Donor age has no relevant role in biomechanical properties of allografts used in anterior cruciate ligament (ACL) reconstruction: A systematic review.

PURPOSE: Surgeons generally consider the donor age as a factor that negatively influences the quality of allograft used in anterior cruciate ligament (ACL) reconstruction, however, the available evidence does not clearly support this statement. The purpose of the study was to investigate if donor age influences the biomechanical properties of allografts used in ACL reconstruction. METHODS: A comprehensive literature search was conducted for all relevant articles using MEDLINE (PubMed), Scopus, and Cochrane Collaboration Library, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis. Studies including the analysis of the correlation between biomechanical properties of the allografts and donor age were selected. The role of donor age was labelled as 'none' if absent, 'higher' or 'lower' if the properties were higher or lower in older specimens with respect to younger. The correlation was defined as 'weak' or 'strong' according to each study definition. RESULTS: No conflicting role of donor age was reported for modulus of elasticity, load to failure, strain, stiffness and displacement. The only parameters where the significant results were consistent were the tensile strength and the stress (low or moderate correlations). When considering the tested samples with a donor's age <65 years, a significant role of age was reported in only four out of 13 groups of graft tested (patellar tendon, fascia lata, anterior tibialis tendon and posterior tibialis tendon). CONCLUSION: The current literature did not allow to state that the donor age negatively influences the biomechanical properties of allografts, making it impossible to identify a clear age cut-off value to exclude them from ACL reconstruction procedures. LEVEL OF EVIDENCE: Level IV, systematic review.

All-Polyethylene Versus Metal-Backed Tibial Components in Total Knee Arthroplasty: A Meta-Analysis of Randomized Controlled Trials.

BACKGROUND: In the literature, there is no evidence suggesting the superiority in clinical performance between all-polyethylene (AP) and metal-backed (MB) tibial implants in total knee arthroplasty. The aim of this study was to systematically review the literature to collect only high-quality studies investigating the differences in terms of clinical and radiostereometric analysis (RSA) outcomes of AP compared to MB implants. METHODS: Only randomized controlled trials (RCTs) reporting either clinical or RSA outcomes have been included. Data sources were Embase, Medline, and the Cochrane Central Register of Controlled Trials. RESULTS: We included eleven RCTs evaluating the outcomes of 1,377 patients. Of the RCTs, 9 of them showed a low risk and 2 showed moderate risk of bias. There was no statistically significant difference in terms of clinical outcomes and survival rate between the AP and MB group; however, a statistically significant lower mean lift-off in the AP group (0.19 mm) compared to the MB group (0.3 mm) was observed on RSA. CONCLUSIONS: The performance of AP total knee arthroplasty in terms of clinical outcomes and 5-year survival was not statistically different when compared to the MB group. However, the RSA showed a statistically significant lower mean lift-off in the AP group.

Placenta-Derived Products Demonstrate Good Safety Profile and Overall Satisfactory Outcomes for Treating Knee Osteoarthritis: A Systematic Review of Clinical Evidence.

PURPOSE: To summarize the available evidence regarding the clinical application of placenta-derived products to treat knee osteoarthritis (OA), underlining the differences existing among products, their preparation methods, and the clinical results reported so far. METHODS: A research on PubMed, Cochrane, and Google Scholar databases was performed. The following inclusion criteria for relevant articles were used: (1) randomized controlled trials (RCTs), prospective and retrospective studies, on humans; (2) written in English; (3) published in indexed journals in the last 10 years (2011-2022); and (4) dealing with the use of placenta-derived products for the treatment of knee OA. Exclusion criteria were articles written in other languages; animals or in vitro trials; reviews; and trials analyzing other applications of placenta-derived products not related to knee OA. RESULTS: In total, 16 studies were included in the present systematic review. Five studies investigated placenta-derived products as an augmentation during surgical procedures, whereas 11 studies were focused on the injective approach only. Of these, only 4 were RCTs and were all from the injective approach group. Potential risk of bias was carried out using Cochrane Risk of Bias 2 tool for RCTs and a modified Coleman approach for nonrandomized studies, revealing for both an overall insufficient quality. Clinical outcomes reveal excellent safety profile and notable efficacy, despite the different types of products used and different administration methods adopted. CONCLUSIONS: Placental products showed a good safety profile and overall satisfactory outcomes for the treatment of knee OA. LEVEL OF EVIDENCE: Level IV, systematic review of Level II, III and IV studies.

Double-bundle non-anatomic ACL revision reconstruction with allograft resulted in a low revision rate at 10 years.

PURPOSE: This study aimed at reporting the long-term second revision rate and subjective clinical outcomes from a cohort of patients who underwent a double-bundle (DB) ACLR first revision with allograft at a single institution. METHODS: The Institutional database was searched according to the following inclusion criteria: (1) patients that underwent DB-ACL first revision with Achilles tendon allograft, (2) surgery performed between January 2000 and December 2012, (3) age at revision ≥ 18 y/o. Patients' general information, history, surgical data, and personal contacts were extracted from charts. An online survey platform was implemented to collect responses via email. The survey questions included: date of surgeries, surgical data, date of graft failure and subsequent second ACL revision surgery, any other surgery of the index knee, contralateral ACLR, KOOS score, and Tegner scores. RESULTS: Eighty-one patients were included in the survival analysis, mean age at revision 32 ± 9.2 y/o, 71 males, mean BMI 24.7 ± 2.7, mean time from ACL to revision 6.8 ± 5.4 years, mean follow-up time 10.7 ± 1.4 years. There were 12 (15%) second ACL revisions during the follow-up period, three females and nine males, at a mean of 4.5 ± 3 years after the index surgery. The overall survival rates were 85% from a second ACL revision and 68% from all reoperations of the index knee. Considering only the successful procedures (61 patients), at final follow-up, the mean values for the KOOS subscales were 84 ± 15.5 for Pain, 88.1 ± 13.6 for Symptoms, 93 ± 11.6 for ADL, 75 ± 24.5 for Sport, and 71 ± 19.6 for Qol. Twenty-nine (48%) patients performed sports activity at the same level as before ACLR failure. CONCLUSIONS: Double-bundle ACL revision with fresh-frozen Achilles allograft yields satisfactory results at long-term follow-up, with an 85% survival rate from a second ACL revision at mean 10 years' follow-up and good patient-reported clinical scores. LEVEL OF EVIDENCE: Level IV.

Long sports career and satisfactory clinical outcomes after Meniscal Allograft Transplantation (MAT) in young professional athletes involved in strenuous sports.

PURPOSE: To assess the return to sport rate of young professional athletes, to analyze their careers in terms of matches played and league participation over a minimum period of 6 years after Meniscal Allograft Transplantation (MAT), as well as to assess the long-term clinical subjective outcomes and satisfaction. METHODS: Thirteen professional athletes (ten soccer and one basketball players, one fencer and one wrestler) with a mean age at surgery of 23.4 ± 4.0 underwent MAT (six medial, seven lateral). The time required to return to sport, post-operative performance level and the number of reoperations were evaluated. At an average follow-up of 9.0 ± 2.8 years, Lysholm, KOOS and Cincinnati scores were administered and collected. RESULTS: Thirteen patients (100%) returned to sports practice after an average period of 11.8 ± 3.8 months. Nine athletes (69%) returned to sports at the same pre-injury level. Overall, 93%, 85%, 62% and 55% were active until the 3rd, the 5th, the 7th and the 9th season after MAT, respectively. Seven patients (54%) underwent a reoperation after MAT, where only two of them (15%) were related to graft problems (one meniscectomy and one graft suture). Of the ten athletes that completed subjective evaluation, the mean Lysholm score was 72 ± 15 (0% "Excellent", 10% "Good", 60% "Fair", 30% "Poor"). Of the athletes with lower scores, one suffered from patellar tendon rupture, one from post-operative infection and one from a previous femoral fracture. The mean Cincinnati knee score was 77 ± 18, while the average KOOS values were 60 ± 34 for sports. CONCLUSION: Meniscal Allograft Transplantation (MAT) in young professional athletes involved in strenuous activities allowed all patients to return to pre-injury sport and in nearly 70% of cases at their pre-injury level. After five seasons following MAT, 85% of patients were still active or playing more than 20-30 matches per season. On the other hand, nearly 50% underwent at least one reoperation and only 70% of patients were rated as "Good", or "Fair" using the Lysholm score. LEVEL OF EVIDENCE: IV.

High return to sport rate and few re-ruptures at long term in professional footballers after anterior cruciate ligament reconstruction with hamstrings.

PURPOSE: Anterior cruciate ligament (ACL) ruptures are considered high burden injuries in sports with high pivotal activity, especially for professional footballers. A lack of evidence exists about long-term follow up of professional elite athletes who underwent ACL reconstruction. The purpose of the study is to analyze the return to play and the career of professional footballers who underwent ACL reconstruction with hamstrings, to evaluate re-rupture and reoperation at either indexed and contralateral knee, and to assess the long-term clinical subjective outcomes and satisfaction. METHODS: Twenty-eight professional footballers that underwent 33 ACL reconstructions were retrospectively included in the study. All surgical interventions were performed using hamstring tendons graft and an over the top technique. Inclusion criteria were: inability to compete due to joint instability caused by total or subtotal ACL lesion, patients contracted to a professional football team at time of surgery. Exclusion criteria were: multi-ligament reconstruction or concomitant meniscal allograft transplantation. Patients were contacted by phone and a brief questionnaire about surgery was administered. Subsequently, a Lysholm knee scoring scale was obtained. After that, an online research was performed on publicly available websites in order to retrieve information of the patients included after surgery. RESULTS: In all cases, ACL Reconstruction was performed with hamstring tendons using a non-anatomic Double-Bundle technique in 16 cases (49%), an Over-The-Top Single-Bundle technique in 9 cases (27%), and an Over-The-Top Single-Bundle plus Lateral Plasty technique in 8 cases (24%); moreover, a meniscal lesion was present in 20 cases (61%). Three (9%) of the 33 ACL reconstruction failed (2/16 Double-Bundle, 1/9 Single- Bundle, 0/8 Single-Bundle + Lateral Plasty; p = n.s.), with two of them within 12 months from surgery. Other procedures, mainly arthroscopic meniscectomies, were performed in 10 cases (30%). The first official match was played after an average of 8.0 ± 3.6 (4.6-18.2) months in 31 cases (94%). Patients were evaluated after 12.6 ± 3.3 years (6.7-17.5) from the indexed ACL reconstruction. The average Lysholm score was 94.2 ± 8.3. CONCLUSIONS: In our small case-series, professional soccer players were able to return to play at a competitive level with a hamstrings over the top technique. Patients with long careers had a high percentage of reoperation on the contralateral knee. LEVEL OF EVIDENCE: IV.

Psychological factors and trajectories of post-surgical pain: A longitudinal prospective study.

A significant proportion of patients do not experience relief from pain during the early postsurgical period after joint arthroplasty and are at risk for developing chronic pain. The objectives of this study were to identify biopsychosocial factors associated with acute postsurgical pain trajectories and with pain intensity and interference after 1, 3, and 12 months. Two hundred ten patients listed for joint arthroplasty filled a presurgical battery of questionnaires assessing presurgical pain intensity, catastrophizing, emotional distress, state anxiety and depression, self-efficacy, central sensitization, and executive functions. From the day after surgery, they were asked to fill a 7-day diary, including questions about postsurgical pain and postsurgical state catastrophizing. Finally, they provided data about pain intensity and interference after 1, 3, and 12 months. Predictors of acute pain trajectories were investigated using multilevel growth curve analysis. Results showed that central sensitization was a predictor of the intercept of pain trajectories and daily postsurgical catastrophizing was a significant covariate of pain intensity in the acute phase. Analyses of follow-up data showed that central sensitization was a predictor of pain intensity and pain interference at 3 and 12 months, that emotional distress was related with pain intensity and interference at 1 month, and with pain interference at 3 months, and that cognitive flexibility was associated with pain interference at 1 month. Assessment of these factors could enable to identify patients at risk for worse outcomes and to plan targeted treatments to be implemented during the patient's inward stay.

High survivorship rate and good clinical outcomes at mid-term follow-up for lateral UKA: a systematic literature review.

PURPOSE: The purpose of this paper is to systematically review the available literature to understand the effectiveness, the survivorship, the clinical outcomes and the complications of lateral UKA. METHODS: A review of the current literature available about lateral UKA was performed in March 2020, according to the PRISMA guidelines. Selection was based on the following inclusion criteria: (1) clinical reports of any level of evidence, (2) written in English language, (3) published from 1996 to 2020, (4) dealing with clinical data on lateral UKA. A total of 47 articles, published between 1996 and 2020, were included in the review. Quality of every article was assessed using the Modified Coleman Methodology Score. RESULTS: A total of 47 studies were included. Mean mCMS was 45.27 (range 30-62). Mean age at surgery was 64.5 years (range 34.1-88.0 years). In 1741 patients (65.5%) a metal back implant was used and in 421 patients (15.8%) an all poly design was used. Several scores were used to evaluate clinical results (OKS, AKSS, IKS, KOOS, WOMAC, VAS). Range of motion improved with an overall mean value of 120.3° (range: 105.9°-143.3°). The mean follow-up was 60.7 months (range, 7-204 months), mean survivorship (absence of a revision) with a minimum 60 months of follow-up was 88.6% (range 74.5-100) and mean satisfaction of patients was 78.5% (range 41.0-97.9). CONCLUSIONS: Lateral UKA seems to be an effective solution to manage lateral osteoarthritis (OA), based on preliminary results, with survivorship and satisfaction rate comparable to medial UKA and total knee arthroplasty (TKA). Nonetheless, this review highlights that the quality of studies available in current literature is low. LEVEL OF EVIDENCE: Systematic review of level IV studies.

Satisfactory clinical results and low failure rate of medial collagen meniscus implant (CMI) at a minimum 20 years of follow-up.

PURPOSE: The aim of the study was to evaluate the long-term clinical results, reoperations, surgical failure and complications at a minimum of 20 year of follow-up of the first 8 medial CMI scaffolds implanted by a single surgeon during a pilot European Prospective study. METHODS: Seven (88%) out of 8 patients were contacted. The Cincinnati Score, VAS, and Lysholm score were collected. Moreover, magnetic resonance imaging (MRI) was performed on 4 patients at the last follow-up. Complications, reoperations and failures were also investigated. RESULTS: The average follow-up was 21.5 ± 0.5 years. One patient underwent TKA after 13 years from CMI implantation; a second patient underwent valgus high tibial osteotomy 8 years after the index surgery and another patient underwent anterior cruciate ligament hardware removal at 21 years of follow-up. At the final follow-up, 3 patients were rated as "Excellent", 1 as "Good" and 2 as "Fair" according to the Lysholm score. The Cincinnati score and the VAS were substantially stable over time. The MRI showed a mild osteoarthritis progression in 3 out of 4 patients according to the Yulish score, and the CMI signal was similar to the mid-term follow-up revealing 3 cases of myxoid degeneration and 1 case of normal signal with reduced scaffold size. CONCLUSION: The medial CMI is a safe procedure: satisfactory clinical results and a low failure rate could be expected even at a long-term follow-up. For this purpose, the correct indication as well as correcting axial malalignment and addressing knee instability at the time of the index surgery is mandatory. On the other hand, a mild osteoarthritis progression could be expected even after meniscus replacement. LEVEL OF EVIDENCE: IV.

Subchondral and intra-articular injections of bone marrow concentrate are a safe and effective treatment for knee osteoarthritis: a prospective, multi-center pilot study.

PURPOSE: Subchondral bone is becoming a treatment target for knee OA patients, with promising early findings on the use of bone marrow aspirate concentrate (BMAC). The aim of this prospective, multi-centric pilot study was to evaluate safety as well as clinical and MRI outcomes of a combined approach of intra-articular and subchondral BMAC injections. METHODS: Thirty patients (19 men, 11 women, 56.4 ± 8.1 years) with symptomatic knee OA were treated with a combination of an intra-articular and two subchondral BMAC injections (femoral condyle and tibial plateau). Patients were evaluated at baseline and at 1-3-6-12 months of follow-up with the IKDC subjective, VAS, KOOS, and EQ-VAS scores. The MRI evaluation was performed with the WORMS score. RESULTS: No major complications were reported and only two patients were considered treatment failures, requiring a new injective or surgical treatment. The IKDC subjective score improved significantly from 40.5 ± 12.5 to 59.9 ± 16.1 at 3 months, 59.1 ± 12.2 at 6 months, and 62.6 ± 19.4 at 12 months (p < 0.0005). A similar improvement was reported for VAS pain and all KOOS subscales at all follow-ups, while EQ-VAS did not show any significant improvement. The MRI analysis showed a significant bone marrow edema reduction (p = 0.003), while the remaining WORMS parameters did not show any significant changes. CONCLUSION: The pilot evaluation of this combined BMAC injective treatment showed safety and positive outcome up to 12 months of follow-up in patients with symptomatic knee OA associated with subchondral bone alterations. These findings suggest that targeting both subchondral bone and joint environment can provide promising results, and that BMAC can be a valid option for this combined approach to treat knee OA.

Evaluation of cartilage biomechanics and knee joint microenvironment after different cell-based treatments in a sheep model of early osteoarthritis.

PURPOSE: Aiming to prevent cartilage damage during early osteoarthritis (OA), the therapeutic challenge is to restore and maintain the physiological and functional properties of such a tissue with minimally invasive therapeutic strategies. METHODS: Accordingly, an in vivo model of early OA in sheep was here treated through three different cell therapies (culture expanded ADSCs, SVF, and culture expanded AECs) thus to preserve the joint surface from the progression of the pathology. Three months after the treatment injections, their performance was assessed through mechanical automated mapping (Young's modulus and cartilage thickness), gross evaluation of articular surfaces, and biochemical analysis of the synovial fluid. RESULTS: No severe degeneration was observed after three months from OA induction. Cartilage mechanical properties were crucial to identify early degeneration. All the treatments improved the macroscopic cartilage surface aspect and reduced pro-inflammatory cytokines in the synovial fluid. Among the three treatments, SVF highlighted the best performance while ADSCs the worst. CONCLUSION: Despite that the evaluated experimental time is an early follow-up and, thus, longer trial is mandatory to properly assess treatments effectiveness, the proposed multidisciplinary approach allowed to obtain preliminary, but also crucial, results concerning the reduction in OA signs on cartilage properties, in osteophyte development and in all the inflammatory markers.

Non-Coding RNAs in the Transcriptional Network That Differentiates Skeletal Muscles of Sedentary from Long-Term Endurance- and Resistance-Trained Elderly.

In a previous study, the whole transcriptome of the vastus lateralis muscle from sedentary elderly and from age-matched athletes with an exceptional record of high-intensity, life-long exercise training was compared-the two groups representing the two extremes on a physical activity scale. Exercise training enabled the skeletal muscle to counteract age-related sarcopenia by inducing a wide range of adaptations, sustained by the expression of protein-coding genes involved in energy handling, proteostasis, cytoskeletal organization, inflammation control, and cellular senescence. Building on the previous study, we examined here the network of non-coding RNAs participating in the orchestration of gene expression and identified differentially expressed micro- and long-non-coding RNAs and some of their possible targets and roles. Unsupervised hierarchical clustering analyses of all non-coding RNAs were able to discriminate between sedentary and trained individuals, regardless of the exercise typology. Validated targets of differentially expressed miRNA were grouped by KEGG analysis, which pointed to functional areas involved in cell cycle, cytoskeletal control, longevity, and many signaling pathways, including AMP-activated protein kinase (AMPK) and mammalian target of rapamycin (mTOR), which had been shown to be pivotal in the modulation of the effects of high-intensity, life-long exercise training. The analysis of differentially expressed long-non-coding RNAs identified transcriptional networks, involving lncRNAs, miRNAs and mRNAs, affecting processes in line with the beneficial role of exercise training.

Skeletal Muscle Gene Expression in Long-Term Endurance and Resistance Trained Elderly.

Physical exercise is deemed the most efficient way of counteracting the age-related decline of skeletal muscle. Here we report a transcriptional study by next-generation sequencing of vastus lateralis biopsies from elderly with a life-long high-level training practice (n = 9) and from age-matched sedentary subjects (n = 5). Unsupervised mixture distribution analysis was able to correctly categorize trained and untrained subjects, whereas it failed to discriminate between individuals who underwent a prevalent endurance (n = 5) or a prevalent resistance (n = 4) training, thus showing that the training mode was not relevant for sarcopenia prevention. KEGG analysis of transcripts showed that physical exercise affected a high number of metabolic and signaling pathways, in particular those related to energy handling and mitochondrial biogenesis, where AMPK and AKT-mTOR signaling pathways are both active and balance each other, concurring to the establishment of an insulin-sensitive phenotype and to the maintenance of a functional muscle mass. Other pathways affected by exercise training increased the efficiency of the proteostatic mechanisms, consolidated the cytoskeletal organization, lowered the inflammation level, and contrasted cellular senescence. This study on extraordinary individuals who trained at high level for at least thirty years suggests that aging processes and exercise training travel the same paths in the opposite direction.

Meniscal Allograft Transplantation Is an Effective Treatment in Patients Older Than 50 Years but Yields Inferior Results Compared With Younger Patients: A Case-Control Study.

PURPOSE: To evaluate the influence of age on midterm clinical outcomes and failures of meniscal allograft transplantation (MAT), aiming at investigating the efficacy of MAT in patients older than 50 years. METHODS: In this case-control study, data on patients older than 50 years (older MAT [O-MAT] group) with at least 5 years of follow-up and a matched-pair group of patients younger than 30 years of age (younger MAT [Y-MAT] group) were extracted from a database of MAT procedures, performed with arthroscopic implantation of fresh-frozen meniscal allograft without bone plugs. RESULTS: A matched-pair comparative analysis of midterm results and survival between 26 O-MAT patients and 26 Y-MAT patients was performed at a mean follow-up of 7.3 ± 2.2 years. All the clinical scores significantly improved from the baseline values in both the O-MAT and Y-MAT groups although with significantly lower scores in the O-MAT group. Two-thirds of O-MAT patients were able to return to a recreational level of sports activity. Only 2 patients in the O-MAT group underwent knee replacement, but the overall failure rate, also considering a clinical criterion, was 31% in the O-MAT group and 15% in the Y-MAT group (P = .3244). The mean survival time free from replacement or graft removal was 11.6 years in the O-MAT group and 12.3 years in the Y-MAT group (P = .691). CONCLUSIONS: MAT is able to provide symptom relief and functional improvement at midterm follow-up in patients older than 50 years although with inferior results and a higher failure rate compared with those younger than 30 years. MAT can be considered a viable option to treat patients older than 50 years. LEVEL OF EVIDENCE: Level III, case-control study.

Meniscal allograft transplantation combined with anterior cruciate ligament reconstruction provides good mid-term clinical outcome.

PURPOSE: Aim of this study is to document if combined meniscal allograft transplantation (MAT) and ACL reconstruction can improve knee function, reduce pain and allow patients with meniscal defect and ACL lesion to resume sport activities. METHODS: Fifty MAT, arthroscopically performed without bone plugs and combined with one-stage primary or revision ACL reconstruction, with or without high tibial osteotomy (HTO), were included. Patients (aged 38.2 ± 10.6 years, 87% males) were evaluated at a mean follow-up of 5 years with Lysholm, Tegner and VAS scores. Patient satisfaction was also recorded, together with complications and failures. RESULTS: VAS and Lysholm scores improved significantly (from 63.7 to 24.5 and from 60.6 to 82.7, respectively, p < 0.001), while the Tegner score did not reach pre-injury values (p < 0.001), but it improved significantly compared to pre-surgery values (from 2.8 to 4.6, p < 0.001). Medial MAT reported significantly better results compared to lateral MAT. Patients undergoing concomitant HTO reported a significantly higher decrease of VAS. Younger patients with higher pre-operative pain and lower activity level presented higher satisfaction. Eight patients needed a reoperation. Three patients were considered surgical failures while four were considered clinical failures, for a total of 15% failures. CONCLUSIONS: Meniscal allograft transplantation combined with ACL reconstruction represents a safe and suitable treatment, which should be considered as a suitable option in the clinical practice. All evaluated patient profiles, ACL injury in a patient with post-meniscectomy syndrome, failed ACL reconstruction in patients with a meniscus defect, and ACL reconstruction in patients with malalignment due to meniscal defect, benefited from the combined MAT procedure at medium-term follow-up. LEVEL OF EVIDENCE: IV.

A Composite Chitosan-Reinforced Scaffold Fails to Provide Osteochondral Regeneration.

Several biomaterials have recently been developed to address the challenge of osteochondral regeneration. Among these, chitosan holds promises both for cartilage and bone healing. The aim of this in vivo study was to evaluate the regeneration potential of a novel hybrid magnesium-doped hydroxyapatite (MgHA), collagen, chitosan-based scaffold, which was tested in a sheep model to ascertain its osteochondral regenerative potential, and in a rabbit model to further evaluate its ability to regenerate bone tissue. Macroscopic, microtomography, histology, histomorphometry, and immunohistochemical analysis were performed. In the sheep model, all analyses did not show significant differences compared to untreated defects (p > 0.05), with no evidence of cartilage and subchondral bone regeneration. In the rabbit model, this bone scaffold provided less ability to enhance tissue healing compared with a commercial bone scaffold. Moreover, persistence of scaffold material and absence of integration with connective tissue around the scaffolds were observed. These results raised some concerns about the osteochondral use of this chitosan composite scaffold, especially for the bone layer. Further studies are needed to explore the best formulation of chitosan-reinforced composites for osteochondral treatment.

Is Treatment With Dithiothreitol More Effective Than Sonication for the Diagnosis of Prosthetic Joint Infection?

BACKGROUND: Prosthetic joint infection (PJI) is among the most-severe complications of a total joint arthroplasty. Identification of the causal organism is of paramount importance for successful treatment, and sonication of implants may aid in this identification. Dithiothreitol (DTT) treatment has been proposed as an alternative to sonication to improve diagnosis, reduce costs, and improve reliability of the procedure, but its efficacy remains poorly characterized. QUESTIONS/PURPOSES: (1) Are DTT and sonication more sensitive and/or more specific than standard cultures of tissue samples for the diagnosis of PJI? (2) Which test (DTT or sonication) is more sensitive when the clinician does not suspect infection before surgery? (3) Which test (DTT or sonication) is more sensitive when the clinician suspects infection before surgery? METHODS: Two hundred thirty-two patients undergoing revision of a knee or hip arthroplasty were prospectively evaluated in this randomized study. Cultures were performed on five tissue samples from each patient and on fluid obtained by prosthesis treatment in patients randomly assigned to sonication (117 patients) or DTT (115 patients). The reference standard against which cultures (on tissue samples and on fluids from sonication or DTT) were compared was the Musculoskeletal Infection Society definition of PJI. RESULTS: Cultures on sonication and DTT fluids provided higher sensitivity (89% and 91%, respectively) than those on standard cultures of tissue samples (79%; p < 0.001). Among patients in whom infection was not suspected before surgery, the sensitivity of DTT was greater than that for sonication and cultures on tissue samples (100% versus 70% and 50%; p < 0.001). Among patients in whom infection was suspected before surgery, the sensitivity of DTT and sonication were not greater than that for standard cultures (89% and 94% versus 86%). CONCLUSIONS: In this randomized study, we found no difference in sensitivity between DTT and sonication for the detection of PJI, and both of those tests were more sensitive than standard tissue cultures. Thus, cultures of sonication or DTT fluid should be considered important additional tools to standard cultures for definition of PJI and should be considered together with other criteria, especially in settings where infection is not suspected before revision surgery.Level of Evidence Level I, diagnostic study.

Novel alginate biphasic scaffold for osteochondral regeneration: an in vivo evaluation in rabbit and sheep models.

Current therapeutic strategies for osteochondral restoration showed a limited regenerative potential. In fact, to promote the growth of articular cartilage and subchondral bone is a real challenge, due to the different functional and anatomical properties. To this purpose, alginate is a promising biomaterial for a scaffold-based approach, claiming optimal biocompatibility and good chondrogenic potential. A previously developed mineralized alginate scaffold was investigated in terms of the ability to support osteochondral regeneration both in a large and medium size animal model. The results were evaluated macroscopically and by microtomography, histology, histomorphometry, and immunohistochemical analysis. No evidence of adverse or inflammatory reactions was observed in both models, but limited subchondral bone formation was present, together with a slow scaffold resorption time.The implantation of this biphasic alginate scaffold provided partial osteochondral regeneration in the animal model. Further studies are needed to evaluate possible improvement in terms of osteochondral tissue regeneration for this biomaterial.