Achilles tendinosis: changes in biochemical composition and collagen turnover rate

Understanding biochemical and structural changes of the extracellular matrix in Achilles tendinosis might be important for developing mechanism-based therapies. In Achilles tendinosis, changes occur in biochemical composition and collagen turnover rate. Descriptive laboratory study. From 10 patients undergoing surgery for Achilles tendinopathy, 1 tendinosis biopsy specimen and 1 biopsy specimen of macroscopically healthy tendon tissue adjacent to the lesion were collected. Furthermore, biopsy samples were collected from 3 donors with asymptomatic Achilles tendons. Water content, collagen content, percentage of denatured collagen, amount of lysine hydroxylation, number of enzymatic and nonenzymatic crosslinks, matrix metalloproteinase activity, and matrix metalloproteinase and collagen gene-expression levels were analyzed. In tendinotic lesions, the water content was highest, and collagen content was subnormal with higher amounts of denatured/damaged collagen. Low pentosidine levels in tendinotic tissue indicated the presence of relatively young collagenous matrix. More hydroxylated lysine residues were present in tendinotic samples, but enzymatic crosslinks revealed no differences between tendinotic, adjacent, and healthy samples. In tendinotic specimens, matrix metalloproteinase activity was higher, matrix metalloproteinase gene-expression profile was altered, and collagen type I and III gene expression were upregulated. In Achilles tendinosis, the collagen turnover rate is increased, and the natural biochemical composition of the collagenous matrix is compromised. Although tendon tissue directly adjacent to an Achilles tendinosis lesion looks macroscopically healthy, histological and biochemical degenerative changes in adjacent tissue are evident, which may have implications for surgical intervention

Intra-operative assessment of the vascularisation of a cross section of the meniscus using near-infrared fluorescence imaging

PURPOSE: The purpose of this study was to assess whether the vascularisation of the meniscus could be visualised intra-operatively using near-infrared fluorescence (NIRF) imaging with indocyanine green (ICG) in patients undergoing total knee arthroplasty (TKA). METHODS: The anterior horn (i.e., Cooper classification: zones C and D) of the meniscus that was least affected (i.e., least degenerative) was removed during TKA surgery in ten patients to obtain a cross section of the inside of the meniscus. Thereafter, 10 mg of ICG was injected intravenously, and vascularisation of the cross section of the meniscus was assessed using the Quest spectrum NIRF camera system. We calculated the percentage of patients in whom vascularisation was observed intra-operatively using NIRF imaging compared to immunohistochemistry. RESULTS: Meniscal vascularisation using NIRF imaging was observed in six out of eight (75%) patients in whom vascularisation was demonstrated with immunohistochemistry. The median extent of vascularisation was 13% (interquartile range (IQR) 3-28%) using NIRF imaging and 15% (IQR 11-23%) using immunohistochemistry. CONCLUSION: This study shows the potential of NIRF imaging to visualise vascularisation of the meniscus, as vascularisation was observed in six out of eight patients with histologically proven meniscal vascularisation. LEVEL OF EVIDENCE: IV

Responsiveness and Minimal Important Change of the IKDC of Middle-Aged and Older Patients With a Meniscal Tear

Background: Responsiveness and the minimal important change (MIC) are important measurement properties to evaluate treatment effects and to interpret clinical trial results. The International Knee Documentation Committee (IKDC) Subjective Knee Form is a reliable and valid instrument for measuring patient-reported knee-specific symptoms, functioning, and sports activities in a population with meniscal tears. However, evidence on responsiveness is of limited methodological quality, and the MIC has not yet been established for patients with symptomatic meniscal tears. Purpose: To evaluate the responsiveness and determine the MIC of the IKDC for patients with meniscal tears. Study Design: Cohort study (design); Level of evidence 2. Methods: This study was part of the ESCAPE trial: a noninferiority multicenter randomized controlled trial comparing arthroscopic partial meniscectomy with physical therapy. Patients aged 45 to 70 years who were treated for a meniscal tear by arthroscopic partial meniscectomy or physical therapy completed the IKDC and 3 other questionnaires (RAND 36-Item Health Survey, EuroQol-5D-5L, and visual analog scales for pain) at baseline and 6-month follow-up. Responsiveness was evaluated by testing predefined hypotheses about the relation of the change in IKDC with regard to the change in the other self-reported outcomes. An external anchor question was used to distinguish patients reporting improvement versus no change in daily functioning. The MIC was determined by the optimal cutoff point in the receiver operating characteristic curve, which quantifies the IKDC score that best discriminated between patients with and without improvement in daily function. Results: Data from all 298 patients who completed baseline and 6-month follow-up questionnaires were analyzed. Responsiveness of the IKDC was confirmed in 7 of 10 predefined hypotheses about the change in IKDC score with regard to other patient-reported outcome measures. One hypothesis differed in the expected direction, while 2 hypotheses failed to meet the expected magnitude by 0.02 and 0.01 points. An MIC of 10.9 points was calculated for the IKDC of middle-aged and older patients with meniscal tears. Conclusion: This study showed that the IKDC is responsive to change among patients aged 45 to 70 years with meniscal tears, with an MIC of 10.9 points. This strengthens the value of the IKDC in quantifying treatment effects in this population

Thromboprophylaxis after Knee Arthroscopy and Lower-Leg Casting

Background The use of thromboprophylaxis to prevent clinically apparent venous thromboembolism after knee arthroscopy or casting of the lower leg is disputed. We compared the incidence of symptomatic venous thromboembolism after these procedures between patients who received anticoagulant therapy and those who received no anticoagulant therapy. Methods We conducted two parallel, pragmatic, multicenter, randomized, controlled, open-label trials with blinded outcome evaluation: the POT-KAST trial, which included patients undergoing knee arthroscopy, and the POT-CAST trial, which included patients treated with casting of the lower leg. Patients were assigned to receive either a prophylactic dose of low-molecular-weight heparin (for the 8 days after arthroscopy in the POT-KAST trial or during the full period of immobilization due to casting in the POT-CAST trial) or no anticoagulant therapy. The primary outcomes were the cumulative incidences of symptomatic venous thromboembolism and major bleeding within 3 months after the procedure. Results In the POT-KAST trial, 1543 patients underwent randomization, of whom 1451 were included in the intention-to-treat population. Venous thromboembolism occurred in 5 of the 731 patients (0.7%) in the treatment group and in 3 of the 720 patients (0.4%) in the control group (relative risk, 1.6; 95% confidence interval [CI], 0.4 to 6.8; absolute difference in risk, 0.3 percentage points; 95% CI, -0.6 to 1.2). Major bleeding occurred in 1 patient (0.1%) in the treatment group and in 1 (0.1%) in the control group (absolute difference in risk, 0 percentage points; 95% CI, -0.6 to 0.7). In the POT-CAST trial, 1519 patients underwent randomization, of whom 1435 were included in the intention-to-treat population. Venous thromboembolism occurred in 10 of the 719 patients (1.4%) in the treatment group and in 13 of the 716 patients (1.8%) in the control group (relative risk, 0.8; 95% CI, 0.3 to 1.7; absolute difference in risk, -0.4 percentage points; 95% CI, -1.8 to 1.0). No major bleeding events occurred. In both trials, the most common adverse event was infection. Conclusions The results of our trials showed that prophylaxis with low-molecular-weight heparin for the 8 days after knee arthroscopy or during the full period of immobilization due to casting was not effective for the prevention of symptomatic venous thromboembolism. (Funded by the Netherlands Organization for Health Research and Development; POT-KAST and POT-CAST ClinicalTrials.gov numbers, NCT01542723 and NCT01542762 , respectively.)