Correlating Arthroscopic and Radiographic Findings of Deep Deltoid Ligament Injuries in Rotational Ankle Fractures

Abstract

Background: The deep deltoid ligament (DDL) is a key stabilizer to the medial ankle and ankle mortise and can be disrupted in ligamentous supination external rotation type IV (LSER4) ankle fractures. The purpose of this study was to define the medial clear space (MCS) measurement on injury mortise radiographs that corresponds with complete DDL injury. Methods: A retrospective record review at a level 1 hospital was performed identifying patients with LSER4 ankle fractures who underwent arthroscopy and open reduction internal fixation. Chart reviews provided arthroscopic images and operative reports. Complete DDL injury was defined as arthroscopic visualization of the posterior tibial tendon (PTT). Inability to completely visualize the PTT was defined as a partial DDL injury. MCS was measured on injury mortise radiographs. Eighteen subjects met inclusion criteria. Results: Twelve subjects had complete and 6 subjects had partial DDL injury based on arthroscopic findings. Patients with complete DDL injury and those with partial DDL injury had injury radiograph MCS ranging from 5.5 to 29.9 mm and 4.0 to 5.0 mm, respectively. All patients with MCS ≥5.5 mm on injury radiographs had complete DDL injury and all patients with MCS ≤5.0 mm on injury radiographs had partial DDL injury. Conclusion: Complete DDL injury was found on injury ankle mortise radiographs as MCS widening of ≥5.5 mm, which correlated with arthroscopic visualization of the PTT. Using this cutoff, surgeons can surmise the presence of a complete deltoid ligament injury, allowing for improved preoperative planning. Level of Evidence: Level III, retrospective comparative study.

A Preliminary Study to Assess the Relevance of Shear-Wave Elastography in Characterizing Biomechanical Changes in the Deltoid Ligament Complex in Relation to Ankle Position

“…The deltoid ligament plays a major role in limiting talar abduction, pronation, and external rotation, thus protecting the syndesmosis and the distal fibula. 2,5,8,19,41,43,49 Their combined injuries are therefore frequent. 34,51 Consideration of a DPTTL lesion associated with syndesmosis injury is important because it leads to external rotation of the tibiotalar joint, worsening the instability in favor of operative management.…”

“…In addition to the clinical examination or arthroscopic examination, 2,35 magnetic resonance imaging is the gold standard for imaging ankle ligaments. 37 Another cross-sectional imaging alternative is the computed tomographic scan, which has shown its usefulness in daily clinical practice.…”

“…48 Nevertheless, its injury should not be underestimated because it may cause instability, 27,34,40 residual pain, 25,27 acquired flatfoot deformity in the case of an associated injury to the spring ligament, 36,47 or even early osteoarthritis of the external tibiotalar joint. 16,25 Ligaments have 3 main functions 3,7,9,46 : (1) a stabilizing role for the joint, regardless of its position; (2) viscoelastic properties that allow it to adapt its intraligament tension according to the stresses applied; and (3) a kinesthetic and proprioceptive function. This last function is well known, and the postural stability rehabilitation after sprain has been demonstrated.…”

Arthroscopic Quantitative Measurement of Medial Clear Space for Deltoid Injury of the Ankle: A Cadaveric Comparative Study With Stress Radiography

“…7 A study of supination–external rotation type 4 ankle fracture reported that patients with arthroscopic evidence of partial deep DL injury had a radiographic MCS ranging from 4.0 to 5.0 mm on injury mortise view, and patients with complete deep DL injury had an MCS ranging from 5.5 to 29.9 mm. 1 In addition to deep DL injury, arthroscopy could be used to diagnose superficial DL disruption by passing a probe from the medial gutter around the anterior colliculus into the subcutaneous tissue, which cannot be accomplished with the use of stress radiography only.…”

“…First, the average age of cadaveric specimens is older than that of patients suffering from DL injuries with ankle fractures, which is a common bias for in vitro cadaveric specimens because of their limited availability. 1,7 Second, the technique for probing into the medial gutter for MCS measurement may be subject to intersurgeon variability, which may result in bias. In our study, the 2 operators were instructed to advance the probe gently without obvious damage to surrounding cartilage.…”