A larger radial tuberosity, and therefore a smaller radioulnar space, may cause mechanical impingement of the DBT predisposing to tear. We sought to investigate anatomic factors associated with partial DBT tears by retrospectively reviewing 3-T MRI scans of elbows with partial DBT tears and a normal elbow comparison group

3-T MRI scans of elbows with partial DBT tears and elbows with no known pathology were reviewed retrospectively by two independent observers. Basic demographic data were collected and measurements of radial tuberosity length, radial tuberosity thickness, radio-ulnar space, and radial tuberosity-ulnar space were made using simultaneous tracker lines and a standardised technique. The presence or absence of enthesophytes and the presence of a single or double DBT were noted.

26 3-T MRI scans of 26 elbows with partial DBT tears and 30 3-T MRI scans of 30 elbows without pathology were included. Basic demographic data was comparable between the two groups. The tear group showed statistically significant larger mean measurements for radial tuberosity length (24.3mm vs 21.3mm, p=0.002), and radial tuberosity thickness (5.5mm vs 3.7mm, p=<0.0001. The tear group also showed statistically significant smaller measurements for radio-ulnar space (8.2mm vs 10.0mm, p=0.010), and radial tuberosity-ulnar space (7.2mm vs 9.1mm, p=0.013). There was a statistically significant positive correlation between partial DBT tears and presence of enthesophytes (p=0.007) as well as between partial DBT tears and having two discrete DBTs rather than a single or interdigitating tendon (p=<0.0001).

Larger radial tuberosities, and smaller radio-ulnar and radial tuberosity-ulnar spaces are associated with partial DBT tears. This may be due to chronic impingement, tendon delamination and consequent weakness which ultimately leads to tears. Enthesophytes may be associated with tears for the same reason. Having two discrete DBTs that do not interdigitate prior to insertion is also associated with partial tears.

A retrospective review of 57 military patients undergoing ankle arthroscopy between 1999 and 2011 was performed. A case-note review of medical records was undertaken pertaining to military role, ankle injury sustained, mechanism, presenting symptoms and their duration. Arthroscopic findings were compared to findings on radiographs and MRI scans. At first presentation 23 patients had features of arthritis on radiographs. We found MRI was both highly sensitive (97.7%) and specific (93.4%) in detecting osteochondral defects (OCD). 16 of the patients had evidence of osteochondral injury. All OCDs picked up on MRI were confirmed at arthroscopy. Ankle injury may not be a benign injury in military personnel, with over half of these young patients having radiological features of osteoarthritis at presentation. We found MRI an effective tool for identifying occult injuries not seen on radiographs. Lateral ligament injury with associated gutter scarring can be successfully treated with arthroscopic debridement. This suggests pseudoinstability rather than a true mechanical instability as the main cause for patient's symptoms in this cohort.