Previous Meniscectomy Research Articles

Poster 285: Two-Year KOOS Improvement after Unloading Treatment With Implantable Shock Absorber in Post-Meniscectomy Patients

Objectives: Meniscectomy is a common orthopaedic procedure designed to improve symptoms. However, partial or full meniscectomy can reduce the structure’s ability to absorb and distribute normal joint load, which can result in post-meniscectomy pain. Subjects with and without previous meniscectomy and knee OA were treated with an implantable shock absorber (ISA) to unload the medial compartment. The purpose of this study was to compare subjects with and without previous meniscectomy who were treated with the ISA to evaluate if prior meniscectomy impacted outcomes scores. The objective was to determine if prior meniscectomy impacted two-year KOOS outcomes for patients treated with an implantable shock absorber. Methods: Eighty-one (81) subjects had the ISA implanted, and 23 subjects (28%) previously underwent partial (22) or full (1) medial meniscectomy. Subjects in the medial meniscectomy arm were 50.9 years old compared to 51.4 years old in the non-meniscectomy arm (p=0.8). The two arms were comparable for other baseline demographics, such as BMI, OA disease severity and duration of symptoms. Baseline and 2-year improvements in KOOS subscales were recorded. Results: Subjects with and without previous meniscectomy reported similar improvements in KOOS scores at two years. The post-meniscectomy group reported KOOS Pain improvement of 41.3 points from baseline, compared to a 47.3 point improvement in the non-meniscectomy group (p=0.2584) at two years. Similarly, the meniscectomy group reported a 43.6 improvement in KOOS ADL, compared to a 45.9 point improvement in the non-meniscectomy group (p=0.7075). Subjects reported similarly high levels of improvement in the post-meniscectomy arm compared to the non-meniscectomy group (38.2 vs. 51.4, p=0.1108) on the Sports/Rec Activities scale of KOOS. Through two years, none (0%) of the meniscectomy group underwent a conversion to arthroplasty, and study safety events were comparable between the two arms (p=0.2109). Conclusions: At two years, the implantable shock absorber provided dramatic improvement on KOOS subscales for subjects with prior meniscectomy and knee OA that is comparable to the improvement for subjects without history of meniscectomy. While this study population was more of a general OA population and not a sports-oriented population, the improvement in KOOS Sports/Rec was notable for the post-meniscectomy cohort. Given the attractive safety profile, the ISA is a potential treatment for patients with post-meniscectomy pain, and the treatment should be evaluated further in this population.

Predictors of Long-term Patient-Reported Outcome Measures After Collagen Meniscal Implant for Partial Meniscal Defects.

Collagen meniscal implant (CMI) is considered an effective procedure for reducing knee pain and improving knee function after previous meniscectomy. Nevertheless, the current knowledge regarding long-term patient reported-outcome measures after CMI is limited. To evaluate clinical outcomes, reoperations, and failures of CMI at a minimum 10-year follow-up. Case series; Level of evidence, 4. Consecutive patients who underwent CMI at a single institution were screened for eligibility. Inclusion criteria for the present study were (1) medial or lateral CMI; (2) isolated or combined procedure with anterior cruciate ligament reconstruction, knee osteotomy, or cartilage treatment; and (3) follow-up between 10 and 15 years. Demographics and surgical details were obtained via chart review. Patients were asked if they were satisfied with the procedure and were evaluated with the Lysholm score, Knee injury and Osteoarthritis Outcome Score (KOOS), visual analog scale for pain, and Tegner score at the final follow-up. Cases requiring partial or total scaffold removal for any reason (including scaffold breakage, infection, or surgery for osteoarthritis progression) were considered surgical failure. Survival analysis was performed with Kaplan-Meier curve, and clinical scores were analyzed based on the Patient Acceptable Symptom State (PASS). A total of 92 patients (mean age, 42.2 years were included in the analysis. A significant improvement in all clinical scores was reported between the preoperative evaluation and the last follow-up. A chondropathy with Outerbridge grade ≥3 was associated with significantly overall lower clinical scores, while a timing from meniscectomy to CMI of ≥5 years determined more pain at rest and reduced Quality of Life in the KOOS subscale. No significant difference was found in terms of clinical scores between patients undergoing isolated and combined procedures. At the final follow-up, the mean Lysholm score was 76.3 points. In total, 12 cases (13%) were considered surgical failures. Sixteen patients (17%) did not reach PASS for the Lysholm score, with a total of 28 cases (30%) classified as clinical failures. Overall, 19% (KOOS Pain) and 40% (KOOS Symptoms) of patients did not achieve the PASS in the KOOS subscales. Chondropathy with Outerbridge grade ≥3 was associated with a higher risk of not achieving the PASS in all the KOOS subscales, while age at surgery of ≥45 years resulted in a lower risk of not achieving PASS in the Pain subscale. At the last follow-up, 63% of patients were still involved in sports activity, with 41% at the same or higher level. Finally, 80% of the patients were satisfied with the procedure. Up to 10 years after surgery, around 70% of the patients who underwent CMI reported satisfactory clinical results, with clinical subjective scores still higher compared with the preoperative evaluation. Overall, 30% of cases were considered clinical failures, with 13% considered surgical failures and 17% not meeting the PASS for the Lysholm score. In addition, cartilage status and time from meniscectomy were shown to have a negative impact on the outcomes, while an age ≥45 years was associated with less pain. There was no clinical difference between patients who underwent isolated CMI or combined procedures.

Influence of Previous Arthroscopic Meniscectomy on Midterm to Long-term Outcomes After Medial Open-Wedge High Tibial Osteotomy

Background: Few studies have evaluated the clinical and radiological outcomes of medial open-wedge high tibial osteotomy (MOWHTO) in patients who had previously undergone arthroscopic meniscectomy. Purpose: To verify whether previous arthroscopic meniscectomy affects the clinical and radiological outcomes of MOWHTO. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 183 consecutive knees that underwent MOWHTO and had a minimum 5 years of follow-up were retrospectively reviewed. We compared the preoperative and postoperative clinical and radiological data of 32 knees with a history of meniscectomy (previous meniscectomy group) to 151 control knees without a history of meniscectomy. Cartilage status was also compared at first- and second-look arthroscopic surgery according to the International Cartilage Repair Society grading system. Failure was defined as conversion to total knee arthroplasty or revision MOWHTO. On subgroup analysis, the previous meniscectomy group was divided into 2 subgroups based on the time from meniscectomy to MOWHTO (<3 vs ≥3 years). Results: The mean age at the time of surgery was 55.9 years (range, 38-70 years), and the mean follow-up period was 86.2 months (range, 60-164 months). The mean time between meniscectomy and MOWHTO was 48.9 months (range, 5-156 months), and all meniscectomy procedures were performed on the medial side. Preoperative patient characteristics were similar between the study groups. Clinical and radiological outcomes were not significantly different between the groups at the latest follow-up, and no significant between-group differences were observed regarding postoperative cartilage status on arthroscopic examination. One knee in the control group underwent conversion to total knee arthroplasty at 7 years postoperatively for arthritic progression. Subgroup analysis of the previous meniscectomy group indicated no significant differences in clinical outcomes based on the time from meniscectomy to MOWHTO. Conclusion: Based on the results, a history of meniscectomy did not adversely affect the midterm to long-term outcomes of MOWHTO. Furthermore, the time between previous meniscectomy and MOWHTO was not associated with the clinical outcomes of MOWHTO.

Isolated meniscus allograft transplantation with soft-tissue technique effectively reduces knee laxity in the presence of previous meniscectomy: In-vivo navigation of 18 consecutive cases

ObjectivesAlthough meniscal allograft transplantation (MAT) is a well-established procedure with satisfactory clinical results, limited in vivo kinematic information exists on the effect of medial and lateral MAT performed in the clinical setting. The purpose of the present study was to evaluate the biomechanical effect of arthroscopic isolated medial and lateral MAT with a soft-tissue fixation on pre- and post-operative knee laxity using a surgical navigation system. Methods18 consecutive patients undergoing MAT (8 medial, 10 lateral) were enrolled. A surgical navigation system was used to quantify the anterior-posterior displacement at 30 and 90 degrees of knee flexion (AP30 and AP90), the varus-valgus rotation at 0 and 30 degrees of knee flexion (VV0 and VV30) and the dynamic laxity on the pivot-shift test (PS), which was determined through the anterior displacement of the lateral tibial compartment (APlat) and posterior acceleration of the lateral tibial compartment during tibial reduction (ACC). Data from laxity before and after MAT were compared through paired t-test (p ​< ​0.05). ResultsAfter medial MAT, there was a significant decrease in tibial translation of 3.1 ​mm (31%; p ​= ​0.001) for AP30 and 2.3 ​mm (27%; p ​= ​0.020) for AP90, a significant difference of 2.5° (50%; p ​= ​0.002) for VV0 and 1.7° (27%; p ​= ​0.012) for VV30. However, medial MAT did not determine any reduction in the PS kinematic data. Lateral MAT determined a significant decrease in the tibial translation of 2.5 ​mm (38%; p ​< ​0.001) for AP30 and 1.9 ​mm (34%; p ​= ​0.004) for AP90 as well as a significant difference of 3.4° (59%; p ​< ​0.001) for VV0 and of 1.7° (23%; p ​= ​0.011) for VV30. There was also a significant reduction of the PS of 4.4 ​mm (22%; p ​= ​0.028) for APlat and 384.8 ​mm/s2 (51%; p ​= ​0.005) for ACC. ConclusionMAT with soft-tissue fixation results in a significant laxity reduction in an in-vivo setting. Medial MAT improved knee kinematics by determining a significant reduction with particular emphasis on AP translation and VV manoeuvre. Conversely, Lateral MAT determined a massive reduction of the PS and a mild decrease of the AP translation and VV manoeuvre. Study designControlled laboratory study.

Poster 242: Predictors of the Ten-Year Patient-Reported Outcome Measures After Collagen Meniscus Implant (CMI) for Partial Meniscus Deficiency

Objectives: Collagen Meniscus Implant (CMI) is considered an effective procedure for reducing knee pain and improving knee function after previous meniscectomy. Nevertheless, the current knowledge regarding the clinical results of CMI are limited to small case series at short- to mid-term follow-up studies. The goal of the present study was to evaluate clinical outcomes, reoperations, and failures of CMI at a minimum 10 years of follow-up. Methods: Consecutive patients who underwernt CMI at a single institution were screened for elegibility. Inclusion criteria for the present study were (1) Medial or Lateral CMI, (2) Isolated or combined procedure with ACL reconstruction, knee osteotomy or cartilage treatment, (3) follow-up between 10 and 15 years. Demographics and surgical details were obtained via chart review. Patients were asked if they were satisfied with the procedure and were evaluated with the Lysholm score, Knee injury and Osteoarthritis Outcome Score (KOOS), visual analog scale (VAS) for pain, and Tegner score at the final follow-up. Survival analysis was performed with Kaplan-Meier curve, and clinical scores were analyzed based on the Patient Acceptable Symptom State (PASS). Results: A total of 92 patients (mean age, 42.8 years) were included in the analysis. A significant improvement in all the clinical scores was reported between the preoperative evaluation and the last follow-up. A chondropaty with outerbridge grade ≥III was associated with significantly overall lower clinical score, while a timing from meniscectomy to CMI implant to ≥5 years determined more pain at rest and lower score in the KOOS quality of life. Overall, 25% of patients did not achieved the PASS for Lysholm score and a percentage variable from 19% (KOOS Pain) and 40% (KOOS Symptoms) did not achieved the PASS in the KOOS subscales. Chondropaty with outerbridge grade ≥III was associated with an higher Risk of not achieving the PASS in all the KOOS subscales, while an age at surgery ≥45 years was resulted in a lower risk of not achieving PASS in the pain subscale. At the last follow-up 63% of patients returned to sport practice after CMI implantation, with 41% at the same or higher level. Finally, 80% of the patients were satisfied with the procedure Conclusions: CMI provided satisfactory results in terms of function, symptoms, sports and quality of life in 60% to 80% of the patients after more than 10 years of follow-up with clinical scores still higher compared to the preoperative evaluation. The cartilage status and the time from meniscectomy have shown to impact negatively on the outcomes, while an age &gt;45 years was associated with less pain. [Table: see text][Table: see text]

Isolated Meniscus Allograft Transplantation Effectively Reduces Knee Laxity In the Presence of Previous Meniscectomy: In-Vivo Navigation of 18 Consecutive Cases

Isolated Meniscus Allograft Transplantation Effectively Reduces Knee Laxity In the Presence of Previous Meniscectomy: In-Vivo Navigation of 18 Consecutive Cases

Survivorship and Reoperation of 324 Consecutive Isolated or Combined Arthroscopic Meniscal Allograft Transplants Using Soft Tissue Fixation

Background: Meniscal allograft transplant (MAT) is an effective treatment for relieving symptoms and improving knee function in patients who experience symptomatic unicompartmental knee pain after a previous meniscectomy. However, the literature contains a paucity of studies assessing the survival rate and prognostic factors of soft tissue MAT. Purpose: To report the survivorship of a large, single-center cohort of consecutive patients treated with arthroscopic MAT using soft tissue technique and to investigate variables that could potentially influence failures and outcomes. Study design: Case series; Level of evidence, 4. Methods: Consecutive MAT procedures totaling 364 performed in a single institution between June 2004 and April 2019 were screened and assessed for eligibility. Subjective clinical scores (Lysholm score, Tegner activity scale, and visual analog score) were collected preoperatively and at 2, 5, 7, and 10 years of follow-up. Two survival analyses were performed using Kaplan-Meier curves, with surgical failure (defined as any graft revision) and clinical failure (defined as a Lysholm score <65 points) used as endpoints. Univariate analyses were performed using reoperations, surgical failure, clinical failure, and different demographic and surgical characteristics as endpoints. Results: A total of 324 consecutive patients were evaluated at a mean follow-up 5.7 ± 3.0 years. Of these, 189 (58%) underwent an associated surgical procedure. A total of 22 patients (6.8%) were considered to have experienced surgical failure, and no predictors of surgical failure were identified based on the relevant variables. When all patients were considered, a significant improvement in all of the patient-reported outcome measures was present between the preoperative assessment and the last follow-up (P < .001), with no significant decrease over time. Moreover, 70 (21.6%) patients were considered to have experienced clinical failure; the need for concurrent cartilage procedures (odds ratio, 0.16; P = .001) and anterior cruciate ligament (ACL) reconstruction (odds ratio, 0.40; P = .059) were predictors of failure. Finally, a lower survival rate was reported in female patients compared with male patients (49% vs 69%, respectively; P = .007) and in patients who required cartilage surgery (P = .014). In particular, patients who required cartilage surgery showed nearly half the survival rate compared with those with required no cartilage procedures at 10-year follow-up (36.4% vs 71%, respectively; P = .029). Conclusion: Female sex and the need to combine MAT with a cartilage procedure or ACL reconstruction could result in an increased rate of clinical failure at midterm follow-up.

Paper 30: Superior Improvements in Knee Pain and Function with a Novel Synthetic Medial Meniscus Replacement Prosthesis Compared to Non-surgical Care in Subjects with Knee Pain Following Partial Meniscectomy: Three-year Results from Two Prospective US Clinical Trials

Objectives:Results from 2 FDA-regulated clinical trials demonstrate superiority of a synthetic medial meniscus prosthesis to non-surgical care in treating persistent or recurrent knee pain following previous partial meniscectomy.Arthroscopic partial meniscectomy (APM) is the most common surgical treatment for symptomatic, irreparable meniscal tears that do not improve with non-surgical care. For many patients, APM is associated with improvements in knee pain and function, but a subset of patients report persistent or recurrent knee pain 1-2 years after APM surgery. Current treatment options for post-APM knee pain are limited, especially for patients considered too young for knee replacement. The polymeric medial meniscus prosthesis (NUsurfaceâ, Active Implants, Memphis TN) mimics the biomechanical function of the natural medial meniscus and provides relief from pain and improved function in subjects with knee pain following APM. The meniscus prosthesis met the primary endpoint of superiority over non-surgical care at 2 years. The current hypothesis was that investigational subjects maintained superior improvements in knee-related pain, function, and quality of life, compared to non-surgical subjects, through 3 years of follow-up.Methods:242 subjects (176 investigational, 66 control) treated in 2 prospective, concurrent clinical trials in the U.S., and pooled for analysis: a randomized controlled superiority trial (RCT) comparing the investigational device (investigational group) to non-surgical care (control), and a single-arm, prosthesis-only trial. Subjects had persistent knee pain and one or more previous partial meniscectomies at least 6 months before trial entry. Subject follow-up visits at 1.5 months, 6 months, 1, 2 and 3 year. Patient-reported knee pain, function, and quality of life were assessed using the Knee Injury and Osteoarthritis Outcome Score (KOOS). Treatment cessation was defined as any investigational subject who discontinued the per-protocol treatment by permanent prosthesis removal, or control subjects undergoing any surgical procedure on the index knee. Investigational subjects who underwent subsequent surgical procedures on index knees (e.g. prosthesis exchange) remained in the trial. The investigational and control cohorts analyzed were compared at each time point using a two tailed t-test. All baseline cohort comparisons of demographics were not statistically different (p>0.05).Results:The magnitude of improvement from baseline to 3 years was statistically superior in the investigational cohort, compared to the control cohort for all 6 KOOS subscales (Figure 1), including the primary outcomes of KOOS Overall and KOOS Pain (Figure 1A, B). Improvement in KOOS Overall and KOOS Pain for the investigational and control cohorts at 3 years were 26.4 vs 10.4 points, and 26.9 vs 15.4 points, respectively (Figure 1). These data show a statistically significant improvement, exceeding a clinically meaningful improvement of ≥20 points versus controls as early as 6 months (20.0 vs 9.2 pts), continuing through the 3-year timepoint. Controls experienced a 35% decline in KOOS Overall improvement between the 2-year and 3-year timepoint (15.9 vs 10.4). Accountability of patients not available or yet reaching the 3-year follow-up time period are reflected in Table 1. Treatment cessation through 3 years was 31% greater in the control cohort than the investigational cohort (15.0% vs. 19.6%).Conclusions:Three-year results demonstrate statistically superior relief from post-APM knee pain and function compared to non-surgical care alone. At 3 years, the magnitude of change from baseline to 3 years significantly favored the investigational device compared to control treatments. Investigational subjects discontinued treatment at a far lower rate compared to control subjects. Investigational subjects who underwent a device exchange or repositioning procedure were able to continue therapy benefit with the medial meniscus prosthesis. In all KOOS subscales, the investigational subjects experienced superior improvements and outcomes at 3 years compared to non-surgical care subjects.Figure 1.Magnitude of improvement in KOOS Overall (A), Pain (B), Symptoms (C), Activities of Daily Living (ADL; D), Sports and Recreation (E), and Quality of Life (QOL; F) from baseline (BL) to each follow-up time point.Table 1.Numbers are patients available to complete the KOOS questionnaire; Numbers in parentheses are percentages of the baseline population.

Cost-Effectiveness Analysis of a Medial Meniscus Replacement Prosthesis for the Treatment of Patients with Medial Compartment Pain in the United Kingdom.

BackgroundThe most common intra-articular knee injury is a meniscal tear, which commonly occurs secondary to trauma following twisting or hyperflexion. Treatment options for meniscal tears can either be surgical or non-surgical, and range from rest, exercise, bracing and physical therapy to surgical intervention, including meniscal repair and partial meniscectomy. In patients with persistent pain following loss of meniscus tissue, treatment can include partial replacement or meniscal allograft transplantation. The NUsurface® prosthesis has been developed as a treatment option for patients experiencing persistent knee pain post medial meniscus (MM) surgery.ObjectiveThe aim of this study was to assess the cost effectiveness of MM replacement using NUsurface for the treatment of patients with medial compartment pain following previous partial medial meniscectomy, from a UK health service perspective.MethodsAn economic decision-analytic model was developed to assess the cost per quality-adjusted life-year (QALY) gained associated with the introduction of MM replacement using NUsurface compared with non-surgical standard of care, over a lifetime time horizon. The model structure was primarily informed by a previous clinical trial (VENUS) and was developed based on the clinical pathways typically followed by patients with this condition, with treatment pathways and probabilities of clinical progression adjusted depending on whether patients were receiving the intervention or undergoing current practice. A hypothetical cohort of adult patients (mean age of 50 years) was modelled, with clinical data sourced from the VENUS study as well as relevant UK literature. Both deterministic and probabilistic sensitivity analyses were carried out to explore uncertainty in the model results.ResultsThe base-case probabilistic results indicate that MM replacement using NUsurface is likely to be cost effective across a range of willingness-to-pay (WTP) thresholds (95% probability of being cost effective at the National Institute for Health and Care Excellence (NICE)-recommended £20,000 WTP threshold). Although per-patient costs increase, QALYs are also gained, with the incremental cost per QALY (probabilistic value = £5011) being below £20,000. Deterministic sensitivity analyses indicate that the parameters that have the greatest impact on results are the failure rate in the control group (current practice), utility scores, and the cost of undergoing MM replacement using NUsurface.ConclusionsBased on the analysis presented, MM replacement with the NUsurface prosthetic implant is likely to be a cost-effective use of UK health care service resources compared with current standard care.Supplementary InformationThe online version contains supplementary material available at 10.1007/s41669-022-00336-4.

Lateral collagen meniscus implant (CMI): techniques and outcomes-a narrative review.

The menisci increase the stability of the tibio-femoral joint, distribute axial load, absorb shock, and provide nutrition and lubrification to the knee articular cartilage. Therefore, is it clear the importance of the meniscus on the overall knee function and the need to preserve it during arthroscopic surgery. However, according to many registry databases, meniscectomy is still the most performed meniscus surgery. In a percentage of patients, knee pain and swelling, as well as bone edema on the tibial plateau, could follow meniscus resection; this constellation of symptoms is known as "post-meniscectomy syndrome". If this syndrome is not promptly managed, a rapid worsening of the symptoms and develop of knee osteoarthritis could be expected. While dealing with such condition, the clinician must perform first an accurate clinical examination and a full radiological evaluation. If the patient is candidate for surgery, the replacement of the resected tissue should be performed: a meniscus allograft should be implanted in case of previous total meniscectomy or a meniscus scaffold if the patients has an history of a previous partial resection. The present article represents a comprehensive review of the literature and aims to discuss basic science, preoperative planning and evaluation, indication, surgical technique, and outcomes of the lateral collagen meniscus implant (CMI), a biologic scaffold aimed at replacing partial meniscal defects.

Meniscus Allograft Transplantation Obtained From Adult Patients Undergoing Total Knee Arthroplasty May be Used for Younger Patients After Lateral Discoid Meniscus Meniscectomy

PurposeTo investigate the clinical outcomes following meniscus allograft transplantation (MAT) to replace removed discoid lateral meniscus using intact lateral meniscus obtained from patients undergoing total knee arthroplasty for medial compartment osteoarthritis.MethodsPediatric patients who underwent MAT secondary to partial or total meniscectomy due to discoid lateral meniscus between August 2010 and November 2018 were identified. Lateral menisci with bone blocks were transplanted arthroscopically. The demographic data, range of motion, meniscal allograft failure, which was defined as removal of an implanted meniscus, and complications were recorded. The Lysholm score and the Kellgren-Lawrence (KL) grade on radiographs were evaluated preoperatively and at final follow-up. The Knee injury and Osteoarthritis Outcome Score was evaluated in the final follow-up.ResultsEight patients who were symptomatic after discoid lateral meniscectomy were included. Donated allografts were harvested from adult patients aged between 64 and 78 years (mean 70.5 years). The mean age at previous meniscectomy and MAT were 10.5 and 18.1 years, respectively. All patients were followed up for a mean time of 5.2 years, and there were no cases of meniscus failure and complication. The Lysholm score significantly improved from preoperative to the final follow-up. Preoperatively, 6 and 2 knees were of KL grades II and III, respectively. At final follow-up, no increased KL grade was observed in 5 patients; however, an increase by 1 grade was observed in 2 patients and an increase by 2 grades was observed in 1 patient. The Knee injury and Osteoarthritis Outcome Scores at the final follow-up were 87.2 for pain, 87.9 for symptoms, 95.4 for activities of daily living, 79.4 for sports, and 65.6 for quality of life.ConclusionsOlder lateral meniscus allografts obtained from knees of adult patients undergoing total knee arthroplasty and transplanted into younger patients with defects from discoid lateral meniscectomy resulted in improved Lysholm scores but no improvement in Tegner scores or knee motion. KL grades were unchanged in 5 of the 8 patients at the final follow-up.Level of EvidenceIV, therapeutic case series.

Meniscal allograft transplantation shows a mismatch between anatomic and clinical failures.

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

Drug Delivery Systems for the Treatment of Knee Osteoarthritis: A Systematic Review of In Vivo Studies.

Many efforts have been made in the field of nanotechnology to improve the local and sustained release of drugs, which may be helpful to overcome the present limitations in the treatment of knee OA. Nano-/microparticles and/or hydrogels can be now engineered to improve the administration and intra-articular delivery of specific drugs, targeting molecular pathways and pathogenic mechanisms involved in OA progression and remission. In order to summarize the current state of this field, a systematic review of the literature was performed and 45 relevant studies were identified involving both animal models and humans. We found that polymeric nanoparticles loaded with anti-inflammatory drugs (i.e., dexamethasone or celecoxib) are the most frequently investigated drug delivery systems, followed by microparticles and hydrogels. In particular, the nanosystem most frequently used in preclinical research consists of PLGA-nanoparticles loaded with corticosteroids and non-steroidal anti-inflammatory drugs. Overall, improvement in histological features, reduction in joint inflammation, and improvement in clinical scores in patients were observed. The last advances in the field of nanotechnology could offer new opportunities to treat patients affected by knee OA, including those with previous meniscectomy. New smart drug delivery approaches, based on nanoparticles, microparticles, and hydrogels, may enhance the therapeutic potential of intra-articular agents by increasing the permanence of selected drugs inside the joint and better targeting specific receptors and tissues.

Superior Improvements in Knee Pain and Function with a Novel Synthetic Medial Meniscus Replacement Implant Compared to Non-surgical Care in Subjects with Knee Pain Following Partial Meniscectomy: Two-year Results from Two Prospective US Clinical Trials

Objectives:Arthroscopic partial meniscectomy (APM) is the most common surgical treatment for symptomatic, irreparable meniscal tears that do not improve with non-surgical care. For many patients, APM is associated with improvements in knee pain and function, but a subset of patients reports persistent or recurrent knee pain 1-2 years after APM surgery. Current treatment options for post-APM knee pain are limited, especially for patients considered too young for knee replacement. The polymeric medial meniscus implant mimics the biomechanical function of the natural medial meniscus and is intended to provide relief from pain and improved function in subjects with knee pain following APM. Two FDA-regulated clinical trials were conducted in the United States and pooled for analysis, to assess superiority of a synthetic medial meniscus implant to non-surgical care in treating persistent or recurrent knee pain following previous partial meniscectomy. The hypothesis was that the meniscus implant is superior to non-surgical care for improvements in composite measures of knee-related pain, function, and quality of life at 2 years of follow-up.Methods:242 patients (176 investigational, 66 control) were treated in 2 prospective, concurrent clinical trials in the U.S.: a randomized controlled superiority trial (RCT) comparing the medial meniscus implant to non-surgical care (control) and a single-arm, implant-only trial. Eligible subjects had persistent knee pain and one or more previous partial meniscectomies at least 6 months before trial entry. Treated subjects returned for follow-up visits at 1.5 months, 6 months, 1 year, and 2 years. Patient-reported knee pain, function, and quality of life were assessed using the Knee Injury and Osteoarthritis Outcome Score (KOOS). The primary patient-reported outcomes were 2 KOOS subscales: KOOS Pain and KOOS Overall. KOOS success was defined as subjects who achieved either (1) KOOS Pain ≥86.1 at 2 years and KOOS Overall ≥86.2 at 2 years or (2) a ≥20-point improvement from baseline to 2 years in KOOS Pain and KOOS Overall, with KOOS Pain ≥40 at 2 years. Treatment cessation was defined as any subject who discontinued the per-protocol treatment by permanent implant removal (implant group) or any surgical procedure on the index knee (control group). Implant subjects who underwent subsequent surgical procedures on index knees (e.g. implant exchange) remained in the trial. The two treatment groups were well-matched, except for baseline KOOS Sports and Recreation. Statistical analyses adjusted for high vs low baseline KOOS Sports and Recreation using 2-factor analysis of variance (ANOVA) for continuous variables and 2x2 logistic regression for dichotomous variables.Results:Sixteen subjects (6.6%; 14 control, 2 implant) were lost to follow-up or withdrew from the study over 2 years. The magnitude of improvement from baseline to 2 years was significantly greater in the implant group compared to control for 5 of 6 KOOS subscales (Figure 1), including the primary outcomes of KOOS Overall and KOOS Pain (Figure 1A,B). The proportion of subjects who achieved KOOS success was significantly higher in the implant group (63.4%) than the control group (27.9%), which remained true with or without the adjustment for baseline KOOS Sports and Recreation (P<.0001 in each case). Treatment cessation through 2 years was less frequent in the implant group (10.5%) compared to the control group (17.3%), but the difference was not statistically significant (P=.19).Conclusions:Two-year results from 2 prospective, concurrent, US clinical trials demonstrate that the synthetic meniscus implant provides superior relief from post-APM knee pain when compared to treatment with non-surgical care alone. In addition, the magnitude of change from baseline to 2 years in the primary patient-reported outcomes and the rate of KOOS success significantly favored the implant group compared to the control group. Subjects in the implant group tended to discontinue treatment at a lower rate compared to subjects in the control group, but the difference was not statistically significant. Subjects treated with the implant who underwent a device exchange or repositioning procedure were able to continue treatment therapy with the medial meniscus implant. Overall, the implant group experienced superior improvements and outcomes at 2 years compared to subjects receiving non-surgical care alone.

Stiffness after unicompartmental knee arthroplasty: Risk factors and arthroscopic treatment.

Introduction: One of the principal complications after total knee arthroplasty (TKA) is stiffness. There are no publications concerning stiffness after unicompartmental knee arthroplasty (UKA). Study objectives were to describe the incidence of stiffness after UKA, to look for risk factors, and to describe safe and effective arthroscopic treatment. Methods: There were 240 UKA performed between March 2016 and January 2019 included. Robotic-assisted surgery was performed in 164 patients and mechanical instrumentation in 76 patients. Stiffness was defined as flexion < 90° or a flexion contracture > 10° during the first 45 post-operative days. Patients with stiffness were treated with arthroscopic arthrolysis. Several factors were studied to look for risk factors of stiffness: body mass index, gender, age, mechanical or robotic instrumentation, preoperative flexion, previous meniscectomy, and anticoagulant treatment. Arthrolysis effectiveness was evaluated by flexion improvement and UKA revision rate. Results: 22 patients (9%) developed stiffness. Mechanical instrumentation significantly increased the risk of stiffness with OR = 0.26 and p = 0.005. Robotic-assisted surgery decreased the risk of stiffness by five-fold. Before arthrolysis, mean knee flexion was 79°, versus 121° (53% improvement) after arthroscopic arthrolysis. Only 2 patients (9%) underwent UKA revision after arthrolysis. Discussion: Stiffness after UKA is an important complication with an incidence of 9% in this study. Arthroscopic arthrolysis is a safe and effective treatment with a range of motion improvement of > 50%. Robotic-assisted surgery significantly decreases the risk of postoperative stiffness.Level of evidence: Level III, therapeutic study, retrospective cohort study

Postoperative Subchondral Bone Marrow Lesion Is Associated With Graft Extrusion After Lateral Meniscal Allograft Transplantation

Background: Adverse effects of graft extrusion after meniscal allograft transplantation (MAT) are difficult to assess and can be determined only in the long term using a simple radiograph. Recently, subchondral bone marrow lesions (BMLs) detected on magnetic resonance imaging (MRI) scans have been used to evaluate the outcomes or prognoses of various knee surgeries. However, whether subchondral BMLs on MRI scans reflect the effects of allograft extrusion remains unclear. Hypothesis: Subchondral BML in the lateral compartment of the knee joint on postoperative MRI scans would be associated with graft extrusion after lateral MAT. Study Design: Case-control study; Level of evidence, 3. Methods: Overall, 170 patients with lateral MAT between 2008 and 2013 were classified into extrusion (≥3 mm) and nonextrusion (<3 mm) groups based on findings on MRI scans obtained 3 to 6 months postoperatively. Subchondral BMLs in the lateral compartment were evaluated on the latest MRI scans. To exclude any bone marrow signal changes other than those caused by allograft extrusion, the latest MRI scans were compared with those obtained 3 to 6 months postoperatively. Only subchondral BMLs that occurred after that time point were counted. The association between allograft extrusion and subchondral BML was assessed using chi-square analysis. Logistic regression analysis was performed to control other related factors, including age, sex, body mass index, time from previous meniscectomy, alignment, and cartilage status at the time of MAT. Clinical outcomes according to subchondral BML were evaluated using the Lysholm score. Results: Of the 170 patients, 20 (11.8%) had subchondral BML on the latest MRI scans at a mean 53.6 ± 31.2 months postoperatively, with 14 and 6 patients in the extrusion and nonextrusion groups, respectively. Chi-square analysis showed a significant association between allograft extrusion and subchondral BMLs (P = .025). Logistic regression analysis showed that extrusion and age were significant factors associated with subchondral BML (P = .011 and .004, respectively). However, no differences were observed in the Lysholm scores in accordance with the subchondral BML (P = .248). Conclusion: Subchondral BMLs on postoperative MRI scans were associated with graft extrusion after lateral MAT. However, there was no difference in clinical outcomes according to subchondral BML.

Measures of Adult Knee Function.

Measures of Adult Knee Function.

Meniscal scaffold for the treatment of partial meniscal defect-clinical and radiological outcomes in a two-year follow-up.

The aim of meniscal scaffolds is to fill the defect, allow regeneration of meniscal-like tissues, and to prevent long-term risk of cartilage wear and tear. The aim of this study was to evaluate clinical results after two years and magnetic resonance imaging (MRI) results a year after implantation of a meniscal scaffold. Fifteen patients were recruited into a prospective, single-arm, single-center study, and treated with meniscal scaffolds as a result of segmentalmeniscal defect due to previous partial meniscectomy. Patients were evaluated using functional knee scores used pre-operatively and 6, 12, and 24 monthspostoperatively. The radiological outcome was assessed using MRI at 12 months by evaluating scaffold size, morphology, and intensity according to theGenovese grading system. Cartilage assessment was completed according to The International Cartilage Repair Society (ICRS) score. All patients completed a follow-up of 24months. A statistically significant increase in mean levels of all functional scores was present in all patients. On the MRI, all but one of the patients presented an incorporated meniscal implant. In most of the patients (73%), the meniscal implant was a Genovese type III. Type II and III signal intensities were present in all scaffolds when compared with the residual meniscal tissue. A stable cartilage (ICRS) status was observed in 80% of the patients compared with the pre-operative cartilage scores. In our case series of patients treated with the meniscal scaffold implant, we observed good clinical results at a twoyear follow-up. Furthermore, MRI findings suggest that meniscal scaffolds might have a beneficial effect on articular cartilage.

Does Age Itself Have an Adverse Effect on Survivorship of Meniscal Allograft Transplantation? A Cartilage Status and Time From Previous Meniscectomy–Matched Cohort Study

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

Lateral meniscal slope negatively affects post-operative anterior tibial translation at 1 year after primary anterior cruciate ligament reconstruction.

The aim of this study was to assess the correlation between posterior tibial slope and meniscal slope over postoperative anterior tibial translation during the first 18months after primary anterior cruciate ligament (ACL) reconstruction. The main hypothesis was that PTS and MS would be positively correlated with post-operative ATT-SSD after ACL reconstruction. Patients (28 males and 15 females) with confirmed ACL tears were selected from an in-house registry and included if they were over 16years old, had primary ACL-reconstruction and healthy contralateral knee. Patients meeting one of the following criteria were excluded: previous knee surgeries, intraarticular fractures, associated ligamentous lesions, previous or concomitant meniscectomy or extraarticular procedures. Lateral posterior tibial slope, medial posterior tibial slope, lateral meniscal slope and medial meniscal slope were measured using preoperative MRIs. The side-to-side-difference in anterior tibial translation was evaluated 9-18months postoperatively. Forty-three patients were included, (28 males/15 females; mean age 25 ± 8years). Mean postoperative anterior tibial translation was 1.0 ± 1.1mm at a mean time of 12 ± 1months. Mean slope values were: lateral posterior tibial slope 4.7° ± 2.2°, medial posterior tibial slope 4.0° ± 2.8°, lateral meniscal slope 3.0° ± 2.2° and medial meniscal slope 2.0° ± 2.8°. The anterior tibial translation was significantly correlated with lateral meniscal slope (r = 0.63; p < 0.01). For each 1° increase in lateral meniscal slope, a 0.3mm 95% CI [0.2, 0.4] (p < 0.01) increase in anterior tibial translation was observed. A lateral meniscal slope greater or equal to 4.0° was estimated as optimal threshold for increased risk of abnormal side-to-side difference in postoperative anterior tibial translation (≥ 1.2mm). The lateral meniscal slope was positively correlated to side-to-side difference in anterior tibial translation after primary ACL reconstruction. A lateral meniscal slope greater or equal to 4.0° was detected as threshold for an increased risk of abnormal side-to-side difference in postoperative anterior tibial translation in patients who underwent primary ACL reconstruction. This confirms that soft tissue slopes have an impact on the outcomes after reconstructive surgery. Level of evidence III.