Outcomes of microfracture for traumatic chondral defects of the knee: average 11-year follow-up

Articular Cartilage Repair in the Knee: Postoperative Imaging

Diagnostic and therapeutic advancements have improved clinical outcomes for patients with focal chondral injuries of the knee. An increased number and complexity of surgical treatment options have, in turn, resulted in a commensurate proliferation of patients requiring postoperative evaluation and management. In addition to patient-reported clinical outcomes, magnetic resonance imaging (MRI) offers clinicians with noninvasive, objective data to assist with postoperative clinical decision making. However, successful MRI interpretation in this setting is clinically challenging; it relies upon an understanding of the evolving and procedure-specific nature of normal postoperative imaging. Moreover, further research is required to better elucidate the correlation between MRI findings and long-term clinical outcomes. This article focuses on how specific morphologic features identified on MRI can be utilized to evaluate patients following the most commonly performed cartilage repair surgeries of the knee.

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.

Exercise as an Adjuvant to Cartilage Regeneration Therapy

This article provides a brief review of the pathophysiology of osteoarthritis and the ontogeny of chondrocytes and details how physical exercise improves the health of osteoarthritic joints and enhances the potential of autologous chondrocyte implants, matrix-induced autologous chondrocyte implants, and mesenchymal stem cell implants for the successful treatment of damaged articular cartilage and subchondral bone. In response to exercise, articular chondrocytes increase their production of glycosaminoglycans, bone morphogenic proteins, and anti-inflammatory cytokines and decrease their production of proinflammatory cytokines and matrix-degrading metalloproteinases. These changes are associated with improvements in cartilage organization and reductions in cartilage degeneration. Studies in humans indicate that exercise enhances joint recruitment of bone marrow-derived mesenchymal stem cells and upregulates their expression of osteogenic and chondrogenic genes, osteogenic microRNAs, and osteogenic growth factors. Rodent experiments demonstrate that exercise enhances the osteogenic potential of bone marrow-derived mesenchymal stem cells while diminishing their adipogenic potential, and that exercise done after stem cell implantation may benefit stem cell transplant viability. Physical exercise also exerts a beneficial effect on the skeletal system by decreasing immune cell production of osteoclastogenic cytokines interleukin-1β, tumor necrosis factor-α, and interferon-γ, while increasing their production of antiosteoclastogenic cytokines interleukin-10 and transforming growth factor-β. In conclusion, physical exercise done both by bone marrow-derived mesenchymal stem cell donors and recipients and by autologous chondrocyte donor recipients may improve the outcome of osteochondral regeneration therapy and improve skeletal health by downregulating osteoclastogenic cytokine production and upregulating antiosteoclastogenic cytokine production by circulating immune cells.

A longterm prospective follow-up study of resurfacing miniprosthesis suitable for patients above sixtyfive years with localized cartilage lesions or early osteoarthritis in the knee

Purpose

The aim of the study was to investigate the long-term outcomes of the Focal Femoral Condyle Resurfacing Prosthesis for treatment of localized cartilage lesion in patients > 65 years.

Methods

This was a prospective case series study. Non-reopererated patients initially treated with resurfacing condylar miniprothesis (HemiCAP/UniCAP) were evaluated clinically and radiographically at 7–10 years follow-up (mean 9 years). The clinical examination included the Knee Society Score (KSS) and Visual Analogue Scale (VAS) pain score and EQ5D. The radiographic examination included the Kellgren-Lawrence (KL) grade for investigate of OA progression. A comparison analysis of the preoperative and follow-up subjective outcome data and a Kaplan-Meier implant survival analysis were performed.

Results

Twenty-three patients were included in the study (9 HemiCAP and 14 UniCAP). There were seven revisions (one HemiCap and six UniCap respectively) (30%) and three patients had died. Follow-up examinations were performed on 10 patients. When comparing follow-up with the preoperative state, there were significant increases in the KSS objective (50.0 ± 8.3) vs. 90.0 ± 6.3)) and KSS function (45.0 ± 11.7) vs. 85.0 ± 4.7)) scores, a decrease in the pain VAS score (7.0 ± 0.9) vs. (4.0 ± 1.9)). Radiographic evaluation demonstrated increase in osteoarthritis development with a KL medial score (2.0 ± 0.6) and KL lateral score (1.4 ± 0.6) vs. (2.0 ± 0.9)).The EQ5D-score was 86 ± 8.4 and patients Health-score was 85 ± 18).

Conclusions

Resurfacing implant treatment for early OA in patients above 65 years can require revision to knee arthroplasty in 30% of patients. But in patients that are not revised long-term improvements in subjective clinical outcome was demonstrated. This suggests that even elderly patients with isolated cartilage lesions or early OA might benefit from the limited invasive resurfacing implant treatment.

Level of evidence

IV

Clinical and Radiographic Outcomes After Fixation of Chondral Fragments of the Knee in 6 Adolescents Using Autologous Bone Pegs

Background:

Little is known regarding the optimal treatment for displaced, purely chondral fragments in the knee.

Purpose:

To report the clinical and radiographic outcomes of chondral fragment fixation in adolescents through use of autologous bone pegs.

Study Design:

Case series; Level of evidence, 4.

Methods:

This retrospective, single-center study evaluated 6 patients (mean age, 12.9 years) who underwent fixation of chondral fragments (no visualized bone attached) using autologous bone pegs (mean postoperative follow-up, 5.2 years; range, 1.4-10.9 years). The causes were trauma (n = 5) and osteochondritis dissecans (n = 1). Lesions were located in the trochlear groove (lateral, n = 3; medial, n = 2) or posterior part of the lateral femoral condyle (n = 1). The mean lesion size was 3.8 cm² (range, 0.8-9.0 cm²). Patients were evaluated via physical examination and magnetic resonance imaging (MRI) using magnetic resonance observation of cartilage repair tissue scores.

Results:

In total, 5 patients successfully returned to sports without restrictions at a mean of 7 months (range, 6-8 months) postoperatively. At the latest follow-up, these 5 patients had full range of motion and no joint effusion. The mean magnetic resonance observation of cartilage repair tissue score was 85 (range, 70-95) at a mean duration of 3 years (range, 1-5 years). One patient experienced failure at 1.3 years postoperatively after a traumatic injury and subsequently underwent removal of the fixed fragment and a drilling procedure.

Conclusion:

In most adolescents, fixation of chondral fragments with no visualized bony portion using autologous bone pegs provided a satisfactory success rate and good healing of cartilage tissue confirmed on MRI scans.

Clinical Application of the Basic Science of Articular Cartilage Pathology and Treatment

The joint is an organ with each tissue playing critical roles in health and disease. Intact articular cartilage is an exquisite tissue that withstands incredible biologic and biomechanical demands in allowing movement and function, which is why hyaline cartilage must be maintained within a very narrow range of biochemical composition and morphologic architecture to meet demands while maintaining health and integrity. Unfortunately, insult, injury, and/or aging can initiate a cascade of events that result in erosion, degradation, and loss of articular cartilage such that joint pain and dysfunction ensue. Importantly, articular cartilage pathology affects the health of the entire joint and therefore should not be considered or addressed in isolation. Treating articular cartilage lesions is challenging because left alone, the tissue is incapable of regeneration or highly functional and durable repair. Nonoperative treatments can alleviate symptoms associated with cartilage pathology but are not curative or lasting. Current surgical treatments range from stimulation of intrinsic repair to whole-surface and whole-joint restoration. Unfortunately, there is a relative paucity of prospective, randomized controlled, or well-designed cohort-based clinical trials with respect to cartilage repair and restoration surgeries, such that there is a gap in knowledge that must be addressed to determine optimal treatment strategies for this ubiquitous problem in orthopedic health care. This review article discusses the basic science rationale and principles that influence pathology, symptoms, treatment algorithms, and outcomes associated with articular cartilage defects in the knee.

Autologous matrix-induced chondrogenesis and bone marrow aspirate concentrate compared with microfracture for arthroscopic treatment of femoroacetabular impingement and chondral lesions of the hip: bridging the osteoarthritis gap and facilitating enhanced recovery

In an attempt to bridge the osteoarthritis (OA) gap, this study compared biological reconstruction with traditional microfracture (MF) techniques in patients with femoroacetabular impingement and focal cartilage defects. Cohorts of two groups were investigated; age, gender and Tonnis grade matched comparison for outcomes between MF and newer biological reconstruction techniques hip arthroscopy surgery using autologous matrix-induced chondrogenesis and bone marrow aspirate combination. Outcomes investigated were pre-op and post-op mean iHOT-12 scores up to 18 months after surgery with a Kaplan–Meier survivorship analysis. Of 111 patients, 46 patients underwent MF and 65 biological reconstruction hip arthroscopy including cam/pincer osteoplasty and labral repair surgery. Age range was 20–69, mean age 45 years for both groups, Tonnis grading was as follows: Grade 0: 26% versus 30%, Grade 1: 52% versus 47% and Grade 2: 22% versus 23% in MF and biological reconstruction groups, respectively. The mean post-operative iHOT-12 score differences between MF and biological reconstruction were significant at 1-year minimum follow-up (P = 0.01, SD 2.8). Biological reconstruction allowed for an enhanced recovery protocol. The MF group had a 67.4% survivorship for conversion to hip replacement at 18 months (32.6% failure rate for any reason) and biological reconstruction had 100% survivorship at 18 months post-operatively with no failures for any reason. This study provides further support to the evidence base for biological reconstructive techniques as superior to MF in combination with joint preservation arthroscopic surgery, even in the face of focal cartilage defects and offers both surgeons and patients a potential bridging of the OA gap.

Enhanced microfracture using acellular scaffolds improves results after treatment of symptomatic focal grade III/IV knee cartilage lesions but current clinical evidence does not allow unequivocal recommendation

PURPOSE

To systematically analyse post-operative outcomes following enhanced microfracture procedures in focal cartilage injuries of the knee.

METHODS

Database searches were conducted in PubMed, EMBASE and Cochrane Library databases up to 30 November 2018, for clinical studies in humans that assessed surgical outcomes of enhanced microfracture procedures in focal cartilage injuries of the knee. The clinical, functional and imaging outcomes were assessed and summarized. The MINORS scale was used to assess the methodological quality of the studies included.

RESULTS

Ten studies were included comprising a total of 331 patients (mean age of 37.0 ± 5.5 years, body mass 25.2 ± 1.7 kg m², 56% male and 42% left knee), 278 femoral condyle chondral defects (147 medial, 35 lateral and 78 undefined) and 43 chondral defects distributed by the tibial plateau, patella and femoral trochlea. The chondral defects were mostly Outerbridge grade III or IV and the mean defect size was 3.2 ± 0.6 cm². Studies consistently demonstrated significant improvement in the patient-reported outcome measures from baseline to final follow-up. Overall, imaging outcomes showed inconsistent results. Treatment-related adverse events were poorly reported.

CONCLUSION

Enhanced microfracture techniques significantly result in improved patient-reported outcome measures over the MCID, but provide inconsistent imaging results. Current clinical evidence does not allow for unequivocal recommendation of enhanced microfracture to treat symptomatic focal grade III/IV knee cartilage lesions.

LEVEL OF EVIDENCE

IV.

Bipolar Osteochondral Allograft Transplantation of the Patella and Trochlea

OBJECTIVE

To evaluate clinical, functional, and radiographic outcomes of patients who underwent bipolar osteochondral allograft transplantation (OCAT) of the patellofemoral joint (PFJ).

DESIGN

Prospectively collected data on 18 knees who underwent fresh osteochondral allograft transplantation of the patella and trochlea by a single surgeon were reviewed. Inclusion criteria were: high-grade chondral lesions of PFJ (5 knees), or recurrent patella dislocations with trochlear dysplasia and chondral injury to the patella and/or trochlea (13 knees). Functional scores were obtained preoperatively and at follow-up appointments included Knee injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee (IKDC), Oxford, Cincinnati, Tenger-Lysholm, visual analogue scale (VAS)-pain, and Single Assessment Numeric Evaluation (SANE). Grafts were also evaluated using Osteochondral Allograft MRI Scoring System (OCAMRISS).

RESULTS

Three patients were lost to follow-up, leaving 4 knees in group 1, and 11 knees in group 2. Average age was 28.9 years (range 16-52 years). The average follow-up was 33.2 months (range 12-64 months). There was significant improvement of KOOS (from 38.7 to 83.1), IKDC (from 28.2 to 76.6), Tegner-Lysholm (from 38.3 to 88.3), Oxford (from 22.7 to 42.9), Cincinnati (from 35.1 to 83.6), VAS (from 71 to 17.9.), and SANE (from 43.3 to 83) (P < 0.0001). The OCAMRISS score for patella was 2.23 and for trochlea 4.69. There were no revisions or conversions to arthroplasty.

CONCLUSION

Bipolar OCAT of the patella and trochlea provide significant improvement in functional outcomes, relief from pain, activity level, and prevent recurrent instability.

Differential Production of Cartilage ECM in 3D Agarose Constructs by Equine Articular Cartilage Progenitor Cells and Mesenchymal Stromal Cells

Identification of articular cartilage progenitor cells (ACPCs) has opened up new opportunities for cartilage repair. These cells may be used as alternatives for or in combination with mesenchymal stromal cells (MSCs) in cartilage engineering. However, their potential needs to be further investigated, since only a few studies have compared ACPCs and MSCs when cultured in hydrogels. Therefore, in this study, we compared chondrogenic differentiation of equine ACPCs and MSCs in agarose constructs as monocultures and as zonally layered co-cultures under both normoxic and hypoxic conditions. ACPCs and MSCs exhibited distinctly differential production of the cartilaginous extracellular matrix (ECM). For ACPC constructs, markedly higher glycosaminoglycan (GAG) contents were determined by histological and quantitative biochemical evaluation, both in normoxia and hypoxia. Differential GAG production was also reflected in layered co-culture constructs. For both cell types, similar staining for type II collagen was detected. However, distinctly weaker staining for undesired type I collagen was observed in the ACPC constructs. For ACPCs, only very low alkaline phosphatase (ALP) activity, a marker of terminal differentiation, was determined, in stark contrast to what was found for MSCs. This study underscores the potential of ACPCs as a promising cell source for cartilage engineering.

Current hip cartilage regeneration/repair modalities: a scoping review of biologics and surgery

PURPOSE

The rapidly growing and emerging nature of biologics have made indications for regenerative and reparative hip therapies ever changing, with at times only early-stage evidence for their use. The purpose of this study was to review and summarize the currently available data on the management of hip cartilage injuries and osteoarthritis.

METHODS

A scoping review of the available scientific literature for hip biologics was performed, with available evidence for hyaluronic acid (HA), platelet rich plasma (PRP), stem/stromal cells, microfracture, mosaicplasty, osteochondral allograft, and cell-based therapies investigated.

RESULTS

To date, there exist better guidelines and further consensus concerning knee joint biologic treatments than the hip due to a greater number of studies as well as the more recent emergence of hip preservation approaches. However, increasing evidence is available for the selective implementation of biologics on an individualized basis with attention to lesion size and location.

CONCLUSION

Orthopedic surgeons are at an exciting crossroads in medicine, where hip biologic therapies are evolving and increasingly available. Timetested interventions such as arthroplasty have shown good results and still have a major role to play but newer, regenerative approaches have the potential to effectively delay or reduce the requirement for such invasive procedures.

Cartilage repair using stem cells & biomaterials: advancement from bench to bedside

Osteoarthritis (OA) involves gradual destruction of articular cartilagemanifested by pain, stiffness of joints, and impaired movement especially in knees and hips. Non-vascularity of this tissue hinders its self-regenerative capacity and thus, the application of reparative or restorative modalities becomes imperative in OA treatment. In recent years, stem cell-based therapies have been explored as potential modalities for addressing OA complications. While mesenchymal stem cells (MSCs) hold immense promise, the recapitulation of native articular cartilage usingMSCs remains elusive. In this review, we have highlighted the chondrogenic potential of MSCs, factors guiding in vitro chondrogenic differentiation, biomaterials available for cartilage repair, their current market status, and the outcomes of major clinical trials. Our search on ClinicalTrials.gov using terms "stem cell" and "osteoarthritis" yielded 83 results. An analysis of the 29 trials that have been completed revealed differences in source of MSCs (bone marrow, adipose tissue, umbilical cord etc.), cell type (autologous or allogenic), and dose administered. Moreover, only 02 out of 29 studies have reported the use of matrix for cartilage repair. From future perspective, aconsensus on choice of cells, differentiation inducers, biomaterials, and clinical settings might pave a way for concocting robust strategies to improve the clinical applicability of biomimetic neocartilage constructs.

Clinical Outcomes of an All-Arthroscopic Technique for Single-Stage Autologous Matrix-Induced Chondrogenesis in the Treatment of Articular Cartilage Lesions of the Knee

Purpose

The purpose of this study was to determine the clinical efficacy of an all-arthroscopic approach to autologous matrix-induced chondrogenesis (AMIC) for patients with articular cartilage lesions of the knee joint. We hypothesize that an all-arthroscopic, single-stage AMIC using a hyaluron-based cell-free scaffold improves the postoperative clinical scores for patients with isolated articular cartilage lesions of the knee in the early follow-up period.

Methods

All patients with focal osteochondral lesions of the knee treated with AMIC at our institution from November 2013 to January 2018 were included for analysis. Demographic information, baseline clinical characteristics, perioperative imaging, and follow-up International Knee Documentation Committee (IKDC) scores at 6 and 24 months postoperatively were collected. One-way analysis of variance (ANOVA) with a Bonferroni correction was used to assess for improvement before and after surgery, with statistical significance defined as p < .05.

Results

A total of 22 patients met the inclusion criteria and were analyzed for this study. Articular cartilage lesions were most commonly found at the center of the medial and lateral femoral condyles. Statistically significant improvements in IKDC scores were seen at the 6- and 24-month follow-up periods (p < .05).

Conclusion

An all-arthroscopic technique for single-stage autologous matrix-induced chondrogenesis demonstrates significant early clinical improvement for the treatment of articular cartilage lesions of the knee.

Level of Evidence

4

The effect of distance between holes on the structural stability of subchondral bone in microfracture surgery: a finite element model study

Background

Microfracture is a surgical technique that involves creating multiple holes of 3–4 mm depth in the subchondral bone to recruit stem cells in the bone marrow to the lesion, inducing fibrocartilage repair and knee cartilage regeneration. Recently, it has been reported that increasing the exposed area of the lower cartilaginous bone (drilling a lot of holes) increases the outflow of stem cells, which is expected to affect the physical properties of the subchondral bone when the exposed area is large. The purpose of this study was to analyse the effect of the distance between the holes in the microfracture procedure on the structural stability of the osteochondral bone using a finite element method.

Methods

In this study, lateral aspects of the femoral knee, which were removed during total knee arthroplasty were photographed using microtomography. The model was implemented using a solitary walks program, which is a three-dimensional simplified geometric representation based on the basic microtomography data. A microfracture model was created by drilling 4 mm-deep holes at 1, 1.5, 2, 2.5, 3, 4, and 5 mm intervals in a simplified three-dimensional (3D) geometric femoral model. The structural stability of these models was analysed with the ABAQUS program. We compared the finite element model (FEM) based on the microtomography image and the simplified geometric finite element model.

Results

Von Mises stress of the subchondral bone plate barely increased, even when the distance between holes was set to 1 mm. Altering the distance between the holes had little impact on the structural stability of the subchondral bone plate. Safety factors were all below 1.

Conclusions

Although we did not confirm an optimal distance between holes, this study does provide reference data and an epidemiological basis for determining the optimal distance between the holes used in the microfracture procedure.

Are Weightbearing Restrictions Required After Microfracture for Isolated Chondral Lesions of the Knee? A Review of the Basic Science and Clinical Literature

CONTEXT

A strict rehabilitation protocol is traditionally followed after microfracture, including weightbearing restrictions for 2 to 6 weeks. However, such restrictions pose significant disability, especially in a patient population that is younger and more active.

EVIDENCE ACQUISITION

An extensive literature review was performed through PubMed and Google Scholar of all studies through December 2018 related to microfracture, including biomechanical, basic science, and clinical studies. For inclusion, clinical studies had to report weightbearing status and outcomes with a minimum 12-month follow-up.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 3.

RESULTS

Review of biomechanical and biology studies suggest new forming repair tissue is protected from shear forces of knee joint loading by the cartilaginous margins of the defect. This margin acts as a shoulder to maintain axial height and allow for tissue remodeling up to at least 12 months after surgery, well beyond current weight bearing restriction trends. A retrospective case-control study showed that weightbearing status postoperatively had no effect on clinical outcomes in patients who underwent microfracture for small chondral (<2 mm²) defects. In fact, 1 survey showed that many orthopaedic surgeons currently do not restrict weightbearing after microfracture.

CONCLUSION

This clinical literature review suggests that weightbearing restrictions may not be required after microfracture for isolated tibiofemoral chondral lesions of the knee.

STRENGTH OF RECOMMENDATION TAXONOMY

C.

Biological perspectives and current biofabrication strategies in osteochondral tissue engineering

Articular cartilage and the underlying subchondral bone are crucial in human movement and when damaged through disease or trauma impacts severely on quality of life. Cartilage has a limited regenerative capacity due to its avascular composition and current therapeutic interventions have limited efficacy. With a rapidly ageing population globally, the numbers of patients requiring therapy for osteochondral disorders is rising, leading to increasing pressures on healthcare systems. Research into novel therapies using tissue engineering has become a priority. However, rational design of biomimetic and clinically effective tissue constructs requires basic understanding of osteochondral biological composition, structure, and mechanical properties. Furthermore, consideration of material design, scaffold architecture, and biofabrication strategies, is needed to assist in the development of tissue engineering therapies enabling successful translation into the clinical arena. This review provides a starting point for any researcher investigating tissue engineering for osteochondral applications. An overview of biological properties of osteochondral tissue, current clinical practices, the role of tissue engineering and biofabrication, and key challenges associated with new treatments is provided. Developing precisely engineered tissue constructs with mechanical and phenotypic stability is the goal. Future work should focus on multi-stimulatory environments, long-term studies to determine phenotypic alterations and tissue formation, and the development of novel bioreactor systems that can more accurately resemble the in vivo environment.

Temporal TGF-β Supergene Family Signalling Cues Modulating Tissue Morphogenesis: Chondrogenesis within a Muscle Tissue Model?

Temporal translational signalling cues modulate all forms of tissue morphogenesis. However, if the rules to obtain specific tissues rely upon specific ligands to be active or inactive, does this mean we can engineer any tissue from another? The present study focused on the temporal effect of “multiple” morphogen interactions on muscle tissue to figure out if chondrogenesis could be induced, opening up the way for new tissue models or therapies. Gene expression and histomorphometrical analysis of muscle tissue exposed to rat bone morphogenic protein 2 (rBMP-2), rat transforming growth factor beta 3 (rTGF-β₃₎, and/or rBMP-7, including different combinations applied briefly for 48 h or continuously for 30 days, revealed that a continuous rBMP-2 stimulation seems to be critical to initiate a chondrogenesis response that was limited to the first seven days of culture, but only in the absence of rBMP-7 and/or rTGF-β₃. After day 7, unknown modulatory effects retard rBMP-2s’ effect where only through the paired-up addition of rBMP-7 and/or rTGF-β₃ a chondrogenesis-like reaction seemed to be maintained. This new tissue model, whilst still very crude in its design, is a world-first attempt to better understand how multiple morphogens affect tissue morphogenesis with time, with our goal being to one day predict the chronological order of what signals have to be applied, when, for how long, and with which other signals to induce and maintain a desired tissue morphogenesis.

Autologous collagen-induced chondrogenesis versus microfracture for chondral defects of the knee: Surgical technique and 2-year comparison outcome study

Objective

Osteochondral lesions of the knee affect patients from all age groups with arthroscopic microfracture being the current gold standard of treatment of such lesions. Autologous collagen-induced chondrogenesis (ACIC) is a novel procedure that has recently been gaining popularity. This study aims to compare the 6 and 24 month post-operative outcomes between patients undergoing microfracture only and microfracture with ACIC.

Methods

Patients from both groups were assessed pre-operatively, at 6 and 24 months post-operatively for functional outcomes using SF-36 and IKDC scoring (International Knee Documentation Committee Subjective Knee Form).

Results

Both groups showed improved SF-36 and IKDC scores at 6 and 24 months, however patients who underwent ACIC showed better SF-36 mental component and IKDC scores 24 months after surgery.

Conclusion

This demonstrates that ACIC is an effective, single-stage, joint-preserving procedure which is comparable, if not better, in treating chondral defects.

Journal Article Titles Impact Their Citation Rates

A journal article's title gives authors one chance to make a first impression and communicate succinctly the findings from their important research. The goal of a research article rests in disseminating information. Both authors and academic journals benefit from increasing the number of times an investigation is cited. A scientific manuscript title accurately summarizes the research using key words that can be identified with search engines. This review aims to condense evidence-based research to improve a scientific manuscript title for both clarity and impact.

Better Clinicoradiological Results of BST-CarGel Treatment in Cartilage Repair Compared With Microfracture in Acetabular Chondral Defects at 2 Years

BACKGROUND

BST-CarGel (CarGel) is an injectable chitosan scaffold that is mixed with fresh, autologous blood and injected into the site of microfracture (MF) to physically stabilize clots and enhance cartilage repair.

PURPOSE

To evaluate short-term clinicoradiological outcomes of patients treated arthroscopically for acetabular chondral defects with CarGel in conjunction with MF compared with those treated with MF alone.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

All patients who underwent hip arthroscopy and received MF with or without CarGel for acetabular chondral defects between 2014 and 2018 with a minimum 2-year clinicoradiological follow-up were included. Intraoperative details, postoperative complications, and clinical outcome scores, including the international Hip Outcome Tool-33 (iHOT-33), Hip Outcome Score (HOS)-Activities of Daily Living (HOS-ADL), and Hip Outcome Score-Sports Profile, were analyzed. Serial plain radiographs were assessed independently by 2 blinded observers. A survival analysis was performed to identify the number of cases converted to total hip arthroplasty (THA) in both groups, which was correlated with the cartilage defect size at the time of surgery.

RESULTS

Eighty patients (54 CarGel and 26 MF) were evaluated, including 56 men (70%) and 48 right hips (60%). Three patients were lost to follow-up. There were no major adverse events in either group. The average defect size was 3.63 and 4.97 cm² in MF and CarGel, respectively (P = .002). There was a statistically significant improvement in iHOT-33 (from 43.24 to 60.17 in MF and from 41.13 to 58.39 in CarGel) and HOS-ADL (from 62.25 to 76.75 in MF and from 44.69 to 79.16 in CarGel) scores. There was no difference between the 2 groups in the outcome scores after adjusting for covariates. Survival analysis showed 34.6% of MF cases and 5.9% of CarGel cases were converted to THA (P = .001). The mean defect size of the failure group was higher in CarGel than in MF (8.83 and 3.72 cm², respectively). Mean joint space reduction was 1.41 mm in MF and 0.19 mm in CarGel (P < .001).

CONCLUSION

Two-year clinicoradiological results were promising in these lesions that are difficult to treat. Arthroscopic treatment of chondral acetabular defects with CarGel demonstrated a significant decrease in progressive loss of joint space and conversion to THA compared with MF as an isolated procedure.

Effects of Micronized Cartilage Matrix on Cartilage Repair in Osteochondral Lesions of the Talus

BACKGROUND

The repair of osteochondral lesions remains a challenge due to its poor vascularity and limited healing potential. Micronized cartilage matrix (MCM) is dehydrated, decellularized, micronized allogeneic cartilage matrix that contains the components of native articular tissue and is hypothesized to serve as a scaffold for the formation of hyaline-like tissue. Our objective was to demonstrate in vitro that the use of MCM combined with mesenchymal stem cells (MSCs) can lead to the formation of hyaline-like cartilage tissue in a single-stage treatment model.

DESIGN

In group 1 (no wash), 250 µL MCM was reconstituted in 150 µL Dulbecco's phosphate-buffered saline (DPBS) for 5 minutes. Group 2 (saline wash) included 250 µL MCM washed in 20 mL DPBS for 30 minutes, then aspirated to remove all DPBS and reconstituted in 150 µL DPBS. Group 3 (serum wash): 250µL MCM washed in 20 mL DPBS for 30 minutes, then aspirated and reconstituted in 150 µL fetal bovine serum. Each group was then added to 50 µL solution of MSC suspended in DPBS at a concentration of 1.2 × 10⁶ cells/350 µL. After 3 weeks, the defects were extracted and sectioned to perform viability and histologic analyses.

RESULTS

Stem cells without rehydration of the MCM showed almost no viability whereas near complete cell viability was seen after rehydration with serum or saline solution, ultimately leading to chondrogenic differentiation and adhesion to the MCM particles.

CONCLUSION

We have shown in this proof-of-concept in vitro study that MCM can serve as a scaffold for the growth of cartilage tissue for the treatment of osteochondral lesions.

Osteochondral Regeneration Using Adipose Tissue-Derived Mesenchymal Stem Cells

Osteoarthritis (OA) is a major joint disease that promotes locomotor deficiency during the middle- to old-age, with the associated disability potentially decreasing quality of life. Recently, surgical strategies to reconstruct both articular cartilage and subchondral bone for OA have been diligently investigated for restoring joint structure and function. Adipose tissue-derived mesenchymal stem cells (AT-MSCs), which maintain pluripotency and self-proliferation ability, have recently received attention as a useful tool to regenerate osteocartilage for OA. In this review, several studies were described related to AT-MSC spheroids, with scaffold and scaffold-free three-dimensional (3D) constructs produced using “mold” or “Kenzan” methods for osteochondral regeneration. First, several examples of articular cartilage regeneration using AT-MSCs were introduced. Second, studies of osteochondral regeneration (not only cartilage but also subchondral bone) using AT-MSCs were described. Third, examples were presented wherein spheroids were produced using AT-MSCs for cartilage regeneration. Fourth, osteochondral regeneration following autologous implantation of AT-MSC scaffold-free 3D constructs, fabricated using the “mold” or “Kenzan” method, was considered. Finally, prospects of osteochondral regeneration by scaffold-free 3D constructs using AT-MSC spheroids were discussed.

Effects of focal metallic implants on opposing cartilage - an in-vitro study with an abrasion test machine

Background

For focal cartilage defects, biological repair might be ineffective in patients over 45 years. A focal metallic implant (FMI) (Hemi-CAP Arthrosurface Inc., Franklin, MA, USA) was designed to reduce symptoms. The aim of this study was to evaluate the effects of a FMI on the opposing tibial cartilage in a biomechanical set-up. It is hypothesized that a FMI would not damage the opposing cartilage under physiological loading conditions.

Methods

An abrasion machine was used to test the effects of cyclic loading on osteochondral plugs. The machine applied a compressive load of 33 N and sheared the samples 10 mm in the anteroposterior direction by 1 Hz. Tibial osteochondral plugs from porcine knees were placed in opposition to a FMI and cycled for 1 or 6 h. After testing each plug was fixed, stained and evaluated for cartilage damage.

Results

After 1 h of loading (n = 6), none of the osteochondral plugs showed histologic signs of degradation. After 6 h of loading (n = 6) three samples had histologic signs of injury in the tangential zone (grade 1) and one had signs of injury in the transitional and deep zones (grade 2). Exploration for 6 h resulted in significant more cartilage damage compared to the shorter exploration time (p = 0.06). However, no significant difference between saline and hyaluronic acid was evident (p = 0.55).

Conclusion

Under physiologic loading conditions, contact with a FMI leads to cartilage damage in the opposing articular cartilage in six hours. In clinical practice, a thorough analysis of pre-existing defects on the opposing cartilage is recommended when FMI is considered.

Clinical outcome after treatment of single and multiple cartilage defects by autologous matrix-induced chondrogenesis

PURPOSE

Characterized cartilage lesions have a distinct impact on postoperative clinical outcome, which is still being evaluated. The purpose of this study was to assess the postoperative clinical outcome of autologous matrix-induced chondrogenesis (AMIC) for characterized cartilage lesions.

METHODS

Fifteen patients with articular cartilage (AC) defects of the knee were included in the study. AC defects were characterized intraoperatively by International Cartilage Repair Society score. Grade III-IV AC lesions were treated with AMIC; grade I-II lesions were left untreated. Patients were divided into subgroups and clinically evaluated by subjective autologous matrix-induced chondrogenesis (IKDC) and Tegner scores at median follow-up of 4.5 years.

RESULTS

Twenty-eight AC defects were diagnosed (1.9/patient). Multiple subgroup had larger diagnosed (7 ± 2.3 cm², p = 0.022) and untreated (3.1 ± 2.3 cm², p = 0.012) lesion areas than the single subgroup. Partly treated subgroup had larger untreated defect areas (3.6±2.3 cm², p = 0.025) than the Treated subgroup. Average subjective IKDC values of total group and individual subgroups improved significantly at follow-up. More patients restored their previous activity levels ( p = 0.026) and had higher incremental subjective IKDC scores ( p = 0.014) in the single subgroup than the multiple subgroup. Diagnosed defect size negatively correlated to subjective IKDC incremental ( r = -0.624, p = 0.023) and postoperative scores ( r = -0.545, p = 0.054) in total group.

CONCLUSIONS

AMIC can have a clinically relevant outcome for patients with single or multiple knee AC lesions; however, clinical outcome is superior in patients with a single defect per knee. Patients with single defects returned to previous physical activity levels significantly faster than patients with multiple defects. Diagnosed AC defect areas negatively correlate to clinical improvement at follow-up.

Autologous osteochondral transplantation method of treatment for patellar osteochondral lesions

PURPOSE

This study evaluated the functional and clinical outcomes of the subjects with symptomatic osteochondral lesions on articular surface of patella, who were treated with autologous osteochondral transplantation (AOT) method.

STUDY PLAN

AOT method was applied for the treatment of 14 subjects (eight men and six women; mean age 29.7 years; range 19-49 years) with symptomatic patellar osteochondral lesions between March 2008 and April 2013. After a mean follow-up period of 3.7 years (range 32-80 months), pre- and postoperative clinical and functional evaluations of the patients were performed using Visual Pain Scale (VPS), Lysholm Knee Scoring Scale, and Kujala Anterior Knee Pain Scale. Wilcoxon test was used for statistical evaluation of pre- and postoperative outcomes. Improvement of the lesions was assessed by magnetic resonance imaging (MRI) at year 1 postoperatively at the earliest.

RESULTS

The mean lesion size was 1.32 cm² (range 0.8-1.8 cm²). The mean pre- and postoperative VPS values were calculated to be 75.5 ± 12.32 (range 46-92) and 17.57 ± 10.21 (range 0-40), respectively ( p < 0.01). The mean pre- and postoperative Lysholm knee scores were 44.57 ± 9.35 (range 26-65) and 80 ± 6.9 (range 70-94), respectively ( p < 0.01), and the mean pre- and postoperative Kujala anterior knee pain scores were 48.21 ± 7.78 (range 38-68) and 78.42 ± 7.06 (range 70-96), respectively ( p < 0.01). MRI taken at year 1 postoperatively showed that the autograft bone tissue was sufficiently incorporated into the recipient site in all patients; an even articular surface was formed, but the thickness of the cartilage tissue was mostly uneven between the adjacency of the recipient site and the autograft, which caused no negative effect on clinical and functional outcomes.

CONCLUSIONS

Despite the difference in thickness of the cartilage tissue between the recipient and the donor site, the AOT technique for the treatment of patellar osteochondral lesions resolves the symptoms of the patient and ensures an apparent functional and clinical improvement even if an articular surface could be created.

Small Subchondral Drill Holes Improve Marrow Stimulation of Rotator Cuff Repair in a Rabbit Model of Chronic Rotator Cuff Tear

BACKGROUND

Microfracture of the greater tuberosity has been proved effective for enhancing tendon-to-bone healing after rotator cuff repair. However, no standard diameter for the microfracture has been established.

PURPOSE/HYPOTHESIS

This study aimed to assess treatment with large- and small-diameter microfractures to enhance healing during rotator cuff repair surgery in a rabbit model of chronic rotator cuff tear. It was hypothesized that a small-diameter microfracture had advantages in terms of tendon-to-bone integration, bone-tendon interface maturity, microfracture healing, and biomechanical properties compared with a large-diameter microfracture.

STUDY DESIGN

Controlled laboratory study.

METHODS

Bilateral supraspinatus tenotomy from the greater tuberosity was performed on 21 New Zealand White rabbits. Bilateral supraspinatus repair was performed 6 weeks later. Small-diameter (0.5 mm) microfracture and large-diameter microfracture (1 mm) were performed on the left side and right side, respectively, in 14 rabbits as a study group, and simple repair without microfracture was performed in 7 rabbits as a control group. At 12 weeks later, 7 of 14 rabbits in the study group were sacrificed for micro-computed tomography evaluation and biomechanical testing. Another 6 rabbits were sacrificed for histological evaluation. In the control group, 3 of the 7 rabbits were sacrificed for histological evaluation and the remaining rabbits were sacrificed for biomechanical testing.

RESULTS

Significantly better bone-to-tendon integration was observed in the small-diameter microfracture group. Better histological formation and maturity of the bone-tendon interface corresponding to better biomechanical results (maximum load to failure and stiffness) were obtained on the small-diameter microfracture side compared with the large-diameter side and the control group. The large-diameter microfracture showed worse radiographic and histological properties for healing of the microfracture holes on the greater tuberosity. Additionally, the large-diameter microfracture showed inferior biomechanical properties but similar histological results compared with the control group.

CONCLUSION

Small-diameter microfracture showed advantages with enhanced rotator cuff healing for biomechanical, histological, and radiographic outcomes compared with large-diameter microfracture, and large-diameter microfracture may worsen the rotator cuff healing.

CLINICAL RELEVANCE

This animal study suggested that a smaller diameter microfracture may be a better choice to enhance healing in clinical rotator cuff repair surgery in humans.

Biologically Regulated Marrow Stimulation by Blocking TGF-β1 With Losartan Oral Administration Results in Hyaline-like Cartilage Repair: A Rabbit Osteochondral Defect Model

BACKGROUND

Microfracture or bone marrow stimulation (BMS) is often the first choice for clinical treatment of cartilage injuries; however, fibrocartilage, not pure hyaline cartilage, has been reported because of the development of fibrosis in the repair tissue. Transforming growth factor β1 (TGF-β1), which can promote fibrosis, can be inhibited by losartan and potentially be used to reduce fibrocartilage.

HYPOTHESIS

Blocking TGF-β1 would improve cartilage healing in a rabbit knee BMS model via decreasing the amount of fibrocartilage and increasing hyaline-like cartilage formation.

STUDY DESIGN

Controlled laboratory study.

METHODS

An osteochondral defect was made in the patellar groove of 48 New Zealand White rabbits. The rabbits were divided into 3 groups: a defect group (defect only), a BMS group (osteochondral defect + BMS), and a BMS + losartan group (osteochondral defect + BMS + losartan). For the rabbits in the BMS + losartan group, losartan was administrated orally from the day after surgery through the day of euthanasia. Rabbits were sacrificed 6 or 12 weeks postoperatively. Macroscopic appearance, microcomputed tomography, histological assessment, and TGF-β1 signaling pathway were evaluated at 6 and 12 weeks postoperatively.

RESULTS

The macroscopic assessment of the repair revealed that the BMS + losartan group was superior to the other groups tested. Microcomputed tomography showed superior healing of the bony defect in the BMS + losartan group in comparison with the other groups. Histologically, fibrosis in the repair tissue of the BMS + losartan group was significantly reduced when compared with the other groups. Results obtained with the modified O'Driscoll International Cartilage Repair Society grading system yielded significantly superior scores in the BMS + losartan group as compared with both the defect group and the BMS group (F value: 15.8, P < .001, P = .012, respectively). TGF-β1 signaling and TGF-β-activated kinase 1 of the BMS + losartan group were significantly suppressed in the synovial tissues.

CONCLUSION

By blocking TGF-β1 with losartan, the repair cartilage tissue after BMS was superior to the other groups and consisted primarily of hyaline cartilage. These results should be easily translated to the clinic because losartan is a Food and Drug Administration-approved drug and it can be combined with the BMS technique for optimal repair of chondral defects.

CLINICAL RELEVANCE

Biologically regulated marrow stimulation by blocking TGF-β1 (oral intake of losartan) provides superior repair via decreasing fibrocartilage formation and resulting in hyaline-like cartilage as compared with outcomes from BMS only.

Autologous Chondrocyte Implantation and Osteochondral Allograft Transplantation Render Comparable Outcomes in the Setting of Failed Marrow Stimulation

BACKGROUND

Marrow stimulation techniques (MSTs) such as subchondral drilling and microfracture are often chosen as first-line treatment options for symptomatic cartilage defects of the knee. When an MST fails, many cartilage restoration techniques are employed, including autologous chondrocyte implantation (ACI) and osteochondral allograft (OCA). However, a few series in the literature suggest that ACI after a failed MST results in inferior outcomes as compared with primary ACI.

PURPOSE/HYPOTHESIS

The purpose of this study was (1) to evaluate the clinical outcomes of ACI and OCA after a failed MST (secondary ACI and OCA) and compare them with the outcomes of primary ACI and OCA and (2) to compare clinical outcomes of secondary ACI and secondary OCA for refractory lesions involving the femoral condyle. The hypotheses were as follows: (1) secondary ACI will render inferior functional outcomes and an increased clinical failure rate as compared with primary ACI, (2) secondary OCA will render comparable results to primary OCA, and (3) secondary OCA will render superior outcomes to secondary ACI.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Patients were retrospectively identified who underwent ACI and OCA for symptomatic chondral lesions of the knee refractory to a previous MST. Age-, sex-, and body mass index-matched groups of patients undergoing primary ACI and OCA were used as controls. Postoperative data were prospectively collected using several subjective scoring systems (Tegner, Lysholm, International Knee Documentation Committee, Knee injury and Osteoarthritis Outcome Score, 12-Item Short Form Health Survey). Groups were compared with regard to patient-reported outcomes, subjective satisfaction, clinical failure rate, and reoperation. Student t tests were used for continuous data, and chi-square tests were performed for categorical data.

RESULTS

A total of 359 patients were examined: 92 patients undergoing secondary ACI, 100 primary ACI, 88 secondary OCA, and 79 primary OCA. The mean patient age was 30.3 years (range, 14.9-49.9 years) at the time of ACI and 35.4 (range, 15-54.5) at the time of OCA. There was no difference between the primary and secondary groups with regard to postoperative functional scores, subjective satisfaction, reoperation rate, and clinical failure rate.

CONCLUSION

ACI and OCA are both viable treatment options for chondral defects of the knee, even in the setting of a failed MST. Secondary ACI renders functional outcomes, subjective satisfaction, and reoperation and failure rates comparable with primary ACI and secondary OCA.

Human adipose-derived mesenchymal progenitor cells plus microfracture and hyaluronic acid for cartilage repair: a Phase IIa trial

Aim: This study aimed to preliminarily evaluate the safety and efficacy of human adipose-derived mesenchymal progenitor cells (haMPCs) in combination with microfracture and hyaluronic acid (HA) for treating cartilage defects. Materials & methods: A total of 30 patients with medial femoro-tibial condylar cartilage defects were randomized into three groups: arthroscopic microfracture group and normal saline injection, arthroscopic microfracture and intra-articular injection of HA, or arthroscopic microfracture in combination with intra-articular injection of HA and haMPCs. Results & conclusions: The data demonstrated that intra-articular injection of haMPCs plus microfracture and HA is a safe procedure to improve joint function in patients with knee cartilage defects. These findings provide an impetus for future research on this treatment. ClinicalTrials.gov Identifier: NCT02855073.

Mesenchymal stem cells for cartilage regeneration

Cartilage injuries are typically caused by trauma, chronic overload, and autoimmune diseases. Owing to the avascular structure and low metabolic activities of chondrocytes, cartilage generally does not self-repair following an injury. Currently, clinical interventions for cartilage injuries include chondrocyte implantation, microfracture, and osteochondral transplantation. However, rather than restoring cartilage integrity, these methods only postpone further cartilage deterioration. Stem cell therapies, especially mesenchymal stem cell (MSCs) therapies, were found to be a feasible strategy in the treatment of cartilage injuries. MSCs can easily be isolated from mesenchymal tissue and be differentiated into chondrocytes with the support of chondrogenic factors or scaffolds to repair damaged cartilage tissue. In this review, we highlighted the full success of cartilage repair using MSCs, or MSCs in combination with chondrogenic factors and scaffolds, and predicted their pros and cons for prospective translation to clinical practice.

Articular Cartilage Repair of the Pediatric and Adolescent Knee with Regard to Minimal Clinically Important Difference: A Systematic Review

OBJECTIVE

To perform a systematic review of clinical outcomes following microfracture (MFX), autologous chondrocyte implantation (ACI), osteochondral allograft transplantation (OCA), and osteochondral autograft transplantation system (OATS) to treat articular cartilage lesions in pediatric and adolescent patients. We sought to compare postoperative improvements for each cartilage repair method to minimal clinically important difference (MCID) thresholds.

DESIGN

MEDLINE, Web of Science, Scopus, and Cochrane Library databases were searched for studies reporting MCID-validated outcome scores in a minimum of 5 patients ≤19 years treated for symptomatic knee chondral lesions with minimum 1-year follow-up. One-sample t tests were used to compare mean outcome score improvements to established MCID thresholds.

RESULTS

Twelve studies reporting clinical outcomes on a total of 330 patients following cartilage repair were identified. The mean age of patients ranged from 13.7 to 16.7 years and the mean follow-up was 2.2 to 9.6 years. Six studies reported on ACI, 4 studies reported on MFX, 2 studies reported on OATS, and 1 study reported on OCA. ACI (P < 0.001, P = 0.008) and OCA (P < 0.001) showed significant improvement for International Knee Documentation Committee (IKDC) scores with regard to MCID while MFX (P = 0.66) and OATS (P = 0.11) did not. ACI (P < 0.001) and OATS (P = 0.010) both showed significant improvement above MCID thresholds for Lysholm scores. MFX (P = 0.002) showed visual analog scale (VAS) pain score improvement above MCID threshold while ACI (P = 0.037, P = 0.070) was equivocal.

CONCLUSIONS

Outcomes data on cartilage repair in the pediatric and adolescent knee are limited. This review demonstrates that all available procedures provide postoperative improvement above published MCID thresholds for at least one reported clinical pain or functional outcome score.

Systematic Review of Patient Outcomes and Associated Predictors After Microfracture in the Patellofemoral Joint

We summarized the clinical outcomes and predictors of clinical outcomes after microfracture for chondral lesions in the patellofemoral joint (PFJ).

Knee surgery: Trends and the 50 most cited articles

Knee Surgery is one of the most commonly performed orthopedic procedures, and a rapidly evolving area of research. A bibliographic analysis was conducted to explore the characteristics of the top 50 most cited articles in knee surgery. The Web of Science Core Collection Database was used to search for Knee AND Surgery, further refined for orthopedic surgery, yielding 1,660 articles. After inclusion and exclusion criteria were applied, the top 50 cited articles were statistically and thematically analyzed. Year of publication ranged from 1982 to 2014. The highest volume of research came from USA, with the Journal of Bone and Joint Surgery having the highest number of papers in the top 50. The most common theme of research was Knee Arthroplasty Outcomes. Our study elucidates trends and popular areas of research in the field of knee surgery, and provides researchers with an overview of areas to focus, where there is scope for high-impact original research.

Equivalent 10-Year Outcomes After Implantation of Autologous Bone Marrow-Derived Mesenchymal Stem Cells Versus Autologous Chondrocyte Implantation for Chondral Defects of the Knee

BACKGROUND

The use of bone marrow-derived mesenchymal stem cells (BMSCs) in cartilage repair procedures circumvents some of the limitations of autologous chondrocyte implantation (ACI), but long-term outcomes for this newer procedure are lacking. The authors previously reported comparable outcomes for the 2 procedures at 2-year follow-up.

PURPOSE/HYPOTHESIS

The purpose was to compare the long-term clinical outcomes of ACI versus BMSCs. It was hypothesized that there would be no significant difference between the groups in terms of patient-reported outcome scores and safety outcomes at 10-year follow-up.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Seventy-two patients who underwent either ACI or BMSC implantation-matched in terms of age and lesion site- were followed up to a median of at least 10 years. Patients were assessed with the 36-item Short Form Health Survey (SF-36), the International Knee Documentation Committee knee evaluation form, the Lysholm Knee Score, and the Tegner Activity Scale. In addition, information was obtained regarding any additional surgical procedures as well as safety data, with particular attention to infection and tumor formation.

RESULTS

There was an improvement in all patient-reported outcomes scores apart from the Mental Component Summary of the SF-36 after cartilage repair surgery. There was no significant difference in any of the patient-reported outcomes between cohorts at any time point. Six and 5 patients in the ACI and BMSC groups, respectively, underwent subsequent surgical procedures, including 1 total knee replacement in the BMSC group. None of the patients in either group developed any deep infection or tumor within the follow-up period.

CONCLUSION

BMSC implantation used for the treatment of chondral defects of the knee appears to result in equivalent clinical outcomes to first-generation ACI at up to 10 years, with no apparent increased tumor formation risk.

Adjuvant therapies for the enhancement of microfracture technique in cartilage repair

The classic technique of microfracture does not promote hyaline cartilage restoration. Subchondral bone perforations lead to the formation of a clot containing pluripotent progenitor cells and finally the cartilage defect is filled by fibrocartilage tissue. Researchers have focused on enhancing the quality of the newly formed tissue in cartilage defects after microfracture arthroscopic surgery. Adjuvant treatments are categorized in four main groups: scaffolds, pharmaceutical agents, growth factors and combinations of the aforementioned. Several experimental studies utilize pharmaceutical or biological agents in combination with microfracture, to improve the quality of the regenerated cartilage. The mechanism of action of the agents used is either to exert a chondroprotective effect on the newly formed fibrocartilage tissue, or to induce the recruitment of mesenchymal stem cells towards chondrogenesis instead of osteogenesis during microfracture repair. Additionally, scaffolds have been used for both release of the biological agents and mechanical support of the newly formed blood clot. This review highlights current data regarding the combination of microfracture technique with adjuvant treatments in order to ameliorate the final outcome.

Chondro-protective effects of polydatin in osteoarthritis through its effect on restoring dysregulated autophagy via modulating MAPK, and PI3K/Akt signaling pathways

Osteoarthritis (OA) is a degenerative disease of the cartilage that is prevalent in the middle-aged and elderly demography. Polydatin (PD), a natural resveratrol glucoside, has shown significant anti-inflammatory and anti-arthritic potential in previous studies. This study was designed to evaluate the therapeutic properties of PD in vitro and in vivo, and elucidate their underlying mechanisms. The expression levels of all relevant factors were evaluated by qRT-PCR, western blotting, and immunohistochemistry (IHC) where suitable. Reactive oxygen species (ROS) and apoptosis were analyzed using the suitable probes and flow cytometry. The histological evidence of cartilage was assessed in rat models, moreover, the several serum cytokines levels and autophagy levels were evaluated. The result showed PD displayed significant chondro-protective effects, inferred in terms of reduced inflammation and cartilage degradation, apoptosis inhibition, and lower ROS production. The protective effects were attenuated by the autophagy inhibitor 3-MA, indicating a mediating role of autophagy in PD action. Mechanistically, PD exerted its effects by inhibiting the MAPK and PI3K/Akt signaling pathways which led to the down-regulation of mTOR. In conclusion, PD protects against cartilage degeneration by activating the autophagy flux in the chondrocytes via the MAPK and PI3K/Akt signaling pathways.

[What does the clinician expect from the radiologist regarding cartilage-specific imaging?]

CLINICAL ISSUE

Today's advanced MRI imaging allows for a precise diagnosis and thus better treatment planning of cartilage damage. The phrase "depending on intraoperative findings" is therefore slowly becoming a thing of the past. However, this also increases the demand for an exact interpretation of the imaging, from clinicians and patients alike. This article highlights the importance of a radiologist's role in different constellations.

PRACTICAL RECOMMENDATIONS

In the case of acute injuries, it is crucial to recognize osteochondral flakes, cartilage delamination, subchondral bone bruising and fractures as well as concomitant injuries. These findings must be instantly communicated to the practitioner. In the case of chronic cartilage damage, grading the extent and size of the damage is decisive in choosing the appropriate therapy method. Possible causes and accompanying injuries must also be analyzed and, if necessary, addressed. Direct communication with the clinical colleague is also useful in correlating the clinical and radiological findings.

Effectiveness of Adhering Adipose-Derived Stem Cells to Defective Cartilage in Promoting Cartilage Regeneration in a Rabbit Model

PURPOSE

To evaluate the therapeutic effect of using a local adherent technique to transplant adipose-derived stem cells (ADSCs) for cartilage regeneration in a rabbit model for patients with traumatic damage or osteochondritis dissecans.

METHODS

Cartilage defects were created in the trochlear groove of 60 adult white rabbit knees. The rabbits were either left untreated (control group), treated with intra-articularly injected ADSCs (injected group), or treated by adhering ADSCs (adherent group). The 3 groups were compared at 4, 12, and 24 weeks postoperatively using the International Cartilage Repair Society macroscopic scoring system and a modified Wakitani histologic grading system to quantitatively evaluate the regenerated cartilage. The degree of defect repair, integration to the border zone, macroscopic appearance, cell morphology, matrix staining, surface regularity, cartilage thickness, and integration of the donor with the host were evaluated.

RESULTS

The mean International Cartilage Repair Society scores in the control, injected, and adherent groups were 6.4 ± 2.9, 7.6 ± 0.8, and 7.6 ± 1.4, respectively, at 4 weeks; 6.2 ± 2.4, 8.2 ± 1.5, and 9.6 ± 1.0, respectively, at 8 weeks; and 7.6 ± 1.0, 8.4 ± 1.4, and 10.2 ± 1.7, respectively, at 24 weeks. Although the scores were higher in the adherent group, no significant difference was noted. The mean modified Wakitani scores in the control, injected, and adherent groups were 3.8 ± 2.0, 5.1 ± 1.8, and 7.8 ± 1.3, respectively, at 4 weeks (P = .041); 5.1 ± 1.0, 5.4 ± 2.7, and 9.6 ± 1.4, respectively, at 12 weeks (P = .016); and 5.4 ± 1.0, 5.9 ± 1.5, and 9.8 ± 1.8, respectively, at 24 weeks (P = .007).

CONCLUSIONS

The histologic modified Wakitani scores showed that adhering ADSCs to osteochondral cartilage defects was more effective than intra-articular injection for promoting cartilage regeneration.

CLINICAL RELEVANCE

Local adhesion of ADSCs can promote cartilage regeneration and may be a treatment option for cartilage repair.

Enzyme Pretreatment plus Locally Delivered HB-IGF-1 Stimulate Integrative Cartilage Repair In Vitro

IMPACT STATEMENT

A critical attribute for the long-term success of cartilage defect repair is the strong integration between the repair tissue and the surrounding native tissue. Current approaches utilized by physicians fail to achieve this attribute, leading to eventual relapse of the defect. This article demonstrates the concept of a simple, clinically viable approach for enhancing tissue integration via the combination of a safe, transient enzymatic treatment with a locally delivered, retained growth factor through an in vitro hydrogel/cartilage explant model.

Enhancement of cartilage repair through the addition of growth plate chondrocytes in an immature skeleton animal model

Background

The treatment of articular cartilage damage is a major clinical problem. More often, this clinical issue affects children, which forces doctors to find the best treatment method.

Methods

The aim of this experimental study on 2-month-old Landrace pigs was to compare the results of two cartilage defect treatments: (1) filling the cartilage defect with a scaffold incubated with bone marrow aspirate supplemented with growth plate chondrocytes (the CELLS group) and (2) filling the cartilage defect with an empty scaffold implanted after drilling the subchondral bone (the CTRL group). The treatment outcomes were assessed macroscopically and microscopically.

Results

Based on the macroscopic evaluation, all animals showed a nearly normal morphology, with an average of 9.66/12 points (CTRL) and 10.44/12 points (CELLS). Based on the microscopic evaluation, 1 very good result and 8 good results were obtained in the CTRL group, with an average of 70.44%, while 5 very good results and 4 good results were obtained in the CELLS group, with an average of 79.61%.

Conclusions

(1) Growth plate chondrocytes have high chondrogenic potential and thus offer new possibilities for cartilage cell therapy. (2) The implantation of a scaffold loaded with bone marrow-derived MSCs (mesenchymal stem cells) and growth plate chondrocytes into a cartilage defect is a good therapeutic method in immature patients. (3) Cartilage repair based on a scaffold with bone marrow aspirate-derived cells supplemented with autologous growth plate chondrocytes achieves better results than repair with marrow stimulation and a hyaluronic acid-based scaffold (overall microscopic rating). (4) Chondrocyte clustering is a manifestation of the cartilage repair process but requires further observation.

Electronic supplementary material

The online version of this article (10.1186/s13018-019-1302-y) contains supplementary material, which is available to authorized users.

Clinical and Radiological Changes after Microfracture of Knee Chondral Lesions in Middle-Aged Asian Patients

Background

Although microfracture is widely accepted as an effective treatment option for knee chondral lesions, little is known about the deterioration of clinical outcomes and radiological progression in middle-aged patients. Therefore, this study was conducted to evaluate the clinical and radiological changes after microfracture of knee chondral lesions in middle-aged Asian patients.

Methods

A total of 71 patients were included in the study. They were between the ages of 40 and 60 years and underwent arthroscopic microfracture for localized full-thickness cartilage defects of the knee from January 2000 to September 2015. The recovery status of chondral lesions was assessed by using the magnetic resonance observation of cartilage repair tissue (MOCART) score in postoperative magnetic resonance imaging (MRI). Clinical and radiological results were reviewed, and survival rate with conversion to arthroplasty or osteotomy as an end point was evaluated.

Results

The mean age of the patients at surgery was 51.3 ± 4.7 years (range, 40 to 60 years), and the mean follow-up period was 7.2 ± 2.6 years (range, 1.0 to 17.4 years). The MOCART scores of 32 patients at mean postoperative 2.1 years showed three cases (9%) of full recovery, two cases (7%) of hyperplastic recovery, 23 cases (70%) with more than 50% filling, and four cases (14%) with less than 50% filling. Clinical scores improved significantly at 1 year after surgery (p < 0.05); however, the scores deteriorated over time after postoperative 1 year, and the mean values reached preoperative levels at postoperative 10 years. Significant radiological progression of arthritis (Kellgren-Lawrence grade) was observed at 5 years after surgery. Four patients underwent total knee arthroplasty during follow-up.

Conclusions

Most patients showed more than 50% of defect filling at 2 years after surgery on MRI. Clinical results of microfracture of knee chondral lesion showed the best improvement at postoperative 1 year but gradually worsened thereafter until postoperative 10 years. Radiological progression of arthritis was observed from 5 years after surgery.

Current surgical options and innovation for repairing articular cartilage defects in the femoral head

Total hip arthroplasty is a common surgical technique, yet it has severe complications, such as loosening and repeated revision. Thus, hip-preserving surgical options should be considered first to treat cartilage defects in the femoral head, especially for younger patients. Current surgical options for chondral repair of the femoral head include microfracture, trapdoor procedure, transplantation of osteochondral allografts and autografts, and autologous chondrocyte implantation. Each of these techniques has unique advantages and limitations; however, none of them have been consented as the best practice for cartilage defects. In this review article, we also introduced a novel technique for repairing osteochondral defects of the femoral head using autologous costal cartilage grafts that may have good translational potential for cost-effective and safe applications.

The translational potential of this article

This review updates current surgical options for reparing articular cartilage defects in the femoral head. We also introduce a novel technique for repairing osteochondral defects of the femoral head using autologous costal cartilage grafts.

Enrichment of CD146+ Adipose-Derived Stem Cells in Combination with Articular Cartilage Extracellular Matrix Scaffold Promotes Cartilage Regeneration

Heterogeneity of mesenchymal stem cells (MSCs) influences the cell therapy outcome and the application in tissue engineering. Also, the application of subpopulations of MSCs in cartilage regeneration remains poorly characterized. CD146+ MSCs are identified as the natural ancestors of MSCs and the expression of CD146 are indicative of greater pluripotency and self-renewal potential. Here, we sorted a CD146+ subpopulation from adipose-derived mesenchymal stem cells (ADSCs) for cartilage regeneration. Methods: CD146+ ADSCs were sorted using magnetic activated cell sorting (MACS). Cell surface markers, viability, apoptosis and proliferation were evaluated in vitro. The molecular signatures were analyzed by mRNA and protein expression profiling. By intra-articular injections of cells in a rat osteochondral defect model, we assessed the role of the specific subpopulation in cartilage microenvironment. Finally, CD146+ ADSCs were combined with articular cartilage extracellular matrix (ACECM) scaffold for long term (3, 6 months) cartilage repair. Results: The enriched CD146+ ADSCs showed a high expression of stem cell and pericyte markers, good viability, and immune characteristics to avoid allogeneic rejection. Gene and protein expression profiles revealed that the CD146+ ADSCs had different cellular functions especially in regulation inflammation. In a rat model, CD146+ ADSCs showed a better inflammation-modulating property in the early stage of intra-articular injections. Importantly, CD146+ ADSCs exhibited good biocompatibility with the ACECM scaffold and the CD146+ cell-scaffold composites produced less subcutaneous inflammation. The combination of CD146+ ADSCs with ACECM scaffold can promote better cartilage regeneration in the long term. Conclusion: Our data elucidated the function of the CD146+ ADSC subpopulation, established their role in promoting cartilage repair, and highlighted the significance of cell subpopulations as a novel therapeutic for cartilage regeneration.

Severe Bone Marrow Edema Among Patients Who Underwent Prior Marrow Stimulation Technique Is a Significant Predictor of Graft Failure After Autologous Chondrocyte Implantation

BACKGROUND

Autologous chondrocyte implantation (ACI) is a well-established cartilage repair procedure; however, numerous studies have shown higher ACI graft failure rates after prior marrow stimulation techniques (MSTs).

PURPOSE

To identify which factors may predict decreased graft survival after ACI among patients who underwent a prior MST. A secondary aim was to investigate the specificity of these predictors.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

In this review of prospectively collected data, the authors analyzed 38 patients who had failed prior MST surgery and subsequently underwent collagen-covered ACI (case group). The case group was divided into graft failure ACI (n = 8, 21%) and successful ACI (n = 30, 79%). Fourteen clinical variables were categorized and analyzed to determine predictors for failure of the ACI graft: age, body mass index, sex, defect characteristics (number, size, location, etiology, type), presence of kissing lesion, intraoperative presence of intralesional osteophyte, time between an MST and ACI, previous surgery, duration of the symptoms, and concomitant surgical procedure. Preoperative magnetic resonance imaging (MRI) was used to evaluate the severity of subchondral bone marrow edema (BME), graded I (absent) to IV (severe), and the presence of subchondral cyst, hypertrophic sclerosis, and intralesional osteophyte. The effects of these MRI findings on the graft survivor were also investigated. Concurrently, a control group without a prior MST was matched to investigate the specificity of the previously determined predictors. These patients were matched individually according to age, sex, body mass index, and outcome of the procedure (failure [n = 8] or successful [n = 30] per the case group).

RESULTS

In the case group, the presence of preoperative severe BME was significantly higher among patients with failed ACI as compared with patients with successful ACI (P < .001). In the control group, the presence of severe BME was not significantly different between the failure and successful groups (P = .747). The ACI graft failure rate among patients with a prior MST and preoperative grade IV BME was 83.7% at 5 years postoperatively, resulting in a significantly lower survival rate as compared with patients with a prior MST and without severe BME (5-year graft failure rate, 6.5%; P < .001). All the other parameters did not differ significantly.

CONCLUSION

After a prior MST, the presence of grade IV BME by MRI was a predictive factor for graft failure among patients who then underwent second-generation ACI.

Autologous Osteochondral Transplantation in Full-thickness Patella Chondral Lesion: A Case Series

Purpose

Autologous osteochondral transplantation (AOT) in the focal cartilage lesion of the patella has been reported with less successful results compared with other sites. The purposes were to investigate the clinical outcomes of AOT for focal patellar chondral lesion without patellofemoral instability.

Methods

Between 2001 and 2007, six patients (five males and one female) with a focal patellar cartilage lesion without patellofemoral malalignment and instability were treated with AOT. The mean age was 38 (27-51) years. Intraoperatively, the size and location of lesion were assessed by international cartilage repair society classification. Lysholm score was investigated preoperatively, at 6 months, 1- and 2-year, and final follow-up. Mean follow-up period was 51 months (24-101). Transplanted grafts were evaluated by magnetic resonance imaging (MRI) and second-look arthroscopy.

Results

The mean size was 133mm2(78-225). All six cases improved at final follow-up (Lysholm score 79-100). Although immediate pain relief obtained in four cases, severe pain was persistent in remaining two cases during the 1styear and gradually relieved by 2 years following surgery. The size of these two cases was significantly larger (over 170 mm2) than that of four cases (100 mm2 in average) (P<0.05), and their locations were apart from center of the patella inspite of four cases localized centrally (P<0.05). Repaired cartilage did not show any difference by MRI and arthroscopically.

Conclusion

AOT in focal patellar chondral lesions without patellofemoral malalignment showed excellent results. In cases of large off-centeredlesions, however, it took longer for pain relief following AOT.

Is implantation of autologous chondrocytes superior to microfracture for articular-cartilage defects of the knee? A systematic review of 5-year follow-up data

BACKGROUND

Autologous chondrocyte implantation (ACI) and microfracture are two of the main surgical treatment options for articular cartilage lesions of the knee. Consensus regarding the best clinical options to repair knee cartilage lesions is lacking. We undertook a systematic review to clarify the clinical efficacy of ACI and microfracture at minimum mean 5-year follow-up.

METHODS

A literature search was conducted using the MEDLINE, Embase and Cochrane Library databases up to August 2018. Only comparative clinical studies of ACI and microfracture for the treatment of articular cartilage lesions of the knee with level I/Ⅱ evidence were included. Clinical outcomes and the prevalence of treatment failure from each study were extracted and compared. The methodological quality of the included studies was analyzed by means of the PEDro scale.

RESULTS

Five comparative studies (three randomized controlled trials and two prospective cohort studies) met our eligibility criteria. ACI and microfracture elicited significant improvement in clinical outcomes after 5 years. However, better clinical results with significant differences were found with modified versions of ACI (ACI with a modified collagen membrane [ACI-C] or matrix-applied chondrocyte implantation [MACI]) than with microfracture as determined by the Knee Injury and Osteoarthritis Outcome Score, activities of daily living assessment, Tegner Activity Scale score, and the International Knee Documentation Committee objective and subjective scores. No significant difference was observed in the treatment failure rate between these two methods within a particular study.

CONCLUSIONS

Currently, the best-available evidence suggests that some clinical outcomes of articular cartilage lesions of the knee treated with modified versions of ACI (ACI-C or MACI) can significantly improve patient outcomes at the mid-term follow-up of 5 years compared with those obtained using microfracture.