Microfracture and osteochondral autograft transplantation are cost-effective treatments for articular cartilage lesions of the distal femur

Epidemiology of pediatric cartilage restoration procedures in the United States: insurance and geography play a role

OBJECTIVES

The purpose of this study is to analyze the epidemiology of children and adolescents undergoing osteochondral autograft transplantation (OAT), osteochondral allograft transplantation (OCA), and autologous chondrocyte implantation (ACI) in the United States.

METHODS

The Pediatric Health Information System, a national database consisting of 49 children's hospitals, was queried for all patients undergoing OAT, OCA, and ACI between 2012 and 2018. Demographic information was collected for each subject. United States Census guidelines were used to categorize hospitals geographically. Univariate analysis was followed by purposeful entry multivariate regression to adjust for confounding factors.

RESULTS

A total of 809 subjects with a mean age of 15.4 ± 2.4 years were included in the analysis. Of these, 48.6% underwent OCA, 41.9% underwent OAT, and 9.5% underwent ACI. After adjusting for confounders in a multivariate model, ACI was 3.6 times more likely to be performed in patients with private insurance than those that were publicly insured (95% CI 1.6-8.0, p = 0.002). Furthermore, a patient in the Northeast was 33.1 times more likely to undergo ACI than in the West (95% CI 4.5-246.1, p = 0.001). OAT was performed most frequently in the West and Midwest (52.4% and 51.8% of the time, respectively; p < 0.001).

CONCLUSION

In the United States, there is substantial variation in the procedures performed for cartilage restoration in children and adolescents. Though ACI is the least commonly selected operation overall, it is significantly more likely to be performed on patients with private insurance and those in the Northeast.

Comparative efficacy of osteochondral autologous transplantation and microfracture in the knee: an updated meta-analysis of randomized controlled trials

INTRODUCTION

More than 19% of patients undergoing knee arthroscopies suffers from articular cartilage defects. The chondral or osteochondral lesion has negative impacts on the knee joints function and the life quality of patients. However, the treatment remains challenging as hyaline cartilage is not renewable. The purpose of this study was to systematically analyze the data of randomized controlled trials for comparing the postoperative outcomes between osteochondral autologous transplantation (OAT) and microfracture (MF) procedure. We hypothesized that the outcomes were better in OAT than MF procedure.

MATERIALS AND METHODS

A systematic literature search of the EMBASE, Pubmed, and Cochrane Library databases was conducted based on PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The outcome measures include: the rate of excellent or good results, the rate of return to sports, the failure rate, osteoarthritis rate, International Cartilage Repair Society (ICRS) score, Lysholm Knee Score, and Tegner scale. The statistical analysis was completed using Review Manager (RevMan, version 5.3) software.

RESULTS

The systematic search identified 7 studies with a total of 346 patients. The pooled result showed significant differences between the two groups in the rate of return to sports and failure. The following outcome scores showed significant improvement (pre- vs postoperatively): Lysholm score (p = 0.02), Tegner scale (p < 0.00001), and ICRS score (p < 0.00001). The differences were not significant in the excellent or good results and the rate of osteoarthritis.

CONCLUSION

The patients in OAT group may return to play quicker, even return to pre-injury level of activity compared to the MF group. OAT is better than MF procedure in accordance with Lysholm score, Tegner score, ICRS score, and the rate of failure. However, few studies have reported long-term outcomes and there has no uniform criteria for safe return to sports. Further research is needed.

LEVEL OF EVIDENCE

Level II, meta-analysis of randomized controlled trials.

3D printed porous sulfonated polyetheretherketone scaffold for cartilage repair: Potential and limitation

Objective

The treatment of cartilage lesions has always been a difficult problem. Although cartilage tissue engineering provides alternative treatment options for cartilage lesions, biodegradable tissue engineering scaffolds have limitations.

Methods

In this study, we constructed a porous PEEK scaffold via 3D printing, surface-engineered with concentrated sulfuric acid for 15 s (SPK-15), 30 s (SPK-30), and 60 s (SPK-60). We systematically evaluated the physical and chemical characteristics and biofunctionalities of the scaffolds, and then evaluated the macrophage polarization modulating ability and anti-inflammatory effects of the sulfonated PEEK, and observed the cartilage-protective effect of SPK using a co-culture study. We further evaluated the repair effect of PEEK and SPK by implanting the prosthetic scaffold into a cartilage defect in a rabbit model.

Results

Compared to the PEEK, SPK-15 and SPK-60 scaffolds, SPK-30 has a good micro/nanostructure, appropriate biomechanical properties (compressive modulus, 43 ± 5 MPa; Shaw hardness, 20.6 ± 1.3 HD; close to native cartilage, 30 ± 8 MPa, 17.8 ± 0.8 HD), and superior biofunctionalities. Compared to PEEK, sulfonated PEEK can favor macrophage polarization to the M2 phenotype, which increases anti-inflammatory cytokine secretion. Furthermore, SPK can also prevent macrophage-induced cartilage degeneration. The in-vivo animal experiment demonstrates that SPK can favor new tissue ingrowth and integration, prevent peri-scaffold cartilage degeneration and patellar cartilage degeneration, inhibit inflammatory cytokine secretion, and promote cartilage function restoration.

Conclusion

The present study confirmed that the 3D printed porous sulfonated PEEK scaffold could promote cartilage functional repair, and suggests a new promising strategy for treating cartilage defects with a functional prosthesis that spontaneously inhibits nearby cartilage degeneration.

Translational potential of this article

In the present study, we propose a new cartilage repair strategy based on a porous, non-biodegradable polyetheretherketone (PEEK) scaffold, which may bring up a new treatment route for elderly patients with cartilage lesions in the future.

Small Ruminant Models for Articular Cartilage Regeneration by Scaffold-Based Tissue Engineering

Animal models play an important role in preclinical studies, especially in tissue engineering scaffolds for cartilage repair, which require large animal models to verify the safety and effectiveness for clinical use. The small ruminant models are most widely used in this field than other large animals because they are cost-effective, easy to raise, not to mention the fact that the aforementioned animal presents similar anatomical features to that of humans. This review discusses the experimental study of tissue engineering scaffolds for knee articular cartilage regeneration in small ruminant models. Firstly, the selection of these scaffold materials and the preparation process in vitro that have been already used in vivo are briefly reviewed. Moreover, the major factors influencing the rational design and the implementation as well as advantages and limitations of small ruminants are also demonstrated. As regards methodology, this paper applies principles and methods followed by most researchers in the process of experimental design and operation of this kind. By summarizing and comparing different therapeutic concepts, this paper offers suggestions aiming to increase the effectiveness of preclinical research using small ruminant models and improve the process of developing corresponding therapies.

Microfracture for the Treatment of Symptomatic Cartilage Lesions of the Knee: A Survey of International Cartilage Regeneration & Joint Preservation Society

OBJECTIVE

The purpose of this study was to describe the current practice trends for managing symptomatic cartilage lesions of the knee with microfracture among ICRS (International Cartilage Regeneration & Joint Repair Society) members.

DESIGN

A 42-item electronic questionnaire was sent to all ICRS members, which explored indications, surgical technique, postoperative management, and outcomes of the microfracture procedure for the treatment of symptomatic, full thickness chondral and osteochondral defects of the knee. Responses were compared between surgeons from different regions and years of practice.

RESULTS

A total of 385 surgeons answered the questionnaire. There was a significant difference noted in the use of microfracture among surgeons by region (P < 0.001). There was no association between the number of years in practice and the self-reported proportion of microfracture cases performed (P = 0.37). Fifty-eight subjects (15%) indicated that they do not perform microfracture at all. Regarding indication for surgery, 56% of surgeons would limit their indication of microfracture to lesions measuring 2 cm² or less. Half of the surgeons reported no upper age or body mass index limit. Regarding surgical technique, 90% of surgeons would recommend a formal debridement of the calcified layer and 91% believe it is important to create stable vertical walls. Overall, 47% of surgeons use biologic augmentation, with no significant difference between regions (P = 0.35) or years of practice (P = 0.67). Rehabilitation protocols varied widely among surgeons.

CONCLUSIONS

Indications, operative technique, and rehabilitation protocols utilized for patients undergoing microfracture procedures vary widely among ICRS members. Regional differences and resources likely contribute to these practice pattern variations.

Controlled domain gels with a biomimetic gradient environment for osteochondral tissue regeneration

In order to repair an osteochondral defect, it is critical to advance a bi-lineage constructive scaffold with gradient transition. In this study, we developed a simple and straightforward approach for fabricating a multi-domain gel scaffold through the assembly/disassembly of low-molecular-weight gels (LMWGs) inside a stable PEGDA network by photopolymerization. The versatility of this technology enabled to vary biological, topological, and mechanical properties through material selection and to generate a chondrogenic-osteogenic gradient transition. The multi-domain gel exhibited an increasing stiffness gradient along the longitudinal direction from the cartilage layer at approximately 20 kPa to the bone layer at approximately 300 kPa as well as spatial variation at the gradient interface. Moreover, the transitional layer with a condensed structure and intermediate stiffness prevented delamination of the contrasting layers and maintained microenvironmental differences in the upper and lower layers. The in vitro results indicated that each domain had an individual capacity to spatially control the differentiation of MSCs toward osteoblastic lineage and chondrocytic lineage. This was mainly because the mechanical and topographical cues from the respective domains played an important role in modulating the Rho-ROCK signaling pathway, whereas the blockage of ROCK signals significantly impaired domain-modulated osteogenesis and enhanced chondrogenesis. Additionally, the quantity and quality of osteochondral repair were evaluated at 4 and 8 weeks through histological analysis and micro-computed tomography (micro-CT). The results indicated that the multi-domain gels distinctly improved the regeneration of subchondral bone and cartilage tissues. Overall, the outcomes of this study can motivate future bioinspired gradient and heterogeneity strategies for osteochondral tissue regeneration. STATEMENT OF SIGNIFICANCE: The regeneration of osteochondral defects remains a major challenge due to the complexity of osteochondral structure and the limited self-repair capacity of cartilage. The gradient design to mimic the transition between the calcified cartilage and the subchondral bone plate as well as the zones of cartilage is an effective strategy. In this study, controlled multi-domain gels were fabricated through the assembly/disassembly of low-molecular-weight gels inside a stable PEGDA network by photopolymerization. The prepared multi-domain gels showed a chondrogenic-osteogenic gradient transition, which decreased the possibility of delamination and stimulated osteochondral tissue regeneration in vivo. Overall, our study promotes new strategies of bioinspired gradients and heterogeneities for more challenging applications.

Effects of unloader bracing on clinical outcomes and articular cartilage regeneration following microfracture of isolated chondral defects: a randomized trial

PURPOSE

To determine whether the use of an unloading brace can increase the thickness of cartilage regenerate after microfracture surgery.

METHODS

This is a randomized (1:1) controlled clinical trial. Twenty-four patients who underwent microfracture between 2012 and 2015 were identified and were randomly assigned to an unloading brace group or a no-brace group. All patients were kept non-weight bearing for the first eight weeks after surgery and then patients in the intervention group began using an unloading brace for an average of 63.9 (SD = 41.6) days to protect clot stability by exerting a varus or valgus force on the knee to decrease the force on the knee's lateral or medial compartment, respectively. Quality of the cartilage repair was assessed with knee magnetic resonance imaging to determine repair tissue thickness (primary outcome), repair tissue volume, and T2 relaxation times at 12 and 24 months after surgery. Clinical outcomes were evaluated with KOOS, Tegner, SF12, and Lysholm questionnaires at six, 12 and 24 months after surgery.

RESULTS

Three patients were lost to follow-up, resulting in 21 patients ultimately analyzed. The unloading brace repair tissue was greater than the no-brace group in volume (26.8 ± 23.7 mm³ vs - 8.4 ± 22.7 mm³, p = 0.005) and thickness (0.2 ± 0.2 mm versus - 0.4 ± 0.3 mm, p = 0.001) at 12 months and in cartilage thickness in the unloading brace group at 24 months (0.4 ± 0.4 mm versus - 0.1 ± 0.3 mm, p = 0.029). There was a positive correlation between wearing the brace longer and improved 6-month KOOS symptom scores (r = 0.82, p = 0.013), 6-month KOOS QOL scores (r = 0.80, p = 0.017), 6-month Tegner scores (r = 0.94, p = 0.002), and Tegner score changes from baseline to 6 months (r = 0.80, p = 0.032).

CONCLUSION

This study found a significant mid-term increase in cartilage repair tissue thickness following unloading bracing in patients recovering from microfracture for isolated chondral defects.

LEVEL OF EVIDENCE

II.

Studies of Articular Cartilage Repair from 2009 to 2018: A Bibliometric Analysis of Articles

Objective

To perform a bibliometric analysis of research on articular cartilage repair published in Chinese and English over the past decade. Fundamental and clinical research topics of high interest were further comparatively analyzed.

Methods

Relevant studies published from 1 January 2009 to 31 December 2018 (10 years) were retrieved from the Wanfang database (Chinese articles) and six databases, including MEDLINE, WOS, INSPEC, SCIELO, KJD, and RSCI on the website “Web of Science” (English articles), using key words: “articular cartilage” AND “injury” AND “repair”. The articles were categorized according to research focuses for a comparative analysis between those published in Chinese vs English, and further grouped according to publication date (before and after 2014). A comparative analysis was performed on research focus to characterize the variation in research trends between two 5‐year time spans. Moreover, articles were classified as basic and clinical research studies.

Results

Overall, 5762 articles were retrieved, including 2748 in domestic Chinese journals and 3014 in international English journals. A total of 4937 articles focused on the top 10 research topics, with the top 3 being stem cells (32.1%), tissue‐engineered scaffold (22.8%), and molecular mechanisms (16.4%). Differences between the numbers of Chinese and English papers were observed for 3 topics: chondrocyte implantation (104 vs 316), osteochondral allograft (27 vs 86), and microfracture (127 vs 293). The following topics gained more research interest in the second 5‐year time span compared with the first: microfracture, osteochondral allograft, osteochondral autograft, stem cells, and tissue‐engineered scaffold. Articles with a focus on three‐dimensional‐printing technology have shown the fastest increase in publication numbers. Among 5613 research articles, basic research studies accounted for the majority (4429), with clinical studies described in only 1184 articles. The top 7 research topics of clinical studies were: chondrocyte implantation (28.7%), stem cells (21.9%), microfracture (19.2%), tissue scaffold (10.6%), osteochondral autograft (10.5%), osteochondral allograft (6.3%), and periosteal transplantation (2.8%).

Conclusion

Studies focused on stem cells and tissue‐engineered scaffolds led the field of damaged articular cartilage repair. International researchers studied allograft‐related implantation approaches more often than Chinese researchers. Traditional surgical techniques, such as microfracture and osteochondral transplantation, gained high research interest over the past decade.

Return-to-Sport Review for Current Cartilage Treatments

The return to play outcome is an important measure for orthopaedic sports medicine treatments. This variable is especially important when discussing cartilage treatments because there are many different cartilage options available to athletes with articular injuries and this population is particularly interested in the ability to return to activities. Although many outcome variables are considered in any surgical procedure, the return-to-sport variable is focused on an active population and can be tailored to that patient's sport-specific goals. In this article, we will review some of the most recent and up-to-date articles describing return-to-sport outcomes for various knee cartilage treatments. This article will focus on the most common current knee cartilage treatments including microfracture, autologous chondrocyte implantation, osteochondral autograft transplant, and osteochondral allograft transplantation.

Cost-efficacy of Knee Cartilage Defect Treatments in the United States

BACKGROUND

Multiple knee cartilage defect treatments are available in the United States, although the cost-efficacy of these therapies in various clinical scenarios is not well understood.

PURPOSE/HYPOTHESIS

The purpose was to determine cost-efficacy of cartilage therapies in the United States with available mid- or long-term outcomes data. The authors hypothesized that cartilage treatment strategies currently approved for commercial use in the United States will be cost-effective, as defined by a cost <$50,000 per quality-adjusted life-year over 10 years.

STUDY DESIGN

Systematic review.

METHODS

A systematic search was performed for prospective cartilage treatment outcome studies of therapies commercially available in the United States with minimum 5-year follow-up and report of pre- and posttreatment International Knee Documentation Committee subjective scores. Cost-efficacy over 10 years was determined with Markov modeling and consideration of early reoperation or revision surgery for treatment failure.

RESULTS

Twenty-two studies were included, with available outcomes data on microfracture, osteochondral autograft, osteochondral allograft (OCA), autologous chondrocyte implantation (ACI), and matrix-induced ACI. Mean improvement in International Knee Documentation Committee subjective scores at final follow-up ranged from 17.7 for microfracture of defects >3 cm² to 36.0 for OCA of bipolar lesions. Failure rates ranged from <5% for osteochondral autograft for defects requiring 1 or 2 plugs to 46% for OCA of bipolar defects. All treatments were cost-effective over 10 years in the baseline model if costs were increased 50% or if failure rates were increased an additional 15%. However, if efficacy was decreased by a minimum clinically important amount, then ACI (periosteal cover) of femoral condylar lesions ($51,379 per quality-adjusted life-year), OCA of bipolar lesions ($66,255) or the patella ($66,975), and microfracture of defects >3 cm² ($127,782) became cost-ineffective over 10 years.

CONCLUSION

Currently employed treatments for knee cartilage defects in the United States are cost-effective in most clinically acceptable applications. Microfracture is not a cost-effective initial treatment of defects >3 cm². OCA transplantation of the patella or bipolar lesions is potentially cost-ineffective and should be used judiciously.

Health State Utilities in Children and Adolescents With Osteochondritis Dissecans of the Knee

Background:

The impact of osteochondritis dissecans (OCD) lesions of the knee on a child’s health-related quality of life has not previously been quantified. Preference-based health utility assessment allows patients to assign quality-of-life valuations (utilities) to different health states and conditions.

Purpose:

To determine (1) patient-reported utility scores for health states associated with pediatric OCD lesions of the knee and (2) whether these scores are associated with patient demographics or disease severity.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

Children, adolescents, and young adults being treated for OCD of the knee were interviewed to assess utilities for each of the 6 health states commonly encountered in the treatment of OCD: (1) symptomatic lesion, (2) nonoperative rehabilitation, (3) postoperative rehabilitation, (4) intermediate treatment success, (5) early degenerative knee changes, and (6) successful treatment (asymptomatic). Patients were asked to assign health utilities to each state using a standardized feeling thermometer (scale, 0-100), which were converted to a health state utility (scale, 0-1 [1 = perfect health]). Utilities were reported with descriptive statistics, and comparative analyses were performed to test whether assignments were associated with patient age, sex, or whether the OCD lesion required surgical intervention.

Results:

A total of 100 participants treated or undergoing treatment for OCD were prospectively enrolled; 74% were male (n = 74). The median age at the time of survey was 15 years (interquartile range, 13-16.5 years). Utility scores were as follows: symptomatic OCD lesion, 0.15; nonoperative rehabilitation, 0.30; postoperative rehabilitation, 0.30; early degenerative changes, 0.58; intermediate treatment success, 0.65; and successful treatment, 1.0. Utility scores were not associated with age, sex, or whether the participant underwent surgical treatment for the OCD lesion.

Conclusion:

The current study quantified patient-reported utilities for 6 OCD lesion health states, which may be used for future health-related quality of life, decision analysis, and quality/safety/value studies. These utility scores were stable and not affected by patient age, sex, or treatment strategy.

Comparative Effectiveness of Cartilage Repair With Respect to the Minimal Clinically Important Difference

BACKGROUND

Recent studies demonstrated a 5% increase in cartilage repair procedures annually in the United States. There is currently no consensus regarding a superior technique, nor has there been a comprehensive evaluation of postoperative clinical outcomes with respect to a minimal clinically important difference (MCID).

PURPOSE

To determine the proportion of available cartilage repair studies that meet or exceed MCID values for clinical outcomes improvement over short-, mid-, and long-term follow-up.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

A systematic review was performed via the Medline, Scopus, and Cochrane Library databases. Available studies were included that investigated clinical outcomes for microfracture (MFX), osteoarticular transfer system (OATS), osteochondral allograft transplantation, and autologous chondrocyte implantation/matrix-induced autologous chondrocyte implantation (ACI/MACI) for the treatment of symptomatic knee chondral defects. Cohorts were combined on the basis of surgical intervention by performing a meta-analysis that utilized inverse-variance weighting in a DerSimonian-Laird random effects model. Weighted mean improvements in International Knee Documentation Committee (IKDC), Lysholm, and visual analog scale for pain (VAS pain) scores were calculated from preoperative to short- (1-4 years), mid- (5-9 years), and long-term (≥10 years) postoperative follow-up. Mean values were compared with established MCID values per 2-tailed 1-sample Student t tests.

RESULTS

A total of 89 studies with 3894 unique patients were analyzed after full-text review. MFX met MCID values for all outcome scores at short- and midterm follow-up with the exception of VAS pain in the midterm. OATS met MCID values for all outcome scores at all available time points; however, long-term data were not available for VAS pain. Osteochondral allograft transplantation met MCID values for IKDC at short- and midterm follow-up and for Lysholm at short-term follow-up, although data were not available for other time points or for VAS pain. ACI/MACI met MCID values for all outcome scores (IKDC, Lysholm, and VAS pain) at all time points.

CONCLUSION

In the age of informed consent, it is important to critically evaluate the clinical outcomes and durability of cartilage surgery with respect to well-established standards of clinical improvement. MFX failed to maintain VAS pain improvements above MCID thresholds with follow-up from 5 to 9 years. All cartilage repair procedures met MCID values at short- and midterm follow-up for IKDC and Lysholm scores; ACI/MACI and OATS additionally met MCID values in the long term, demonstrating extended maintenance of clinical benefits for patients undergoing these surgical interventions as compared with MFX.

The Subchondral Bone Is Affected by Bone Marrow Stimulation: A Systematic Review of Preclinical Animal Studies

OBJECTIVE

Despite the mechanical and biological roles of subchondral bone (SCB) in articular cartilage health, there remains no consensus on the postoperative morphological status of SCB following bone marrow stimulation (BMS). The purpose of this systematic review was to clarify the morphology of SCB following BMS in preclinical, translational animal models.

DESIGN

The MEDLINE and EMBASE databases were systematically reviewed using specific search terms on April 19, 2016 based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The morphology of the SCB was assessed using of microcomputed tomography (bone density) and histology (microscopic architecture).

RESULTS

Seventeen animal studies with 520 chondral lesions were included. The morphology of SCB did not recover following BMS. Compared with untreated chondral defects, BMS resulted in superior morphology of superficial SCB and cartilage but inferior morphology (specifically bone density, P < 0.05) of the deep SCB. Overall, the use of biological adjuvants during BMS resulted in the superior postoperative morphology of SCB.

CONCLUSIONS

Alterations in the SCB following BMS were confirmed. Biologics adjuvants may improve the postoperative morphology of both SCB and articular cartilage. Refinements of BMS techniques should incorporate consideration of SCB damage and restoration. Investigations to optimize BMS techniques incorporating both minimally invasive approaches and biologically augmented platforms are further warranted.

Healing of Osteochondral Defects via Endochondral Ossification in an Ovine Model

OBJECTIVE

The objective of this study was to describe the mechanism of healing of osteochondral defects of the distal femur in the sheep, a commonly used translational model. Information on the healing mechanism be useful to inform the design of tissue engineering devices for joint surface defect repair.

DESIGN

A retrospective study was conducted examining 7-mm diameter osteochondral defects made in the distal medial femoral condyle of 40 adult female sheep, comprising control animals from 3 separate structures. The healing of the defects was studied at post mortem at up to 26 weeks.

RESULTS

Osteochondral defects of the distal femur of the sheep heal through endochondral ossification as evidenced by chondrocyte hypertrophy and type X collagen expression. Neocartilage is first formed adjacent to damaged cartilage and then streams over the damaged underlying bone before filling the defect from the base upward. No intramembranous ossification or isolated mesenchymal stem cell aggregates were detected in the healing tissue. No osseous hypertrophy was detected in the defects.

CONCLUSIONS

Osteochondral defects of the medial femoral condyle of the sheep heal via endochondral ossification, with neocartilage first appearing adjacent to damaged cartilage. Unlike the mechanism of healing in fracture repair, neocartilage is eventually formed directly onto damaged bone. There was most variability between animals between 8 and 12 weeks postsurgery. These results should be considered when designing devices to promote defect healing.

Orthopedic Surgical Options for Joint Cartilage Repair and Restoration

The limited natural capacity for articular cartilage to regenerate has led to a continuously broadening array of surgical interventions. Used once patients' symptoms are not relieved by nonoperative management, these share the goals of joint preservation and restoration. Techniques include bone marrow stimulation, whole-tissue transplantation, and cell-based strategies, each with its own variations. Many of these interventions are performed arthroscopically or with extended-portal techniques. Indications, operative techniques, unique benefits, and limitations are presented.

Primary Versus Secondary Osteochondral Autograft Transplantation for the Treatment of Large Osteochondral Lesions of the Talus

BACKGROUND

Recent studies have reported promising clinical results after osteochondral autograft transplantation (OAT) for the treatment of large osteochondral lesions of the talus (OLT). However, no study has yet compared clinical outcomes between primary and secondary OAT for large OLT.

PURPOSE

To compare clinical outcomes among patients with large OLT who receive primary OAT versus those who receive secondary OAT after failure of marrow stimulation and to identify factors associated with clinical failure.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

From 2005 to 2014, 46 patients with large OLT (≥150 mm²) underwent OAT: 18 underwent OAT as initial surgical management (primary OAT group), and 28 patients underwent secondary OAT after failure of previous arthroscopic marrow stimulation (secondary OAT group). In both groups, OAT procedures included arthroscopic inspection and debridement of concomitant soft tissue injuries. Clinical outcomes were assessed using pain visual analog scale (VAS), the Roles and Maudsley score, Foot and Ankle Outcome Scores (FAOS), and revisional surgery rates. Factors associated with clinical failures were evaluated using bivariate and logistic regression analyses. Survival outcomes were compared using Kaplan-Meier analysis.

RESULTS

Mean follow-up time was 6 years (range, 2-10.8 years). Mean lesion size was 194.9 mm² (range, 151.7-296.3 mm²). There were no significant differences between groups in patient demographics and preoperative findings. Postoperative pain VAS, Roles and Maudsley score, FAOS, and revisional surgery rates were not significantly different at last follow-up. Prior marrow stimulation was not significantly associated with clinical failure on bivariate analysis. Lesion size greater than 225 mm² on preoperative magnetic resonance imaging was significantly associated with clinical failure. Survival probabilities from Kaplan-Meier plots were not significantly different between the primary and secondary OAT groups ( P = .947).

CONCLUSION

Clinical outcomes of patients with large OLT treated with secondary OAT after failed marrow stimulation were found to be comparable with those who were treated with primary OAT. These results may be helpful to orthopaedic surgeons deciding appropriate surgical options for patients with large OLT.

Microfracture is more cost-effective than autologous chondrocyte implantation: a review of level 1 and level 2 studies with 5 year follow-up

PURPOSE

Focal cartilage defects in the knee may have devastating effect on the knee joint, where two of the main surgical treatment options are microfracture and autologous chondrocyte implantation. Comparative studies have failed to establish which method yields the best clinical results. A cost-effectiveness analysis of microfracture and autologous chondrocyte implantation would contribute to the clinical decision process.

METHODS

A PubMed search identifying level I and level II studies with 5 year follow-up was performed. With the data from these studies, decision trees with associated service provision and costs connected to the two different techniques were designed. In addition to hospital costs, we included costs connected to physiotherapy following surgery. To paint a broader cost picture, we also included indirect costs to the society due to productivity loss caused by work absence.

RESULTS

Four high-quality studies, with a follow-up of 5 years, met the inclusion criteria. A total of 319 patients were included, 170 undergoing microfracture and 149 autologous chondrocyte implantation. The re-operation rate was 23 (13.5%) following microfracture, and 18 (12.1%) for autologous chondrocyte implantation. Both groups achieved substantially better clinical scores at 5 years compared to baseline. Microfracture was more cost-effective when comparing all clinical scores.

CONCLUSION

Microfracture is associated with both lower costs and lower cost per point increase in patient reported outcome measures. There is a need of well-designed, high-quality randomized controlled trials before reliable conclusions regarding cost-effectiveness in the long run is possible.

LEVEL OF EVIDENCE

III.

Decellularized Hydrogels in Bone Tissue Engineering: A Topical Review

Nowadays, autograft and allograft techniques represent the main solution to improve bone repair. Unfortunately, autograft technique is expensive, invasive and subject to infections and hematoma, frequently affecting both donor sites and surgical sites. A recent advance in tissue engineering is the fabrication of cell-laden hydrogels with custom-made geometry, depending on the clinical case. The use of ECM (Extra-Cellular Matrix)-derived Hydrogels from bone tissue is the new opportunity to obtain good results in bone regeneration. Several micro-engineering techniques and approaches are available to fabricate different cell gradients and zonal structures in hydrogels design, in combination with the advancement in biomaterials selection. In this review, we analyse the stereolithografy, the Bio-patterning, the 3D bioprinting and 3D assembly, the Laser-Induced Forward Transfer Bioprinting (LIFT), the Micro-extrusion bioprinting, the promising Electrospinning technology, the Microfluidics and the Micromolding. Several mechanical properties are taken into account for bone regeneration scaffolds. However, each typology of scaffold presents some advantages and some concerns. The research on biomaterials is the most promising for bone tissue engineering: the new biomimetic materials will allow us to obtain optimal results in the next clinical application of basic research.

Long-term clinical follow-up of microfracture versus mosaicplasty in articular cartilage defects of medial femoral condyle

BACKGROUND

The purpose of this study was to evaluate the outcome after cartilage repair surgery in focal defects of the knee by microfracture versus mosaicplasty.

METHODS

A cohort of 102 patients undergoing microfracture (n=52) or mosaicplasty (n=50) of a single articular cartilage defect in the medial femoral condyle of ≤50mm² was evaluated by Lysholm score before surgery, at six months, 12months, five years, 10years, and 15-18years after surgery.

RESULTS

Median age of patients at the time of surgery was 36years (range 16-58) and median follow-up time was 16years (range 14-18). Defects were treated with a median size of three square centimetres (range one to five). A significant increase was seen in the Lysholm score from mean 48 (SD 16) at baseline to 66 (SD 23; P<0.001) at the 15-18year follow-up. The Lysholm score was higher in the mosaicplasty group at six months, 12months, five years and 10years (P<0.05 for all comparisons). These differences were clinically significant at all points (>10 points). However, at the final follow-up, the difference (eight points) did not reach statistical significance.

CONCLUSIONS

In the short-term, medium-term and long-term (10years), mosaicplasty in a single cartilage defect size one to five square centimetres of the femoral condyle resulted in clinically relevant better outcome than microfracture. However, at 15-18years after the surgery such a difference could not be found. In the six month to 10-15year (after surgery) perspective, the mosaicplasty procedure offered a better outcome in this type of lesion.

LEVEL OF EVIDENCE

Level III.

Return to sport after the surgical management of articular cartilage lesions in the knee: a meta-analysis

PURPOSE

Optimal surgical treatment of chondral defects in an athletic population remains highly controversial and has yet to be determined. The purpose of this review was to (1) report data on return to sport and (2) compare activity and functional outcome measures following various cartilage restoration techniques.

METHODS

A comprehensive review was performed for studies with return-to-sport outcomes after microfracture (MFX), osteochondral autograft transfer (OAT), osteochondral allograft transplantation (OCA), and autologous chondrocyte implantation (ACI). All studies containing return-to-sport participation with minimum 2-year post-operative activity-based outcomes were included. A meta-analysis comparing rate of return to sport between each surgical intervention was conducted using a random-effects model.

RESULTS

Forty-four studies met inclusion criteria (18 Level I/II, 26 Level III/IV). In total, 2549 patients were included (1756 M, 793 F) with an average age of 35 years and follow-up of 47 months. Return to sport at some level was 76 % overall, with highest rates of return after OAT (93 %), followed by OCA (88 %), ACI (82 %), and MFX (58 %). Osteochondral autograft transfer showed the fastest return to sports (5.2 ± 1.8 months) compared to 9.1 ± 2.2 months for MFX, 9.6 ± 3.0 months for OCA and 11.8 ± 3.8 months for ACI (P < 0.001). A meta-regression was conducted due to heterogeneity in preoperative factors such as patient age, lesion size, and preoperative Tegner score. None of these factors were found to be significant determinants for rate of return to sport.

CONCLUSION

In conclusion, in this meta-analysis of 2549 athletes, cartilage restoration surgery had a 76 % return to sport at mid-term follow-up. Osteochondral autograft transfer offered a faster recovery and appeared to have a higher rate of return to preinjury athletics, but heterogeneity in lesion size, athlete age, and concomitant surgical procedures are important factors to consider when assessing individual athletes. This study reports on the rate of return to sport in athletes undergoing various procedures for symptomatic chondral defects.

LEVEL OF EVIDENCE

IV.

A Cost-Effectiveness Analysis of Surgical Treatment Modalities for Chondral Lesions of the Knee: Microfracture, Osteochondral Autograft Transplantation, and Autologous Chondrocyte Implantation

Background:

Numerous surgical options exist to treat chondral lesions in the knee, including microfracture (MFx), osteochondral autograft transplantation (OAT), first-generation autologous chondrocyte implantation (ACI-1), and next-generation ACI (ACI-2).

Purpose:

To compare the cost-effectiveness of MFx, OAT, and ACI-1. The secondary purpose of this study was to compare the functional outcomes of MFx, OAT, ACI-1, and ACI-2.

Study Design:

Systematic review; Level of evidence, 2.

Methods:

Two independent reviewers conducted an online literature search of 2 databases for level 1 and 2 studies using the Lysholm, International Knee Documentation Committee (IKDC), Knee injury and Osteoarthritis Outcome Score (KOOS), and/or Hospital for Special Surgery (HSS) Knee Score. A weighted mean difference in pre- to postoperative functional outcome score was calculated for each treatment. The mean per-patient costs associated with MFx, OAT, and ACI-1 were determined from a recent publication based on review of a national private insurance database. The cost for each procedure was then divided by the weighted mean difference in functional outcome score to give the cost-per-point change in outcome score.

Results:

A total of 12 studies (6 level 1, 6 level 2) met the inclusion criteria for the functional outcome analysis, including 730 knees (MFx, n = 300; OAT, n = 90; ACI-1, n = 68; ACI-2, n = 272). The mean follow-up was not significantly different between groups (MFx, 29.4 months; OAT, 38.3 months; ACI-1, 19.0 months; ACI-2, 26.7 months). The mean increase in functional outcome score was 23 for MFx, 19 for OAT, 20 for ACI-1, and 35 for ACI-2. The change in functional outcome score was significantly greater for ACI-2 when compared with all other treatments (P < .0001). The cost-per-point change in functional outcome score was $200.59 for MFx, $313.84 for OAT, and $536.59 for ACI-1.

Conclusion:

MFx, OAT, ACI-1, and ACI-2 are effective surgical procedures for the treatment of cartilage defects in the knee. All 4 treatments led to an increase in functional outcome scores postoperatively with a short-term follow-up. ACI-2 had a statistically greater improvement in functional outcome scores as compared with the other 3 procedures. MFx was found to be the most cost-effective treatment option and ACI-1 the least cost-effective.

Accelerated Return to Sport After Osteochondral Autograft Plug Transfer

Background:

Previous studies have reported varying return-to-sport protocols after knee cartilage restoration procedures.

Purpose:

To (1) evaluate the time for return to sport in athletes with an isolated chondral injury who underwent an accelerated return-to-sport protocol after osteochondral autograft plug transfer (OAT) and (2) evaluate clinical outcomes to assess for any consequences from the accelerated return to sport.

Study Design:

Case series; Level of evidence, 4.

Methods:

An institutional cohort of 152 OAT procedures was reviewed, of which 20 competitive athletes met inclusion and exclusion criteria. All patients underwent a physician-directed accelerated rehabilitation program after their procedure. Return to sport was determined for all athletes. Clinical outcomes were assessed using International Knee Documentation Committee (IKDC) and Tegner scores as well as assessment of level of participation on return to sport.

Results:

Return-to-sport data were available for all 20 athletes; 13 of 20 athletes (65%) were available for clinical evaluation at a mean 4.4-year follow-up. The mean time for return to sport for all 20 athletes was 82.9 ± 25 days (range, 38-134 days). All athletes were able to return to sport at their previous level and reported that they were satisfied or very satisfied with their surgical outcome and ability to return to sport. The mean postoperative IKDC score was 84.5 ± 9.5. The mean Tegner score prior to injury was 8.9 ± 1.7; it was 7.7 ± 1.9 at final follow-up.

Conclusion:

Competitive athletes with traumatic chondral defects treated with OAT managed using this protocol had reduced time to preinjury activity levels compared with what is currently reported, with excellent clinical outcomes and no serious long-term sequelae.

Osteochondral Allograft Transplantation of the Knee: Analysis of Failures at 5 Years

BACKGROUND

Osteochondral allograft transplantation (OAT) is being performed with increasing frequency, and the need for reoperations is not uncommon.

PURPOSE

To quantify survival for OAT and report findings at reoperations.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A review of prospectively collected data of 224 consecutive patients who underwent OAT by a single surgeon with a minimum follow-up of 2 years was conducted. The reoperation rate, timing of reoperation, procedure performed, and findings at surgery were reviewed. Failure was defined by revision OAT, conversion to knee arthroplasty, or gross appearance of graft failure at second-look arthroscopic surgery.

RESULTS

A total of 180 patients (mean [±SD] age, 32.7 ± 10.4 years; 52% male) who underwent OAT with a mean follow-up of 5.0 ± 2.7 years met the inclusion criteria (80% follow-up). Of these, 172 patients (96%) underwent a mean of 2.5 ± 1.7 prior surgical procedures on the ipsilateral knee before OAT. Forty-eight percent of OAT procedures were isolated, while 52% were performed with concomitant procedures including meniscus allograft transplantation (MAT) in 65 (36%). Sixty-six patients (37%) underwent a reoperation at a mean of 2.5 ± 2.5 years, with 32% (21/66) undergoing additional reoperations (range, 1-3). Arthroscopic debridement was performed in 91% of patients with initial reoperations, with 83% showing evidence of an intact graft; of these, 9 ultimately progressed to failure at a mean of 4.1 ± 1.9 years. A total of 24 patients (13%) were considered failures at a mean of 3.6 ± 2.6 years after the index OAT procedure because of revision OAT (n = 7), conversion to arthroplasty (n= 12), or appearance of a poorly incorporated allograft at arthroscopic surgery (n = 5). The number of previous surgical procedures was independently predictive of reoperations and failure; body mass index was independently predictive of failure. Excluding the failed patients, statistically and clinically significant improvements were found in the Lysholm score, International Knee Documentation Committee score, Knee injury and Osteoarthritis Outcome Score, and Short Form-12 physical component summary at final follow-up ( P < .001 for all), with inferior outcomes (albeit overall improved) in patients who underwent a reoperation.

CONCLUSION

In this series, there was a 37% reoperation rate and an 87% allograft survival rate at a mean of 5 years after OAT. The number of previous ipsilateral knee surgical procedures was predictive of reoperations and failure. Of the patients who underwent arthroscopic debridement with an intact graft at the time of arthroscopic surgery, 82% experienced significantly improved outcomes, while 18% ultimately progressed to failure. This information can be used to counsel patients on the implications of a reoperation after OAT.

Pelleted Bone Marrow Derived Mesenchymal Stem Cells Are Better Protected from the Deleterious Effects of Arthroscopic Heat Shock

Introduction: The impact of arthroscopic temperature on joint tissues is poorly understood and it is not known how mesenchymal stem cells (MSCs) respond to the effects of heat generated by the device during the process of arthroscopy assisted experimental cell-based therapy. In the present study, we isolated and phenotypically characterized human bone marrow mesenchymal stem cells (hBMMSCs) from osteoarthritis (OA) patients, and evaluated the effect of arthroscopic heat on cells in suspension and pellet cultures.

Methods: Primary cultures of hBMMSCs were isolated from bone marrow aspirates of OA patients and cultured using DMEM supplemented with 10% FBS and characterized for their stemness. hBMMSCs (1 × 10⁶ cells) cultured as single cell suspensions or cell pellets were exposed to an illuminated arthroscope for 10, 20, or 30 min. This was followed by analysis of cellular proliferation and heat shock related gene expression.

Results: hBMMSCs were viable and exhibited population doubling, short spindle morphology, MSC related CD surface markers expression and tri-lineage differentiation into adipocytes, chondrocytes and osteoblasts. Chondrogenic and osteogenic differentiation increased collagen production and alkaline phosphatase activity. Exposure of hBMMSCs to an illuminated arthroscope for 10, 20, or 30 min for 72 h decreased metabolic activity of the cells in suspensions (63.27% at 30 min) and increased metabolic activity in cell pellets (62.86% at 10 min and 68.57% at 20 min). hBMMSCs exposed to 37, 45, and 55°C for 120 s demonstrated significant upregulation of BAX, P53, Cyclin A2, Cyclin E1, TNF-α, and HSP70 in cell suspensions compared to cell pellets.

Conclusions: hBMMSC cell pellets are better protected from temperature alterations compared to cell suspensions. Transplantation of hBMMSCs as pellets rather than as cell suspensions to the cartilage defect site would therefore support their viability and may aid enhanced cartilage regeneration.