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Purpose: Appropriate positioning and alignment of tibial and femoral component in primary total knee arthroplasty (TKA) are factors of major importance directly related to patient satisfaction and implant survival. Most literature works elaborate on overall post-operative alignment and its correlation to implant survival. However, less is known about the impact of individual component alignment. The purpose of this study was to investigate the effect of undercorrection of overall alignment as well as the effect of individual tibial and femoral component alignment on the post-operative failure rate after total knee arthroplasty. Methods: Clinical and radiographic data of primary TKA cases from 2002 to 2004, with a minimum of 10-year follow-up, were retrospectively reviewed. The pre- and post-operative hip–knee–ankle angle (HKA), mechanical lateral distal femoral angle (mLDFA) and mechanical medial proximal tibial angle (mMPTA) were measured on weight-bearing, full-length antero-posterior lower limb radiographs. Statistical analysis was performed to establish the correlation between both overall and implant alignment and revision rate. Results: In total, 379 primary TKA cases were evaluated. The mean time of follow-up was 12.9 years (range 10.3–15.9 years, SD = 1.8). Nine out of 379 cases were revised due to aseptic loosening; the mean time to revision was 5.5 years (range 1.0–15.5 years, SD = 4.6). Varus undercorrection of overall alignment was not associated with a higher rate of revision (p = 0.316). Post-operative valgus femoral alignment (mLDFA < 87°) contributed to a significant decreased prosthesis survival in contrast to neutral femoral alignment (revision rate valgus group: 10.7% and neutral group: 1.7%; p = 0.003). Post-operative tibial mechanical alignment was not identified as a significant predictor for implant survival (revision rate varus group: 2.9% and neutral group: 2.4%; p = 0.855). Conclusions: Primary TKA showed significantly higher revision rates when the femoral component was placed in > 3° of valgus (mLDFA < 87°). In contrast, postoperative overall residual varus alignment (HKA) and varus alignment of the tibial component were not related to higher revision rates at a minimum 10-year follow-up after TKA. These findings should be considered when choosing component position in individualised TKA. Level of evidence: III. [ABSTRACT FROM AUTHOR]

Purpose: This study was set up to identify the native trochlear geometry and define its relationship with the rotational landmarks of the distal femur.Methods: The rotational landmarks of the distal femur were analysed on CT-scans of 281 patients with end-stage knee osteoarthritis.Results: The anterior trochlear line (ATL) was on average 4.3° (SD 3.3°) internally rotated relative to the surgical transepicondylar axis (sTEA). The ATL was on average 2.1° (SD 3.0°) internally rotated relative to the posterior condylar line (PCL). The relationship between the ATL and the sTEA was statistically different in the different coronal alignment groups (p = 0.004): 3.9° (SD 3.0°) in varus knees, 4.0° (SD 2.9°) in neutral knees and 5.4° (SD 3.8°) in valgus knees. The lateralisation of the trochlea, represented by the distance between the perpendicular to PCL and the perpendicular to the posterior parallel line to the sTEA, was on average 2.2 mm (SD 1.8 mm).Conclusion: The ATL was on average 4.3° (SD 3.3°) internally rotated relative to the sTEA and 2.1° (SD 3.0°) internally rotated relative to the PCL. The ATL is more externally orientated in varus knees and more internally rotated in valgus knees. The trochlear groove is lateralised by only 2.2 mm when the femoral component is externally rotated.Level Of Evidence: III. [ABSTRACT FROM AUTHOR]

Purpose: Flexion in a stiff total knee arthroplasty (TKA) can be improved by manipulation under anaesthesia (MUA). Although this intervention usually results in an improvement in range of motion, the expected result is not always achieved. The purpose of this study is to determine which factors affect range of motion after manipulation in patients with a stiff total knee.Methods: After exclusion (n = 22), the data of 158 patients (138 knees) with a stiff knee after TKA who received a manipulation under anaesthesia between 2004 and 2014 were retrospectively analysed. Pre-, peri- and post-operative variables were identified and examined for their influence on flexion after the manipulation using Kruskal-Wallis and Mann-Whitney U tests and Spearman correlations.Results: After MUA, a mean improvement in flexion of 30.3° was observed at the final follow-up. Preoperative TKA flexion, design of TKA and interval between TKA procedure and MUA were positive associated with an increase in flexion after MUA. MUA performed 12 weeks or more after TKA procedure deteriorated the outcome.Conclusions: Three factors, pre-TKA flexion type of prosthesis and interval between TKA procedure and manipulation under anaesthesia, were found to have impact on flexion after TKA and MUA were identified. Results are expected to be inferior in patients with low flexion before TKA procedure or with a long interval (>12 weeks) between the TKA procedure and the manipulation under anaesthesia.Level Of Evidence: IV. [ABSTRACT FROM AUTHOR]

Purpose: In this study, the value of the adductor tubercle as landmark for joint line reconstruction in revision total knee arthroplasty (TKA) was investigated. Methods: On 100 calibrated full-leg standing radiographs obtained from healthy volunteers, distances from the medial epicondyle, the lateral epicondyle, the adductor tubercle, the fibular head and the centre of the knee to the joint line were determined. Results: The average distance to the joint line from the medial epicondyle, the lateral epicondyle, the adductor tubercle and the fibular head was found to be 27.7 mm (SD 3.0), 27.1 mm (SD 2.7), 44.6 mm (SD 4.3) and 15.1 mm (SD 3.7), respectively. The distance from the adductor tubercle ( R = 0.82) and the centre of the knee ( R = 0.86) to the joint line showed a strong and linear correlation with the femoral width. The medial epicondyle, the lateral epicondyle and the fibular head showed less strong correlations. There was no significant correlation with the limb alignment. The adductor ratio was defined as the distance from adductor tubercle to the joint line divided by the femoral width and was found to be 0.52 (SD 0.027) with only small inter-individual variation. The adductor ratio was the most accurate ratio and reconstructed the joint line within 4 mm of its original level in 92 % of the cases. Conclusion: The adductor ratio is a reliable and accurate tool for joint line reconstruction in revision TKA. It was found to be more accurate then the use of absolute distances and the epicondylar ratios. This study supports the use of the adductor tubercle for joint line reconstruction in revision TKA. Level of evidence: II. [ABSTRACT FROM AUTHOR]

Purpose: The goal of this study was to document the outcome at midterm follow-up of 19 patients treated for lateral osteoarthritis of the knee between 1999 and 2007. It was our hypothesis that the results and complication rate would be comparable to or better than those reported in the literature for closing wedge or alternative open wedge techniques. Methods: All patients underwent an open wedge distal femoral varisation osteotomy using the Puddu plate system combined with calcium phosphate injection into the defect. Knee Society Knee Score and Kellgren-Lawrence osteoarthritis score were assessed preoperatively and at final follow-up. Results: The average knee score improved significantly from 43 ± 8 preoperatively to 78 ± 23 at final follow-up. The Kellgren-Lawrence osteoarthritis score remained unchanged. Kaplan-Meier analysis using revision surgery or conversion to TKA as an endpoint demonstrated an 82 % successful survivorship at 7 years of follow-up. Conclusion: Based upon these results, we believe that a distal femoral varisation osteotomy using the Puddu plate and injectable bone cement is an equivalent treatment option compared to closing wedge techniques and leading to good results at midterm follow-up in patients with lateral gonarthrosis and valgus alignment. Level of evidence: IV. [ABSTRACT FROM AUTHOR]

Most surgeons believe that varus deformity leads to progressive tightness of the medial soft tissue envelope and laxity on the lateral side. It is, however, unclear at what stage of the deformity such ligament alterations occur, and whether these are the consequence of intrinsic alterations in the ligaments themselves, or rather due to extrinsic factors such as osteophytes, adhesions to the underlying bone, or other factors which may cause a tightening effect. Thirty-five varus knees that were scheduled for TKA were investigated. Ligament status was evaluated after temporary correction of alignment and removal of osteophytes, using varus/valgus testing with computer navigation technology. Knees with <10° varus deformity were easily correctable to neutral after correction of the extrinsic factors that could cause medial tightness, and these knees maintained normal mediolateral laxity during varus/valgus stress testing. When coronal plane deformity exceeded 10°, progressive shortening of the medial collateral ligament was noted, as well as progressive stretching of the lateral structures ( P < 0.001). This study, therefore, demonstrates that the medial collateral structures become intrinsically shortened when preoperative varus deformity exceeds 10°. Likewise, the lateral soft tissues become stretched. None of these occur when the preoperative deformity is <10°. [ABSTRACT FROM AUTHOR]

Post-steroid septic arthritis can be treated with irrigation pump assisted arthroscopic synovectomy. The high-intra-articular fluid pressures can force the pyogenic fluid into a pre-existing Baker's cyst. The cyst can rupture and with the pre-existing steroid induced immune-suppression, the calf abscess will be hard to control. Therefore, thorough investigation with an ultrasound-guided aspiration followed by an early drainage of the collection is warranted and mandatory. Close monitoring for the development of a deep thrombosis of the popliteal vein is required. [ABSTRACT FROM AUTHOR]

Total knee arthroplasty in the valgus knee poses specific problems to the surgeon, such as the presence of ligament tightness on the lateral side. It has been claimed in the past that approaching the knee from the lateral side through a lateral parapatellar arthrotomy may therefore be a more logical and easier technique than the standard medial approach used conventionally. Many surgeons however do not wish to change their routine practice and therefore wish to stick to the classical medial approach they are used to, even in the presence of an underlying valgus deformity. In this paper, we therefore report the technical considerations that one should take into account when addressing the valgus knee through a standard medial approach. These include tightness of the lateral soft tissues, stretching of the medial collateral ligament, lateral bowing of the femoral shaft, and a tendency for lateralized patellar tracking. A review of 125 consecutive valgus knees treated at our institution through a standard medial approach while using these principles, has demonstrated an excellent operative outcome in the majority of cases. [ABSTRACT FROM AUTHOR]

Many surgeons believe that increasing the tibial slope in total knee arthroplasty (TKA) is beneficial with regard to maximal postoperative flexion. Review of the clinical literature, however, does not confirm this hypothesis, neither does it give an answer to the question of how much flexion gain can be expected per degree extra tibial slope. The purpose of this study was, therefore, to evaluate and quantify the influence of tibial slope on maximal postoperative flexion in contemporary posterior cruciate ligament (PCL)-retaining TKA. Twenty-one cadaver simulations of a standard PCL-retaining TKA were studied while reproducing identical deep flexion femorotibial kinematics as documented by three-dimensional computer-aided videofluoroscopy from patients with well-functioning TKAs of the same design. In each knee the tibial component was consecutively implanted with 0 degrees posterior slope, 4 degrees posterior slope, and 7 degrees posterior slope. Maximal flexion was recorded for each configuration. Average maximal flexion at 0 degrees tibial slope was 104 degrees, and increased significantly to 112 degrees when the same knees were implanted with 4 degrees tibial slope. Increasing the slope further to 7 degrees again significantly improved average maximal flexion to 120 degrees. When postoperative radiographic tibial slope was compared to maximal flexion, an average gain of 1.7 degrees flexion for every degree extra tibial slope was noted. Increasing the tibial slope in PCL-retaining TKA does indeed improve maximal flexion before tibial insert impingement occurs against the femoral bone. The surgeon can expect an average gain of 1.7 degrees flexion for every degree extra tibial slope. [ABSTRACT FROM AUTHOR]