Characterized chondrocyte implantation in the patellofemoral joint: an up to 4-year follow-up of a prospective cohort of 38 patients

Management of patellar and trochlear cartilage lesions with matrix-induced autologous chondrocyte implantation in conjunction with patellofemoral realignment procedures improves patient-reported outcomes and magnetic resonance image appearance

OBJECTIVES

The aim of this study is to evaluate the relationship between the achievement of clinically significant improvement in patient-reported outcome measures (PROMs) and the postoperative magnetic resonance image (MRI) appearance of matrix-associated chondrocyte implantation (MACI), in conjunction with patellofemoral realignment procedures, for the treatment of grade-IV chondral defects about the patellofemoral joint.

METHODS

A retrospective review of patients undergoing MACI for grade-IV chondral defects of the patella or trochlea by a single sports-medicine-fellowship-trained surgeon from 2017 to 2020 was performed. Concomitant realignment procedures, including tibial tubercle osteotomy and medial patellofemoral ligament reconstruction, were also performed as needed. Patients with preoperative and minimum 1-year postoperative PROMs and postoperative knee MRI were included. MRI scans were obtained at 6.3 (interquartile range: 5.8, 7.5) months postoperatively. A fellowship-trained musculoskeletal radiologist assigned a Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score (range: 0-100, with 100 equating to complete graft healing) to each MRI. Achievement of the minimal clinically important difference (MCID) for International Knee Documentation Committee (IKDC), Knee Injury and Osteoarthritis Score-Quality of Life, and Kujala scores were determined for each patient. Paired t-tests or Wilcoxon rank-sum tests were used to evaluate for an association between achievement of the MCID for each PROM and MOCART score. The average follow-up time and time from surgery to PROMs were 2.7 ​± ​1.5 years and 1.7 ​± ​0.66 years, respectively.

RESULTS

Thirty patients were included. There was a significant improvement in all PROMs from preoperative to postoperative (p ​< ​0.001). More than two-thirds of patients achieved the MCID for each PROM. Patients who achieved the MCID for IKDC had significantly higher MOCART scores (66.5 ​± ​16.2) than those who did not meet the MCID for IKDC (50.6 ​± ​23.6, p ​= ​0.043).

CONCLUSION

MACI for the treatment of patellofemoral chondral injuries is associated with clinically significant improvement in PROMs at short-term follow-up. Clinically significant improvements in IKDC scores are associated with a more mature MRI appearance of the autologous chondrocyte implantation graft on postoperative MRI, as indicated by higher MOCART scores.

LEVEL OF EVIDENCE

IV-Case Series.

Clinical and Radiological Outcomes at ≥10-Year Follow-up After Matrix-induced Autologous Chondrocyte Implantation in the Patellofemoral Joint

BACKGROUND

Matrix-induced autologous chondrocyte implantation (MACI) has demonstrated encouraging outcomes in the treatment of knee cartilage defects, although limited research is available on its longer term (≥10 years) sustainability in the patellofemoral joint.

PURPOSE

To report the clinical and radiological outcomes at ≥10 years in a prospectively recruited cohort of patients undergoing MACI in the patellofemoral joint and compare outcomes in patients undergoing MACI on the patella versus the trochlea.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

The current study prospectively enrolled 95 patients who underwent patellofemoral MACI, of whom 29 (13 patella, 16 trochlea) underwent concomitant tibial tubercle osteotomy. Patients were assessed preoperatively and at 2, 5, and ≥10 years using a range of patient-reported outcome measures (PROMs) including the Knee injury and Osteoarthritis Outcome Score, the 36-item Short Form Health Survey, and the frequency and severity of knee pain as well as patient satisfaction, full active knee flexion and extension, and peak isokinetic knee extensor and flexor torques. High-resolution magnetic resonance imaging (MRI) was performed to assess pertinent graft parameters, as well as determine an overall MRI composite score, per the Magnetic Resonance Observation of Cartilage Repair Tissue scoring system. Results were analyzed according to the graft location (patella or trochlea).

RESULTS

Of the 95 patients recruited, 82 patients (41 patella, 41 trochlea) were available for a clinical review at ≥10 years after surgery (mean follow-up, 11.9 years [range, 10-15 years]). For the whole patellofemoral MACI cohort, all PROMs significantly improved over time (P < .05), with no significant changes (P > .05) observed in any MRI-based score from 2 to ≥10 years after surgery. At ≥10 years, 90.2% (n = 74) were satisfied with MACI in relieving their knee pain, and 85.4% (n = 70) were satisfied with the improvement in their ability to participate in sports. No differences (P > .05) were observed in PROMs between those undergoing patellar MACI and those undergoing trochlear MACI, although a significant group effect was observed for limb symmetry indices of knee extensor (P = .009) and flexor (P = .041) strength, which were greater in those undergoing patellar (vs trochlear) MACI. No statistically significant differences (P > .05) were observed between patellar and trochlear grafts on any MRI-based measure. In the cohort assessed at ≥10 years after surgery, 4 patients (2 patella, 2 trochlea) demonstrated graft failure on MRI scans, although a further 3 patients (all trochlea) were omitted from the ≥10-year review for having already progressed to total knee arthroplasty.

CONCLUSION

Good clinical scores, high levels of patient satisfaction, and adequate graft survivorship were observed at ≥10 years after MACI on the patella and trochlea.

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.

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.

A high-resolution route map reveals distinct stages of chondrocyte dedifferentiation for cartilage regeneration

Articular cartilage damage is a universal health problem. Despite recent progress, chondrocyte dedifferentiation has severely compromised the clinical outcomes of cell-based cartilage regeneration. Loss-of-function changes are frequently observed in chondrocyte expansion and other pathological conditions, but the characteristics and intermediate molecular mechanisms remain unclear. In this study, we demonstrate a time-lapse atlas of chondrocyte dedifferentiation to provide molecular details and informative biomarkers associated with clinical chondrocyte evaluation. We performed various assays, such as single-cell RNA sequencing (scRNA-seq), live-cell metabolic assays, and assays for transposase-accessible chromatin with high-throughput sequencing (ATAC-seq), to develop a biphasic dedifferentiation model consisting of early and late dedifferentiation stages. Early-stage chondrocytes exhibited a glycolytic phenotype with increased expression of genes involved in metabolism and antioxidation, whereas late-stage chondrocytes exhibited ultrastructural changes involving mitochondrial damage and stress-associated chromatin remodeling. Using the chemical inhibitor BTB06584, we revealed that early and late dedifferentiated chondrocytes possessed distinct recovery potentials from functional phenotype loss. Notably, this two-stage transition was also validated in human chondrocytes. An image-based approach was established for clinical use to efficiently predict chondrocyte plasticity using stage-specific biomarkers. Overall, this study lays a foundation to improve the quality of chondrocytes in clinical use and provides deep insights into chondrocyte dedifferentiation.

Cartilage Restoration of Patellofemoral Lesions: A Systematic Review

PURPOSE

This study aimed to systematically analyze the postoperative clinical, functional, and imaging outcomes, complications, reoperations, and failures following patellofemoral cartilage restoration surgery.

METHODS

This review was conducted according to the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). PubMed, EMBASE, and Cochrane Library databases were searched up to August 31, 2018, to identify clinical studies that assessed surgical outcomes of patellofemoral cartilage restoration surgery. The Methodological Index for Non-Randomized Studies (MINORS) was used to assess study quality.

RESULTS

Forty-two studies were included comprising 1,311 knees (mean age of 33.7 years and 56% males) and 1,309 patellofemoral defects (891 patella, 254 trochlear, 95 bipolar, and 69 multiple defects, including the patella or trochlea) at a mean follow-up of 59.2 months. Restoration techniques included autologous chondrocyte implantation (56%), particulated juvenile allograft cartilage (12%), autologous matrix-induced chondrogenesis (9%), osteochondral autologous transplantation (9%), and osteochondral allograft transplantation (7%). Significant improvement in at least one score was present in almost all studies and these surpassed the minimal clinically important difference threshold. There was a weighted 19%, 35%, and 6% rate of reported complications, reoperations, and failures, respectively. Concomitant patellofemoral surgery (51% of patients) mostly did not lead to statistically different postoperative outcomes.

CONCLUSION

Numerous patellofemoral restoration techniques result in significant functional improvement with a low rate of failure. No definitive conclusions could be made to determine the best surgical technique since comparative studies on this topic are rare, and treatment choice should be made according to specific patient and defect characteristics.

LEVEL OF EVIDENCE

Level IV, systematic review of level II to IV studies.

Accurate Reporting of Concomitant Procedures Is Highly Variable in Studies Investigating Knee Cartilage Restoration

OBJECTIVE

Successful clinical outcomes following cartilage restoration procedures are highly dependent on addressing concomitant pathology. The purpose of this study was to document methods for evaluating concomitant procedures of the knee when performed with articular cartilage restoration techniques, and to review their reported findings in high-impact clinical orthopedic studies. We hypothesized that there are substantial inconsistencies in reporting clinical outcomes associated with concomitant procedures relative to outcomes related to isolated cartilage repair.

DESIGN

A total of 133 clinical studies on articular cartilage repair of the knee were identified from 6 high-impact orthopedic journals between 2011 and 2017. Studies were included if they were primary research articles reporting clinical outcomes data following surgical treatment of articular cartilage lesions with a minimum sample size of 5 patients. Studies were excluded if they were review articles, meta-analyses, and articles reporting only nonclinical outcomes (e.g., imaging, histology). A full-text review was then used to evaluate details regarding study methodology and reporting on the following variables: primary cartilage repair procedure, and the utilization of concomitant procedures to address additional patient comorbidities, including malalignment, meniscus pathology, and ligamentous instability. Each study was additionally reviewed to document variation in clinical outcomes reporting in patients that had these comorbidities addressed at the time of surgery.

RESULTS

All studies reported on the type of primary cartilage repair procedure, with autologous chondrocyte implantation (ACI) noted in 43% of studies, microfracture (MF) reported in 16.5%, osteochondral allograft (OCA) in 15%, and osteochondral autograft transplant (OAT) in 8.2%. Regarding concomitant pathology, anterior cruciate ligament (ACL) reconstruction (24.8%) and meniscus repair (23.3%) were the most commonly addressed patient comorbidities. A total of 56 studies (42.1%) excluded patients with malalignment, meniscus injury, and ligamentous instability. For studies that addressed concomitant pathology, 72.7% reported clinical outcomes separately from the cohort treated with only cartilage repair. A total of 16.5% of studies neither excluded nor addressed concomitant pathologies. There was a significant amount of variation in the patient reported outcome scores used among the studies, with the majority of studies reporting International Knee Documentation Committee (IKDC) and Knee Injury and Osteoarthritis Outcomes Score (KOOS) in 47.2% and 43.6% of articles, respectively.

CONCLUSIONS

In this study on knee cartilage restoration, recognition and management of concomitant pathology is inadequately reported in approximately 28% of studies. Only 30% of articles reported adequate treatment of concomitant ailments while scoring their outcomes using one of a potential 18 different scoring systems. These findings highlight the need for more standardized methods to be applied in future research with regard to inclusion, exclusion, and scoring concomitant pathologies with regard to treatment of cartilage defects in the knee.

Arthroscopic Treatment of Patellar and Trochlear Cartilage Lesions with Matrix Encapsulated Chondrocyte Implantation versus Microfracture: Quantitative Assessment with MRI T2-Mapping and MOCART at 4-Year Follow-up

METHODS

Seventeen patients aged 18 to 55 years with symptomatic full-thickness cartilage lesions on either patella or trochlea were treated with matrix autologous chondrocyte implantation (MACI) or microfracture (MF). Both procedures combined with unloading/realigning techniques. Clinical assessment and T2-mapping were evaluated at 48-months.

RESULTS

Clinically results from pre-op to 48-months improved significantly in MACI and MF for Lysholm (p = 0.001, p = 0.001), IKDC-S (p = 0.001, p = 0.002), KOOS-P (p = 0.000, p = 0.002), KOOS-DLA (p = 0.002, p = 0.003), KOOS-Sports/Rec (p = 0.000, p = 0.004), KOOS-QoL (p = 0.000, p = 0.003), KOOS-symptoms (p = 0.001, p = 0.020), and Kujala (p = 0.000, p = 0.01), respectively. Tegner was significant between baseline and 48 months only for MACI (p < 0.008) compared with MF (p = 0.25). No significant difference was observed between groups for any score at 3, 12, 24, and 48-months (p > 0.05). T2-mapping values improved significantly over time in MACI compared with MF at 24 months (39.35 vs. 50.44, p = 0.007) and 48 months (36.54 vs. 48.37, p = 0.005). When comparing control values to MACI at 12-m (p = 0.714), 24-m (p = 0.175), and 48-m (p = 0.097), no significant difference was found. MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) score comparison gave no statistical difference between groups.

CONCLUSIONS

Clinically both techniques improved significantly over time. However, quantitative assessment showed that only newly formed tissue with MACI technique improves significantly since 12-months and maintains stable values compared with native cartilage until 48-month follow-up. MF results were never comparable to those native values. Level of evidence II.

Nasal Chondrocyte-Based Engineered Grafts for the Repair of Articular Cartilage "Kissing" Lesions: A Pilot Large-Animal Study

BACKGROUND

Bipolar or "kissing" cartilage lesions formed on 2 opposite articular surfaces of the knee joint are commonly listed as exclusion criteria for advanced cartilage therapies.

PURPOSE

To test, in a pilot large-animal study, whether autologous nasal chondrocyte (NC)-based tissue engineering, recently introduced for the treatment of focal cartilage injuries, could provide a solution for challenging kissing lesions.

STUDY DESIGN

Controlled laboratory study.

METHODS

Osteochondral kissing lesions were freshly introduced into the knee joints of 26 sheep and covered with NC-based grafts with a low or high hyaline-like extracellular matrix; a control group was treated with a cell-free scaffold collagen membrane (SCA). The cartilage repair site was assessed at 6 weeks and 6 months after implantation by histology, immunohistochemistry, and magnetic resonance imaging evaluation.

RESULTS

NC-based grafts, independently of their composition, induced partial hyaline cartilage repair with stable integrity in surrounding healthy tissue at 6 months after treatment. The SCA repaired cartilage to a similar degree to that of NC-based grafts.

CONCLUSION

Kissing lesion repair, as evidenced in this sheep study, demonstrated the feasibility of the treatment of complex cartilage injuries with advanced biological methods. However, the potential advantages of an NC-based approach over a cell-free approach warrant further investigations in a more relevant preclinical model.

CLINICAL RELEVANCE

NC-based grafts currently undergoing phase II clinical trials have a high potential to replace existing cartilage therapies that show significant limitations in the quality and reproducibility of the repair method. We have brought this innovative concept to the next level by addressing a new clinical indication.

Autologous Chondrocyte Implantation and Mesenchymal Stem Cells for the Treatments of Chondral Defects of the Knee- A Systematic Review

BACKGROUND

There is still a lack of consensus about the best treatment of chondral defects of the knee. We conducted a systematic PRISMA review to evaluate clinical outcomes of Autologous Chondrocyte Implantation (ACI) and Mesenchymal Stem Cell (MSC) injections for the treatment of focal chondral defects of the knee.

METHODS

A systematic review of literature was performed according to the PRISMA guidelines. All the articles reporting data on ACI and MSC treatments for chondral defects of the knee were considered for inclusion. The main databases were accessed: PubMed, Medline, CINAHL, Cochrane, Embase and Google Scholar. The statistical analysis was performed using the Review Manager Software.

RESULTS

In the p-ACI group (987 knees), the Cincinnati Score improved by 18.94% (p=0.1), VAS by 38% (p=0.01), Tegner score by 19.11% (p=0.03), Lysholm score by 22.40% (p=0.01), IKCD by 27.36% (p=0.003). In the c-ACI group (444 knees), the Cincinnati Score improved by 23.80% (p=0.08), KOOS by 23.48% (p=0.03), VAS by 33.2% (p=0.005), IKDC by 33.30% (p=0.005). In the m-ACI group (599 knees), the Cincinnati Score improved by 26.80% (p=0.08), KOOS by 31.59% (p=0.1), VAS by 30.43% (p=0.4), Tegner score by 23.1% (p=0.002), Lysholm score by 31.14% (p=0.004), IKCD by 30.57% (p<0.001). In the MSCs group (291 knees), the KOOS improved by 29.7% (p=0.003), VAS by 41.89% (p<0.001), Tegner score by 25.81% (p=0.003), Lysholm score by 36.96% (p<0.001), IKCD by 30.57% (p=0.001).

CONCLUSION

Both ACI and MSC therapies can be considered as a concrete solution to treat focal chondral defects of the knee.

Optimizing Outcomes in Articulating (Kissing) Patellofemoral Joint Osteochondral Lesions: Case Report and Review of the Literature

A 32-year-old woman with bipolar patellofemoral chondral lesions caused by traumatic patella dislocation underwent autologous chondrocyte implantation with concomitant tibial tubercle osteotomy and MPFL reconstruction. At 1- and 2-year follow-ups, the patient had returned to all previous activities with considerable improvement in all patient-reported outcome scores. This is an encouraging treatment option for a historically difficult therapeutic problem.

Effect of the defect localization and size on the success of third-generation autologous chondrocyte implantation in the knee joint

INTRODUCTION

Femoral and patellar cartilage defects with a defect size > 2.5 cm² are a potential indication for an autologous chondrocyte implantation (ACI). However, the influence of the localization and the absolute and relative defect size on the clinical outcome has not yet been determined. The purpose of this study is to analyze the influence of the localization and the absolute and relative defect size on the clinical outcome after third-generation autologous chondrocyte implantation.

METHODS

A total of 50 patients with cartilage defects of the knee were treated with third-generation autologous chondrocyte implantation (Novocart® 3D). A match paired analysis was performed of 25 treated femoral and 25 treated patella defects with a follow-up of three years. MRI data was used to do the manual segmentation of the cartilage layer throughout the knee joint. The defect size was determined by taking the defect size measured in the MRI in relation to the whole cartilage area. The clinical outcome was measured by the IKDC score and VAS pre-operatively and after six, 12, 24, and 36 months post-operatively.

RESULTS

IKDC and VAS scores showed a significant improvement from the baseline in both groups. Femoral cartilage defects showed significantly superior clinical results in the analyzed scores compared to patellar defects. The femoral group improved IKDC from 33.9 (SD 18.1) pre-operatively to 71.5 (SD 17.4) after three years and the VAS from 6.9 (SD 2.9) pre-operatively to 2.4 (SD 2.5) after three years. In the patellar group, IKDC improved from 36.1 (SD 12.6) pre-operatively to 54.7 (SD 20.3) after three years and the VAS improved from 6.7 (SD 2.8) pre-operatively to 3.4 (SD 2.) after three years. Regarding the defect size, results showed that the same absolute defect size at med FC (4.8, range 2-15) and patella (4.6, range 2-12) has a significantly different share of the total cartilaginous size of the joint compartment (med FC: 6.7, range 1.2-13.9; pat: 18.9, range 4.0-47.0). However, there was no significant influence of the relative defect size on the clinical outcome in either patellar or femoral localization.

CONCLUSION

Third-generation autologous chondrocyte implantation in ACI-treated femoral cartilage defects leads to a superior clinical outcome in a follow-up of three years compared with patellar defects. No significant influence of the defect size was found in either femoral or patellar cartilage defects.

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.

An Expert Consensus Statement on the Management of Large Chondral and Osteochondral Defects in the Patellofemoral Joint

Background

Cartilage lesions of the patellofemoral joint constitute a frequent abnormality. Patellofemoral conditions are challenging to treat because of complex biomechanics and morphology.

Purpose

To develop a consensus statement on the functional anatomy, indications, donor graft considerations, surgical treatment, and rehabilitation for the management of large chondral and osteochondral defects in the patellofemoral joint using a modified Delphi technique.

Study Design

Consensus statement.

Methods

A working group of 4 persons generated a list of statements related to the functional anatomy, indications, donor graft considerations, surgical treatment, and rehabilitation for the management of large chondral and osteochondral defects in the patellofemoral joint to form the basis of an initial survey for rating by a group of experts. The Metrics of Osteochondral Allografts (MOCA) expert group (composed of 28 high-volume cartilage experts) was surveyed on 3 occasions to establish a consensus on the statements. In addition to assessing agreement for each included statement, experts were invited to propose additional statements for inclusion or to suggest modifications of existing statements with each round. Predefined criteria were used to refine statement lists after each survey round. Statements reaching a consensus in round 3 were included within the final consensus document.

Results

A total of 28 experts (100% response rate) completed 3 rounds of surveys. After 3 rounds, 36 statements achieved a consensus, with over 75% agreement and less than 20% disagreement. A consensus was reached in 100.00% of the statements relating to functional anatomy of the patellofemoral joint, 88.24% relating to surgical indications, 100.00% relating to surgical technical aspects, and 100.00% relating to rehabilitation, with an overall consensus of 95.5%.

Conclusion

This study established a strong expert consensus document relating to the functional anatomy, surgical indications, donor graft considerations for osteochondral allografts, surgical technical aspects, and rehabilitation concepts for the management of large chondral and osteochondral defects in the patellofemoral joint. Further research is required to clinically validate the established consensus statements and better understand the precise indications for surgery as well as which techniques and graft processing/preparation methods should be used based on patient- and lesion-specific factors.

Therapeutic "Tool" in Reconstruction and Regeneration of Tissue Engineering for Osteochondral Repair

Repairing osteochondral defects to restore joint function is a major challenge in regenerative medicine. However, with recent advances in tissue engineering, the development of potential treatments is promising. In recent years, in addition to single-layer scaffolds, double-layer or multilayer scaffolds have been prepared to mimic the structure of articular cartilage and subchondral bone for osteochondral repair. Although there are a range of different cells such as umbilical cord stem cells, bone marrow mesenchyml stem cell, and others that can be used, the availability, ease of preparation, and the osteogenic and chondrogenic capacity of these cells are important factors that will influence its selection for tissue engineering. Furthermore, appropriate cell proliferation and differentiation of these cells is also key for the optimal repair of osteochondral defects. The development of bioreactors has enhanced methods to stimulate the proliferation and differentiation of cells. In this review, we summarize the recent advances in tissue engineering, including the development of layered scaffolds, cells, and bioreactors that have changed the approach towards the development of novel treatments for osteochondral repair.

Anatomic Risk Factors for Focal Cartilage Lesions in the Patella and Trochlea: A Case-Control Study

BACKGROUND

Focal cartilage lesions in the patellofemoral (PF) joint are common. Several studies correlated PF risk factors with PF instability, anterior knee pain, and PF arthritis; however, there is a lack of evidence correlating those factors to PF focal cartilage lesions.

PURPOSE

To evaluate the influence of the anatomic PF risk factors in patients with isolated focal PF cartilage lesions.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Patients with isolated PF focal cartilage lesions were included in the cartilage lesion group, and patients with other pathologies and normal PF cartilage were included in the control group. Multiple PF risk factors were accessed on magnetic resonance imaging scans: patellar morphology (patellar width, patellar thickness, and patellar angle), trochlear morphology (trochlear sulcus angle, lateral condyle index, and trochlear sulcus depth), patellar height (Insall-Salvati ratio and Caton-Deschamps index), axial patellar positioning (patellar tilt, angle of Fulkerson), and quadriceps vector (tibial tuberosity-trochlear groove distance).

RESULTS

A total of 135 patients were included in the cartilage lesion group and 100 in the control group. As compared with the control group, the cartilage lesion group had a higher sulcus angle (P = .0007), lower trochlear sulcus depth (P < .0001), lower angle of Fulkerson (P < .0001), lower patellar width (P = .0003), and higher Insall-Salvati ratio (P < .0001). From the patients in the cartilage lesion group, 36% had trochlear dysplasia; 27.6%, patella alta; and 24.7%, abnormal patellar tilt. These parameters were more frequent in the cartilage lesion group (P < .0001). Trochlear lesions were more frequent in men, presented at an older age, and had fewer associated anatomic risk factors. Patellar lesions, conversely, were more frequent in women, presented at younger age, and were more closely associated with anatomic risk factors.

CONCLUSION

PF anatomic abnormalities are significantly more common in patients with full-thickness PF cartilage lesions. Trochlear dysplasia, patella alta, and excessive lateral patellar tilt are the most common correlated factors, especially in patellar lesions.

Autologous Chondrocyte Implantation for Bipolar Chondral Lesions in the Patellofemoral Compartment: Clinical Outcomes at a Mean 9 Years' Follow-up

BACKGROUND

Treating bipolar chondral lesions in the patellofemoral (PF) compartment is a challenging problem. There are few reports available on the treatment of bipolar chondral lesions in the PF compartment.

PURPOSE

To evaluate the clinical outcomes and graft survivorship after autologous chondrocyte implantation (ACI) for the treatment of bipolar chondral lesions in the PF compartment.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

The authors evaluated 58 patients who had ACI by a single surgeon for the treatment of symptomatic bipolar chondral lesions in the PF compartment between November 1995 and June 2014. All 58 patients (60 knees; mean age, 36.6 years) were included with a minimum 2-year follow-up. The mean ± SD sizes of the patellar and trochlear lesions were 5.6 ± 2.7 cm² and 4.2 ± 2.8 cm², respectively. Forty-two patients had osteotomy, as they had PF lateral maltracking, patellar instability, or tibiofemoral malalignment. Patients were evaluated with the modified Cincinnati Knee Rating Scale, Western Ontario and McMaster Universities Osteoarthritis Index, visual analog scale, the 36-Item Short Form Health Survey, and a patient satisfaction survey. Radiographs were evaluated with the Iwano classification.

RESULTS

Overall, the survival rates were 83% and 79% at 5 and 10 years, respectively. Of the 49 (82%) knees with retained grafts, all functional scores significantly improved postoperatively with a very high satisfaction rate (88%) at a mean 8.8 ± 4.2 years after ACI (range, 2-16 years). At the most recent follow-up, 28 of 49 successful knees were radiographically assessed (mean, 4.9 years; range, 2-17 years), with no increase of the Iwano classification in 26 knees. Outcomes for 11 patients were considered failures at a mean 2.9 years. Forty-two knees (70%) required a mean 1.0 subsequent surgical procedure. The primary reasons for chondroplasty were hypertrophy of the ACI graft (17; periosteum in 14, collagen membrane in 3), delamination of the ACI graft (5; periosteum in 4, collagen membrane in 1), and new chondral lesions (3). The best survival rates were observed among patients who underwent ACI with concomitant tibial tubercle osteotomy (TTO) as the first procedure without previous failed TTO and/or marrow stimulation technique (91% at 5 and 10 years), while the worst survival rates were observed among patients who had previous marrow stimulation (43% at 5 and 10 years).

CONCLUSION

Results demonstrated that ACI with concomitant osteotomy, when it is necessary for the treatment of bipolar/kissing lesions in the PF compartments, gives significant improvement in pain and function, with good survival rates at 5 and 10 years (83% and 79%, respectively). The high patient satisfaction rate is encouraging, and a high survival rate can be expected when ACI with a concomitant TTO is performed at the initial surgery for this difficult condition.

Patellar chondral defect treatment with a cell-free polyglycolic acid-hyaluronan-based implant and platelet-rich fibrin glue after previously failed microfracture

Cartilage defects of the patella are difficult to treat due to the complex anatomy of the patellofemoral joint. First-line treatment of chondral patellar defects often results in failure independent of the surgical technique. Moreover, there is no recommendation for second-line treatment of failed patellar defect treatment. Here, the case of a 48-year-old active patient with complex patellofemoral problems who had undergone multiple previous surgeries, including failed microfracture of a full-thickness cartilage defect on his patella, is presented. The patient was treated with a polymer-based implant in combination with microfracture and autologous platelet-rich fibrin glue. Post-surgical follow-up after 6 months with magnetic resonance imaging revealed complete defect filling, which was confirmed by second-look arthroscopy after 9 months, showing the formation of cartilage repair tissue. This procedure seems to be a viable and safe treatment option for patients suffering from full-thickness chondral lesions on the patella that have previously failed microfracture at the same location.

Patellofemoral Cartilage Repair

Purpose of Review

This review provides an overview of well-established and newly developed cartilage repair techniques for cartilage defects in the patellofemoral joint (PFJ). An algorithm will be presented for approaching cartilage defects considering the distinct anatomy of both the patellar and trochlear articular surfaces.

Recent Findings

Recent studies on cartilage repair in the PFJ have demonstrated improved outcomes in an attempt to delay or obviate the need for arthroplasty, and improve symptoms in young patients. While autologous chondrocyte implantation shows good and excellent outcomes for chondral lesions, osteochondral defects are adequately addressed with osteochondral allograft transplantation. In case of patellar malalignment, concomitant tibial tubercle osteotomy can significantly improve outcomes. Particulated cartilage and bone marrow aspirate concentrate are potential new alternative treatments for cartilage repair, currently in early clinical studies.

Summary

Due to the frequency of concomitant anatomic abnormalities in the PFJ, a thorough clinical examination combined with careful indication for each procedure in each individual patient combined with meticulous surgical technique is central to achieve satisfying outcomes. Additional comparative studies of cartilage repair procedures, as well as investigation of newer techniques, are needed.

Treatment of Failed Articular Cartilage Reconstructive Procedures of the Knee: A Systematic Review

Background

Symptomatic articular cartilage lesions of the knee are common and are being treated surgically with increasing frequency. While many studies have reported outcomes following a variety of cartilage restoration procedures, few have investigated outcomes of revision surgery after a failed attempt at cartilage repair or reconstruction.

Purpose

To investigate outcomes of revision cartilage restoration procedures for symptomatic articular cartilage lesions of the knee following a previously failed cartilage reconstructive procedure.

Study Design

Systematic review; Level of evidence, 4.

Methods

A literature search was performed by use of the PubMed, EMBASE, and MEDLINE/Ovid databases for relevant articles published between 1975 and 2017 that evaluated patients undergoing revision cartilage restoration procedure(s) and reported outcomes using validated outcome measures. For studies meeting inclusion criteria, relevant information was extracted.

Results

Ten studies met the inclusion criteria. Lesions most commonly occurred in the medial femoral condyle (MFC) (52.8%), with marrow stimulation techniques (MST) the index procedure most frequently performed (70.7%). Three studies demonstrated inferior outcomes of autologous chondrocyte implantation (ACI) following a previous failed cartilage procedure compared with primary ACI. One study comparing osteochondral allograft (OCA) transplant following failed microfracture (MFX) with primary OCA transplant demonstrated similar clinical outcomes and graft survival at midterm follow-up. No studies reported outcomes following osteochondral autograft transfer (OAT) or newer techniques.

Conclusion

This systematic review of the literature reporting outcomes following revision articular cartilage restoration procedures (most commonly involving the MFC) demonstrated a high proportion of patients who underwent prior MST. Evidence is sufficient to suggest that caution should be taken in performing ACI in the setting of prior MST, likely secondary to subchondral bone compromise. OCA appears to be a good revision treatment option even if the subchondral bone has been violated from prior surgery or fracture.

Considerations in Evaluating Treatment Options for Patellofemoral Cartilage Pathology

Patellofemoral (PF) pain, a subset of anterior knee pain, presents a particularly challenging diagnosis due to the multifactorial etiology. Within this group, assigning the patient's symptoms to a patellofemoral cartilage lesion is indirect; that is, a diagnosis by exclusion as hyaline cartilage is aneural. In addition, these PF compartment lesions are often in conjunction with various comorbidities, for example, malalignment and/or instability. In light of these factors and the high shear and compression stresses at the PF compartment, patellar and trochlear chondral lesions require unique treatment considerations from the tibiofemoral compartments. A thorough understanding of the various cartilage restoration techniques available is necessary to select the best option for the individual patient/knee/lesion noting that there is overlap of techniques' applications. In addition, failure to address and correct associated comorbidities may jeopardize the outcome of any cartilage restoration procedure. That is, the key to achieving optimal outcomes with PF cartilage restoration is to select the best cartilage treatment for the particular setting and to concomitantly optimize the PF biomechanical environment and stability.

Abnormal Patella Height Based on Insall-Salvati Ratio and its Correlation with Patellar Cartilage Lesions: An Extremity-Dedicated Low-Field Magnetic Resonance Imaging Analysis of 1703 Chinese Cases

Background and aims:

Diagnostic performance of patellar position for patellar cartilage lesions remains unclear. The aim of this study was to assess the abnormal patella height and its correlation with chondral lesions of the patellofemoral joint in China.

Material and methods:

A total of 1703 consecutive patients who performed knee joint examination using an extremity-dedicated low-field magnetic resonance imaging were enrolled in this study. Patellar cartilage lesions were diagnosed based on the result of magnetic resonance imaging and clinical data. Patella height was defined as the ratio of patellar tendon length to patellar length according to Insall-Salvati index. Patella alta and infera were defined as tendon length/patellar length >1.2 and <0.8, respectively.

Results:

The total prevalence of patellar cartilage lesions was 38.0%. The prevalence in females was significantly higher than that in males (46.4% vs 28.8%, p < 0.001). Age notably increased the incidence of patellar cartilage lesions ( p < 0.001). Logistic regression analysis showed that tendon length/patellar length ratio was significantly correlated with patellar cartilage lesions (odds ratio = 6.380, p < 0.001). Furthermore, patients with cartilage lesions showed significantly higher rates of patella alta and infera ( p < 0.001). In addition, receiver operating characteristic curve analysis demonstrated that abnormal patella height had statistical significance in diagnosing cartilage lesions ( p < 0.001). However, the area under the curve (0.596; 95% confidence interval: 0.568–0.624) and sensitivity (47.0%) were relatively low, while the specificity was 72.2%.

Conclusions:

Patients with patellar cartilage lesions have an increased tendon length/patellar length ratio. The abnormal patella height is significantly correlated with chondral lesions and can be used as a potential diagnostic marker.

A cadaveric investigation into the demographic and bony alignment properties associated with osteoarthritis of the patellofemoral joint

BACKGROUND

Patellofemoral joint osteoarthritis is common, although circumstances dictating its evolution and pathogenesis remain unclear. Advances in surgical technique have improved the ability to modify long-bone alignment in the coronal, sagittal, and axial planes. However, to our knowledge, there is no significant long-term data available in regard to the relationship between anatomic alignment parameters most amenable to surgical modification and patellofemoral joint osteoarthritis.

METHODS

Five-hundred and seventy-one cadaveric skeletons were obtained from the Hamann-Todd osteological collection. Mechanical lateral distal femoral angle, medial proximal tibial angle, tibial slope, femoral version, tibial torsion, the position of the tibial tubercle relative to the width of the tibial plateau, trochlear depth, and patellar size were measured using validated techniques. A previously published grading system for patellofemoral joint arthritis was used to quantify macroscopic signs of degenerative joint disease.

RESULTS

Increasing age (standardized beta 0.532, p<0.001), female gender (standardized beta 0.201, p=0.002), and decreasing mechanical lateral distal femoral angle (standardized beta -0.128, p=0.025) were independent correlates of increased patellofemoral joint osteoarthritis. A relatively more laterally positioned tibial tubercle trended towards predicting patellofemoral joint osteoarthritis (standardized beta 0.080, p=0.089).

CONCLUSIONS

These findings confirm that patellofemoral joint osteoarthritis is strongly associated with increasing age and female gender. Valgus alignment of the distal femur, a relatively more lateral location of the tibial tubercle, and a shallower trochlear grove appear to have modest effects on the development of patellofemoral joint osteoarthritis.

Early osteoarthritis of the patellofemoral joint

Patellofemoral joint cartilage lesions are associated with a variety of clinical situations including blunt trauma, lateral patella dislocations, or as a secondary development in the setting of abnormal joint loading. There is a need for more clarity on how to best address these lesions. Most specifically, when is it necessary to surgically treat these lesions of the patella and trochlea and which technique to use? This review will focus on the spectrum of patellofemoral disease/injury and their treatment strategies, with special emphasis on cartilage damage and early osteoarthritis. Chapter sections will review the most common scenarios of cartilage damage in the patellofemoral joint, with an attempt to summarize current treatment, their outcomes, remaining challenges and unanswered questions.

Autologous chondrocyte implantation: Is it likely to become a saviour of large-sized and full-thickness cartilage defect in young adult knee?

PURPOSE

A literature review of the first-, second- and third-generation autologous chondrocyte implantation (ACI) technique for the treatment of large-sized (>4 cm(2)) and full-thickness knee cartilage defects in young adults was conducted, examining the current literature on features, clinical scores, complications, magnetic resonance image (MRI) and histological outcomes, rehabilitation and cost-effectiveness.

METHODS

A literature review was carried out in the main medical databases to evaluate the several studies concerning ACI treatment of large-sized and full-thickness knee cartilage defects in young adults.

RESULTS

ACI technique has been shown to relieve symptoms and improve functional assessment in large-sized (>4 cm(2)) and full-thickness knee articular cartilage defect of young adults in short- and medium-term follow-up. Besides, low level of evidence demonstrated its efficiency and durability at long-term follow-up after implantation. Furthermore, MRI and histological evaluations provided the evidence that graft can return back to the previous nearly normal cartilage via ACI techniques. Clinical outcomes tend to be similar in different ACI techniques, but with simplified procedure, low complication rate and better graft quality in the third-generation ACI technique.

CONCLUSION

ACI based on the experience of cell-based therapy, with the high potential to regenerate hyaline-like tissue, represents clinical development in treatment of large-sized and full-thickness knee cartilage defects.

LEVEL OF EVIDENCE

IV.

Osteochondral Allograft Transplantation of the Femoral Trochlea

BACKGROUND

Osteochondral allograft (OCA) transplantation is a recognized treatment modality for cartilage damage in the knee. Few reports are available on outcomes of OCA in the patellofemoral joint, and there are no reports on lesions isolated to the femoral trochlea.

PURPOSE

To evaluate graft survivorship and clinical outcomes in patients who had an OCA to the femoral trochlea.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

An OCA database was used to identify 29 knees in 28 patients (mean age, 30.2 years; range, 12-47 years; 8 female, 20 male) who were treated with a fresh OCA transplant limited to the femoral trochlea. The primary outcome was graft survivorship, and the minimum follow-up was 2 years. Clinical outcomes were assessed by the modified Merle d'Aubigné-Postel (18-point) score; Knee Society function (KS-F) score; International Knee Documentation Committee (IKDC) pain, function, and total scores; and University of California, Los Angeles (UCLA) activity score. The OCA patient satisfaction score (5-point scale from extremely satisfied to dissatisfied) was also reported.

RESULTS

The mean follow-up period was 7.0 years (range, 2.1-19.9 years). Graft survivorship was 100% at 5 years and 91.7% at 10 years. One patient was converted to a total knee arthroplasty 7.6 years after OCA surgery. The mean modified Merle d'Aubigné-Postel score improved from 13.0 to 16.1, the mean KS-F score from 65.6 to 85.2, and the mean IKDC total score from 38.5 to 71.9; the mean UCLA score was 7.9 postoperatively. Eighty-nine percent of patients were extremely satisfied or satisfied with the outcome of surgery.

CONCLUSION

Fresh OCA transplantation resulted in excellent clinical outcomes in this patient cohort with articular cartilage damage to the femoral trochlea. The procedure resulted in improved pain and function and high patient satisfaction.

Repair of retropatellar cartilage defects in the knee with microfracture and a cell-free polymer-based implant

INTRODUCTION

To analyze magnetic resonance imaging (MRI) at 3T and the clinical outcome in a short-term pilot study after treatment of retropatellar cartilage defects with microfracturing and subsequent covering with the cell-free chondrotissue(®) polyglycolic acid-hyaluronan implant.

METHODS

Five consecutive patients after microfracturing and defect coverage with the chondrotissue(®) implant immersed with autologous serum were included. After a mean follow-up of 21 months (range 11-31 months), defect fill and repair tissue quality was assessed by 3-T MRI followed by applying established MRI scoring systems. The patients' situation was assessed using the Knee injury and Osteoarthritis Outcome Score (KOOS) and a patients' satisfaction questionnaire.

RESULTS

Magnetic resonance imaging showed good to excellent defect fill with complete integration. The mean MOCART score was 61 (range 50-75) points. The mean Henderson score was 7 (range 6-9) points. All patients showed subchondral bone alterations. The KOOS showed good values in all sub-categories in 4 out of 5 patients and a mean overall score of 73 (range 40-90) points. Two patients rated the outcome as excellent, two as good and one as fair. All patients would have the procedure again and recommend it.

CONCLUSIONS

In this small case series, the coverage of symptomatic retropatellar cartilage defects with the chondrotissue(®) implant after microfracturing was safe and feasible with improvement of the patients' situation at short-term follow-up.

LEVEL OF EVIDENCE

IV, case series.

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

BACKGROUND

While matrix-induced autologous chondrocyte implantation (MACI) has demonstrated encouraging outcomes in the treatment of knee chondral defects, there remains little available research specifically investigating its use in the patellofemoral joint.

PURPOSE

To prospectively evaluate the clinical and radiologic outcome of MACI in the patellofemoral joint.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

In 47 consecutive patients undergoing patellofemoral MACI, clinical (Knee injury and Osteoarthritis Outcome Score, 36-Item Short Form Health Survey, visual analog scale for pain, 6-minute walk test, knee range of motion, and strength assessment) and magnetic resonance imaging (MRI) assessments were undertaken before and 3, 12, and 24 months after surgery. The MRI was performed to assess graft infill and determine an overall MRI composite score. Results were analyzed according to (1) the patient sample overall and (2) after stratification into 4 subgroups per implant location (patella or trochlea) as well as whether or not adjunct tibial tubercle transfer for patellofemoral malalignment was required.

RESULTS

The overall patient sample, as well as each of the 4 procedural subgroups, demonstrated clinically and statistically significant (P < .05) improvements over time for all clinical scores. Graft infill and the MRI composite score also demonstrated statistically significant (P < .05) improvements over time, with no evidence of a main effect for procedure group or interaction between procedure group and time. At 24 months after surgery, 40.4% (n = 19) of patients exhibited complete graft infill comparable with the adjacent native cartilage, with a further 6.4% (n = 3) demonstrating a hypertrophic graft. A further 31.9% (n = 15) of patients exhibited 50% to 100% tissue infill, and 17% (n = 8) demonstrated <50% tissue infill. Two patients (4.3%) demonstrated graft failure. At 24 months after surgery, 85% (n = 40) of patients were satisfied with the results of their MACI surgery.

CONCLUSION

These results demonstrate that MACI provides improved clinical and radiologic outcomes to 24 months in patients undergoing treatment specifically for articular cartilage defects on the patella or trochlea, with and without concurrent realignment of the extensor mechanism if required.

Treatment of articular cartilage lesions of the knee by microfracture or autologous chondrocyte implantation: a systematic review

PURPOSE

We performed a systematic review of the treatment of articular cartilage lesions of the knee by microfracture or autologous chondrocyte implantation to determine the differences in patient outcomes after these procedures.

METHODS

We searched PubMed/Medline, Embase, and The Cochrane Library databases in the period from January 10 through January 20, 2013, and included 34 articles in our qualitative analysis.

RESULTS

All studies showed improvement in outcome scores in comparison with baseline values, regardless of the treatment modality. The heterogeneity of the results presented in the studies precluded a meta-analysis.

CONCLUSIONS

Microfracture appears to be effective in smaller lesions and is usually associated with a greater proportion of fibrocartilage production, which may have an effect on durability and eventual failure. Autologous chondrocyte implantation is an effective treatment that may result in a greater proportion of hyaline-like tissue at the repair site, which may in turn have a beneficial effect on durability and failure; it appears to be effective in larger lesions. Autologous chondrocyte implantation with periosteum has been shown to be associated with symptomatic cartilage hypertrophy more frequently than autologous chondrocyte implantation with collagen membrane. Matrix-associated autologous chondrocyte implantation is technically less challenging than the other techniques available, and in lesions greater than 4 cm(2), it has been shown to be more effective than microfracture.

LEVEL OF EVIDENCE

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

Cell therapy in joint disorders

Context:

Articular cartilage possesses poor natural healing mechanisms, and a variety of non-cell-based and cell-based treatments aim to promote regeneration of hyaline cartilage.

Data Sources:

A review of the literature to December 2013 using PubMed with search criteria including the keywords stem cell, cell therapy, cell transplantation, cartilage, chondral, and chondrogenic.

Study Selection:

Forty-five articles were identified that employed local mesenchymal stem cell (MSC) therapy for joint disorders in humans. Nine comparative studies were identified, consisting of 3 randomized trials, 5 cohort studies, and 1 case-control study.

Study Type:

Clinical review.

Level of Evidence:

Level 4.

Data Extraction:

Studies were assessed for stem cell source, method of implantation, comparison groups, and concurrent surgical techniques.

Results:

Two studies comparing MSC treatment to autologous chondrocyte implantation found similar efficacy. Three studies reported clinical benefits with intra-articular MSC injection over non-MSC controls for cases undergoing debridement with or without marrow stimulation, although a randomized study found no significant clinical difference at 2-year follow-up but reported better 18-month magnetic resonance imaging and histologic scores in the MSC group. No human studies have compared intra-articular MSC therapy to non-MSC techniques for osteoarthritis in the absence of surgery.

Conclusion:

Mesenchymal stem cell–based therapies appear safe and effective for joint disorders in large animal preclinical models. Evidence for use in humans, particularly, comparison with more established treatments such as autologous chondrocyte implantation and microfracture, is limited.

A 5-year follow-up after cartilage repair in the knee using a platelet-rich plasma-immersed polymer-based implant

The aim of our study was to analyze the clinical outcome after repair of cartilage defects of the knee with subchondral drilling and resorbable polymer-based implants immersed with autologous platelet-rich plasma (PRP). Fifty-two patients with focal chondral defects were treated with subchondral drilling, followed by covering with a polyglycolic acid - hyaluronan (PGA-HA) implant (chondrotissue®) immersed with autologous PRP. At 5-year follow-up, patients' situation was assessed using the Knee Injury and Osteoarthritis Outcome Score (KOOS) and compared to the pre-operative situation. The KOOS showed clinically meaningful and significant (p < 0.05) improvement in all subcategories compared to baseline. Subgroup analysis showed that there were no differences in the clinical outcome regarding defect size and localization as well as degenerative condition of the knee. Cartilage repair was complete in 20 out of 21 patients at 4-year follow-up as shown by magnetic resonance observation of cartilage repair tissue (MOCART) scoring. Covering of focal cartilage defects with the PGA-HA implant and PRP after bone marrow stimulation leads to a lasting improvement of the patients' situation.

Matrix-induced autologous chondrocyte implantation (MACI) for chondral defects in the patellofemoral joint

PURPOSE

Both autologous chondrocyte implantation (ACI) and tibial tubercle transfer (TTT) have been used to treat chondral defects in the patellofemoral joint resulting in clinical improvement. Our study investigates the magnetic resonance imaging (MRI) appearance of the matrix-induced autologous chondrocyte implantation (MACI) graft at 5-year follow-up to determine if it provides a durable treatment option in patients with an average age of 42 (standard deviation 11.6).

METHODS

Twenty-three patients were available for follow-up. Nine patients required realignment of the extensor mechanism with lateral release and TTT. The MRI magnetic resonance observation of cartilage repair tissue (MOCART) scoring system was used to assess the graft status. Clinical outcomes were assessed at these time periods.

RESULTS

The mean weighted MOCART composite score improved from 2.87 at 3 months to 3.39 at 5 years, indicating an intact appearance in most grafts. Graft height measured >50% of the adjacent native cartilage in 82% of patients. Clinical improvement assessed by the Knee Injury and Osteoarthritis Outcome Score, SF-36 (PCS) and the 6-minute walk test was demonstrated between pre-operative scores and final 5-year follow-up. 91% of patients would undergo MACI again. Correlation between MOCART and clinical scores were low in MACI to the patellofemoral joint. No significant difference was found in outcome between those that required realignment surgery compared with those that did not.

CONCLUSION

Patellofemoral MACI provides a durable graft on MRI assessment at 5 years with resultant clinical improvement. Further work is needed to determine which defect locations may benefit most from this procedure.

LEVEL OF EVIDENCE

IV.

Management of patellofemoral chondral injuries

Treatment of patellofemoral chondral defects is fraught with difficulty because of the generally inferior outcomes and significant biomechanical complexity of the joint. Noyes and Barber-Westin38 performed a systematic review of large (>4 cm2) patellofemoral ACI (11 studies), PFA (5 studies), and osteochondral allografting (2 studies) in patients younger than 50 years. Respectively, failures or poor outcomes were noted in 8% to 60% after ACI, 22% after PFA, and 53% after osteochondral allograft treatment. As noted in the outcome reviews earlier, unacceptable complication and reoperation rates were reported from all 3 procedures, and it was concluded that each operation had unpredictable results for this patient demographic. This study highlights the importance of strict indications and working to address all concomitant diseases to decrease revision rate. Outcomes are most predictable in young patients with low BMI and unipolar defects lower than 4 cm2.

Treatment of "patellofemoral" cartilage lesions with matrix-assisted autologous chondrocyte transplantation: a comparison of patellar and trochlear lesions

BACKGROUND

Matrix-assisted autologous chondrocyte transplantation (MACT) has been shown to offer good outcomes at midterm follow-up, but results are heterogeneous among different patients and lesion types. Being part of the same joint, both patellar and trochlear cartilage lesions are commonly considered to be affected by the same treatment issues, and therefore, it is common practice to report results obtained treating these lesions together.

PURPOSE

To determine, in a large cohort of patients prospectively followed at midterm follow-up for patellofemoral chondral defects, if patellar and trochlear defects actually represent different clinical conditions with different healing potentials after cartilage treatment.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A total of 49 consecutive patients with full-thickness patellofemoral chondral lesions of the knee were treated with MACT at the authors' institute and followed prospectively for a minimum follow-up of 5 years. Among these 49 patients, 28 were affected by patellar lesions, 17 were affected by trochlear lesions, and 4 had both patellar and trochlear defects. The clinical outcome was analyzed with International Knee Documentation Committee (IKDC) subjective, EuroQol visual analogue scale (EQ-VAS), Kujala, and Tegner scores.

RESULTS

A statistically significant improvement in all scores was observed after treatment. Patellar lesions required more realignment procedures and were more common in women. The comparative analysis showed better results for trochlear lesions compared with patellar lesions at all follow-ups, with mean IKDC scores at 5-year follow-up of 89.6 ± 12.7 and 69.7 ± 17.6, respectively (P < .0005). Better results were also shown for the mean Kujala score (92.4 ± 14.7 vs 81.5 ± 12.7, respectively; P = .012) and mean EQ-VAS score (90.0 ± 10.8 vs 81.9 ± 11.7, respectively; P = .027). Finally, the sport activity level evaluated with the Tegner score confirmed the same trend; even though neither patellar nor trochlear lesion groups reached the preinjury level, both improved after treatment, with a significantly higher improvement in the trochlear lesion group (5.9 ± 1.8 vs 3.9 ± 1.7, respectively; P < .0005).

CONCLUSION

Patient characteristics differ between patellar and trochlear cartilage defects, and moreover, the results obtained are significantly different, with a markedly good outcome in cases with trochlear lesions and less satisfactory results for patients affected by cartilage lesions of the patella. Thus, patellar and trochlear defects should be considered separately when evaluating the outcome of cartilage treatments in this anatomic region.

Advanced patellofemoral cartilage lesions in patients younger than 50 years of age: is there an ideal operative option?

PURPOSE

The purpose of this review was to determine if there is an ideal operation for large symptomatic articular cartilage lesions on the undersurface of the patella in young patients.

METHODS

A systematic search of PubMed was conducted to determine the outcome of operations performed for large patellar lesions in young patients. Inclusionary criteria were English language, original clinical trials published from 1992 to 2012, patellar lesions 4 cm(2) or larger, mean patient age 50 years or younger, and all evidence levels.

RESULTS

Of 991 articles identified, 18 met the inclusionary criteria, encompassing 840 knees in 828 patients. These included 613 knees that underwent autologous chondrocyte implantation (ACI) (11 studies), 193 knees that had patellofemoral arthroplasty (PFA) (5 studies), and 34 knees that underwent osteochondral allografting (OA) (2 studies). The mean patient age was 37.2 years and the mean follow-up was 6.2 years. Long-term follow-up (>10 years) was available in only 4 studies (2 PFA, 1 ACI, 1 OA). All studies except one were Level IV and none were randomized or had a control group. Twenty-one outcome instruments were used to determine knee function. When taking into account knees that either failed or had fair/poor function, the percentage of patients who failed to achieve a benefit averaged 22% after PFA and 53% after OA and ranged from 8% to 60% after ACI. In addition, all 3 procedures had unacceptable complication and reoperation rates.

CONCLUSIONS

The combination of failure rates and fair/poor results indicated that all 3 procedures had unpredictable results. We concluded that a long-term beneficial effect might not occur in one of 3 ACI and PFA procedures and in 2 of 3 OA procedures. We were unable to determine an ideal surgical procedure to treat large symptomatic patellar lesions in patients 50 years or younger.

LEVEL OF EVIDENCE

Level IV, systematic review of Level I to IV studies.

The evaluation and management of cartilage lesions affecting the patellofemoral joint

Patellofemoral chondral lesions are unique and difficult-to-treat entities often affecting a young and active patient population. Recent advances in our understanding of cartilage injuries, surgical techniques, and surgical technology have provided treatment options for symptomatic patients with lesions of the patellofemoral compartment. A number of surgical treatment options are available, including surgical microfracture, autologous or juvenile chondrocyte implantation, osteochondral autograft transfer, and osteochondral allograft implantation. Management decisions are based on a number of patient- and lesion-related factors in an effort to relieve pain, restore function, and preserve the patellofemoral articulation. The present article reviews the evaluation and management of cartilage injuries affecting the patellofemoral joint.