A comparative study of bone shortening and bone loss with use of saw blades versus burr in hallux valgus surgery

BackgroundThe aim of this study was to assess bone loss and thickness of the cut with the use of a burr in percutaneous hallux valgus surgery.MethodsTwelve blocks of saw bone were used. Cuts of same depth were made in each block with two different saw blades and a burr. Each block was assessed for bone loss and thickness of the cut.ResultsThere was statistically significant (p < 0.05) increased bone loss and thickness of the cuts with the use of a burr as compared to use of two different saw blades. The use of a burr resulted in threefold increased loss of bone material and fourfold increase in the thickness of the cut as compare to use of two different saw blades.ConclusionThe metatarsal shortening is a risk factor in percutaneous hallux valgus surgery with the use of a burr.     

Temperature influence in different orthopaedic saw blades.

Laboratory tests were carried out on ox bone to evaluate the thermal effect of eight different saw blades while cutting cortical bone. These saw blades represented the usual clinical blades as well as saw blades specially manufactured in an attempt to decrease the temperature. Temperatures between 34 degrees C and 450 degrees C were registered in the saw blades. Only three measurements (of 219 tests) were below 44 degrees-47 degrees C, which is a critical limit for heat-induced bone necrosis. This test indicates that alternating saw blade design is not a way to control the temperature elevation during cutting of bone in orthopaedic procedures.     

Better Implant Positioning and Clinical Outcomes With a Morphometric Unicompartmental Knee Arthroplasty. Results of a Retrospective,Matched-Controlled Study

BackgroundDuring medial unicompartmental knee arthroplasty (UKA), tibial tray implantation requires compromise between bone coverage and rotational position. It was hypothesized that morphometric tibial tray (MTT) would improve implant positioning and subsequently clinical outcomes as compared to symmetric tibial tray (STT).MethodsA total of 106 patients who underwent medial UKA in our department between January 2017 and March 2018 were included matched on gender and age (53 in each group). Inclusion criteria were symptomatic medial femorotibial osteoarthritis, functional anterior cruciate ligament, primary arthritis, or osteonecrosis. Rotation of the tibial implant, tibial bone coverage, medial and posterior overhang were assessed with a postoperative computed tomography scan. The Knee Society Score (KSS), the Knee injury and Osteoarthritis Outcome Score Short Form (KOOS SF), and the quality of life score EuroQoL 5-Dimensions 3-Levels (EQ5D3L) were assessed at a minimum of 1-year follow-up.ResultsImplants of the STT group exhibited more external rotation (6.3° ± 4.02° vs 4.6° ± 3.59°; P = .04), and medial and posterior overhang >3 mm (35% vs 0% and 22% vs 0%; P < .0001) but no difference for tibial bone coverage (97.3% ± 11.35% vs 94.7% ± 10.89%; P = .23). Global KSS (188.6 ± 6.6 vs 175.2 ± 31.7; P < .01), KOOS SF (16.9 ± 6.1 vs 22.5 ± 11.8; P < .003), and EQ5D3L (1 ± 0.1 vs 0.9 ± 0.2; P < .001) were higher in MTT group. According to the multivariate analysis, MTT had a positive independent effect on the KSS, KOOS SF, and EQ5D3L.ConclusionThe use of an MTT in medial UKA allowed better implant positioning when decreasing the rate of overhang; superior short-term clinical outcomes were found as compared to STT.     

Tibial tunnel enlargement after anatomic anterior cruciate ligament reconstruction with a bone–patellar tendon–bone graft. Part 1: Morphological change in the tibial tunnel

BackgroundThree-dimensional (3D) computed tomography (CT) is reliable and accurate imaging modality for evaluating tunnel enlargement after anterior cruciate ligament (ACL) reconstruction. The purpose of this study was to evaluate the tibial tunnel enlargement including the morphological change after anatomic ACL reconstruction with a bone–patellar tendon–bone (BTB) graft using 3D CT models.MethodsEighteen patients with unilateral ACL rupture were included. The anatomic rectangular-tunnel (ART) ACL reconstruction with a BTB autograft was performed. 3D CT models of the tibia, the tibial tunnel, and the bone plug at 3 weeks and 1 year after surgery were reconstructed and superimposed using a surface registration technique. The cross-sectional area (CSA) of the tibial tunnel perpendicular to the tunnel axis was evaluated at the aperture and 5, 10, and 15-mm distal from the aperture. The CSA was measured at 3 weeks and 1 year after surgery and compared between the two time points. The locations of the center and the anterior, posterior, medial, and lateral edges of the tunnel footprint were also evaluated based on the coordinate system for the tibial plateau and compared between the two time points.ResultsAt the aperture, the CSA of the tibial tunnel at 1 year after surgery was significantly larger by 21.9% than that at 3 weeks (P < 0.001). In contrast, the CSA at 1 year was significantly smaller than that at 3 weeks at 10 and 15-mm distal from the aperture (P = 0.041 and < 0.001, respectively). The center of the tunnel footprint significantly shifted postero-laterally with significant posterior shift of the anterior/posterior edges and lateral shift of the lateral edge (P < 0.001).ConclusionThe tibial tunnel enlarged at the aperture by 22% 1-year after anatomic ACL reconstruction with a BTB graft, and the tunnel morphology changed in a postero-lateral direction at the aperture and into conical shape inside the tunnel.     

A Biomechanical Comparison of the Effect of Baseplate Design and Bone Marrow Fat Infiltration on Tibial Baseplate Pullout Strength

BackgroundEarly clinical results of a new total knee arthroplasty (TKA) implant design show promise for improved outcomes and patellofemoral function scores. However, reports of early tibial component-cement interface debonding requiring revision have been published. This study investigated the biomechanical properties of three different tibial baseplates to understand potential causes of failure.MethodsPFC Sigma (control), Attune (1st generation) and Attune S+ (2nd generation) tibial baseplates were implanted into 4th generation sawbone tibia models using a standardized technique. Three of each baseplate were cemented with and without additional bovine bone marrow fat. All models were tested to failure with measured axial distraction force. Implant type, presence or absence of bovine marrow and load to failure were all recorded and compared. Two-way ANOVA followed by post-hoc pairwise comparisons were used to determine statistical significance, which was set to P < .05.ResultsThe 2nd generation tibial baseplates required significantly more force to failure. The presence of bovine marrow significantly reduced the pullout force of the implant designs overall. No significant difference was detected between the 1st generation and control baseplates. Failure mode for each model was also noted to be different irrespective of the presence or absence of bone marrow fat.ConclusionThe 2nd generation baseplates required significantly more force to failure compared with older designs. The presence of bone marrow during cementation of a tibial base plate significantly decreased axial pullout strength of a tibial baseplate in this laboratory model. All 1st generation baseplates exhibited debonding at the cement-implant interface.     

Locking plate osteosynthesis in displaced 4-part fractures of the proximal humerus

Background Metal particles are generated during bone preparation in knee arthroplasty. These particles may produce third-body wear, or may have a role in osteolysis. Knowledge of their characteristics may help in the development of methods to reduce the amount of metal debris during bone cutting procedures.

Material and methodsWe performed bony resection of the distal femur and proximal tibia on 15 pig knees, simulating a total knee arthroplasty (TKA). Metal debris was collected from the saw blades, cutting blocks and bone surfaces and cleaned for microanalysis.

Results The average loss of metal from the saw blades was 1.13 mg. The average volume of a wear particle was 3.4 × 10^-16m³. From this, it was estimated that approximately 500,000 particles are released from the saw blade alone. Material analysis of the particles indicated that the majority originated from the metallic cutting guides, suggesting that many millions of wear particles would be generated during the surgical procedure. Two particle shapes predominated: platelet shape and ploughed shape.

Interpretation Wear particles are produced during resection for a TKA. These may enter the artificial articulation and cause accelerated wear and macrophage activation. Redesign of cutting blocks and saw blades may reduce the amount of debris produced during surgery.     

The Influence of Iodine-Impregnated Incision Drapes on the Bacterial Contamination of Scalpel Blades in Joint Arthroplasty

BackgroundProsthetic joint infections (PJI) are a disastrous and feared complication in arthroplasty. Over the past decades, surgeons have tried to lower infection rates through all sorts of improvements. At present, it is impossible to reduce the risk to zero. As the contamination of surgical instruments and the surgical field has been identified as a remaining gap prone for infection, scalpel blades among others have become a focal point of several studies. This study is the first to compare the effect of adhesive incision drapes on contamination rates of scalpel blades in primary arthroplasty of the hip and knee.MethodsA total of 344 microbiologic blade culture results from 2 study groups with and without drape usage and 1 group with known PJI were analyzed and compared to histopathologic and microbiologic tissue results.ResultsIn 78% of all positive cultures, the bacteria were part of the local skin flora. The contamination rate for the skin blades with a drape was 3.81% vs 12.19% without drape usage. A significant difference was determined between positive skin blade culture results incision drape usage (P = .031). The different pathogens likely responsible for the PJI correlated with the deep blade cultures (P ≤ .01). The overall contamination rate of surgical blades (1.37%) is comparatively low to the results obtained from other surgical equipment in literature. None of those blade-positive patients developed a surgical site infection during 12-month follow-up.ConclusionIodine-impregnated incision drapes are able to reduce surgical skin blade contamination. Further studies may be needed to assess the relationship between blade contamination and surgical site infections.     

What Is the Critical Tibial Resection Depth During Unicompartmental Knee Arthroplasty? A Biomechanical Study of Fracture Risk

BackgroundFracture after medial unicompartmental knee arthroplasty (UKA) is a rare complication. Biomechanical studies evaluating association between depth of resection and maximum load to failure are lacking. The purpose of this study is to establish the relationship between depth of resection of the medial tibial plateau and mean maximum load to failure.MethodsMedial tibial resections were performed from 2 to 10 mm in 25 standardized fourth-generation Sawbones composite tibias (Sawbones, Vashon Island, Washington). A metal-backed tibial component with a 9-mm polyethylene bearing was used (Stryker PKR). Tibias were mounted on a biomechanical testing apparatus (MTESTQuattro) and axially loaded cyclically 10 times per cycle and incrementally increased until failure occurred.ResultsLoad to failure was recorded in 25 proximal tibia model samples after medial UKA using sequential resections from 2 to 10 mm. Analysis of variance testing identified significant differences in mean maximum load to failure between groups (P = .0003). Analysis of regression models revealed a statistically significant fit of a quadratic model (R² = 0.59, P = .0001). The inflection point of this quadratic curve was identified at 5.82 mm, indicating that the maximum load to failure across experimental models in this study began to decline beyond a resection depth of 5.82 mm.ConclusionIn this biomechanical model, medial tibial resections beyond 5.82 mm produced a significantly lower mean load to failure using a quadratic curve model. Resections from 2 to 6 mm showed no significant differences in mean load to failure. Identification of the tibial resection depth at which the mean load to failure significantly decreases is clinically relevant as this depth may increase the risk of periprosthetic fracture after a medial UKA.     

Neutral Mechanical Alignment Alters the Native Distal Femoral Joint Line: A Virtual Three-Dimensional Planning Total Knee Arthroplasty Study

BackgroundAlternative alignment concepts have garnered great interest in an effort to improve patient satisfaction following primary total knee arthroplasty (TKA). The purpose of this study is to determine variation or deviation from an individual’s native joint line in primary TKA using neutral mechanical versus a restricted kinematic technique.MethodsAn institutional review board–approved prospective cohort study was performed evaluating the effect of neutral mechanical alignment (nMA) versus a restricted kinematic alignment (rKA) on the native joint line in 100 consecutive patients undergoing primary TKA. Using preoperative computed tomography and intraoperative 3-dimensional software, 2 virtual preoperative plans were created: nMA and rKA. Templated bone resections were recorded. Change in joint line was calculated using known implant planar thickness and planned bone resection.ResultsnMA yielded significantly greater deviation from the patient’s native joint line along the lateral compartment of the knee (lateral distal femoral condyle, lateral posterior femoral condyle, lateral tibial resection). With nMA, the lateral distal femoral joint line was distalized by a mean 4.3 versus 2.6 mm using rKA technique (P < .001). In rKA, >60% of knees had <3 mm of deviation from the native lateral posterior femoral offset, whereas in nMA, >95% of knees had ≥3 mm change in the lateral posterior femoral condylar offset.ConclusionnMA-TKA resulted in statistically larger joint line deviations compared to rKA-TKA, most notably along the lateral distal femoral condyle joint line. Further analysis is needed to determine the clinical consequences of joint line deviation from the native anatomy using nMA as the target for primary TKA.     

Partial and Combined Partial Knee Arthroplasty: Greater Anterior-Posterior Stability Than Posterior Cruciate–Retaining Total Knee Arthroplasty

BackgroundLittle is known regarding anterior-posterior stability after anterior cruciate ligament–preserving partial (PKA) and combined partial knee arthroplasty (CPKA) compared to standard posterior cruciate–retaining total knee arthroplasty (TKA).MethodsThe anterior-posterior tibial translation of twenty-four cadaveric knees was measured, with optical tracking, while under 90N drawer with the knee flexed 0-90°. Knees were tested before and after PKA, CPKA (medial and lateral bicompartmental and bi-unicondylar), and then posterior cruciate–retaining TKA. The anterior-posterior tibial translations of the arthroplasty states, at each flexion angle, were compared to the native knee and each other with repeated measures analyses of variance and post-hoc t-tests.ResultsUnicompartmental and bicompartmental arthroplasty states had similar laxities to the native knee and to each other, with ≤1-mm differences throughout the flexion range (P ≥ .199). Bi-unicondylar arthroplasty resulted in 6- to 8-mm increase of anterior tibial translation at high flexion angles compared to the native knee (P ≤ .023 at 80-90°). Meanwhile, TKA exhibited increased laxity across all flexion angles, with increased anterior tibial translation of up to 18 ± 6 mm (P < .001) and increased posterior translation of up to 4 ± 2 mm (P < .001).ConclusionsIn a cadaveric study, anterior-posterior tibial translation did not differ from native laxity after PKA and CPKA. Posterior cruciate ligament–preserving TKA demonstrated increased laxity, particularly in anterior tibial translation.     

Undersizing the Tibial Baseplate in Cementless Total Knee Arthroplasty has Only a Small Impact on Bone-Implant Interaction: A Finite Element Biomechanical Study

BackgroundThe tibial component in total knee arthroplasty (TKA) is often chosen to maximize coverage of the tibial cut, which can result in excessive internal rotation of the component. Optimal rotational alignment may require a smaller baseplate with suboptimal coverage that could threaten fixation. We asked: “does undersizing the tibial component of a cementless TKA to gain external rotation increase the risk of bone failure?”MethodsWe developed computational finite element (FE) analysis models from the computed tomography (CT) scans of 12 patients scheduled for primary TKA. The models were implanted with a cementless tibial baseplate that maximized coverage and one or two sizes smaller and externally rotated by 5°. We calculated the risk of bone collapse under loads representative of stair ascent.ResultsUndersizing the implant increased the area at risk of collapse for eight patients. However, the area at risk of collapse for the undersized implant (range, 5.2%-16.4%) was no different (P = .24) to the optimally sized implant (range, 4.5%-17.9%). The bone at risk of collapse was concentrated along the posterior edge of the implant. The area at risk of collapse was not proportional to implant size, and for four subjects undersizing the implant actually decreased the area at risk of collapse.ConclusionWhile implants should maximize coverage of the tibial cut and seek support on dense bone, undersizing the tibial component to gain external rotation had minimal impact on the load transfer to the underlying bone. This FE analysis model of a cementless tibial baseplate may require further validation and additional studies to investigate the long-term biomechanical effects of undersizing the tibial baseplate. In conclusion, while surgeons should strive to use the appropriate tibial baseplate for each patient, our model identified only minor biomechanical consequences of undersizing the implant for the immediate postoperative bone-implant interaction and implant subsidence.     

Minimum 5-Year Outcomes of a Multicenter,Prospective, Randomized Control Trial Assessing Clinical and Radiological Outcomes of Patient-Specific Instrumentation in Total Knee Arthroplasty

BackgroundPatient-specific instrumentation (PSI) was developed to produce more accurate alignment of components and consequently improve clinical outcomes when used in total knee arthroplasty. We compare radiological accuracy and clinical outcomes at a minimum of 5-year follow-up between patients randomized to undergo total knee arthroplasty performed using PSI or traditional cutting block techniques.MethodsThis multicenter, randomized control trial included patients blinded to the technique 1used. Outcome measures were coronal alignment measured radiologically, Euroqol-5D, Oxford knee score, and International Knee Society Score measured at 1- and 5-year follow-up.ResultsAt a minimum 5-year follow-up, there were 38 knees in the PSI group and 39 in the conventional instrumentation group for analysis. Baseline demographics and clinical outcome scores were matched between groups. Overall, there was no significant difference in the coronal femoral angle (P = .59), coronal tibial angle (P = .37), tibiofemoral angle (P = .99), sagittal femoral angle (P = .34), or the posterior tibia slope (P = .12) between knees implanted using PSI and those implanted with traditional cutting blocks. On the measurement of coronal alignment, intraobserver reliability tests demonstrated substantial agreement (k = 0.64). Clinical outcomes at both 1-year and 5-year follow-up demonstrated statistically significant and clinically relevant improvement in scores from baseline in both groups, but no difference could be detected between the Euroqol-5D (P = .78), Oxford knee score (P = .24), or International Knee Society Score (P = .86) between the 2 groups.ConclusionThis study has shown no additional benefit to PSI in terms of improved alignment or functional outcomes at minimum 5-year follow-up over traditional techniques.     

Healing of osteotomy sites applying either piezosurgery or two conventional saw blades: a pilot study in rabbits

Purpose

The purpose of this study was to compare bone healing of experimental osteotomies applying either piezosurgery or two different oscillating saw blades in a rabbit model.

Methods

The 16 rabbits were randomly assigned into four groups to comply with observation periods of one, two, three and five weeks. In all animals, four osteotomy lines were performed on the left and right nasal bone using a conventional saw blade, a novel saw blade and piezosurgery.

Results

All three osteotomy techniques revealed an advanced gap healing starting after one week. The most pronounced new bone formation took place between two and three weeks, whereby piezoelectric surgery revealed a tendency to faster bone formation and remodelling. Yet, there were no significant differences between the three modalities.

Conclusions

The use of a novel as well as the piezoelectric bone-cutting instrument revealed advanced bone healing with a favourable surgical performance compared to a traditional saw.     

前交叉韧带损伤与胫骨平台后侧骨损伤的相关性分析

目的探讨前交叉韧带(anterior cruciate ligament,ACL)损伤与胫骨平台后侧骨损伤的相关性。方法纳入我院2010年10月至2017年10月行膝关节MRI的门诊或住院病人581例,年龄为(45.72±11.38)岁(20~79岁);男362例,女219例。分析所有病人的膝关节MRI影像学资料,记录病人ACL损伤程度(轻度损伤/断裂/撕脱骨折)、胫骨平台后侧骨损伤程度(骨挫伤/骨折),以及股骨损伤、半月板和侧副韧带损伤情况,并分析其致伤原因。采用Spearman秩相关分析病人ACL损伤与胫骨平台骨损伤之间的关系,并分析可能的损伤机制。结果581例病人中,ACL轻度损伤440例(75.73%),ACL断裂122例(21.00%),ACL撕脱骨折19例(3.27%)。202例出现胫骨平台后侧骨挫伤,47例出现胫骨平台后侧骨折;152例(61.04%)发生在外侧平台,59例(23.69%)发生在内侧平台,38例(15.26%)发生在双侧平台。Spearman秩相关分析结果显示ACL损伤程度与胫骨平台后侧骨损伤程度呈正相关(r=0.344,P<0.0001)。结论随着ACL损伤程度增加,胫骨平台后侧骨损伤越重,且以胫骨平台后外侧骨损伤为主。     

Four-Millimeter Additional Bone Resection in the Distal Femur Does Not Result in an Equivalent Increase in the Extension Joint Gap in Total Knee Arthroplasty

BackgroundAdditional bone resection in the distal femur is performed to increase the extension joint gap in total knee arthroplasty (TKA). The present study aimed to analyze the relationship between the amount of additional bone resection in the distal femur and the increase in the extension joint gap in TKA.MethodsFifty knees undergoing TKA for varus osteoarthritis were evaluated. Two femoral trial component models were prepared: (1) a normal model with 9-mm-thick distal and posterior femoral components and (2) an additional bone resection model with a 5-mm-thick distal femoral component (9 mm to 4 mm) and a 9-mm-thick posterior femoral component, which simulated an additional bone cut in the distal femur of 4 mm. The femoral trial component models were set before implantation, and the extension joint gap was measured using a tensor device that had a shape identical to that of the fixed-bearing tibial insert.ResultsThe additional bone resection model had a larger joint gap than the normal model (P < .01). The mean extension gap increase in the additional bone resection model was 2 (standard deviation 1) mm, which was less than the thickness of the additional bone resection (4 mm) (P < .01).ConclusionThe amount of additional bone resection in the distal femur was not equal to the increase in the extension joint gap. Additional bone resection of 4 mm in the distal femur only increased the extension joint gap by a mean of 2 mm.     

Preoperative Systemic Bone Quality Does Not Affect Tibial Component Migration in Knee Arthroplasty: A 2-Year Radiostereometric Analysis of a Hundred Consecutive Patients

BackgroundBone quality and other preoperative predictive factors may affect implant migration and the survival of knee arthroplasty.MethodsIn a prospective cohort of 100 consecutive patients (65 women) at a mean age of 67.7 years (range 39-87 years), we investigated preoperative predictors of postoperative tibial component migration in cemented and cementless total knee arthroplasties or cemented unicompartmental knee arthroplasty. Predictors consisted of Knee Injury and Osteoarthritis Outcome Score (KOOS) and Oxford Knee Score, questionnaires, bone turnover markers of CTX and P1NP, systemic bone mineral density (BMD), and knee osteoarthritis (OA) grade. Tibial component migration was measured with radiostereometry postoperative, at 1 and 2 years of follow-up.ResultsBetween 1 and 2 years, 19 tibial components migrated continuously (maximum total point motion [MTPM] > 0.2 mm). In general, there was no difference in age, body mass index, BMD, KOOSs, or OA grade between patients with continuous tibial migration compared to patients without continuous migration (P > .11). However, cementless tibial components with continuous migration had a lower KOOS pain score (more pain), lower vitamin D, and a higher bone turnover (CTX) value than patients without continuous migration. There was no association between the BMD and MTPM at 1-year follow-up regardless of prothesis type (P > .17). Patients with osteoporosis and normal BMD had similar mean tibial component MTPM at 2 years (3 prostheses combined; P = .34).ConclusionMigration of tibial components inserted with or without bone cement was not affected by the preoperative bone quality in terms of systemic BMD, bone turnover markers, and OA grade in the knee.     

钻孔法制造大鼠胫骨缺损性骨折动物模型初探

目的:比较两种缺损性骨折动物模型损伤量、愈合时间和愈合方式的差异,为探索建立新型缺损性骨折动物模型提供研究依据。方法:SPF级雄性SD大鼠60只,随机分为正常组、锯开组和钻孔组3组,每组20只。正常组不做任何处理,其他两组动物经麻醉后,钻孔组用低速骨钻在胫骨平台下外侧钻约1mm的圆孔缺损,缺损应能达到骨髓腔,但不可钻通对侧皮质(此方法为钻孔法);锯开组用骨锯在胫骨平台下外侧锯约3mm左右的缺损,缺损应能达到骨髓腔(此方法为钻开法)。术后2周和4周两个时间点每组取10只动物,检测大鼠胫骨的骨密度、骨灰重、拍摄胫骨X线片并进行胫骨病理切片观察,检测术后2周时骨Ca、P含量。结果:造模后2周,钻孔组和锯开组的骨密度,骨灰重,骨Ca、P含量均明显低于正常组(P<0.05或P<0.01)。钻孔组和锯开组胫骨X线片可见骨折线模糊,病变端密度增高,骨痂形成。钻孔组和锯开组病理切片中均可见新生骨小梁形成。造模后4周时,钻孔组、锯开组与正常组相比骨密度、骨灰重无统计学差异(P>0.05),锯开组胫骨X线片中骨痂较钻孔组明显。钻孔组和锯开组动物胫骨病理切片示骨小梁粗大,并逐步融合成板状骨,锯开组动物骨痂处较钻孔组有较多炎性细胞浸润。结论:钻孔法和锯开法均可建立大鼠胫骨缺损性骨折模型,并且在损伤量接近的情况下,两种模型的愈合时间和方式相近。钻孔法操作相对简单规范,损伤量较易控制,并且较少出现炎性细胞浸润和骨不愈合。     

Hybrid Lateral Closed-Wedge High Tibial Osteotomy Showed Similar Accuracy in Angular Correction and Reduction of Posterior Tibial Slope Compared to Opening-Wedge High Tibial Osteotomy: A Correction Angle Matched Cohort Study

BackgroundWe aimed to compare the accuracy of applied correction angle between hybrid lateral closed wedge high tibial osteotomy (hybrid HTO) and medial open wedge high tibial osteotomy (OWHTO), and verify previous reports on hybrid HTO by matching correction angle between groups. Change in various radiological parameters including union rate were also compared.MethodsA total of 50 OWHTO patients were selected for 2:1 propensity matching with 25 hybrid HTO patients. Rate of correction error was calculated by dividing the difference between the change in medial proximal tibial angle and preoperatively planned correction angle (PRD) by planned correction angle. Accuracy of angular correction was assessed using PRD and correction error rates. Hip-knee-ankle axis, mechanical lateral distal femoral angle, medial proximal tibial angle, joint line convergence angle, and length of the entire lower limb and tibia were measured. The Caton-Deschamps index (CDI) was used to assess change in patellar height. Serial postoperative radiographic analysis was performed to assess the union rate.ResultsThe discrepancy between planned correction angle and real correction angle was 0.8 ± 2.3° in hybrid HTO and 1.1 ± 3.4° in OWHTO (P > .05), and the rate of error in osteotomy was similar between the groups approximately 6%. Postoperatively, posterior tibial slope (PTS) (P < .001), tibia length, and CDI (P < .001) were significantly different between groups. The amount of change in PTS (P < .001), tibia length in hybrid HTO (P < .001), and CDI (P < .001) were significantly different between groups. Union rate of osteotomy site was significantly faster in hybrid HTO than in OWHTO (P < .001).ConclusionHybrid HTO showed similar accuracy in angular correction compared to correction angle-matched OWHTO. Reduction in PTS, tibial shortening, maintained patellar height relative to the proximal tibia, and faster osteotomy site union were also confirmed in hybrid HTO.     

Increased Posterior Tibial Slope After Medial Open-Wedge High Tibial Osteotomy May Result in Degenerative Changes in Anterior Cruciate Ligament

BackgroundThis study aimed at evaluating changes in posterior tibial slope angle (PTSA) and the anterior cruciate ligament (ACL) before and after medial open-wedge high tibial osteotomy (MOWHTO) through 2-staged arthroscopic findings and verified whether the ACLs would be affected by the changed PTSA. We also evaluated which predisposing factors could influence ACL changes after MOWHTO.MethodsFrom July 2010 to March 2016, 164 knees that could follow the second-look arthroscopy at the time of plate removal were enrolled. Radiologically, preoperative and postoperative hip-knee-ankle angle, femorotibial angle, medial proximal tibial angle, and PTSA were evaluated. Based on our previous study, we assessed the ACL using the macroscopic grading system (normal, abnormal degenerative, and partially ruptured ACL) by first- and second-look arthroscopy and compared it before and after HTO. The correlation between changes in PTSA (△PTSA) and ACL was evaluated. We also assessed predisposing factors that might affect ACL changes.ResultsMean age at the time of osteotomy was 57.2 ± 5.1 years and time interval between the 2-stage arthroscopies was 26.3 ± 4.0 months. PTSA significantly increased after MOWHTO (P < .001). ACL stage at second-look arthroscopy was significantly progressed compared to first-look findings (P < .001). △PTSA was larger in the progressed group (2.1°; P < .001). Multivariate logistic regression indicated that greater body mass index (odds ratio, 1.2; P = .029) and larger △PTSA (odds ratio, 1.3; P = .008) were predisposing factors.ConclusionIncreased posterior tibial slope following MOWHTO may result in degenerative ACL changes. Greater body mass index and larger △PTSA were predisposing factors for ACL degeneration after MOWHTO.     

No Difference in Revision Rate Between Low Viscosity and High Viscosity Cement Used in Primary Total Knee Arthroplasty

BackgroundLoosening remains one of the most common reasons for revision total knee arthroplasty (TKA). Cement viscosity has a potential role in reducing revision rates for loosening. The aim of this study was to assess the outcome for loosening of the 5 most used cemented knee prostheses by constraint type, based on the cement viscosity type used.MethodsThere were 214,708 TKA procedures performed between 1999 and 2020 for a diagnosis of osteoarthritis using the 5 most commonly used minimally stabilized, posterior stabilized, and medial pivot design cemented tibial components. Only procedures with a cemented tibial component were included. Outcomes for two different cement viscosities, 140,060 high viscosity and 74,648 low viscosity cement, were compared for each fixation type within each of the three stability groups.ResultsThere was no difference in a risk of all-cause revision when high viscosity cement was used compared to low viscosity cement for minimally stabilized prostheses (hazards ratio [HR] 1.07 [95% CI 0.99-1.15], P = .09), posterior stabilized prostheses (HR 1.03 [95% CI 0.95-1.11], P = .53), and medial pivot design prostheses (HR 1.06 [95% CI 0.80-1.41], P = .67). No difference was observed between cement viscosity types for any of the prosthesis constraint types when aseptic loosening was assessed.ConclusionsWe found no difference in the risk of revision for any reason, or for loosening, with cement viscosity for the most commonly used minimally stabilized, posterior stabilized, and medial pivot TKA. The role of cement viscosity in the risk of TKA revision remains unclear and further research is required.Level of EvidenceLevel III Retrospective comparative study.