Decreased metalloproteinase production as a response to mechanical pressure in human cartilage: a mechanism for homeostatic regulation

Articular cartilage is optimised for bearing mechanical loads. Chondrocytes are the only cells present in mature cartilage and are responsible for the synthesis and integrity of the extracellular matrix. Appropriate joint loads stimulate chondrocytes to maintain healthy cartilage with a concrete protein composition according to loading demands. In contrast, inappropriate loads alter the composition of cartilage, leading to osteoarthritis (OA). Matrix metalloproteinases (MMPs) are involved in degradation of cartilage matrix components and have been implicated in OA, but their role in loading response is unclear. With this study, we aimed to elucidate the role of MMP-1 and MMP-3 in cartilage composition in response to mechanical load and to analyse the differences in aggrecan and type II collagen content in articular cartilage from maximum- and minimum-weight-bearing regions of human healthy and OA hips. In parallel, we analyse the apoptosis of chondrocytes in maximal and minimal load areas. Because human femoral heads are subjected to different loads at defined sites, both areas were obtained from the same hip and subsequently evaluated for differences in aggrecan, type II collagen, MMP-1, and MMP-3 content (enzyme-linked immunosorbent assay) and gene expression (real-time polymerase chain reaction) and for chondrocyte apoptosis (flow cytometry, bcl-2 Western blot, and mitochondrial membrane potential analysis). The results showed that the load reduced the MMP-1 and MMP-3 synthesis (p < 0.05) in healthy but not in OA cartilage. No significant differences between pressure areas were found for aggrecan and type II collagen gene expression levels. However, a trend toward significance, in the aggrecan/collagen II ratio, was found for healthy hips (p = 0.057) upon comparison of pressure areas (loaded areas > non-loaded areas). Moreover, compared with normal cartilage, OA cartilage showed a 10- to 20-fold lower ratio of aggrecan to type II collagen, suggesting that the balance between the major structural proteins is crucial to the integrity and function of the tissue. Alternatively, no differences in apoptosis levels between loading areas were found – evidence that mechanical load regulates cartilage matrix composition but does not affect chondrocyte viability. The results suggest that MMPs play a key role in regulating the balance of structural proteins of the articular cartilage matrix according to local mechanical demands

Return to sport soccer after anterior cruciate ligament reconstruction: ISAKOS consensus

Many factors can affect the return to pivoting sports, after an Anterior Cruciate Ligament Reconstruction. Prehabilitation, rehabilitation, surgical and psychological aspects&nbsp;play&nbsp;an essential role in the decision to return to sports. The purpose of this study is to reach an international consensus about the best conditions for returning to sports in soccer-one of the most demanding level I pivoting sports after anterior cruciate ligament (ACL) reconstruction

Bifurcated popliteus tendon: a descriptive arthroscopic study

The objective of this study was to confirm the presence and frequency of a bifurcation of the popliteus tendon. The popliteus tendon has received attention due to its important function as a knee stabiliser. Several anatomical variants have recently been reported, one of them being a bifurcated tendon. However, the actual frequency as well as the possible role of this particular variant is still unknown. We prospectively analysed a series of 1,569 arthroscopies between January 2005 to December 2007. Six asymptomatic bifurcated popliteus tendons were found. No alterations in the magnetic resonance imaging were seen and no clinical signs (related to the popliteus tendon) were observed in these patients before surgery. In all cases the morphological variant was found by chance. Our results suggest that the presence of a bifurcated popliteus tendon is a fact and that its frequency, not previously reported, should not be ignored

Topical and intravenous tranexamic acid reduce blood loss compared to routine hemostasis in total knee arthroplasty: a multicenter, randomized, controlled trial.

NTRODUCTION: Tranexamic acid (TXA) is becoming widely used in orthopedic surgery to reduce blood loss and transfusion requirements, but consensus is lacking regarding the optimal route and dose of administration. The aim of this study was to compare the efficacy and safety of topical and intravenous routes of TXA with routine hemostasis in patients undergoing primary total knee arthroplasty (TKA). MATERIALS AND METHODS: We performed a randomized, multicenter, parallel, open-label clinical trial in adult patients undergoing primary TKA. Patients were divided into three groups of 50 patients each: Group 1 received 1 g topical TXA, Group 2 received 2 g intravenous TXA, and Group 3 (control group) had routine hemostasis. The primary outcome was total blood loss. Secondary outcomes were hidden blood loss, blood collected in drains, transfusion rate, number of blood units transfused, adverse events, and mortality. RESULTS: One hundred and fifty patients were included. Total blood loss was 1021.57 (481.09) mL in Group 1, 817.54 (324.82) mL in Group 2 and 1415.72 (595.11) mL in Group 3 (control group). Differences in total blood loss between the TXA groups and the control group were clinically and statistically significant (p < 0.001). In an exploratory analysis differences between the two TXA groups were not statistically significant (p = 0.073) Seventeen patients were transfused. Transfusion requirements were significantly higher in Group 3 (p = 0.005). No significant differences were found between groups regarding adverse events. CONCLUSION:/nWe found that 1 g of topical TXA and 2 g of intravenous TXA were both safe strategies and more effective than routine hemostasis to reduce blood loss and transfusion requirements after primary TKA.This project was funded principally by a grant from the Spanish Ministry of Health and Social Policy to promote independent clinical research 2010 (EC10-73)

No differences in functional results and quality of life after single-radius or multiradius TKA.

PURPOSE: The main objective of this study was to compare the functional results and the impact on quality of life after a single-radius or a multiradius TKA implantation. The secondary objectives were to compare range of motion, satisfaction and the ability to perform daily life activities with both types of implant. It was hypothesized that the single-radius TKA would lead to better functional results and better quality of life than the multiradius TKA. METHODS: This is a prospective non-randomized study that included 250 cases of a single-radius TKA and 224 of a multiradius posterior-stabilized TKA implanted with the same surgical and rehabilitation protocol. RESULTS: In the 1- and 5-year follow-up, we found similar knee KSS scores (89.7 ± 12.1 in the multiradius group and 90.3 ± 11.7 in the single-radius group) and functional KSS scores (78.6 ± 21.4 in the multiradius group and 75.8 ± 20.9 in the single-radius group). The pain and the Physical SF-36 scores were also similar. Range of motion (112° ± 12° in the multiradius group and 112 ± 12° in the single-radius group), patients' satisfaction and the ability to perform daily life activities were also similar in both groups. CONCLUSION: The use of a single-radius or a multiradius posterior-stabilized knee prosthesis can improve the function of the knee and the patients' quality of life in a similar way at the short-term and midterm follow-up. Moreover, range of motion, patient satisfaction and the ability to perform daily life activities are similar with both types of prosthesis. As both types of prosthesis can improve the function and quality of life of the patients in a similar way, the sagittal radius of the femoral component should not be considered the main factor when choosing the model of TKA

Capsular fixation limits graft extrusion in lateral meniscal allograft transplantation

Purpose: The main purpose of this investigation was to compare the amount of graft extrusion of lateral meniscal allograft transplantation (MAT) performed with a suture-only technique with or without a capsulodesis. Secondarily, the assessment of functional results was also covered. We hypothesized that capsular fixation reduces the post-operative degree of allograft extrusion and it does not affect the functional outcomes during the short-term follow-up period studied. Methods: Prospective series of 29 lateral MAT. Fifteen were fixed with a suture-only technique (group A). The remaining 14 cases (group B) also included arthroscopic lateral capsular fixation (capsulodesis). Functional results were assessed with Lysholm, Tegner, and VAS for pain. Magnetic resonance imaging (MRI) was performed to determine the degree of meniscal extrusion. Millimeters of extrusion and percentage of extruded meniscal tissue were calculated for both groups. The degree of extrusion was considered minor if it was 3 mm. Results: Group A had 11 cases (73.3%) of major extrusion and group B had 4 cases (28.6%) (p = 0.02). The percentage of extruded meniscal tissue was 35% in group A and 24.6% in group B (p = 0.04). At a mean 3.4 years (range 1-4) post-operatively, the Lysholm score had a mean 89.60 ± 6.93 and 91.43 ± 6.19 points in groups A and B, respectively (p < 0.001). The median follow-up Tegner score improved from 4 (range 3-5) to 7 (range 6-9) in group A (p < 0.001) and from 4 (range 3-5) to 7 (range 6-8) in group B (p < 0.001). VAS dropped 5 and 7.3 points in groups A and B, respectively (p < 0.001). There were no complications in this series. Conclusions: In lateral MAT with the suture-only fixation technique, the described capsulodesis minimized meniscal extrusion. In terms of functional results, there were no differences between the groups at a mean 3.4-year follow-up

Local infiltration analgesia adds no clinical benefit in pain control to peripheral nerve blocks after total knee arthroplasty.

PURPOSE: To evaluate the effect of the local infiltration of analgesics for pain after total knee arthroplasty in patients treated with femoral and sciatic peripheral nerve blocks. The secondary objective was to detect differences in analgesic consumption as well as blood loss after local infiltration of analgesics. METHODS: Prospective randomized double-blinded study in patients who underwent a TKA for knee osteoarthritis under spinal anesthesia and treated with femoral and sciatic nerve blocks. This study compared 50 patients treated with local infiltration with ropivacaine, epinephrine, ketorolac and clonidine and 50 patients treated with a placebo with the same technique. The visual analogic score was registered postoperatively at 2, 6, 12, 24, 36, 48 and 72 h after surgery. Analgesic consumption was also registered. Both groups of patients were treated with the same surgical and rehabilitation protocols. RESULTS: A significant difference of one point was found in the visual analogic pain scores 12 h after surgery (0.6 ± 1.5 vs. 1.7 ± 2.3). There were no significant differences in the visual analogic pain scores evaluated at any other time between 2 and 72 h after surgery. No significant differences were found in the required doses of tramadol or morphine in the postoperative period. Postoperative hemoglobin and blood loss were also similar in both groups. CONCLUSION: Adding local infiltration of analgesics to peripheral nerve blocks after TKA surgery only provides minimal benefit for pain control. This benefit may be considered as non-clinically relevant. Moreover, the need for additional analgesics was the same in both groups. Therefore, the use of local infiltration of analgesics treatment in TKA surgery cannot be recommended if peripheral nerve blocks are used

C-reactive protein may misdiagnose prosthetic joint infections, particularly chronic and low-grade infections

BACKGROUND: Periprosthetic tissue cultures, sonication and synovial fluid cultures remain the gold standard for prosthetic joint infection (PJI) diagnosis. However, some 15-20% culture-negative PJI are still reported. Therefore, there is the need for other diagnostic criteria. One point of concern relative to the different definitions of PJI is as to the inclusion of the c-reactive protein (CRP) and the erythrocyte sedimentation rate (ESR) as diagnostic criteria for PJI despite them being non-specific inflammatory blood tests. PURPOSE: The purpose of the present study was to determine the relevance of CRP and the ESR in the diagnosis of PJI. METHODS: All PJI with positive cultures over a two-year period in two hospitals were reviewed. The main variables of the present study were the type of prosthesis and the CRP level. More information was recorded in those patients with normal CRP: radiographs, physical examination records and the ESR. RESULTS: Seventy-three patients were included in study. Pre-operative CRP levels were normal (lower than 0.8 mg/dl) in 23 patients, representing 32% of all PJI with positive cultures. Low virulence micro-organisms, 12 coagulase-negative staphylococci and four P. acnes, grew in most of them. They represented 70% of all PJI with normal CRP levels. In addition, 17 patients (23% of all PJI with positive cultures) had a normal ESR, a normal physical examination (they only presented with pain) and no clear loosening was observed in the radiographs. CONCLUSIONS: Per the American Association of Orthopaedic Surgeons (AAOS) guidelines or the Musculoskeletal Infection Society (MSIS), 23% of the patients in the present study with PJI would never have been identified. Blood inflammatory markers such as the CRP level and ESR may not be accurate as diagnostic tools in PJI, particularly to identify low-grade and chronic PJI