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Introduction: In shoulder arthroplasty, ultra-high-molecular-weight polyethylene is used as standard material for glenoid components. The emergence of wear particles and their influence on the aseptic loosening of joint replacements are well known. The aim of the present study is to investigate the wear behaviour of the implant combinations as well as the size and morphology of the released wear particles from novel anatomic shoulder prosthesis. Here, the main interest lies on the influence of material inversion and different conformities on wear behaviour., Methods: Wear simulation was performed using a force-controlled joint simulator. The Modular-Shoulder-System from Permedica S.p.A. Orthopaedics was studied. Polyethylene wear was determined gravimetrically and was characterised by particle analysis. An abduction-adduction motion of 0°-90° lifting a load of 2 kg superimposed by an ante-/retroversion was chosen as the activity. In addition, an extreme test was performed to simulate subluxation of the joint., Results: The results showed a wear reduction of approximately 70% and a significant decrease in the total number of wear particles due to the material inversion on the bearing materials. No reduction of wear could be determined by varying the conformity of the bearing partners. In the simulated subluxation, the material inversion shows an increase in wear., Conclusion: Compared to similarly investigated systems, the Modular-Shoulder-System shows a reduction in wear. This reduction shows that material inversion may lead to a wear reduction. However, if subluxation of the humeral head occurs more frequently, increased material wear can be expected with the Modular-Shoulder-System. An influence of the conformity on the wear behaviour could not be determined., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

In cemented joint arthroplasty, state-of-the-art cementing techniques include high-pressure pulsatile saline lavage prior to cementation. Even with its outstanding importance in cementation, there are surprisingly few studies regarding the physical parameters that define pulsatile lavage systems. To investigate the parameters of impact pressure, flow rate, frequency and the cleaning effect in cancellous bone, we established a standardized laboratory model. Standardized fat-filled carbon foam specimens representing human cancellous bone were cleaned with three different high-pressure pulsatile lavage systems. Via CT scans before and after cleaning, the cleaning effect was evaluated. All systems showed a cleaning depth of at least 3.0 mm and therefore can be generally recommended to clean cancellous bone in cemented joint arthroplasty. When comparing the three lavage systems, the study showed significant differences regarding cleaning depths and volume, with one system being superior to its peer systems. Regarding the physical parameters, high impact pressure in combination with high flow rate and longer distance to the flushed object seems to be the best combination to improve the cleaning of cancellous bone and therefore increase the chances of a deeper cement penetration that is required in cemented joint arthroplasty. In summary, this study provides the first standardized comparison of different lavage systems and thus gives initial guidance on how to optimally prepare cancellous bone for cemented joint arthroplasty.

Background and purpose - Improving health care and demographic change have resulted in a steady increase in geriatric patients undergoing total hip (THA) and knee (TKA) arthroplasty. Postoperative delirium (POD) is a frequent and severe complication after major surgery. Therefore, we analyzed the impact of POD on outcome after THA and TKA.Patients and methods - In a consecutive series of 10,140 patients who had undergone elective THA or TKA between 2011 and 2020, rates of reoperation within 90 days, readmission within 90 days, complications, and responder rate as defined by the OMERACT-OARSI criteria were compared between patients with and without POD. Multivariable logistic regression models were used to assess the relationship between POD and other postoperative complications.Results - Patients with POD showed higher rates of reoperation (12% vs. 5%), readmission (15% vs. 5%), surgical complications (7% vs. 2%), non-surgical complications (8% vs. 4%), Clavien-Dindo IV° complications (10% vs. 2%) and transfusion (14% vs. 2%). POD led to lower responder rate (76% vs. 87%) 1 year after total joint replacement. All previous comparisons statistically significant. Multivariable logistic regression analyses revealed POD as an independent risk factor for reoperation (OR = 2; CI 1-3), readmission (OR = 2; CI 2-4) and Clavien-Dindo IV° complications (OR = 3; CI 2-5).Interpretation - POD is a serious problem in elective joint replacement. Affected patients suffer more complications and show poor patient-reported outcome 1 year postoperatively. Systematic prevention strategies and standardized therapy protocols are mandatory to avoid burden to patients and healthcare providers.

Informative, participatory clinical decision-making needs to combine both skills and expertise as well as current scientific evidence. The flood of digital information makes it difficult in everyday clinical practice to keep up to date with the latest publications. This article provides assistance for coping with this problem. A basic understanding of prior and posterior probabilities as well as systematic error (bias) makes it easier to weigh up the benefits and risks, e.g. of a (surgical) intervention compared to a nonsurgical treatment. Randomized controlled trials (RCT, with all modern modifications) deliver undistorted results but in orthopedic and trauma surgery can lead to a heavily selected nonrepresentative sample and the results must be confirmed or refuted by further, independent RCTs. Large-scale observational data (e.g. from registries) can be modelled in a quasi-experimental manner and accompany RCTs in health technology assessment., (© 2021. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Background: Metals and their ions allow specific modifications of the biological properties of bioactive materials that are intended for application in bone tissue engineering. While there is some evidence about the impact of particles derived from orthopedic Cobalt-Chromium-Molybdenum (Co-Cr-Mo) alloys on cells, there is only limited data regarding the influence of the essential trace element Mo and its ions on the viability, osteogenic differentiation as well as on the formation and maturation of the primitive extracellular matrix (ECM) of primary human bone marrow-derived stromal cells (BMSCs) available so far., Methods: In this study, the influence of a wide range of molybdenum (VI) trioxide (MoO 3 ), concentrations on BMSC viability was evaluated via measurement of fluorescein diacetate metabolization. Thereafter, the impact of three non-cytotoxic concentrations of MoO 3 on the cellular osteogenic differentiation as well as on ECM formation and maturation of BMSCs was assessed., Results: MoO 3 had no negative influence on BMSC viability in most tested concentrations, as viability was in fact even enhanced. Only the highest concentration (10 mM) of MoO 3 showed cytotoxic effects. Cellular osteogenic differentiation, measured via the marker enzyme alkaline phosphatase was enhanced by the presence of MoO 3 in a concentration-dependent manner. Furthermore, MoO 3 showed a positive influence on the expression of relevant marker genes for osteogenic differentiation (osteopontin, osteocalcin and type I collagen alpha 1) and on the formation and maturation of the primitive ECM, as measured by collagen deposition and ECM calcification., Conclusion: MoO 3 is considered as an attractive candidate for supplementation in biomaterials and qualifies for further research., (Copyright © 2021 Elsevier GmbH. All rights reserved.)

The modern cementing technique in cemented arthroplasty is a highly standardized and, therefore, safe procedure. Nevertheless, aseptic loosening is still the main reason for revision after cemented total knee or cemented total hip arthroplasty. To investigate whether an additional carbon dioxide lavage after a high-pressure pulsatile saline lavage has a positive effect on the bone-cement interface or cement penetration, we set up a standardized laboratory experiment with 28 human femoral heads. After a standardized cleaning procedure, the test implants were cemented onto the cancellous bone. Subsequently, the maximum failure load of the bone-cement interface was determined using a material testing machine to pull off the implant, and the cement penetration was determined using computed tomography. Neither the maximum failure load nor cement penetration into the cancellous bone revealed significant differences between the groups. In conclusion, according to our experiments, the additive use of the carbon dioxide lavage after the high-pressure pulsatile lavage has no additional benefit for the cleaning of the cancellous bone and, therefore, cannot be recommended without restrictions.

Purpose: Football players have a high risk of leg muscle injuries, especially when exposed to mental stress. Hence, this study investigated the musculoskeletal response of elite youth football players during highly dynamic movements under stress. The hypothesis is that mental stress reduces performance and changes the muscular forces exerted. Materials & methods: Twelve elite youth football players were subjected to mental stress while performing sports-specific change-of-direction movements. A modified version of the d2 attention test was used as stressor. The kinetics are computed using inverse dynamics. Running times and exerted forces of injury-prone muscles were analysed. Results: The stressor runs were rated more mentally demanding by the players (p = 0.006, r s   = 0.37) with unchanged physical demand (p = 0.777, r s   = 0.45). This resulted in 10% longer running times under stress (p < 0.001, d = -1.62). The musculoskeletal analysis revealed higher peak muscle forces under mental stress for some players but not for others. Discussion: The study shows that motion capture combined with musculoskeletal computation is suitable to analyse the effects of stress on athletes in highly dynamic movements. For the first time in football medicine, our data quantifies an association between mental stress with reduced football players' performance and changes in muscle force.

Introduction: The Hospital Frailty Risk Score (HFRS) is a validated risk stratification model referring to the cumulative deficits model of frailty. The purpose of this study was to evaluate the HFRS as a predictor of 90-day readmission and complications after revision total hip (rTHA) and knee (rTKA) arthroplasty., Methods: In a retrospective analysis of 565 patients who had undergone rTHA or rTKA between 2011 and 2019, the HFRS was calculated for each patient. Rates of adverse events were compared between patients with low and intermediate or high frailty risk. Multivariable logistic regression models were used to assess the relationship between the HFRS and post-operative adverse events., Results: Patients with intermediate or high frailty risk showed higher rates of readmission (30days: 23.8% vs. 9.9%, p = 0.006; 90days: 26.2% vs. 13.0%, p < 0.018), surgical complications (28.6% vs. 7.8%, p < 0.001), medical complications (11.9% vs. 1.0%, p < 0.001), other complications (28.6% vs. 2.3%, p < 0.001), Clavien-Dindo grade IV complications (14.3% vs. 4.8%, p = 0.009), and transfusion (33.3% vs. 6.1%, p < 0.001). Multivariable logistic regression analyses revealed a high HFRS as independent risk factor for surgical complications (OR = 3.45, 95% CI 1.45-8.18, p = 0.005), medical complications (OR = 7.29, 95% CI 1.72-30.97, p = 0.007), and other complications (OR = 14.15, 95% CI 5.16-38.77, p < 0.001)., Conclusion: The HFRS predicts adverse events after rTHA and rTKA. As it derives from routinely collected data, the HFRS could be implemented automated in hospital information systems to facilitate identification of at-risk patients., (© 2021. The Author(s).)

Introduction: Because of the ongoing discussion of imageless navigation in total knee arthroplasty (TKA), its advantages and disadvantages were evaluated in a large patient cohort., Methods: This retrospective analysis included 2464 patients who had undergone TKA at a high-volume university arthroplasty center between 2012 and 2017. Navigated and conventional TKA were compared regarding postoperative mechanical axis, surgery duration, complication rates, one-year postoperative patient-reported outcome measures (PROMs) (WOMAC and EQ-5D indices), and responder rates as defined by the criteria of the Outcome Measures in Rheumatology and Osteoarthritis Research Society International consensus (OMERACT-OARSI)., Results: Both navigated (1.8 ± 1.6°) and conventional TKA (2.1 ± 1.6°, p = 0.002) enabled the exact reconstruction of mechanical axis. Surgery duration was six minutes longer for navigated TKA than for conventional TKA (p < 0.001). Complication rates were low in both groups with comparable frequencies: neurological deficits (p = 0.39), joint infection (p = 0.42 and thromboembolic events (p = 0.03). Periprosthetic fractures occurred more frequently during conventional TKA (p = 0.001). One-year PROMs showed excellent improvement in both groups. The WOMAC index was statistically higher for navigated TKA than for conventional TKA (74.7 ± 19.0 vs. 71.7 ± 20.7, p = 0.014), but the increase was not clinically relevant. Both groups had a similarly high EQ-5D index (0.23 ± 0.24 vs. 0.26 ± 0.25, p = 0.11) and responder rate (86.5% [256/296] vs. 85.9% [981/1142], p = 0.92)., Conclusion: Both methods enable accurate postoperative leg alignment with low complication rates and equally successful PROMs and responder rates one year postoperatively., Level of Evidence: III. Retrospective cohort study., (© 2021. The Author(s).)

Medical knowledge is rapidly expanding but which research results in orthopedics and trauma surgery are actually suitable to change treatment decisions in the daily routine? Evidence-based medicine is a process to search for reliable answers to this and in the assessment of scientific data relies on an individual systematic evaluation with quality criteria and defined statistics. The core procedure is to filter out the true patient benefits from study results by a structured analysis in order to derive an algorithm to solve the clinical problem. The clinical expertise, the knowledge and the strength of judgement of orthopedic and trauma surgeons play a central role in the assessment of the calculated evidence-based key figures., (© 2021. Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Background and purpose - There is growing evidence that hypoproteinemia is an important risk factor for adverse events after surgery. Less is known about the impact of vitamin deficiency on postoperative outcome. Therefore we evaluated the prevalence and impact of malnutrition and vitamin deficiency in geriatric patients undergoing elective orthopedic surgery.Patients and methods - In a retrospective analysis of 599 geriatric patients who had undergone elective orthopedic surgery in 2018 and 2019, hypoproteinemia, and deficiency of vitamin D, vitamin B12, and folate were assessed. Reoperation rates, readmission rates, complication rates, and transfusion rates were compared between malnourished patients and patients with normal parameters. Multivariable logistic regression models were used to assess the relationship between malnutrition and postoperative adverse events, controlling for confounding factors such as age, sex, diabetes mellitus, and frailty.Results - Patients with malnutrition showed a higher rate of reoperation (13% vs. 5.5%; p = 0.01) and exhibited more wound-healing disorders (7.4% vs. 1.3%, p = 0.001) as well as Clavien-Dindo IV° complications (7.4% vs. 2.4%; p = 0.03). Deficiency of vitamin D led to a higher rate of falls (8.4% vs. 2.9%, p = 0.006). Deficiency of vitamin B12 and folate did not affect postoperative adverse events. Although correlated to frailty (p = 0.004), multivariable regression analysis identified malnutrition as independent risk factor for reoperation (OR 2.6, 95% CI 1.1-6.2) and wound healing disorders (OR 7.1, CI 1.9-26).Interpretation - Malnutrition is common among geriatric patients undergoing elective orthopedic surgery and represents an independent risk factor for postoperative adverse events.

Background: Models for risk stratification and prediction of outcome, such as the Charlson Comorbidity Index (CCI), the Elixhauser Comorbidity Method (ECM), the 5-factor modified Frailty Index (mFI-5), and the Hospital Frailty Risk Score (HFRS) have been validated in orthopedic surgery. The aim of this study is to compare the predictive power of these models in total hip and knee replacement., Methods: In a retrospective analysis of 8250 patients who had undergone total joint replacement between 2011 and 2019, CCI, ECM, mFI-5, and HFRS were calculated for each patient. Receiver operating characteristic curve plots were generated and the area under the curve (AUC) was compared between each score with regard to adverse events such as transfusion, surgical, medical, and other complications. Multivariate logistic regression models were used to assess the relationship among risk stratification models, demographic factors, and postoperative adverse events., Results: In prediction of surgical complications, HFRS performed best (AUC: 0.719, P < .001), followed by ECM (AUC: 0.578, P < .001), mFI-5 (AUC: 0.564, P = .003), and CCI (AUC: 0.555, P = .012). With regard to medical complications, other complications, and transfusion, HFRS also was superior to ECM, mFI-5, and CCI. Multivariate logistic regression analyses revealed HFRS as an independent risk stratification model associated with all captured adverse events (P ≤ .001)., Conclusion: The HFRS is superior to current risk stratification models in the context of total joint replacement. As the HRFS derives from routinely collected administrative data, healthcare providers can identify at-risk patients without additional effort or expense., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Computer-assisted surgery represents a relatively novel treatment option in total hip arthroplasty, which has been supported by the technological progress over the latest decades. Navigation and robotics enable increasing the precision of cup positioning, as well as successful biomechanical restoration of leg length and offset. However, the intended target area is still one of debate in literature. Besides the learning curve, the use of navigation and robotics requires additional time and financial expense, which has not yet been addressed in the German healthcare system. This is one reason why computer-assisted surgery has not fully attained everyday routine. The number of comparative studies is limited, but the results are promising. However, if these surrogate measures will end in reduced revision rates or better outcome is unclear. Further prospective studies and register analysis might illuminate the potential benefit of navigation and robotics.

Background: The success of primary total hip replacement (THR) is predominately determined by the primary stability of the implant and the restoration of the patient-specific joint biomechanics. The three-dimensional (patho-) anatomy, size, geometry, and shape of the acetabulum and proximal femur is highly variable in patients with advanced hip osteoarthritis. Accurate preoperative planning is an essential prerequisite for all replacement procedures., Current Situation: Current data demonstrates clinical advantages for patient-specific reconstruction of functional joint geometry via surrogate parameters (offset and leg length). Frequently cited "target zones" for the positioning and orientation of the cup are increasingly in the focus of scientific discussion, as individually adjusted target zones for implant positioning allow for a potential reduction of impingement risk. Patients with spinal fusions or pathologic spinopelvic alignment require that particular attention be paid to patient-specific preoperative preparation, the surgical technique, and implant selection in order to reduce the risk of postoperative instability.

Background: The Hospital Frailty Risk Score (HFRS) is a validated geriatric comorbidity measure derived from routinely collected administrative data. The purpose of this study is to evaluate the utility of the HFRS as a predictor for postoperative adverse events after primary total hip (THA) and knee (TKA) arthroplasty., Methods: In a retrospective analysis of 8250 patients who had undergone THA or TKA between 2011 and 2019, the HFRS was calculated for each patient. Reoperation rates, readmission rates, complication rates, and transfusion rates were compared between patients with low and intermediate or high frailty risk. Multivariate logistic regression models were used to assess the relationship between the HFRS and postoperative adverse events., Results: Patients with intermediate or high frailty risk showed a higher rate of reoperation (10.6% vs 4.1%, P < .001), readmission (9.6% vs 4.3%, P < .001), surgical complications (9.1% vs 1.8%, P < .001), internal complications (7.3% vs 1.1%, P < .001), other complications (24.4% vs 2.0%, P < .001), Clavien-Dindo grade IV complications (4.1% vs 1.5%, P < .001), and transfusion (10.4% vs 1.3%, P < .001). Multivariate logistic regression analyses revealed a high HFRS as independent risk factor for reoperation (odds ratio [OR] = 2.1; 95% confidence interval [CI], 1.46-3.09; P < .001), readmission (OR = 1.78; 95% CI, 1.21-2.61; P = .003), internal complications (OR = 3.72; 95% CI, 2.28-6.08; P < .001), surgical complications (OR = 3.74; 95% CI, 2.41-5.82; P < .001), and other complications (OR = 9.00; 95% CI, 6.58-12.32; P < .001)., Conclusion: The HFRS predicts adverse events after THA and TKA. As it derives from routinely collected data, the HFRS enables hospitals to identify at-risk patients without extra effort or expense., Level of Evidence: Level III-retrospective cohort study., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Purpose: Polyethylene (PE) wear remains a common reason for revision surgery following total hip arthroplasty (THA). An established treatment method is isolated liner exchange in a well-fixed acetabular cup and entails a known high risk of hip dislocation after revision surgery. The purpose of this retrospective study was to determine the rate of hip dislocation after liner exchange., Methods: Patients were included if (1) the PE liner was removable, (2) the acetabular shell was stable with acceptable orientation, (3) no osteolysis around the acetabular cup was found and (4) no dislocation of the THA occurred before revision surgery. We reviewed medical histories and performed radiological measurements using Einzel-Bild-Röntgen-Analyse (EBRA) software. EBRA measurements and statistical investigations were performed by two independent investigators., Results: A total of 82 patients were included in our study. Mean follow-up was six (range: 3.6-9.9) years. In 13 (15.8%) patients THA dislocations occurred at a mean postoperative period of 20.2 (range: 1-44) weeks after revising the PE liner. This is equivalent to an absolute risk increase of 16% after revision surgery, which results in a number needed to harm of 6. This means that every sixth patient with isolated liner exchange can expect to experience dislocation due to wear., Conclusion: In conclusion, isolated exchange of the polyethylene liner because of wear showed a high risk of dislocation and further cup revision. Our results suggest that the threshold for revising well-fixed components in the case of liner wear should be lowered., Trial Registration Number and Date of Registration: Number: 20140710-1012 and Date: 2016-03-09.

The optimal 3D positioning of the prosthesis components is of great importance for the stability and function of a total hip endoprosthesis. Pelvic tilt has a particular influence on the position of the implant. In order to use intraoperatively the knowledge on pelvic kinematics gained through preoperative imaging procedures and movement analyses, "image-based" and "image-free" robotic and navigation procedures are available. With the "image-based" procedures, a 3D CT scan serves as the surgeon's basis for operative planning. The "image-free" procedures are based on the principles of stereotaxy. In the future, information about static and dynamic pelvic tilt will be conntected with navigation and robotic systems for total hip arthroplasty. Along with intraoperative data a patientindividual optimized implant position can be achieved.

Offset restoration in total hip arthroplasty (THA) is associated with postoperative range of motion (ROM) and gait kinematics. We aimed to research into the impact of high offset (HO) and standard stems on postoperative ROM. 121 patients received cementless THA through a minimally-invasive anterolateral approach. A 360° hip ROM analysis software calculated impingement-free hip movement based on postoperative 3D-CTs compared to ROM values necessary for activities of daily living (ADL). The same model was then run a second time after changing the stem geometry between standard and HO configuration with the implants in the same position. HO stems showed higher ROM for all directions between 4.6 and 8.9° (p < 0.001) compared with standard stems but with high interindividual variability. In the subgroup with HO stems for intraoperative offset restoration, the increase in ROM was even higher for all ROM directions with values between 6.1 and 14.4° (p < 0.001) compared to offset underrestoration with standard stems. Avoiding offset underrestoration resulted in a higher amount of patients of over 20% for each ROM direction that fulfilled the criteria for ADL (p < 0.001). In contrast, in patients with standard stems for offset restoration ROM did increase but not clinically relevant by offset overcorrection for all directions between 3.1 and 6.1° (p < 0.001). Offset overcorrection by replacing standard with HO stems improved ROM for ADL in a low number of patients below 10% (p > 0.03). Patient-individual restoration of offset is crucial for free ROM in THA. Both over and underrestoration of offset should be avoided.

Purpose: Valgus deformity presents a particular challenge in total knee arthroplasty. This condition regularly leads to contractures of the lateral capsular ligament complex and to overstretching of the medial ligamentous complex. Reconstruction of the knee joint kinematics and anatomy often requires lateral release. However, data on how such release weakens the stability of the knee are missing in the literature. This study investigated the effects of sequential lateral release on the collateral stability of the ligament complex of the knee in vitro., Methods: Ten knee prostheses were implanted in 10 healthy cadaveric knee joints using a navigation device. Soft tissue lateral release consisted of five release steps, and stiffness and stability were determined at 0, 30, 60 and 90° flexion after each step., Results: Soft tissue lateral release increasingly weakened the ligament complex of the lateral compartment. Because of the large muscular parts, the release of the iliotibial band and the M. popliteus had little effect on the stability of the lateral and medial compartment, but release of the lateral ligament significantly decreased the stability in the lateral compartment over the entire range of motion. Stability in the medial compartment was hardly affected. Conversely, further release of the posterolateral capsule and the posterior cruciate ligament led to the loss of stability in the lateral compartment only in deep flexion, whereas stability decreased significantly in the medial compartment., Conclusion: Our study shows for the first time the association between sequential lateral release and stability of the ligamentous complex of the knee. To maintain the stability, knee surgeons should avoid releasing the entire lateral collateral ligament, which would significantly decrease stability in the lateral compartment.

Persistent pain around the greater trochanter is a common complication after total hip arthroplasty. Restoration of biomechanics such as leg length, femoral und acetabular offset is crucial in THA. The purpose of this study was to evaluate postoperative differences of these parameters after THA and to analyze their association to greater trochanteric pain syndrome. Furthermore, we aimed to evaluate the clinical relevance of trochanteric pain syndrome compared to patient reported outcome measures. 3D-CT scans of 90 patients were analyzed after minimalinvasive total hip arthroplasty and leg length, femoral and acetabular offset differences were measured. Clinical evaluation was performed three years after THA regarding the presence of trochanteric pain syndrome and using outcome measures. Furthermore, the patients' expectation were evaluated. Patients with trochanteric pain syndrome showed a higher absolute discrepancy of combined leg length, femoral and acetabular offset restoration compared to the non-operated contralateral side with 11.8 ± 6.0 mm than patients without symptoms in the trochanteric region with 7.8 ± 5.3 mm (p = 0.01). Patients with an absolute deviation of the combined parameters of more than 5 mm complained more frequently about trochanteric symptoms (29.2%, 19/65) than patients with a biomechanical restoration within 5 mm compared to the non-affected contralateral side (8.0%, 2/25, p = 0.03). Clinical outcome measured three years after THA was significantly lower in patients with trochanteric symptoms than without trochanteric pain (p < 0.03). Similarly, fulfillment of patient expectations as measured by THR-Survey was lower in the patients with trochanteric pain (p < 0.005). An exact combined restoration of leg length, acetabular and femoral offset reduces significantly postoperative trochanteric pain syndrome and improves the clinical outcome of the patients.

Background: After total hip arthroplasty (THA), objective postoperative quality control is done via X‑rays by as component position assessment. The cup position is defined by its version and inclination. However, there is a discrepancy between radiographically measured and true (anatomic) cup position, which may lead to misinterpretation., Methods: To visualize the discrepancy between true and radiographically measured cup position, in this video, a cup holder was used to set the angular cup version and inclination. Hereby, the cup position (anteversion and inclination) can be characterized in its radiographic and anatomic definition in greater detail. The viewer of this video should receive an impression as to when radiographically measured cup angles must be considered with caution., Results: In a simultaneous X‑ray and image sequence, this video shows decreased radiographic inclination measurement with increasing anterior rotation of the cup exceeding 20° of anteversion, yet with unchanged true inclination on the cup holder. Isolated consideration of the radiographic angles of anteversion and inclination may cause misinterpretation of true cup position. In pectoral illustration we show that variations in cup version and inclination may remain undetected when considering isolated the radiographic cup parameters., Conclusion: True cup position in its anatomical definition can be calculated from the radiographically measured position. For this purpose, both cup parameters (radiographic anteversion and radiographic inclination) have to be taken into account.

The exact reconstruction of the tibial plateau and articular surface is the main operative aim in the treatment of tibial plateau depression fractures. For selected cases, a novel technique with the use of balloon tibioplasty in combination of bioabsorbable calcium phosphate cement is available. In this study, the first objective was to answer the question whether the clinical outcome parameters after balloon tibioplasty are comparable to open reduction procedures described in the literature. Secondly, we asked whether the cement absorption is safe in relation to adverse effects like osteolysis and measured the absorption ability during the bone conversion process in the proximal tibia bone. Eight patients (mean age 54 years; 4 males and 4 females) received the abovementioned surgical procedure. Mean follow-up period was 27 months. This study evaluated clinical outcome and radiological measured cement absorption within the postoperative course. Cement absorption was measured on X-rays and calculated based on the greatest extend on anterior-posterior and lateral view radiographs just after the operation on the latest available follow-up. WOMAC score showed a mean of 93. Radiologic absorption was 1/5 at a mean of 18 months. No osteolysis reaction was seen surrounding the cement. This far, promising clinical and radiological results have been shown with WOMAC scores comparable to the results of noninjured knees. The indication for this relatively new technique is restricted to isolated depression fractures. It is a useful tool to facilitate the reduction of select depressed tibial fractures. The radiologic absorption effect seems to be quite fast in bone remodeling and safe without any osteolysis or osseous reaction.

Purpose: In revision hip arthroplasty, custom-made implants are one option in patients with acetabular Paprosky III defects., Methods: In a retrospective analysis, we identified 11 patients undergoing cup revision using a custom-made implant. The accuracy of the intended position of the implant was assessed on post-operative 3D CT and compared to the pre-operative 3D planning in terms of inclination, anteversion, and centre of rotation. In addition, the accuracy of post-operative plain radiographs for measuring implant position was evaluated in relation to the 3D CT standard., Results: We found a mean deviation between the planned and the final position of the custom-made acetabular implant on 3D CT of 3.6° ± 2.8° for inclination and of - 1.2° ± 7.0° for anteversion, respectively. Restoration of center of rotation succeeded with an accuracy of 0.3 mm ± 3.9 mm in the mediolateral (x) direction, - 1.1 mm ± 3.8 mm in the anteroposterior (y) direction, and 0.4 mm ± 3.2 mm in the craniocaudal (z) direction. The accuracy of the post-operative plain radiographs in measuring the position of the custom-made implant in relation to 3D CT was 1.1° ± 1.7° for implant inclination, - 2.6° ± 1.3° for anteversion and 1.3 mm ± 3.5 mm in the x-direction, and - 0.9 mm ± 3.8 mm in the z-direction for centre of rotation., Conclusion: Custom-made acetabular implants can be positioned with good accuracy in Paprosky III defects according to the pre-operative planning. Plain radiographs are adequate for assessing implant position in routine follow-up.

Purpose: The purpose of this study was to investigate the effects of sequential medial release on the stiffness and collateral stability of the ligament complex of the knee. Irrespective of the implantation technique used, varus deformity frequently requires release of the capsular ligament complex. Yet, no data are available on how stiffness and stability of the knee ligament complex are weakened by such release., Methods: After total knee arthroplasty, ten healthy Thiel-fixed knee joints were subjected to sequential medial release consisting of six release steps. After each step, stiffness and stability were determined at 0°, 30°, 60°, and 90°., Results: Sequential medial release increasingly weakened the ligament complex. In extension, release of the anteromedial tibial sleeve 4 cm below the joint line already weakened the ligament complex by approximately 13%. Release 6 cm below the joint line reduced stiffness and stability by 15-20% over the entire range of motion. After detachment of the medial collateral ligament, stability was only about 60% of its initial value., Conclusion: Our study showed for the first time the association between medial release and stiffness and stability of the knee ligament complex. To maintain stability, vigorous detachment of the knee ligament complex should be avoided. Release of the anteromedial tibial sleeve already initiates loss of stability. The main stabiliser is the medial ligament, which should never be completely detached., Level of Evidence: IV.

Restoration of biomechanics is crucial in total hip arthroplasty, in order to ensure a free postoperative range of motion for activities of daily life. Failure may result in impingement and thus instability, limping and finally patient dissatisfaction. In daily practice, preoperative templating is usually performed on magnification-corrected, plain radiographs of the hip. Due to the divergence of the X-ray beams and the position of the pelvis in relation to the film, measurements on plain radiographs are susceptible to error. Whereas leg length measurements are highly accurate, femoral offset is frequently underestimated on plain radiographs. The benchmark for acceptable postoperative leg length and offset differences is still under debate in the literature. However, discrepancies of 1 cm in relation to the non-affected, contralateral side should not be exceeded. Gait analysis is able to detect even differences in leg length and offset above 5 mm due to altered gait kinematics. For intraoperative control of leg length and offset, a variety of different methods have been described in the literature. Beside alignment guides, rulers and other tools, intraoperative fluoroscopy and computer-guided navigation allow the surgeon to intraoperatively analyse leg length and offset changes. Both techniques show high accuracy, although the precision is higher for navigation with a reduced number of outliers. For measurement of stem torsion, computed tomography is the gold standard. However, stem torsion can also be evaluated on plain hip radiographs by measuring the projected prosthetic neck-stem angle. Native femoral anteversion can be assessed by the size of the lesser trochanter. Since the version of the femoral stem can highly vary from the native femoral anteversion, the Isthmus Ratio (iRatio) - the relationship between canal isthmus and calcar isthmus in the anteroposterior and Lauenstein view - helps to predict the torsion of the final intraoperative stem., Competing Interests: T. Renkawitz erhielt Forschungsmittel von DePuy International, Otto Bock Foundation, Deutsche Arthose Hilfe. T. Renkawitzʼ Forschungsgruppe „Patientenindividuelle Endoprothetik“ wird unterstützt vom Bundesministerium für Bildung und Forschung (BMBF, Nr. 01EZ0915). J. Grifka erhielt Forschungsmittel von MSD, Novartis, De Puy, Otto Bock Foundation. Weitere finanzielle Unterstützung kam von De Puy, Orthotech, Ozo-zours, Fischer Fussfit, Urban & Kemmler.T. Renkawitz erhielt Forschungsmittel von DePuy International, Otto Bock Foundation, Deutsche Arthose Hilfe. T. Renkawitzʼ Forschungsgruppe „Patientenindividuelle Endoprothetik“ wird unterstützt vom Bundesministerium für Bildung und Forschung (BMBF, Nr. 01EZ0915). J. Grifka erhielt Forschungsmittel von MSD, Novartis, De Puy, Otto Bock Foundation. Weitere finanzielle Unterstützung kam von De Puy, Orthotech, Ozo-zours, Fischer Fussfit, Urban & Kemmler., (Georg Thieme Verlag KG Stuttgart · New York.)

A key requirement in both native knee joints and total knee arthroplasty is a stable capsular ligament complex. However, knee stability is highly individual and ranges from clinically loose to tight. So far, hardly any in vivo data on the intrinsic mechanical of the knee are available. This study investigated if stiffness of the native ligament complex may be determined in vivo using a standard knee balancer. Measurements were obtained with a commercially available knee balancer, which was initially calibrated in vitro. 5 patients underwent reconstruction of the force-displacement curves of the ligament complex. Stiffness of the medial and lateral compartments were calculated to measure the stability of the capsular ligament complex. All force-displacement curves consisted of a non-linear section at the beginning and of a linear section from about 80 N onwards. The medial compartment showed values of 28.4 ± 1.2 N/mm for minimum stiffness and of 39.9 ± 1.1 N/mm for maximum stiffness; the respective values for the lateral compartment were 19.9 ± 0.9 N/mm and 46.6 ± 0.8 N/mm. A commercially available knee balancer may be calibrated for measuring stiffness of knee ligament complex in vivo, which may contribute to a better understanding of the intrinsic mechanical behaviour of knee joints.

Choosing the appropriate patient for surgery is crucial for good outcome in total hip arthroplasty (THA). Therefore, parameters predicting outcome preoperatively are of major interest. In the current study, we compared the predictive power of different presurgical measures in minimally invasive THA. In the course of a prospective clinical trial preoperative HOOS, EQ-5D and SF-36 were obtained in 140 patients undergoing THA. Responder rate was defined by the modified OMERACT-OARSI criteria at six-month-, one-year, two-year, and three-year follow-up. Logistic regression was performed to compare the different questionnaires regarding their power of predicting positive responders. ROC-curve analysis was used to define benchmarks in preoperative measures associated with good outcome. Preoperative HOOS (p<0.001), EQ-5D (p=0.007), and PCS of SF-36 (p<0.001) were higher in responders than in nonresponders whereas no differences between responders and nonresponders were found for preoperative MCS (p=0.96) of SF-36. However, preoperative HOOS revealed best predictive power (OR=0.84 95%CI=0.78-0.90, p<0.001, Pseudo R-Squared according to Nagelkerke=0.48, effect size according to Cohen=0.96) compared to all other preoperative measures. Multivariable analysis confirmed preoperative HOOS as an independent parameter correlating with postoperative responder status (OR=0.76, 95% CI=0.66-0.88, p<0.001). In ROC-curve analysis nonresponders were identified with a sensitivity of 91.7% and specificity of 68.9% using a cutoff in preoperative HOOS of 40.3. Presurgical HOOS can predict outcome in THA better than other preoperative outcome measures. Patients with a preoperative HOOS value less than 40.3 have the highest probability of a positive response in terms of pain and function after THA.

This study evaluates how medical students rate the different types of teaching materials and methods available as well as possible gender-specific differences in the use of such materials. In this descriptive, cross-sectional study a questionnaire with short, one-dimensional questions with a 4-step Likert scale was developed by a presurvey within 493 students (4th year) at a University Medical School (January-December 2015). The anonymous survey was performed from July 2016 to February 2017 with 252 students within an orthopaedic surgery course at University Medical School. After exclusion of (1) nonnative speakers and (2) incomplete forms, 233 samples were included. Practical education was regarded as the most important (n=160/68.7%) teaching method followed by Internet research (n=147/63.1%) as the most important teaching material, while traditional frontal teaching (n=19/8.2%) and e-books (n=11/4.7%) ranked last. The evaluation of gender-specific differences in the use of teaching materials showed that female students prefer to highlight text (p<0.0001) as well as a trend to Internet research (p=0.053) and small-group teaching (p=0.057). Despite some gender-specific differences, traditional learning methods retain their importance besides new learning possibilities such as Internet research.

Background: In total hip arthroplasty, inadequate femoral component positioning can be associated with instability, impingement and component wear and subsequently with patient dissatisfaction. In this study, we investigated the influence of femoral neck resection height on the final three-dimensional position of a collarless straight tapered stem (Corail ® ). We asked two questions-(1) is neck resection height correlated with version, tilt, and varus/valgus alignment of the femoral component, and (2) dependent on the resection height of the femoral neck, which area of the stem comes into contact with the femoral cortical bone?, Materials and Methods: Three-dimensional computed tomography scans of 40 patients who underwent minimally invasive, cementless total hip arthroplasty were analyzed retrospectively. We analyzed the relationship between femoral neck resection height and three-dimensional alignment of the femoral implant, as well as the contact points of the implant with the femoral cortical bone. This investigation was approved by the local Ethics Commission (No.10-121-0263) and is a secondary analysis of a larger project (DRKS00000739, German Clinical Trials Register May-02-2011)., Results: Mean femoral neck resection height was 10.4 mm (± 4.8) (range 0-20.1 mm). Mean stem version was 8.7° (± 7.4) (range - 2° to 27.9°). Most patients had a varus alignment of the implant. The mean varus/valgus alignment was 1.5° (± 1.8). All 40 patients (100%) had anterior tilt of the implant with a mean tilt of 2.2° (± 1.6). Femoral neck resection height did not correlate with stem version, varus/valgus alignment, or tilt. Independent from femoral neck resection height, in most patients the implant had contact with the ventral and ventromedial cortical bone in the upper third (77.5%) and the middle third (52.5%). In the lower third, the majority of the implants had contact with the lateral and dorsolateral cortical bone (92.5%)., Conclusion: Femoral neck resection height ranging between 0 and 20.1 mm does not correlate with the final position of a collarless straight tapered stem design (Corail ® )., Level of Evidence: Level 3.

Revisions after total joint replacement increase constantly. In the current study, we analyzed clinical outcome, complication rates, and cost-effectiveness of revision arthroplasty. In a retrospective analysis of 162 revision hip and knee arthroplasties from our institutional joint registry responder rate, patient-reported outcome measures (EQ-5D, WOMAC), complication rates, and patient-individual charges in relation to reimbursement were compared with a matched control group of primary total joint replacements. Positive responder rate one year postoperatively was lower for revision arthroplasties with 72.9% than for primary arthroplasties with 90.1% (OR=0.30, 95%CI=0.18-0.59, p=0.001). Correspondingly, improvement in patient-reported outcome measures one year after surgery was lower in revision than in primary joint arthroplasty with EQ-5D 0.19±0.25 to 0.30±0.24 (p<0.001) and WOMAC 24.3±30.3 to 41.2±21.3 (p<0.001). Infection rate was higher in revision (6.8%) compared to primary replacements (0%, p=0.001). Mean charges in revision arthroplasty were 76.0% higher than in matched primary joint replacements (7110.8±2249.4$ to 4041.1±975.7$, p<0.001), whereas reimbursement was only 23.6% higher (9243.3±2258.4$ in revision and 7477.9±703.1$ in primary arthroplasty, p<0.001). Revision arthroplasty is associated with lower outcome and higher infection rate compared to primary replacements. The high financial expense of revision arthroplasty is only partly covered by a higher reimbursement.

Introduction: In anteposterior (AP) radiographs, cup position in total hip arthroplasty and acetabular anatomy in hip-preserving surgery are highly influenced by pelvic tilt. The sagittal rotation of the anterior pelvic plane is an important measurement of pelvic tilt during hip surgery. Thus, correct evaluation of cup position and acetabular parameters requires the assessment of pelvic tilt in AP radiographs., Methods: Changes in pelvic tilt inversely change the height of the lesser pelvis and the obturator foramen in AP radiographs. Tilt ratios were calculated by means of these two parameters in simulated radiographs for ten male and ten female pelvises in defined tilt positions. A tilt formula obtained by exponential regression analysis was evaluated by two blinded investigators by means of 14 simulated AP radiographs of the pelvis with pelvic tilts ranging from + 15° to - 15°., Results: No differences were found between male and female tilt ratios for each 5° step of simulated pelvic tilt. Pelvic tilt and tilt ratios correlated exponentially. Using the tilt formula, the two blinded investigators were able to assess pelvic tilt with high conformity, a mean relative error of + 0.4° (SD ± 4.6°), and a mean absolute error of 3.9° (SD ± 2.3°). Neutral pelvic tilt is indicated by a tilt ratio of 0.5 when the height of the lesser pelvis is twice the height of the obturator foramen., Conclusion: The analysis and interpretation of cup position and acetabular parameters may be improved by our method for assessing pelvic tilt in AP radiographs.

Equalization of biomechanical differences is a major goal in total hip arthroplasty (THA). In the current study we compared the accuracy of restoring leg length and offset using imageless navigation with an osseous fixed pin to a femoral pinless device in 97 minimally invasive THAs through an anterolateral approach in the lateral decubitus position. Leg length and offset differences were evaluated on magnification-corrected radiographs by a blinded observer. A postoperative mean difference of -0.9 mm (95% CI -2.8 mm to 1.1 mm, p = 0.38) between pinless navigation and navigation with a fixed pin was observed for leg length and that of -2.4 mm (95% CI -3.9 mm to -0.9 mm, p = 0.002) was observed for offset, respectively. The number of patients with a residual difference below 5 mm after THA was higher if using a fixed pin than in pinless navigation for both leg length (98.2%, 54/55 to 50.0%, 21/42, p < 0.001) and offset (100.0%, 55/55 to 71.4%, 30/42, p < 0.001). Imageless navigation is a feasible method in intraoperative control of leg length and offset in minimally invasive THA. The use of pins fixed to the bone has a higher precision than pinless devices. This trial is registered with DRKS00000739.

Training the next generation of orthopaedic surgeons in total knee arthroplasty (TKA) is crucial, but might affect operative time and outcome. We hypothesized that the learning curve of residents in TKA has an impact on (1) operative time, (2) complication rates and (3) early postoperative outcome. In a retrospective analysis of 738 primary TKAs from our institutional joint registry, operative time, complication rates, patient-reported outcome measures (EQ-5D, WOMAC) within the first year and responder rates for positive outcome as defined by the OMERACT-OARSI criteria were compared between trainee and senior surgeons differentiating between conventional and navigated TKA. Mean operative time was 69.5±18.5min for trainees compared to 77.3±25.8min for senior surgeons (95%CI of the difference 1.5-13.9min, p = 0.02) in conventional TKA and 80.4±22.1min to 84.1±27.6min (95%CI of the difference -0.9-8.2min, p = 0.12) for navigated TKA, respectively. Intraoperative fracture (p≥0.36), thrombosis (p≥0.90), neurological deficits (p≥0.90) and infection rates (p≥0.28) were comparably low in both groups. Patient-reported outcome measures one year after TKA were similar for trainee and senior surgeons with EQ-5D 0.83±0.17 to 0.80±0.21 (p = 0.25) and WOMAC 74.85±18.60 to 72.77±20.12 (p = 0.44) for conventional TKA and EQ-5D 0.80±0.20 to 0.82±0.18 (p = 0.23) and WOMAC 72.71±18.52 to 75.77±17.78 (p = 0.07) for navigated TKA, respectively. Similarly, responder rates for positive outcome were comparable between trainees and senior surgeons (90.7% versus 87.0% p = 0.39 for conventional TKA, 88.7% versus 89.4% p = 0.80 for navigated TKA). Supervised TKA is a safe procedure during the learning curve of young orthopaedic surgeons., Competing Interests: TR has received research support by DePuy International, Otto Bock Foundation, Deutsche Arthose Hilfe outside this study. TR’s research group “patientindividual joint replacement” is supported by the German Ministry of Education and Research (BMBF, grant number 01EZ0915). JG got research support by MSD, Novartis, De Puy, Otto Bock Foundation outside this study. Further financial support was received for symposias from De Puy, Orthotech, Ozo-zours, Fischer Fussfit, Urban & Kemmler outside this study. There is no specific relation between the above mentioned commercial funders and the authors regarding employment, consultancy, patents or products. All financial support has been received outside this study. Therefore, this does not alter our adherence to PLOS ONE policies on sharing data and materials.

The scramble for available places to study medicine in Germany continues. One of the core points within the "Master Plan 2020", which has been recently adopted, is the reform of teaching concepts at German medical faculties. In the future, students of human medicine are to be trained primarily based upon competence-oriented, integrated curricula. The present paper is intended to present modern teaching concepts and methods, as well as current examination formats, which play a special role in student training in orthopaedics and traumatology. Knowledge in the field of medical and evidence-based treatment strategies, clinical examination techniques, diagnostic/therapeutic procedures and hygienic working conditions are especially important. Individual courses with a focus on research-, practice- and competence-orientation are intended to help the students grasp the depth of the subject.

Purpose: Our aim was to compare the long-term outcome between navigated and conventional total knee arthroplasty (TKA), which is currently not known., Methods: Long-term survivorship, clinical scores and radiographic results of a matched-pair group of 350 patients (350 knees) treated with navigated (n = 157) or conventional (n = 188) TKA for osteoarthritis over a period of 11 years were reviewed retrospectively., Results: The mean clinical follow-up was ten years. There were no clinically relevant differences with respect to any clinical outcome, patient satisfaction or pain between the two groups. Coronal leg alignment was closer (1.7-3.1°) to the neutral mechanical axis in the navigated group compared with the conventional group (2.6-4.7°). A total of 12 knees (6.4%) in the conventional group and three (1.9%) in the navigated group underwent revision surgery (p = 0.04), resulting in an absolute risk reduction of 4.5% for revision surgery by using navigation. Using any revision as an end point, the ten-year Kaplan-Meier survivorship was 98.1% in the navigated and 92.5% in the conventional group., Conclusions: Navigated TKA improves implant survivorship compared with conventional TKA.

Purpose  Accurate assessment of cup orientation on postoperative pelvic radiographs is essential for evaluating outcome after THA. Here, we present a novel method for correcting measurement inaccuracies due to pelvic tilt and rotation. Method  In an experimental setting, a cup was implanted into a dummy pelvis, and its final position was verified via CT. To show the effect of pelvic tilt and rotation on cup position, the dummy was fixed to a rack to achieve a tilt between + 15° anterior and -15° posterior and 0° to 20° rotation to the contralateral side. According to Murray's definitions of anteversion and inclination, we created a novel corrective procedure to measure cup position in the pelvic reference frame (anterior pelvic plane) to compensate measurement errors due to pelvic tilt and rotation. Results  The cup anteversion measured on CT was 23.3°; on AP pelvic radiographs, however, variations in pelvic tilt (± 15°) resulted in anteversion angles between 11.0° and 36.2° (mean error 8.3°± 3.9°). The cup inclination was 34.1° on CT and ranged between 31.0° and 38.7° (m. e. 2.3°± 1.5°) on radiographs. Pelvic rotation between 0° and 20° showed high variation in radiographic anteversion (21.2°-31.2°, m. e. 6.0°± 3.1°) and inclination (34.1°-27.2°, m. e. 3.4°± 2.5°). Our novel correction algorithm for pelvic tilt reduced the mean error in anteversion measurements to 0.6°± 0.2° and in inclination measurements to 0.7° (SD± 0.2). Similarly, the mean error due to pelvic rotation was reduced to 0.4°± 0.4° for anteversion and to 1.3°± 0.8 for inclination. Conclusion  Pelvic tilt and pelvic rotation may lead to misinterpretation of cup position on anteroposterior pelvic radiographs. Mathematical correction concepts have the potential to significantly reduce these errors, and could be implemented in future radiological software tools. Key Points   · Pelvic tilt and rotation influence cup orientation after THA. · Cup anteversion and inclination should be referenced to the pelvis. · Radiological measurement errors of cup position may be reduced by mathematical concepts. Citation Format · Schwarz TJ, Weber M, Dornia C et al. Correction of Pelvic Tilt and Pelvic Rotation in Cup Measurement after THA - An Experimental Study. Fortschr Röntgenstr 2017; 189: 864 - 873., Competing Interests: Conflict of Interest: The authors declare that they have no conflict of interest.This article does not contain any studies with human participants or animals.This article does not contain any patient data., (© Georg Thieme Verlag KG Stuttgart · New York.)

Background The estimation of femoral version in preoperative planning of total hip arthroplasty and to assess complications after total hip arthroplasty is crucial. Recent studies have recommended the posterior lesser trochanter line as an intraoperative reference for estimating femoral version. We hypothesized, that if there is a correlation, the posterior lesser trochanter line could be used to assess femoral version in computed tomography (CT) scans. Purpose To evaluate the correlation between the posterior lesser trochanter line and the posterior femoral condyle axis. Material and Methods CT scans of 126 patients after unilateral total hip arthroplasty were analyzed by means of a newly developed digital planning software for CT scans. Both hips were measured, the angle between the posterior lesser trochanter line and the posterior femoral condyle axis was determined, and the relationship between both lines was evaluated. Results We found significant differences between male and female patients ( P < 0.001) and between left and right femora ( P = 0.001). There was no significant difference between healthy hips and hips with osteoarthritis after total hip arthroplasty ( P = 0.901). Conclusion There is no reliable correlation between posterior lesser trochanter line and posterior femoral condyle axis. Therefore, posterior lesser trochanter line should not be used to assess femoral version in CT scans. As a consequence, the gold standard for measuring femoral version should still be a three-dimensional CT scan of the whole femur.

Cervical radiculopathy has become an increasing problem worldwide. Conservative treatment options have been recommended in many reviews on cervical radiculopathy, ranging from different types of physiotherapy to waiting for remission by natural history. No multimodal pain management concept (MPM) on an inpatient basis has been evaluated. This study aimed at showing the positive short-term effects of an inpatient multimodal pain management concept with focus on cervical translaminar epidural steroid injection for patients with cervical radiculopathy. 54 patients who had undergone inpatient MPM for 10 days were evaluated before and after 10-days treatment. The NRS (0-10) value for arm pain could be reduced from 6.0 (IQR 5.7-6.8) to 2.25 (IQR 2.0-3.1) and from 5.9 (IQR 4.8-6.0) to 2.0 (IQR 1.7-2.6) for neck pain. Neck pain was reduced by 57.4% and arm pain by 62.5%. 2 days after epidural steroid injection, pain was reduced by 40.1% in the neck and by 43.4% in the arms. MPM seems to be an efficient short-term approach to treating cervical radiculopathy. Cervical translaminar epidural steroid injection is an important part of this concept. In the absence of a clear indication for surgery, MPM represents a treatment option.

Impingement is a major source of dislocation and aseptic loosening in total hip arthroplasty (THA). We compared impingement free range of motion (ROM) using a novel computer navigated femur first approach to conventional THA. In addition, impingement between genders was also explored. In a retrospective analysis of 121 THA patients, subject-specific post-operative ROM was simulated using post-operative 3D-CT data, and compared with the benchmark ROM, essential for activities of daily living. Three parameters were defined to express both implant-to-implant (ITI) and bone-to-bone (BTB) impingement - coverage percentage, third angle, and impingement severity. Although coverage percentage was similar between the navigated and conventional group for both ITI (p = 0.69) and BTB (p = 0.82) impingement, third angle was significantly reduced in the navigation group for both ITI (p = 0.02) and BTB (p = 0.05) impingement. Impingement severity for both ITI (p = 0.01) and BTB (p = 0.05) was significantly decreased in the navigation group compared to the conventional. Impingement severity in men was considerably higher compared to women for both ITI (p = 0.002) and BTB (p = 0.02). Navigation guided femur first THA is able to improve alignment of ROM axis, and consequently, to reduce impingement in THA. Men seem to be more prone to impingement than women.

Training of young surgeons in total hip arthroplasty (THA) is crucial, but might affect operative time and outcome especially in minimally invasive (MIS) THA. We asked whether the learning curve of orthopaedic residents trained on MIS THA has an impact on (1) operative time (2) complication rates and (3) early postoperative outcome. In a retrospective analysis of over 1000 MIS THAs from our institutional joint registry, operative time, complication rates, patient reported outcome measures (Western Ontario and McMaster Universities Arthritis Index [WOMAC] and Euro-Qol 5D-5L [EQ-5D]) within the first year and responder rates for positive outcome as defined by the Outcome Measures in Rheumatology and Osteoarthritis Research Society International consensus responder (OMERACT-OARSI) criteria were compared between trainee and senior surgeons. Mean operative time was nine minutes longer for trainees compared to senior surgeons (78.1 ± 25.4 min versus 69.3 ± 23.8 min, p < 0.001). Dislocation (p = 0.21), intraoperative fracture (p = 0.84) and infection rates (p = 0.58) were comparably low in both groups. Both trainee and senior THAs showed excellent improvement of EQ-5D (0.34 ± 0.26 versus 0.32 ± 0.23, p = 0.40) and WOMAC (45.9 ± 22.1 versus 44.9 ± 20.0, p = 0.51) within the first year after surgery without clinical relevant differences. Similarly, responder rates for positive outcome were comparable between trainees with 92.9% and senior surgeons with 95.2% (p = 0.17). MIS THA seems to be a safe procedure during the learning curve of young orthopaedic specialists, but requires higher operative time.

Purpose: Accurate assessment of cup orientation on postoperative radiographs is essential for evaluating outcome after THA. However, accuracy is impeded by the deviation of the central X-ray beam in relation to the cup and the impossibility of measuring retroversion on standard pelvic radiographs., Method: In an experimental trial, we built an artificial cup holder enabling the setting of different angles of anatomical anteversion and inclination. Twelve different cup orientations were investigated by three examiners. After comparing the two methods for radiographic measurement of the cup position developed by Lewinnek and Widmer, we showed how to differentiate between anteversion and retroversion in each cup position by using a second plane. To show the effect of the central beam offset on the cup, we X-rayed a defined cup position using a multidirectional central beam offset. According to Murray's definition of anteversion and inclination, we created a novel corrective procedure to balance measurement errors caused by deviation of the central beam., Results: Measurement of the 12 different cup positions with the Lewinnek's method yielded a mean deviation of [Formula: see text] (95 % CI 1.3-2.3) from the original cup anteversion. The respective deviation with the Widmer/Liaw's method was [Formula: see text] (95 % CI 2.4-4.0). In each case, retroversion could be differentiated from anteversion with a second radiograph. Because of the multidirectional central beam offset ([Formula: see text] cm) from the acetabular cup in the cup holder ([Formula: see text] anteversion and [Formula: see text] inclination), the mean absolute difference for anteversion was [Formula: see text] (range [Formula: see text] to [Formula: see text] and [Formula: see text] (range [Formula: see text] to [Formula: see text] for inclination. The application of our novel mathematical correction of the central beam offset reduced deviation to a mean difference of [Formula: see text] for anteversion and [Formula: see text] for inclination., Conclusion: This novel calculation for central beam offset correction enables highly accurate measurement of the cup position.

Purpose: Various methods are available for measuring acetabular cup position after total hip arthroplasty (THA) on standard anterior-posterior (AP) radiographs. We compared the accuracy of a commercial radiographic planning software program with that of three-dimensional computed tomography (3D-CT) scans., Methods: We obtained plain AP radiographs and 3D-CTs from 65 patients after THA. In addition to calculating cup anteversion and inclination with 3D-CT, we determined the cup position using the radiographic planning software program mediCAD® 2.5 (Hectec, Niederviehbach, Germany). Furthermore, we compared the measurements using the inter-teardrop and bi-ischial lines as pelvic landmarks., Results: The mean difference in anteversion between 3D-CT and mediCAD® software was 0.1° using the inter-teardrop line (standard deviation [SD], 8.8°; range, -21° to 23°; p = 0.97) and 0.4° using the bi-ischial line (SD, 8.8°; range, -23° to 21°; p = 0.72). Inclination showed a mean difference of 0.6° using the inter-teardrop line (SD, 4.4°; range, -9° to 21°; p = 0.24) and 0.5° using bi-ischial line (SD, 4.6°; range, -9° to 22°; p = 0.35). The means for absolute differences were 7.2° for anteversion and 3.1° for inclination. With regard to using the bi-ischial or inter-teardrop line, no significant difference was found between the two pelvic landmarks. The intra-class correlation coefficient (ICC) was analysed for anteversion and inclination using either the inter-teardrop line or the bi-ischial line as radiographic baseline., Conclusions: A radiographic planning software program (mediCAD®) is a helpful tool for measuring cup inclination on AP radiographs. With respect to anteversion, measurements are rather susceptible to mistakes with mean inaccuracies of over 7°. Thus, 3D-CT remains the "gold standard" if a lower tolerance limit (±3°) is required for more complex biomechanical evaluations. As a pelvic landmark, the interteardrop line is preferential to the bi-ischial line because of its lower impact on the position of the pelvis.

Background: Multimodal pain management (MPM) represents a central approach to avoiding surgery in patients with lumbar radiculopathy. Independent of the type of health system, cost effectiveness and socioeconomic factors are becoming increasingly important. This study investigated the medium-term influence of conservative MPM on health care utilization and socioeconomic factors., Methods: This study compared subjective, objective, and socioeconomic factors of 60 patients after inpatient MPM because of lumbar radiculopathy, before and 1 year ± 2 weeks after treatment., Results: Over the course of the 1-year follow-up, one-third of the patients had not required any conservative treatment in comparison to 100% of patients before MPM therapy. The number of patients requiring analgesics could be significantly reduced from 26 to 12, and the number of patients who did not require any analgesics had increased from 14 to 32. After 1 year, the number of patients who had to regularly contact a physician because of low back pain (once per month for 6 months) had been reduced from 58 to 27., Conclusion: MPM is an effective approach to treating lumbar radiculopathy and reducing its negative influence on socioeconomic factors. Therapeutic benefits also include a decrease in health care utilization. Therefore, health care providers should place the mid-term success for patients and socioeconomic factors before the short-term costs of therapy., Competing Interests: Disclosure The authors report no competing financial interests or conflicts of interest in this work.

Purpose: Impingement is a major source for decreased range of motion (ROM) and dislocation in total hip arthroplasty (THA). In the current study we analyzed the impact of soft tissue impingement on ROM compared to bony and/or prosthetic impingement., Methods: In the course of a prospective clinical trial 54 patients underwent cementless total hip arthroplasty in the lateral decubitus position using imageless navigation. The navigation device enabled intra-operative ROM measurements indicating soft tissue impingement. Post-operatively, all patients received postoperative 3D-CT. Absolute ROM without bony and/or prosthetic impingement was calculated with the help of a collision-detection-algorithm., Results: Due to soft tissue impingement we found a reduced ROM of over 20° (p < 0.001) compared to bony and/or prosthetic impingement regarding flexion, extension, abduction and adduction and of over 10° regarding external rotation (p < 0.001). In contrast, soft tissue impingement showed less impact on internal rotation in 90° of flexion (p = 0.76). Multivariate analysis showed an association between BMI and flexion, whereas all other ROM directions were independent of BMI., Conclusions: Soft tissue has a major impact on impingement-free ROM after THA. For the majority of movements, soft tissue restrictions are more important than bony and prosthetic impingement. Future models of patient individual joint replacement including pre-operative (CT) planning and intra-operative navigation should include algorithms additionally accounting for soft tissue impingement.