Aims

This study reports the ten-year wear rates, incidence of osteolysis, clinical outcomes, and complications of a multicentre randomized controlled trial comparing oxidized zirconium (OxZr) versus cobalt-chrome (CoCr) femoral heads with ultra-high molecular weight polyethylene (UHMWPE) and highly cross-linked polyethylene (XLPE) liners in total hip arthroplasty (THA).

This study reports the ten-year polyethylene liner wear rates, incidence of osteolysis, clinical outcomes and complications of a three-arm, multicentre randomised controlled trial comparing Cobalt-Chrome (CoCr) and Oxidised Zirconium (OxZr) femoral heads with ultra-high molecular weight polyethylene (UHMWPE) versus highly cross-linked polyethylene (XLPE) liners in total hip arthroplasty (THA).

Patients undergoing THA from four institutions were prospectively randomised into three groups. Group A received a CoCr femoral head and XLPE liner; Group B received an OxZr femoral head and XLPE liner; and Group C received an OxZr femoral head and UHMWPE liner. Blinded observers recorded predefined outcomes in 262 study patients at regular intervals for ten years following THA.

At ten years follow-up, increased linear wear rates were recorded in group C compared to group A (0.133 ± 0.21 mm/yr vs 0.031 ± 0.07 mm/yr respectively, p<0.001) and group B (0.133 ± 0.21 mm/yr vs 0.022 ± 0.05 mm/yr respectively, p<0.001). Patients in group C were associated with increased risk of osteolysis and aseptic loosening requiring revision surgery compared with group A (7/133 vs 0/133 respectively, p=0.007) and group B (7/133 vs 0/135 respectively, p=0.007). There was a non-significant trend towards increased liner wear rates in group A compared to group B (0.031 ± 0.07 mm/yr vs 0.022 ± 0.05 mm/yr respectively, p=0.128). All three groups were statistically comparable preoperatively and at ten years follow-up when measuring normalised Western Ontario and McMaster Universities Osteoarthritis Index(p=0.410), short-form-36 (p = 0.465 mental, p = 0.713 physical), and pain scale scores (p=0.451).

The use of UHMWPE was associated with progressively increased annual liner wear rates after THA. At ten years follow-up, this translated to UHMWPE leading to an increased incidence of osteolysis and aseptic loosening requiring revision THA, compared with XLPE. Femoral heads composed of OxZr were associated with a non-significant trend towards reduced wear rates compared to CoCr, but this did not translate to any differences in osteolysis, functional outcomes, or revision surgery between the two treatments groups.

This study reports the ten-year outcomes of a three-arm, multicentre randomised controlled trial comparing Cobalt-Chrome (CoCr) and Oxidised Zirconium (OxZr) femoral heads with ultra-high molecular weight polyethylene (UHMWPE) versus highly cross-linked polyethylene (XLPE) liners in total hip arthroplasty (THA).

Patients undergoing THA from four institutions were prospectively randomised into three groups. Group A received a CoCr femoral head and XLPE liner; Group B received an OxZr femoral head and XLPE liner; and Group C received an OxZr femoral head and UHMWPE liner. The outcomes of 262 study patients were analysed at ten years follow-up.

At ten years, increased linear wear rates were recorded in group C compared to group A (0.133 ± 0.21 mm/yr vs 0.031 ± 0.07 mm/yr respectively, p<0.001) and group B (0.133 ± 0.21 mm/yr vs 0.022 ± 0.05 mm/yr respectively, p<0.001). Patients in group C had increased risk of osteolysis and aseptic loosening requiring revision surgery compared with group A (7/133 vs 0/133 respectively, p=0.007) and group B (7/133 vs 0/135 respectively, p=0.007). There was a non- significant trend towards increased liner wear rates in group A compared to group B (0.031 ± 0.07 mm/yr vs 0.022 ± 0.05 mm/yr respectively, p=0.128). All three groups were statistically comparable preoperatively and at ten years follow-up from a clinical score perspective.

The use of UHMWPE was associated with progressively increased annual liner wear rates. At ten years follow-up, this translated to an increased incidence of osteolysis and aseptic loosening requiring revision, compared with XLPE. Femoral heads composed of OxZr were associated with a non-significant trend towards reduced wear rates compared to CoCr, but this did not translate to any differences in osteolysis, functional outcomes, or revision surgery between the two treatments groups.

Bertolotti first described articulation of the L5 transverse process with the sacrum as a cause of back pain in 1917. Since then little attention has been payed to these atypical articulations despite their high reported incidence.

Here we describe our early experience of surgical treatment and propose a validated CT based classification of lumbosacral segment abnormalities (LSSA).

400 lumbosacral CT scans were reviewed (NBT), a classification devised and incidence of abnormalities recorded. 40 patients were selected and 4 independent observers classified each scan. Case notes for all patients (C&V) who received steroid injections into or surgical excision of LSSAs were reviewed. Results as follows:

5 types of abnormality were identified.

Type 0 - normal

Type 1 - asymmetrical shortening of the iliolumbar ligament

Type 2 - transverse process of L5 within 2mm of the sacrum

Type 3 - diarthrodial joint (3A: no evidence of degeneration 3B: degenerative change)

Type 4 - transverse process and sacrum have fused

Type 5 - extends to L4

54.5% of patients had abnormalities. The kappa values for the intra-observer results were 0.69 to 0.88 and the inter-observer ratings gave a combined score of over 0.7 indicating substantial agreement.

Our CT classification of LSSAs is both straight forward to use and repeatable. The incidence of these abnormalities is higher in our population of CT scans compared to previous published series using plain radiographs. All patients treated with surgical excision of established articulations (Type 3A or above) reported good or excellent outcomes following excision.

Oxidised zirconium (OxZi) has been developed as an alternative bearing surface for femoral heads in total hip arthroplasty (THA). This study has investigated polyethylene wear, functional outcomes and complications, comparing OxZi and cobalt–chrome (CoCr) as part of a three-arm, multicentre randomised controlled trial. Patients undergoing THA from four institutions were prospectively randomised into three groups. Group A received a CoCr femoral head and highly cross-linked polyethylene (XLPE) liner; Group B received an OxZi femoral head and XLPE liner; Group C received an OxZi femoral head and ultra-high molecular weight polyethylene (UHMWPE) liner. At five years, 368 patients had no statistically significant differences in short-form-36 (p = 0.176 mental, p = 0.756 physical), Western Ontario and McMaster Universities Osteoarthritis Index (p = 0.847), pain scores (p = 0.458) or complications. The mean rate of linear wear was 0.028 mm/year (standard deviation (sd) 0.010) for Group A, 0.023 mm/year (sd 0.010) for Group B, and 0.09 mm/year (sd 0.045) for Group C. Penetration was significantly higher in the UHMWPE liner group compared with both XLPE liner groups (p < 0.001) but no significant difference was noted between CoCr and OxZi when articulating with XLPE (p = 0.153). In this, the largest randomised study of this bearing surface, it appears that using a XLPE acetabular liner is more important in reducing THA component wear than the choice of femoral head bearing, at mid-term follow-up. There is a non-significant trend towards lower wear, coupling OxZi rather than CoCr with XLPE but long-term analysis is required to see if this observation changes with time and becomes significant.

Cite this article: Bone Joint J 2015;97-B:883–9.

The study aim was to simulate oblique spinous process abutment (SPA) in cadaveric spines and determine how this affects coupled motion in the coronal plane.

L4-S1 spinal segments from thirteen cadavers were loaded on a materials testing machine in pure compression at 1kN for 10 minutes. Reflective markers on the vertebral bodies were used to assess coronal motion using a motion analysis system. Oblique SPA was simulated by attaching moulded oblique aluminium strips to the L4 and L5 spinous processes. In each specimen, both a right- and left-sided SPA was simulated, in random order, and compression at 1kN was again applied. All tests were then repeated after endplate fracture. Coronal plane motion at baseline was compared with values following simulated SPA using Mann Whitney U-tests.

Pre-fracture, SPA increased coronal motion by 0.28° and 0.34° on right and left sides respectively, compared to baseline, only the former was significant (P=0.03). Post-fracture, SPA decreased coronal motion by 0.36° and 0.46° on right and left sides respectively, only the latter was significant (P=0.03). Simulated oblique SPA in the intact spine initiated an increase in coronal motion during pure axial loading. These findings provide limited evidence that oblique SPA may be causative in DLS.

An often neglected component of sagittal balance in adolescent idiopathic scoliosis (AIS) is the cervical spine. The cervical spine is capable of compensating for large sagittal deformities by altering head position, but in doing so may give rise to symptoms when the extremes of cervical compensatory mechanisms are reached. This paper seeks to define whether AIS patients have a different cervical lordosis pre and post corrective surgery when compared to normal adolescents.

A review of the literature was carried out in order to define normal cervical lordosis in adolescents. A retrospective analysis of 81 patients with a confirmed diagnosis of idiopathic scoliosis who had received corrective surgery was carried out, and pre and post op cervical lordosis of C1– C7 and C2– C7 were independently measured and recorded using full length sagittal spine radiographs. This data was compared to the 95% confidence interval (95% CI) of cervical lordosis in controls to show if AIS patients showed different cervical spine lordosis before or after corrective surgery.

A literature search showed that normal cervical spine lordosis values are poorly described. However, some values have been published. One study (paper A) gives values of −16° (95%CI −12–20°) for male C2– C7 lordosis and −15° (95% CI −12.5–17.5°) for female C2– C7 adolescents. Another reference (paper B) gives values of −8.4 (95%CI −6.7–10.1°) for male and −1.9 (95%CI −0.5–3.3°) for female adolescents for the same C2– C7 measurements. Our values for male patients for pre op C2– C7 lordosis was −1.2 (95%CI −8.5–6.1°) and 9° (95%CI 2.9– 15.1°) for females. Post op values were 10.6° (95%CI 2.4–18.8°) for males and 8.3° (95%CI 4.8–11.8°) for females.

The values of cervical lordosis in our series show that patients with AIS have a significantly different cervical lordosis when compared to normal values both pre and post deformity correction (p < 0.05). A complete understanding of how the cervical spine is positioned prior to surgery is critical, as flattening the thoracic spine during corrective surgery could give rise to cervical pain and sagittal imbalance if the ability of the cervical spine to compensate for the new spinal position is exceeded.

AIS is present in 3–5% of the general population. Large curves are associated with increased pain and reduced quality of life. However, no information is available on the impact of smaller curves, many of which do not reach secondary care. The objective of this project was to identify whether or not there is any hidden burden of disease associated with smaller spinal curves.

The Avon Longitudinal Study of Parents and Children (ALSPAC) is a population-based birth cohort that recruited over 14,000 pregnant women from the Bristol area between 1991–1992 and has followed up their offspring regularly. At aged 15 presence or absence of spinal curvature ≥6degrees was identified using the validated DXA Scoliosis Measure in 5299 participants. At aged 18 a structured pain questionnaire was administered to 4083 participants. Chi-squared was used to investigate any association between presence of a spinal curve at aged 15 and self-reported pain at aged 18 years. Sensitivity analyses were performed by rerunning analyses after excluding those who were told at aged 13 they had a spinal curve (n=27), and using a higher spinal curve cut-off of ≥10degrees.

Full data was available for 3184 participants. Of these, 56.8% were female, and 4.2% non-white reflecting the local population. 202 (6.3%) had a spinal curve ≥6degrees and 125 (3.9%) had a curve ≥10degrees. The mean curve size was 12degrees. 140/202 (69.3%) had single curves, and 57.4% of these were to the right. In total 46.3% of the 3184 participants reported aches and pains that lasted for a day or longer in the previous month, consistent with previous literature. 16.3% reported back pain. Those with spinal curves ≥6degrees were 42% more likely to report back pain than those without (OR 1.42, 95%CI 1.00 to 2.02, P=0.047). In addition, those with spinal curves had more days off school, were more likely to avoid activities that caused their pain, were more likely to think that something harmful is happening when they get the pain, and were more afraid of the pain than people without spinal curves (P<0.05). Sensitivity analyses did not change results.

We present the first results from a population-based study of the impact of small spinal curves and identify an important hidden burden of disease. Our results highlight that small scoliotic curves that may not present to secondary care are nonetheless associated with increased pain, more days off school and avoidance of activities.

The prevalence of degenerative spondylolisthesis (DS) increases with age. With an ageing population there will be increasing demands for adult deformity surgery, with associated significant financial and complication costs. The prevalence of lytic spondylolisthesis (LS) is 6–8%. Our clinical observation is that it is extremely rare to see LS in the presence of DS and therefore the objective was to formally describe the prevalence of LS in combination with DS to assess the hypothesis that 6–8% of patients with DS should also have LS. If this is not the case it may further our understanding of the pathogenesis of DS, which could aid in future prevention or treatment.

A retrospective review of erect lateral lumbar radiographs demonstrating lumbar spondylolisthesis was performed. Radiographs were identified and analysed on the hospital Synapse Picture Archiving and Communication System (PACS). Search criteria were radiographs requested by primary care and patients aged over 60.

101 patients with spondylolisthesis were identified. 89% were requested for back or leg pain. There were 89 patients with DS (69.7% women) and 12 with LS (83% men). The average age of DS and LS patient was 75 and 70 respectively (not significant). There were no cases found with both DS and LS. This was significantly different to the expected amount of 6% (p=0.03). The level of DS was at L3/4 in 11.2% (n=10), L4/5 in 79.8% (n=71) and L5/S1 in 16.9% (n=15). 2 levels were involved in 7 patients. 94.4% (n=84) demonstrated a Meyerding grade 1 slip and 5.6% (n=5) grade 2 slip. For LS the slipped level was at L5/S1 in all cases. 66.7% (n=8) had a grade 1 slip and 33.3% (n=4) a grade 2 slip.

We found no cases of lytic spondylolisthesis in the presence of degenerative spondylolisthesis. We hypothesis that the presence of spondylolysis or lytic spondylolisthesis may be protective against development of degenerative spondylolisthesis. More work is needed to explore this further.

Aim:

The Lenke Classification for adolescent idiopathic scoliosis (AIS) classifies curves as nonstructural if they reduce to less than 25° on bending radiographs. We aimed to establish whether there is a significant difference in curves assessed as structural/ nonstructural when comparing bending radiographs to forced traction radiographs.

Aim:

To compare the degree of deformity correction achieved using cobalt chromium versus titanium alloy rods in patients with Adolescent Idiopathic Scoliosis.

Aim:

Deep infection following paediatric spinal deformity surgery is a serious complication, which can also result in increased length of stay and significant cost implications. Our objective was to reduce deep infection rates following spinal deformity surgery.

Aim:

To determine if patients with coronal plane deformity in the lumbar spine have a higher grade of lumbar spine subtype compared to controls.

Aim:

To compare the ability of fulcrum bend and traction radiographs to predict correction of AIS using pedicle screw only constructs and to compare the fulcrum bending correction index (FBCI) with a new measurement: the traction correction index (TCI).

Aim:

Recent guidelines have been published by the Association of Neurophysiological Scientists / British Society for Clinical Neurophysiology (ANS/BSCN) regarding the use of intra-operative neurophysiological monitoring (IOM) during spinal deformity procedures. We present our unit's experience with IOM and the compliance with national guidelines.

Introduction

In Total Hip Arthroplasty (THA), polyethylene wear reduction is key to implant longevity. Oxidized Zirconium (OxZi) unites properties of a ceramic bearing surface and metal head, producing less wear in comparison to standard Cobalt-Chromium (CoCr) when articulating with Cross-linked polyethylene (XLPE) in vitro. This study investigates in vivo polyethylene (PE) wear, outcomes and complications for these two bearing couples in patients at 5 year follow-up

Objective

Pyogenic spinal infection (PSI) is an increasingly common presentation to spinal units in the UK. Its investigation and diagnosis is often delayed. The purpose of this study was to determine the prognostic significance of the inflammatory marker levels on admission on achieving a positive microbiological diagnosis in patients with PSI.

Objective

The purpose of this study is to describe and validate a CT based classification of lumbosacral segment abnormalities.

Purpose

To highlight the cardiovascular responses of a trainee and supervising consultant while performing Total Knee Arthroplasty (TKA) and to demonstrate the impact that supervision has on both their responses.

Computer assisted surgery is becoming more prevalent in spinal surgery with most published literature suggesting an improvement in accuracy and reduction in radiation exposure. This has been particularly highlighted in scoliosis surgery with regard to the placement of pedicle screws. Anecdotally this has been challenged with concerns with regard to the steep learning curve using this equipment and the high cost of purchasing said systems. The more traditional technique utilises the surgeon's knowledge of anatomic landmarks and tactile palpation added with fluoroscopy to place pedicle screws. We retrospectively looked at 161 scoliosis corrections performed using this technique over three years by 3 main surgeons at the same centre (Frenchay). With an average of 10 levels per procedure and over 2000 pedicle screws inserted. We reviewed the radiation time exposure and dose of radiation given during each case. Our results compared favourably to published data using computer and robot assisted surgery with an average exposure time of 80 seconds and a mean dose of 144 mGy using a standard C-arm guided fluoroscopy. Our study suggests that armed with good surgical knowledge and technique it is possible to obtained low levels of radiation exposure of benefit to both patient and the operating team.