Effects of an untreated medial meniscal ramp lesion on histological deterioration findings of the medial meniscus: A study in a porcine anterior cruciate ligament reconstruction model.

Purpose: To evaluate the effect of untreated medial meniscal ramp lesions (MMRLs) on the tendon graft after anterior cruciate ligament (ACL) reconstruction and histological findings of medial meniscus (MM) in a porcine a model. Methods: A total of 17 pigs were divided into two groups: (1) the untreated MMRL group (UM group, n = 9) and (2) intact MM group (n = 8) and euthanized 12 weeks after surgery. The specimens were then tested cyclically and loaded to failure. Side-to-side differences (SSDs) in translation under cyclic loading and structural properties were analyzed. Histological evaluation of the MM was also performed. Results: No significant differences in the SSD in translation during the cyclic testing (UM group, 0.3 ± 0.4 mm; intact MM group, 0.1 ± 1.4 mm), upper yield load (UM group, 476.3 ± 399.9 N; intact MM group, 643.2 ± 302.9 N), maximum load (UM group, 539.5 ± 265.8 N; intact MM group, 705.8 ± 282.6 N), linear stiffness (UM group, 63.5 ± 39.0 N/mm; intact MM group, 73.7 ± 60.1 N/mm) and elongation at failure (UM group, -4.6 ± 16.3 mm; intact MM group, 2.3 ± 6.6 mm) were observed. However, the UM group had significantly worse Modified Mankin's histological grading scores (1.8 ± 0.4 [1-2] vs. 0 ± 0 [0]; p < 0.001) and Modified Copenhaver classification scores (6.6 ± 2.4 [2-9] vs. 0.7 ± 1.1 [0-3]; p < 0.001) than did the intact MM group. Conclusion: Untreated MMRLs showed postoperative histological deterioration. Level of Evidence: Level IV.

Comparison of postoperative clinical outcome in medial-pivotal and gradually reducing radius design cruciate-retaining total knee arthroplasty-A multicenter analysis of propensity-matched cohorts.

Purpose: To clarify differences in surgery duration, postoperative knee range of motion (ROM), anterior and posterior (AP) laxity, and Forgotten Joint Score (FJS) in patients undergoing medial-pivot (MP) and GRADIUS cruciate-retaining (CR) total knee arthroplasty (TKA) surgeries. Methods: We examined patients who underwent either MP or CR TKA at six different Japanese centres. Patients were propensity score matched for age, sex, and preoperative hip-knee angle (HKA). We compared the groups' average surgery duration, postoperative knee ROM, AP laxity, and FJS 1 year after surgery. Results: There were 86 study patients: 43 MP and 43 CR TKA matched for age, sex, and preoperative HKA. The MP group enjoyed a significantly shorter surgery duration (89.1 ± 10.9 mins vs. 95.7 ± 12.0 mins, p = 0.0091) and significantly better postoperative knee flexion than the CR group (123.7 ± 9.1° vs. 115.3 ± 12.4°, p < 0.001). The MP had significantly smaller postoperative AP laxity with 30° of knee flexion than the CR group (3.4 ± 1.3 vs. 5.6 ± 2.2 mm, p < 0.001). Conversely, postoperative AP laxity with 90° of knee flexion was significantly larger for the MP group (3.6 ± 1.3 vs. 2.7 ± 1.9 mm, p = 0.0098). There were no between-group differences in postoperative FJS. Conclusions: The MP group showed better postoperative knee flexion, midrange AP knee stability, and shorter surgery duration. Level of Evidence: Level III, retrospective comparative study.

Posterior Displacement of Meniscal Ramp Lesion Is Observed on Flexed Knee Magnetic Resonance Imaging of Anterior Cruciate Ligament-Deficient Knees.

PURPOSE: To confirm whether posterior displacement of the detached meniscocapsular structure in ramp lesions could be observed on magnetic resonance imaging (MRI) in the flexed knee position and to clarify whether this displacement on MRI is related to greater anterior knee laxity. METHODS: This retrospective comparative trial study included 50 patients with anterior cruciate ligament injuries in whom attendant ramp lesions were observed on preoperative MRI. All patients underwent 3-T MRI at 120° of knee flexion preoperatively. The gap distance of the ramp lesion on sagittal slices was measured, and a distance greater than 1 mm was classified as gap positive. Additionally, joint effusion in the posteromedial recess was quantitatively evaluated by measuring the surface area of joint fluid. Prior to surgery, the side-to-side difference in anterior tibial translation (ATT) on stress radiographs at 20° of knee flexion was measured to evaluate anterior knee laxity. During anterior cruciate ligament reconstruction, the length of the ramp lesion was measured by a scale from the posteromedial portal. RESULTS: Of the 50 knees, 29 had ramp lesion gaps greater than 1 mm on MRI at knee flexion. The gap-positive group had a significantly greater side-to-side difference in ATT (9.6 ± 3.6 mm vs 5.0 ± 2.7 mm, P < .001) and significantly larger ramp lesion length (15.7 ± 4.9 mm vs 11.7 ± 3.9 mm, P = .002) than the gap-negative group. The gap-positive group also had a significantly greater amount of joint effusion than the gap-negative group (P < .001). CONCLUSIONS: Posterior displacement of the detached meniscocapsular structure in ramp lesions can be observed on MRI at knee flexion and is related to greater anterior knee laxity, lesion size, and joint effusion. LEVEL OF EVIDENCE: Level III, retrospective comparative trial.

Association between intraoperative findings and postoperative knee range motion after cruciate-retaining total knee arthroplasty.

BACKGROUND: Total knee arthroplasty (TKA) alleviates pain and improves daily living activities in individuals with end-stage osteoarthritis of the knee. However, up to 20% of patients have sub-optimal outcomes after TKA. OBJECTIVE: No studies have clarified the intraoperative factors that affect postoperative range of motion (ROM) after cruciate-retaining (CR) TKA. Thus, this study aims to clarify these factors. METHODS: Patients with knee osteoarthritis with varus knee deformity who underwent CR-TKA between May 2019 and December 2020 were included in this study. One year after surgery, patients were stratified into two groups based on knee flexion: Group F (over 120∘) and Group NF (below 120∘). Patient backgrounds including age, body mass index, hip knee angle, preoperative range of motion for both extension and flexion, intraoperative center joint-gap measurements of 0∘, 30∘, 45∘, 60∘, 90∘, and 120∘ of knee flexion using a tensor, intraoperative anterior-posterior (AP) laxity measurements of 30∘ and 90∘ of knee flexion using an instrumental laximeter were compared between the groups. Univariate analyses between the groups were used to construct the initial model. The receiver operating characteristic curve was also analyzed. The predictive variables included in the final model were selected by stepwise backward elimination. RESULTS: Intraoperative AP laxity with 30∘ of knee flexion smaller than 10.8 mm was a significant positive prognostic factor (OR: 1.39, 95% CI: 1.08-1.79, P= 0.011) of postoperative ROM over 120∘ of knee flexion one year after surgery. The sensitivity, specificity, PPV, and NPV were 70.9%, 82.4%, 92.9%, and 46.7%, respectively. CONCLUSION: Intraoperative AP laxity smaller than 10.8 mm was a significant positive predictive factor for obtaining knee flexion greater than 120∘ one year after surgery when using CR-TKA and its PPV was high up to 92.9%.

Increased Bone Plug Depth From the Joint Increases Tunnel Enlargement in Anterior Cruciate Ligament Reconstruction Using Bone-Patellar Tendon-Bone Autograft With Suspensory Femoral Fixation.

Purpose: To determine a safe bone plug depth fixation zone based on early tunnel enlargement rates in anterior cruciate ligament (ACL) reconstruction using bone-patellar tendon-bone (BPTB) autograft with suspensory femoral fixation. Methods: Patients who had undergone rectangular tunnel ACL reconstruction using BPTB autograft with suspensory femoral fixation were retrospectively identified. Femoral and tibial tunnel aperture areas were measured on computed tomography 2 weeks and 6 months after surgery to calculate rates of femoral and tibial tunnel enlargement (FTE and TTE), respectively. Femoral bone plug depth (FBPD) and tibial bone plug depth (TBPD) were defined as the distance of the tip of the plug from the respective joint lines. Optimal FBPD and TBPD cutoff values were calculated for the following rates of FTE and TTE, respectively: 0%, 15%, 30%, and 50%. Results: Sixty-four patients (19 females, 45 males; mean age, 29.5 ± 12.3 years) were included in the study. The femoral and tibial tunnel apertures significantly enlarged over time. FBPD (P < .001; r = 0.607) and TBPD (P = .013; r = 0.308) were positively correlated with FTE and TTE, respectively. The optimal FBPD cutoff value was 2.8 mm for FTE rates of 0% and 15%, 3.6 mm for 30%, and 6.0 mm for 50%. The optimal TBPD cutoff value was 1.48 mm for a 0% TTE rate and 5.1 mm for those higher. The cutoff value specificities were lower for the tibial tunnel than the femoral tunnel for each tunnel enlargement rate. Conclusion: Early tunnel enlargement and bone plug depth were significantly correlated in bone the femoral and tibial tunnels. The degree of correlation was higher in the femoral tunnel. To minimize bone tunnel enlargement, the distal end of the femoral bone plug should be placed less than 2.8 mm from the tunnel aperture. Level of Evidence: Level IV, therapeutic case series.

Prevention of Postoperative Cognitive Dysfunction by Minocycline in Elderly Patients after Total Knee Arthroplasty: A Randomized, Double-blind, Placebo-controlled Clinical Trial.

BACKGROUND: There are no effective pharmacologic interventions for preventing postoperative cognitive dysfunction in daily practice. Since the antibiotic minocycline is known to suppress postoperative neuroinflammation, this study hypothesized and investigated whether minocycline might have a preventive effect on postoperative cognitive dysfunction after noncardiac surgery. METHODS: This study included patients aged more than 60 yr undergoing total knee arthroplasty under general anesthesia. They were randomly assigned to minocycline and placebo groups, to orally receive 100 mg of minocycline or placebo twice daily from the day before surgery until the seventh day after surgery. Cognitive function was evaluated before surgery, and 1 week and 3 months after surgery, using a battery of four cognitive function tests, including Visual Verbal Learning Test, Trail Making Test, Stroop Color and Word Test, and Letter-Digit Coding Task. Additionally, 30 healthy volunteers were subjected to the same tests as the patients to examine the learning effect of repeated tests. The occurrence of postoperative cognitive dysfunction was judged from the results of the neurocognitive test battery, with consideration of the learning effect. The secondary endpoints were the effects of minocycline on postoperative delirium and postoperative pain. RESULTS: A total of 100 patients were randomized to the minocycline group, and 102 were randomized to the placebo group. The average age of patients was 75 yr. Evaluation showed no significant difference in the incidence of postoperative cognitive dysfunction between the minocycline and placebo groups at both 1 week (8 of 90 [8.9%] vs. 4 of 95 [4.2%]; odds ratio, 2.22 [95% CI, 0.64 to 7.65]; P = 0.240) and 3 months (15.3 of 90 [17.0%] vs. 15.3 of 95 [16.1%]; odds ratio, 1.07 [95% CI, 0.49 to 2.32]; P = 0.889) postoperatively. Missing data 3 months after surgery were corrected by the multiple imputation method. There were no differences between the two groups in postoperative delirium and postoperative pain. CONCLUSIONS: Minocycline is likely to have no preventive effect on postoperative cognitive dysfunction.

Large Reduction in Postoperative Posterior Tibial Slope Risks Anterior Collapse of the Tibial Component in Fixed-Bearing Unicompartmental Knee Arthroplasty.

Background: Although the posterior tibial slope (PTS) of the tibial component in unicompartmental knee arthroplasty is recommended to be between 3° and 7°, variations in preoperative PTS are wide. The purpose of this study was to evaluate the influence of the changes in preoperative and postoperative PTS on clinical outcomes. Methods: One-hundred and eighty-two knees that underwent medial fixed-bearing unicompartmental knee arthroplasty were evaluated retrospectively. The mean follow-up period was 36.4 ± 13.2 months (range, 24 to 63 months). Preoperative and postoperative PTS were measured on lateral radiographs. Knees were classified in the large reduction group if the postoperative PTS was reduced by more than 5° compared with the preoperative value and in the small reduction group if not. Knee flexion angle and 2011 Knee Society Knee Scoring System were evaluated at the last follow-up of at least 2 years. Results: Thirty-three knees were classified in the large reduction group, and 149 knees were classified in the small reduction group. The preoperative and postoperative PTS of large and small reduction groups were 10.9 ± 2.2, 3.6 ± 2.4 degrees and 7.7 ± 2.7, 7.1 ± 2.4 degrees, respectively. Flexion angle and 2011 Knee Society Knee Scoring System were not significantly different between the groups. However, the incidence of anterior collapse of the tibial component in the large group was significantly higher than that in the other group (P < .001). Conclusions: Large reduction in the postoperative PTS may be associated with anterior tibial collapse, and therefore this study shows one potential benefit for matching native slope.

The comparison of dexamethasone and triamcinolone periarticular administration in total knee arthroplasty: retrospective cohort study.

BACKGROUND: Intraoperative periarticular injection of corticosteroid effectively reduces perioperative pain in total knee arthroplasty (TKA). However, which corticosteroid is most effective for intraoperative periarticular injection remains controversial. We compared the effects of corticosteroids between dexamethasone and triamcinolone acetonide periarticular administration for reducing pain and postoperative nausea and increasing fasting blood glucose concentrations during the perioperative period following TKA. METHODS: One hundred and two patients who underwent TKA from August 2018 to September 2020 were divided into two groups: one received 10 mg dexamethasone for intraoperative periarticular injection and another receiving 40 mg triamcinolone acetonide. Postoperative pain scores at rest and during walking and nausea scores were recorded using a 0-to-10 Numerical Rating Scale. C-reactive protein (CRP) and fasting blood glucose levels were measured pre- and postoperatively. RESULTS: Pain scores in the triamcinolone group were significantly lower than in the dexamethasone group at rest 7 days postoperatively (1.5 vs. 2.0; p = 0.046) and while walking at both 72 h (3.9 vs. 4.8; p = 0.008) and 7 days postoperatively (3.2 vs. 4.0; p = 0.03). The CRP levels in the triamcinolone group were significantly lower than in the dexamethasone group at 7 days postoperatively (1.6 mg/dl vs. 3.0 mg/dl: p < 0.001). The fasting blood glucose levels at 1 day postoperatively were increased in both groups but not significantly different between the groups. No significant differences in the nausea score were noted between the groups. CONCLUSIONS: Triamcinolone acetonide periarticular administration provided greater pain relief by reducing inflammation to a greater degree than dexamethasone.

Medial meniscus extrusion as a predictor for a poor prognosis in patients with spontaneous osteonecrosis of the knee.

BACKGROUND: Risk factors for the progression of spontaneous osteonecrosis of the knee (SONK) remain unclear. The purpose of this study was to investigate the association between magnetic resonance imaging (MRI) findings of the meniscus and the prognosis of SONK. METHODS: A total of 78 consecutive patients (female 85%; mean age 75.6 ± 7.2 years old) diagnosed with SONK were included. Of these, 30 patients did not receive surgery within 1 year from the onset of SONK (conservative group), while the remaining 48 patients underwent unicompartmental knee arthroplasty due to worsening of symptoms (UKA group). Using MRI findings obtained within 3 months of the onset, we compared the types of meniscus tear and medial meniscus extrusion between the conservative group and UKA group. We performed a receiver operating characteristics (ROC) analysis to estimate the cut-off value. RESULTS: Patients in the UKA group showed greater medial meniscus extrusion (absolute value, 4.2 mm ± 1.9 vs. 2.8 mm ± 1.2, P = 0.001; relative percentage of extrusion (RPE), 45.7% ± 21.5 vs. 30.7% ± 12.9, P = 0.001) and a higher prevalence of radial tear (P = 0.021) than those in the conservative group. In the multivariate analysis, RPE remained a relevant independent factor (P = 0.035) for future UKA. An ROC analysis found that the cut-off point of RPE was 33% (sensitivity, 81.2%; specificity, 63.3%). CONCLUSION: RPE was a predictor of the prognosis of patients who underwent UKA within 1 year after the onset of SONK. Our results suggest that patients with RPE ≥ 33% are at high risk for progression.

Sagittal Inclination Angle of Graft Is Associated With Knee Stability After Anatomic Anterior Cruciate Ligament Reconstruction.

PURPOSE: To evaluate whether the sagittal inclination angle (SIA) of a graft is associated with postoperative knee stability after anatomic anterior cruciate ligament (ACL) reconstruction. METHODS: All patients who had undergone anatomic ACL reconstruction between April 2014 and September 2015 in addition to volunteers with no history of knee injury were eligible for inclusion in this study. The patients were evaluated by magnetic resonance imaging of the knee in full extension at 1 year after surgery, as were volunteers. The posterior tibial slope (PTS) angle and the SIA of the intact ACL and reconstructed graft were measured relative to each medial and lateral tibial plateau. The patients were examined for knee stability by the side-to-side difference in the anterior tibial translation on stress radiographs at minimum 2-year follow-up. RESULTS: We included 43 patients (26 male, 17 female, mean age 32.8 ± 14.8 years) and 12 volunteers (7 male, 5 female, mean age 28.7 ± 3.1 years) as normal controls. The mean follow-up duration was 29.8 ± 3.6 months. The mean PTS angle and mean SIA in the patients did not significantly differ from those of the intact ACL. The PTS angle in the patients was not significantly correlated with postoperative side-to-side difference in the anterior tibial translation. However, the graft SIA was significantly correlated with the postoperative anterior tibial translation (medial SIA; r = 0.42, P = .005, lateral SIA; r = 0.52, P < .001). CONCLUSIONS: Even if anatomically reconstructed, the graft SIA in reference to the tibial plateau at full knee extension is variable and is associated with postoperative knee stability. The larger graft SIA was correlated with graft laxity after anatomic ACL reconstruction. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Comparison of Intravenous and Periarticular Administration of Corticosteroids in Total Knee Arthroplasty: A Prospective, Randomized Controlled Study.

BACKGROUND: Corticosteroids are widely used in total knee arthroplasty (TKA) to relieve postoperative pain and prevent postoperative nausea. The aim of this prospective, randomized controlled study was to compare the effects of intravenous and periarticular administration of corticosteroids on pain control, prevention of postoperative nausea, and inflammation and thromboembolism markers following TKA. METHODS: One hundred patients undergoing TKA were randomly allocated to either the intravenous administration or periarticular injection group. The intravenous administration group received 10 mg dexamethasone 1 hour before and 24 hours after the surgical procedure, as well as a periarticular injection placebo during the procedure. The periarticular injection group received a 40-mg injection of triamcinolone acetonide during the surgical procedure, as well as an intravenous administration placebo 1 hour before and 24 hours after the procedure. Postoperative pain scores at rest and during walking and nausea scores were recorded according to the 0-to-10 Numerical Rating Scale. Interleukin-6 (IL-6), C-reactive protein (CRP), and prothrombin fragment 1.2 (PF1.2) were measured preoperatively and postoperatively. RESULTS: Pain scores at rest and during walking 24 hours postoperatively were significantly lower in the periarticular injection group than in the intravenous administration group. Nausea scores showed no significant difference between groups. IL-6 at 24 and 48 hours postoperatively also showed no significant difference between groups. CRP at 24 and 48 hours postoperatively was significantly lower in the intravenous administration group than in the periarticular injection group. In contrast, CRP at 1 week postoperatively was significantly higher in the intravenous administration group than in the periarticular injection group. The mean PF1.2 was significantly lower in the intravenous administration group than in the periarticular injection group at 4 hours postoperatively. Two cases of deep venous thrombosis in each group were detected with use of ultrasonographic examination. CONCLUSIONS: Periarticular injection of corticosteroids showed a better pain-control effect at 24 hours postoperatively than did intravenous administration, whereas the antiemetic effect was similar between treatments. Although intravenous administration had a better anti-thromboembolic effect than periarticular injection, the incidence of deep venous thrombosis was low in both groups. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Medial Meniscal Ramp Lesion Repair Concomitant With Anterior Cruciate Ligament Reconstruction Did Not Contribute to Better Anterior Knee Stability and Structural Properties After Cyclic Loading: A Porcine Model.

PURPOSE: To investigate the biomechanical efficacy of medial meniscal ramp lesion (MMRL) repair in anterior cruciate ligament (ACL) reconstruction regarding the graft protection effect after cyclic loading. METHODS: Specimens were randomized into 2 groups: (1) ACL reconstruction with unaddressed MMRL (Group U; n = 10), and (2) ACL reconstruction with repaired MMRL (Group R; n = 12). The specimens were tested cyclically (2,000 cycles, 0-40 N, 100 mm/min) in the direction of the native ACL and loaded to failure (100 mm/min) on a tensile tester. Statistically significant differences between the structural properties (length changes and anterior translations at the 100th, 500th, 1,000th, 1,500th, and 2,000th cycles, upper yield load, maximum load, linear stiffness, and elongation at failure) under cyclic loading and single-cycle loading were analyzed. RESULTS: There were no significant differences in length changes and anterior translations at the 100th, 500th, 1,000th, 1,500th, and 2,000th cycles. There were no significant differences in upper yield load (82.4 ± 31.2 N in Group U, 90.0 ± 38.5 N in Group R, P = .62), maximum load (109.9 ± 28.6 N in Group U, 124.0 ± 56.4 N in Group R, P = .48), linear stiffness (12.1 ± 4.7N/mm in Group U, 12.5 ± 4.3 N/mm in Group R, P = .84), or elongation at failure (13.5 ± 7.3 mm in Group U, 16.6 ± 7.5 mm in Group R, P = .30). CONCLUSIONS: Simultaneous MMRL repair at the time of ACL reconstruction did not decrease length changes and anterior translations during cyclic loading. In addition, simultaneous MMRL repair at the time of ACL reconstruction did not contribute to better postoperative structural properties. CLINICAL RELEVANCE: Simultaneous MMRL repair at the time of ACL reconstruction does not show a graft protective effect after cyclic loading. Graft elongation may occur during early rehabilitation.

Healing Status of Meniscal Ramp Lesion Affects Anterior Knee Stability After ACL Reconstruction.

BACKGROUND: Although the biomechanical importance of the ramp lesion in the anterior cruciate ligament (ACL)-deficient knee has been demonstrated, there is no clear consensus on the appropriate treatment for ramp lesions during ACL reconstruction. PURPOSE: To compare the postoperative outcomes for ramp lesions between patients treated with all-inside repair through the posteromedial portal and those whose ramp lesions were left in situ without repair during ACL reconstruction. We also determined whether ramp lesion healing status affected postoperative knee stability. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A total of 57 patients who underwent anatomic double-bundle ACL reconstruction between August 2011 and December 2017 had attendant ramp lesions. Of these, 25 ramp lesions that were considered stable were left in situ without repair (Nonrepaired group), and 25 ramp lesions, including 21 stable and 4 unstable lesions, were treated using all-inside repair through the posteromedial portal (Repaired group). We evaluated the side-to-side difference (SSD) in anterior tibial translation on stress radiographs and rotational stability by using the pivot-shift test 2 years after surgery, and healing status of the ramp lesions was evaluated on 3.0-T magnetic resonance imaging (MRI) scans 1 year after surgery. RESULTS: The mean SSDs in anterior translation were 2.4 ± 1.6 mm for the Nonrepaired group and 1.9 ± 1.6 mm for the Repaired group, with no significant differences. The positive ratios on the pivot-shift test were not significantly different between groups. Healing rates of ramp lesions on MRI scans showed a significant difference between the Nonrepaired group (60%) and the Repaired group (100%) (P = .001). The mean SSDs for knees in which the ramp lesion had healed as shown on MRI scans and those in which it had not healed were 1.9 ± 1.6 mm and 3.2 ± 1.1 mm, respectively, which was a significant difference (P = .02). CONCLUSION: Healing rates of ramp lesions were significantly better in the Repaired group than in the Nonrepaired group, although postoperative knee stability was not significantly different between groups. Anterior laxity in the knees in which the ramp lesion was unhealed was significantly greater compared with the knees in which the ramp lesion healed. All-inside repair through the posteromedial portal was a reliable surgical procedure to heal ramp lesions.

Preoperative hand-grip strength can be a predictor of stair ascent and descent ability after total knee arthroplasty in female patients.

BACKGROUND: Hand-grip strength was reported to be important predictor of functional limitation and disability related to low muscle strength in old people. The purpose of this study was to determine whether preoperative hand-grip strength predicts stair ascent and descent ability after total knee arthroplasty (TKA). METHODS: A total of 83 female patients (mean age 75.6 ± 7.2 years) who underwent unilateral TKA were included in this study. We measured body mass index, range of motion of both knees, bilateral quadriceps strength and hand-grip strength before and one year after TKA. One year after TKA, we had the subjects ascend and descend some stairs and recorded the gait pattern (step-to-step or step-over-step) and pain in both knees using a numerical rating scale. We divided the subjects into two groups according to gait pattern. These factors were compared between groups. Receiver Operating Characteristics (ROC) analysis was performed to estimate the preoperative hand-grip strength cut off point for the stair gait pattern. RESULTS: Pre- and postoperative mean hand-grip strengths were 20.1 ± 5.0 kg and 20.7 ± 5.4 kg, respectively, and there was a strong positive correlation between them (r = 0.82, P < 0.001). Quadriceps strength of both limbs significantly improved after TKA (P < 0.001). After TKA, all patients were able to perform both stair ascent and descent. The gait patterns of 27 patients were step-to-step, and 56 patients were step-over-step. Preoperative and postoperative quadriceps strength of both limbs and preoperative and postoperative hand-grip strength were significantly different between the groups. According to the ROC curve, the optimal cut off values of preoperative hand-grip strength for which female patients could ascend and descend the stairs by step-over-step after TKA was set at 19 kg. CONCLUSION: Preoperative hand-grip strength can be used in preoperative screening for stair ascent and descent ability after TKA.

Younger patients with high varus malalignment of the contralateral knee may be candidates for simultaneous bilateral total knee arthroplasty.

PURPOSE: Bilateral total knee arthroplasty (TKA) is being performed more frequently. However, a consensus on whether simultaneous or staged procedures should be performed is not available. This study reviewed the clinical course of contralateral knees in patients who underwent unilateral TKA (UTKA) to determine which patients are candidates for simultaneous bilateral TKA (BTKA). METHODS: One hundred eighty-six patients with osteoarthritis who underwent UTKA at a single hospital between 2006 and 2009 (follow-up mean, 10.1 years) were retrospectively investigated. Age, sex, obesity, contralateral knee pain, Hospital for Special Surgery score, femorotibial angle (FTA), and Kellgren-Lawrence grades at the time of initial surgery were used to evaluate the risk for requiring contralateral TKA. Survival analysis and receiver-operating characteristic (ROC) analysis were performed. RESULTS: Ninety-one patients (48.9%) underwent contralateral TKA. The FTA of the contralateral knee (CFTA) was an independent related factor (hazard ratio, 1.15; p < 0.001), and the CFTA cut-off value for the next surgery was 183° (area under the curve, 0.85; sensitivity, 80.7%; specificity, 76.2%). The 10-year Kaplan-Meier survival rates for the CFTA < 183° group and the CFTA ≥ 183° group were 79.1% and 27.0%, respectively. In the CFTA ≥ 183° group, age was the predictor of future TKA, and elderly patients tended to not require a second procedure. The age cut-off value for the next surgery was 76 years. CONCLUSIONS: Varus deformities in the contralateral knee predicted additional contralateral TKA. Patients with CFTA ≥ 183° and aged 75 years or younger are considered reasonable candidates for simultaneous BTKA. LEVEL OF EVIDENCE: III.

Magnetic Resonance Imaging Diagnosis of Medial Meniscal Ramp Lesions in Patients With Anterior Cruciate Ligament Injuries.

PURPOSE: To prospectively evaluate the sensitivity and specificity of magnetic resonance imaging (MRI) for diagnosing ramp lesions, to compare them between 1.5- and 3-T MRI, and to evaluate whether bone contusion of the posterior lip of the medial tibial plateau was associated with ramp lesions. METHODS: For 155 knees that underwent primary ACL reconstruction, we prospectively examined for ramp lesions and medial meniscal body tears on MRI. MRI diagnosis of ramp lesions required high signal irregularity of the capsular margin or separation in the meniscocapsular junction of the medial meniscus posterior horn on sagittal images. Bone contusion of the posterior lip of the medial tibial plateau was verified in 105 knees with MRI performed within 6 weeks after injury. All ramp lesions were identified by transcondylar observation during surgery. The sensitivity and specificity of MRI for ramp lesions and body tears were measured. Furthermore, we evaluated whether bone contusion of the medial tibial plateau was associated with ramp lesions. The χ-square test was used for statistical analysis. RESULTS: During surgery, ramp lesions were observed in 46 knees and medial meniscal body tears were seen in 35 knees. The sensitivity of MRI for ramp lesions was 71.7% and specificity was 90.5%. The sensitivity for ramp lesions was significantly lower than that for meniscal body tears (94.3%) (P = .01). The sensitivity of 3-T MRI (83.3%) was superior to that of 1.5-T MRI (67.6%), but not significantly different. The incidence of bone contusions was not significantly different among ramp lesions (38.5%), body tears (40.0%), or no tears (30.5%). CONCLUSIONS: The sensitivity of MRI for diagnosing ramp lesions was significantly lower than that for medial meniscal body tears. Bone contusion of the posterior lip of the medial tibial plateau on MRI was not associated with ramp lesions. LEVEL OF EVIDENCE: Level III, comparative trial.

Factors Associated With Posterior Cruciate Ligament Tightness During Cruciate-Retaining Total Knee Arthroplasty.

BACKGROUND: The purpose of our study was to identify factors affecting posterior cruciate ligament (PCL) tightness during cruciate-retaining total knee arthroplasty. METHODS: A total of 225 varus osteoarthritic knees that underwent cruciate-retaining total knee arthroplasty were included in this study. When the flexion gap was tighter than the extension gap after all bone resection and the lift-off sign was positive during surgery, the PCL was released. The association between PCL release and potential risk factors, such as age, gender, body mass index, preoperative range of motion, anterior cruciate ligament status, preoperative hip-knee-ankle angle (HKA), decrease in posterior condylar offset, and also change in tibial posterior slope angle (TPSA) from preoperative to postoperative measurement, was evaluated by univariate and multivariate logistic regression analyses. RESULTS: The PCL was released in 68 of 225 knees (30.2%). According to the univariate logistic regression analysis, preoperative knee flexion angle (odds ratio [OR], 0.98), anterior cruciate ligament status (OR, 3.94), the decrease in medial (OR, 0.73) and lateral posterior condylar offset (OR, 0.76), preoperative HKA (OR, 1.1), preoperative (OR, 1.15) and postoperative TPSA (OR, 0.77), and the decrease in TPSA (OR, 1.23) were associated with PCL release. Multivariable stepwise logistic regression analysis demonstrated that preoperative HKA (P < .001), postoperative TPSA (P = .02), and the decrease in TPSA (P < .001) were independently associated with PCL release. CONCLUSION: Many factors are associated with PCL tightness. The change in TPSA between preoperative and postoperative measurements was a higher risk factor than postoperative TPSA.

Does Residual Varus Alignment Cause Increasing Varus Laxity at a Minimum of Five Years After Total Knee Arthroplasty?

BACKGROUND: The purpose of this study is to investigate whether varus-valgus laxity of cruciate-retaining (CR) total knee arthroplasty (TKA) changes between 1 year and >5 years after surgery based on postoperative limb alignment. METHODS: One hundred twenty-one varus osteoarthritic knees that underwent CR TKA were included. The minimum follow-up was 5 years. Weight-bearing full-leg radiographs were obtained postoperatively and the hip-knee-ankle (HKA) angle was measured. Knees were grouped in varus (HKA angle ≤ -3°, 47 knees) and neutral groups (-3° < HKA angle < 3°, 70 knees). The range of motion was measured and a Hospital for Special Surgery score was obtained at the last follow-up. Varus-valgus laxity at 15° of knee flexion was measured with stress radiographs after 1 year and at the last follow-up. RESULTS: No knees required revision surgery. The mean knee flexion angle (121.0° vs 117.1°) and Hospital for Special Surgery score (90.3 vs 90.4) at the last follow-up were not significantly different between the varus and neutral groups. In both groups, there was no significant change in varus or valgus laxity between 1 year and at the last follow-up. CONCLUSION: Postoperative residual varus limb alignment did not lead to increasing varus laxity after CR TKA in the mid-term.

Efficacy of ß-Tricalcium Phosphate Graft into the Bone Defects after Bone-Patellar Tendon-Bone Anterior Cruciate Ligament Reconstruction.

This prospective pilot study investigated whether grafting ß-tricalcium phosphate (B-TCP) into the bone-patellar tendon-bone (BPTB)-harvesting site after anterior cruciate ligament reconstruction would accelerate bone and tendon regeneration in the grafted site. Overall, 19 patients agreed prospectively to undergo regular morphological and histological examinations of the B-TCP-grafted site. Postoperative radiographic, ultrasonographic, and magnetic resonance imaging (MRI) examinations were performed to evaluate the grafted site at 1, 3, 6, and 12 months. Postoperative knee function and donor-site morbidity were assessed at 12 months using the kneeling test. A histological examination was also performed at this time Radiographic examination and MRI showed that the grafted B-TCP was completely absorbed and remodeled into normal bone structure in the tibia and patella at 6 months postoperatively. Histological and ultrasonographic examinations of all subjects showed that the grafted B-TCP was substituted by normal bone tissue, and the patellar tendon - bone junction had regenerated at 12 months postoperatively. Clinical functional knee tests showed good recovery of the donor site. All patients could perform kneeling and knee walking on hard ground. The results of this pilot study suggest that grafting B-TCP into the BPTB-harvesting site promotes the remodeling process of the bone and patellar tendon structures. This surgical treatment would decrease an incidence of the anterior knee pain after ACLR using a BPTB autograft.

Tibial Tubercle in Valgus Osteoarthritic Knees Is More Laterally Positioned Than in Varus Knees.

BACKGROUND: The tibial tubercle (TT) is the most reliable landmark of the tibial component rotation in total knee arthroplasty. However, there is no report comparing the position of the TT between valgus and varus osteoarthritic knees. METHODS: Using preoperative computed tomography, we measured the TT-posterior cruciate ligament (PCL) distance representing the degree of lateralization of the TT and the angle between Akagi's anteroposterior (AP) axis and the dorsal condylar line (DCL) of the tibia in 36 valgus and 40 varus osteoarthritic knees and compared them. RESULTS: The mean TT-PCL distances in valgus and varus knees were 26.1 (18.2-36.8) and 17.2 mm (10.3-22.6), respectively, with a significant difference (P < .001). Twenty-four of 36 valgus knees (67%) had abnormal TT-PCL (>24 mm). The mean AP-DCL angles in valgus and varus knees were 103° (95.8°-114.8°) and 93.2° (85.3°-99.6°), respectively, with a significant difference (P < .001). CONCLUSION: The TT in valgus knees was significantly more laterally positioned than in varus knees. Also, Akagi's AP axis in valgus knees was significantly more externally rotated relative to the DCL of the tibia than in varus knees. Attention is necessary to correct rotational alignment without posterolateral overhang of the tibial component during total knee arthroplasty, particularly for valgus knees.