Purpose: Recent studies have examined the systemic inflammation that occurs following spinal cord injury (SCI) (Gris et al. 2008). It is believed that this systemic inflammation plays a role in the respiratory, renal and hepatic morbidity of SCI patients, ultimately contributing to mortality post-injury. Evidence of this inflammatory response has been shown as early as two hours post SCI (Gris et al. 2008) Intravital microscopy is a powerful tool for assessing inflammation acutely and in ‘real-time’ (Brock et al. 1999). This tool would be useful for demonstrating the acuteness of a systemic inflammatory response post-SCI, and for assessing the degree of inflammation to different severities of SCI. The liver has been shown to play a particularly important role in the initiation and progression of the early systemic inflammatory response to spinal cord injury (SCI), therefore the purpose was to evaluate hepatic inflammation immediately after SCI. We hypothesized that SCI would cause immediate leukocyte recruitment and that the magnitude of inflammation would increase with increasing severity of cord injury.

Method: Male Wistar rats (200–225g) were randomly assigned to one of the following groups: uninjured, trauma-injured (laminectomy and no cord injury), cord compressed or cord transected. Spinal cord-injured rats were anesthetized by isoflurane, a dorsal laminectomy was performed, and the 4th thoracic spinal segment was injured by a moderately severe clip-compression injury or by a severe complete cord transection injury. Uninjured rats and trauma-injured rats served as controls. At 0.5 and 1.5 h after SCI rats had the left lobe of their livers externalized and visualized using intravital video microscopy.

Results: At 0.5 hours the total number of leukocytes per post-sinusoidal venule was significantly increased after cord compression and cord transection compared to that in uninjured and trauma-injured rats (P< 0.05). Of these leukocytes significantly more were either adherent or rolling along venule walls compared to uninjured and trauma-injured rats (P< 0.05). Of the rolling leukocytes 2–fold more were observed after cord transection compared to cord compression. At 1.5 h the total number of leukocytes per post-sinusoidal venule and the number of adherent leukocytes was significantly increased only after cord transection.

Conclusion: Injury to the spinal cord but not trauma alone causes immediate leukocyte recruitment to the liver within 0.5 h after injury. Also, leukocyte recruitment increases with increasing severity of injury. This is the first study to use intravital microscopy to visualize systemic inflammation in the liver following SCI.

Purpose: To report the clinical and radiographic prospective results of a consecutive series of patient with a minimum two year follow-up with the Charite Total Disc Arthroplasty (TDA).

Method: Between 2001 and 2005, sixty patients underwent a Charite TDA (Depuy Spine, Raynham, MA) at either L4-5 or L5-S1. The primary indication for surgery was discogenic low back pain confirmed by provocative discography. Clinical assessment was carried out preoperatively and postoperatively at 3, 6, 12 months, and once a year thereafter using the Oswestry Disability Index (ODI), Visual Analogue Scale (VAS) for back and leg pain, and SF-36. Radiographic analysis included: angle of sagittal rotation, translation of the rostral vertebra onto the caudal vertebra, anterior vertical motion (AVM), middle vertical motion (MVM), posterior vertical motion (PVM), pre- and post-operative lumbar lordosis, disc height and subsidence of the TDA. The radiographic measurements were performed using the GE Medical Systems Centricity PACS Software Version 1.0.

Results: There were 36 female and 24 male patients with a mean age of 39 (range 21–59). The mean duration of low back pain was 70 months. Twenty-five percent claimed work compensation status. The mean postoperative hospital stay was 4.8 days. A statistical significant improvement was demonstrated between the mean pre-operative ODI (50) and all post-operative intervals (p< 0.0001) which had declined to 27.7 by one year. Similarly, pre-operative VAS back pain (8.0), leg pain (6.1), SF-36 physical component summary score (33.5) and mental component summary score (41.8) remained improved (p< 0.0001) by three months (4.1, 3.1, 51.7, 62.0 respectively). One patient with an L5-S1 TDA has since undergone a posterolateral instrumented fusion. The mean pre- and post-operative lumbar lordosis was 34.58 and 53.48 respectively. The mean saggital rotation was 6.5 degrees at 5 year follow-up, while the mean translation was 0.83 mm. The mean AVM, MVM and PVM were 0.59 mm, −3.96 mm and 3.69 mm respectively at 5 year follow-up.

Conclusion: This study demonstrates satisfactory clinical results in carefully selected patients. The radiographic assessment confirmed preservation of movement at the replaced disc during flexion and extension of the lumbar spine.

Purpose: To investigate subsidence of the Charite total disc arthroplasty (TDA) and to identify if a discrepancy between vertebral endplate and the Charite footprint predispose to subsidence.

Methods: Between July 2001 and May 2008 64 patients underwent a Charite TDA (DePuy Spine, Raynham, MA). They were prospectively followed at 3, 6, 12 months, and once a year thereafter.

The following measurements were performed on the replaced motion segment using a lateral radiograph:

The anterior-posterior (AP) dimension of the end plates.

The ratio between the actual and radiographic AP length of the metal endplate was calculated and utilized as the correction factor for the error of magnification on all other radiographic measurements.

Results: At L5-S1 the mean subsidence was 1.87 mm and occurred exclusively at the posterior part of the inferior end plate of L5. The mean posterior uncoverage was 3.5 mm (L5) and 0.27 mm (S1).

At L4–L5 the mean subsidence was 1.48 mm (L4) and 0.56 mm (L5). Posterior uncoverage of L4 and L5 vertebrae were 4.81 and 2.22 mm, respectively.

Subsidence of more than 1 mm was present in all cases where the posterior uncoverage of the end plate with the TDA was more than 2 mm (odds ratio: 5.7). Subsidence was non – progressive in all cases.

An anatomic mismatch exists between L5 and S1 endplates in the AP dimension; in more than half the patients S1 is shorter than L5.

Conclusion: The radiographic measurements suggest an increased likelihood of subsidence with more than 2 mm of posterior uncoverage of the end plate by the TDA. The endplate AP length of S1 is frequently less than that of L5. Implant selection based on the smaller S1 endplate may produce worrisome uncoverage of the L5 inferior endplate leading to an increased risk of subsidence and possible catastrophic failure. TDA design should afford modularity to compensate.

No financial benefits or funding has been received for the completion of this study.

Hip arthroplasty has its true genesis in 1962 when the Charnley Total Hip was first implanted. The system comprised a stainless steel femoral stem with fixed 22,225mm head articulating against an all polyethylene acetabular cup. Both components were fixed in position with acrylic bone cement. There have been a number of changes in design, materials and surgical technique but the essential concept remains the same. The system was widely used by both senior and junior surgeons. Numerically implantations peaked at ~45,000 per annum in the late1980’s and is still at around ~25,000 per annum in the mid 2000’s. Geographically the system was used in all five continents. Patients varied widely both in age, activity, and diagnosis. It would therefore seem an appropriate vehicle to examine the variations in results of total hip replacement by patient profile, geography, and era of implantation.

A search was carried out on the US NCBI website for publications reporting on results with the Charnley system up to the end of 2002, and which comprised a follow-up of more than 10 years, and gave survivorship data. This resulted in 28 papers with 14 countries of origin available for review. For all studies basic data such as age and diagnosis, range implantation dates, likely specific design of prosthesis, origin of study and number in study was either reported or could be deduced. A ten year survivorship was reported in 16 studies for stem and cup and 7 for stem only. If the longest follow-up was considered for each study then 18 reported on stem and cup (9392 hips, implanted 1962–92) and 15 on stem only (4243 hips, implanted 1966–91). A total of 11 studies had four of more points on a survivorship curve, seven with stem and cup, four with stem only.

There are a number of points of interest in this data. The first is that with one exception the performance is remarkably consistent as shown by the survivorship curves. There is no significant difference in the survival rates from different centres, countries, and with implantation dates ranging from 1962 through to 1992. Secondly, there appears to have been little or no change in the average age of patients with implant date. There is some evidence to indicate from the 10 year data that failure rate per year is lower in older patients but does not seem to be affected by implantation date. The latter despite the fact that both surgical technique and component design changed over the 30 year implantation period. A further observation is that the failure rate per year is lower in studies with greater numbers of patients.

The general conclusion from this review is that the Charnley Total Hip is remarkably consistent in its performance both over time and location of implantation. Its performance also seems to have been affected very little by changes in technique or design.

This prospective study evaluates the outcome of a new metal -on-metal total hip replacement in a younger group of patients.

Fifty-five primary all-metal total hip replacements (THR) were evaluated prospectively at a follow-up of 2.8–5.5 years. Patients were selected according to age and activity levels. The mean age was 58 years (41–69). 33 males and 22 females were included in the study. Surgery was carried out for osteoarthritis in 52 patients and for non-union fractured femoral neck, ankylosing spondilitis and post slipped upper femoral epiphysis in the three remaining patients. A single surgeon (the senior author) through the posterior approach carried out the surgery. All patients received the porous coated titanium shell with a Morse taper cobalt chrome liner and double wedge tapered polished cobalt chrome stem and modular head. Blood metal ion analysis was performed on a cohort of 24 patients using High Resolution Inductively Coupled Plasma Mass Spectrometry, sampling taken preoperatively and then repeated post operatively at 6 months, 1 year and then annually.

Clinical results have been excellent. X rays show Harris A cementation in all femurs, with no component migration or radiolucencies being identified on follow-up radiographs. No prosthesis to-date has required revision. One patient has died and one is lost to follow up. The following non-device related complications were reported in the group, 2 (4%) superficial wound infections, 1 (2%) dislocation, 1 (2%) thrombosis, 1 (2%) IT band defect and 2 (4%) impingement. The dislocation was treated with a closed reduction. The impingement has resolved by one year in both patients. The results of the pre and postoperative blood metal ion analysis demonstrate some elevated levels, these levels being similar to those previously reported in the literature.

The hybrid all-metal THR may represent a valuable alternative in the younger, high demand patient.