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The choice of implant used for primary total knee arthroplasty (TKA) may have an impact on clinical outcomes. Clinical outcomes after TKA with gradually reducing radius implants (group G) vs single-radius implants (group S) were evaluated among Asian patients. This study included 541 patients (754 knees) in group G and 187 patients (275 knees) in group S. Range of motion (ROM), flexion contracture, American Knee Society Knee and American Knee Society Function scores (KSKS and KSFS, respectively), and mechanical and anatomic tibiofemoral angles (MTFA and ATFA, respectively) were evaluated with electronic medical records. In univariate analysis, improvements in ROM, KSKS, and KSFS were significantly better in group G compared with group S at 1-year follow-up. Multivariable analyses showed greater ROM (4.52°, P =.002), decreased flexion contracture (−2.80°, P =.011), and improved KSKS (15.57, P Orthopedics . 2022;45(6):367–372.]

A new tibial baseplate of the cobalt-chrome (CoCr) prosthesis has an enhanced design with additional cement pockets and undersurface with increased roughness compared with the original baseplate. This study aimed to compare the incidence of medial proximal tibial resorption (MPTR) in total knee arthroplasties (TKAs) with the original and new CoCr tibial baseplates.Each of 200 posterior stabilized TKAs with the original (Group O) and new (Group N) CoCr tibial baseplates with a minimum follow-up period of 2 years were retrospectively reviewed. The matches were made according to age, sex, body mass index, and severity of varus deformity. The occurrence of MPTR was investigated with a radiograph at 2 years postoperatively. MPTR was categorized as type U (resorption under the tibial baseplate; associated with stress shielding), C (resorption around the penetrated cement under the baseplate; associated with thermal necrosis), and M (resorption on the medial tibial cortex without extension to the baseplate; associated with bony devascularization).The incidence of MPTR was 35% in group O and 24% in group N (p = 0.021) at postoperative 2 years. The U type of MPTR occurred more frequently in group O (26 vs. 15%, p = 0.009). There were no significant differences in the incidence of types C and M MPTR.The modified design of the CoCr tibial baseplate affected the incidence of MTPR. The new tibial baseplate was more advantageous in preventing MPTR than the original baseplate in TKAs using the CoCr prosthesis.III.

Intra-articular injection of adipose-derived mesenchymal stem cell (ADMSC) after medial open-wedge high tibial osteotomy (MOWHTO) would be a promising disease-modifying treatment by correcting biomechanical and biochemical environment for arthritic knee with varus malalignment. However, there is a paucity of clinical evidence of the treatment. This randomized controlled trial (RCT) was aimed to assess regeneration of cartilage defect, functional improvement, and safety of intra-articular injection of ADMSCs after MOWHTO compared with MOWHTO alone for osteoarthritic knee with varus malalignment. This RCT allocated 26 patients into the MOWHTO with ADMSC-injection group (n = 13) and control (MOWHTO-alone) group (n = 13). The primary outcome was the serial changes of cartilage defect on periodic magnetic resonance imaging (MRI) evaluation using valid measurements until postoperative 24 months. Secondary outcomes were the 2-stage arthroscopic evaluation for macroscopic cartilage status and the postoperative functional improvements of patient-reported outcome measures until the latest follow-up. Furthermore, safety profiles after the treatment were evaluated. Cartilage regeneration on serial MRIs showed significantly better in the ADMSC group than in the control group. The arthroscopic assessment revealed that total cartilage regeneration was significantly better in the ADMSC group. Although it was not significant, functional improvements after the treatment showed a tendency to be greater in the ADMSC group than in the control group from 18 months after the treatment. No treatment-related adverse events, serious adverse events, and postoperative complications occurred in all cases. Concomitant intra-articular injection of ADMSCs with MOWHTO had advantages over MOWHTO alone in terms of cartilage regeneration with safety at 2-year follow-up, suggesting potential disease-modifying treatment for knee OA with varus malalignment.

The study aims to analyze long-term clinical and radiographic results, and survival of re-revision total knee arthroplasty (TKA) using fully cemented stems performed on femurs with diaphyseal deformation.Thirty-seven re-revision TKAs using fully cemented stems performed in femoral diaphyseal deformations, characterized as diaphyseal canal enlargement and cortex deformation due to aseptic loosening of previously implanted stems, between 2003 and 2015 were retrospectively reviewed. The mean follow-up period was 10.0 years. Clinically, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and range of motion (ROM) were evaluated. Radiographically, mechanical axis (MA) and component positions were measured. Complications and survival rates were also analyzed.Clinically, the WOMAC significantly improved at final follow-up (61.2 vs 47.2, p 0.001), but not the ROM (95.5 vs 102.5, p = 0.206). Radiographically, the MA and component positions were appropriate, with no changes in component positions from immediately post-operative to final follow-up, but with MA change from varus 2.9° to 3.7° (p = 0.020). Two cases (5.4%) with history of previous infections developed periprosthetic joint infection (PJI). Debridement with polyethylene insert exchange following antibiotic suppression were performed in those cases because of concern for difficult implant-cement removal. The five and ten year survival rates were 100% and 93.2%, respectively.Fully cemented stems are viable in providing long-term satisfactory survival after re-revision TKA in patients with femoral diaphyseal deformation. However, it should be used carefully for those with previous infections.

A small posterior tibial slope (PTS) is generally recommended in posterior stabilized (PS) total knee arthroplasty (TKA). An unwanted anterior tibial slope (ATS), which can affect postoperative results, may be created in PS TKA because of the inaccuracy of surgical instruments and techniques, as well as high inter-patient variability. We compared mid-term clinical and radiographic results of PS TKAs with ATS and PTS performed on paired knees using the same prosthesis. One-hundred-twenty-four patients who underwent TKAs with ATS and PTS on paired knees using ATTUNE® posterior-stabilized prostheses were retrospectively reviewed after a minimum follow-up period of 5 years. The mean follow-up period was 5.4 years. The Knee Society Knee and Function scores, Western Ontario and McMaster Universities Osteoarthritis Index, Feller and Kujalar scores, and range of motion (ROM) were evaluated. The preferred TKA out of ATS and PTS was also investigated. The hip-knee-ankle angle (HKA), component positions, tibial slope, posterior femoral offset (PFO), Insall–Salvati ratio (ISR), and knee sagittal angle were measured by radiography. There were no significant differences in the clinical results, including ROM, between TKAs with ATS and PTS preoperatively and at the last follow-up. Regarding patient preference, 58 patients (46.8%) were satisfied with bilateral knees, 30 (24.2%) preferred knees with ATS, and 36 (29%) preferred knees with PTS. There was no significant difference in the rate of preference between TKAs with ATS and PTS (p=0.539). Except for the postoperative tibial slope (-1.8° vs. 2.5°, p

One-week staged bilateral open-wedge high tibial osteotomies (OWHTOs) can be a safe procedure, with the added advantage of fast functional recovery, cost saving, and reduced hospital stay. However, there can be concerns about correction loss after 1-week staged OWHTOs because high loading is inevitably applied to osteotomy sites during postoperative weight bearing. Although leaving the osteotomy site with no grafts is possible in OWHTOs, the use of grafts can provide additional stability to the osteotomy site and prevent correction loss. We compared the amount and incidence of correction loss between 1-week staged bilateral OWHTOs with and without allogenic bone grafts. Seventy-five patients who underwent 1-week staged bilateral OWHTOs with a locking spacer plate (Nowmedipia, Seoul, Korea) by a single surgeon were retrospectively reviewed. Allogenic cancellous bone grafts were applied in 53 patients (group G; 106 knees, operated consecutively between 2012 and 2017) but not in 22 patients (group N; 44 knees, operated consecutively between 2017 and 2019). Demographics were similar between the groups. Radiographically, the mechanical axis (MA), medial proximal tibial angle (MPTA), and posterior tibial slope (PTS) were evaluated preoperatively and within 1 year postoperatively. Unstable hinge fracture was investigated using computed tomography in all cases. The incidence of correction loss (MPTA loss ≥ 3 degrees) was determined. There were no significant differences in the MA, MPTA, and PTS between the groups preoperatively and 2 weeks postoperatively. The incidence of unstable hinge fractures did not differ. The losses in MA, MPTA, and PTS during the first postoperative year were significantly greater in group N than in group G (MA, −5.5 vs. −2.3 degrees; MPTA, −3.0 vs. 0 degrees; PTS, −2.0 vs. −0.7 degrees; p

One-week staged bilateral open-wedge high tibial osteotomies (OWHTOs) can be a safe procedure, with the added advantage of fast functional recovery, cost saving, and reduced hospital stay. However, there can be concerns about correction loss after one-week staged OWHTOs because high loading is inevitably applied to osteotomy sites during postoperative weight bearing. Although leaving the osteotomy site with no grafts is possible in OWHTOs, use of grafts can provide additional stability to the osteotomy site and prevent correction loss. We compared the amount and incidence of correction loss between one-week staged bilateral OWHTOs with and without allogenic bone grafts. Seventy-five patients who underwent one-week staged bilateral OWHTOs with a locking spacer plate (Nowmedipia, Seoul, Korea) by a single surgeon were retrospectively reviewed. Allogenic cancellous bone grafts were applied in 53 patients (Group G; 106 knees, operated consecutively between 2012 and 2017), but not in 22 patients (Group N; 44 knees, operated consecutively between 2017 and 2019). Demographics were similar between the groups. Radiographically, the mechanical axis (MA), medial proximal tibial angle (MPTA), and posterior tibial slope (PTS) were evaluated preoperatively and within 1 year postoperatively. Unstable hinge fracture was investigated using computer tomography in all cases. The incidence of correction loss (MPTA loss ≥ 3°) was determined. There were no significant differences in the MA, MPTA, and PTS between the groups preoperatively and 2 weeks postoperatively. The incidence of unstable hinge fractures did not differ. The losses in MA, MPTA, and PTS during the first postoperative year were significantly greater in group N than in group G (MA, -5.5° vs. -2.3°; MPTA, -3.0° vs. 0°; PTS, -2.0° vs. -0.7°; p0.05° on all parameters). The correction loss incidence was 6.6% (7/106) and 31.8% (14/44) in groups G and N, respectively (p0.001). Appropriate treatment is necessary to prevent correction loss in one-week staged bilateral OWHTOs. Grafting, which provides additional stability to the osteotomy site, is a recommended method.

Backgroud One recently developed total knee arthroplasty (TKA) prosthesis was designed to alter the patellofemoral geometry and optimize patellar tracking compared to its predecessor. Despite an expectation that the improved design would contribute to optimal patellofemoral compatibility, its effect has not been confirmed with patellofemoral-specific clinical scoring systems and radiographic parameters. Our purpose was to compare patellofemoral-specific clinical and radiographic results after TKA using a patellofemoral design-modified prosthesis and its predecessor. Methods The results of 200 TKAs with Attune (group A) were compared to those of 200 TKAs with PFC Sigma (group B). Clinically, the presence of anterior knee pain (AKP), patellar crepitation, and Kujala score were checked. Radiographically, anterior femoral offset (AFO), posterior femoral offset (PFO), position of patellar ridge, and patellar tilt and translation were compared. Results In group A, AKP and patellar crepitation occurred less frequently (AKP: 3% vs. 8%, p = 0.028; patellar crepitation: 2.5% vs. 9%, p = 0.005) and Kujala score was higher (81.8 vs. 77.9, p < 0.001), when compared to group B. The AFO decreased in group A postoperatively but increased in group B (-1.2 vs. 1.1 mm, p < 0.001). The change in PFO was smaller in group A than group B (-1.2 vs. -3.6 mm, p < 0.001). The change in patellar ridge after TKA was smaller in group A than group B (1.4% vs. 8.3%, p < 0.001). The postoperative patella of group A was more laterally tilted (5.9° vs. 2.2°, p < 0.001) and less laterally translated (0.9 vs. 2.6 mm, p < 0.001). The proportion of incompatible patella tilt angle (≥ ± 10°) was greater in group A than group B (21.7% vs. 4.5%, p < 0.001). Conclusions TKA using Attune provided better patellofemoral-specific clinical results and favorable radiographic parameters related with patellar ridge, AFO, and PFO than TKA using PFC Sigma did. However, the current prosthesis did not provide better radiographic patellar tracking, which might be due to the medial location of the patellar ridge.

Recent literature has implicated a thick cobalt chromium baseplate as a potential source of stress shielding and medial tibial bone resorption after total knee arthroplasty (TKA) in a Western population. The purpose was to calculate the incidence of various types and severity of medial tibial bone resorption utilizing a novel classification system after TKA with a thick cobalt chromium baseplate in Asian patients. Five hundred TKAs using Attune prostheses with mean follow-up of 3.4 years were evaluated, using the prospective radiographic data. The mean age was 71.3 years. The preoperative mechanical axis was varus, 11.2 degrees. The type and severity of medial tibial bone resorption were categorized as type U (resorption under the tibial baseplate up to 50% [U1] or beyond 50% [U2] of medial tibial tray width), C (resorption around the penetrated cement under the baseplate), and M (resorption on the medial tibial cortex without extension to the baseplate). Bone resorption of medial proximal tibia was observed in 96 knees (19.2%). Types U1 and U2 were seen in 46 and 28 knees, respectively. Type C was observed in 12 knees and type M in 10 knees. The type U resorption group had significantly more preoperative varus deformity (varus 12.9 vs. 10.9 degrees, p = 0.017). Medial tibial bone resorption after TKAs using a thick cobalt chromium baseplate is not uncommon and has various locations, types, and severities. The medial tibial bone resorption might be related to various causes, including stress shielding, thermal necrosis from cement in the bony hole, and bony devascularization. The type-U resorption has to be closely observed in patients with preoperative severe varus deformity. This is a Level IV study.

Background:Previous studies have reported patellofemoral cartilage degeneration and analyzed the factors affecting degeneration after open-wedge high tibial osteotomy (OWHTO). However, no studies have evaluated patellofemoral cartilage degeneration or examined the factors affecting degeneration after closed-wedge high tibial osteotomy (CWHTO).Purpose:To investigate and compare patellofemoral cartilage degeneration after CWHTO and OWHTO via arthroscopic evaluation and to analyze the factors affecting the degeneration.Study Design:Cohort study; Level of evidence, 3.Methods:A total of 54 CWHTOs and 50 OWHTOs were performed with first-look arthroscopy between 2013 and 2017 at one institution. Hardware removal and second-look arthroscopy were performed, on average, 30.2 months after CWHTO and 26.8 months after OWHTO ( P = .178). Patient characteristics did not differ significantly between the groups. Radiographically, the mechanical axis, posterior tibial slope, and modified Blackburne-Peel ratio were evaluated. Arthroscopically, the percentage of patient with patellofemoral cartilage degeneration was evaluated according to the International Cartilage Repair Society grading system. Logistic regression analysis was used to identify the factors affecting patellofemoral cartilage degeneration in terms of demographics and the change of mechanical axis (correction angle), tibial posterior slope angle, and modified Blackburne-Peel ratio. The Anterior Knee Pain Scale was used for clinical comparison between the patellofemoral degenerative and nondegenerative groups.Results:No significant differences were observed in pre- and postoperative radiographic results between the CWHTO and OWHTO groups, except that the postoperative modified Blackburne-Peel ratio was significantly smaller among the OWHTOs. The percentage of patients with patellofemoral cartilage degeneration were 29.6% in the CWHTO group and 44% in the OWHTO group ( P = .156) at second-look arthroscopy. The correction angle was the only significant factor affecting cartilage degeneration in the CWHTO group (odds ratio, 2.324; P = .013; cutoff value, 9.6°) and the OWHTO group (odds ratio, 1.440; P = .041; cutoff value, 10.1°). The postoperative Anterior Knee Pain Scale score was significantly lower in the patellofemoral degenerative group as compared with the nondegenerative group among the OWHTO group (81.6 vs 76.4; P = .039); among the CWHTO group, there was a lower tendency in the degenerative group, but this was without significance (81.1 vs 79.6; P = .367).Conclusion:Patellofemoral cartilage degeneration progressed after CWHTO and OWHTO with large alignment correction. High tibial osteotomy should be selected with careful consideration of the osteoarthritic status of the patellofemoral joint and required correction angle, regardless of applying a closed- or open-wedge technique.

Background: Although medial open-wedge high tibial osteotomy (MOWHTO) is the treatment of choice for patients with mild to moderate osteoarthritis with varus malalignment, concerns about inferior outcomes in patients with preoperative radiological kissing lesion (RKL) remain. Purpose: To compare the mid- to long-term clinical and radiological results and survivorship after MOWHTO in patients with versus without preoperative RKL. Study Design: Cohort study; Level of evidence, 3. Methods: Included were 122 knees in patients who underwent MOWHTO with a medial locked plate and had minimum 5-year follow-up data. The mean age at surgery was 55.9 years (range, 38-65 years), and the mean follow-up was 7.5 years (range, 5-12.8 years). All patients had undergone second-look arthroscopy around 2 years after MOWHTO. The knees were divided into an RKL group (n = 17) and no-RKL group (n = 105) based on preoperative standing radiographs. The authors compared postoperative American Knee Society (AKS) knee and function scores, range of motion, and improvements in AKS scores between groups, as well as hip-knee-ankle angle, medial proximal tibial angle, and joint-line convergence angle from preoperatively to postoperatively. Also compared were the degree of cartilage regeneration between first- and second-look arthroscopy and the survival rate after index surgery. Results: Preoperative AKS scores were significantly lower in the RKL group versus the no-RKL group (AKS knee, 79.6 ± 7.5 vs 83.8 ± 3.9, P = .037; AKS function, 68.8 ± 9.3 vs 76.0 ± 5.1, P = .006). Likewise, postoperative AKS scores were significantly lower in the RKL group versus the no-RKL group (AKS knee: 91.3 ± 4.2 vs 94.4 ± 1.6, respectively, P = .008; AKS function: 90.0 ± 10.0 vs 97.6 ± 4.5, respectively, P = .007). However, all patients had excellent postoperative AKS knee and function scores (>80). Moreover, there were no between-group differences in pre- to postoperative improvement in AKS scores, postoperative radiological changes, or grade of cartilage regeneration. The survival rates in the RKL and no-RKL groups were 100% and 97.1%, respectively ( P ≥ .999). Conclusion: Although the latest clinical scores were lower in the RKL group than in the no-RKL group, comparable results in postoperative clinical improvement, cartilage regeneration, and survivorship were observed in patients with RKL at mid- to long-term follow-up.

To compare the incidence of correction loss and survival rate between closed-wedge and open-wedge high tibial osteotomies (CWHTO and OWHTO, respectively) in patients with osteopenic and normal bone.Retrospective review was conducted for 115 CWHTOs and 119 OWHTOs performed in osteopenic patients [- 2.5 Bone mineral density (BMD) T scores ≤ - 1] and 136 CWHTOs and 138 OWHTOs performed in normal patients (BMD T score - 1) from 2012 to 2019. Demographics were not different between CW- and OWHTOs in osteopenic and normal patients (n.s., respectively). Radiographically, the mechanical axis (MA), medial proximal tibial angle (MPTA), and posterior tibial slope (PTS) were evaluated pre- and postoperatively (2 weeks after HTO). The occurrence of hinge fractures was investigated using radiographs taken on the operation day. The correction change was calculated as the last follow-up value minus postoperative MPTA. Correction loss was defined when the correction change was ≥ 3°. The survival rate (failure: correction loss) was investigated.There were no significant differences in the pre and postoperative MA, MPTA, PTS, and value changes between CW- and OWHTOs in osteopenic and normal patients (n.s., respectively); the incidence of unstable hinge fractures also did not differ significantly (CWHTO vs. OWHTO = 7 vs. 7.6% in osteopenic patients; 2.9 vs. 3.6% in normal patients; n.s., respectively). The average correction change (CWHTO = - 0.6°, OWHTO = - 1.3°, p = 0.007), incidence of correction loss (CWHTO = 1.7%, OWHTO = 9.2%, p = 0.019), and 5-year survival rates (CWHTO = 98.3%, OWHTO = 90.8%, p = 0.013) differed significantly in osteopenic patients; there were no significant differences in these results in normal patients (n.s., respectively).CWHTO was more advantageous than OWHTO regarding the correction loss in osteopenic patients. Intra- and postoperative care that consider poor bone quality will be required when performing OWHTOs in osteopenic patients.III.

Background Although total knee arthroplasty (TKA) in hemophilic arthropathy (HA) or rheumatoid arthritis (RA) can improve functional ability, the postoperative range of motion (ROM) and prosthesis durability are reduced compared with those in osteoarthritic patients. Aim We aimed to compare (1) the pre- and postoperative flexion contracture after TKA in HA and RA, (2) the threshold of preoperative flexion contracture as a predictor of residual contracture > 15° after TKA, and (3) the survival rate. Methods Data from a consecutive cohort comprising 48 TKAs in HA and 92 TKAs in RA were retrospectively reviewed. The degree of flexion contracture was analyzed. Through receiver operating characteristics analysis, we aimed to determine the cutoff value of preoperative flexion contracture that increases the risk of residual contracture > 15° after TKA and compare the cutoff value in HA and RA. The survival rate was evaluated based on life table analysis and the Kaplan–Meier method. Results The degree of preoperative flexion contracture was not significantly different. The degree of postoperative residual flexion contracture was 5.6° in the HA group and 1.4° in the RA group, respectively (p 15° at last-follow up was 25.0° in the HA group and 32.5° in the RA group. The 5- and 12-year survival rates were 96% and 87% in the HA and 99% and 95% in the RA group, respectively (n.s.). Conclusions The postoperative residual flexion contracture was greater and the cutoff value of preoperative flexion contracture for residual contracture was smaller in the HA group than the RA group. Appropriate intra- and postoperative care to avoid postoperative residual contracture is required in HA patients. Level of evidence III.

The purpose of this study was to assess continuous gaps in the replaced knee throughout the full range of motion (ROM) after total knee arthroplasty (TKA) using a joint stability graph, and to analyze the gap laxity in the mid-flexion range. Ninety-three TKAs were performed using imageless navigation with a joint stability graph. While positioning guides for each respective cut, the surgeon can safely preview the resection's impact for the resulting joint gaps and control the soft tissue balance at the knee flexion of 0° (extension) and 90° (flexion). The gaps between the femoral component and insert were evaluated throughout the full ROM using the joint stability graph. The mechanical axis (MA) and change of joint line height were radiographically evaluated. Posthoc power analyses using a significant α value of 0.05 were performed on the proportion of the mid-flexion instability as a primary outcome to determine whether the sample had sufficient power. The power was determined to be sufficient (100%). The flexion–extension gap differences in each medial and lateral compartment and the mediolateral gap differences in flexion and extension were all ≤3 mm. None of the knees had mid-flexion instability, which is defined by a peak mid-flexion gap that is 3 mm greater than the smaller value of flexion or extension gap. The average MA was well corrected from varus 11.4° to varus 1.0° postoperatively. The proportion of postoperative well-aligned knees (MA ≤ 3°) was 87.1%. The joint line height was well preserved (14.7 vs. 14.8 mm, p = 0.751). The joint stability graph in TKA using the navigation can effectively evaluate the continuous gap throughout the ROM, including the mid-flexion range. Mid-flexion instability was uncommon in primary TKAs with appropriate alignment and proper preservation of the joint line. The Level of evidence for the study is IV.

Background Many surgeons have determined the surgical transepicondylar axis (sTEA) after distal femur resection in total knee arthroplasty (TKA). However, in most navigation systems, the registration of the sTEA precedes the distal femur resection. This sequential difference can influence the accuracy of intraoperative determination for sTEA when considering the proximal location of the anatomical references for sTEA and the arthritic environment. We compared the accuracy and precision in determinations of the sTEA between before and after distal femur resection during navigation-assisted TKA. Methods Ninety TKAs with Attune posterior-stabilized prostheses were performed under imageless navigation. The sTEA was registered before distal femur resection, then reassessed and adjusted after distal resection. The femoral component was implanted finally according to the sTEA determined after distal femur resection. Computed tomography (CT) was performed postoperatively to analyze the true sTEA (the line connecting the tip of the lateral femoral epicondyle to the lowest point of the medial femoral epicondylar sulcus on axial CT images) and femoral component rotation (FCR) axis. The FCR angle after distal femur resection (FCRA-aR) was defined as the angle between the FCR axis and true sTEA on CT images. The FCR angle before distal resection (FCRA-bR) could be presumed to be the value of FCRA-aR minus the difference between the intraoperatively determined sTEAs before and after distal resection as indicated by the navigation system. It was considered that the FCRA-bR or FCRA-aR represented the differences between the sTEA determined before or after distal femur resection and the true sTEA, respectively. Results The FCRA-bR was −1.3 ± 2.4° and FCRA-aR was 0.3 ± 1.7° (p p Conclusions The FCR was more appropriate when the sTEA was determined after distal femur resection than before resection in navigation-assisted TKA. The reassessment and adjusted registration of sTEA after distal femur resection could improve the rotational alignment of the femoral component in navigation-assisted TKA. Level of evidence IV.

To analyze the incidence of intraoperative mid-flexion laxity using continuous flexion-arc gap assessment, risk factors for mid-flexion laxity, and clinical results in navigation-assisted total knee arthroplasty (TKA).Ninety posterior-stabilized TKAs were performed under navigation guidance for patients with degenerative arthritis and varus deformity. Intraoperatively, the gap between the trial femoral component and insert was evaluated in the navigation system with continuous flexion-arc gap assessment. Each medial and lateral gap at flexion (90°) and extension (0°) were made to be less than 3 mm. Mid-flexion laxity was determined when the gap in the flexion range between 15° and 60° was 3 mm or more. The proportion of knees with mid-flexion laxity was investigated. The factors affecting mid-flexion laxity were identified in terms of demographics, preoperative convergence angle, and change in joint line height and posterior femoral offset. The Knee Society Score and Western Ontario and McMaster Universities Osteoarthritis Index were evaluated.There were 31 cases (34.4%) of lateral mid-flexion laxity (average peak mid-flexion gap = 3.7 mm). The other 59 cases did not show mid-flexion laxity. The preoperative convergence angle was the only significant factor affecting lateral mid-flexion laxity (odds ratio = 1.466, p = 0.002). There were no significant differences in the clinical results between the groups with and without mid-flexion laxity.The continuous flexion-arc gap assessment was useful in evaluating mid-flexion laxity using navigation-assisted TKA. The preoperative convergence angle, reflecting soft-tissue laxity, can be a practical and simple radiographic finding for predicting lateral mid-flexion laxity.IV.

This 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.From 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.Mean 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.Increased 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.

Background Whether robot-assisted total knee arthroplasty (TKA) improves the accuracy of radiographic alignment leading to improved patient satisfaction and implant survivorship in the long term has thus far been inconclusive. Methods We retrospectively compared the long-term clinical and radiological outcomes of 84 knees that had undergone robot-assisted TKA using ROBODOC vs 79 knees that had undergone conventional TKA. The mean duration of the follow-up period was 129.1 months (range: 108-147 months). Clinical outcomes were evaluated using the Knee Society Score and 36-item Short Form Survey, as well as by assessing the range of motion, operation time, and complications. Radiologic outcomes were evaluated by assessing the hip-knee-ankle angle, coronal and sagittal alignments of the femoral and tibial components, and any radiologic abnormalities such as loosening or osteolysis. Results There was no significant difference in clinical outcomes between the two groups. The prevalence of an outlier for the hip-knee-ankle angle in the robot-assisted group was 10.7%, whereas it was 16.5% in the conventional group (P = .172). The other component alignments (α°, β°, γ°, δ°) revealed a tendency toward a lower rate of outliers in the robot-assisted group, but without statistical significance (P > .05). In addition, there was no significant difference in complications, including revision surgery, between both groups. Conclusion Robot-assisted TKA does not improve long-term clinical or radiologic outcomes compared with conventional TKA.

Purpose This double-blind, randomized, Phase III clinical trial was conducted to assess the efficacy and safety of the novel divinyl sulfone cross-linked hyaluronate (YYD302) compared with the 1,4-butanediol diglycidyl ether cross-linked hyaluronate (Synovian) in patients with knee osteoarthritis. Methods A total of 184 patients with osteoarthritis (Kellgren-Lawrence grade I–III) were randomized to 1 of 2 study groups (YYD302 group, n = 95; Synovian group, n = 89). A single injection of YYD302 or Synovian was given to both groups, and 182 participants completed the study (YYD302 group, n = 95; Synovian group, n = 87). The primary end point was the change in weight-bearing pain (WBP) at 12 weeks after the primary single injection. Secondary end points included the Knee Injury and Osteoarthritis Outcome Score; the Western Ontario and McMaster Universities Osteoarthritis Index score; the Patient Global Assessment and Investigator Global Assessment; the range of motion, swelling, and tenderness of the target knee; OMERACT-OARSI responder rate; WBP responder rate (the proportion of patients achieving at least 20 mm or 40% decrease in WBP); and rate of rescue medicine use and its total consumption at weeks 2, 4, and 12. Based on the efficacy results at week 12, the responders were administered an additional single injection of the same study drug at week 24, and safety and efficacy were additionally assessed at week 36. Findings Mean changes of WBP at 12 weeks after the primary injection were –31.76 mm with YYD302 and –29.74 mm with Synovian, proving noninferiority of the YYD302 group to the Synovian group as the lower bound of the 95% CI (–4.3 to 8.3) was well above the predefined margin (–10 mm). At week 2, the Knee Injury and Osteoarthritis Outcome Score (total, pain, activities of daily living, and sports/recreation) and Western Ontario and McMaster Universities Osteoarthritis Index scores (total, stiffness) were significantly better in the YYD302 group than in the Synovian group. There were no significant differences between the groups in all other end points. Local overall adverse events (pain, heat, erythema, or swelling) at the injection site were observed in 48.4% of the YYD302 group and in 47.7% of the Synovian group. No serious reactions were reported. There was no statistically significant difference between the 2 groups regarding re-injected patients (YYD302 group, n = 54; Synovian group, n = 46) in any of the efficacy outcomes at week 36. Implications The results of this study support that YYD302 is comparable to Synovian in terms of the efficacy and safety of the intra-articular injection treatment for osteoarthritis of the knee joint. Furthermore, YYD302 provided faster improvements in some efficacy assessments compared with Synovian. ClinicalTrials.gov identifier: NCT03561779.

The purpose was to investigate the proportion of severe load imbalance after appropriate conventional gap balancing and analyze the intraoperative kinematics after load balancing in cruciate-retaining (CR) and posterior-stabilized (PS) total knee arthroplasties (TKAs). In total, 45 sensor-assisted CR and 45 PS TKAs using NexGen prosthesis were prospectively evaluated. After appropriate conventional gap balancing, the loads at 10, 45, and 90 degrees of knee flexion were evaluated with a wireless load sensor placed in trial implants. The proportion of severe load imbalance (medial load–lateral load >75 lbs) was investigated. After load balancing, location of the femorotibial contact point was investigated at each flexion angle to analyze femorotibial kinematics. The proportion of the severe load imbalance was significantly higher in CR TKAs at the 10 degrees knee flexion (37.8 vs. 15.6%, p = 0.031). This proportion was higher in CR TKAs than in PS TKAs at the 45 and 90 degrees knee flexion angles, but without statistical significance (31.1 vs. 15.6%, p = 0.134 and 33.3 vs. 15.6%, p = 0.085, respectively). After load balancing, consistent posterior femoral rollback occurred in medial and lateral compartments during 90 degrees flexion in CR TKAs (p

Background In implants, sensors are made of an acrylic-like plastic, while polyethylene (PE) inserts are made of ultra-high-molecular-weight PE (UHMPE). Thus, the stress distribution on the sensor may be different from that on the PE insert due to variations in material properties. The present study sought to analyze and compare the stress distribution profile between the sensor and PE insert after total knee arthroplasty (TKA). Methods Finite element analysis was performed to estimate contact stress between the sensor and PE insert after TKA. The materials of the femoral component, sensor, and PE insert were determined as cobalt-chrome-molybdenum, acryl plastic, and UHMWPE, respectively. The stiffness levels of medial and lateral soft tissue were set at 28.8 N/mm and 18.8 N/mm at knee flexion and 24.7 N/mm and 17.2 N/mm at knee extension, respectively. The average and peak contact stress levels on the sensor and PE were analyzed in knee flexion and extension. Results The average amount of contact stress in the medial compartment was 43.4 MPa on the sensor and 31.9 MPa on the PE insert at knee extension. Meanwhile, the medial compartmental peak contact stress levels were 55.2 MPa on the sensor and 48.8 MPa on the PE insert at knee extension. The other values of average and peak contact stress among the two materials were less than 5 MPa. Conclusions There was a difference in the contact stress distribution between the sensor and PE insert due to material properties, especially in the medial compartment at knee extension. The development of a sensor composed of a material with properties similar to a PE insert would be useful in the prediction of femorotibial contact stress in real implants.

To compare long-term clinical and radiographic results and survival rates between hybrid and cemented total knee arthroplasties (TKAs) performed on paired knees. Seventy-two patients with hybrid and cemented TKAs performed on paired knees with NexGen® cruciate-retaining prostheses were retrospectively reviewed after a minimum 15 years of follow-up. Mean follow-up period was 17.5 years. Preoperative alignment deformity and range of motion (ROM) were not different between groups. The Knee Society score, Western Ontario and McMaster Universities Osteoarthritis Index, and ROM were evaluated. Radiographically, change in joint space width, component loosening, and osteolysis were evaluated. Implant survival rate was analyzed. There were no significant differences in clinical results between hybrid and cemented TKAs performed on paired knees of 72 patients at the last follow-up. No significant difference was observed in the change in joint space width between the two groups at the last follow-up (medial = 0.3 mm vs. 0.4 mm; lateral = 0.1 mm vs. 0.2 mm). One hybrid TKA showed tibial component loosening, for which revision was performed. There was femoral osteolysis in one hybrid and one cemented TKA, and tibial osteolysis in eight hybrid TKAs and seven cemented TKAs (n.s., respectively). The 20-year survival rate was 97.7% for hybrid TKAs and 100% for cemented TKAs (n.s.). The long-term outcomes were similar between hybrid and cemented TKAs performed on paired knees at a minimum 15 years of follow-up. The method of femoral component fixation did not have a significant effect on long-term TKA success. III.

The incidence of postoperative hyperextension and factors affecting hyperextension needs to be investigated separately for cruciate retaining (CR) and posterior stabilized (PS) total knee arthroplasties (TKAs), because the mechanism for preventing hyperextension is different according to the bearing design. The purpose of the study was to compare the incidence of postoperative hyperextension between CR and PS TKAs and analyze the factors affecting the postoperative hyperextension. Matched 213 CR and PS TKAs with Persona® prosthesis were retrospectively reviewed. The preoperative demographics, clinical and radiographic knee condition, and pelvic incidence were similar between groups. Appropriate knee extension (0°–5°), confirmed with a goniometer, was achieved intraoperatively. The knee sagittal angle was radiographically measured preoperatively and at 2 years postoperative. The incidence of hyperextension (sagittal angle

Background As life expectancy increases, the number of octogenarians requiring primary and revision total knee arthroplasty (TKA) is increasing. Recently, primary TKA has become a common treatment option in octogenarians. However, surgeons may still be hesitant about performing revision TKA on octogenarians because of concern about risk and cost benefit. The purpose of this study was to investigate clinical outcomes, postoperative complications, and mid-term lifetime survival in octogenarians after primary and revision TKA. Materials and methods We retrospectively reviewed 231 primary TKAs and 41 revision TKAs performed on octogenarians between 2000 and 2016. The mean age of patients undergoing primary TKA was 81.9 years and that of patients undergoing revision TKA was 82.3 years (p = 0.310). The age-adjusted Charlson comorbidity index was higher in revision TKA (4.4 vs. 4.8, p = 0.003). The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and range of motion (ROM) were evaluated. The incidence of postoperative complications (TKA-related, specific or systemic) and lifetime survival rate (endpoint death determined by telephone or mail communication with patient or family) were investigated. Results The WOMAC and ROM improved significantly after primary and revision TKA, although postoperative results were worse in the revision group (33.1 vs. 47.2; 128.9° vs. 113.6°; p p = 0.151), and three cases of deep vein thrombosis (DVT)/pulmonary thromboembolism (PTE) (one case of DVT and two cases of PTE) were observed in the primary group (1.3% vs. 0%, p = 1.000). The most common systemic complication in both groups was delirium (7.4% vs. 14.6%, p = 0.131). There were no differences between the two groups in the other systemic complication rates. The 5-year and 10-year lifetime survival rates were 87.2% and 62.9%, respectively, in primary TKA and 82.1% and 42.2%, respectively, in revision TKA (p = 0.017). Conclusions Both primary and revision TKA are viable options for octogenarians, based on the satisfactory clinical outcomes, TKA-related complication rates, and mid-term lifetime survival. Delirium needs to be managed appropriately as the most common systemic complication in both primary and revision TKA in octogenarians. Level of evidence IV

To compare posterior tibial slope (PTS) and incidence of excessive PTS between cruciate-retaining (CR) total knee arthroplasties (TKAs) with the current prosthesis, providing a 1-mm increment of polyethylene insert thickness, and its predecessor, providing a 2-mm increment.Each of 154 CR TKAs with Persona (current group) and NexGen (predecessor group) prostheses with a minimum follow-up period of 2 years were retrospectively reviewed. Preoperative demographics, including age, sex, and body mass index, were similar. Factors affecting the flexion gap were matched in terms of preoperative range of motion, mechanical axis, PTS, preoperative and postoperative posterior femoral offset (PFO), and PFO ratio. The PTS was evaluated radiographically. The incidence of excessive PTS (PTS10°) and the frequency of intraoperative PTS-increasing procedures were investigated.There were no significant differences in preoperative and postoperative range of motion, mechanical axis, PFO, and PFO ratios between the 2 groups. The preoperative PTS was not significantly different, but the postoperative PTS was significantly lower in the current group (4.6° vs 6.2°, P.001). There was no case of excessive PTS in the current group, but there were 9 cases (5.8%) in the predecessor group (P = .030). The intraoperative PTS-increasing procedure was performed more frequently in the predecessor group (12.3% vs 21.4%, P = .047).The current prosthesis providing a 1-mm increment of polyethylene insert thickness could decrease the PTS and the occurrence of excessive PTS in CR TKA. The target angle for PTS can be decreased in TKA using the current prosthesis in comparison with its predecessor.III.

In the present study, the early results of sensor-assisted versus manually balanced posterior-stabilized total knee arthroplasty (TKA) for osteoarthritis with varus deformities were prospectively compared. Fifty patients undergoing sensor-assisted TKA (group S) and 50 patients receiving manually balanced TKA (group M) were prospectively compared. The groups did not differ in terms of demographics, preoperative clinical status, or severity of deformity. The knee and function scores (KS and FS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and range of motion (ROM) were evaluated clinically. The mechanical axes and positions of components were assessed radiographically. In sensor-assisted TKA, the medial and lateral compartment loads were compared based on the patellar positions of inversion and eversion. There was no between-group difference in the postoperative KS or FS (n.s., respectively). The average postoperative WOMAC score was 17.0 in group S and 18.0 in group M (n.s.). The ROM was 131.2° in group S and 130.8° in group M (n.s.). Neither the postoperative alignment of the mechanical axis nor the component positioning differed between the groups (n.s.). In sensor-assisted TKA, the difference between the medial and lateral compartment loads was less than 15 lbs (6.8 kg) in each knee. The lateral compartment load increased after patellar eversion (p

Background This study aimed to assess the morphological degeneration of the anterior cruciate ligament (ACL) through magnetic resonance imaging (MRI) and arthroscopy. It analyzed whether the pre-operative ACL status would affect the radiologic and clinical outcomes following medial open-wedge high tibial osteotomy (MOWHTO). Methods A total of 150 knees were enrolled that underwent MOWHTO concomitant arthroscopic debridement for the treatment of varus osteoarthritis. Mean age was 56.1 ± 5.0 years and mean follow-up was 61.2 ± 21.4 months. The ACLs were staged based on MRI and arthroscopy. To exclude the influence of demographic factors on outcomes, the between-group differences were assessed. Radiologic evaluation included hip–knee–ankle angle, femorotibial angle, medial proximal tibial angle, posterior tibial slope angle, and Kellgren–Lawrence grade. Clinical evaluation included American Knee Society Score (AKSS) and knee joint range of motion (ROM). Results The ACLs were classified into intact (75 knees, 50.0%), mucoid degeneration (59, 39.3%), chronic partial tear (10, 6.7%), and complete tear (six, 4.0%) according to MRI. They were also classified into four stages: normal (95 knees, 63.3%), abnormal (36, 24.0%), partial tear (13, 8.7%), and complete tear (six, 4.0%) according to arthroscopic appearance. There were no significant between-group differences in each variable. Changes in Kellgren–Lawrence grade did not show significant between-group differences. No significant between-group differences were observed in AKSS and ROM. Conclusions The pre-operative status of ACL did not influence the outcomes following MOWHTO at midterm follow-up. Level of evidence Level IV, case series.

The purposes of the present study were to assess the levels of prosthetic constraint chosen during revision total knee arthroplasty (TKA) and to identify factors influencing the choice of a constrained prosthesis. We retrospectively reviewed data on 274 revision TKAs. The mean follow-up period after revision TKA was 7.2 years. The femorotibial angle (FTA), joint line height (JLH), and Insall–Salvati ratio (ISR) were radiographically evaluated. Factors affecting the extent of constraint chosen were evaluated in terms of age, gender, body mass index, primary diagnosis, the cause of revision TKA, the Anderson Orthopedic Research Institute (AORI) classification, and changes in the JLH and ISR. Totals of 247 (90.1%), 11 (4.0%), and 9 (3.4%) knees received posteriorly stabilized prostheses, constrained condylar knees, and rotating hinge prostheses, respectively. On multivariate analysis, the cause of revision TKA including loosening and instability and the changes in the JLH and ISR affected independently the choice of a constrained prosthesis. The frequency of implantation of constrained prostheses was 7.4% in the present study. Consideration of various factors including the cause of revision TKA and changes in the JLH and ISR will aid the TKA surgeon in selecting prostheses with appropriate constraints when performing revision TKAs.

This study was performed to prospectively compare the clinical and radiographic results between mobile-bearing (MB) and fixed-bearing (FB) TKAs using ceramic titanium nitride (TiN)-coated prostheses. Seventy MB and 70 FB TKAs using TiN-coated prostheses (ACS®) were prospectively evaluated. There were no differences in demographic characteristics between the two groups. Clinically, the Knee Society knee and function scores, WOMAC, and range of motion (ROM) were compared. Considering the possibility of a kinematic change in the polyethylene (PE) insert and a decrease in ROM following MB TKA, serial changes in the ROM were also compared. The thickness of the PE insert was compared according to the size of the femoral component. Radiographically, the alignment and positions of the components were compared. There were no differences between the two groups in clinical scores or ROM (n.s.). The maximum flexion increased from 133.5° ± 8.3° to 137.6° ± 5.5° across all time points in the MB group. The serial maximum flexion angles did not differ between the two groups over time (n.s.). The average thickness of the PE insert was greater in the MB group (12.0 ± 1.9 vs. 11.2 ± 1.6 mm, respectively, p = 0.008), especially when a large femoral component was used (12.7 ± 1.9 vs. 11.0 ± 1.5 mm, p = 0.005). The pre- and postoperative mechanical axes and positions of the components did not differ between the two groups (n.s.). TiN-coated MB TKA showed no significant advantage over FB TKA. The selection of bearing design would be clinically insignificant when using the TiN-coated TKA prosthesis. II.

INTRODUCTION The previous studies have described only closed-wedge high tibial osteotomy (HTO) in haemophilic arthropathy (HA). AIM The purpose of this study was to evaluate clinical and radiographic results after open-wedge HTO in HA with varus knee deformity. METHODS We included 13 open-wedge HTOs in HA performed between 2005 and 2016. The mean age of patients was 28.9 years. Visual analogue scale (VAS), Western Ontario and McMaster Universities (WOMAC), and range of motion (ROM) indices were assessed. Any complications or requirements for total knee arthroplasty (TKA) were investigated. Mechanical axis (MA), minimal joint space width (mJSW) and Pettersson score were measured. Bone union rates at 3 and 6 months postoperative were evaluated. RESULTS VAS improved from 5.1 to 2.4 (P

Purpose The purpose of this study was to determine the results of mobile bearing unicompartmental knee arthroplasty (UKA) with an intentionally increased flexion angle of the femoral component in patients requiring high flexion. Materials and methods We investigated 45 knees treated by UKA. Clinically, we measured the range of motion (ROM) and the American Knee Society (AKS) score preoperatively and at final follow-up and investigated complications. Radiologically, we measured the flexion angle of the femoral component, the posterior slope angle of the tibial component, the femorotibial angle and mechanical axis of the limb postoperatively. Results The ROM was increased from 123° preoperatively to 139° at the final follow-up. The AKS knee and function scores increased from 59 and 68, respectively, preoperatively to 94 and 96, respectively, at the final follow-up. The flexion angle of the femoral component was 9.1°, and the posterior slope angle of the tibial component was 8.6°. There was one case of bearing dislocation in the largest femoral flexion angle case. Conclusions The results might reflect the positive effect of an increased flexion angle of the femoral component up to 10° on ROM in mobile bearing UKA, which would contribute to better quality of life after UKA especially in populations requiring deep knee flexion.

We compared clinical and radiographic results after total knee arthroplasty (TKA) using Attune and Press Fit Condylar Sigma, and investigated whether use of the current prosthesis increased injury risk to the tibial cortex in Asian patients. We also assessed whether a preoperative posterior tibial slope angle (PSA) is associated with the injury when using the current prosthesis.The 300 TKAs with Attune (group A) were compared to the 300 TKAs with Press Fit Condylar Sigma (group B). Demographics were not different, except follow-up periods (24.8 vs 33.3 months, P .001). The Western Ontario and McMaster Universities Index and range of motion were compared. A minimum distance between tibial component stem and posterior tibial cortex (mDSC) was compared. The correlation between preoperative PSA and mDSC was analyzed in group A.The postoperative Western Ontario and McMaster Universities Index and range of motion of group A were better than those of group B (17.7 vs 18.8, P = .004; 131.4° vs 129.0°, P = .008). The mDSC was shorter in group A (6.3 vs 7.0 mm, P.001), which made up a higher proportion of the high-risk group for posterior tibial cortical injury with an mDSC of4 mm (20.0% vs 10.7%, P = .002). A negative correlation was found between the preoperative PSA and mDSC in group A (r = -0.205, P.001).The TKA using the current prosthesis provided more satisfactory results than the TKA using the previous prosthesis. However, the injury risk to the posterior tibial cortex increased in the knees with a large PSA when using the current prosthesis for Asian patients.

Background: There have been little data concerning serial changes in the joint space width (JSW) and joint line convergence angle over the course of follow-up periods after closed-wedge high tibial osteotomy (CWHTO). Purpose: To evaluate serial changes in the JSW and joint line convergence angle after CWHTO. Study Design: Case series; Level of evidence, 4. Methods: A total of 100 computer-assisted CWHTOs with a minimum follow-up period of 3 years (mean, 4.4 years) were analyzed. Clinically, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score was evaluated. Radiographically, the mechanical axis was measured preoperatively and postoperatively. The minimal JSW was measured as the shortest distance between the femur and the tibia. The convergence angle was measured as the angle between the tangent to the subchondral plates of the femoral condyle and the tibial plateau. Serial changes in these measurements were analyzed preoperatively; at 3 months, 6 months, 1 year, and 2 years postoperatively; and at the final follow-up. The intraclass correlation coefficients for all measurements were greater than 0.8. Results: The mean WOMAC score improved from 41.4 preoperatively to 14.9 at the final follow-up. The preoperative and postoperative mean mechanical axis was 8.1° varus and 1.6° valgus, respectively. The mean minimal JSW was 2.5, 2.9, 2.9, 3.1, 3.2, and 3.1 mm preoperatively and at 3 months, 6 months, 1 year, 2 years, and the final follow-up, respectively ( P < .001). The mean convergence angle was 4.4°, 3.9°, 4.0°, 4.1°, 4.2°, and 4.3°, respectively, during the same time periods ( P = .068). Conclusion: Cartilage healing, as indicated by the JSW, and clinical improvement were maintained over the minimum 3-year follow-up after CWHTO. Cartilage pressure, as indicated by the convergence angle, remained unchanged after CWHTO.

Background The purpose of this study was to compare mid-term clinical and radiographic results of conversion total knee arthroplasties (TKA) following a closed-wedge high tibial osteotomy (HTO) and primary TKAs. Methods A total of 32 conversion TKAs (29 patients) were compared with a matched control group of patients who had undergone primary TKA. The clinical results were evaluated using the Knee Society Knee and Function score, the Western Ontario and McMaster Universities score, patella score, and range of motion (ROM). The radiographic results were evaluated using femorotibial angle, mechanical axis (MA), the method employed by the American Knee Society, joint line height (JLH), the amount of tibial bone resection, and the Insall–Salvati ratio. The clinical and radiographic results of conversion TKAs were compared with primary TKAs. The thickness of the polyethylene insert was also compared. Results No significant differences were observed in the clinical scores or ROM between two groups. No significant differences were detected in femorotibial angle, MA, and position of the components between two groups. The amount of tibial bone resection and pre-operative JLH both were significantly lower in the conversion group than those in the control group, although postoperative JLH and pre and postoperative Insall–Salvati ratio did not differ between two groups. No significant difference in the thickness of the polyethylene insert was identified between two groups. Conclusions The previous closed-wedge HTO itself had no detrimental effect on the mid-term outcome of the subsequent TKA, including patellar symptom and position. No significant differences in the postoperative joint line and patella height were detected between the conversion and primary TKA groups.

The aim of this study was to investigate the overall incidence of venous thromboembolism (VTE) and to assess the efficacy of chemoprophylaxis to prevent VTE following medial open-wedge high tibial osteotomy (MOWHTO) in Asian patients. A total of 133 patients who consecutively underwent MOWHTO for the treatment of knee osteoarthritis with varus deformity were enrolled. All patients underwent preoperative ultrasonography and computed tomography venography on postoperative day 5 to detect deep vein thrombosis (DVT). Patients were divided into two groups: chemoprophylaxis group included patients (n = 66) who received 2.5 mg fondaparinux for 5 days postoperatively, whereas control group comprised patients (n = 67) who received placebo (67 patients). We evaluated the efficacy and safety outcomes of the treatment. We also assessed the predisposing factors that may affect the occurrence of VTE. The incidence of overall DVT was 14.9% in the control group and 10.6% in the chemoprophylaxis group (p > 0.05). Proximal DVT occurred in one patient in the control group. There was no symptomatic DVT or pulmonary embolism in either group. The patients with DVT had significantly higher mean body mass index (BMI) than the patients without DVT. Multivariate logistic regression showed BMI > 30 kg/m2 that was significantly correlated with the development of DVT (odds ratio = 0.8; p = 0.017). There were no cases of major bleeding; however, minor bleeding episodes occurred in four patients in the chemoprophylaxis group. The current study showed that the overall incidence of VTE following MOWHTO was low in Asian patients even without chemoprophylaxis. Therefore, routine chemoprophylaxis following MOWHTO seems to be not necessary in a population with low-VTE incidence. However, selective chemoprophylaxis should be considered in patients with BMI > 30 kg/m2.

Purpose: The purpose of this study was to compare the daily blood loss transition between groups with and without topical administration of tranexamic acid (TXA) after cruciate retaining (CR) and posterior stabilized (PS) total knee arthroplasty (TKA). Methods: A total of 220 patients undergoing unilateral TKA were enrolled in CR and PS TKAs, which were divided into groups that received topical administration of TXA (TXA group) or without TXA (non-TXA group). Each group in both types of TKA included 55 patients. The daily transition of blood loss was compared between the TXA and the non-TXA groups in CR and PS TKAs. The blood loss was calculated through Nadler formula using the patient’s blood volume and hemoglobin reduction rate. Results: Total blood loss was significantly lower in the TXA group in both CR and PS TKAs ( p < 0.001, respectively). The blood loss was lower for 0–24 h and 24–48 h after TKA. However, from 48 h to 72 h, it was greater in the TXA group (253.1 vs. 34.6 mL; p < 0.001) in CR TKAs. These tendencies were similar in PS TKAs after 48 h (186.2 vs. 134.9 mL, p = 0.223). Conclusions: Topical administration of TXA for reduction of blood loss seemed to be effective up to 48 h after both CR and PS TKAs. The blood loss after 48 h tended to be even greater in the TXA group. Future studies will be required to identify the pharmacokinetic evidence for this clinical finding. Level of evidence: Level II.

To systematically review and evaluate novel clinical data following microfracture treatment of knee articular cartilage defects.A systematic review was performed by searching PubMed, ScienceDirect, and Cochrane Library databases for clinical trials on microfracture treatment, published between 2013 and 2018. Titles, abstracts, and articles were reviewed, and data concerning patient demographics, study design, pre-, intra-, and postoperative findings were extracted. PRISMA guidelines were applied. The methodological quality of the included studies was analyzed by the modified Coleman Methodology Score (CMS), and aggregate data were generated.Eighteen studies including 1830 defects (1759 patients) were included. Of them, 8 (59% of patients) were cohort studies without a comparison group. Overall study quality was moderate (mean total CMS: 64 points), mainly due to low patient numbers, short follow-up periods, lack of control groups and structural repair tissue evaluation, and inhomogeneity in outcome parameters. Microfracture treatment of full-thickness articular cartilage defects (3.4 ± 2.1 cmMicrofracture provides good function and pain relief at the mid-term and clinically largely satisfying results thereafter. Standardized, high-quality future study designs will better refine optimal indications for microfracture in the context of cartilage repair strategies.This systematic review is based on studies with levels of evidence ranging between I and IV (see results section and Table). Therefore, and according to this journals Instructions for Authors (SYSTEMATIC REVIEWS AND META-ANALYSES are assigned a level of evidence equivalent to the lowest level of evidence used from the manuscripts analysed), level of evidence is IV.

Background We compared the incidence of aseptic component loosening and subsequent revision, and the survival rate between ceramic titanium-nitride-coated mobile bearing (MB) and fixed bearing total knee arthroplasties (TKAs) performed in patients with moderate to severe varus deformities. Methods In total, 200 TKAs using advanced coated system posterior stabilized prostheses in varus deformity of mechanical axis >8° between 2012 and 2016 were retrospectively reviewed. One hundred MB (ceramic-m group) and 100 fixed bearing (ceramic-f group) prostheses were included. The matches were made according to preoperative demographics, range of motion, and severity of deformity. The mean follow-up period was not different (ceramic-m vs ceramic-f = 4.8 vs 5.1 years; P = .104). The incidence of revision TKA due to aseptic component loosening and the survival rate (failure: revision due to aseptic loosening) was investigated. Results The incidence of revision TKA due to aseptic component loosening was 7 (7%) in the ceramic-m group and 1 (1%) in the ceramic-f group (P = .032). All cases of aseptic loosening occurred at the tibial component. The overall survival rate was 91.3% in the ceramic-m group and 98.9% in the ceramic-f group (P = .025). Conclusion Considering the higher revision incidence and lower survival rate due to tibial component loosening, caution should be taken in tibial component fixation when using advanced coated system MB prosthesis in moderate to severe varus deformity. Level of Evidence III

Background There is debate regarding the influence of a surgeon’s experience with computer-assisted surgery (CAS) on the postoperative mechanical axis (MA) in CAS-high tibial osteotomy. The purpose of the present study was to compare radiographic results between early and late cohorts of a consecutive series of patients to assess the influence of CAS experience on accuracy and precision of the postoperative MA during CAS lateral closing-wedge high tibial osteotomy (LCWHTO). Materials and methods Results from 140 CAS-LCWHTO operations were retrospectively reviewed. The first 70 cases, performed during the learning curve period for CAS between 2005 and 2009, were considered to be the “early cohort.” The subsequent 70 cases, performed with greater CAS experience after the completion of the learning curve between 2009 and 2014, were considered to be the “late cohort.” The target postoperative MA angle was valgus 3°. Pre- and postoperative MA angles were evaluated by navigation and radiographs. The proportion of postoperative MA inliers (≤ target angle ±3°) was investigated radiographically. The correlation between the navigation and radiographic measurements was analyzed. Results The average postosteotomy MA angle on navigation was 3.4° in both cohorts. The average postoperative MA angle on radiographs was 1.0° in the early cohort and 2.2° in the late cohort (P = 0.003). Radiographically, the proportion of postoperative MA inliers was greater in the late cohort than in the early cohort (early versus late, 71.4% versus 90%; P = 0.011). The pre- and postoperative correlation between navigation and radiographic measurements was also stronger in the late cohort (early versus late; preoperative r = 0.558 versus 0.663; postoperative r = 0.310 versus 0.376). Conclusions Greater experience with CAS increased the accuracy and precision of postoperative MA alignment as well as the correlation between navigation and radiographic measurements. Caution should be taken during registration procedures to achieve accurate alignment correction in CAS-LCWHTO.

To evaluate intercompartmental load intraoperatively with a sensor after conventional gap balancing with a tensiometer during total knee arthroplasty (TKA). Fifty sensor-assisted TKA procedures were performed prospectively between August and September 2018 with a cruciate-retaining prosthesis. After applying a modified measured resection technique, conventional balancing between resected surfaces was achieved. The equal and rectangular flexion–extension gaps were confirmed using a tensiometer at 90° and 5°–7° (due to posterior tibial slope) of knee flexion. Then, the load distribution was evaluated intraoperatively with a sensor placed on trial implants in the positions of knee flexion (90° flexion) and extension (10° flexion). The proportion of coronal load imbalance (medial load − lateral load ≥ ± 15 lb) was 56% in extension and 32% in flexion (p = 0.023). The proportion of sagittal load imbalance (extension load − flexion load ≥ ± 15 lb) was 36% in the medial compartment and 4% in the lateral compartment (p

Various techniques to release the superficial MCL (sMCL) during medial open-wedge high tibial osteotomy (MOWHTO) has been introduced. However, there have been debates regarding the extent of sMCL release in MOWHTO. The authors present a pie-crust technique that involves selective and gradual release of sMCL from inside using a small, round-tip blade after opening the gap. The aims were to introduce our novel technique regarding sMCL release and evaluate the clinical and radiologic outcomes. One-hundred sixty-six knees underwent this procedure. With a mean 60.3 months' follow-up, clinical scores were significantly improved after index operation (p

We compared the medium-term results of total knee arthroplasty (TKA) performed using computer-assisted surgery (CAS) and conventional techniques in patients with extraarticular femoral deformities.The clinical and radiographic data of 40 knees (34 patients) with extraarticular femoral deformities that underwent consecutive CAS-TKA were compared with those of a control group that underwent conventional TKA (80 knees, 63 patients). No demographic data (in particular, the causes of the extraarticular deformities) differed between the two groups. The follow-up periods of the CAS and conventional TKA groups were 6.0 and 6.3 years, respectively.In the CAS group, the average knee score increased from 48.2 to 89.6 at the final follow-up (P .001); the average function score increased from 51.4 to 91.4. The range of motion averaged 105.5° preoperatively and 123.3° postoperatively. No significant differences were found in the knee score, function score, or range of motion after TKA between the 2 groups. The average preoperative mechanical axes were 18.1° varus in both groups. The average postoperative mechanical axis was 1.4° varus in the CAS group and 3.3° varus in the conventional TKA group (P = .001). The proportion of postoperatively aligned knees was 77.5% in the CAS group and 32.5% in the conventional group (P.001).Although the medium-term clinical results of TKA in extraarticular femoral deformities were satisfactory in both the CAS and conventional TKA groups, the former group exhibited more accurate postoperative coronal alignment. It was useful to employ navigation in patients with extraarticular deformities of various etiologies.

Clinical results of high tibial osteotomy (HTO) deteriorate over time despite the initial satisfactory results. Several knees may require a conversion to total knee arthroplasty (TKA) because of failure such as the progression of degenerative osteoarthritis and the loss of the correction angle. It is important to know the long-term survival rate and common reason of failure in HTO to inform patients of postoperative expectations before surgery and to prevent surgical errors during surgery. In addition, it has been reported that clinical and radiological results, revision rate, and complication rate were poorer than those in patients without a previous HTO. There are few review articles that describe why conversion TKA after HTO is surgically difficult and the results are poor. Surgeons have to avoid the various complications and surgical errors in this specific situation. We would like to present the considering factors and technical difficulties during conversion TKA after HTO with a review of the literature. We could conclude through the review that the correction of deformity, lower amount of tibial bone resection, and sufficient polyethylene insert thickness, restoration of the joint line height, and adequate ligament balancing can be helpful in overcoming the technical challenges encountered during TKA following HTO.

We evaluated the incidence of medial cortical fracture and influence on the loss of the correction angle in computer-assisted closing-wedge high tibial osteotomy.Using a navigation system, 200 closing-wedge high tibial osteotomies were performed. The correction angle was defined as the difference between the pre- and postoperative medial proximal tibial angles. The change in the medial proximal tibial angle was calculated as the difference between the medial proximal tibial angles two weeks and one year postoperatively. The medial cortical fractures of the osteotomy site were evaluated. Their incidence, risk factors, and influence on the loss of correction angle were analyzed.The incidence of non-displaced cortical breakage and displaced cortical fracture was 28.0% and 6.5%, respectively. Medial cortical fracture was more frequent in younger patients and patients with severe preoperative varus deformity. The average correction angle was significantly larger in the displaced cortical fracture group (9.6° vs. 12.7°, p0.001). The average change in the medial proximal tibial angle in the no fracture, non-displaced cortical breakage, and displaced cortical fracture groups was 0.7°, 1.8°, and 4.4°, respectively (p0.001).Medial cortical fracture could not be prevented in all knees, even using the navigation system. The risk of medial cortical fracture and loss of the correction angle was increased, particularly when a greater correction angle is required in young patients.IV.