algorithm must be established first. All patients with chronic ankle pain must have that pain defined with a precise subjective pain and symptom rating scale. Meticulous physical examination, followed by plain and stress films, is essential to differentiate instability from functional instability. Differential diagnosis must be established, including increased ligamentous laxity, osteochondral fractures, chondral lesions, osteophytes, osteochondrophytes, peroneal subluxation, sinus tarsi syndromes, avascular necrosis, and fractures. The use of an imaging technique such as MRI is essential not only to define what the specific lesion is, but, more importantly, what it is not. Patients must be given a specific diagnosis, and inclusion criteria must be met. At least 2 months of conservative management must ensue prior to
recommending surgery.
At arthroscopy it is imperative to define normal anatomy and to differentiate it from any abnormal anatomy. If there is any abnormal anatomy, what must be determined is how it relates to the dynamic impingement. Resection of soft tissue, osteochondral, or chondral tissue must be done with care and concern. A rigorous postoperative protocol and rehabilitation program is essential for full return to activity for this patient population.
Van
Nuys,
California
care.’ While most ankle sprains apparently heal without
ABSTRACT
sequelae after conservative therapy, a recent study of basketball players who had ankle sprains found that 50% had residual symptoms, with 15% symptomatic enough to compromise their playing performance.&dquo; Studies of ankle injuries emphasize that the most common mechanism of ankle injury is plantar flexion/inversion, resulting in injury to the lateral ligamentous complex of the ankle in over 90% of the cases.1 Not surprisingly, therefore, chronic lateral ankle pain after ankle sprain is much more common than chronic medial pain. To appreciate abnormalities in the lateral gutter of the ankle, it is necessary to understand the normal anatomy of
We studied 31 patients (17 females, 14 males; average age, 34) with more than 2 years of followup who had chronic anterolateral ankle pain following inversion injury. All had failed to respond to at least 2 months of conservative treatment and had negative stress radiographs to rule out instability. On physical examination, tenderness was localized to the anterolateral corner of the talar dome. Magnetic resonance imaging was the most useful diagnostic screening test, showing synovial thickening consistent with impingement in the anterolateral gutter. At an average of 24 months after injury, all patients underwent ankle arthroscopy, which showed proliferative synovitis and fibrotic scar tissue in the lateral gutter, often with associated chondromalacia of the talus. Operative arthroscopic treatment consisted of partial synovectomy with debridement of scar tissue from the lateral gutter. Postoperatively, patients walked with crutches allowing weightbearing as tolerated. Average return to sports was 6 weeks. Histopathologic analysis performed on the resected tissue showed synovial changes consistent with chronic inflammation. Results of treatment after at least 2 year followup were 15 excellent, 11 good, 4 fair, and 1 poor. Since there are several distinct causes of chronic ankle pain, we prefer to call this problem "anterolateral impingement of the ankle" and believe the term "chronic sprain pain" should be discarded.
this
The borders of the lateral gutter include the talus
sectional view demonstrates that the lateral gutter space extends from anterior to posterior between the fibula and talus (Fig. 3). The etiology of chronic lateral pain after an inversion injury of the ankle is often elusive, particularly in patients whose ankles are stable on examination and in stress radiographs. Wolin and colleagues&dquo; in 1950 described nine patients with persistent pain and swelling over the anterolateral aspect of the ankle several weeks to months after an inversion sprain. Arthrotomy of the ankle in these patients revealed a mass of hyalinized connective tissue extending into the joint from the anteroinferior portion of the talofibular ligament. They labelled this tissue a &dquo;meniscoid&dquo; lesion because it looked like a torn meniscus in the knee. They felt that disability resulted from entrapment of this lesion between the fibula and talus. Excision of the scar tissue relieved the symptoms in all cases. More recently, W aller14 identified a group of patients with &dquo;anterolateral corner compression syndrome,&dquo; which he believed resulted in pain
Ankle
sprains are among the most frequently observed inin athletics, with one recent large survey showing a 16% incidence of these injuries in athletes seeking medical *Presented at the 15th annual meeting of the AOSSM, Traverse
area.
medially, the fibula laterally, and the tibia with the tibiofibular ligament superiorly. Anteriorly, the lateral gutter is bordered by the anterior talofibular, calcaneofibular, and anterior inferior tibiofibular ligaments (Fig. 1). Posteriorly, the border includes the posterior talofibular, calcaneofibular, and posterior inferior tibiofibular ligaments (Fig. 2). A cross-
juries
Michigan, June 22,1989 t Address correspondence and reprmt requests to Richard Southern California Orthopedic Institute, 6815 Noble Avenue,
Orthopedic Institute,
City,
D Ferkel, MD, Van Nuys, CA
91405 440
441
along the anteroinferior border of the fibula and the anterolateral talus. His patients had valgus heels with pronated feet, and he believed this was a synovial compression syndrome dome.
or
chondromalacia of the lateral wall of the talar
Subsequently, there have been few references to this lesion began to share their findings from the arthroscopic management of chronic ankle sprains. In this paper, we report on the diagnosis and arthroscopic treatment of a group of patients with persistent lateral ankle pain after an inversion injury. We have labelled this problem &dquo;anterolateral impingement of the ankle&dquo; to distinguish it from other causes of chronic ankle pain. until surgeons
MATERIALS AND METHODS
Approximately 2000 patients at the Southern California Orthopedic Institute were treated for ankle sprains between 1983 and 1989. A diagnosis of anterolateral impingement was made in 43 patients (2%), all of whom underwent ankle arthroscopy. This was 25% of the 170 ankle arthroscopies performed by surgeons in our group from June 1984 to April 1989. We excluded 12 patients who had an associated fracture or who had less than 24 months of postoperative followup, resulting in a group of 31 patients whom we then studied retrospectively. Patient records and operative videotapes were reviewed for all patients. Ankle range of motion, stability, swelling, and tenderness were evaluated at follow-up examination. Each patient was also interviewed and asked questions about the present status of the ankle. An objective ankle rating scale (reported by Bray and coworkers2) was used to assign a numerical rating to each patient (Table 1). Patients were also asked to rate their ankles subjectively. The patient group consisted of 17 females and 14 males.
Figure 2.
Posterior borders of the lateral
gutter.
Figure 3. Cross-section through area of lateral gutter. The average age was 34, with a range from 16 to 74. There 19 injuries to the right ankle and 12 to the left ankle. All patients had sustained a previous &dquo;sprain&dquo; to their ankles, with 17 patients giving a history of plantar flexion/ inversion and 14 patients unsure as to the position of the ankle at the time of injury. Six of the patients had multiple previous sprains prior to the most recent major event. Fifteen patients injured their ankles at work, 11 in sports activities, and 5 had other sources of injury. Five patients had previous surgery on their ankles: removal of bone spur or bone fragment (two), Evans procedure (one), repair of a torn anterior talofibular ligament (one), and tarsal tunnel release (one). The most common presenting history was that of a prior ankle sprain followed by chronic persistent ankle pain with ambulation, weakness, and frequently a sensation of giving way. Physical examination revealed localized moderate to were
Figure 1. Anterior borders of the lateral gutter. (From Ferkel and Fischer,5 with permission.)
442
TABLE 1
Scoring for evaluation of anklesa
°
Total subtracted from 100 points: 90-100, excellent; 75-89, good; 50-74, fair; less than 50, poor.
tenderness of the anterolateral gutter of the ankle. Patients typically had normal or only slightly limited ankle motion. Any patients with inversion or anterior laxity of the ankle were not considered to have anterolateral impingement and were excluded from the study. Care was taken to distinguish pain in the lateral gutter of the ankle joint from pain in the area of the sinus tarsi. If the patient appeared to be tender in both areas, the sinus tarsi was injected with a local anesthetic. If injection of the sinus tarsi relieved the symptoms, the diagnosis was not considered to be anterolateral impingement. Plain radiographs were uniformly negative for previous fracture, widening of the ankle mortise, or significant degenerative changes. All of the patients had stress radiographs of the ankle, which were negative for instability. Three patients had magnetic resonance imaging (MRI), which showed increased soft tissue in the lateral gutter (Fig. 4). Two patients had weakly positive bone scans that showed increased uptake in the region of the distal tibia and fibula. With the exception of the MRI scans, the imaging studies were most helpful in excluding other causes of persistent pain such as osteochondral fracture, arthritis, or instability. All of the patients underwent prolonged conservative therapy with varying combinations of physical therapy (100%), nonsteroidal antiinflammatory drugs (100%), immobilization (50%), and steroid injections (62%) before undergoing definitive surgical management. The indications for arthroscopic surgery were a positive history for ankle sprain with subsequent chronic pain and tenderness in the lateral gutter severe
MRI scan showing scar tissue (low-intensity signal) in the lateral gutter of the ankle. Legend: tal, talus; fb, fibula;
Figure 4.
ataf, anterior talofibular ligament. was refractory to conventional treatment modalities in patients with otherwise negative workups. Arthroscopic surgery was performed on all patients in this study at an average of 24 months (range, 3 to 120) after injury. Techniques of the arthroscopic procedure have been detailed previously’ and will not be repeated here. Although we frequently use an ankle distractor during arthroscopy,
that
we
do not recommend
use
of the distractor for all
cases
of
suspected impingement. In some cases, use of the distractor makes visualization of the lateral gutter more difficult, since it tends to put the lateral gutter structures on stretch and compress the space. Generally in impingement cases, the procedure is begun without the distractor, which can be added subsequently if it appears that this will be of benefit. Examination of the entire ankle joint is performed arthroscopically in a systematic fashion. Patients with impingement syndrome have abnormalities that are confined primarily to the lateral side, usually consisting of synovitis and scar tissue and possibly with associated chondromalacia of the talar dome (Fig. 5). Debridement of the hypertrophic soft tissue is performed, as is chondroplasty of the talus, if necessary. In some patients, a meniscoid band is identified and excised (Fig. 6). Care must be taken not to excise the anterior talofibular ligament. Occasionally patients will also have associated synovitis in the distal tibiofibular joint and surrounding anterior tibiofibular ligament; sometimes this is best seen with the distractor. Postoperatively, the patient is placed in a compression
443
appeared inflamed
or hemorrhagic, and had a firmer and elastic consistency than is normally seen with other forms of synovitis (Fig. 7). Twenty patients (64%) had adhesive bands of scar tissue in the lateral gutter in addition to the synovial hypertrophy (Fig. 8). Sixteen patients (51% ) had chondromalacia of the anterolateral talar dome, usually Grades I or II, and occasionally of the distal tibia. Four
more
Figure 5. Arthroscopic visualization of hypertrophic soft tisin lateral gutter. (Reprinted with permission from Dyonics,
sue
Inc.4)
Figure 7. Hemorrhagic synovitis in lateral gutter of right ankle.
Figure 6. Debridement of soft tissue is performed arthroscopically. (Reprinted with permission from Dyonics, Inc.4) dressing and allowed weightbearing as tolerated with crutches. Crutches are discontinued after the lst week and rehabilitation is begun. Return to sports is allowed when the patient is asymptomatic, usually after 6 weeks. ’
RESULTS
Findings at surgery patients were noted to have hypertrophied, inflamed synovium at the time of operation. The synovium usually All
Figure 8. Resection of fibrotic scar band (double arrows) in lateral gutter using band cutter. Talus is marked by single arrow.
444
of the ankle were recorded. All patients were contracted for subjective followup at an average of 33.5 months
patients ( 13 % ) had well-developed bands of scar tissue which were similar to the meniscoid lesions first described by
bility
Wolin et aL 15 These bands extended from the anterior border of the lateral gutter to the posterior border, running freely through the lateral talofibular articulation. Three patients had anterior tibial osteophytes.
postoperatively (range, 24 to 66 months). Using the modified Weber ankle scoring scale from Bray and coworkers,2patients were rated as: 15, excellent; 11, good; 4, fair; and 1, poor. Twenty-nine of 31 patients returned to the same level of physical activity as prior to injury. Four patients did not return to their previous level of sports activities; one of these patients, however, attributed this to a subsequent back injury. The one poor result in a patient occurred early in the series. The patient had pain in the lateral ankle and was treated arthroscopically for anterolateral impingement. Her symptoms initially resolved but recurred 6 months postoperatively. At that time she was noted to have tenderness in the sinus tarsi, and her symptoms temporarily improved after an injection of lidocaine in the sinus tarsi region. She subsequently underwent an open operation with excision of the sinus tarsi, and her symptoms completely resolved. At 3 years after surgery she was asymptomatic. Four patients had fair results. All of these patients had work-related injuries. Three of the four had Grade II chon-
Pathologic findings Histologic analyses were performed on all patients with impingement syndrome. Moderate synovial hyperplasia with subsynovial capillary proliferation was seen in all cases. Also noted in many of the patients were hyaline cartilage degenerative change and fibrosis. These findings were consistent with a chronic inflammatory process (Fig. 9). Clinical evaluation All patients were examined in followup at least 3 months postoperatively, and tenderness, range of motion, and sta-
dromalacia of the talus at the time of surgery. All of these
patients complained of mild constant pain in the ankle and were unable to compete fully in sports activities but had minimal difficulties with the activities of daily living. Two of the patients in this group complained of a sensation of instability in their ankles. Both of these patients had initially done well after surgery but had deterioration of their results at 56 and 45 months, with a sense of increasing instability. In one of these cases, the patient had sustained a repeat injury to the ankle at the time of deterioration. The remaining 26 patients had excellent or good results. They were fully functional at work and in sports. Most had no pain or only minimal pain, which did not require analgesics, after activity. None had a significant loss of plantar flexion or dorsiflexion following arthroscopy. Two returned successfully to collegiate-level athletic activity. Reoperation was required in only one patient; we believe this patient was initially misdiagnosed as having anterolateral impingement and ultimately required excision of the sinus tarsi. No other complications were noted in this group of patients. DISCUSSION
Figure 9. Photomicrographs of resected soft tissue in impingement syndrome. A, synovial hyperplasia with subsynovial capillary proliferation (x100; H&E). B, hyaline cartilage demonstrating degenerative changes (x100; H&E).
This study describes anterolateral impingement syndrome, which can be a cause of chronic lateral ankle pain and disability following a plantar flexion/inversion injury to the ankle. In patients with chronic ankle pain after ankle sprain that is unresponsive to conservative therapy, several causes for the pain must be considered. In addition to chronic instability, pain may be due to osteochondral lesions of the talus, calcific ossicles beneath the malleoli, peroneal subluxation/dislocation or tear, tarsal coalition, subtalar joint dysfunction, or degenerative joint disease. Sinus tarsi syndrome must be differentiated from an impingement problem.l3 We feel that anterolateral impinge-
445
ment may occur occasionally with sinus tarsi syndrome. The exact relationship of these two entities is not clear, but
dysfunction may be the underlying problem. Occasionally, a patient will have pain in both the lateral gutter and subtalar areas and the origin of the pain cannot be determined, even with selective xylocaine injections. Presently, we are simultaneously performing arthroscopy on the ankle and subtalar regions to localize the diagnosis and treatment in this patient group. As more cases are done, a better understanding of this problem will evolve. Radiographic studies have not proven to be useful in diagnosing anterolateral impingement of the ankle, but they subtalar
may be very useful in
ankle
diagnosing other causes of chronic Stress pain. radiographs should be done if persistent
instability
is
suspected. Likewise,
a
recent
study by Meyer
and coworkers1° has demonstrated the value of high-resolution computerized tomography in the diagnosis of chronically painful ankle sprain. They found avulsed intraarticular or juxtaarticular fragments of traumatic origin that were not readily apparent on standard radiographs of 13 patients. A careful clinical examination and selected diagnostic studies should enable the examiner to exclude other causes of chronic ankle pain. Unfortunately, anterolateral impingement cannot be readily diagnosed with conventional imaging tests.
MRI may assist in the diagnosis in some cases, but has also been associated with false-negative results in our patients. Presently, we are developing different coils and planes of imaging to demonstrate the impingement abnormalities more clearly. In addition, a technique of cine MRI is being studied to better understand the ankle in motion. We believe the anterolateral impingement process begins when an inversion sprain tears the anterior talofibular and anterior inferior tibiofibular ligament, occasionally with an accompanying tear of the calcaneofibular ligament. Although the ligament injury is not severe enough to cause chronic instability, repetitive motion may lead to inflammation in the area(s) of the healing ligament(s) with resultant synovitis and formation of scar tissue. As this mass of tissue and synovium increases in size, impingement of the tissue mass between the talus, tibia, and fibula may cause increased irritation and pain, and further increase in inflammatory tissue. The end result is chronic lateral ankle pain’
(Fig. 10). The soft tissue present appears to be primarily synovial origin. Guhl’ has suggested that relatively mild sprains with minimal capsular tearing may result in an intraarticular hematoma that is only slowly reabsorbed. The blood may then be absorbed by the synovium in the lateral gutter and lead to a reactive synovitis. Four of the patients in our study also had meniscoid bands noted at surgery. These have been described by several authors 7,9,11,15 and probably represent a more advanced form of the abnormalities found in anterolateral impingement. McCarroll and coworkers9 reported on four patients with chronic ankle pain after sprains who had meniscoid lesions on arthroscopy, all of whom improved after excision. in
10. Sequence of lateral ankle pain. ATFL, anterior talofibular ligament; AITFL, anterior inferior talofibular ligament ; CFL, calcaneofibular ligament.
Figure
Schonholtzll has described this meniscoid
sisting of
torn and fibrosed fibers of the
structure
as con-
capsule and liga-
ments, as well as chronic synovial tissue. Chen’ felt that a meniscoid attaching to the anterior talofibular ligament and extending into the lateral talomalleolar joint space is always seen after a sprained ankle. However, in our group of patients, only 4 of 31 (13%) patients with impingement findings had this discrete band of scar tissue. Histopathologic analysis on all patients failed to show any evidence of ligamentous tissues. Therefore, we feel the term &dquo;meniscoid lesion&dquo; should be abandoned since it is confusing and does not describe the abnormalities seen. The bands that Wolin and his colleagues&dquo; described were most likely composed of scar and synovium.
Although this paper has focused on anterolateral abnormalities, impingement lesions may also occur throughout the distal tibiofibular joint, posterolaterally or medially. These latter forms of impingement occur less frequently in our experience and are probably associated with a different mechanism of injury.’ Use of the distractor is usually necessary for visualizing posterolateral impingement and can be very beneficial when debriding about the anterior or posterior tibiofibular joint as well. Anterolateral impingement of the ankle is suspected clinically, but ultimately diagnosed and treated arthroscopically. Since there is at present no good clinical test to diagnose soft tissue impingement, the exact incidence of anterolateral impingement following ankle sprain is not known. It is likely that many patients with this problem get better with conservative treatment and never undergo arthroscopy for diagnosis. In the future, better diagnostic capabilities may allow us to calculate the incidence of patients with this problem who actually require surgery. Our long-term results suggest that arthroscopic treatment is successful in relieving the pain and disability caused by this disorder in a high percentage of patients whose symptoms have failed to respond to conservative measures. Most
446
patients treated with arthroscopic debridement of the lateral gutter were able to return to their previous levels of work and sports, despite the previous failure of prolonged conservative therapy (2 years in the series). Successful treatment requires an accurate diagnosis with a work-up that excludes other causes of chronic ankle pain. Because of the variety of different conditions that may cause chronic sprain pain, we prefer to label the patients described in this paper as having &dquo;anterolateral impingement of the ankle&dquo; and believe the more general term &dquo;chronic sprain pain&dquo; should be discarded.
ACKNOWLEDGMENT The authors thank Dennis Kassimian, MD, Department of Pathology, Valley Presbyterian Hospital, Van Nuys, California, for his assistance with the photomicrographs.
REFERENCES 1
2
3 4
5
Balduini FC, Tetzlaff J Historical perspectives on injuries of the ligaments of the ankle Clin Sports Med 1 3-12, 1982 Bray TJ, Endicott M, Capra SE Treatment of open ankle fractures Immediate internal fixation versus closed immobilization and delayed fixation Clin Orthop 240 47-52, 1989 Chen Y-C Arthroscopy of the ankle joint, in Wantanabe M (ed) Arthroscopy of Small Joints Tokyo, Igaku-Shoin, 1985, p 116 Ferkel RD Ankle arthroscopy, in An Illustrated Guide to Small Joint Arthroscopy Andover, MA, Dyonics, Inc , 1989 Ferkel RD, Fischer SP Progress in ankle arthroscopy Clin Orthop 240
210-220,1989 6 Ferkel RD, Karzel RP, Del Pizzo W, et al. Arthroscopic treatment of anterolateral impingement of the ankle Orthop Trans 14 249, 1990 7 Guhl J Soft tissue synovial pathology, in Ankle Arthroscopy Pathology and Surgical Techniques Thorofare, NJ, Slack Publishing, 1988, pp 93135 8 Maehlum S, Daljord OA Acute sports injuries in Oslo A one-year study Br J Sports Med 18 181-185, 1984 9 McCarroll JR, Schrader JW, Shelbourne KD, et al Meniscoid lesions of the ankle in soccer players Am J Sports Med 15 255-257, 1987 10 Meyer JM, Hoffmeyer P, Savoy X High resolution computed tomography in the chronically painful ankle sprain Foot Ankle 8 291-296, 1988 11 Shonholtz GJ Arthroscopic Surgery of the Shoulder, Elbow, and Ankle Springfield, IL, Charles C Thomas, 1987, p 69 12 Smith RW, Reischl SF Treatment of ankle sprains in young athletes Am : 465-471, 1986 J Sports Med 14 13 Taillard W, Meyer JM, Garcia J, et al The sinus tarsi syndrome Int Orthop 5 117-130,1981 14 Waller JF Hindfoot and midfoot problems of the runner, in Mack RP (ed) Symposium on the Foot and Leg in Running Sports St Louis, CV Mosby, 1982, pp 64-71 15 Wolin I, Glassman F, Sideman S Internal derangement of the talofibular component of the ankle Surg Gynecol Obstet 91 193-200, 1950
DISCUSSION Bert R. Mandelbaum, MD, Los Angeles, California: Residual problems after ankle sprains-such as pain, functional
instability, loss of proprioception, and weakness-can occur in up to 50% of patients. Chronic ankle pain after ankle sprain can be a difficult entity to diagnose and treat. Specific diagnosis and appropriate therapeutic intervention is essential to return the patient to work or sports activity. Doctors Ferkel and colleagues retrospectively evaluated 31 patients with chronic ankle pain and the anterolateral impingement syndrome. This report comes in parallel with others that present the concept of anterocapsular impingement in a total of well over 60 patients. Bartolozzi and Mandelbaum described soft tissue impingement in 21 patients in 1987. This entity was called &dquo;anterocapsular impingement.&dquo; A similar study was done by Martin and Baker at the Hughston Clinic. In all of these studies there were rigid inclusion criteria and subjective to objective preoperative and postoperative rating scales. These studies in concert conclude that this entity is a hypertrophic and scarred capsule in association with fibrous scarring of the ligaments resulting from an inversion ankle sprain. This then results in a dynamic impingement syndrome. There are several unanswered questions that remain. If this group of patients with soft tissue impingement is small, relative to all ankle sprains, then what specific pathoanatomical or pathomechanical details lead to a relentless chronic ankle pain? This study further defines the anatomical, pathoanatomical, and mechanical details of these entities. There are several important points that need to be stressed for patients with chronic ankle pain. A management algorithm must be established first. All patients with chronic ankle pain must have that pain defined with a precise subjective pain and symptom rating scale. Meticulous physical examination, followed by plain and stress films, is essential to differentiate instability from functional instability. Differential diagnosis must be established, including increased ligamentous laxity, osteochondral fractures, chondral lesions, osteophytes, osteochondrophytes, peroneal subluxation, sinus tarsi syndromes, avascular necrosis, and fractures. The use of an imaging technique such as MRI is essential not only to define what the specific lesion is, but, more importantly, what it is not. Patients must be given a specific diagnosis, and inclusion criteria must be met. At least 2 months of conservative management must ensue prior to
recommending surgery.
At arthroscopy it is imperative to define normal anatomy and to differentiate it from any abnormal anatomy. If there is any abnormal anatomy, what must be determined is how it relates to the dynamic impingement. Resection of soft tissue, osteochondral, or chondral tissue must be done with care and concern. A rigorous postoperative protocol and rehabilitation program is essential for full return to activity for this patient population.
