The emergence of patient specific instrumentation has seen an expansion from simple radiographs to plan total knee arthroplasty (TKA) with modern systems using computed tomography (CT) or magnetic resonance imaging scans. Concerns have emerged regarding accuracy of these non-weight bearing modalities to assess true mechanical axis. The aim of our study was to compare coronal alignment on full length standing AP imaging generated by the EOS acquisition system with the CT coronal scout image.

Eligible patients underwent unilateral or bilateral primary TKA for osteoarthritis under the care of investigating surgeon between 2017 and 2022, with both EOS X-Ray Imaging Acquisition System and CT scans performed preoperatively. Coronal mechanical alignment was measured on the supine coronal scout CT scan and the standing HKA EOS.

Pre-operative lower limb coronal alignment was assessed on 96 knees prior to TKA on the supine coronal scout CT scan and the standing HKA EOS. There were 56 males (56%), and 44 right knees (44%). The mean age was 68 years (range 53-90). The mean coronal alignment was 4.7 degrees (SD 5.3) on CT scan and 4.6 degrees (SD 6.2) on EOS (p=0.70). There was a strong positive correlation of coronal alignment on CT scan and EOS (pearson

0.927, p=0.001). The mean difference between EOS and CT scan was 0.9 degrees (SD 2.4). Less than 3 degrees variation between measures was observed in 87% of knees. On linear regression for every 1° varus increase in CT HKA alignment, the EOS HKA alignment increased by 0.93° in varus orientation. The model explained 86% of the variability.

CT demonstrates excellent reliability for assessing coronal lower limb alignment compared to EOS in osteoarthritic knees. This supports the routine use of CT to plan TKA without further weight bearing imaging in routine cases.

The Exeter^™ V40 cemented polished tapered stem system has demonstrated excellent long-term outcomes. This paper presents a systematic review of the existing literature and reports on a large case series comparing implant fractures between the Exeter V40 series; 125 mm and conventional length stem systems.

A systematic literature search was performed adhering to PRISMA criteria. In parallel we performed a retrospective single centre study of Exeter^™ V40 femoral stem prosthetic fractures between April 2003– June 2020.

There are 25 reported cases of such prosthetic fractures confined to small case series and case reports within the literature. We report an additional 19 cases to the literature (mean age 66.3 ± 11.7 years; 12 female [63%]; body mass index 32.9 ± 5.9 kg/m²). The mean time from index procedure to fracture was 7.8 years (2.5–16.3, ±3.6). Exeter V40 stem fracture incidence was 0.27%. Incidence was significantly higher in 125 mm length stems compared to ≥150 mm length stems (1.26% vs 0.13%, respectively, p <0.001) and revision arthroplasty (1.209% vs 0.149%, p <0.001). When comparing different stem length cohorts, 125-mm short-stem were associated with stem body fractures (92% vs 29%, p = 0.0095), earlier time to fracture (6.2 vs 11.0 years, p = 0.0018), younger patient age at time of fracture (62.7 vs 72.6 years old, p = 0.037) and female sex (75% vs 43%, p = 0.33).

This case series in conjunction with the systematic review provides evidence stem morphology plays a role in femoral implant fracture. This complication remains rare, although we report a significantly higher incidence at up to 17 years follow-up than in the literature. As femoral geometries remain the same, increasing BMIs in THR patients should raise concern. Short 125 mm length Exeter V40 stems undoubtedly have a role in restoring anatomy and biomechanics in smaller femoral geometries, although the surgeon has to appreciate the higher risk of stem fracture and the associated predisposing factors which may necessitate meticulous surgical technique and planning.

Aims

The Exeter V40 cemented polished tapered stem system has demonstrated excellent long-term outcomes. This paper presents a systematic review of the existing literature and reports on a large case series comparing implant fractures between the Exeter V40 series; 125 mm and conventional length stem systems.

Background:

Lumbar intraspinal cysts (LICs) are rare incidental MRI findings in back pain. Their space-occupying nature make them plausible factors in both non-specific and radicular back pain.

Objectives

The goals of this study were: 1) to determine if high-fat diet (HFD) feeding in female mice would negatively impact biomechanical and histologic consequences on the Achilles tendon and quadriceps muscle; and 2) to investigate whether exercise and branched-chain amino acid (BCAA) supplementation would affect these parameters or attenuate any negative consequences resulting from HFD consumption.