Mesenchymal Stem Cells for Enhanced Healing of the Medial Collateral Ligament of the Knee Joint.

Background and Objectives: The medial collateral ligament (MCL) is one of the major supporting ligaments of the knee joint, and MCL injuries are common where excessive valgus loading is applied to the knee joint. Although most MCL injuries can be treated conservatively, healing of the MCL can take several weeks to months. Furthermore, once injured, the biomechanical properties of the healed MCL differ from those of the native MCL, resulting in an increased risk of re-injury and chronic remnant symptoms. Mesenchymal stem cells (MSCs), owing to their therapeutic potential, have been investigated in various musculoskeletal injuries, and some preclinical studies regarding MSC-based approaches in MCL injuries have shown promising results. Despite satisfactory results in preclinical studies, there is still a lack of clinical studies in the orthopedic literature. This article describes the basic knowledge of the MCL, standard treatments for MCL injuries, and recent studies regarding the application of MSCs for enhanced healing of the MCL. MSC-based approaches are expected to be a potential therapeutic option for enhanced healing of the MCL in the future.

Arthroscopic cystectomy for Baker's cysts with and without one-way valve lesions: incidence of one-way valve lesion, associated pathologies, and clinical outcomes.

INTRODUCTION: A one-way valve lesion plays an important role in the formation of Baker's cysts and serves as an important landmark for accessing these cysts during arthroscopic surgery. This study aimed to investigate the incidence of one-way valve lesions and their effect on clinical outcomes in patients who underwent arthroscopic cystectomy for Baker's cysts. MATERIALS AND METHODS: Patients who underwent arthroscopic cystectomy for Baker's cysts between June 2005 and November 2017 were retrospectively reviewed. Patient demographic characteristics, radiologic/arthroscopic findings (presence of one-way valve lesions, concurrent chondral and meniscal lesions, and cyst wall thickness), and clinical outcomes (clinical recurrence rate, Lysholm score, and complications) at the 2-year follow-up were evaluated. Subgroup analysis was performed to compare clinical outcomes between patients with and without one-way valve lesions. RESULTS: Thirty patients (mean age, 57.4 ± 9.4 years) were included in this study. One-way valve lesions were surgically documented in 11 patients (36.7%). Ten patients (33.3%) had chondral lesions with an International Cartilage Repair Society grade ≥ 3, and 23 patients (76.7%) had concurrent chondral and meniscal lesions. At the 2-year follow-up, none of the patients had experienced clinical recurrence; the mean Lysholm score was 76.3 ± 17.5 (48-100). Three patients reported persistent pain, while two reported numbness or paresthesia. Subgroup analysis showed no significant differences in clinical recurrence rates, Lysholm scores, and complication rates between the groups. CONCLUSIONS: The incidence of one-way valve lesions during arthroscopic cystectomy for Baker's cysts was lower than that previously reported. Arthroscopic cystectomy showed good clinical results in patients with and without these lesions.

Senolytic drugs relieve pain by reducing peripheral nociceptive signaling without modifying joint tissue damage in spontaneous osteoarthritis.

Aging is a risk factor for the development of osteoarthritis (OA), a progressive joint disease leading to cartilage damage, pain, and loss of function. In a mouse model of OA, senolytic drugs to selectively clear senescent cells (SnCs) that accumulate with injury or aging yielded a chondroprotective effect; however, this therapeutic benefit was limited in aged mice. Due to inconsistency between cartilage destruction and pain-associated symptoms, we studied the therapeutic effect of senolytics on joint pain in spontaneous OA. We orally treated 21- and 22-month old mice with an ABT263 and Dasatinib and Quercetin (D+Q) drug combination. Selective elimination of the SnCs that accumulated in the articular cartilage and synovium by these two drugs did not alter cartilage degeneration and abnormal bone changes during spontaneous OA progression. Treatment reduced thermal and mechanical hyperalgesia associated with OA and peripheral sensitization through decreased expression of axon guidance proteins (nerve growth factor NGF/TrkA) and nociceptive neuron (calcitonin gene-related peptide, CGRP) projection to the synovium, subchondral bone marrow, and dorsal root ganglion, and knee joint angiogenesis. Selective removal of the SnCs from in vitro cultures of synovial cells from human OA patients also decreased expression of senescent markers, axonal growth-promoting factors, such as NGF, and angiogenesis markers. We suggest that systemic administration of ABT263 and D+Q is an exciting therapeutic approach to age-related OA pain.

Functional outcomes of residual varus alignment versus mechanical alignment in total knee arthroplasty for varus osteoarthritis: A preferred reporting items for systematic reviews and meta-analyses-compliant meta-analysis.

BACKGROUND: One in five patients with mechanical alignment (MA) after total knee arthroplasty (TKA) was reportedly dissatisfied. As constitutional varus knees are common, restoring the patients' natural residual varus (RV) alignment is as an appealing alternative to neutral MA. This meta-analysis aimed to evaluate the effects of RV alignment on the functional outcomes compared with those of MA in TKA for the knees with varus osteoarthritis. METHODS: The MEDLINE/PubMed, Cochrane Library, and EMBASE databases were comprehensively searched for papers comparing the effects of RV alignment and MA on the functional outcomes from the time of inception of the databases to July 2020. Studies comparing the functional outcomes in the knees subjected to TKA with RV alignment (case group) and MA (control group) were included. The Knee Society knee and functional scores (KSKS and KSFS, respectively), Western Ontario and McMaster University Osteoarthritis Index (WOMAC), Oxford knee score (OKS), and forgotten joint score (FJS) were compared. RESULTS: Seven studies were finally included; all studies showed a low risk of selection bias and provided detailed demographic data. The pooled mean difference in the KSKS (0.06, 95% confidence interval [CI]: -0.14 to 0.27; p = 0.55) and KSFS (0.08, 95% CI: -0.08 to 0.35; p = 0.56) between RV alignment and MA did not significantly differ. The pooled mean differences in the WOMAC (-0.25, 95% CI: -0.57 to 0.07; p = 0.12), OKS (0.06, 95% CI: -0.15 to 0.27; p = 0.56), and FJS (0.41, 95% CI: -0.18 to 1.00; p = 0.18) between the groups were not significant. CONCLUSION: The beneficial effects of RV alignment on the functional outcomes are limited compared to those of MA in TKA for varus osteoarthritis to date. Currently, TKA with neutral MA should be considered as the gold standard.

Component gap measurement reflects the planned gap balance during total knee arthroplasty more accurately and reliably than bone surface gap measurement.

PURPOSE: This study aimed to compare the reliability of two gap assessment methods (component and bone surface gap measurement vs. planned gap balance) and identify the contributors to component gaps other than planned gaps. METHODS: The prospectively collected data for 122 consecutive primary total knee arthroplasties (TKAs; 114 patients). After femoral planning for gap balancing, the medial and lateral planned gaps were calculated (planned gap). The established medial extension and flexion gaps (MEG and MFG, respectively) and lateral extension and flexion gaps (LEG and LFG, respectively) were measured with and without the TKA components (bone surface and component gaps) at 0° and 90° flexion. The intraclass and Pearson correlation coefficients for each gap measurement method were assessed using planned gap values, and multiple linear regression analyses were performed to identify the contributors to component gaps. RESULTS: Compared with the bone surface gap measurement, the component gap measurement showed higher reliability and stronger correlation with the planned gap balance for each gap. The changes in the medial posterior femoral offset contributed to the MEG and LEG, whereas those in the joint line height contributed to the LEG. The changes in the hip-knee-ankle angle and lateral posterior femoral offset contributed to the LFG. CONCLUSION: Component gap measurements of the established gap more accurately and reliably reflect the planned gap balance than do bone surface gap measurements. The established gaps are affected by several factors other than femoral planning.

Residual varus alignment can reduce joint awareness, restore joint parallelism, and preserve the soft tissue envelope during total knee arthroplasty for varus osteoarthritis.

PURPOSE: The objectives were to compare the coronal joint configuration of the knee joints, coronal gap imbalances requiring substantial medial release, and patient-reported outcomes, including the forgotten joint score, between knees in which residual varus alignment was intentionally allowed according to an individualised lower limb analysis and those with mechanical alignment in total knee arthroplasty for varus osteoarthritis. METHODS: Consecutive primary navigated total knee arthroplasty procedures for varus osteoarthritis were retrospectively reviewed. The study cohort was stratified based on whether residual varus alignment was intentionally allowed. Propensity-score matching was performed based on the baseline characteristics, including demographic characteristics, preoperative radiological measurements, and the Western Ontario and McMaster University Osteoarthritis Index (mechanical alignment group vs residual varus group). The patient-reported outcomes and coronal joint line orientation of the knee (relative to the ground) and ankle were evaluated. Coronal gap differences and coronal gap imbalances were analysed using intraoperative gap measurements. RESULTS: Relative to the ground and ankle, the postoperative knee joint line orientation slanted down laterally in the mechanical alignment group (- 3.05˚ ± 1.62, relative to the ground; - 2.65˚ ± 1.56, relative to the ankle joint), but was parallel in the residual varus group (- 0.75˚ ± 1.59, relative to the ground; - 0.95˚ ± 1.71, relative to the ankle joint). Coronal gap differences at extension and the proportion of coronal gap imbalances requiring substantial medial release were 1.27 ± 1.53 and 6% in the residual varus group and 2.32 ± 1.24 and 15% in the mechanical alignment group. Postoperatively, the residual varus group showed higher Western Ontario and McMaster University Osteoarthritis Index scores and total forgotten joint scores than the mechanical alignment group (6.97 ± 4.75 vs. 10.31 ± 5.74 and 56.42 ± 12.85 vs. 45.69 ± 14.49, respectively). CONCLUSION: Intentionally allowed residual varus alignment with individualised analysis of lower limb alignment restored the parallel joint line of the knees, preserved the soft tissue envelope, and reduced joint awareness after total knee arthroplasty for varus osteoarthritis. LEVEL OF EVIDENCE: Therapeutic, Level III retrospective case-control study.

Association of Preoperative Tibial Varus Deformity With Joint Line Orientation and Clinical Outcome After Open-Wedge High Tibial Osteotomy for Medial Compartment Osteoarthritis: A Propensity Score-Matched Analysis.

BACKGROUND: The correction of lower limb deformity should be performed at the site of deformity to maintain knee joint orientation. However, the effectiveness of open-wedge high tibial osteotomy (OWHTO) for treatment of medial osteoarthritis in varus malalignment without definite tibial varus deformity has not been confirmed. PURPOSE/HYPOTHESIS: This study aimed to compare the clinical and radiologic outcomes after OWHTO in patients without tibial varus deformity versus patients with tibial varus deformity after matching for confounding factors. We hypothesized that these outcomes would be inferior in patients without tibial varus deformity. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: The outcomes of 133 OWHTO operations for medial osteoarthritis in 107 patients were retrospectively reviewed after follow-up for >2 years. The patients were divided into group 1 (tibia with varus deformity, preoperative medial proximal tibial angle [MPTA] <85°) and group 2 (tibia without varus deformity, preoperative MPTA ≥85°). The confounding factors, including patient characteristics, preoperative limb alignment, degree of osteoarthritis, and correction angle, were matched using propensity score matching. The radiologic parameters, including MPTA and joint line obliquity, were evaluated preoperatively, between 6 and 12 months postoperatively, and at the last follow-up. The radiologic outcomes were assessed using the medial joint space width and mechanical hip-knee-ankle angle. The clinical outcomes were evaluated by the Hospital for Special Surgery knee score, Knee Society Score (KSS), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score. The clinical and radiologic outcomes were compared between the groups. The proportions of patients achieving improvement in the clinical outcome beyond the minimal clinically important difference (MCID) or minimally important change were compared between the groups. RESULTS: After propensity score matching, 32 patients were selected for each group. The mechanical hip-knee-ankle angle was corrected without significant difference from a mean ± SD varus angle of 8.0°± 3.3° to valgus angle of -3.2°± 2.5° in group 1 and from varus 8.0°± 3.6° to valgus -3.9°± 1.7° in group 2. The preoperative joint line obliquity was greater in group 2 as compared with group 1 (2.2°± 2.2° vs -0.4°± 1.8°, P < .001). With a similar 10° correction angle, the postoperative MPTA and joint line obliquity were 96.6°± 2.5° and 5.3°± 2.3°, respectively, in group 2, which were greater than 94.0°± 2.6° and 3.5°± 1.8°, respectively, in group 1 (both P < .001). The changes in joint space width and mechanical hip-knee-ankle angle were not significantly different between the groups over the follow-up period. At the last follow-up, the postoperative KSS objective score and WOMAC pain score in terms of symptom improvement were not significantly different between groups (P = .092 and .068). However, the postoperative KSS and WOMAC functional scores were significantly worse in group 2 than in group 1 (77.3 ± 14.1 vs 84.4 ± 11.6, P = .044; 10.3 ± 9.2 vs 5.6 ± 7.2, P = .001). In group 1, 96.9% and 100% of patients showed improvements of >10 points in the KSS functional score and 15 points in the WOMAC functional score based on MCID or minimally important change. Meanwhile, 65.6% and 81.3% of patients in group 2, which were significantly lower than those of group 1, were improved beyond the MCID or minimally important change (P = .001 and .024, respectively). CONCLUSION: In varus malalignment, the knee joint line was more oblique in patients without tibial varus deformity after OWHTO pre- and postoperatively. The clinical outcomes in terms of functional scores were inferior in patients without tibial varus deformity. However, the radiologic outcomes and symptomatic improvement after OWHTO were comparable regardless of the preoperative tibial varus deformity on midterm follow-up.

Arthroscopy-controlled medial reefing and lateral release for recurrent patellar dislocation: clinical, radiologic outcomes and complications.

BACKGROUND: Few studies have reported the clinical outcomes of the medial reefing procedure and lateral release with arthroscopic control of medial retinacular tension in patients with recurrent patellar dislocation. The purpose of this study was to investigate the clinical, radiologic outcomes and complications of arthroscopy-controlled medial reefing and lateral release. METHODS: Patients who underwent arthroscopy-controlled medial reefing and lateral release for recurrent patellar dislocation between November 2007 and June 2017 were retrospectively evaluated. The clinical outcome (Kujala score), radiologic outcome (congruence and patellar tilt angles), and complications were evaluated at final follow-up. The results were also compared with literature-reported outcomes of other surgical procedures for patellar dislocation. RESULTS: Twenty-five patients (mean age, 18.3 ± 4.8 years) were included in the study. The mean clinical follow-up period was 7.0 ± 2.5 (range, 3.8-12.2) years. The mean Kujala score was significantly improved from 54.7 ± 14.0 (range, 37-86) preoperatively to 91.0 ± 7.6 (range, 63-99) at a mean follow-up period of 7 years (P < 0.001). The radiologic results also significantly improved from 17.8° ± 5.9° to 6.8° ± 2.4° (P < 0.001) in the congruence angle and from 17.5° ± 8.2° to 5.6° ± 3.1° (P < 0.001) in the patella tilt angle at a mean follow-up period of 3.6 years. One patient developed a redislocation after a traumatic event, and two patients showed patellofemoral osteoarthritis progression. CONCLUSIONS: Arthroscopy-controlled medial reefing and lateral release significantly improved the clinical and radiologic outcomes of the patients with recurrent patellar dislocation at a mean follow-up period of 7 years. The results of this study are comparable with the literature-reported outcomes of other surgical procedures for patellar dislocation. LEVEL OF EVIDENCE: Level IV, retrospective therapeutic case series.

Posterior tibial slope is a modifiable predictor of relatively large extension gaps in total knee arthroplasty for degenerative osteoarthritis.

BACKGROUND: During total knee arthroplasty (TKA) for osteoarthritis, the sagittal gap imbalance (SGI) with a relatively large extension gap is an important surgical challenge. We determined the predictors of SGI with a relatively large extension gap and evaluated the surgical outcomes of knees with SGI. METHODS: 551 consecutive cases of primary TKA for osteoarthritis were retrospectively reviewed. The cohort was divided into two groups according to the SGI and statistically matched according to baseline characteristics via the inverse probability of treatment weighting method. Multiple linear and logistic regression analyses were performed to determine the predictors of sagittal gap difference (SGD) and SGI. Intergroup differences in clinical and radiological outcomes were analyzed. RESULTS: Of all the knees included, 8.5% (n = 45) presented with SGI with a relatively large extension gap and required femoral sagittal balancing to manage SGI. The hyperextension angle (HA), preoperative joint line convergence angle (JLCA), and the change in posterior tibial slope (PTS) significantly correlated to SGD and predicted SGI with a relatively large extension gap. SGI group showed significant changes in femoral posterior condylar offset and joint line height compared to those without SGI (1.48 vs -0.45, 1.37 vs -0.51, respectively). Postoperative ROM and knee society knee scores were lower in SGI group. CONCLUSION: Knees requiring sagittal balancing to manage SGI with a relatively large extension gap is not uncommon in TKA for osteoarthritic knees. The change in PTS is an independent and modifiable predictor of SGI.

Supervised Rehabilitation May Lead to Better Outcome than Home-Based Rehabilitation Up to 1 Year after Anterior Cruciate Ligament Reconstruction.

Background and objectives: Previous studies consistently found no significant difference between supervised and home-based rehabilitation after anterior cruciate ligament reconstruction (ACLR). However, the function of the nonoperative knee, hamstring strength at deep flexion, and neuromuscular control have been overlooked. This prospective observational study was performed to investigate the outcomes after ACLR in operative and nonoperative knees between supervised and home-based rehabilitations. Materials and Methods: After surgery, instructional videos demonstrating the rehabilitation process and exercises were provided for the home-based rehabilitation group. The supervised rehabilitation group visited our sports medicine center and physical therapists followed up all patients during the entire duration of the study. Isokinetic muscle strength and neuromuscular control (acceleration time (AT) and overall stability index (OSI)) of both operative and nonoperative knees, as well as patient-reported knee function (Lysholm score), were measured and compared between the two groups 6 months and 1 year postoperatively. Results: The supervised rehabilitation group showed higher muscle strength of hamstring and quadriceps in nonoperative knees at 6 months (hamstring, p = 0.033; quadriceps, p = 0.045) and higher hamstring strength in operative and nonoperative knees at 1 year (operative knees, p = 0.035; nonoperative knees, p = 0.010) than the home-based rehabilitation group. At 6 months and 1 year, OSIs in operative and nonoperative knees were significantly better in the supervised rehabilitation group than in the home-based rehabilitation group (operative knees, p < 0.001, p < 0.001; nonoperative knees, p < 0.001, p < 0.001, at 6 months and 1 year, respectively). At 1 year, the supervised rehabilitation group also demonstrated faster AT of the hamstrings (operative knees, p = 0.016; nonoperative knees, p = 0.036). Lysholm scores gradually improved in both groups over 1 year; however, the supervised rehabilitation group showed higher scores at 1 year (87.3 ± 5.8 vs. 75.6 ± 15.1, p = 0.016). Conclusions: This study demonstrated that supervised rehabilitation may offer additional benefits in improving muscle strength, neuromuscular control, and patient-reported knee function compared with home-based rehabilitation up to 1 year after ACLR.

Effectiveness of modeling videos on psychological responses of patients following anterior cruciate ligament reconstruction: A pilot randomized trial.

BACKGROUND: To date, much of the rehabilitation following anterior cruciate ligament reconstruction (ACLR) has centered on physical components. However, clinical outcomes including return to sport after ACLR depends on not only physical recovery but also psychological components. This study was performed to assess the feasibility of 6-month modeling video intervention on psychological responses following ACLR. METHODS: Following the baseline assessment of psychological measures through Knee Self Efficacy Scale (K-SES), ACL-Return to Sport after Injury (ACL-RSI), and Tampa Scale of Kinesiophobia-11 (TSK-11), 32 patients scheduled for ACLR were randomly assigned to intervention (n = 10), placebo (n = 11), or control (n = 11) group. Six modeling videos and placebo videos were developed by the investigators. Intervention and placebo groups watched their respective videos during their follow-up visits while control group did not. All groups completed psychological assessments during hospitalization, at 2 weeks, at 6 weeks, at 3 months, and at 6 months following ACLR. Also, Knee Injury and Osteoarthritis Outcome Score (KOOS) was used to evaluate symptoms and function of the knee at 3 and 6 months after surgery. RESULTS: No significant changes in K-SES, ACL-RSI, and TSK-11 scores over 6-month period were observed among groups (P = .808, P = .574, P = .888, respectively). Compared with baseline, only the scores of K-SES improved with statistical significance in the intervention, placebo, and control groups (P = .05, .01, .00) at 6 months after ACLR. The KOOS subscale scores were not significantly different among the intervention, placebo, and control groups at 3 and 6 months. CONCLUSION: A modeling video intervention, although feasible, was not effective in addressing the psychological risk factors in patients undergoing ACLR.

Use of bone wax reduces blood loss and transfusion rates after total knee arthroplasty.

BACKGROUND: Unnecessary costs and complications can be reduced by minimizing blood loss and allogeneic blood transfusion in cases of total knee arthroplasty (TKA). This study evaluated the effectiveness of bone wax in reducing blood loss and transfusion rates after TKA. METHODS: A total of 674 consecutive TKAs performed for degenerative osteoarthritis were retrospectively reviewed. Propensity score-matching and inverse probability of treatment weighting analyses were performed for demographics, comorbidities, use of medications, preoperative laboratory findings and radiologic prosthetic coverage of osteotomy surface. In the bone wax group, bone wax (2.5 g) was applied to the uncovered bone section around the prostheses along with the topical administration of tranexamic acid, whereas hemostasis was achieved in the control group with the topical administration of tranexamic acid. Intergroup comparisons of estimated blood loss, decreases in hemoglobin (Hb) levels, and transfusion rates were performed. RESULTS: The mean estimated blood loss and volume of postoperative drainage were reduced in the bone wax group. The maximum decreases in Hb levels on postoperative days 1, 3, 5, and 7 were 1.8 ± 0.7 ml, 2.5 ± 0.8 ml, 2.7 ± 0.8 ml, and 2.8 ± 0.8 ml in the bone wax group and 2.1 ± 1.0 ml, 3.0 ± 1.2 ml, 3.1 ± 1.1 ml, and 3.2 ± 1.1 ml in the control group, respectively. The postoperative transfusion rates decreased markedly from 8.8% to 2.0% when bone wax was used. CONCLUSIONS: The use of bone wax significantly reduced blood loss, decreased Hb levels, and the risk of transfusion. LEVEL OF EVIDENCE: Level III, Therapeutic studies.

Poorer dynamic postural stability in patients with anterior cruciate ligament rupture combined with lateral meniscus tear than in those with medial meniscus tear.

BACKGROUND: Only limited data are available regarding postural stability between anterior cruciate ligament (ACL)-injured patients with medial meniscus (MM) tear and those with lateral meniscus (LM) tear. The purpose of this study was to compare preoperative postural stability for both involved and uninvolved knees in ACL rupture combined with MM and LM tears. It was hypothesized that there would be a significant difference in postural stability between these two groups. METHODS: Ninety-three ACL-injured patients (53 combined with MM tears vs. 40 combined with LM tears) were included. Static and dynamic postural stability were evaluated with the overall stability index (OSI), anterior-posterior stability index (APSI), and medial-lateral stability index (MLSI) using stabilometry. Knee muscle strength was evaluated using an isokinetic testing device. RESULTS: In the static postural stability test, none of the stability indices showed significant differences between the two groups for both knees (p > 0.05). In the dynamic postural stability test for involved side knees, the OSI and APSI were significantly higher in the LM tear group compared to the MM tear group (OSI: 2.0 ± 0.8 vs. 1.6 ± 0.5, p = 0.001; APSI: 1.5 ± 0.6 vs. 1.3 ± 0.5, p = 0.023), but not the MLSI (p > 0.05). In the static and dynamic postural stability tests in each group, there were no significant differences between the involved and uninvolved side knees (p > 0.05). There was no significant difference in the knee muscle strength between the two groups (p > 0.05). All postural stability showed no significant correlation with knee muscle strength (p > 0.05). CONCLUSION: Dynamic postural stability was poorer in patients with ACL rupture combined with LM tear than in those with MM tear. Therefore, close monitoring for postural stability would be necessary during preoperative and postoperative rehabilitation, especially for patients with ACL rupture combined with LM tear. LEVEL OF EVIDENCE: LEVEL III.

Preoperative Supine Radiographs Are More Accurate Than Standing Radiographs for Preoperative Planning in Medial Open-Wedge High Tibial Osteotomy.

PURPOSE: To verify the accuracy of supine nonweight-bearing radiography versus standing radiography in preoperative planning and to determine the predictors of unintended limb alignment correction in medial open-wedge high tibial osteotomy (OWHTO). METHODS: Consecutive patients who underwent medial OWHTO for medial osteoarthritis of the knee with varus alignment were retrospectively reviewed. The analyzed pre- and postoperative radiologic measurements included postoperative mechanical axis deviation (MAD) on standing whole-leg radiographs (WLRs), the predicted value of the postoperative MAD on the preoperative supine (predicted MADsupine) radiograph, and standing WLRs (predicted MADstand). Multiple linear regression analysis was used to identify variables predicting the postoperative MAD and unintended MADstand correction, defined as the difference between predicted MADstand and postoperative MAD. RESULTS: Predicted MADsupine showed statistically greater reliability in predicting postoperative MAD than predicted MADstand (intraclass correlation coefficient, 0.82 vs 0.45). Postoperative MAD was correlated with the predicted MADsupine and the difference in hip-knee-ankle angle between preoperative standing and supine WLRs (ΔHKA anglestand-supine) (R =763, R2 = 0.582, adjusted R2 = 0.569, P < .001) and did not differ significantly from the predicted MADsupine, with a mean difference of 0.28% ± 5.11% (P = .656). The mean unintended MADstand correction was 6.52% ± 8.66%. The difference in preoperative MAD between standing and supine WLRs was a significant predictor for unintended MADstand correction (ß = -0.350, P = .004). CONCLUSIONS: Preoperative planning with supine WLRs can predict postoperative limb alignment in medial OWHTO more accurately than standing radiographs. The clinical significance of the ΔHKA anglestand-supine for the risk of overestimation of postoperative limb alignment might be low because of the low power in the prediction model and small value of the ΔHKA anglestand-supine. Preoperative soft-tissue laxity was significantly correlated with unintended correction of postoperative limb alignment resulting from preoperative planning with standing radiographs. LEVEL OF EVIDENCE: Level IV, retrospective comparative study.

Effects of intravenous iron monotherapy for patients with iron deficient anemia undergoing total knee arthroplasty.

BACKGROUND: Unnecessary costs and complications can be reduced by increasing hemoglobin (Hb) levels and minimizing blood transfusions in patients who underwent total knee arthroplasty (TKA). This study aimed to determine the effects of intravenous iron monotherapy before TKA on preoperative iron deficient anemia and postoperative transfusion rates. METHODS: This prospective cohort study included 45 patients scheduled for TKA in the experimental group (Group I) and 221 patients who underwent TKA in 2015 and 2018 in the control group (Group C). One thousand milligrams of ferric carboxymaltose was administrated 1 month before TKA in group I. Intergroup comparison of the rate and total volume of transfusion, perioperative changes in Hb and analysis of iron metabolism variables in group I were performed. Subgroup analysis of Group I was conducted according to the response to iron monotherapy. RESULTS: Although Hb levels increased after intravenous iron monotherapy in Group I, postoperative transfusion rates in Groups I and C were 17.8% and 18.6%, respectively, without significant intergroup differences in the rate and total units of transfusion. Ferritin level and transferrin saturation were corrected in both subgroups of Group I. Only 17 patients (37.78%) showed response to iron monotherapy, with an Hb increase of 1.0 g/dL or more. Subgroup analysis showed lower proportions of coexisting chronic diseases, including chronic kidney disease in responders. CONCLUSION: IV iron monotherapy was shown to be insufficient in successfully treating preoperative iron-deficient anemia to reduce postoperative allogenic blood transfusion in patients who underwent TKA. As preoperative anemia should be managed due to the high rates of postoperative transfusion for this surgery, clinicians should consider the complex interplay among the causal factors of anemia, apart from ID, in patients with preoperative anemia who are scheduled for TKA.

Arthroscopic-assisted anatomical reconstruction of the posterolateral corner of the knee joint.

Several surgical techniques have been suggested to anatomically reconstruct the posterolateral corner of the knee joint. However, most of them are open techniques that require dissection of the skin and soft tissues without utilizing the advantages of arthroscopic-assisted techniques. Therefore, this study aimed to describe a novel arthroscopic technique that anatomically reconstructs the posterolateral corner of the knee joint. This novel arthroscopic technique can properly identify important landmarks for reconstruction and anatomically reconstruct the three key components (lateral collateral ligament, popliteus tendon, and popliteofibular ligament) of the posterolateral corner of the knee joint.

Korean Version of the Anterior Cruciate Ligament-Return to Sport after Injury Scale: Translation and Cross-cultural Adaptation.

BACKGROUND: To translate into Korean and culturally adapt the anterior cruciate ligament-return to sports after injury (ACL-RSI) scale assessing psychological readiness to return to sports after ACL reconstruction and to validate its psychometric properties. METHODS: The ACL-RSI scale was forward translated into Korean and back-translated into English for cultural adaptation according to the standardized guideline. For validation, the Korean version of the ACL-RSI (ACL-RSI Kr) was administered to patients who underwent ACL reconstruction. The following subjective questionnaires were also administered: International Knee Documentation Committee Subjective Knee Evaluation Form (IKDC-SKF), Lysholm scale, Knee injury and Osteoarthritis Outcome Score (KOOS), and a Return to Sports Questionnaire. Test-retest reliability, internal consistency, content validity, construct validity, and discriminant validity of the ACL-RSI Kr were assessed. RESULTS: A total of 129 patients (102 men and 27 women) were included in the study. Their mean age was 28.3 years. The average follow-up duration was 13.2 months. Test-retest reliability was remarkable (intraclass correlation coefficient, 0.949), internal consistency was high (Cronbach's alpha, 0.932), and floor and ceiling effects were confirmed to be less than 10%. Construct validity assessed by correlation analysis with KOOS, IKDC-SKF, and Lysholm scale showed the correlation coefficients ranging from 0.169 to 0.679 (all p < 0.01). Compared with the Return to Sports Questionnaire, statistically significant difference was found in the ACL-RSI Kr between patients who received more than 7 points and less than 7 points (72.2 vs. 60.3, p = 0.025) for performance level scored using a 10-point Likert scale, proving its discriminative value. CONCLUSIONS: The ACL-RSI Kr demonstrated good psychometric properties. This scale can be an excellent instrument for evaluating patient's psychological readiness to return to sports after ACL injury.

High incidence of subsequent re-operation following treatments for medial meniscus tears combined with anterior cruciate ligament reconstruction: second-look arthroscopic study.

BACKGROUND: The Multicenter Orthopaedic Outcomes Network (MOON) group recently reported that medial meniscus (MM) repairs are associated with more frequent re-operations when compared to lateral meniscus (LM) repairs. The purpose of this study was to compare the meniscal healing and the incidence of subsequent re-operation of medial and lateral meniscal tears that occurred concurrently with anterior cruciate ligament (ACL) injuries. METHODS: We retrospectively reviewed patients who underwent second-look arthroscopy after primary ACL reconstruction (ACLR) between June 2005 to December 2016. The healing of meniscal tears following repair or left in situ, and re-tear following partial meniscectomy, were evaluated via second-look arthroscopy and compared between medial and lateral meniscus. Moreover, the incidence of subsequent meniscal re-operation after the index ACLR were investigated and compared between medial and lateral meniscus. Subsequent meniscal re-operation was performed in cases of the following three symptomatic meniscus tears: re-tears at the meniscectomy site; new tears; and failed healing of repaired or left in situ meniscus. RESULTS: There were 148 meniscal tears in 121 patients at index ACLR. There were 62 MM tears, 38 LM tears, and 24 bilateral meniscus tears. At second-look arthroscopy, the "successful healing" rate for tears following repair was higher in LM tears (91.2%) compared to MM tears (80.0%), although it was not statistically significant (p > 0.05). No significant differences were observed in the healing of left in situ tears or re-tear of meniscectomy site between medial and lateral meniscus. Patients with MM tears combined with ACL injuries had a higher incidence of subsequent meniscal re-operation compared to patients with LM tears (25.6% vs 16.1%, p = 0.025). CONCLUSIONS: There was a trend for the successful healing rate to be higher in LM repairs than MM repairs. Subsequent meniscal re-operations after ACLR were more frequent in patients with medial meniscal tears concurrently with ACL injuries in comparison to patients with lateral meniscal tears. LEVEL OF STUDY: Level IV, retrospective case series.

Regeneration of lateral discoid meniscus after arthroscopic partial meniscectomy in an adult patient.

Arthroscopic partial resection is indicated for patients who have symptomatic discoid meniscus with overall satisfactory clinical outcomes. Reports regarding regeneration of discoid meniscus after arthroscopic surgery are limited. There are only two reports for children in the literature. To the authors' knowledge, the present study is the first report in the literature to report regeneration of discoid lateral meniscus after arthroscopic partial meniscectomy in an adult patient. The diagnosis was confirmed by both magnetic resonance imaging and arthroscopy. Surgeons should be aware that regeneration of discoid meniscus can occur in adult as well as pediatric patients.Level of evidence V.

Hamstring autograft maturation is superior to tibialis allograft following anatomic single-bundle anterior cruciate ligament reconstruction.

PURPOSE: Using second-look arthroscopy, graft maturation was investigated and compared between hamstring (HA) autografts and tibialis anterior (TA) allografts after anatomic single-bundle anterior cruciate ligament reconstruction (ACLR). METHODS: Fifty-six patients who underwent second-look arthroscopy after anatomic single-bundle ACLR with either HA autografts (26, HA group) or TA allografts (30, TA group) from 2007 to 2016 were retrospectively reviewed. Graft maturation on second-look arthroscopy was evaluated in terms of four parameters: graft integrity (tear), synovial coverage, graft tension, and graft vascularization. Each parameter received a maximum of two points, depending on the status of the reconstructed graft. The total graft maturation score was calculated as the sum of the parameter scores. The total graft maturation and individual parameter scores were compared between the two groups. RESULTS: The mean time from ACLR to second-look arthroscopy was 22.5 ± 7.8 months. The maturation scores in the HA group were significantly better in terms of graft integrity (p = 0.041), graft tension (p = 0.010), and graft vascularization (p = 0.024), whereas the graft synovial coverage score was not significantly different. The total graft maturation score of the HA group was significantly higher than that of the TA group (6.3 ± 0.4 vs. 4.9 ± 0.3, p = 0.013). CONCLUSIONS: This study shows the superior graft maturation of HA autografts compared with that of TA allografts at a mean follow-up of 22.5 ± 7.8 months after anatomic single-bundle ACLR. When anatomic ACLR using soft tissue graft is planned, HA autograft is recommended rather than soft tissue allograft, especially in young and active patients. LEVEL OF EVIDENCE: Retrospective cohort review, Level III.