Orthopaedic surgery is a practical surgical specialization field, the exit exam for registrars remains written and oral. Despite logbook evaluation and surgical work-based assessments, the question remains: can registrars perform elective surgery upon qualification? In South Africa, obstacles to elective surgical training include the trauma workload, financial constraints, fellowships and the Covid pandemic. In hip and knee arthroplasty, new approaches like the direct anterior approach (DAA) and robotic-assisted knee surgery also contributed to the dilution of cases available for registrar training. There are concerns that orthopaedic registrars do not perform enough cases to achieve surgical proficiency.

Review of the last 4 years of registrar logbooks in hip and knee arthroplasty surgery performed in a single tertiary academic hospital in South Africa. We included all primary total hip replacements (THR), total knee replacements (TKR) and hemiarthroplasties (HA) done for neck of femur (NOF) fractures between 1 April 2019 and 30 March 2023. Differentiation between registrar assisting, registrar performing with consultant supervision and registrar performing independent surgery was done.

990 hip arthroplasties (472 Primary THR, 216 NOF THR, 302 NOF HA) and 316 Primary TKR were performed during the study period. In primary elective THR the posterior approach was dominant and used in 76% of cases. In NOF THA the DAA was dominant used in 98% of cases. Primary TKR robotic-assisted technologies was used in 27% (n=94) cases. Registrars as the primary surgeon were the highest in NOF THA at 70% of cases and the lowest performing TKR at 25%. During 3-month rotations, an average registrar performed 12 (2 TKR and 10 THR) and assisted in 35 (10 TKR and 25 THR) cases.

Despite the large number of arthroplasties operations being performed over the last 4-year period, the surgical cases done by registrars are below, the proposed minimal cases to provide surgical proficiency during their training period.

Total Shoulder Arthroplasty (TSA) is a solution to fixing shoulder complications and restoring normal shoulder functionality. Shoulder arthritis is one of the common indicators of TSA. Studies suggest that 15% and 7% of the total Rheumatoid Arthritis (RA) and Osteoarthritis (OA) patients respectively, in sub-Saharan Africa, have degenerated shoulders. These patients are implanted with a Total Shoulder Prosthesis (TSP). There are limited literature available on the morphometric features of African shoulders. Previous studies have indicated that differences in shoulder surface geometry of the European and African populations, exists. This study aims at identifying the structural differences of the humeral articulating surfaces between South African and Swiss data sets.

The South African data set included the Computerised Tomography (CT) scans of cadavers sourced from the University of Cape Town and the Swiss data set included the cadaver CT scans obtained from the SICAS Medical Image Repository. Sixty reconstructed models of humerus were generated from these scans of 30 (bilateral) healthy cadavers (15 South African and 15 Swiss) using Mimics®. The humeral articulating surfaces were separated from the shaft by performing in-silico surgery using SOLIDWORKS®, according to the guidelines provided orthopaedic surgeons. A Matlab code was generated to determine the superior-inferior (S-I) and the anterior-posterior (A-P) circular diameter and the peak points (PPs) of the articulating surfaces. The PPs were defined as the highest point on the articulating surface, which is most likely to be in contact with the glenoid.

The S-I diameter was found to be significantly greater (p<0.01) than the A-P diameter for both the data sets (average difference = 5.02mm). Both the average A-P and S-I diameter for the Swiss data set were significantly larger (p = 0.02 and p = 0.03) than the South African data set by 2.36 mm and 2.70 mm respectively. The PPs were found to lie at an off-set from the origin. in case of the Swiss data set the average PP lie on the superior-posterior (S-P) quadrant and for the South African data set the average PP was found to lie on the anterior-inferior (A-I) quadrant. The A-P variation on the position of PP was highly significant (p = 0.003).

The results obtained in this study sheds light on the observed morphological variations between the South African and Swiss data sets. The observed circular diameter values are similar to the literature. The observed results suggest that the average TSP needed for the Swiss data set would have been larger than the ones needed for the South African data set. PP is a novel feature which has not been studied extensively. The fact that the average Swiss data set PP lie in the S-P quadrant might suggest that these humeral heads are more retroverted and superiorly tilted when compared to the South African data set. These morphometric variations can play a major role in post-TSA kinematics. The future scope of this study is to highlight other morphometric variations, if any, for the gleno-humeral articulating surfaces.