Introduction: The new anatomical adapted stem system OptanTM (Zimmer) is presented, showing the first mid-term-results for cemented and cementless fixation. Its cross-section in the proximal area corresponds with its antetorsion, anteversion and helitorsion, to the 3D-morphology of the proximal femur.

Material and Methods: 313 Optan stems (175 cemented, 148 cementless) were implanted in 306 patients (mean age 62.1 y. (20–74 y.), m/f-ratio 0,8). The clinical and radiological parameters for calculation of Harris Hip Score (HHS), Merle d’Aubigné (MD), WOMAC and periprosthetic bone reaction (Gruen et al.) were recorded. An implant migration analysis using two different biplanar radiographic digital measurement systems (DMA, UMA) was done also.

Results: The clinical results for latest follow up examination (5 and more y.p.o.) for cementless (cemented) Optan are: HHS mean (m) 97.6, standard deviation (SD) 7.32 (m 95.1, SD 9.85), MD m 17.6, SD 1.04 (m 17.1, SD 1.48), WOMAC m 1.44, SD 1.56 (m 1.75, SD 1.62). Cemented implantation shows a stable radiographic follow up regarding full cement mantle without any periprosthetic bone adaptations. The SD for the varus-valgus angle rises proportional to the thickness of the cement layer. Only little flattening of the calcar cortical bone (Z7b) could be seen in both, cemented and cementless Optan 2–3 years p.o.. No stem migration was evident in both fixation principles. No relevant osteolyses and cortical bone hypertrophies could be seen. 12 dislocations (closed reposition), 2 femoral fissures (all while cementless fixation), 2 septic loosenings and 1 aseptic loosening were documented till now. Radiographic results of cementless stem show a low rate (29,1%) of secondary endostal reactive line formation in the distal part of the stem (Z3,4,5) beginning 6–12 month postoperative, especially when drilling of femoral bone canal was done. When the distal part of the stem (Z3,5) was fixed directly to cortical bone little hypertrophy of the cortical bone gets relevant 4–5 years p.o. in a few cases.

Conclusions: Compared with other anatomical stems the cementless Optan shows excellent midterm results. The clinical results of the cemented fixation are not quite so good, this may be related to the older mean age of the patients with cemented stem fixation. Among other things, the development of the Optan-stem had the aim, to make an interoperative change of fixation technique easier. Using the same stem design the decision about the fixation type can be made intraoperatively in the last second.

Background Context: One of the main postulated basic principles of total disc replacement (TDR) is the preservation of flexion/extension ability. In neutral position the ideal disc prosthesis should not stay in maximal possible extension which would imply an impingement of the prosthesis. An impingement would cause shear strains on the prosthesis endplates which probably accelerate loosening. Moreover an additional extension ability from the neutral position would indicate no impingement in the facet joints in neutral position and a physiological movement capability.

Purpose: The purpose of study was to evaluate a possible impingement of the prosthesis or facet joints after TDR in neutral position.

Study design: Prospective evaluation of radiological outcome measures after total disc replacement.

Patient sample: The patients (19 female, 10 male) ranged from 29 to 56 years of age (mean: 42.46.5 years). The mean follow up interval averaged 13.2 months (range: 6 – 35 months). The diagnosis of degenerative disc disease was confirmed by MRI (black disc) and discography (positive „Memory pain“). Pain relief after facet joint infiltration was an exlucsion criteria. All patients had a single-level disc replacement (Prodisc II, Spine Solutions) with the same angulation (6).

Outcome measures: Evaluation of a possible impingement of the prosthesis and impingement of facet joints in neutral position.

Methods: A computer based analysis of pre- and postoperative lateral X-rays in neutral position and dynamic x-rays. The angulation of prosthesis in neutral position and the extension ability in dynamic x-rays were measured.

Results: 15 patients showed no extension ability on dynamic x-rays and 10 of these 15 patients had an impingement with maximum extension of the prosthesis on x-rays in neutral position. In the remaining 14 patients the extension ability averaged pre-/postoperatively 2.3/1.3 (p=0.115). In 4 of the 14 patients the pros-thesis showed an impingement in maximum extension and in 10 patients the prosthesis was not in maximum possible extension.

Conclusion: Due to the constrained design of the Pro-Disc an impingement is possible and was recognized in nearly 30% of the cases. The imbalance of flexion vs extension bending moments with increase in extension bending moments due to resection of the anterior longitudinal ligament and anterior anulus seems to be a possible explanation. It still remains unclear if an impingement will result in facet joint protection or will trigger a loosening of the implant. A prosthesis design which preserves the anterior longitudinal ligament would be probably a possible solution.

Objective: To report on health care utilization and associated cost for musculoskeletal conditions in Germany

Methods: As part of a Bone and Joint Decade project data were collected from governmental bodies, health insurance companies, pension funds, hospital discharge reports and other sources for the year 2002.

Results: According to the hospital discharge reports 17.8 % of all acute hospital days were due to musculoskeletal conditions or injuries, with joint disorders and back problems being the most frequent reasons for admission. 40% of all inpatient rehabilitation treatments were caused by musculoskeletal conditions. In the ambulatory segment, 27% of all patients visited during a 12 month period an orthopaedic surgeon or a rheuma-tologist. In addition, 37% of all GP consultations were due to musculoskeletal complains. These disorders were also responsible for about 40% of all days lost from work and 25% of all early retirements. The overall cost for musculoskeletal conditions in 1999 in Germany was about 40 Billion Euro, with back problems responsible for about 50%, and joint problems for another 30%.

Conclusion: Musculoskeletal conditions are the major cause of morbidity in the German society and substantially influence health and quality of life, with enormous cost to health systems. Considering the demographic changes immediate strategies have to be developed to address these problems, to prevent the diseases and to allow for early and appropriate care.

Introduction: Analgesia from controlled injections of local anaesthetic into the lumbar zygapohysial joint (z-joint) has been accepted as the standard for diagnosis of z-joint pain. Little is known about the placebo-response rate. Aim of this pilot study is to validate the fluoroscopically controlled z-joint-injection (ZJI) as an instrument for diagnosis of degenerative symptomatic z-joint disease.

Material and Methods: Due to degenerative lumbar spine syndrome 50 z-joints (L5/5: 27; L5/S1 23) were injected three times in a single blinded trial bilaterally. According to a randomisation protocol, using the oblique needle technique the ZJI were done with an local anaesthetic (LA: 1.5 ml 0.5% Scandicain), a saline placebo (sodium: 1.5ml 0.9% NaCl) and with no agent (sicca punction). The pain level before and after the injections (30 min, 1 and 2–3 hours) was documented by the patient on a 10pts.-VAS. Improvement in the pain level after an FJI is defined as responder. A responder reacts false positive if the degree of effectiveness of the placebo-FJI is the same or better than the response to LA. A patient reacts false negative if the pain diminution after LA application is lower than after placebo.

Results: Preliminary results regarding the reactions 30 min after injection are presented. 26% were non-responder and 52.9% LA-responder. The sicca response rate was 38%, for sodium it was 46%. Reaction after sicca-FJI was false positive in 24%, after sodium-FJI in 32% of cases. 38% reacted false negative to LA-injection. The order of the agent application didn’t have significant influence on the responder rates and also not on the extent of contradictory effects.

Conclusions: Despite numerous examinations none could sufficiently evaluate accurate reliable predictors for positive ZJI-responders till now. This is confirmed by our high LA-non-responder-rate of 48.1%. However, only a placebo injection can absolutely exclude a true placebo response. Placebo responses seem to be common. High specificity (minimization of the false positive results) and sensitivity (minimization of the false negative results) are characters for a good diagnostic test. In literature, the specificity of the intraarticular facet block as a diagnostic test for facet joint disease is currently unknown. Capsular rupture with epidural and periarticular diffusion is probably responsible for many false positive findings. Regarding our results, the validity of only one ZJI is not acceptable and shouldn’t be consulted as a diagnostic method for the identification of a facet joint syndrome, therefore. Pain relief after ZJI is a poor predictor of clinical outcome of posterolateral lumbosacral fusions when based on single blocks. Corresponding further examinations are necessary also regarding the ZJI-reliability.

Introduction: Filling of bone defects is a significant challenge in Orthopaedic Surgery. Human fresh-frozen allograft is still the most effective bone graft substitution material («gold standard»), guaranteeing all essential biological and physiochemical demands (osteogenic, osteoinductive, and osteoconductive) when the necessary amount of autologous bone is not available. Using donor screening recommendations, more than 50 % of potential donors have to be excluded. With increasing incidence for revision hip surgery and especially acetabular reconstructions, a hospital associated bone bank has difficulties meeting demand. The aim of this study is to evaluate the balance and resource utilisation of a hospital associated bone bank for fresh-frozen allografts and the correlation to commercial alternatives regarding cost effectiveness.

Method: For evaluation of resource utilisation and cost effectiveness of a hospital associated bone bank, all donation processes and the details of allograft use were analysed and summarized within a period of 30 months. Given the increasing disproportion of demand and availability, the reasons for exclusion, especially for exclusion during the preservation period, were carefully scrutinized. The costs of installation and maintenance of the bone bank, as well as all costs in the screening process were balanced to calculate the «per head»-price. The results were compared to commercial alternatives.

Results: Within the period of evaluation 632 femoral heads were available for donation. Through the screening process 359 femoral heads (56.8%) met at least one criterion for exclusion. At the end of the observation period of six months and after HIV retesting, 246 allografts met all criteria for use. The mean period between inclusion in the bone bank and release was 10.9 5.0 months (range 6.0–30.8).

50.8% of released allografts (125 heads) were used in revision arthroplasty. In spine surgery 83 allografts (33.7%) were implanted in spinal fusions and for cage filling during vertebral body replacement. Thirty-two grafts (13.0%) were used in miscellaneous surgeries with minor bone demand.

The costs per donation were 92, with personnel costs the price per head was 140. The price range for commercial alternatives starts at 100 for 1 cm.

Conclusion: A hospital associated bone bank for fresh-frozen allografts is still an effective and cost effective method to maintain material for bone defect filling. To meet demand, information and communication to donors has to be increased to get the HIV-retests. Additionally, division of donations into smaller portions helps to decrease waste in surgeries where less bone is required.

Purpose of the study: To find predictors for the clinical outcome in patients who underwent a high tibial osteotomy [HTO].

Method: Between 1984 and 1996 in 155 patients with genu varum a high tibial valgus osteotomy was performed. 133 HTOs were available for follow up at an average post-op time of 9.3 years (3,0 y). The morphology of the knee was evaluated by radiological (Kellgren) and arthroscopical classifications (Outerbridge). Survival time of HTO was estimated using Kaplan-Meier survivorship analysis. Patients outcome was evaluated using the WOMAC score. For statistical analysis Log-rank test and Wilcoxon-Mann Whitney U-Test were used.

Results: During follow up time 19.8% of patients needed a total knee arthroplasty. Survival rate of HTO was 95% after 5 years and 77% after 10 years. In the medial compartment of knee joints with a preoperative Outerbridge stage III/IV or Kellgren stage III/IV the survival rate of HTO was significantly lower when compared to stages I/II (p< 0,05).

Age, sex, dimension of the mechanical medial proximal tibial angle (mMPTA) and severity of arthrosis in the lateral compartment had no influence on survival rates. The pre-postoperative comparison of radiologically visible signs of arthrosis showed either no or only small progress. The patients who underwent a HTO had an average of 1,9 points on the WOMAC score (global index 0–10) which is a good to very good clinical outcome.

Conclusion: We identified the severity of the preoperative radiological signs of arthrosis and the extent of chondromalacia noted intraoperatively as predictors of survival rate.

Introduction: 3–5 year follow up results of the new anatomical adapted stem system OptanTM (Zimmer) are presented. Its cross-section in the proximal area corresponds with its antetorsion, anteversion and helitorsion, to the 3D-morphology of the proximal femur. Philosophy and aim of the cementless Optan-stem is a proximal fixation and force transmission in the femoral bone.

Material and Methods: Between July 1999 and Dec. 2001 242 Optan stems (122 cemented, 120 cementless) were implanted in 221 patients (mean age 62.1 y. (20–74 y.), m/ f-ratio 0,8). The clinical and radiological parameters for calculation of Harris Hip Score (HHS), Merle d’Aubigné (MD), WOMAC, periprosthetic bone reaction (Gruen et al.) and periarticular heterotopic bone formation (Brooker et al.) were recorded. An implant migration analysis using two different biplanar radiographic digital measurement systems (DMA, UMA) was done also.

Results: The clinical results for latest follow up examination (3–5 y.p.o.) for cementless (cemented) Optan are: HHS mean (m) 97.6, standard deviation (SD) 7.32 (m 95.1, SD 9.85), MD m 17.6, SD 1.04 (m 17.1, SD 1.48), WOMAC m 1.44, SD 1.56 (m 1.75 ,SD 1.62). Radiographic results of cementless stem show a low rate (29,1%) of secondary endostal reactive line formation in the distal part of the stem (Z3,4,5) beginning 6–12 month postoperative, especially when drilling of femoral bone canal was done. When the distal part of the stem (Z3,5) was fixed directly to cortical bone little hypertrophy of the cortical bone gets relevant 4–5 years p.o. in a few cases. Cemented implantation shows a stable radiographic follow up regarding cement mantle without any periprosthetic bone adaptations. The SD for the varus-valgus angle rises proportional to the thickness of the cement layer. Only little flattening of the calcar cortical bone (Z7b) could be seen in both, cemented and cementless Optan 2–3 years p.o.. No stem migration was evident in both fixation principles. No relevant osteoly-ses and cortical bone hypertrophies could be seen. 12 dislocations (closed reposition), 3 femoral fissures (all while cementless fixation), 3 septic loosenings and no aseptic loosening were documented till now.

Conclusions: Compared with other anatomical stems the cementless Optan shows similar excellent clinical mid-term results. The results of the cemented fixation are not quite so good, this may be related to the older mean age of the patients with cemented stem fixation. Till now, the radiographic results of cementless Optan doesn’t seem to contradict the philosophy of attempted physiological proximal force transmission to the femur. Among other things, the development of the Optan-stem had the aim, to make an interoperative change of fixation technique easier. Using the same stem design the decision about the fixation type can be made intraoperatively.

Objectives/background: Flexion Stability and Patella tracking after Total Knee Replacement is mainly influenced from the rotational alignment of the femoral component. Different implant philosophies use different landmarks for rotational alignment, as the epicondylar line, the posterior condyles or the anteroposterior line. An individual variation of the different landmarks is known from manual implantation an cadaver and CT studies.

The purpose of this study was to measure the variation of three different lines for femoral rotational alignment to show the possible difference and check the so far used values in manual instrumentation technique.

Design/methods: Using the Navitrack Navigation system we performed 100 consecutive TKRs. The landmarks for the 3 most common lines for rotational alignment of the femoral component has been probed.

The software calculated the position of the lines and the 3-dimensional ankle between the lines. Intraoperative snapshots were taken to postoperative data analysis of the numeric data.

Results: The mean difference between the ECL and the PCL was –0,96 (SD 3,64; range −10.7 − 5,9). In varus knees −0,2 (−6 −4,5) in valgus knees 1,4 (–10,7 – 5,9). ECL to the APC was in mean 88,83 (SD 7,23; range 100,8 – 71,9). In varus knees 91,3 (99 – 76,2) in valgus knees 83,8 (100,8 – 71,9).

Conclusions: Using a navigation system it is easy to perform an individual, intraoperative measurement of the relationship of different anatomical landmarks for rotational alignment of the femoral component. But the range of values shows that in the manual technique with fixed rotational alignment given by the instruments, there is a high risk for femoral rotational malalignment. The results depended on preoperative deformity could only be seen as a bias for higher variance in valgus knees. For the navigation procedures there is not one universal landmark which can be used. Furthermore the systems must be developed for intraoperative functional analysis, with integration of soft tissue balancing, to improve functional and long-term outcome in TKR.

Objectives/Background: Long-term outcome in THR is multifactorial influenced. Malpositioning leads to complications as early loosening, leg length difference or dislocation of the artificial joint. A proven factor for early losening is a misplacment of the center of rotation or varusposition of the stem. A higher luxation risk results out of high inclination and anteversion angles an reduced soft tissue tension.

Aim of this study was to prove the image free navigation software in the modular Navitrack-System to check the implant position based on anatomical intraoperative acquired data.

Design/Methods: In 35 consecutive cases we implantet the ACA screwcup and the Optan anatomical stem with use of the Navitrack navigation System. The software calculates al relevant data out of intraopertive probed landmarks. Intraoperative the shifting of the center of rotation, the cup anteversion and inclination, the stem inclination and torsion and the leglength shift is shown in real time. Intraoperative data were compared with postoperative position measurement in plain X-rays and in 15 patients in postoperative CT scans.

Results: In all cases navigated implantpositioning was possible. In 3 cases stem positioning was not possible cause of refference loosening. Mean inclination of the cup as shown in the Navigation System was 52 (range 45 – 58 ), mean anteversion was 11 (range -5 – 27). Mean postoperative inclination measured on postoperative X-Ray was 53,8 (range 49 – 60). The difference between the shown values from the CAS System to the postoperative X Ray for the inclination was 1,8 (range -9 – 6). The leg length difference on postoperative X-ray was in mean 3,1 mm, on screenshots 2,8 mm. The difference between screenshot and X ray was in mean 0,83 mm.

Conclusions: This study shows, that with the CT free software for the Navitrack-System reliable cup and stem navigation is possible. Whenever the hip joint allows to probe a spherical segment in the femoral head or acetabulum navigated THR is possible without the need of intraoperative fluoroscopy or preoperative CT scan. For leg length control and cup Inclination the data are still promising. Further investigation is necessary for stem axis and cup anteversion according to the navigation based reference coordinate system. Whenever no geometric sphere existent, e.g. severe hip dysplasia, the system must be developed as a hybrid system with CT (NMR) based cup and image-less stem navigation.

Background Context: Total disc replacement (TDR) gained enormous popularity as a treatment option for symptomatic degenerative disc disease in the last few years. But the impact of the prosthesis design on the segmental biomechanics in most instances still remains unclear. As TDR results in a distraction of the capsuloligamentous structures, the disc height seems to be of crucial importance for the further biomechanical function of the operated level. Yet the biomechanical role of disc height after TDR still remains unclear.

Purpose: The purpose of study was to evaluate the influence of prosthesis height after total disc replacement on: 1) the sagittal balance and 2) the range of motion.

Study design: A radiological and an in-vitro biomechanical study.

Method: 6 human, lumbar spines L4–L5 were tested in vitro.The segmental lordosis of the specimen were measured on plain radiographs and the range of motion was measured for all six degrees of freedom with a previously described spine tester. The segmental lordosis and the range of motion at level L4–L5 was evaluated for following settings: 1) intact state 2) after implantation of a prosthesis with 5mm endplate 3) after implantation of a prosthesis with 7mm endplate.

The prosthesis used was a prototyp and had a constrained design with a ball and socket principle.

Results: Even the implantation of the lowest possible prosthesis height (5mm endplate) resulted in an increase of segmental lordosis (intact: 6.9; 5mm endplate: 8.8; p=0,027). Using a higher prosthesis (7mm endplate) further increased the segmental lordosis (10.5, p=0.041). The implantation of the lowest prosthesis resulted in significant increase of movement capability compared to the intact status for flexion-extension (8.6 vs 11.4; p=0.046) and axial rotation (2.9 vs 5.1; p=0.028). Lateral bending did not changed significantly (9.4 vs 8.6; p=0.345). The implantation of the higher prosthesis (7mm endplate) resulted in similar movement capability compared to intact status for flexion-extension (8.4 vs 8.6; p=0.116) and axial rotation (3.3 vs 2.9; p=0.600). Lateral bending decreased significantly compared to the intact status (5.1 vs 8.6; p=0.028).

Conclusion: Total disc replacement with the lowest prosthesis height inherently increases segmental lordosis. Further increase of disc height results in a significant enhancement of segmental lordosis by decreasing the range of motion for all three degrees of freedom. Yet, methods for scheduling the ideal disc height preoperatively, to provide a physiological lordosis thereby maintaining physiological range of motion postoperatively, seems not to be established already.