Prospective clinical and radiologic evaluation of patellofemoral matrix-induced autologous chondrocyte implantation

Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) Scores > 55 at 6 Months Postoperative Predict Ability to Achieve Patient Acceptable Symptomatic State at Minimum 1 Year Postoperative Following Autologous Chondrocyte Implantation for Grade IV Chondral Defects About the Patellofemoral Joint

PURPOSE

The primary aim is to evaluate the relationship between MOCART scores and patient satisfaction, as evaluated by achievement of (1) the Patient Acceptable Symptomatic State (PASS) and (2) the minimal clinically important difference (MCID) for Knee Injury and Osteoarthritis Score Quality of Life (KOOS QoL), for patients undergoing autologous chondrocyte implantation (ACI) for focal Grade IV patellofemoral chondral defects. The secondary aim is to determine the threshold MOCART score which predicts the ability to meet the PASS and the MCID for KOOS QoL.

METHODS

Patients undergoing ACI for grade IV patellofemoral chondral defects by a single surgeon from 2017 to 2020 were identified by search of the EMR. To determine PASS status, patients were asked, "Do you consider your current level of symptoms to be acceptable?" KOOS QoL scores were also collected. Patients with 6-month postoperative knee MRI, PASS scores, and minimum 2-year follow-up data were included. Paired t tests and Wilcoxon Rank-Sum tests were used to evaluate the relationship between MOCART scores and (1) PASS achievement and (2) achievement of the MCID for KOOS QoL (12.8).

RESULTS

Thirty-four patients were included, with a median age of 35.1 years [IQR: 24.6, 37.1], and BMI of 24.0 kg/m2 [IQR: 21.5, 28.1]. The median time to postoperative MRI was 6.7 months [IQR: 5.8, 7.9], and average follow-up time was 3.7 ± 1.2 years. Twenty-five patients (74%) achieved PASS, and 18 patients (out of 27 who had postop KOOS QoL Scores, 67%) achieved the MCID for KOOS QoL. Patients who achieved PASS had higher average MOCART scores (61.8 ± 16.0) than those who did not achieve PASS (45.0 ± 12.8, p=0.011), whereas patients who achieved the MCID for KOOS QoL did not have higher MOCART scores than those who did not achieve the MCID (61.9 ± 18.3 versus 53.3 ± 17.1, P = 0.25). There was no relationship between age, sex, lesion size, and lesion location and ability to achieve PASS or MCID for KOOS QoL (p>0.05). A threshold MOCART value of 55 was associated with the highest AUC on ROC analysis for likelihood of achieving PASS (0.778) and MCID for KOOS QoL (0.667).

CONCLUSION

Higher MOCART scores are associated with an increased likelihood of achieving PASS following patellofemoral ACI. Moreover, MOCART scores > 55 predict the ability to achieve PASS and the MCID for KOOS QoL following patellofemoral ACI.

LEVEL OF EVIDENCE

IV.

Treatment of cartilage defects in the patellofemoral joint with matrix-associated autologous chondrocyte implantation effectively improves pain, function, and radiological outcomes after 5-7 years

INTRODUCTION

The aim of the present study was to evaluate midterm outcomes 5-7 years after matrix-associated autologous chondrocyte implantation (MACI) in the patellofemoral joint.

MATERIALS AND METHODS

Twenty-six patients who had undergone MACI using the Novocart® 3D scaffold were prospectively evaluated. Clinical outcomes were determined by measuring the 36-Item Short-Form Health Survey (SF-36) and International Knee Documentation Committee (IKDC) scores and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) values preoperatively and 3, 6, and 12 months, and a mean of 6 years postoperatively. At the final follow-up, the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score was evaluated.

RESULTS

Twenty-two patients with 23 focal cartilage defects (19 patella and four trochlea) were available for the final follow-up. The mean defect size was 4.0 ± 1.9 cm2 (range 2.4-9.4 cm2). All clinical outcome scores improved significantly until 5-7 years after MACI (SF-36 score, 61.2 ± 19.6 to 83.2 ± 11.6; P = 0.001; IKDC score, 47.5 ± 20.6 to 74.7 ± 15.5; P < 0.001; and WOMAC, 29.8 ± 15.7 to 8.2 ± 10.3; P < 0.001). The mean MOCART score was 76.0 ± 11.0 at the final follow-up. Nineteen of the 22 patients (86.4%) were satisfied with the outcomes after 5-7 years and responded that they would undergo the procedure again.

CONCLUSION

MACI in the patellofemoral joint demonstrated good midterm clinical results with a significant reduction in pain, improvement in function, and high patient satisfaction. These clinical findings are supported by radiological evidence from MOCART scores.

LEVEL OF EVIDENCE

IV-case series.

Impact of Wiberg Patellar Type on Outcomes and Survival Following Cell-Based Cartilage Repair for Patellar Chondral Lesions at Midterm Follow-up

BACKGROUND

Cell-based cartilage repair procedures of the patellofemoral joint have less reliable outcomes than those of the tibiofemoral joint. No previous studies have evaluated the influence of patellar shape on cell-based cartilage repair outcomes. Patellar dysplasia may predispose patients to worse outcomes after cell-based cartilage repair.

PURPOSE/HYPOTHESIS

The purpose of this study was to evaluate the relationship between Wiberg patellar type and outcomes after cell-based cartilage repair (autologous chondrocyte implantation or particulated juvenile allograft cartilage transplantation) for the treatment of patellar chondral lesions at a minimum 2-year follow-up. It was hypothesized that Wiberg classification of patellar shape would have no effect on patient-reported outcome measures (PROMs) or graft survival.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Patients undergoing autologous chondrocyte implantation or particulated juvenile allograft cartilage transplantation for full-thickness patellar chondral defects between 2016 and 2020 were retrospectively reviewed after institutional review board approval. The change in PROMs, including International Knee Documentation Committee (IKDC), Kujala, and Veterans RAND 12-item Health Survey Mental and Physical scores, from pre- to postoperatively and the percentage of patients who achieved the minimal clinically important difference (MCID) for IKDC and Kujala scores were compared for the Wiberg type A versus Wiberg type B versus Wiberg type C groups. The log-rank test was used to evaluate for differences in survival between subgroups.

RESULTS

A total of 59 patients (63 knees) were included, with a mean age of 33.3 ± 8.6 years, median body mass index of 26.0 (IQR, 21.8-30.2), and median follow-up time of 3.5 years (IQR, 2.6-4.2 years). In total, 26 (41%) patellae were Wiberg type A, 29 (46%) were Wiberg type B, and 8 (13%) were Wiberg type C. There were no differences between Wiberg type A versus Wiberg type B versus Wiberg type C groups with respect to change in PROMs from pre- to postoperatively or the percentage of patients who achieved the MCID for IKDC or Kujala scores (P > .05 for all). There were no differences in survival between groups (P = .45).

CONCLUSION

Wiberg patellar type has no effect on patient-reported outcomes or graft survival at midterm follow-up. Patellar dysplasia should not be seen as a contraindication for cell-based cartilage repair procedures.

Viable cartilage allograft outperforms existing treatments for focal knee cartilage defects

PURPOSE

Viable cartilage allograft (VCA) is a cartilage tissue matrix that contains cryopreserved viable allogeneic cartilage fibres. This study aimed to assess safety and benefits in treating focal knee cartilage defects with VCA. We hypothesized that VCA is a safe single-stage procedure in isolated chondral defects.

METHOD

In vitro analysis, in vivo studies and a prospective case series were performed. VCA was evaluated in a goat cartilage repair model. Symptomatic International Cartilage Repair Society grade 3/4A lesions of the femoral condyle or patella were implanted with VCA. International Knee Documentation Committee (IKDC), Knee injury and Osteoarthritis Outcome (KOOS) subscales, Lysholm, Short Form-12, Visual Analog Scale and pain frequency levels were assessed. Radiographic and magnetic resonance imaging (MRI) was performed at regular intervals postoperatively. Data were analysed by statisticians to determine the power and significance of the results.

RESULTS

The goat study confirmed that VCA is effective for cartilage repair. Twenty patients were implanted; the mean age was 28.1 (16-56), the mean body mass index (BMI) was 27.9 ± 5.6 and the mean follow-up was 24.1 months (range = 12.0-36.0 months). Lesions were in either the femoral condyle (7) or patella (13). Lesion sizes ranged from 1.5 to 6.0 cm2 (mean = 4.58 cm2 ). Outcome scores improved from preoperative baseline (POB): IKDC (78.2), Lysholm (89.0), KOOS: Pain (95.8), Symptoms (86.3), ADL (87.8), Sports (85.0) and QOL (75.0). MRI imaging demonstrated excellent osteochondral allograft assimilation. Second-look arthroscopy (two patients) demonstrated complete fill and incorporation (Brittberg scores 11/12). Functional scores were maintained at 24 (M): IKDC (86.24 ± 17.2), Lysholm (87.23 ± 15.0), KOOS: Pain (91.72 ± 17.3), Symptoms (84.92 ± 16.1), ADLs (93.80 ± 16.1), Sports (84.45 ± 27.7), QOL (81.30 ± 20.8).

CONCLUSION

VCA is an off-the-shelf, single-stage, conformable allogeneic graft that treats chondral defects with no additional fixation. Preclinical and short-term prospective clinical studies show that VCA can safely treat chondral defects with potential advantages to existing options.

LEVEL OF EVIDENCE

Level IV study.

The biomechanical and functional outcomes of autologous chondrocyte implantation for articular cartilage defects of the knee: A systematic review

PURPOSE

Autologous chondrocyte implantation (ACI) is primarily performed in active, young patients to treat knee pain and functional limitations resulting from articular cartilage injury. Nevertheless, the functional outcomes of ACI remain poorly understood. This systematic review aimed to evaluate the biomechanical and functional outcomes of ACI.

METHODS

Ovid MEDLINE, Embase, and Web of Science were systematically searched using the terms 'Knee OR Knee joint AND Autologous chondrocyte implantation OR ACI'. Inclusion and exclusion criteria were used to screen publications by title, abstract, and full text. Study quality and bias were assessed by two reviewers. Means and standard deviations of all collected variables were calculated and presented in the review.

PROSPERO ID

CRD42021238768.

RESULTS

Nineteen articles including 20 ACI cohorts were included. In general, the average range of motion (ROM) improved with clinical (>5°) and statistical significance (p < 0.05) postoperatively: 130.5 ± 14.8° to 136.1 ± 10.2°. Knee strength significantly improved within the first two postoperative years but remained poorer than control groups at final follow-up. No statistical differences were found between ACI and control groups in their ability to perform functional activities like the 6-minute walk test.

CONCLUSION

Knee range of motion generally improved following ACI. Although, some studies reported that knee strengths remained significantly poorer than healthy controls, particularly >2-years postoperatively, implying that longer-term strength training may benefit patients.However, the volume of research and current level of evidence remain low, thus further research is required to better understand the impact of ACI on knee function and guide future rehabilitative protocols.

Correlation between the quality of cartilage repair tissue and patellofemoral osteoarthritis after matrix-induced autologous chondrocyte implantation at three-year follow-up: a cross-sectional study

PURPOSE

To investigate whether the quality of cartilage repair tissue is associated with patellofemoral osteoarthritis (PFOA) at a three year follow-up after matrix-induced autologous chondrocyte implantation (MACI).

METHODS

This retrospective study included 32 patients who underwent MACI between October 2014 and May 2018 at our institute. The Lysholm score and Visual Analog Scale (VAS) score were assessed. The magnetic resonance observation of cartilage repair tissue (MOCART) 2.0 score and T2* relaxation time of repair tissue were used to evaluate cartilage repair tissue quality. A modified MRI Osteoarthritis Knee Score (mMOAKS) was used to evaluate PFOA.

RESULTS

Compared with pre-operative scores, the final Lysholm score (50.71 ± 2.22 vs 89.70 ± 1.18; t = 15.5, P < 0.0001) and VAS score (4.67 ± 0.47 vs 0.92 ± 0.64; t = 22.62, P < 0.0001) were improved at 3 years after MACI. At the three year follow-up, the mean MOCART 2.0 score was 61.56 ± 18.11, and the T2* relaxation time of the repair tissue was significantly lower than that in the healthy control region (24.11 ± 6.38 vs 34.39 ± 1.33, t =  - 8.635, P < 0.0001). The mean mMOAKS score was 9.16 ± 4.51. On univariate analysis, the MOCART 2.0 score and T2* relaxation time were negatively associated with the mMOAKS score.

CONCLUSION

MACI can lead to significant pain relief and restoration of knee joint function, and good quality cartilage repair tissue was a protective factor against PFOA at the three year follow-up.

Surgical strategies for chondral defects of the patellofemoral joint: a systematic review

BACKGROUND

The management of chondral defects of the patellofemoral joint is debated, and definitive evidence is lacking. This study systematically updated and summarised the current literature on the surgical management of isolated chondral defects of the patellofemoral joint, discussing techniques, outcome, pitfalls, and new frontiers.

METHODS

This systematic review was conducted according to the 2020 PRISMA statement. In August 2022, PubMed, Web of Science, Google Scholar, and Embase databases were accessed with no time constrain. All the clinical studies investigating the surgical management of chondral defects of the patellofemoral joint were retrieved. Articles which reported data on patients with advanced to severe osteoarthritis were not eligible. Only studies with a minimum 24 months follow-up were considered. Studies which mixed results of patellofemoral and tibiofemoral joints were not considered.

RESULTS

Data from 10 studies (692 procedures) were retrieved. The mean follow-up was 46.9 ± 18.2 months. The mean age of the patients was 34.0 ± 6.1 years, and the mean BMI was 25.9 ± 0.8 kg/m². The mean duration of symptoms before the index surgery was 81.0 ± 24.0 months. The mean defect size was 3.8 ± 0.8 cm². All the PROMs improved from baseline to last follow-up: VAS 0-10 (P = 0.04), Tegner (P = 0.02), Lysholm (P = 0.03), and International Knee Documentation Committee (P = 0.03). The rate of hypertrophy was 5.6% (14 of 251), the rate of progression to total knee arthroplasty was 2.4% (2 of 83), the rate of revision was 16.9% (29 of 136), and the rate of failure was 13.0% (16 of 123).

CONCLUSION

Current surgical strategies may be effective to improve symptoms deriving from chondral defects of the patellofemoral joint. The limited and heterogeneous data included for analysis impact negatively the results of the present study. Further clinical studies are strongly required to define surgical indications and outcomes, and the most suitable technique.

Prognostic factors for the management of chondral defects of the knee and ankle joint: a systematic review

Purpose

Different surgical techniques to manage cartilage defects are available, including microfracture (MFx), autologous chondrocyte implantation (ACI), osteoarticular auto- or allograft transplantation (OAT), autologous matrix-induced chondrogenesis (AMIC). This study investigated the patient-related prognostic factors on the clinical outcomes of surgically treated knee and ankle cartilage defects.

Methods

This study followed the PRISMA statement. In May 2022, the following databases were accessed: PubMed, Google Scholar, Embase, and Scopus. All the studies investigating the outcomes of surgical management for knee and/or talus chondral defects were accessed. Only studies performing mesenchymal stem cells transplantation, OAT, MFx, ACI, and AMIC were considered. A multiple linear model regression analysis through the Pearson Product–Moment Correlation Coefficient was used.

Results

Data from 184 articles (8905 procedures) were retrieved. Female sex showed a positive moderate association with visual analogue scale at last follow-up (P = 0.02). Patient age had a negative association with the American Orthopaedic Foot and Ankle Score (P = 0.04) and Lysholm Knee Scoring Scale (P = 0.03). BMI was strongly associated with graft hypertrophy (P = 0.01). Greater values of VAS at baseline negatively correlate with lower values of Tegner Activity Scale at last follow-up (P < 0.0001).

Conclusion

The clinical outcomes were mostly related to the patients’ performance status prior surgery. A greater BMI was associated with greater rate of hypertrophy. Female sex and older age evidenced fair influence, while symptom duration prior to the surgical intervention and cartilage defect size evidenced no association with the surgical outcome. Lesion size and symptom duration did not evidence any association with the surgical outcome.

Fixation of the Membrane during Matrix-Induced Autologous Chondrocyte Implantation in the Knee: A Systematic Review

Introduction: It is unclear whether the type of membrane used for matrix-assisted autologous chondrocyte implantation (mACI) influences results. A systematic review was conducted to investigate the midterm results of the three most common types of membrane fixation for mACI. Methods: This systematic review was conducted according to the 2020 PRISMA checklist. PubMed, Google Scholar, Embase, and Scopus online databases were accessed in August 2022. All the prospective clinical trials reporting outcomes of mACI in the knee were considered. Studies that describe the modality of membrane fixation (glued, glued, and sutured, no fixation) used for mACI were eligible. Studies that conducted a minimum of 12 months of follow-up were considered. The outcomes of interest were the Tegner Activity Scale and International Knee Documentation Committee (IKDC) score. The rate of failure and revisions were also collected. Results: Data from 26 studies (1539 procedures; 554 of 1539 (36%) were women) were retrieved. The mean follow-up was 42.6 (12 to 84) months. No difference between the groups was found in terms of mean duration of symptoms, age, BMI, gender, and defect size (P > 0.1). No difference was found in terms of the Tegner score (P = 0.3). When no fixation was used, a statistically significant higher IKDC compared to the other groups (P = 0.02) was evidenced. No difference was found in the rate of failure (P = 0.1). The no-fixation group evidenced a statistically significant lower rate of revisions (P = 0.02). Conclusions: No membrane fixation for mACI in the knee scored better than the fastening techniques at the midterm follow-up.

Good healing potential of patellar chondral defects after all-arthroscopic autologous chondrocyte implantation with spheroids: a second-look arthroscopic assessment

PURPOSE

To report second-look arthroscopic assessment after all-arthroscopic autologous chondrocyte implantation (ACI) for articular cartilage defects at the patella.

METHODS

A second-look arthroscopy after all-arthroscopic ACI using chondrospheres^® (ACT3D) was performed in 30 patients with 30 full-thickness retropatellar cartilage defects. The mean time from ACI to second-look arthroscopy was 14.9 ± 16.3 (6-71) months. The quality of cartilage regeneration was evaluated by the International Cartilage-Repair Score (ICRS)-Cartilage Repair Assessment (CRA).

RESULTS

Eleven lesions (36.7%) were classified as CRA grade I (normal) and 19 lesions (63.3%) as grade II (nearly normal). Concerning the degree of defect repair, 25 lesions (83.3%) were repaired up to the height of the surrounding articular retropatellar cartilage. Five lesions (16.7%) showed 75% repair of defect depth. The border zone was completely integrated into the surrounding articular cartilage shoulder in 28 lesions (93.3%) and demarcated within 1 mm in 2 lesions (6.7%). Macroscopically and by probing, 12 lesions (40%) had intact smooth surface, 17 lesions (56.7%) had fibrillated surface and 1 lesion (3.3%) had small, scattered fissures. A negative correlation was found between the overall repair assessment score and the defect size (r² = - 0.430, p = 0.046) and between integration into border zone and defect size (r² = - 0.340, p = 0.045). A positive correlation was found between macroscopic appearance and age (r² =  + 0.384, p = 0.036).

CONCLUSIONS

All-arthroscopic ACI using chondrospheres^® (ACT3D) for full-thickness retropatellar articular cartilage defects proved to be reproducible and reliable. The advantage of the procedure is that it is minimal invasive. Arthroscopic second-look demonstrated a high grade of normal or nearly normal cartilage regeneration. Although statistically significant differences were not observed, larger defect size and younger age may compromise the result of overall repair.

LEVEL OF EVIDENCE

III.

Particulated Juvenile Articular Cartilage and Matrix-Induced Autologous Chondrocyte Implantation Are Cost-Effective for Patellar Chondral Lesions

PURPOSE

To compare the cost-effectiveness of nonoperative management, particulated juvenile allograft cartilage (PJAC), and matrix-induced autologous chondrocyte implantation (MACI) in the management of patellar chondral lesions.

METHODS

A Markov model was used to evaluate the cost-effectiveness of three strategies for symptomatic patellar chondral lesions: 1) nonoperative management, 2) PJAC, and 3) MACI. Model inputs (transition probabilities, utilities, and costs) were derived from literature review and an institutional cohort of 67 patients treated with PJAC for patellar chondral defects (mean age 26 years, mean lesion size 2.7 cm²). Societal and payer perspectives over a 15-year time horizon were evaluated. The principal outcome measure was the incremental cost-effectiveness ratio (ICER) using a $100,000/quality-adjusted life year (QALY) willingness-to-pay threshold. Sensitivity analyses were performed to assess the robustness of the model and the relative effects of variable estimates on base case conclusions.

RESULTS

From a societal perspective, nonoperative management, PJAC, and MACI cost $4,140, $52,683, and $83,073 and were associated with 5.28, 7.22, and 6.92 QALYs gained, respectively. PJAC and MACI were cost-effective relative to nonoperative management (ICERs $25,010/QALY and $48,344/QALY, respectively). PJAC dominated MACI in the base case analysis by being cheaper and more effective, but this was sensitive to the estimated effectiveness of both strategies. PJAC remained cost-effective if PJAC and MACI were considered equally effective.

CONCLUSIONS

In the management of symptomatic patellar cartilage defects, PJAC and MACI were both cost-effective compared to nonoperative management. Because of the need for one surgery instead of two, and less costly graft material, PJAC was cheaper than MACI. Consequently, when PJAC and MACI were considered equally effective, PJAC was more cost-effective than MACI. Sensitivity analyses accounting for the lack of robust long-term data for PJAC or MACI demonstrated that the cost-effectiveness of PJAC versus MACI depended heavily on the relative probabilities of yielding similar clinical results.

LEVEL OF EVIDENCE

III, economic and decision analysis.

Matrix-induced autologous chondrocyte implantation (mACI) versus autologous matrix-induced chondrogenesis (AMIC) for chondral defects of the knee: a systematic review

INTRODUCTION

Chondral defects of the knee are common and their treatment is challenging.

SOURCE OF DATA

PubMed, Google scholar, Embase and Scopus databases.

AREAS OF AGREEMENT

Both autologous matrix-induced chondrogenesis (AMIC) and membrane-induced autologous chondrocyte implantation (mACI) have been used to manage chondral defects of the knee.

AREAS OF CONTROVERSY

It is debated whether AMIC and mACI provide equivalent outcomes for the management of chondral defects in the knee at midterm follow-up. Despite the large number of clinical studies, the optimal treatment is still controversial.

GROWING POINTS

To investigate whether AMIC provide superior outcomes than mACI at midterm follow-up.

AREAS TIMELY FOR DEVELOPING RESEARCH

AMIC may provide better outcomes than mACI for chondral defects of the knee. Further studies are required to verify these results in a clinical setting.

Membrane scaffolds for matrix-induced autologous chondrocyte implantation in the knee: a systematic review

INTRODUCTION

Chondral defects of the knee are common and their management is challenging.

SOURCE OF DATA

Current scientific literature published in PubMed, Google scholar, Embase and Scopus.

AREAS OF AGREEMENT

Membrane-induced autologous chondrocyte implantation (mACI) has been used to manage chondral defects of the knee.

AREAS OF CONTROVERSY

Hyaluronic acid membrane provides better outcomes than a collagenic membrane for mACI in the knee at midterm follow-up is controversial.

GROWING POINTS

To investigate whether hyaluronic acid membrane may provide comparable clinical outcomes than collagenic membranes for mACI in focal defects of the knee.

AREAS TIMELY FOR DEVELOPING RESEARCH

Hyaluronic acid membrane yields a lower rate of failures and revision surgeries for mACI in the management of focal articular cartilage defects of the knee compared with collagenic scaffolds at midterm follow-up. No difference was found in patient reported outcome measures (PROMs). Further comparative studies are required to validate these results in a clinical setting.

Treatment of Patellofemoral Chondral Lesions Using Microfractures Associated with a Chitosan Scaffold: Mid-Term Clinical and Radiological Results

OBJECTIVE

To assess the clinical and radiological results of patellofemoral osteochondral lesions treated with microfractures associated with a chitosan scaffold.

DESIGN

A retrospective observational analytical study was performed. Fifteen patients with full-thickness patellofemoral osteochondral lesions were included. Quantity and quality of the reparation cartilage was assessed with the MOCART 2.0 score on a postoperative magnetic resonance imaging (MRI), and clinical outcomes were evaluated with pre- and postoperative Kujala score tests. Shapiro-Wilk test for normality was applied as well as Wilcoxon's signed rank test and Kruskal-Wallis H test for clinical scores within subjects and patella versus trochlea subgroups comparisons. Analysis of variance test was used for imaging subgroups comparison, with P < 0.05 defined as statistical significance.

RESULTS

Mean follow-up was 33.36 months (range 24-60 months). Postoperative Kujala scores improved an average of 19 points compared with the preoperative state (SE = 17.6; P < 0.001). No statistical difference was found through the clinical location assessment (P = 0.756), as well as the cartilage imaging assessment (P = 0.756). The mean MOCART 2.0 scale was 67.67 (range 50-85).

CONCLUSIONS

Treating full-thickness patellofemoral osteochondral lesions with microfractures associated with a chitosan scaffold proved to be effective regarding defect filling and symptomatic improvement.

Typical MRI-pattern suggests peak maturation of the ACI graft 2 years after third-generation ACI: a systematic review

PURPOSE

The purpose of the present article was (1) to systematically review the current literature and (2) to collect data regarding the postoperative magnetic resonance imaging (MRI) appearance of third-generation autologous chondrocyte implantation (ACI) grafts and (3) to provide an overview of imaging findings at various postoperative time points.

METHODS

A systematic review of the literature in Medline (Pubmed) and Embase was performed using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Articles which reported the post-operative MRI morphological outcomes following the use of third-generation ACI for treatment of knee cartilage lesions were included. All MRI results were allocated to six different time intervals: ≤ 3 months, > 3-6 months, > 6 months-1 year, > 1 year-2 years, > 2-5 years and > 5 years after surgery.

RESULTS

A total of 22 studies were included and the study populations ranged from 13 to 180 patients adding up to a total of 951 patients. Parameters such as defect fill, border integration, surface contour, graft morphology and integrity of the subchondral lamina all improve gradually with a peak two years following surgery suggesting complete graft maturation at this time point. After this peak, a statistically insignificant decline is noted for most of the parameters. Signal intensity was found to gradually shift from hyperintense to isointense in the first 36 months and to hypointense later on. Contrarily, subchondral bone edema is not only a postoperative feature of the procedure but also can reappear or persist up to ten years after surgery. As graft failures can appear after two years, consequently, the MRI composite score is also affected.

CONCLUSION

Recurring patterns in postoperative MRI appearance were observed in certain parameters including defect filling, graft signal intensity and structure, border integration of the graft while parameters like subchondral bone tend to be unpredictable. Given the heterogenous findings in terms of clinical correlation, and relating that aspect to the patterns found in this review, an MRI is justified at three months, one year, two years and five years after surgery, unless the clinical symptomatology and individual patient needs dictate otherwise.

LEVEL OF EVIDENCE

IV.

Surgical management of focal chondral defects of the knee: a Bayesian network meta-analysis

Background

Focal chondral defects of the knee are common. Several surgical techniques have been proposed for the management of chondral defects: microfractures (MFX), osteochondral autograft transplantation (OAT), autologous matrix-induced chondrogenesis (AMIC) and autologous chondrocyte implantation (ACI)—first generation (pACI), second generation (cACI) and third generation (mACI). A Bayesian network meta-analysis was conducted to compare these surgical strategies for chondral defects in knee at midterm follow-up.

Methods

This Bayesian network meta-analysis was conducted according to the PRISMA extension statement for reporting of systematic reviews incorporating network meta-analyses of health care interventions. PubMed, Google Scholar, Embase and Scopus databases were accessed in July 2021. All the prospective comparative clinical trials investigating two or more surgical interventions for chondral defects of the knee were accessed. The network meta-analyses were performed through a Bayesian hierarchical random-effects model analysis. The log odds ratio (LOR) effect measures were used for dichotomic variables, while the standardized mean difference (SMD) for the continuous variables.

Results

Data from 2220 procedures (36 articles) were retrieved. The median follow-up was 36 (24 to 60) months. The ANOVA test found good baseline comparability between symptoms duration, age, sex and body mass index. AMIC resulted in higher Lysholm score (SMD 3.97) and Tegner score (SMD 2.10). AMIC demonstrated the lowest rate of failures (LOR −0.22) and the lowest rate of revisions (LOR 0.89). As expected, MFX reported the lower rate of hypertrophy (LOR −0.17) followed by AMIC (LOR 0.21). No statistically significant inconsistency was found in the comparisons.

Conclusion

AMIC procedure for focal chondral defects of the knee performed better overall at approximately 3 years’ follow-up.

Thoughts on cartilage tissue engineering: A 21st century perspective

In mature individuals, hyaline cartilage demonstrates a poor intrinsic capacity for repair, thus even minor defects could result in progressive degeneration, impeding quality of life. Although numerous attempts have been made over the past years for the advancement of effective treatments, significant challenges still remain regarding the translation of in vitro cartilage engineering strategies from bench to bedside. This paper reviews the latest concepts on engineering cartilage tissue in view of biomaterial scaffolds, tissue biofabrication, mechanobiology, as well as preclinical studies in different animal models. The current work is not meant to provide a methodical review, rather a perspective of where the field is currently focusing and what are the requirements for bridging the gap between laboratory-based research and clinical applications, in light of the current state-of-the-art literature. While remarkable progress has been accomplished over the last 20 years, the current sophisticated strategies have reached their limit to further enhance healthcare outcomes. Considering a clinical aspect together with expertise in mechanobiology, biomaterial science and biofabrication methods, will aid to deal with the current challenges and will present a milestone for the furtherance of functional cartilage engineering.

Clinical and Radiographic Outcomes After Treatment of Patellar Chondral Defects: A Systematic Review

CONTEXT

There is currently no evidence-based consensus on how to treat a full-thickness, symptomatic articular cartilage injury of the patella, although numerous treatment options are available.

OBJECTIVE

To systematically evaluate the functional outcomes after operative treatment of patellar cartilage lesions. Our secondary purpose was to evaluate radiographic outcomes after treatment.

DATA SOURCES

PubMed, Cochrane, and Embase.

STUDY SELECTION

Studies published between January 1, 1990 and December 31, 2018 that included patient-reported functional outcomes for patients after operative treatment of patellar chondral defects at a minimum 2-year follow-up were included.

STUDY DESIGN

Systematic review.

LEVEL OF EVIDENCE

Level 4.

DATA EXTRACTION

MINORS (Methodological Index for Non-Randomized Studies) score, level of evidence, sample size, demographic data, follow-up data, intervention, functional outcome scores, and magnetic resonance imaging (MRI) data were collected.

RESULTS

The review identified 10 studies and 293 patients receiving cartilage restoration procedures for patellar chondral defects with extractable clinical and radiographic results and data on complications and reoperations. All treatments (autologous chondrocyte implantation [ACI], matrix-induced ACI [MACI], autologous osteochondral transplantation [AOT]) utilized in the management of patellar chondral lesions, with the exception of isolated particulated juvenile articular cartilage, demonstrated statistically significant improvements in functional outcome scores compared with preoperative measurements at a minimum of 2-year follow-up. Postoperative MRIs were obtained in 6 studies and found that regardless of treatment, moderate-to-complete infill of patellar cartilage lesions was seen in the majority of patients. While failure rates were low for the various treatment modalities, rates of reoperation were substantial, with up to 40% to 60% reoperation rate seen after ACI.

CONCLUSION

Patients treated with ACI, MACI, and AOT all demonstrated statistically significant improvements in functional outcome scores with radiographic evidence of healing at minimum of 2-year follow-up. Evidence is insufficient to recommend one particular treatment over another.

Management of Patellar Chondral Defects with Autologous Matrix Induced Chondrogenesis (AMIC) Compared to Microfractures: A Four Years Follow-Up Clinical Trial

Introduction: Evidence on the management of chondral defects of the patella arises from studies in which the patellofemoral joint was treated together with the femorotibial joint and primary and revision settings. Furthermore, the superiority of Autologous Matrix Induced Chondrogenesis (AMIC) over microfractures (MFx) for patellar chondral defects is uncertain. Therefore, the present study compared primary isolated AMIC versus MFx for focal unipolar chondral defects of the patellar facet joints at midterm follow-up. Methods: Patients undergoing AMIC or isolated MFx surgery for borderline-sized focal unipolar chondral defects of the patellar facet joints were followed at our institution. All surgeries were performed in the same fashion by experienced surgeons. A parapatellar arthrotomy was adopted in all surgeries. The outcomes of interest were: Visual Analogic Scale (VAS), Tegner Activity Scale, International Knee Documentation Committee (IKDC), and the Lysholm scores. The Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) was assessed by a blinded radiologist, who had not been involved in the clinical management of the patients. Results: 38 patients were enrolled in the present study: 27 underwent AMIC, and 11 MFx. The mean follow-up was 45.1 months. The mean age of the patients at baseline was 34.5 years. The mean size of the defect was 2.6 cm². The MFx cohort experienced a shorter length of the hospitalization (P = 0.008). There was no difference in terms of follow-up and previous symptoms duration, mean age, sex, side, defect size, and BMI. At last follow-up, the AMIC cohort reported greater IKDC (P = 0.01), Lysholm (P = 0.009), and Tegner (P = 0.02), along with a low rate of failure (P = 0.02). VAS was lower in the AMIC group (P = 0.002). No difference was found in the MOCART score (P = 0.09), rates of revision (P = 0.06), and arthroplasty (P = 0.2). Conclusion: The AMIC procedure achieves greater IKDC and Lysholm score, and a significant reduction of the VAS score in the management of patellar chondral defects. The Tegner scale demonstrated greater activity after AMIC procedure. Finally, the AMIC group evidenced a lower rate of failure. Similarity was found on MOCART score, rates of revision, and arthroplasty between the two procedures.

[Expert consensus on surgical treatment of patellofemoral osteoarthritis]

Patellofemoral osteoarthritis (PFOA) is one of the most common causes of anterior knee pain in middle-aged and elderly population. In general, elementary therapy and drug therapy are the preferred choices for PFOA management. However, for those who cannot achieve satisfactory effectiveness with standard non-surgical treatment, surgical therapy stands as an alternative treatment. The surgical therapy includes repair surgery and reconstruction surgery. The choice of surgical plans for PFOA management mainly depends on the etiology, pathogenesis, location, and severity of the lesions. To aid clinical decision-making, the National Clinical Research Center for Geriatric Disorders (Xiangya Hospital) and the Joint Surgery Branch of the Chinese Orthopedic Association arranged nationwide orthopedic specialists to set up a work panel. After reviewing the research progress of surgical therapy and the latest guidelines and consensus for PFOA management, the work panel discussed repeatedly to reach this consensus. The present consensus aims to provide valid evidences for clinical practices of the surgical therapy of PFOA, so as to avoid inappropriate and irregular treatment behaviors, reduce surgical trauma, improve surgical efficacy and the quality of life, and to ease the burden of PFOA.

HA-g-CS Implant and Moderate-intensity Exercise Stimulate Subchondral Bone Remodeling and Promote Repair of Osteochondral Defects in Mice

Background: Substantial evidence shows that crosstalk between cartilage and subchondral bone may play an important role in cartilage repair. Animal models have shown that hydroxyapatite-grafted-chitosan implant (HA-g-CS) and moderate-intensity exercise promote regeneration of osteochondral defects. However, no in vivo studies have demonstrated that these two factors may have a synergistic activity to facilitate subchondral bone remodeling in mice, thus supporting bone-cartilage repair. Questions: This study was to clarify whether HA-g-CS and moderate-intensity exercise might have a synergistic effect on facilitating (1) regeneration of osteochondral defects and (2) subchondral bone remodeling in a mouse model of osteochondral defects. Methods: Mouse models of osteochondral defects were created and divided into four groups. BC Group was subjected to no treatment, HC Group to HA-g-CS implantation into osteochondral defects, ME group to moderate-intensity treadmill running exercise, and HC+ME group to both HA-g-CS implantation and moderate-intensity exercise until sacrifice. Extent of subchondral bone remodeling at the injury site and subsequent cartilage repair were assessed at 4 weeks after surgery. Results: Compared with BC group, HC, ME and HC+ME groups showed more cartilage repair and thicker articular cartilage layers and HC+ME group acquired the best results. The extent of cartilage repair was correlated positively to bone formation activity at the injured site as verified by microCT and correlation analysis. Histology and immunofluorescence staining confirmed that bone remodeling activity was increased in HC and ME groups, and especially in HC+ME group. This bone formation process was accompanied by an increase in osteogenesis and chondrogenesis factors at the injury site which promoted cartilage repair. Conclusions: In a mouse model of osteochondral repair, HA-g-CS implant and moderate-intensity exercise may have a synergistic effect on improving osteochondral repair potentially through promotion of subchondral bone remodeling and generation of osteogenesis and chondrogenesis factors. Clinical Relevance: Combination of HA-g-CS implantation and moderate-intensity exercise may be considered potentially in clinic to promote osteochondral defect repair. Also, cartilage and subchondral bone forms a functional unit in an articular joint and subchondral bone may regulate cartilage repair by secreting growth factors in its remodeling process. However, a deeper insight into the exact role of HA-g-CS implantation and moderate-intensity exercise in promoting osteochondral repair in other animal models should be explored before they can be applied in clinic in the future.

Sporting participation following the operative management of chondral defects of the knee at mid-term follow up: a systematic review and meta-analysis

PURPOSE

The purpose of this study was to perform a systematic review of the reparticipation in sport at mid-term follow up in athletes who underwent biologic treatment of chondral defects in the knee and compare the rates amongst different biologic procedures.

METHODS

A search of PubMed/Medline and Embase was performed in May 2020 in keeping with Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. The criteria for inclusion were observational, published research articles studying the outcomes and rates of participation in sport following biologic treatments of the knee with a minimum mean/median follow up of 5 years. Interventions included microfracture, osteochondral autograft transfer (OAT), autologous chondrocyte implantation (ACI), matrix-induced autologous chondrocyte implantation (MACI), osteochondral allograft, or platelet rich plasma (PRP) and peripheral blood stem cells (PBSC). A random effects model of head-to-head evidence was used to determine rates of sporting participation following each intervention.

RESULTS

There were twenty-nine studies which met the inclusion criteria with a total of 1276 patients (67% male, 33% female). The mean age was 32.8 years (13-69, SD 5.7) and the mean follow up was 89 months (SD 42.4). The number of studies reporting OAT was 8 (27.6%), ACI was 6 (20.7%), MACI was 7 (24.1%), microfracture was 5 (17.2%), osteochondral allograft was 4 (13.8%), and one study (3.4%) reported on PRP and PBSC. The overall return to any level of sport was 80%, with 58.6% returning to preinjury levels. PRP and PBSC (100%) and OAT (84.4%) had the highest rates of sporting participation, followed by allograft (83.9%) and ACI (80.7%). The lowest rates of participation were seen following MACI (74%) and microfracture (64.2%).

CONCLUSIONS

High rates of re-participation in sport are sustained for at least 5 years following biologic intervention for chondral injuries in the knee. Where possible, OAT should be considered as the treatment of choice when prolonged participation in sport is a priority for patients. However, MACI may achieve the highest probability of returning to the same pre-injury sporting level.

LEVEL OF EVIDENCE

IV.

Patellofemoral Cartilage Restoration: A Systematic Review and Meta-analysis of Clinical Outcomes

BACKGROUND

Many surgical options for treating patellofemoral (PF) cartilage lesions are available but with limited evidence comparing their results.

PURPOSE

To determine and compare outcomes of PF cartilage restoration techniques.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

PRISMA (Preferred Reporting Items for Systematic Meta-Analyses) guidelines were followed by utilizing the PubMed, EMBASE, and Cochrane Library databases. Inclusion criteria were clinical studies in the English language, patient-reported outcomes after PF cartilage restoration surgery, and >12 months' follow-up. Quality assessment was performed with the Coleman Methodology Score. Techniques were grouped as osteochondral allograft transplantation (OCA), osteochondral autograft transfer (OAT), chondrocyte cell-based therapy, bone marrow-based therapy, and scaffolds.

RESULTS

A total of 59 articles were included. The mean Coleman Methodology Score was 71.8. There were 1937 lesions (1077 patellar, 390 trochlear, and 172 bipolar; 298 unspecified). The frequency of the procedures was as follows, in descending order: chondrocyte cell-based therapy (65.7%), bone marrow-based therapy (17.2%), OAT (8%), OCA (6.6%), and scaffolds (2.2%). When compared with the overall pooled lesion size (3.9 cm²; 95% CI, 3.5-4.3 cm²), scaffold (2.2 cm²; 95% CI, 1.8-2.5 cm²) and OAT (1.5 cm²; 95% CI, 1.1-1.9 cm²) lesions were smaller (P < .001), while chondrocyte cell-based therapy lesions were larger (4.7 cm²; 95% CI, 4.1-5.3 cm²; P = .039). Overall, the instability pool was 11.9%, and the anatomic risk factors pool was 32.1%. Statistically significant improvement was observed on at least 1 patient-reported outcome in chondrocyte cell-based therapy (83%), OAT (78%), OCA (71%), bone marrow-based therapy (64%), and scaffolds (50%). There were no significant differences between any group and the overall pooled change in International Knee Documentation Committee score (30.2; 95% CI, 27.4-32.9) and Lysholm score (25.2; 95% CI, 16.9-33.5). There were no significant differences between any group and the overall pooled rate in minor complication rate (7.6%; 95% CI, 4.7%-11.9%) and major complication rate (8.3%; 95% CI, 5.7%-12.0%); however, OCA had a significantly greater failure rate (22.7%; 95% CI, 14.6%-33.4%) as compared with the overall rate (6.8%; 95% CI, 4.7%-9.5%).

CONCLUSION

PF cartilage restoration leads to improved clinical outcomes, with low rates of minor and major complications. There was no difference among techniques; however, failures were higher with OCA.

Surgical and tissue engineering strategies for articular cartilage and meniscus repair

Injuries to articular cartilage and menisci can lead to cartilage degeneration that ultimately results in arthritis. Different forms of arthritis affect ~50 million people in the USA alone, and it is therefore crucial to identify methods that will halt or slow the progression to arthritis, starting with the initiating events of cartilage and meniscus defects. The surgical approaches in current use have a limited capacity for tissue regeneration and yield only short-term relief of symptoms. Tissue engineering approaches are emerging as alternatives to current surgical methods for cartilage and meniscus repair. Several cell-based and tissue-engineered products are currently in clinical trials for cartilage lesions and meniscal tears, opening new avenues for cartilage and meniscus regeneration. This Review provides a summary of surgical techniques, including tissue-engineered products, that are currently in clinical use, as well as a discussion of state-of-the-art tissue engineering strategies and technologies that are being developed for use in articular cartilage and meniscus repair and regeneration. The obstacles to clinical translation of these strategies are also included to inform the development of innovative tissue engineering approaches.

Changing trends in the use of cartilage restoration techniques for the patellofemoral joint: a systematic review

PURPOSE

The patellofemoral (PF) joint contains the thickest articular cartilage in the human body. Chondral lesions to this area are often misdiagnosed and can predispose to secondary osteoarthritis if left untreated. Treatment options range from arthroscopic debridement to cartilage restoration techniques such as microfracture (MFx), autologous chondrocyte implantation (ACI), and osteochondral autograft transplantation. The purpose of this study was to systematically assess the trends in surgical techniques, outcomes, and complications of cartilage restoration of the PF joint.

METHODS

This review has been conducted according to the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). The electronic databases PubMed, MEDLINE, and EMBASE were searched from January 1, 2007 to April 30, 2018. The Methodological Index for Non-randomized Studies (MINORS) was used to assess study quality. A two-proportion z test was used to determine whether the differences between the proportions of cartilage restoration techniques used from 2007 to 2012 and 2013-2018 were statistically significant.

RESULTS

Overall, 28 studies were identified, including 708 patients (824 knees) with a mean age of 39.5 ± 10.5 years and a mean follow-up of 39.1 ± 16.0 months. Majority of patients were treated with ACI (45.5%) and MFx (29.6%). A significant increase in the use of the third generation ACI occurred with a simultaneous decreased usage of the conventional MFx over the last 5 years (p < 0.001). All techniques had significant (p < 0.05) improvements in clinical outcomes. The overall complication rate was 9.2%, of which graft hypertrophy (2.7%) was the most prevalent.

CONCLUSIONS

ACI was the most common restoration technique. The use of third generation ACI has increased with a concurrent decline in the use of conventional MFx over the latter half of the past decade (p < 0.001). Overall, the various cartilage restoration techniques reported improvements in patient reported outcomes with low complication rates. Definitive conclusions on the optimal treatment remain elusive due to a lack of high-quality comparative studies.

LEVEL OF EVIDENCE

Level IV, Systematic Review of Level-II-IV studies.

Patellofemoral Arthroplasty

Background

Patellofemoral arthritis is a common cause of anterior knee pain and limits flexion-related activities of daily living and exercise. While frequently present in bicompartmental and tricompartmental osteoarthritis, patellofemoral arthritis can occur in isolation. Patellofemoral arthroplasty as a treatment option is gaining in popularity, especially with new implant designs. We report a case in which new inlay implants were used to resurface the patellofemoral joint in a patient with contralateral compromise secondary to a previous below-knee amputation.

Case Report

A 37-year-old female with a contralateral right below-knee amputation and progressive left patellofemoral arthritis had failed multiple conservative treatment modalities. She underwent isolated patellofemoral arthroplasty using an inlay-designed implant. The patient was followed for 2 years postoperatively. She noticed an immediate increase in her knee range of motion and her pain scores improved. Two years postoperatively, she demonstrated drastic improvement in all outcome measures: International Knee Documentation Committee score (16.1 to 88.5), Lysholm Knee Scoring Scale (22 to 100), Knee Injury and Osteoarthritis Outcome Score (KOOS) Symptoms (7.14 to 96.43), KOOS Pain (2.78 to 100), KOOS Activities of Daily Living (0 to 100), KOOS Sports (0 to 100), and KOOS Quality of Life (12.5 to 93.75).

Conclusion

Inlay patellofemoral arthroplasty is a valid treatment option for isolated patellofemoral arthritis. Successful results can be achieved with this procedure after failure of conservative measures in patients with limited or no evidence of tibiofemoral arthritis.

A Comparison of 2-Year Outcomes in Patients Undergoing Tibiofemoral or Patellofemoral Matrix-Induced Autologous Chondrocyte Implantation

BACKGROUND

Matrix-induced autologous chondrocyte implantation (MACI) has demonstrated encouraging clinical results in the treatment of knee chondral defects. However, earlier studies suggested that chondrocyte implantation in the patellofemoral (PF) joint was less effective than in the tibiofemoral (TF) joint.

PURPOSE

To compare the radiological and clinical outcomes of those undergoing MACI to either the femoral condyles or PF joint.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 194 patients were included in this analysis, including 127 undergoing MACI to the medial (n = 94) and lateral (n = 33) femoral condyle, as well as 67 to the patella (n = 35) or trochlea (n = 32). All patients were evaluated clinically (Knee injury and Osteoarthritis Outcome Score [KOOS], visual analog scale, Short Form-36) before surgery and at 3, 12, and 24 months after surgery, while magnetic resonance imaging (MRI) was undertaken at 3, 12, and 24 months, with the MOCART (magnetic resonance observation of cartilage repair tissue) scoring system employed to evaluate the quality and quantity of repair tissue, as well as an MRI composite score. Patient satisfaction was evaluated.

RESULTS

No significant group differences ( P > .05) were seen in demographics, defect size, prior injury, or surgical history, while the majority of clinical scores were similar preoperatively. All clinical scores significantly improved over time ( P < .05), with a significant group effect observed for KOOS activities of daily living ( P = .008), quality of life ( P = .008), and sport ( P = .017), reflecting better postoperative scores in the TF group. While the PF group had significantly lower values at baseline for the KOOS activities of daily living and quality of life subscales, it actually displayed a similar net improvement over time compared with the TF group. At 24 months, 93.7% (n = 119) and 91.0% (n = 61) of patients were satisfied with the ability of MACI to relieve their knee pain, 74.0% (n = 94) and 65.7% (n = 44) with their ability to participate in sport, and 90.5% (n = 115) and 83.6% (n = 56) satisfied overall, in the TF and PF groups, respectively. MRI evaluation via the MOCART score revealed a significant time effect ( P < .05) for the MRI composite score and graft infill over the 24-month period. While subchondral lamina scored significantly better ( P = .002) in the TF group, subchondral bone scored significantly worse ( P < .001). At 24 months, the overall MRI composite score was classified as good/excellent in 98 TF patients (77%) and 54 PF patients (81%).

CONCLUSION

MACI in the PF joint with concurrent correction of PF maltracking if required leads to similar clinical and radiological outcomes compared with MACI on the femoral condyles.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

IV.

Patellofemoral pain in athletes

Patellofemoral pain (PFP) is a frequent cause of anterior knee pain in athletes, which affects patients with and without structural patellofemoral joint (PFJ) damage. Most younger patients do not have any structural changes to the PFJ, such as an increased Q angle and a cartilage damage. This clinical entity is known as patellofemoral pain syndrome (PFPS). Older patients usually present with signs of patellofemoral osteoarthritis (PFOA). A key factor in PFPS development is dynamic valgus of the lower extremity, which leads to lateral patellar maltracking. Causes of dynamic valgus include weak hip muscles and rearfoot eversion with pes pronatus valgus. These factors can also be observed in patients with PFOA. The available evidence suggests that patients with PFP are best managed with a tailored, multimodal, nonoperative treatment program that includes short-term pain relief with nonsteroidal anti-inflammatory drugs (NSAIDs), passive correction of patellar maltracking with medially directed tape or braces, correction of the dynamic valgus with exercise programs that target the muscles of the lower extremity, hip, and trunk, and the use of foot orthoses in patients with additional foot abnormalities.

Cartilage Restoration Techniques for the Patellofemoral Joint

Symptomatic osteochondral lesions of the patellofemoral joint are clinically challenging to manage because of the limited healing potential of articular cartilage; the complex morphology of the patellofemoral joint; the heterogeneity of the articular surface between patients; and high stresses across the joint, which can be altered by malalignment, tilt, or maltracking. Indications for surgery include traumatic lesions, osteochondritis dissecans, and high-grade chondromalacia in association with persistent pain despite a course of nonsurgical management. Various techniques have been described for managing symptomatic osteochondral lesions of the patellofemoral joint, including microfracture, osteochondral autograft transplantation, and biologic cell transplantation, including autologous chondrocyte implantation. Salvage techniques (eg, fresh allograft) may provide satisfactory outcomes after a failed attempt at surgical management. Irrespective of the surgical technique used, outcomes are generally worse in the patellofemoral compartment than in the tibiofemoral joint. The concomitant management of associated pathology, including patellar malalignment, is recommended because it has been shown to improve the success of cartilage restoration procedures.

Clinical Outcomes After Autologous Chondrocyte Implantation in Adolescents' Knees: A Systematic Review

PURPOSE

To perform a systematic review of the use of autologous chondrocyte implantation (ACI) in the adolescent knee.

SPECIFIC AIMS

(1) quantify clinical outcomes of ACI in adolescent knees, (2) identify lesion and patient factors that correlate with clinical outcome, and (3) determine the incidence of complications of ACI in adolescents.

METHODS

PubMed, MEDLINE, SCOPUS, CINAHL, and Cochrane Collaboration Library databases were searched systematically. Outcome scores recorded included the International Knee Documentation Committee score, the International Cartilage Repair Society score, the Knee Injury and Osteoarthritis Outcome Score, the visual analog scale, the Bentley Functional Rating Score, the Modified Cincinnati Rating System, Tegner activity Lysholm scores, and return athletics. Outcome scores were compared among studies based on proportion of adolescents achieving specific outcome quartiles at a minimum 1-year follow-up. Methodologic quality of studies was evaluated by Coleman Methodology Scores (CMSs).

RESULTS

Five studies reported on 115 subjects who underwent ACI with periosteal cover (ACI-P; 95, 83%), ACI with type I/type III collagen cover (ACI-C; 6, 5%), or matrix-induced ACI (MACI; 14, 12%). Mean patient age was 16.2 years (range, 11 to 21 years). All studies were case series. Follow-up ranged from 12 to 74 months (mean, 52.3 months). Mean defect size was 5.3 cm(2) (range, 0.96 to 14 cm(2)). All studies reported improvement in clinical outcomes scores. Graft hypertrophy was the most common complication (7.0%). The mean preoperative clinical outcome percentage (based on percentage of outcome scale used) was 37% (standard deviation [SD], 18.9%) and the mean postoperative clinical outcome percentage was 72.7% (SD, 16.9%). The overall percentage increase in clinical outcome scores was 35.7% (SD, 14.2%). Mean CMS was 47.8 (SD, 8.3).

CONCLUSIONS

Cartilage repair in adolescent knees using ACI provides success across different clinical outcomes measures. The only patient- or lesion-specific factor that influenced clinical outcome was the shorter duration of preoperative symptoms.

LEVEL OF EVIDENCE

Level IV, systemic review of Level I-IV studies.

Articular cartilage generation applying PEG-LA-DM/PEGDM copolymer hydrogels

Background

Injuries to the human native cartilage tissue are particularly problematic because cartilage has little to no ability to heal or regenerate itself. Employing a tissue engineering strategy that combines suitable cell sources and biomimetic hydrogels could be a promising alternative to achieve cartilage regeneration. However, the weak mechanical properties may be the major drawback to use fully degradable hydrogels. Besides, most of the fully degradable hydrogels degrade too fast to permit enough extracellular matrix (ECM) production for neocartilage formation. In this study, we demonstrated the feasibility of neocartilage regeneration using swine articular chondrocytes photoencapsualted into poly (ethylene glycol) dimethacrylate (PEGDM) copolymer hydrogels composed of different degradation profiles: degradable (PEG-LA-DM) and nondegradable (PEGDM) macromers in molar ratios of 50/50, 60/40, 70/30, 80/20, and 90/10.

Methods

Articular chondrocytes were isolated enzymatically from juvenile Yorkshire swine cartilage. 6 × 10⁷ cells cells were added to each milliliter of macromer/photoinitiator (I2959) solution. Nonpolymerized gel containing the cells (100 μL) was placed in cylindrical molds (4.5 mm diameter × 6.5 mm in height). The macromer/photoinitiator/chondrocyte solutions were polymerized using ultraviolet (365 nm) light at 10 mW/cm² for 10 mins. Also, an articular cartilaginous ring model was used to examine the capacity of the engineered cartilage to integrate with native cartilage. Samples in the pilot study were collected at 6 weeks. Samples in the long-term experimental groups (60/40 and 70/30) were implanted into nude mice subcutaneously and harvested at 6, 12 and 18 weeks. Additionally, cylindrical constructs that were not implanted used as time zero controls. All of the harvested specimens were examined grossly and analyzed histologically and biochemically.

Results

Histologically, the neocartilage formed in the photochemically crosslinked gels resembled native articular cartilage with chondrocytes in lacunae and surrounded by new ECM. Increases in total DNA, glycosaminoglycan, and hydroxyproline were observed over the time periods studied. The neocartilage integrated with existing native cartilage.

Conclusions

Articular cartilage generation was achieved using swine articular chondrocytes photoencapsulated in copolymer PEGDM hydrogels, and the neocartilage tissue had the ability to integrate with existing adjacent native cartilage.

Patients Scheduled for Chondrocyte Implantation Treatment with MACI Have Larger Defects than Those Enrolled in Clinical Trials

OBJECTIVE

To compare characteristics for patients scheduled for autologous chondrocyte implantation with matrix-assisted chondrocyte implantation (MACI) with those enrolled in clinical trials and to describe differences in patient selection between countries.

DESIGN

Anonymized data from patients scheduled for MACI treatment in the knee in Europe and Australia/Asia were obtained from the Genzyme/Sanofi database. Average age, defect size, and male-female ratio were analyzed and compared by country. Clinical cohort studies and prospective comparative trials using autologous chondrocyte implantation and related treatments were identified and weighted average age, weighted defect size, and male-female ratio were analyzed and compared with data from the database.

RESULTS

From the database 2,690 patients were included with mean age 33.7 years and male-female ratio of 67:33. Mean defect size was 5.64 cm(2) and 70% of the defects were 3 to 10 cm(2). There were significant differences between patients' mean defect sizes between countries. Sixty-nine studies (57 cohorts and 12 prospective comparative trials) with a total of 5,449 patients were identified. The combined weighted mean age was 34.2 years, and the combined weighted mean defect size was 4.89 cm(2). Patients scheduled for MACI had significantly larger defects that those included in clinical trials. There was no significant difference in age. No differences were found between cohorts and prospective comparative trials.

CONCLUSION

The vast majority of patients scheduled for autologous chondrocyte implantation with MACI have chondral defect comparable to that generally recommended, but differences exist between countries. Patients enrolled in clinical trials have significantly smaller defects than those undergoing treatment outside controlled trials.