The purpose of this study was to investigate the influence of surgical approach on femoral stem version in THA.

This was a retrospective database review of 830 THAs in 830 patients that had both preoperative and postoperative CT scans. All patients underwent staged bilateral THAs and received CT-based 3D planning on both sides. Stem version was measured in the second CT-scan and compared to the native neck axis measured in the first CT-scan, using the posterior condyles as the reference for both. Cases were performed by 104 surgeons using either a direct anterior (DAA, n=303) or posterior (PA, n=527) approach and one of four stem designs: quadrangular taper, calcar-guided short stem, flat taper and fit-and-fill. Sub-analyses investigated changes in version for low (≤5°), neutral (5–25°) and high (≥25°) native version subgroups and for the different implant types.

Native version was not different between approaches (DAA = 12.6°, PA = 13.6°, p = 0.16). Overall, DAA stems were more anteverted relative to the native neck axis vs PA stems (5.9° vs 1.4°, p<0.001). This trend persisted in hips with high native version (3.2° vs -5.3°, p<0.01) and neutral native version (5.3° vs 1.3°, p<0.001), but did not reach significance in the low native version subgroup (8.9° vs 5.9°, p=0.13). Quadrangular taper, calcar-guided, and flat taper stem types had significantly more anteversion than native for DAA, while no differences were found for PA.

Stems implanted with a direct anterior approach had more anteversion than those implanted with a posterior approach. The smaller surgical field, soft tissue tension and lack of a “tibial” vertical reference frame may contribute to this finding.

There is an increasing incidence of revision for periprosthetic joint infection. The addition of vancomycin to beta-lactam antimicrobial prophylaxis in joint arthroplasty may reduce surgical site infections, however, the efficacy and safety have not been established.

This was a multicenter, double-blind, superiority, placebo-controlled trial. We randomized 4239 adult patients undergoing joint arthroplasty surgery to receive 1.5g vancomycin or normal saline placebo, in addition to standard cefazolin antimicrobial prophylaxis. The primary outcome was surgical site infection at 90-days from index surgery. Perioperative carriage of Staphylococcus species was also assessed.

In the 4113 patients included in the modified intention-to-treat population, surgical site infections occurred in 72/2069 (3.5%) in the placebo group and 91/2044 (4. 5%) in the vancomycin group (risk ratio 1.28; 95% confidence interval 0.94 to 1.73; p value 0.11). No difference was observed between the two groups for primary hip arthroplasty procedures. A higher proportion of infections occurred in knee arthroplasty patients in the vancomycin group (63/1109 [4.7%]) compared with the placebo group (42/1124 [3.7%]; risk ratio 1.52; 95% confidence interval 1.04 to 2.23; p value 0.031). Hypersensitivity reactions occurred in 11 (0.5%) patients in the placebo group and 24 (1.2%) in the vancomycin group (risk ratio 2.20; 95% confidence interval 1.08, 4.49) and acute kidney injury in 74 (3.7%) patients in the placebo group and 42 (2.1%) in the vancomycin group (risk ratio 0.57; 95% confidence interval 0.39, 0.83). Perioperative Staphylococcus aureus carriage was detected in 1089/3748 (29.1%) of patients.

This is the first randomized controlled trial examining the addition of a glycopeptide antimicrobial to standard beta-lactam surgical antimicrobial prophylaxis in joint arthroplasty. The addition of vancomycin to standard cefazolin prophylaxis was not superior to placebo for the prevention of surgical site infections in hip and knee arthroplasty surgery.

The pelvis moves in the sagittal plane during functional activity. This can be detrimental to functional cup orientation. Increased pelvic mobility could be a risk factor for instability and edge-loading, in both flexion and/or extension. The aim of this study was to investigate how gender, age and lumbar spine stiffness, affects the number of patients at risk of excessive sagittal pelvic mobility.

Pre-operatively, 3428 patients had their pelvic tilt and lumbar lordotic angle (LLA) measured in three positions; supine, standing and flexed-seated. The pelvic rotation from supine-to-standing and from supine-to-seated was determined from the difference in pelvic tilt measurements between positions. Lumbar flexion was determined as the difference between LLA standing and LLA when flexed-seated. Patients were stratified into groups based upon age, gender, and lumbar flexion. The percentage of patients in each group with “at risk” pelvic rotation, defined by rotation ≥13° in a detrimental direction, was determined.

There was an increased incidence of “at risk” pelvic mobility with increasing age, and decreasing lumbar flexion. This was more pronounced in females. Notably, 31% of elderly females had “at risk” pelvic mobility. Furthermore, 38% of patients with lumbar flexion <20° had “at risk” pelvic mobility.

“At risk” pelvic mobility was more common in older patients and in patients with limited lumbar flexion. Additional stability, such as a dual mobility articulation, might be advisable in patient cohort. However, the majority of patients exhibiting “at risk” pelvic mobility were not older than 75, and did not have lumbar flexion <20°. This supports analysis of pelvic mobility on all patients undergoing THR.

Aims

The pelvis rotates in the sagittal plane during daily activities. These rotations have a direct effect on the functional orientation of the acetabulum. The aim of this study was to quantify changes in pelvic tilt between different functional positions.