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Background: Several studies have reported that graft extrusion after meniscal allograft transplantation (MAT) is associated with deterioration of surgical outcomes. However, no study has investigated the effect of graft extrusion on the articular cartilage using objective quantitative methods. Purpose/Hypothesis: This study aimed to investigate the influence of graft extrusion on the chondroprotective effect of lateral MAT on knee articular cartilage. We hypothesized that MAT without graft extrusion would result in better cartilage quality than MAT with graft extrusion. Study Design: Cohort study; Level of evidence, 3. Methods: Altogether, 105 patients who underwent isolated lateral MAT were divided into the extrusion and nonextrusion groups based on postoperative 3-month magnetic resonance imaging. Quantitative T2 mapping was performed on pre- and postoperative magnetic resonance imaging at midterm follow-up (mean ± SD, 3.2 ± 0.7 years). The weightbearing area of the femoral and tibial plateau articular cartilage was divided into 6 segments (F1, F2, F3, TP1, TP2, and TP3) from the anterior to posterior direction according to the meniscal coverage area. Each segment was further segmented into superficial and deep layers for zonal analysis. Longitudinal change in cartilage T2 value was compared between the groups. Lysholm scores were used to evaluate clinical function. Results: The mean T2 value of the nonextrusion group showed a significant improvement in 14 of 18 segments after lateral MAT, whereas the extrusion group demonstrated no statistically significant change. The biochemical properties of cartilage tissue as judged by quantitative T2 mapping indicated improvement in the nonextrusion group as compared with the extrusion group in the F2, TP2, and TP3 segments overall; the deep layers of the F1, F2, and TP2 segments; and the superficial layer of the TP3 segment ( P < .05). Conclusion: This study shows that the nonextruded graft results in better cartilage properties of the knee joint after lateral MAT as compared with the extruded graft at midterm follow-up.

To evaluate the serial change of magnetic resonance imaging (MRI) signal intensity (SI) of lateral meniscal allografts in a long-term period of 8 years and to determine whether the SI change adversely affected clinical outcomes.Thirty-three lateral meniscal allograft transplantation (LMAT) patients with MRI taken 8 years after surgery were included. The allograft was assessed using MRI at five serial time points (1, 2-4, 4-6, 6-8, and 8 years after surgery), based on the following grading system: grade 1, globular increased SI not adjacent to the articular surface; grade 2, linear SI within the meniscus; and grade 3, increased SI extended to the articular surface. MRI evaluation was performed for three locations of the allograft (anterior horn, mid-body, and posterior horn), and the serial changes of allograft SI at each location were analyzed using the generalized estimating equation (GEE) with cumulative logit link function. The patients were classified according to SI change at each location (stationary group and deterioration group), and the two groups were compared in terms of clinical outcomes using the Lysholm score.The mean follow-up duration was 9.2 ± 1.2 years. During that period, SI of the allograft deteriorated over time, regardless of the location (anterior horn, p = 0.034; mid-body, p = 0.002; posterior horn, p 0.001). The amount of SI deterioration at each location of the graft differed with a borderline significance (p = 0.050, GEE), and the proportion of grade 3 SI was higher at the posterior horn (36.4%) than at the other locations at the last follow-up (p 0.001, chi-square test). However, no significant differences in the Lysholm scores were found between the stationary group and the deterioration group at all locations.SI of the meniscal allograft deteriorated over time at all locations during the long-term follow-up. Deterioration of the graft was more prominent at the posterior horn than at the other locations. SI deterioration did not adversely affect the clinical outcomes, which should be interpreted with caution, considering the small sample size of this study. In the prognosis of lateral MAT, SI deterioration at the posterior horn is a more determining factor than that at the other part of the allograft. Therefore, SI at the posterior horn needs to be examined with special concern.III.

To evaluate the serial changes in the joint space width (JSW) of the medial and lateral compartments after medial open-wedge high tibial osteotomy (MOWHTO) and its associated factors.The medial and lateral weight-bearing JSWs were measured on serial radiographs and analyzed preoperatively and postoperatively within 2 weeks, as well as at 3 months, 6 months, 1 year, and 2 years. Associations between the medial and lateral JSWs and age, body mass index, mechanical axis, correction angle, lateral distal femoral angle, medial proximal tibial angle, joint line convergence angle (JLCA), JLCA on stress radiographs, and arthroscopic cartilage status were examined. Clinical outcome was measured according to the Knee Society objective and functional scores.Seventy-one patients who underwent MOWHTO with locking-plate fixation were analyzed. The respective mean medial and lateral JSWs on serial radiographs were as follows: 3.08 mm and 5.14 mm preoperatively, 3.10 mm and 4.63 mm postoperatively, 3.37 mm and 4.57 mm at 3 months, 3.40 mm and 4.59 mm at 6 months, 3.44 mm and 4.57 mm at 1 year, and 3.42 mm and 4.64 mm at 2 years. At 3 months, the medial JSW increased (P.001), whereas the lateral JSW decreased immediately (P.001). JSW showed no significant differences at other time points. Preoperative and postoperative JLCAs and medial femoral and tibial cartilage grades were associated with medial JSW changes (P = .021). However, no significant parameters were associated with decreases in the lateral JSW (P.05). The postoperative Knee Society objective and functional scores improved and were maintained.After MOWHTO, the medial JSW increased at 3 months postoperatively and the lateral JSW decreased immediately. The preoperative and postoperative JLCAs and the medial femoral and tibial cartilage grades were associated with the change in the medial JSW. However, no significant parameters were associated with the decrease in the lateral JSW.Level IV, case series of therapeutic study.

Purpose To verify whether lateral hinge fracture (LHF) affects correction accuracy in open-wedge high tibial osteotomy (OWHTO) and to identify the fracture characteristics responsible for inaccurate correction, including LHF type and hinge location. Methods Patients undergoing OWHTO with locking plate fixation between 2010 and 2016 were retrospectively reviewed. Patients who did not have a minimum 2-year of follow-up or postoperative long-standing hip-to-ankle radiographs were excluded. Correction accuracy was assessed using the weight-bearing line ratio: 57% to 67%, planned correction; 50% to 70%, acceptable correction; otherwise, inappropriate correction. The association between LHF and correction accuracy was assessed using the χ2 test. To identify the fracture characteristics responsible for inaccurate correction, LHF type (stable type 1 and unstable types 2 and 3) and hinge location (shallow osteotomy, deep osteotomy, and occult complete osteotomy) were analyzed using ordinal logistic regression analysis, taking other related demographic and radiologic factors into account. Clinical outcomes according to LHF type were evaluated using the Hospital for Special Surgery scores. Results A total of 148 cases were included; 41 (27.7%) showed LHF: type 1, 32 cases; type 2, 7 cases; and type 3, 2 cases. Planned, acceptable, and inappropriate corrections were noted in 63 (42.6%), 36 (24.3%), and 48 (32.4%) cases, respectively. LHF had a significant association with correction accuracy (P = .010). Regarding fracture characteristics, unstable LHF and occult complete osteotomy were significant risk factors (P = .016 and P = .004, respectively). Specifically in cases of stable LHF, occult complete osteotomy adversely affected correction accuracy (P = .025). No difference was found in the final Hospital for Special Surgery scores according to LHF type (P = .816). Conclusions LHF affected the accuracy of coronal alignment correction in OWHTO. Unstable LHF or occult complete osteotomy were risk factors for inaccurate correction. Even among stable LHFs, those with occult complete osteotomy could lead to inaccurate correction. Level of Evidence Level III, retrospective cohort study.

This study analyzes the large number of lateral meniscal allograft transplantation (LMAT) procedures conducted by a single surgeon over 23 years to determine whether the absolute amount of graft subluxation and the incidence of extrusion are different at the present time compared to the early MAT era.We reviewed 320 cases of LMAT performed by a single surgeon between 1996 and 2019. This cohort was chronologically divided into 8 groups (of 40 subjects). The absolute amount of subluxation was measured by the coronal sections of magnetic resonance images taken 1 year after operation. Subluxation by more than 3 mm was considered as extrusion. The graft extrusion learning curve was plotted in each series using the learning curve cumulative summation test (LC-CUSUM).Extrusion incidence was 41.6%, and the mean absolute amount of graft subluxation was 3.4 ± 2.2 mm for all subjects. There were significant between-group differences in extrusion incidence and absolute amount of graft subluxation (extrusion incidence, P.001; absolute amount of graft subluxation, P.001), and the extension incidence and graft subluxation decreased from Group I (72.5%, 4.6 ± 1.7) to Group VIII (27.5%, 2.5 ± 2.1). LC-CUSUM analysis signaled that the surgeon had achieved predefined acceptable outcomes in avoiding extrusion after 128 cases.The incidence of extrusion and absolute amount of graft subluxation decreased significantly over a period of 23 years, and the surgeon achieved a certain level of proficiency after 128 cases.Level IV, Case series.

Background: Data are lacking regarding the survival rate after medial meniscal allograft transplantation (MAT) alone. Furthermore, little information is available about prognostic factors for graft survival that affect the outcomes of medial MAT. Purpose: To investigate the prognostic factors and survival rate of allograft after medial MAT. Study Design: Case-control study; Level of evidence, 3. Methods: The records of 78 consecutive patients who underwent primary medial MAT between 1996 and 2018 were reviewed. Kaplan-Meier survival analysis was performed to analyze the anatomic and clinical survival rates. Anatomic failure was defined as a tear covering >50% of the allograft or unstable peripheral rim. Clinical failure was considered Lysholm score 50% of the allograft. Patient factors affecting anatomic and clinical failure were analyzed. Results: The mean follow-up period was 6.9 ± 5.3 years (range, 2-21 years). Anatomic failure was noted in 19 patients (24.4%), and none of these patients had a persistent poor Lysholm score of Conclusion: Low-grade ICRS lesion was associated with higher anatomic survival rate after medial MAT. In patients with high-grade ICRS lesions, the clinical outcome might be good; however, the status of an allograft might be poor. The surgeon should be aware of this and explain to the patient that close observation is necessary.

BACKGROUND AND OBJECTIVES Patients who undergo total knee arthroplasty (TKA) have a risk of postoperative anaemia. This observational study evaluated whether single-dose intravenous ferric carboxymaltose (FCM) administered immediately after TKA facilitates the correction of anaemia. MATERIALS AND METHODS We retrospectively analysed 722 patients who underwent primary TKA. The FCM group receiving 1000 mg intravenous FCM within one postoperative hour was compared with the non-FCM group that did not receive the medication. A propensity score matching with multiple logistic regression analysis was used to minimize intergroup differences in the baseline characteristics and postoperative blood loss. The rate and severity of postoperative anaemia were compared between the groups, along with haemoglobin (Hb) value, transfusion rate and complications. RESULTS After propensity score matching, 231 patients were included in each group. In the FCM group, the rate of anaemia at postoperative day (POD) 7 (p = 0.021) and postoperative week (POW) 5 (p

Background: Whether lateral hinge fracture (LHF) after open-wedge high tibial osteotomy (OWHTO) is associated with the change in tibial posterior slope (PS) has not been determined. Risk factors for PS increase are still unknown. Hypothesis: There will be no difference in patient characteristics and radiographic factors when stratified by change in tibial PS (ΔPS). Study Design: Cohort study; Level of evidence, 3. Methods: We reviewed the records of 148 patients who underwent OWHTO with locking-plate fixation from 2010 to 2016. Included were those with a minimum 2-year follow-up and true lateral radiographs before and at 1 year after surgery. ΔPS was defined as a difference between preoperative and 1-year postoperative PS, with positive values indicating PS increase. ΔPS was classified into Results: There were 79 (53.4%) patients with ΔPS Conclusion: LHF type and correction angle were associated with ΔPS after OWHTO, and unstable LHF and large correction angle were risk factors for PS increase. There was no significant difference in clinical outcomes according to ΔPS.

(1) To investigate whether patients with bone-on-bone (BOB) medial OA (Ahlback grade 2) had comparable clinical improvement to those with non-BOB arthritis with remaining joint space (Ahlback grades 0/1) after medial open-wedge high tibial osteotomy (MOWHTO); (2) to determine whether the radiological results differ between these 2 groups from 1 month postoperatively to last follow-up ≥2 years later.Data of 132 knees (40 males and 92 females) who underwent MOWHTO were retrospectively reviewed. Preoperative standing anteroposterior radiographs were evaluated according to the Ahlback classification. Patients with Ahlback grade ≤1 were classified as the non-BOB group (group I, n = 88; mean age, 50.5 ± 6.3 years) and those with grade 2 as the bone-on-bone group (group II, n = 44; age, 51.6 ± 5.3 years). Clinical outcomes were assessed using Hospital for Special Surgery (HSS) and Knee Society (KS) functional scores. Medial joint space width (JSW), medial proximal tibial angle (MPTA), and mechanical alignment were considered radiological parameters.Preoperative clinical scores were significantly lower in patients with BOB arthritis (HSS score: group I, 73.5 ± 10.7 versus group II, 69.2 ± 9.1, P = .026; KS score: group I, 72.9 ± 10.3 versus group II, 63.2 ± 11.6 points, P.001). However, HSS and KS functional scores improved in both groups without a significant difference at a mean follow-up of 3.4 ± 2.5 and 4.1 ± 3.1 years in groups I and II, respectively (HSS score: 89.2 ± 9.5 versus 89.4 ± 7.3 points, P = .258; KS functional score: 90.1 ± 7.1 versus 87.8 ± 8.9 points, P = .105). Preoperative and postoperative medial JSWs were narrower in group II, but the JSW opening was wider in group II at 1 month after surgery and was maintained until the last follow-up (preoperative, 3.0 ± 0.9 versus 0.0 ± 0.1 mm; 1 month, 3.1 ± 1.0 versus 1.4 ± 0.8; last follow-up, 3.0 ± 1.0 versus 1.4 ± 0.9 mm; P.001).Patients with BOB medial OA achieved clinical outcomes comparable to those with remaining joint space after MOWHTO. The medial JSW showed a significant increase without OA progression during midterm follow-up in these patients. Therefore, MOWHTO can be an effective treatment choice for symptomatic improvement in middle-aged patients with severe medial OA, if there is no subchondral bone attrition.III, retrospective comparative study.

Purpose To compare the differences with respect to clinical and graft survivorship and patient-reported outcomes (PROs) between lateral (LMAT) and medial (MMAT) meniscus allograft transplantation. Methods Patients having a primary MAT between 1998 and 2016 were enrolled. The inclusion criteria were (1) patients who had a minimum 2-year follow-up and (2) patients who had magnetic resonance imaging (MRI) >2 years after surgery. Knees with localized grade 4 articular cartilage lesions >3 cm2 at the time of MAT were excluded. Clinical failure was defined as follows: modified Lysholm score 50% of the graft, meniscectomy to the meniscocapsular junction zone, conversion to revision MAT, or realignment osteotomy or arthroplasty. Graft failure was defined as follows: tears involving >50% of the graft or unhealed peripheral rim observed on MRI. Kaplan–Meier survival analysis with log-rank test was used to compare survivorship between LMAT and MMAT. Patient-reported outcomes were compared based on the Hospital for Special Surgery, modified Lysholm, and International Knee Documentation Committee subjective scores collected preoperatively and at the final follow-up. Results A total of 299 knees (249 LMAT, 50 MMAT, mean age 33.0 ± 9.8 years) were included. Twenty clinical [2 MMAT (4.0%), 18 LMAT (7.2%)] and 24 graft [2 MMAT (4.0%), 22 LMAT (8.8%)] failures were identified. The mean clinical follow-up period was 63.1 ± 43.1 months (range 2 to 248), and MRI follow-up period was 62.6 ± 43.8 months (range 2 to 248). No significant differences in clinical and graft survivorship were found between the LMAT and MMAT groups (P = .481, P = .271, respectively). PROs preoperatively and at last follow-up also showed no significant difference between the groups. Conclusion No significant differences in clinical survivorship, graft survivorship, and PROs were found between the LMAT and MMAT groups. Level of evidence Level III, retrospective comparative study.

This study aimed to assess the cartilage status in patients who underwent isolated lateral meniscus allograft transplantation (MAT) using preoperative and postoperative quantitative 3-T magnetic resonance imaging (MRI) T2 mapping at midterm follow-up period.Patients who underwent lateral MAT without cartilage treatment procedures between 2010 and 2019 were assessed by quantitative MRI preoperatively and postoperatively. On the sagittal section image following the center of the lateral femoral condyle, the weightbearing area of the articular cartilage was divided into six segments based on the meniscal coverage area from anterior to posterior direction. The mean T2 values of each six segments were measured for three regions of interest: overall, deep, and superficial layers. The change in T2 values was statistically analyzed by paired t-tests. The Lysholm score was used to evaluate clinical function.A total of 105 patients were included in the study. The mean follow-up period was 3.2 years (range, 2.0-5.4 years). Among the six segments, the mean T2 value showed significant improvement in the overall layer of F2 (the middle weightbearing area of femoral condyle) and TP3 (the posterior weightbearing area of tibia condyle) segments (P = .013 and .021, respectively) and the superficial layer of the F3 (the posterior weightbearing area of femoral condyle) segments (P = .028). The mean T2 value of all the other segments did not show statistically significant change. The mean Lysholm score significantly improved from 66.5±15.8 to 89.3±10.0 (P.001). Overall, 73.3% and 96.2% of the patients met MCID and PASS respectively.The mean T2 value of the articular cartilage of the weightbearing area was either maintained or showed statistically significant improvement depending on the location following isolated lateral MAT. Thus, the transplanted meniscus seems to have the chondroprotective effect on the weightbearing cartilage.Level IV, retrospective therapeutic case series.

Background:Although joint-line obliquity (JLO) after open-wedge high tibial osteotomy (OWHTO) is commonly encountered, especially in cases of overcorrection, its effect has not been fully elucidated or has been assessed only in the short term. The acceptable range of JLO, often recognized as ≤4°, has not been determined as per the midterm outcomes of OWHTO.Hypothesis:Joint-line obliquity exceeding the acceptable limit after OWHTO would accelerate cartilage degeneration and adversely affect midterm clinical outcomes.Study Design:Cohort study; Level of evidence, 3.Methods:A total of 109 patients who underwent OWHTO between 2010 and 2015 with a mean follow-up period of 55.0 months (range, 24-102 months) were reviewed. JLO was defined as the angle between the lines parallel to the floor and to the tibial plateau on a long-standing hip-to-ankle radiograph. For radiologic evaluation according to JLO, the medial joint space width (JSW) was measured on a standing 45° flexion posteroanterior view and standardized with the width of the tibial plateau as reference, after which changes in JSW (ΔJSW) between the 6- and 12-month postoperative period and the latest follow-up were calculated. ΔJSW was analyzed according to 2 different cutoff values of JLO: JLO of 4°, which is currently recognized as the acceptable limit, and that derived from the receiver operating characteristic (ROC) curve for the third quartile of ΔJSW. Multivariate regression analysis including JLO as well as other demographic and radiologic factors was performed. Clinical outcomes were evaluated in the same way using Knee Society (KS) objective and functional scores.Results:With a JLO cutoff of 4° in the multivariate regression analysis, JLO was not significantly associated with ΔJSW ( P = .545). However, in the KS objective and functional score analyses, JLO ≥4° was found to be a significant factor ( P = .045 and .005, respectively). The ROC curve showed a cutoff JLO of 6°, which was significantly associated with ΔJSW ( P = .001). JLO ≥6° remained significant in the analyses for KS objective and functional score ( P = .012 and .001, respectively).Conclusion:The adverse effect of JLO on radiologic outcomes was shown when JLO was ≥6°. In clinical aspects, worse outcomes were found in cases of JLO ≥4°.

Background Femoral coronal bowing (FCB) has been reported to be a risk factor for mechanical malalignment after total knee arthroplasty (TKA). However, the effects of FCB on the long-term survivorship (when postoperative mechanical alignment (MA) is neutral after TKA) have not been determined. Hypothesis The effects of FCB on the cumulative survivorship after TKA may be significantly smaller compared with those of MA. Patients and methods Consecutive 328 knees of 211 patients (10 males, 201 females) who underwent TKA between 1995 and 2009 (mean age of 64.2 ± 6.7 years at the time of TKA, mean follow-up period of 11.9 ± 2.5 years) were retrospectively evaluated. FCB and MA were evaluated using preoperative and immediate postoperative whole-leg anteroposterior radiographs, respectively. The patients were grouped according to FCB and postoperative MA, which included group A (FCB ≤ 5°, MA ≤ 3°), B (FCB > 5°, MA ≤ 3°), C (FCB > 5°, MA > 3°), and D (FCB ≤ 5°, MA > 3°). Primary end-point was defined as aseptic mechanical failures requiring revision TKA. Survivorship was assessed using the Kaplan-Meier method and compared using log-rank tests. Factors associated with the risk of aseptic mechanical failures were analyzed by Cox regression analysis. Preoperative and final follow-up clinical outcomes were assessed using Hospital for Special Surgery (HSS) scores. Results Group A, B, C, and D included 190, 73, 40, and 25 knees, respectively. The 10-year survivorship was similar between group A and B (96.3 ± 1.4% vs. 98.6 ± 1.4%; p = 0.733) and group C and D (87.3 ± 5.3 vs. 87.6 ± 6.7%; p = 0.974); however, it was significantly higher in group B than in group C (p = 0.036) and in group A than in group D (p = 0.005). Age (OR = 0.991; 95% CI 0.906–1.085; p = 0.002) and MA > 3° (OR = 3.645; 95% CI 1.744–7.604; p = 0.001) were associated with the risk of aseptic mechanical failures. The mean preoperative and final HSS scores in the four groups were not significantly different. Discussion Marked FCB was not associated with long-term survivorship for knees with neutral alignment after TKA. However, non-neutral postoperative alignment reduced long-term survivorship for knees with marked FCB. Level of evidence III, Retrospective comparative cohort study.

Background: Factors associated with graft survival after lateral meniscal allograft transplantation (MAT) have not been fully determined, and survival analysis focused on effect of varus alignment has not been performed. Hypothesis: Varus alignment of the knee leads to better graft survival and clinical outcomes after lateral MAT than normal alignment. Study Design: Cohort study; Level of evidence, 2. Methods: The records of 204 consecutive patients who underwent lateral MAT were reviewed. After exclusion of cases undergoing revision MAT, cases without hip-knee-ankle standing radiographs, and cases with valgus alignment, the patients were categorized into 2 groups, those with normal alignment within −3° to 3° of the mechanical axis and those with varus alignment >3°. Cumulative graft survival rates were compared in the 2 groups before and after controlling for other covariates, including sex, age, body mass index (BMI), time from meniscectomy, the number of accompanying procedures, and cartilage status. Failure was defined as (1) a graft tear involving >50% or unstable peripheral rim of the allograft; (2) a Lysholm score 50% or to the zone of meniscocapsular junction; or (4) conversion to revision MAT, realignment osteotomy, or arthroplasty. Clinical outcomes were compared between the 2 groups by Lysholm score. Results: Of the 190 patients, 149 showed normal alignment of 0.3° ± 1.3° (range, –3° to 3°) and 41 showed varus alignment of 4.8° ± 0.6° (range, 4°-8°). A total of 22 patients (11.6%) experienced MAT failure: 21 patients with normal alignment and 1 with varus alignment. Kaplan-Meier survival analysis showed a significant difference in the cumulative graft survival rates between the 2 groups (log-rank test, P = .001). After controlling for age, sex, BMI, time from meniscectomy, the number of accompanying procedures, and cartilage status, varus alignment was found to be a significant protective factor ( P = .004). On the other hand, there was no difference in clinical improvement measured by the Lysholm score between the 2 groups ( P = .651). Conclusion: Varus alignment was associated with better graft survival after lateral MAT than normal alignment. However, no significant differences in clinical outcomes were observed.

In total knee arthroplasty (TKA) using the intramedullary tibial cutting guide (IMTCG), the positioning of the IMTCG is important for accurate tibial bone resection. The aim of this study was to evaluate the ideal entry point of IMTCG and affecting radiologic factors. From May 2017 to February 2018, 91 consecutive TKAs for osteoarthritis were included. From preoperative full-length radiographs, we measured the medial proximal tibia angle (MPTA), lateral distal tibia angle (LDTA), tibial bowing angle (TBA), medial to lateral width of the tibial plateau, tibial length, and ideal coronal entry point. In preoperative short knee lateral radiographs, we measured the anterior to posterior length of the tibial plateau, tibial posterior slope angle (TPSA), metaphysio-diaphyseal angle (MDA), and ideal sagittal entry point. The ideal coronal and sagittal entry points were defined as the points crossing the tibial plateau and tibial anatomical axis on the coronal and sagittal radiographs, respectively. The ideal entry point was 51.4 ± 4.3% (SD) from the medial margin and 27.0 ± 5.8% (SD) from the anterior margin of the tibial plateau. However, the range varied from 39.8 to 60.5% on the coronal plane and from 9.6 to 37.7% on the sagittal plane, respectively. As the MPTA (rho = − 0.490) and TBA (rho = − 0.433) were increased, the coronal entry point moved medially. As TPSA (rho = − 0.761) and MDA (rho = − 0.495) were increased, the sagittal entry point moved anteriorly. The ideal entry point of IMTCG should vary according to the individual tibial morphology.

Background: Long-term outcomes after lateral meniscal allograft transplantation (MAT) are not completely understood. Purpose/Hypothesis: We investigated changes in meniscal extrusion in the coronal and sagittal planes using magnetic resonance imaging (MRI) after lateral MAT through long-term follow-up. We hypothesized that meniscal extrusion would progress during follow-up. Study Design: Case series; Level of evidence, 4. Methods: Patients subjected to lateral MAT were followed up by MRI evaluation in both planes at 1, 4 to 6, and >8 years after MAT. Meniscal extrusion and entire meniscal widths in the coronal plane and anterior (ACMD) and posterior (PCMD) cartilage meniscal distances in the sagittal plane were measured, and values were compared at each time point. Clinical outcomes were evaluated using the Lysholm score. Results: A total of 27 lateral MATs were included with a mean MRI follow-up period of 10.3 years (range, 8.1-15.3 years). The mean absolute meniscal extrusion (coronal plane) was not significantly different at each time point. However, the relative value differed (0.27 ± 0.04 at 1 year; 0.33 ± 0.06 at >8 years after MAT) owing to entire meniscal width reduction. There was no difference in the mean absolute value of the ACMD in the sagittal plane. However, relative values differed (0.21 ± 0.01 at 1 year; 0.27 ± 0.06 at >8 years) owing to entire meniscal width reduction. Absolute and relative values of the PCMD remained unaffected at each time point. The Lysholm score increased after surgery but did not differ postoperatively. Conclusion: During the long-term follow-up of extrusion after lateral MAT using MRI, absolute extrusion remained unchanged across all planes. Relative extrusion in the coronal plane and of the ACMD in the sagittal plane significantly increased, with no differences in the PCMD on follow-up. Clinical outcomes after surgery improved compared with those before surgery and were maintained throughout the long-term follow-up period.

This study aimed at determining whether overcorrection after open wedge high tibial osteotomy (OWHTO) would be predicted by the magnitude of preoperative medial and lateral coronal soft tissue laxity around the knee joint.Overall, 68 knees of 62 patients who underwent OWHTO for primary medial osteoarthritis were retrospectively reviewed. The mechanical hip-knee-ankle (HKA) axis, weight-bearing line (WBL) ratio, medial proximal tibial angle (MPTA), joint line obliquity, coronal subluxation, and joint line convergence angle (JLCA) were measured on full-weight-bearing long-standing HKA radiographs preoperatively and at 1 year postoperatively. The varus valgus stress angle was measured on preoperative radiographs. The correction amount due to soft tissue factors was calculated as the difference between the WBL ratio on postoperative 1-year radiographs and that on virtually corrected preoperative radiographs with the same amount of MPTA at 1 year postoperatively. The patients were grouped according to the presence or absence of a ≥ 10% overcorrection of WBL ratio (overcorrection or expected correction). Multiple logistic regression analysis was performed to identify the preoperative risk factors of overcorrection.The average WBL ratio was corrected from 19.0 ± 13.5% preoperatively to 61.6 ± 9.1% postoperatively (P 0.001). The average MPTA changed from 85.1 ± 1.7° preoperatively to 93.6 ± 2.6° postoperatively, resulting in an average tibia correction angle of 8.6 ± 3.1°. The average estimated correction from soft tissue factors was 5.8 ± 7.4% of the WBL ratio. Soft tissue correction of the WBL ratio 10% was confirmed in 17 patients (28%). The preoperative JLCA and valgus stress angle were significantly greater in the overcorrection group than in the expected correction group: 5.0 ± 1.7° vs. 3.4 ± 1.9° (P = 0.003) and 2.4 ± 1.0° vs. 1.3 ± 1.2° (P = 0.002), respectively. Among the radiologic parameters, the presence of both ≥ 4° JLCA and ≥ 1.5° valgus stress angle was the only significant risk factor for overcorrection from soft tissue factors (P = 0.006; odds ratio, 30.2).The magnitude of both medial and lateral coronal soft tissue laxity was a predictor of overcorrection from soft tissue factors after OWHTO. Overcorrection was more likely to occur in cases with both ≥ 4° JLCA and ≥ 1.5° valgus stress angle.III.

Introduction Meniscal extrusion is a typical finding of medial meniscus posterior root tear, and it causes loss of the chondroprotective function of the meniscus as well as progression of osteoarthritis; it is therefore associated with poor clinical outcomes. The purpose of this study was to investigate factors associated with meniscal extrusion in degenerative medial meniscus posterior root tear. It was hypothesized that larger displacement from the posterior root insertion was associated with larger meniscal extrusion. Materials and methods One hundred and nine knees with degenerative medial meniscus posterior root tears were retrospectively reviewed. Multiple regression analysis was used to determine whether factors such as age, weight, body mass index, chondral wear at surgery, Kellgren-Lawrence (KL) grade, alignment, tibial slope, and tear gap on performing magnetic resonance imaging (MRI) were associated with meniscal extrusion. Subjects were divided based on the amount of displacement (displaced group: tear gap ≥ 1 mm, non-displaced group: tear gap Results The mean age of the patients was 58.14 ± 9.64 years, the mean absolute extrusion was 4.02 ± 1.22 mm, the mean relative percentage of extrusion was 44.53 ± 13.09%, and the mean tear gap was 2.39 ± 2.42 mm. Multiple regression analysis showed that absolute extrusion was only associated with tear gap on MRI (B = 0.242, p = 0.001) and that the relative percentage of extrusion was associated with tear gap (B = 1.894, p = 0.001) and the K-L grade (B = 4.492, p = 0.024). Absolute extrusion was significantly higher in the displaced group than in the non-displaced group (4.29 ± 1.04 mm vs. 3.01 ± 1.35 mm, p = 0.001). Relative percentage of extrusion was also significantly higher in the displaced group than in the non-displaced group (47.70 ± 11.44% vs. 36.17 ± 13.65%, p = 0.001). The proportion of chondral wear (Outerbridge grade III and IV) on the medial femoral condyle and K-L grade III and IV were significantly greater in the displaced group than in the non-displaced group (76% vs. 53.3%, p = 0.023 and 13.9% vs. 0%, p = 0.001, respectively). Discussion Greater tear gap is significantly associated with increasing meniscal extrusion in medial meniscus posterior root tear. Additionally, severity of arthritis is significantly associated with increasing relative percentage of extrusion. Chondral wear and severity of arthritis tended to be significantly worse in the displaced group than in the non-displaced group. Level of evidence III, comparative retrospective study.

BACKGROUND The discoid lateral meniscus (DLM) in children often presents peripheral rim instability (PRI) and is susceptible to tear or subluxation, which manifests symptoms and leads to a poor prognosis. We aimed to investigate the association between preoperative clinical and MRI findings and the intraoperative findings of PRI. METHODS Children and adolescents aged younger than 16 years who underwent surgical treatment for DLM were retrospectively reviewed. Cases of bucket-handle tear were not included because they would confound the stability of the peripheral rim. Total 60 knees from 47 children were included. PRI was additionally subdivided based on the location, such as anterior, middle, and posterior, during the investigation. RESULTS In multivariate analyses, both central (inward) (P=0.004) and external (outward) (P=0.029) displacement of lateral meniscal margin, and peripheral tear of the anterior body (P=0.022) were significant predictors of PRI, regardless of the location. The predictive factors for PRI based on each location were female gender (P=0.004), subjective symptom of clicking sound (P=0.023), and central displacement of the anterior meniscal margin (P=0.034) for anterior PRI; flexion contracture >10 degrees (P=0.017) and peripheral tear of the middle body (P

Purpose To evaluate the incidence and degree of shrinkage of transplanted fresh-frozen meniscal allografts in a long-term period of >8 years and to investigate whether the shrinkage of allograft progresses and is associated with inferior clinical and radiologic outcomes after meniscal allograft transplantation (MAT) in the long term. Methods Twenty-two knees were reviewed in 20 patients (mean age, 31.41 ± 9.11 years) who underwent isolated lateral MAT. All patients were followed with magnetic resonance imaging (MRI) for at least 8 years (mean, 11.78 ± 3.10 years). The allograft widths of the anterior horn, mid-body, and posterior horn at 1 and >8 years postoperatively were measured by using MRI. To estimate the degree of shrinkage, the relative changes in widths during intervals were calculated. Patients were categorized into 4 groups according to shrinkage degree: minimal ( 50%). The joint space width was measured on the weightbearing radiographs to evaluate the radiologic outcome. The Lysholm score was used to evaluate the clinical outcome. Results The relative change in the width of the anterior horn, mid-body, and posterior horn, compared with that 1 year postoperatively, was 82.7% (95% confidence interval 77.4%-87.5%), 75.9% (70.7%-81.0%), and 85.0% (81.4%-88.5%), respectively. The shrinkage degree was greater at the mid-body than at the anterior and posterior horns. About 70% of allografts showed ≥10% shrinkage of the posterior horn. Meniscal shrinkage did not show significant correlation with clinical and radiologic outcome. Conclusions At long-term follow-up (>8 years), shrinkage of transplanted fresh-frozen meniscal allografts progressed at 1 year postoperative. On average, the shrinkage was mild and more prominent in the mid-body than in the anterior or posterior horn. In this study, it could not be concluded that the shrinkage of allografts was significantly associated with inferior clinical and radiologic outcomes in the long term. Level of Evidence Level IV, therapeutic case series.

Preoperative varus deformity may affect postoperative mechanical alignment and outcomes of total knee arthroplasty (TKA). In this study, we aimed to determine whether (1) greater degrees of preoperative varus deformity increase the incidence of varus-aligned TKAs and (2) residual varus alignment improves the long-term survival rate in TKAs with preoperative varus deformity.We retrospectively reviewed 905 primary TKAs for varus-type osteoarthritis from November 1998 to June 2009. The mean follow-up was 8.23 years (±3.47 years). We measured pre- and postoperative mechanical hip-knee-ankle axis angle (HKA) on full-length standing radiographs to assess the severity of preoperative varus deformities, defined as mild (0°HKA≤5°), moderate (5°HKA≤10°), severe (10°HKA≤15°), and very severe (HKA15°). Postoperative alignment was divided to four groups: valgus (HKA-3°), neutral (-3°≤HKA≤3°), mild varus (3°HKA≤6°), and severe varus (HKA6°). We performed survival analysis in all cases for mechanical failure.Varus-aligned TKAs increased proportionally to increasing preoperative varus deformity (p0.001). The survival rate showed no significant difference according to the preoperative varus deformity (p=0.147). However, the survival time for postoperative neutral alignment (16.13±0.10 years, 95% CI 15.94-16.33 years) was longer than the survival time for mild varus (15.32±0.35 years, 95% CI 14.64-16.00 years) and severe varus (13.38±0.53 years, 95% CI 12.35-14.42 years) alignment (p0.001).Postoperative varus malalignment appears to increase proportionally to the severity of preoperative varus deformity. Also, postoperative neutral alignment results in longer TKA survival time than residual varus alignment.III, Retrospective comparative cohort study.

To evaluate the effect of age itself on the joint survivorship after arthroscopic partial meniscectomy (APM) for degenerative medial meniscus tears (DMTs).Patients undergoing APM for DMTs during 1999-2010 were retrospectively reviewed. The inclusion criteria were as follows: (1) DMTs identified on preoperative MRI scans, (2) no definite history of trauma, and (3) follow-up duration more than 5 years. In evaluation of the joint survivorship, the endpoint was defined as conversion to arthroplasty (or realignment osteotomy) or progression to Kellgren-Lawrence grade 4. The study population was divided into older and younger groups by a cutoff age at which the difference in the joint survival rates was maximized, using a time-dependent receiver operating characteristic (ROC) curve. The two groups were then matched based on propensity scores. The joint survival rates were compared between the groups using Kaplan-Meier analysis, before and after propensity score matching (PSM).A total of 633 knees were included. The cutoff age was calculated as 60 years. Before PSM, 239 knees were allocated to the older group (≥ 60 years) and 394 knees to the younger group ( 60 years). A significant difference in the joint survival rates was noted between the groups (log-rank test, p 0.001). After PSM, 183 knees remained in each group. The difference in the survival rates was no more statistically significant (n.s.). The latest Lysholm scores of the older and the younger groups before PSM were 72.2 ± 20.8 and 79.9 ± 19.6, respectively (p 0.001); however, the scores after PSM were 73.2 ± 20.3 and 77.4 ± 20.5, respectively (n.s.).Joint survivorship after APM was affected by other factors associated with the aging process, such as cartilage status and meniscal tear pattern, rather than age itself. Advanced age should not be the only reason for precluding APM in treatment of DMTs. APM is a viable option when treating DMTs in elderly patients if adopted with caution. According to this study, a surgeon should assess the age-related factors when he considers APM in elderly patients.III.

Staggered bilateral total knee arthroplasty, two procedures performed 4-7 days apart during a single hospitalization, has an increased risk of blood transfusion. This observational study aimed to evaluate whether immediate post-operative single, high-dose intravenous iron supplementation could reduce transfusion requirements and facilitate anaemia recovery in patients.We retrospectively analysed 131 patients who underwent staggered bilateral total knee arthroplasty. The ferric carboxymaltose (FCM) group received 1000 mg of FCM after the first operation. The non-FCM group did not receive intravenous iron. The transfusion rate and post-operative complications were compared between the groups. The anaemia rate was evaluated pre-operatively, during hospitalization, and 5 weeks after the second total knee arthroplasty.The FCM group comprised 78 patients (59.5%). The rate (21.8% vs. 47.2%, p = 0.004) and amount of transfusion (0 [0-2] vs. 0 [0-0], p = 0.001) was significantly lower in the FCM group than in the non-FCM group. Although both groups' pre-operative haemoglobin concentrations were not significantly different, the FCM group demonstrated higher haemoglobin values 5 weeks post surgery (12.25 ± 0.83 mg/dl vs. 11.48 ± 1.36 mg/dl, p 0.001). More non-FCM patients developed moderate to severe anaemia at 5 weeks post surgery (p 0.001). The mortality and complication rates were not significantly different.Immediate post-operative, high-dose, intravenous iron treatment may contribute to reduced transfusion rates, facilitate haemoglobin recovery after staggered bilateral total knee arthroplasty, and minimize the development of moderate to severe anaemia.

Background: Magnetic resonance imaging (MRI) is an effective tool for objective evaluation after meniscal allograft transplant (MAT). Little is known about the association between MRI features of allograft and clinical outcomes. Purpose/Hypothesis: To assess the degree and location of signal intensity (SI) as well as the morphology of allografts on MRI after MAT and evaluate the association between clinical outcomes and MRI features in the midterm period. It was hypothesized that a high SI accompanied by a deformed allograft in specific locations on MRI would be associated with inferior clinical outcomes. Study Design: Cohort study; Level of evidence, 3. Methods: Included were patients who underwent MAT with fresh-frozen allografts and had >3 years of follow-up with 3.0-T MRI scans. Allograft status was assessed by SI on MRI as grade 0 (normal), grade 1 (globular increased SI not adjacent to the articular surface), grade 2 (linear SI within the meniscus), or grade 3 (increased SI extended to the articular surface). Allograft morphology was assessed by the presence of distorted contours. Clinical outcomes were evaluated using the Lysholm score. The association between clinical outcomes and MRI findings was assessed by multiple linear regression analysis. Results: A total of 138 patients (156 MAT procedures: 132 lateral, 24 medial) with a mean follow-up period of 55.4 ± 19.9 months (range, 36-110 months) were enrolled in this study. Grade 3 SI was observed in the posterior meniscus root and posterior third of the allograft in 39 (25%) and 62 (39.7%) MATs, respectively. Among the 62 MATs with grade 3 SI in the posterior third of the allograft, 34 (54.8%) were accompanied by distorted allograft contour. The presence of grade 3 SI with distorted contour in the posterior third of the allograft was significantly associated with inferior outcomes (β = –6.5 [95% CI, –12.5 to –0.5]; P < .035), as was the presence of grade 3 SI in the posterior meniscus root (β = –5.5 [95% CI, –10.5 to –0.4]; P < .034). Conclusion: On MRI evaluation in the midterm period after MAT, grade 3 SIs of the meniscal allograft were observed in about a third of the cases, and the association with clinical outcomes was dependent on the specific location and morphology of the allograft on MRI.

This study aimed to evaluate graft survivorship according to the size and location of chondral defects and its effect on clinical outcomes after meniscal allograft transplantation (MAT). It was hypothesized that large chondral defects would be associated with inferior outcomes. Patients who underwent lateral MAT with fresh-frozen allografts between 2007 and 2016 were retrospectively reviewed. The inclusion criteria were patients with femoral or tibial chondral defects (International Cartilage Repair Society grade 4) who were followed up more than 2 years with 3.0-T magnetic resonance imaging (MRI) scans. Maximal lesion diameter and location were assessed on MRI. The patients were divided into two groups, with chondral defects of

Background:Lateral hinge fracture (LHF) after medial open wedge high tibial osteotomy (MOWHTO) may not be recognized on perioperative plain radiographs. Such cases may be identified at follow-up and misdiagnosed as delayed LHF.Purpose:This study aimed to investigate the extent of LHF misdiagnosis and to determine whether patients with LHFs have inferior clinical outcomes after MOWHTO.Study Design:Case series; Level of evidence, 4.Methods:Fifty-one knees in 50 patients (36 women, 14 men; mean age, 51.8 years; range, 24-64 years) who had undergone MOWHTO with locking plate fixation between October 2013 and April 2016 were retrospectively reviewed. LHFs identified on intraoperative fluoroscopy and immediate postoperative radiographs were compared with the actual incidence based on computed tomography (CT) scans performed within 2 days of surgery. Delayed LHFs, not visible on the CT scans but found on later follow-up radiographs, were also assessed. More frequent radiographic check-ups were recommended in patients with LHFs, and weightbearing was delayed until evident callus formation was seen on follow-up radiographs for type 2 or 3 fractures. The loss of correction, the time of union, and complication rate were compared between the knees with LHF and those without LHF. Clinical outcome was measured according to the Knee Society (KS) scores.Results:Overall, 14 early LHFs (27.5%) were identified on CT scans. Of these, 7 LHFs (13.7%) were observed on perioperative radiographs, and the remaining 7 LHFs were identified on later radiographs. Delayed LHFs occurred in 2 cases (3.9%). In the 16 knees with LHF, minimal loss of correction was observed 1 month to 1 year postoperatively without statistical significance. No alignment changes were seen in the 35 knees without LHFs. In the LHF versus no LHF groups, no significant differences were seen regarding time of union (5.3 ± 1.7 months vs 5.4 ± 1.8 months, respectively; P = .898) and postoperative KS scores (knee score, 96.6 ± 2.5 vs 95.3 ± 6.4, P = .435; functional score, 94.4 ± 9.6 vs 89.1 ± 10.9, P = .107). No other complications occurred in either group.Conclusion:Most LHFs after MOWHTO occurred intraoperatively, but half (7/14) were not identified on postoperative radiographs. CT scans would enable detection of early LHFs that would otherwise have been mistaken for delayed LHF. However, clinical outcomes did not differ between patients with and without LHF.

Background: Arthroscopic meniscectomy has been commonly performed for persistent pain caused by degenerative medial meniscal posterior root tears (MMPRTs). However, risk factors that affect long-term outcomes and joint survivorship after meniscectomy are unclear. Purpose: To identify the risk factors associated with end-stage osteoarthritis after arthroscopic meniscectomy for degenerative MMPRT for middle-aged or elderly patients and to determine the joint survivorship according to the identified risk factors. Study Design: Case-control study; Level of evidence, 3. Methods: Data from 288 patients (24 male and 264 female), followed for at least 5 years after arthroscopic meniscectomy for degenerative MMPRTs performed between 1999 and 2010, were examined retrospectively. The modified Lysholm score was used for clinical evaluation. Cox proportional hazards regression analysis was used to assess factors that affect joint survivorship when conversion to total knee arthroplasty (TKA) was taken as the endpoint; these factors were age, sex, body mass index (BMI), preoperative tibiofemoral alignment (varus [Results: Mean age at the time of surgery was 58.9 years (range, 43-78 years). Sixty (20.8%) patients underwent TKA at 7.0 ± 3.6 years (range, 1.1-14.4 years) postoperatively. The mean follow-up time for those who did not undergo TKA was 8.9 ± 2.9 years (range, 4.5-16.5 years). The overall modified Lysholm score improved from 64.4 to 81.3 ( P < .001), but progression of radiographic arthritis was noted in 156 (61.9%) patients ( P < .001) at 2 years postoperatively. Age (hazard ratio [HR] = 1.049), BMI (HR = 1.092), varus alignment (HR = 2.283), and Kellgren-Lawrence grade 2 or higher (HR = 2.960) were significant risk factors for end-stage arthritis requiring TKA. Well-aligned nonarthritic knees (n = 131, 45.5%) survived significantly longer before requiring TKA than did knees with varus alignment or radiographic arthritis ( P < .05). The 5- and 10-year survival rates in these low-risk groups were 97.7% (95% CI, 95.2%-100.2%) and 89.1% (95% CI, 82.4%-95.8%), respectively. Conclusion: Arthroscopic meniscectomy is an effective treatment for degenerative MMPRTs, with favorable long-term survival in well-aligned nonarthritic knees. However, meniscectomy should be undertaken cautiously in patients with varus alignment and preoperative radiographic osteoarthritis.

Background Given that medial open wedge high tibial osteotomy (OWHTO) not only delays the progression of osteoarthritis but also alleviates the resulting pain, surgical outcomes would be improved if limited ROM can also be managed. In this regard, the effect of concurrent notchplasty on flexion contracture has not been evaluated. Hypothesis (1) Concurrent notchplasty in OWHTO would relieve flexion contracture regardless of the severity of osteoarthritis and this effect would be maintained over time, and (2) concurrent notchplasty would not cause any added complications compared to the same procedure without notchplasty. Patients and methods In total, 107 patients who underwent OWHTO between 2011 and 2017 with a mean follow-up period of 46.6 months (range, 24–102 months) were reviewed. ROM was measured at three time points as follows: before surgery, at 6–12 months postoperatively, and at the latest follow-up. The measurements were analyzed using a linear mixed model in terms of notchplasty and other factors, including age, sex, body mass index, preoperative hip-knee-ankle angle, lateral distal femoral angle, medial proximal tibial angle, correction angle, concurrent meniscectomy, postoperative posterior slope, and Kellgren-Lawrence grade. Then, ROMs at the three time points were compared between the notchplasty and non-notchplasty groups. Results Of the 107 patients, 47 underwent concurrent notchplasty. The linear mixed model regarding flexion contracture showed a significant notchplasty-by-time interaction (p Conclusion The preoperative difference in flexion contracture was overcome by adding notchplasty to OWHTO, and this improvement was maintained over time. No added complications were noted in the notchplasty group. The results should be interpreted with caution, considering measurement error of ROM. However, concurrent notchplasty in OWHTO deserves further study to validate its efficacy. Level of evidence III, retrospective cohort study.

Clinical results of meniscal allograft transplantation (MAT) are not always consistent with graft status. This study aimed to investigate (1) the degree and pattern of mismatch between anatomic and clinical failures in MAT and (2) preoperative factors associated with the mismatch.Two hundred and ninety-eight consecutive patients who underwent primary medial or lateral MAT during 2004-2015 were reviewed. Anatomic failure was defined as an allograft showing meniscal tear involving 50% of the graft or unstable peripheral rim. Clinical failure included poor Lysholm score of 65 and any requirement for re-operations such as arthroplasty, realignment osteotomy, revision MAT, and meniscectomy (more than 50% of the graft or to the zone of meniscocapsular junction). Failure cases were categorised according to the type of failure as follows: (1) type 1, anatomic failure followed by clinical failure; (2) type 2, anatomic failure did not lead to clinical failure; and (3) type 3, clinical failure without anatomic failure. Preoperative factors including age, sex, body mass index, MAT compartment, time from previous meniscectomy, alignment, cartilage status, and accompanying procedures were analysed according to the failure type.Forty (13.4%) patients showed anatomical or clinical failure during the median (25th-75th percentile) follow-up duration of 47 (30-72) months (range 24-178 months). Eleven (3.7%) patients showed both anatomical and clinical failure (type 1 failure). Seventeen (5.7%) patients showed anatomic failure that did not lead to clinical failure (type 2 failure). Twelve (4.0%) patients failed clinically without meniscal tear ( 50% of graft) or unstable peripheral rim (type 3 failure). Comparative analyses among failure types found a significant difference in MAT compartment (p = 0.01). In particular, the incidence of type 3 failure was higher in medial than in lateral MAT (p = 0.003).A notable number of failure cases of MAT showed a mismatch between anatomic and clinical failures. Even with anatomic failure, MAT did not always lead to poor clinical scores or re-operations, whereas MAT could have poor results without substantial allograft problems. Therefore, both anatomic and clinical aspects should be considered when evaluating MAT. In particular, type 3 failure occurred more frequently in medial than in lateral MAT.III.

To assess serial changes of limb alignment after open wedge high tibial osteotomy (HTO) using the weightbearing line (WBL) ratio in the midterm, with a focus on varus recurrence.Patients undergoing open wedge HTO from January 2010 to December 2016 were retrospectively reviewed. Those without serial postoperative weightbearing long-leg alignment films, those who showed remained varus alignment after osteotomy, and those who had2 years of follow-up were excluded. In terms of immediate postoperative limb alignment (≤3 months) measured using WBL ratio, cases were categorized into 4 groups:50%, undercorrection; 50% to 57%, insufficient correction; 57% to 67%, planned correction; and67%, overcorrection. To determine risk factors for varus recurrence (WBL ratio50%), immediate postoperative WBL ratio category and preoperative valgus and varus stress angles (which represent medial and lateral tightness of the joint, respectively) were investigated using logistic regression analysis, taking other related factors into account. Clinical outcomes according to varus recurrence were measured using Hospital for Special Surgery (HSS) scores.A total of 148 cases were included. Varus recurrence was noted in 40 cases (27.0%), with a mean follow-up of 49.7 ± 21.8 months (range 24 to 102 months). The incidence of varus recurrence was different according to WBL ratio category: 10/10 (100.0%) in undercorrection; 16/33 (48.5%) in insufficient correction; 13/58 (22.4%) in planned correction; and 1/47 (2.1%) in overcorrection. Based on logistic regression analysis, insufficient correction and preoperative valgus stress angle were found to be significant risk factors (P = .038, and .008, respectively). With valgus stress angle2°, 7 of 10 insufficient correction cases showed varus recurrence (P = .005). However, HSS scores did not differ according to varus recurrence (P = .363).Insufficient correction and preoperative medial tightness increased the risk of varus recurrence. Especially in cases where preoperative valgus stress angle was2°, insufficient correction was strongly associated with varus recurrence. However, no significant differences in clinical outcomes were observed according to varus recurrence in the midterm.III, retrospective cohort study.

Meniscal allograft transplantation (MAT) is an effective treatment for patients with symptomatic meniscus-deficient knee after total or subtotal meniscectomy. Since Milachowski performed the first MAT in 1984, there have been many advances in indications, graft selection, and surgical techniques over 30 years and satisfactory long-term clinical results have been reported. Therefore, MAT is now no longer considered an experimental procedure. Thus, it is important to understand indications, surgical techniques, results, and complications of MAT to achieve successful long-term joint preservation in young patients.

Background To the best of our knowledge, there have been no large case studies on patellar fracture after total knee arthroplasty (TKA) with patella retention. Methods From 2005 to 2019, 2954 consecutive TKAs with patella retention were retrospectively reviewed. The incidence of patellar fracture was confirmed. Perioperative demographic factors associated with patellar fracture were compared between the nonpatellar fracture control (randomly selected after age and sex matching) and patellar fracture patient groups. To confirm the prognosis of identified patellar fractures, Hospital for Special Surgery knee score, union rates, and complications after treatment were evaluated. Treatment outcomes were compared as per the treatment method, and fracture type was classified by shape. Results For primary TKAs with patella retention, patellar fracture occurred in 32 of 2883 cases (incidence 1.11%). When comparing the preoperative demographic factors between the patellar fracture and control groups, there was a significant difference in knee flexion of the affected limb. Twenty-three cases were treated nonoperatively, and nine cases were treated operatively. Of the 32 patellar fractures, 28 had confirmed union, and the HSS score at the latest follow-up increased significantly from the preoperative score. The only complication noted after treatment was nonunion in three cases. We found no significant differences in treatment results as per the treatment method and fracture type. Conclusion Patellar fracture after TKA with retained patella is infrequent, with relatively improved clinicoradiological results over those of patellar fracture after TKA with resurfaced patella reported in the literature. The improved results did not differ as per the treatment method and fracture type.

Background: Analyzing the current trends in meniscal allograft transplant (MAT) is important. However, no recent descriptive epidemiological study based on a national registry database has been reported. Purpose: To assess serial trends in the incidence of MAT in the Republic of Korea between 2010 and 2018, stratified by age and sex. Study Design: Descriptive epidemiology study. Methods: The number of MAT procedures between 2010 and 2018 was assessed using the Korean National Health Insurance claims database. We used code N0825 for isolated MAT and code N0820 for MAT combined with other procedures, such as ligament reconstruction, realignment surgery, and cartilage procedures. The incidence of MAT was calculated using the general population data of the Republic of Korea, and Poisson log-linear regression analysis was used to assess statistical serial trends. Results: A total of 369 patients underwent MAT in 2010 and 774 in 2018, with an increase of 47.6%. The incidence of MAT per 100,000 person-years in the Republic of Korea increased significantly during the period studied, from 0.75 in 2010 to 1.50 in 2018 (annual relative risk = 1.09; 95% CI, 1.08-1.10; P < .001), whereas the rate of MAT combined with other procedures increased from 5.1% in 2014 to 16.0% in 2018. MAT was mostly performed in men in their early 20s. Most MAT procedures were performed in the summer and winter, with distinct seasonal variances. Conclusion: In the Republic of Korea, the incidence of MAT in 2018 was 1.50 per 100,000 person-years, with an average annual increase of 10% since 2010. MAT was mostly performed in men in their early 20s, and the rate of MAT combined with other procedures has increased since 2014.

Background: Adverse effects of graft extrusion after meniscal allograft transplantation (MAT) are difficult to assess and can be determined only in the long term using a simple radiograph. Recently, subchondral bone marrow lesions (BMLs) detected on magnetic resonance imaging (MRI) scans have been used to evaluate the outcomes or prognoses of various knee surgeries. However, whether subchondral BMLs on MRI scans reflect the effects of allograft extrusion remains unclear. Hypothesis: Subchondral BML in the lateral compartment of the knee joint on postoperative MRI scans would be associated with graft extrusion after lateral MAT. Study Design: Case-control study; Level of evidence, 3. Methods: Overall, 170 patients with lateral MAT between 2008 and 2013 were classified into extrusion (≥3 mm) and nonextrusion (Results: Of the 170 patients, 20 (11.8%) had subchondral BML on the latest MRI scans at a mean 53.6 ± 31.2 months postoperatively, with 14 and 6 patients in the extrusion and nonextrusion groups, respectively. Chi-square analysis showed a significant association between allograft extrusion and subchondral BMLs ( P = .025). Logistic regression analysis showed that extrusion and age were significant factors associated with subchondral BML ( P = .011 and .004, respectively). However, no differences were observed in the Lysholm scores in accordance with the subchondral BML ( P = .248). Conclusion: Subchondral BMLs on postoperative MRI scans were associated with graft extrusion after lateral MAT. However, there was no difference in clinical outcomes according to subchondral BML.

Purpose To evaluate the true effects of chronologic age on the clinical and radiologic outcomes of open wedge high tibial osteotomy (OWHTO) in a sample of patients who had been matched according to cartilage status in the medial and lateral compartments. Methods The records of 107 OWHTO cases were reviewed. To evaluate potential differences in the outcomes according to age, the subjects were divided into 2 groups by the median age: older group and younger group. The Hospital for Special Surgery scores and Knee Society objective and functional scores before surgery and at the latest follow-up were compared between the groups. Then, the subjects in each group were matched 1:1 according to cartilage status in the medial and lateral compartments, which had been evaluated during arthroscopy prior to the osteotomy. The clinical scores were compared between the matched groups. The change in the medial joint space width (ΔJSW) from 6 to 12 months postoperatively to the latest follow-up was also compared before and after matching. Results With a median age of 55 years, 44 and 63 cases were allocated into the older and younger groups, respectively. Prior to cartilage status matching, the latest Hospital for Special Surgery and Knee Society functional scores were significantly higher in the older group (P = .042 and P = .025, respectively). After matching, each group included 41 cases, and the differences in these clinical scores were no longer significant (P = .164 and P = .165, respectively). No difference in ΔJSW was observed between the groups, regardless of matching status (P = .901 before matching, P = .979 after matching). Conclusions The clinical outcomes of OWHTO were affected by cartilage status, rather than by the chronologic age itself. No difference was observed in the radiologic outcome (ΔJSW) with respect to age. OWHTO should not be waived in treating elderly patients without highly advanced cartilage degeneration simply because of their chronologic ages. Level of Evidence Level III, retrospective cohort study.

Radial tears of the lateral meniscus are often located in the junction of the middle and posterior third or posterior tibial attachment. However, we observed that a few cases of radial tears occurred in the anterior third of the lateral meniscus, and in many cases, they were accompanied by horizontal tears.Radial tears are more frequently accompanied by horizontal tears in the anterior third of the lateral meniscus than in other regions.From July 2006 to May 2019, patients who underwent arthroscopic surgery for radial tears of the lateral meniscus were included. Patients with radial tears in the anterior third of the lateral meniscus were classified into the anterior group and those with radial tears in the middle and posterior third were classified into the comparison group. Magnetic resonance imaging and arthroscopic findings were reviewed to evaluate whether radial tears were accompanied by other types of tears, especially horizontal tears. The incidence of complex tears between the two groups was compared.Eighty knees in 79 patients were included. The mean age at the time of surgery was 44.1±16.9 years. The anterior group included 30 knees, and 19 (63.3%) of those also had horizontal tears. In the anterior group, all complex tears were accompanied by horizontal tears, and no other types of accompanying tears were observed. The comparison group included 50 knees, and 16 (32%) of those also had other types of tears. Of the 16 complex tears, 14 had horizontal tears and 2 had longitudinal tears. The incidence of complex tear was significantly higher in the anterior group than in the comparison group (p.001).Radial tears occurring at the anterior third of the lateral meniscus are frequently accompanied by a horizontal tear. It is important to be aware and predict the occurrence of such characteristic tears and to do proper surgical procedures.IV; Cross-sectional study.

Background: The aging process is accompanied by several conditions that could affect the outcome of meniscal allograft transplantation (MAT). These conditions have made it difficult for clinicians to determine the effect of chronologic age on survivorship after MAT. Hypothesis: Advanced age does not have an adverse effect on survivorship of MAT when controlling for age-related factors, such as cartilage status and time from previous meniscectomy. Study Design: Cohort study; Level of evidence, 3. Methods: The records of 264 consecutive patients who underwent primary medial or lateral MAT were reviewed. To check whether there was a difference in MAT survivorship according to age, a cutoff value was calculated from a time-dependent receiver operating characteristic curve. Survival rates, as well as clinical improvement as determined using the Lysholm score, were compared between groups divided by the cutoff value. Patients were matched for cartilage status and elapsed time from previous meniscectomy. Differences in survivorship and clinical outcomes were assessed between the matched groups. Results: A time-dependent receiver operating characteristic curve showed that the difference in MAT survivorship was maximized with a cutoff age of 43 years. Kaplan-Meier analysis showed a significant difference in MAT survivorship between the older and younger groups (log-rank test, P = .01). However, after matching for cartilage status and time from previous meniscectomy, which left 56 patients per group, there was no significant difference in MAT survivorship (log-rank test, P = .10) between the groups. Regarding clinical outcomes, the mean Lysholm scores were not significantly different between the older and younger groups ( P = .19, before matching; P = .39, after matching). Conclusion: MAT survivorship was more affected by age-related prognostic factors, such as cartilage status and time from previous meniscectomy, than age itself. Clinical outcomes did not show differences according to age, either.

Background Patients with severe preoperative varus deformity have been reported to have high rates of loosening after total knee arthroplasty (TKA), primarily on the tibial side. This study investigated whether a short extension stem for the tibial component in severely varus knees would reduce the failure rate due to loosening on the tibial side. Methods Patients who underwent TKA, performed by a single surgeon using a single implant between November 1998 and January 2009, were retrospectively evaluated. Patients diagnosed with primary osteoarthritis, having a hip-knee-ankle axis greater than varus 8° on preoperative long-film radiographs, and postoperatively followed up for more than 2 years were included. Patients were divided into “stem” and “nonstem” groups, followed by 1:1 propensity score matching according to age, gender, body mass index, preoperative mechanical axis, and postoperative alignment. Tibial loosening rates in the 2 groups were compared. Results The study cohort included 602 patients, divided into “stem” and “nonstem” groups. Propensity score matching yielded 88 pairs of patients. Mean follow-up duration was similar in the stem and nonstem groups (109.22 vs 103.81 months, P = .451). None of the patients in the stem group, compared with 5 in the nonstem group, experienced aseptic loosening. The overall implant survival rate was significantly higher in the stem group than in the nonstem group (P = .0201). Conclusion Using a short extension stem for the tibial component in primary TKA in patients with severe varus deformity greater than 8° may reduce the rate of loosening of the tibial side and increase the longevity of the implant. Level of evidence Level III.

OBJECTIVES We aimed to identify the optimal lower limb position for an ultrasound (US)-guided anterior approach to a sciatic nerve block. METHODS We included 45 patients who met the following criteria: American Society of Anesthesiologists physical status of 1 to 3, age between 18 and 80 years, and scheduled to undergo knee surgery that required a sciatic nerve block. The lower limbs of each patient were placed in the following 4 positions: N, neutral; ER, external rotation of the hip (angle, 45°); ER/F15, ER (angle, 45°) and flexion (angle, 15°) of the hip; and ER/F45, ER (angle, 45°) and F (angle, 45°) of the hip. An investigator acquired US scans of the sciatic nerve in each position, and the visibility score and depth of the sciatic nerve from the skin were analyzed. RESULTS The visibility scores were significantly higher in positions ER/F15 and ER/F45 than in positions ER and N (P

Background The purpose of this study is to compare the clinical and radiographic outcomes of total knee arthroplasty (TKA) with patellar retention in accordance with the severity of patellofemoral arthritis. Methods We retrospectively reviewed patients who underwent TKA with patellar retention using the NexGen LPS or LPS-flex system between September 2010 and May 2015. The radiographic severity of patellofemoral arthritis was categorized according to the Iwano classification system, and subjects were divided into mild (stage 0-I) and moderate to severe (stage II-IV) groups. Clinical outcomes were evaluated using the Hospital for Special Surgery score, Knee Society Score, function score, Western Ontario and McMaster Universities Osteoarthritis Index, and Feller score. Radiographic outcomes were assessed using the congruence angle, patellar tilt angle, and lateral patellar displacement. The minimum follow-up for clinical and radiographic evaluation was 2 years. Clinical and radiographic outcomes were compared between the 2 groups preoperatively and at the time of the last follow-up. Results Four hundred seventy-four knees were enrolled and assigned to mild (n = 208) or moderate to severe (n = 266) groups. The preoperative Feller score was significantly lower in the moderate to severe group (P = .030), whereas the postoperative clinical and radiographic results did not differ significantly between the 2 groups. Conclusion Clinical and radiographic outcomes did not differ in accordance with the severity of patellofemoral arthritis after a minimum 2 years of follow-up of patients treated with TKA with patellar retention. Good outcomes were obtained with patellar retention in TKA, even in patients with advanced patellofemoral osteoarthritis.