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Ana Lucia Lei Munhoz Lima, Priscila Rosalba D de Oliveira, Perola Grimberg Plapler, Flora Maria D Andrea Marcolino, Eduardo de Souza Meirelles, André Sugawara, Riccardo Gomes Gobbi, Alexandre Leme Godoy dos Santos , Gilberto Luis CamanhoInstitute of Orthopedics and Traumatology, Hospital das Clínicas, University of São Paulo School of Medicine, São Paulo, BrazilAbstract: Increasing bone mineralization abnormalities observed among people living with HIV (PLWHIV) result from various factors relating to the host, the virus, and the antiretrovirals used. Today, HIV infection is considered to be a risk factor for bone mineralization disorders. The test most recommended for diagnosing osteoporosis is measurement of bone mineral density by means of dual energy X-ray absorptiometry at two sites. Osteoporosis treatment has the aims of bone mass improvement and fracture control. A combination of calcium and vitamin D supplementation may reduce the risk of fractures. Antiresorptive drugs act by blocking osteoclastic activity and reducing bone remodeling. On the other hand, bone-forming drugs stimulate osteoblastogenesis, thereby stimulating the formation of bone matrix. Mixed-action medications are those that are capable of both stimulating bone formation and inhibiting reabsorption. Antiresorptive drugs form the group of medications with the greatest quantity of scientific evidence confirming their efficacy in osteoporosis treatment. Physical activity is a health promotion strategy for the general population, but only preliminary data on its real value and benefit among PLWHIV are available, especially in relation to osteoporosis.Keywords: osteoporosis, HIV/AIDS, diagnosis, treatment, exercise

Objective: The objective of this study is to correlate clinical symptoms and functionality, using the KOOS (Knee Injury and Osteoarthritis Outcome Score) and KSS (Knee Society Score System) scores, with the radiographic changes, using the Kellgren-Lawrence classification, in patients with knee osteoarthritis and indications for Total Knee Arthroplasty (TKA)., Methods: 120 patients (189 knees) with gonarthrosis and indications for TKA were included in the study. Demographic questionnaires were applied, and clinical and functional assessment was carried out using the KOOS and KSS scores. Knee radiographs were taken and graded according to Kellgren-Lawrence. The clinical scores were compared with the radiographic classification to establish a correlation between these two measurements. Statistical analysis was performed using the τ-Kendall correlation test., Results: Weak and inversely proportional correlations were found between the clinical scores and the radiographic classification. Among clinical scores evaluated, KSS showed the highest correlation with Kellgren-Lawrence classification (τ = -0.356; p < 0.001), followed by KOOS-quality of life (τ = -0.176; p = 0.004), KOOS-total score (τ = -0.166; p = 0.004), KOOS-function in daily living (τ = -0.160; p = 0.005) and KOOS-symptoms (τ = -0.159; p = 0.006). KOOS-pain (τ = -0.149; p = 0.01) and KOOS-sport and recreation function (τ = -0.142; p = 0.025) scores had the weakest correlations., Conclusion: There is a weak correlation between the clinical-functional scores of TKA candidates and their radiographic classification by Kellgren-Lawrence. Among clinical scores evaluated, KSS had the strongest negative correlation with the radiographic classification., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest., (Copyright © 2024 HCFMUSP. Published by Elsevier España, S.L.U. All rights reserved.)

Objective: To propose a protocol for assessing knee instability in ACL-injured knees using weight-bearing computed tomography (WBCT)., Materials and Methods: We enrolled five patients with unilateral chronic ACL tears referred for WBCT. Bilateral images were obtained in four positions: bilateral knee extension, bilateral knee flexion, single-leg stance with knee flexion and external rotation, and single-leg stance with knee flexion and internal rotation. The radiation dose, time for protocol acquisition, and patients' tolerance of the procedure were recorded. A blinded senior radiologist assessed image quality and measured the anterior tibial translation (ATT) and femorotibial rotation (FTR) angle in the ACL-deficient and contralateral healthy knee., Results: All five patients were male, aged 23-30 years old. The protocol resulted in a 16.2 mGy radiation dose and a 15-min acquisition time. The procedure was well-tolerated, and patient positioning was uneventful, providing good-quality images. In all positions, the mean ATT and FTR were greater in ACL-deficient knees versus the healthy knee, with more pronounced differences observed in the bilateral knee flexion position. Mean lateral ATT in the flexion position was 9.1±2.8 cm in the ACL-injured knees versus 4.0±1.8 cm in non-injured knees, and mean FTR angle in the bilateral flexion position was 13.5°±7.7 and 8.6°±4.6 in the injured and non-injured knees, respectively., Conclusion: Our protocol quantitatively assesses knee instability with WBCT, measuring ATT and FTR in diverse knee positions. It employs reasonable radiation, is fast, well-tolerated, and yields high-quality images. Preliminary findings suggest ACL-deficient knees show elevated ATT and FTR, particularly in the 30° flexion position., (© 2024. The Author(s), under exclusive licence to International Skeletal Society (ISS).)

Purpose: To create a cut-off point for hyperextension that best discriminates retear and to verify whether this cut-off point can predict retear regardless of other characteristics after primary anterior cruciate ligament (ACL) reconstruction with hamstrings autograft., Methods: A cohort of patients submitted to primary isolated ACL reconstruction with hamstrings autografts was retrospectively evaluated. Patients were stratified according to the degree of passive knee hyperextension measured in the normal contralateral knee. The following data were collected: patient age and sex, time from injury to surgery, knee hyperextension, KT-1000 and pivot-shift, associated meniscus injury, intra-articular graft size, follow-up time, graft failure, and postoperative Lysholm and subjective International Knee Documentation Committee scores., Results: Data from 457 patients were evaluated. Median age was 31 years. Thirty-two (7.0%) presented with retear. There was a significant difference in hyperextension between patients with and without retear (P < .001), with the cut-off point established by the receiver operating characteristic curve from 6.5°. Patients with greater hyperextension had a statistically greater frequency of women, longer injury time, greater intra-articular graft diameter, greater postoperative KT-1000, and greater frequency of retear, whereas the subjective International Knee Documentation Committee and Lysholm scores were statistically lower in patients with greater hyperextension. Only hyperextension showed a statistically significant association with re-rupture (P < .001). The odds of retear in patients with hyperextension greater than 6.5 was 14.65 times the odds of patients with hyperextension less than 6.5., Conclusions: Patients with more than 6.5° of hyperextension are 14.6 times more likely to have a graft rupture than patients with lower hyperextension when submitted to ACL reconstruction with hamstring tendons. Also, they present worse knee stability by the KT-1000 test and worse functional outcomes. Therefore, patients with this degree of hyperextension should not have isolated reconstruction with hamstrings as their first choice., Level of Evidence: Level III, retrospective comparative prognostic trial., (Copyright © 2023 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

The reconstruction of the medial patellofemoral ligament (MPFL) is an essential procedure in the surgical treatment of patellar instability. The medial third of the patellar tendon is a good graft option for this reconstruction, maintaining the insertion of the graft in the patella, with no need for hardware for patellar fixation. The objective of this article is to describe the MPFL reconstruction technique with the patellar tendon graft., Competing Interests: The authors report no conflicts of interest in the authorship and publication of this article. Full ICMJE author disclosure forms are available for this article online, as supplementary material., (© 2024 The Authors.)

The peroneus longus tendon seems a viable graft option for knee ligament reconstructions, with adequate biomechanical properties and low morbidity after harvesting. The objective of this article is to describe a combined anterior cruciate ligament and anterolateral ligament reconstruction technique using a single peroneus longus tendon graft harvested from the infra malleolar region to ensure sufficient length., (© 2023 The Authors.)

Purpose: To describe, in controls and in a population with patellar instability, magnetic resonance imaging values of measurements representing major associated factors for patellar instability (patellar height, trochlear dysplasia, and extensor mechanism alignment), as well as their cutoff values., Methods: In total, 323 knee magnetic resonance imaging scans, 142 with patellar instability and 181 controls without patellofemoral complaints (anterior cruciate, medial collateral ligament, meniscus ruptures or normal) were evaluated. Means, normality values in the control population, ideal cutoff values through receiver operating characteristic curves analysis, and interobserver reliability (intraclass correlation coefficient) were described for a series of measurements., Results: All measurements were statistically different in control and instability patients, except for the patellotrochlear index and tibial tuberosity to posterior cruciate ligament distance. The interobserver intraclass correlation coefficient was good or excellent (above 0.75) only for the patellotrochlear index, patellar tendon-trochlear groove (PTTG) angle, and patellar tilt. The optimal cutoff value for each measurement was: PTTG angle ≥25.3 o with sensitivity (S) of 70% and specificity (E) of 89%, patellar tilt ≥16 o (S: 69% and E: 84%), trochlear sulcus angle ≥153 o (S: 75% and E: 76%), Carrillon ≤12.8 o (S: 62% and E: 87%), PTTG distance ≥11mm (S: 71% and E: 78%), Caton-Deschamps index ≥1.23 (S: 72% and E: 76%) and trochlear bump ≥3.95 mm (S: 76% and E: 65%)., Conclusions: Caton-Deschamps index (≥1.23), trochlear sulcus angle (≥153 o ), ventral prominence of the trochlea (≥3.95 mm), PTTG distance (≥11 mm), PTTG angle (≥25.3 o ), Carrillon angle (≤12.8 o ), and patellar tilt (≥16 o ) presented better diagnostic performance for patellar instability. Patellotrochlear index and tibial tuberosity to posterior cruciate ligament distance were not related to patellar instability. The interobserver reliability of the factors related to patellar instability was excellent only for the PTTG angle and lateral patellar tilt., Level of Evidence: Level III, retrospective case-control study., (Copyright © 2023 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Objective  To evaluate the incidence of symptomatic cyclops lesions requiring surgical treatment after anterior cruciate ligament (ACL) reconstruction and to establish possible intraoperative risk factors related to it. Methods  Three hundred and eighty-nine patients aged between 18 and 50 years who underwent primary ACL reconstruction were retrospectively evaluated. Patients were divided into groups according to the presence or absence of symptomatic cyclops lesions, and their characteristics were compared. Patients with associated lesions that required additional surgical procedures (except anterolateral extra-articular procedures) were not included. The rate of symptomatic cyclops lesions was recorded and the following parameters were evaluated: age, gender, time from injury to surgery, graft type and diameter, femoral tunnel perforation technique, fixation type, presence of knee hyperextension, preservation of the ACL remnant, associated anterolateral extra-articular procedure, associated meniscal injury and participation in sports. Results  389 patients were evaluated and 26 (6.7%) patients developed cyclops. The patients with and without cyclops lesions did not differ in age, time from injury to surgery, graft type or diameter, surgical technique, femoral fixation method, presence of knee hyperextension, remnant preservation and associated meniscal injury. The group with cyclops lesion had a higher proportion of females (10 (38.4%) vs 68 (18.7%); OR = 2.7; p  = 0.015), higher proportion of extra-articular reconstruction (18 (11.8%) vs 8 (3.4%); OR = 3.8; p  = 0.001) and higher proportion of sports practice (23 (8.6%) vs 3 (2.5%); OR = 3.6; p  = 0.026). Conclusion  In our series, 6.7% of the patients required arthroscopic removal of cyclops lesions. Female gender, associated extra-articular reconstruction and sports practice were factors related to this lesion. Remnant preservation had no relationship with cyclops lesion formation., Competing Interests: Conflito de Interesses Os autores não têm conflitos de interesses a declarar., (Sociedade Brasileira de Ortopedia e Traumatologia. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. ( https://creativecommons.org/licenses/by-nc-nd/4.0/ ).)

Objective: With the aging of the population, more patients have complained of pain due to knee Osteoarthritis (OA), and the number of arthroplasties has also increased. The objective of this study is to evaluate the prevalence of the neuropathic pain component in candidates for Total Knee Replacement and the effects of this component on their quality of life., Methods: In this cross-sectional study, patients with OA candidates for knee arthroplasty in the present institution were evaluated using the pain detection questionnaire and the Visual Analog Pain (VAS) scale to measure the pain index and the presence of associated neuropathic pain. In addition, evaluation of the quality of life and functionality using the EQ5D and SF12 questionnaires and their relationship with cases of neuropathic pain were performed., Results: One hundred twenty-six patients were evaluated, and 71.4 % were female. The age ranged from 46 to 85 years, and about 70 % of the patients had some associated clinical comorbidity. Neuropathic pain was present in 28.6 % of the patients evaluated. Patients with neuropathic pain presented worse results in the VAS evaluation, in the care, pain, and anxiety domains of the EQ5D, and in the physical and mental scores of the SF12., Conclusion: Neuropathic pain was present in 28.6 % of the patients with knee OA who are candidates for arthroplasty. Patients with associated neuropathic pain present a higher level of pain and worse quality of life scores. Recognizing this type of pathology is extremely important in fully monitoring gonarthrosis., Competing Interests: Declaration of Competing Interest The authors declare no conflicts of interest., (Copyright © 2023 HCFMUSP. Published by Elsevier España, S.L.U. All rights reserved.)

Purpose: To compare patients undergoing anterior cruciate ligament (ACL) reconstruction with hamstring grafts 7 mm or less in diameter combined with anterolateral ligament (ALL) reconstruction versus isolated ACL reconstruction with grafts greater than 7 mm in diameter., Methods: We retrospectively evaluated the descriptive data and clinical outcomes of patients who underwent primary ACL reconstruction with hamstring grafts from June 2013 to January 2020 and had a minimum follow-up period of 2 years. Patients with quadrupled or quintupled semitendinosus and gracilis autograft 7 mm or less in diameter combined with single-strand ALL reconstruction (ACL-ALL group) were matched in a 1:2 propensity ratio to patients who underwent isolated single-bundle ACL reconstruction with hamstring grafts greater than 7 mm (ACL group)., Results: We identified 30 patients in our database who met the criteria for the ACL-ALL group. The patients in this group were matched to 60 patients comprising the ACL group. Both groups were similar regarding all preoperative matched and unmatched variables. The mean ACL graft diameter was 6.8 ± 0.4 mm in the ACL-ALL group and 8.6 ± 0.6 mm in the ACL group (P < .001). The ACL-ALL group presented 1 failure (3.3%), and the ACL group presented 3 failures (5%) (P = .717). Postoperative KT-1000 measurements were similar between the groups (2.1 ± 1.1 mm vs 1.9 ± 1.2 mm, P = .114), as were postoperative pivot-shift grades (P = .652). Subjective International Knee Documentation Committee scores and Lysholm scores did not present any differences between the groups (P = .058 and P = .280, respectively)., Conclusions: Patients who undergo combined ACL-ALL reconstruction with an ACL graft diameter of 7 mm or less can achieve similar results to patients who undergo isolated ACL reconstruction with a graft diameter greater than 7 mm. An associated ALL reconstruction can be performed to increase knee stability in patients with small-diameter hamstring grafts., Level of Evidence: Level III, retrospective, comparative therapeutic trial., (Copyright © 2023 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Objectives: To report outcomes and re-dislocation rates of medial patellar stabilizers reconstruction without bone procedures for correction of anatomical risk factors for patellar instability in skeletally immature patients; to compare isolated medial patellofemoral ligament (MPFL) reconstruction to combined MPFL and medial patellotibial ligament (MPTL) reconstruction in this population., Methods: Patients with open physis and bone abnormalities including patella alta and/or increased tibial tubercle-trochlear groove (TT-TG) distance and/or trochlear dysplasia underwent MPFL reconstruction, either isolated or associated with MPTL reconstruction. Preoperative, 1-year follow-up and the latest follow-up (5 years minimum) data were collected. Radiological and clinical evaluations were conducted, with special attention to failure rate. Comparison of results from isolated MPFL and combined MPFL/MPTL reconstructions was performed., Results: Twenty-nine patients were included, 19 in the isolated MPFL group (median 14 years old; follow-up 5.8 ​± ​1.7 years) and 10 in the combined MPFL/MPTL group (median 13.5 years old; follow-up 5.2 ​± ​1.4 years). Kujala and Tegner scores increased over time, although without statistically significant differences between the two groups at the latest follow-up (p ​= ​0.840 and p ​> ​0.999, respectively). During follow-up, 5 of 19 (26.3%) isolated MPFL and 2 of 10 (20%) MPFL/MPTL reconstructions experienced recurrence of patellar dislocation (p ​> ​0.999). Trochlear dysplasia type D (p ​= ​0.028), knee rotation (p ​= ​0.009) and lateral patellar tilt angle (p ​= ​0.003) were associated with patellar instability recurrence. The isolated MPFL group showed increased laxity on physical exam at the latest follow-up compared to the 1-year follow-up (patellar glide test (p ​= ​0.002), patellar tilt test (p ​= ​0.042) and subluxation in extension (p ​= ​0.019). This increased laxity was not observed in the MPFL/MPTL group (p ​> ​0.999). Comparing both groups, the glide test was significantly better in the combined MPFL/MPTL group in comparison to the isolated MPFL reconstruction group at the latest follow-up (p ​= ​0.021)., Conclusion: MPFL reconstruction in isolation or combined with MPTL reconstruction in skeletally immature patients with additional uncorrected anatomical patellofemoral abnormalities leads to acceptable clinical outcomes within a minimum of 5 years follow-up, although has a high failure rate of 24.1%. Addition of a MPTL reconstruction to the MPFL may result in decreased patellar laxity on physical exams, as demonstrated by better patellar glide test, patellar tilt test and subluxation in extension., Level of Evidence: Level III; retrospective cohort study., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Postoperative infections after allograft implantation is a major concern in knee ligament reconstructions considering the theoretical risk of disease transmission and its potential severity. Here, we aimed to evaluate the postoperative infection rate after knee ligament reconstructions using aseptically processed allografts, and provide an overview of the allografts use in an academic tertiary hospital. A retrospective study was performed evaluating patients who underwent knee ligament reconstructions using aseptically processed allografts, including primary and revision surgeries, from 2005 to 2018. Demographic data, including the type of knee injury and trauma energy, and postoperative data were collected focusing on postoperative infections. Regarding these infected cases, further analyses were performed considering the presenting signs and symptoms, the isolated microorganism identified in culture, the time between graft implantation and diagnosis of infection (defined as acute, subacute, and late), and the need for graft removal. A total of 180 cases of ligament reconstructions were included. The mean follow-up was 8.2 (range: 2.1-15.6) years and the mean age at surgery was 34.1 (± 11.1) years. A total of 262 allografts were implanted in those 180 cases, 93 (35.5%) as bone plug allografts and 169 (64.5%) as soft tissue allografts. Common surgical indications included multiligament reconstruction (57.2%) and primary anterior cruciate ligament (ACL) reconstruction (15%). Seven cases (3.9%) presented postoperative infections. Knee pain (100%) and swelling (100%) were the most prevalent symptoms. Two cases (28.6%) presented sinus tract. Allografts were removed in two cases, the same cases that presented draining sinus ( p  = 0.04). High-energy trauma was the only statistically associated factor for infection ( p  = 0.04). No significant association between infection and the type of allograft ( p  > 0.99) or sex ( p  = 0.35) were observed. Four cases (57.1%) had monomicrobial staphylococcal infections. Based on that, the allograft-related infection rate was 1.7% (the remaining three infected cases). Nonirradiated, aseptically processed allografts have a low postoperative infection rate in knee ligament reconstructions, being a safe alternative for surgeries that require additional source, increased variety, and quantity of grafts., Competing Interests: None declared., (Thieme. All rights reserved.)

Background: Surgical wound-related traumatic complications are rarely reported in the literature. Traumatic dehiscence is unpredictable because of the trauma magnitude and the potential of associated injuries. This study aims to report the clinical outcomes and complications of a case series due to traumatic dehiscence after total knee arthroplasty (TKA) and establish possible criteria for prognosis for maintaining the implant., Methods: Patients admitted to an emergency room due to traumatic dehiscence after TKA were retrospectively evaluated. Patient data was analyzed and patients who maintained or not the arthroplasty were compared to establish prognosis factors., Results: Thirty-two patients with traumatic dehiscence after TKA were evaluated. The trauma occurred on a mean of 14.3 +/- 25.0 days after the surgical procedure, and debridement in the operating room was performed on a mean of 6.2 +/- 4.9 hours after the trauma. Twenty patients maintained the arthroplasty until the end of follow-up and did not require revision. Factors related to arthroplasty removal were associated extensor mechanism injury (p = 0.026), time from trauma to surgical debridement (p = 0.035), and infection (p = 0.0001) CONCLUSION: Traumatic dehiscence after total knee arthroplasty is an event with a high rate of complications. Extensor mechanism Injury, infection, and extended time between trauma and surgical intervention were poor prognostic factors for arthroplasty maintenance., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Purpose: To compare the failure rate in patients who underwent revision anterior cruciate ligament (ACL) reconstruction alone or associated with an extra-articular procedure. Secondary objectives were to compare ACL laxity, patient-reported outcome measures, and complication rates in these patients and, subsequently, to compare the outcomes of patients who underwent revision ACL reconstruction associated with anatomical anterolateral ligament (ALL) reconstruction or lateral extra-articular tenodesis (LET)., Methods: This was a retrospective comparative study. Patients were classified into 2 groups, according to whether (group 2) or not (group 1) an extra-articular reconstruction was performed. Patients who underwent an extra-articular procedure were further divided into ALL reconstruction (group 2A) and LET (group 2B). Baseline demographic variables, operative data and postoperative data were evaluated., Results: The groups with (86 patients) and without (88 patients) an associated extra-articular reconstruction had similar preoperative data. Group 2 had a lower failure rate (4.6% vs 14.7%; P = .038), better KT-1000, better pivot-shift, and better Lysholm. There was no difference regarding complications, except more lateral pain in group 2. Regarding the groups who underwent ALL reconstruction (41 patients) and LET (46 patients), group 2A showed better Lysholm scores. Both groups had similar failure rates and complications., Conclusions: Patients who underwent revision ACL reconstruction with a laterally based augmentation procedure had a lower failure rate than patients who underwent isolated revision ACL reconstruction. KT-1000 and pivot-shift examination were also significantly better when a lateral augmentation was performed. Complications were similar except for an increase in lateral pain in the augmented group. No clinically important differences were found when comparing the LET group to the ALL group other than a statistical improvement in the Lysholm functional scale, likely not clinically meaningful, favoring the ALL group and an increased duration of post-operative lateral pain in the LET group., Level of Evidence: III, retrospective comparative therapeutic trial., (Copyright © 2022 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Background: The purpose of this study was to compare the combined reconstruction of the superficial medial collateral ligament (sMCL) and the posterior oblique ligament (POL) with the reconstruction of the sMCL associated with the advancement of the posteromedial capsule in a complex knee injury scenario. We hypothesized that both techniques would present similar knee stability and failure rates., Methods: This is a retrospective case-control study designed to compare the results of the two reported techniques for grade III MCL instability. Patients undergoing MCL reconstruction associated with anterior cruciate ligament, posterior cruciate ligament, or both, from 2010 to 2019, were included. The following parameters were evaluated: demographic data, type of graft, time from injury to surgery, associated meniscus injuries, follow up time, mechanism of trauma, postoperative objective IKDC, subjective IKDC and Lysholm scales, range of motion, reconstruction failure and complications., Results: Seventy-eight patients were evaluated, 37 of whom underwent reconstruction of the sMCL and POL, and 41 of whom underwent reconstruction of the sMCL with advancement of posteromedial structures. There was no difference in any preoperative variable. Patients undergoing reconstruction of the sMCL + advancement had greater loss of flexion (Group 1 3.4 ± 4.6 vs Group 2 8.4 ± 7.9; P = 0.002) and more individuals with flexion loss greater than 10° (Group 1, seven patients (18.9%) vs Group 2, 17 patients (41.5%); P = 0.031). Postoperative knee stability, failures and complications were similar between groups., Conclusion: Both techniques presented good functional results and low rates of complications. However, the advancement technique showed greater flexion loss, which should be considered when choosing the best surgical option., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Purpose: To evaluate the inter-observer and inter-method reliability for patellar height measurements between conventional radiographs (CR) and magnetic resonance imaging (MRI) using one or two slices., Methods: This was a reliability study, with 60 patients divided in two groups: 30 patients with patellar instability (patella group) and 30 patients with anterior cruciate ligament or meniscus injury (control group). CR and MRI were evaluated by two independent observers. Insall-Salvati index (IS) and Caton-Deschamps index (CD) were measured using three different methods: CR, one-slice MRI or two-slice MRI. Intra-class correlation coefficients (ICC) were calculated for inter-observer reliability and inter-method reliability. Bland-Altman agreement was also calculated., Results: The inter-observer reliability was very good for the IS with ICCs of 0.93, 0.84 and 0.82, for the CR, one-slice MRI and two-slice MRI, respectively. Similarly, for the CD the ICCs were good, 0.76, 0.80 and 0.75 for the CR, one-slice MRI and two-slice MRI, respectively. No differences were found between the patella and the control group. The inter-method analysis results were: ICCs for IS (0.83, 0.86, 0.93) and CD (0.72, 0.82, 0.83), for the comparisons of CR/one-slice MR, CR/two-slice MRI and one-slice MRI/two-slice MRI, respectively. The Bland-Altman mean differences showed an 8% and a 7% increase on IS values with one-slice MRI and two-slice MRI compared to CR results, while the increase was of 9% and 1% in CD for the respective comparisons with CR., Conclusion: MRI can overestimate patellar height compared to CR, as much as an 8% increase in Insall-Salvati values when using one- or two-slice MRI measurements, and up to a 9% increase in Caton-Deschamps value when using the one-slice MRI method. It is recommended to use the CR as the preferred method when measuring patellar height., Level of Evidence: III., (© 2022. The Author(s) under exclusive licence to European Society of Sports Traumatology, Knee Surgery, Arthroscopy (ESSKA).)

Background: Alpha-defensin has been widely studied for the diagnosis of periprosthetic joint infection (PJI). However, there is a lack of detailed information regarding the proper laboratory technique of the enzyme-linked immunosorbent assay (ELISA) method, such as sample dilution., Aim: To assess the influence of dilution in the synovial fluid during ELISA for the diagnosis of knee PJI; and determine which dilution presents a better performance., Methods: Forty samples of synovial fluid from arthroplasty knees were included, 17 in the infected group and 23 in the aseptic group, according to Musculoskeletal Infection Society criteria. Initially, five synovial fluid samples from each group were assessed for quantitative analysis of alpha-defensin using ELISA. Different dilution ratios (1:10, 1:100, 1:500, 1:1000 and 1:5000) were tested based on the predetermined cutoff value of 5.2 mg/L. The dilutions that performed better were used to compare the results of all samples., Results: For infected cases, a gradual increase in the dilution of synovial fluid samples led to an equivalent increase in alpha-defensin level. The same was not observed in the aseptic cases. Both 1:1000 and 1:5000 dilutions presented satisfactory results to differentiate infected and aseptic cases. Further analyses were performed using 1:1000 and 1:5000 for all 40 samples. The 1:1000 dilution resulted in a sensitivity of 88.2% (95%CI, 66%-98%) and specificity of 95.7% (95%CI, 79%-99%), whereas the 1:5000 dilution presented a sensitivity of 94.1% (95%CI, 73%-99%) and a specificity of 100% (95%CI, 86%-100%)., Conclusion: The synovial fluid dilution had an important influence on the alpha-defensin ELISA results. Dilutions of 1:5000 showed the best performance for the diagnosis of knee PJI. The results of this study set the basis for a more reliable and reproducible alpha-defensin ELISA during the investigation of PJI, contributing to the expansion of this technique in different treatment centers worldwide., Competing Interests: Conflict-of-interest statement: All authors report no relevant conflict of interest for this article., (©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.)

Obligatory patella dislocation in flexion is an uncommon form of patellar instability, where the patella is located in extension and dislocates with every episode of knee flexion. This results in dramatically altered patellofemoral kinematics and can be extremely debilitating due to extensor strength deficits and lack of knee confidence in flexion. Concomitant pathology, which is often seen, includes a tight lateral retinaculum and a shortened extensor mechanism. Lengthening the extensor mechanism is a critical part of successful patellar stabilization, and has not been well-reported. Herein, we present a technique of quadriceps lengthening for the treatment of obligatory patellar dislocation., (© 2022 The Authors.)

The aim of this study was to evaluate the incidence of knee osteoarthritis, failure rate of reconstruction, and clinical outcomes of patients with chronic multiligament knee injuries subjected to surgical treatment. Sixty-two patients with chronic knee dislocation subjected to multiligament reconstruction between April 2008 and July 2016 were evaluated, with a minimum follow-up of 24 months. Anteroposterior and lateral radiographs were performed in the pre- and last postoperative evaluation; the progression of degenerative changes according to the Kellgren-Lawrence classification (KL) was assessed. The Schenck classification, Knee Injury and Osteoarthritis Outcome Score (KOOS), time between injury and surgery, type of postoperative rehabilitation protocol (brace vs. external fixator), and physical examination for ligament instability were also evaluated. Univariate and multivariate analysis were performed, p <0.05 was considered significant. Fifty-two (83.9%) patients were men and 16.1% ( n  = 10) were women, with a mean age of 38.8 ± 1.3 years. The time from injury to surgery was 31.1 ± 6.1 months, and the follow-up time was 6.1 ± 0.5 years. The mean final KOOS was 79.3 ± 10.4 and the overall reconstruction failure occurred in 25.8%. Of all patients, 64.5% ( n  = 40) presented a KL classification of ≥2 and were defined as having radiographic osteoarthritis (OA). As 11.7% ( n  = 7) also presented arthritis in the contralateral knee, in 53.2% ( n  = 33) the progression was most likely due to the initial injury. The failure of ligament reconstruction or residual instability was present in 15 (35.7%) of patients with OA, and only one patient (4.5%) without OA. In the multivariate analysis, only reconstruction failure was an independent predictor of OA (odds ratio = 13.2 [ p  = 0.028]). There is a high incidence of knee OA following ligament reconstruction for chronic multiligament knee injuries. Ligament reconstruction failure was the only independent predictor for the development of OA in our study., Competing Interests: None declared., (Thieme. All rights reserved.)

Objective: This article reports the range of motion, failure rate, and complications of patients with extensor mechanism injury after total knee arthroplasty (TKA) treated with extensor mechanism allograft with mid-term follow-up., Methods: Patients undergoing post-ATJ extensor mechanism transplantation from 2009 to 2018 were retrospectively evaluated. Demographics, the reason for transplantation, elapsed time from arthroplasty to transplantation, related surgical factors, immobilization time, range of motion, transplant failure, and complications were collected. The minimum follow-up was 24 months., Results: Twenty patients were evaluated. The mean follow-up was 70.8 +/- 33.6 months. The most common cause of extensor mechanism rupture was traumatic in 10 (50%) cases. Six patients underwent associated surgeries, one case of medial ligament complex reconstruction, and 5 cases of TKA revision. Eleven patients (55%) had transplant-related complications. The most common complication was an infection. Five cases presented transplant failure., Conclusion: Patients who underwent extensor mechanism allograft transplantation after total knee arthroplasty had a 25% failure rate with a mean follow-up of 6 years. Although there was no loss of flexion with the procedure and prolonged immobilization, the complication rate was not low. Level of evidence IV; case series ., Competing Interests: All authors declare no potential conflict of interest related to this article.

Purpose: There is no consensus about the mechanism and efficacy in alleviating pain of the lower-level laser therapy (LLLT) during orthodontic treatment. This study aimed to evaluate the LLLT effectiveness clinically in reducing pain caused by orthodontic movement that occurs in the early stages of treatment., Methods: The sample consisted of 54 patients in need of orthodontic treatment divided into two groups. A 28 experimental patients group (initial mean age: 26.84 years old) was undergone gallium-aluminum-arsenide infrared laser application on 12 points for each tooth immediately after the installation of the first alignment archwire, and a 26 patients control group (initial mean age: 29.13 years old) was undergone to no pain control intervention at all. Pain intensity was measured by using a visual analog scale, which was marked pain level (mm) reported in 06, 24, 48, and 72 hours. The perception of pain (beginning, peak, decline, and absence) was evaluated by filling up a questionnaire. To compare the intensity and perception of pain between groups, a nonparametric Mann-Whitney has been performed., Results: The experimental group showed levels (mm) at 6 ( p < 0.001), 24 ( p =0.004), and 48 hours ( p =0.007) and perception of pain (hours) in the peak ( p =0.026), decline ( p =0.025), and absence ( p =0.008) significantly lower compared to the group control., Conclusion: Low-level laser therapy is effective in reducing pain severity caused by orthodontic forces activation, and it promotes the analgesic action lasting effect during the most painful feeling time., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2022 Manoel Heitor Brito et al.)

To compare in magnetic resonance imaging the anatomical risk factors for anterior cruciate ligament (ACL) injury and patellar dislocation among patients who suffered acute knee injury, 105 patients with acute knee injury resulting in 38 patellar dislocations (patella group), 35 ACL injuries (ACL group), and 32 meniscus or medial collateral ligament injuries (control group) were included. These groups were compared for risk factors for patellar dislocation (patellar height, trochlear dysplasia, and quadriceps angle of action) and for ACL injury (intercondylar width, posterior inclination of tibial plateaus, and depth of the medial plateau). Univariate analysis found statistically significant differences ( p  < 0.05) between the patella and ACL groups in patellar height (Caton-Deschamps [CD] 1.23 vs. 1.07), trochlear facet asymmetry (55 vs. 68%), PTTG (13.08 vs. 8.01 mm), and the patellar tip and trochlear groove (PTTG) angle (29.5 vs. 13.71 degrees). The patella group also differed from control in medial plateau inclination (4.8 vs. 1.87 degrees), patellar height (CD 1.23 vs 1.08), trochlear facet asymmetry (55 vs. 69%), lateral trochlear inclination (17.11 vs. 20.65 degrees), trochlear depth (4.1 vs. 6.05 mm), PTTG (13.08 vs. 9.85 mm), and the PTTG angle (29.5 vs. 17.88 degrees). The ACL and control groups were similar in all measures. Multivariate analysis found the following significant determinants between the Patella and Control groups: patellar height (CD index, odds ratio [OR]: 80.13, p  = 0.015), trochlear anatomy (asymmetry of facets M/L, OR: 1.06, p  = 0.031) and quadriceps action angle (PTTG angle, OR: 1.09, p  = 0.016); between the ACL and control groups: PTTG angle (OR: 0.936, p  = 0.04) and female gender (OR: 3.876, p  = 0.032); and between the patella and ACL groups, the CD index (OR: 67.62, p  = 0.026), asymmetry of the M/L facets (OR: 1.07, p  = 0.011) and PTTG angle (OR: 1.16, p  < 0.001). In conclusion, in patients with acute knee injury, the anatomical factors patellar height, trochlear dysplasia, and quadriceps angle of action were related to the occurrence of patellar dislocation. None of the anatomical factors studied was related to the occurrence of anterior cruciate ligament injury., Competing Interests: None declared., (Thieme. All rights reserved.)

Objective  To evaluate major complications after a minimum of 5 years of follow-up after acute or recurrent patellar dislocation treated with medial patellofemoral ligament (MPFL) reconstruction with the medial third of the patellar tendon, with or without associated medialization of the tibial anterior tuberosity (TAT). Methods  A total of 50 patients were included, with a minimum follow-up of 5 years. The patients were evaluated regarding complications such as joint stiffness, recurrence of patellar dislocation, subjective instability reported by patients, and inability to return to the previous level of physical activity. Results  The mean follow-up was of 8.9 ± 2.6 years, with a minimum of 6 and maximum of 15 years; 64% of the patients were women, with a mean age of 27 ± 11.2 years old; 24% were submitted to TAT osteotomy for simultaneous medialization; and 46% were acute cases. Only 9 poor results (18%) were found, all resulting from recurrence of dislocation (12%) and complaint of subjective instability (6%) at between 36 and 60 months of follow-up. No other complications occurred. Among the poor results, five occurred in cases of acute dislocation, and four in recurrent cases, and only one had undergone TAT osteotomy. Conclusion  Reconstruction of the MPFL with the medial third of the patellar tendon, associated or not with TAT medialization osteotomy, is an alternative in the treatment of acute or chronic patellar instability, with a failure rate of only 18% in at least 5 years of follow-up. In addition, it is safe treatment, that does not present other complications., Competing Interests: Conflito de Interesses Os autores declaram não haver conflito de interesses., (Sociedade Brasileira de Ortopedia e Traumatologia. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commecial purposes, or adapted, remixed, transformed or built upon. ( https://creativecommons.org/licenses/by-nc-nd/4.0/ ).)

Background: The degree of knee hyperextension in isolation has not been studied in detail as a risk factor that could lead to increased looseness or graft failure after anterior cruciate ligament (ACL) reconstruction., Purpose: To analyze whether more than 5° of passive knee hyperextension is associated with worse functional outcomes and greater risk of graft failure after primary ACL reconstruction with hamstring tendon autograft., Study Design: Cohort study; Level of evidence, 3., Methods: A cohort of patients who had primary ACL reconstruction with hamstring tendon autografts was divided into 2 groups based on passive contralateral knee hyperextension greater than 5° (hyperextension group) and less than 5° (control group) of hyperextension. Groups were matched by age, sex, and associated meniscal tears. The following data were collected and compared between the groups: patient data (age and sex), time from injury to surgery, passive knee hyperextension, KT-1000 arthrometer laxity, pivot shift, associated meniscal injury and treatment (meniscectomy or repair), contralateral knee ligament injury, intra-articular graft size, follow-up time, occurrence of graft failure, and postoperative Lysholm knee scale and International Knee Documentation Committee subjective form scores., Results: Data from 358 patients initially included in the study were analyzed; 22 were excluded because the time from injury to surgery was greater than 24 months, and 22 were lost to follow-up. From the cohort of 314 patients, 102 had more than 5° of knee hyperextension. A control group of the same size (n = 102) was selected by matching among the other 212 patients. Significant differences in the incidence of graft failure (14.7% vs 2.9%; P = .005) and Lysholm knee scale score (86.4 ± 9.8 vs 89.6 ± 6.1; P = .018) were found between the 2 groups., Conclusion: Patients with more than 5° of contralateral knee hyperextension submitted to single-bundle ACL reconstruction with hamstring tendons have a higher failure rate than patients with less than 5° of knee hyperextension., Competing Interests: The authors have declared that there are no conflicts of interest in the authorship and publication of this contribution. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto., (© The Author(s) 2021.)

Purpose: To report the arthroscopic treatment results of a degenerative medial meniscus tear with a displaced flap into the meniscotibial recess, tibial peripheral reactive bone edema, and focal knee medial pain. As a secondary objective, we propose to identify possible factors associated with a good or poor prognosis of the surgical treatment of this lesion., Methods: From 2012 to 2018, patients who had this specific meniscus pathology and underwent arthroscopic surgical treatment were retrospectively evaluated. Patients with Kellgren-Lawrence (KL) classification greater than 2 were excluded. KL classification, the presence of an Outerbridge grade III/V chondral lesion of the medial compartment, limb alignment, body mass index, and smoking were evaluated. The subjective outcomes included the International Knee Documentation Committee score, improvement in the pain reported by patients, and the Global Perceived Effect (GPE) scale score., Results: A total of 69 patients were evaluated. The mean age was 58.6 ± 7.1 years. The follow-up time was 48.7 ± 20.8 months. Fifty-five (79.7%) patients reported pain improvement. The postoperative International Knee Documentation Committee was 62.6 ± 15.4, and the mean GPE was 2.3 ± 2.6. Fourteen patients (20.3%) showed no improvement in pain, and 7 patients (10.2%) presented complications. Groups that improved (GPE > 0) and did not improve (GPE < 0) did not present differences regarding age, sex, follow-up time, chondral lesions, or body mass index. Patients without improvement had a greater incidence of smoking (P = .001), varus alignment (P = .008), and more advanced KL classification (P < .001). In the multivariate analysis based on the GPE score, KL classification (P = .038) and smoking (P = .003) were significant., Conclusions: Arthroscopic surgical treatment of degenerative medial meniscal tears with a meniscal flap displaced into the meniscotibial recess and adjacent focal bone edema in the tibia shows good results in approximately 80% of cases. Smoking and KL grade 2 were factors associated with poor prognosis of surgical treatment., Level of Evidence: Level IV (case series)., (Copyright © 2021 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Objective: To analyse the distances between the femoral insertions of the popliteus tendon (PT) and the lateral collateral ligament (LCL) through dissections of cadaveric specimens in a mixed population., Methods: Fresh cadavers were dissected, and the anthropometric data of all specimens were recorded. The distances from the origin of the PT to the LCL in the femoral region and the diameter of each structure were measured using a digital calliper., Results: In total, 11 unpaired knees were dissected, eight men and three women, with an average age of 71.5 ± 15.2 years, weight of 57.2 ± 15.6 kg, and a mean height of 170.5 ± 8.2 cm. The distance from the center of the femoral footprint of the LCL to the PT was 10.0 ± 2.4 mm. The distances between the edges closest to each other and those more distant from each other were 3.1 ± 1.1 mm and 16.3 ± 2.4 mm, respectively., Conclusion: The distance between the midpoints of the PT and the LCL in our mixed population is smaller than the distances often reported in the literature. PLC reconstruction with separate tunnels for the LCL and PT may not be technically possible for individuals of any population. Level of Evidence III, Diagnostic studies. , Competing Interests: All authors declare no potential conflict of interest related to this article.

Background: The quantitative alpha-defensin enzyme-linked immunosorbent assay (ELISA) demands a prior synovial fluid centrifugation, whereas this processing is not routinely required prior to the alpha-defensin lateral flow test., Aim: To evaluate whether a prior synovial fluid centrifugation could lead the lateral flow performance to achieve comparable results to ELISA during periprosthetic joint infection (PJI) diagnosis., Methods: Fifty-three cases were included in this study: 22 classified as PJI and 31 classified as aseptic cases, according to Musculoskeletal Infection Society 2013 criteria. Synovial fluid samples were submitted to centrifugation, and the supernatant was evaluated by ELISA and lateral flow tests. The sensitivity (SE), specificity (SP) and accuracy of each method were calculated as well as the agreement between those two methods., Results: In all of the 31 samples from aseptic patients, alpha-defensin ELISA and lateral flow tests showed negative results for infection. Regarding the 22 infected patients, the lateral flow test was positive in 19 cases (86.4%) and the ELISA was positive in 21 (95.5%). Sensibility, SP and accuracy were, respectively, 86.4% (95%CI: 65.1%-97.1%), 100% (95%CI: 88.8%-100%) and 93.2% (95%CI: 82.8%-98.3%) for the lateral flow test and 95.5% (95%CI: 77.2%-99.9%), 100% (95%CI: 88.8%-100%) and 98.1% (95%CI: 89.9%-100%) for ELISA. An agreement of 96.2% between those methods were observed. No statistical difference was found between them ( P = 0.48)., Conclusion: Alpha-defensin lateral flow test showed high SE, SP and accuracy after a prior synovial fluid centrifugation, achieving comparable results to ELISA. Considering the lower complexity of the lateral flow and its equivalent performance obtained in this condition, a prior centrifugation might be added as a valuable step to enhance the PJI diagnosis., Competing Interests: Conflict-of-interest statement: The authors declare that there are no any conflicts of interest., (©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.)

Congenital femoral deficiency (CFD) is a rare disorder with several limb anomalies including limb shortening and knee cruciate ligament dysplasia.Limb lengthening is usually performed to correct lower limb discrepancy. However, complications, such as knee subluxation/dislocation, can occur during this treatment.Here, we explore CFD knee abnormalities and knee dislocation during limb elongation, discussing when and whether knee ligament reconstruction prior to the lengthening would be necessary to reduce the risk of knee dislocation.There is not enough support in the literature for the routine reconstruction of cruciate ligaments in CFD patients.Of note, in cases of severe anteroposterior or posterolateral rotatory instability, cruciate ligament reconstruction might be considered to decrease the risk of knee subluxation/dislocation during the lengthening treatment. Cite this article: EFORT Open Rev 2021;6:565-571. DOI: 10.1302/2058-5241.6.200075., Competing Interests: ICMJE Conflict of interest statement: The author declares no conflict of interest relevant to this work., (© 2021 The author(s).)

Purpose: To compare the functional outcomes, knee stability, failure rate and complication rates of combined anterior cruciate ligament (ACL) and anterolateral ligament (ALL) reconstruction with hamstrings grafts between acute and chronic cases., Methods: Consecutive patients who underwent combined ACL and ALL reconstruction with hamstrings grafts were evaluated. Patients operated on less than 8 weeks after injury were allocated to group 1, and the others were allocated to group 2. Demographic data, knee stability, and functional outcomes of the 2 groups were evaluated., Results: Thirty-four patients in the acute group and 96 in the chronic group were evaluated. The follow-up time was similar between the groups (28.7 ± 5.2 [24-43] months vs 29.4 ± 7.2 [24-58] months; P = 0.696). No differences were found between the groups in age, sex, trauma mechanism, presence of knee hyperextension, graft diameter, and meniscal injuries. There was no difference between the groups in the postoperative KT-1000 and in the pre- or postoperative pivot shift. The preoperative KT-1000 was higher in group 2 (7.9 ± 1.1 vs 7.4 ± 1.2; P = 0.031). There were no differences in the International Knee Documentation Committee or Lysholm. Three (2.3%) patients developed failure, 1 (2.9%) in group 1 and 2 (2.1%) in group 2. The total complication rate was 10% and did not differ between the groups., Conclusions: Combined ACL and ALL reconstruction has similar outcomes in patients undergoing surgery in the acute and chronic phases. Patients with chronic injury have similar knee stability, functional scores, and failure rates as acute-injury patients, and patients with acute injury have no more complications than chronic patients., Level of Evidence: Level III, retrospective comparative therapeutic trial., (Copyright © 2021 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Objective: The synovial fold is an intra-articular structure found in more than 50% of the knees, which can cause symptoms similar to meniscal injuries. These symptoms are mostly related to hypertrophy of the synovial fold resulting from inadequate physical activity. Conservative treatment with readjustment of sports activity and muscle rebalancing solves most cases. Rare cases require surgical treatment, which is indicated due to the persistence of instability, blockage and pain. We present our experience in the treatment of this pathology., Methods: 58 patients (70 knees), with 62 knees treated conservatively and 8 treated surgically exclusively for the pathological synovial fold. Results: Description of the series and treatment results are reported., Conclusion: The non-surgical treatment of the pathological synovial fold of the knee provided good results within 60 days of rehabilitation program in almost 90% of the patients. Arthroscopic resection of the synovial fold is a surgery that has a longer and laborious rehabilitation period, despite good results in most cases. Level of Evidence IV, Case series ., Competing Interests: All authors declare no potential conflict of interest related to this article.

Background: Tibial tubercle osteotomy with concomitant distalization for the treatment of patellar instability remains controversial, as it may cause anterior knee pain and chondral degeneration., Purpose: To evaluate radiographic, clinical, and functional outcomes in patients who had patellar instability with patella alta and underwent tibial tubercle osteotomy with distalization (TTO-d) as well as medial patellofemoral ligament reconstruction., Study Design: Case series; Level of evidence, 4., Methods: Included in this study were 25 patients (31 cases) (mean age at surgery, 28.7 years; range, 14-33 years) with patellar instability and patella alta who underwent TTO-d with minimum 1-year follow-up. The Caton-Deschamps index (CDI), tibial tubercle-trochlear groove (TT-TG) distance, and amount of distalization were assessed. Clinical and functional variables included J-sign, anterior knee pain, apprehension test, Tegner activity level, and Kujala score., Results: The mean follow-up period was 2.62 years. The mean TT-TG was 16.15 mm (range, 7-24 mm); the mean CDI changed from 1.37 (1.25-1.7) preoperatively to 1.02 (0.9-1.12) postoperatively ( P = .001); and the mean amount of tibial tubercle distalization was 8.80 mm (range, 4-16 mm). Lateral release (22 cases; 71.0%), medialization of tibial tubercle (17 cases; 54.8%), and autologous chondrocyte implantation (4 cases; 12.9%) were other associated procedures. The J-sign improved in 30 cases (96.8%; P = .001), and there was a complete resolution of anterior knee pain in 22 cases (71.0%; P = .001). An exploratory analysis showed that patellar cartilage defect severity was correlated with persistent pain ( P = .005). The apprehension test became negative in all cases ( P = .001). The median Kujala score increased from 52 to 77 ( P = .001), and the median Tegner activity level improved from 3 to 4 ( P = .001). No cases of osteotomy nonunion were reported. One case (3.2%) of patellar instability recurrence and 3 cases (6.5%) with painful hardware were observed., Conclusion: TTO-d resulted in good radiographic, clinical, and functional outcomes providing proper patellar stability to patients with patella alta. TTO-d appears to be a safe and efficient procedure with low complication rates, providing an additional tool for the personalized treatment of patellar instability., Competing Interests: The authors declared that there are no conflicts of interest in the authorship and publication of this contribution. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto., (© The Author(s) 2021.)

The objective of this study is to report the functional outcomes, complications, and reconstruction failure rate of patients undergoing posterolateral complex reconstruction with a single femoral tunnel technique. Patients with posterolateral complex injuries associated with injury of the anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), or both undergoing surgical treatment with the single femoral tunnel technique were included in the study. The International Knee Documentation Committee (IKDC) and Lysholm's scales were evaluated, in addition to age, gender, time between trauma and surgery, trauma type, range of motion (ROM) restrictions, peroneal nerve injury, and reconstruction failure. Sixty-six patients were included. Eighteen underwent ACL and posterolateral complex (PLC) reconstruction (group 1), 24 underwent ACL, PCL, and PLC reconstruction (group 2), and 24 underwent PCL and PLC reconstruction (group 3). The mean follow-up was 63 months. The subjective IKDC was 83.7 ± 14.6 for group 1, 74.3 ± 12.6 for group 2, and 66.3 ± 16.0 for group 3 ( p  < 0.001). The Lysholm's score was 87.1 ± 12.8 for group 1, 79.5 ± 15.0 for group 2, and 77.7 ± 15.2 for group 3 ( p  = 0.042). There were six reconstruction failures among the patients (9.1%) with no differences among the groups ( p  = 0.368). Female gender and reconstruction failure were associated with worse outcomes. Patients undergoing reconstruction of PLC structures with the single femoral tunnel technique achieved good functional outcomes and a failure rate similar to literature. Patients undergoing only combined ACL reconstruction showed better outcomes than patients undergoing combined PCL reconstruction. Female gender was associated with a worse functional outcome irrespective of the injury type., Competing Interests: None declared., (Thieme. All rights reserved.)

Background: Isolated reconstruction of the anterior cruciate ligament (ACL) does not reestablish the normal knee biomechanics in cases of associated injuries to the anterolateral structures. Studies evaluating the potential clinical effect of anterolateral ligament (ALL) injury on the treatment of ACL injuries are necessary to validate the findings of biomechanical studies., Purpose: To evaluate the clinical outcomes and failure rate of ACL reconstruction in patients with and without ALL injury diagnosed using magnetic resonance imaging., Study Design: Cohort study; Level of evidence, 2., Methods: A prospective cohort of patients with acute ACL injury was divided into 2 groups based on the presence (ALL group) or absence (no-ALL group) of ALL injury on preoperative magnetic resonance imaging scans. Both groups underwent anatomic reconstruction of the ACL with autologous hamstring tendon grafts. The Lysholm and subjective IKDC scores (International Knee Documentation Committee), KT-1000 arthrometer and pivot-shift test results, reconstruction failure rate, incidence of contralateral ACL injury, presence of associated meniscal injury, and presence of knee hyperextension were evaluated., Results: A total of 182 patients were evaluated. Postoperative mean ± SD follow-up was 33.6 ± 7.1 and 36.1 ± 8.1 months for the ALL and no-ALL groups, respectively. No significant differences were found between the groups in terms of age, sex, knee hyperextension, duration of injury before reconstruction, follow-up time, or associated meniscal injuries. In the preoperative evaluation, the pivot-shift grade was similar, and the ALL group had worse KT-1000 arthrometer values (7.9 ± 1.2 mm vs 7.2 ± 1.1 mm; P < .001). In the postoperative evaluation, patients in the no-ALL group had a lower reconstruction failure rate (10.2% vs 1.4%; P = .029) and better clinical outcomes according to the IKDC subjective (85.5 ± 10.7 vs 89.1 ± 6.6; P = .035) and Lysholm scores (85.9 ± 10.1 vs 92.0 ± 6.3; P < .001). There was no postoperative difference in the KT-1000 or pivot-shift results., Conclusion: Combined ACL and ALL injuries were associated with significantly less favorable outcomes than were isolated ACL injuries at a minimum follow-up of 2 years after ACL reconstruction. Patients with concomitant ALL injury showed a higher rerupture rate and worse functional scores.

Background: Evaluate the effect of bacteria drug resistance profile on the success rates of debridement, antibiotics and implant retention., Methods: All early acute periprosthetic infections in hip and knee arthroplasties treated with DAIR at our institution over the period from 2011 to 2015 were retrospectively analyzed. The success rate was evaluated according to the type of organism identified in culture: multidrug-sensitive (MSB), methicillin-resistant Staphylococcus aureus (MRSA), multidrug-resistant Gram-negative bacteria (MRB) and according to other risk factors for treatment failure. The data were analyzed using univariate and multivariate statistics., Results: Fifty-seven patients were analyzed; there were 37 in the multidrug-sensitive bacteria (MSB) group, 11 in the methicillin-resistant Staphylococcus aureus (MRSA) group and 9 in the other multidrug-resistant Gram-negative bacteria (MRB) group. There was a statistically significant difference (p < 0.05) in the treatment failure rate among the three groups: 8.3% for the MSB group, 18.2% for the MRSA group and 55.6% for the MRB group (p = 0.005). Among the other risk factors for treatment failure, the presence of inflammatory arthritis presented a failure rate of 45.1 (p < 0.05)., Conclusion: DAIR showed a good success rate in cases of early acute infection by multidrug-sensitive bacteria. In the presence of infection by multidrug-resistant bacteria or association with rheumatic diseases the treatment failure rate was higher and other surgical options should be considered in this specific population. The MRSA group showed intermediate results between MSB and MRB and should be carefully evaluated.

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.

Improved understanding and treatment of posterior medial and lateral meniscus root tears have attracted increasing interest. These lesions significantly compromise meniscal function, which can result in an outcome resembling total meniscectomy, and are also a potential cause of knee instability. Despite facilitating repair procedures and reducing the operative time for these lesions, all-inside meniscal repair devices are not available in all circumstances or registered for use in all countries worldwide. Furthermore, all-inside arthroscopic devices can be expensive. Therefore, low-cost alternatives for the treatment of these lesions must be identified. We present 2 efficient and safe techniques: an outside-in technique for repairing medial meniscus root tears and a technique using a simple needle inserted through the transtibial tunnel for lateral meniscal root repairs, neither of which requires the use of specific instruments, thus enabling appropriate treatment of posterior medial and lateral meniscus root tears., (© 2020 by the Arthroscopy Association of North America. Published by Elsevier.)

Objective: To describe the first series of cases of autologous chondrocyte implantation (ACI) in collagen membrane performed in Brazil., Methods: ACI was performed in 12 knees of 11 patients, aged 32.1 ± 10.9 years, with 5.3 ± 2.6 cm 2 full-thickness knee cartilage lesions, with a six-month minimum follow-up. Two surgical procedures were performed: arthroscopic cartilage biopsy for isolation and expansion of chondrocytes, which were seeded onto collagen membrane and implanted in the lesion site; the characterization of cultured cells and implant was performed using immunofluorescence for type II collagen (COL2) for cell viability and electron microscopy of the implant. Clinical safety, KOOS and IKDC scores and magnetic resonance imaging were evaluated. We used repeated-measures ANOVA and post-hoc comparisons at α = 5%., Results: COL2 was identified in the cellular cytoplasm, cell viability was higher than 95% and adequate distribution and cell adhesion were found in the membrane. The median follow-up was 10.9 months (7 to 19). We had two cases of arthrofibrosis, one of graft hypertrophy and one of superficial infection as complications, but none compromising clinical improvement. KOOS and IKDC ranged from 71.2 ± 11.44 and 50.72 ± 14.10, in preoperative period, to 85.0 ± 4.4 and 70.5 ± 8.0, at 6 months (p = 0.007 and 0.005). MRI showed regenerated tissue compatible with hyaline cartilage., Conclusion: ACI in collagen membrane was feasible and safe in a short-term follow-up, presenting regenerated formation visualized by magnetic resonance imaging and improved clinical function. Level of evidence IV, Case series ., Competing Interests: Authors declare as conflict of interest that MKD is a medical education consultant for Geistlich Pharma of Brazil.

Objective: To evaluate the profile of blood loss and blood transfusions after the introduction of Tranexamic acid (TXA) in a tertiary university hospital in Brazil., Methods: 173 patients were retrospectively divided into two groups: the ones who received TXA and the control group. Hemoglobin levels (Hb), drain output, transfusion rates, and thromboembolic events were measured., Results: Among the patients included in this study, 82 cases received TXA. Blood transfusion occurred in 3 cases of the TXA group (3.7%), and in 27 control group cases (29.7%; p < 0.001). The average Hb decrease was 2.7 g/dl (± 1.39) and the median drain output was 270 mL in the TXA group. In the control group, the values were 3.41 g/dl (± 1.34; p < 0.001) and 460 mL (p < 0.001), respectively. Thromboembolic events occurred in 2 TXA group cases (2.4%) and in 3 control group cases (3.3%; p > 0.999)., Conclusion: TXA was effective in reducing blood transfusion rates, Hb decrease, and drain output on the 1st postoperative day without increasing thromboembolic events. Level of evidence III, Retrospective comparative study., Competing Interests: All authors declare no potential conflict of interest related to this article.

Background: The anatomy and function of the quadriceps muscle play a role in patellofemoral stability. Few studies have evaluated anatomic differences in the vastus medialis between patients with and without patellar instability., Purpose: To compare the anatomy of the vastus medialis using magnetic resonance imaging in patients with patellar instability to a control group., Study Design: Cross-sectional study; Level of evidence, 3., Methods: A group of patients with patellar instability were sex-matched with a control group with anterior cruciate ligament tears, meniscal injuries, or sprains; patients younger than 15 years were excluded. The anatomy of the vastus medialis was examined by the distance between the distal origin of the vastus medialis in the femur and the medial femoral condyle, the distance from the proximal pole of the patella to the most distal insertion of the muscle and its ratio to the length of the articular surface of the patella, and a qualitative description of the insertion position of the muscle fibers (directly in the patella or the medial retinaculum)., Results: Both groups comprised 78 knees (48 female; 61.5%). The mean age in the control and patellar instability groups was 30.2 ± 7.8 years and 25.6 ± 7.5 years, respectively ( P = .001). The distance from the vastus origin to the condyle was 27.52 ± 3.49 mm and 26.59 ± 3.43 mm, respectively ( P = .041); the distance from the proximal pole of the patella to the most distal muscle insertion was 17.59 ± 5.54 mm and 15.02 ± 4.18 mm, respectively ( P < .001); and the ratio of this distance to the joint surface was 0.586 ± 0.180 and 0.481 ± 0.130, respectively ( P < .001). In 75.6% of knees in the patellar instability group, the insertion of the vastus was into the medial retinaculum and not into the patella compared with 52.6% in the control group ( P = .003; odds ratio, 2.8)., Conclusion: The distal insertion of the vastus medialis differed in knees with patellar instability, with a more proximal insertion and less patellar coverage relative to controls, and was more frequently found in the retinaculum instead of directly in the patella., Competing Interests: The authors declared that there are no conflicts of interest in the authorship and publication of this contribution. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto., (© The Author(s) 2019.)

Objective: To retrospectively evaluate the results after applying a protocol for treating acute infections in cases of total knee arthroplasty and to establish factors predictive of success or failure., Methods: Thirty-two patients who were diagnosed with acute infection of the knee following total arthroplasty between 2004 and 2009 were retrospectively evaluated. Infections following arthroplasty were treated in accordance with the protocol for acute infections following arthroscopy recommended at our institution., Results: With application of a treatment protocol for acute infections following total knee arthroplasty, 26 patients (81.2%) had good results and 6 (18.8%) had unsatisfactory results. Statistical analysis showed that the variables correlated with a worse prognosis were age (p = 0.038) and number of surgical debridement procedures performed (p = 0.038)., Conclusion: Our treatment routine was effective for infection. Prosthesis revision was performed in 2 cases when the initial surgical debridement failed to control the infection. Nível de Evidência IV, Série de casos. , Competing Interests: All authors declare no potential conflict of interest related to this article.

Purpose: The purpose of this article is to review anatomical, biomechanical, and clinical data of the medial patellotibial ligament (MPTL) and medial patellomeniscal ligament (MPML), as well as studies focusing on the medial patellofemoral ligament (MPFL) but with relevant data about the MPTL and MPML., Methods: A literature search of articles specifically addressing the MPTL and/or MPML was included along with studies focusing on the MPFL but with relevant data about the MPTL and MPML., Results: The medial patellar ligaments responsible for maintaining the stability of the patellofemoral (PF) joint include the MPFL, the MPTL, and the MPML. The MPFL is considered the primary restraint to lateral patellar translation, while the latter two are considered secondary restraints. There is robust literature on the anatomical, imaging, and biomechanical characteristics of the MPFL, and also the clinical outcome of its injury and surgical reconstruction; much less is known about the MPTL and MPML. Isolated MPFL reconstruction has good clinical and functional outcomes, with a low failure rate when defined as frank re-dislocation. Complications, including continued episodes of patellar apprehension and subluxation, remain present in most series. In addition, the current literature primarily includes a homogeneous population with few excessive anatomic dysplastic factors. There is lack of knowledge on the role of MPTL and MPML in (potentially) aiding patella stabilization and improving clinical outcomes. Understanding the role of the medial-sided patellar ligaments, in particular the role of the secondary stabilizers, in PF function and injury will aid in this goal., Conclusion: MPTL and MPML have consistent basic science literature, as well as favorable clinical outcomes of surgical patellar stabilization with reconstruction of the MPTL. However, there is much heterogeneity among clinical case series and lack of comparative studies to allow clear indication for the role of isolated or combined surgical reconstruction in patellar stabilization. Therefore, this comprehensive review helps understand the current knowledge and the possible applications in the orthopedic clinical practice., Level of Evidence: V.

Objective: To present the indications, technical aspects, and initial results of the first cases using Endo-Model™ implants in Brazil., Methods: A prospective study was conducted. It included nine patients submitted to a total knee arthroplasty, of which six were primary and three were revisions, using exclusively the Endo-Model™ implant. These patients were followed for an average of 12 months and evaluated with functional scores, such as the Knee injury and Osteoarthritis Outcome Score (KOOS), Knee Society Score (KSS), and visual analog pain scale (VAS)., Results: There were statistically significant improvements in all scores evaluated in every patient. Only one complication occurred postoperatively (apraxia of the peroneal nerve) and did not require surgery revision., Conclusion: The use of a rotating-hinge implant for knee arthroplasty is a new option for complex cases with severe instability in Brazil; the initial results are satisfactory.

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.

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.

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., (Copyright © 2017 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Objective: Translation, cultural adaptation, and validation of the new version of the Knee Society Score - The 2011 KS Score - into Brazilian Portuguese and verification of its measurement properties, reproducibility, and validity. In 2012, the new version of the Knee Society Score was developed and validated. This scale comprises four separate subscales: (a) objective knee score (seven items: 100 points); (b) patient satisfaction score (five items: 40 points); (c) patient expectations score (three items: 15 points); and (d) functional activity score (19 items: 100 points)., Method: A total of 90 patients aged 55-85 years were evaluated in a clinical cross-sectional study. The pre-operative translated version was applied to patients with TKA referral, and the post-operative translated version was applied to patients who underwent TKA. Each patient answered the same questionnaire twice and was evaluated by two experts in orthopedic knee surgery. Evaluations were performed pre-operatively and three, six, or 12 months post-operatively. The reliability of the questionnaire was evaluated using the intraclass correlation coefficient (ICC) between the two applications. Internal consistency was evaluated using Cronbach's alpha., Results: The ICC found no difference between the means of the pre-operative, three-month, and six-month post-operative evaluations between sub-scale items., Conclusion: The Brazilian Portuguese version of The 2011 KS Score is a valid and reliable instrument for objective and subjective evaluation of the functionality of Brazilian patients who undergo TKA and revision TKA.

Background: Patellar instability is a debilitating disease. An important factor related to recurrent dislocation is patellar height. A new method of patellar height measurement, the plateau-patella angle (PPA), was proposed in 2011. However, to date, there is no study evaluating the use of this method in patients with patellar instability. The aim of this study was to evaluate the PPA in patients with recurrent patellar dislocation., Methods: This was a retrospective evaluation of the radiographs of 78 knees with patellar instability. Patellar height was measured using the Insall-Salvati (I/S), Caton-Deschamps (C/D) and Blackburne-Peel (B/P) indices and the PPA. The qualitative and quantitative correlations between the various methods and between observers were calculated., Results: The PPA had a Pearson correlation of 0.76 (P<0.001) with the I/S index, 0.78 (P<0.001) with the C/D index and 0.90 (P<0.001) with the B/P index. In the qualitative correlation using the Spearman coefficient, the PPA had a correlation of 0.52 (P<0.001) with the I/S index, 0.72 (P<0.001) with the C/D index and 0.70 (P<0.001) with the B/P index. The correlations between the conventional methods were as follows: 0.57 (P<0.001) between the I/S and C/D indices; 0.61 (P<0.001) between the I/S and B/P indices; and 0.73 (P<0.001) between the C/D and B/P indices., Conclusion: The determination of the PPA is a reproducible method that is consistent with the methods currently used to measure patellar height in patients with recurrent patellar dislocation., (Copyright © 2017 Elsevier B.V. All rights reserved.)