Innate Immune Response Analysis in Meniscus Xenotransplantation Using Normal and Triple Knockout Jeju Native Pigs.

Although allogenic meniscus grafting can be immunologically safe, it causes immune rejection due to an imbalanced tissue supply between donor and recipient. Pigs are anatomically and physiologically similar to adult humans and are, therefore, considered to be advantageous xenotransplantation models. However, immune rejection caused by genetic difference damages the donor tissue and can sometimes cause sudden death. Immune rejection is caused by genes; porcine GGTA1, CMAH, and B4GLANT2 are the most common. In this study, we evaluated immune cells infiltrating the pig meniscus transplanted subcutaneously into BALB/c mice bred for three weeks. We compared the biocompatibility of normal Jeju native black pig (JNP) meniscus with that of triple knockout (TKO) JNP meniscus (α-gal epitope, N-glycolylneuraminic acid (Neu5Gc), and Sd (a) epitope knockout using CRISPR-Cas 9). Mast cells, eosinophils, neutrophils, and macrophages were found to have infiltrated the transplant boundary in the sham (without transplantation), normal (normal JNP), and test (TKO JNP) samples after immunohistochemical analysis. When compared to normal and sham groups, TKO was lower. Cytokine levels did not differ significantly between normal and test groups. Because chronic rejection can occur after meniscus transplantation associated with immune cell infiltration, we propose studies with multiple genetic editing to prevent immune rejection.

Return to Work Following Arthroscopic Meniscal Allograft Transplantation.

PURPOSE: Evaluate the ability of patients to return to work (RTW) following arthroscopic meniscal allograft transplantation (MAT) for meniscal deficiency. METHODS: Consecutive patients undergoing MAT were retrospectively reviewed at a minimum of 2 years postoperatively. Patients completed a subjective work questionnaire, Visual Analogue Scale for pain, Single Assessment Numerical Evaluation, and satisfaction. RESULTS: Forty-seven patients who were employed within 3 years prior to surgery (average age: 30.2 ± 6.9 years) were contacted at an average of 3.5 ± 0.9 years postoperatively. Forty-six patients (97.8%) returned to work by 2.7 ± 2.6 months postoperatively, and 44 patients (93.6%) returned to the same level of occupational intensity. Patients who held sedentary, light, medium, or high intensity occupations were able to RTW at a rate of 100.0%, 100.0%, 88.9%, and 85.7% (P = 0.4) by 1.1 ± 1.0 months, 2.5 ± 2.5 months, 3.5 ± 3.2 months, and 4.3 ± 2.8 months (P = 0.3) postoperatively. Thirty-eight patients (80.9%) were at least somewhat satisfied, and 43 patients (91.5%) would still have the operation if presented the opportunity. No patient underwent revision MAT or conversion to arthroplasty. CONCLUSION: In patients with painful meniscal deficiency, MAT provides a high rate of RTW (97.8%) by 2.7 ± 2.6 months postoperatively. However, some patients may be unable to return to their previous level of occupational intensity. Although statistically insignificant, patients with higher intensity occupations may have a lower rate and longer duration until RTW than those with less physically demanding occupations. Information regarding RTW is imperative for appropriately managing postoperative expectations.

Unicompartmental bipolar osteochondral and meniscal allograft transplantation is effective for treatment of medial compartment gonarthrosis in a canine model.

Osteochondral allograft (OCA) transplantation can restore large articular defects in the knee. Bipolar OCA transplantations for partial and whole joint resurfacing often have less favorable results than single-surface transplants. This study was designed to use a large animal model to test the hypothesis that unicompartmental bipolar osteochondral and meniscal allograft transplantation (BioJoint) would be as or more effective for treatment of medial compartment osteoarthritis (OA) compared to standard-of-care nonoperative treatment. OA was induced in one knee of each research hound (n = 8) using a meniscal release model and pretreatment assessments were performed. After 3 months, dogs were randomly assigned to either the control group (n = 4, no surgical intervention, daily nonsteroidal antiinflammatory drugs [NSAIDs]) or the BioJoint group (n = 4). Clinical, radiographic, and arthroscopic assessments were performed longitudinally and histopathology was evaluated at the 6-month endpoint. At study endpoint, functional, pain, and total pressure index measures, as well as radiographic and arthroscopic grading of graft appearance and joint health, demonstrated superior outcomes for BioJoints compared to NSAID controls. Furthermore, histologic assessments showed that osteochondral and meniscal transplants maintain integrity and integrated into host tissues. Clinical significance: The results support the safety and efficacy of unicompartmental bipolar osteochondral and meniscal allograft transplantation in a preclinical model with highly functional outcomes without early OA progression.

Staged meniscal allograft transplantation as a biologic treatment of the meniscal deficient knee: A prospective case series of 26 patients with maximum 88-month follow-up.

INTRODUCTION: The meniscal deficient knee often exists within the setting of associated pathology including instability, malalignment and chondral injury. The aim of this study was to establish the role of meniscal allograft transplantation (MAT) as part of a staged approach to treatment of the previously menisectomised knee and report: (a) primary data endpoints (pre and post-operative Knee Injury and Osteoarthritis outcome scores (KOOS), Tegner scores, satisfaction scores and graft survival), and (b) secondary endpoints:(complication/reoperation rates, and meniscal extrusion measurements as determined by MRI). MATERIAL AND METHODS: This prospective study included all patients that underwent arthroscopic fresh frozen allograft MAT at our institution (2010-2017) using a soft tissue fixation technique. RESULTS: Twenty-seven MAT procedures were performed in 26 patients (16 lateral, 11 medial). Ten patients underwent ACL reconstruction, three ACI and two osteotomy in the pre-MAT phase. Seven patients underwent ACI within the post-operative phase. Post-operative mean KOOS scores improved significantly in all subscales (p < .002) as did Tegner scores (p < .05). Graft survival was 100%, satisfaction rate 92%, and mean meniscal extrusion 3.04 mm. Post operatively, three patients required meniscal repair and a single patient, partial menisectomy of graft. Two patients underwent arthroscopic arthrolysis following MAT. CONCLUSIONS: This series highlights the multifactorial profile of the meniscal deficient knee and the role of MAT as a safe and reliable technique in the staged and comprehensive biologic treatment available to minimise symptoms and maximise outcomes. LEVEL OF EVIDENCE: 4.

[Indications and results of meniscal transplantation]. / Indications et résultats de la transplantation méniscale.

Meniscectomy in a young active patient can lead to poor outcomes with pain, decreased function and long-term osteoarthritis. Meniscal allograft transplantation (MAT) has therefore been developed to address this issue. We now have 30 years of experience with this technique which is no longer considered experimental and new indications have been added. MAT allows restoration of joint biomechanics, pain relief, improvement in knee function and stability, and reduce cartilage degeneration. This is a comprehensive review of the role of menisci, the indications and principles of MAT, as well as these results.

La méniscectomie chez un jeune patient actif peut mener à de mauvais résultats avec des douleurs, une diminution de la fonction puis de l'arthrose à long terme. La transplantation d'allogreffe méniscale (TAM) a donc été développée pour répondre à cette problématique. Nous avons maintenant 30 ans de recul sur cette technique, elle n'est plus considérée comme expérimentale et de nouvelles indications ont été ajoutées. La TAM permet de restaurer la biomécanique du genou et donc de soulager les douleurs, d'améliorer la fonction et la stabilité du genou ainsi que de ralentir la dégénérescence cartilagineuse. Cet article fait le point sur le rôle des ménisques, les indications et principes de la TAM ainsi que ses résultats.

Reoperation Rates Following Meniscus Transplantation Using the Truven Database.

PURPOSE: The purpose of this study was to determine the (1) reoperation rate and (2) 30-day complication rate in a large insurance database. METHODS: The Truven Database was queried for subjects that underwent meniscus allograft transplantation (Current Procedural Terminology code 29868) in the outpatient setting with minimal 2-year follow-up. Patients without confirmed laterality and patients that underwent concomitant ligament reconstruction were excluded. Reoperation was defined by ipsilateral knee procedure after the index surgery. The 30-day postoperative complication rates were assessed using International Classification of Diseases, 9th Revision, Clinical Modification codes. RESULTS: A total of 284 patients (mean age of 26.2 ± 10.4 years; 49.6% females) were included in this study with mean follow up of 43.2 ± 19.2 months. One hundred and sixty-seven subjects (58.8%) undergoing meniscus allograft transplantation underwent reoperation at an average of 11.9 ± 12.2 months postoperatively. There was a low number of subjects that required ipsilateral unicompartmental knee arthroplasty and total knee arthroplasty postoperatively (0.7% and 1.1%, respectively). The overall 30-day complication rate following meniscus allograft transplantation was 1.4%. CONCLUSIONS: Patients undergoing meniscus allograft transplantation have a 58.8% reoperation rate at final follow up with low (1.4%) 30-day complication rates in a large insurance database. LEVEL OF EVIDENCE: Level IV, case series.

Meniscal Allograft Transplantation After Anterior Cruciate Ligament Reconstruction Can Improve Knee Stability: A Comparison of Medial and Lateral Procedures.

BACKGROUND: The purpose of this study was to evaluate the clinical score and stability after meniscal allograft transplantation (MAT) after a previous anterior cruciate ligament (ACL) reconstruction. HYPOTHESIS: Medial MAT would improve anteroposterior stability, and lateral MAT would improve rotational stability. STUDY DESIGN: Cohort study; Level of evidence, 3. METHOD: We retrospectively investigated 31 cases of MAT after a previous total or nearly total meniscectomy and ACL reconstruction between November 2008 and June 2017. Cases were divided into medial (16 cases) and lateral (15 cases) MAT groups. The patients were assessed preoperatively and at the 2-year follow-up. RESULTS: In the medial MAT group, the International Knee Documentation Committee, Lysholm, Lysholm instability, and Tegner scores improved significantly at the 2-year follow-up, and there were also significant improvements in the anterior drawer, Lachman, and pivot-shift tests. In the lateral MAT group, the Lysholm and Tegner scores improved significantly at the 2-year follow-up, as had the anterior drawer and Lachman tests but not the pivot-shift test. The medial MAT group showed significant improvement in side-to-side difference on Telos stress radiographs, from 6.5 mm (preoperatively) to 3.6 mm (2-year follow-up) (P = .001), while the lateral MAT group showed no significant change. There was no progression of arthritis in either group. CONCLUSION: Medial MAT improved not only anteroposterior stability but also rotational stability in the meniscus-deficient ACL-reconstructed knee. Lateral MAT showed improvements in the anterior drawer and Lachman tests but not in the pivot-shift test or side-to-side difference on Telos stress radiographs in meniscus-deficient ACL-reconstructed knees. Instability and pain are indications for MAT in meniscus-deficient ACL-reconstructed knees.

Entrapped in cage (EiC) scaffolds of 3D-printed polycaprolactone and porous silk fibroin for meniscus tissue engineering.

The meniscus has critical functions in the knee joint kinematics and homeostasis. Injuries of the meniscus are frequent, and the lack of a functional meniscus between the femur and tibial plateau can cause articular cartilage degeneration leading to osteoarthritis development and progression. Regeneration of meniscus tissue has outstanding challenges to be addressed. In the current study, novel Entrapped in cage (EiC) scaffolds of 3D-printed polycaprolactone (PCL) and porous silk fibroin were proposed for meniscus tissue engineering. As confirmed by micro-structural analysis the entrapment of silk fibroin was successful, and all scaffolds had excellent interconnectivity (≥99%). The EiC scaffolds had more favorable micro-structure compared with the PCL cage scaffolds by improving the pore size while keeping the interconnectivity almost the same. When compared with the PCL cage, the entrapment of porous silk fibroin into the PCL cage decreased the high compressive modulus in a favorable matter in the wet state thanks to the silk fibroin's high swelling properties. The in vitro studies with human stem cells or meniscocytes seeded constructs, demonstrated that the EiC scaffolds had superior cell adhesion, metabolic activity, and proliferation compared to the PCL cage scaffolds. Upon subcutaneous implantation of scaffolds in nude mice, all groups were free of adverse incidents, and mildly invaded by inflammatory cells with neovascularization, while the EiC scaffolds showed better tissue infiltration. The results of this work indicated that the EiC scaffolds of PCL and silk fibroin are favorable for meniscus tissue engineering, and the findings are encouraging for further studies using a larger animal model.

Morphometric measurements to predict meniscal size in skeletally mature dogs for meniscal transplantation.

OBJECTIVE: To determine a relationship between morphometric measurements (MM) and meniscal dimensions (MD) in the dog. STUDY DESIGN: Cadaveric study. ANIMALS: Eighteen mixed-breed canine cadavers (22.35 ± 4.06 kg); 36 each of medial and lateral menisci. METHODS: The following MM were obtained in duplicate: height at scapula, withers, pelvis, rump, and greater trochanter; chest circumference; pelvic circumference; length from occiput to the base of the tail; hock to stifle length (HS); body weight; body condition score; and body fat percentage (BF%). Stifles were disarticulated, and digital photographs of in situ menisci were used to obtain meniscal measurements in duplicate. Morphometric parameters were compared with MD via Pearson correlation (r). A correlation of r ≥ 0.65 was considered strong. RESULTS: The strongest correlation was noted between HS and MD, with r = 0.85 for lateral meniscal width, r = 0.77 for medial meniscal length, and r = 0.76 for medial meniscal width. Lateral meniscal length had the strongest correlation with height at rump (HRu) (r = 0.73). Body weight correlated strongly with meniscal width and fairly with meniscal length. Body condition score and BF% correlated weakly with MD. CONCLUSION: Hock to stifle length was an easily obtainable variable and was proportional to MD. CLINICAL SIGNIFICANCE: Hock to stifle length may be considered by tissue banks and veterinary surgeons as a quick and cost effective screening tool for appropriate meniscal sizing in dogs.

Meniscus-shaped cell-free polyglycolic acid scaffold for meniscal repair in a sheep model.

Since loss of meniscus is correlated with an increasing risk for osteoarthritis, meniscal scaffolds are proposed as new strategies. Development of a suitable scaffold has to take into account differing meniscus thickness, exposure to compressive and tensile forces combined with high porosity and biocompatibility of the material. After physical testing of three flat scaffolds composed of different modified polyglycolic acid (PGA) fibers, a three-dimensional meniscus-shaped PGA-hyaluronan implant was generated. Micro-computed tomography showed 90% porosity in the outer area with 50% in the inner area of the implant. Biocompatibility and expression of meniscus typical cartilaginous genes were shown for human meniscus cells cultivated in the implant with 10% human serum or 5% platelet-rich plasma for 14 days in vitro. The proof-of-concept study in sheep demonstrated proteoglycan- and collagen type I-rich repair tissue formation in partial meniscectomy combined with a meniscus-shaped PGA-hyaluronan implant after 6 months. In contrast, the control showed nearly no repair tissue formation. Thus, meniscus-shaped PGA-hyaluronan implants might be a suitable therapeutic approach to support repair tissue formation in partial meniscectomy.

Clinical outcomes and survival rate of autologous chondrocyte implantation with and without concomitant meniscus allograft transplantation: 10- to 15-year follow-up study.

PURPOSE: The purpose of this study was to compare the clinical outcomes and survival rate of autologous chondrocyte implantation (ACI) with or without concomitant meniscus allograft transplantation (MAT). METHODS: Patients who underwent ACI of the medial or lateral femoral condyle with or without concomitant MAT were retrospectively reviewed. There were 14 patients (mean age, 31.2 ± 9.9 years) who underwent isolated ACI and 19 patients who underwent ACI with concomitant MAT (mean age, 34.8 ± 8.4 years). The International Knee Documentation Committee (IKDC) subjective score, Lysholm score, Tegner activity score, and 10- to 15-year survival rate were compared between groups. RESULTS: All clinical scores showed significant improvement postoperatively in both groups. At final follow-up, the IKDC subjective score was superior in isolated ACI (75.8 ± 18.4) compared to ACI with MAT (61.0 ± 16.6, p = 0.024). The Lysholm score was also higher in isolated ACI (77.5 ± 19.1) than ACI with MAT (62.5 ± 18.1, p = 0.029). The Tegner activity score did not differ between treatments (isolated ACI, 5.3 ± 1.1; ACI with MAT, 4.5 ± 1.3; p = 0.072). The 15-year survival rate for isolated ACI was higher than that of ACI with concomitant MAT (69.6% vs 50.2%), but this difference was not statistically significant (p = 0.19). CONCLUSIONS: ACI with concomitant MAT did not restore clinical outcomes as much as isolated ACI. There was a trend for the long-term survival rate to be greater in isolated ACI than ACI with MAT. These results should be considered in planning for the treatment of focal chondral defect with meniscus deficiency. LEVEL OF STUDY: Retrospective comparative trial; level of evidence, 3.

The 50 Most-Cited Articles in Meniscal Allograft Transplantation Research: A Bibliometric Analysis.

OBJECTIVE: To identify the 50 most-cited articles in meniscal allograft transplantation (MAT) research and analyze their characteristics. DESIGN: In September 2017, the Scopus database was queried to identify the 50 most-cited articles in MAT research. Variables analyzed include number of citations, publication year, journal, institution, country of origin, article type, study design, and level of evidence. Citation density was calculated for each article. The correlation between citation density and publication year and the correlation between level of evidence and number of citations, citation density, and publication year were computed. RESULTS: The 50 most-cited articles were published in 12 journals between 1986 and 2011. The number of citations ranged from 59 to 290 (109.3 ± 48.6). Citation density ranged from 2.7 to 17.6 citations per year (7.0 ± 3.3). There was a positive correlation between citation density and publication year ( r = +0.489, P < 0.001). Overall, 56% of the articles were clinical and 44% were basic science. Of the 28 clinical articles, 61% were level IV or V evidence. Level of evidence was not significantly correlated with number of citations ( r = -0.059, P = 0.766), citation density ( r = +0.030, P = 0.880), or publication year ( r = -0.0009, P = 0.996). CONCLUSION: This analysis provides the orthopedic community with a readily accessible list of the classic citations in MAT research and provides insight into the historical development of this procedure. Although there was a moderate positive correlation between citation density and publication year, articles with stronger levels of evidence were not more frequently cited despite the increasing trend toward evidence-based practice.

Cells, soluble factors and matrix harmonically play the concert of allograft integration.

Implantation of allograft tissues has massively grown over the last years, especially in the fields related to sports medicine. Beside the fact that often no autograft option exists, autograft related disadvantages as donor-site morbidity and prolonged operative time are drastically reduced with allograft tissues. Despite the well documented clinical success for bone allograft procedures, advances in tissue engineering raised the interest in meniscus, osteochondral and ligament/tendon allografts. Notably, their overall success rates are constantly higher than 80%, making them a valuable treatment option in orthopaedics, especially in knee surgery. Complications reported for allografting procedures are a small risk of disease transmission, immunologic rejection, and decreased biologic incorporation together with nonunion at the graft-host juncture and, rarely, massive allograft resorption. Although allografting is a successful procedure, improved techniques and biological knowledge to limit these pitfalls and maximize graft incorporation are needed. A basic understanding of the biologic processes that affect the donor-host interactions and eventual incorporation and remodelling of various allograft tissues is a fundamental prerequisite for their successful clinical use. Further, the importance of the interaction of immunologic factors with the biologic processes involved in allograft incorporation has yet to be fully dissected. Finally, new tissue engineering techniques and use of adjunctive growth factors, cell based and focused gene therapies may improve the quality and uniformity of clinical outcomes. The aim of this review is to shed light on the biology of meniscus, osteochondral and ligament/tendon allograft incorporation and how collection and storage techniques may affect graft stability and embodiment.Level of evidence V.

The Radiated Deep-frozen Xenogenic Meniscal Tissue Regenerated the Total Meniscus with Chondroprotection.

Meniscal allograft transplantation yields good and excellent results but is limited by donor availability. The purpose of the study was to evaluate the effectiveness of radiated deep-frozen xenogenic meniscal tissue (RDF-X) as an alternative graft choice in meniscal transplantation. The xenogenic meniscal tissues were harvested from the inner 1/3 part of the porcine meniscus and then irradiated and deeply frozen. The medial menisci of rabbits were replaced by the RDF-X. Meniscal allograft transplantation, meniscectomy and sham operation served as controls. Only a particular kind of rabbit-anti-pig antibody (molecular ranging 60-80 kD) was detected in the blood serum at week 2. The menisci of the group RDF-X grossly resembled the native tissue and the allograft meniscus with fibrocartilage regeneration at postoperative 1 year. Cell incorporation and the extracellular matrix were mostly observed at the surface and the inner 1/3 part of the newly regenerated RDF-X, which was different from the allograft. The biomechanical properties of the group RDF-X were also approximate to those of the native meniscus except for the compressive creep. In addition, chondroprotection was achieved after the RDF-X transplantation although the joint degeneration was not completely prevented. To conclude, the RDF-X could be a promising alternative for meniscal transplantation with similar tissue regeneration capacity to allograft transplantation and superior chondroprotection. The potential minor immunological rejection should be further studied before its clinical application.

Clinical and radiologic outcomes after a modified bone plug technique with anatomical meniscal root reinsertion for meniscal allograft transplantation and a minimum 18-month follow-up.

OBJECTIVE: To evaluate the clinical and radiologic outcomes of meniscal allograft transplantation (MAT) using a modified bone plug technique. METHODS: We conducted a retrospective single-center study of 73 patients who underwent MAT between January 2007 and December 2013. The International Knee Documentation Committee (IKDC) score, Lysholm score, Tegner score, visual analogue scale (VAS), and physical examinations were retrospectively reviewed to measure clinical outcomes after MAT, and questionnaires regarding activity and factors were analyzed. Magnetic resonance imaging (MRI) was used to assess the cartilage status and meniscal extrusion. RESULTS: The mean follow-up was 37 months for 61 patients (65 knees), and 12 patients were lost to follow-up. The mean meniscal extrusion was 3.39 ± 0.90 mm, the relative percentage of extrusion (RPE) was 34.82% ± 12.71%, and arthrosis progression was observed in 8 of 61 cases (13.1%). The mean results for VAS, IKDC, and Lysholm scores were significantly improved after MAT (P < 0.05), but there were no significant differences in the range of motion or Tegner score (P > 0.05). Thirty-eight (62.3%) patients were able to return to their previous level of activity, and 23 (37.7%) patients reached a mean 76.7% of the previous level of activity. Of the 23 patients reporting a decrease in activity, 10 reported a fear of reinjury as the primary factor limiting activity. The patient satisfaction rate in the study was 78.7%. CONCLUSION: Our modified bone plug method with anatomical meniscal root reinsertion was an effective surgical method, and the majority of active patients with meniscal disorders returned to preinjury levels of activity.

Native tissue-based strategies for meniscus repair and regeneration.

Meniscus injuries appear to be becoming increasingly common and pose a challenge for orthopedic surgeons. However, there is no curative approach for dealing with defects in the inner meniscus region due to its avascular nature. Numerous strategies have been applied to regenerate and repair meniscus defects and native tissue-based strategies have received much attention. Native tissue usually has good biocompatibility, excellent mechanical properties and a suitable microenvironment for cellular growth, adhesion, redifferentiation, extracellular matrix deposition and remodeling. Classically, native tissue-based strategies for meniscus repair and regeneration are divided into autogenous and heterogeneous tissue transplantation. Autogenous tissue transplantation is performed more widely than heterogeneous tissue transplantation because there is no immunological rejection and the success rates are higher. This review first discusses the native meniscus structure and function and then focuses on the use of the autogenous tissue for meniscus repair and regeneration. Finally, it summarizes the advantages and disadvantages of heterogeneous tissue transplantation. We hope that this review provides some suggestions for the future design of meniscus repair and regeneration strategies.

Outcomes of Osteochondral Allograft Transplantation With and Without Concomitant Meniscus Allograft Transplantation: A Comparative Matched Group Analysis.

BACKGROUND: Osteochondral allograft transplantation (OCA) is often performed with concomitant meniscus allograft transplantation (MAT) as a strategy for knee joint preservation, although to date, the effect of concomitant MAT on outcomes and failure rates after OCA has not been assessed. PURPOSE: To determine clinical outcomes for patients undergoing OCA with MAT as compared with a matched cohort of patients undergoing isolated OCA. STUDY DESIGN: Control study; Level of evidence, 3. METHODS: Patients who underwent OCA of the medial or lateral femoral condyle without concomitant MAT by a single surgeon were compared with a matched group of patients who underwent OCA with concomitant MAT (ipsilateral compartment). The patients were matched per age, sex, body mass index, and number of previous ipsilateral knee operations ±1. Patient-reported outcomes, complications, reoperations, and survival rates were compared between groups. RESULTS: One hundred patients undergoing OCA (50 isolated, 50 with MAT) with a mean ± SD follow-up of 4.9 ± 2.7 years (minimum, 2 years) were included (age, 31.7 ± 9.8 years; 52% male). Significantly more patients underwent OCA to the medial femoral condyle (n = 59) than the lateral femoral condyle (n = 41, P < .0001). Patients underwent 2.7 ± 1.7 operations on the ipsilateral knee before OCA. There were no significant differences between the groups regarding reoperation rate (n = 18 for OCA with MAT, n = 17 for OCA without MAT, P = .834), time to reoperation (2.2 ± 2.4 years for OCA with MAT, 3.4 ± 2.7 years for OCA without MAT, P = .149), or failure rates (n = 7 [14%] for OCA with MAT, n = 7 [14%] for OCA without MAT, P > .999). There were no significant differences in patient-reported clinical outcome scores between the groups at final follow-up. There was no significant difference in failure rates between patients undergoing medial femoral condyle OCA (n = 12, 15.3%) and lateral femoral condyle OCA (n = 5, 12.2%, P = .665). CONCLUSION: These results imply that with appropriate surgical indications to address meniscus deficiency in patients otherwise indicated for OCA and despite the added surgical time and complexity of concomitant MAT, outcomes are favorable, with an 86% OCA graft survivorship at 5 years. This information can be used to counsel patients undergoing OCA with concomitant MAT as part of a knee joint preservation strategy.

Evaluating the effects of material properties of artificial meniscal implant in the human knee joint using finite element analysis.

Artificial meniscal implants may replace severely injured meniscus and restore the normal functionality of the knee joint. Implant material stiffness and shape influence the longevity of implantations. This study, using 3D finite element analysis, aimed to evaluate the effects of material stiffness variations of anatomically shaped artificial meniscal implant in the knee joint. Finite element simulations were conducted on five different cases including intact knee, medial meniscectomized knee, and the knee joint with the meniscal implant with three distinct material stiffness. Cartilage contact pressures, compression stresses, shear stresses, and implant kinematics (medial-lateral and posterior-anterior displacement) were evaluated for an axial compressive load of 1150 N at full extension. Compared to the meniscectomized knee, the knee joint with the meniscal implant induced lower peak cartilage contact pressure and reduced the cartilage regions loaded with contact pressures greater than the peak cartilage contact pressure induced by the intact knee. Results of the current study also demonstrate that cartilage contact pressures and implant displacement are sensitive to the implant material stiffness. The meniscal implant with a stiffness of 11 MPa restores the intact knee contact mechanics, thereby reducing the risk of physiological damage to the articular cartilage.

Joint Preservation Techniques in Orthopaedic Surgery.

CONTEXT: With increasing life expectancy, there is growing demand for preservation of native articular cartilage to delay joint arthroplasties, especially in younger, active patients. Damage to the hyaline cartilage of a joint has a limited intrinsic capacity to heal. This can lead to accelerated degeneration of the joint and early-onset osteoarthritis. Treatment in the past was limited, however, and surgical treatment options continue to evolve that may allow restoration of the natural biology of the articular cartilage. This article reviews the most current literature with regard to indications, techniques, and outcomes of these restorative procedures. EVIDENCE ACQUISITION: MEDLINE and PubMed searches relevant to the topic were performed for articles published between 1995 and 2016. Older articles were used for historical reference. This paper places emphasis on evidence published within the past 5 years. STUDY DESIGN: Clinical review. LEVEL OF EVIDENCE: Level 4. RESULTS: Autologous chondrocyte implantation and osteochondral allografts (OCAs) for the treatment of articular cartilage injury allow restoration of hyaline cartilage to the joint surface, which is advantageous over options such as microfracture, which heal with less favorable fibrocartilage. Studies show that these techniques are useful for larger chondral defects where there is no alternative. Additionally, meniscal transplantation can be a valuable isolated or adjunctive procedure to prolong the health of the articular surface. CONCLUSION: Newer techniques such as autologous chondrocyte implantation and OCAs may safely produce encouraging outcomes in joint preservation.