Changes in coronal alignment of the hip joint after medial opening wedge high tibial osteotomy.

PURPOSE: An observation was made by the senior author of this paper that patients reported changes in their hip function after a medial opening wedge high tibial osteotomy (MOHTO) for varus pattern osteoarthritis. Alignment changes at the hip after MOHTO have not been previously documented. This study assesses coronal alignment changes at the hip after MOHTO. METHODS: We retrospectively analysed pre- and post-operative lower limb alignment radiographs of patients who underwent MOHTO. The medial proximal tibial angle (MPTA) and mechanical axis deviation (MAD) were measured to assess the alignment changes created by the MOHTO. The coronal alignment changes at the hip were evaluated using the mechanical greater trochanter angle (MGTA). RESULTS: 29 osteotomies in 27 patients were included in this study. Results showed MOHTO created alignment changes at the hip. A positive correlation was found between the size of the correction at the knee and the subsequent changes at the hip. The change in the MGTA had a stronger correlation with the MAD than with the change in MPTA (r = 0.684 vs. 0.585). It was found that age, weight, height and BMI had no significant influence on these correlations. CONCLUSIONS: Increased correction by the MOHTO lead to increased change in the coronal alignment of the hip. These changes are likely to result in an alteration in the weight bearing portion of the femoral head and the function of the abductors and we recommend assessing the hip joint as part of pre-operative planning. LEVEL OF EVIDENCE: Prognostic level IV.

Comparison of Exeter stem offset size for total hip arthroplasty between males and females: A retrospective series of 780 hips.

Background: Many orthopaedic surgeons use a 'standard' stem offset length, typically 37.5 mm and 44 mm for females and males respectively, in total hip arthroplasty. With increasingly personalized surgery, 'standard' one-size-fits-all stem lengths may be outdated. This study aims to test whether pre-operative templating affects stem length choice and whether 'standard' stem sizes are therefore outdated. Methods: We performed a retrospective chart review of all total hip arthroplasty patients using Stryker's Exeter cemented femoral hip system in our centre between 2016 and 2020. Demographic and surgical data were collected. Data from surgeons who templated pre-operatively were compared to data from those who did not. Results: 780 patients were included (309 male, 471 female), average age 71.4 years (range 23-96). We found a significant difference between male and female offset lengths; more males had an offset length of 44 mm and more females had an offset length of 37.5 mm (p = 0.004). Among surgeons who did not template pre-operatively, 20.6% of female patients and 10.3% of male patients had other 'non-standard' offset lengths. Among surgeons who did template pre-operatively, the proportion of both female and male patients who had other 'non-standard' offset lengths was significantly higher (43.1% and 23.4%, respectively p < 0.05). Conclusions: The difference between templating and non-templating surgeons' stem choice revealed significant individual variability between males and females. 'Standard' offset lengths for males and females were still used in the majority of our cohort. However, with the emergence of mainstream robotic arthroplasty, we feel that pre-operative templating has become a minimum standard.

A Study Investigating Whether BMI Is Associated With Acetabular Bone Size: Big Bones or a Big Myth?

Background There is a common conception held by patients with a high body mass index (BMI) that they have "big bones". Some people hold the assumption that their weight is attributed to larger bone stock rather than adipose tissue. It was the suspicion of the surgeons at our unit that this is often not the case. We therefore conducted a study investigating if there is any association between BMI and acetabular bone size. Methods We conducted a retrospective chart review of all patients undergoing total hip arthroplasty using the Trident acetabular system from Stryker at our tertiary level 1 trauma centre between September 2016 and August 2020. Patient demographic and surgical data were collected, and the association of BMI, height, and weight, with acetabular cup size was investigated using Pearson's correlation coefficient and chi-square test for independence. Results A total of 418 patients were included in this study (52.4% female; age: 20-93 years; mean age: 62.51 years), with a mean BMI of 29.55 kg/m2(range: 14.95-52.32 kg/m2). A weak positive association between BMI and cup size, which was statistically significant (r = 0.107; n = 418; p = 0.02). The chi-square test for independence was used to study the association between obesity and cup size (large vs small), which demonstrated no significant difference (p = 0.08). There was a moderately strong positive association between height and cup size (r = 0.551; n = 418; p < 0.01). There was a weak positive association between weight and cup size, which was statistically significant (r = 0.355; n = 418; p < 0.01). Conclusion Our study suggests that there is indeed a weakly positive linear association between BMI and cup size among total hip arthroplasty patients. This effect was, however, more significant for height and weight, and there was no significant association between obese and non-obese groups with small versus large cup size implanted. We therefore conclude that clinically there is no significant relationship between obesity and acetabular bone size and that the "big bones" claim is indeed fallacious.

A technique for marking oncological breast tissue specimens.

With new breast conserving oncological surgical techniques, accurate identification of specimen margins is important to allow for the re-excision of margins. The accurate identification of margins is crucial is the success of the patients treatment if further margins are required. NHS Breast Screening Programme (NHSBSP) guidelines recommend the excised specimen is labelled accurately to correctly identify the margins and allow for X-ray examination. This method has been proven to be cheap, it uses equipment and materials readily available in the operating theatre. Furthermore, if any of the methods fails as there is more than one way to identifying your margins. For example if a clip were to fall off, the type/length of suture and the orientation on the board will still allow you to identify the correct margin. If the sample was to fall off the board, the sutures and clips will still allow the pathologist to orientate the sample. In summary this method is easy to apply, logical and uses equipment readily available within the theatre, i.e. silk sutures, and the needle protection board. It ensures all relevant radiological and surgical criteria are met for enabling orientation of the specimen when removed from the breast tissue. It is an easily taught technique that is easy to remember. A national survey showed a lack and wide variation of specimen orientation protocols. (Volleamere et al., 2013) This technique could be used as the national standard for breast specimen marking and as a national marking system for the NHS.