Minimally Invasive Treatment of Chronic Ankle Instability: a Comprehensive Review

Allogeneic tendons in the treatment of malunited lateral malleolar avulsion fractures with chronic lateral ankle instability

BACKGROUND

The aim of this study is to report our institution's experience regarding the application of allogeneic tendons for the reconstruction of malunited lateral malleolar avulsion fractures with chronic lateral ankle instability.

METHODS

This retrospective study included 34 (34 ankles) patients surgically treated for malunited lateral malleolar avulsion fractures with chronic lateral ankle instability from January 2016 to December 2019. All patients underwent allogeneic tendon reconstruction. The pre- and postoperative American Orthopaedic Foot and Ankle Society (AOFAS) scores、Karlsson Ankle Functional Scores (KAFS) and visual analogue scale (VAS) scores were used to evaluate the functional recovery of the ankle joint. The final follow-up, based on radiographic assessment, including talar tilt and anterior talar translation, was performed to evaluate the stability of the postoperative ankle joints.

RESULTS

Thirty-two patients (32 ankles) returned for final clinical and radiologic follow-up at an average of 29 (range 24-35) months and 2 patients (2 ankles) were lost to follow-up. The preoperative talus inclination angle (13.6 ± 1.9°) and anterior displacement (9.6 ± 2.8 mm) were re-examined under X-ray and found to be reduced to 3.4 ± 1.2° and 3.8 ± 1.1 mm, respectively (p＜0.01). The AOFAS scores increased from 58.5 ± 4.0 to 90.9 ± 3.8 and the Karlsson scores improved from 52.2 ± 3.6 to 89.8 ± 4.5, which was obviously better and the difference was statistically significant (P < 0.01). The VAS scores were significantly reduced from a preoperative mean of 6.8 ± 1.0 to 2.8 ± 0.9 postoperatively (p＜0.01).

CONCLUSION

In this population and with this follow-up, the application of allogeneic tendons to treat malunited lateral malleolar avulsion fractures combined with chronic lateral ankle instability appeared safe and effective.

Clinical Results Following Conservative Management of Tarsal Tunnel Syndrome Compared With Surgical Treatment: A Systematic Review

Introduction

Posterior tarsal tunnel syndrome involves entrapment of the posterior tibial nerve as it travels in the groove posterior to the medial malleolus. Conventional wisdom dictates that patients with tarsal tunnel syndrome be treated with conservative treatment and medical management, with surgical options available for patients with refractory symptoms and good candidacy. Minimally invasive options for neuropathic entrapment syndromes have developed in recent years and may provide a therapeutic role in tarsal tunnel syndrome.

Objective

The present investigation provides a summary of the current state of knowledge on tarsal tunnel syndrome and a comparison between minimally invasive and surgical treatment options.

Methods

The literature search was performed in Mendeley. Search fields were varied until redundant. All articles were screened by title and abstract and a preliminary decision to include an article was made. A full-text screening was performed on the selected articles. Any question regarding the inclusion of an article was discussed by 3 authors until an agreement was reached.

Results

Most commonly tarsal tunnel syndrome is idiopathic. Other reported causes include post-traumatic, lipomas, cysts, ganglia, schwannomas, ganglia, varicose plantar veins, anatomic anomalies, and systematic inflammatory conditions. Several risk factors have been described including female gender, athletic participation, hypothyroidism, diabetes mellitus, systemic sclerosis, chronic renal failure, and hemodialysis use. A few recent studies demonstrate anatomic variants that have not previously been summarized. Three articles describe clinical outcomes after conservative treatment with acceptable results for first line treatment. Two primary articles report on the use of minimally invasive treatment for tarsal tunnel syndrome. Fourteen articles report on the clinical outcomes after surgical management.

Conclusion

Clinical understanding of tarsal tunnel syndrome has evolved significantly, particularly with regards to the pathoanatomy of the tarsal canal over the past twelve years. A few novel anatomic studies shed light on variants that can be helpful in diagnosis. Conservative management remains a good option that can resolve the symptoms of many patients. As more prospective cohorts and clinical trials are performed on minimally invasive options, pulsed radiofrequency and neuromodulation may evolve to play a larger role in the treatment of this condition. Currently, surgical treatment is only pursued in a very select group of patients with refractory symptoms that do not respond to medical or minimally invasive options. Surgical outcomes in the literature are good and current evidence is stronger than that for minimally invasive options.

An open-source OpenSim® ankle-foot musculoskeletal model for assessment of strains and forces in dense connective tissues

BACKGROUND

The ankle and foot are among the most critical load-bearing joints in the human anatomy. Anatomically accurate human body models are imperative to understanding the mechanics of injury and musculoskeletal disorders. A typical human ankle-foot anatomy consists of 25 DOFs, 112 dense connective tissues (DCTs) (92 ligaments, one capsule and 19 fasciae), 30 tendons, and 65 muscles. Existing models possess less than half of the DOFs and physiological elements. In this work, we have developed an ankle-foot joint complex musculoskeletal model for the OpenSim® platform by incorporating 24 degrees of freedom (DOF) comprising of 66 DCTs (46 ligaments, one 1 capsule and 19 fasciae), 30 tendons, and 65 muscles.

METHODS

Computed tomography (CT) data of human ankle joint-foot complex was segmented using Mimics ® (Version 17.0, Materialise, Belgium) to obtain models of the cartilages and bones of the ankle joint-foot complex. The position and resting lengths of the DCTs were attained from the MRI data and literature. Five joints, namely, tibiotalar, subtalar, chopart, tarsometatarsal (TMT), and metatarsophalangeal (MTP) joints and their joint axes were formulated to yield 24 DOFs. A forward simulation was carried out at each joint of the ankle-foot complex within their respective range of motions. The strains, instantaneous strain rates, and forces developed in the ligaments during the simulation were studied.

RESULTS

During plantar-dorsiflexion of the tibiotalar joint, the anterior tibio-talar ligament (aTTL) yielded the maximum strain compared to all other ligaments. Anterior tibio-fibular ligament (aTFL) experienced extreme strain during subtalar inversion. Hence, the coupled kinematics of subtalar inversion and plantar flexion are failure-prone activities for aTFL. The chopart, TMT, and MTP joints yielded maximum strains or forces for several bundles at the extremes of the range of motion. This signifies that rotations of these joints to their extreme range of motion are prone to failure for the bundles attached to the joint complex.

CONCLUSION

The results illustrate the potential application of the proposed OpenSim® ankle-foot model in understanding the ligament injury mechanism during sports activity and its prevention. Researchers can use the proposed model or customise it to study complex kinematics, understanding injury mechanisms, testing fixtures, orthosis or prosthesis, and many more in the domain of musculoskeletal research.