First-time anterior dislocation of the shoulder is associated with the development of recurrent instability. It is recognised that patients with recurrent instability often have osseous defects. Using 3D computerised tomography (3DCT) it is possible to quantify these defects. Whether these defects are present after the primary dislocation or occur progressively from multiple dislocations is unclear. We correlated the presence of Hill-Sachs lesions and anterior glenoid bone loss with evidence of recurrent dislocation and clinical outcomes.

78 patients were followed up for two years. All underwent a 3DCT within a week of injury. Standardised images of the humeral head and glenoid were produced. Using standardised digital techniques bone loss was measured.

39% of the patients developed further instability. Average Hill-Sachs circumferential length = 15.23%. Average Hill-Sachs surface area = 5.53%. The length and surface area of the Hill-Sachs lesions were significantly associated with further instability. (p=0.019 and p=0.003). Average en face glenoid surface area loss=1.30% with no association to instability (p=0.685). There was poor correlation between the size of the glenoid lesion and the size of the Hill-Sachs lesion.

Results showed that age and increasing size of the Hill-Sachs lesions result in a higher rate of instability. Interestingly glenoid bone loss was relatively low and did not predict recurrent instability. The size of the Hill-Sachs lesion does not have a linear relationship with glenoid bone loss. Further work defining the morphology of the Hill-Sachs lesion and its engagement with a glenoid defect is required.

Background: Several factors can alter a cements viscosity and hence it’s handling characteristics. An in vitro study was performed to ascertain whether anecdotal observations of differences in handling between batches of the same cement brand existed.

Methods: 3 batches of Simplex P Tobramycin (SPT), Refobacin Bone Cement (RBC), SmartSet GHV (SSG) and Palacos R+G (PRG) were tested. 6 replicates of each batch were vacuum mixed and their viscosity in relation to time was measured in laboratory conditions (50 ±5% humidity and 23 ±1°C) using a rheometer. 6 replicates of each batch had their handling characteristics examined after they were hand mixed in theatre conditions.

Results: Inter and intra-batch variability was seen in the viscosity of all brands of cements tested. Inter-batch calculations were influenced by high intra-batch viscosity variability. The viscosity of RBC cement was very similar to SSG, but significantly different to PRG (p = 0.01 at 5N and p = 0.009 at 40 N).

Interpretation: Our results suggest that in clinical practice extrinsic factors such as preparation conditions and methods probably play a more important role than the cements intrinsic variability. However, variability in handling and viscosity will exist in all brands of cement prepared in theatre conditions and the surgeon needs to be aware why they may act differently.

Historically, cemented THA femoral stems inserted in varus have yielded poor clinical results. Very few studies to date have addressed the question of the effects of varus alignment on uncemented stems. We have conducted a retrospective review of one hundred and twenty-five uncemented THA femoral stems implanted by a single surgeon from 1994 to 1999. Within this single surgeon group we were able to identify sixteen stems implanted in varus and thus proceeded to analyze the effect of varus alignment on functional outcome.

To assess functional and radiographic outcome of uncemented primary THA femoral stems implanted in varus.

After four-years of follow-up, there have been no radiographic or clinical problems associated with implanting uncemented femoral stems in varus.

Although it is not recommended to implant stems in varus, radiographic and clinical problems associated with implanting uncemented femoral stems in varus appear to be non-consequential.

Of the study sample, one hundred and sixteen hips were in neutral alignment as compared to sixteen varus hips. We could not show any significant difference in Harris Hip scores between the varus and non-varus hips (p> 0.5). No cases showed evidence of radiographic loosening, or subsidence (p=0.3) at four-year follow-up.

Retrospective radiographic review of one hundred and twenty-five uncemented primary THA femoral stems implanted by a single surgeon (now retired) from 1994 to 1999, using the Watson-Jones approach, identified sixteen femoral stems implanted in varus. These sixteen stems were matched 1:1 for demographics and preoperative diagnosis to a cohort of sixteen non-varus uncemented stems implanted by the same surgeon over the same study period. Functional outcome included Harris Hip score and range of motion at four-years postoperative. Radiographic signs of loosening and subsidence, defined as > 2mm, were measured. Varus alignment was defined as ≥ 5°. Paired t-tests were conducted on all outcome variables, p< 0.05 was considered statistically significant.

Study results suggest there to be no consequence of varus femoral alignment in uncemented stems. Patients will need to be followed for a longer duration to further examine the effects of varus implantation of unce-mented femoral stems.

A radiographic review of sixty-nine lateral closing wedge high tibial osteotomies and forty-two medial opening wedge osteotomies was conducted. Patellar height and tibial slope were measured. The Blackburne-Peel (BP) and Insall-Salvati (IS) ratios were used to measure patellar height. Our results show that 18.8% and 47.6% of the lateral closing wedge group had patella-infera (PI) according the the BP and IS ratios respectively. No opening-wedge cases demonstrated patella infera with either ratio. Tibial slope was found to be significantly more neutral in the closing wedge group versus the opening wedge (−2.2° vs. −7.28° respectively).

Patients undergoing HTO typically require a definitive arthroplasty procedure at an average of six years post-HTO. Total knee arthroplasty can be complicated by the presence of PI which compromises exposure and increases the risk of patellar tendon avulsion leading to suboptimal results. The current study compares the incidence of PI between lateral closing and medial opening wedge HTO’s.

Conversion of opening wedge HTO to TKA should have less technical challenge and improved outcomes as compared to lateral closing wedge HTO conversions. This is attributable to the absence of PI.

Of the closing wedge group, 18.8% and 47.6% were found to have PI according to the BP and IS ratios respectively. Of the opening wedge group there were no cases of PI found with either ratio. Tibial slope was found to be significantly more neutral in the closing wedge compared to the opening wedge group (−2.2° vs. −7.28° respectively).

The study cohorts were abstracted from surgeon records. Sixty-nine closing wedge and forty-two opening wedge HTO’s were identified. Lateral 30° flexion x-rays were measured for patellar height and tibial slope. Both the Blackburne-Peel (BP) and Insall-Salvati (IS) patellar height measurements were used.

From this data we can conclude that in our study population the incidence of PI in the opening wedge group was 0% thus negating the potential deleterious effects of PI at the time of knee arthroplasty.