Routine Knee Research Articles

Incidence of Encountering the Infrapatellar Nerve Branch of the Saphenous Nerve During a Midline Approach for Total Knee Arthroplasty.

Background:The infrapatellar nerve branch (IPNB) of the saphenous nerve supplies cutaneous sensation to the anterolateral knee. Given its location and variable course, the IPNB is suspected to be at risk of injury with commonly used incisions around the knee. Nerve injury may lead to painful neuroma formation. To our knowledge, no study has evaluated the incidence at which the IPNB is encountered during the anterior approach incision for a routine total knee arthroplasty (TKA). The purpose of this study was to see whether the general joint arthroplasty surgeon can identify and examine the location of the IPNB encountered during primary TKA and to determine whether these branches would be transected during a standard medial arthrotomy.Methods:Seventy-three patients (76 knees) underwent primary TKA using a standard midline approach with a medial parapatellar arthrotomy. The IPNB was identified, and the distance was measured from the inferior pole of the patella to the point where the nerve crossed the medial border of the patellar tendon. This distance was then compared with the length of the arthrotomy in the same knee to determine whether the nerve would be transected.Results:The IPNB was encountered in all knees with a mean distance of 2.82 cm (95% confidence interval, 2.58–3.06) distal to the inferior pole of the patella during the arthrotomy. Patient characteristics including sex, height, and body mass index were not markedly associated with nerve location.Conclusion:The IPNB of the saphenous nerve is at risk for injury and routinely encountered by the general orthopaedic surgeon during a standard TKA medial parapatellar approach without the aid of magnification or dye.

Combining ACL Oblique Coronal MRI with the Routine Knee MRI Protocol in the Diagnosis of ACL Bundle Lesions. Can It Add A Value?

Abstract Background: The Anterior Cruciate Ligament (ACL) is formed of two bundles. Routine MRI protocol is usually insufficient to delineate both bundles structure, so diagnosis of AM and PL bundle injury is often limited, and development of further imaging orientation and pulse sequences is key for further improving characterization of these bundles. Accurately grading the ACL tears and differentiating between complete and partial tears as well as assessing the two bundles is key in improving the clinical and surgical management. Aim of Study: The purpose of this study is to evaluate the diagnostic value of combining oblique coronal images to the routine MRI protocol for better assessment of the ACL bundles, thus improving management outcome by performing two MRI protocols and comparing them to the arthroscopic findings. Patients and Methods: This prospective study was con-ducted between January 2016 and February 2018 in Ain Shams University Hospitals and private centers. The study population has consisted of 32 patients (26 men & 6 women), ranging between 19-45 years, with mean age of 27.11 years. All patients were suspected of ACL injury referred from the outpatient clinic of orthopedic. All patients were examined by MRI examinations com-posed of sagittal T2-weighted Fast-Spin Echo (FSE), coronal T2-weighted FSE, and axial T2-weighted. The sagittal images were planned on axial localizer by 15-degree medial angling on perpendicular line to the bicondylar line and by oblique coronal MRI were the oblique coronal STIR images named were planned on midsagittal localizer in the plane parallel to the ACL and the roof of the intercondylar notch (Blumensaat's line). A consultant orthopedic surgeon did a diagnostic arthros-copy for all included patients using standard parapatellar portals visualizing the ACL with direct visualizing of both bundles and accordingly classifying each bundle as torn or intact. Results: The Oblique coronal MRI showed a better agree-ment with the diagnostic arthroscopy than routine MRI [weight-ed Kappa; k=0.865 & 0.753 respectively]. For diagnosis of Anteromedial Bundle (AMB) tear the sensitivity was 90.9%, specificity 80%, with overall accuracy of 87.5%. For diagnosis of Posterolateral Bundle (PLB) tear. The sensitivity was 95.5%, specificity 90%, with overall accuracy of 93.8%. Conclusion: The adding of oblique coronal imaging to routine MRI protocol revealed better delineation of the ACL bundles, increasing the accuracy of diagnosis each or both bundle lesions, providing significant benefit in further man-agement and outcome in patient with suspected ACL injury.

Interpreter proxy versus healthcare interpreter for administration of patient surveys following arthroplasty: a pilot study

BackgroundClinical quality registries and other systems that conduct routine post-discharge surveillance of patient outcomes following surgery may have difficulty surveying patients who have limited proficiency in the language of the healthcare provider. Interpreter proxies (family and carers) are often used due to limited access to certified healthcare interpreters (due to cost or availability). The aim of this study was to assess the reliability of engaging interpreter proxies compared with certified healthcare interpreters for the administration of patient-reported health-related surveys for people with limited English proficiency (LEP).MethodsPeople with LEP and due for a routine 6-month telephone follow-up post knee or hip arthroplasty were invited to participate. Participants were randomly allocated to having their first interview with an interpreter proxy or a certified healthcare interpreter followed by the second (crossover) interview within 2 weeks (range: 4 to 12 days) after the first interview using the alternative method. Agreement between the two methods was assessed using quadratic weighted Cohen’s kappa, intraclass correlation and concordance correlation co-efficient where appropriate for EQ-5D health domains, total Oxford hip and knee scores, patient satisfaction, operation success, readmission, reoperation, and post-surgical complication responses. The mean of the differences between the same data items collected by each of the two methods was also calculated.ResultsEighty five participants (96%) completed the study. There was substantial to excellent inter-rater agreement (kappa = 0.69–0.87 and ICCs above 0.74) for all but one measure. The mean differences between family proxy and healthcare interpreter scores for each participant were small, ranging from 0.01 (score range of 1–5) to 0.72 (score range of 0–100).ConclusionThese results suggest that using interpreter proxies is a reliable alternative to certified healthcare interpreters in conducting patient-reported health surveys, potentially making this process easier and cost effective for researchers and registries.

Image Artifact Management for Clinical Magnetic Resonance Imaging on a 7 T Scanner Using Single-Channel Radiofrequency Transmit Mode.

The aim of this work was to devise mitigation strategies for addressing a range of image artifacts on a clinical 7 T magnetic resonance imaging scanner using the regulatory-approved single-channel radiofrequency transmit mode and vendor-supplied radiofrequency coils to facilitate clinical scanning within reasonable scan times. Optimized imaging sequence protocols were developed for routine musculoskeletal knee and neurological imaging. Sources of severe image nonuniformities were identified, and mitigation strategies were devised. A range of custom-made high permittivity dielectric pads were used to compensate for B1 and B1 inhomogeneities, and also for magnetic susceptibility-induced signal dropouts particularly in the basal regions of the temporal lobes and in the cerebellum. Significant improvements in image uniformity were obtained using dielectric pads in the knee and brain. A combination of small voxels, reduced field of view B0 shimming, and high in-plane parallel imaging factors helped to minimize signal loss in areas of high susceptibility-induced field distortions. The high inherent signal-to-noise ratio at 7 T allowed for high receiver bandwidths and thin slices to minimize chemical shift artifacts. Intermittent artifacts due to radiofrequency inversion pulse limitations (power, bandwidth) were minimized with dielectric pads. A patient with 2 implanted metallic cranial fixation devices located within the radiofrequency transmit field was successfully imaged, with minimal image geometric distortions. Challenges relating to severe image artifacts at 7 T using single-channel radiofrequency transmit functionality in the knee and brain were overcome using the approaches described in this article. The resultant high diagnostic image quality paves the way for incorporation of this technology into the routine clinical workflow. Further developmental efforts are required to expand the range of applications to other anatomical areas, and to expand the evidence- and knowledge-base relating to the safety of scanning patients with implanted metallic devices.

Prediction of Autograft Hamstring Size for Anterior Cruciate Ligament Reconstruction Using MRI.

Hamstring autografts with a diameter of less than 8 mm for ACL reconstruction have an increased risk of failure, but there is no consensus regarding the best method to predict autograft size in ACL reconstruction. (1) What is the relationship between hamstring cross-section on preoperative MRI and intraoperative autograft size? (2) What is the minimum hamstring tendon cross-sectional area on MRI needed to produce an autograft of at least 8 mm at its thickest point? This was a retrospective cohort study of 68 patients. We collectively reviewed patients who underwent ACL reconstruction by three separate fellowship-trained surgeons at the Carilion Clinic between April 2010 and July 2013. We searched the patient records database of each surgeon using the keyword "ACL". A total of 293 ACL reconstructions were performed during that time period. Of those, 23% (68 patients) had their preoperative MRI (1.5 T or 3 T magnet) performed at the Carilion Clinic with MRI confirmation of acute total ACL rupture. Exclusion criteria included previous ACL reconstructions, multiligamentous injuries, and history of acute hamstring injuries.After applying the exclusion criteria, there were 29 patients in the 1.5 T magnet group and 39 in the 3 T group. Median age (range) was 29 years (12 to 50) for the 1.5 T group and 19 years (9 to 43) for the 3 T group. The patients were 41% female in the 1.5 T group and 23% female in the 3 T group. Use of 1.5 T or 3 T magnets was based on clinical availability and scheduling. The graft's preoperative cross-sectional area was compared with the intraoperative graft's diameter. The MRI measurements were performed by a single musculoskeletal radiologist at the widest point of the medial femoral condyle and at the joint line. Intraoperative measurements were performed by recording the smallest hole the graft could fit through at its widest point. Pearson's correlation coefficients were calculated to determine the relationship between graft size and tendon cross-sectional area. A simple logistic regression analysis was used to calculate the cutoff cross-sectional areas needed for a graft measuring at least 8 mm at its thickest point. Intrarater reliability was evaluated based on re-measurement of 19 tendons, which produced an overall intraclass correlation coefficient (ICC) of 0.96 95% (CI 0.93 to 0.98). A p value < 0.05 was considered significant. In general, the correlation between MRI-measured hamstring thickness and hamstring graft thickness as measured in the operating room were good but not excellent. The three measurements that demonstrated the strongest correlation with graft size in the 1.5 T group were the semitendinosus at the medial femoral condyle (r = 0.69; p < 0.001), the semitendinosus and gracilis at the medial femoral condyle (r = 0.70; p < 0.001), and the mean semitendinosus and gracilis (r = 0.64; p < 0.001). These three measurements had correlation values of 0.53, 0.56, and 0.56, respectively, in the 3 T MRI group (all p values < 0.001). To create an 8-mm hamstring autograft, the mean semitendinosus plus gracilis cutoff values areas were 18.8 mm and 17.5 mm for the 1.5 T and 3.0 T MRI groups, respectively. Imaging performed according to routine knee injury protocol can be used to preoperatively predict the size of hamstring autografts for ACL reconstructions. In clinical practice, this can assist orthopaedic surgeons in graft selection and surgical planning. Level II, diagnostic study.

The Kaplan Fibers of the Iliotibial Band Can Be Identified on Routine Knee Magnetic Resonance Imaging

Background: The Kaplan fibers (KFs) of the iliotibial band have been suggested to play a role in anterolateral rotational instability of the knee, particularly in the setting of an anterior cruciate ligament (ACL) rupture. Description of the normal magnetic resonance imaging (MRI) anatomy of the KFs may facilitate subsequent investigation into the MRI signs of injury. Purpose: To assess if the KF complex can be identified on 3-T MRI using standard knee protocols. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: 3-T MRI scans of 50 ACL-intact knees were reviewed independently by a musculoskeletal radiologist and 2 orthopaedic surgeons. Identification of the KFs was based on radiological diagnostic criteria developed a priori. Identification of the KFs in the sagittal, coronal, and axial planes was recorded. Interobserver reliability was assessed using the Kappa statistic. Detailed anatomy including distance to the joint line and relationship to adjacent structures was recorded. Results: The mean patient age was 43 years (range, 15-81 years), 58% were male, and 50% were right knees. The KFs were identified by at least 2 reviewers on the sagittal images in 96% of cases, on the axial images in 76% of cases, and on the coronal images in 4% of cases. The mean distance from the KF distal femoral insertion to the lateral joint line was 50.1 mm (SD, 6.6 mm) and the mean distance to the lateral gastrocnemius tendon origin was 10.8 mm (SD, 8.6 mm). The KFs were consistently identified immediately anterior to the superior lateral geniculate artery on sagittal imaging. Interobserver reliability for identification was best in the sagittal plane (Kappa 0.5) and worst in the coronal plane (Kappa 0.1). Conclusion: The KF complex can be identified on routine MRI sequences in the ACL-intact knee; however, there is low to moderate interobserver reliability. Imaging in the sagittal plane had the highest rate of identification and the coronal plane the lowest. There is a consistent relationship between the most distal KF femoral attachment and the lateral joint line, lateral gastrocnemius tendon, and superior lateral geniculate artery.

Predicting adequacy of free quadriceps tendon autograft, for primary and revision ACL reconstruction, from patients' physical parameters.

Free quadriceps tendon autograft (QTA) has gained popularity for both primary and revision ACL reconstruction. The aim of this study is to measure the dimensions of quadriceps tendon and determine its correlation with patient's height, weight and BMI. This is to provide a guide for patients and surgeons in predicting the suitability of QTA for ACL reconstructions. A cross-sectional study in which the length and thickness of the quadriceps tendon was measured in 51 Caucasian patients who underwent primary total knee arthroplasty. Exclusion criteria include non-Caucasians and previous tendon pathology. Patients were selected from routine elective total knee arthroplasty list. Tendon length is taken from musculotendinous junction to its insertion. Thickness was measured at midpoint and at distal insertion. Patients' height, weight and BMI were recorded. The correlation between patient physical parameters and tendon dimensions were determined. Subjects' median age was 65years (range 44-87), with 34 females and 17 males. Median length of the tendon was 9mm (range 70-110), and median insertional thickness was 9mm (7-10mm). Median thickness at midpoint was 7mm (range 4-10mm). There was moderately positive correlation between subjects' height and tendon length (correlation coefficient 0.50), and also between weight and tendon length (correlation coefficient 0.47). There was no significant correlation between subjects' BMI and the tendon length. There was also no significant correlation between tendon thickness and subject's physical parameters. This study has shown that most patients could provide adequate QTA for ACL reconstruction. It also points to the fact that no investigation is required to predict the adequacy of QTA. Though further studies with larger sample size are required to confirm this, clinician can rely on analysing patients' physical parameter in predicting the adequacy of QTA for ACL reconstruction. II.

The effects of extracorporeal shock wave therapy on the lower limb function and articular cartilage of patients with knee osteoarthritis

Objective To evaluate the effect and safety of extracorporeal shock wave therapy (ESWT) for knee osteoarthritis (KOA) and its effect on the articular cartilage. Methods Sixty-three persons with KOA were randomly divided into an ESWT group (n=32) and a control group (n=31). Both groups received routine knee muscle strength training, but the ESWT group was also given ESWT (a total of 2000 pulses at 8 Hz and 2.5 bar pressure) once a week for four consecutive weeks. The control group was given sham therapy at 0.2 bar with the rest of the parameters the same as in the ESWT group. All of the subjects were assessed using a visual analogue scale (VAS), the Western Ontario and McMaster Universities Osteoarthritis Score (WOMAC), the Lequesne Index and knee cartilage T2 values before as well as one and 8 weeks after the intervention. Results The average VAS score, WOMAC index, and Lequesne index of the ESWT group at 8 weeks after the treatment were significantly better than those before the intervention, and significantly better than the control group′s averages. The T2 values of the ESWT group at 8 weeks after the treatment were significantly better than before the intervention, though not significantly different from those of the control group at that point. No serious adverse reactions occurred in either group, and all of the minor adverse reactions had disappeared before the end of the assessment period. Conclusion ESWT can significantly improve the lower limb functioning of KOA patients, and its influence on knee cartilage is within the safe range. Key words: Extracorporeal shock wave therapy; Knee osteoarthritis; Lower limb function; Articular cartilage

Predictors of Pain and Function Before Knee Arthroscopy.

Background:Patient-reported outcome measures are commonly used to measure knee pain and functional impairment. When structural abnormality is identified on examination and imaging, arthroscopic partial meniscectomy and chondroplasty are commonly indicated for treatment in the setting of pain and decreased function.Purpose:To evaluate the relationship between patient characteristics, mental health, intraoperative findings, and patient-reported outcome measures at the time of knee arthroscopy.Study Design:Cross-sectional study; Level of evidence, 3.Methods:Between February 2015 and October 2016, patients aged 40 years and older who were undergoing routine knee arthroscopy for meniscal and cartilage abnormality, without reconstructive or restorative procedures, were prospectively enrolled in this study. Routine demographic information was collected, and the Knee injury and Osteoarthritis Outcome Score (KOOS) Pain, Quality of Life (QoL), and Physical Function Short Form (PS) subscales and the mental and physical component subscales of the Veterans RAND 12-Item Health Survey (VR-12 MCS and VR-12 PCS) were administered preoperatively on the day of surgery. Intraoperative findings were collected in a standardized format. Patient demographics, intraoperative findings, and the VR-12 MCS were used as predictor values, and a multivariate analysis was conducted to assess for relationships with the KOOS and VR-12 as dependent variables.Results:Of 661 eligible patients, baseline patient-reported outcomes and surgical data were used for 638 patients (97%). Lower scores on both subscales of the VR-12 were predicted by female sex, positive smoking history, fewer years of education, and higher body mass index (BMI). All KOOS subscales were negatively affected by lower VR-12 MCS scores, female sex, lower education level, and higher BMI in a statistically meaningful way. Positive smoking history was associated with worse scores on the KOOS-PS. Abnormal synovial status was associated with worse KOOS-Pain.Conclusion:The demographic factors of sex, smoking status, BMI, and education level had an overwhelming impact on preoperative KOOS and VR-12 scores. Of interest, mental health as assessed by the VR-12 MCS was also a consistent predictor of KOOS scores. The only intraoperative finding with a significant association was abnormal synovial status and its effect on KOOS-Pain scores.

Characterization of intramuscular calf vein thrombosis on routine knee MRI.

Literature regarding intramuscular calf vein thrombosis (IMCVT) or infrapopliteal deep vein thrombosis (DVT) evaluation by magnetic resonance imaging (MRI) is limited, particularly with regard to routine unenhanced knee examinations. We attempt to correlate routine unenhanced MRI findings with ultrasound evaluations of the lower extremity deep venous system. The radiology information system was searched, yielding a total of 67 patients who had undergone both routine knee MRI and duplex ultrasound examinations within 14days. The MRI examination findings recorded were the presence and pattern of edema, segmental vein dilation, intraluminal signal on fluid-sensitive sequences, and abnormal hyperintense signal on axial T1-weighted sequences. The presence and extent of thrombus more centrally (i.e., intramuscular calf vein thrombosis with or without extension into the popliteal vein) was reassessed on ultrasound. When comparing patients with positive (n = 13) and negative (n = 54) ultrasound, there were significant differences in each of these parameters: perivascular edema, intramuscular edema, focal vein dilation, and abnormal fluid-sensitive signal. In the subset of patients with popliteal extension of the intramuscular calf vein thrombosis compared with those without any deep vein thrombosis, there was a statistically significant increase in peripopliteal edema, abnormal fluid-sensitive signal, and abnormal hyperintense T1 signal. Imaging findings on routine unenhanced MRI have a high rate of concordance with duplex ultrasound performed through the calf in the detection of intramuscular calf vein thrombosis.

The incidence of infection in routine knee arthroscopy without the use of prophylactic antibiotics is low

Background: The use of prophylactic antibiotics in routine knee arthroscopy remains prevalent despite previous evidence suggesting that it may not be necessary, and may indeed carry more risks than benefits. This study aims to determine the incidence of surgical site infections in patients undergoing routine knee arthroscopy without prophylactic antibiotics. Methods: This is a retrospective review of 553 consecutive patients who underwent routine knee arthroscopy from 2004 to 2013 by a single fellowship-trained sports surgeon in a single institution. The spectrum of cases included arthroscopic meniscectomy, meniscal repair, microfracture, chondroplasty, removal of loose bodies and lateral retinacular release. No patient received any prophylactic antibiotics. Patient demographics and comorbidities were reviewed and all patients were followed up postoperatively for a minimum of two years. All postoperative complications were recorded. Results: There were 349 male and 204 female patients. The mean age was 41.8 years (SD 14.8) and mean operative time was 30.4 minutes (SD 12.3). Two healthy young patients developed postoperative superficial wound infection within one week after surgery, but recovered with outpatient oral antibiotic treatment. The overall infection rate was 0.36%. No cases of deep infection were reported. Conclusion: This study showed a very low rate of surgical site infections, comparable with known rates following such operations. This suggests that prophylactic antibiotics are not necessary and avoids the known risks associated with their use.

Targeted rapid knee MRI exam using T2 shuffling.

MRI is commonly used to evaluate pediatric musculoskeletal pathologies, but same-day/near-term scheduling and short exams remain challenges. To investigate the feasibility of a targeted rapid pediatric knee MRI exam, with the goal of reducing cost and enabling same-day MRI access. A cost effectiveness study done prospectively. Forty-seven pediatric patients. 3T. The 10-minute protocol was based on T2 Shuffling, a four-dimensional acquisition and reconstruction of images with variable T2 contrast, and a T1 2D fast spin-echo (FSE) sequence. A distributed, compressed sensing-based reconstruction was implemented on a four-node high-performance compute cluster and integrated into the clinical workflow. In an Institutional Review Board-approved study with informed consent/assent, we implemented a targeted pediatric knee MRI exam for assessing pediatric knee pain. Pediatric patients were subselected for the exam based on insurance plan and clinical indication. Over a 2-year period, 47 subjects were recruited for the study and 49 MRIs were ordered. Date and time information was recorded for MRI referral, registration, and completion. Image quality was assessed from 0 (nondiagnostic) to 5 (outstanding) by two readers, and consensus was subsequently reached. A Wilcoxon rank-sum test assessed the null hypothesis that the targeted exam times compared with conventional knee exam times were unchanged. Of the 49 cases, 20 were completed on the same day as exam referral. Median time from registration to exam completion was 18.7 minutes. Median reconstruction time for T2 Shuffling was reduced from 18.9 minutes to 95 seconds using the distributed implementation. Technical fees charged for the targeted exam were one-third that of the routine clinical knee exam. No subject had to return for additional imaging. The targeted knee MRI exam is feasible and reduces the imaging time, cost, and barrier to same-day MRI access for pediatric patients. 2 Technical Efficacy: Stage 6 J. Magn. Reson. Imaging 2019.

Effectiveness of Negative-Pressure Wound Therapy following Total Hip and Knee Replacements.

In this review, we assess the effects of negative-pressure wound therapy (NPWT) following primary hip and knee replacement surgery with a systematic review of randomized controlled trials (RCTs). We searched the Cochrane Bone, Joint, and Muscle Trauma Group's Specialized Registry on June 12, 2018; the Cochrane Central Register of Controlled Trials (CENTRAL, 2018, Issue 1); Ovid MEDLINE (1946-2018); and Embase (1980-2018). To identify RCTs, we combined a subject-specific search strategy with a sensitivity-maximizing version of the Cochrane highly sensitive search strategy. Included were RCTs and quasi-RCTs that compare NPWT with other treatments or no treatment following primary hip and knee replacements. We excluded trials that were focused on patients undergoing revision hip or knee replacements or who had pathological bone disease or periprosthetic fractures. Five RCTs met the inclusion criteria and are included in this review, making a total of 382 patients with primary total hip/knee replacements. Included trials were of varying quality, with little consistency in control groups or outcome measures; therefore, a meta-analysis could not be performed. Overall, three RCTs reported no significant differences in primary outcomes after NPWT, in comparison to standard or conventional wound care. One trial reported significant reduction in wound seroma size in patients undergoing primary hip replacements after NPWT, compared to standard dressings (NPWT, 1.97 vs. 5.08 mL [p = 0.021]; n = 19). Finally, one trial that compared NPWT with standard dressings following primary hip/knee replacements (n = 209) reported statistically significant differences that favored NPWT for overall reduction in length of hospital stay (mean difference, 0.9 d, 95% confidence interval [CI], -0.2-2.5; p = 0.07), number of dressing changes (mean difference, 1.7; 95% CI, 0.8-2.5; p = 0.002), and a fourfold reduction in reported postoperative surgical wound complications (8.4% vs. 2.0%; p = 0.06). Cost-effectiveness quality adjusted life years showed greater savings for higher-risk patients (body mass index ≥ 35; ASA ≥ 3). We find no justification for applying NPWT to all postoperative wounds after routine total hip and knee replacement; however, NPWT may benefit selected patients who are at high risk for wound complications.

Magnetic resonance imaging of the quadriceps fat pad oedema pattern in relation to patellofemoral joint pathologies.

PurposeQuadriceps fat pad is located posterior to the quadriceps tendon. Increased signal intensity of this fat pad is seen on routine knee magnetic resonance imaging (MRI) examinations, but the exact mechanism and related pathologies are not clear. In this study we aimed to evaluate the relationship between MRI signal intensity and morphological features of quadriceps fat pad, as well as various pathologies of the patellofemoral joint.Material and methodsSixty-one knees with quadriceps fat pad oedema out of 457 knee MRI examinations were included. Quadriceps fat pad signal intensity, dimensions, posterior indentation, and various parameters related to patellofemoral joint such as trochlear facet asymmetry, trochlear depth and sulcus angle, and the Insall-Salvati ratio were evaluated.ResultsThere was no statistically significant correlation between quadriceps fat pad oedema intensity and its dimensions, but it was significant when compared to posterior indentation. There was no correlation between fat pad oedema and each of the pathologies. However, there was a significant correlation between the presence of fat pad oedema and the presence of at least one of the pathologies related to patellofemoral joint.ConclusionsQuadriceps fat pad oedema detected in MRI examinations should warn the radiologist against the presence of various pathologies related to the patellofemoral joint.

Combined 5-minute double-echo in steady-state with separated echoes and 2-minute proton-density-weighted 2D FSE sequence for comprehensive whole-joint knee MRI assessment.

Clinical knee MRI protocols require upwards of 15 minutes of scan time. To compare the imaging appearance of knee abnormalities depicted with a 5-minute 3D double-echo in steady-state (DESS) sequence with separate echo images, with that of a routine clinical knee MRI protocol. A secondary goal was to compare the imaging appearance of knee abnormalities depicted with 5-minute DESS paired with a 2-minute coronal proton-density fat-saturated (PDFS) sequence. Prospective. Thirty-six consecutive patients (19 male) referred for a routine knee MRI. DESS and PDFS at 3T. Five musculoskeletal radiologists evaluated all images for the presence of internal knee derangement using DESS, DESS+PDFS, and the conventional imaging protocol, and their associated diagnostic confidence of the reading. Differences in positive and negative percent agreement (PPA and NPA, respectively) and 95% confidence intervals (CIs) for DESS and DESS+PDFS compared with the conventional protocol were calculated and tested using exact McNemar tests. The percentage of observations where DESS or DESS+PDFS had equivalent confidence ratings to DESS+Conv were tested with exact symmetry tests. Interreader agreement was calculated using Krippendorff's alpha. DESS had a PPA of 90% (88-92% CI) and NPA of 99% (99-99% CI). DESS+PDFS had increased PPA of 99% (95-99% CI) and NPA of 100% (99-100% CI) compared with DESS (both P < 0.001). DESS had equivalent diagnostic confidence to DESS+Conv in 94% of findings, whereas DESS+PDFS had equivalent diagnostic confidence in 99% of findings (both P < 0.001). All readers had moderate concordance for all three protocols (Krippendorff's alpha 47-48%). Both 1) 5-minute 3D-DESS with separated echoes and 2) 5-minute 3D-DESS paired with a 2-minute coronal PDFS sequence depicted knee abnormalities similarly to a routine clinical knee MRI protocol, which may be a promising technique for abbreviated knee MRI. 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018.

Magnetic resonance imaging for common peroneal nerve injury in trauma patients: Are routine knee sequences adequate for prediction of outcome?

Common peroneal nerve (CPN) injury occurs in 10-40% of patients following knee dislocation. Is magnetic resonance imaging (MRI) using routine knee protocols able to adequately evaluate CPN injury and predict long-term outcome? Trauma patients presenting for knee MRI at a single public hospital, between July 2007 and May 2017, were retrospectively identified using radiology and orthopaedic databases. Medical records were retrieved for clinical scores. MRI images were scored by two independent radiologists blinded to the clinical CPN status and scores correlated with initial clinical scores using the Pearson correlation coefficient. Final cohort included 107 patients (81 males and 26 females) with a mean age of 39 (range 19-81years). MRI was considered to be adequate for coverage of the CPN in 84 patients. Fourteen patients had CPN injury clinically (seven complete and seven partial). Concordance between MRI scores and initial clinical scores was 0.456 (P=0.01). MRI sensitivity and specificity for CPN injury on the 84 adequate scans were 54.5% and 93.2% respectively. All seven cases of partial CPN injury and three of seven cases of complete CPN injury recovered fully. High MRI scores of 5 and 8 were given for the two patients with a persisting complete CPN palsy. Highest scores for partial CPN injury subjects were 2 and 4. Magnetic resonance imaging using a routine knee protocol is not adequate for the assessment of CPN injury in many subjects. More specific MRI neural sequences with complete CPN coverage may be worth trialing.

Blood Flow-Restricted Training for Lower Extremity Muscle Weakness due to Knee Pathology: A Systematic Review.

Context:Blood flow–restricted training (BFRT) has been suggested to treat lower extremity muscle weakness. The efficacy of BFRT for muscle problems related to knee pathology is unclear.Objective:To determine whether BFRT (1) improves muscle strength and cross-sectional area (CSA) for chronic knee-related lower extremity atrophy and (2) prevents muscle atrophy after knee surgery.Data Sources:A systematic review of the literature from 1974 to 2017 was conducted using the PubMed and Cochrane databases.Study Selection:Controlled trials that used BFRT to treat chronic knee-related lower extremity muscle atrophy or to prevent muscle atrophy after knee surgery that measured the effects on quadriceps or hamstrings muscle strength or CSA were included.Study Design:Systematic review.Level of Evidence:Level 2.Data Extraction:Data were extracted as available from 9 studies (8 level 1, 1 level 2). Assessment of study quality was rated using the Physiotherapy Evidence Database or Methodological Index for Non-Randomized Studies instruments.Results:BFRT was used after anterior cruciate ligament reconstruction and routine knee arthroscopy and in patients with knee osteoarthritis or patellofemoral pain. There were a total of 165 patients and 170 controls. Vascular occlusion and exercise protocols varied; all studies except 1 incorporated exercises during occlusion, most of which focused on the quadriceps. Six of 7 studies that measured quadriceps strength reported statistically significant improvements after training. Few benefits in quadriceps CSA were reported. Hamstrings strength was only measured in 2 studies. There were no complications related to training.Conclusion:Published limited data show BFRT to be safe and potentially effective in improving quadriceps muscle strength in patients with weakness and atrophy related to knee pathology. The use of short-duration vascular occlusion and light-load resistance exercises appears safe after knee surgery or in arthritic knees. This treatment option requires further investigation to refine protocols related to cuff pressure and exercise dosage and duration.

Interpretations of the dial test should be reconsidered. A diagnostic accuracy study reporting sensitivity, specificity, predictive values and likelihood ratios

ObjectivesTo determine the accuracy of the dial test, used alone and in combination with additional clinical tests, in the diagnosis of an isolated posterolateral corner (PLC) injury, combined PLC-posterior cruciate ligament (PCL) injury or medial knee injury.MethodsA retrospective analysis of consecutive patients who underwent arthroscopic and/or open knee ligament reconstruction surgery was conducted. The dial test was performed in an outpatient’s clinic as part of a routine knee examination. Examination under anaesthetic and intraoperative findings were used as the reference standard test to determine the diagnostic accuracy of the dial test used alone and in combination with other PCL and medial knee tests. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (LR+) and negative likelihood ratio (LR−) were calculated with corresponding 95% CI.ResultsData from 87 patients were available and included in the data analysis. For an isolated PLC injury, the dial test sensitivity and specificity were 0.20 (95% CI 0.08 to 0.39) and 1.00 (95% CI 0.92 to 1.00). The PPV and NPV were 1.00 (95% CI 0.52 to 1.00) and 0.70 (95% CI 0.59 to 0.80). LR+ and LR− of the dial test detecting isolated PLC injury were infinity (95% CI calculation not possible, infinity) and 0.80 (95% CI 0.41 to 1.57). The diagnostic accuracy of the dial test, when used alone and in combination with other PCL and medial knee tests, was also calculated for combined PLC-PCL and medial knee injuries.ConclusionA negative dial test at 30° of knee flexion can rule out a PLC injury, while a test that is positive at 30° and negative at 90° indicates a PLC injury, without concomitant injury to the PCL or medial knee ligaments. A positive test at both 30° and 90° can indicate isolated PLC, combined PLC-PCL or medial ligament injuries, and other knee examination findings are required to differentially diagnose these injury patterns.Level of evidenceII.

Primary and Secondary Total Knee Arthroplasty for Tibial Plateau Fractures.

The surgical management of tibial plateau fractures can be technically demanding. In younger patients, the mainstay is fixation with cartilage preservation. In older patients with osteoporotic bone, this method has higher rates of fixation failure; in addition, it requires prolonged bed rest or protected weight bearing, which are major challenges in this group. In contrast, total knee arthroplasty performed acutely for primary treatment of tibial plateau fractures has potential advantages for elderly patients, such as immediate stability, early mobilization, and positive functional outcomes with decreased rates of reoperation. Additionally, arthroplasty can be technically challenging in younger patients with previous tibial plateau fractures in whom debilitating posttraumatic arthritis develops. In these patients, old wounds, retained metalwork, bony deficiency, and instability can lead to poorer outcomes and higher complication rates than in routine knee arthroplasty. In both cases, we recommend surgery be performed by experienced arthroplasty surgeons with ample access to a range of implants with varying constraints and the option of stems and augments.

Value of antibiotic prophylaxis in routine knee arthroscopy : Aretrospective study.

Prophylactic antibiotic use prior to routine knee arthroscopy remains controversial. It is important to know whether antibiotics help decrease the surgical site infection (SSI) rate. Our aims were to assess the efficacy of antibiotic prophylaxis in preventing SSI and to identify risk factors for SSI following routine knee arthroscopy without an implant. Aretrospective study was conducted using the electronic medical records at the authors' hospital to identify patients that underwent routine knee arthroscopy without an implant between October 2010 and October 2016. Data on demographics, clinical characteristics and antibiotic administration were extracted. Arthroscopic diagnosis, debridement, partial or complete meniscectomy, arthroscopic shaving and microfracture, removal of loose bodies, synovectomy and lateral retinacular release were included. Complex knee arthroscopy with an implant was excluded. Patients were divided into evaluation (with prophylactic antibiotics) and control (no antibiotic treatment) groups. Continuous variables between groups were compared using the Student's t-test. Data were analyzed using the Chi-squared test for percentages between groups. Multivariate logistic regression was used to identify independent risk factors of SSI. Of 1326 patients, 614 (46.3%) received prophylactic antibiotics, while 712 (53.7%) did not. There were seven (0.53%) SSIs. The SSI rate did not differ significantly between patients receiving antibiotics (0.49%, three) and those not (0.56%, four). Five patients (0.37%) had superficial infections, two (0.33%) were in the prophylactic antibiotic group and three (0.42%) were in the other group. Deep infections occurred in two patients (0.15%), one (0.16%) in the prophylactic antibiotic group and one (0.14%) in the other group. The difference between the two groups was not statistically significant (P= 1.0). Age over 50years was associated with an increased risk of SSI (relative ratio [RR]= 1.469, 95% confidence interval [CI] 1.09-2.13, P= 0.009). Prophylactic antibiotic use in routine knee arthroscopy without an implant may not be necessary. Age over 50years was associated with an increased risk of SSI.