The Specific Anatomical Morphology of Lateral Ankle Ligament: Qualitative and Quantitative Cadaveric based Study

OBJECTIVE

The accurate understanding in morphological features of the lateral ankle ligaments is necessary for the diagnosis and management of ankle instability and other ankle problems. The purpose of this study was to evaluate the anatomical morphology and the attachment areas of lateral ligament complex of ankle joint based on the cadaveric study.

METHODS

Fifty-four fresh frozen cadaveric ankles were dissected to evaluate the lateral ankle ligaments. Each ligament was separated into two or three small bundles. In the investigated footprint areas, acrylic colors were used as a marker point to locate specific areas of ligament bundle attached to the bone. The Image J software was used to measure and analyze the sizes of the specific footprint areas to achieve descriptive statistical analysis.

RESULTS

The double bands of anterior talofibular ligament (ATFL) were found as a major type in the present study with 57.41% (31 of 54 ankles) while the single band of ATFL was observed in 42.59% (23 of 54 ankles). The attachment sizes of the ATFL, posterior talofibular ligament (PTFL) and calcaneofibular ligament (CFL) were evaluated into two areas; proximal and distal attachments. The average of proximal or fibular part of ATFL, PTFL and CFL were 85.06, 134.27, 93.91 mm2 respectively. The average of distal part of ATFL, PTFL and CFL were 100.07, 277.61, 249.39 mm2 respectively.

CONCLUSION

Considering the lateral ankle ligament repaired or reconstruction especially using arthroscopy, the precise understanding in specific detail of the lateral ankle ligament may help both diagnose and select the appropriate treatment for solving the ankle problems. These observations may help the surgeon to perform the surgical procedure for determining the appropriate techniques and avoid complication to patients.

Anatomical Study of Stabilizing Structures of the Extensor Carpi Ulnaris Tendon Around the Wrist

PURPOSE

The sixth dorsal extensor compartment is a relatively common site of stenosing tenosynovitis in the upper extremity, but the exact location of stenosis is not fully understood. The objective of this study was to investigate the detailed anatomy of structures surrounding the extensor carpi ulnaris (ECU) tendon around the wrist.

METHODS

Fifty fresh human cadaveric wrists were used for gross observation and morphology measurements of the sixth dorsal compartment and the ECU subsheath. An additional 13 wrists were used for histological examination. We evaluated the morphology of supporting structures in 3 regions: the ulnar groove (zone I), the ulnar styloid process (zone II), and the triquetrum (zone III).

RESULTS

The fibro-osseous tunnel comprising the ulnar groove and the overlying subsheath (zone I) stabilized the ECU tendon, and the subsheath had thin membranous collagen fibers attached to the periosteum. We consistently found the distal extension of ECU subsheath (zone II), which connected the ulnar styloid process and the dorsal radioulnar ligament. Variations in the length of the distal extension increased with the forearm in pronation. Collagen fiber thickness around the ECU tendon in zone II was greater than that of zone I. In zone III, the overlying extensor retinaculum and septa, which were composed of thick circumferential collagen structures, supported the ECU tendon by attaching to the triquetrum on both sides of the ECU tendon. We found the presence of an ulnar septum of the sixth compartment attached to the triquetrum in 84% of dissected wrists.

CONCLUSIONS

The ECU tendon was supported by the ECU subsheath, which had thin and elastic collagen fibers over the ulnar groove. Distal extension of the subsheath and surrounding radial and ulnar extensor retinaculum septa attached to the triquetrum provided thicker supporting structures.

CLINICAL RELEVANCE

Stenosing ECU tenosynovitis may occur not only in the ulnar groove but also in the more distal ulnar styloid process and triquetrum areas.

Effect of Bone Resection on Posterior Talofibular Ligament Integrity for Posterior Ankle Impingement Syndrome: A Cadaveric Study

Purpose

The purpose of this study was to evaluate the attachment areas of the posterior talofibular ligament (PTFL) on the posterolateral tubercle of the talus and the remaining PTFL attachment areas after consequential bony excision.

Methods

Thirty fresh cadaveric ankles were dissected to study the proximal and distal attachment of the PTFL and separated the PTFL into anterior and posterior bundles. The description of the PTFL footprint and the anatomic landmarks from the surrounding structures were analyzed during consequential posterolateral bony excision.

Results

The average PTFL dimension was 26.11 mm (length), 7.65 mm (width), and 1.82 mm (thickness). The footprint area of the PTFL on the talar site consists of the posterior bundle (76.82%) and the anterior bundle (23.18%). If posterolateral tubercle excision was stayed up to a line of a bottom of the flexor hallucis longus (FHL) groove, at least 89% of the PTFL can be preserved.

Conclusion

The posterior bundle of the PTFL is the main bundle on the talar footprint area. To maintain the majority of the attachment of the PTFL, the resection of the posterolateral process could be performed to the bottom of the FHL tendon groove. If resection reaches to the posterior articular cartilage, less than 50% of the PTFL will be preserved. Understanding the footprint of the PTFL plays a key role in posterior ankle impingement surgery.

Clinical Relevance

This study provides guidance for resection of the posterolateral tubercle of the talus and a portion of the PTFL attachment for posterior ankle impingement syndrome. Too much resection of the tubercle may cause instability symptoms.

The comprehensive review of the neurovascular supply of the ankle joint: clinical implications

The rupture of ligament in the lateral part of ankle joint is a common injury and can lead to chronic ankle instability and lead to ankle osteoarthritis. Ankle arthroscopy is considered as a standard option to treat various ankle problems due to the need for only minimal incisions and fewer complications when compared to open surgery. However, there are complications associated with arthroscopic surgery e.g. damage to the anatomical structures around the portal placement areas. The present review provides anatomical knowledge of the superficial and deep neurovascular structures in the ankle region. These structures are important when ankle surgery is performed in order to avoid any intraoperative injury and prevent any complication following surgery.

The distribution pattern of the dorsal cutaneous nerves of the foot and its clinical implications

Iatrogenic injury to subcutaneous nerves on the dorsum of the foot is an established risk factor during the surgical procedures resulting in postoperative pain, sensation loss and painful neuroma. Previous studies have reported on the distribution pattern of the superficial peroneal, deep peroneal and sural nerves (SNs) and their branches with various classifications about specific populations. The purpose of the present study was to evaluate the distribution pattern and classification of the nerves on the dorsum of the foot and analyze the location of these nerves into five zones with clinical implications. Fifty-four lower limbs of fresh frozen cadavers were used in the present study. The anatomical patterns of the superficial peroneal, deep peroneal, SN and their branches were classified into eight, two and five patterns respectively. Type VI pattern, a classic distribution pattern of the superficial peroneal nerve was the most frequent type with a prevalence of 13 limbs (25.00%). In Zone 5, where the arthroscopic portal placements for the first metatarsophalangeal joint arthrodesis, 29 limbs (55.77%) showed three nerve branches located in this zone. The results of the present study provide anatomical knowledge that may help the surgeon to choose the appropriate treatment for their patients and reducing the rate of complications in surgery.