Surgical management and outcomes following atypical subtrochanteric femoral fractures - results from a matched-pair analysis of the registry for geriatric trauma of the German Trauma Society

BACKGROUND AND OBJECTIVES

The outcomes of patients with atypical subtrochanteric fractures (ASFs) remain unclear. Data from a large international geriatric trauma registry were analysed to examine the outcome of patients with ASFs compared to patients with typical osteoporotic subtrochanteric fractures (TSFs).

MATERIALS AND METHODS

Data from the Registry for Geriatric Trauma of the German Trauma Society (Deutsche Gesellschaft für Unfallchirurgie [DGU]) (ATR-DGU) were analysed. All patients treated surgically for ASFs or TSFs were included in this analysis. Across both fracture types, a paired matching approach was conducted, where statistical twins were formed based on background characteristics sex, age, American Society of Anesthesiologists (ASA) score and walking ability. In-house mortality and mortality rates at the 120-day follow-up, as well as mobility at 7 and 120 days, the reoperation rate, hospital discharge management, the hospital readmission rate at the 120-day follow-up, health-related quality of life, type of surgical treatment and anti-osteoporotic therapy at 7 and 120 days, were assessed as outcome measures using a multivariate logistic regression analysis.

RESULTS

Amongst the 1,800 included patients, 1,781 had TSFs and 19 had ASFs. Logistic regression analysis revealed that patients with ASFs were more often treated with closed intramedullary nailing (RR = 3.59, p < 0.001) and had a higher probability of vitamin D supplementation as osteoporosis therapy at 120 days (RR = 0.88, p < 0.002). Patients with ASFs were also more likely to live at home after surgery (RR = 1.43, p < 0.001), and they also tended to continue living at home more often than patients with TSFs (RR = 1.33, p < 0.001). Accordingly, patients with TSFs had a higher relative risk of losing their self-sufficient living status, as indicated by increased rates of patients living at home preoperatively and being discharged to nursing homes (RR = 0.19, p < 0.001) or other hospitals (RR = 0.00, p < 0.001) postoperatively.

CONCLUSIONS

Surgical treatment of ASFs was marked by more frequent use of closed intramedullary fracture reduction. Furthermore, patients with ASFs were more likely to be discharged home and died significantly less often in the given timeframe. The rate of perioperative complications, as indicated by nonsignificant reoperation rates, as well as patient walking abilities during the follow-up period, remained unaffected.

Influence of avascular necrosis of the femoral head on hip prosthesis integration: a radiological analysis

BACKGROUND

Avascular osteonecrosis of the femoral head (AVN) often results in total hip arthroplasty (THA). The cause for increased THA revision rates among patients with AVN is not yet fully understood.

PURPOSE

To perform a comparative radiological analysis of implant integration between patients with AVN and osteoarthritis (OA).

MATERIAL AND METHODS

After a matched pair analysis of 58 patients, 30 received THA due to OA, 28 due to AVN. X-ray images were evaluated after one week ("baseline") and on average 37.58 months postoperatively ("endline"). The prosthesis was grouped into 10 regions of interest (ROI): seven femoral and three acetabular. Incidence, width, and extent of "radiolucent lines" were measured within each zone.

RESULTS

Between baseline and endline, width and extent progressed more noticeably in all femoral and acetabular zones among patients with AVN. In femoral ROI 1, the width increased in 40% of AVN cases compared to 6.7% of OA cases. For acetabular ROI 3, the width increased in 26.7% of AVN cases compared to no perceived changes in the OA group. No signs of prosthetic loosening were found in the AVN group.

CONCLUSION

The increase of width and extent of radiolucent lines over time in patients with AVN could be a sign of lack of osteointegration. However, prosthetic loosening in absence of clinical symptoms cannot be deduced from radiological findings after medium-term postoperative follow-up. Further long-term studies are required to monitor how radiolucent lines develop in respect to long-term implant loosening. Dependent on bone quality, individually adapted reaming and broaching of the implant site are recommended.

Comparison of two joint-preserving treatments for osteonecrosis of the femoral head: core decompression and core decompression with additional cancellous bone grafting

OBJECTIVE

Femoral head necrosis (FHN) affects mostly young and active people. The most common operative therapy is core decompression (CD) with optional cancellous bone grafting (CBG). Because little information is available on the long-term results of these procedures, we investigated the effectiveness of CD and CD + CBG in patients with ARCO stage II FHN in terms of postoperative pain, range of motion, patient-reported outcome measures (Harris Hip Score, Hip Disability and Osteoarthritis Outcome Score, EuroQol 5D, and Short Form 36 Questionnaire), and disease progression.

METHODS

We retrospectively compared 11 patients treated with CD alone 48.0 months (range, 26.3-68.5 months) postoperatively versus 11 patients treated with CD + CBG 69.2 months (range, 38.0-92.9 months) postoperatively. All patients were assessed according to a routine clinical protocol involving a clinical examination, questionnaires, and radiological imaging (X-ray and magnetic resonance imaging).

RESULTS

The clinical and radiological results showed no significant differences between the two groups. Both interventions demonstrated equal results according to clinical scores.

CONCLUSIONS

Our data may encourage application of the less invasive technique of CD alone without CBG, which is more surgically demanding. Further prospective studies with longer follow-up are necessary to clarify the risk factors for therapy failure.

Minimally invasive treatment of tibial plateau depression fractures using balloon tibioplasty: Clinical outcome and absorption of bioabsorbable calcium phosphate cement

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.

Influence of Extracellular Vesicles Isolated From Osteoblasts of Patients With Cox-Arthrosis and/or Osteoporosis on Metabolism and Osteogenic Differentiation of BMSCs

Background: Studies with extracellular vesicles (EVs), including exosomes, isolated from mesenchymal stem cells (MSC) indicate benefits for the treatment of musculoskeletal pathologies as osteoarthritis (OA) and osteoporosis (OP). However, little is known about intercellular effects of EVs derived from pathologically altered cells that might influence the outcome by counteracting effects from “healthy” MSC derived EVs. We hypothesize, that EVs isolated from osteoblasts of patients with hip OA (coxarthrosis/CA), osteoporosis (OP), or a combination of both (CA/OP) might negatively affect metabolism and osteogenic differentiation of bone-marrow derived (B)MSCs.

Methods: Osteoblasts, isolated from bone explants of CA, OP, and CA/OP patients, were compared regarding growth, viability, and osteogenic differentiation capacity. Structural features of bone explants were analyzed via μCT. EVs were isolated from supernatant of naïve BMSCs and CA, OP, and CA/OP osteoblasts (osteogenic culture for 35 days). BMSC cultures were stimulated with EVs and subsequently, cell metabolism, osteogenic marker gene expression, and osteogenic differentiation were analyzed.

Results: Trabecular bone structure was different between the three groups with lowest number and highest separation in the CA/OP group. Viability and Alizarin red staining increased over culture time in CA/OP osteoblasts whereas growth of osteoblasts was comparable. Alizarin red staining was by trend higher in CA compared to OP osteoblasts after 35 days and ALP activity was higher after 28 and 35 days. Stimulation of BMSC cultures with CA, OP, and CA/OP EVs did not affect proliferation but increased caspase 3/7-activity compared to unstimulated BMSCs. BMSC viability was reduced after stimulation with CA and CA/OP EVs compared to unstimulated BMSCs or stimulation with OP EVs. ALP gene expression and activity were reduced in BMSCs after stimulation with CA, OP, and CA/OP EVs. Stimulation of BMSCs with CA EVs reduced Alizarin Red staining by trend.

Conclusion: Stimulation of BMSCs with EVs isolated from CA, OP, and CA/OP osteoblasts had mostly catabolic effects on cell metabolism and osteogenic differentiation irrespective of donor pathology and reflect the impact of tissue microenvironment on cell metabolism. These catabolic effects are important for understanding differences in effects of EVs on target tissues/cells when harnessing them as therapeutic drugs.

The effects of soft tissue lateral release on the stability of the ligament complex of the knee

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.

Weakening of the knee ligament complex due to sequential medial release in total knee arthroplasty

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.

The final implant position of a commonly used collarless straight tapered stem design (Corail®) does not correlate with femoral neck resection height in cement-free total hip arthroplasty: a retrospective computed tomography analysis

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.

Customized implants for acetabular Paprosky III defects may be positioned with high accuracy in revision hip arthroplasty

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.

Assessment of pelvic tilt in anteroposterior radiographs by means of tilt ratios

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.

Predictors of Outcome After Primary Total Joint Replacement

BACKGROUND

Total hip and knee replacements are frequently performed curative treatment options in end-stage arthritis. In this study, we analyzed clinical outcome, complications, and predictors of outcome in modern joint replacement.

METHODS

In a retrospective analysis of over 2000 primary total hip and knee replacements from our institutional joint registry, responder rates for positive outcome as defined by the OMERACT-OARSI criteria, postoperative complication rates, and patient-reported outcome measures (EQ-5D, WOMAC) within the first year were compared between hip and knee replacements. Furthermore, preoperative risk factors associated with nonresponder rate were evaluated.

RESULTS

Positive responder rate was higher for hip replacements with 92.8% (1145/1234) than for knee replacements with 86.1% (839/975, P < .001). Infection rates were lower (P = .04), whereas intraoperative fracture occurred more frequently (P = .001) in hip than in knee replacements. Patient-reported outcome measures 1 year after surgery were higher in hip than in knee replacements with EQ-5D (0.88 ± 0.17 to 0.81 ± 0.19, P < .001) and WOMAC (84.58 ± 16.73 to 74.31 ± 18.94, P < .001). Besides the type of joint replacement (hazard ratio [HR] 2.0, P < .001), high preoperative outcome measures (HR 7.4, P < .001) and male gender (HR 1.4, P = .05) were independent risk factors of nonresponders after joint replacement.

CONCLUSION

Both total hip and knee replacements are safe procedures with low complication rates. Still, postoperative outcome is higher in hip than in knee arthroplasty. High preoperative clinical scores are a risk factor for poor clinical improvement following total joint replacement and can be used in counseling patients in the office.

What is the optimal valgus pre-set for intramedullary femoral alignment rods in total knee arthroplasty?

PURPOSE

In total knee arthroplasty (TKA), intramedullary guides are often used for aligning the distal femoral cutting block. Because of the highly varying angles between the mechanical axis and the anatomical femoral axis (AMA), different valgus pre-sets have been recommended. The present study investigated the optimal valgus pre-set (measuring the AMA in long-leg radiographs or at 5°, 6°, 7° or 8° valgus) to align the cutting block perpendicularly to the mechanical axis.

METHODS

The AMA was preoperatively measured in weight-bearing long-leg radiographs. After alignment of the cutting block by means of an intramedullary rod, deviation of the block from the mechanical femoral axis was measured with a pinless navigation device. The true AMA (tAMA) was calculated by adding the valgus pre-set of the alignment rod to the deviation measured with the navigation device. Mean deviations between the tAMA and (a) the AMA measured by the surgeon, (b) the AMA calculated with the computer software, (c) 5°, (d) 6°, (e) 7° and (f) 8° valgus pre-sets were measured for each patient. The lowest mean differences were determined.

RESULTS

The 40 knees measured showed a mean tAMA of 7.2° valgus (1.7 SD) (range 4°-11.5°). The following mean differences and 95 % limits of agreement were calculated: 2.2 (-1.2, 5.5) to the tAMA for the 5° valgus pre-set, 1.2 (-2.2, 4.5) for 6°, 0.2 (-3.2, 3.5) for 7° and -0.8 (-4.2, 2.5) for 8°. AMA measurements by the surgeon and with the digital medical planning software yielded mean differences of 0.6 (-3.1, 4.3) and 0.4 (-4.1, 4.8), respectively.

CONCLUSION

In the present setting, the best mean distal femoral cutting block alignment perpendicular to the mechanical femoral axis could be achieved with a valgus pre-set of 7° and not by measuring the AMA. Nevertheless, we recommend conducting weight-bearing radiographs of the entire leg prior to TKA for easy detection of any anatomical varieties, old fractures, long stems of total hip arthroplasties or cement. However, surgeons must be aware that exact coronal component alignment can only be achieved by navigational devices.

LEVEL OF EVIDENCE

Diagnostic study, Level II.

Posterior lesser trochanter line should not be used as reference for assessing femoral version in CT scans: a retrospective reliability and agreement study

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.

[Total knee arthroplasty in the elderly]

BACKGROUND

The number of total knee arthroplasties in elderly patients is increasing in accordance with the demographic shift in the population.

OBJECTIVE

Analysis of the special situation in the elderly, conservative treatment options, perioperative risk factors, preoperative preparation, special intraoperative features and outcome.

METHODS

Analysis of currently available scientific data and presentation of own scientific study results.

RESULTS

Total knee arthroplasty in elderly patients is related to an increased perioperative risk of complications. A thorough interdisciplinary preparation is required to reduce risk factors. Ligament stability of the knee does not correlate with age. The postoperative outcome after total knee arthroplasty in elderly patients is decisively influenced by the preoperative function and psychosocial parameters.

CONCLUSION

Total knee arthroplasty in elderly patients is particularly challenging for orthopedic surgeons and requires close interdisciplinary cooperation.

Correction of Pelvic Tilt and Pelvic Rotation in Cup Measurement after THA - An Experimental Study

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.

Stability of knee ligament complex of Thiel-embalmed cadaver compared to in vivo knee

BACKGROUND

The first biomechanical evaluation of new implants is usually carried out with cadavers. Fixation of Thiel-embalmed cadavers is supposed to preserve the histological structure, colour and consistency of the tissue and has a low risk of infection and toxicity. However, the biomechanical properties of Thiel-fixated tissue are still unknown. The aim of this study was to quantify the effect of the Thiel-embalming method on the elastic properties of the ligament complex of the knee compared to in vivo knees during total knee arthroplasty.

METHODS

The results of biomechanical tensile tests with 10 Thiel-embalmed knees were compared with the findings of 10 patients who underwent total knee arthroplasty with a standardised knee balancer at our department. We reconstructed the force-elongation curves of the medial and lateral ligament complex and calculated the stiffness in direct correlation with overall soft tissue stability in full extension and in 90° of flexion.

RESULTS

All curves consisted of a non-linear part at the beginning and a linear part from about 80N onwards. In full extension, median stiffness in the cadavers was 26.6N/mm for the medial compartment and 31.6N/mm for the lateral compartment. The values for in vivo were 25.7N/mm for the medial compartment and 25.3N/mm for the lateral compartment (p=0.684 for the medial compartment and p=0.247 for the lateral compartment). In 90° of flexion, median stiffness in the cadaver group was 24.7N/mm for the medial compartment and 22.2N/mm for the lateral compartment. In vivo, median stiffness was 30.3N/mm for the medial compartment and 29.2N/mm for the lateral compartment (p=0.009 for the medial compartment and p=0.143 for the lateral compartment).

CONCLUSION

Stiffness of the medial and lateral ligament complex in the knee was comparable between Thiel-embalmed cadavers and in vivo patients during total knee arthroplasty. Thiel fixation seems to preserve the soft tissue properties similar to those in vivo.

Central X-ray beam correction of radiographic acetabular cup measurement after THA: an experimental study

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.

Native femoral anteversion should not be used as reference in cementless total hip arthroplasty with a straight, tapered stem: a retrospective clinical study

Backround

Improper femoral and acetabular component positioning can be associated with instability, impingement, component wear and finally patient dissatisfaction in total hip arthroplasty (THA). The concept of “femur first”/“combined anteversion”, incorporates various aspects of performing a functional optimization of the prosthetic stem and cup position of the stem relative to the cup intraoperatively.

In the present study we asked two questions: (1) Do native femoral anteversion and anteversion of the implant correlate? (2) Do anteversion of the final broach and implant anteversion correlate?

Methods

In a secondary analysis of a prospective controlled trial, a subgroup of 55 patients, who underwent computer-assisted, cementless THA with a straight, tapered stem through an anterolateral, minimally invasive (MIS) approach in a lateral decubitus position were examined retrospectivly. Intraoperative fluoroscopy was used to verify a “best-fit” position of the final broach. An image-free navigation system was used for measurement of the native femoral version, version of the final broach and the final implant. Femoral neck resection height was measured in postoperative CT-scans. 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

The mean difference between native femoral version and final implant was 1.9° (+/− 9.5), with a range from −20.7° to 21.5° and a Spearman’s correlation coefficient of 0.39 (p < 0.003). In contrast, we observed a mean difference between final broach and implant version of −1.9° (+/− 3.5), with a range from −12.7° to 8.7° and a Spearman’s correlation coefficient of 0.89 (p < 0.001). In 83.6 % (46/55) final stem version was outside the normal range as defined by Tönnis (15-20°). The mean femoral neck resection height was 7.3 mm (+/− 5.6). There was no correlation between resection height and version of the implant (Spearman’s correlation coefficient 0.14).

Conclusion

Native femoral version significantly differs from the final anteversion of a cementless, straight, tapered stem and therefore is not a reliable reference in cementless THA. Measuring anteversion of the final “fit and fill” broach is a feasible assistance in order to predict final stem anteversion intraoperatively. There is no correlation between femoral neck resection height and version of the implant.

Visual intraoperative estimation of range of motion is misleading in minimally invasive total hip arthroplasty

INTRODUCTION

Generally range of motion (ROM) in total hip arthroplasty (THA) is intraoperatively assessed by eye. Can we assume that visual estimation of ROM is reliable?

METHODS

60 patients underwent cementless THA in a subgroup analysis of a clinical prospective trial using a minimally invasive anterolateral approach in lateral decubitus position. Four experienced surgeons intraoperatively estimated ROM visually by assessment of the femur relative to the alignment of the patient's pelvis. These estimations were compared with computer navigation measurements.

RESULTS

We found a mean difference between navigation measurements and intraoperative estimations by eye of -5.6° (±10.9°; -17° to 30°) for flexion, respectively, -0.4° (±10.7°; -24° to 30°) for extension, 8.7° (±9.0°; -10° to 34°) for abduction, 5.9° (±18.3°; -58° to 68°) for external rotation and -5.8° (±12.1°; -38° to 22°) for internal rotation. Multivariate analysis showed no association between the visual accuracy of estimation of ROM and patient characteristics, such as BMI, sex, grade of osteoarthritis and treatment side except for a significant correlation of visual accuracy of estimation of extension and the level of professional experience. Otherwise, the level of professional experience had no impact on the accuracy of estimation of ROM by eye.

CONCLUSIONS

Even the experienced surgeon's intraoperative estimation of ROM by eye is not reliable and differs up to 30° compared to objective measurements in minimally invasive THA. For accurate intraoperative assessment of ROM, the use of technical devices is recommended.

TRIAL REGISTRATION

DRKS00000739.

[Patella navigation in computer-assisted TKA : Intraoperative measurement of patellar kinematics. Video article]

INTRODUCTION

Patellofemoral maltracking is a relevant problem after total knee arthroplasty (TKA). Patella navigation is a tool that allows real time monitoring of patella tracking.

MATERIAL

This video contribution demonstrates the technique of patellofemoral navigation and a possible consequence of intraoperative monitoring. A higher postoperative lateral tilt is addressed with a widening of the lateral retinaculum in a particular manner.

CONCLUSION

In selected cases of patellofemoral problems, patella navigation is a helpful tool to evaluate patellofemoral tracking intraoperatively. Modifications of implant position and soft tissue measurements can then prevent postoperative patellofemoral maltracking.

Visual intraoperative estimation of cup and stem position is not reliable in minimally invasive hip arthroplasty

Background and purpose - In hip arthroplasty, acetabular inclination and anteversion-and also femoral stem torsion-are generally assessed by eye intraoperatively. We assessed whether visual estimation of cup and stem position is reliable. Patients and methods - In the course of a subgroup analysis of a prospective clinical trial, 65 patients underwent cementless hip arthroplasty using a minimally invasive anterolateral approach in lateral decubitus position. Altogether, 4 experienced surgeons assessed cup position intraoperatively according to the operative definition by Murray in the anterior pelvic plane and stem torsion in relation to the femoral condylar plane. Inclination, anteversion, and stem torsion were measured blind postoperatively on 3D-CT and compared to intraoperative results. Results - The mean difference between the 3D-CT results and intraoperative estimations by eye was -4.9° (-18 to 8.7) for inclination, 9.7° (-16 to 41) for anteversion, and -7.3° (-34 to 15) for stem torsion. We found an overestimation of > 5° for cup inclination in 32 hips, an overestimation of > 5° for stem torsion in 40 hips, and an underestimation < 5° for cup anteversion in 42 hips. The level of professional experience and patient characteristics had no clinically relevant effect on the accuracy of estimation by eye. Altogether, 46 stems were located outside the native norm of 10-20° as defined by Tönnis, measured on 3D-CT. Interpretation - Even an experienced surgeon's intraoperative estimation of cup and stem position by eye is not reliable compared to 3D-CT in minimally invasive THA. The use of mechanical insertion jigs, intraoperative fluoroscopy, or imageless navigation is recommended for correct implant insertion.

Decreased femoral periprosthetic bone mineral density: a comparative study using DXA in patients after cementless total hip arthroplasty with osteonecrosis of the femoral head versus primary osteoarthritis

INTRODUCTION

Trabecular properties in osteonecrosis of the femoral head (ONFH) are altered for bone volume and structure in the femoral head and proximal femoral canal. We analysed the periprosthetic bone mineral density (BMD) as a correlate to bony ingrowth in patients with ONFH who received a cementless THA.

MATERIALS AND METHODS

We performed a matched-pair analysis of 100 patients with ONFH (n = 50) and primary osteoarthritis (n = 50) who received the same, unilateral cementless THA. We compared the periprosthetic BMD 5 years after surgery by means of dual energy X-ray absorptiometry (DXA) analysing the seven femoral regions of interest (ROIs) according to Gruen.

RESULTS

Within the ONFH group, significantly lower BMD values were found in the ROI 1 and 7 (p < 0.05). No statistically significant difference was found for ROIs 2-6.

CONCLUSIONS

An altered periprosthetic bone stock in the proximal femur in patients with prior ONFH might be a possible risk factor for premature loosening of the femoral stem in THA. Surgeons need to consider coating and fixation philosophy of cementless implants when choosing the right stem for patients with ONFH.

Measuring Acetabular Cup Orientation on Antero-Posterior Radiographs of the Hip after Total Hip Arthroplasty with a Vector Arithmetic Radiological Method. Is It Valid and Verified for Daily Clinical Practice?

PURPOSE

The aim of this prospective study is to validate a vector arithmetic method for measuring acetabular cup orientation after total hip arthroplasty (THA) and to verify the clinical practice.

MATERIALS AND METHODS

We measured cup anteversion and inclination of 123 patients after cementless primary THA twice by two examiners on AP pelvic radiographs with a vector arithmetic method and compared with a 3D-CT based reconstruction model within the same radiographic coronal plane.

RESULTS

The mean difference between the radiographic and the 3D-CT measurements was - 1.4° ± 3.9° for inclination and 0.8°± 7.9° for anteversion with excellent correlation for inclination (r = 0.81, p < 0.001) and moderate correlation for anteversion (r = 0.65, p < 0.001). The intraclass correlation coefficient for measurements on radiographs ranged from 0.98 (95 %-CI: 0.98; 0.99) for the first observer to 0.94 (95 %-CI: 0.92; 0.96) for the second observer. The interrater reliability was 0.96 (95 %-CI: 0.93; 0.98) for inclination and 0.93 (95 %-CI: 0.85; 0.96) for anteversion.

CONCLUSION

The largest errors in measurements were associated with an extraordinary pelvic tilt. In order to get a valuable measurement for measuring cup position after THA on pelvic radiographs by this vector arithmetic method, there is a need for a correct postoperative ap view, with special regards to the pelvic tilt for the future.

KEY POINTS

• Measuring acetabular cup orientation on anteroposterior radiographs of the hip after THA is a helpful procedure in everyday clinical practice as a first-line imaging modality• CT remains the golden standard to accurately determine acetabular cup position.• Future measuring on radiographs for cup orientation after THA should account for integration of the pelvic tilt in order to maximize the measurement accuracy. Citation Format: • Craiovan B, Weber M, Worlicek M et al. Measuring Acetabular Cup Orientation on Antero-Posterior Radiographs of the Hip after Total Hip Arthroplasty with a Vector Arithmetic Radiological Method. Is It Valid and Verified for Daily Clinical Practice?. Fortschr Röntgenstr 2016; 188: 574 - 581.

Comparative clinical study of the prophylaxis of heterotopic ossifications after total hip arthroplasty using etoricoxib or diclofenac

PURPOSE

This study investigated whether etoricoxib (COX-II blocker) has a superior efficacy of preventing heterotopic ossification (HO) after total hip arthroplasty (THA) compared to diclofenac (non-selective NSAID).

METHODS

One hundred patients were included (50 in each group) in this single centre, prospective, double-blinded, randomized, controlled trial. Etoricoxib (90 mg) was administered once and diclofenac (75 mg) twice per day for a perioperative period of nine days. The incidence of HO was evaluated on radiographs of the pelvis six months after surgery.

RESULTS

Eighty nine of 100 (89 %) patients could be analysed. The overall HO incidence was 37.8 %. There was no significant difference between both study groups. Twelve patients (27.3 %) of the DIC group and 13 patients (28.9 %) of the ETO group showed Brooker grade I ossifications. Five patients (11.4 %) of the DIC and four patients of the ETO (8.9 %) group showed grade II HO formations. No class III or IV HO formations occured in both groups. Ad hoc analysis detected a negative correlation between HO incidence and limited abduction and internal rotation of the hip.

CONCLUSIONS

Etoricoxib and diclofenac are equally effective for oral HO prophylaxis after primary cementless THA when given for nine peri-operative days to ensure a full recovery and high patient satisfaction.

Perioperative blood loss and gastrointestinal tolerability of etoricoxib and diclofenac in total hip arthroplasty (ETO-DIC study): a single-center, prospective double-blinded randomized controlled trial

OBJECTIVE

Non-selective NSAIDs can cause serious gastrointestinal side-effects. Selective COX-2 blockers are a reasonable alternative for pain treatment. They do not seem to affect platelet function and consequently cause a lower perioperative blood loss than non-selective NSAIDs. This study compared etoricoxib and diclofenac during a perioperative (9 days) period after THA to investigate total blood loss and gastrointestinal tolerability. The hypothesis was that etoricoxib is superior to diclofenac.

METHODS

A total of 100 patients (50 in each group) were included in this trial. Etoricoxib (90 mg) was administered once and diclofenac sodium (75 mg) twice daily for 9 days. Total blood loss during and after primary cementless THA was detected. The rate of adverse events (AEs) and serious adverse events (SAEs) was analyzed to detect gastrointestinal tolerability.

RESULTS

The mean total blood loss (calculated) was 1548 ± SD 468 ml in the etoricoxib (ETO) group and 1649 (SD 547) ml in the diclofenac (DIC) group. The mean duration of THA was 81 min (SD 29) in the DIC and 75 min (SD 30) in the ETO group. Hence, the mean calculated total blood loss was 101 ml higher in the DIC group. This difference was not statistically significant (p = 0.334). Fifty-six patients (28 in each group) received a cell saver retransfusion, but only one patient (ETO group) needed an additional red blood cell transfusion. The hidden blood loss was 1067 ml (SD 603) in the DIC group and 999 ml (SD 378) in the ETO group. The gastrointestinal tolerability (number of adverse and serious adverse events) was not significantly different between groups.

CONCLUSION

There was no statistically significant difference in perioperative blood loss after primary THA under etoricoxib (90 mg) compared to diclofenac (75 mg). Furthermore, no gastrointestinal superiority of etoricoxib could be detected during a short period of 9 days.

[Operative treatment of the rheumatic shoulder]

The duration and severity of rheumatic diseases of the shoulder correlate with symptom frequency, structural changes and associated functional limitations. The multifactorial character of the underlying rheumatic disease requires a multimodal therapeutic concept including interaction of surgical and non-surgical disciplines. In addition to basic systemic anti-inflammatory medication, injections targeting the synovial tissue by corticoid instillation and glenohumeral radiosynoviorthesis (with an intact rotator cuff) are further options. Operative interventions on rheumatic shoulders can be characterized as disease-modifying, protective, reconstructive or palliative, depending on the stage. Combining minimally invasive arthroscopic surgical techniques with modern basic therapy has the potential to shift the indications for operative interventions towards an earlier stage of disease without favoring or propagating structural alterations which have already occurred. In cases of severe joint destruction with loss of the rotator cuff, reverse shoulder arthroplasty can be an appropriate option.

Difference in periprosthetic acetabular bone mineral density: Prior total hip arthroplasty: Osteonecrosis of the femoral head versus primary osteoarthritis

BACKGROUND

Total hip arthroplasty (THA) could be associated with a higher failure rate in patients after osteonecrosis of the femoral head (ONFH) compared to a patient population with primary osteoarthritis prior THA, especially regarding the acetabular component. One major reason could be the compromised acetabular bone quality. Therefore, we performed a retrospective case matched study to assess: 1) Is there a difference in periprosthetic bone mineral density between patients with an ONFH prior THA and controls? 2) Do patients with an ONFH prior THA have a lower bone mineral density compared to controls? 3) Which region in the periprosthetic bone stock is more likely to present differences in periprosthetic bone mineral density between both groups?

HYPOTHESIS

We hypothesized that there is a poorer bone mineral density (BMD) in the periacetabular bone stock in patients with an ONFH prior THA compared to controls receiving a THA due to primary osteoarthritis.

PATIENTS AND METHODS

We compared the BMD of 50 patients with ONFH to 50 controls with primary osteoarthritis prior THA using the same implant in mean 5 years after surgery by means of dual energy X-ray absorptiometry (DXA). We analysed 3 acetabular ROIs according to DeLee and Charnley in a modified measurement technique.

RESULTS

In ROI 3, representing acetabulum's upper aspect, statistically significant lower BMD values for the ONFH group could be found (P < 0.05). No difference was found for the modified ROIs 1 and 2 (respectively medial and lower acetabulum).

DISCUSSION

The results indicate a poorer periacetabular BMD in patients with ONFH prior THA, which might be responsible for premature loosening of the acetabular cup in THA. Due to a lack of literature, further clinical investigations are required to confirm our results.

LEVEL OF EVIDENCE

III: retrospective case-control study.

Current therapeutic strategies of heterotopic ossification--a survey amongst orthopaedic and trauma departments in Germany

Background

Heterotopic ossification (HO) is a complication after tissue trauma, fracture and surgery (i.e. total hip arthroplasty). Prophylaxis is the most effective therapy. If HO formations become symptomatic and limit patients’ quality of life, revision surgery is indicated and is usually combined with a perioperative oral prophylaxis (NSAIDs) and/or irradiation. However, a long-term use of NSAIDs can induce gastro-intestinal or cardiac side-effects and possible bony non-unions during fracture healing. Subject of this study was to assess the current status of HO prophylaxis after injuries or fractures and to evaluate current indications and strategies for excision of symptomatic HO.

Methods

Between 2013 and 2014, a questionnaire was sent to 119 orthopaedic and trauma surgery departments in Germany. Participation was voluntary and all acquired data was given anonymously.

Results

The cumulative feedback rate was 71 %. Trauma and orthopaedic surgery departments in Germany recommend oral HO prophylaxis after acetabulum and femoral neck fractures, elbow dislocation, and fracture or dislocation of the radial head. Pain upon movement and an increasing loss of range of motion in the affected joint are considered to be clear indications for HO surgery. A partial removal of ROM-limiting HO formations was also considered important. The vast majority of all departments include perioperative oral HO prophylaxis and/or irradiation if surgical HO removal is planned. The choice and duration of NSAIDs is highly variable.

Conclusion

HO is of clinical significance in current traumatology and orthopaedics. Certain fractures and injuries are prone to HO, and prophylactic measures should be taken. The respondents in this survey assessed current therapeutic strategies for HO formations similarly. These concepts are in line with the literature. However, the duration of perioperative oral HO prophylaxis varied greatly among the specialist centres. This is significant as a long-term use of NSAIDs fosters a potential risk for the patients’ safety and could influence the clinical outcome. National and international guidelines need to be developed to further reduce HO rates and improve patients’ safety in trauma and orthopaedic surgery.

[Clinical examination of the hip joint in adults]

Complaints in the region of the hips and pelvis are often difficult to classify. This is due to the fact that pain projection and overlapping can occur; therefore, the complete region of the lumbar spine, pelvis and hips must be considered as a single entity in which alterations can result in radiation throughout the whole region. There are many different anatomical structures within the pelvic region so that the function of various muscle components can be impaired and cause pathological alterations to positional relationships of bony structures or even alterations to other soft tissues, such as ligaments, tendons and labra. In terms of differential diagnostics the groin must be seen as the weak point of the peritoneum and vascular system and taken into consideration. Therefore, a detailed and targeted medical history, functional testing and specific examinations and tests are necessary to narrow down the pathology in question and reach a definitive diagnosis. Orthopedic surgeons must know which conspicuous features can lead to which problems and which anatomical structures are likely to be affected by irritation. The results of the clinical examination are the basis for targeted imaging diagnostics and subsequent therapy.

[Clinical examination of the hip joint in adults]

Complaints in the region of the hips and pelvis are often difficult to classify. This is due to the fact that pain projection and overlapping can occur; therefore, the complete region of the lumbar spine, pelvis and hips must be considered as a single entity in which alterations can result in radiation throughout the whole region. There are many different anatomical structures within the pelvic region so that the function of various muscle components can be impaired and cause pathological alterations to positional relationships of bony structures or even alterations to other soft tissues, such as ligaments, tendons and labra. In terms of differential diagnostics the groin must be seen as the weak point of the peritoneum and vascular system and taken into consideration. Therefore, a detailed and targeted medical history, functional testing and specific examinations and tests are necessary to narrow down the pathology in question and reach a definitive diagnosis. Orthopedic surgeons must know which conspicuous features can lead to which problems and which anatomical structures are likely to be affected by irritation. The results of the clinical examination are the basis for targeted imaging diagnostics and subsequent therapy.

No difference between standard and high flexion cruciate retaining total knee arthroplasty: a prospective randomised controlled study

PURPOSE

The purpose of this prospective, randomised, double-blind study was to test the hypotheses that patients with high-flexion total knee arthroplasty (TKA) have (1) a wider/greater range of motion (ROM) post-operatively and (2) higher levels of knee society score (KSS) and WOMAC score post-operatively compared to standard TKA.

METHODS

In this study, 28 high flexion with 31 standard TKAs were compared. We measured ROM, pre-operatively, on day 3, 7, 28, and after 6 and 36 months post-operatively as well as KSS and WOMAC score pre-operatively, on day 28 and after 6 and 36 months post-operatively.

RESULTS

No statistically significant differences were found between both groups with regard to the target parameters. The mean ROM was 113° (range 80°-140°, SD 13.4°) in the control group (standard TKA) and 117° (range 90°-140°, SD 12.3) in the study group (high-flexion TKA) at 36 months follow-up [p = not significant (n.s.)]. The KSS pre-operatively was 38.2 (range 8-64, SD 15.8) in the control group and 45.9 (range 8-74, SD 16.0) in the study group (n.s.) increasing to 157.6 in the control group and 156.7 in the study group (p = n.s) at 36 months follow-up.

CONCLUSION

This study could not confirm significant benefits of high-flexion TKA compared to standard TKA with regard to ROM and higher levels of KSS and WOMAC score.

LEVEL OF EVIDENCE

I.

The impact of standard combined anteversion definitions on gait and clinical outcome within one year after total hip arthroplasty

PURPOSE

Different target areas within the concept of combined cup and stem anteversion have been published for total hip arthroplasty (THA). We asked whether component positioning according to eight standard combined anteversion rules is associated with (1) more physiological gait patterns, (2) higher improvement of gait variables and (3) better clinical outcome after THA.

METHODS

In a prospective clinical study, 60 patients received cementless THA through an anterolateral MIS approach in a lateral decubitus position. Six weeks postoperatively, implant position was analysed using 3D-CT by an independent external institute. Preoperatively, six and 12 months postoperatively range of motion, normalized walking speed and hip flexion symmetry index were measured using 3D motion-capture gait analysis. Patient-related outcome measures (HHS, HOOS, EQ-5D) were obtained by an observer blinded to 3D-CT results. Eight combined anteversion definitions and Lewinnek's "safe zone" were evaluated regarding their impact on gait patterns and clinical outcome.

RESULTS

Combined cup and stem anteversion according to standard combined anteversion definitions as well as cup placement within Lewinnek's "safe zone" did not influence range of motion, normalized walking speed and/or hip flexion symmetry index six and 12 months after THA. Similarly, increase of gait parameters within the first year after THA was comparable between all eight combined anteversion rules. Clinical outcome measures like HHS, HOOS and EQ-5D did not show any benefit for either of the combined anteversion definitions.

CONCLUSIONS

Standard combined cup and stem anteversion rules do not improve postoperative outcome as measured by gait analysis and clinical scores within one year after THA.

Pinless navigation in total knee arthroplasty: navigation reduced by the maximum?

PURPOSE

Restoring a neutral mechanical axis in total knee arthroplasty (TKA) (within ±3° of varus/valgus) is associated with superior functional outcome and reduced early implant failure. Using conventional alignment jigs results in malalignment in >20 % of cases. In this study, we investigated the reduction of outliers within the threshold of ±3° of leg alignment using a "pinless" navigation system in comparison with conventional alignment jigs investigated.

METHODS

In this randomised prospective study, 80 patients were randomly assigned/allocated to the pinless or conventional control group. After surgery, the two groups were compared regarding outliers > ±3° by means of hip-knee-ankle angle (HKA), mechanical medial proximal tibia angle (mMPTA), mechanical lateral distal femoral angle (mLDFA) and duration of surgery. Student's unpaired t test was used for quantitative variables, Fisher's exact test compared groups (pinless vs. control) and a two-sided p value of ≤0.05 was considered statistically significant.

RESULTS

In the pinless group, outliers regarding HKA and mLDFA > ±3° was significantly reduced (p = 0.025 and p = 0.002 respectively). In the pinless group, the surgery duration was significantly longer (75.6 vs. 64.5 minutes, p < 0.001).

CONCLUSION

Pinless navigation is effective in reducing outliers > ±3° regarding HKA without risking pin-related complications, such as fractures, infections or breaking screws. However, not all tools for conventional navigation in TKA, such as real-time measurements of the tibiofemoral axis and gap balancing, are available.

[What medical students want - evaluation of medical recruitment ads by future physicians]

OBJECTIVE

Three-quarters of all hospitals in Germany are now struggling to fill open positions for doctors. The medical job ad is a vital tool for human resources marketing and an important image factor. The present study examines the importance of information and offers in medical recruitment ads on application decisions by medical students.

METHOD

A total of 184 future physicians from clinical semesters participated voluntarily in an anonymous cross-sectional survey. Using a standardised questionnaire, the importance of 49 -individual items extracted from medical recruitment ads were rated with the help of a 4-point Likert Scale. Finally, the study participants prioritised their reasons for an application as a physician.

RESULTS

Primary influence on the application decision on medical recruitment ads by medical students had offers/information in relation to education and training aspects and work-life balance. Payment rates for physicians and work load played an important role for the application motivation. Additional earnings for, e. g., emergency calls, providing of medical expertise and assistance with housing, relocation and reimbursement of interview expenses were less crucial. In prioritising key reasons for selecting a prospective employer "regular working hours," an "individual training concept" and an "attractive work-life balance" scored the highest priority. The "opportunity for scientific work" was assigned only a small significance.

CONCLUSION

High importance for the application decision by future physicians on medical recruitment ads is placed on jobs with an opportunity for personal development and aspects that contribute to work-life balance.

[Melorheostosis of the foot: a case report of a rare entity]

INTRODUCTION

Melorheostosis is a rare bony dysplasia and often recognised just sporadically by chance.

CASE REPORT

We present a case of a 15 year old girl who presented a melorheostosis of the left foot. After birth there was recognized a shortening and deformity of the 2nd toe on the left foot. Furthermore she had an interphalangeal hallux valgus that displaced the 2nd toe increasingly. Thus in the last years there were more and more difficulties to wear normal shoes. Conservative therapy was not successful. We performed a lengthening extending osteotomy of the 2nd toe (a modified Weil osteotomy) and an Akin osteotomy of the interphalangeal hallux valgus. Since the surgical procedure the patient is out of any complaints.

DISCUSSION

We demonstrate the radiologic and histologic findings and discuss the relevant literature and possible etiology.

[Femoral nerve palsy due to excessive granuloma in aseptic cup loosening in cementless total hip arthroplasty]

AIM

Femoral nerve palsy after total hip arthroplasty can result from several causes. Delayed neuropathies of the femoral nerve because of excessive granuloma in loosened implants are a rare condition.

CASE REPORT

We report the case of delayed neuropathy of the femoral nerve after cementless total hip arthroplasty because of aseptic loosening of the cup. Electrophysiologic evaluation revealed a severe lesion of the femoral nerve with sensomotoric deficits. An abdominopelvic computed tomography (CT) scan revealed an excessive granuloma with a large intrapelvic portion. After revision of the loosened acetabular component and the femoral nerve and removal of the granuloma the neurologic symptoms improved.

CONCLUSION

Regular (1-2 years) clinical and radiological follow-ups are requested after total hip arthroplasty to prevent excessive loosening of implants, excessive granuloma and severe sequelae like nerve damage.

[Delayed neuropathy of the sciatic nerve after total hip replacement with an acetabular reinforcement ring]

AIM

Lesions of the sciatic or femoral nerve after THR are typical complications. Delayed neuropathies of the sciatic or femoral nerve are rare conditions.

CASE REPORT

We report the case of a delayed neuropathy of the sciatic nerve after THR with reconstruction of the acetabulum with an acetabular reinforcement ring. After electrophysiologic evaluation we performed a revision of the sciatic nerve. Intraoperatively we found an impingement of the sciatic nerve between the dorsal aspect of the acetabular reinforcement ring and scar tissue. After revision of the nerve, resection of the scar tissue and interposition of a fat pad the patient was out of any complaints but reported some sensory deficits of the first toe.

CONCLUSION

Using acetabular reinforcement rings for reconstruction of acetabular defects care has to be taken of the correct position. In anatomically cramped positions a protruding of the dorsal edge of the ring may cause a lesion of the sciatic nerve.

Association between infection with Helicobacter pylori and Chlamydia pneumoniae and risk of ischemic stroke subtypes: Results from a population-based case-control study

BACKGROUND AND PURPOSE

Helicobacter pylori and Chlamydia pneumoniae have been associated epidemiologically and pathogenetically with coronary atherosclerosis. However, population-based data on chronic infection and stroke are lacking. Therefore, we investigated the association of both bacterial pathogens and ischemic stroke subtypes in a population-based case-control study.

METHODS

Patients with first ischemic stroke in the population-based Erlangen Stroke Project were collected as cases. Neighborhood controls were drawn from the study population, matched for age, sex, and place of residence. IgG antibodies to H pylori were measured by enzyme immunoassay, and IgG antibodies to C pneumoniae were measured by microimmunofluorescence technique. Conditional logistic regression was used. Analyses were stratified for etiologic stroke subtypes according to Trial of Org 10172 in Acute Stroke Treatment (TOAST) criteria.

RESULTS

A total of 145 case and 260 control subjects were included. Chronic H pylori infection was associated with a higher risk of stroke caused by small-artery occlusion (adjusted odds ratio, 3.31; 95% CI, 1.15 to 9.56) and a lower risk of cardioembolic stroke (adjusted odds ratio, 0.21; 95% CI, 0.06 to 0.71). Overall, elevated H pylori as well as elevated C pneumoniae antibodies were not associated with ischemic stroke.

CONCLUSIONS

Our population-based study does not provide evidence of any strong association between the immune response to C pneumoniae as a marker of prior infection and ischemic stroke. Further studies are required to reveal the role of chronic H pylori infection as an independent risk factor for the subgroup small-artery occlusion.