Autologous bone grafting in combination with autologous chondrocyte implantation yields favourable outcomes in the treatment of osteochondral defects of the knee: A systematic literature review.

PURPOSE: This study addresses the gap in the current literature by evaluating the combined treatment of autologous bone grafting and autologous chondrocyte implantation (ABCI) for osteochondral defects of the knee. It aims to evaluate clinical outcomes against methodological quality and to summarize histological results and surgical techniques. METHODS: A thorough search was conducted across Pubmed, Cochrane and Embase databases. Studies reporting clinical outcomes of ABCI for osteochondral defects of the knee were included. Patient-reported outcome measures (PROMs), failure rates, methodological quality and potential conflicts of interest were evaluated. Histological results and surgical techniques were summarized. RESULTS: Eighteen studies with 344 analyzed patients met the eligibility criteria for inclusion. All studies showed a significant improvement (p < 0.05) across different PROMs (subjective International Knee Documentation Committee score, Cincinnati Knee Rating System, Visual Analogue Scale, Lysholm Score, Tegner Activity Scale, Knee injury and Osteoarthritis Outcome Score and Knee Society Score) compared to the preoperative status. Failure rates ranged from 0% to 17.6%, with a mean follow-up of 73.2 months (range: 9.0-143.6 months). Methodological quality was low to medium, including only one comparative study. Six studies reviewed reported a potential conflict of interest. The histological assessment showed effective bonding between autologous chondrocytes and bone graft. A large degree of variability was observed in the operative technique used. CONCLUSION: The current literature suggests that ABCI yields good clinical outcomes at mid- to long-term follow-up with favourable histological results for osteochondral defects of the knee. However, future research should focus on high-quality comparative studies to better guide treatment choices. Introducing ABCI as the standard abbreviation may enhance clarity in future research. LEVEL OF EVIDENCE: Level IV.

An evaluation of a novel method for the MRI-based assessment of Caton-Deschamps index in the Knee.

INTRODUCTION: The radiographical assessment of patella height has historically been performed using X-Ray. The aim of this study was to evaluate a new method for the assessment of patella height using MRI and to assess the correlation with the X-Ray based assessment. MATERIALS AND METHODS: 159 patients who had both lateral radiographs and MRI images were included. Parameters measured included traditional radiographical CDI, MRI-based CDI, and TT-TG distance. On the basis of the TT-TG, the patients were divided into 2 groups. Two different methods were used to assess CDI using MRI: using a single slice image, and an alternative technique using two different cross-sectional images. The correlation of the two measurement methods was assessed using Pearson's correlation coefficient. The intraclass correlation coefficient (ICC) was determined from the measurements of the two investigators. RESULTS: The average TT-TG distance was 11.6 mm (± 4.6). In patients with a TT-TG < 15 mm, both measurement methods showed comparable correlation with measurements on X-Ray. In patients with a TT-TG of > 15 the the new cross-sectional imaging method showed higher correlation with traditional X-Ray assessment compared to CDI assessment using the traditional single slice method (r = 0.594, p < 0.001 vs. r = 0.302, p = 0.055). CONCLUSIONS: The assessment of CDI on MRI using a cross-sectional imaging method has a better correlation with traditional X-Ray assessment of CDI than single-slice assessment. This is particularly true in patients with elevated TT-TG and as such should be preferentially used in the assessment of Patellar height in this cohort.

Metabolic reprogramming of synovial fibroblasts in osteoarthritis by inhibition of pathologically overexpressed pyruvate dehydrogenase kinases.

Osteoarthritis (OA) is the most common degenerative joint disease and a major cause of age-related disability worldwide, mainly due to pain, the disease's main symptom. Although OA was initially classified as a non-inflammatory joint disease, recent attention has been drawn to the importance of synovitis and fibroblast-like synoviocytes (FLS) in the pathogenesis of OA. FLS can be divided into two major populations: thymus cell antigen 1 (THY1)- FLS are currently classified as quiescent cells and assumed to destroy bone and cartilage, whereas THY1+ FLS are invasively proliferative cells that drive synovitis. Both THY1- and THY1+ FLS share many characteristics with fibroblast-like progenitors - mesenchymal stromal cells (MSC). However, it remains unclear whether synovitis-induced metabolic changes exist in FLS from OA patients and whether metabolic differences may provide a mechanistic basis for the identification of approaches to precisely convert the pathologically proliferative synovitis-driven FLS phenotype into a healthy one. To identify novel pathological mechanisms of the perpetuation and manifestation of OA, we analyzed metabolic, proteomic, and functional characteristics of THY1+ FLS from patients with OA. Proteome data and pathway analysis revealed that an elevated expression of pyruvate dehydrogenase kinase (PDK) 3 was characteristic of proliferative THY1+ FLS from patients with OA. These FLS also had the highest podoplanin (PDPN) expression and localized to the sublining but also the lining layer in OA synovium in contrast to the synovium of ligament trauma patients. Inhibition of PDKs reprogrammed metabolism from glycolysis towards oxidative phosphorylation and reduced FLS proliferation and inflammatory cytokine secretion. This study provides new mechanistic insights into the importance of FLS metabolism in the pathogenesis of OA. Given the selective overexpression of PDK3 in OA synovium and its restricted distribution in synovial tissue from ligament trauma patients and MSC, PDKs may represent attractive selective metabolic targets for OA treatment. Moreover, targeting PDKs does not affect cells in a homeostatic, oxidative state. Our data provide an evidence-based rationale for the idea that inhibition of PDKs could restore the healthy THY1+ FLS phenotype. This approach may mitigate the progression of OA and thereby fundamentally change the clinical management of OA from the treatment of symptoms to addressing causes.

Bacterial contamination of irrigation fluid and suture material during ACL reconstruction and meniscus surgery : Low infection rate despite increasing contamination over surgery time.

PURPOSE: During knee arthroscopy, irrigation fluid from the surgical site accumulates in the sterile reservoir. Whether these fluid collections and also suture material used during the arthroscopic surgical processes show bacterial contamination over time during surgery remains unclear. The purpose of this study was to determine this contamination rate and to analyze its possible influence on postoperative infection. MATERIALS AND METHODS: In this study, 155 patients were included. Fifty-eight underwent reconstruction of the anterior cruciate ligament (ACL), 63 meniscal surgery and 34 patients combined ACL reconstruction and meniscus repair. We collected pooled samples of irrigation fluid from the reservoir on the sterile drape every 15 min during the surgery. In addition, we evaluated suture material of ACL graft and meniscus repair for bacterial contamination. Samples were sent for microbiological analysis, incubation time was 14 days. All patients were seen in the outpatient department 6, 12 weeks and 12 months postoperatively and examined for clinical signs of infection. RESULTS: A strong statistical correlation (R2 = 0.81, p = 0.015) was found between an advanced duration of surgery and the number of positive microbiological findings in the accumulated fluid. Suture and fixation material showed a contamination rate of 28.4% (29 cases). Despite the high contamination rate, only one infection was found in the follow-up examinations, caused by Staphylococcus lugdunensis. CONCLUSION: Since bacterial contamination of accumulated fluid increases over time the contact with the fluid reservoirs should be avoided. LEVEL OF EVIDENCE: IV.

The subjective knee value is a valid single-item survey to assess knee function in common knee disorders.

INTRODUCTION: The patient's perspective plays a key role in judging the effect of knee disorders on physical function. We have introduced the Subjective Knee Value (SKV) to simplify the evaluation of individual's knee function by providing one simple question. The purpose of this prospective study was to validate the SKV with accepted multiple-item knee surveys across patients with orthopaedic knee disorders. MATERIALS AND METHODS: Between January through March 2020, consecutive patients (n = 160; mean age 51 ± 18 years, range from 18 to 85 years, 54% women) attending the outpatient clinic for knee complaints caused by osteoarthritis (n = 69), meniscal lesion (n = 45), tear of the anterior cruciate ligament (n = 23) and focal chondral defect (n = 23) were invited to complete a knee-specific survey including the SKV along with the Knee Injury Osteoarthritis Outcome Score (KOOS) and the International Knee Documentation Committee subjective knee form (IKDC-S). The Pearson correlation coefficient was used to evaluate external validity between the SKV and each patient-reported outcome measure (PROM) separately. Furthermore, patient's compliance was assessed by comparing responding rates. RESULTS: Overall, the SKV highly correlated with both the KOOS (R = 0.758, p < 0.05) and the IKDC-S (R = 0.802, p < 0.05). This was also demonstrated across all investigated diagnosis- and demographic-specific (gender, age) subgroups (range 0.509-0.936). No relevant floor/ceiling effects were noticed. The responding rate for the SKV (96%) was significantly higher when compared with those for the KOOS (81%) and the IKDC-S (83%) (p < 0.05). CONCLUSION: At baseline, the SKV exhibits acceptable validity across all investigated knee-specific PROMs in a broad patient population with a wide array of knee disorders. The simplified survey format without compromising the precision to evaluate individual's knee function justifies implementation in daily clinical practice. LEVEL OF EVIDENCE: II, cohort study (diagnosis).

[Influence of the COVID-19 pandemic on the physiotherapeutic and medical follow-up care after reconstructions of the anterior cruciate ligament]. / Einfluss der COVID-19-Pandemie auf die physiotherapeutische und ärztliche Nachsorge nach Rekonstruktionen des vorderen Kreuzbandes.

BACKGROUND: The aim of this study was to examine the influence of the COVID-19(coronavirus disease 2019) pandemic on the medical and physiotherapeutic follow-up care after reconstructions of the anterior cruciate ligament. METHODS: 116 patients (72 men and 44 women) who had received a reconstruction of the anterior cruciate ligament between September 2019 and December 2020 were included in this study. These patients were divided into two groups depending on the date of surgery: one group that had received surgery in 2019 before the COVID-19 pandemic and one group that had undergone surgery in 2020 and was directly affected by the COVID-19 pandemic. All patients were interviewed using a standardized questionnaire regarding the influence of the coronavirus pandemic on the medical and physiotherapeutic follow-up care, as well as the moment of return to work. In addition, the range of motion of the respective knee 3 months postoperatively was analysed based on physical examination. RESULTS: At 3 months postoperatively, patients who had undergone surgery in 2020 showed a clear trend towards a higher frequency of extension deficits of ≥ 5° (18.8% vs. 4.3%, p = 0.097) or an inability to bend the knee ≥ 120° (23.3% vs. 10%, p = 0.197) compared to those who had received surgery in 2019. Patients who had undergone surgery in 2020 reported significantly longer delays for appointments, a higher number of futile attempts to get an appointment and a higher number of cancelled appointments, regarding both medical and physiotherapeutic follow-up care. 34.9% of the patients who received surgery in 2020 indicated that they were able to reduce the duration of their sick leave due to the increased possibilities of working in a home-office situation during the pandemic. Alternative treatment options due to the pandemic were offered by 13.3% of the physiotherapists and 12.2% of the physicians. CONCLUSION: Although the physiotherapeutic and medical follow-up care was not directly affected by a "lockdown", the pandemic led to significant restrictions, which are also reflected in a clear trend towards worse clinical outcomes. Consequently, a further expansion of alternative treatment options, which were only offered by 12-13% of practices and that are presumably of comparable relevance for various other diseases, is needed.

Validation of Synovial Aspiration in Girdlestone Hips for Detection of Infection Persistence in Patients Undergoing 2-Stage Revision Total Hip Arthroplasty.

BACKGROUND: The aim of this study was to assess the diagnostic performance of synovial aspiration in Girdlestone hips, without a Polymethylmethacrylate (PMMA) spacer, for the detection of infection persistence before total hip arthroplasty (THA) reimplantation. METHODS: Seventy-four patients undergoing stage revision THA surgery were included in this retrospective cohort study. Both synovial cultures and serum C-reactive protein values were acquired before explantation of the THA and of the Girdlestone hip before reimplantation. RESULTS: The diagnostic performance of the synovial aspiration of the Girdlestone hip achieved a sensitivity of only 13% and a specificity of 98%. The determination of the serum C-reactive protein value for Girdlestone hips achieved a sensitivity of 95% and a specificity of only 20%. CONCLUSIONS: Our data show that the Girdlestone aspiration can neither reliably confirm nor exclude a persistence of infection.

Assessment of Quality and Readability of Information Provided by ChatGPT in Relation to Anterior Cruciate Ligament Injury.

The aim of our study was to evaluate the potential role of Artificial Intelligence tools like ChatGPT in patient education. To do this, we assessed both the quality and readability of information provided by ChatGPT 3.5 and 4 in relation to Anterior Cruciate Ligament (ACL) injury and treatment. ChatGPT 3.5 and 4 were used to answer common patient queries relating to ACL injuries and treatment. The quality of the information was assessed using the DISCERN criteria. Readability was assessed with the use of seven readability formulae: the Flesch-Kincaid Reading Grade Level, the Flesch Reading Ease Score, the Raygor Estimate, the SMOG, the Fry, the FORCAST, and the Gunning Fog. The mean reading grade level (RGL) was compared with the recommended 8th-grade reading level, the mean RGL among adults in America. The perceived quality and mean RGL of answers given by both ChatGPT 3.5 and 4 was also compared. Both ChatGPT 3.5 and 4 yielded DISCERN scores suggesting "good" quality of information, with ChatGPT 4 slightly outperforming 3.5. However, readability levels for both versions significantly exceeded the average 8th-grade reading level for American patients. ChatGPT 3.5 had a mean RGL of 18.08, while the mean RGL of ChatGPT 4 was 17.9, exceeding the average American reading grade level by 10.08 grade levels and 9.09 grade levels, respectively. While ChatGPT can provide both reliable and good quality information on ACL injuries and treatment options, the readability of the content may limit its utility. Additionally, the consistent lack of source citation represents a significant area of concern for patients and clinicians alike. If AI is to play a role in patient education, it must reliably produce information which is accurate, easily comprehensible, and clearly sourced.

Altered knee kinematics after posterior cruciate ligament single-bundle reconstruction-a comprehensive prospective biomechanical in vivo analysis.

Purpose: Passive tibiofemoral anterior-posterior (AP) laxity has been extensively investigated after posterior cruciate ligament (PCL) single-bundle reconstruction. However, the PCL also plays an important role in providing rotational stability in the knee. Little is known in relation to the effects of PCL single-bundle reconstruction on passive tibiofemoral rotational laxity. Gait biomechanics after PCL reconstruction are even less understood. The aim of this study was a comprehensive prospective biomechanical in vivo analysis of the effect of PCL single-bundle reconstruction on passive tibiofemoral rotational laxity, passive anterior-posterior laxity, and gait pattern. Methods: Eight patients undergoing PCL single-bundle reconstruction (seven male, one female, mean age 35.6 ± 6.6 years, BMI 28.0 ± 3.6 kg/m2) were analyzed preoperatively and 6 months postoperatively. Three of the eight patients received additional posterolateral corner (PLC) reconstruction. Conventional stress radiography was used to evaluate passive translational tibiofemoral laxity. A previously established rotometer device with a C-arm fluoroscope was used to assess passive tibiofemoral rotational laxity. Functional gait analysis was used to examine knee kinematics during level walking. Results: The mean side-to-side difference (SSD) in passive posterior translation was significantly reduced postoperatively (12.1 ± 4.4 mm vs. 4.3 ± 1.8 mm; p < 0.01). A significant reduction in passive tibiofemoral rotational laxity at 90° knee flexion was observed postoperatively (27.8° ± 7.0° vs. 19.9° ± 7.5°; p = 0.02). The range of AP tibiofemoral motion during level walking was significantly reduced in the reconstructed knees when compared to the contralateral knees at 6-month follow-up (16.6 ± 2.4 mm vs. 13.5 ± 1.6 mm; p < 0.01). Conclusion: PCL single-bundle reconstruction with optional PLC reconstruction reduces increased passive tibiofemoral translational and rotational laxity in PCL insufficient knees. However, increased passive tibiofemoral translational laxity could not be fully restored and patients showed altered knee kinematics with a significantly reduced range of tibiofemoral AP translation during level walking at 6-month follow-up. The findings of this study indicate a remaining lack of restoration of biomechanics after PCL single-bundle reconstruction in the active and passive state, which could be a possible cause for joint degeneration after PCL single-bundle reconstruction.

PCL insufficient patients with increased translational and rotational passive knee joint laxity have no increased range of anterior-posterior and rotational tibiofemoral motion during level walking.

Passive translational tibiofemoral laxity has been extensively examined in posterior cruciate ligament (PCL) insufficient patients and belongs to the standard clinical assessment. However, objective measurements of passive rotational knee laxity, as well as range of tibiofemoral motion during active movements, are both not well understood. None of these are currently quantified in clinical evaluations of patients with PCL insufficiency. The objective of this study was to quantify passive translational and rotational knee laxity as well as range of anterior-posterior and rotational tibiofemoral motion during level walking in a PCL insufficient patient cohort as a basis for any later clinical evaluation and therapy. The laxity of 9 patient knees with isolated PCL insufficiency or additionally posterolateral corner (PLC) insufficiency (8 males, 1 female, age 36.78 ± 7.46 years) were analysed and compared to the contralateral (CL) knees. A rotometer device with a C-arm fluoroscope was used to assess the passive tibiofemoral rotational laxity while stress radiography was used to evaluate passive translational tibiofemoral laxity. Functional gait analysis was used to examine the range of anterior-posterior and rotational tibiofemoral motion during level walking. Passive translational laxity was significantly increased in PCL insufficient knees in comparison to the CL sides (15.5 ± 5.9 mm vs. 3.7 ± 1.9 mm, p < 0.01). Also, passive rotational laxity was significantly higher compared to the CL knees (26.1 ± 8.2° vs. 20.6 ± 5.6° at 90° knee flexion, p < 0.01; 19.0 ± 6.9° vs. 15.5 ± 5.9° at 60° knee flexion, p = 0.04). No significant differences were observed for the rotational (16.3 ± 3.7° vs. 15.2 ± 3.6°, p = 0.43) and translational (17.0 ± 5.4 mm vs. 16.1 ± 2.8 mm, p = 0.55) range of anterior-posterior and rotational tibiofemoral motion during level walking conditions for PCL insufficient knees compared to CL knees respectively. The present study illustrates that patients with PCL insufficiency show a substantial increased passive tibiofemoral laxity, not only in tibiofemoral translation but also in tibiofemoral rotation. Our data indicate that this increased passive multiplanar knee joint laxity can be widely compensated during level walking. Further studies should investigate progressive changes in knee joint laxity and kinematics post PCL injury and reconstruction to judge the individual need for therapy and effects of physiotherapy such as quadriceps force training on gait patterns in PCL insufficient patients.

Analysis of cartilage injury patterns and risk factors for knee joint damage in patients with primary lateral patella dislocations.

BACKGROUND: Lateral patellar dislocation (LPD) frequently causes damage to the knee. Injury patterns and risk factors contributing to such injuries have not yet been examined in detail. METHODS: We retrospectively analyzed 50 consecutive patients with primary LPD. Two reviewers evaluated the MRI images regarding risk factors for LPD (Dejours classification; Caton-Deschamps Index, CDI; distance from the tibial tuberosity to trochlear groove, TT-TG; trochlear depth, TD) as well as joint damages according to the Whole-Organ Magnetic Resonance Imaging Score (WORMS). RESULTS: 33 male and 17 female patients with a mean age of 23.2 (±9.6) years were included in this study. 52% were classified Dejours ≥ B, 34% had a CDI ≥ 1.3, 22% a TT-TG ≥ 20mm and 52% a TD < 3mm. 49 out of 50 patients (98%) showed abnormalities according to WORMS. The most frequently observed abnormalities were synovitis/effusion (49/50, 98%), bone marrow oedema (44/50, 88%) and cartilage damage (42/50, 84%). Most frequently affected subregions were medial (41/50, 82%) and lateral (31/50, 62%) patella as well as the anterior (43/50, 86%), central (42/50, 84%) and posterior (11/50, 22%) portion of the lateral femoral condyle. There was no significant correlation between any of the examined risk factors and joint damages according to WORMS. Male patients had higher scores regarding total cartilage damage (5.11 vs. 2.56, p = 0.029), total score for the lateral femorotibial joint (3.15 vs. 1.65, p = 0.026) and overall total WORMS score (12.15 vs. 8.29, p = 0.038). CONCLUSION: Risk factors for LPD do not influence the risk of damages to the knee joint after primary LPD. Although LPD is generally known to affect more female than male patients, male patients suffered more severe injuries after primary LPD, particularly of the lateral femorotibial joint. Overall, our results underline the importance of MRI imaging after primary LPD.

Increased rate of bacterial colonization on PE-components in total joint arthroplasty: An evaluation through sonication.

BACKGROUND: It is currently unclear if an isolated exchange of the mobile components, in cases of periprosthetic joint infection (PJI), leads to a complete eradication of all bacteria or if residual bacteria remain attached to the retained components? OBJECTIVE: The purpose of this study was to investigate if bacteria only adhere to certain components or materials, or if they are ubiquitously distributed throughout the joint. METHODS: Twenty hundred and eighty four patients undergoing revision total hip or total knee arthroplasty surgery were included in this retrospective cohort study. Synovial fluid cultures, periprosthetic tissue cultures, histological samples and sonicate fluid cultures (SFC) from the individual endoprosthetic components were acquired. The isolated bacterial species were recorded according to their endoprosthetic component of origin. RESULTS: In 72% of all cases with multiple SFC, the cultures were concordant with all samples being either homogenously negative or showing positive bacterial growth. The polyethylene (PE) components showed a significantly higher rate of bacterial isolation than the non-mobile components. All components and materials showed bacterial colonization, however between all other components or materials were not statistically significant. CONCLUSIONS: PE-components show a higher rate of bacterial isolation than other components. If an isolated bearing exchange is performed this should be supplemented by adequate antimicrobial therapy.

Superior angiogenic potential of GDF-5 and GDF-5(V453/V456) compared with BMP-2 in a rabbit long-bone defect model.

BACKGROUND: The clinical application of bone morphogenetic proteins such as BMP-2 and GDF-5 (growth and differentiation factor-5) may improve the outcome of bone defect repair. In addition to the osteoinductivity of BMPs, their angiogenic potential is important as an adequate blood supply is a prerequisite for bone-healing. We used a rabbit long-bone defect model to investigate whether angiogenicity and osteogenicity were correlated features of a BMP molecule by comparing the induction of blood vessel and bone formation by BMP-2, GDF-5, and a previously created swap mutant GDF-5V453/V456 (BB-1) with elevated BMP receptor-IA binding. METHODS: Microcomputed tomography and immunohistochemistry were used to assess early bone formation and neovascularization in 15-mm (critical-sized) rabbit radius defects treated with a growth factor-loaded collagen carrier. RESULTS: Blood vessel volume and surface area on days 7 and 14 after surgery were significantly greater in defects treated with GDF-5 and with BB-1 compared with controls (p < 0.05); BMP-2 enhanced vascularization on day 14 (p < 0.05). Cumulative data including both time points reflected increased vessel volume, intersection surface area, and number of vessels after treatment with GDF-5 and BB-1 compared with BMP-2 (p < 0.05), corresponding to the histology results. Each of the growth factors resulted in enhanced bone formation compared with controls on day 14 (p < 0.01), with BB-1 resulting in significantly more bone compared with GDF-5 as indicated by bone volume and surface area (p = 0.006). CONCLUSIONS: Both GDF-5 and BB-1 had high angiogenicity, and BB-1 outperformed GDF-5 with respect to osteogenicity. Strong induction of bone formation by BMP-2 and BB-1 was thus associated with BMP receptor-IA-dependent signaling, whereas the vascularization outcome was not. CLINICAL RELEVANCE: Although both BMP-2 and the GDF-5 variant BB-1 are good inducers of bone formation, BB-1 is especially promising for long-bone healing if high angiogenicity is desired along with high osteogenicity to promote recreation of optimal bone architecture.