Osteochondral autografts

In vitro and in vivo efficacy of naturally derived scaffolds for cartilage repair and regeneration

Intrinsically present bioactive cues allow naturally derived materials to mimic important characteristics of cartilage while also facilitating cellular recruitment, infiltration, and differentiation. Such traits are often what tissue engineers desire when they fabricate scaffolds, and yet, literature from the past decade is replete with examples of how most natural constructs with native biomolecules have only offered sub-optimal results in the treatment of cartilage defects. This paper provides an in-depth investigation of the performance of such scaffolds through a review of a collection of natural materials that have been used so far in repairing/regenerating articular cartilage. Although in vivo and clinical studies are the best indicators of scaffold efficacy, it was, however, observed that a large number of natural constructs had very promising scaffold characteristics to begin with, and would often show good in vitro/in vivo results. Finally, an examination of the biochemistry and biomechanics of repair tissues in studies that reported positive outcomes showed that these attributes often approached target cartilage values. The paper concludes with an outline of current trends as well as future directions for the field. STATEMENT OF SIGNIFICANCE: This review offers an exclusive focus on natural scaffold materials for cartilage repair and regeneration and provides a quantitative and qualitative analysis of their performance under a variety of in vitro and in vivo conditions. Readers can learn about environments where natural scaffolds have had the most success and tailor strategies to optimize their own work. Furthermore, given how the glycosaminoglycan (GAG) to hydroxyproline (HYP) ratio and moduli are fundamental attributes of hyaline cartilage, this paper adds to the body of knowledge by exploring how these characteristics reflect in preclinical outcomes. Such perspectives can greatly aid researchers better utilize natural materials for Cartilage Tissue Engineering (CTE).

Knee Cartilage Lesion Management-Current Trends in Clinical Practice

Many patients, particularly those aged above 40, experience knee joint pain, which hampers both sports activities and daily living. Treating isolated chondral and osteochondral defects in the knee poses a significant clinical challenge, particularly in younger patients who are not typically recommended partial or total knee arthroplasty as alternatives. Several surgical approaches have been developed to address focal cartilage defects. The treatment strategies are characterized as palliation (e.g., chondroplasty and debridement), repair (e.g., drilling and microfracture), or restoration (e.g., autologous chondrocyte implantation, osteochondral autograft, and osteochondral allograft). This review offers an overview of the commonly employed clinical methods for treating articular cartilage defects, with a specific focus on the clinical trials conducted in the last decade. Our study reveals that, currently, no single technology fully meets the essential requirements for effective cartilage healing while remaining easily applicable during surgical procedures. Nevertheless, numerous methods are available, and the choice of treatment should consider factors such as the location and size of the cartilage lesion, patient preferences, and whether it is chondral or osteochondral in nature. Promising directions for the future include tissue engineering, stem cell therapies, and the development of pre-formed scaffolds from hyaline cartilage, offering hope for improved outcomes.

Compressibility of Osteochondral Autograft Transfer Donor Grafts: A Comparison of Different Donor Regions and How Much Shortening Occurs of Plugs After Impaction

Background

Osteochondral autograft transfer (OAT) is a useful technique for full-thickness cartilage lesions of the distal femur. Various techniques recommend harvesting a plug 2 mm longer than the recipient hole to allow for graft impaction. Grafts with limited compressibility may not sit flush when impacted.

Purpose

To compare the compressibility/shortening of OAT donor plug regions from the distal femur of human cadaveric knees after impaction.

Study Design

Controlled laboratory study.

Methods

A total of 20 cadaveric knees (mean age, 70.3 ± 8.4 years) were divided into 4 donor regions: medial intercondylar (IC) notch, lateral IC notch, medial trochlea, and lateral trochlea. Each region was subdivided into 4 zones: far superior (FSZ), middle superior (MSZ), middle inferior (MIZ), and far inferior (FIZ). A total of 320 grafts (6-mm diameter, 15-mm depth) were extracted, and a custom-built machine was used to strike the graft 5 times using a predetermined energy of 0.11 J. The graft length was measured initially and after each impact. Statistical analysis of the compressibility for each of the 4 regions and all 16 zones was performed utilizing analysis of variance, with post hoc testing using the Fisher's least significant difference.

Results

Compression in the lateral IC notch, medial IC notch, medial trochlea, and lateral trochlea was 2.4 ± 1.5, 2.1 ± 0.7, 3.1 ± 2.2, and 2.1 ± 0.6 mm, respectively, with significant differences between the 4 regions (P < .01) and the most compression in the medial trochlea (P < .01). Subgroup analysis showed that the lateral trochlea had higher compressibility for FIZ versus MIZ (P = .02) and the lateral IC notch had higher compressibility for FSZ versus FIZ and MIZ (P < .05 for both).

Conclusion

Compressibility varied between OAT donor sites in the distal femur. OAT donor grafts showed the highest compressibility in the medial trochlea (3.1 mm) and lateral IC notch FSZ (3.0 mm).

Clinical Relevance

The lateral trochlea, medial IC notch, and the lower zones of the lateral IC notch grafts should not be oversized more than 2 mm in length, as these grafts may not compress adequately.

Current Reviews in Musculoskeletal Medicine: Current Controversies for Treatment of Meniscus Root Tears

PURPOSE OF REVIEW

The role of the meniscus in preserving the biomechanical function of the knee joint has been clearly defined. The hypothesis that meniscus root integrity is a prerequisite for meniscus function is supported by the development of progressive knee osteoarthritis (OA) following meniscus root tears (MRTs) treated either non-operatively or with meniscectomy. Consequently, there has been a resurgence of interest in the diagnosis and treatment of MRTs. This review examines the contemporary literature surrounding the natural history, clinical presentation, evaluation, preferred surgical repair technique and outcomes.

RECENT FINDINGS

Surgeons must have a high index of suspicion in order to diagnose a MRT because of the nonspecific clinical presentation and difficult visualization on imaging. Compared with medial MRTs that commonly occur in middle age/older patients, lateral meniscus root injuries tend to occur in younger males with lower BMIs, less cartilage degeneration, and with concomitant ligament injury. Subchondral insufficiency fractures of the knee have been found to be associated with both MRTs and following arthroscopic procedures. Meniscus root repair has demonstrated good outcomes, and acute injuries with intact cartilage should be repaired. Cartilage degeneration, BMI, and malalignment are important considerations when choosing surgical candidates. Meniscus centralization has emerged as a viable adjunct strategy aimed at correcting meniscus extrusion. Meniscus root repair results in a decreased rate of OA and arthroplasty and is economically advantageous when compared with nonoperative treatment and partial meniscectomy. The transtibial pull-through technique with the addition of centralization for the medial meniscus is associated with encouraging early results.

Arthroscopic Patellar Osteochondral Transplantation

The undersurface location of the patellar articular cartilage presents unique challenges to osteochondral defect treatment. Current osteochondral grafting techniques and instrumentation require arthrotomy and patellar eversion to access the defect with the necessary perpendicular trajectory. We describe an all-arthroscopic patellar osteochondral grafting technique, with transpatellar retrograde reaming for recipient socket creation and graft fixation, to treat focal patellar cartilage defects.

The Induced Pluripotent Stem Cells in Articular Cartilage Regeneration and Disease Modelling: Are We Ready for Their Clinical Use?

The development of induced pluripotent stem cells has brought unlimited possibilities to the field of regenerative medicine. This could be ideal for treating osteoarthritis and other skeletal diseases, because the current procedures tend to be short-term solutions. The usage of induced pluripotent stem cells in the cell-based regeneration of cartilage damages could replace or improve on the current techniques. The patient’s specific non-invasive collection of tissue for reprogramming purposes could also create a platform for drug screening and disease modelling for an overview of distinct skeletal abnormalities. In this review, we seek to summarise the latest achievements in the chondrogenic differentiation of pluripotent stem cells for regenerative purposes and disease modelling.

Return-to-Play and Rehabilitation Protocols following Cartilage Restoration Procedures of the Knee: A Systematic Review

OBJECTIVE

The purpose of this study is to systematically review the literature and to evaluate the reported rehabilitation protocols, return-to-play guidelines, and subsequent rates of return to play following cartilage restoration procedures in the knee.

DESIGN

MEDLINE, EMBASE, and the Cochrane Library were searched according to the PRISMA guidelines to find studies on cartilage restoration procedures in the knee, including (1) microfracture (Mfx), (2) osteochondral autograft transfer (AOT), (3) osteochondral allograft implantation (OCA), and (4) autologous chondrocyte implantation (ACI). Studies were included if they reported return-to-play data or rehabilitation protocols.

RESULTS

Overall, 179 studies fit our inclusion criteria, with 48 on Mfx, 34 on AOT, 54 on OCA, and 51 on ACI. The rate of return to play was reported as high as 88.2% with AOT, and as low as 77.2% following OCA, with rates of return to play at the same/higher level as high as 79.3% with AOT, and as low as 57.3% following ACI. The average reported time of return to play was as low as 4.9 months with AOT, and as high as 11.6 months following ACI.

CONCLUSIONS

The majority of patients are able to return to play following cartilage restoration procedures in the knee, regardless of surgical procedure utilized. However, while the rate of return to play at the same level was similar to the overall rate of return following AOT, there was a large number of patients unable to return to the same level following Mfx, OCA, and ACI. Additionally, there is wide variety in the rehabilitation protocols, and scant literature on return-to-play protocols.

Characterization of Osteogenesis and Chondrogenesis of Human Decellularized Allogeneic Bone with Mesenchymal Stem Cells Derived from Bone Marrow, Adipose Tissue, and Wharton's Jelly

Allogeneic bone grafts are a promising material for bone implantation due to reduced operative trauma, reduced blood loss, and no donor-site morbidity. Although human decellularized allogeneic bone (hDCB) can be used to fill bone defects, the research of revitalizing hDCB blocks with human mesenchymal stem cells (hMSCs) for osteochondral regeneration is missing. The hMSCs derived from bone marrow, adipose tissue, and Wharton’s jelly (BMMSCs, ADMSCs, and UMSCs, respectively) are potential candidates for bone regeneration. This study characterized the potential of hDCB as a scaffold for osteogenesis and chondrogenesis of BMMSCs, ADMSCs, and UMSCs. The pore sizes and mechanical strength of hDCB were characterized. Cell survival and adhesion of hMSCs were investigated using MTT assay and F-actin staining. Alizarin Red S and Safranin O staining were conducted to demonstrate calcium deposition and proteoglycan production of hMSCs after osteogenic and chondrogenic differentiation, respectively. A RT-qPCR was performed to analyze the expression levels of osteogenic and chondrogenic markers in hMSCs. Results indicated that BMMSCs and ADMSCs exhibited higher osteogenic potential than UMSCs. Furthermore, ADMSCs and UMSCs had higher chondrogenic potential than BMMSCs. This study demonstrated that chondrogenic ADMSCs- or UMSCs-seeded hDCB might be potential osteochondral constructs for osteochondral regeneration.

Reconstruction of Tibial Plateau Fracture Malunion in the Setting of a Large Cartilage Defect in an Adolescent: A Case Report

CASE

An 18-year-old adolescent boy presented with knee pain and stiffness secondary to tibial plateau valgus malunion and osteochondral defect, 8 months after initial injury/fixation. We opted for a novel technique that reconstructs the convex lateral tibial plateau by using osteotomy and an osteochondral autograft harvested from the lateral aspect of the ipsilateral femoral condyle.

CONCLUSION

The reported novel reconstruction technique is inexpensive, achievable with routine techniques, and demonstrated a favorable short-term outcome. At 3 years of follow-up, the patient had excellent, asymptomatic, left knee mobility and function with radiographic evidence of mild posttraumatic arthritis despite normal knee alignment.

[Update on the Operative Treatment of Cartilage Defects]

Focal cartilage defects lead to swelling, significant pain and loss of function of the affected joint. Additionally, they are linked to early onset of osteoarthritis. Often young and active patients are especially susceptible due to the high stress placed on their joints. A vast amount of treatment options is available to orthopaedic surgeons to cure cartilage defects of the knee, hip, shoulder, elbow and ankle joints. This article serves to give an overview of these available treatment options and to explain the expected outcomes.

Small Cartilage Defect Management

Cartilage defects in the knee are common resulting in significant pain and morbidity over time. These defects can arise in isolation or concurrently with other associated injuries to the knee. The treatment of small (< 2-3 cm²) cartilage deficiencies has changed as our basic science knowledge of tissue healing has improved. Advancements have led to the development of new and more effective treatment modalities. It is important to address any associated knee injuries and limb malalignment. Surgical options are considered when nonoperative treatment fails. The specific procedure depends on individual patient characteristics, lesion size, and location. Debridement/chondroplasty, microfracture, marrow stimulation plus techniques, fixation of unstable osteochondral fragments, osteochondral autograft transfer, and osteochondral allograft transplantation, all have roles in the treatment of small cartilage defects.

Current solutions for the treatment of chronic articular cartilage defects in the knee

Chondral and osteochondral defects in the knee are common and may lead to degenerative joint disease if treated inappropriately.

Conventional treatments such as microfracture often result in fibrocartilage formation and are associated with inferior results. Additionally, microfracture is generally unsuitable for the treatment of defects larger than 2–4 cm².

The osteochondral autograft transfer system (OATS) has been shown to produce superior clinical outcomes to microfracture but is technically difficult and may be associated with donor-site morbidity. Osteochondral allograft use is limited by graft availability and failure of cartilage incorporation is an issue.

Autologous chondrocyte implantation (ACI) has been shown to result in repair with hyaline-like cartilage but involves a two-stage procedure and is relatively expensive.

Rehabilitation after ACI takes 12 months, which is inconvenient and not feasible for athletic patients.

Newer methods to regenerate cartilage include autologous stem cell transplantation, which may be performed as a single-stage procedure, can have a shorter rehabilitation period and is less expensive than ACI. Longer-term studies of these methods are needed.

Cite this article: EFORT Open Rev 2020;5:156-163. DOI: 10.1302/2058-5241.5.190031

Concentration of Chondrogenic Soluble Factors in Freshly Harvested Lipoaspirate

BACKGROUND

Cartilage tissue has a limited capacity for healing with the consequence that patients are often treated symptomatically until they become candidates for osteotomy or total joint replacement. Alternative biological therapies, for example, application of platelet-rich plasma and implantation of chondrocytes and mesenchymal stem cells, have emerged as a new treatment modality to repair articular cartilage. In addition, autologous fat transfer is performed for treatment of cartilage defects, example given, in osteoarthrosis, but several questions regarding basic biochemical properties of the transplant remain unanswered. Bone morphogenetic protein 4 (BMP4), matrix metalloproteinase (MMP)-8, cartilage oligomeric matrix protein (COMP), and chitinase-3-like protein 1 (CHI3L1) have been shown to be involved in chondrogenic regeneration and represent potential therapeutic agents for cartilage repair. However, no study regarding naturally occurring levels of these soluble factors in transplanted adipose tissue has yet been performed.

METHODS

To investigate the influence of age, body mass index, donor site, and sex on the concentration of BMP4, MMP-8, COMP, and CHI3L1 in freshly aspirated adipose tissue, their content was measured by means of enzyme-linked immunosorbent assay readings.

RESULTS

There were significant quantities of BMP4, MMP-8, COMP, and CHI3L1 (23.6, 249.9, 298.0, and 540.6 pg/mg, respectively) in the lipoaspirate harvested for transplantation. There was no correlation between the content of soluble factors and the patients' age or body mass index. Furthermore, the sex did not affect the amount of the investigated factors. However, there were significantly lower contents of BMP4, COMP, and CHI3L1 found in lipoaspirates harvested from the abdomen compared with nonabdominal donor sites.

CONCLUSIONS

Naturally occurring differences in the concentrations of the investigated soluble factors will favor certain donor sites for autologous fat transfer in the field of cartilage repair. Thus, increasing knowledge will enable researchers and clinicians to make autologous fat transfer procedures more reliable and efficient for treatment of articular cartilage defects.

Effect of osteochondral graft orientation in a biotribological test system

Autologous osteochondral transplantation (AOT) utilizing autografts is a widely used technique for the treatment of small-to-medium cartilage defects occurring in knee and ankle joints. The application of viable cartilage and bone ensures proper integration, early weight bearing, as well as restoration of biomechanical and biotribological properties. However, alignment of the autografts onto the defect site remains a pivotal aspect of reinstating the properties of the joint toward successful autograft integration. This is the first study to perform tests with different orientations of osteochondral grafts in a cartilage-on-cartilage test system. The objective was to estimate if there are differences between aligned and 90°-rotated grafts concerning molecular biological and biomechanical parameters. Tissue viability, assessed by XTT assay indicated lower metabolic activity in tested osteochondral grafts (aligned, p = 0.0148 and 90°-rotated, p = 0.0760) in favor of a higher anabolic gene expression (aligned, p = 0.0030 and 90°-rotated, 0.0027). Tissue structure was evaluated by Safranin O histology and microscopic images of the surface. Aligned and 90°-rotated grafts revealed no apparent differences between proteoglycan content or cracks and fissures on the cartilage surface. Test medium analyzed after tribological tests for their sulfated glycosaminoglycan content revealed no differences (p = 0.3282). During the tests, both the friction coefficient and the relative displacement between the two cartilage surfaces were measured, with no significant difference in both parameters (COF, p = 0.2232 and relative displacement, p = 0.3185). From the methods we deployed, this study can infer that there are no differences between aligned and 90°-rotated osteochondral grafts after tribological tests in the used ex vivo tissue model. © 2019 The Authors. Journal of Orthopaedic Research® Published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res.

A Scaffold-Free Allogeneic Construct From Adipose-Derived Stem Cells Regenerates an Osteochondral Defect in a Rabbit Model

PURPOSE

To determine whether an osteochondral defect could be healed histologically by implanting allogeneic 3-dimensionally formed adipose-derived stem cells (ADSCs) in a rabbit model.

METHODS

Thirty Japanese white rabbits (aged 15-17 weeks) were assigned to 1 of 2 groups. An osteochondral defect (diameter, 4.8 mm; depth, 3 mm) was created in the trochlear groove of the knee using a drill. The defects were left empty in the control group and were filled with cylindrical plugs of allogeneic ADSCs extracted from adipose tissue in the experimental group. Macroscopic scoring, histologic scoring, and immunohistologic stainability of type II collagen were evaluated at 4, 8, and 12 weeks postoperatively.

RESULTS

The macroscopic scores of the healing tissue in the experimental group were significantly greater than those in the control group at 12 weeks (P = .031). Histologically, safranin O staining was noted at 4 weeks and increased gradually over time in the experimental group. The modified International Cartilage Repair Society histologic score in the experimental group was significantly higher than that in the controls at 8 and 12 weeks (14 vs 9 at 8 weeks [P = .008], 18 vs 10 at 12 weeks [P = .007]). The implanted tissue was positive for type II collagen, and stainability increased gradually over time.

CONCLUSIONS

The 3-dimensional scaffold-free allogeneic ADSCs implanted into the osteochondral defect survived, adhered to the defect, increased the stainability of type II collagen gradually over time, and promoted histologic healing in a rabbit model.

CLINICAL RELEVANCE

ADSC implantation designed to promote osteochondral healing may play an important role in osteochondral healing.

Randomized Study of Long-term (15-17 Years) Outcome After Microfracture Versus Mosaicplasty in Knee Articular Cartilage Defects

BACKGROUND

Few comparative randomized long-term studies on microfracture versus mosaicplasty have been published, and only 2 studies reported a follow-up of 10 years. Hypothesis/Purpose: The purpose was to compare the clinical outcome of microfracture versus mosaicplasty/osteochondral autograft transfer in symptomatic cartilage lesions. The null hypothesis was that the outcome was not statistically different at any point of time.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

Forty patients with articular cartilage defects were randomized to undergo cartilage repair by either microfracture (n = 20) or mosaicplasty (n = 20). Inclusion criteria were as follows: age 18 to 50 years at the time of surgery, 1 or 2 symptomatic focal full-thickness articular chondral defects on the femoral condyles or trochlea, and size 2 to 6 cm². The main outcome variable was the Lysholm knee score recorded before the surgery and at 12 months, median 5 years, median 10 years, and minimum 15 years after the surgery.

RESULTS

Forty patients were included in the study (28 men, 12 women; median age, 32 years; range, 18-48 years). Defects with a median size of 3.5 cm² (range, 2-5 cm²) were treated. A significant increase in the Lysholm score was seen for all subjects- from a mean 53 (SD, 16) at baseline to 69 (SD, 21) at the minimum 15-year follow-up ( P = .001). The mean Lysholm score was significantly higher in the mosaicplasty group than the microfracture group at 12 months, median 5 years, median 10 years, and minimum 15 years: 77 (SD, 17) versus 61 (SD, 22), respectively ( P = .01), at the last follow-up. At all follow-up time points, the difference in mean Lysholm score was clinically significant (>10 points).

CONCLUSION

At short, medium, and long term (minimum 15 years), mosaicplasty results in a better, clinically relevant outcome than microfracture in articular cartilage defects (2-5 cm²) of the distal femur of the knee in patients aged 18 to 50 years.

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.

Osteochondral Autologous Transplantation

Osteochondral autologous transplantation (OAT) is a treatment strategy for small and medium sized focal articular cartilage defects in the knee. This article reviews the indications, surgical techniques, outcomes, and limitations of OAT for the management of symptomatic chondral and osteochondral lesions in the knee joint.