In recent years, the direct anterior approach (DAA) has become a standard approach for primary total hip arthroplasty (THA). With the increasing use of the DAA in primary cases also more and more revision surgeries are performed through the same interval. With ability to extend the DAA interval proximally and distally, loose cups, loose stems, and even periprosthetic femoral fractures (PPF) can be treated. Especially, PPF are devastating complications causing functional limitations and increased mortality. Therefore, we conducted a study to report the outcome of surgical treatment of PPF with the DAA interval.

We report on the one year complications and mortality in 40 cases with a mean clinical follow-up of 1.5 years. Mean age of patients was 74.3 years. Fractures were classified as Vancouver B2 (36), and B3 (N=4). In 14 cases, a standard stem was used, and in 26 cases a modular revision stem. In 30 cases, a distal extension +/- tensor release was used, in 4 cases a proximal tensor release was done, and in the remaining 6 cases revision could be performed without extension of the approach.

Median cut/suture time was 152 minutes (IQR 80 – 279). The overall complication rate in our patient group was 12.5%. 2 patients died in the first three months after operation. One patient had a transient femoral nerve palsy, which completely recovered.

The DAA interval to the hip for the treatment of PFF showed similar results compared with other approaches regarding mortality, complications, fracture healing, dislocation rate and clinical results. We conclude that femoral revision in case of PPF in the DAA interval is a safe and reliable procedure. Each Vancouver type of periprosthetic fracture can be treated by use of this approach.

In the last years custom-fit cutting guides using magnetic resonance imaging (MRI) were introduced by orthopedic surgeons for total knee arthroplasty (TKA). One of the advantages of these shape-fitting jigs is the possibility to transfer the preoperative planning of the TKA directly to the individual patient's bone. However, one has to be aware, that the jigs are designed for single-use and have to be custom made by an external manufacturer. This increases the cost of implantation and unlinks the surgeon from this process. In addition a potentially necessary adjustment of the preoperatively planned implant size and position in a surgical situation is not possible.

The purpose of our development was to combine the advantages of custom-fit cutting guides as a 3-D-computer-assisted planning tool with the option to adjust and improve the preoperative planning and the jig in the actual surgical situation. In addition no outside jig manufacturing would occur in this concept. This leaves the surgeon in control of the entire process.

The purpose of this study was to examine the reliability of this screw-based shape – fitting system. In order to do this we assessed the inter- and intra-observer reliability of the recurrent placement of the plate on a set of bone samples with preset screws.

We developed a plate with the dimension of 66 × 76 × 10 mm, containing 443 threaded holes. A connector for further instrumentation is mounted on the proximal part of the plate,. As the plate and the screws are made of aluminum and steel, sterilization is possible.

After computer tomography (CT) scans were taken from three human femoral bones, eight to nine variably positioned screws (50.45 mm length, 2.75 mm diameter), reversibly fixed by locknuts, formed an imprint of a bone's surface. For calculating precise screw positions, a computer-based planning software was developed resulting in a three-dimensional reconstruction of the bony surfaces. The plate was integrated in the 3-D reconstruction software. With a defined distance to the distal part of the femurs, allowed the proper length and position of the screws to be calculated. These calculations were transferred to the screws on the real plate.

In the next step the plate was positioned on the bony surface and after reaching the planned position the plate's connector was rigidly fixed to the bone. The plate was removed to give place to link saw jigs to the connector.

Planning and setting of the plate and the screws were conducted on three femoral bones.

Examinations were performed by five investigators with ten repetitions on each bone with three distinct plates. Intra- and inter-observer variability was assessed by measuring the variation in plate position between the trials.

The jigs were placed in a mean frontal tilting (medial to lateral) of 0.83°. The mean axial tilting (proximal to distal) was 1.66° and the mean shift on the axis from proximal to distal 8.48 mm. The shift and the tilting were significantly bone dependent but not user dependent. Compared with previous studies the deviation from the mechanical axis were comparable with conventional TKA (2.6° and 0.4°), computer assisted TKA (1.4° and 1.9°) and Custom-fit TKA (1.2°).

We developed a preoperative planning system for TKA that allows a transfer of the planning and the calculated imprint of the bones surface on a grid-plate during surgery by the surgeons themselves. Neither external manufacturers to create a fixed device nor a navigation system is necessary. Results showed the functioning of the screw – based shape fitting technique within the accuracy mentioned above. These findings are encouraging to do further research to examine the ideal number of screws to offer a perfect fitting.

Introduction

Austin Moore cervicocephalic prostheses have been a therapeutical option for femoral neck fractures in patients with a reduced general condition for many years. Since treatments other than total hip arthroplasties have also been included in National arthroplasty registers during the last decade, adequate reference data for comparative analyses have recently become available.

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.

Objective: The aim of this study was to show the effect of a universal (all neonates) ultrasound screening in newborns on the incidence of operative treatment of hip dysplasia.

Materials: A retrospective study was performed and all newborns of the county Tyrol (Austria) between 1978 and 1998 (8257 births / year ((range: 7766 – 8858)) were reviewed regarding hip dysplasia and following hip surgeries. Between 1978 and 1983 clinical examination alone was performed to detect hip dysplasia. Between 1983 and 1988 an ultrasound screening programme according to Graf was initiated in our county. Between 1988 and 1998 ultrasound screening was performed in all newborns. Hence two observation periods were determined: 1978–1983 and 1993–1998. The time period between 1983 and 1993 was excluded to minimize bias and learning curve regarding the initiation of the ultrasound screening programme. A retrospective comparative analysis of the two observation periods regarding surgical treatment and costs caused by hip dysplasia was performed. During the observation period indication for surgery did not change, however new treatment techniques were introduced. Patients with neuromuscular and Perthes diseases were excluded. According to age dependent surgical procedures three patient samples were determined: Group A: 0–1.5 years, Group B: 1.5–15 years and Group C: 15–35 years.

Results: Comparison of the two observation periods showed no influence on the number of interventions for dysplastic hips in group C (pelvic osteotomies and VDROs). In group A, a decrease of hip reductions was seen from 25.6±3.2 to 7.0± 1.4 cases per year. In group B, there was a decrease of operative procedures for dysplastic hips from 18.0±3.2 to 3.4±1.3 interventions per year. Since the introduction of universal hip ultrasound screening the decrease of the total number of interventions for all groups was 78.6%. Comparison of costs of the two observation periods showed an increase of all costs caused by DDH and CDH of 57.000 euro/ year for the time period between 1993 and 1998 which was mainly caused by the ultrasound screening programme. There was a significant reduction of costs regarding operative and non operative treatment for dysplastic hips from 410.000 euro (1978–1983) to 117.00 euro (1993–1998).

Conclusion: Initially there were higher costs caused by the screening method, but on the other hand total number and costs for operative and nonoperative treatment of dysplastic hips were significantly reduced by the universal ultrasound screening programme. In our mind patient’s and family distress and pain related to interventions performed for CDH and DDH justify the slight increase of costs caused by the universal screening programme. We therefore recommend universal hip ultrasound screening for neonates.

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: 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.

Background and purpose: Implantation of the femoral component at 10 to 15 degrees of anteversion is recommended in total hip arthroplasty. Surgical guidelines suggest that the lower leg be positioned horizontally or vertically with the knee flexed to 90° (figure of four). By constructing a perpendicular axis (a “figure-of-four” axis) to the lower leg, anteversion of the stem is approximated. This study was performed to validate the figure-of-four axis as a reliable intraoperative tool to approximate the retrocondylar line as reference for stem version.

Method: In 21 cadavers placed supine on an operating table, the lower legs were aligned to the horizontal plane. Using a box column drill, Steinmann nails were inserted perpendicular to the lower leg into the medial epicondyles. The Steinmann nails were replaced by cannulated titanium screws, representing the figure-of-four axis. The femoral neck axes, retrocondylar lines and the figure-of-four axes were determined using CT images of the specimen.

Results: The median version of the femoral neck axis was anteversion of 9.8° (IQR 4.5°–15.1°). The median figure-of-four axis showed a deviation of 0.5° (IQR −2.1°−2°) in relation to the retrocondylar line, whereas the median difference of the axis in relation to the femoral neck axis was 9.5° (IQR −13.6° – −2.1°).

Interpretation: The figure-of-four axis, being nearly parallel to the retrocondylar line, is a valid indirect method to determine stem version intraoperatively in patients without varus/valgus deviations of the knee.

Objective: To compare the cup and stem position in matched pairs of cadaveric hips performing a minimally invaisve total hip arthroplasty (MIS-THA) either by using manual guidance tools or by the STRYKER Hip-track Navigation System.

Background: Minimally invasive techniques are currently introduced to THA. Our workgroup has developed a direct anterior single incission approach. Special instruments have been designed for retraction and implantation. Instruments are navigable with the STRYKER hiptracksystem. Perfect positioning of the acetabular and femoral component are among the most important factors in THA. Malpositioning may result in significant clinical problems such as dislocation, impingement, limited range of motion or extensive wear.

Design/Methods: In twelve fixated human cadavers hemispherical pressfit cups (TRIDENT, Stryker, Alledale, NJ) and straight femoral components (ACCOLADE, Stryker, Allendale, NJ) were implanted. All implantation were done throught the minimally invasive direct anterior approach. On one side the surgery was performed with spezial MIS instruments. On the oposite side the navigation system was used for placement of the implants. The aim was to achieve an alignment for the cups with 45° of inclination and 15° of anteversion in reference to the frontal pelvic plane. For the stem the goal was to position the stem in 0° of varus/valgus relative to the proximal shaft axes. This plane and the resulting cup positions were measured on CT-scans with a 3D imaging software (Stryker-Leibinger, Freiburg, Germany).

Results: The Innsbruck MIS approach to the hip could be performed in all cases. For both groups cup and stem position where within the range of variation reported in the literature. Yet, variance of the deviation from the goal was higher in the conventional group for both inclination and anteversion with the medians for the navigated group for inclination, anteversion and stem position being closer to the goal then in the conventional group.

Conclusion: The described minimally invasive approach to the hip is feasible and renders results compareable to those reported for conventionally operated THA. By the use of the navigation system tested it is possible to increase placement precission