Current concepts in meniscus surgery: resection to replacement

Functionalized hydrogels as smart gene delivery systems to treat musculoskeletal disorders

Despite critical advances in regenerative medicine, the generation of definitive, reliable treatments for musculoskeletal diseases remains challenging. Gene therapy based on the delivery of therapeutic genetic sequences has strong value to offer effective, durable options to decisively manage such disorders. Furthermore, scaffold-mediated gene therapy provides powerful alternatives to overcome hurdles associated with classical gene therapy, allowing for the spatiotemporal delivery of candidate genes to sites of injury. Among the many scaffolds for musculoskeletal research, hydrogels raised increasing attention in addition to other potent systems (solid, hybrid scaffolds) due to their versatility and competence as drug and cell carriers in tissue engineering and wound dressing. Attractive functionalities of hydrogels for musculoskeletal therapy include their injectability, stimuli-responsiveness, self-healing, and nanocomposition that may further allow to upgrade of them as "intelligently" efficient and mechanically strong platforms, rather than as just inert vehicles. Such functionalized hydrogels may also be tuned to successfully transfer therapeutic genes in a minimally invasive manner in order to protect their cargos and allow for their long-term effects. In light of such features, this review focuses on functionalized hydrogels and demonstrates their competence for the treatment of musculoskeletal disorders using gene therapy procedures, from gene therapy principles to hydrogel functionalization methods and applications of hydrogel-mediated gene therapy for musculoskeletal disorders, while remaining challenges are being discussed in the perspective of translation in patients. STATEMENT OF SIGNIFICANCE: Despite advances in regenerative medicine, the generation of definitive, reliable treatments for musculoskeletal diseases remains challenging. Gene therapy has strong value in offering effective, durable options to decisively manage such disorders. Scaffold-mediated gene therapy provides powerful alternatives to overcome hurdles associated with classical gene therapy. Among many scaffolds for musculoskeletal research, hydrogels raised increasing attention. Functionalities including injectability, stimuli-responsiveness, and self-healing, tune them as "intelligently" efficient and mechanically strong platforms, rather than as just inert vehicles. This review introduces functionalized hydrogels for musculoskeletal disorder treatment using gene therapy procedures, from gene therapy principles to functionalized hydrogels and applications of hydrogel-mediated gene therapy for musculoskeletal disorders, while remaining challenges are discussed from the perspective of translation in patients.

Early Surgery Versus Exercise Therapy and Patient Education for Traumatic and Nontraumatic Meniscal Tears in Young Adults-An Exploratory Analysis From the DREAM Trial

OBJECTIVE: To compare the effect of early meniscal surgery versus exercise and education with the option of later surgery on pain, function, and quality of life in young patients with a meniscal tear, taking symptom onset into account. DESIGN: Randomized controlled trial. METHODS: In a randomized controlled trial (the "Danish RCT on Exercise versus Arthroscopic Meniscal surgery for young adults" [DREAM] trial), 121 patients aged 18-40 years with a magnetic resonance imaging-verified meniscal tear were randomized to surgery or 12 weeks of supervised exercise and patient education. For this exploratory study, the analyses were stratified by symptom onset (traumatic/nontraumatic). The main outcome was the difference in change after 12 months in the mean score of 4 Knee injury and Osteoarthritis Outcome Score subscales (KOOS4) covering pain, symptoms, function in sport and recreation, and quality of life. RESULTS: Forty-two patients (69%) in the exercise therapy group and 47 (78%) in the surgery group were categorized as having a traumatic tear. We observed no difference in change in the KOOS4 after 12 months between the 2 treatment groups for either traumatic tears (18.8 versus 16.0 in the surgery versus exercise therapy groups; adjusted mean difference, 4.8 [95% confidence interval, -1.7 to 11.2]) or nontraumatic tears (20.6 versus 17.3 in the surgery versus exercise therapy groups; adjusted mean difference, 7.0 [95% confidence interval, -3.7 to 17.7]). CONCLUSION: In patients with traumatic and nontraumatic meniscus tears, early meniscal surgery did not appear superior to exercise and education in improving pain, function, and quality of life after 12 months. Further research is needed to confirm the clinical applicability of these findings. J Orthop Sports Phys Ther 2024;54(5):1-10. Epub 22 February 2024. doi:10.2519/jospt.2024.12245.

Ontogeny of the meniscus in the anuran Xenopus laevis

The anuran knee joint is subjected to the jump, one of the tetrapods' most demanding mechanical stresses. Consistent with this continuous effort, the knee of the anurans has a complex structure comparable to that of an amniote. Here, we describe the ontogeny of the Xenopus knee tissues and study the morphogenesis of the knee joint shape by performing a geometric morphometric analysis of specially selected anatomical structures: the menisci and the long bone epiphyses. A meniscus is a crescent-shaped fibrocartilaginous structure, with a triangular cross-section inserted between joints surfaces. A meniscus transmits load across the tibiofemoral joint by increasing congruity of the long bone epiphysis and decreasing the resulting stress exerted on the articular cartilage. We ask two questions: (1) what is the tissue composition along the ontogeny of the menisci of a swimming frog? (2) How do the menisci acquire the shape that will allow their adjustment? We studied the structures and tissue ontogeny of the knee of several specimens of Xenopus laevis and evaluated the congruity of the knee structures across the species ontogeny. Histological sections showed that the cavitation process responsible for separating the menisci and the epiphyses seems to be pivotal in shaping the conformity of these structures and the long bone epiphyses of the hindlimbs. The geometric morphometric analysis allowed us to interpret three phases of differentiation associated with limb functionality. The characteristic shape of the meniscus appears early in the ontogeny of the knee, simultaneously with the epiphysis contours.

Early Surgery or Exercise and Education for Meniscal Tears in Young Adults

BACKGROUND: Surgery is commonly used to treat meniscal tears; however, to our knowledge, no randomized controlled trials (RCTs) have compared surgery with nonsurgical alternatives in young adults. We hypothesized that early meniscal surgery would be superior to a strategy of exercise and education with the option of surgery later if needed. METHODS: In this pragmatic parallel-group RCT, we enrolled young adults (18-40 years of age) with magnetic resonance imaging–verified meniscal tears eligible for surgery from seven Danish hospitals. Patients were randomly assigned (1:1) to surgery (partial meniscectomy or meniscal repair) or 12-week supervised exercise therapy and education with the option of surgery later if needed. The primary outcome was the difference in change from baseline to 12 months in the mean score of four Knee Injury and Osteoarthritis Outcome Score (KOOS4) subscales covering pain, symptoms, function in sport and recreation, and quality of life, ranging from 0 (worst) to 100 (best). RESULTS: We enrolled 121 young adults (mean age, 29.7 years; 28% were female). In total, 107 participants (88%) completed the 12-month follow-up; 16 participants (26%) from the exercise group crossed over to surgery, while 8 (13%) from the surgery group did not undergo surgery. Intention-to-treat analysis showed no statistically significant difference in change between groups from baseline to 12 months in KOOS4 scores (19.2 vs. 16.4 in the surgery vs. exercise groups; adjusted mean difference, 5.4 [95% confidence interval, −0.7 to 11.4]). No difference in serious adverse events was observed (four vs. seven in the surgery and exercise groups, respectively; P=0.40). Per-protocol and as-treated analyses yielded similar results. CONCLUSIONS: Our results suggest that among young, active adults with meniscal tears, a strategy of early meniscal surgery is not superior to a strategy of exercise and education with the option of later surgery. Both groups experienced clinically relevant improvements in pain, function, and quality of life at 12 months, and one of four from the exercise group eventually had surgery. (Funded by the Danish Council for Independent Research, IMK Almene Fond, Lundbeck Foundation, Spar Nord Foundation, Danish Rheumatism Association, Association of Danish Physiotherapists Research Fund, Research Council at Næstved-Slagelse-Ringsted Hospitals, and Region Zealand; ClinicalTrials.gov number, NCT02995551.)

Meniscal Allograft Transplantation: A Pictorial Review

Meniscal allograft transplantation may be indicated in a subset of patients with high-grade meniscectomy or irreparable meniscal injury and persistent knee pain that is resistant to conservative management. Meniscal allograft transplantation has demonstrated good to excellent results in short-term to midterm follow-up studies and satisfactory outcomes in long-term studies. The goals of this article are to review the indications, preoperative imaging assessment, surgical techniques, and postoperative assessment of uncomplicated and complicated meniscal allograft transplants.

Evaluation of Meniscal Tissue after Meniscal Repair Using Ultrahigh Field MRI

The study evaluates the meniscal tissue after primary meniscal suturing using 7-Tesla (T) magnetic resonance imaging with T₂* mapping at 6 and 12 months after surgery to investigate the differences between repaired meniscal tissue and healthy meniscal tissue in the medial and lateral compartment. This prospective study included 11 patients (9m/2f) with a mean age of 30.6 years (standard deviation 9.0). Patients with a meniscal tear that was treated arthroscopically with meniscus suturing, using an all-inside technique, were included. All patients and seven healthy volunteers were imaged on a 7-T whole-body system. T2* mapping of the meniscus was applied on sagittal slices. Regions-of-interest were defined manually in the red and white zone of each medial and lateral meniscus to measure T2*-values. In the medial posterior and medial anterior horn similar T₂*-values were measured in the red and white zone at 6- and 12-month follow-up. Compared with the control group higher T₂*-values were found in the repaired medial meniscus. After 12-months T₂*-values decreased to normal values in the anterior horn and remained elevated in the posterior horn. In the red zone of the lateral posterior horn a significant decrease in the T₂*-values (from 8.2 milliseconds to 5.9 milliseconds) (p = 0.04), indicates successful repair; a tendency toward a decrease in the white zone between the 6 and 12 months follow-up was observed. In the red zone of the lateral anterior horn the T₂*-values decreased significantly during follow-up and in the white zone of the lateral anterior horn T₂*-values were comparable. In comparison to the control group higher T₂*-values were measured at 6-months; however, the T₂*-values showed comparable values in the repaired lateral meniscus after 12 months. The T2* mapping results of the current study indicated a better healing response of the red zone of the lateral posterior horn compared with the medial posterior horn.

Functional Characteristics and Mechanical Performance of PCU Composites for Knee Meniscus Replacement

The potential use of fiber-reinforced based polycarbonate-urethanes (PCUs) as candidate meniscal substitutes was investigated in this study. Mechanical test pieces were designed and fabricated using a compression molding technique. Ultra-High Molecular Weight Polyethylene (UHMWPE) fibers were impregnated into PCU matrices, and their mechanical and microstructural properties evaluated. In particular, the tensile moduli of the PCUs were found unsuitable, since they were comparatively lower than that of the meniscus, and may not be able to replicate the inherent role of the meniscus effectively. However, the inclusion of fibers produced a substantial increment in the tensile modulus, to a value within a close range measured for meniscus tissues. Increments of up to 227% were calculated with a PCU fiber reinforcement composite. The embedded fibers in the PCU composites enhanced the fracture mechanisms by preventing the brittle failure and plastic deformation exhibited in fractured PCUs. The behavior of the composites in compression varied with respect to the PCU matrix materials. The mechanical characteristics demonstrated by the developed PCU composites suggest that fiber reinforcements have a considerable potential to duplicate the distinct and multifaceted biomechanical roles of the meniscus.

Tissue healing following segmental meniscal allograft transplantation: a pilot study

PURPOSE

This in vivo histological study using an ovine model evaluated the 90-day healing of unilateral segmental meniscal allograft transplantation.

METHODS

Fresh-frozen medial menisci were transplanted to replace the right medial meniscus of six female sheep. Tissue healing was evaluated using semi-quantitative, descriptive methods. Formalin-fixed meniscal, distal femur and proximal tibia tissues were evaluated using Rodeo (cellularity/collagen), Ishida (reparative bonding), Collagen I IHC (collagen I), and Mankin (cartilage organization) scores at the medial femoral condyle (MFC) and medial tibial plateau (MTP). Meniscocapsular evaluations were performed at the: (a) peripheral junction; (b) posterior sector-native meniscus junction; (c) anterior sector-native meniscus junction; (d) posterior horn internal control; and (e) anterior horn internal control.

RESULTS

Three animals were euthanized at 39 ± 2.6 days post-surgery because of their knee condition. These animals had moderate Rodeo scores, low Ishida scores, and high Collagen I staining scores indicating moderately high fibrocartilaginous changes, mild or minimal healing and high collagen I content. Cartilage scores were low in the MFC and moderately high in the MTP, indicating mild MFC cartilage changes and moderately high MTP cartilage changes. Full-term (90 day) euthanized animals (n = 3) displayed improving Rodeo scores with mean scores of 3.3 and 3.6 at junctions (B) and (C), respectively. Ishida scores displayed similar improvements at all sectors. Collagen I staining revealed strong (grade 5) levels in all sections, with mean collagen I scores of 5, 5 and 4 for the peripheral (A), posterior (B) and anterior (C) junctions, respectively. Improved healing was observed at each segmental meniscus sector in terminally euthanized animals.

CONCLUSIONS

Segmental meniscal allograft transplantation displayed partial healing to remnant meniscal tissue. Further study is needed to better delineate the time needed for complete healing and the joint-loading progression that may enhance it.

Modeling-Based Assessment of 3D Printing-Enabled Meniscus Transplantation

3D printing technology is able to produce personalized artificial substitutes for patients with damaged menisci. However, there is a lack of thorough understanding of 3D printing-enabled (3DP-enabled) meniscus transplantation and its long-term advantages over traditional transplantation. To help health care stakeholders and patients assess the value of 3DP-enabled meniscus transplantation, this study compares the long-term cost and risk of this new paradigm with traditional transplantation by simulation. Pathway models are developed to simulate patients' treatment process during a 20-year period, and a Markov process is used to model the state transitions of patients after transplantation. A sensitivity analysis is also conducted to show the effect of quality of 3D-printed meniscus on model outputs. The simulation results suggest that the performance of 3DP-enabled meniscus transplantation depends on quality of 3D-printed meniscus. The conclusion of this study is that 3DP-enabled meniscus transplantation has many advantages over traditional meniscus transplantation, including a minimal waiting time, perfect size and shape match, and potentially lower cost and risk in the long term.

Materials and structures used in meniscus repair and regeneration: a review

Meniscus is a vital functional unit in knee joint. It acts as a lubricating structure, a nutrient transporting structure, as well as shock absorber during jumping, twisting and running and offers stability within the knee joint. It helps in load distribution, in bearing the tensile hoop stresses and balancing by providing a cushion effect between hard surfaces of two bones. Meniscus may be injured in sports, dancing, accident or any over stressed condition. Any meniscal lesion can lead to a gradual development of osteoarthritis or erosion of bone contact surface due to disturbed load and contact stress distribution caused by injury/pain. Once injured, the possibilities of self-repair are rare in avascular region of meniscus, due to lack of blood supply in avascular region. Meniscus has vascular and avascular regions in structure. Majority of the meniscus parts turn avascular with increase in age.

Purpose of this review is to highlight advances in meniscus repair with special focus on tissue engineering using textile/fiber based scaffolds, as well as the recent technical advances in scaffolds for meniscus recon- struction/ regeneration treatment.

Annual trends in arthroscopic meniscus surgery: Analysis of a national database in Japan

Background

The importance of meniscus preservation is widely recognized. There have been a few studies describing trends in meniscectomy and meniscus repair in the United States; however, they presented differing results. We reported annual trends in meniscus surgery, using a national database in Japan.

Methods

We interrogated the Diagnosis Procedure Combination database, which represents approximately half of all hospital admissions in Japan. We included the patients who underwent meniscectomy and meniscus repair between July 2007 and March 2015. The diagnosis, age and sex of each patient were recorded.

Results

We identified 83,105 patients: 69,310 underwent meniscectomy; 13,416 underwent meniscus repair and 379 underwent both in a single admission. The proportion of patients undergoing meniscus repair rose from 7.0% in 2007 to 25.9% in 2014 (p < 0.001), while the proportion undergoing meniscectomy fell from 92.8% in 2007 to 73.3% in 2014 (p < 0.001). Among patients under 30 years old, the proportions undergoing meniscus repair or meniscectomy in 2014 were 50.3% versus 48.3%, respectively. A bimodal age distribution was observed for meniscectomy, with peaks at 10–19 years of age and 60–69 years of age, whereas most patients undergoing meniscus repair were 10–19 years of age.

Conclusions

We found characteristic trends where the popularity of meniscus repair increased rapidly at the expense of meniscectomy in Japan during the study period. In the last survey year, the proportion of meniscus repair exceeded that of meniscectomy in those younger than 30 years. Meniscectomy was undertaken most often in adolescents and early old age, while meniscus repair was undertaken most often in adolescents.

Development of a Chinese version of the Western Ontario Meniscal Evaluation Tool: cross-cultural adaptation and psychometric evaluation

Background

The Western Ontario Meniscal Evaluation Tool (WOMET) is a questionnaire designed to evaluate the health-related quality of life (HRQOL) of patients with meniscal pathology. Our study aims to culturally adapt and validate the WOMET into a Chinese version.

Methods

We translated the WOMET into Chinese. Then, a total of 121 patients with meniscal pathology were invited to participate in this study. To assess the test-retest reliability, the Chinese version WOMET was completed twice at 7-day intervals by the participants. The construct validity was assessed using Pearson’s correlation coefficient or Spearman’s correlation to test for correlations among the Chinese version WOMET and the eight domains of Short Form-36 (SF-36), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the International Knee Documentation Committee (IKDC) score. Responsiveness was tested by comparison of the preoperative and postoperative scores of the Chinese version WOMET.

Results

The test-retest reliability of the overall scale and different domains were all found to be excellent. The Cronbach’s α was 0.90. The Chinese version WOMET correlated well with other questionnaires which suggested good construct validity. We observed no ceiling and floor effects of the Chinese version WOMET. We also found good responsiveness for the effect size, and the standardized response mean values were 0.86 and 1.11.

Conclusions

The Chinese version of the WOMET appears to be reliable and valid in evaluating patients with meniscal pathology.

Meniscal Ramp Lesions: Anatomy, Incidence, Diagnosis, and Treatment

Meniscal ramp lesions are more frequently associated with anterior cruciate ligament (ACL) injuries than previously recognized. Some authors suggest that this entity results from disruption of the meniscotibial ligaments of the posterior horn of the medial meniscus, whereas others support the idea that it is created by a tear of the peripheral attachment of the posterior horn of the medial meniscus. Magnetic resonance imaging (MRI) scans have been reported to have a low sensitivity, and consequently, ramp lesions often go undiagnosed. Therefore, to rule out a ramp lesion, an arthroscopic evaluation with probing of the posterior horn of the medial meniscus should be performed. Several treatment options have been reported, including nonsurgical management, inside-out meniscal repair, or all-inside meniscal repair. In cases of isolated ramp lesions, a standard meniscal repair rehabilitation protocol should be followed. However, when a concomitant ACL reconstruction (ACLR) is performed, the rehabilitation should follow the designated ACLR postoperative protocol. The purpose of this article was to review the current literature regarding meniscal ramp lesions and summarize the pertinent anatomy, biomechanics, diagnostic strategies, recommended treatment options, and postoperative protocol.

Surgical Trends in the Treatment of Meniscal Tears: Analysis of Data From the American Board of Orthopaedic Surgery Certification Examination Database

BACKGROUND

The indications and criteria for meniscal repair are expanding in parallel with new understanding in biomechanics, joint pathophysiology, and increased physician education.

PURPOSE

To describe the practice patterns of arthroscopic meniscal treatment in recent years, compare the trends of arthroscopic meniscal repair versus arthroscopic meniscectomy, and compare sports fellowship-trained versus non-sports fellowship-trained surgeons in terms of arthroscopic meniscal treatment techniques among American Board of Orthopaedic Surgery (ABOS) candidates from 2004 to 2012.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

The ABOS database was used to identify cases of meniscal repair, partial meniscectomy, and anterior cruciate ligament (ACL) reconstruction from 2004 to 2012. The number of surgeons contributing cases for each calendar year was also recorded, along with the number who had sports fellowship training. Rates were calculated as the number of procedures per surgeon per year. Trends were analyzed using Poisson regression analysis to model the rate of each procedure over time.

RESULTS

The rate of all meniscal procedures per surgeon decreased 12% from 18.4 cases per surgeon in 2004 to 16.2 cases per surgeon in 2012. There was a smaller decrease for sports fellowship-trained surgeons (7%) than for non-sports fellowship-trained surgeons (32%). The rate of meniscal repair cases per surgeon increased 37% from 1.6 to 2.2 cases per surgeon. The rate of meniscectomy cases decreased 17% from 16.8 to 14.0 cases per surgeon. When comparing fellowship-trained surgeons to non-fellowship-trained surgeons, there was no significant difference in meniscal repair rates over time. There was a decrease of 35% in rates of meniscectomy among non-fellowship-trained surgeons compared with 11% among fellowship-trained surgeons.

CONCLUSION

This study provides insight into the current practice trends of recent orthopaedic training graduates in the treatment of meniscal tears. The results suggest that reported meniscal procedures have decreased overall among ABOS candidates but that meniscal repair cases have increased. The findings support the recent shift toward evidence-based medicine, with changing practice patterns that may reflect the dissemination of recent findings from large, high-quality research studies in this field.

The Optimal Suture Site for the Repair of Posterior Horn Root Tears: Biomechanical Evaluation of Pullout Strength in Porcine Menisci

PURPOSE

There are few studies on biomechanical evaluation of suture points in repair of root tears. The purpose of this study was to determine the point of greatest pullout strength for root tear repair.

MATERIALS AND METHODS

A total of 120 fresh porcine medial menisci were obtained. The red-red and red-white zones of the meniscus were divided by two lines designated as lines A and B (groups A and B). Groups A and B were further divided into three groups each by dividing lines A and B into three points: 3, 5, and 7 mm from the meniscal ligament root insertion. Vertical meniscal repair was performed on each point. The pullout failure strength was tested using a biaxial servohydraulic testing machine.

RESULTS

The average maximal load at failure was significantly greater in group A than group B (87.65 vs. 62.93; p<0.001) The average length at maximal load failure was greater in group A than group B (4.35 vs. 3.2; p<0.001). Among the subgroups of 3, 5, and 7 mm in both groups A and B, 7 mm showed the greatest maximal load (p<0.001).

CONCLUSIONS

The pullout strength was statistically significantly greater in group A than group B and in the 7 mm subgroup than the 3 and 5 mm subgroups. Thus, the 7 mm subgroup in group A showed the greatest pullout strength.

Meniscal transplant in children

PURPOSE OF REVIEW

The purpose is to review and discuss the fundamentals, indications, surgical technique, controversies, and outcomes regarding meniscal transplantation, focusing on available evidence in pediatric populations.

RECENT FINDINGS

Recent studies have confirmed meniscal allograft transplantation as an effective procedure to improve symptoms, knee function, and quality of life following meniscectomy, particularly in symptomatic young patients. Associated procedures, such as osteotomies and cartilage-related surgeries, have expanded the indications for transplantation. Most patients return to sports following meniscal transplantation, and the procedure does not preclude the potential return to high-level athletic competition. The chondroprotective effect of transplantation has not been proven and as a result the role of prophylactic transplantation remains unclear.

SUMMARY

Meniscal allograft transplantation is indicated following symptomatic meniscal loss in young, active patients to relieve pain and improve knee function. The quality of the available evidence regarding meniscal transplantation is limited, and no published series to date has focused exclusively on a pediatric population. Further high-quality studies are needed to establish improved indications, timing, and outcomes in a pediatric population.

Meniscal allograft transplantation

The anatomy and microstructure of the menisci allow the effective distribution of load across the knee. Meniscectomy alters the biomechanical environment and is a potent risk factor for osteoarthritis. Despite a trend towards meniscus-preserving surgery, many tears are irreparable, and many repairs fail.

Meniscal allograft transplantation has principally been carried out for pain in patients who have had a meniscectomy. Numerous case series have reported a significant improvement in patient-reported outcomes after surgery, but randomised controlled trials have not been undertaken.

It is scientifically plausible that meniscal allograft transplantation is protective of cartilage, but this has not been established clinically to date.

Cite this article: Bone Joint J 2015; 97-B:590–4.

Meniscal repair

The meniscus has several important roles, such as transmission of the load, absorption of the shock in the knee joint, acting as a secondary anteroposterior stabilizer of the knee joint, and contributing to proprioception of the knee joint. Degenerative changes of the knee joint develop in the long-term follow-up even after partial meniscectomy. Thus, there has been growing interest in meniscal repair. In addition, with increased understanding of the important roles of the meniscal root and advancement of diagnostic methods, efforts have been made to ensure preservation of the meniscal roots. In this review article, we will discuss operative techniques and clinical outcomes of arthroscopic repair of the meniscus and the meniscal root and postoperative rehabilitation and complications as well.

Pullout failure strength of the posterior horn of the medial meniscus with root ligament tear

PURPOSE

To evaluate the reparability of the posterior horn of the medial meniscus with root ligament tear by measuring the actual pullout failure strength of a simple vertical suture of an arthroscopic subtotal meniscectomized posterior horn of the medial meniscus.

METHODS

From November 2009 to May 2010, nine posterior horns of the medial meniscus specimens were collected from arthroscopic subtotal meniscectomy performed as a treatment for root ligament rupture of the posterior horn of the medial meniscus. Simple vertical sutures were performed on the specimens, and pullout failure load was tested with a biaxial servohydraulic testing machine (Model 8874; Instron Corp., Norwood, MA, USA). The degree of degeneration, extrusion, and medial displacement of the medial meniscus were evaluated with magnetic resonance imaging (MRI). The Kellgren-Lawrence classification was used in standing plain radiography, and mechanical alignment was measured using orthoroentgenography. Tear morphology was classified into ligament proper type or meniscoligamentous junctional type according to the site of the torn root ligament of the posterior horn of the medial meniscus during arthroscopy.

RESULTS

The mean pullout failure strength of the posterior horn of the medial meniscus was 71.6 ± 23.2 N (range, 41.4-107.7 N). The degree of degeneration of the posterior horn of the medial meniscus on MRI showed statistically significant correlation with pullout failure strength and Kellgren-Lawrence classification. Pullout failure strength showed correlation with mechanical alignment and Kellgren-Lawrence classification (P < 0.05).

CONCLUSIONS

The measurement of pullout failure strength of the posterior horn of the medial meniscus with root ligament tear showed a degree of repairability. The degree of degeneration of the posterior horn of the medial meniscus on MRI showed a significant correlation with the pullout failure strength. The pullout failure strength was also not only correlated with the degree of degeneration of the posterior horn of the medial meniscus, but also with mechanical alignment and Kellgren-Lawrence classification, which represent bony degenerative change.

Meniscal injuries and imaging the postoperative meniscus

Meniscal injuries are common. Magnetic resonance imaging is considered the imaging modality of choice in diagnosing meniscal pathologic conditions in the nonoperative knee. Meniscal-preserving surgery is becoming more frequent, with a resultant increase in postoperative meniscal imaging, which is particularly challenging for the reporting radiologist. This article provides a review of the anatomy, pathologic conditions, and diagnostic pitfalls of meniscal injury, with a synopsis of the issues faced with postoperative meniscal imaging.

Intra-articular injection of human mesenchymal stem cells (MSCs) promote rat meniscal regeneration by being activated to express Indian hedgehog that enhances expression of type II collagen

OBJECTIVE

Meniscal regeneration was previously shown to be enhanced by injection of mesenchymal stem/stromal cells (MSCs) but the mode of action of the MSCs was not established. The aim of this study was to define how injection of MSCs enhances meniscal regeneration.

DESIGN

A hemi-meniscectomy model in rats was used. Rat-MSCs (rMSCs) or human-MSCs (hMSCs) were injected into the right knee joint after the surgery, and PBS was injected into the left. The groups were compared macroscopically and histologically at 2, 4, and 8 weeks. The changes in transcription in both human and rat genes were assayed by species-specific microarrays and real-time RT-PCRs.

RESULTS

Although the number of hMSCs decreased with time, hMSCs enhanced meniscal regeneration in a manner similar to rMSCs. hMSCs injection increased expression of rat type II collagen (rat-Col II), and inhibited osteoarthritis progression. The small fraction of hMSCs was activated to express high levels of a series of genes including Indian hedgehog (Ihh), parathyroid hormone-like hormone (PTHLH), and bone morphogenetic protein 2 (BMP2). The presence of hMSCs triggered the subsequent expression of rat-Col II. An antagonist of hedgehog signaling inhibited the expression of rat-Col II and an agonist increased expression of rat-Col II in the absence of hMSCs.

CONCLUSIONS

Despite rapid reduction in cell numbers, intra-articular injected hMSCs were activated to express Ihh, PTHLH, and BMP2 and contributed to meniscal regeneration. The hedgehog signaling was essential in enhancing the expression of rat-Col II, but several other factors provided by the hMSCs probably contributed to the repair.

Meniscal repair using the inside-out technique with cross stitch

The treatment of meniscal tears continues to evolve. A few years ago most tears were treated with total meniscectomy, which evolved to partial meniscectomy and then to meniscal repair. The purpose is to preserve as much of the menisci as possible, to maintain their potential biomechanical properties, and to preserve normal knee function. Different repair techniques have been used many of them involving both vertical and horizontal sutures. We are proposing an inside-out meniscal repair technique with cross-shaped stitches that provides a 4-point fixation construct.

Surgical decision making for arthroscopic partial meniscectomy in patients aged over 40 years

PURPOSE

To identify clinical variables that affect a surgeon's decision to recommend arthroscopic partial meniscectomy (APM).

METHODS

Members of 2 orthopaedic specialty societies were invited to participate in an online survey by e-mail. The survey consisted of surgeon demographics and case scenarios to evaluate clinical decision making for APM. Posterior probabilities were calculated to determine the effect of clinical factors on the likelihood of recommending APM.

RESULTS

Of the respondents with valid e-mail addresses, 733 (19.3%) returned a completed survey, but only 533 (14.1%) met the eligibility criteria (treated or referred an APM candidate within the past year). Respondents were aged 46.7 ± 9.4 and had performed a mean of 115 APMs in the previous year. Posterior probabilities for a combination of 6 clinical indicators identified 3 factors that most influenced a surgeon's decision to recommend APM: radiographic findings, McMurray test, and failure of nonoperative management.

CONCLUSIONS

Significant variation exists among practicing orthopaedic surgeons with regard to decision making for APM. The 3 clinical factors that most influenced a surgeon's decision to recommend APM were normal radiographic findings, failed nonoperative treatment, and the presence of positive physical examination findings (i.e., positive McMurray test, joint line tenderness, and effusion).

LEVEL OF EVIDENCE

Level III, decision analysis.

Rehabilitation following meniscal repair

It has become increasingly more evident that the meniscus plays an important role in contributing to knee joint longevity. Advances in surgical techniques by orthopaedic surgeons to repair traumatized menisci have led to better long term outcomes, decreasing the incidence of articular cartilage degeneration. Advances have also been made in rehabilitative techniques following meniscal repair. These techniques along with sound rehabilitation principles to include a criteria based progression have contributed to excellent outcomes and earlier return to function and sport. The role of the meniscus, recent advances in surgical repair and the current post-operative rehabilitation techniques employed by sports rehabilitation specialists today are discussed.

Cell-based meniscal tissue engineering: a case for synoviocytes

BACKGROUND

Avascular meniscal injuries are largely incapable of healing; the most common treatment remains partial meniscectomy despite the risk of subsequent osteoarthritis. Meniscal responses to injury are partially mediated through synovial activity and strategies have been investigated to encourage healing through stimulating or transplanting adjacent synovial lining. However, with their potential for chondrogenesis, synovial fibroblast-like stem cells hold promise for meniscal cartilage tissue engineering.

QUESTIONS/PURPOSES

Thus, specific purposes of this review were to (1) examine how the synovial intima and synoviomeniscal junction affect current meniscal treatment modalities; and (2) examine the components of tissue engineering (cells, scaffolds, bioactive agents, and bioreactors) in the specific context of how cells of synovial origin may be used for meniscal healing or regeneration.

METHODS

An online bibliographic search through PubMed was performed in March 2010. Studies were subjectively evaluated and reviewed if they addressed the question posed. Fifty-four resources were initially retrieved, which offered information on the chondrogenic potential of synovial-based cells that could prove valuable for meniscal fibrocartilage engineering.

RESULTS

Based on the positive effects of adjoining synovium on meniscal healing as used in some current treatment modalities, the chondrogenic potential of fibroblast-like stem cells of synovial origin make this cell source a promising candidate for cell-based tissue engineering strategies.

CONCLUSIONS

The abundance of autologous synovial lining, its ability to regenerate, and the potential of synovial-derived stem cells to produce a wide spectrum of chondral matrix components make it an ideal candidate for future meniscal engineering investigations.

Prospective long-term outcomes of the medial collagen meniscus implant versus partial medial meniscectomy: a minimum 10-year follow-up study

BACKGROUND

Loss of meniscal tissue can be responsible for increased pain and decreased function.

HYPOTHESIS

At a minimum 10-year follow-up, patients receiving a medial collagen meniscus implant (MCMI) would show better clinical, radiological, and magnetic resonance imaging (MRI) outcomes than patients treated with partial medial meniscectomy (PMM).

STUDY DESIGN

Cohort study; Level of evidence 2.

METHODS

Thirty-three nonconsecutive patients (men; mean age, 40 years) with meniscal injuries were enrolled in the study to receive MCMI or to serve as a control patient treated with PMM. The choice of treatment was decided by the patient. All patients were clinically evaluated at time 0 and at 5 years and a minimum of 10 years after surgery (mean follow-up, 133 months) by Lysholm, visual analog scale (VAS) for pain, objective International Knee Documentation Committee (IKDC) knee form, and Tegner activity level scores. The SF-36 score was performed preoperatively and at final follow-up. Bilateral weightbearing radiographs were completed before the index surgery and at final follow-up. Minimum 10-year follow-up MRI images were compared with preoperative MRI images by means of the Yulish score. The Genovese score was also used to evalute MCMI MRI survivorship.

RESULTS

The MCMI group, compared with the PMM one, showed significantly lower VAS for pain (1.2 ± 0.9 vs 3.3 ± 1.8; P = .004) and higher objective IKDC (7A and 10B for MCMI, 4B and 12C for PMM; P = .0001), Teger index (75 ± 27.5 vs 50 ± 11.67; P = .026), and SF-36 (53.9 ± 4.0 vs 44.1 ± 9.2; P = .026 for Physical Health Index; 54.7 ± 3.8 vs 43.8 ± 6.5; P = .004 for Mental Health Index) scores. Radiographic evaluation showed significantly less medial joint space narrowing in the MCMI group than in the PMM group (0.48 ± 0.63 mm vs 2.13 ± 0.79 mm; P = .0003). No significant differences between groups were reported regarding Lysholm (P = .062) and Yulish (P = .122) scores. Genovese score remained constant between 5 and 10 years after surgery (P = .5). The MRI evaluation of the MCMI patients revealed 11 cases of myxoid degeneration signal: 4 had a normal signal with reduced size, and 2 had no recognizable implant.

CONCLUSION

Pain, activity level, and radiological outcomes are significantly improved with use of the MCMI at a minimum 10-year follow-up compared with PMM alone. Randomized controlled trials on a larger population are necessary to confirm MCMI benefits at long term.

Is radiographic measurement of bony landmarks reliable for lateral meniscal sizing?

BACKGROUND

The accuracy of meniscal measurement methods is still in debate.

HYPOTHESIS

The authors' protocol for radiologic measurements will provide reproducible bony landmarks, and this measurement method of the lateral tibial plateau will correlate with the actual anatomic value.

STUDY DESIGN

Controlled laboratory study.

METHODS

Twenty-five samples of fresh lateral meniscus with attached proximal tibia were obtained during total knee arthroplasty. Each sample was obtained without damage to the meniscus and bony attachment sites. The inclusion criterion was mild to moderate osteoarthritis in patients with mechanical axis deviation of less than 15°. Knees with lateral compartment osteoarthritic change or injured or degenerated menisci were excluded. For the lateral tibial plateau length measurements, the radiographic beam was angled 10° caudally at neutral rotation, which allowed differentiation of the lateral plateau cortical margins from the medial plateau. The transition points were identified and used for length measurement. The values of length were then compared with the conventional Pollard method and the anatomic values. The width measurement was done according to Pollard's protocol. For each knee, the percentage deviation from the anatomic dimension was recorded. Intraobserver error and interobserver error were calculated.

RESULTS

The deviation of the authors' radiographic length measurements from anatomic dimensions was 1.4 ± 1.1 mm. The deviation of Pollard's radiographic length measurements was 4.1 ± 2.0 mm. With respect to accuracy-which represents the frequency of measurements that fall within 10% of measurements-the accuracy of authors' length was 98%, whereas for Pollard's method it was 40%. There was a good correlation between anatomic meniscal dimensions and each radiologic plateau dimensions for lateral meniscal width (R(2) = .790) and the authors' lateral meniscal length (R(2) = .823) and fair correlation for Pollard's lateral meniscal length (R(2) = .660). The reliability of each radiologic measurement showed good reliability (intraclass correlation coefficients, .823 to .973). The authors tried to determine the best-fit equation for predicting meniscal size from Pollard's method of bone size, as follows: anatomic length = 0.52 × plateau length (according to Pollard's method) + 5.2, not as Pollard suggested (0.7 × Pollard's plateau length). Based on this equation-namely, the modified Pollard method-the percentage difference decreased, and the accuracy increased to 92%.

CONCLUSION

Lateral meniscal length dimension can be accurately predicted from the authors' radiographic tibial plateau measurements.

CLINICAL RELEVANCE

This study may provide valuable information in preoperative sizing of lateral meniscus in meniscal allograft transplantation.

The "butterfly" suture technique for meniscal repair

One of the important factors effecting meniscal healing is the strength of primary fixation obtained by repairing technique. From this perspective, it is important to choose the technique ensuring a higher primary fixation strength for meniscal repairs. We described a new technique for meniscal repair called "butterfly" technique using Viper device and hypothesized that high primary fixation strength can be obtained with this technique. The study was performed on calve knees. Full-thickness longitudinal tears 2 cm in length and 3 mm medial from the periphery were created in corpora of medial menisci of 14 calves. After creating tears, menisci were divided into two equal groups. In Group 1, two vertical loop sutures 1 cm apart were placed using a Viper device. Whereas in Group 2, tears were repaired using "butterfly" sutures. The mean load to failure was 156.3 ± 13.1 and 186 ± 15.8 N in Group 1 and 2, respectively (p = 0.002). The fixation strength in Group 2 was significantly higher than in Group 1. We suggest that, using Viper device and all-inside "butterfly" suturing techniques, meniscal ruptures with appropriate locations can be repaired with higher primary fixation strength.

Arthroscopic all-inside meniscal repair--Does the meniscus heal? A clinical and radiological follow-up examination to verify meniscal healing using a 3-T MRI

OBJECTIVE

The purpose of this study was to correlate clinical and radiological results using a 3-T MRI to verify meniscal healing after arthroscopic all-inside meniscus repair.

MATERIALS AND METHODS

We selected 27 patients (14 men and 13 women) with an average age of 31 ± 9 years and retrospective clinical examinations and radiological assessments using a 3-T MRI after all-inside arthroscopic meniscal repair were conducted. Repair of the medial meniscus was performed in 19 patients and of the lateral meniscus in eight. In 17 patients (63%), we performed concomitant anterior cruciate ligament reconstruction. The mean follow-up period was 4.5 ± 1.7 years. The Lysholm score and Tegner activity index were used for clinical evaluation. Four grades were used to classify the radiological signal alterations within the meniscus: central globular (grade 1); linear horizontal or band-like (grade 2); intrameniscal alterations and linear signal alterations communicating with the articular surface (grade 3); and complex tears (grade 4).

RESULTS

At follow-up, the average Lysholm score was 76 ± 15 points, with ten of the patients placed in group 6 based on the Tegner activity index. MRI examinations revealed no signal alteration in three patients, grade 1 in 0, grade 2 in five, grade 3 in 13, and grade 4 in six. The MRI findings correlated positively with the clinical scores in 21 patients (78%).

CONCLUSIONS

Correlation of clinical and radiological examination was performed using 3-T MRI. In spite of satisfactory clinical outcomes at follow-up, a radiological signal alteration may still be visible on MRI, which was believed to be scar tissue, but could not be proven definitively. Imaging with a 3-Tesla MRI after meniscal suture surgery provides good but no definitive reliability on meniscus healing and therefore gives no advantage compared to 1.5-T MRI, with good clinical outcome using an all-inside arthroscopic meniscal repair.

CLINICAL RELEVANCE

3T-MRI can not substitute diagnostic arthroscopy in patients with persistent complaints after arthroscopic all-inside meniscal repair.

Practice patterns for combined anterior cruciate ligament and meniscal surgery in the United States

PURPOSE

The purpose of the study was to compare frequency of meniscal repair to partial meniscectomy in patients undergoing anterior cruciate ligament reconstruction using the American Board of Orthopaedic Surgeons (ABOS) database.

HYPOTHESES

(1) Practice patterns are similar with respect to geographic region. (2) Surgeons with fellowship training perform more meniscal repairs compared with general orthopaedic practitioners. (3) Younger patients are more likely to be treated with meniscal repair at the time of anterior cruciate ligament reconstruction. (4) The frequency of meniscal repair in conjunction with anterior cruciate ligament reconstruction has increased over time.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Information was extracted from the ABOS database from 2002 orthopaedic surgeons who sat for the part II examination from 2003 to 2007. The database was queried for all patients who underwent anterior cruciate ligament reconstruction (Current Procedural Terminology [CPT] code 29888) without or with meniscectomy (CPT 29881) or meniscal repair (CPT 29882). Factors affecting meniscal surgery that were investigated included patient age, geographic region of practice, fellowship training, and declared subspecialty of the surgeon.

RESULTS

On average there were 52,000 cases per year registered in the ABOS database, approximately 1700 of whom underwent anterior cruciate ligament reconstruction. Meniscal repair was most frequently performed in the Southwest region (18.6%, P < .001) and least frequently in the Northwest region (11.3%, P < .001). Combined anterior cruciate ligament reconstruction and meniscal repair was performed significantly more often by fellowship-trained surgeons (17%) than by surgeons with other fellowship training (12%) or no fellowship training (12%, P < .001) and in patients younger than age 25 years (19%) compared with those age 40 years and older (8%, P <.001). Meniscal repair was performed in 13.9% of anterior cruciate ligament reconstructions in 2003 and in 16.4% of anterior cruciate ligament reconstructions in 2007 (P > .05).

CONCLUSION

Combined anterior cruciate ligament reconstruction with meniscal repair was more frequent for younger patients and by surgeons with sports fellowship training. Concomitant meniscal repair is performed by fellowship-trained surgeons in this study in only 18% of anterior cruciate ligament reconstructions.

Biomechanical evaluation of arthroscopic all-inside meniscus repairs

Viper is a new device for arthroscopically all-inside meniscal repairing. In previous studies about Viper device, procedures were not applied arthroscopically despite this device has been designed for arthroscopic application. In this study, we evaluated primary fixation strength of arthroscopically applied meniscal repair using Viper device to obtain better clinical relevance. Two centimeter in length meniscal tear 2-3 mm far from periferic edge of medial meniscus of 50 calves were created arthroscopically. The menisci were divided into five groups including 10 menisci in each. In group 1, tears were repaired by outside-in vertical loop suture technique with No: 0 PDS. Tears were fixed by all-inside vertical suture by using Viper device with No: 0 PDS in group 2. In meniscal implant groups, RapidLoc, H-Fix, and Clearfix were applied in groups 3,4, and 5, respectively. Primary fixation strength of repairing techniques were evaluated with bio-mechanical testing machine. Fixation strengths determined in groups 1 and 2 were detected as 145 +/- 13 and 136 +/- 33 N, respectively. There was no difference in pull-out strength between groups 1 and 2. Fixation strengths in these two groups were significantly higher compared to groups 3, 4, and 5. There was no significant difference between group 3 (33 +/- 6 N) and 5 (28 +/- 6 N) in terms of fixation strengths whereas fixation strengths of these two groups were significantly higher compared to group 4 (20 +/- 3 N) (P = 0.005, P = 0.018, respectively). All-inside vertical suture technique using Viper device revealed comparable primary fixation strength with outside-in vertical suture technique for meniscal repair. We suggest that the Viper device is safe and reliable for meniscal repair.

THE ROLE OF FIBRIN GLUE AND SUTURE ON THE FIXATION OF ULTRA FROZEN PRESERVED MENISCUS TRANSPLANTATION IN RABBITS

Objective: To evaluate the ability of fibrin adhesive in promoting the meniscus fixation within two, four and eight weeks compared to the conventional soft-tissue suture technique. Materials and Methods: 36 right medial menisci of rabbits preserved at negative 73° Celsius for 30 days were transplanted to animals of the same sample and fixed with soft-tissue suture or fibrin glue. After 2, 4 or 8 weeks, the appearance of the menisci and the quality of fixation were macroscopically checked and evaluated by a scoring system. The findings were subjected to the statistical study of variance analysis (p ≤ 0.05%). Results: The deep-frozen meniscus preservation maintained the integrity of the meniscus transplant, and, macroscopically, there was no significant reduction of the length of the meniscus in all post-transplant periods (p = 0.015). The menisci fixed with fibrin showed slight changes in color and surface roughness. There were no signs of rejection or infection in both groups. Suture fixation scoring was superior (p = 0.015) in all periods (80% of total fixation) as compared to the setting promoted by fibrin (20% of total fixation). Conclusion: The homologous transplantation of the meniscus of rabbits experienced various degrees of integration to the knee according to the fixation method; the surgical soft tissues suturing technique was shown to be superior in the evaluation of scores compared to the fixation with fibrin adhesive.

FasT-Fix meniscal repair: mid-term results

PURPOSE

The purpose of this study was to evaluate the clinical success of the FasT-Fix meniscal repair device (Smith & Nephew Endoscopy, Andover, MA) associated with an accelerated rehabilitation program.

METHODS

A prospectively collected consecutive series of meniscal repairs performed with the FasT-Fix device was studied. The Lysholm, Tegner, Cincinnati, and International Knee Documentation Committee activity scores, along with the clinical examination findings and adverse events, were recorded for all patients. Associated procedures were recorded. An accelerated postoperative rehabilitation program was followed, independent of concurrent anterior cruciate ligament surgery.

RESULTS

Forty-one meniscal repairs were performed, with an average follow-up of 30.7 months (range, 12 to 58 months). Twenty-nine of 41 repairs were performed in conjunction with anterior cruciate ligment reconstruction. The other repairs were in stable knees. There were 26 medial and 15 lateral meniscus repairs. Both menisci were repaired in 5 knees. Repeat arthroscopies were performed for 12 repairs and 7 (17%) were found to have failed. The preoperative and postoperative Lysholm, Tegner, Cincinnati, and International Knee Documentation Committee activity scores were 47.3 and 87.4, 3.4 and 7.2, 38.7 and 82.8, and 2.3 and 3.4, respectively.

CONCLUSIONS

The FasT-Fix meniscal repair associated with an accelerated rehabilitation program resulted in clinically effective meniscal repair in 83% at the time of follow-up. Clinical outcome measures all improved.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

MR imaging of the meniscus: review, current trends, and clinical implications

MR imaging is the preferred imaging modality for evaluating the meniscus. Overall, when strict criteria are followed, it is accurate in diagnosing meniscal tears in patients who have not had prior meniscal surgery. However, an accurate interpretation requires a through knowledge of the normal meniscal anatomy, common meniscal variants, and common diagnostic pitfalls. In this article, the author emphasizes the importance of describing meniscal tears properly and discusses treatment options. Diagnosing a recurrent tear is more complicated in patients who have had prior partial meniscal resection or repair, and the use of MR arthrography in this group of patients is discussed. Recent developments in areas such as 3 T and parallel imaging offer promise for accurate meniscal evaluation with even shorter scan times.

Meniscal repair techniques

The human meniscus is important for normal knee function and distributes loads, aids in joint lubrication, congruence, stability, and proprioception. Repair of appropriate meniscal tears is possible and several methods exist to accomplish this including suture repairs and device repairs. Clinical evidence suggests that meniscal repairs can result in acceptable healing rates although adverse events have been reported for some devices. New self-adjusting suture devices have facilitated the accurate and effective repair of the torn meniscus. Technique descriptions for these devices are presented.

Multiple freeze-thaw cycled meniscal allograft tissue: A biomechanical, biochemical, and histologic analysis

Meniscus allografting has provided relief of meniscal injuries that were previously thought irreparable. However, meniscus allograft tissue remains limited and a significant problem. To improve allograft tissue yield, decrease processing costs, and increase graft availability, this study investigated the biomechanical changes of meniscal allograft tissue frozen and thawed multiple times. Specifically, our study compared the intrinsic compressive resistances of meniscus undergoing four Freeze-Thaw cycles versus tissue undergoing a single Freeze-Thaw cycle. Seven menisci that were originally procured and processed for allografting were donated for the study. Each meniscus was segmented and samples independently underwent novel constant slow-rate compression testing, and histological and biochemical evaluation. The menisci that underwent a single Freeze-Thaw cycle demonstrated a significantly higher Young's Modulus (14 megapascals) as compared to menisci undergoing multiple Freeze-Thaw cycles (10 megapascals, p = 0.03). These results were maintained when medial and lateral menisci were compared independently. Histological and biochemical analyses supported, but did not provide an explanation for the change in intrinsic compressive resistance. From these results, transplantation of meniscal allograft tissue frozen and thawed four times may be compromised in its ability to resist compression; and thus may undermine its role in replacing native meniscal tissue.

Meniscal Allografts: Biomechanics and Techniques

Arthroscopic partial meniscectomy is one of the most common orthopedic surgical procedures performed. Numerous clinical and biomechanical studies have shown the long-term consequences of the meniscus-deficient knee, which includes increased loading of the cartilage. This leads to chondromalacia, and ultimately pain and dysfunction. Few treatment options are available for the young patient with pain in the tibiofemoral compartment secondary to meniscus deficiency. Meniscal allograft transplantation is a viable treatment option in this group of patients as short-term results have shown pain relief and functional improvement. Biomechanical studies have shown that the allograft meniscal transplant functions most like a native, intact meniscus when specific surgical principles are followed. Surgical techniques for meniscal allograft transplantation have advanced along with instrumentation. An improvement in function and pain relief can be expected when strict criteria are followed in patient selection and surgical technique.

Reliability, validity, and responsiveness of the IKDC score for meniscus injuries of the knee

PURPOSE

The purpose of this study was to determine the psychometric properties of the International Knee Documentation Committee (IKDC) score for meniscus injuries of the knee.

METHODS

Test-retest reliability, content validity, construct validity, and responsiveness to change were determined for the IKDC score. Knees were excluded if they had ligament pathology or a chondral defect greater than Outerbridge grade 2. All patients had meniscus pathology requiring treatment. The study comprised 4 subsets of patients. Group A consisted of 31 patients who completed an IKDC form at least 2 years after surgery for meniscus pathology and were then retested within 4 weeks of the primary questionnaire. Group B contained 264 patients with preoperative IKDC scores that were used for construct and content validity. Group C contained 50 patients who had a preoperative IKDC score and completed a short form 12 survey. Group D contained 100 patients with preoperative and postoperative IKDC scores used to measure responsiveness.

RESULTS

The overall IKDC score showed acceptable test-retest reliability with an interclass correlation of 0.95. There were acceptable floor and ceiling effects. All constructs tested showed significant differences. These included lower IKDC score with the following: lower activity level, difficulty with activities of daily living, difficulty with sports, abnormal knee function, and complex/degenerative meniscus tears. Responsiveness to change showed a large effect size (2.11) and a large response mean (1.5) for the overall score. The SE of the measurement was 3.19, and the minimum detectable change was 8.8 points.

CONCLUSIONS

The overall IKDC score showed overall acceptable psychometric performance for outcome measures of meniscus injuries of the knee.

LEVEL OF EVIDENCE

Level III, testing of previously developed diagnostic criteria in nonconsecutive patients.

Meniscal sizing based on gender, height, and weight

PURPOSE

Successful meniscus transplantation may depend on accurate sizing. Meniscal sizing is currently determined by measuring a combination of bony landmarks and soft-tissue insertion points through images obtained radiographically or by magnetic resonance imaging (MRI). The literature widely reports inaccuracy in sizing resulting from radiographic errors in magnification, erroneous identification of bony landmarks, and difficulty in differentiating between the soft-tissue and bone interface. In our meniscus transplantations we have observed that when the height and weight of the recipient matched those of the donor, the meniscal size appeared to be a match at surgical implantation; we designed this study to confirm this observation.

METHODS

The MRI-based meniscal sizing of 111 patients (63 male and 38 female patients; mean age, 44 years [range, 15 to 76 years]), totaling 147 menisci (87 lateral and 60 medial), was compared with the height, weight, gender, and body mass index (BMI) of each patient. MRI scans were obtained with a 1.0-Tesla MRI system (ONI Medical Systems, Wilmington, MA). Sizing was performed by an independent musculoskeletal MRI radiologist as established by the literature. Statistical methods include nonparametric Pearson correlation (r) between MRI-based lateral meniscal width, lateral meniscal length, medial meniscal width, medial meniscal length, total tibial plateau width, and patient height, weight, gender, and BMI. Significance at the P = .05 level was used.

RESULTS

Height was found to have a linear relationship to total tibial plateau, which has a good predictive correlation with meniscal dimensions of r > 0.7. Female patients generally present with smaller dimensions than male patients. High-BMI groups present with significantly larger meniscal dimensions than low-BMI groups at any given height.

CONCLUSIONS

Height, weight, and gender are easily obtained variables and are proportional to meniscal tissue dimensions. These exploratory statistics establish correlations between height, weight, gender, total tibial plateau width, and meniscal size.

CLINICAL RELEVANCE

Height, weight, and gender should be considered by both tissue banks and surgeons as fast and cost-effective variables by which to predict meniscal dimensions.

MR Imaging of the Meniscus: Review, Current Trends, and Clinical Implications

MR imaging is the preferred imaging modality for evaluating the meniscus. Overall, when strict criteria are followed, it is accurate in diagnosing meniscal tears in patients who have not had prior meniscal surgery. However, an accurate interpretation requires a through knowledge of the normal meniscal anatomy, common meniscal variants, and common diagnostic pitfalls. In this article, the author emphasizes the importance of describing meniscal tears properly and discusses treatment options. Diagnosing a recurrent tear is more complicated in patients who have had prior partial meniscal resection or repair, and the use of MR arthrography in this group of patients is discussed. Recent developments in areas such as 3 T and parallel imaging offer promise for accurate meniscal evaluation with even shorter scan times.

Biomedical devices in meniscal repair

Preservation of the menisci is increasingly emphasized in orthopedic care of the knee. Techniques are rapidly emerging that allow easier accomplishment of this goal. In particular, the development of all-inside arthroscopic meniscal repair devices has facilitated more ready repair. A number of laboratory and clinical studies have examined these devices and comparisons with more traditional techniques have been made. Numerous reports of potential complications from these new technologies have also been described in the literature. This review covers the current options for treatment of meniscal repair, laboratory and clinical data, and also potential complications.

Pullout strength of meniscal repair after cyclic loading: comparison of vertical, horizontal, and oblique suture techniques

This in vitro biomechanical study with cyclic loading compared the pullout strength of vertical, horizontal, and oblique sutures used for meniscal lesion repair. Following repair of vertical longitudinal lesions created in bovine medial menisci, three groups of seven specimens (vertical, horizontal, and oblique sutures) underwent cyclic loading in a randomized test order (5 mm/min, cycling between 5 and 50 N at 1 Hz for 100 cycles) prior to load to failure testing (5 mm/min). Displacement did not differ between groups during cyclic or load to failure testing. Construct stiffness during cyclic testing was superior for the oblique suture (6.9 +/- 1.5 N/mm, P = 0.007) and the vertical suture (6.4 +/- 7 N/mm, P = 0.03) groups compared to the horizontal suture group (4.4 +/- 0.52 N/mm). The oblique suture (171.9 +/- 25.9 N, P < 0.0001) and the vertical suture (145.9 +/- 32.3 N, P = 0.001) groups displayed superior load at failure compared to the horizontal suture group (88.8 +/- 8.2 N). Construct stiffness during load to failure testing did not differ between groups. Suture rupture was the failure mode for all specimens of the oblique suture group. Suture rupture was the failure mode for 57% (4/7) of the vertical suture group with the remaining specimens (3/7, 43%) failing from intact suture pullout through meniscal tissue. All horizontal suture group specimens failed by intact suture pulling through meniscal tissue. With comparable stiffness during cyclic testing, comparable load at failure as vertical sutures, and less evidence of intact suture pullout through the meniscus, an oblique suture technique may combine the beneficial characteristics of vertical (superior biomechanical strength) and horizontal (ease of application, longer sutures with a tendency to cover a larger meniscal tissue area) suture-repair techniques.