International Cartilage Repair Society Research Articles

Application of Alginate-Collagen Hydrogel and Its Related Mechanisms in the Repair of Rat Cartilage Injuries

This research investigated the application of alginate-collagen hydrogel (ACH) in rat cartilage injury (CI) repair and its related mechanisms through in vitro and in vivo experiments. Alginate solution and modified collagen solution were mixed to prepare the ACH. The obtained samples were characterized and their sustained release properties were determined. L929 mouse fibroblasts were assigned into a blank control group (BC group, untreated), a positive control group (PC group, treated with 6.4% phenol), a negative control group (NC group, treated with tissue culture polystyrene), and an ACH group (treated with ACH). Cell viability was assessed using the MTT assay. Meanwhile, the cytotoxicity of the ACH and its impact on cell proliferation and cell attachment capabilities were analyzed. Thirty 4-week-old specific pathogen-free (SPF) Sprague Dawley (SD) rats were randomly grouped into a chondrocyte group (5 rats, chondrocytes collected and cultured), a cPAGE group (5 rats, chondrocytes treated with ACH), a model group (10 rats, CI model), and a mPAGE group (10 rats, CI model treated with CAH). The influence of CAH on chondrocyte proliferation and the type II collagen (COLII) expression were assessed using the cell counting kit 8 (CCK-8) assay and immunofluorescence staining. Furthermore, the impacts of CAH on chondrocyte tissue and COL-II expression were analyzed using Safranin O-Fast Green (SOFG) staining, the International Cartilage Repair Society (ICRS) score, and COL-II tissue staining. Immunoblotting was utilized to detect the TNF-α, NF-κB, matrix metalloproteinase 13 (MMP-13), and COL-II proteins in cartilage tissue. The results showed that release rate (RR) of the constructed ACH reached over 85% within 72 hours and achieved degradation equilibrium within 5 days with a weight loss (WL) rate of over 60%. L929 fibroblasts culture results showed that the ACH posed no significant cytotoxicity, and cell attachment results were not obviously different from those on tissue culture plates (P >0.05). MTT assay results demonstrated that the ACH exerted no adverse effects on L929 cell proliferation and growth, indicating a good biocompatibility. CCK-8 and COL-II results indicated that chondrocyte proliferation in cPAGE group was much higher in contrast to that in chondrocyte group (P <0.05). Besides, the animal experiments unveiled that in comparison to the CI group, the mPAGE group had more chondrocytes, upregulated COL-II, and higher ICRS scores (P <0.05). MMP-13, NF-κB, and TNF-α were downregulated, and COL-II was upshifted in the mPAGE group, with remarkable differences (P <0.05). In conclusion, ACH exhibited excellent biocompatibility and low cytotoxicity, promoted cell proliferation and growth, facilitated chondrocyte proliferation in rat CI repair, offering a valuable research foundation for CI treatment.

The collagen-augmented chondrogenesis technique demonstrates superior cartilage repair compared to microfracture for cartilage defects of the knee joint, regardless of age.

This study investigated whether age affects clinical outcomes and cartilage repair quality in patients who underwent collagen-augmented chondrogenesis. The study included patients who underwent either the collagen-augmented chondrogenesis technique or microfracture for cartilage defects of the knee joint of International Cartilage Repair Society grade 3 or 4. Patients were categorised according to an age threshold of 50 years and the treatment method, whether collagen-augmented chondrogenesis technique or microfracture. Group 1 comprised 31 patients aged 50 years or older who received the collagen-augmented chondrogenesis technique, Group 2 consisted of 32 patients under the age of 50 years who received the collagen-augmented chondrogenesis technique and Group 3 included 243 patients aged 50 years or older who received microfracture. Clinical outcomes were assessed using the walking visual analogue scale (VAS) for pain and the Western Ontario McMaster University Osteoarthritis Index scale score (WOMAC) two years after surgery. For patients with magnetic resonance imaging results 1 year postoperatively (Group 1: 30 patients; Group 2: 31 patients; and Group 3: 31 patients), Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) assessment was used to evaluate repaired cartilage lesions. There were no significant differences in the VAS and WOMAC scores between the three groups 2 years after surgery (all n.s.). The MOCART score in patients who underwent MRI at 1 year postoperatively showed significant differences in the degree of defect repair, integration with the border zone, surface of the repaired tissue, adhesion and total score among the three groups (all p < 0.05). Post hoc analysis revealed no difference in the total MOCART scores between Groups 1 and 2. However, Groups 1 and 2 had significantly higher MOCART scores than Group 3 1 year after surgery (all p < 0.05). The collagen-augmented chondrogenesis technique group showed improved quality of cartilage repair compared to the microfracture group, regardless of patient age. Compared with simple microfracture treatment, there were no differences in clinical outcomes between the patient groups, related to age. Level Ⅲ.

Proposed Classification of Syndesmotic Soft Tissue Impingement and Its Association With Lateral Talar Cartilage Lesions.

Syndesmotic impingement syndrome has been described to explain persistent lateral or anterolateral ankle pain. This condition is thought to often result from a rotational ankle injury. This study aimed to identify the type of syndesmotic impingement tissue according to arthroscopic and histologic findings and to analyze its association with lateral talar cartilage lesions. This retrospective study included 107 ankles in 105 patients who underwent arthroscopic surgery for syndesmotic impingement syndrome from January 2017 to August 2019. Histologic findings of biopsied impingement tissue were obtained in 59 ankles (55.1%) and compared with gross findings on arthroscopy. Cartilage lesions were evaluated using the International Cartilage Repair Society grading system. Risk factors associated with lateral talar cartilage injury were evaluated using multivariate logistic regression analysis. Based on the histologic results, the most common pathology was fibrosis (24 ankles [22.4%]), followed by fatty degeneration (23 ankles [21.5%]), synovial hyperplasia (8 ankles [7.5%]), and inflammatory synovium (4 ankles [3.7%]). Interclass correlation coefficient was 0.841 (P = .001) between histologic results and arthroscopic findings. Patients with fibrotic impingement tissue had on average a significantly longer duration of symptoms (12 vs 48 months, P = .021). A lateral talar dome cartilage lesion was detected in 25 ankles (23.4%). Fibrotic impingement tissue was the only factor significantly associated with lateral talar dome lesion on multivariate logistic regression analysis (odds ratio 10.04; 95% CI 1.84-54.9; P = .008). Syndesmotic impingement with fibrotic tissue was often associated with cartilage lesions at the lateral talar dome. Patients with prolonged anterolateral or lateral ankle pain after a rotational ankle injury warrant careful assessment for possible syndesmotic impingement by fibrotic tissue and associated lateral talar cartilage injury.

Comparative efficacy of synthetic peptide, platelet-rich plasma, and hyaluronic acid alone or in combination in microfracture treatment of focal chondral defects

Aims: Although previous limited studies have evaluated the efficacy of adjuvants used alone or in combination to augment microfracture (MF) treatment for focal chondral defects, there are no studies comparing the outcomes of the synthetic peptide (SP) with other adjuvants such as platelet-rich plasma (PRP), hyaluronic acid (HA), or their combinations. This study aimed to evaluate whether the efficacy of MF treatment in focal chondral defects is influenced by the use of adjuvants either alone or in combination. Methods: Thirty-six rats were included in the study. Group 1 received MF alone, Group 2 received PRP after MF, Group 3 received HA after MF, Group 4 received a SP after MF, Group 5 received a SP plus PRP therapy after MF, and Group 6 received a SP plus HA therapy. The knees of the rats were assessed according to the International Cartilage Repair Society (ICRS) Cartilage Repair Assessment 1 (ICRS-1) and 2 (ICRS-2). Results: The median ICRS-1 and ICRS-2 scores in Group 1 were lower compared to the other groups, while these scores in Group 2 and Group 4 were similar and higher than the other groups. Also, these scores in Group 5 and Group 6 were similar and lower compared to Group 3 (Group 1: 1 vs. Group 2: 12 vs. Group 3: 9 vs. Group 4: 11 vs. Group 5: 7 vs. Group 6: 7, p &lt; 0.001 for ICRS-1 scores; Group 1: 0 vs. Group 2: 85 vs. Group 3: 70 vs. Group 4: 80 vs. Group 5: 45 vs. Group 6: 45, p &lt; 0.001 for ICRS-2 scores). Conclusion: In the MF treatment of focal chondral defects, SP, PRP, and HA injections have a beneficial adjuvant effect based on macroscopic and histopathological findings. However, the combination of these adjuvants is less beneficial than their individual usage.

A hypertrophic distal fascicle of the anterior tibiofibular ligament is associated with a high rate of osteochondral lesions of the talus.

The purpose of this retrospective review was to determine the prevalence of osteochondral lesions (OCLs) of the lateral talar dome in patients with anterior ankle impingement with an associated hypertrophic distal fascicle of the anterior tibio-fibular ligament. Retrospective chart review identified 40 patients who underwent anterior ankle arthroscopy for the management of anterior ankle impingement. Clinical outcomes assessed includedpre- and postoperative foot and ankle outcome score (FAOS), visual analogue scale (VAS), complications, failures, secondary surgical procedures, return-to-work data and return-to-sport data. Thirty-two patients with a mean follow-up time of 29.3 ± 10.4 months were included. The hypertrophic distal fascicle of the anterior tibio-fibular ligament was hypertrophic in 29 patients (90.6%), with a mean thickness of 2.5 ± 0.4 mm on MRI. There were 22 OCLs of the lateral talar dome (75.9%) with an associated hypertrophic distal fascicle of the anterior tibio-fibular ligament visualized during arthroscopy. The international cartilage repair society gradings of the lesions included3 (13.6%) grade I lesions, 15 (68.1%) grade II lesions, 3 (13.6%) grade III lesions, and 1 (4.6%) grade IV lesion. There was a statistically significant improvement in mean FAOS and VAS scores from preoperative to postoperative (p < 0.001). No cases of syndesmotic instability were observed following resection of hypertrophic distal fascicle of the anterior tibio-fibular ligament. This retrospective case series demonstrated that a hypertrophic distal fascicle of the anterior tibio-fibular ligament was associated with an OCL of the lateral talar dome identified during arthroscopic evaluation. In addition, preoperative MRI demonstrated poor sensitivity for the detection of these OCLs. Heightened awareness is warranted for potential lateral talar dome OCLs in patients presenting with anterolateral ankle impingement with a hypertrophic ATiFLdf identified on preoperative MRI in the absence of an associated OCLs. Level IV, Retrospective case series.

Higher Accuracy of Arthroscopy Compared to MRI in the Diagnosis of Chondral Lesions in Acute Ankle Fractures: A Prospective Study.

Even after successful surgery for acute ankle fractures, many patients continue having complaints. A possible explanation is the presence of concomitant chondral lesions. The aim of this study is to investigate the accuracy of MRI compared to that of arthroscopy in the assessment of chondral lesions in acute ankle fractures. In this prospective single-center study, patients presenting with acute ankle fractures over a period of three years were identified. A preoperative MRI was performed within a maximum of 10 days after trauma. During surgery, ankle arthroscopy was also performed. The International Cartilage Repair Society (ICRS) cartilage lesion classification was used to grade the detected chondral lesions. To localize the chondral lesions, the talar dome was divided into eight zones and the tibial/fibular articular surfaces into three zones. In total, 65 patients (28 females) with a mean age of 41.1 ± 15 years were included. In the MRI scans, 70 chondral lesions were detected (69.2% of patients) affecting mostly the tibial plafond (30%) and mostly graded as ICRS 3. The mean lesion area measured was 20.8 mm2. In the arthroscopy, 85 chondral lesions were detected (70.8% of patients) affecting mostly the medial surface of the talar dome (25.9%) and mostly graded ICRS 3. The mean lesion area measured was 43.4 mm2. The highest agreement between the two methods was observed in the size estimation of the chondral lesions. The present study shows the reduced accuracy of MRI when compared to arthroscopy in the assessment of traumatic chondral lesions in the setting of acute ankle fractures especially regarding lesion size. MRI remains an essential instrument in the evaluation of such lesions; however, surgeons should take this discrepancy into consideration, particularly the underestimation of chondral lesions' size in the preoperative planning of surgical treatment and operative technique.

A higher incidence of chondral injuries on the medial femoral condyle in concomitant ACL ruptures, no significant difference in treatment:A systematic review.

The associated damage to articular cartilage in anterior cruciate ligament (ACL) injured patients is a well-recognized phenomenon; however, there is a relative paucity in the literature regarding the different treatment techniques and outcomes. The purpose of this systematic review was to identify patients treated for acute ACL rupture and associated cartilage injury, with interest in the surgical management of these chondral injuries and any difference in patient-reported outcome measures (PROMs) differing techniques. A systematic review was performed looking for treatment or management of International Cartilage Repair Society grade 3 or 4 articular cartilage injury at the time of ACLreconstruction. Seventeen studies fit the criteria, a total of 892 patients were included, 64.6% were male with a mean age of 33.7and the average time to follow-up was 41.7 months. 68.2% of the lesions were on the medial femoral condyle (MFC) with a mean lesion size of 3.9 cm2. Six different operative methods of dealing with chondral lesions were identified, there was no significant difference in PROMs between the techniques, although there was a significant difference between the preoperative and postoperative outcome measures. The systematic review found that chondral defects on the MFC are more common in concomitant ACL injuries, despite the pattern of bone bruising being more common on the lateral femoral condyle as reported in the literature. It also found no significant difference in the PROMs between the six different techniques identified for the concomitant management of ACL reconstruction and chondral defects. Level II.

Comparative Efficacy of Endogenous Stem Cells Recruiting Hydrogels and Stem Cell-loaded Hydrogels in Knee Cartilage Regeneration: A Meta- analysis.

Cartilage defects remain a challenge in diseases such as osteoarthritis (OA) and fractures. Scientists have explored the use of hydrogels in conjunction with stem cell technology as a tissue engineering method to treat cartilage defects in joints. In recent years, research into hydrogels containing stem cell technology for cartilage repair has mainly focused on two categories: stem cell-loaded hydrogels and endogenous stem cell recruiting hydrogels. The latter, utilizing cell-free products, represents a novel concept with several advantages, including easier dose standardization, wider sources, and simpler storage. This meta-analysis aims to assess and compare the therapeutic effects of endogenous stem cell recruiting hydrogels and stem cell-loaded hydrogels in promoting articular cartilage regeneration in animal models, with the goal of exploring endogenous stem cell recruiting hydrogels as a promising replacement therapy for knee cartilage regeneration in preclinical animal studies. We systematically searched PubMed, Web of Science, Cochrane Library, and Embase until January 2023 using key words related to stem cells, cartilage regeneration and hydrogel. A random-effects meta-analysis was performed to evaluate the therapeutic effect on newborn cartilage formation. Stratified analyses were also carried out by independently classifying trials according to similar characteristics. The level of evidence was determined using the GRADE method. Twenty-eight studies satisfied the inclusion criteria. Comprehensive analyses revealed that the use of endogenous stem cell recruiting hydrogels significantly promoted the formation of new cartilage in the knee joint, as evidenced by the histological score (3.77, 95% CI 2.40, 5.15; p < 0.0001) and the International Cartilage Repair Society (ICRS) macroscopic score (3.00, 95% CI 1.83, 4.18; p = 0.04), compared with the control group. The stem cell-loaded hydrogels also increased cartilage regeneration in the knee with the histological score (3.13, 95% CI 2.22, 4.04; p = 0.02) and the ICRS macroscopic score (2.49, 95% CI 1.16, 3.82; p = 0.03) in comparison to the control. Significant heterogeneity between studies was observed, and further stratified and sensitivity analyses identified the transplant site and modelling method as the sources of heterogeneity. The current study indicates that both endogenous stem cell recruiting hydrogels and stem cell loaded hydrogels can effectively promote knee joint cartilage regeneration in animal trials.

The Number of Patellar Dislocation Events Is Associated With Increased Chondral Damage of the Trochlea

Background: Patellofemoral instability is associated with chondral injuries to the patella, trochlea, and lateral femoral condyle. Although studies have demonstrated an association between patellar dislocations and chondral injuries, the influence of the number of dislocations on chondrosis is not established. Purpose: To elucidate the precise association between the number of patellar dislocation events and the severity of chondral injuries in a multicenter cohort study at the time of patellar stabilization procedures. Study Design: Cross-sectional study; Level of evidence, 2. Methods: A prospective multicenter cohort study (JUPITER [Justifying Patellar Instability Treatment by Early Results]) database was queried for cases of primary patellofemoral instability procedures from December 2016 to September 2022. Cartilage lesions were classified using the International Cartilage Repair Society (ICRS) classification system during an arthroscopic or open evaluation (direct visualization), with grades 2 to 4 considered abnormal. The number of dislocations was categorized as 1, 2-5, and >5. Categorical variables were compared with the chi-square test, and binary logistic regression was performed to identify predictors of the presence of chondral lesions. Results: A total of 938 knees (mean age, 16.2 ± 3.8 years; 61.4% female) were included, with 580 (61.8%) demonstrating a chondral injury. The most affected region was the patella (n = 498 [53.1%]), followed by the lateral femoral condyle (n = 117 [12.5%]) and trochlea (n = 109 [11.6%]). There were no differences in the presence (P = .17) or grade (P = .63) of patellar lesions by the number of dislocations. Patients with >5 dislocations more frequently had trochlear chondral lesions (19.8%) compared with those with fewer dislocations (1, 7.6%; 2-5, 11.0%; P < .001). More dislocations were also associated with a higher proportion of ICRS grade 2 to 4 trochlear lesions (>5, 15.3%; 2-5, 10.0%; 1, 6.9%; P = .015). Combined patellar and trochlear lesions were also more common in those with >5 dislocations (P = .001). In multivariable regression, >5 dislocations was the only variable predictive of a trochlear lesion (odds ratio, 3.03 [95% CI, 1.65-5.58]; P < .001). Conclusion: This large prospective cohort study demonstrated that recurrent patellar dislocations can lead to more severe chondral damage in specific locations in the knee. More than 5 dislocations was associated with a >3-fold increase in the incidence and severity of trochlear chondral injuries. There were no differences in the presence or grade of patellar lesions by the number of dislocations. These findings should caution surgeons regarding prolonged nonoperative treatment.

Comparison of Patient-Reported Outcomes for Immediate Unrestricted Weightbearing Versus Restricted Rehabilitation Protocols After Osteochondral Allograft Transplantation to the Distal Femur.

There is no standardized rehabilitation protocol after osteochondral allograft (OCA) transplantation surgery to the distal femur. The spectrum of recommendations includes restrictions to toe-touch weightbearing (TTWB) for 6 weeks and immediate weightbearing as tolerated (WBAT). The purpose of this study was to compare outcomes for immediate unrestricted WBAT to restricted TTWB after OCA transplantation to the distal femur. It was hypothesized that the immediate WBAT protocol would be noninferior to delayed, restricted TTWB. Retrospective cohort study. A total of 74 patients who underwent press-fit, dowel technique OCA transplantation to the femoral condyle(s) for contained (International Cartilage Repair Society grade 3-4) lesions were identified in the Metrics of Osteochondral Allograft multicenter database: 36 patients (18 women/18 men) who were prescribed TTWB were allocated to the control cohort and 38 patients (21 women/17 men) who were prescribed WBAT were allocated to the test cohort. Baseline characteristics were similar except for larger grafts in test patients (3.4 vs 2.7 cm2; P = .004) and higher body mass index (BMI) in control patients (27.8 vs 24.9 kg/m2; P = .01). Failure rates, final patient-reported outcome (PRO) scores, and PRO score changes from baseline were compared between the cohorts. Multiple regression was used to control for potential confounders and investigate noninferiority using minimal clinically important differences (MCIDs). The mean follow-up was 2 years (range, 1-5 years) in both cohorts. Both cohorts showed significant improvement in all PRO scores, with no significant between-group differences in failure rates, final PRO scores, or PRO changes from baseline. There were 3 cases of failure in each cohort (control cohort: allograft revision [n = 2], debridement [n = 1]; test cohort: chondroplasty [n = 2], conversion to total knee arthroplasty [n = 1]). Regression analysis showed that adjusted differences in final PRO scores based on weightbearing protocol were minor and less than MCIDs when controlling for age, sex, graft size, BMI, and allograft location. Analysis of the MCIDs with respect to the lower bounds of the confidence intervals indicated that WBAT was noninferior to TTWB with a reasonable degree of confidence (range, 84.1%-99.9% confidence). Results indicated that immediate unrestricted WBAT after OCA transplantation to the distal femur was equally safe and effective compared to restricted TTWB.

Save the subchondral bone plate: Debridement versus bone marrow stimulation in acetabular cartilage defects over 60 months of follow-up.

Bone marrow stimulation is a common treatment for full-thickness cartilage defects in the hip joint. However, common procedures may result in poor fibrous repair tissue and changes to the subchondral anatomy. This study investigated the clinical outcome of a cohort of International Cartilage Repair Society (ICRS) grades 3 and 4 cartilage defects treated with bone marrow stimulation compared to those who received simple debridement/chondroplasty. In this retrospective registry study, 236 patients with uni-focal acetabular chondral lesions of the hip up to 400 mm² (mean 177.4 ± 113.4 mm²) and of ICRS grade ≥3 with follow-up of at least 12 months (mean 33.2 ± 15.3 months) were included. Eighty-one patients underwent bone marrow stimulation (microfracture: n = 44, abrasion: n = 37) besides treatment of the underlying pathology, 155 patients underwent defect debridement/chondroplasty. The patient-reported outcome was measured using the International Hip Outcome Tool 33 (iHOT33) score and the Visual Analogue Scale (VAS) for pain. iHOT33 and VAS both improved highly statistically significantly (p < 0.001) in the debridement group after 6, 12, 24, 36 and 60 months compared to the preoperative scores, whereas iHOT33 and VAS after microfracture or abrasion did not show statistically significant changes over time. Twenty-four and sixty months postsurgery the debridement group revealed significant higher scores in the iHOT33 compared to the bone marrow stimulation groups. Patients with chondral lesions of the hip ≤400 mm2 sustainably benefit from arthroscopic debridement under preservation of the subchondral bone plate in terms of functional outcome and pain in contrast to patients treated with bone marrow stimulation. These findings discourage the currently recommended use of microfracture in the hip joint. Level III.

The clinical application value of 3.0T magnetic resonance T2 mapping imaging in evaluating the degree of acetabular cartilage degeneration in joint replacement surgery running title: MRI and acetabular cartilage degeneration

BackgroundTo explore and compare the values of 3.0T magnetic resonance imaging (MRI) T2 mapping in evaluating the degree of acetabular cartilage degeneration in hip replacement surgery.MethodsA total of 26 elderly patients with femoral neck fractures who were scanned in 3.0T MRI T2 mapping quantification technique were included. Basing on MRI images, the degree of acetabular cartilage degeneration was classified into Grade 0, 1, 2, 3 and 4, according to the International Cartilage Repair Society (ICRS) scores. In addition, 8 healthy volunteers were included for control group.ResultsBy comparison with health population, T2 relaxation values in the anterior, superior, and posterior regions of acetabular cartilage in patients with femoral neck fracture were obviously increased (P < 0.001). Among the patients with femoral neck fractures, there were 16 hip joint with Grade 1–2 (mild degeneration subgroup) and 10 hip joints with Grade 3–4 (severe degeneration subgroup), accounting for 61.54% and 38.46%, respectively. Additionally, T2 relaxation values in the anterior and superior bands of articular cartilage were positively related to the MRI-based grading (P < 0.05); while there was no significant difference of T2 relaxation values in the posterior areas of articular cartilage between severe degeneration subgroup and mild degeneration subgroup (P > 0.05). Importantly, acetabular cartilage degeneration can be detected through signal changes of T2 mapping pseudo-color images.Conclusion3.0T MRI T2 mapping technology can be used to determine the degree of acetabular cartilage degeneration, which can effectively monitor the disease course.

Longitudinal measurement of serum cartilage oligomeric matrix protein can detect the progression of cartilage degeneration in anterior cruciate ligament reconstruction patients

Background/objectiveCartilage oligomeric matrix protein (COMP) has utility as a diagnostic marker for osteoarthritis (OA). Our previous study revealed that the serum COMP level can be used to detect early cartilage change in non-OA patients with anterior cruciate ligament (ACL)-deficiency. However, there are still no studies on detecting the progression of cartilage degeneration in early OA. The aim of present study was to investigate whether serum COMP can detect the progression of cartilage degeneration after ACL reconstruction in non-OA patients. MethodsPatients without cartilage degeneration of early OA at ACL reconstruction and whose serum COMP levels could be measured were included in the study. Cartilage degeneration of early OA were defined as International Cartilage Repair Society (ICRS) grade 1 to 4 in more than 2 compartments or ICRS grade 2 to 4 in 1 compartment. The patients were divided into two groups: those who had cartilage degeneration of early OA at second-look arthroscopy (cartilage degeneration progression group) and those who did not (non-progression group), and the serum COMP values between the two groups were compared. ResultsThirty-one patients were included. There were 8 cases (25.8 %) in progression group and 23 cases (74.2 %) in non-progression group. There were significant differences between the two groups regarding age and change in serum COMP level. In terms of the rate of change in COMP, an increase of more than 1.24-fold was the cut-off value for detecting the progression of cartilage degeneration. ConclusionsIn this study, the increase in serum COMP levels was significantly greater in progressed cartilage degeneration group than non-progression group after ACL reconstruction. Longitudinal serum COMP measurement could detect the progression of cartilage degeneration. Level of evidenceLevel Ⅲ, retrospective comparative study.

Paper 35: Number of Patellar Dislocation Events are Associated with Increased Chondral Damage of the Trochlea: data from the JUPITER group

Objectives: Patellofemoral instability (PFI) is frequently associated with chondral injuries to the patella and trochlea. Though several radiographic and intra-operative studies have demonstrated a link between patellar dislocation and chondral injury, the influence of the number of patellar dislocation events on the presence of chondral wear and severity is not established. This study aimed to understand the association between the number of patellar instability events and chondral damage observed directly in a large patient population undergoing patellar stabilization procedures. Methods: This was a retrospective review of the prospective multi-center Justifying Patellar Instability Treatment by Results (JUPITER) cohort. All patients undergoing primary surgical procedures to address PFI from 12/2016 to 9/2022 with a recorded number of patellar dislocations and detailed intra-operative assessment of the articular cartilage were included. Cartilage lesions were classified using the International Cartilage Repair Society (ICRS) classification, where ICRS grades 2 to 4 are defined as abnormal or severely abnormal. The number of dislocation events was grouped into 1-2, 3-5, and &gt;5 dislocations. Continuous and categorical variables were compared using independent t-tests and chi-squared tests, respectively with multivariable regressions used to control for demographic characteristics potentially influencing cartilage wear. A significance threshold of p&lt;0.05 was used. Results: A total of 938 patients at mean age 16.2 ± 3.8 years (range 5.1-35.0 years, 61.4% female patients) undergoing PFI procedures were included. Of these, 580 (61.8%) demonstrated a chondral injury. The most commonly affected region was the patella (n = 498, 53.1%) followed by the femoral condyles (n = 148, 15.8%), and trochlea (n = 109, 11.6%), with 83 (8.8%) patients having lesions located on both the patella and trochlea (Table 1). MPFL reconstruction was performed in 861 (91.8%) cases (Table 2), with other commonly performed procedures including patellofemoral chondroplasty (n = 388, 41.4%) and lateral retinacular lengthening or release (n = 255, 27.2%). Patients with fewer dislocations more frequently underwent fixation of an osteochondral fragment (1-2: 19.5%, 3-5: 7.6%, &gt;5: 1.7%, p&lt;0.001). There were no differences in the presence (p=0.209) or grade (p=0.716) of patellar chondral lesions based on dislocation number (Table 3). Patients with &gt;5 patellar dislocations more frequently had a trochlear chondral lesion (19.8%) compared to the groups with fewer dislocations (1-2: 8.4%, 3-5: 13.0%, p&lt;0.001). A greater number of dislocations was also associated with a higher proportion of abnormal (ICRS grades 2-4) trochlear lesions (&gt;5: 15.3%, 3-5: 11.7%, 1-2: 7.6%, p=0.009), and the mean trochlear ICRS grade was significantly greater for the highest dislocator group (&gt;5, mean 0.45 ± 0.99, p=0.023) compared to those with fewer dislocations (1-2: mean 0.24 ± 0.84, 3-5: mean 0.34 ± 0.93). Combined patellar and trochlear lesions were also higher in the most frequent dislocation group (&gt;5 dislocations: 15.8%, 3-5: 9.9%, 1-2: 6.1%, p&lt;0.001). In multivariable regression accounting for age, sex, BMI, and dislocation count, a dislocation count &gt;5 was the only variable significantly predictive of the presence of a trochlear chondral lesion (OR 2.16, 95% CI 1.36-3.43, p=0.001). Both age in years (OR 1.11, 95% CI 1.06-1.16, p&lt;0.001) and BMI (OR 1.05, 95% CI 1.02-1.07, p&lt;0.001) were predictive of a patellar lesion, while both age in years (OR 1.07, 95% CI 1.01-1.13, p=0.017) and dislocation count &gt;5 (OR 2.25, 95% CI 1.35-3.75, p=0.002) were predictive of the presence of both a patellar and trochlear lesion. Conclusions: This study demonstrates that an increased number of patellofemoral dislocation events is associated with more frequent trochlear and combined patellar/trochlear chondral damage with higher injury severity. Specifically, a dislocation count &gt;5 is associated with a greater than 2-fold increase in the number of trochlear chondral injuries, which are of higher severity potentially requiring surgical management. Conversely, patients with fewer dislocation events were more likely to undergo osteochondral fracture fixation, which may have driven earlier operative intervention in this group. This is the first, large prospective study to demonstrate that multiple patellar dislocations can result in increased and more severe chondral damage.

Preoperative Medial Meniscus Extrusion on Magnetic Resonance Imaging Is Associated With a Tendency Toward Varus Shifting of Open-Wedge High Tibial Osteotomy: A Minimum 5-Year Follow-Up Study

PurposeTo investigate serial changes in postoperative alignment over 5 years after open-wedge high tibial osteotomy (OWHTO) and to identify risk factors associated with alterations in the postoperative weight-bearing line WBL ratio. MethodsPatients who underwent OWHTO during 2011–2017 were retrospectively reviewed. Inclusion criteria were (1) follow-up duration ≥5 years and (2) serial postoperative long-standing hip-to-ankle radiographs to evaluate alignment alterations. The WBL ratio was measured preoperatively and at 3 months, 6 months, 1 year, and 5 years postoperatively to evaluate serial changes. Alterations in the WBL ratio were analyzed using a linear mixed model, considering potential risk factors including International Cartilage Repair Society (ICRS) grades of each compartment, and medial meniscus extrusion (≥3 mm). Clinical outcomes were assessed using the Knee Society (KS) objective and functional scores, and the correlations between clinical outcomes and alignment alteration were examined. ResultsA total of 78 knees were investigated. During the study period, the overall WBL ratio decreased by 5.5 ± 7.2%, signifying varus shifting, from 58.6 ± 11.5% at 3 months post-surgery to 51.5 ± 12.7% at 5 years post-surgery. Based on univariate regression analyses, ICRS grade of the medial compartment and medial meniscus extrusion were included in a linear mixed model regarding alignment alteration. The model identified medial meniscus extrusion as a significant risk factor after adjusting for time (p <0.001). Medial meniscus extrusion also had a significant interaction with time (p <0.001), indicating greater alignment alteration in cases of medial meniscus extrusion. The extrusion was noted in 68 out of 78 knees. ConclusionIn the midterm following OWHTO, the overall alignment had a tendency toward varus shifting. A linear mixed model found that preoperative medial meniscus extrusion on magnetic resonance imaging is associated with the tendency.

Poster 328: Effect of Knee Aspiration prior to ACL Reconstruction Surgery on Subsequent Surgery: A Randomized Clinical Trial

Objectives: The traumatic effusion associated with an acute anterior cruciate ligament (ACL) rupture contains pro-inflammatory cytokines, chemokines and matrix degrading enzymes. Aspiration of the effusion may help reduce the burden of joint inflammation. However, the short and mid-term implications of routine aspiration have not been well documented. The primary objective of this prospective, randomized control trial is to determine whether routine pre-operative aspiration upon presentation to the orthopaedic clinic impacts (a) all-cause re-operation rate in patients undergoing ACL reconstruction (ACLr) and, more specifically, (b) rate of surgical debridement for postoperative arthrofibrosis, a common clinical sequela of ACLr. Methods: Eligible patients presented to a single, academic sports surgeon with an acute ACL rupture and were clinically indicated for ACLr. Both sexes were included in this study. Exclusion criteria included pre-existing osteoarthritis (Kellgren-Lawrence grade 3 or greater), focal chondral injury (International Cartilage Repair Society grade 3 or higher), concurrent ipsilateral extra-articular injury, history of contralateral knee injury, or age greater than 62 years. Patients were randomized to either routine preoperative care or in-office aspiration of their traumatic effusion upon initial presentation. Patients underwent routine diagnostic arthroscopy at the time of ACLr to evaluate for concurrent chondral or meniscal pathology. Patients underwent standard postoperative rehabilitation and follow-up care. Results: Eighty-seven patients were enrolled in this study, with 46 (53%) patients randomized to and undergoing preoperative aspiration (Table 1). At a mean follow-up of 2.56 years, 14 patients (16%) underwent re-operation for any reason and 10 (11.5%) patients underwent debridement of arthrofibrosis (Table 2). Preoperative aspiration was not significantly associated with a decreased rate of arthrofibrosis (Figure 1) or re-operation (Figure 2). However, it was significantly associated with a longer time to debridement for arthrofibrosis (125 days vs 457 days, p = 0.0029). Conclusions: Preoperative aspiration does not modify rates of subsequent surgery following ACLr. In patients who develop arthrofibrosis after ACLr, preoperative aspiration is associated with a delay in the development of arthrofibrosis. This could be due to a decrease in burden of intraarticular inflammation after aspiration. Further study is needed to assess why aspiration delays the onset of arthrofibrosis and whether aspiration impacts long-term outcomes such as the development of post-traumatic OA.

Chondral regeneration in femoroacetabular lesions is favoured using peripheral blood stem cells with hyaluronan-based scaffold and micro-drilling: A prospective cohort study.

To determine whether intra-articular injections of peripheral blood stem cells (PBSC) with hyaluronan (HA)-based scaffold improve articular cartilage regeneration in chondral injuries caused by mixed-femoroacetabular impingement syndrome (FAIS) over a period longer than 24 months post-hip arthroscopy. In this prospective cohort study, patients with mixed-FAIS and chondral injury ≥ IIIB according to the International Cartilage Regeneration and Joint Preservation Society grade or III/IV of Konan/Haddad classification underwent intra-articular injection of PBSC with an HA-based scaffold and micro-drillings during hip arthroscopy. The degree of chondral repair was measured at baseline and 5 years using the International Cartilage Repair Society morphologic score system (MSS) as the primary outcome. Pain was measured at baseline and 5 years using the Visual Analogue Scale for Pain (VAS Pain), and hip functionality was measured at baseline (presurgery), 6 months, 1 year, and 5 years using the Hip Outcome Score (HOS). The largest diameter of injury, median follow-up, side effects, complications, and improvements were described. T-test, ANOVA with multiple comparisons, and statistical power were estimated. From initially 34 cases, 25 patients were enrolled. The median follow-up was 5.1 ± 0.3 years. One patient (4%) reported a few side effects with filgrastim administration. No infection, tumours, or synovitis was reported. The largest diameters in zones two, three, and four were 12.4 ± 3.1 mm (n = 8), 13.5 ± 2.8 mm (n = 14), and 11.4 ± 1.9 mm (n = 3), respectively. Ninety-two percent (23/25) of patients improved their outcomes. The MSS and HOS increased from 3.8 ± 1.1 to 9.6 ± 1.5 pts (p < 0.001) and from 65.5 ± 13.0 to 93.9 ± 2.4 pts (p < 0.001), respectively. The VAS-Pain decreased from 5.3 ± 0.7 to 1.3 ± 0.6 mm (p < 0.001). The obtained a posteriori power-size was 0.99. The intervention suggests a favourable impact on articular cartilage regeneration and clinical outcomes for hip chondral lesions in mixed-FAIS injuries after a median follow-up of 5.1 ± 0.3 years. Level IV.

Medial malleolar osteotomy in the treatment of osteochondral lesions of the Talus – incidence and impact on functional outcome: a retrospective analysis based on data from the German Cartilage Register (KnorpelRegister DGOU)

BackgroundThere has long been discussion regarding the impact of medial malleolar osteotomies (MMO) as an adjunctive treatment for osteochondral lesions of the talus (OCLT). MMO may improve the visibility and accessibility of the talus, but they also pose a risk of periprocedural morbidity. There is a lack of research about the prevalence and consequences of MMO in the surgical treatment of OCLT.MethodsThis study retrospectively evaluated data from the German Cartilage Register (KnorpelRegister DGOU) from its implementation in 2015 to December 2020. The impact of MMO on patient-reported outcome measures (PROMs) was investigated. Wherever possible, subgroups were built and matched using a propensity score which matched a group undergoing OCLT without MMO. Matching included age, sex, weight, localization of the OCLT, the international cartilage repair society (ICRS) grading, surgical procedure and preoperative symptoms using the Foot and Ankle Ability Measure (FAAM) and the Activities of Daily Living Subscale (ADL).ResultsThe prevalence of MMO in the operative treatment of OCLT was 15.9%. Most of the osteotomies were performed in OCL of the medial talar dome (76.8%) and in more serious lesions with an ICRS grade of III (29.1%) and IV (61.4%). More than half of the osteotomies (55.6%) were performed during revision surgery. A matched pair analysis of n = 44 patients who underwent AMIC® via arthrotomy and MMO vs. arthrotomy alone showed no significant differences in patient-reported outcome measures (PROMs, i.e. FAAM-ADL, and FAOS) at 6,12 and 24 months.ConclusionsMMO are mostly used in the treatment of severe (≥ ICRS grade 3) OCL of the medial talar dome and in revision surgery. Functional and patient-reported outcome measures are not significantly affected by MMO compared to arthrotomy alone.Trial registrationThe German Cartilage Register (KnorpelRegister DGOU) was initially registered at the German Clinical Trials Register (https://www.drks.de, register number DRKS00005617, Date of registration 03.01.2014) and was later expanded by the ankle module.

Comparative study on clinical outcomes in autologous chondrocyte implantation using three-dimensional cultured JACC® with collagen versus periosteum coverings

This study investigates the efficacy of a collagen membrane as a substitute for autologous periosteum in atelocollagen-assisted autologous chondrocyte implantation (ACI) using J-TEC autologous cultured cartilage (JACC®). Sixty-nine patients with knee joint chondral defects underwent ACI using JACC®—34 with periosteum-covered ACI (P-ACIs) and 35 with collagen-covered ACI (C-ACIs). Clinical outcomes were compared through patient-reported measures, International Cartilage Repair Society (ICRS) Cartilage Repair Assessment (CRA) scores at second-look arthroscopy one year postoperatively, and adverse event incidence. Postoperative subjective scores significantly improved up to two years, with no significant differences between P-ACI and C-ACI groups. However, C-ACI exhibited a lower adverse event rate (p = 0.034) and significantly higher ICRS CRA scores (p = 0.0001). Notably, C-ACI outperformed P-ACI in both femoral condyle and trochlea assessments (p = 0.0157 and 0.0005, respectively). While clinical outcomes were comparable, the use of a collagen membrane demonstrated superiority in ICRS CRA during second-look arthroscopy and adverse event occurrence.

Femoral trochlear groove cartilage damage after open-wedge high tibial osteotomy is associated with the change in patellar height relative to the femoral condyle

BackgroundMedial open-wedge high tibial osteotomy (OWHTO) is performed for isolated medial compartment osteoarthritis or osteonecrosis of the knee and correction of varus deformity of the full lower extremity. OWHTO may induce sagittal parameter changes, including these in the tibial posterior slope (TPS), patellar height (PH), and patellofemoral joint problems. This study aimed to identify radiographic parameters associated with patellofemoral cartilage damage after OWHTO. HypothesisThe patellofemoral joint cartilage worsens after OWHTO and is adversely affected by PH changes. Patients and methodsTwenty patients (25 knees) who underwent primary OWHTO and subsequent implant removal surgery, including second-look arthroscopy for evaluation of the patellofemoral cartilage condition were enrolled. The patients were received 12 to 35 months of postoperative follow-up, and categorized into two groups according to whether patellofemoral cartilage damage worsened. TPS and PH parameters, including the Insall–Salvati, Blackburne–Peel, Caton–Deschamps, and modified Blumensaat (MBI) indices, were measured on lateral knee radiographs. The hip-knee-ankle and medial proximal tibial angles were measured using an anteroposterior radiograph of the full lower extremity. The extent of change from preoperative to postoperative (Δ) was calculated for all indices. ResultsEleven knees (44%) had worsening cartilage conditions in the femoral trochlear groove, with>1-degree of deterioration in the International Cartilage Repair Society grade. The radiographic measure for predicting patellofemoral cartilage deterioration was ΔMBI (95% confidence interval [CI]: 3.53×10–14–0.812, p=0.047). PF cartilage damage tended to progress in ΔMBI<–0.145. The postoperative TPS and HKAA in patients with deterioration in patellofemoral cartilage damage was greater than that in patients without deterioration in patellofemoral cartilage damage (p=0.037 and 0.038, respectively). DiscussionThe patellofemoral cartilage damage tends to progress after OWHTO. ΔMBI is a factor for predicting worsening patellofemoral cartilage condition. However, attention should be paid to the excessive posterior slope as high TPS and valgus alignment as valgus HKAA because intraoperative control of MBI is impossible. Level of evidenceIV, retrospective study.