Functional evaluation of the 10-year outcome after modified Evans repair for chronic ankle instability

Treatment of lateral ankle instability with transfer of the extensor digitorum brevis muscle

Ankle sprains are the most common injuries sustained during sports and physical exercise. Treatment is usually conservative because most of these injuries heal without consequence. However, some injuries may be followed by chronic lateral pain and instability, and surgical stabilization is sometimes necessary. In select cases, there is little or no residual ligament or scar tissue remaining for late reconstruction. Proximal transfer of the origin of the extensor digitorum brevis muscle as a substitute for deficient ligament tissue can be used in these difficult cases. During the years 1971 to 1992, 13 ankles in 10 patients underwent surgery using the proximal extensor digitorum brevis muscle transfer method. At follow-up, all the ankles manifested functional stability and were stable with no clinical drawer sign. All had a normal range of motion in the ankle joint but showed a desired decreased supination range of motion throughout the hindfoot and ankle. The functional Karlsson scores were 84.5 +/- 18.8 before injury, 26.4 +/- 18.7 before surgery, and 83.6 +/- 18.7 at follow-up. Thus, the extensor digitorum brevis muscle transfer seems to be a useful alternative method of long-term ankle stabilization in these difficult chronic case; the results correlate well with a few other studies using this method.

Twenty-year results of the Evans operation for lateral instability of the ankle

Twenty-four patients (25 ankles), operated on using the static modification of the Evans tenodesis for lateral instability, were evaluated 19 to 21 years after surgery. Twelve of the patients (12 ankles) had excellent results, seven patients (eight ankles) had good results, three patients (three ankles) had fair results, and two patients (two ankles) had poor results. The subjective results had no clear correlation to the stress radiographs, which showed minor or moderate anterior talar translation in 10 ankles. Moreover, the difference between the surgically treated and the contralateral ankle was not significant. Static modification of the Evans tenodesis is recommended if an anatomic reconstruction of the lateral ligaments is not feasible (general laxity of joints, reoperation).

Complications of lateral ankle ligament reconstruction

Complications after ankle ligament reconstruction are infrequent, but present significant challenges to the treating orthopaedist. Local wound problems and nerve injuries may cause difficulty in the early postoperative period. Recurrent instability may be attributable to failure of the operation, poor rehabilitation, reinjury, or unrecognized predisposing factors. Postoperative stiffness of the subtalar and ankle joints frequently is reported after anatomic and nonanatomic tenodesis procedures and may cause significant morbidity. The current author reviews reported complications and treatment options in failed lateral ankle ligament surgery.

Fractures and fracture dislocations of the midfoot: occurrence, causes and long-term results

Etiology and outcome of 155 patients with midfoot fractures between 1972 and 1997 were analyzed to create a basis for treatment optimization. Cause of injuries were traffic accidents (72.2%), falls (11.6%), blunt injuries (7.7%) and others (5.8%). Isolated midfoot fractures (I) were found in 55 (35.5%) cases, Lisfranc fracture dislocations (L) in 49 (31.2%), Chopart-Lisfranc fracture dislocations (CL) in 26 (16.8%) and Chopart fracture dislocations (C) in 25 (16%). One hundred and forty eight (95%) of the midfoot fractures were treated operatively; 30 with closed reduction, 115 with open reduction, 3 patients had a primary amputation. Seven (5%) patients were treated non-operatively. Ninety seven (63%) patients had follow-up at an average of 9 (1.3-25, median 8.5) years. The average scores of the entire follow-up group were as follows: AOFAS - sum of all four sections (AOFAS-ET): 296, AOFAS-Midfoot (AOFAS-M): 71, Hannover Scoring System (HSS): 65, and Hannover Questionnaire (Q): 63. Regarding age, gender, cause, time from injury to treatment and method of treatment no score differences were noted (t-test: p>0.05). L, C or I showed similar scores and CL significantly lower scores (AOFAS-ET, AOFAS-M, HSS, Q). The highest scores in all groups were achieved in those fractures treated with early open reduction and operative fixation. Midfoot fractures, particularly fracture dislocation injuries, effect the function of the entire foot in the long-term outcome. But even in these complex injuries, an early anatomic (open) reduction and stable (internal) fixation can minimize the percentage of long-term impairment.

Outcome of the modified Broström procedure for chronic lateral ankle instability using suture anchors

The modified Broström procedure is an anatomic reconstruction of the lateral ankle ligaments. The present study evaluated twenty-two patients (mean age = 27.2 years) with chronic lateral ankle instability who underwent surgical repair of their lateral ankle ligaments using suture anchors as part of the modified Broström procedure. All surgeries were performed by the senior author (AK) on an outpatient basis. At a mean follow-up of 34.5 months (minimum of 18 months), twenty patients (91%) reported a good or excellent functional outcome as assessed by the Karlsson and Peterson ankle function scoring scale. One patient developed a superficial wound infection post-operatively that was eradicated with a course of oral antibiotics. Sixteen of the twenty-two patients were available for follow-up physical examination and stress radiographs. Fourteen of the sixteen patients had no evidence of instability on physical examination or on stress radiographs. One patient had diminished sensation in the superficial peroneal nerve distribution. Five of the sixteen patients had generalized ligamentous laxity; none of these patients had an excellent result, and they had lower "Overall Satisfaction" scores (P=0.013). We conclude that the use of suture anchors is a simple and effective adaptation of the modified Broström procedure, which results in a good or excellent outcome in the majority of patients with few complications.

A moment-based technique for the automatic spatial alignment of plantar pressure data

Plantar pressure measurements have many potential clinical applications in the field of orthopaedics. However, the only current routine clinical application of pedobarography is for the identification of high pressure zones in diabetic patients with neuropathy who are at risk from foot ulceration. For pedobarography to become a routine clinical tool in orthopaedics, a thorough knowledge of normal plantar pressure distributions would be required. To date, no large scale studies to define population norms have been conducted, probably because of the high cost associated with analysing large quantities of plantar pressure data. Plantar pressure distributions display a high step-to-step variation and, therefore, it is necessary to conduct multiple trials. Comparison between these trials is difficult, somewhat subjective, and slow, because it must be conducted manually. The present authors have developed a technique to align automatically the spatial components of a series of datasets. The technique then allows predefined parameters to be automatically extracted from the data, hence greatly reducing analysis time. The authors believe that not only does the technique make large scale studies economically viable but that it could also form the basis for expert systems for the diagnosis of foot pathologies and the prescription of orthoses.

Integrated pressure-force-kinematics measuring system for the characterisation of plantar foot loading during locomotion

Plantar pressure, ground reaction force and body-segment kinematics measurements are largely used in gait analysis to characterise normal and abnormal function of the human foot. The combination of all these data together provides a more exhaustive, detailed and accurate view of foot loading during activities than traditional measurement systems alone do. A prototype system is presented that integrates a pressure platform, a force platform and a 3D anatomical tracking system to acquire combined information about foot function and loading. A stereophotogrammetric system and an anatomically based protocol for foot segment kinematics is included in a previously devised piezo-dynamometric system that combines pressure and force measurements. Experimental validation tests are carried out to check for both spatial and time synchronisation. Misalignment of the three systems is found to be within 6.0, 5.0 and 1.5 mm for the stereophotogrammetric system, force platform and pressure platform, respectively. The combination of position and pressure data allows for a more accurate selection of plantar foot subareas on the footprint. Measurements are also taken on five healthy volunteers during level walking to verify the feasibility of the overall experimental protocol. Four main subareas are defined and identified, and the relevant vertical and shear force data are computed. The integrated system is effective when there is a need for loading measurements in specific plantar foot subareas. This is attractive both in clinical assessment and in biomechanics research.

The effects of ankle compliance and flexibility on ankle sprains

PURPOSE

The goal of this study was to examine the influence of changes in subtalar joint flexibility and compliance on ankle sprain occurrence.

METHODS

Muscle model driven simulations of 10 subjects performing the landing phase of a side-shuffle movement were performed. The passive flexibility or compliance of the subtalar joint was varied, and each subject-specific simulation was exposed to a set of perturbed floor conditions.

RESULTS

Increases in flexibility and compliance both led to an increase in the occurrence of excessive supination, while changes in flexibility had a greater influence. Changes in flexibility or compliance caused only small changes in the occurrence of excessive supination torques.

CONCLUSION

These results suggest that increased mechanical laxity does not directly cause an increase in sprain occurrence during side-shuffle movements.

Reliability of peroneal reaction time measurements

OBJECTIVE

The purpose of this study was to demonstrate the reliability of reaction time-measurements on a tilting platform under consideration of various influencing factors.

DESIGN

The peroneal reaction time of 30 healthy subjects was examined in an experimental study.

BACKGROUND

Peroneal reaction time measurements have been used to objectively evaluate functional instability of the ankle joint, but the reliability of the method has not been proven yet.

METHODS

The reaction time after sudden inversion of the ankle were determined by surface EMG.

RESULTS

The median latency of the peroneus brevis was 66 ms and that of the peroneus longus was 63 ms. No differences between male and female subjects and between left and right legs could be found. An increase of reaction time was caused by neuromuscular fatigue (P=0.033, for both the peroneus brevis and the peroneus longus). A decrease in reaction time resulted if the foot was held in 15 degrees of plantar flexion (P=0.0004 for the peroneus brevis, P=0.002 for the peroneus longus). The reliability was examined by circadian and by day-to-day measurements. The coefficient of correlation (Spearman's rho) between the peroneus brevis and days 1-5 was 0.67 (P=0.177) and for the peroneus longus 0. 00 (P0.999). The same results were obtained after the circadian measurements.

CONCLUSION

Determination of peroneal reaction time was proven as a reliable measurement method.

RELEVANCE

Reliability and validity are basic preconditions of a test to become accepted as a clinical measurement method. This paper demonstrates the reliability of measuring the peroneal reaction time. Thus, assuming validity, the peroneal reaction time measurement is justified as a clinical test.

Clinical and functional outcome after anatomic and nonanatomic ankle ligament reconstruction: Evans tenodesis versus periosteal flap

The present study investigated the effects of two different surgical procedures for the treatment of chronic ankle instability. Ten patients treated with an anatomic reconstruction using a periosteal flap were compared with a second group that received an Evans tenodesis. All patients were evaluated before and after surgery with clinical and radiographic examinations as well as dynamic pedobarography. Patient satisfaction and radiographic and functional results were comparable in both groups and revealed a good restoration of joint stability and gait symmetry. Our results indicate that both methods of ankle ligament reconstruction achieve a comparable clinical and functional outcome within 1 year after surgery.

Biomechanics of the unstable ankle joint and clinical implications

PURPOSE

The aim of this paper is to provide fundamental information about the biomechanics of the unstable ankle joint and to establish a rational for the daily clinic when dealing with patients in both, the acute and chronic unstable condition of the ankle joint complex.

METHODS

The problem of the unstable ankle joint is worked up by analyses of the basic anatomy and biomechanics followed by an overview of its clinical manifestation including a differential diagnosis.

RESULTS

The ankle joint and its surrounding ligaments represent a complex mechanical structure whose mechanical properties highly depend on ligament integrity. Recent in vitro studies have supported the hypothesis that, besides maintaining lateral ankle stability, the lateral ankle ligaments play a significant role in maintaining rotational ankle stability and in transferring movement between leg and foot. Instability of the ankle results from acute ligament injuries and may become chronic when complete ligament healing does not occur. Chronic instability syndrome may manifest with recurrent injuries with chronic lateral pain, tenderness, swelling, or induration with great difficulties in sports and daily activities. Symptomatic instability can be caused by mechanical instability with demonstrable instability, but it can be also present with no demonstrable instability. Impairment of ankle proprioception has been shown to be a major cause of symptomatic ankle instability. Other conditions may mimic ankle instability.

CONCLUSIONS

The cause of chronic functional instability is often not mechanical instability but impairment of ankle proprioception. A history of insecurity, instability, and giving way is far more important in diagnosis than the physical and radiographic examination. If surgical treatment is advised, anatomical reconstruction of the ankle ligaments is mandatory for fear of altering the biomechanics.