Stand-alone anterior lumbar interbody fusion (ALIF) provides the opportunity to avoid supplemental posterior fixation. This may reduce morbidity and complication rate, which is of special interest in patients with reduced bone mineral density (BMD). This study aims to assess immediate biomechanical stability and radiographic outcome of a stand-alone ALIF device with integrated screws in specimens of low BMD. Eight human cadaveric spines (L4-sacrum) were instrumented with SynFix-LR™ (DePuy Synthes) at L5/S1. Quantitative computed tomography was used to measure BMD of L5 in AMIRA. Threshold values proposed by the American Society of Radiology 80 and 120 mg CaHa/mL were used to differentiate between Osteoporosis, Osteopenia, and normal BMD. Segmental lordosis, anterior and posterior disc height were analysed on pre- and postoperative radiographs (Fig 1). Specimens were tested intact and following instrumentation using a flexibility protocol consisting of three loading cycles to ±7.5 Nm in flexion-extension, lateral bending, and axial rotation. The ranges of motion (ROM) of the index level were assessed using an optoelectronic system. BMD ranged 58–181mg CaHA/mL. Comparison of pre- and postoperative radiographs revealed significant increase of L5/S1 segmental lordosis (mean 14.6°, SD 5.1, p < 0.001) and anterior disc height (mean 5.8mm, SD 1.8, p < 0.001), but not posterior disc height. ROM of 6 specimens was reduced compared to the intact state. Two specimens showed destructive failure in extension. Mean decrease was most distinct in axial rotation up to 83% followed by flexion-extension. ALIF device with integrated screws at L5/S1 significantly increases segmental lordosis and anterior disc height without correlation to BMD. Primary stability in the immediate postoperative situation is mostly warranted in axial rotation. The risk of failure might be increased in extension for some patients with reduced lumbar BMD, therefore additional posterior stabilization could be considered. For any figures or tables, please contact the authors directly.
Single Photon Emission Computed Tomography – Computed Tomography (SPECT-CT) combines metabolic information with an exact anatomical localization. We hypothesised that diagnostic infiltration with a local anaesthetic of a painful hindfoot or midfoot joint showing 99mTc-DPD-uptake in SPECT-CT, leads to a positive OA pain response.
Proximally-coated non-cemented tapered femoral stems have demonstrated excellent long-term clinical results. However, there is sparse literature reporting the incidence of failure of osteointegration in patients with this stem design. The aim of this study is to report this incidence and identify factors which may increase its risk. 206 elective primary total hip arthroplasties were performed consecutively with a single stem design over a three-year period. All patients were evaluated clinically and radiographically. Radiographic parameters were analyzed for any potential risk factors that may predispose to failure of osteointegration. Three of 206 hips failed to osteointegrate and subsequently underwent revision surgery, for an incidence of 1.5%. The average time to revision was 1.2 years. The presenting complaint was persistent pain and radiographs revealed a progressive linear lucency at the proximal implant-bone interface in all three patients. Each patient had been implanted with a large-sized stem that had achieved a diaphyseal fit radiographically. This cohort had a statistically lower canal-flare index (p <
0.05) when compared to the rest of the study group. At the time of surgery, all stems were found to be loose and were easily removed. Failure of osteointegration in this type of stem is an uncommon but serious complication that may necessitate revision surgery. Risk factors predisposing to a failure to osteointegrate are a mismatch between the patient’s proximal femoral geometry and the stem, specifically a large stem in a Dorr type C femur, leading to a diaphyseal rather than a metaphyseal wedge.
We report good tolerance of high posology long term administration in documented osteoarticular indications if yeast colonization is properly monitored, and eradication rates are comparable to those reported in infections with susceptible bacteria.