Prevalence of chondral defects in athletes' knees: a systematic review

Kinesiophobia and Pain Catastrophizing Leads to Decreased Return to Sport Following Autologous Chondrocyte Implantation but Does Not Affect Return to Work

OBJECTIVE

To evaluate the effect of fear of reinjury on return to sport (RTS), return to work (RTW), and clinical outcomes following autologous chondrocyte implantation (ACI).

DESIGN

A retrospective review of patients who underwent ACI with a minimum of 2 years in clinical follow-up was conducted. Patient-reported outcomes collected included the Visual Analog Scale (VAS) and Knee Injury and Osteoarthritis Outcome Score (KOOS). Kinesiophobia and pain catastrophizing was assessed using the Tampa Scale of Kinesiophobia-11 (TSK-11) and Pain Catastrophizing Scale (PCS), respectively. Patients were surveyed on their RTS and RTW status.

RESULTS

Fifty-seven patients (50.9% female) were included in our analysis. Twenty-two (38.6%) patients did not RTS. Of the 35 patients (61.4%) who returned, nearly half (48.6%) returned at a lower level of play. TSK-11 (P = 0.003), PCS (P = 0.001), and VAS pain scores (P < 0.001) were significantly greater in patients that did not RTS than in those who returned. All KOOS subscores analyzed were significantly lower (P < 0.001) in patients that did not RTS than in those who returned at the same level or higher. Of the 44 (77.2%) patients previously employed, 97.7% returned to work. Increasing TSK-11 scores were associated with lower odds of returning to sport (P = 0.003).

CONCLUSION

Fear of reinjury decreases the likelihood that patients will return to sport after ACI. Patients that do not return to sport report significantly greater levels of fear of reinjury and pain catastrophizing and lower clinical knee outcomes. Nearly all patients were able to return to work after surgery.

LEVEL OF EVIDENCE

IV case series.

Epigenetic Priming Enhances Chondrogenic Potential of Expanded Chondrocytes

Expansion of chondrocytes presents a major obstacle in the cartilage regeneration procedure, such as matrix-induced autologous chondrocyte implantation. Dedifferentiation of chondrocytes during the expansion process leads to the emergence of a fibrotic (chondrofibrotic) phenotype that decreases the chondrogenic potential of the implanted cells. We aim to (1) determine the extent that chromatin architecture of H3K27me3 and H3K9me3 remodels during dedifferentiation and persists after the transfer to a three-dimensional (3D) culture; and (2) to prevent this persistent remodeling to enhance the chondrogenic potential of expanded bovine chondrocytes, used as a model system. Chromatin architecture remodeling of H3K27me3 and H3K9me3 was observed at 0 population doublings, 8 population doublings, and 16 population doublings (PD16) in a two-dimensional (2D) culture and after encapsulation of the expanded chondrocytes in a 3D hydrogel culture. Chondrocytes were treated with inhibitors of epigenetic modifiers (epigenetic priming) for PD16 and then encapsulated in 3D hydrogels. Chromatin architecture of chondrocytes and gene expression were evaluated before and after encapsulation. We observed a change in chromatin architecture of epigenetic modifications H3K27me3 and H3K9me3 during chondrocyte dedifferentiation. Although inhibiting enzymes that modify H3K27me3 and H3K9me3 did not alter the dedifferentiation process in 2D culture, applying these treatments during the 2D expansion did increase the expression of select chondrogenic genes and protein deposition of type II collagen when transferred to a 3D environment. Overall, we found that epigenetic priming of expanded bovine chondrocytes alters the cell fate when chondrocytes are later encapsulated into a 3D environment, providing a potential method to enhance the success of cartilage regeneration procedures.

Development of a patient specific cartilage graft using magnetic resonance imaging and 3D printing

OBJECTIVES

The goal of this project was to develop and validate a patient-specific, anatomically correct graft for cartilage restoration using magnetic resonance imaging (MRI) data and 3-dimensional (3D) printing technology. The specific aim was to test the accuracy of a novel method for 3D printing and implanting individualized, anatomically shaped bio-scaffolds to treat cartilage defects in a human cadaveric model. We hypothesized that an individualized, anatomic 3D-printed scaffold designed from MRI data would provide a more optimal fill for a large cartilage defect compared to a generic flat scaffold.

METHODS

Four focal cartilage defects (FCDs) were created in paired human cadaver knees, age <40 years, in the weight-bearing surfaces of the medial femoral condyle (MFC), lateral femoral condyle (LFC), patella, and trochlea of each knee. MRIs were obtained, anatomic grafts were designed and 3D printed for the left knee as an experimental group, and generic flat grafts for the right knee as a control group. Grafts were implanted into corresponding defects and fixed using tissue adhesive. Repeat post-implant MRIs were obtained. Graft step-off was measured as the distance in mm between the surface of the graft and the native cartilage surface in a direction perpendicular to the subchondral bone. Graft contour was measured as the gap between the undersurface of the graft and the subchondral bone in a direction perpendicular to the joint surface.

RESULTS

Graft step-off was statistically significantly better for the anatomic grafts compared to the generic grafts in the MFC (0.0 ​± ​0.2 ​mm vs. 0.7 ​± ​0.5 ​mm, p ​< ​0.001), LFC (0.1 ​± ​0.3 ​mm vs. 1.0 ​± ​0.2 ​mm, p ​< ​0.001), patella (-0.2 ​± ​0.3 ​mm vs. -1.2 ​± ​0.4 ​mm, p ​< ​0.001), and trochlea (-0.4 ​± ​0.3 vs. 0.4 ​± ​0.7, p ​= ​0.003). Graft contour was statistically significantly better for the anatomic grafts in the LFC (0.0 ​± ​0.0 ​mm vs. 0.2 ​± ​0.4 ​mm, p ​= ​0.022) and trochlea (0.0 ​± ​0.0 ​mm vs. 1.4 ​± ​0.7 ​mm, p ​< ​0.001). The anatomic grafts had an observed maximum step-off of -0.9 ​mm and a maximum contour mismatch of 0.8 ​mm.

CONCLUSION

This study validates a process designed to fabricate anatomically accurate cartilage grafts using MRI and 3D printing technology. Anatomic grafts demonstrated superior fit compared to generic flat grafts.

LEVEL OF EVIDENCE

Level IV.

Detailed Assessment of Confounders is Necessary for Valid Interpretation of the Results in Patellofemoral Cartilage Restoration Studies

Cartilage restoration procedures have gained increased traction over the years as a treatment for chondral defects in relatively younger patients. A critical assessment of study populations for confounders is vital in order to interpret results in a valid manner. This is particularly true when assessing outcomes of cartilage restoration procedures in the patellofemoral compartment given substantial heterogeneity amongst patients within study populations. Patients often undergo additional procedures (prior or concomitant), have variable anatomy (malalignment, maltracking, and trochlear dysplasia), and variable chondral defect sizes, depths, and locations (lateral patellar facet, medial patellar facet, median patellar ridge, trochlea). Without an assessment of study populations for potential confounders that may influence the results, limited conclusions can be gleaned from any results pertaining to the outcomes of cartilage restoration procedures within the patellofemoral joint. Finally, there are many choices for cartilage restoration (osteochondral autografting, osteochondral allografting, autologous chondrocyte implantation, autologous matrix-induced chondrogenesis and PJAC), different clinical situations where one may confer benefit over the other, yet all seem to result in significant improvement for patients with acceptable failure rates.

Comparison of Minced Cartilage Implantation with Autologous Chondrocyte Transplantation in an In Vitro Inflammation Model

The current gold standard to treat large cartilage defects is autologous chondrocyte transplantation (ACT). As a new surgical method of cartilage regeneration, minced cartilage implantation (MCI) is increasingly coming into focus. The aim of this study is to investigate the influence of chondrogenesis between isolated and cultured chondrocytes compared to cartilage chips in a standardized inflammation model with the proinflammatory cytokine TNFα. Articular chondrocytes from bovine cartilage were cultured according to the ACT method to passage 3 and transferred to spheroid culture. At the same time, cartilage was fragmented (<1 mm3) to produce cartilage chips. TNFα (20 ng/mL) was supplemented to simulate an inflammatory process. TNFα had a stronger influence on the passaged chondrocytes compared to the non-passaged ones, affecting gene expression profiles differently between isolated chondrocytes and cartilage chips. MCI showed less susceptibility to TNFα, with reduced IL-6 release and less impact on inflammation markers. Biochemical and histological analyses supported these findings, showing a greater negative influence of TNFα on the passaged pellet cultures compared to the unpassaged cells and MCI constructs. This study demonstrated the negative influence of TNFα on chondrogenesis in a chondrocyte spheroid culture and cartilage fragment model. Passaged chondrocytes are more sensitive to cytokine influences compared to non-passaged cells and chondrons. This suggests that MCI may have superior regeneration potential in osteoarthritic conditions compared to ACT. Further investigations are necessary for the translation of these findings into clinical practice.

Incidence and Risk Factors for Acute Articular Cartilage Tears in Military and Other Occupational Settings: A Systematic Review

Damage to the articular cartilage resulting in an acute tear can lead to functional changes within the joint and increase the risk of osteoarthritis developing. There is limited understanding of the association between occupational risk factors and sustaining an acute articular cartilage tear in the military and other physically demanding occupations. Therefore, the aim of this systematic review was to identify and evaluate original research reporting on occupational risk factors associated with sustaining acute articular cartilage tears.

METHODS

A systematic review following the Preferred Reporting Items for Systematic review and Meta-Analysis-Protocols was conducted and registered with the Open Science Framework. Key academic databases were searched using terms from the following concepts: risk or cause, paid occupations, and acute articular cartilage tears.

RESULTS

Of an initial 941 studies, 2 studies met the eligibility criteria, both reporting data from military contexts; only one evaluated acute articular cartilage tears in both males and females. One paper focused on articular cartilage injury within the knee and the other within the ankle joint with incidence rates being 0.2 and 0.3 per 1000 person-years, respectively. People in more physically active occupations and individuals with an above-normal body mass index were reported as being at higher risk of sustaining an acute articular cartilage tear.

CONCLUSION

Physically demanding occupations, such as the military, may increase the risk for acute tears of the articular cartilage. However, the findings of this review indicate there is a paucity of research to underpin understanding of the injury mechanisms and occupational risk factors for acute articular cartilage tears.

Outcomes and Return to Sport After Knee Osteochondral Allograft Transplant in Professional Athletes

Background

Limited data are available on the outcomes and return-to-sport rates after osteochondral allograft transplant in professional athletes.

Purpose

To evaluate the experience of a single senior surgeon in treating professional athletes with osteochondral allograft transplant, including analyzing clinical outcomes and return to sport.

Study Design

Case series; Level of evidence, 4.

Methods

The authors performed a retrospective review of professional athletes treated with primary osteochondral allograft to the knee between January 1, 2001, and January 1, 2021, by a single surgeon. Athletes were required to play at the professional level in their sport and have a minimum of 2 years of follow-up. Return-to-sport rates and timing were evaluated. Patient-reported outcomes were assessed preoperatively and at final follow-up. Reoperations and failures were also tabulated.

Results

The study included 15 professional athletes who represented a variety of sports, with follow-up at a mean of 4.91 ± 2.2 years (range, 2.0-9.4 years). The majority (8 athletes; 53%) had undergone prior surgeries to the operative knee. Eleven (73%) returned to sport at a mean of 1.22 ± 0.4 years (range, 0.75-2 years), and of the 8 undergoing isolated osteochondral allograft, 7 (87.5%) returned at 1.28 ± 0.3 years. Ten athletes (66.7% of total; 90.9% of those who returned) returned to sport at the same level or higher compared with before surgery. Significant improvements were seen in each assessed patient-reported outcome score at final follow-up. Two of the 3 (66.7%) patients who underwent concomitant meniscal allograft transplant were able to return to sport at the same level or higher than presurgery. Three (20%) underwent second-look arthroscopy, 1 (6.7%) of whom underwent cartilage debridement of the osteochondral allograft.

Conclusion

Osteochondral allograft transplant in professional athletes can result in a high rate of return to play at a similar or higher level as presurgery, even when performed with concomitant procedures such as meniscal allograft transplant. High-level athletes should expect significant postoperative improvement in clinical outcomes.

Subchondral Bone Alignment in Osteochondral Allograft Transplants for Large Oval Defects of the Medial Femoral Condyle: Comparison of Lateral versus Medial Femoral Condyle Donors

OBJECTIVE

Supply-demand mismatch of medial femoral condyle (MFC) osteochondral allografts (OCAs) remains a rate-limiting factor in the treatment of osteochondral defects of the femoral condyle. Surface contour mapping was used to determine whether a contralateral lateral femoral condyle (LFC) versus ipsilateral MFC OCA differs in the alignment of donor:native subchondral bone for large osteochondral defects of the MFC.

DESIGN

Thirty fresh-frozen human femoral condyles were matched by tibial width into 10 groups of 3 condyles (MFC recipient, MFC donor, and LFC donor) each for 3 cartilage surgeons (90 condyles). The recipient MFC was imaged using nano-computed tomography scan. Donor oval grafts were harvested from each matched condyle and transplanted into a 17 mm × 36 mm defect created in the recipient condyle. Following the first transplant, the recipient condyle was imaged and superimposed on the native condyle nano-CT scan. The donor plug was removed and the process repeated for the other donor. Surface height deviation and circumferential step-off height deviation were compared between native and donor subchondral bone surfaces for each transplant.

RESULTS

There was no statistically significant difference in mean subchondral bone surface deviation (LFC = 0.87 mm, MFC = 0.76 mm, P = 0.07) nor circumferential step-off height (LFC = 0.93 mm, MFC = 0.85 mm, P = 0.09) between the LFC and MFC plugs. There were no significant differences in outcomes between surgeons.

CONCLUSIONS

There were no significant differences in subchondral bone circumferential step-off or surface deviation between ipsilateral MFC and contralateral LFC oval-shaped OCAs for 17 mm × 36 mm defects of the MFC.

Foot Strike Run Retraining for Patients With Patellofemoral Chondral Defects: A Case Series

Military service members (SMs) demonstrate high rates of patellofemoral chondral defects (PFCDs) that are difficult to diagnosis and, if untreated, result in a cascade of events eventually leading to osteoarthritis. Running is an essential occupational task for SMs; however, there is little evidence regarding techniques to maintain running ability in individuals with cartilage defects. The purpose of this case series was to assess the clinical application of foot strike run retraining in patients with PFCDs. This case series included two active duty U.S. Marine Corps SMs who presented to outpatient physical therapy with PFCD, diagnosed via MRI. Both patients attended eight foot strike run retraining sessions. Running mechanics and patient-reported outcomes were recorded pre-training, post-training, and at a 1-month follow-up visit. Both patients successfully converted their strike pattern from a rearfoot to a non-rearfoot strike pattern with training and retained this strategy at 1-month follow-up. Post-intervention, both patients demonstrated increased running tolerance, and improvements in Numeric Pain Rating Scale and Lower Extremity Functional Scale scores. Biomechanical analysis showed that both patients demonstrated a 63% to 70% reduction in average and peak vertical ground reaction force loading rates post-treatment. Modification of foot strike pattern from rear to non-rearfoot strike during running for individuals with PFCD can reduce the magnitude of impact loading, which potentially limits disease progression. These findings suggest that foot strike run retraining may be a feasible strategy to reduce pain and improve function in SMs with PFCD who are required to run for occupational responsibilities.

Positive outcomes following Autologous Matrix-Induced Chondrogenesis (AMIC) in the treatment of retropatellar chondral lesions: a retrospective analysis of a patient registry

BACKGROUND

The patellofemoral joint is a challenging environment for treating chondral defects. Among the surgical options for the treatment of chondral defects, the single-stage Autologous Matrix-Induced Chondrogenesis (AMIC) procedure uses a porcine collagen I/III membrane to enhance bone-marrow stimulation. However, longer term outcomes data are rare for this specific indication. In order to provide real-world information, an ongoing registry has been established to record patient data and outcomes when AMIC is used to treat chondral and osteochondral lesions.

METHODS

Patient data were retrieved from an ongoing, prospective, multisite registry of patients who had undergone AMIC treatment of chondral defects. We identified 64 patients who had undergone AMIC for patellofemoral chondral defects and for whom pre-operative and at least 1 post-operative score were available were included in this retrospective data analysis. Outcomes were assessed via the KOOS, VAS pain, and the Lysholm scores. Outcomes at the post-operative time-points were analysed using a factorial ANOVA with post-hoc testing while linear regression was used to assess associations between the change in the Lysholm score and lesion size.

RESULTS

There was a significant improvement in Lysholm, VAS pain, and KOOS scores from pre-operative to the 1st year post-operative (p < 0.001), and this was maintained during the follow-up.

CONCLUSIONS

The forces exerted on the patellofemoral joint make this a challenging scenario for chondral repair. Our data demonstrates that the AMIC procedure with a collagen I/III membrane is an effective treatment for retropatellar cartilage lesions, and provides reliable results, with decreased pain and improved function. Importantly, these improvements were maintained through the follow-up period.

Satisfactory patient-reported outcomes in patients treated with impaction bone grafting and autologous matrix-induced chondrogenesis for osteochondral knee defects

PURPOSE

Osteochondral knee defects usually affect young, active patients and may alter knee biomechanics and progressively lead to joint degeneration. Various treatment options exist with autologous, impaction bone grafting in combination with autologous matrix-induced chondrogenesis (BG-AMIC) being a less-expensive, one-step, promising option. The purpose of this study is to evaluate the clinical and radiological mid-term outcomes of large osteochondral lesions treated with BG-AMIC, identify a possible correlation between the two and report postoperative complications and reoperation rate.

METHODS

A retrospective analysis of 25 patients treated with the BG-AMIC technique for knee osteochondral lesions was performed. Patients were assessed using the following PROMs: the IKDC, the KOOS and the Lysholm score, the Tegner activity scale and a patient acceptable symptom state (PASS). The EQ-5D-5L score was used to assess health-related quality of life. Radiological assessment was performed using the MOCART 2.0 score on a 3 T MRI.

RESULTS

At a mean of 3.8 (± 0.8)-year follow-up, all functional scores increased significantly (p < 0.005) when compared to the preoperative baseline. IKDC increased from 44.5 (± 15.9) to 81.4 (± 14.7), KOOS from 41.5 (± 16.1) to 91.6 (± 11.6) and Lysholm from 54.4 (± 23) to 95.2 (± 5.5) (p < 0.005). The EQ-5D-5L score also revealed a significant improvement [59.9 (± 25) to 93.4 (± 10.2), p < 0.005]. Mean Tegner score reached pre-injury levels. The PASS was positive in 100% of patients. The minimum clinically important difference was reached in all PROMs except for the KOOS Sports subscale. There were no re-operations. Morphological evaluation of the repair tissue using the MOCART 2.0 score revealed a mean total score of 52.8 (± 30.5). A statistically significant, positive correlation was found between the MOCART 2.0 score and the IKDC score, the KOOS ADL subscale and the EQ-5D-5L (p < 0.05).

CONCLUSION

BG-AMIC is a safe and reliable option for treating deep, knee osteochondral lesions, providing a statistically significant and clinically important improvement in patient-reported outcomes. No complications were noticed, and no re-operations were performed after the procedure. A moderate positive correlation between the MOCART 2.0 score and the IKDC, KOOS ADL and EQ-5D-5L was noticed. However, this correlation is not necessarily clinically relevant, and excellent clinical results can be expected even in patients with low MOCART scores.

LEVEL OF EVIDENCE

III.

Suitable characteristics in the selection of human allogeneic chondrocytes donors to increase the number of viable cells for cartilage repair

Autologous chondrocyte implantation has shown optimal long-term outcomes in the treatment of cartilage lesions. The challenge for a single-stage approach lies in obtaining sufficient number of cells with high viability. The answer could lie in supplementing or replacing them with allogenic chondrocytes coming from cadaveric donors. In the present work, we aimed to compare the number of viable cells isolated from cartilage of live and cadaveric donors and to determine the suitable characteristics of the best donors. A total of 65 samples from donors aged from 17 to 55 years, either women or men, were enrolled in this study (33 living vs. 32 cadaveric). The mean time of hours from death to processing samples in cadaveric donors was higher compared to live donors (64.3 ± 17.7 vs. 4.6±6.4). The number of isolated chondrocytes per gram of cartilage was higher in cadaveric donors (5.389 × 106 compared to 3.067 × 106 in living donors), whereas the average of cell viability was comparable in both groups (84.16% cadaveric, 87.8% alive). It is possible to obtain viable chondrocytes from cartilage harvested from cadaveric donors, reaching a similar cell number and viability to that obtained from the cartilage of living donors.

Effect of Age and Femoral Tunnel Drilling Technique on the Prevalence of Intra-articular Pathology at Both Primary and Revision ACL Reconstruction

Background

Studies have shown that meniscal and chondral lesions are more common at the time of revision anterior cruciate ligament reconstruction (ACLR) compared with primary surgery; however, few have evaluated the same patients through both primary and revision surgery.

Purpose

To describe the prevalence of meniscal and chondral lesions at the time of primary and subsequent revision ACLR and to determine the effect of age and femoral tunnel drilling technique on the development of intra-articular pathology over time.

Study Design

Case series; Level of evidence, 4.

Methods

All patients who had primary and subsequent revision ACLR in the same knee between 1997 and 2022 were identified from a prospectively collated database. The grading of chondral surfaces in each compartment, the presence of any meniscal tears, and treatment performed were recorded. Patients were grouped according to age and femoral tunnel drilling technique to allow subgroup analysis.

Results

Overall, 262 patients were included. Median age at primary surgery was 20.2 years. Lateral meniscal tears were more prevalent than medial tears at both primary (34.7% vs 28.2%; P = .11) and revision surgery (44.3% vs 40.8%; P = .43). Chondral lesions were most frequently found on the patella (8.8%) and the medial femoral condyle (MFC; 8.0%) at primary surgery. Between surgeries, new lesions developed most commonly on the MFC (13.0%) and the lateral femoral condyle (LFC; 11.1%). It was significantly more common for lateral meniscal tears treated with repair or left in situ at primary surgery to be healed at the time of revision surgery than medial tears (P = .01). Significantly more patients who had transtibial drilling of the femoral tunnel had a new meniscal tear at revision surgery (P = .001). Age did not have a significant influence on the prevalence of meniscal pathology.

Conclusion

The prevalence of intra-articular pathology increased between primary and revision ACLR. Lateral meniscal tears were more prevalent than medial tears at both surgeries. At revision surgery, new chondral lesions were more commonly found on the MFC than the LFC. The higher incidence of new meniscal tears observed in the transtibial group may reflect the more vertical graft orientation with this technique and its inferior ability to control rotation.

Meniscal and Chondral Injury Patterns in Athletes With Anterior Cruciate Ligament Tear

Anterior cruciate ligament (ACL) tears are a prevalent and debilitating injury among athletes, often accompanied by concurrent meniscal and chondral injuries. This study aimed to present a comprehensive investigation into the patterns and prevalence of meniscal and chondral injuries in athletes with ACL tears. This is a cross-sectional study conducted on 600 athletic patients with ACL tears planned for reconstruction in a duration of five years. A combination of advanced imaging techniques, arthroscopic evaluations, and clinical data was used to provide a comprehensive understanding of the injury profiles of the participant athletes. Those findings were duly recorded and analyzed accordingly. Out of 600 patients, 67% (402) had at least one meniscal or chondral injury while the rest 33% (198) had isolated ACL injuries only. Of the patients, 18% (108) were those who had both meniscal and chondral injuries present. Amongst the 57% (342) of patients who had meniscal injuries, injuries to the medial meniscus, lateral meniscus, and both the meniscus were present in 51% (175), 32% (109), and 17% (58) of patients, respectively. Amongst all associated meniscal injuries (n1 = 404), around 52% (210) tears were present in the body of the meniscus, 31% (125) in the posterior horn, and 17% (69) in the anterior horn. Overall, it was noted that 22.77% (92) of meniscal tears were bucket handle tears of the medial meniscus, 16.08% (65) were complex tears of the posterior horn of the lateral meniscus, and 9.60% (39) were complex tears of the posterior horn of the medial meniscus. Amongst 600 patients, 28% (168) of patients had at least one chondral injury present in association with ACL tear. Further, amongst the total number of chondral lesions reported (n2 =297) in ACL-deficient knees, around 55% (163) of lesions were located on medial femoral condyle, 10% (30) were located on undersurface of patella, 10% (30) were global changes, 7% (20) were on lateral femoral condyle, and 5% (15) were located on medial articulating surface of knee. A total of 61% (181) of chondral lesions were grade II, 21% (62) were grade III, 10%(30) were grade IV, and the least noted were 8% (24) grade I chondral lesions. The study concludes that medial meniscus injury was the most common meniscal injury in ACL-deficient knees and the bucket handle tear of the medial meniscus was the most common type of meniscal tear followed by the complex tear of the posterior horn of the medial meniscus. Further, the study also concludes that the medial femoral condyle is the most common site of chondral lesions in ACL-deficient knees.

Preclinical Cartilage Changes of the Knee Joint in Adolescent Competitive Volleyball Players: A Prospective T2 Mapping Study

PURPOSE

To investigate the potential effects of volleyball as a competitive sport in adolescence on the cartilage of knee joints using T2 mapping in MRI and identification of preclinical cartilage changes. Volleyball as an impact sport often leads to damage of the knee joint cartilage in adulthood. As T2 mapping is widely available and highly capable of detecting cartilage changes prior to conventional MRI sequences, such a detection may allow adolescent volleyball players to change their training regime before structural damage can occur to the cartilage and pose the risk of osteoarthritis.

MATERIALS AND METHODS

Comparative study of the patellar, femoral, and tibial cartilage of 60 knee joints using T2 mapping on 3 T MRI. In each case, both knees of 15 adolescent competitive volleyball athletes were compared with 15 controls.

RESULTS

In the group of competitive athletes, more focal cartilage changes were detected in the medial facet of the patellofemoral cartilage and in the medial femoral condyle of the knee joint cartilage (p = .01 and p <.05, respectively). Furthermore, the latter showed a diffused increase in maximal T2 mapping values (p <.04 right and p = .05 left). The distribution of changes seems to further depend on the player's position.

CONCLUSION

In adolescent volleyball players in competitive sports, T2 mapping demonstrates early cartilage changes in both the patellofemoral and medial femoral cartilages. The distribution of lesions depends on the player's position. Since the cascade from T2 relaxation time increase to conspicuous cartilage damage is well established, early counter-regulation (e. g., adapted training profile, targeted physiotherapy, and appropriate muscle building training) has the potential to prevent later damage.

KEY POINTS

· Volleyball as a competitive sport in adolescence leads to preclinical knee cartilage changes.. · Cartilage changes are both focal and diffuse.. · Jumping-intensive player positions seem to show more patellofemoral and running-intensive more condylar cartilage changes.. · Early detection of these changes could prevent progression to cartilage damage through adapted training..

CITATION FORMAT

· Roth C, Hirsch F, Sorge I et al. Preclinical Cartilage Changes of the Knee Joint in Adolescent Competitive Volleyball Players: A Prospective T2 Mapping Study. Fortschr Röntgenstr 2023; 195: 913 - 923.

Comparison of multiple synthetic chondroinductive factors in pellet culture against a TGF-β positive control

Despite the advances in surgical and cell therapy regenerative techniques for cartilage repair, the challenge is to overcome an inferior fibrocartilage repair tissue. In vitro, TGF-β1 and TGF-β3 are the primary growth factors employed to induce chondrogenic differentiation. However, the clinical application of native proteins may present challenges regarding stability, cost, or reproducibility. Therefore, there remains an unmet clinical need for the identification of small chondroinductive synthetic molecules. From the literature, two peptides-CM10 and CK2.1-appear to be promising candidates; however, they have not been directly compared to TGF-β with human bone marrow-derived stem cells (hBMSCs). Similarly, two promising compounds-kartogenin and SM04690-have been reported in the literature to exhibit chondroinductive potential in vivo and in vitro; however, kartogenin was not directly compared against TGF-β. In the current study, we evaluated the chondroinductive potential of CM10, CK2.1, kartogenin, and SM04690, and directly compared them to each other and to a TGF-β3 positive control. Following 21 days of culture, none of the evaluated chondrogenic factors, either individually or even in combinations of two, resulted in a higher gene expression of chondrogenic markers as compared to TGF-β3. Additionally, no collagen II gene expression was detected except in the TGF-β3 positive control group. Given that the evaluated factors have confirmed efficacy in the literature, but not in the current study with a positive control, there may be value in the future identification of new chondroinductive factors that are less situation-dependent, with rigorous evaluations of their effect on chondrogenesis using positive controls.

Comparison of Knee Articular Cartilage Defect Size Between Measurements Obtained on Preoperative MRI Versus During Arthrotomy

Background

Treatment decisions for cartilage defects are often based on lesion size. Magnetic resonance imaging (MRI) is widely used to diagnose cartilage defects noninvasively; however, their size estimated from MRI may differ from defect sizes measured during arthrotomy, especially after debridement to healthy cartilage if undergoing autologous chondrocyte implantation.

Purpose/Hypothesis

The purpose of this study was to evaluate the reliability of 2 methods to assess knee cartilage defect size on preoperative MRI and determine their accuracy in predicting postdebridement defect sizes recorded during arthrotomy. It was hypothesized that defect size would be predicted more accurately by the total area of abnormal articular cartilage rather than the area of full-thickness cartilage loss as identified on MRI.

Study Design

Cohort study (diagnosis); Level of evidence, 3.

Methods

This study included 64 patients (mean age, 41.8 ± 9.6 years) who underwent autologous cell therapy. Each patient received a 3-T MRI at 6.1 ± 3.0 weeks before cell implantation. Three raters, a radiologist, a surgeon, and a scientist, measured (1) the full-thickness cartilage defect area and (2) the total predicted abnormal cartilage area, identified by an abnormal signal on MRI. Interrater reliability was assessed using the intraclass correlation coefficient (ICC). Actual pre- and postdebridement defect sizes were obtained from intraoperative surgical notes. Postdebridement surgical measurements were considered the clinical reference standard and were compared with the radiologist's MRI measurements.

Results

Eighty-seven defects were assessed, located on the lateral (n = 8) and medial (n = 26) femoral condyle, trochlea (n = 17), and patella (n = 36). The interrater reliability of the cartilage defect measurements on MRI was good to excellent for the full-thickness cartilage defect area (ICC = 0.74) and the total predicted abnormal cartilage area (ICC = 0.78). The median full-thickness cartilage defect area on MRI underestimated the median postdebridement defect area by 78.3%, whereas the total predicted abnormal cartilage area measurement underestimated the postdebridement defect area by 14.3%.

Conclusion

Measuring the full-thickness cartilage defect area on MRI underestimated the area to treat, whereas measuring the total abnormal area provided a better estimate of the actual defect size for treatment.

Mesenchymal Stem Cells: Generalities and Clinical Significance in Feline and Canine Medicine

Mesenchymal stem cells (MSCs) are multipotent cells: they can proliferate like undifferentiated cells and have the ability to differentiate into different types of cells. A considerable amount of research focuses on the potential therapeutic benefits of MSCs, such as cell therapy or tissue regeneration, and MSCs are considered powerful tools in veterinary regenerative medicine. They are the leading type of adult stem cells in clinical trials owing to their immunosuppressive, immunomodulatory, and anti-inflammatory properties, as well as their low teratogenic risk compared with pluripotent stem cells. The present review details the current understanding of the fundamental biology of MSCs. We focus on MSCs' properties and their characteristics with the goal of providing an overview of therapeutic innovations based on MSCs in canines and felines.

Assessment of Patellar Vascularity after Patellar Cartilage Restoration via Lateral Parapatellar Approach: Analysis Using Dynamic Contrast-Enhanced Magnetic Resonance Imaging

OBJECTIVE

Patellofemoral cartilage restoration procedures, including osteochondral allograft, particulated juvenile cartilage, and matrix-induced autologous chondrocyte implantation, have been shown to be effective treatments for patellofemoral cartilage lesions. However, concerns exist regarding disruption of the patellar vascular supply and secondary stabilizers of the patellofemoral joint during medial parapatellar approaches, especially when combined with a lateral release. A lateral parapatellar approach affords the possibility of avoiding disruption of the medial blood supply to the patella, while also allowing laterally-based soft tissue stabilization procedures. The purpose of this study was to investigate in vivo changes in patellar vascularity following patellofemoral cartilage restoration procedures performed via a lateral parapatellar approach via use of dynamic contrast-enhanced magnetic resonance (MR) imaging.

DESIGN

This study is a prospective case series of 5 adult patients undergoing patellofemoral cartilage restoration procedures via a lateral parapatellar approach with pre-operative and post-operative dynamic contrast-enhanced MR imaging to assess changes in patellar vascularity. Secondary outcomes included knee range of motion, need for revision surgery, and complications.

RESULTS

There was no significant post-operative difference in patellar vascularity in patients undergoing patellofemoral cartilage restoration procedures via a lateral parapatellar approach, as evaluated by qualitative MR imaging.

CONCLUSION

Our results suggest that a lateral parapatellar approach for cartilage restoration procedures may preserve patellar vascularity, while also allowing for lateral release to be performed through the same incision.

[Knee cartilage injuries in athletes]

BACKGROUND

Acute and chronic cartilage injuries are often encountered in professional and recreational athletes. They can compromise the athlete's performance and career and are considered a potential risk factor for early joint degeneration.

OBJECTIVES

Incidence of cartilage injury in athletes, understanding of cartilage composition, injury mechanism and suitable diagnostic imaging are summarized and established therapeutic procedures, postoperative imaging including detection of relevant complications and assessment of reasonable indications for follow-up examinations are described.

METHODS

Original research and review articles were analyzed.

RESULTS

Cartilage injury can mimic meniscal or ligamentous injury and cannot be ruled out by clinical examination alone. Magnetic resonance imaging (MRI) is the method of choice to (1) detect (sensitivity 87-93%, specificity 94-99%) and grade cartilage lesions to facilitate choice of therapy and (2) to exclude concomitant injuries that require treatment to improve the prognosis of the chosen cartilage therapy. Postoperatively MRI allows noninvasive assessment of the repaired cartilage tissue and is an appropriate method to detect therapeutically relevant complications.

CONCLUSIONS

Knowledge of mechanisms and appearance of cartilage injuries, current cartilage repair techniques and their imaging is crucial for the medical care of athletes.

Revision Lateral Femoral Condyle Osteochondral Allograft Transplantation With the Snowman Technique After Failed Previous Oblong Osteochondral Allograft

Osteochondral allograft transplantation provides components of both cartilage and subchondral bone and can be used in large and multifocal defects where autologous procedures are limited by donor-site morbidity. Osteochondral allograft transplantation is particularly appealing in the management of failed cartilage repair, as larger defects and subchondral bone involvement are often present, and the use of multiple overlapping plugs might be considered. The described technique provides our preoperative workup and reproducible surgical approach for patients who have undergone previous osteochondral transplantation with graft failure and are young, active patients who would not be otherwise suited for a knee arthroplasty procedure.

Return to Pivoting Sports after Cartilage Repair Surgery of the Knee: A Scoping Review

OBJECTIVE

To perform a scoping literature review evaluating and reporting on outcomes and return to pivoting sports after cartilage procedures. For this review, the following cartilage procedures were evaluated: microfracture, osteochondral autograft transplantation (OAT), osteochondral allograft transplantation (OCA), and autologous chondrocyte implantation (ACI).

DESIGN

The scoping review incorporated articles identified using PubMed (MEDLINE), CINAHL, and Cochrane Central Register of Controlled Trials. Screening of reference lists of included studies and forward citation tracking were performed to identify additional studies. Reported on return to pivoting sports after cartilage surgery written in English language.

RESULTS

Sixteen studies fulfilled the inclusion criteria. The return to sports (RTS) rates after microfracture ranged from 44% to 83%, and to preinjury level from 25% to 75%. The RTS rates after OAT ranged from 87% to 100%, and to preinjury level from 67% to 93%. The RTS rates after OCA ranged from 77% to 80%, and to preinjury level 64%. The RTS rates after ACI ranged from 33% to 96%, and to preinjury level from 26% to 67%.

CONCLUSIONS

There was a high heterogeneity and range in rates of RTS in athletes participating in pivoting sports. Most studies reported high rates of RTS; however, return to preinjury level was lower. These data may be important to clinicians in shared decision making on the type of procedure to be performed and counseling pivoting sports athletes on prognosis and expected RTS rates.

The Large Focal Isolated Chondral Lesion

Focal chondral defects (FCDs) of the knee can be a debilitating condition that can clinically translate into pain and dysfunction in young patients with high activity demands. Both the understanding of the etiology of FCDs and the surgical management of these chondral defects has exponentially grown in recent years. This is reflected by the number of surgical procedures performed for FCDs, which is now approximately 200,000 annually. This fact is also apparent in the wide variety of available surgical approaches to FCDs. Although simple arthroscopic debridement or microfracture are usually the first line of treatment for smaller lesions, chondral lesions that involve a larger area or depth require restorative procedures such as osteochondral allograft transplantation or other cell-based techniques. Given the prevalence of FCDs and the increased attention on treating these lesions, a comprehensive understanding of management from diagnosis to rehabilitation is imperative for the treating surgeon. This narrative review aims to describe current concepts in the treatment of large FCDs through providing an algorithmic approach to selecting interventions to address these lesions as well as the reported outcomes in the literature.

Effect of recombinant Sox9 protein on the expression of cartilage-specific genes in human dermal fibroblasts cell culture

Introduction: Damage to the hyaline layer of large joints resulting from injuries or age-related changes restricts their mobility. The repair of these disorders is an actual issue in medicine. One of the promising therapies is the usage of cell engineering constructs based on a biodegradable scaffold and a modified cell culture. A frequently used method to modify the proliferation of cell culture for tissue engineering of hyaline cartilage, which makes it possible to introduce an experimental technique into clinical practice, is the application of recombinant proteins that affect chondrogenesis and lead to increase synthesis of extracellular matrix proteins. The goal of this work was to elucidate the effect of the key transcription factor in the chondrogenesis process – Sox9 protein – on the expression of genes responsible for chondrogenesis (Tgfβ3, Sox9, Acan, Comp, Col2a1).

Materials and methods: Human dermal fibroblasts were used as a cell culture; recombinant Sox9 was added at each change of medium; the modification was carried out for 21 days, and difference in gene expression was determined by real-time PCR and -ΔΔCt method.

Results and discussion: To assess the effectiveness of fibroblast modification, we analyzed the changing of expression of genes responsible for chondrogenesis (Tgfß3, Sox9, Col2a1, Acan, Comp). We studied the direct effect of different concentrations of the recombinant Sox9 protein on the proliferation of dermal fibroblasts in the chondrogenic direction. We showed that the addition of the recombinant Sox9 protein in various concentration did not significantly change the expression of both the genes encoding proteins of the extracellular matrix of hyaline cartilage (Acan, Col2a1, Comp) and the genes encoding chondrogenesis inducers (Tgfß3, Sox9).

Conclusion: As a result of the experiments, it was shown that the recombinant Sox9 protein has practically no effect on chondrogenic differentiation and does not significantly change the expression of chondrogenesis genes.

Proteomic, mechanical, and biochemical development of tissue-engineered neocartilage

Background

The self-assembling process of cartilage tissue engineering is a promising technique to heal cartilage defects, preventing osteoarthritic changes. Given that chondrocytes dedifferentiate when expanded, it is not known if cellular expansion affects the development of self-assembled neocartilage. The objective of this study was to use proteomic, mechanical, and biochemical analyses to quantitatively investigate the development of self-assembled neocartilage derived from passaged, rejuvenated costal chondrocytes.

Methods

Yucatan minipig costal chondrocytes were used to create self-assembled neocartilage constructs. After 1, 4, 7, 14, 28, 56, or 84 days of self-assembly, constructs were analyzed through a variety of histological, biomechanical, biochemical, and proteomic techniques.

Results

It was found that temporal trends in neocartilage formation are similar to those seen in native hyaline articular cartilage development. For example, between days 7 and 84 of culture, tensile Young’s modulus increased 4.4-times, total collagen increased 2.7-times, DNA content decreased 69.3%, collagen type II increased 1.5-times, and aggrecan dropped 55.3%, mirroring trends shown in native knee cartilage. Importantly, collagen type X, which is associated with cartilage calcification, remained at low levels (≤ 0.05%) at all neocartilage developmental time points, similar to knee cartilage (< 0.01%) and unlike donor rib cartilage (0.98%).

Conclusions

In this work, bottom-up proteomics, a powerful tool to interrogate tissue composition, was used for the first time to quantify and compare the proteome of a developing engineered tissue to a recipient tissue. Furthermore, it was shown that self-assembled, costal chondrocyte-derived neocartilage is suitable for a non-homologous approach in the knee.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40824-022-00284-4.

Molecular mechanisms of exercise contributing to tissue regeneration

Physical activity has been known as an essential element to promote human health for centuries. Thus, exercise intervention is encouraged to battle against sedentary lifestyle. Recent rapid advances in molecular biotechnology have demonstrated that both endurance and resistance exercise training, two traditional types of exercise, trigger a series of physiological responses, unraveling the mechanisms of exercise regulating on the human body. Therefore, exercise has been expected as a candidate approach of alleviating a wide range of diseases, such as metabolic diseases, neurodegenerative disorders, tumors, and cardiovascular diseases. In particular, the capacity of exercise to promote tissue regeneration has attracted the attention of many researchers in recent decades. Since most adult human organs have a weak regenerative capacity, it is currently a key challenge in regenerative medicine to improve the efficiency of tissue regeneration. As research progresses, exercise-induced tissue regeneration seems to provide a novel approach for fighting against injury or senescence, establishing strong theoretical basis for more and more "exercise mimetics." These drugs are acting as the pharmaceutical alternatives of those individuals who cannot experience the benefits of exercise. Here, we comprehensively provide a description of the benefits of exercise on tissue regeneration in diverse organs, mainly focusing on musculoskeletal system, cardiovascular system, and nervous system. We also discuss the underlying molecular mechanisms associated with the regenerative effects of exercise and emerging therapeutic exercise mimetics for regeneration, as well as the associated opportunities and challenges. We aim to describe an integrated perspective on the current advances of distinct physiological mechanisms associated with exercise-induced tissue regeneration on various organs and facilitate the development of drugs that mimics the benefits of exercise.

In elite athletes with meniscal injuries, always repair the lateral, think about the medial! A systematic review

PURPOSE

This study aimed to evaluate and compare the time required to return to sports (RTS) after surgery, the rate of revision surgery and the time required for RTS after revision surgery in elite athletes undergoing meniscal repair or partial meniscectomy, particularly analysing the difference between medial and lateral menisci. It was hypothesised that both procedures would entail similar, high rates of RTS, with the lateral meniscus exhibiting higher potential healing postprocedure compared to the medial meniscus.

METHODS

A systematic review was conducted based on the PRISMA guidelines. Quality assessment of the systematic review was performed using the AMSTAR-2 checklist. The following search terms were browsed in the title, abstract and keyword fields: 'meniscus' or 'meniscal' AND 'tear,' 'injury' or 'lesion' AND 'professional,' 'elite' or 'high-level' AND 'athletes,' 'sports,' 'sportsman,' 'soccer,' 'basketball,' 'football' or 'handball'. The resulting measures extracted from the studies were the rate of RTS, level of RTS, complications, revision surgery and subsequent RTS, Tegner, International Knee Documentation Committee (IKDC) and Visual Analogue Scale (VAS).

RESULTS

In this study, the cohort consisted of 421 patients [415 (98.6%) men and 6 (1.4%) women] with a mean age of 23.0 ± 3.0 years. All patients were elite athletes in wrestling, baseball, soccer, rugby or handball. While 327 (77.7%) patients received partial meniscectomy at a mean age of 23.3 ± 2.6 years, 94 (22.3%) patients received meniscal repair at a mean age of 22.1 ± 4.0 years. After partial meniscectomy, 277 patients (84.7%) returned to their competitive sports activity and 256 (78.3%) returned to their pre-injury activity levels. A total of 12 (3.7%) patients required revision surgery because of persistent pain [5 (1.5%) patients], chondrolysis [2 (0.7%) patients] or both chondrolysis and lateral instability [5 (1.5%) patients]. Ten (83.3%) of the twelve patients had involvement of the lateral meniscus, whereas the location of injury was not specified in the remaining two patients. After revision surgery, all patients (100%) resumed sports activity. However, after meniscal repair, 80 (85.1%) athletes returned to their competitive sports activity and 71 (75.5%) returned to their pre-injury activity levels. A total of 16 (17.0%) patients required partial meniscectomy in cases of persistent pain or suture failure. Of these, 4 (25%) patients involved lateral and medial menisci each and 8 (50%) patients were not specified. After revision surgery, more than 80.0% of the patients (13) resumed sports activity.

CONCLUSIONS

In elite athletes with isolated meniscal injury, partial meniscectomy and meniscal suture exhibited similar rates of RTS and return to pre-injury levels. Nonetheless, athletes required more time for RTS after meniscal repair and exhibited an increased rate of revision surgery associated with a reduced rate of RTS after the subsequent surgery. For lateral meniscus tears, meniscectomy was associated with a high rate of revision surgery and risk of chondrolysis, whereas partial medial meniscectomy allowed for rapid RTS but with the potential risk of developing knee osteoarthritis over the years. The findings of this systematic review suggested a suture on the lateral meniscus in elite athletes because of the high healing potential after the procedure, the reduced risk of developing chondrolysis and the high risk of revision surgery after partial meniscectomy. Furthermore, it is important to evaluate several factors while dealing with the medial meniscus. If rapid RTS activity is needed, a hyperselective meniscectomy is recommended; otherwise, a meniscal suture is recommended to avoid accelerated osteoarthritis.

LEVEL OF EVIDENCE

Level IV.

STUDY REGISTRATION

PROSPERO-CRD42022351979 ( https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=351979 ).

Osteochondral Allograft Transplant for Combined Medial and Lateral Patellar Cartilage Lesions: The Osteochondral Wide Lesion (OWL) Technique

Symptomatic articular cartilage injuries are often seen in young active patients and athletes. Magnetic resonance imaging screening examinations have frequently identified such lesions in athletic patients. Patellofemoral chondral defects were previously identified as the most common knee cartilage lesion in high-level athletes. Chondral defects measuring 2 cm² or greater and complex cartilage defects involving bone loss are ideally replaced with fresh osteochondral allograft. We describe a technique indicated for patients with symptomatic and recurrent anterior knee pain associated with osteochondral patellar defects including the lateral and medial patellar facets. Patients who have undergone previous interventions, including membrane techniques, microfracture, or autologous chondral transplantation, without clinical benefit are also eligible to undergo osteochondral allograft transplantation for combined medial and lateral patellar cartilage lesions, that is, the osteochondral wide lesion (OWL) technique.

Magnetic resonance imaging is able to detect patellofemoral focal cartilage injuries: a systematic review with meta-analysis

PURPOSE

The purpose of this study was to analyze the diagnostic accuracy of magnetic resonance imaging (MRI) to detect and grade the severity of patellofemoral (PF) cartilage injuries.

METHODS

A systematic review was conducted on PubMed, EMBASE and Cochrane Library databases (up to July 1st 2022) to search for studies that reported the diagnostic accuracy of MRI to detect and grade PF cartilage injuries as compared to diagnostic arthroscopy. Risk of bias was judged using the QUADAS-2 tool. Quantitative syntheses were performed to calculate the diagnostic accuracy metric-sensitivity, specificity, positive likelihood (LR+) and negative likelihood (LR-) ratios, diagnostic odds ratio (DOR)-and presented as median with 25% and 75% percentiles. The summary receiver operating characteristic (SROC) curves were also calculated. Diagnostic accuracy metrics were calculated for all PF cartilage injuries and then sub-grouped by patellar and trochlear lesions. Diagnostic accuracy was also calculated according to the grading of cartilage injuries.

RESULTS

Forty-five studies were included for qualitative analyses and forty studies were included for quantitative synthesis. A total of 3534 participants with a weighted mean age of 38.1 years were included. Diagnostic accuracy was generally high: sensitivity (0.8, 0.6-1.0), specificity (0.9, 0.8-1.0), LR+ (6.4, 3.1-15.3), LR- (0.3, 0.2-0.4) and DOR (21.3, 9.9-121.1). The area under the curve (AUC) of the SROC was 0.9. The diagnostic accuracy was slightly higher for patellar (sensitivity 0.8, specificity 0.8, LR+ 5.3, LR- 0.2, DOR 28.8) than for trochlear lesions (sensitivity 0.7, specificity 0.9, LR+ 5.5, LR- 0.4, DOR 14.3). The sensitivity was generally higher when grading advanced (vs. early or intermediate) cartilage injuries of the patella.

CONCLUSION

The MRI is able to diagnose PF cartilage injuries with reasonably high diagnostic accuracy (as compared to arthroscopy). Clinicians can rely on MRI to reliably diagnose PF cartilage injuries (with some limitations) which will play an important role in deciding for surgical or non-operative treatment.

LEVEL OF EVIDENCE

Level III.

Implementation of Photosensitive, Injectable, Interpenetrating, and Kartogenin-Modified GELMA/PEDGA Biomimetic Scaffolds to Restore Cartilage Integrity in a Full-Thickness Osteochondral Defect Model

Cartilage defects caused by mechanical tear and wear are challenging clinical problems. Articular cartilage has unique load-bearing properties and limited self-repair ability. The current treatment methods, such as microfractures and autogenous cartilage transplantation to repair full-thickness cartilage defects, have apparent limitations. Tissue engineering technology has the potential to repair cartilage defects and directs current research development. To enhance the regenerative capacities of cartilage in weight-bearing areas, we attempted to develop a biomimetic scaffold loaded with a chondroprotective factor that can recreate structure, restore mechanical properties, and facilitate anabolic metabolism in larger joint defects. For enhanced spatial control over both bone and cartilage layers, it is envisioned that biomaterials that meet the needs of both tissue components are required for successful osteochondral repair. We used gelatin methacrylate (GELMA) and polyethylene glycol diacrylate (PEGDA) light-cured dual-network cross-linking modes that can significantly increase the mechanical properties of scaffolds and are capable of restoring function and prolonging the degradation time. Once the hydrogel complex was injected into the osteochondral defect, in situ UV light curing was applied to seamlessly connect the defect repair tissue with the surrounding normal cartilage tissue. The small molecule active substance kartogenin (KGN) can promote cartilage repair. We encapsulated KGN in biomimetic scaffolds so that, as the scaffold degrades, scaffold-loaded KGN was slowly released to induce endogenous mesenchymal stem cells to home and differentiate into chondrocytes to repair defective cartilage tissue. Our experiments have proven that, compared with the control group, GELMA/PEGDA + KGN repaired cartilage defects and restored cartilage to hyaline cartilage. Our study suggests that implementing photosensitive, injectable, interpenetrating, and kartogenin-modified GELMA/PEDGA biomimetic scaffolds may be a novel approach to restore cartilage integrity in full-thickness osteochondral defects.

A Genome-Wide Association Study Reveals Two Genetic Markers for Chondromalacia

OBJECTIVE

It is unknown why some athletes develop chondromalacia and others do not, even when accounting for similar workloads between individuals. Genetic differences between individuals may be a contributing factor. The purpose of this work was to screen the entire genome for genetic markers associated with chondromalacia.

DESIGN

Genome-wide association (GWA) analyses were performed utilizing data from the Kaiser Permanente Research Board (KPRB) and the UK Biobank. Chondromalacia cases were identified based on electronic health records from KPRB and UK Biobank. GWA analyses from both cohorts were tested for chondromalacia using a logistic regression model adjusting for sex, height, weight, age of enrollment, and race/ethnicity using allele counts for single-nucleotide polymorphisms (SNPs). The data from the 2 GWA studies (KPRB and UK Biobank) were combined in a meta-analysis.

RESULTS

There were a total of 3,872 combined cases of chondromalacia from the KPRB and the UK Biobank cohorts. Genome-wide significant associations with chondromalacia were found for rs144449054 in the ARHGAP15 gene (OR = 3.70 [2.32-5.90]; P = 1.4 × 10^-8) and rs188900564 in the MAGEC2 (OR = 2.07 [1.61-2.65]; P = 3.7 × 10^-9).

CONCLUSIONS

Genetic markers in ARHGAP15 and MAGEC2 appear to be associated with chondromalacia and are potential risk factors that deserve further validation regarding molecular mechanisms.

Treatment of Cartilage Defects of the Knee in Military Tactical Athletes: An Overview of Management and Clinical Outcomes

Cartilage defects of the knee are a common problem that can be caused by trauma or chronic repetitive overload and result in debilitating functional limitations. These consequences are of particular significance to military service members, who, by in large, are a group of young, active individuals with professional duties requiring full, unrestricted activity and function. The burden of knee chondral-related disease among military tactical athletes is well established, and systematic approach to the evaluation of a military member with suspected knee chondral pathology facilitates the execution of a surgical procedure that maximizes the likelihood of a return to duty. Despite advances in cartilage restoration surgery, chondral pathology of the knee remains a vexing problem and an omnipresent threat to military medical readiness and warfighter lethality.

Incidence, Timing, and Risk Factors for 5-Year Revision Surgery After Autologous Chondrocyte Implantation in 533 Patients

BACKGROUND

Autologous chondrocyte implantation (ACI) can be used to treat focal, full-thickness chondral defects of the knee. However, there is limited large-sample evidence available regarding the incidence, timing, and risk factors for revision surgery after ACI.

PURPOSE

To assess the 5-year incidence, timing, and risk factors for revision surgery after ACI in a large national cohort.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

The 2010-2020 PearlDiver database was queried for patients aged 20 to 59 years who underwent primary ACI of the knee without previous chondral procedures or knee arthroplasty. Revision surgery was defined as subsequent revision ACI, osteochondral allograft transplantation, osteochondral autograft transfer, unicompartmental knee arthroplasty, or total knee arthroplasty within 5 years. Kaplan-Meier analysis was used to assess both incidence and timing of revision surgery. Risk factors evaluated for revision surgery included patient age, sex, body mass index (BMI), Elixhauser Comorbidity Index (ECI) score, and previous or concomitant bony realignment procedures.

RESULTS

In total, 533 patients underwent primary ACI and met inclusion criteria. The 5-year incidence of revision surgery was 10.3%, with 63% of revisions occurring in the first 2 years after surgery. Risk factors associated with revision surgery included female sex (odds ratio, 2.58; 95% CI, 1.22-5.45; P = .013) and BMI ≥35 (odds ratio, 2.24; 95% CI, 1.01-4.94; P = .047). There was no relationship between age, ECI score, or previous or concomitant bony realignment procedures and revision surgery at 5 years (P > .05).

CONCLUSION

In an analysis of 533 patients who underwent ACI, 10.3% required a subsequent articular cartilage procedure or conversion to knee arthroplasty in the first 5 postoperative years. Revision surgery was greatest in the first 2 postoperative years. Female sex and severe obesity (BMI, ≥35) were associated with increased risk of revision surgery, while age, ECI score, and previous or concomitant bony realignment procedures were not. These findings suggest that treatment of chondral defects of the knee with ACI is associated with durable outcomes at the 5-year follow-up.

Surgical therapy in osteoarthritis

OBJECTIVE

To provide an evidence-based overview of the different surgical procedures in osteoarthritis (OA).

DESIGN

This narrative review reports on surgical therapies (1) for severe, end stage OA and (2) of surgical options aiming to possibly reduce OA development earlier in the course of the disease.

RESULTS

Surgical practice guidelines provide evidence-based recommendations to assist in the clinical decision-making. Total joint arthroplasty represents the only valuable, established surgical option for severe, end stage OA. For hip and knee OA, it is by far the most common surgical procedure and provides considerable pain relief, functional restoration, and improved quality of life. Surgical therapy aiming to postpone OA essentially addresses extra- or intraarticular pre-osteoarthritic deformities, defined as congenital or acquired disturbances of the joint structure that adversely affect its function. Approaches in this category include osteotomies and different cartilage repair procedures such as osteochondral autograft and allograft transfer, marrow stimulation techniques, and autologous chondrocyte implantation. However, they are not only less commonly performed than arthroplasty, but the scientific clinical evidence in favour of this type of surgery to reduce the long-term risk of developing OA is considerably reduced.

CONCLUSION

Total knee and hip arthroplasty are two of the most successful procedures in all of medicine. As the progression of this insidious disease is often asymptomatic and slow, it is imperative to judge reparative procedures at their potential to reduce OA development at long-term, besides their primary clinical outcomes. Evidence-based guidelines provide a valuable tool for high-quality surgical decision making in OA.

Management Considerations for Unicompartmental Osteoarthritis in Athletic Populations: A Review of the Literature

Unicompartmental osteoarthritis in the young athlete poses a challenge for both patients and providers. Coronal plane malalignment is frequently a concomitant finding that adds to the complexity of management. Military surgeons are presented unique challenges, in that they must consider optimal joint-preservation methods while returning patients to a high-demand occupational function. Management options range from lifestyle changes to surgical interventions. We present a concise review of the available literature on this subject, with a specific focus on indications and outcomes within the military and young athletic population.

Biomaterial-Based Therapeutic Approaches to Osteoarthritis and Cartilage Repair Through Macrophage Polarization

There is an ever-increasing clinical and socioeconomic burden associated with cartilage lesions & osteoarthritis (OA). Its progression, chondrocyte death & hypertrophy are all facilitated by inflamed synovium & joint environment. Due to their capacity to switch between pro- & anti-inflammatory phenotypes, macrophages are increasingly being recognized as a key player in the healing process, which has been largely overlooked in the past. A biomaterial's inertness has traditionally been a goal while developing them in order to reduce the likelihood of adverse reactions from the host organism. A better knowledge of how macrophages respond to implanted materials has made it feasible to determine the biomaterial architectural parameters that control the host response & aid in effective tissue integration. Thus, this review summarizes novel therapeutic techniques for avoiding OA or increasing cartilage repair & regeneration that might be developed using new technologies tuning macrophages into desirable functional phenotypes.

No evidence in support of arthroscopic partial meniscectomy in adults with degenerative and nonobstructive meniscal symptoms: a level I evidence-based systematic review

PURPOSE

It is unclear whether the results of arthroscopic partial meniscectomy (APM) are comparable to a structured physical therapy (PT). This systematic review investigated efficacy of APM in the management of symptomatic meniscal damages in middle aged patients. Current available randomised controlled trials (RCTs) which compared APM performed in isolation or combined with physical therapy versus sham arthroscopy or isolated physical therapy were considered in the present systematic review.

METHODS

This systematic review was conducted according to the 2020 PRISMA statement. All the level I RCTs which investigated the efficacy of AMP were accessed. Studies which included elderlies with severe OA were not eligible, nor were those in which APM was combined with other surgical intervention or in patients with unstable knee or with ligaments insufficiency. The risk of bias was assessed using the software Review Manager 5.3 (The Nordic Cochrane Collaboration, Copenhagen). To rate the quality of evidence of collected outcomes, the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) was used.

RESULTS

Data from 17 studies (2037 patients) were collected. 48.5% (988 of 2037 patients) were women. The mean age of the patients was 52.7 ± 3.9 years, the mean BMI 27.0 ± 1.3 kg/m². The current evidence suggests no difference in functional PROMs (quality of the evidence: high), clinical PROMs (quality of the evidence: high), pain (quality of the evidence: high), quality of life (quality of the evidence: high), physical performance measures (quality of the evidence: moderate), and OA progression (quality of the evidence: moderate).

CONCLUSIONS

The benefits of APM in adults with degenerative and nonobstructive meniscal symptoms are limited. The current evidence reports similarity in the outcome between APM and PT. Further long-term RCTs are required to investigate whether APM and PT produce comparable results using validated and reliable PROMs. Moreover, future RCTs should investigate whether patients who might benefit from APM exist, clarifying proper indications and outcomes. High quality investigations are strongly required to establish the optimal PT regimes.

LEVEL OF EVIDENCE

Level I.

Rehabilitation Variability Following Osteochondral Autograft and Allograft Transplantation of the Knee

OBJECTIVE

The aim of this study is to assess the variability of postoperative rehabilitation protocols used by orthopedic surgery residency programs for osteochondral autograft transplantation (OAT) and osteochondral allograft transplantation (OCA) of the knee.

DESIGN

Online postoperative OAT and OCA rehabilitation protocols from US orthopedic programs and the scientific literature were reviewed. A custom scoring rubric was developed to analyze each protocol for the presence of discrete rehabilitation modalities and the timing of each intervention.

RESULTS

A total of 16 programs (10.3%) from 155 US academic orthopedic programs published online protocols and a total of 35 protocols were analyzed. Twenty-one protocols (88%) recommended immediate postoperative bracing following OAT and 17 protocols (100%) recommended immediate postoperative bracing following OCA. The average time protocols permitted weight-bearing as tolerated (WBAT) was 5.2 weeks (range = 0-8 weeks) following OAT and 6.2 weeks (range = 0-8 weeks) following OCA. There was considerable variation in the inclusion and timing of strength, proprioception, agility, and pivoting exercises. Following OAT, 2 protocols (8%) recommended functional testing as criteria for return to sport at an average time of 12.0 weeks (range = 12-24 weeks). Following OCA, 1 protocol (6%) recommended functional testing as criteria for return to sport at an average time of 12.0 weeks (range = 12-24 weeks).

CONCLUSION

A minority of US academic orthopedic programs publish OAT and OCA rehabilitation protocols online. Among the protocols currently available, there is significant variability in the inclusion of specific rehabilitation components and timing of many modalities. Evidence-based standardization of elements of postoperative rehabilitation may help improve patient care and subsequent outcomes.

Osteochondral Allograft Transplantation of the Lateral Femoral Condyle and Distal Femoral Osteotomy in the Setting of Failed Osteochondritis Dissecans Fixation

Osteochondritis dissecans (OCD) is a pathologic condition, most commonly affecting the knee joint in adolescents and young adults, although pathology can also be found at the elbow and ankle. Lesions to the medial femoral condyle are classically associated with varus alignment, while lesions to the lateral femoral condyle are seen in patients with valgus malalignment. Common risk factors for failed fixation of OCD lesions include unstable lesions to the lateral femoral condyle, screw breakage, older age, and closed physes. The purpose of this technical note is to describe the preoperative planning and step-by-step surgical approach for treatment of failed fixation of an OCD lesion of the posterior aspect of the lateral femoral condyle in young, active patients using an osteochondral allograft, a lateral opening wedge distal femoral osteotomy to correct malalignment, and a tibial tubercle osteotomy to facilitate access to the lesion.

The Influence of Athletes' Age in the Onset of Osteoarthritis: A Systematic Review

PURPOSE

Whether sport participation is a risk factor for osteoarthritis (OA) development or progression is controversial. Mechanical overload, injuries, genetics, and acquired disorders concur to the onset of OA, with high variability between sports and participants. This study investigated the association between participation in specific sports and the risk of developing knee and hip OA in athletes at different ages. We hypothesized that young athletes who are exposed to high levels of physical activities have a greater risk of developing OA.

MATERIALS AND METHODS

This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed, Google scholar, EMABSE, and Web of Science were accessed in October 2021. No time constrains were used for the search. All the published clinical studies reporting data about relationship between physical activity, OA, and age were included.

RESULTS

The Newcastle-Ottawa Scale resulted in a final score ≥7 for all studies, attesting good quality of the methodological assessment. Data from 27,364 patients were retrieved. The mean age was 48.2±16.7 years. In all, 21.8% were women.

CONCLUSIONS

Our systematic review suggests an association between high levels of physical activities and knee and hip OA in men younger than 50 years. People who practice intense physical activity, such as professional athletes or heavy workers, are more prone to develop early-onset OA.

Material-Assisted Strategies for Osteochondral Defect Repair

The osteochondral (OC) unit plays a pivotal role in joint lubrication and in the transmission of constraints to bones during movement. The OC unit does not spontaneously heal; therefore, OC defects are considered to be one of the major risk factors for developing long-term degenerative joint diseases such as osteoarthritis. Yet, there is currently no curative treatment for OC defects, and OC regeneration remains an unmet medical challenge. In this context, a plethora of tissue engineering strategies have been envisioned over the last two decades, such as combining cells, biological molecules, and/or biomaterials, yet with little evidence of successful clinical transfer to date. This striking observation must be put into perspective with the difficulty in comparing studies to identify overall key elements for success. This systematic review aims to provide a deeper insight into the field of material-assisted strategies for OC regeneration, with particular considerations for the therapeutic potential of the different approaches (with or without cells or biological molecules), and current OC regeneration evaluation methods. After a brief description of the biological complexity of the OC unit, the recent literature is thoroughly analyzed, and the major pitfalls, emerging key elements, and new paths to success are identified and discussed.

Marrow Stimulation Has Relatively Inferior Patient-Reported Outcomes in Cartilage Restoration Surgery of the Knee: A Systematic Review and Meta-analysis of Randomized Controlled Trials

BACKGROUND

Multiple cartilage repair techniques are available for chondral defects in the knee. Optimal treatment is controversial.

PURPOSE

To evaluate change from baseline in the 5 Knee injury and Osteoarthritis Outcome Score (KOOS) subscales among different cartilage repair techniques of the knee.

STUDY DESIGN

Systematic review and meta-analysis; Level of evidence, 1A.

METHODS

Medline and Cochrane Central Register of Controlled Trials (CENTRAL) databases were searched for randomized controlled trials with minimum 1 year follow-up reporting change from baseline KOOS (delta KOOS) subscale values. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were followed. A meta-analysis was performed on the following surgery types: microfracture (Mfx); augmented microfracture techniques (Mfx+Augment); and culture-based therapies, including autologous chondrocyte implantation (ACI) and matrix-assisted autologous chondrocyte implantation (MACI). A random-effects metaregression model was used.

RESULTS

A total of 14 randomized trials with a total of 775 patients were included. The KOOS Sport and Recreation (Sport) and KOOS Quality of Life (QOL) were the 2 most responsive subscales after operative intervention. Outcomes from Mfx and Mfx+Augment were not different in any of the 5 KOOS subscales (minimum P > .3). The mean delta KOOS Sport after ACI/MACI was 9.9 points greater than after Mfx (P = .021) and 11.7 points greater than after Mfx+Augment (P = .027). Longer follow-up time correlated with greater delta KOOS Sport (P = .028). Larger body mass index led to greater delta KOOS QOL (P = .045). Larger cartilage defect size correlated with greater delta KOOS Pain and KOOS Activities of Daily Living scores (P = .023 and P = .002, respectively).

CONCLUSION

The KOOS Sport and QOL were the most responsive subscales after cartilage restoration surgery of the knee. Culture-based therapies (ACI/MACI) led to clinically relevant improvements in the KOOS Sport score compared with marrow stimulation and may be a more appropriate treatment in younger and more active individuals. There were no benefits to Mfx+Augment over Mfx alone in any of the KOOS subscales.

The Role of Mesenchymal Stromal Cells in the Management of Knee Chondral Defects

➤

Mesenchymal stromal cells (MSCs) are a subset of progenitor cells that help to promote tissue healing and regeneration through the secretion of various cytokines and growth factors. Although technically pluripotent, MSCs in vivo rarely repair damaged tissue through direct differentiation and engraftment.

➤

Augmentation of traditional marrow stimulation techniques with MSCs has been theorized to improve repair tissue quality and defect fill. Clinical trials evaluating this technique are limited but have shown modest improvements compared with isolated marrow stimulation.

➤

Various scaffolds also have been utilized in combination with MSCs to treat focal chondral defects. Although the techniques described are heterogeneous, many have shown promising early clinical outcomes.

➤

Newer techniques involving 3-dimensional bioprinted scaffolds seeded with MSCs allow for the recreation of complex architecture, more closely resembling articular cartilage. These techniques are evolving and have not yet been studied in human clinical trials.

Tissue Engineering and Cell Therapy for Cartilage Repair: Preclinical Evaluation Methods

A chondral injury is a limiting disease that can affect the quality of life and be an economic burden due to the cost of immediate treatment and loss in work productivity. If left untreated, such an injury may progress to osteoarthritis, a degenerative and debilitating joint disease characterized by pain and functional impairment. Mesenchymal stromal cells (MSCs), which have immune-modulatory properties and the ability to differentiate into chondroblasts and osteoblasts, are a predictable source for the treatment of cartilage injuries. This article presents tools to evaluate cartilage restoration by tissue engineering and cell therapy treatment in a translational and preclinical large animal model. In this controlled experimental study with 14 miniature pigs, a scaffold-free tissue engineering construct (TEC) derived from dental pulp and synovial MSCs for cartilage therapy was tested. Total thickness cartilage defects were performed in both posterior knees. The defect was left empty in one of the knees, and the other received the TEC. The tissue repair was morphologically assessed by magnetic resonance imaging (MRI) using the three-dimensional double echo steady-state (3D-DESS) sequence, and compositional assessment was carried out based on the T2 mapping technique. The osteochondral specimens were fixed for histopathology, decalcified, subjected to standard histological processing, sectioned, and stained with hematoxylin and eosin. The sections stained for immunohistochemical detection of collagen types were digested with pepsin and chondroitinase and incubated with antibodies against them. The mechanical evaluation involved analysis of Young's modulus of the cartilage samples based on the indentation and maximum compression test. In addition, a finite element model was used to simulate and characterize properties of the osteochondral block. At 6 months after surgery, there were no complications with the animals and the MRI, histological, immunohistochemical, and biomechanical evaluations proved to be effective and qualified to differentiate good quality chondral repair from inadequate repair tissue. The proposed methods were feasible and capable to properly evaluate the defect filled with TEC containing stromal cells after 6 months of follow-up in a large animal model for articular cartilage restoration. Impact Statement Articular chondral injuries are prevalent and represent an economic burden due to the cost of treatment. The engineering of cartilage tissue can promote the repair of chondral injuries and is dependent on selecting appropriate cells and biocompatible frameworks. In this article, methods for evaluation of a scaffold-free cell delivery system made from mesenchymal stromal cells were present in a translational study that allows further clinical safety and efficacy trials.

The Arthroscopic Application of Radiofrequency in Treatment of Articular Cartilage Lesions

Articular cartilage lesion is a common disease to be treated by arthroscopic surgery. It will eventually progress to osteoarthritis without proper management, which can affect patients’ work and daily life seriously. Although mechanical debridement and laser have been used clinically for its treatment, due to their respective drawbacks, radiofrequency has drawn increasing attention from clinicians as a new technique with more advantages. However, the safety and efficacy of radiofrequency have also been questioned. In this article, the scope of application of radiofrequency was reviewed following an introduction of its development history and mechanism, and the methods to ensure the safety and effectiveness of radiofrequency through power and temperature control were summarized.

Outcomes Associated With Osteochondral Allograft Transplantation in Dogs

The purpose of this study was to retrospectively characterize outcomes and complications associated with osteochondral allograft transplantation for treating chondral and osteochondral lesions in a group of client-owned dogs with naturally-occurring disease. Records were reviewed for information on signalment, treated joint, underlying pathology (e.g., osteochondritis dissecans; OCD), and type, size, and number of grafts used. Complications were classified as “trivial” if no treatment was provided, “non-surgical” if non-surgical treatment were needed, “minor surgical” if a minor surgical procedure such as pin removal were needed but the graft survived and function was acceptable, or “major” if the graft failed and revision surgery were needed. Outcomes were classified as unacceptable, acceptable, or full function. Thirty-five joints in 33 dogs were treated including nine stifles with lateral femoral condyle (LFC) OCD and 10 stifles with medial femoral condyle (MFC) OCD treated with osteochondral cylinders or “plugs.” There were 16 “complex” procedures of the shoulder, elbow, hip, stifle, and tarsus using custom-cut grafts. In total there were eight trivial complications, one non-surgical complication, two minor surgical complications, and five major complications for a total of 16/35 cases with complications. Accordingly, there were five cases with unacceptable outcomes, all of whom had major complications while the other 30 cases had successful outcomes. Of the 30 cases with successful outcomes, 15 had full function and 15 had acceptable function. Based on these subjective outcome assessments, it appears osteochondral allograft transplantation is a viable treatment option in dogs with focal or complex cartilage defects. However, no conclusions can be made regarding the inferiority or superiority of allograft transplantation in comparison to other treatment options based upon these data.

Semi-quantitative magnetic resonance imaging scoring of the knee detects previous injuries in professional soccer players

PURPOSE

The medical examination ("medical") is an important procedure in professional soccer since it has high economic relevance. In addition to clinical tests, magnetic resonance imaging (MRI) is used to assess joint health. In the present study, the reliability of semiquantitative knee MRI during the "medical" in professional soccer was tested, and its relationship with clinical data and days missed due to knee injury was observed.

METHODS

In this cross-sectional study, between 2012 and 2019, 69 newly assigned players (age 18-35 years) from a professional soccer club underwent MRI (3.0 T) of both knee joints during their "medical". Reported knee injuries and previously missed days due to injury were obtained from player anamnesis and the "transfermarkt.com" database. Based on the established "Whole-Organ Magnetic Resonance Imaging Score" (WORMS), two independent radiologists graded the MRI results. Further evaluation was based on the mean score of both knees.

RESULTS

The mean WORMS for all subjects was 13.9 (median 10.5, range 0-61). Players with previous injuries had significantly higher scores than players without reported injuries (22.1 ± 17.7 vs. 8.9 ± 4.4, p < 0.002). Three outliers (previously undetected injuries) in the group of players without reported injuries were observed (6.7%). The WORMS was significantly correlated with a prior knee injury (r: 0.424, p < 0.0001) and days missed due to injury (r: 0.489, p < 0.001). Age was correlated with the WORMS (r: 0.386, p < 0.001). In a linear regression model, prior injury was the only significant predictor of a high WORMS (p = 0.001). The WORMS was a significant predictor of days missed due to injury (p < 0.0002) and prior injury (sensitivity: 78%, specificity: 91%, p = 0.006). The intraclass correlation coefficient was excellent (0.89).

CONCLUSION

Semiquantitative knee MRI for WORMS determination during the soccer "medical" is a robust and reliable method. Prior injury, even in players without documented trauma, was detected by the WORMS, and previously missed days due to injury were correlated with the semiquantitative MR knee score.

LEVEL OF EVIDENCE

Level III.

The Importance of Staging Arthroscopy for Chondral Defects of the Knee

This study aims to evaluate the role of staging arthroscopy in the diagnosis of knee chondral defects and subsequent surgical planning prior to autologous chondrocyte implantation (ACI), osteochondral allograft transplantation (OCA), and meniscus allograft transplantation (MAT). All patients who underwent staging arthroscopy prior to ACI, OCA, or MAT at our institution from 2005 to 2015 were identified. Medical records were reviewed to document the diagnosis and treatment plan based on symptoms, magnetic resonance imaging (MRI) findings and previous operative records. Operative records of the subsequent staging arthroscopy procedure were reviewed to document the proposed treatment plan after arthroscopy. All changes in treatment plan following staging arthroscopy were recorded. Univariate analyses were performed to identify any significant predictors for likelihood to change. A total of 98 patients were included in our analysis. A change in surgical plan was made following arthroscopy in 36 patients (36.7%). Fourteen patients (14.3%) were found to have additional defects that warranted cartilage restoration surgery. In 15 patients (15.3%), at least one defect that was originally thought to warrant cartilage restoration surgery was found to be amenable to debridement alone. The surgical plan was changed from ACI to OCA in four cases (4.1%) and OCA to ACI in one case (1%). A previously proposed MAT was deemed unwarranted in one case (1%), and a planned meniscal repair was changed to MAT in another (1%). Patient age, sex, and the affected knee compartment were not predictors for a change in surgical plan. Body mass index (BMI) was significantly higher in patients who had a change in surgical plan (29.5 kg/m²) compared with those who did not (26.5 kg/m²). A change in surgical plan was more likely to occur for trochlear lesions (46.4%) compared with other articular surface lesions (p = 0.008). The results of our study indicate that staging arthroscopy is an important step in determining the most appropriate treatment plan for chondral defects and meniscal deficiency, particularly those with trochlear cartilage lesions.

Timing of postoperative weightbearing in the treatment of traumatic chondral injuries of the knee in athletes - A systematic review of current concepts in clinical practice

BACKGROUND

Surgery aims to stimulate healing and enable a safe return to sport in athletes with symptomatic cartilage lesions of the knee. Timing of postoperative weightbearing is crucial, balancing a stimulation of the healing and avoiding reinjury.To explore current concepts of timing to partial and full weightbearing and rate of return to sport in athletes after articular cartilage surgery of the knee.Systematic Review of studies with level of evidence I-III.

METHODS

Four databases (Pubmed, Web of Science, Scopus and Embase) were searched using a predetermined keyword strategy. Two independent reviewers screened results according to inclusion and exclusion criteria. Modified Coleman Methodology Score (mCMS) was used for the quality assessment.

RESULTS

5294 records were found. Data from ten studies was extracted after duplicate removal, title and abstract screening and full-text evaluation. Eight of the ten studies included a detailed rehabilitation protocol, including 336 out of a total athletic population of 401. 62% began partial weightbearing (PWB) 1-2 weeks postoperatively, while 38% began within 3-4 weeks. The studies that had a later PWB all returned to full weightbearing (FWB) within 6-8 weeks. One study with early PWB returned to early FWB, while the other two returned 10-12 weeks postoperatively. "Return to Sport" (RTS) was the most common reported outcome measure, with most studies reporting RTS at 80% or higher.

CONCLUSION

There is no clear evidence that the timing of weightbearing (WB) affects the outcome and return to sport in athletes after surgery for focal full-thickness cartilage lesions of the knee. On the other hand, there seems to be no adverse effects in adopting an early WB strategy, currently defined differently by different authors. Further studies directly comparing the timing of WB for specific surgical procedures in athletes and with relevant control groups is recommended. There is a need for a consensus in regard to more exactly defining "early" vs "late" weightbearing in relation to a universal and precisely defined state of healing.