Total knee arthroplasty (TKA) disturbs patellar blood flow, an unintended accompaniment to TKA that may be a cause for postoperative anterior knee pain. We compared patellar blood flow before and after medial parapatellar arthrotomy to pre- and postoperative anterior knee pain scores to ascertain whether disrupted patellar blood flow correlates with anterior knee pain following TKA. Blood flow measurements were performed at full extension and at 30°, 60°, 90° and 110° of flexion prior to and after medial arthrotomy in 50 patients (21 male, 29 female; mean age 73.1±8.6 years) undergoing TKA. Anterior knee pain was assessed using the pain intensity numeric rating scale. A significant decrease in blood flow was detected at 60°, 90°, and 110° of flexion (p values: 0.00314,< 0.0001,< 0.0001 respectively). The medial arthrotomy did not have a statistically significant influence on patellar blood flow in the Students’ t-test (margin of significance p& #61603;0.05) Nineteen patients exhibited an average 14% (range 1%–54%) increase in patellar blood perfusion at knee flexions of 90° and 110° after medial arthrotomy (p value: 0.32) Prior to TKA, 16 of the 50 patients (32%) complained of anterior knee pain (average NRS 7.12, range 5–10). At 6-month follow up, 4 of the 16 patients (25%) complained of moderate anterior pain (average NRS 5.7, range 5–6), while 8 of 16 (50%) patients reported discomfort (average NRS 3.5, range 2–4) around the patella. No statistically significant correlation was found between intraoperative findings on patellar blood flow and the presence of anterior knee pain

Background: context: Length of hospital stay (LOS) varies widely within patients with posterior spinal fusion. So far there is little evidence on its co-variates.

Purpose: This study examined which co-variates influence LOS in posterior spinal fusion. Study design: Prospective consecutive documentation of hospital based interventions in the international spine registry Spine Tango. Patient sample: Between 05/2005 and 11/2006 data of 3437 patients were documented in the registry. 790 patients with degenerative spinal disease (614) or spondylolisthesis (176), who had been treated with posterior decompression and spinal fusion, were included in this study. Median age was 62.8 yrs (min 13.2 yrs, max 89.8 yrs) with a female to male ratio of 2:1. Median LOS was 11 days (IQR 8–14 d). Outcome measures: LOS was chosen as dependent outcome variable.

Methods: Multiple linear regression was performed on following independent variables: age, gender, main pathology, number of spinal segments of posterior fusion, level of fusion, number of previous spinal surgeries, operation time, clinic (number of fusions, academic status), surgeon credentials, type of fusion (sole fusion, fusion + instrumentation, fusion + instrumentation + cage).

Results: Clinic (p< 0.0001) was found to be a highly significant co-variate for LOS (min 7 d, max 14 d). Number of fusions per clinic (min 25, max 434) and academic status of clinic had no influence on LOS. Further significant covariates were surgeon credentials (surgeons in training: 8.5 d, specialised spine surgeons: 11 d, orthopaedic or neurosurgeons: 12 d; p=0.001), number of spinal segments of posterior fusion (1 segment: 10 d, 2–3 segments: 12 d, 4–5 segments: 12.5 d, > 5 segments: 15 d; p=0.002), and age group (< 50 yrs: 9 d, 50–59 yrs: 11 d, 60–69 yrs: 12 d, ≥70 yrs: 13 d; p=0.01). Borderline significance was found for gender (women: 12 d, men: 10 d; p=0.05). All other variables showed no influence on LOS.

Conclusion: Co-variates of LOS of patients with posterior spinal fusion are clinic, independent of number of spinal surgeries per clinic and academic status of clinic, surgeon credentials, number of segments of fusion, age group, and gender. A short LOS in surgeries performed by surgeons in training is explained by a smaller number of segments of fusions in these procedures. A subgroup analysis on the co-variate clinic should be performed assessing further explanatory variables. However, this goes beyond the possibilities of documentation in a spine registry.

As an example of benchmarking in spinal surgery using Spine Tango, we extracted data on dural tears, one of the most frequent types of complications in posterior spinal fusion. Little is known about their predictors. This study examined which factors predict the occurrence of dural tears in posterior spinal fusion.

Prospective consecutive documentation of hospital based interventions with an evidence level 2++. Between May 2005 and November 2006 data of 3437 patients were documented in the registry. Nine hundred and twenty nine patients, who had been treated with posterior spinal fusion after opening of the spinal canal, were included in this study. Dural tears being the most frequent type of complications in the registry were chosen as dependent outcome variable. Multiple linear regression with stepwise elimination was performed on potential predictor-variables of the occurrence of dural tears. Benchmarking compared the performance of single hospitals with international peers. Median age was 62.7 years (min 12.5, max 90.5 yrs) with a female to male ratio of 2:1. In 18 of 929 cases a dural tear occurred. Hospital (p=0.02) and number of segments of fusion (p=0.018) were found to be predictors of the occurrence of dural tears in posterior spinal fusion. Number of fusions per hospital (min 25, max 526) and academic status of hospital had no influence on the rate of dural tears. Fusions of four and more segments showed an increase of the rate of dural tears by a factor of three compared to fusions of less than four segments. There was no significant difference between fusions of one segment and fusions of two or three segments (1.3 vs. 1.9%) as well as between fusions of four or five segments and fusions of more than five segments (4.6 vs. 4.2%). Differences between hospitals remained when benchmarking dural tears with case mix.

Predictors of dural tears in posterior spinal fusion are

hospital and

In fusions of four and more segments a threefold higher risk of dural tears in comparison to fusions of less than four segments should be taken into consideration.

Introduction: With a life of over five years, Spine Tango can be considered the first truly International Spine Registry. The Swedish Spine Registry has already shown the feasibility of a registry on a national level. But, there is a need for an international spine registry allowing a benchmarking on an international level. Here we demonstrate the genesis of questionnaire development, the constantly increasing activity, and limitations of the International Spine Registry Spine Tango.

Methods: From 2002 until 2007 about 9000 datasets were submitted by 28 hospitals in nine countries worldwide. Three different generations of Spine Tango questionnaires were used for documentation.

Results: To cope with varying international administrative issues and legal requirements of data anonymisation, national Spine Tango modules are necessary. Four national Spine Tango modules are in operation to date, another three modules are in the process of roll-out. Considering all these participants, Spine Tango will soon expand to include data from 52 hospitals in 18 countries. One-fourth of these hospitals are University Hospitals, which are destined to take the lead in the Spine Tango registry as opinion leading hospitals. Although the number of participants is steadily growing, no country is yet represented with a sufficient number of hospitals. Indisputably, a marketing concept is needed. An acquisition of new centres via national spine societies seems an obvious strategic approach. Further limitations of Spine Tango include the low number and short duration of follow-ups and the lack of sufficiently detailed patient based data on subgroup level.

Discussion: Spine Tango has achieved a firm position as international spine registry and with its increasing acceptance it is also gaining importance. The strengths of Spine Tango include a potentially very large network, the participation of a specialized international society and an academic partner with expertise and extensive experience in registry implementation. Data analysis from Spine Tango is possible but complicated by the incompatibility of generations one and two with the more recent generation three. Consequently findings cannot yet be generalized to any specific country or patient population. Nevertheless, the potential benefits of the project for the whole spine community become increasingly visible. In the near future, the established Spine Tango version three with standardised patient based data will make outcome evaluations possible. In parallel to the International Spine Registry Spine Tango, a National Spine Registry in Australia could be set up – comparable to AOA’s National Joint Replacement Registry.

Introduction: As an example of possibilities of Spine Tango we extracted data on dural tears, one of the most frequent types of complications in posterior spinal fusion. Little is known about their predictors. This study examined which factors predict the occurrence of dural tears in posterior spinal fusion.

Methods: Prospective consecutive documentation of hospital based interventions with an evidence level 2++. Between 05/2005 and 11/2006 data of 3437 patients were documented in the registry. 929 patients, who had been treated with posterior spinal fusion after opening of the spinal canal, were included in this study. Median age was 62.7 yrs (min 12.5, max 90.5 yrs) with a female to male ratio of 2:1. In 18 of 929 cases a dural tear occurred. Dural tears being the most frequent type of complications in the registry were chosen as dependent outcome variable (3–6). Multiple linear regression with stepwise elimination was performed on potential predictor-variables of the occurrence of dural tears. Benchmarking compared the performance of single hospitals with international peers.

Results: Hospital (p=0.02) and number of segments of fusion (p=0.018) were found to be predictors of the occurrence of dural tears in posterior spinal fusion. Number of fusions per hospital (min 25, max 526) and academic status of hospital had no influence on the rate of dural tears. Fusions of four and more segments showed an increase of the rate of dural tears by a factor of three compared to fusions of less than four segments. There was no significant difference between fusions of one segment and fusions of two or three segments (1.3 vs. 1.9%) as well as between fusions of four or five segments and fusions of more than five segments (4.6 vs. 4.2%). Differences between hospitals remained when benchmarking dural lesions with case mix.

Discussion: The feasibility of data analysis and benchmarking from the International Spine Registry Spine Tango could be demonstrated. Predictors of dural tears in posterior spinal fusion are

hospital and

In fusions of four and more segments a threefold higher risk of dural tears in comparison to fusions of less than four segments should be taken into consideration. A subgroup analysis on the predictor-variable hospital should be performed assessing further covariates. However, this goes beyond the possibilities of documentation in this international spine registry.

Introduction: Lumbar spinal stenosis is a frequent indication for spinal surgery. The predictive quality of treadmill testing and MRI for diagnostic verification is not yet clearly defined. The aim of our study was to assess correlations between treadmill testing and MRI findings in the lumbar spine.

Methods: Patients with lumbar spinal stenosis who had been admitted for surgical treatment by means of decompression with or without stabilisation were prospectively examined. We included patients with lumbar spinal stenosis as defined by clinical symptoms like low back and/or leg pain, which increased when walking, and by the area of the dural sac examined by MRI. We excluded patients with clinically manifest peripheral arterial disease, polyneuropathy or musculoskeletal impairments compromising the ability to walk. Treadmill tests were performed using the standardized testing protocoll by Deen at a speed of 0.5 m/sec without inclination. After the onset of symptoms (pain, weakness or dysaesthesia), each patient decided when to end the test.

The area of the dural sac and neuroforamina was examined with MRI for the narrowest spinal segment. ODI and VAS were used for clinical assessment.

Results: 25 patients were included with a median age of 67 years (Interquartile range IQR 60–72 yrs). In the narrowest spinal segment the median area of the dural sac was 91mm2 (IQR 67–135 mm2). The median ODI was 66 percent (IQR 64–72 percent). The median walking distance in the treadmill test was 70 m (IQR 30–130 m). The distance reached in the treadmill test correlated with the area of the dural sac (Spearman’s rho=0.53) and ODI (rho=0.51), but not with the area of the neuroforamina and VAS.

Discussion: The treadmill test helps objectifying pre- and postsurgical clinical complaints and verifying a lumbar spinal stenosis by creating a situation of dynamic strain. Moreover, the treadmill test lets the patient experience his own physical limits and enables the examiner to attain a replicable postoperative assessment. The distance reached in the treadmill test predicts the grade of stenosis in MRI but has a limited diagnostic importance for the level of clinical symptoms in lumbar spinal stenosis.

SPINE TANGO is the first International Spine Register. While it has now been fully operational for five years, no results of its collected data have been presented yet. The Swedish Spine Register has already shown that a National Spine Register can generate valid and meaningful data. Here we present data from the first three versions of SPINE TANGO.

From 2002 until 2006 about 6000 datasets were submitted by 25 hospitals worldwide. Descriptive analysis was performed for demographic, surgery, and follow-up data comparing all three versions of SPINE TANGO.

Over the course of its existence the SPINE TANGO data base showed a rise in median patient age from 52.3 years to 58.6 years and an increasing percentage of degenerative disease as main pathology from 60.1% to 71.4 %. Posterior decompression was the most frequent surgical measure. About one third of all patients had follow-ups. Rehabilitation was arranged more frequently, especially home-based and outpatient rehabilitation. The complication rate was decreasing below 10%.

The feasibility of data analysis from the International Spine Register SPINE TANGO could be demonstrated performing descriptive analysis with an evidence level III. In the near future, the meanwhile established SPINE TANGO version 3 with patient based data will make outcome

evaluation possible. This will enable us to present more comprehensive analyses of SPINE TANGO and to make the data base even more beneficial for the whole spine community. In parallel to the International Spine Register SPINE TANGO, a National Spine Register in New Zealand could be set up – comparable to NZOA’s National Joint Register.

Introduction: Lumbar fusion is one of the most frequently recommended treatments in spinal surgery, whereas ALIF and PLF are discussed controversially. This prospective and consecutive study examined if complications and rehabilitation differed between patients with a degenerated lumbar spine, who had been treated with ALIF or PLF.

Methods: Between 04/2002 and 12/2005 clinical data of 39 patients, who were treated with ALIF, and of 296 patients, who received PLF, were submitted to the European Spine Register SSE Spine Tango. Complications and rehabilitation process were documented after a median follow-up time of 9 weeks (IQR 8–24 weeks). Analysis was performed with non-parametric tests. The study corresponds with an EBM-level 3.

Results: The median age of patients with ALIF was 56 years (IQR 37-66 yrs) vs. 64 yrs in the PLF group (IQR 54–72 yrs) with a male to female ratio 10:29 vs. 108:188.

Patients after ALIF and PLF had an even complication rate (5/39 vs. 26/296, p = 0,41). The types of complications in the ALIF group were less severe (sensory and motoric disturbance vs. implant failure and implant malposition). All five patients needing reintervention belonged to the PLF group. Three quarters of all patients underwent rehabilitation. The proportion of patients with outpatient rehabilitation was higher in the ALIF group (14/39 vs. 50/296 patients, p = 0,05).

Conclusions: Patients with degenerative lumbar spine disease have a less severe type of complications after ALIF than after PLF, whereas the complication rate is even. Concerning the higher proportion of patients with outpatient rehabilitation in the ALIF group, one has to consider their lower age compared with patients in the PLF group. Except for the severeness of complications and the proportion of outpatient rehabilitation one cannot conclude an advantage of either of the two surgical methods.

We assessed differences in the incidence and appearance of the radiological signs of loosening of the cup for various types of design. This was an observational study based on hip registry data of 15 340 patients with 17 951 total hip arthroplasties collected over a period of 33 years in 49 hospitals in Central Europe.

The threaded and the press-fit titanium cups showed significantly less aseptic loosening than the other systems. The direction of migration and the frequency of the radiological signs of loosening differed between the cup systems and were time-dependent.

Our findings indicate the superiority of uncemented threaded cups and press-fit titanium cups over other designs of cup.