Large Chondral Defects Research Articles

Osteochondral Allograft Transplantation: A Technical Note

Background: Chondral injuries in the knee are commonly discovered during knee arthroscopy procedures. Due to the poor restoration potential and avascular nature of cartilage, large defects are commonly treated with such surgical procedures. Treatment utilizing an osteochondral allograft (OCA) transplant for symptomatic focal cartilage defects in the patellofemoral joint has demonstrated strong, lasting clinical and radiographic outcomes. Indications: Active and otherwise healthy patients are indicated for surgery when presenting with significant joint-line pain and a large focal chondral defect verified on advanced imaging after an extensive course of nonoperative management. Technique Description: Beginning with diagnostic arthroscopy to confirm the large defect of the medial femoral condyle, we proceeded with OCA transplantation. A small medial peripatellar arthrotomy is performed. The fat pad is removed for visualization and retractors are placed both medially and laterally to appropriately visualize the defect. The defect is then sized according to the appropriate sizing guide. The guide is then placed perpendicular to the defect, and a central guide pin is drilled. A scoring reamer is used to carefully cut the size of the defect followed by a central reamer to prepare the defect. Any debris is removed, and the incision is thoroughly irrigated. The defect is then carefully measured in all four quadrants to match the donor. Any underlying bone is impacted for a stable base. A drill is then used for appropriate marrow venting underneath the defect. The corresponding donor site is selected and reamed with continuous irrigation to prevent thermal necrosis. The plug is removed and carefully measured to match the recipient site. The plug is thoroughly irrigated with pulse lavage to remove marrow elements. The graft is carefully inserted with gentle manual pressure until it is seated perfectly flush with the surrounding cartilage. Results: Clinical research has demonstrated good-to-excellent long-term survivorship of OCA transplantation. Long-term return to sport rates for recreational and competitive athletes are upward of 75%. Discussion/Conclusion: As surgical techniques continue to develop, surgeons should consider utilizing OCA transplants to treat large chondral defects in the patellofemoral joint. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Mid-term results of autologous matrix-induced chondrogenesis for large chondral defects in hips with femoroacetabular impingement syndrome.

The purpose of this study was to evaluate the mid-term outcomes of autologous matrix-induced chondrogenesis (AMIC) for the treatment of larger cartilage lesions and deformity correction in hips suffering from symptomatic femoroacetabular impingement (FAI). This single-centre study focused on a cohort of 24 patients with cam- or pincer-type FAI, full-thickness femoral or acetabular chondral lesions, or osteochondral lesions ≥ 2 cm2, who underwent surgical hip dislocation for FAI correction in combination with AMIC between March 2009 and February 2016. Baseline data were retrospectively obtained from patient files. Mid-term outcomes were prospectively collected at a follow-up in 2020: cartilage repair tissue quality was evaluated by MRI using the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score. Patient-reported outcome measures (PROMs) included the Oxford Hip Score (OHS) and Core Outcome Measure Index (COMI). Clinical examination included range of motion, impingement tests, and pain. A total of 12 hips from 11 patients were included (ten males, one female, mean age 26.8 years (SD 5.0), mean follow-up 6.2 years (SD 5.2 months)). The mean postoperative MOCART score was 66.3 (SD 16.3). None of the patients required conversion to total hip arthroplasty. Two patients had anterior impingement. External hip rotation was moderately limited in four patients. There was a correlation between MOCART and follow-up time (rs = -0.61; p = 0.035), but not with initial cartilage damage, age, BMI, or imaging time delay before surgery. PROMs improved significantly: OHS from 37.4 to 42.7 (p = 0.014) and COMI from 4.1 to 1.6 (p = 0.025). There was no correlation between MOCART and PROMs. Based on the reported mid-term results, we consider AMIC as an encouraging treatment option for large cartilage lesions of the hip. Nonetheless, the clinical evidence of AMIC in FAI patients remains to be determined, ideally in the context of randomized controlled trials.

Combined Trochlear, Patellar, Medial and Lateral Condyle Fresh Osteochondral Allograft Transplantation: A Case Report

Background: This is a case report of a 41-year-old man with torsional knee trauma in 2019 and chondral lesions. Previous microfracture had failed, and the patient presented with a dull pain and knee effusion. Imaging revealed multiple focal lesions including trochlea, patella, medial condyle, and lateral condyle. Fresh osteochondral allograft (OCA) transplantation is a versatile treatment for large defects as it is based on mature, living hyaline cartilage attached to a bone interface. A patient with multiple chondral lesions is rare, and this report presents a case with multiple symptomatic large focal lesions in the knee that underwent a fresh OCA in all 3 knee compartments. Indications: Osteochondral allograft is indicated for patients who present with activity-related pain and recurrent knee effusion. Contraindications are patient clinical conditions that may lead to complications, such as tobacco use, inflammatory arthritis, or septic arthritis. Technique Description: After the chondral defect is exposed, an appropriate allograft Mega-OATS sizer (15-30 mm) is chosen. Cartilage and the subchondral bone are drilled until the desired depth. The donor allograft is drilled in the desired diameter, and excess bone is removed according to the previous measurements of the recipient site. The graft is advanced with firm pressure into the created socket. Postoperative rehabilitation includes a limited range of motion and proprioceptive weightbearing in the first 2 weeks but expected total weightbearing and a full range of motion by the sixth week. Results: Range of motion was full by 6 weeks of surgery. The effusion lasted for 2 months after the surgery. Fresh OCA is a good surgical option for patients with multiple large chondral defects. Discussion/Conclusion: Patient satisfaction is high since the mature cartilage leads to a fast rehabilitation compared with the other surgical procedures for large chondral defects. This technique appears to be effective also for multiple focal lesions as presented in this article. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form.

Osteochondral Allografts in Knee Surgery: Narrative Review of Evidence to Date.

Knee articular cartilage defects can result in significant pain and loss of function in active patients. Osteochondral allograft (OCA) transplantation offers a single-stage solution to address large chondral and osteochondral defects by resurfacing focal cartilage defects with mature hyaline cartilage. To date, OCA transplantation of the knee has demonstrated excellent clinical outcomes and long-term survivorship. However, significant variability still exists among clinicians with regard to parameters for graft acceptance, surgical technique, and rehabilitation. Technologies to optimize graft viability during storage, improve osseous integration of the allograft, and shorten recovery timelines after surgery continue to evolve. The purpose of this review is to examine the latest evidence on treatment indications, graft storage and surgical technique, patient outcomes and survivorship, and rehabilitation after surgery.

Osteochondral Allograft Transplantation Of Posterior Femoral Condyle Lesions Utilizing An Open Posterior Approach To The Knee

Osteochondral allograft transplantation is a viable option for large chondral defects >2 cm squared, as well as in a revision setting after failure of a previous surface chondral restoration procedure. Osteochondral lesions involving the posterior aspect of the femoral condyle, however, are less common and easily underappreciated. Treatment of posterior osteochondral lesions is more technically demanding because they cannot be adequately addressed through standard arthroscopic approaches or an anterior arthrotomy. The challenges of the posterior approach include the relative unfamiliarity for many surgeons and the inherent risks due to the proximity of the neurovascular structures. The following technique reviews relevant anatomy and approach to osteochondral allograft transplant involving the posterior femoral condyles.

Humeral Head Resurfacing for Isolated Primary Humeral Osteoarthritis With a Large Chondral Defect

Primary, isolated humeral head arthritis or focal chondral defects are uncommon and difficult to diagnose preoperatively. While these lesions have traditionally been treated with total shoulder arthroplasty, shoulder hemiarthroplasty is a viable option for patients with isolated humeral head disease and minimal degenerative changes in the glenoid. This approach can be performed in a minimally invasive fashion, which preserves bone stock and native biomechanics, and can be beneficial if conversion to total shoulder arthroplasty is required in the future and avoids risk of glenoid loosening or failure in younger and more active individuals. In this Technical Note and accompanying video, we describe our technique of humeral head resurfacing in a patient with isolated primary humeral osteoarthritis with a large focal chondral defect in the humeral head.

Matrix-Induced Autologous Chondrocyte Implantation (MACI) is Largely Effective and Provides Significant Improvement in Patients With Symptomatic, Large Chondral Defects: A Systematic Review and Meta-Analysis.

The purpose of this study was to perform a meta-analysis for long-term patient-reported outcome (PRO) measures in Matrix-induced Autologous Chondrocyte Implantation (MACI) patients using the Knee Injury and Osteoarthritis Outcome Score (KOOS) model. A literature search under the PubMed/Medline and Embase databases was conducted. Statistical significance was determined between the mean pre- and postoperative scores at each time point (1-, 2-, and 5-years). Cohen's d analysis was used to measure the effect size (ES) in each group when compared to preoperative measurements to determine clinical responsiveness. KOOS subscales at all long-term postoperative follow ups measured in this study showed significant (p-value < 0.001) improvement when compared to preoperative scores. Furthermore, apart from KOOS sports and recreation (KOOS-SR) at 1-year postoperative follow up that showed a medium ES (ES, 0.761), all other KOOS subscales at long-term follow up periods showed a large (>0.8) ES on mean preoperative KOOS. Review of the literature demonstrate an absence of large meta-analyses for long-term PRO measures with the MACI procedure. It was found that all subscales were largely responsive when evaluated at >2 years after surgery. Based on these results, MACI is an effective treatment option for patients with symptomatic, full-thickness cartilage defects about the knee.

Bio-3D printing iPSC-derived human chondrocytes for articular cartilage regeneration

Osteoarthritis is a leading cause of pain and joint immobility, the incidence of which is increasing worldwide. Currently, total joint replacement is the only treatment for end-stage disease. Scaffold-based tissue engineering is a promising alternative approach for joint repair but is subject to limitations such as poor cytocompatibility and degradation-associated toxicity. To overcome these limitations, a completely scaffold-free Kenzan method for bio-3D printing was used to fabricate cartilage constructs feasible for repairing large chondral defects. Human induced pluripotent stem cell (iPSC)-derived neural crest cells with high potential to undergo chondrogenesis through mesenchymal stem cell differentiation were used to fabricate the cartilage. Unified, self-sufficient, and functional cartilaginous constructs up to 6 cm2 in size were assembled by optimizing fabrication time during chondrogenic induction. Maturation for 3 weeks facilitated the self-organisation of the cells, which improved the construct’s mechanical strength (compressive and tensile properties) and induced changes in glycosaminoglycan and type II collagen expression, resulting in improved tissue function. The compressive modulus of the construct reached the native cartilage range of 0.88 MPa in the 5th week of maturation. This paper reports the fabrication of anatomically sized and shaped cartilage constructs, achieved by combining novel iPSCs and bio-3D printers using a Kenzan needle array technology, which may facilitate chondral resurfacing of articular cartilage defects.

Role of Matrix-Associated Autologous Chondrocyte Implantation with Spheroids in the Treatment of Large Chondral Defects in the Knee: A Systematic Review.

Autologous chondrocyte implantation (ACI) is a cell therapy for the treatment of focal cartilage defects. The ACI product that is currently approved for use in the European Union (EU) consists of spheroids of autologous matrix-associated chondrocytes. These spheroids are spherical aggregates of ex vivo expanded human autologous chondrocytes and their self-synthesized extracellular matrix. The aim is to provide an overview of the preclinical and nonclinical studies that have been performed to ensure reproducible quality, safety, and efficacy of the cell therapy, and to evaluate the clinical data on ACI with spheroids. A systematic review was performed to include all English publications on self-aggregated spheroids of chondrocytes cultured in autologous serum without other supplements. A total of 20 publications were included, 7 pre- and nonclinical and 13 clinical research publications. The pre- and nonclinical research publications describe the development from concept to in vivo efficacy and quality- and safety-related aspects such as biodistribution, tumorigenicity, genetic stability, and potency. The evaluation of clinical research shows short- to mid-term safety and efficacy for the ACI with spheroid-based treatment of cartilage defects in both randomized clinical trials with selected patients, as well as in routine treatment providing real-world data in more complex patients.

Osteochondral Allograft Transplantation in Professional Athletes: Rehabilitation and Return to Play.

For the treatment of large chondral and osteochondral defects of the knee, osteochondral allograft transplantation (OCA) is an effective solution with relatively high rates of return to sport. In professional athletes, rehabilitation following OCA is a critical component of the process of returning the athlete to full sports activity and requires a multidisciplinary team approach with frequent communication between the surgical and rehabilitation teams (physical therapists, athletic trainers, coaching staff). In this review, we describe our five-phase approach to progressive rehabilitation of the professional athlete after OCA, which takes into account the biological processes of healing and optimization of neuromuscular function required for the demands of elite-level sport. The principles of early range of motion, proper progression through the kinetic chain, avoidance of pain and effusion, optimization of movement, regimen individuation, and integration of sports-specific activities underlie proper recovery.

Metrics of OsteoChondral Allografts (MOCA) Group Consensus Statements on the Use of Viable Osteochondral Allograft.

Background:Osteochondral allograft (OCA) transplantation has evolved into a first-line treatment for large chondral and osteochondral defects, aided by advancements in storage protocols and a growing body of clinical evidence supporting successful clinical outcomes and long-term survivorship. Despite the body of literature supporting OCAs, there still remains controversy and debate in the surgical application of OCA, especially where high-level evidence is lacking.Purpose:To develop consensus among an expert group with extensive clinical and scientific experience in OCA, addressing controversies in the treatment of chondral and osteochondral defects with OCA transplantation.Study Design:Consensus statement.Methods:A focus group of clinical experts on OCA cartilage restoration participated in a 3-round modified Delphi process to generate a list of statements and establish consensus. Questions and statements were initially developed on specific topics that lack scientific evidence and lead to debate and controversy in the clinical community. In-person discussion occurred where statements were not agreed on after 2 rounds of voting. After final voting, the percentage of agreement and level of consensus were characterized. A systematic literature review was performed, and the level of evidence and grade were established for each statement.Results:Seventeen statements spanning surgical technique, graft matching, indications, and rehabilitation reached consensus after the final round of voting. Of the 17 statements that reached consensus, 11 received unanimous (100%) agreement, and 6 received strong (80%-99%) agreement.Conclusion:The outcomes of this study led to the establishment of consensus statements that provide guidance on surgical and perioperative management of OCAs. The findings also provided insights on topics requiring more research or high-quality studies to further establish consensus and provide stronger evidence.

Management of Large Focal Chondral and Osteochondral Defects in the Knee.

Large, focal articular cartilage defects of the knee (> 4 cm2) can be a source of significant morbidity and often require surgical intervention. Patient- and lesion-specific factors must be identified when evaluating a patient with an articular cartilage defect. In the management of large cartilage defects, the two classically utilized cartilage restoration procedures are osteochondral allograft (OCA) transplantation and cell therapy, or autologous chondrocyte implantation (ACI). Alternative techniques that are available or currently in clinical trials include a hyaluronan-based scaffold plus bone marrow aspirate concentrate, a third-generation autologous chondrocyte implant, and an aragonite-based scaffold. In this review, we will focus on OCA and ACI as the mainstay in management of large chondral and osteochondral defects of the knee. We will discuss the techniques and associated clinical outcomes for each, while including a brief mention of alternative treatments. Overall, cartilage restoration techniques have yielded favorable clinical outcomes and can be successfully employed to treat these challenging large focal lesions.

One-Year MRI Outcomes of Osteochondral Allograft Transplantation of the Knee for Large Chondral Defects: Comparison of Elliptical, Stacked, and Single Allografts

Objectives:Osteochondral allograft transplantation (OCA) is a proven cartilage restoration procedure for patients with large chondral defects. However, elongated condylar lesions pose a challenge for dowel OCA in restoring articular surface congruity. Recently, instrumentation to harvest a single, elliptical allograft has been developed for treating ovoid lesions without requiring an adjacent-plug (stacked or snowman) technique. The purpose of this study was to compare 1-year MRI outcomes of patients treated with elliptical, stacked, or single OCA using the Osteochondral Allograft MRI Scoring System (OCAMRISS) and percent osseous integration.Methods:A retrospective review on patients treated from 2000 to 2018 with OCA for condylar defects of the knee was conducted. Inclusion criteria included those followed prospectively with a MRI at ˜1 year after surgery. OCAMRISS and osseous integration scores (0-25%; 26-50%; 51-75%; 76%-100%) were graded by a musculoskeletal radiologist blinded to the outcomes. Comparisons of demographics and MRI scores were performed with the ANOVA.Results:A total of 57 knees (mean age, 35.8 years; 70% male) met the inclusion criteria and were treated with either elliptical (n=19), stacked (n=19), or single (n=19) OCA. Mean time to post-operative MRI was 10.7, 11.1, and 12.4 months, respectively (p=0.17). There were no significant differences in demographics or number of prior ipsilateral knee surgeries among groups. Defect characteristics were significantly different between groups, where single plugs treated a higher percentage of LFC defects (58%) compared to elliptical and stacked (26%, each) (p=0.02). Total chondral defect area was greatest in the stacked group (5.4 ± 1.3) compared to elliptical (4.6 ± 1.2) and single (4.6 ± 1.4) (p=0.12). Bone, cartilage, ancillary, and total OCAMRISS scores were not significantly different between groups. A trend towards a higher percentage of osseous integration (single>stacked>elliptical) was noted which correlated with less transplanted allograft bone, however, these differences were not significant (p=0.15).Conclusion:One-year OCAMRISS and osseous integration scores did not differ among patients treated with elliptical, stacked, or single OCA. Further investigation is needed to explore potential differences in clinical outcomes and long-term osseous integration between elliptical and stacked OCA for the treatment of elongated condylar defects of the knee.Table 1.Patient Demographics, Intraoperative Data, and OCAMRISS Scores at 1-year Postoperative MRI Elliptical (n = 19) Stacked (n = 19) Single (n = 19) P Value Patient CharacteristicsAge, y37.0 ± 13.937.5 ± 11.133.1 ± 11.80.48Sex (male/female), n14/513/613/60.92Body mass index, kg/m2 25.7 ± 2.826.5 ± 5.025.9 ± 3.20.78No. of prior ipsilateral knee surgeries1.1 ± 1.41.9 ± 2.41.4 ± 0.80.29MRI follow-up, mo10.7 ± 3.911.1 ± 1.912.4 ± 2.20.17Lesion CharacteristicsOCA location, n (%)0.02Medial femoral condyle14 (74)14 (74)8 (42)Lateral femoral condyle5 (26)5 (26)11 (58)Total chondral defect area, cm2 4.6 ± 1.25.4 ± 1.34.6 ± 1.40.12OCAMRISS ScoreCartilage features3.5 ± 1.52.9 ± 1.53.4 ± 2.10.48Bone features3.0 ± 0.72.7 ± 0.72.8 ± 0.60.30Ancillary features3.0 ± 1.12.9 ± 1.02.6 ± 1.10.46Total9.5 ± 2.18.4 ± 2.58.8 ± 3.10.45Osseous Integration Score2.1 ± 1.11.7 ± 0.901.5 ± 0.600.15

Particulate Juvenile Articular Cartilage vs Osteochondral Allograft for Patellar Cartilage Defects: A Matched Cohort Analysis

Objectives:Management of full-thickness cartilage defects of the patella remains a significant clinical challenge. Osteochondral allograft transplantation (OCA) is a reliable cartilage restoration procedure for large chondral defects of the knee. OCA reports good long-term outcomes for condylar defects but limited literature on outcomes of patellar defects. Since 2007, particulated juvenile articular cartilage (PJAC) has been used as an alternative method of cartilage restoration. PJAC has demonstrated promising early clinical outcomes, however, no studies have directly compared the clinical and patient reported outcomes of PJAC and OCA for management of full thickness chondral defects of the patella.Methods:Prospective data was collected for patients within our institutional cartilage registry who underwent OCA or PJAC using DeNovo NT (Zimmer-Biomet) for management of grade 4 cartilage defects of the patella. OCA patients were matched to PJAC patients by age, sex and BMI. Patient characteristics and minimum 2-year patient reported outcomes (PROMs) (Knee Outcome Survey-Activities of Daily Living (KOS-ADL) score, International Knee Documentation Committee (IKDC) score, Short Form 36 (SF-36) pain rating, and Marx Activity Rating Scale) and self-reported general overall knee condition were reported.Results:There were 28 patients eligible for analysis (14 OCA, 14 PJAC). Demographics of the two groups are outlined in Table 1. The mean age of the entire cohort was 38.4 +/- 11.4 years with a mean BMI of 24.6 +/- 3.1. One patient in each group had bipolar transplantation (patella and trochlea). OCA patients had more previous surgeries (1.4 vs 0.4) (p<0.01) and significantly larger chondral defects (4.6 cm2 vs. 2.5 cm2) (p<0.01) than PJAC patients.Patient reported outcomes are reported in Figure 1. IKDC, KOS-ADL and SF-36-Pain scores improved by 17, 16 and 14 points for OCA compared to 17, 11, and 23 points for PJAC at last follow-up (average 3.5 years) (p>0.05). Both groups met the published MCID for IKDC (17 pts) and KOS-ADL (10 pts) for osteochondral grafts. There was no significant difference between OCA and PJAC for all postoperative PROMs. The reoperation rate for OCA and PJAC was 36% and 50% respectively (p>0.05). There were 4 graft failures in the PJAC group (29%) and 1 failure in the OCA group (6%) (p>0.05). The failed OCA underwent manipulation and lysis of adhesions for post-operative stiffness at 7 months and arthroscopic synovectomy for synovitis at 8 months after OCA. The four failed PJAC patients underwent revision to OCA (at 8 months), chondroplasty of the graft (at 10 and 26 months), and revision to TKA (at 78 months). Reoperations are further described in Table 2. Conclusion: In a matched cohort analysis, both PJAC and OCA demonstrated significant clinical improvement in patient reported outcomes with no significant difference between the two groups at mean 3.5 years. Larger investigational studies are needed to determine optimal indications for use of PJAC versus OCA for management of focal cartilage defects of the patella.Table 1.Patient Characteristics by Group OCA PJAC P value Age (y)39.137.80.77Sex (M:F)4:104:101BMI24.424.80.77Mean # of Prior Surgeries1.430.360.0038Defect Area ()4.602.480.0007Defect Location (Coronal) (n)Central Third-10Medial Facet- 1Lateral Facet- 3Central Third- 7Medial Facet- 5Lateral Facet- 2NA Concomitant Procedures (n)Tibial tubercle transfer- 2Distal femoral osteotomy- 1MPFL reconstruction- 1Tibial tubercle transfer- 5MPFL reconstruction-1NATable 2.Reoperations and Graft Failures for PJAC and OCAPJAC (7 Patients)Time from surgery (mos)OCA (5 patients)Time from Surgery (mos)MUA2MUA, lysis of adhesions, fat pad debridement, anterior capsular release 7OCA patella, tibial tubercle transfer*7I&D and synovectomy *8Chondroplasty patella (grade III/IV changes of graft); fat pad excision, patella tendon release*10HWR tibial tubercle11HWR tibial tubercle16HWR distal femur19HWR tibial tubercle, fat pad excision, patellar tendon release, Chondroplasty medial femoral condyle23Tibial tubercle transfer; OCA patella (15 mm graft)**58Chrondoplasty patella (grade III/IV changes of graft); HWR tibial tubercle*26Lysis of adhesions, medial meniscectomy, HWR tibial tubercle74Total knee replacement*78 *Graft failure Same patient** performed in different location; previous OCA was intactHWR=hardware removal; I&D= irrigation and debridement; MUA=manipulation under anesthesia

Promising radiological outcome after repair of acetabular chondral defects by microfracture augmented with chitosan-based scaffold: mid-term T2 mapping evaluation.

Radiological evaluation of the repair tissue produced after arthroscopic treatment of acetabular chondral lesions associated with femoroacetabular impingement (FAI) by the chitosan-based scaffold. Patients of age 18-55years with clinical and radiological features of FAI and non-arthritic non-dysplastic hips were selected for arthroscopic treatment. Full-thickness acetabular chondral defects were filled with chitosan-based scaffold material after microfracture. T2 mapping was carried out for all patients after 24months using a 1.5-T machine. Nine regions of interest (ROIs) were localized from three consecutive sagittal slices including the area of repair. T2 relaxation times of ROIs in the repair area were compared with the corresponding posterior cartilage. Twenty-one patients, 17 men and 4 women, underwent arthroscopic treatment of full-thickness acetabular chondral defects with mean size of 3.6 ± 1cm2 (range 2-6cm2). Zone 2 was affected in all cases while zone 3 was involved in 13 cases. T2 relaxation values were collected from 189 ROIs for quantitative analysis. Within the peripheral repair area, the mean T2 value was 49.1 ± 7.2ms (ms), while ROIs of the central repair area had mean T2 values of 50.2 ± 7.1ms. Posterior cartilage showed mean T2 value of 46.2 ± 7.6ms CONCLUSION: Arthroscopic microfracture of large full-thickness acetabular chondral defects with chitosan-based scaffold produced a homogenous repair tissue similar to the corresponding native cartilage of the same joint on quantitative T2 mapping at mid-term follow-up. augmentation of the microfracture by chitosan-based scaffold is a promising modality for treatment of large full-thickness acetabular defects. IV.

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.

Large chondral defect not covered by meniscal allograft is associated with inferior graft survivorship after lateral meniscal allograft transplantation.

This study aimed to evaluate graft survivorship according to the size and location of chondral defects and its effect on clinical outcomes after meniscal allograft transplantation (MAT). It was hypothesized that large chondral defects would be associated with inferior outcomes. Patients who underwent lateral MAT with fresh-frozen allografts between 2007 and 2016 were retrospectively reviewed. The inclusion criteria were patients with femoral or tibial chondral defects (International Cartilage Repair Society grade 4) who were followed up more than 2years with 3.0-T magnetic resonance imaging (MRI) scans. Maximal lesion diameter and location were assessed on MRI. The patients were divided into two groups, with chondral defects of < 3 and ≥ 3 cm2 on the tibial side. Graft survivorship was compared between the two groups. Graft failure was defined as revisional MAT, meniscal tear or meniscectomy greater than one-third of the allograft on MRI. Clinical outcomes were evaluated using the modified Lysholm score. Twenty-eight knees in 26 patients (mean age 37.4 ± 10.3years) with a mean follow-up of 3.6 ± 1.0 (range 2.0-5.4) years were identified. Nineteen knees in 17 patients had both femoral and tibial chondral defects, 7 knees in 7 patients had only femoral chondral defects, and 2 knees in 2 patients had only tibial chondral defects. The mean preoperative femoral and tibial chondral defect sizes were 1.7 ± 1.2 and 3.0 ± 1.4 cm2, respectively. Among the seven graft failures, no graft failure occurred in the cases with tibial chondral defects of < 3 cm2. Tibial chondral defects of ≥ 3 cm2 were significantly associated with graft failure (P = 0.004; odds ratio 28.3; 95% confidence interval 2.5-4006.7). Defects of < 3 cm2 were located primarily in the posterior aspect of the lateral tibial plateau, and most lesions were covered by allograft (7/9, 77.8%). The modified Lysholm scores significantly improved irrespective of chondral defects size (P < 0.001). Larger chondral defects, more than 3 cm2 on the tibial side, were associated with inferior graft survivorship but did not influence the clinical outcomes after MAT at the 3.6-year follow-up. Chondral defect location was associated with defect size. IV.

Osteochondral Allograft Cartilage Transplantation for a Full-Thickness Femoral Condyle Chondral Lesion.

Cartilage lesions of the knee pose a difficult challenge for orthopaedic surgeons. Osteochondral allograft transplantation is an option in the setting of large chondral or osseous defects, or after failure of other treatment options1-3. The use of allograft offers the benefit of utilizing both viable hyaline cartilage and bone4. Fresh allografts are usually transplanted into the femoral condyle, although they can also be used in the patella, tibial plateau, or femoral trochlea1. Research has shown that patients who undergo this procedure for the treatment of focal and diffuse chondral defects have favorable outcomes and satisfaction scores1. The procedure is performed as follows. (1) Preoperative evaluation: patients are evaluated for a cartilage procedure after obtaining history, examination, and imaging (radiographs and magnetic resonance imaging). (2) Approach: a longitudinal parapatellar tendon arthrotomy is performed. (3) Debridement: the lesion is identified, and unstable cartilage is debrided back to stable cartilage. (4) Measure defect: the recipient site depth is measured in 4 positions, as on the face of a clock (12, 3, 6, and 9 o'clock). (5) Template allograft: a sizer is used to template the allograft hemicondyle. (6) Secure and harvest allograft: the allograft is secured in the Osteochondral Allograft Transplantation Surgery (OATS) Workstation (Arthrex) and harvested from cadaver bone. (7) Measure depth: the recipient depth measurements are marked on the allograft. (8) Cut graft: the graft is held with allograft-holding forceps while graft is cut with a saw. (9) Check measurements: allograft measurements are checked to ensure that they match recipient measurements. (10) Round edges: the osseous ends are rounded to assist with insertion of graft. (11) Irrigate: the allograft is irrigated after final cuts. (12) Graft insertion: the graft is inserted after lining up the 12-o'clock position recipient and donor reference marks and is held in place with a press fit. (13) Closure: standard closure in layers is performed.

OSTEOCHONDRAL ALLOGRAFT TRANSPLANTATION for the KNEE: POST-OPERATIVE REHABILITATION.

Articular cartilage injuries of the knee are common among young, active patients presenting with knee pain, swelling, and/or mechanical symptoms. These injuries have limited healing potential due to the avascular nature of hyaline cartilage. While several treatment options exist, osteochondral allograft (OCA) transplantation for the knee has been used successfully in primary management of large chondral or osteochondral defects and salvage of previously failed cartilage repair. OCA transplantation potentially yields a natural, matching contour of the native recipient surface anatomy and transplants mature, viable hyaline cartilage to the affected defect. Following OCA transplantation, strict compliance with a rehabilitation protocol is essential to enable optimal recovery. The outlined rehabilitation protocol is informed by the existing literature and incorporates current rehabilitation principles, the science of osteochondral incorporation, and adaptations based on an individual's readiness to progress through subsequent phases. The purpose of this clinical commentary is to discuss the diagnosis, surgical management, and post-operative rehabilitation following OCA transplantation and to assist the physical therapist in returning athletes to full sports participation.

Do Larger Acetabular Chondral Defects Portend Inferior Outcomes in Patients Undergoing Arthroscopic Acetabular Microfracture? A Matched-Controlled Study

To elucidate the effect, if any, of acetabular chondral defect size on surgical outcomes after arthroscopic microfracture was performed with concomitant treatment for labral tears and femoroacetabular impingement (FAI) syndrome. The study period was between February 2008 and November 2014. Data were collected on patients who underwent hip arthroscopy. The inclusion criteria were acetabular microfracture; concomitant treatment for labral tears and FAI syndrome; and preoperative modified Harris Hip Score, Nonarthritic Hip Score, Hip Outcome Score-Sports Specific Subscale, and visual analog scale. Exclusion criteria were Workers' Compensation, preoperative Tönnis grade >1, or previous ipsilateral hip surgeries or conditions. Patients were grouped based on smaller chondral defects (SCDs) or larger chondral defects (LCDs), then matched 1:1 by age at surgery ±10years, sex, body mass index ±5, labral treatment, capsular treatment, acetabuloplasty, and femoroplasty. Outcomes, secondary arthroscopies, and conversions to total hip arthroplasty (THA) were documented. Of 131 eligible cases, 107 (81.7%) had minimum 2-year follow-up. Before matching, the conversion rate to THA was higher for LCDs (24.6%) than for SCDs (12.0%). Thirty-five patients were matched for each group. Mean follow-up time was 47.9months (range, 24.0, 84.1) for the matched LCD group and 46.1months (range, 24.0, 88.1) for the matched SCD group. Ligamentum teres debridement (P= .03) was performed more frequently in the LCD group. No other differences were found regarding demographics, intraoperative findings, procedures, traction time, preoperative scores, or follow-up scores. Both groups demonstrated significant improvements in all scores. Rates of revision or conversion to THA were similar between groups. The relative risk for conversion to THA was 2.33 for patients with defects ≥300mm2 compared with patients with defects ≤250mm2 (P= .13). Deep vein thrombosis occurred in 3 (5.3%) patients with LCDs. Matched patients with either SCDs or LCDs undergoing arthroscopic acetabular microfracture with concomitant treatment for labral tears and FAI syndrome demonstrated similar improvements at minimum 2-year follow-up. Patients with chondral defects approaching 300mm2 or greater may have a higher propensity toward conversion to THA. Level III, retrospective comparative therapeutic trial.