Clinical Relevance of Posterior Osteophyte Formation in Ultra-congruent Total Knee Arthroplasty: Midterm Radiographic Rollback and Impingement Analysis.

Background: Posterior femoral condylar osteophytes were frequently observed in patients with the ultra-congruent (UC) deep-dish design prosthesis. Therefore, the purpose of the present study was to verify the clinical relevance of osteophyte formation in the UC design. Methods: From March 2014 to February 2018, a comparative study was conducted on 96 knees using the UC design. They were divided into 2 groups (group 1: osteophyte +, group 2: osteophyte -). Intraoperative findings, indirect femoral rollback assessment using 30° flexion and active full flexion lateral radiographs, serial change of the osteophyte, and outcomes were compared. Results: The mean follow-up period was 49.35 ± 3.47 months in group 1 and 47.52 ± 3.37 months in group 2. Posterior component coverage was significantly different between the groups: group 1 exhibited more underhang and group 2 exhibited more overhang (p = 0.022). On the indirect assessment of the femoral rollback, there was a statistically significant difference in deep flexion and change in distance (p < 0.001 and p < 0.001, respectively). There was no statistical difference between the 2 groups in the American Knee Society knee and function score, and group 2 showed significant improvement in pain compared to group 1 in Western Ontario and McMaster University Arthritis Index pain score (p = 0.029). Conclusions: Posterior condylar osteophyte formation was related to posterior impingement. It was more frequently observed in the underhang of the femoral component and insufficient femoral rollback. In addition, it changed with time and caused negative effects, including a gradual decrease in flexion and more pain.

Age and medial compartmental OA were important predictors of the lateral compartmental OA in the discoid lateral meniscus: Analysis using machine learning approach.

PURPOSE: The objective of this study was to develop a machine learning model that would predict lateral compartment osteoarthritis (OA) in the discoid lateral meniscus (DLM), from which to then identify factors contributing to lateral compartment OA, with a key focus on the patient's age. METHODS: Data were collected from 611 patients with symptomatic DLM diagnosed using magnetic resonance imaging between April 2003 and May 2022. Twenty features, including demographic, clinical and radiological data and six algorithms were used to develop the predictive machine learning models. Shapley additive explanation (SHAP) analysis was performed on the best model, in addition to subgroup analyses according to age. RESULTS: Extreme gradient boosting classifier was identified as the best prediction model, with an area under the receiver operating characteristic curve (AUROC) of 0.968, the highest among all the models, regardless of age (AUROC of 0.977 in young age and AUROC of 0.937 in old age). In the SHAP analysis, the most predictive feature was age, followed by the presence of medial compartment OA. In the subgroup analysis, the most predictive feature was age in young age, whereas the most predictive feature was the presence of medial compartment OA in old age. CONCLUSION: The machine learning model developed in this study showed a high predictive performance with regard to predicting lateral compartment OA of the DLM. Age was identified as the most important factor, followed by medial compartment OA. In subgroup analysis, medial compartmental OA was found to be the most important factor in the older age group, whereas age remained the most important factor in the younger age group. These findings provide insights that may prove useful for the establishment of strategies for the treatment of patients with symptomatic DLM. LEVEL OF EVIDENCE: Level III.

Development of a machine learning model for identifying the optimal situation favoring double-level osteotomy over single-level high tibial osteotomy.

BACKGROUND: This study aimed to develop a machine learning (ML) model to identify the optimal situation wherein double-level osteotomy (DLO) is favored for severe varus knees by analyzing unfavorable outcomes. This study hypothesized that there are the most favorable algorithms and contributing factors for identifying the optimal situation favoring DLO over opening-wedge high tibial osteotomy (OWHTO). METHODS: Data were retrospectively collected from patients who underwent OWHTO (505 knees). Unfavorable outcome parameters were defined as follows: (1) medial proximal tibial angle (MPTA) > 95°, (2) joint line convergence angle (JLCA) > 4° (insufficient medial release), (3) JLCA < 0° (medial instability), (4) recurrence of varus deformity, and (5) lateral hinge fracture. The input data for the ML model included demographic data and preoperative radiological and intra-operative factors. The ML model was used to evaluate overall and to evaluate each unfavorable outcome. Interpretation by the model was performed by SHapley Additive exPlanations. RESULTS: The unfavorable group had a larger JLCA and MPTA preoperatively than the favorable group in the conventional comparison. The light gradient boosting machine (LGBM) demonstrated the highest AUC of 0.66 and F-1 score of 0.72 among the ML algorithms. In the overall assessment, the preoperative weight-bearing line ratio (WBLR) was the factor that contributed the most, followed by the preoperative JLCA and the ΔWBLR. ΔWBLR and the preoperative JLCA were the contributing factors for each outcome. CONCLUSIONS: The LGBM model was superior in predicting the optimal situations favoring DLO over OWHTO. Preoperative WBLR, preoperative JLCA, and ΔWBLR significantly contributed to the unfavorable outcomes overall and for each outcome in the ML model.

Postoperative Intravenous Iron Supplementation Increases Hemoglobin Level in Total Knee Arthroplasty.

Iron supplementation provides iron storage and facilitates effective production of hemoglobin. The purpose of this study was to investigate the effect of early postoperative intravenous (IV) iron supplementation in different types of total knee arthroplasty (TKA) surgery. We retrospectively analyzed 863 patients who underwent TKA between September 2017 and September 2021. The IV iron (I) and non-IV iron (NI) groups were compared. Hemoglobin responders, defined as patients who showed a change in hemoglobin level of ≥2 g/dL at 6 weeks of surgery compared to the baseline immediate postoperative hemoglobin level, were identified and they were compared with the nonresponders. After logistic regression analysis, the patients were classified according to the type of surgery (unilateral TKA, staged bilateral TKA, and simultaneous bilateral TKA). A subgroup analysis was performed according to the comorbidity as Charlson Comorbidity Index (CCI). The type of surgery and the rate of hemoglobin responders differed between the I and NI groups. The surgery type and iron supplementation significantly affected the hemoglobin responder in the logistic regression model. In each surgery type, hemoglobin drop in the I group was generally lower in the second and sixth weeks than that in the NI group. It was also effective in reducing hemoglobin drop on the first day of the second surgery in staged bilateral TKA. In addition, the number of hospital days was lower in the IV iron supplementation group who underwent a staged bilateral TKA. CCI did not affect hemoglobin responder, hemoglobin drop, and transfusion rate in both the I and NI groups. Postoperative IV iron supplementation affected the outcome of hemoglobin responders. In addition, it reduced early postoperative hemoglobin drop. However, iron supplementation did not affect the transfusion rate, complications, and clinical outcome, regardless of the type of surgery. LEVEL OF EVIDENCE: Level III, case-control study.

Retro-tubercular Biplanar Medial Opening-Wedge High Tibial Osteotomy Results in Superior Patellofemoral Alignment Versus Supra-tubercular Osteotomy.

PURPOSE: To compare the changes in patellofemoral (PF) joint alignment, focusing on multiple planes, between two different types of biplanar medial opening-wedge high tibial osteotomy (OWHTO). METHODS: Patients who underwent biplanar OWHTO between July 2017 and May 2021 were retrospectively evaluated. They were allocated to either the supra-tubercular (ST)- or retro-tubercular (RT)-OWHTO group. The following radiologic parameters were compared between the two groups: 1) weight-bearing line ratio (WBLR), 2) patellar height, 3) posterior tibial slope (PTS), 4) tibial tubercle-trochlear groove (TT-TG) distance, 5) TT-TG angle, and 6) femoral shaft-patellar tendon (FS-PT) angle. Clinical outcomes and the minimal clinically important difference (MCID) were also evaluated. RESULTS: In total, 104 knees that underwent ST-OWHTO and 105 knees that underwent RT-OWHTO were evaluated. The patellar height significantly decreased only after ST-OWHTO (P < .001). The TT-TG distance and FS-PT angle significantly increased, more after ST-OWHTO than RT-OWHTO (mean change value: 5.72 mm vs 1.91 mm; P < .001 for TT-TG distance; and 4.72° vs 1.80°; P < .001 for FS-PT angle). The TT-TG angle increased significantly after ST-OWHTO (mean change value: 7.62°; P < .001) but decreased after RT-OWHTO mean change value: -4.30°; P < .001). The PTS more increased after RT-OWHTO than after ST-OWHTO (mean change value: 0.91° vs 1.69°; P = .003). Clinical outcomes in both groups improved postoperatively, and no significant differences were observed between the groups. CONCLUSIONS: RT-OWHTO resulted in lesser changes in multiplane PF joint alignment than ST-OWHTO. However, no difference was observed in clinical outcomes between both groups, and PTS increased after RT-OWHTO. Therefore, these aspects of RT-OWHTO should also be considered. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Arthroscopic Meniscal Repair and Meniscectomy for Adult Discoid Lateral Meniscus Results in Progression to Valgus Alignment and Lateral Compartment Degeneration Compared With Nonoperative Treatment and Nondiscoid Lateral Meniscus.

PURPOSE: To analyze the effect of the arthroscopic meniscal procedure in adult discoid lateral meniscus (DLM) according to the age and meniscal-preserving by making comparisons with the nondiscoid lateral meniscus (N-DLM). METHODS: From March 2014 to October 2020, a comparative analysis was performed in adults with DLM who underwent arthroscopic meniscal procedures (operative DLM: 134 knees), nonoperative treatment (nonoperative DLM: 56 knees), and adult N-DLM who underwent arthroscopic meniscal procedures (operative N-DLM: 64 knees). These patients were between 20 and 65 years old and completed a minimum follow-up of 2 years. Patients with DLM who underwent arthroscopic procedure were divided into subgroups according to age and extent of the meniscal-preserving. The following parameters were assessed and compared between the groups: (1) coronal limb alignment, (2) osteoarthritis grade, and (3) clinical outcomes and the minimal clinically important difference. RESULTS: The coronal limb alignment was significantly changed to valgus in the order of operative DLM, N-DLM, and nonoperative DLM (Δ mechanical hip-knee-ankle angle: 3.23 ± 1.85 vs 1.35 ± 1.03° vs -0.57 ± 1.88°; P < .05). Operative DLM showed most prominent osteoarthritic change in the lateral compartment, followed by the N-DLM and nonoperative DLM groups (40.3% vs 17.2% vs 5.3%; P < .05). These changes in operative DLM were more prominent in older adults who underwent meniscal-sacrificing procedures and resulted in less-satisfactory clinical outcomes (all P < .05). CONCLUSIONS: Arthroscopic surgery for adult DLM resulted in progression to valgus alignment and lateral compartment degeneration compared with nonoperative treatment and arthroscopic surgery of the adult N-DLM. Old ager and having a meniscal-sacrificing procedure showed more rapid radiographic changes and lower clinical outcomes. LEVEL OF EVIDENCE: Level III, retrospective comparison study.

Maintenance of the joint line and posterior condylar offset are the most notable variables for successful outcomes of revision total knee arthroplasty.

INTRODUCTION: Controversy regarding which variables should be prioritized for better outcomes in revision total knee arthroplasty (RTKA) exists. This study aimed to comprehensively analyze the variables affecting RTKA outcomes. MATERIALS AND METHODS: We retrospectively identified 87 RTKAs in 82 patients who were performed between March 2014 and February 2020. Range of motion (ROM), including flexion contracture (FC) and further flexion (FF), was analyzed according to the covariates. The covariates included mode of failure, joint line position, anteroposterior (AP) position, rotational alignment of the femoral component, and patellofemoral alignment. The differences between the final follow-up values of each RTKA variable and those of the native knee were evaluated. The clinical outcomes were evaluated. RESULTS: No significant differences were observed between the joint line positions of the RTKA and native knees. The patellar and AP positions of the femoral component were restored to pre-TKA values. The femoral component had an external rotation of 2.78° compared with the native knee. In multivariable stepwise regression analysis, restoration of the adductor tubercle joint line and posterior condylar offset (PCO) were significant variables affecting ROM. Septic RTKA (33 knees) resulted in poor FF outcomes (p = 0.030) and Western Ontario and McMaster Universities Osteoarthritis Index stiffness (WOMAC S) scores (p < 0.001), compared with aseptic RTKA (54 knees). CONCLUSIONS: Restoration of the joint line position and PCO are crucial factors for improved ROM in RTKA. Joint line elevation in RTKA resulted in worse ROM than joint line lowering. In addition, RTKA due to septic failure had inferior ROM and WOMAC S scores compared with RTKA due to aseptic failure. LEVEL OF EVIDENCE: Level III, cohort study.

Constitutional alignment predicts medial ligament balancing in mechanically aligned total knee arthroplasty for varus knees.

PURPOSE: The aim of this study was to identify if constitutional alignment and preoperative radiologic parameters determined whether medial gap balancing was required in mechanically aligned total knee arthroplasty (TKA). METHODS: Two hundred and sixty three patients with 394 consecutive knees who underwent primary TKAs were retrospectively analysed in this study. Selective sequential multiple needle puncturing (MNP) was performed for medial ligament balancing when required. Constitutional alignment, which was determined using the Coronal Plane Alignment of the Knee (CPAK) classification, as well as preoperative and postoperative radiologic parameters was evaluated to identify factors which predicted the need for MNP. RESULTS: One hundred and fifty eight (40.1%) knees required medial ligament balancing with MNP. Patients who required MNP during surgery had significantly more constitutional varus, more varus preoperative mechanical Hip-Knee-Ankle angle (mHKA), smaller preoperative medial proximal tibial angle (MPTA) and a larger change in mHKA and MPTA after surgery than those who did not. Patients with constitutional varus also had a higher incidence of having had MNP to both anterior and posterior superficial medial collateral ligament (sMCL) fibres. There was no significant difference in preoperative lateral distal femoral angle (LDFA), posterior tibial slope (PTS) and varus-valgus difference (VVD) between groups. CONCLUSION: Ligament balancing using MNP was determined by constitutional alignment rather than medial soft tissue contracture. Patients with constitutional varus who had a larger medio-lateral gap difference in extension also had a higher incidence of having had MNP to both anterior and posterior sMCL fibres. LEVEL OF EVIDENCE: Retrospective comparative study, level IV.

Prior tuberosity screw fixation of the osteotomized tubercle can lead to favorable outcomes in retro-tubercular bi-planar opening wedge high tibial osteotomy.

BACKGROUND: Exact information regarding fixing the tuberosity screw during retro-tubercular opening-wedge high tibial osteotomy (RT-OWHTO) is still lacking. The purpose of this study was to determine whether prior tuberosity screw fixation before plate fixation of main osteotomy fragment can prevent complications associated with tuberosity screw. METHODS: From 2019 to 2021, patients who underwent RT-OWHTO were divided into two groups (group I, prior tuberosity screw fixation; group II, later tuberosity screw fixation). A total of 49 and 44 knees were included in groups I and II, respectively. Plain radiographs and computed tomography (CT) were used to analyze the parameters of tuberosity screw fixation, neurovascular (NV) safety and osteotomy configurations. Clinical outcomes and post-operative complications were assessed. RESULTS: The delta (Δ) of the deformation angle of the tuberosity (P = 0.002), delta (Δ) of the posterior tibial slope (PTS) (P < 0.001), extruded screw length (P < 0.001), and retro-tuberosity tip distance (P < 0.001) of group I were significantly smaller than those of group II. All tuberosity screws were fixed medially to the NV structures. Post-operative tuberosity fracture occurred in one knee (2%) in group I and in 10 knees (23%) in group II (P = 0.003). CONCLUSIONS: RT-OWHTO with prior tuberosity screw fixation can minimize the risk of tuberosity fracture and an increase in the PTS. It can also prevent NV injuries by reducing extruded tuberosity screw length and fixing it medially from the NV structures.

Constitutional and postoperative joint line obliquity can predict serial alignment change after opening-wedge high tibial osteotomy: analysis using coronal plane alignment of the knee classification.

PURPOSE: The purposes of this study were (1) to clarify the distribution of the Coronal Plane Alignment of the Knee (CPAK) phenotype in patients who underwent medial opening-wedge high tibial osteotomy (OWHTO) and (2) to identify the predictive factors for postoperative serial alignment changes after OWHTO by analyzing constitutional phenotypes. METHODS: Patients who underwent OWHTO between March 2014 and December 2019 were retrospectively evaluated. Those who completed a minimum follow-up of 3 years were divided into three groups based on the direction of alignment changes from postoperative 3 months to the final follow-up: Group 1 (varus direction) when the weight-bearing line ratio (WBLR) change was less than - 4%, Group 2 (maintained) when the WBLR change was between - 4% and 4%, and Group 3 (valgus direction) when the WBLR change was greater than 4%. The following parameters were assessed serially and compared between the groups: (1) radiologic parameters of coronal limb alignment such as joint line obliquity (JLO), (2) CPAK phenotypes, and (3) clinical outcomes. RESULTS: In total, 163 knees were included, and the average duration of follow-up was 4.8 ± 1.6 years. More apex distal JLO was observed in the order of Group 1, 2, and 3 at all times (all p < 0.05). The most common CPAK type was type (I + II) (constitutional: apex distal JLO) + type (V + VI) (postoperative 3 months: neutral JLO) in Group 1 (29.4%; p = 0.000); otherwise, the most common CPAK type was type (IV + V) (constitutional: neutral JLO) + type (VIII + IX) (postoperative 3 months: apex proximal JLO) in Group 3 (11.7%; p = 0.000). Clinical outcomes did not differ between the groups. CONCLUSION: Constitutional and postoperative JLO were predictive factors of postoperative alignment changes after OWHTO. Constitutional apex distal and postoperative neutral JLO had a tendency for varus alignment progression, whereas constitutional neutral and postoperative apex proximal JLO had a tendency for valgus alignment progression. LEVEL OF EVIDENCE: Retrospective cohort study; Level III.

Does referencing system affect the selection of implant size, position and gap balance in total knee arthroplasty?

BACKGROUND: (1) To evaluate if referencing system affects selection of implant size, position, and gap balance in total knee arthroplasty (TKA) with the use of contemporary implant designs and (2) to describe the authors' intraoperative sizing strategy using anterior referencing (AR) and posterior referencing (PR) systems. METHODS: This was a retrospective review of 270 consecutive patients (397 knees) who underwent primary TKA with an AR or PR system. Selection of implant size, mediolateral and anteroposterior alignment of the femoral component, as well as gaps were compared between groups. RESULTS: In the AR group, more patients had femoral components which were upsized or downsized compared to those in the PR group (29.5% vs 12.0% respectively) and in patients who underwent bilateral TKA, 49.4% of those in the AR group had femur component size asymmetry. The AR group had better medio-lateral (ML) fit over the distal cutting surface area, smaller change in anterior offset but higher incidence of anterior notching when compared to the PR group. Posterior condylar offset (PCO) was restored in both groups and gap differences in flexion-extension and ML were comparable. There was also no difference in clinical scores and ROM between groups at 2-years follow-up. CONCLUSION: In this study, conventional implications related to referencing system were not observed. In practice, AR systems can restore PCO while PR systems do not result in increased anterior notching or anterior overstuffing. Differences observed in this study are most likely related to implant design specifics and surgical technique.

The use of an anatomic tibial baseplate in total knee arthroplasty optimizes coverage without compromising rotation: A propensity-matched evaluation.

BACKGROUND: The aims of this study were (1) to compare in vivo coverage and rotational alignment of 2 tibial component designs: anatomic and symmetrical; and (2) to determine if coronal deformity and tibial torsion were related to rotation and coverage. METHODS: Postoperative CT scans of 200 propensity score-matched patients who underwent TKA with either an anatomic (ATC) or symmetrical tibia component (STC) were analyzed. Rotation was measured using four axes: surgical transepicondylar axis (sTEA), Berger's protocol, medio-lateral (ML) axis and posterior borders of the tibial plateau, while coverage was assessed by measuring fit and surface area. The relationship between coronal deformity, tibial torsion, rotation, and coverage was investigated. RESULTS: Overall, STCs had more internal rotation when measured using the sTEA (-0.6° ± 3.5 vs 0.5° ± 3.6, p = 0.03), Berger's protocol (-21.6° ± 7.1 vs -17.9° ± 6.2, p = 0.000) and ML axes (2.9° ± 3.9 vs 8.1° ± 5.1, p = 0.000) compared to ATCs. STCs also had more posteromedial underhang (-3.3 mm ± 2.4 mm vs -1.7 mm ± 2.5 mm, p = 0.000) but smaller change in tibial torsion postoperatively (-18.4° ± 9.9° vs -13.1° ± 9.4°, p = 0.000). Tibial torsion was more pronounced in valgus than varus knees both preoperative (-25.4° ± 6.5° vs -20.2° ± 9.3°, p = 0.02) and postoperatively (-19.7° ± 7.2° vs -14.7° ± 10.3°, p = 0.04), but there was no difference in postoperative tibial torsion between ATCs and STCs in this subgroup. CONCLUSION: The use of an anatomic tibial baseplate optimizes coverage by reducing posterolateral overhang and posteromedial underhang. It also achieved better rotational profiles compared to STCs. However, it resulted in a larger change in tibial torsion after TKA.

The development of machine learning algorithms that can predict patients satisfaction using baseline characteristics, and preoperative and operative factors of total knee arthroplasty.

BACKGROUND: Patient satisfaction following primary total knee arthroplasty (TKA) is a crucial part to evaluate the success of the procedure. The purpose of this study was to develop to predict patient satisfaction following TKA. METHODS: Satisfaction outcome data after 435 consecutive conventional TKAs performed between August 2020 and December 2021 were retrospectively collected. The total 26 input data were collected. The most favorable algorithm was first found using logistic regression (LR) and machine learning (ML) algorithms. To evaluate the predictive performance of the models, both area under curve (AUC) and F1-score were used as the primary metrics. The shapley additive explanations (SHAP) feature explanation in XGBoost and LR analysis were performed to interpret the model. RESULTS: The performance of extreme gradient boosting classifier (XGBoost) was only higher than that of conventional LR in AUC (0.782 vs. 0.689). Comparing the F-1 score, only XGBoost showed better performance than LR (0.857 vs. 0.800). The most predictive feature in XGBoost was Short Form-36 physical and mental component summary scores (SF-36 MCS), followed by Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain, Bone mineral density (BMD). In the LR analysis, lumbar spine disease, WOMAC pain, and BMD were statistically significant. CONCLUSION: XGboost showed the best performance and was superior to conventional LR in the prediction of patient satisfaction after TKA. The SF-36 MCS was the most important feature in the ML model. WOMAC pain and BMD were meaningful variables and demonstrated a linear relationship with satisfaction in both the LR and ML models. LEVEL OF EVIDENCE: Retrospective cohort study; Level of evidence 3.

Outcomes of Distal Medial Collateral Ligament Release During Opening-Wedge High Tibial Osteotomy.

Background: During opening-wedge, high-tibial osteotomy (OWHTO), various methods of managing the superficial medial collateral ligament (sMCL) can be performed to obtain a sufficient medial side opening. Purpose/Hypothesis: The purpose of this study was to evaluate the outcomes of distal sMCL release during OWHTO. It was hypothesized that distal sMCL release would not cause valgus instability. Study Design: Case series; Level of evidence, 4. Methods: This retrospective study included 77 patients who underwent OWHTO between January 1, 2018, and October 31, 2019, and completed serial radiological assessments including weightbearing line ratio (WBLR), medial proximal tibial angle (MPTA), coronal translation, total tibial plateau inclination (TTPI), valgus medial joint-space width (valgus-MJSW), valgus joint-line convergence angle (valgus-JLCA), varus lateral joint-space width (varus-LJSW), and varus joint-line convergence angle (varus-JLCA) on standing whole-leg and varus-valgus stress radiographs. Subgroup analysis of pre- to postoperative changes in radiologic parameters was performed according to TTPI (group 1: <25th percentile, group 2: 25th-75th percentile, group 3: >75th percentile) and Ahlbäck osteoarthritis classification (group 1: Ahlbäck grade 1, group 2: Ahlbäck grades 2 and 3). Results: The mean time to final follow-up was 34.6 ± 6.4 months. The WBLR and coronal translation did not change significantly over the follow-up period. The valgus-MJSW at 6 months postoperatively was significantly wider than that preoperatively and at 1 year postoperatively (P < .001). The varus-LJSW at 6 months postoperatively was significantly wider compared with preoperatively and 1 year postoperatively (P < .001), and the varus-LJSW at 1 year postoperatively was wider than that found preoperatively. Coronal translation was significantly more reduced for patients in TTPI group 1 versus group 3 (P = .019). There was no significant differences according to the Ahlbäck groups. All clinical outcomes improved at final follow-up compared with preoperative values (P ≤ .002). Conclusion: The study findings indicated that sMCL release did not cause valgus instability or valgus overcorrection at 1 year postoperatively, and improved clinical outcomes were seen at the final follow-up compared with preoperative status after OWHTO with sMCL release.

Association Between Tunnel Position, Tunnel Angle, Graft Signal Intensity, and Graft Thickness in the Reconstructed Posterior Cruciate Ligament.

Background: An appropriate tunnel position, tunnel angle, and tunnel-graft angle are important factors for maintaining the stability and mechanical properties of a posterior cruciate ligament (PCL) graft. Purpose: To evaluate the association between tunnel position, tunnel angle, graft signal intensity ratio (SIR), and graft thickness after remnant-preserving PCL reconstruction. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Included were patients who had undergone remnant-preserving single-bundle PCL reconstruction using a tibialis anterior allograft between March 2014 and September 2020 and who had minimum 12-month postoperative magnetic resonance imaging scans. Tunnel position and angle were evaluated via 3-dimensional computed tomography, and their association with graft SIR on both the femoral and the tibial sides was determined. Graft thickness and SIR at 3 areas of the graft were evaluated and compared, and their association with tunnel-graft angle was also determined. Results: Overall, 50 knees (50 patients; 43 male, 7 female) were included. The mean time to postoperative magnetic resonance imaging was 25.8 ± 15.8 months. The mean SIR of the graft's midportion was higher compared with that of the proximal and distal portions (P = .028 and P < .001, respectively), and the SIR of the proximal portion was higher compared with that of the distal portion (P = .002). The femoral tunnel-graft angle was more acute than the tibial tunnel-graft angle (P = .004). A more anteriorly and distally located femoral tunnel led to a less acute femoral tunnel-graft angle (P = .005) and a decreased SIR of the proximal portion (P = .040), and a more laterally located tibial tunnel was associated with a less acute tibial tunnel-graft angle (P = .024) and a reduced SIR of the distal portion (P = .044). The mean thicknesses of the graft's midportion and distal portion were larger than that of the proximal portion (P < .001). The SIR of the graft's midportion was positively correlated with its thickness (r = 0.321; P = .023). Conclusion: The SIR of the proximal portion of the graft around the femoral tunnel was higher than that of the distal portion around the tibial tunnel. An anteriorly and distally positioned femoral tunnel and a laterally positioned tibial tunnel resulted in less acute tunnel-graft angles that were associated with decreased signal intensity.

Clinical relevance of roll-back replacement of ultra congruent total knee arthroplasty: comparison of mid-term outcomes with posterior stabilizing design.

INTRODUCTION: The outcomes of total knee arthroplasty (TKA) remain controversial, and we do not know which factors are important for successful outcomes. This study aimed to compare the mid-term outcomes of different conceptual designs by evaluating the radiological and clinical outcomes. MATERIALS AND METHODS: A total of 478 total knee arthroplasties (TKAs) were enrolled and allocated into groups I [posterior stabilizing (PS) with anterior referencing (AR)], II [PS with posterior referencing (PR), and III [ultra-congruent (UC) TKA)]. Preoperative findings, last follow-up clinical outcomes, and final follow-up radiological and indirect assessments of the femoral rollback were compared between the groups. RESULTS: The mean follow-up period was 72.6 ± 12.9 months. The tourniquet was used samely applied to every group. Flexion contracture was significantly larger in group III than in groups I and II (3.3 ± 2.7, p < 0.001), and further flexion was significantly smaller in group III (130.0° ± 2.7°, p < 0.001). Among the radiological parameters, posterior osteophyte formation was the most common in group III (67.8%). The rollback distance was significantly smaller in group III than in groups I and II (p < 0.001). The active deep flexion angle was affected by the posterior condylar offset (PCO) ratio, and the contact point changed the distance (p < 0.05). CONCLUSION: PS TKAs showed better ROMs than UC TKAs; however, no differences were noted in the clinical outcome scales. The flexion angle was affected by the PCOR and rollback at both PS and UC TKAs. However, rollback negatively affected the flexion angle during UC TKAs. An inappropriate femoral rollback was identified, and femoral osteophyte formation was determined to be the most prominent in UC TKAs. Level of evidence Level III comparative study.

Graft impingement increases anterior cruciate ligament graft signal more than acute graft bending angle: magnetic resonance imaging-based study in outside-in anterior cruciate ligament reconstruction.

PURPOSE: In this study, the relationship between patient-specific geometric factors and tunnel placement in graft impingement was identified by using magnetic resonance imaging (MRI) signal intensity of anterior cruciate ligament (ACL) grafts. METHODS: Ninety-two patients, who were treated between 2014 and 2020, were included retrospectively. These patients underwent primary remnant-preserving outside-in ACL reconstruction (ACLR) and were followed up with postoperative MRI at least one year after surgery. Plain radiographs and computed tomography (CT) were used to analyze tibial and femoral tunnel positions. Postoperative MRI was performed, at 32.8 ± 17.5 months after surgery, to evaluate the graft signal intensity, the ACL/posterior cruciate ligament (PCL) ratio (APR), ACL/muscle ratio (AMR), tunnel positions, and graft impingement. Clinical and stability outcomes were analyzed using the International Knee Documentation Committee (IKDC) subjective and objective scores, Lysholm scores, and side-to-side differences (SS-D). RESULTS: The mean APR and AMR of the proximal third of the grafts were significantly lower than those of the middle third of the grafts (p = 0.017 and p = 0.045, respectively). Multivariate regression analysis showed that there was a negative association between the mean APR and AMR of entire intra-articular ACL graft and the distance from the anterior end of the intercondylar roof to the center of the tibial tunnel in the sagittal plane (p < 0.001 and p < 0.001, respectively) and the notch width index (p < 0.001 and p = 0.002, respectively). No significant correlations were found between tunneling and geometric factors, and clinical scores or SS-D. CONCLUSIONS: Graft impingement on the anterior tibial tunnel relative to the end of the intercondylar roof and narrow notch was a more significant contributing factor on increased signal intensities of the ACL graft, compared with the acute femoral bending angle in remnant-preserving outside-in ACLR. Therefore, surgeons should focus on intercondylar notch anatomy during tibial tunnel placement to avoid roof impingement. LEVEL OF EVIDENCE: Level III.

Preoperative education on realistic expectations improves the satisfaction of patients with central sensitization after total knee arthroplasty: a randomized-controlled trial.

PURPOSE: The aim of this study was to investigate whether an additional module on realistic expectations following total knee arthroplasty (TKA) would lead to a higher proportion of satisfied patients compared to existing preoperative education. METHODS: This was a single-center, randomized-controlled trial. A total of 172 patients who were scheduled for TKA between September 2020 and October 2021 were enrolled. Patients were randomized to receive either only standard preoperative education, or an additional module on realistic expectations following TKA. The primary outcome was patient satisfaction. Secondary outcomes were Short Form-36, Western Ontario and McMaster Universities Osteoarthritis Index, crepitus score, and range of motion. Subgroup analysis was performed based on central sensitization inventory (CSI) score stratification. Assessment was performed at the 3-month, 6-month, and > 1-year follow-up. RESULTS: At more than 1 year, 65/78 (83.3%) patients in the intervention group and 52/80 (65.0%) patients in the control group were satisfied (P = 0.03). The mean satisfaction score was measured as 4.2 ± 0.9 in the intervention and 3.9 ± 0.9 in the control at > 1 year (P = 0.01). There were significant differences in Short Form-36 physical and mental component summary scores and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and stiffness scores at 6 months (P = 0.02, P = 0.02, P = 0.04, P = 0.04). The frequency of satisfaction and mean satisfaction score in the top 25 percentile CSI group were 15/16 (93.8%) and 4.6 ± 0.6 in those who received intervention and 12/19 (63.2%) and 3.8 ± 0.8 in those who did not (P = 0.01, P = 0.01). CONCLUSIONS: Thorough preoperative education on realistic expectations following TKA showed effects on WOMAC pain and satisfaction at > 1 year after surgery. It was more prominent in the group with a higher CSI score at > 1-year follow-up. LEVEL OF EVIDENCE: Level I.

Postoperative rehabilitation using a digital healthcare system in patients with total knee arthroplasty: a randomized controlled trial.

INTRODUCTION: Digital healthcare systems based on augmented reality (AR) show promise for postoperative rehabilitation. We compared the effectiveness of AR-based rehabilitation and conventional rehabilitation after total knee arthroplasty (TKA). MATERIALS AND METHODS: We randomly allocated 56 participants to digital healthcare rehabilitation group (DR group) and conventional rehabilitation group (CR group). Participants in the CR group performed brochure-based home exercises for 12 weeks, whereas those in the DR group performed AR-based home exercises that showed each motion on a monitor and provided real-time feedback. The primary outcome was change in 4-m gait speed. The secondary outcomes were the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, health-related quality of life [assessed by the EuroQoL 5-Dimension 5-Level (EQ5D5L) questionnaire], pain [measured using a numeric rating scale (NRS)], Berg Balance Scale (BBS), range of motion (ROM), and muscle strength. Outcomes were measured at baseline (T0) and 3 (T1), 12 (T2), and 24 (T3) weeks after randomization. RESULTS: There was no significant difference in baseline characteristics of participants between two groups, except age and body mass index. No group difference was observed in 4-m gait speed (0.37 ± 0.19 and 0.42 ± 0.28 for the DR and CR groups, respectively; p = 0.438). The generalized estimating equation model revealed no significant group by time interaction regarding for 4-m gait speed, WOMAC, EQ5D5L, NRS, BBS, ROM, and muscle strength score. All outcomes were significantly improved in both groups (p < 0.001). CONCLUSION: The use of a digital healthcare system based on AR improved the functional outcomes, pain, and quality of life of patients after TKA. AR-based rehabilitation may be useful treatment as an alternative to conventional rehabilitation. TRIAL REGISTRATION: ClinicalTrials.gov (identifier: NCT04513353). Registered on August 9, 2020. http://clinicaltrials.gov/ct2/show/NCT04513353 .