Acromial morphology has been implicated as a risk factor for unidirectional posterior shoulder instability. Studies utilising plain film radiographic landmarks have identified an increased risk of posterior shoulder dislocation in patients with higher acromion positioning. The aims of this study were to develop a reproducible method of measuring this relationship on cross sectional imaging and to evaluate acromial morphology in patients with and without unidirectional posterior shoulder instability.

We analysed 24 patients with unidirectional posterior instability. These were sex and age matched with 61 patients with unidirectional anterior instability, as well as a control group of 76 patients with no instability. Sagittal T1 weighted MRI sequences were used to measure posterior acromial height relative to the scapular body axis (SBA) and long head of triceps insertion axis (LTI). Two observers measured each method for inter-observer reliability, and the intraclass correlation coefficient (ICC) calculated.

LTI method showed good inter-observer reliability with an ICC of 0.79. The SBA method was not reproducible due suboptimal MRI sequences. Mean posterior acromial height was significantly greater in the posterior instability group (14.2mm) compared to the anterior instability group (7.7mm, p=0.0002) as well when compared with the control group (7.0mm, p<0.0001). A threshold of 7.5mm demonstrated a significant increase in the incidence of posterior shoulder instability (RR = 9.4).

We conclude that increased posterior acromial height is significantly associated with posterior shoulder instability. This suggests that the acromion has a role as an osseous restraint to posterior shoulder instability.

Ideberg-Goss type VI/AO F2(4) glenoid fossa fractures are a rare and complex injury. Although some advocate non-operative management, grossly displaced glenoid fossa fractures in the young patient may warrant fixation. Current approaches still describe difficulty with access of the entirety of the glenoid, particularly the postero-superior quadrant.

We present 2 cases of Ideberg-Goss type VI/AO F2(4) glenoid fossa fractures treated with fixation through a novel “Deltoid Takedown” approach, which allows safe access to the whole glenoid with satisfactory clinical results at 5 and 7 years respectively.

Aim

Two different techniques to release subscapularis during total shoulder replacement (TSR) have been described (tenotomy and osteotomy) with no consensus as to which is superior. In this study we review the clinical outcomes of a sequential series of patients in whom a TSR for primary osteoarthritis had been performed using either technique at our institution. Subscapularis function was tested using a new graded belly press test, a modification of the traditional belly press test which is described for the first time here.

Background

The purpose of this retrospective study was to examine the functional outcomes of patients treated for isolated fracture of the greater tuberosity (GT) and to determine how their outcomes were affected by fracture pattern, treatment choices, associated shoulder injuries, the post fixation displacement of GT fragment and the time delay between injury and fixation.

Isolated Greater Tuberosity (GT) fractures were described as separate entities from proximal humeral fractures more than 100 years ago. However, there is limited literature available about the functional outcome of the two different types of GT fractures: avulsed and comminuted

To compare functional outcomes of the 2 different types of Greater Tuberosity fractures; simple and comminuted and to determine how these outcomes were affected by associated injuries such as shoulder dislocation and rotator cuff tear. We also looked at the acceptable post fixation displacement of GT fracture and when to consider it mal-reduction (malunion due to over or under reduction) and the acceptable time frame to delay the fixation and still get satisfactory results.

We looked at Greater Tuberosity fractures of the humerus in Waikato Hospital between 1999–2009. Radiographs were reviewed by senior Author to classify them into simple and comminuted. Measurements were done by senior Author for post fixation displacement. Operative notes checked by the authors, when in doubt, double-checked by senior author. Outcome scores used: UCLA, ASES and oxford scores to compare functional outcome. We also measured the time off work and time on ACC (Physiotherapy), as well as period of follow up.

A total of 35 patients were included in the final analysis were treated operatively. Mean age of the patients was 51 years. M/F ratio was 3/2. Mechanism of injury was predominantly direct force applied to that shoulder. Shoulder dislocation was found in around 77% of patients. Methods of fixation included tension band wiring with or without screws, rotator cuff repair and one T-plate. Follow up time was shorter for simple comminuted fractures (22 v 44 weeks respectively). Outcome scores for patients who sustained simple fractures were slightly higher than those with comminuted fractures but the difference did not reach statistical significance. The groups with dislocation and rotator cuff tear did worse than the other groups in all aspects of the study. Post fixation displacement of GT of less than 5 mm led to a significantly better outcome than displacement of 5mm plus. Better results were obtained when the time between injury and operation was less than 2 weeks.

The comminuted group had similar functional outcome to the other group but required much longer follow up. Worse outcome should be expected with dislocation and rotator cuff tear associated with GT fracture. Satisfactory results relate to degree of displacement post fixation of <5 mm. Delay of fracture fixation of >2 weeks results in a less favourable outcome.