Influence of Human Bone Marrow Mesenchymal Stem Cells Secretome from Acute Myeloid Leukemia Patients on the Proliferation and Death of K562 and K562-Lucena Leukemia Cell Lineages.

Leukemias are among the most prevalent types of cancer worldwide. Bone marrow mesenchymal stem cells (MSCs) participate in the development of a suitable niche for hematopoietic stem cells, and are involved in the development of diseases such as leukemias, to a yet unknown extent. Here we described the effect of secretome of bone marrow MSCs obtained from healthy donors and from patients with acute myeloid leukemia (AML) on leukemic cell lineages, sensitive (K562) or resistant (K562-Lucena) to chemotherapy drugs. Cell proliferation, viability and death were evaluated, together with cell cycle, cytokine production and gene expression of ABC transporters and cyclins. The secretome of healthy MSCs decreased proliferation and viability of both K562 and K562-Lucena cells; moreover, an increase in apoptosis and necrosis rates was observed, together with the activation of caspase 3/7, cell cycle arrest in G0/G1 phase and changes in expression of several ABC proteins and cyclins D1 and D2. These effects were not observed using the secretome of MSCs derived from AML patients. In conclusion, the secretome of healthy MSCs have the capacity to inhibit the development of leukemia cells, at least in the studied conditions. However, MSCs from AML patients seem to have lost this capacity, and could therefore contribute to the development of leukemia.

Revisiting the role of hyperbaric oxygen therapy in knee injuries: Potential benefits and mechanisms.

Knee injury negatively impacts routine activities and quality of life of millions of people every year. Disruption of tendons, ligaments, and articular cartilage are major causes of knee lesions, leading to social and economic losses. Besides the attempts for an optimal recovery of knee function after surgery, the joint healing process is not always adequate given the nature of intra-articular environment. Based on that, different therapeutic methods attempt to improve healing capacity. Hyperbaric oxygen therapy (HBOT) is an innovative biophysical approach that can be used as an adjuvant treatment post-knee surgery, to potentially prevent chronic disorders that commonly follows knee injuries. Given the well-recognized role of HBOT in improving wound healing, further research is necessary to clarify the benefits of HBOT in damaged musculoskeletal tissues, especially knee disorders. Here, we review important mechanisms of action for HBOT-induced healing including the induction of angiogenesis, modulation of inflammation and extracellular matrix components, and activation of parenchyma cells-key events to restore knee function after injury. This review discusses the basic science of the healing process in knee injuries, the role of oxygen during cicatrization, and shed light on the promising actions of HBOT in treating knee disorders, such as tendon, ligament, and cartilage injuries.

Thromboprophylaxis with unilateral pneumatic device led to less edema and blood loss compared to enoxaparin after knee arthroplasty: randomized trial.

BACKGROUND: Pharmacological and mechanical thromboprophylaxis are frequently used together after total knee arthroplasty (TKA). Most studies in this context compare anticoagulants versus a combination of these drugs with an intermittent pneumatic compression device (IPCD). However, there is uncertainty about the need for the combination of both and whether a unilateral IPCD would alone affect other important clinical outcomes: edema and blood loss. We compared the effects of enoxaparin versus unilateral portable IPCD after TKA on edema and blood loss. We hypothesised that unilateral IPCD would cause the same level of edema and the same blood loss as enoxaparin. METHODS: In this open, randomized trial (1:1), adults with no history of coagulation disorders, anticoagulant use, venous thromboembolism, liver or malignant diseases underwent TKA. For 10 days, participants received the IPCD, used 24 h/day on the operated leg from the end of surgery, or 40 mg of enoxaparin, starting 12 h after surgery. All underwent the same rehabilitation and were encouraged to walk on the same day of surgery. We measured edema (thigh, leg and ankle circumference) before and on the third postoperative day. Blood loss (volume accumulated in the suction drain and drop of hemoglobin and hematocrit in 48 h) was a secondary outcome. RESULTS: We randomized 150 patients and lost 3 to follow-up with enoxaparin and 2 with IPCD. There was no case of symptomatic venous thromboembolism. Four patients needed transfusions (three receiving enoxaparin), one had infection and one hemarthrosis (both in the enoxaparin group). Leg circumference increased by approximately 2 cm for enoxaparin group and 1.5 cm in IPCD (p <  0.001). The increase in ankle circumference was about 1.5 cm in the enoxaparin group (p <  0.001), and almost zero in IPCD (p = 0.447). Enoxaparin group lost 566.1 ml (standard deviation, SD, 174.5) of blood in the first 48 h, versus 420.8 ml (SD 142.5) in the IPCD. CONCLUSIONS: Exclusively mechanical prophylaxis after TKA with portable IPCD only on the operated leg reduces leg and ankle swelling and post-operative blood loss compared to exclusively pharmacological prophylaxis with enoxaparin. Portable devices that can prevent deep vein thrombosis and pulmonary embolism without increasing blood loss or other risks should be further investigated. TRIAL REGISTRATION: REBEC RBR-8k2vpx. Registration date: 06/04/2019.

The use of negative-pressure wound therapy after total knee arthroplasty is effective for reducing complications and the need for reintervention.

BACKGROUND: Wound healing complications are causal factors of prosthesis infection and poor postoperative evolution of patients after total knee arthroplasty (TKA). Negative-pressure wound therapy (NPWT) can be an option to minimize these complications. The aim of this study is to compare the complications of patients undergoing TKA who used a portable NPWT device in the immediate postoperative period with those of a control group. METHODS: A total of 296 patients were evaluated. Patients were divided into two groups: those who used NPWT for seven days in the postoperative period (Group 1 - prospective evaluated) and those who used conventional dressings (Group 2 - historical control group). Epidemiological data, comorbidities, local parameters related to the surgical wound and complications were evaluated. RESULTS: The groups did not differ in regard to sex, age and clinical comorbidities. Overall, 153 (51.7%) patients had at least one risk factor for wound complications. Patients who used NPWT had a lower rate of complications (28.5% vs. 45.7%, p = 0.001) and a lower rate of reintervention in the operating room (2% vs. 8.5%, p = 0.001). Patients in group 1 had a lower incidence of hyperaemia (14.7% vs. 40.2%, p = 0.01), skin necrosis (2.1% vs. 8.5%, p = 0.04) and wound dehiscence (3.1% vs 10.1%, p = 0.03). The use of NPWT was a protective factor for the presence of complications, with an odds ratio of 0.36 (95% CI 0.206-0.629). CONCLUSION: The number of complications related to the wound after TKA is high; however, most of them are minor and have no impact on the treatment and clinical evolution of patients. The use of NPWT decreased the number of surgical wound complications, especially hyperaemia, dehiscence and necrosis, and reduced the need for reintervention.

Growth Factor Delivery to a Cartilage-Cartilage Interface Using Platelet-Rich Concentrates on a Hyaluronic Acid Scaffold.

PURPOSE: To determine whether (1) human leukocyte-platelet-rich plasma (L-PRP) or (2) leukocyte-platelet-rich fibrin (L-PRF) delivered on a hyaluronic acid (HA) scaffold at a bovine chondral defect, a simulated cartilage tear interface, in vitro would improve tissue formation based on biomechanical, histologic, and biochemical measures. METHODS: L-PRF and L-PRP were prepared from 3 healthy volunteer donors and delivered in conjunction with HA scaffolds to defects created in full-thickness bovine cartilage plugs harvested from bovine femoral condyle and trochlea. Specimens were cultured in vitro for up to 42 days. Treatment groups included an HA scaffold alone and scaffolds containing L-PRF or L-PRP. Cartilage repair was assessed using biomechanical testing, histology, DNA quantification, and measurement of sulfated glycosaminoglycan and collagen content at 28 and 42 days. RESULTS: L-PRF elicited the greatest degree of defect filling and improvement in other histologic measures. L-PRF-treated specimens also had the greatest cellularity when compared with L-PRP and control at day 28 (560.4 µg vs 191.4 µg vs 124.2 µg, P = .15); at day 48, there remained a difference, although not significant, between L-PRF versus L-PRP (761.1 µg vs 589.3 µg, P = .219) . L-PRF had greater collagen deposition when compared with L-PRP at day 42 (40.1 µg vs 16.3 µg, P < .0001). L-PRF had significantly greater maximum interfacial strength compared with the control at day 42 (10.92 N vs 0.66 N, P = .015) but had no significant difference compared with L-PRP (10.92 N vs 6.58 N, P = .536). L-PRP facilitated a greater amount of sulfated glycosaminoglycan production at day 42 when compared with L-PRF (15.9 µg vs 4.3 µg, P = .009). CONCLUSIONS: Delivery of leukocyte-rich platelet concentrates in conjunction with a HA scaffold may allow for improvements in cartilage healing through different pathways. L-PRF was not superior to L-PRP in its biomechanical strength, suggesting that both treatments may be effective in improving biomechanical strength of healing cartilage through different pathways. CLINICAL RELEVANCE: The delivery of platelet-rich concentrates in conjunction HA scaffolds may augment healing cartilaginous injuries.

Clinical results of pulsed signal therapy on patellofemoral syndrome with patellar chondropathy.

This study was designed to evaluate the effect of pulsed signal therapy (PST) on patellofemoral pain syndrome associated with patellar chondropathy. A prospective randomized double-blind placebo controlled trial included 25 patients (41 knees) between 20 and 50 years with pain due to isolated patellofemoral syndrome with chondropathy. PST group received nine 60-min daily sessions of PST treatment. Control group received the same protocol of blinded placebo treatment. The main outcome was change from baseline Kujala score at 3 months. After 3 months, patients in the control group received effective treatment (placebo post-treatment). All patients were then followed, for up to 12 months. Seventeen knees (5 males and 12 females, mean age 36.7 ± 7.9) received placebo and 24 knees (8 males and 16 females, mean age 35.5 ± 8.9) received PST. By the third month, PST group exhibited a mean change from baseline of 9.63 ± 7.5 Kujala points, compared to 0.53 ± 1.8 in the placebo group (P < 0.001). A significant progressive improvement was seen in the PST group between the 3rd and 6th and between the 6th and 12th month (P < 0.016). Patients initially allocated in the control group also improved at 3 months (P < 0.001) and 6 months (P = 0.005) post-effective treatment. In conclusion, PST in patellofemoral pain syndrome with chondropathy was effective compared to placebo at 3 months, showing an important improvement of Kujala score. The improvement was progressive and maintained up to 12 months. PST is safe and should be considered as a non-invasive option for management of this condition. Bioelectromagnetics. 40:83-90, 2019. © 2019 Bioelectromagnetics Society.

Combined Reconstruction of the Anterolateral Ligament in Patients With Anterior Cruciate Ligament Injury and Ligamentous Hyperlaxity Leads to Better Clinical Stability and a Lower Failure Rate Than Isolated Anterior Cruciate Ligament Reconstruction.

PURPOSE: To compare functional outcomes, residual instability, and rupture rates in patients with ligamentous hyperlaxity undergoing isolated anterior cruciate ligament (ACL) reconstruction or combined ACL and anterolateral ligament (ALL) reconstruction. METHODS: Two groups of patients were evaluated and compared retrospectively. Both groups consisted of patients with ACL injuries and associated ligamentous hyperlaxity, defined based on the modified Beighton scale with a minimum score of 5. Group 1 patients underwent anatomical ACL reconstruction, and group 2 patients underwent anatomical ACL reconstruction combined with ALL reconstruction. Group 1 consisted of historical controls. The presence of associated meniscal injury, subjective International Knee Documentation Committee and Lysholm functional scores, KT-1000 measurements, the presence of a residual pivot-shift, and the graft rupture rate were evaluated. The study was performed at University of São Paulo in Brazil. RESULTS: Ninety patients undergoing ACL reconstruction with ligamentous hyperlaxity were evaluated. The mean follow up was 29.6 ± 6.2 months for group 1 and 28.1 ± 4.2 months for group 2 (P = .51). No significant differences were found between the groups regarding Beighton scale, gender, the duration of injury before reconstruction, follow-up time, preoperative instability, or associated meniscal injuries. The mean age was 29.9 ± 8.1 years in group 1 and 27.0 ± 9.1 years in group 2 (P = .017). In the final evaluation, group 2 patients showed better anteroposterior clinical stability as evaluated by KT-1000 arthrometry (P = .02), better rotational stability as evaluated by the pivot-shift test (P = .03) and a lower reconstruction failure rate (21.7% [group 1] vs 3.3% [group 2]; P = .03). Clinical evaluations of postoperative functional scales showed no differences between the 2 groups (P = .27 for International Knee Documentation Committee; P = .41 for Lysholm). CONCLUSIONS: Combined ACL and ALL reconstruction in patients with ligamentous hyperlaxity resulted in a lower failure rate and improved knee stability parameters compared to isolated ACL reconstruction. No differences were found in the functional scales. LEVEL OF EVIDENCE: Level III, case control study.

Evaluation of Posterior Cruciate Ligament and Intercondylar Notch in Subjects With Anterior Cruciate Ligament Tear: A Comparative Flexed-Knee 3D Magnetic Resonance Imaging Study.

PURPOSE: To determine if posterior cruciate ligament (PCL) and intercondylar notch (IN) morphometries and volumetrics act as risk factors for anterior cruciate ligament (ACL) tears. METHODS: A prospective case-controlled magnetic resonance imaging (MRI) study was conducted with subjects presenting noncontact knee injuries. Exclusion criteria were previous surgery, PCL tear, osteoarthritis, tumors, or infectious and inflammatory conditions. All participants underwent a flexed-knee 3-dimensional (3D) magnetic resonance imaging (MRI) to uniformly straighten PCL. MR images were independently reviewed by 2 radiologists and assessed for 2D and 3D measurements (bicondylar width; IN angle, depth, width, and cross-sectional area; PCL width, thickness, and cross-sectional area; and IN and PCL volumes). Clinical profiles were tabulated and subjects were divided into cases (ACL tear) and controls (without ACL tear). RESULTS: The study was composed of 50 cases versus 52 controls (N = 102), with a mean age of 36.8 years. There was no difference between groups (P > .05) regarding age, gender, body mass index, time from injury, Tegner score, flexion angle, limb side, intensity of injury, or familial or opposite limb history of tear. Agreement between readers ranged from substantial to almost perfect. Subjects with ACL tear presented with lower IN width, lower IN minus PCL widths, lower Notch Width Index, higher PCL/IN width proportion, higher PCL thickness, lower IN depth minus PCL thickness, and higher PCL thickness/IN depth proportion (P < .05). Moreover, higher PCL/IN cross-sectional area proportion, higher PCL volumes (OR = 9.01), and higher PCL/IN volume proportion were also found in cases. CONCLUSIONS: Our study shows that subjects with ACL tears present not only reduced IN but also larger PCL dimensions. These findings, isolated and combined, and especially PCL volume, might be suggestive as risk factors for ACL tears owing to the reduction of its space inside the IN. LEVEL OF EVIDENCE: Level III, comparative group.

Combined reconstruction of the anterolateral ligament in chronic ACL injuries leads to better clinical outcomes than isolated ACL reconstruction.

PURPOSE: To evaluate the results of combined anterior cruciate ligament (ACL) and anterolateral ligament (ALL) reconstruction in patients with chronic ACL injury. It was hypothesized that patients who underwent combined ACL and ALL reconstruction would exhibit less residual laxity and better clinical outcomes. METHODS: Two groups of patients were evaluated and compared retrospectively. Both groups consisted only of patients with chronic (more than 12 months) ACL injuries. Patients in group 1 underwent anatomical intra-articular reconstruction of the ACL and patients in group 2 underwent anatomic intra-articular ACL reconstruction combined with ALL reconstruction. The presence of associated meniscal injury, the subjective International Knee Documentation Committee (IKDC) and Lysholm functional outcome scores in the postoperative period, KT-1000 evaluation, the presence of residual pivot shift and graft rupture rate were evaluated. RESULTS: One hundred and one patients who underwent reconstruction of chronic ACL injuries were evaluated. The median follow-up was 26 (24-29) months for group 1 and 25 (24-28) months for group 2. There were no significant differences between groups regarding gender, age, duration of injury until reconstruction, follow-up time or presence of associated meniscal injuries in the preoperative period. Regarding functional outcome scores, patients in group 2 presented better results on both the IKDC (p = 0.0013) and the Lysholm (p < 0.0001) evaluations. In addition, patients in group 2 had better KT-1000 evaluation (p = 0.048) and a lower pivot shift rate at physical examination, presenting only 9.1% positivity versus 35.3% in the isolated ACL reconstruction (p = 0.011). Regarding re-ruptures, group 1 presented 5 (7.3%) cases, and group 2 presented no cases. CONCLUSION: The combined ACL and ALL reconstruction in patients with chronic ACL injury is an effective and safety solution and leads to good functional outcomes with no increase in complication rate. The clinical relevance of this finding is the possibility to indicate this type of procedure when patients present with more than 12 months after injury for surgery. LEVEL OF EVIDENCE: Level III.

Histopathological analysis of the posterior cruciate ligament in primary osteoarthritis.

BACKGROUND: According to some authors, the indication of an arthroplasty maintaining the posterior cruciate ligament (PCL) demands adequate structural preservation and proprioceptive function of this ligament. The nervous fibers contained in the synovial neurovascular bundle (NVB) around the PCL are involved in proprioception. A study evaluating the grade of PCL and NVB degeneration by using clinical, radiological, and perioperative parameters in knee arthritis patients, in theory, could help surgeons in the decision of preserving or not preserving the PCL in a particular patient. QUESTIONS: (1) Can the degree of the PCL collagen fibers degeneration be predicted by clinical, radiographic, and perioperative parameters in knee arthritis patients? (2) Is the NVB histological degeneration status predictable using clinical, radiographic, and perioperative parameters in the same subset of patients? (3) Is there a correlation between the degree of the PCL collagen fibers degeneration and NVB status in knee arthritis patients? METHODS: Eighty-nine PCLs (85 patients) obtained from total knee replacement surgery were studied. The histologic degeneration of PCL collagen fibers and the NVB status (preserved, degenerated, not detected) were evaluated. These histological degeneration patterns were correlated with clinical and radiographic parameters and with anterior cruciate ligament (ACL) status. RESULTS: A small prevalence of preserved NVB was related to Grades IV and V of Ahlbäck's classification, ACL absence, and severe PCL degeneration. The clinical and radiological parameters studied were not able to predict the grade of histological degeneration of the PCL. CONCLUSIONS: Ahlbäck's classification and ACL status provided useful information about NVB integrity. LEVEL OF EVIDENCE: Basic Science Level IV.

Assessment of the Anterolateral Ligament of the Knee by Magnetic Resonance Imaging in Acute Injuries of the Anterior Cruciate Ligament.

PURPOSE: To evaluate the epidemiology of injuries and abnormalities of the anterolateral ligament (ALL) by magnetic resonance imaging (MRI) in cases of acute anterior cruciate ligament (ACL) injury. METHODS: MRIs of patients with acute ACL injury were evaluated. Acute injuries of the ACL were considered in cases in which the patient reported knee trauma occurring less than 3 weeks prior and when bone bruise in the femoral condyles and tibial plateau was identified. ALL abnormality was considered when it showed proximal or distal bone detachment, discontinuity of fibers, or irregular contour associated with periligamentous edema. The ALL was divided into femoral, tibial, and meniscal portions, and the lesions and/or abnormalities of each portion were characterized. The correlation of ALL injury with injuries of the lateral meniscus was evaluated. RESULTS: A total of 101 MRIs were initially evaluated. The ALL was not characterized in 13 (12.8%) examinations, resulting in 88 (87.1%) cases of injury evaluation. Of these, 55 (54.4%) patients had a normal ALL, and 33 (32.6%) showed signs of injury. Among the cases with injury, 24 (72%) patients showed proximal lesions, 7 (21%) showed distal lesions, and 2 (6.0%) patients presented both proximal and distal lesions. The meniscal portion of the ALL appeared abnormal in 16 (48%) patients. No relationship was found between ALL injury and lateral meniscus injury. CONCLUSIONS: Based on MRI analysis of acute ACL injuries with bone bruising of the lateral femoral condyle and lateral tibial plateau, approximately a third demonstrated ALL injuries of which the majority was proximal. LEVEL OF EVIDENCE: Level IV, case series.

Medial Patellofemoral Ligament, Medial Patellotibial Ligament, and Medial Patellomeniscal Ligament: Anatomic, Histologic, Radiographic, and Biomechanical Study.

PURPOSE: To describe the anatomy (quantitative macroscopic and histologic), radiographic parameters of the insertions, and biomechanical characteristics of the medial ligamentous restrictors of the patella (medial patellofemoral ligament [MPFL], medial patellotibial ligament [MPTL], and medial patellomeniscal ligament [MPML]) in cadaveric knees. Because the MPTL and the MPML are not as well known as the MPFL, they were the focus of this study. METHODS: MPFLs, MPTLs, and MPMLs from 9 knees were dissected. Histologic evaluations were conducted. Length, width, and insertion relations with anatomic references were determined. Metallic spheres were introduced into the insertion points of each ligament, and anteroposterior and lateral radiographs were taken. The distances of the insertions from the baselines were measured on radiographs. Tensile tests of the ligaments were performed. RESULTS: All the samples showed dense connective tissue characteristic of ligaments. The MPTL was inserted into the proximal tibia (13.7 mm distal to the joint line) and in the distal end of the patella (3.6 mm proximal to the distal border). The MPTL had a length of 36.4 mm and a width of 7.1 mm. The MPML was inserted into the medial meniscus and distally in the patella (5.7 mm proximal to the distal border). Per radiography, on the anteroposterior view, the tibial insertion of the MPTL was 9.4 mm distal to the joint line and in line with the medial border of the medial spine. On the lateral view, the patellar insertions of the MPTL and MPML were 4.8 and 6.6 mm proximal to its distal border, respectively. The MPTL was stiffer than the MPFL (17.0 N/mm vs 8.0 N/mm, P = .024) and showed less deformation in the maximum tensile strength (8.6 mm vs 19.3 mm, P = .005). CONCLUSIONS: The MPTL inserts into the proximal tibia and into the distal pole of the patella. The MPML inserts into the medial meniscus and into the distal pole of the patella. They present with identifiable anatomic and radiographic parameters. Grafts commonly used for ligament reconstructions should be adequate for reconstruction of the MPTL. CLINICAL RELEVANCE: The study contributes to the anatomic, radiographic, and biomechanical knowledge of the MPTL to improve the outcomes of its reconstruction.

Anterolateral ligament abnormalities are associated with peripheral ligament and osseous injuries in acute ruptures of the anterior cruciate ligament.

PURPOSE: Few studies have used MRI to identify the ALL. As it was shown that it is not possible to precisely characterize this ligament in all examination, it is important to identify concomitant lesions that can help in diagnosing ALL abnormalities. It is important to characterise this injury due to its association with anterolateral knee instability. Thus, the present study was performed to determine the frequency of ALL injuries in patients with acute ACL rupture and to analyse its associated knee lesions. METHODS: Patients with acute ACL injuries were evaluated by MRI. Among this population, the ALL was classified as non-visualised, injured or normal. The possible abnormalities of the meniscus, collateral ligaments, popliteus tendon, posterior cruciate ligament, Iliotibial band (ITB), anterolateral capsule and osseus injuries were evaluated. The association of an ALL injury with these other knee structures as well as sex and age was calculated. RESULTS: Among the 228 knees evaluated, the ALL could not be entirely identified in 61 (26.7%). Of the remaining 167, 66 (39.5%) presented an ALL abnormality and only four (6.1%) were Segond fractures. ALL abnormalities were associated with lesions of the lateral collateral ligament, medial collateral ligament, popliteus tendon, ITB, anterolateral capsule and osseous contusions of the femoral condyle and tibial plateau. No correlation was found with medial meniscus, lateral meniscus and posterior cruciate ligament injuries. There was no association between ALL injuries and gender, and older patients were more likely to present an ALL injury. CONCLUSION: ALL injuries are present in approximately 40% of ACL injuries, and a minority of these are Segond fractures. These injuries are associated with peripheral ligament injuries, anterolateral structures lesions and bone contusions, but there is no association with meniscal injuries. Surgeons must be aware of these associations to consider an ALL lesion even if it is not completely clear in imaging evaluation, especially if a high degree of anterolateral instability is present on physical examination. LEVEL OF EVIDENCE: III.

Why are bone and soft tissue measurements of the TT-TG distance on MRI different in patients with patellar instability?

PURPOSE: To determine whether the tibial tuberosity-to-trochlear groove distance (TT-TG) and patellar tendon-to-trochlear groove distance (PT-TG) are equal, whether the bony and cartilaginous points coincide in the trochlea, and whether the insertion of the PT coincides with the most anterior point of the TT in patients with patellar instability. METHODS: Fifty-three MRI scans of patients with patellar instability were examined. TT-TG and PT-TG were measured by three examiners in 31 knees. Additionally, the bone-cartilage distance in the trochlea [trochlear cartilage to trochlear bone (TC-TB)] and the distance between the mid-point of the PT insertion and the most anterior point of the TT (PT-TT) were measured by one examiner. The intraclass correlation coefficient was used to evaluate the reliability of the measurements between the three examiners. The relationships between the measurements were determined, the means of the measurements were calculated, and the correlations between PT-TG and TT-TG, PT-TT, and TC-TB were assessed. RESULTS: The ICC was above 0.8. PT-TG was 3.7 mm greater than TT-TG. The TC and TB coincided in 73 % of cases, and the mean TC-TB was 0.3 mm. The PT was lateral to the TT in 94 % of the cases, and the mean PT-TT was 3.4 mm. The Pearson's correlation coefficients between PT-TG and TT-TG, PT-TT, and TC-TB were 0.946, 0.679, and 0.199, respectively. CONCLUSION: TT-TG underestimated PT-TG, primarily due to the lateralization of the PT insertion relative to the most anterior point of the TT. CLINICAL RELEVANCE: our study shows that in patients with patellar instability, there are differences in the absolute values of TT-TG and PT-TG, as previously reported for patients without patellar instability. Hence, normal cut-off values based on case-control studies of TT-TG cannot be equivalently used when measuring PT-TG to indicate TT medialization in patients with patellar instability. It is also important to note that the clinical outcomes cannot be directly compared between patients evaluated using TT-TG versus PT-TG measurements. LEVEL OF EVIDENCE: III.

Combined reconstruction of the posterior cruciate ligament and medial collateral ligament using a single femoral tunnel.

PURPOSE: Lesions of the medial collateral ligament (MCL) are the most common knee ligament injuries, and lesions associated with the anterior cruciate ligament or the posterior cruciate ligament (PCL) in knee dislocations should be reconstructed to prevent failure of the central pivot reconstruction. The purpose of this study was to evaluate the outcomes of combined PCL/MCL reconstruction using a single femoral tunnel with a minimum 2-year follow-up. METHOD: A retrospective study of thirteen patients with combined PCL/MCL injuries was conducted. The patients underwent PCL and MCL reconstruction using an Achilles tendon allograft with a single tunnel in the medial femoral condyle, thereby avoiding tunnel conversion. RESULTS: All patients achieved a range of motion of at least 100°. The mean loss of extension and flexion values compared to the contralateral side was 1° ± 2° and 9° ± 10°, respectively. Our results included 26 reconstructions with three (11.5 %) failures, two in the PCL (15.3 %) and one in the MCL (7.6 %), in three different patients. In the final evaluation, the mean IKDC subjective score was 71.63 ± 16.23, the mean Lysholm score was 80.08 ± 13.87, and the median Tegner score was 6 (range = 2-7). CONCLUSION: The PCL/MCL reconstruction technique using a single femoral tunnel and an Achilles tendon allograft is safe, avoids the convergence of tunnels in the medial femoral condyle, has excellent results, and is reproducible. LEVEL OF EVIDENCE: IV.

Patellar tracking after isolated medial patellofemoral ligament reconstruction: dynamic evaluation using computed tomography.

PURPOSE: Medial patellofemoral ligament (MPFL) reconstruction offers good clinical results with a very low rate of instability recurrence. However, its in vivo effect on patellar tracking is not clearly known. The aim of this study is to investigate the effects of MPFL reconstruction on patellar tracking using dynamic 320-detector-row CT. METHODS: Ten patients with patellofemoral instability referred to isolated MPFL reconstruction surgery were selected and subjected to dynamic CT before and ≥6 months after surgery. Patellar tilt angles and shift distance were analysed using computer software specifically designed for this purpose. Kujala and Tegner scores were applied, and the radiation of the CTs was recorded. Two protocols for imaging acquisition were compared: a tube potential of 80 kV and 50 mA versus a tube potential of 120 kV and 100 mA, both with a slice thickness of 0.5 mm and an acquisition duration of 10 s. RESULTS: There were no changes in patellar tracking after MPFL reconstruction. There was no instability relapse. Clinical scores improved from a mean of 51.9 (±15.6)-74.2 (±20.9) on the Kujala scale (p = 0.011) and from a median of 2 (range 0-4) to 4 (range 1-6) on the Tegner scale (p = 0.017). The imaging protocols produced a dose-length product (DLP) of 254 versus 1617 mGycm and a radiation effective estimated dose of 0.2 versus 1.3 mSv, respectively. Both protocols allowed the analysis of the studied parameters without loss of precision. CONCLUSIONS: Reconstruction of the MPFL produced no improvement in patellar tilt or shift in the population studied. The low-radiation protocol was equally effective in measuring changes in patellar tracking and is recommended. Although the procedure successfully stabilized the patella, knee surgeons should not expect patellar shift and tilt correction when performing isolated patellofemoral ligament reconstruction in patients with recurrent patellar instability. LEVEL OF EVIDENCE: IV.

Biomechanical study of strength and stiffness of the knee anterolateral ligament.

BACKGROUND: Recent studies clearly characterize the anatomical parameters of the knee anterolateral ligament (ALL). The potential clinical importance of this ligament is exemplified by some patients with possible combined Anterior Cruciate Ligament (ACL) and ALL rupture who do not progress satisfactorily following isolated ACL reconstruction. Previous biomechanical studies have assessed the resistance parameters of the ALL in order to address potential reconstruction strategies; however, these have reported conflicting results. Thus, this study aimed to evaluate the linear resistance of the ALL by means of a biomechanical study in cadaveric knees. METHODS: Fourteen cadaveric knees were used. The ALL was dissected, and all structures that connect the femur and the tibia, except for the ALL, were sectioned. The ALL was subjected to a tensile test with the knee around 30 to 40 degrees, in a way that the ALL was aligned with the machine. The strength at the maximum resistance limit, deformation and stiffness of the ALL were evaluated. RESULTS: The mean maximum strength of the ALL was 204.8 +/- 114.9 N. The stiffness was 41.9 +/- 25.7 N/mm and the deformation 10.3 +/- 3.5 mm. CONCLUSION: The ALL has a mean ultimate tensile strength of 204.8 N. This suggests that simple bands of all autologous or homologous grafts commonly used in clinical practice for ligament reconstruction around the knee possess the required biomechanical resistance characteristics for ALL reconstruction.

"Fatigue meniscal tears": a description of the lesion and the results of arthroscopic partial meniscectomy.

PURPOSE: The purpose of this study was to describe the clinical outcomes of partial meniscectomy in patients with "fatigue meniscal tear", which presents as a non-traumatic tear with abrupt onset of symptoms of a radial tear in the transition between the middle and posterior thirds of the meniscus. METHODS: We prospectively followed 71 patients with "fatigue meniscal tear" (41 women and 30 men, mean age of 63 years, SD 6.9 years) recruited among 497 patients with isolated medial meniscal lesions treated between January 2006 and June 2011. Inclusion criteria were spontaneous abrupt onset knee pain, minor or no trauma, no radiographic or MRI osteoarthritis, no bone oedema, pre-operative magnetic resonance image of medial meniscus tear, and arthroscopic evaluation demonstrating radial or vertical flap tear in the body to posterior horn junction of the medial meniscus. We followed all patients for a minimum of two years and reviewed their clinical symptoms, physical exam, functional outcome, and patient satisfaction at last follow-up. RESULTS: The average follow-up was 4.2 years, with a minimum follow-up of two years. Among the 71 patients, there were 59 (83.1 %) good or excellent results and 12 (16.9 %) poor results. These 12 patients demanded further treatment because of persistent pain, with three of the patients developing subchondral bone fracture. All patient complaints and poor outcomes could be identified in the initial six months after surgery. There was no gender difference in the subgroup analysis. CONCLUSION: Our findings indicate that patients with "fatigue meniscal tear" benefit from arthroscopic partial meniscectomy, with only 16.9 % reporting unfavourable results. LEVEL OF EVIDENCE: IV, Cohort study or case series.

Is it safe to reconstruct the knee Anterolateral Ligament with a femoral tunnel? Frequency of Lateral Collateral Ligament and Popliteus Tendon injury.

PURPOSE: This study sought to determine the safety limits for performing a femoral bone tunnel to reconstruct the knee anterolateral ligament (ALL) by establishing its distance from the lateral collateral ligament (LCL) and the popliteus muscle tendon (PT) on the lateral femoral condyle. METHODS: Anatomic study on 48 knee cadaveric specimens. The femoral attachments of the studied structures were isolated, and the distance between them was measured. For each cadaver, the percentage of cases in which at least 50 % of the LCL and PT would be injured when using 4- to 12-mm-diameter drills in an ALL reconstruction procedure was evaluated. RESULTS: The LCL and PT were 3.8 mm and 10.2 mm distant from the ALL, respectively. A 4-mm tunnel would cause LCL injury in 8.3 % of cases, with increasing incidence of injury up to 87.5 % with a 12-mm drill. Injury to the PT would start with the 10-mm drill, causing injury in 2.0 % of cases. CONCLUSIONS: Performing a tunnel in the center of the ALL may cause an iatrogenic injury to the LCL origin. No cases of PT injury are expected to occur with drills smaller than 10 mm.

The meniscal insertion of the knee anterolateral ligament.

PURPOSE: The aim of this study is to characterize in detail the meniscal insertion of the anterolateral ligament (ALL) of the knee, establishing parameters regarding the circumference of the lateral meniscus and the popliteal muscle tendon (PMT) groove in addition to its histological analysis. METHODS: A total of 33 knees of cadavers were dissected. The ALL and the lateral meniscus were removed en bloc. After removal of the anatomical specimen, the meniscus circumference, the ALL insertion points on the external surface of the lateral meniscus, and the PMT groove were measured. Eight menisci were subjected to histological analysis. RESULTS: The ALL was found in all dissections performed. The ALL insertion occurred macroscopically in the transition between the anterior horn and the lateral meniscus body, specifically beginning at 36.0% and ending at 41.9% of the meniscal circumference, occupying a mean area of 5.6 mm. The distance between the end of the ALL meniscal insertion and the beginning of the PMT groove averaged 12.9 mm. In the histological evaluation, in longitudinal sections, we observed dense collagen fibers of the ligament inserting on the external surface of the meniscus. It is possible to observe a spreading of collagen fibers at the moment of meniscal insertion. CONCLUSIONS: The ALL meniscal insertion was found in all dissected specimens, beginning with approximately 36% of the meniscal outer diameter, 12.9 mm anterior to the beginning of the PMT groove. The histological analysis confirmed the presence of true ligamentous tissue in the dissected specimens.