Particulated Juvenile Articular Cartilage Research Articles

Rate of Conversion to Matrix-Induced Autologous Chondrocyte Implantation After a Biopsy: A Multisurgeon Study

Autologous chondrocyte implantation (ACI) and matrix-induced autologous chondrocyte implantation (MACI) are performed to treat focal chondral defects (FCDs); both are 2-step procedures involving a biopsy, followed by transplantation. There is little published research evaluating ACI/MACI in patients who undergo a biopsy alone. To determine (1) the value of ACI/MACI cartilage biopsies and concomitant procedures in patients with FCDs of the knee and (2) the conversion rate to cartilage transplantation as well as the rate of reoperation. Case series; Level of evidence, 4. A retrospective review was performed of 46 patients (63% female) who underwent a MACI (or ACI) biopsy between January 2013 and January 2018. Preoperative data, intraoperative data, and postoperative outcomes were assessed at a minimum of 2 years after the biopsy. The conversion rate from a biopsy to transplantation and the reoperation rate were calculated and analyzed. Among the 46 patients included, 17 (37.0%) underwent subsequent surgery, with only 12 undergoing cartilage restoration surgery, for an overall transplantation rate of 26.1%. Of these 12 patients, 9 underwent MACI/ACI, 2 underwent osteochondral allograft transplantation (OCA), and 1 underwent particulated juvenile articular cartilage implantation at 7.2 ± 7.5 months after the biopsy. The reoperation rate was 16.7% (1 patient after MACI/ACI and 1 patient after OCA) at 13.5 ± 2.3 months after transplantation. Arthroscopic surgery with debridement, chondroplasty, loose body removal, meniscectomy/meniscal repair, and other treatment approaches of knee compartment abnormalities at the time of a biopsy appeared to be sufficient in improving function and reducing pain in patients with knee FCDs.

Combined MPFL Reconstruction with Tibial Tubercle Osteotomy and Repair of Patellar Cartilage Defect with Particulated Juvenile Articular Cartilage.

Combined MPFL Reconstruction with Tibial Tubercle Osteotomy and Repair of Patellar Cartilage Defect with Particulated Juvenile Articular Cartilage.

Long-term Patient-Reported Outcome Measures Following Particulated Juvenile Allograft Cartilage Implantation for Treatment of Difficult Osteochondral Lesions of the Talus.

Conventional methods are not suitable for difficult to treat osteochondral lesions of the talus (OCLTs). The role of particulated juvenile allograft articular cartilage implantation is not well elucidated for long-term patient outcomes. Thirteen patients with difficult-to-treat OCLTs underwent arthroscopy-assisted implantation of particulated juvenile articular cartilage graft into defects from 2010 to 2012 by the same surgeon. "Difficult to treat" was defined as having at least 3 of the following features or 2 if both variables described lesion characteristics: (1) lesions size of 107 mm2 or greater, (2) shoulder lesions, (3) patients who failed microfracture, (4) patient aged ≥40 years, or (5) patient body mass index (BMI) >25. Patients were evaluated using physical examination, patient interviews, and outcome score measures. Patients had follow-up at 2 years, 4 years, and between 6 and 10 years at their most recent follow-up. Differences in functional outcome scores were compared before and after surgery. Patients (age: 46.5 ± 11.8 years, BMI: 28.5 ± 6.1) had, on average, most recent follow-up of 8.0 years (range 72-113 months). Average visual analog scale for pain score decreased for patients by 3.9 points (95% confidence interval [CI] 2.18-5.60), when compared to preoperative assessment. Foot and Ankle Ability Measure (FAAM) Activities of Daily Living (ADL) and Sports subscale scores also improved from 46.5 to 80.9 (95% CI 21.35-47.43), and from 18.8 to 57.9 (95% CI 21.05-57.10), respectively. Short Form-36 Health Survey physical component scores showed significant improvement by an average of 45.5 points (95% CI 32.42-58.50). American Orthopaedic Foot & Ankle Society Ankle-Hindfoot Scale scores improved from 55.2 to 80.3 (95% CI 12.459-37.741). These results demonstrate positive patient-reported long-term outcomes for a cohort of patients with difficult OCLTs, followed over the course of 6-10 years after treatment with arthroscopy-assisted particulated juvenile articular cartilage implantation. Level II, prospective cohort study.

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

There is currently no evidence-based consensus on how to treat a full-thickness, symptomatic articular cartilage injury of the patella, although numerous treatment options are available. To systematically evaluate the functional outcomes after operative treatment of patellar cartilage lesions. Our secondary purpose was to evaluate radiographic outcomes after treatment. PubMed, Cochrane, and Embase. Studies published between January 1, 1990 and December 31, 2018 that included patient-reported functional outcomes for patients after operative treatment of patellar chondral defects at a minimum 2-year follow-up were included. Systematic review. Level 4. MINORS (Methodological Index for Non-Randomized Studies) score, level of evidence, sample size, demographic data, follow-up data, intervention, functional outcome scores, and magnetic resonance imaging (MRI) data were collected. The review identified 10 studies and 293 patients receiving cartilage restoration procedures for patellar chondral defects with extractable clinical and radiographic results and data on complications and reoperations. All treatments (autologous chondrocyte implantation [ACI], matrix-induced ACI [MACI], autologous osteochondral transplantation [AOT]) utilized in the management of patellar chondral lesions, with the exception of isolated particulated juvenile articular cartilage, demonstrated statistically significant improvements in functional outcome scores compared with preoperative measurements at a minimum of 2-year follow-up. Postoperative MRIs were obtained in 6 studies and found that regardless of treatment, moderate-to-complete infill of patellar cartilage lesions was seen in the majority of patients. While failure rates were low for the various treatment modalities, rates of reoperation were substantial, with up to 40% to 60% reoperation rate seen after ACI. Patients treated with ACI, MACI, and AOT all demonstrated statistically significant improvements in functional outcome scores with radiographic evidence of healing at minimum of 2-year follow-up. Evidence is insufficient to recommend one particular treatment over another.

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

Particulated Juvenile Articular Cartilage (PJAC) Allograft for Treatment of Lateral Femoral Condyle defect in High-Performance Athletes

Background: A relatively new technology for the treatment of high grade articular cartilage lesions is the implantation of particulated articular cartilage obtained from a juvenile allograft donor (PJAC).1-2 Previous studies have reported the ability of juvenile chondrocytes to migrate from cartilage explants after being secured in a cartilage defect.3 There is little in the literature to use as a reference with respect to the use of PJAC for high grade articular cartilage lesion of the lateral femoral condyle after a failure of treatment with a microfracture in the high level athlete. Objective: The aim of this report is to describe the technique of PJAC transplantation for the treatment of chondral lesions of the lateral femoral condyle and to report the short term outcomes in the high performance athlete. Methods: We present a case report of two patients who were treated in our clinic in December 2014. Case 1: 16 year old female Division 1 university soccer player, who one year prior to our index surgery underwent microfractures of a symptomatic lateral femoral condyle articular cartilage lesion without relief. Cae 2: 29 year old male professional tennis player (case 2) with a recurrent, symptomatic chondral defect on the lateral femoral condyle. The player had undergone multiple arthroscopic procedures on the same knee following an injury sustained while playing in the Australian Open, including a surgery 8 months prior to our index operation that had included lateral meniscal tear repair and microfractures. PJAC procedure consists of a minimal debridement and chondroplasty, performed arthroscopically. For these central lateral femoral condyle lesions, a mini-arthrotomy is created along the lateral parapatellar longitudinal axis over a length of about 3 cm. With the chondral defect localized and prepared, a thin fresh layer of fibrin glue is then applied. The PJAC graft is equally distributed in the defect with space in between the fragments so as not over-fill the defect. Then, a new fibrin glue layer is placed to cover the graft. The overall construct remains just below the level of the normal articular surface. The knee is cycled through the range of motion to ensure that the tissue construct is stable. We present images of the cartilage defect after debridement and the allograft implantation procedure. In addition we will submit an instructional video performed on a knee specimen. Results: Outcomes measured were: IKDC, Lysholm, and Tegner knee scores together with arc of motion of the joint. After 28 months follow up, patients had gained complete range of motion and significantly decreased pain. Improvement for each outcome measure used is reported. Conclusions: PJAC transplantation offers pain relief and improved short term outcomes in high level performance athletes. Both of our patients are back to practicing their sport with notable improvement in symptoms. No complications have been noted. Long-term data is not yet available.

Patellofemoral Cartilage Lesions Treated With Particulated Juvenile Allograft Cartilage: A Prospective Study With Minimum 2-Year Clinical and Magnetic Resonance Imaging Outcomes

To analyze the functional outcomes of patients treated with particulated juvenile articular cartilage (PJAC) for symptomatic articular cartilage lesions in the patellofemoral joint, correlates clinical outcomes with magnetic resonance imaging (MRI) appearance of the repair tissue using cartilage-sensitive quantitative T2-mapping. All patients treated with PJAC for patellofemoral lesions were identified and prospectively followed with clinical outcome scores (International Knee Documentation Committee [IKDC], Knee Outcome Survey-Activities of Daily Living [KOS-ADL], and Marx Activity Scale [MAS]). Postoperative MRI scans using quantitative T2 mapping were obtained and interpreted by an independent musculoskeletal radiologist. Twenty-seven patients treated with PJAC for 30 full-thickness patellofemoral cartilage lesions were identified; mean postoperative follow-up was 3.84years. Improvements from pre- to postoperative mean IKDC (45.9 vs 71.2, P < .001) and KOS-ADL (60.7 vs 78.8, P < .001) scores were observed; no significant change in MAS was seen (7.04 vs 7.17, P= .97). Advanced age, history of previous surgery, lesion location (patella vs trochlea), or concomitant tibial tubercle osteotomy did not affect outcome scores. Greater body mass index was associated with less improvement in KOS-ADL score. No patients required reoperation for graft-related issues. Lesion fill exceeding 67% by MRI assessment was noted in 69.2% of lesions; depth of lesion fill did not correlate with clinical outcomes. Quantitative T2-mapping revealed prolonged relaxation time at the graft site compared with adjacent normal cartilage at both deep and superficial zones. This study found significantly improved pain and function in patients treated with PJAC for symptomatic patellofemoral articular cartilage defects. No patients required reoperation for graft-related issues. Postoperative MRI revealed majority lesion fill in more than 69% of patients, but persistent morphologic differences between graft site and normal adjacent cartilage remain. Though we support PJAC use in this setting to improve patient subjective outcomes, improved appearance on postoperative imaging was not found to provide additional clinical benefit. Level IV, case series.

First Metatarsal Head Osteochondral Defect Treatment With Particulated Juvenile Cartilage Allograft Transplantation: A Case Series.

Focal damage to articular cartilage, also called an osteochondral defect (OCD), can be a cause of pain and decreased range of motion. Recent advancements have led to transplantation techniques using particulated juvenile articular cartilage allograft. This technique has been applied to the first metatarsal head to a very limited degree, with no published results to our knowledge. The aim of this study was to review the clinical results of patients who underwent particulated juvenile cartilage allograft implantation for first metatarsal head OCDs. We performed a retrospective consecutive case series study. Nine patients, at an average age of 41 years, were treated for symptomatic focal osteochondral defects of the first metatarsal head with particulate cartilage grafting from 2010 to 2016. Patients were contacted by phone to assess interest in returning to the office for follow-up, where weightbearing radiographs of the foot were obtained and a foot examination was performed. At an average follow-up of 3.3 years, 7 of 9 patients reported no pain with recreational activities and no patient required further operations. This patient cohort was physically active, with 6 of 9 listing running as a regular activity. The average overall American Orthopaedic Foot & Ankle Society (AOFAS) Hallux Metatarsophalangeal-Interphalangeal Scale questionnaire score was 85 (maximum 100), AOFAS pain 35.6 (maximum 40), and AOFAS function 40.1 (maximum 45). Patient satisfaction surveys correlated with the AOFAS scores and revealed that 7 of 9 patients were very satisfied with their results, 1 was satisfied, and 1 patient was very dissatisfied. Particulated juvenile cartilage allograft transplantation is a promising treatment option for symptomatic first metatarsophalangeal focal articular cartilage lesions. Further study is needed to demonstrate which lesions respond better to this type of cartilage graft versus traditional marrow-stimulating procedures. Level IV, retrospective case series.

Comparing Treatment Options for Large Talar Osteochondral Lesions

Category: Ankle, Arthroscopy, Sports Introduction/Purpose: The surgical treatment of large or revision osteochondral (OCD) lesions of the talus remain challenging. Currently, there are several treatment options for these patients, including: osteochondral autograft (OATS), allograft cartilage extracellular matrix (Arthrex BioCartilage), and particulated juvenile articular cartilage allograft (Zimmer DeNovo). Due to the relative rarity of these procedures, the literature comparing these three modalities is scarce. The aim of this study was to assess midterm clinical outcomes after these surgical treatments for large or revision talar OCD lesions. Methods: Hospital IRB approval was obtained. We reviewed surgical case logs and identified 78 total patients between 2003- 2015 for inclusion in this retrospective study. Thirty-three patients were excluded due to incomplete preoperative or postoperative outcome scoring data, and 23 patients are pending followup, leaving a cohort of N = 22 patients (5 OATS, 5 DeNovo, 12 BioCartilage). Functional outcomes preoperatively and postoperatively were evaluated using Short Form 12-item Physical and Mental Health Survey (SF12 M and SF12P) and Foot Function Index (FFI) scores, ability to return to sport or work, and the need to return to the OR for revision surgery. Data were compared using paired student’s t-test and a one way ANOVA. Results: Mean age was 38y with mean followup of 4.3y (range 1.1-12.5). Of 22 patients, three were revisions. Mean lesion size was (12.6x9.1x6.5 mm). All groups showed significant improvements in FFI (p &lt; 0.05) compared to preoperative baseline. Only the BioCartilage group showed significant improvement in SF12P (37.6 vs 47.8, p&lt;0.05). The OATS and DeNovo groups did not show a significant increase in SF12P, and none of the groups demonstrated significant improvement in SF12 M. All patients returned to work, and 8/11 (73%) athletes returned to sport. There were no significant differences between groups when comparing SF12, FFI, and return to sport/work. Revision surgery was necessary in 6/22 (28%) patients. Post-hoc power analysis revealed limited power (0.23), and effect size (f=0.32) may be due to small sample size. Conclusion: All three treatment methods resulted in good medium-term functional results for the treatment of large or revision talar OCD lesions. However, we were unable to distinguish significant differences between OATS, Biocartilage, and Denovo, likely due to small cohort numbers and low power. Further study is warranted with increased patient numbers to improve power and differentiate among the three treatment options, as well as provide longer clinical and radiographic follow-up.

Mid-Term Results of Particulated Juvenile Articular Cartilage Allograft Transplantation to the Knee

Objectives:Full-thickness chondral defects of the knee in the young, active patient remain a concerning orthopedic entity given the low capacity for natural regeneration of articular cartilage and limited established treatment options. In the knee, transplantation of particulated juvenile articular cartilage (Zimmer DeNovo NT) has been shown in small studies with only short-term outcomes to have excellent potential. This is the first study that has followed patients greater than 2 years.Methods:All patients at a single institution who underwent a DeNovo NT cartilage transplant procedure for single or multiple lesions of the knee between 2010 and 2014 were identified. All patients had an MRI pre-operatively. Size and location of defects treated were recorded intra-operatively, as were all concomitant procedures. MRI was performed at a minimum of 6 months post-operatively. MRIs were all read by musculoskeletal radiologists and repair tissue evaluated by the MOCART (Magentic Resonance Observation of Cartilage Repair Tissue) score. All patients were administered the Lysholm questionnaire pre and postoperatively.Results:26 patients (28 knees) were identified, 17:9 M:F, and average age 33.7 years (21-49 years). A total of 34 Outerbridge grade IV cartilage lesions were treated, 10 lesions on the MFC, 6 on the LFC, 13 on the patella and 5 on the trochlea. Average cross sectional area of the lesions was 3.075 cm2; average area of MFC lesions was 2.844cm2, LFC 2.69 cm2, patellar lesions 3.795cm2, and trochlea lesions 2.195 cm2. Associated procedures included patellar realignment in 16/28 (tibial tubercle osteotomy in 12, VMO advancement in 4); 6 MPFL reconstructions and 10 lateral releases. ACL reconstruction occurred in 7/28 knees and partial meniscectomy in 9. There were 11 returns to the OR, 3 for MUA, 9 for arthroscopic debridement (including 5 hypertrophic graft tissue, 1 loose body and 2 further microfractures of a prior or new lesion). On MRIs at 6 months post-op. The average MOCART score was 54.7 (range 20-85). 12/17 had fill of the defect, 3 had >50% fill; 10 had full border integration and 5/17 were isointense on T2. More than half of patients with greater than 1 post-operative MRI showed a progressive increase in their MOCART score with increasing time since surgery. Average pre-op Lysholm score was 51.99 (SD 15.24, range 29.17-68.76). At an average of 4.8 years post-operatively, the mean Lysholm was 86.37 (SD 10.72, range 70.84-100). This improvement in Lysholm scores was statistically significant, p< 0.001.Conclusion:This study clearly shows that this particulated juvenile cartilage transplant procedure has good short term and lasting results. MRI findings confirm that it achieves good ingrowth and integration. In our analysis, there is a trend towards increasing MOCART scores with time, but this did not reach statistical significance. This is the first study that confirms excellent outcomes following DeNovo NT cartilage transplantation in the knee are maintained at a mid-term follow up of nearly 5 years.

Combined Particulated Juvenile Cartilage Allograft Transplantation and Medial Patellofemoral Ligament Reconstruction for Symptomatic Chondral Defects in the Setting of Recurrent Patellar Instability

Successful management of patellar osteochondral lesions has proved difficult, with unreliable outcomes reported using traditional cartilage repair and restoration procedures. Unique considerations for this type of defect include the multiplanar contours of the articular surface of the patella, high compressive and shear forces with knee range of motion that may disrupt graft healing, and the potential need for concomitant surgery to address patellar malalignment and instability. We describe our preferred method for treatment of a symptomatic chondral defect in the setting of recurrent patellar instability using particulated juvenile articular cartilage allograft transplantation and medial patellofemoral ligament reconstruction with semitendinosus allograft. Distinct advantages of this cartilage restoration technique include single-stage restoration of relevant cartilage pathology and the ability to easily contour the graft to the size and shape of the chondral defect.

Arthroscopic treatment of talus osteochondral lesions with particulated juvenile allograft cartilage.

Osteochondral lesions of the talus (OLT) are commonly associated with traumatic injury to the ankle joint. Treatment options depend on the grade, location, and size of the lesion. Operative intervention is frequently required with initial management involving marrow stimulation techniques, such as microfracture/curettage. Larger lesions often require a secondary procedure, such as osteochondral transplantation or autologous chondrocyte implantation. The advent of particulated juvenile articular cartilage (PJAC) provides an alternative method for OLTs refractory to traditional treatments. This article describes the technique of PJAC transplantation for the treatment of osteochondral lesions of the talus. Level V, expert opinion.

Clinical, Radiographic, and Histological Outcomes After Cartilage Repair With Particulated Juvenile Articular Cartilage

Background: Biological repair of cartilage lesions remains a significant clinical challenge because of the lack of natural regeneration and limited treatment options. Hypothesis: Treatment of articular cartilage lesions in the knee with particulated juvenile articular cartilage (PJAC) will result in an improvement in patient symptoms of pain and function and magnetic resonance imaging (MRI) findings at 2 years compared with baseline. Study Design: Case series; Level of evidence, 4. Methods: Patients with symptomatic articular cartilage lesions on the femoral condyles or trochlear groove of the knee were identified for treatment with PJAC. There were 25 patients with a mean age of 37.0 ± 11.1 years and a mean lesion size of 2.7 ± 0.8 cm2. All patients were assessed preoperatively (baseline) with a knee examination and surveys including the International Knee Documentation Committee (IKDC) subjective knee form, 100-mm visual analog scale (VAS) for pain, and Knee injury and Osteoarthritis Outcome Score (KOOS). Patients were followed at predetermined time points postoperatively through 2 years. Also, MRI was performed at baseline and at 3, 6, 12, and 24 months. At 2 years, patients were given the option of undergoing voluntary diagnostic arthroscopic surgery with cartilage biopsy to assess the histological appearance of the cartilage repair including safranin O staining for proteoglycans and immunostaining for type I and II collagen. Results: Clinical outcomes demonstrated statistically significant increases at 2 years after surgery compared with baseline, with improvements seen as early as 3 months. Over the 24-month follow-up period, the IKDC score increased from a mean of 45.7 to 73.6, KOOS-pain score from 64.1 to 83.7, KOOS-symptoms score from 64.6 to 81.4, KOOS–activities of daily living score from 73.8 to 91.5, KOOS–sports and recreation score from 44.6 to 68.3, and KOOS–quality of life score from 31.8 to 59.9. The MRI results suggested that T2-weighted scores were returning to a level approximating that of normal articular cartilage by 2 years. Histologically, the repair tissue in biopsy samples from 8 patients was composed of a mixture of hyaline and fibrocartilage; immunopositivity for type II collagen was generally higher than for type I collagen, and there appeared to be excellent integration of the transplanted tissue with the surrounding native articular cartilage. Other than elective biopsies, there were no reoperations, although 1 graft delamination was reported at 24 months. Conclusion: This study demonstrates a rapid, safe, and effective treatment for cartilage defects. For the patient population investigated, the clinical outcomes of the PJAC technique showed a significant improvement over baseline, with histologically favorable repair tissue 2 years postoperatively.

Particulated Juvenile Articular Cartilage Implantation in the Knee: A 3-Year EPIC-µCT and Histological Examination.

Objective:The goal of this report is to describe the outcome of sequential particulated cartilage allograft and autologous osteochondral transfer treatments for an osteochondral lesion of the medial femoral condyle.Methods:A 44-year-old woman was treated with a particulated juvenile articular cartilage allograft (DeNovo NT) for a chondral lesion of the knee. As a result of continued pain, she had 2 further surgeries, including an autologous osteochondral transfer system procedure and finally a unicondylar knee arthroplasty. At the final procedure, the areas of the allograft and autograft tissue were biopsied for histological evaluation. The quality of the residual cartilage tissue was assessed first by equilibrium partitioning of an ionic contrast agent via micro–computed tomography (EPIC-µCT), and then by hematoxylin and eosin, Safranin O staining, and polarized light microscopy.Results:Despite showing good healing at 7 months postsurgery by MRI, at 28 months post DeNovo NT tissue implantation the excised cartilage tissue was heterogeneous, with some regions of hyaline-like cartilage and some regions of fibrocartilage. The later mosaicplasty may have helped maintain hyaline-like cartilage of the DeNovo NT tissue in its vicinity.Conclusion:This case report describes the cartilage repair tissue produced by DeNovo NT implantation and compares it with autologous osteochondral plug tissue.

Preliminary Results of a Novel Single-Stage Cartilage Restoration Technique: Particulated Juvenile Articular Cartilage Allograft for Chondral Defects of the Patella

To evaluate outcomes and magnetic resonance imaging (MRI) findings after use of particulated juvenile cartilage for the treatment of focal Outerbridge grade 4 articular cartilage defects of the patella. From 2007 to 2011, 16 patients (2 bilateral) underwent a novel single-stage articular cartilage restoration procedure using particulated juvenile articular cartilage allograft. We enrolled 15 knees (13 patients) in this study. The mean age at surgery was 26.4 ± 9.1 years, and the mean postoperative follow-up was 28.8 ± 10.2 months. A musculoskeletal radiologist evaluated each knee with postoperative MRI for the International Cartilage Repair Society cartilage repair assessment score, graft hypertrophy, bony changes around the graft, and percent fill of the defect. All patients also completed the Knee Injury and Osteoarthritis Outcome Score, International Knee Documentation Committee Subjective Knee Evaluation, and Kujala clinical outcome survey (scale, 0 to 100), as well as the Tegner activity scale and visual analog pain scale (scale, 0 to 10). The mean International Cartilage Repair Society cartilage repair assessment score on MRI was 8.0 ± 2.8, a nearly normal assessment. Of 15 knees, 11 (73%) were found to have normal or nearly normal cartilage repair. Three patients had mild graft hypertrophy whereas 2 had gross graft hypertrophy, 2 of whom required arthroscopic debridement because of symptoms. The mean fill of the defect at follow-up was 89% ± 19.6%, with 12 of 15 knees (80%) showing at least 90% defect coverage. The mean clinical outcome score at follow-up was 73.3 ± 17.6 for the International Knee Documentation Committee evaluation, and the mean scores for each subdomain of the Knee Injury and Osteoarthritis Outcome Score were as follows: 84.2 ± 14.2 for pain, 85.0 ± 12.3 for symptoms and stiffness, 88.9 ± 12.9 for activities of daily living, 62.0 ± 25.1 for sports and recreation, and 60.8 ± 28.6 for quality of life. The median score for the Kujala survey was 79 (range, 55 to 99). The median score on the Tegner activity scale was 5 (range, 3 to 9), and the mean score on the visual analog scale was 1.9 ± 1.4, indicating minimal pain. Preliminary results suggest that cartilage restoration using particulated juvenile articular cartilage allograft offers a viable option for patients with focal grade 4 articular cartilage defects of the patella.

2-Year Postoperative Evaluation of a Patient with a Symptomatic Full-Thickness Patellar Cartilage Defect Repaired with Particulated Juvenile Cartilage Tissue

This case report describes the early results of a 36-year-old man who underwent repair of a symptomatic full-thickness patellar cartilage defect with transplanted particulated juvenile articular cartilage. At 2 years postoperatively, the patient has experienced substantial clinical improvement in both pain and function when evaluated with both International Knee Documentation Committee subjective evaluation and Knee Injury and Osteoarthritis Outcome Score outcome measures. Two-year postoperative magnetic resonance imaging demonstrates fill of the defect with repair tissue and near complete resolution of preoperative subchondral bone edema. To the best of the authors' knowledge, this case report is the first to report clinical results of this new technique at 2 years postoperatively.