Proximal humerus fractures (PHF) are common, accounting for approximately 5% of all fractures. Approximately 30% require surgical intervention which can range from open reduction with internal fixation (ORIF) to shoulder arthroplasty (including hemiarthroplasty, total shoulder arthroplasty, (TSA) or reverse total shoulder arthroplasty (RTSA)). The aim of this study was to assess trends in operative interventions for PHF in an Australian population.

Data was retrospectively collected for patients diagnosed with a PHF and requiring surgical intervention between January 2001 and December 2020. Data for patients undergoing ORIF were extracted from the Medicare database, while data for patients receiving arthroplasty for PHF were obtained from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR).

Across the study period, ORIF was the most common surgical procedure for management of PHFs. However, since 2019, RTSA has surpassed ORIF as the most common surgical procedure to treat PHFs, accounting for 51% of operations. While the number of RTSA procedures for PHF has increased, ORIF and shoulder hemiarthroplasty has significantly reduced since 2007 (p < 0.001). TSA has remained uncommon across the follow-up period, accounting for less than 1% of all operations. Patients younger than 65 years were more likely to receive ORIF, while those aged 65 years or greater were more likely to receive hemiarthroplasty or RTSA.

While the number of ORIF procedures has increased during the period of interest, it has diminished as a proportion of overall procedure volume. RTSA is becoming increasingly popular, with decreasing utilization of hemiarthroplasty, and TSA for fracture remaining uncommon. These trends provide information that can be used to guide resource allocation and health provision in the future. A comparison to similar data from other nations would be useful.

In an effort to improve alignment in total knee arthroplasty (TKA), more recent prosthetic devices adapt computerised sculpting technologies based on preoperative MRIs to individualize surgical treatment. This is achieved by creating patient-specific surgical positioning guides for prosthetic alignment. Our study reports on the early clinical and functional outcomes and CT measured alignment of patients undergoing surgery with the Signature patient specific knee system.

We have reviewed the first one hundred patients selected to have a TKA using the patient specific knee system by a single surgeon over the last two years. Clinical and functional outcomes were assessed using the Western Ontario and McMaster Universities (WOMAC) index, the American Knee Society Scores (AKSS) and range of flexion at 6months. All data was analysed using a two tailed paired students t-test with statistical significance accepted at p<0.05. Post-operative CT scans were analysed to report on overall mechanical axial limb alignment, axial prosthetic tibial alignment, posterior tibial slope and femoral component rotation from the epicondylar axis.

Preoperative versus postoperative WOMAC scores for patients were 80.4 ± 2.2 and 45.2 ± 2.1 respectively. This was statistically significant at p=1.3×10–14. The AKSS pre- and postoperatively were 85.1 ± 4.6 and 151.9 ± 4.6 respectively with statistical significance reached at p = 1.3×10–13. Specifically, the pre- vs postoperative knee scores were 33.6 ± 2.8 and 75.1 ± 2.6 (p=3.9×10–12) while the function scores were 51.5 ± 2.8 and 75.8 ± 4 (p=3.4×10–7) respectively. Range of flexion preoperatively was 110.8 ± 2.8 while postoperatively was 122.1 ± 2.6 (p=0.0003). Postoperative CT scans revealed that the tibial axial alignment was 90.5 ± 7.7 degrees while the posterior tibial slope was 5.5 ± 0.3 degrees on average. In terms of femoral rotation, the epicondyllar axis was found to be 0.56 ± 0.1 degrees externally rotated with respect to Whiteside's line. The mechanical axis was 0.84 ± 0.1 on average. With all these measured parameters the number of outliers outside the accepted +/−3 degree range are small.

Our data demonstrates that the early results for knee replacements performed using the Signature patient specific jigs are very satisfactory delivering good clinical outcomes and an improved level of prosthetic alignment when compared to published data for standard instrumented knees.

The relationships between the transepicondylar axis (TEA), Whiteside's line(WL), and posterior condylar axis (PCA) are commonly used to determine the rotational alignment of the femur in total knee arthroplasty (TKA). It has been previously reported that may be gender differences in the rotational and mechanical anatomy of the distal femur1. The aim of our study was to examine the distal femur in a large number of patients to report on any gender differences within the group. The MRIs of a large cohort of prospectively chosen patients (n= 217) were examined retrospectively in order to determine the rotational femoral alignment. Varus/valgus relationship of their knees prior to prosthesis insertion was also examined. Measurements pertained to femoral rotation (relationships between WL, TEA and PCA) and varus/valgus alignment were calculated directly from MRI studies by a single observer. Gender differences were examined using an unpaired students t-test. Averages and standard deviations are reported to within two significant figures.

The posterior condylar axis was 2.6 ± 1.5 degrees relative to the transepicondylar axis and 91.8 ± 1.7 degrees relative to Whiteside's line. The varus to valgus ratio was 4.6 ± 5.9. Males in the group had a PCA of 2.4 ± 1.6 degrees relative to TEA compared to females in the group (2.8 ± 1.4 degrees). There was no significant difference between both groups (p=0.06). The PCA relative to WL was 92.1 ± 1.6 degrees for males compared to 91.6 ± 1.9 degrees for females with no significant difference between both groups (p=0.06). Finally, the varus to valgus ratio was 5 ± 5.7 for males compared to females (4.3 ± 6.2) with no statistical significance achieved between both groups (p=0.39).

Our results show that there is no significant difference in the rotational anatomy and varus/valgus alignment between men and women in a large cohort. Interestingly, the large standard deviation for values pertaining to femoral rotational anatomy (>3 degrees) suggest a significant degree of variability between patients. Thus, operative planning embracing our findings may prove to be of great clinical benefit by advocating individualising operative treatment in TKA surgery.