Outcomes of microfracture for traumatic chondral defects of the knee: average 11-year follow-up

Cartilage regeneration and long term survival in medial OA knee patients treated with HTO and OATS

Background

Osteoarthritis (OA) of the knee, in most instances primarily, affects medial compartment of knee. Combining Osteochondral Autologous Transfer System (OATS) with Medial Open-Wedge High Tibial Osteotomy (MOWHTO) may represent an integrated approach to sustaining long-term knee functionality in OA patients.

Materials and methods

From 2009 to 2016, combined OATS and MOWHTO was performed in 66 knees of 63 patients with medial compartment knee OA. Cartilage regeneration was assessed by 2nd look arthroscopy and Knee function was assessed by knee society scoring (KSS) pre-operatively and post-operatively. The survival rate of MOWHTO plus OATS was assessed. Failure is characterized by the need to convert into total knee replacement.

Results

The KSS knee score (from 48.3 to 90.4) and function score (from 42.6 to 88.7) showed a statistically significant improvement (p-value of <0.0001) at a mean follow-up period of 9.49 years. Second look arthroscopy done at the time of implant removal showed 100 % cartilage regeneration with even hyaline cartilage regeneration in 49 out of 57 knees assessed and partial regeneration in 8 knees. The Kaplan Meier survivorship analysis was 96.7 % at the mean 9.49 years after surgery. Only 2 patients needed TKA conversion in follow-up.

Conclusion

Combining OATs and valgus MOWHTO provides good option to successfully manage patients of OA and varus malalignment. This resulted in significant improvement in knee function, lowering pain intensity, good cartilage regeneration, and a high survivorship rate for 10 years postoperatively.

Is microfracture sufficient for high-tibial osteotomy, or should intra-articular hyaluronic acid and oral glucosamine-chondroitin be used as additional treatments?

BACKGROUND

This study aimed to compare the effects of microfracture (MF) versus intra-articular hyaluronic acid (HA) + oral glucosamine and chondroitin sulfate (GC) in addition to MF in patients with osteoarthritic knees who underwent medial open wedge high tibial osteotomy (MOWHTO) after an average follow-up of five years.

METHODS

The study was designed retrospectively and included patients who underwent MOWHTO due to gonarthrosis, the MF method performed on these patients, and HA + GC treatments applied in addition to MF. Three groups consisting of 79 patients were formed: only HTO (Group 1), HTO + MF (Group 2), and HTO + MF + HA + GC (Group 3). The groups were compared using knee injury and osteoarthritis outcome score (KOOS), visual analog scale (VAS) for pain, and range of motion (ROM). The associations between the degree of correction and function and pain were evaluated. Additionally, the KOOS subparameters were compared between the groups.

RESULTS

There were significant improvements in the postoperative KOOS and VAS scores in all three groups (p < 0.05). However, the ROM did not improve in Group 1. There was no significant difference in the postoperative KOOS, VAS, or ROM values ​​between Groups 2 and 3, but these values ​​were significantly better in Groups 2 and 3 than in Group 1 (p < 0.05). When the degree of correction increased, there were no significant positive changes in the postoperative KOOS or VAS score in Group 1, unlike in the other two groups (p < 0.05). In corrections of ≥ 10°, while there was no significant difference in the postoperative KOOS or VAS score ​​between Groups 2 and 3, these parameters significantly improved in these two groups compared to Group 1 (p < 0.05). Among the KOOS subparameters, pain and activities of daily living scores ​​were greater in Groups 2 and 3 than in Group 1 (p < 0.05).

CONCLUSIONS

In MOWHTO, MF is a sufficient treatment method that improves the patient's clinical condition without requiring additional treatments such as HA and GC.

LEVEL OF EVIDENCE

III, retrospective cohort study.

Collagen hydrogel-driven pyroptosis suppression and combined microfracture technique delay osteoarthritis progression

The pathogenesis of osteoarthritis (OA), a disease causing severe medical burden and joint deformities, remains unclear. Chondrocyte death and osteochondral injury caused are the main pathological changes in OA. Thus, inhibiting chondrocyte death and repairing defective osteochondral are two important challenges in the treatment of OA. In this study, we found morphological changes consistent with cell pyroptosis in OA cartilage tissues. To inhibit chondrocyte pyroptosis and delay the progression of OA, we proposed to use decellularized extracellular matrix (dECM) and gelatin methacrylate (GelMA) to form a composite hydrogel GelMA/dECM. Regarding osteochondral defect repair, our proposed treatment strategy was hydrogel combined with microfracture (MF) surgery. MF established a biological link between the osteochondral defect and the bone-marrow cavity, prompting the recruitment of bone-marrow mesenchymal stem cells (BMSCs) to the osteochondral defect site, and the retained biopeptides in the hydrogel regulate the polarization of the BMSCs into hyaline cartilage, accelerating the repair of the defect. In vitro/vivo experiments and RNA sequencing analyses demonstrated that GelMA/dECM inhibited the occurrence of chondrocyte pyroptosis and delayed OA disease progression. Hydrogel also recruited numerous of BMSCs and contributed to chondrogenic differentiation, accelerating the in situ repair of defective osteochondral combined with MF. Collectively, GelMA/dECM composite hydrogel inhibited cartilage pyroptosis and reduced the pathway of chondrocyte death. Moreover, the hydrogel combined with microfracture technique could accelerate the repair of osteochondral defects. This is a groundbreaking attempt by tissue engineering, cell biology, and clinical medicine.

Mid-term outcomes of microfracture for the treatment of focal, full-thickness cartilage defects isolated to the humeral head

BACKGROUND

While microfracture has been shown to be an effective treatment for chondral lesions in the knee, evidence to support its use for chondral defects in the shoulder is limited to short-term outcomes studies. The purpose of this study is to determine if microfracture provides pain relief and improved shoulder function in patients with isolated focal chondral defects of the humeral head at a minimum 5-year follow-up.

METHODS

Patients who underwent microfracture procedure for isolated focal chondral defects of the humeral head with a minimum follow-up of 5 years between 02/2006 and 08/2016 were included. At minimum 5-year follow-up, pre- and postoperative patient-reported outcome (PRO) measures were collected, including the American Shoulder and Elbow Surgeons (ASES), Single Assessment Numeric Evaluation (SANE), Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH), Short Form-12 (SF-12) Physical Component Summary (PCS), Visual Analog Scale (VAS) for pain, and patient satisfaction level (1 = unsatisfied, 10 = very satisfied). Demographic, injury, and surgical data were retrospectively reviewed. Surgical failure was defined as revision surgery for humeral chondral defects or conversion to arthroplasty. Kaplan-Meier analysis was performed to determine survivorship at 5 years.

RESULTS

A total of 17 patients met inclusion/exclusion criteria. There were 15 men and 2 women with an average age of 51 years (range 36-69) and an average follow-up of 9.4 years (range 5.0-15.8). The median ASES score improved from 62 (range: 22-88) preoperatively to 90 (range: 50-100) postoperatively (P = .011). Median satisfaction was 8 out of 10 (range: 2-10). There was no correlation between patient age or defect size and PROs. Postoperatively, patients reported significant improvements in recreational and sporting activity as well as the ability to sleep on the affected shoulder (P ≤ .05). Three patients failed and required revision surgery. The Kaplan-Meier analysis determined an overall survivorship rate of 80% at 5 years.

CONCLUSION

The presented study illustrates significant improvements for PROs, improved ability to perform recreational and sporting activities, and a survival rate of 80% at a mean of 9.4 years after microfracture for focal chondral humeral head defects.

Arthroscopic Management of Moderate-to-Severe Osteoarthritis of the Knee: A Systematic Review

BACKGROUND

Total knee arthroplasty (TKA) is the procedure of choice for osteoarthritis of the knee (OAK) when conservative treatment fails; however, high rates of dissatisfaction and poor implant longevity dissuade younger patients from TKA. There is a paucity of evidence that report outcomes and clinical effectiveness of arthroscopic knee procedures in patients with end-stage (grade 3-4) OAK. The purpose of this systematic review was to evaluate the efficacy of arthroscopic treatment for patients with moderate-to-severe (grade 3-4) OAK.

METHODS

A systematic review of the literature was performed with the terms "Knee," "Osteoarthritis," and/or "Arthroscopic debridement," "Arthroscopic lavage," "Arthroscopic microfracture," "Arthroscopic chondroplasty," "debridement," "lavage," "chondroplasty," "microfracture," and/or "arthroscopy" in PubMed (MEDLINE), Embase, and the Cochrane Central Register of Controlled Trials (CENTRAL) databases in November 2023 according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Databases were searched for studies that evaluated outcomes (e.g., pain, function, and conversion to TKA) for patients with Kellgren-Lawrence grade 3 to 4 OAK after knee arthroscopy (including debridement, lavage, microfracture, or chondroplasty) at a minimum 6-month follow-up. Percent improvement from preoperative score was the primary outcome measure. Secondary outcome measures included achievement of minimal clinically importance difference and conversion to TKA.

RESULTS

Nine studies (410 knees with grades 3-4 OAK) were included. Arthroscopic debridement and lavage resulted in a 18.8% to 53.1% improvement at short-term follow-up (e.g., 6 months to 3 years) and a 50.0% improvement at long-term follow-up (e.g., 10 years) in knees with grade 3 OAK and a 15.0% to 41.3% improvement at short-term follow-up and a 46.9% improvement at long-term follow-up in knees with grade 4 OAK. Arthroscopic debridement and microfracture resulted in 1.6% to 50.8% improvement at short-term follow-up in knees with grade 3 OAK. No studies included long-term outcomes or evaluated knees with grade 4 OAK after arthroscopic debridement and microfracture. Conversion to TKA after arthroscopic debridement and lavage occurred in 21.9% of patients with grade 3 OAK and in 35.0% of patients with grade 4 OAK at short-term follow-up and in 47.4% of patients with grade 3 OAK and in 76.5% of patients with grade 4 OAK at long-term follow-up. Conversion to TKA after arthroscopic debridement and microfracture occurred in 10.9% of patients with grade 3 and 4 OAK at long-term follow-up.

CONCLUSION

Arthroscopic debridement, lavage, and microfracture can provide short- and long-term symptomatic relief and improvement in function by up to 50.0% in patients with grade 3 to 4 OAK. These procedures may result in fewer patients with grade 3 OAK undergoing TKA compared with patients with grade 4 OAK.

LEVEL OF EVIDENCE

Level IV; systematic review of Level II-IV studies. See Instructions for Authors for a complete description of levels of evidence.

Cartilage Integrity: A Review of Mechanical and Frictional Properties and Repair Approaches in Osteoarthritis

Osteoarthritis (OA) is one of the most common causes of disability around the globe, especially in aging populations. The main symptoms of OA are pain and loss of motion and function of the affected joint. Hyaline cartilage has limited ability for regeneration due to its avascularity, lack of nerve endings, and very slow metabolism. Total joint replacement (TJR) has to date been used as the treatment of end-stage disease. Various joint-sparing alternatives, including conservative and surgical treatment, have been proposed in the literature; however, no treatment to date has been fully successful in restoring hyaline cartilage. The mechanical and frictional properties of the cartilage are of paramount importance in terms of cartilage resistance to continuous loading. OA causes numerous changes in the macro- and microstructure of cartilage, affecting its mechanical properties. Increased friction and reduced load-bearing capability of the cartilage accelerate further degradation of tissue by exerting increased loads on the healthy surrounding tissues. Cartilage repair techniques aim to restore function and reduce pain in the affected joint. Numerous studies have investigated the biological aspects of OA progression and cartilage repair techniques. However, the mechanical properties of cartilage repair techniques are of vital importance and must be addressed too. This review, therefore, addresses the mechanical and frictional properties of articular cartilage and its changes during OA, and it summarizes the mechanical outcomes of cartilage repair techniques.

A bioactive supramolecular and covalent polymer scaffold for cartilage repair in a sheep model

Regeneration of hyaline cartilage in human-sized joints remains a clinical challenge, and it is a critical unmet need that would contribute to longer healthspans. Injectable scaffolds for cartilage repair that integrate both bioactivity and sufficiently robust physical properties to withstand joint stresses offer a promising strategy. We report here on a hybrid biomaterial that combines a bioactive peptide amphiphile supramolecular polymer that specifically binds the chondrogenic cytokine transforming growth factor β-1 (TGFβ-1) and crosslinked hyaluronic acid microgels that drive formation of filament bundles, a hierarchical motif common in natural musculoskeletal tissues. The scaffold is an injectable slurry that generates a porous rubbery material when exposed to calcium ions once placed in cartilage defects. The hybrid material was found to support in vitro chondrogenic differentiation of encapsulated stem cells in response to sustained delivery of TGFβ-1. Using a sheep model, we implanted the scaffold in shallow osteochondral defects and found it can remain localized in mechanically active joints. Evaluation of resected joints showed significantly improved repair of hyaline cartilage in osteochondral defects injected with the scaffold relative to defects injected with the growth factor alone, including implantation in the load-bearing femoral condyle. These results demonstrate the potential of the hybrid biomimetic scaffold as a niche to favor cartilage repair in mechanically active joints using a clinically relevant large-animal model.

Endogenous Tissue Engineering for Chondral and Osteochondral Regeneration: Strategies and Mechanisms

Increasing attention has been paid to the development of effective strategies for articular cartilage (AC) and osteochondral (OC) regeneration due to their limited self-reparative capacities and the shortage of timely and appropriate clinical treatments. Traditional cell-dependent tissue engineering faces various challenges such as restricted cell sources, phenotypic alterations, and immune rejection. In contrast, endogenous tissue engineering represents a promising alternative, leveraging acellular biomaterials to guide endogenous cells to the injury site and stimulate their intrinsic regenerative potential. This review provides a comprehensive overview of recent advancements in endogenous tissue engineering strategies for AC and OC regeneration, with a focus on the tissue engineering triad comprising endogenous stem/progenitor cells (ESPCs), scaffolds, and biomolecules. Multiple types of ESPCs present within the AC and OC microenvironment, including bone marrow-derived mesenchymal stem cells (BMSCs), adipose-derived mesenchymal stem cells (AD-MSCs), synovial membrane-derived mesenchymal stem cells (SM-MSCs), and AC-derived stem/progenitor cells (CSPCs), exhibit the ability to migrate toward injury sites and demonstrate pro-regenerative properties. The fabrication and characteristics of scaffolds in various formats including hydrogels, porous sponges, electrospun fibers, particles, films, multilayer scaffolds, bioceramics, and bioglass, highlighting their suitability for AC and OC repair, are systemically summarized. Furthermore, the review emphasizes the pivotal role of biomolecules in facilitating ESPCs migration, adhesion, chondrogenesis, osteogenesis, as well as regulating inflammation, aging, and hypertrophy-critical processes for endogenous AC and OC regeneration. Insights into the applications of endogenous tissue engineering strategies for in vivo AC and OC regeneration are provided along with a discussion on future perspectives to enhance regenerative outcomes.

Fresh osteochondral allograft transplantation for knee full-thickness articular cartilage lesions using femoral head of living donors: short-term results

BACKGROUND

Fresh osteochondral allograft transplantation is a good treatment option of cartilage defects. However, this treatment option is not available in all countries due to limited graft availability and tissue banks limitations. The purpose of this study is to assess the short term functional and imaging outcomes of fresh osteochondral allograft transplantation in the knee using the femoral head of living donors.

HYPOTHESIS

Fresh osteochondral allografts from the femoral heads of living donors is a valid graft source for management of distal Femur cartilage defects. This technique can improve functional knee scores with good radiological outcomes.

STUDY DESIGN

Prospective case series.

METHODS

Fifteen patients with full thickness cartilage defects of the distal femur underwent osteochondral allograft transplantation from the femoral heads of living donors. Grafts were transplanted by both shell and multiple dowels techniques. The average follow up duration was 18.3 months (range, 12-25 months). Patients were evaluated by Lysholm and International Knee Documentation Committee (IKDC) scores, radiography and MR imaging using Osteochondral Allograft MRI Scoring System (OCAMRISS).

RESULTS

There was a statistically significant improvement (P < 0.001) in both Lysholm and IKDC average scores at 6 months and 12 months postoperative. Postoperative MRI was done at an average 6.8 months (range, 5-11 months) postoperative. The mean total OCAMRISS score was 3.4 (range, 1-7). A second look arthroscopy was done in four patients and showed intact articular cartilage in all three patients.

CONCLUSION

Femoral head of living donors is a valid new source for fresh osteochondral allograft transplantation of knee osteochondral lesions. Short term results showed improvement in clinical assessment scores. Follow up imaging showed graft incorporation and good MRI scores.

Autologous Osteochondral Transfer of the Knee Demonstrates Continued High Rates of Return to Sport and Low Rates of Conversion to Arthroplasty at Long-Term Follow-Up: A Systematic Review

PURPOSE

To perform a systematic review of the literature to evaluate (1) activity level and knee function, (2) reoperation and failure rates, and (3) risk factors for reoperation and failure of autologous osteochondral transfer (AOT) at long-term follow-up.

METHODS

A comprehensive review of the long-term outcomes of AOT was performed. Studies reported on activity-based outcomes (Tegner Activity Scale) and clinical outcomes (Lysholm score and International Knee Documentation Committee score). Reoperation and failure rates as defined by the publishing authors were recorded for each study. Modified Coleman Methodology Scores were calculated to assess study methodological quality.

RESULTS

Twelve studies with a total of 495 patients and an average age of 32.5 years at the time of surgery and a mean follow-up of 15.1 years (range, 10.4-18.0 years) were included. The mean defect size was 3.2 cm2 (range, 1.9-6.9 cm2). The mean duration of symptoms before surgery was 5.1 years. Return to sport rates ranged from 86% to 100%. Conversion to arthroplasty rates ranged from 0% to 16%. The average preoperative International Knee Documentation Committee scores ranged from 32.9 to 36.8, and the average postoperative International Knee Documentation Committee scores at final follow-up ranged from 66.3 to 77.3. The average preoperative Lysholm scores ranged from 44.5 to 56.0 and the average postoperative Lysholm scores ranged from 70.0 to 96.5. The average preoperative Tegner scores ranged from 2.5 to 3.0, and the average postoperative scores ranged from 4.1 to 7.0.

CONCLUSIONS

AOT of the knee resulted in high rates of return to sport with correspondingly low rates of conversion to arthroplasty at long-term follow-up. In addition, AOT demonstrated significant improvements in long-term patient-reported outcomes from baseline.

LEVEL OF EVIDENCE

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

In situ cell condensation-based cartilage tissue engineering via immediately implantable high-density stem cell core and rapidly degradable shell microgels

Formation of chondromimetic human mesenchymal stem cells (hMSCs) condensations typically required in vitro culture in defined environments. In addition, extended in vitro culture in differentiation media over several weeks is usually necessary prior to implantation, which is costly, time consuming and delays clinical treatment. Here, this study reports on immediately implantable core/shell microgels with a high-density hMSC-laden core and rapidly degradable hydrogel shell. The hMSCs in the core formed cell condensates within 12 hours and the oxidized and methacrylated alginate (OMA) hydrogel shells were completely degraded within 3 days, enabling spontaneous and precipitous fusion of adjacent condensed aggregates. By delivering transforming growth factor-β1 (TGF-β1) within the core, the fused condensates were chondrogenically differentiated and formed cartilage microtissues. Importantly, these hMSC-laden core/shell microgels, fabricated without any in vitro culture, were subcutaneously implanted into mice and shown to form cartilage tissue via cellular condensations in the core after 3 weeks. This innovative approach to form cell condensations in situ without in vitro culture that can fuse together with each other and with host tissue and be matured into new tissue with incorporated bioactive signals, allows for immediate implantation and may be a platform strategy for cartilage regeneration and other tissue engineering applications.

Hydrogel-Based Matrix-Associated Autologous Chondrocyte Implantation Shows Greater Substantial Clinical Benefit at 24 Months Follow-Up than Microfracture: A Propensity Score Matched-Pair Analysis

OBJECTIVE

To compare substantial clinical benefit (SCB) of a hydrogel-based, matrix-associated autologous chondrocyte implantation (M-ACI) method versus microfracture (MFx) in the treatment of knee cartilage defects.

DESIGN

Propensity score matched-pair analysis, using the MFx control group of a phase III study as comparator for M-ACI treatment in a single-arm phase III study, resulting in 144 patients in the matched-pair set.

RESULTS

Groups were comparable regarding baseline Knee Injury and Osteoarthritis Outcome Score (KOOS), sex, age, body mass index, symptom duration, smoking status, and previous knee surgeries. Defect sizes in the M-ACI group were significantly larger than in the MFx group (6.4 cm2 vs. 3.7 cm2). Other differences concerned location, number, and etiology of defects that were not considered to influence the interpretation of results. At 24 months, significantly more patients in the M-ACI group achieved SCB in KOOS pain (72.2% vs. 48.6%; P = 0.0108), symptoms (84.7% vs. 61.1%, P = 0.0039), sports/recreation (84.7% vs. 56.9%, P = 0.0008), and quality of life (QoL; 72.2% vs. 44.4%, P = 0.0014). The SCBs for KOOS activities in daily living and International Knee Documentation Committee score were higher for M-ACI but not significantly different from MFx. The SCB rates consistently favored M-ACI from 3 months onward. The highest improvements from baseline at 24 months in patients with SCB were observed for KOOS sports/rec. (M-ACI: 60.8 points, MFx: 55.9 points) and QoL (M-ACI: 58.1, MFx: 57.4).

CONCLUSION

Hydrogel-based M-ACI demonstrated superior SCB in KOOS pain, symptoms, sports/rec., and QoL compared with MFx in patients with knee cartilage defects through 2 years follow-up.

MSX1+PDGFRAlow limb mesenchyme-like cells as an efficient stem cell source for human cartilage regeneration

Degenerative bone disorders have a significant impact on global health, and regeneration of articular cartilage remains a challenge. Existing cell therapies using mesenchymal stromal cells (MSCs) have shown limited efficacy, highlighting the necessity for alternative stem cell sources. Here, we have identified and characterized MSX1+ mesenchymal progenitor cells in the developing limb bud with remarkable osteochondral-regenerative and microenvironment-adaptive capabilities. Single-cell sequencing further revealed the presence of two major cell compositions within the MSX1+ cells, where a distinct PDGFRAlow subset retained the strongest osteochondral competency and could efficiently regenerate articular cartilage in vivo. Furthermore, a strategy was developed to generate MSX1+PDGFRAlow limb mesenchyme-like (LML) cells from human pluripotent stem cells that closely resembled their mouse counterparts, which were bipotential in vitro and could directly regenerate damaged cartilage in a mouse injury model. Together, our results indicated that MSX1+PDGFRAlow LML cells might be a prominent stem cell source for human cartilage regeneration.

Intra-articular injection of ascorbic acid enhances microfracture-mediated cartilage repair

Previous studies have confirmed that ascorbic acid (AA) can promote cartilage repair and improve cartilage differentiation in bone marrow mesenchymal stem cells. However, the use of microfracture (MFX) combined with AA to repair cartilage damage has not been studied. This study established a rabbit animal model and treated cartilage injury with different concentrations of AA combined with MFX. Macroscopic observations, histological analysis, immunohistochemical analysis and reverse transcription quantitative polymerase chain reaction analysis of TGF-β, AKT/Nrf2, and VEGF mRNA expression were performed. The results showed that intra-articular injection of AA had a positive effect on cartilage repair mediated by microfractures. Moreover, 10 mg/ml AA was the most effective at promoting cartilage repair mediated by microfractures. Intra-articular injection of AA promoted the synthesis of type II collagen and the formation of glycosaminoglycans by downregulating the mRNA expression of TGF-β and VEGF. In summary, this study confirmed that AA could promote cartilage repair after MFX surgery.

Trends in Meniscus-Related Publications in PubMed Since 1928: A Bibliometric Study

Background

As information on the meniscus accumulates in PubMed, it is possible to evaluate the trends in research on the topic over time.

Purpose

To evaluate the major trends in meniscus-related publications in PubMed from the earliest publication to the present day.

Study Design

Cross-sectional study.

Methods

PubMed was searched on January 3, 2023, using the search strategy "menisc *"[All Fields] AND ("knee"[MeSH Terms] OR "knee"[All Fields] OR "knee joint"[MeSH Terms] OR ("knee"[All Fields] AND "joint"[All Fields]) OR "knee joint"[All Fields]) AND 1900/01/01:2022/12/31[Date - Publication]. This retrieved 15,569 human and animal studies. We determined the top 10 meniscus-related publications in terms of overall citations and citations per year, as well as the top 10 authors, journals, countries, and institutions of cited publications on the meniscus. In addition, we performed word-cloud analyses based on meniscus-related terms from different periods (before 1981, before 2000, after 2005, and in the past 5 years [2018-2022]), including the year of first appearance and the number of publications featured.

Results

Since the first recorded publication on the meniscus in 1928, there was a steady growth in the number of articles until 2005, when there was an upsurge in publications from 254 in 2005 to 955 in 2022. Noyes was the author with the most citations (n = 3314), and a 2006 study by Caplan and Dennis had the most citations per year (n = 125). Arthroscopy published the most articles on the meniscus with 1118, whereas the Journal of Cellular Biochemistry had the most citations per article with 125.69. The most published countries and institutes were the United States and the Hospital for Special Surgery, respectively. Word-cloud analysis of article titles showed that "meniscectomy" had become less prominent, and "root,""ramp,""transplantation," and "slope" had become more prominent.

Conclusion

There has been an upsurge in publications on the meniscus since 2005, with word-cloud analysis indicating shifting interests in meniscus-related research.

Advanced Therapeutic Medicinal Products in Bone and Cartilage Defects

The number of patients with functional loss of bone and cartilage tissue has shown an increasing trend. Insufficient or inappropriate conventional treatments applied for trauma, orthopedic diseases, or other bone and cartilage-related disorders can lead to bone and cartilage damage. This represents a worldwide public health issue and a significant economic burden. Advanced therapeutic medicinal products (ATMPs) proposed promising alternative therapeutic modalities by application of cell-based and tissue engineering approaches. Recently, several ATMPs have been developed to promote bone and cartilage tissue regeneration. Fifteen ATMPs, two related to bone and 13 related to cartilage, have received regulatory approval and marketing authorization. However, four ATMPs were withdrawn from the market for various reasons. However, ATMPs that are still on the market have demonstrated positive results, their broad application faced limitations. The development and standardization of methodologies will be a major challenge in the coming decades. Currently, the number of ATMPs in clinical trials using mesenchymal stromal cells or chondrocytes indicates a growing recognition that current ATMPs can be improved. Research on bone and cartilage tissue regeneration continues to expand. Cell-based therapies are likely to be clinically supported by the new ATMPs, innovative fabrication processes, and enhanced surgical approaches. In this study, we highlighted the available ATMPs that have been used in bone and cartilage defects and discussed their advantages and disadvantages in clinical applications.

Bilayer osteochondral graft in rabbit xenogeneic transplantation model comprising sintered 3D-printed bioceramic and human adipose-derived stem cells laden biohydrogel

Reconstruction of severe osteochondral defects in articular cartilage and subchondral trabecular bone remains a challenging problem. The well-integrated bilayer osteochondral graft design expects to be guided the chondrogenic and osteogenic differentiation for stem cells and provides a promising solution for osteochondral tissue repair in this study. The subchondral bone scaffold approach is based on the developed finer and denser 3D β-tricalcium phosphate (β-TCP) bioceramic scaffold process, which is made using a digital light processing (DLP) technology and the novel photocurable negative thermo-responsive (NTR) bioceramic slurry. Then, the concave-top disc sintered 3D-printed bioceramic incorporates the human adipose-derived stem cells (hADSCs) laden photo-cured hybrid biohydrogel (HG + 0.5AFnSi) comprised of hyaluronic acid methacryloyl (HAMA), gelatin methacryloyl (GelMA), and 0.5% (w/v) acrylate-functionalized nano-silica (AFnSi) crosslinker. The 3D β-TCP bioceramic compartment is used to provide essential mechanical support for cartilage regeneration in the long term and slow biodegradation. However, the apparent density and compressive strength of the 3D β-TCP bioceramics can be obtained for ~ 94.8% theoretical density and 11.38 ± 1.72 MPa, respectively. In addition, the in vivo results demonstrated that the hADSC + HG + 0.5AFnSi/3D β-TCP of the bilayer osteochondral graft showed a much better osteochondral defect repair outcome in a rabbit model. The other word, the subchondral bone scaffold of 3D β-TCP bioceramic could accelerate the bone formation and integration with the adjacent host cancellous tissue at 12 weeks after surgery. And then, a thicker cartilage layer with a smooth surface and uniformly aligned chondrocytes were observed by providing enough steady mechanical support of the 3D β-TCP bioceramic scaffold.

Microfracture- and Xeno-Matrix-Induced Chondrogenesis for Treatment of Focal Traumatic Cartilage Defects of the Knee: Age-Based Mid-Term Results

The aim of this study was to investigate clinical and instrumental outcomes of the autologous matrix-induced chondrogenesis (AMIC) technique for the treatment of isolated traumatic condyle and femoropatellar cartilage lesions. A total of 25 patients (12 males, 13 females, mean age 47.3 years) treated between 2018 and 2021 were retrospectively reviewed and subdivided into two groups based on age (Group A, age < 45 years; Group B, age > 45 years). A clinical evaluation was performed using the International Knee Documentation Committee (IKDC), Lysholm score and Visual Analogue Score (VAS). Cartilage regeneration was evaluated via magnetic resonance (1.5 Tesla) and classified according to a Magnetic resonance Observation of CArtilage Repair Tissue (MOCART) scoring system. At a minimum follow-up of 2 years, Group A patients obtained greater instrumental results in comparison to group B: in fact, the MOCART score was statistically significantly correlated with IKDC (r = 0.223) (p < 0.001) exclusively in group A. Nevertheless, a significant improvement in clinical functionality was shown in Group B (p < 0.001), demonstrating that this technique is safe, reproducible and capable of offering satisfactory clinical results regardless of age.

Cartilage Tissue Engineering in Practice: Preclinical Trials, Clinical Applications, and Prospects

Articular cartilage defects significantly compromise the quality of life in the global population. Although many strategies are needed to repair articular cartilage, including microfracture, autologous osteochondral transplantation, and osteochondral allograft, the therapeutic effects remain suboptimal. In recent years, with the development of cartilage tissue engineering, scientists have continuously improved the formulations of therapeutic cells, biomaterial-based scaffolds, and biological factors, which have opened new avenues for better therapeutics of cartilage lesions. This review focuses on advances in cartilage tissue engineering, particularly in preclinical trials and clinical applications, prospects, and challenges.

O-alg-THAM/gel hydrogels functionalized with engineered microspheres based on mesenchymal stem cell secretion recruit endogenous stem cells for cartilage repair

Lacking self-repair abilities, injuries to articular cartilage can lead to cartilage degeneration and ultimately result in osteoarthritis. Tissue engineering based on functional bioactive scaffolds are emerging as promising approaches for articular cartilage regeneration and repair. Although the use of cell-laden scaffolds prior to implantation can regenerate and repair cartilage lesions to some extent, these approaches are still restricted by limited cell sources, excessive costs, risks of disease transmission and complex manufacturing practices. Acellular approaches through the recruitment of endogenous cells offer great promise for in situ articular cartilage regeneration. In this study, we propose an endogenous stem cell recruitment strategy for cartilage repair. Based on an injectable, adhesive and self-healable o-alg-THAM/gel hydrogel system as scaffolds and a biophysio-enhanced bioactive microspheres engineered based on hBMSCs secretion during chondrogenic differentiation as bioactive supplement, the as proposed functional material effectively and specifically recruit endogenous stem cells for cartilage repair, providing new insights into in situ articular cartilage regeneration.

Histomorphological Investigation of Microfracture Location in a Rabbit Osteochondral Defect Model

BACKGROUND

Microfracture is the most common treatment for cartilage defects of the knee. In microfracture surgery, holes are randomly drilled into the subchondral bone. The effect of the hole's location on its interaction with the cartilage defect site and its influence on the healing process is currently uncertain.

PURPOSE

To investigate the effects of different microfracture locations on healing in a rabbit knee osteochondral defect model.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 29 adult New Zealand White rabbits were divided into 5 groups. In the healthy cartilage control group (n = 5), no surgical procedure was performed. Cylindrical full-thickness cartilage defects (5 × 3 mm) were created in the patellar groove of the remaining 24 rabbits. In the defect control group (n = 6), only the defect was created. A microfracture was performed at the 12-o'clock position (group peripheral single; n = 6), centrally (group central; n = 6), and at the 12- and 6-o'clock positions (group peripheral double; n = 6) of the defect. The animals were sacrificed after 8 weeks. Cartilage healing was evaluated by International Cartilage Regeneration & Joint Preservation Society (ICRS) score, modified O'Driscoll score, immunohistochemical analysis (type 1 collagen, type 2 collagen, and aggrecan), and scanning electron microscopy analysis.

RESULTS

In group peripheral double, better cartilage healing was observed in all parameters compared with the other groups (P < .05). Group peripheral double had the greatest amount of filling, with 79% of the defect area filled with fibrocartilage repair tissue. Group peripheral single demonstrated filling of 73% of the defect area, group central 56%, and the defect control group 45%. The ICRS score was significantly higher in group peripheral single compared with group central and the defect control group. Type 2 collagen and aggrecan immunoreactivity were significantly stronger in group central than group peripheral single and the defect control group (P < .05).

CONCLUSION

Microfracture performed at the peripheral margin of the defect had better filling characteristics in a rabbit model. This study suggests that interaction of pluripotent cells released from the microfracture site with the intact cartilage may enhance the quality of the repair tissue.

CLINICAL RELEVANCE

The location of microfracture holes in relation to the peripheral border of the osteochondral defect (to the intact cartilage) is important in both the quality and the quantity of the newly formed repair tissue.

Surgical Management of Failed Articular Cartilage Surgery in the Knee

Failure rates of cartilage restoration surgery range from 14% to 43%. When failure of prior cartilage restoration surgery is suspected, a thorough clinical workup should be performed to assess the timing and duration of symptoms. Attention should be paid to patient risk factors such as age, body mass index, and smoking status. Concomitant pathology such as malalignment, ligament insufficiency, and meniscus status must be evaluated before revision surgery. As outlined in our treatment algorithm, the size/location of the lesion and the type of primary procedure will guide planning for revision procedures. [Orthopedics. 2023;46(5):262-272.].

Comparison of Hydrogel-Based Autologous Chondrocyte Implantation Versus Microfracture: A Propensity Score Matched-Pair Analysis

Background

Few studies exist for large defects comparing matrix-associated autologous chondrocyte implantation (M-ACI) with other cartilage repair methods due to the limited availability of suitable comparator treatments.

Purpose

To compare the clinical efficacy of a novel hydrogel-based M-ACI method (NOVOCART Inject plus) versus microfracture (MFx) in patients with knee cartilage defects.

Study Design

Cohort study; Level of evidence, 3.

Methods

Propensity score matched-pair analysis was used to compare the 24-month outcomes between the M-ACI treatment group from a previous single-arm phase 3 study and the MFx control group from another phase 3 study. Patients were matched based on preoperative Knee injury and Osteoarthritis Outcomes Score (KOOS), symptom duration, previous knee surgeries, age, and sex, resulting in 144 patients in the matched-pair set (72 patients per group). The primary endpoint was the change in least-squares means (ΔLSmeans) for the KOOS from baseline to the 24-month assessment.

Results

Defect sizes in the M-ACI group were significantly larger than in the MFx group (6.4 versus 3.7 cm2). Other differences included defect location (no patellar or tibial defects in the MFx group), number of defects (33.3% with 2 defects in the M-ACI group versus 9.7% in the MFx group), and defect cause (more patients with degenerative lesions in the M-ACI group). The M-ACI group had higher posttreatment KOOS (M-ACI versus MFX: 81.8 ± 16.8 versus 73.0 ± 20.6 points) and KOOS ΔLSmeans from baseline to 24 months posttreatment (M-ACI versus MFX: 36.9 versus 26.9 points). Treatment contrasts in KOOS ΔLSmeans from baseline indicated statistical significance in favor of M-ACI from 3 to 24 months posttreatment (P = .0026). Significant and clinically meaningful differences in favor of M-ACI at 24 months were also found regarding International Knee Documentation Committee (IKDC) score ΔLSmeans from baseline (37.8 versus 30.4 points; P = .0334), KOOS responder rates at 24 months (≥10-point improvement from baseline; 94.4% versus 65.3%; P < .0001), IKDC responder rates at 24 months (>20.5-point improvement from baseline; 83.3% versus 61.1%, P = .0126) and MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) score in a subgroup of patients (LS means, 86.9 versus 69.1; P = .0096).

Conclusion

In this exploratory analysis, M-ACI using an in situ crosslinked hydrogel demonstrated superior clinical and structural (MOCART) 24-month outcomes compared with MFx in patients with knee cartilage defects.

Fabricating the cartilage: recent achievements

This review aims to describe the most recent achievements and provide an insight into cartilage engineering and strategies to restore the cartilage defects. Here, we discuss cell types, biomaterials, and biochemical factors applied to form cartilage tissue equivalents and update the status of fabrication techniques, which are used at all stages of engineering the cartilage. The actualized concept to improve the cartilage tissue restoration is based on applying personalized products fabricated using a full cycle platform: a bioprinter, a bioink consisted of ECM-embedded autologous cell aggregates, and a bioreactor. Moreover, in situ platforms can help to skip some steps and enable adjusting the newly formed tissue in the place during the operation. Only some achievements described have passed first stages of clinical translation; nevertheless, the number of their preclinical and clinical trials is expected to grow in the nearest future.

Small-Molecule Loaded Biomimetic Biphasic Scaffold for Osteochondral Regeneration: An In Vitro and In Vivo Study

Osteoarthritis is a prevalent musculoskeletal disorder in the elderly, which leads to high rates of morbidity. Mesenchymal stem cells (MSCs) are a promising approach to promote tissue regeneration in the absence of effective long-term treatments. Small molecules are relatively inexpensive and can selectively alter stem cell behavior during their differentiation, making them an attractive option for clinical applications. In this study, we developed an extracellular matrix (ECM)-based biphasic scaffold (BPS) loaded with two small-molecule drugs, kartogenin (KGN) and metformin (MET). This cell-free biomimetic biphasic scaffold consists of a bone (gelatin/hydroxyapatite scaffold embedded with metformin [GHSM]) and cartilage (nano-gelatin fiber embedded with kartogenin [NGFK]) layer designed to stimulate osteochondral regeneration. Extracellular matrix (ECM)-based biomimetic scaffolds can promote native cell recruitment, infiltration, and differentiation even in the absence of additional growth factors. The biphasic scaffold (BPS) showed excellent biocompatibility in vitro, with mesenchymal stem cells (MSCs) adhering, proliferating, and differentiated on the biomimetic biphasic scaffolds (GHSM and NGFK layers). The biphasic scaffolds upregulated both osteogenic and chondrogenic gene expression, sulfated glycosaminoglycan (sGAG), osteo- and chondrogenic biomarker, and relative mRNA gene expression. In an in vivo rat model, histo-morphological staining showed effective regeneration of osteochondral defects. This novel BPS has the potential to enhance both subchondral bone repair and cartilage regeneration, demonstrating excellent effects on cell homing and the recruitment of endogenous stem cells.

Dual-tissue transplantation versus osteochondral autograft transplantation in the treatment of osteochondral defects: a porcine model study

BACKGROUND

Osteochondral injury is a common sports injury, and hyaline cartilage does not regenerate spontaneously when injured. However, there is currently no gold standard for treating osteochondral defects. Osteochondral autograft transplantation (OAT) is widely used in clinical practice and is best used to treat small osteochondral lesions in the knee that are < 2 cm² in size. Autologous dual-tissue transplantation (ADTT) is a promising method with wider indications for osteochondral injuries; however, ADTT has not been evaluated in many studies. This study aimed to compare the radiographic and histological results of ADTT and OAT for treating osteochondral defects in a porcine model.

METHODS

Osteochondral defects were made in the bilateral medial condyles of the knees of 12 Dian-nan small-ear pigs. The 24 knees were divided into the ADTT group (n = 8), OAT group (n = 8), and empty control group (n = 8). At 2 and 4 months postoperatively, the knees underwent gross evaluation based on the International Cartilage Repair Society (ICRS) score, radiographic assessment based on CT findings and the magnetic resonance observation of cartilage repair tissue (MOCART) score, and histological evaluation based on the O'Driscoll histological score of the repair tissue.

RESULTS

At 2 months postoperatively, the ICRS score, CT evaluation, MOCART score, and O'Driscoll histological score were significantly better in the OAT group than the ADTT group (all P < 0.05). At 4 months postoperatively, the ICRS score, CT evaluation, MOCART score, and O'Driscoll histological score tended to be better in the OAT group than the ADTT group, but these differences did not reach statistical significance (all P > 0.05).

CONCLUSIONS

In a porcine model, ADTT and OAT are both effective treatments for osteochondral defects in weight bearing areas. ADTT may be useful as an alternative procedure to OAT for treating osteochondral defects.

Recent development in multizonal scaffolds for osteochondral regeneration

Osteochondral (OC) repair is an extremely challenging topic due to the complex biphasic structure and poor intrinsic regenerative capability of natural osteochondral tissue. In contrast to the current surgical approaches which yield only short-term relief of symptoms, tissue engineering strategy has been shown more promising outcomes in treating OC defects since its emergence in the 1990s. In particular, the use of multizonal scaffolds (MZSs) that mimic the gradient transitions, from cartilage surface to the subchondral bone with either continuous or discontinuous compositions, structures, and properties of natural OC tissue, has been gaining momentum in recent years. Scrutinizing the latest developments in the field, this review offers a comprehensive summary of recent advances, current hurdles, and future perspectives of OC repair, particularly the use of MZSs including bilayered, trilayered, multilayered, and gradient scaffolds, by bringing together onerous demands of architecture designs, material selections, manufacturing techniques as well as the choices of growth factors and cells, each of which possesses its unique challenges and opportunities.

Arthroscopic Treatment of Femoral Condyle Chondral Lesions: Microfracture Versus Liquid Bioscaffold

Purpose

This study aims to compare the microfracture (MF) technique with the bioscaffold solution application (BST-CarGel) in treating femoral chondral lesions.

Methods

Thirty-eight patients ages 18-45 with isolated single femoral condyle full-thickness (ICRS grade 3-4) chondral lesions were included in the study. Patients were divided into two groups as MF applied (Group I = 21) and bioscaffold combined with MF (Group II = 17). The visual analog scale (VAS), Western-Ontario, and McMaster Osteoarthritis Index (WOMAC) were used in clinical evaluation. The location, size, and depth of lesions were evaluated with preoperative magnetic resonance imaging (MRI). Magnetic resonance observation of cartilage repair tissue (MOCART) score was used for postoperative evaluation.

Results

The mean age was 32.5 (range 19-44) years. Mean follow-up was 14.9 months (range 12-24). Lesion size was 3 cm2 in group I and 2.9 cm2 in group II. There were no differences between groups regarding demographic characteristics but BMI (Body Mass Index) was lower in group II which was significant. The duration of surgery was longer in group II (p < 0.001). Postoperative statistical significant improvements were found in WOMAC and VAS scores in groups, but there was no statistical difference. Although there was no significant radiological difference in the group II according to the MOCART score, higher scores were obtained compared to group I.

Conclusion

No difference was found, clinical and radiological, in terms of short-term outcomes. MF is a method to be applied as a primary treatment with its cost-effective, simple and short surgery technique, and effective clinical results up to 4 cm2.

Level of Evidence

Level III: retrospective comparative study.

Individualized metal implants for focal cartilage lesions in the knee can be cost-effective: A simulation on 47-year-old in a Swedish setting

OBJECTIVES

In the aging population, the knee is the joint most commonly causing impaired function and incapacity. While definite treatment by prosthetic replacement is often performed late, symptomatic knee cartilage lesions cause much suffering also in younger ages. Early intervention could, therefore, be instituted at an early stage to the benefit of both patients and society. Small, metal surface, resurfacing implants have been tested with promising results. A system that features patient-specific implants and surgical instruments shows good clinical results and favorable survival rates. This study aims to assess the cost utility of this metal device compared with microfracture (MFX), being the standard procedure in Sweden.

METHODS

We constructed a simulation model in Excel. In the model, a cohort of 47-year-old patients (which is the mean age of patients treated with the metal implant) with symptomatic knee cartilage lesions received either MFX or metal implantation. Outcomes for the cohort were simulated over 40 years, such as in a previously published model based on MFX, and sensitivity analyses (deterministic and probabilistic) of the results were undertaken. Data on transition probabilities, costs, and quality of life were taken from clinical data, published literature, and official price lists. Only direct medical costs were included.

RESULTS

Results from the analysis showed that the metal device is a cost-effective treatment strategy compared with MFX. The incremental cost-effectiveness ratio (ICER) reached acceptable levels at ∼5 years postoperatively. Over the full-time horizon of 40 years, the metal device was cost saving with concomitant gains in quality-adjusted life years (QALYs), translating to a dominant treatment strategy. Results were robust according to sensitivity analysis with the initial success rate of up to three years for both metal and MFX having the largest impact.

CONCLUSIONS

A metal implant may be a cost-effective treatment alternative for patients in their 40's when compared to MFX in a Swedish setting.

LEVEL OF EVIDENCE

5 [1].

Changes in the Subchondral Bone Affect Pain in the Natural Course of Traumatic Articular Cartilage Defects

OBJECTIVE

Articular cartilage defect causes joint pain and finally progresses to osteoarthritis. Although the subchondral bone condition affects clinical outcomes of cartilage defects, the natural course of changes in subchondral bone and associated pain in full-thickness cartilage defects remain unknown. Therefore, we investigated the natural course of histological changes in subchondral bone and joint pain in cartilage defects using a rat model.

DESIGN

Full-thickness cartilage defects were created at the medial femoral condyle of 10-week-old male Sprague-Dawley rats. Rats were sacrificed at 3, 7, 14, 28, and 56 days postoperatively, and histological including immunohistochemistry and tartrate-resistant acid phosphatase (TRAP) staining and micro-computed tomography (μCT) analyses of their knees were performed. Pain was evaluated using behavioral analysis and immunofluorescence staining of the dorsal root ganglion (DRG).

RESULTS

The contour of the subchondral bone plate was maintained until day 3, but it was absorbed just under the cartilage defect from day 7 to 14. Starting on day 28, sclerotic changes surrounding the bone absorption area were detected. In the subchondral bone, the number of TRAP-positive cells peaked on day 14. Osteocalcin-positive cells were observed at 7 days, and their number gradually increased till day 56. Behavioral analysis showed that the total distance and the number of getting up by hind legs decreased on day 14. The number of calcitonin gene-related peptide-positive fibers in the DRG increased and was the highest on day 14.

CONCLUSIONS

The subchondral bone condition under cartilage defects dynamically changes from bone resorption to sclerosis and is related to pain level.

Hyalofast Cartilage Repair Surgery with a Full Load-Bearing Rehabilitation Program One Day after Operation Reduces the Time for Professional Athletes to Return to Play

Background and Objectives: This study evaluated the effectiveness of Hyalofast cartilage repair surgery with an early, full load-bearing rehabilitation program one day after the operation for reducing the time needed for professional athletes to return to play. Materials and Methods: This prospective study included 49 patients aged between 19 and 38 years who had undergone surgical reconstruction of cartilage using the microfracture technique combined with a Hyalofast scaffold. All patients were active professional athletes. Early rehabilitation was implemented from the first postoperative day, fully loading the operated limb. A clinical evaluation was based on the KOOS and SF-36 questionnaires used during subsequent follow-up visits. All patients underwent magnetic resonance imaging (MRI) to evaluate the effect of the surgery after one year. Results: The clinical results demonstrated a statistically significant improvement in the number of complaints about pain and in the quality of life of the patients, measured in all of the applied scales, with comparisons made between six months or one year post-surgery and pre-surgery. Importantly for athletes, the parameter related to sports and recreation improved from 14 ± 11.1 to 95 ± 7.7 6 months after surgery and to 99.8 ± 1.8 one year after surgery. The overall quality of life score improved from 30 ± 18 to 88 ± 8.8 one year after surgery. Conclusions: These results show that this approach significantly shortened the time needed for the athletes to return to sports at the same level as before the surgery (athletes returned to sports in approximately 2.5-3 months). The mean follow-up time was 19.75 months. This technique can be considered a viable option for the treatment of cartilage injuries in professional athletes, allowing them to return to play more quickly in a safe and healthy way.

Autologous Collagen-Induced Chondrogenesis: From Bench to Clinical Development

Microfracture is a common technique that uses bone marrow components to stimulate cartilage regeneration. However, the clinical results of microfracture range from poor to good. To enhance cartilage healing, several reinforcing techniques have been developed, including porcine-derived collagen scaffold, hyaluronic acid, and chitosan. Autologous collagen-induced chondrogenesis (ACIC) is a single-step surgical technique for cartilage regeneration that combines gel-type atelocollagen scaffolding with microfracture. Even though ACIC is a relatively new technique, literature show excellent clinical results. In addition, all procedures of ACIC are performed arthroscopically, which is increasing in preference among surgeons and patients. The ACIC technique also is called the Shetty–Kim technique because it was developed from the works of A.A. Shetty and S.J. Kim. This is an up-to-date review of the history of ACIC.

Femoral condyle resurfacing using an inlay metal implant: low revision rate of 266 patients in a 5-10 years follow-up

PURPOSE

To assess the clinical outcome and survival of an inlay resurfacing prosthesis for focal femoral condyle chondral and osteochondral defects.

METHODS

Two hundred sixty-six patients (mean age, 38.25 years; range 25-56 years) with symptomatic femoral condyle chondral and osteochondral defects were reviewed. The mean follow-up period was 7.3 years (range 5-10 years). The medial femoral condyle was involved in 229 and the lateral condyle in 37 patients. Previous cartilage surgery was done in 235 patients. All patients were treated with focal femoral condyle resurfacing with the HemiCAP^® device. The preoperative and the last follow-up values of the Knee Injury and Osteoarthritis Outcome Score (KOOS), Oxford Knee Score (OKS), 36-item Short Form Survey (SF-36) and Visual Analogue Scale (VAS) were examined. Complications, reoperation rate and survival were analyzed.

RESULTS

At the last follow-up, all clinical score values showed significant improvement as compared with the corresponding preoperative values (p < 0.001). Age presented a negative correlation with KOOS (p = 0.03) and SF-36 improvement (p = 0.014). Kellgren-Lawrence grade influenced OKS (p = 0.036). BMI, gender, side, medial or lateral condyle and size did not affect the outcome. Patients who had previous biological cartilage procedures demonstrated better clinical improvement in comparison with those that did not have prior surgery (p < 0.05). Survival was 96.2% at 10 years, using as endpoint implant revision or/and progression of osteoarthritis. The cumulative hazard for any-reason reoperation was 12.0%.

CONCLUSIONS

Femoral condyle resurfacing using the HemiCAP^® device is an effective treatment option to address focal chondral and osteochondral defects. It can be successfully used either as a primary procedure or after prior biological cartilage reconstruction. Subjective clinical outcomes are expected to be good to excellent in mid- to long term, while reoperation and revision rates are low. Progression of osteoarthritis is the most common mode of failure; thus, patient selection is very important.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Prognostic Factors for the Clinical Outcome after Microfracture Treatment of Chondral and Osteochondral Defects in the Knee Joint: A Systematic Review

OBJECTIVE

The objective of this study is to establish which patient and lesion characteristics are related to the clinical outcome after microfracture of cartilage defects in the knee.

STUDY DESIGN

Systematic review.

METHODS

After preregistration, PubMed, Embase, and Cochrane were searched for studies that analyzed prognostic factors for the outcome of microfracture treatment in the knee. The criteria for inclusion were outcome measured using Patient-Reported Outcome Measures (PROMs), a clinical study with ≥10 participants receiving microfracture, and a minimal follow-up period of 1 year.

RESULTS

For none of the investigated prognostic factors, effect size reporting was sufficiently homogeneous to conduct a meta-analysis. However, a majority of the included studies identified higher age, larger lesion size, longer preoperative symptom duration, and previous surgery on the ipsilateral knee, especially meniscectomy and anterior cruciate ligament reconstruction, as factors that are reported to be correlated to a less favorable outcome. A lesion location that does not include the trochlea or the patellofemoral joint and is not weightbearing, a nondegenerative mechanism of injury, and a single lesion were reported as factors that predict a favorable outcome. As to gender, body mass index, preoperative activity level, smoking, and concomitant knee surgery, the included articles were inconclusive or no effect was reported.

CONCLUSIONS

Several factors correlated with the clinical result after microfracture treatment. However, the information on the effect sizes of the influence on clinical outcome is incomplete due to poor reporting. Large-scale registries or pooling of homogeneous, well-reported data is needed to work toward prognostic models. That would be an important step toward personalized treatment.

Hopes and opportunities of stem cells from human exfoliated deciduous teeth (SHED) in cartilage tissue regeneration

Cartilage lesions are common conditions, affecting elderly and non-athletic populations. Despite recent advances, cartilage regeneration remains a major challenge today. The absence of an inflammatory response following damage and the inability of stem cells to penetrate into the healing site due to the absence of blood and lymph vessels are assumed to hinder joint repair. Stem cell-based regeneration and tissue engineering have opened new horizons for treatment. With advances in biological sciences, especially stem cell research, the function of various growth factors in the regulation of cell proliferation and differentiation has been established. Mesenchymal stem cells (MSCs) isolated from different tissues have been shown to increase into therapeutically relevant cell numbers and differentiate into mature chondrocytes. As MSCs can differentiate and become engrafted inside the host, they are considered suitable candidates for cartilage regeneration. Stem cells from human exfoliated deciduous teeth (SHED) provide a novel and non-invasive source of MSCs. Due to their simple isolation, chondrogenic differentiation potential, and minimal immunogenicity, they can be an interesting option for cartilage regeneration. Recent studies have reported that SHED-derived secretome contains biomolecules and compounds that efficiently promote regeneration in damaged tissues, including cartilage. Overall, this review highlighted the advances and challenges of cartilage regeneration using stem cell-based therapies by focusing on SHED.

Selective Formation of Osteogenic and Vasculogenic Tissues for Cartilage Regeneration

Tissue-engineered periosteum substitutes (TEPSs) incorporating hierarchical architecture with osteoprogenitor and vascular niches are drawing much attention as a promising tool to support functional cells in defined zones and nourish the cortical bone. Current TEPSs usually lack technologies to closely observe cell performance, especially at the cell contact interface between distinct compartments containing defined biological configurations and functions. Here, an electrodeposition strategy is reported, which enables the selective formation of TEPSs with osteoprogenitor and vascular niches in a multiphasic scaffold in combination with different human cell types for cartilage regeneration in an in vivo osteochondral defect model. Human umbilical vein endothelial cells (HUVECs), dermal fibroblasts (HDFs), and bone marrow mesenchymal stem cells (hMSCs) are used to mirror both the vascular and osteogenic niches, respectively. It is observed that the intrinsic viscoelastic nature of the porous solid matrix is essential to successfully induce angiogenesis. Coculture of hMSCs with functional cells (HUVECs/HDFs) in TEPSs also effectively promoted periosteal regeneration, including osteogenic and angiogenic processes. The osteoarthritis cartilage histopathology assessment and histologic/histochemical grading system data indicate that the TEPSs containing hMSCs/HUVECs/HDFs exhibit superior potential for cartilage regeneration.

Double membrane platelet-rich fibrin (PRF) - Synovium succeeds in regenerating cartilage defect at the knee: An experimental study on rabbit

Background

This study aims to prove the healing results (regeneration) in cartilage defects using a combination treatment of microfractures and transplantation synovium-platelet rich fibrin (S-PRF).

Methods

A cartilage defect was made in the trochlear groove of the knee of adult New Zealand white rabbits, and was classified into three treatment groups. The group 1 was cartilage defect without treatment, 2 with microfracture treatment, and 3 with microfracture covered with a synovium-platelet rich fibrin (S-PRF) membrane. Twelve weeks after the intervention, the animals were macroscopically and histologically examined, and evaluated by the International Cartilage Repair Society (ICRS). Additionally, the expression of aggrecan and type 2 collagen was examined by real-time-PCR.

Results

The ICSR scores for macroscopic were significantly higher in the microfracture and S-PRF transplant group than in the other groups. Also, the ICSR scores for histology were significantly higher in this group. The expression of aggrecan and type 2 collagen was higher in the group that received complete treatment.

Conclusions

Microfractures and transplantation of synovium-platelet rich fibrin (S-PRF) can regenerate knee cartilage defects which have been shown to increase the expression of mRNA aggrecan and mRNA type 2 collagen resulting in excellent repair.

Mid- to Long-Term Clinical Outcomes of Cartilage Restoration of Knee Joint with Allogenic Next-Generation Matrix-Induced Autologous Chondrocyte Implantation (MACI)

OBJECTIVE

Cartilage defect is a common pathology still lacking a unified treating option. The purpose of this retrospective study is to evaluate the safety, efficacy, and clinical and radiological outcome of cartilage restoration of knee joint with allogenic next-generation Matrix-Induced Autologous Chondrocyte Implantation (MACI) for the first time, as well as the correlation between postoperative clinical and radiological outcomes and preoperative patient history and demographics.

METHODS

From July 2014 to August 2020, 15 patients who went through cartilage restoration with allogenic next-generation MACI were included in this study. Patient demographics and PROM including the International Knee Documentation Committee (IKDC) subjective knee score, Lysholm score, Tegner Activity Scale (TAS), and Knee Injury and Osteoarthritis Outcome Score (KOOS) were obtained preoperatively, at 3, 6, 12 months postoperatively and the last follow-up using an online questionnaire platform. MOCART 2.0 score was calculated at the last follow-up. Analysis of variance (ANOVA) was used to compare PROM pre- and post-operation, with two-tailed p < 0.05 defined as statistical significant. Pearson correlation coefficient was used to evaluate correlation between the PROM and MOCART 2.0 score at the last follow-up with patients demorgraphics.

RESULTS

All patients were followed for an average of 66.47 ± 24.15 months (range, 21-93). All patients were satisfied with the outcome of the surgery and no complication was reported at the end of the study. No significant improvement was observed until 1 year after the implantation, except for IKDC score at 6 months. All PROM showed significant improvement 1 year post-op except for Lysholm score and TAS, which also increased significantly at the time of the last follow-up. Pearson correlation coefficient showed that the size of the defect, before or after debridement, was significantly negatively correlated with final KOOS-Pain (before debridement: r = -0.57, p < 0.05; after debridement: r = -0.54, p < 0.05) and KOOS-Symptoms score (before debridement: r = -0.66, p < 0.05; after debridement: r = -0.67, p < 0.05). The MOCART 2.0 score was found significantly and negatively correlated with BMI (r = -0.60, p < 0.05), and significantly and positively correlated with Lysholm score (r = 0.70, p < 0.05).

CONCLUSION

The next generation MACI with autologous chondrocyte and allogenic chondrocyte ECM scaffold could be used to treat focal articular cartilage defect in the knee joint safely and efficiently with lasting promising outcomes for more than 5 years. The size of the defects should be considered the most negatively correlated parameters influencing the postoperative clinical outcomes.

Bone marrow stimulation in arthroscopic rotator cuff repair is a cost-effective and straightforward technique to reduce retear rates: A systematic review and meta-analysis

Background

Bone marrow stimulation (BMS) has been considered a well-established method for treating knee and ankle osteochondral lesions. Some studies have also shown that BMS can promote healing of the repaired tendon and enhance biomechanical properties during rotator cuff repair. Our purpose was to compare the clinical outcomes of arthroscopic repair rotator cuff (ARCR) with and without BMS.

Methods

A systematic review with meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). PubMed, Embase, Web of Science, Google scholar, ScienceDirect, and the Cochrane Library were searched from inception to March 20, 2022. Data on retear rates, shoulder functional outcomes, visual analog score and range of motion were pooled and analyzed. Dichotomous variables were presented as odds ratios (OR), and continuous variables were presented as mean differences (MD). Meta-analyses were conducted with Review Manager 5.3.

Results

Eight studies involving 674 patients were included, with mean follow-up period ranging from 12 to 36.8 months. Compared to ARCR alone, the intraoperative combination of the BMS resulted in lower retear rates (P < 0.0001), but showed similar results in Constant score (P = 0.10), University of California at Los Angeles (UCLA) score (P = 0.57), American Shoulder and Elbow Surgeons (ASES) score (P = 0.23), Disabilities of the Arm, Shoulder and Hand (DASH) score (P = 0.31), VAS (visual analog score) score (P = 0.34), and range of motion (ROM) (forward flexion, P = 0.42; external rotation, P = 0.21). After sensitivity analyses and subgroup analyses, no significant changes in statistical results were observed.

Conclusion

Compared to ARCR alone, the combination of intraoperative BMS can significantly reduce the retear rates, but showed similar short-term results in functional outcomes, ROM and pain. Better clinical outcomes are anticipated in the BMS group by improving structural integrity during long-term follow-up. Currently, BMS may be a viable option in ARCR based on its straightforward and cost-effective advantages.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, identifier: CRD42022323379.

Bone Marrow-Derived Fibrin Clots Stimulate Healing of a Meniscal Defect in a Rabbit Model

PURPOSE

To determine the in vivo effectiveness of bone marrow aspirate-derived (BMA) fibrin clots for avascular meniscal defect healing in a rabbit model.

METHODS

In 42 Japanese white rabbits, a 2.0-mm cylindrical defect was introduced into the avascular zone of the anterior part of the medial meniscus in the bilateral knees. The rabbits were grouped according to implantation of a BMA fibrin clot (BMA group) or a peripheral blood (PB)-derived clot (PB group) into the defect and nonimplantation (control group). Macroscopic and histological assessments were performed using a scoring system at 4 and 12 weeks after surgery. At 12 weeks after surgery, compressive stress was analyzed biomechanically.

RESULTS

The meniscal score in the BMA group (12.1) was greater than that in the PB group (5.5; P = .031) and control group (4.4; P = .013) at 4 weeks. The meniscal score in the BMA group (13.1) was greater than that in the control group (6.4; BMA = 13.1; P = .0046) at 12 weeks. In the biomechanical analysis, the BMA group demonstrated significantly higher compressive strength than the PB group (6.6 MPa) (BMA = 15.4 MPa; P = .0201) and control group (3.6 MPa; BMA = 15.4 MPa; P = .007).

CONCLUSIONS

Implantation of BMA fibrin clots into the meniscal defect of the avascular zone in a rabbit model improved the meniscal score at 4 weeks and strengthened the reparative meniscal tissue at 12 weeks compared with the implantation of PB fibrin clots.

CLINICAL RELEVANCE

Healing in the avascular zone of the meniscus can be problematic. Approaches to improving this healing response have had variable results. This study provides additional information that may help improve the outcomes in patients with these injuries.

The sternum reconstruction: Present and future perspectives

Sternectomy is a procedure mainly used for removing tumor masses infiltrating the sternum or treating infections. Moreover, the removal of the sternum involves the additional challenge of performing a functional reconstruction. Fortunately, various approaches have been proposed for improving the operation and outcome of reconstruction, including allograft transplantation, using novel materials, and developing innovative surgical approaches, which promise to enhance the quality of life for the patient. This review will highlight the surgical approaches to sternum reconstruction and the new perspectives in the current literature.

Fixation of an Osteochondral Lesion of the Femoral Intercondylar Groove Using Autogenous Osteochondral Grafts and Bioabsorbable Pins in a Patient with Open Physes: A Case Report

Osteochondral lesion (OCL) of the patellofemoral (PF) joint is not an uncommon cause of knee pain, and surgery is needed when conservative treatment fails. However, there is a lack of evidence regarding the optimal surgical treatment for OCL of the PF joint. Fixation of OCLs using autogenous osteochondral grafts has been reported to be effective for OCL of the knee. However, in this surgical technique, the biomechanical strength of osteochondral grafts may not be sufficient in patients with open physes due to the specific quality of the cartilage and subchondral bone given their age. There is a lack of studies reporting fixation of the OCL located in the PF joint using autogenous osteochondral grafts. We herein report a case of OCL of the femoral intercondylar groove where autogenous osteochondral grafts augmented with bioabsorbable pins were used to fix the lesion in a 14-year-old patient with open physes. Preoperative MRI revealed a completely detached OCL of the intercondylar groove (36 mm × 20 mm). Although a total of four osteochondral grafts were harvested from the non-weightbearing area of the lateral femoral condyle, cartilage detached from one of the grafts. The quality of the osteochondral grafts was considered to be insufficient for stabilization of the OCL; thus, two bioabsorbable pins were additionally inserted following fixation of the lesion using three osteochondral grafts. After two years of follow-up, postoperative functional scores were favorable without knee pain. The present case suggests that fixation of the OCL using autogenous osteochondral grafts may not be appropriate for young patients with open physes.

Glenoid microfracture in active-duty military patients: minimum 5-year follow-up demonstrates 75% survival

Background

To present midterm patient-reported outcomes and survivorship data of active-duty military patients undergoing microfracture for full-thickness cartilage defects of the glenoid.

Methods

All consecutive patients from January 2013 through December 2016 who underwent glenoid microfracture for full-thickness cartilage injuries with complete outcome scores were identified. Twenty patients met the final inclusion criteria for the study, and all were active-duty military at the time of surgery. A separate subgroup analysis was performed to determine if dominant-shoulder involvement portends worse outcomes.

Results

The mean follow-up was 81.45 ± 19.43 months (range, 60-108). Of the 20 patients, 5 required a secondary surgical procedure within 5 years of their index procedure, with an average time to failure of 45.6 ± 13.15 months. For the 15 patients who did not fail, there was a statistically significant increase in the mean American Shoulder and Elbow Surgeons score (57.20 vs. 88.27, P < .0001) and Single Assessment Numeric Evaluation (45.00 vs. 86.33, P < .0001). Mean pain decreased significantly as measured by the pain visual analog scale (5.40 vs. 1.37, P < .0001). Range of motion in forward elevation, external rotation, and internal rotation did not change significantly postoperatively (P = .4528, .4810, and .1919, respectively). Concomitant procedures did not predict changes in pain, American Shoulder and Elbow Surgeons, or Single Assessment Numeric Evaluation scores. A majority of patients (13/20, 65%) were able to remain on unrestricted military active-duty service, but 7 (35%) underwent medical discharge, including the 5 patients who had experienced treatment failure, plus 2 additional patients.

Conclusion

Glenoid microfracture can result in pain relief and symptomatic improvement for a select group of active-duty military patients, with 75% survivorship at 5 years. Approximately one in three (35%) patients, however, were unable to remain on active-duty military service.

Blood flow restriction added to usual care exercise in patients with early weight bearing restrictions after cartilage or meniscus repair in the knee joint: a feasibility study

PURPOSE

Blood flow restriction - low load strength training (BFR-LLST) is theoretically superior to traditional heavy strength training when rehabilitating patients who cannot heavily load tissues following surgery. The main purpose of this study was to examine the feasibility of BFR-LLST added to usual care exercise early after cartilage or meniscus repair in the knee joint.

METHODS

We included 42 patients with cartilage (n = 21) or meniscus repair (n = 21) of the knee joint. They attended 9 weeks of BFR-LLST added to a usual care exercise program at an outpatient rehabilitation center. Outcome measures were assessed at different time points from four (baseline) to 26 weeks postoperatively and included adherence, harms, knee joint and thigh pain, perceived exertion, thigh circumference (muscle size proxy), isometric knee-extension strength, self-reported disability and quality of life.

RESULTS

On average, patients with cartilage or meniscus repair completed > 84% of the total BFR-LLST supervised sessions. Thirty-eight patients reported 146 adverse events of which none were considered serious. No decrease in thigh circumference or exacerbation of knee joint or quadriceps muscle pain of the operated leg was found in either group during the intervention period.

CONCLUSIONS

BFR-LLST added to usual care exercise initiated early after cartilage or meniscus repair seems feasible and may prevent disuse thigh muscle atrophy during a period of weight bearing restrictions. Harms were reported, but no serious adverse events were found. Our findings are promising but need replication using a RCT-design.

TRIAL REGISTRATION

NCT03371901 , preprint (open access):  https://www.medrxiv.org/content/10.1101/2022.03.31.22272398v1.

Hip Arthroscopic Microfracture Augmented With Platelet-Rich Plasma-Infused Micronized Cartilage Allograft Significantly Improves Functional Outcomes

PURPOSE

To evaluate functional outcomes and survivorship in patients at 1 year after undergoing arthroscopic microfracture augmented with hyaline allograft for symptomatic chondral defects of the hip.

METHODS

Consecutive patients with and without prior hip procedures presenting with Outerbridge grade IV chondral lesion of the acetabulum or femoral head were prospectively followed. Patients underwent hip microfracture augmented with hyaline allograft suspended in autologous platelet-rich plasma between October 2016 and April 2018. Extent of cartilage degeneration was quantified using the chondromalacia severity index (CMI). Patient functional scores, including Tegner, Hip Outcome Score-Activities of Daily Living (HOS-ADL), Sport-Specific Subscale (HOS-SSS), modified Harris Hip Score (mHHS), and Nonarthritic Hip Score (NAHS) were collected preoperatively and at minimum 1-year postoperatively. Minimal clinically important difference (MCID) was analyzed. Statistical significance was established at P < .05. Pearson's coefficient analysis was performed to identify preoperative variables correlated with clinical outcomes.

RESULTS

Fifty-seven patients (86.4%) had minimum 1-year follow-up and were included in the final analysis, with a mean age and body mass index (BMI) of 38.3 ± 9.1 years and 27.7 ± 4.9 kg/m², respectively. Comparison of baseline and postoperative score averages demonstrated significant improvements in Tegner scores (3.7 ± 2.9 vs 5.1 ± 2.6; P = .003), HOS-ADL (63.3 ± 16.4 vs 89.1 ± 14.5; P < .001), HOS-SSS (40.8 ± 20.4 vs 79.5 ± 21.6; P < .001), mHHS (61.5 ± 16.2 vs 87.0 ± 17.7; P < .001), and NAHS (56.6 ± 14.9 vs 78.7 ± 18.3; P < .001). The percentage of patients who achieved MCID for HOS-ADL, HOS-SSS, mHHS, and NAHS were 89.8%, 83.0%, 75.6%, and 81.6%, respectively. Overall, 91.8% of patients met the threshold for achieving MCID in at least one outcome score. Of the 57 patients, 5 (8.8%) failed clinically, with 1 (1.8%) undergoing revision surgery and 4 (6.9%) undergoing conversion to total hip arthroplasty. There was a direct correlation between preoperative alpha angle and postoperative HOS-ADL. Femoral chondral lesion size and CMI inversely correlated with postoperative HOS-ADL.

CONCLUSIONS

Treatment of hip chondral defects with microfracture and hyaline allograft augmentation demonstrated excellent survivorship and significantly improved patient report outcomes at 1 year.

LEVEL OF EVIDENCE

IV, retrospective case series.

After Chondroplasty, Patient Election to Proceed With Cartilage Transplantation Is Closely and Additively Associated With Preoperative AMADEUS (Area Measurement And DEpth Underlying Structure) Grade, Condylar Involvement, Knee Injury and Osteoarthritis Outcome Score Pain Score, and Veterans Rand 12-Item Health Survey Physical Score

Purpose

To identify risk factors for patient election to proceed with cartilage transplant after staging chondroplasty.

Methods

This study retrospective reviewed patients prospectively enrolled at the time of staging chondroplasty, with early election defined as patient decision to proceed to cartilage transplantation within 6 months of chondroplasty. Cox proportional hazards analysis was used to determine univariate predictors of conversion, and a predictive calculator, the Cartilage Early Return for Transplant score, was formulated using stepwise regression employing the Akaike information criterion. Receiver operator curves and the area under the curve were used to evaluate the predictive ability of the final model on the studied patient population.

Results

Sixty-five knees (63 patients) were evaluated, with an overall transplant election rate of 27.7% within 6 months after chondroplasty. Based on multivariate results, the final Akaike information criterion-driven Cartilage Early Return for Transplant score employed preoperative Knee Injury and Osteoarthritis Outcome Score Pain Score, Veterans Rand 12-Item Health Survey Physical Score, condylar involvement, and AMADEUS (Area Measurement And DEpth Underlying Structure) score to generate a 0- to 7-point risk-stratification system with a 3% early election to proceed to transplant risk in the 0- to 2-point score group, 33% risk in the 3- to 4-point group, and 79% risk in the 5+-point group (P < .01) and an overall AUC of 0.906 (P < .01).

Conclusions

Risk of early patient election to pursue cartilage transplantation after chondroplasty is closely and additively associated with preoperative AMADEUS grade, condylar involvement, Knee Injury and Osteoarthritis Outcome Score Pain Score, and Veterans Rand 12-Item Health Survey Physical Score.

Clinical Relevance

Understanding risk factors for conversion to cartilage transplantation may improve preoperative planning and counseling prior to staging chondroplasty.

Cartilaginous Metabolomics Reveals the Biochemical-Niche Fate Control of Bone Marrow-Derived Stem Cells

Joint disorders have become a global health issue with the growth of the aging population. Screening small active molecules targeting chondrogenic differentiation of bone marrow-derived stem cells (BMSCs) is of urgency. In this study, microfracture was employed to create a regenerative niche in rabbits (n = 9). Cartilage samples were collected four weeks post-surgery. Microfracture-caused morphological (n = 3) and metabolic (n = 6) changes were detected. Non-targeted metabolomic analysis revealed that there were 96 differentially expressed metabolites (DEMs) enriched in 70 pathways involved in anti-inflammation, lipid metabolism, signaling transduction, etc. Among the metabolites, docosapentaenoic acid 22n-3 (DPA) and ursodeoxycholic acid (UDCA) functionally facilitated cartilage defect healing, i.e., increasing the vitality and adaptation of the BMSCs, chondrogenic differentiation, and chondrocyte functionality. Our findings firstly reveal the differences in metabolomic activities between the normal and regenerated cartilages and provide a list of endogenous biomolecules potentially involved in the biochemical-niche fate control for chondrogenic differentiation of BMSCs. Ultimately, the biomolecules may serve as anti-aging supplements for chondrocyte renewal or as drug candidates for cartilage regenerative medicine.

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.