Introduction

BAG-S53P4 has similar mechanical properties as cortical bone tissue and can be used as an additive to bone allografts. The aim of this study was to evaluate the effect of adding BAG-S53P4 to chemically treated allografts with controlled grain size distribution.

Study Design: A prospective study evaluated patients’, orthopaedists’ and not affected children of the same age ratings’ of preoperative and postoperative cosmesis in adolescents undergoing posterior spinal fusion for idiopathic scoliosis. The cosmetic result based on a questionnaire was compared to clinical and radiological parameters. There was no correlation between the SAQ and objective clinical and radiologic parameters at all, whereas clinical and radiological parameters showed good correlation. We recommend to standardly evaluate the cosmetic outcome as after scoliosis correction surgery.

Introduction: Improving cosmesis is an important goal in scoliosis surgery. Patients’ satisfaction with the cosmetic outcome is essential in their evaluation of the surgical result. However, only few efforts were made in the past to investigate the cosmetic outcome. We performed a a prospective study evaluated patients’, orthopaedists’ and not affected children of the same age ratings’ of preoperative and postoperative cosmesis in adolescents undergoing posterior spinal fusion for idiopathic scoliosis. The cosmetic result based on a standardized questionnaire (SAQ, spinal appearance questionnaire) was compared to clinical and radiological parameters.

Patient sample: Preoperative and postoperative photographs were taken from 32 patients (22 female, 10 male, average age 14.6 years) preoperatively and postoperatively in a standardized manner.

Materials: The photographs were assessed by use of a modified SAQ. In addition radiological measurements were performed like the cobb angles of the main curves in the coronal and sagittal plane, plumb line deviation, shoulder inequality and pelvic obliquity. The clinical investigation included the measurements of shoulder asymmetry, pelvic obliquity, rip and lumbar hump, plumb line deviation, breast asymmetry and the postoperative evaluation of the scar.

Results: The items general appearance, body shape, rib hump, and shoulder inequality of the SAQ improved most (p< 0.025). The patients judged the cosmetic result better than surgeons and healthy children (on average: 11 out 15 parameters of the SAQ improved) The surgeons came to the worst judgement (only 5 of 15 parameters improved). The interrater correlation of the surgeons was poor (ICC< 0.58). There was no correlation between the SAQ and objective clinical and radiologic parameters at all, whereas clinical and radiological parameters showed good correlation.

Conclusion: As shown in our results objective clinical and radiological parameters do not correlate with the evaluation of the cosmetic result. Therefore we recommend to establish the evaluation of the cosmetic outcome as standard investigation after scoliosis correction surgery.

Background: Implant fractures are complications that have a great impact on the patient’s quality of life after total hip arthroplasty. Nevertheless their occurrence is often considered as rare in clinical practice. We compared incidences of implant fractures in various datasets in order to calculate the risk of a fracture and assess the quality of these datasets for such evaluations.

Methods: In a structured literature analysis based on a standardised methodology the incidence of reoperations was evaluated comparing clinical studies published in Medline-listed journals and annual reports of National Arthroplasty Registers worldwide. Case reports and experimental studies were not considered.

Results: The majority of clinical studies are monocentre trials. The publications comprise a cumulative number of 72,571 stems with 234 stem fractures, 73,743 cups with 191 component fractures, and 16,381 ceramic heads with 44 fractures. A survey among the members of the American Association of Hip and Knee Surgeons covered 64,483 primary operations, hence including a similar number of primary cases as all monocentre studies together. This dataset involves 355 implant fractures.

By contrast, worldwide Register data refer to 733,000 primary operations, i.e. approximately 10 times as many as sample-based datasets.

In general, sample-based datasets present higher revision rates than register data. The deviations are high, with a maximum factor of 64 for hip stems. Whereas the AAHKS survey exhibits lower deviations than the monocentre trials, they are still too high for this data collection tool being considered as reliable and safe to provide valid data for general conclusions.

The incidence of implant fractures after total hip arthroplasty in pooled worldwide arthroplasty register datasets is 304 fractures per 100.000 implants. In other words, one out of 323 patients has to undergo revision surgery due to an implant fracture after THA in their lifetime.

Conclusion: For general assessments in the context of implant fractures, register data have the highest value. Clinical studies, which often focus on a particular implant, are of very limited value for global conclusions. Structured surveys produce more reliable data than clinical studies and are superior to monocentre trials. However, the AAHKS survey presents data that also show considerable differences to data from registers.

For the detection of rare, but severe complications like implant fractures sample-based studies achieve the goal of providing accurate figures only to a very limited extent, even if the samples are large. Here, too, comprehensive national arthroplasty registers are the most suitable tool to identify such incidents and calculate reliable figures.

Contrary to the prevalent opinion, implant fractures still are a relevant problem in arthroplasty.

Introduction: Clinical follow-up studies are sample based, in contrast to arthroplasty register data, which refer to the entire population treated. Aim of this study is to assess the differences in revision rate to quantify bias-factors in published literature.

Materials and Methods: A structured literature review of Medline-listed peer reviewed journals on examples has been performed concerning implants with sufficient material in both data sources available. Products with inferior outcome were subsumed in a subgroup.

Results: The number of cases presented in peer reviewed journals are relatively low in general and show a high variability.

The average revision rate in peer reviewed literature is significantly lower than in arthroplasty register data-sets.

Studies published by the inventor of an implant tend to show superior outcome compared to independent publications and Arthroplasty Register data. Factors of 4 to more than 10 have been found, which has a significant impact for the results of Metaanalyses.

When an implant is taken from the market or replaced by a successor there is a significant decrease in publications, which limits the detection of failure mechanisms such as PE wear or insufficient locking mechanisms.

The final statement made about the product under investigation seem to follow a certain mainstream.

Discussion and Conclusion: Arthroplasty Register datasets are superior to Metaanalyses of peer reviewed literature concerning revision rate and the detection of failure mechanisms. Combined reviews could reduce bias factors and thereby raise the quality of reports.

Background: Recently, the effects of radiculopathy and nerve root blocks on driving reaction time (DRT) have been presented in the literature. To our knowledge, the relation between lumbar spinal fusion and DRT has not been studied before, although important for driving safety. So, we conducted the current study to test the hypotheses that DRT in the context of lumbar fusion is 1) altered in pre-postoperative comparison, 2) influenced by pain, 3) influenced by the patient’s driving skill and 4) different to the DRT of healthy controls.

Methods: 21 consecutive patients (age 53.5 years, SD 10.8) receiving primary lumbar fusion were tested for their DRT 1 day preoperatively (pre-op), 1 week postoperatively at the day before discharge (post-op) and at 3 months (follow-up; FU). DRT was assessed with a custom made driving simulator. Additionally, also the level of back pain was determined by VAS for usual pain (VAS-U) and for pain during testing (VAS-T). We also collected the participants’ subjective driving frequency. We used normative DRT data from 31 healthy controls of similar age for comparison with the patients.

Results: Pre-op DRT was 685 msec (Md; IQR 246), post-op DRT increased to 728 msec (Md; IQR 264) and decreased again to 671 msec (Md; IQR 202) at FU (p=0.007). Post-hoc analyses (alpha=0.017) found significant differences between post-op and FU DRT (p=0.007). Moderate to high correlations (between 0.537 and 0.680) were found between VAS of back pain and DRT (p between 0.001 and 0.012). No correlations were found between driving frequency and DRT. Controls showed a DRT of 487 msec (Md; IQR 116) which was significantly different from DRT of the patients at all three test occasions (p< 0.001).

Conclusion: We found minor increase in DRT 1 week post-op followed by a definite and significant decrease at 3 months FU. We think it is safe – with respect to DRT - to resume driving 3 months after lumbar fusion. It is difficult to draw any conclusions about the period between discharge and 3 months. We also found moderate and high correlations between DRT and the level of back pain and assume that back pain is a relevant factor influencing DRT.

Background: The role of frontal plane tibiofemoral alignment in subjects with patellofemoral pain syndrome (PFPS) is controversial and rarely discussed in the literature. As well, little research has been done on the effects of the hamstrings muscles on PFPS. The aim of the current study was to determine whether, in individuals with PFPS, frontal plane tibiofemoral alignment or muscular activity of the index knee’s crossing muscles is altered during maximum eccentric leg press exercise.

Methods: This cross-sectional study involved 19 patients with PFPS and 19 control subjects who were matched according to gender, age, and physical activity. During eccentric leg press action, frontal plane tibiofemoral alignment was assessed with a motion analysis system based on skin markers. Simultaneously, surfaceelectro-myography was used to assess the activity levels of the relevant knee crossing muscles. To assess the activity under functional conditions, a leg press with a footplate having variable stability was used for barefoot testing.

Findings: The PFPS subjects did not have significantly different frontal plane leg alignment compared to controls. On electromyography (EMG), PFPS patients had significantly lower levels of hamstring activity during eccentric leg exercise. The differences between the 2 groups (%; absolute differences normalized EMG) ranged from 19.57% (semitendinosus; stable footplate; p = 0.017) to 20.04% (biceps femoris; unstable foot-plate; p = 0.019) and 32.03% (semitendinosus; unstable footplate; p = 0.002).

Interpretation: PFPS is not linked to altered frontal plane leg alignment during eccentric leg pressing. However, PFPS is associated with eccentric under-activation of the hamstrings, which may be a compensatory strategy that maintains patellofemoral joint pressure within bearable levels.

Background: Clinical scores are widely used to evaluate the outcome of total knee arthroplasty (TKA). However, a lack of uniformity, the use of different terminology, and the diversity of methods used to translate numerical data into clinical outcomes have been described as potential problems. Gait analysis is believed to provide more objective parameters and allow the ascertainment of functional performance after knee arthroplasty. The aim of the present study was to obtain information about the correlation between the outcome in terms of locomotion and the clinical knee score after TKA.

Methods: 29 consecutive patients waiting for total knee arthroplasty (TKA) were included in the study. The Hospital for Special Surgery Score (HSS), the Knee Society Score (KSS) and a gait analysis were conducted 1 day prior to surgery and 3 months postoperatively. The following kinematic and temporospatial gait parameters, whose relevance has been established in knee arthroplasty were analyzed: In the sagittal plane, the following variables were determined: maximum knee flexion stance, maximum knee flexion swing, minimum hip flexion (= maximum hip extension) and minimum ankle dorsiflexion (= maximum ankle plantarflexion). The maximum pelvic obliquity stance was determined for analysis in the frontal plane while stride length, double support and gait velocity were calculated for temporospatial analysis. Data from the KSS and HSS were analyzed for the subgroups named pain, knee (knee-specific parameter), function and total sum. Pearson’s correlation coefficients were calculated for the above mentioned gait parameters and for knee score subgroups pre–and postoperatively.

Results: Preoperatively, positive correlations of r > 0.5 (0.001 < p < 0.005) were ascertained for maximum knee flexion swing, maximum pelvic obliquity stance, gait velocity and stride length, and were mainly determined for the subscore of function and the total sum of KSS and HSS. A lower correlation (r = 0.388, p = 0.041) was determined for maximum knee flexion stance. Postoperatively, positive correlations of r > 0.5 (0.000 < p < 0.003) were determined for gait velocity, maximum pelvic obliquity stance and stride length, mainly for the subscore of function and the total sum of KSS and HSS. A negative correlation of r < −0.5 (0.001 < p < 0.009) between these score subgroups and double support was only ascertained postoperatively. No correlations were registered between pain subscores of KSS or HSS and any of the gait variables.

Interpretation: In the current study we established high correlations particularly between temporospatial parameters and functional and total scores of KSS and HSS pre-and postoperatively. It is concluded that the functional subscores of KSS and HSS are particularly suitable to assess the dynamic outcome of TKA.

Study Design/Objective: Prospective two-leg cohort study on anterior cervical fusion versus cervical arthroplasty with emphasis on clinical outcome measures.

Patients and Methods: Between August 2003 and May 2005 21 consecutive patients underwent anterior cervical fusion with or without anterior decompression with 26 levels fused. Between December 2004 and August 2006 24 patients had cervical arthroplasty with 30 levels replaced. The mean age at operation of the fusion group was 52 years and 5 months (46–69) and for the arthroplasty group 51 years and 2 months (42–62). To establish fusion the Cervios® cage (Synthes) with or without anterior plating was used. In the arthroplasty group the Prodisc C® disc prothesis (Synthes) was used. Contraindication for arthroplasty were osteoporosis, osteopathies, spinal canal stenosis, hypertrophic spondylarthrosis, spondylolisthesis, tumors and privious infection. Both groups were comparable with respect to age and gender, diagnosis, level distribution and preoperative clinical outcome measures (VAS for nack pain and arm pain, neck disability index and SF-36–sub-scores pain, function, vitality).

Results: Postoperatively all of the clinical outcome measures significantly improved in both groups. After three months postoperatively no significant further improvement was evident.

VAS neck pain: Fusion group/arthroplasty group: Preoperatively 6.2/5.9 n.s., 6 weeks 3.5/3.1 n.s., 12 weeks 2.1/1.9 n.s, 1 year 2/2.1 n.s.

In the fusion group we had 1 recurrent radiculopathy and 1 non union without the need of further intervention. In the arthroplasty group we faced 1 recurrent laryngeus recurrens nerve palsy and 3 spontaneus fusions within 1 year postoperatively, which might not be classified as complication.

Conclusion: Short term outcome after both procedures is excellent in terms of pain relief and function. 10% spontaneus fusion after disc replacement within the first year was evident. In our series we found better results after 3 months to 1 year postoperatively with respect to the neck disability index and SF-36 subscore pain within the arthroplasty group.