Noise around the Knee

MRI sequences at different degrees of flexion to investigate knee popping: an unusual way to diagnose an isolated pigmented villonodular synovitis lesion

Knee popping is a frequent symptom among knee disorders which requires further investigation in case of a recent evolution of the symptom or pathological associated ones. This article reports a rare presentation of pigmented villonodular synovitis (PVNS), identified as the cause of knee popping symptoms, by performing MRI sequences at various degrees of knee flexion for a patient complaining from a gradual onset of knee popping, occurring when bending the knee over 120° of flexion. MRI sequences were performed just before the popping occurs (flexion 90°) and right after it had occurred (flexion 120°). The latter confirmed the origin of the symptom as the lesion moved forward, passing brutally through the interstice between the PCL and the ACL at 120° of flexion, explaining the popping. Treatment decision was to perform an arthroscopic resection of the lesion. Diagnosis of isolated PVNS was confirmed after anatomopathological analysis.

Factors influencing correction rate following hemiepiphysiodesis using tension band plates for deformities around the knee: a multivariate analysis study

PURPOSE

The aim of this study was to appraise various factors influencing the correction rate in temporary hemiepiphysiodesis (THE) around the knee joint. Specifically, the study analysed the relationship of correction rate with age, gender, aetiology, type and location of deformity.

METHODS

The retrospective study included children who underwent THE for a coronal plane deformity (genu valgus or varum) around the knee joint (distal femur or proximal tibia) over a ten year period (2010-2020). The primary outcome of interest was the correction rate of the deformity.

RESULTS

Thirty-three children (27 females and 6 males) with a mean age of 8.1 years involving 86 plates were included in the study. The mean correction achieved was 12.2° over a treatment period of 13.3 months. Subgroup analysis showed significant differences between the type (varus (0.8° per month), valgus (1.1° per month)) and the location of deformity femur (1.2° per month) and tibia (0.7° per month)]. On multivariate analysis, the location and the duration of treatment showed significant associations with the correction rate.

CONCLUSION

The correction of coronal deformities following temporary hemiepiphysiodesis is influenced by several factors. Valgus, femoral and deformities in younger children correct at a faster rate. Location of deformity and duration of treatment emerged as potential factors affecting the correction rate.

Creaky knees: Is there a reason for concern? A qualitative study of the perspectives of people with knee crepitus

OBJECTIVE

Crepitus is a feature of osteoarthritis that may affect one's participation in exercise. An informed understanding is required of the perceptions that people have of their knee crepitus and how it affects their exercise behaviours. This study aims to investigate the role that crepitus may play in beliefs about exercise and knee health.

METHODS

Focus group and individual interviews were conducted online with participants who had knee crepitus. The transcripts were thematically analysed through an inductive approach.

RESULTS

Five main themes were identified from 24 participants: (1) individual variation of, (2) occurrence of, (3) meaning of knee crepitus, (4) attitudes and exercise behaviours regarding crepitus, and (5) knowledge deficits and needs concerning crepitus during exercise. The variety of crepitus sounds described occurred with a range of exercises or after inactivity. For those already with osteoarthritis or other symptoms, crepitus was of less concern than symptoms such as pain. Most participants had not ceased exercise but may have modified movement due to crepitus and associated symptoms; some had increased intentional strength training to try alleviating it. Participants agreed that more understanding about the processes causing crepitus and what exercise was safe for knee health would be beneficial.

CONCLUSION

Crepitus does not appear to be a major cause of concern for people who experience it. However, it is a factor that influences exercise behaviours as is pain. If health professionals could guide people with concerns about their crepitus, they may be more confident in exercising to benefit their joint health.

Modern implants in total knee arthroplasty are more patellofemoral joint friendly compared to their traditional design: a systematic review and meta-analysis

BACKGROUND

Implant designs for total knee arthroplasties (TKA) are continuously evolving to improve outcomes and satisfaction rates after TKA. The present systematic review and meta-analysis aimed to explore the evidence in the literature regarding the outcomes of the Attune knee system over the PFC Sigma knee design and investigate the advantage of one over the other.

METHODS

A systematic review and meta-analysis of published studies till August 2021 was performed using the defined eligibility criteria. This was a systematic review of the literature published in the Cochrane Central Register of Controlled Trials (CENTRAL) Library, PUBMED, and EMBASE. The analysis included prospective and retrospective comparative trials comparing TKA by PFC sigma or Attune posterior stabilized (PS) or cruciate-retaining (CR), fixed bearing, or rotating platform systems. Patient-reported outcome measures (PROM) and postoperative patellar complications were analysed in the studies utilizing attune knee system (modern implants) to its counterpart PFC sigma (traditional implants) for TKA. Quality assessment was conducted using NIH Quality Assessment Tool for controlled intervention studies (RCTs and case-control studies).

RESULTS

This review included 3 RCTs and the rest, 10 of which were non-RCT, including 5852 patients. ATTUNE designs suggested a statistically significant improvement in KSS over PFC Sigma designs. Other PROMs such as OKS and WOMAC scores yielded comparable results between the two groups. ATTUNE knee prosthesis did not result in better knee range of motion, patient satisfaction, or radiological outcomes than the PFC design. Regarding the complications, attune knee prosthesis demonstrated favourable results over PFC Sigma for anterior knee pain and patellofemoral (PF) crepitus.

CONCLUSIONS

The present systematic review highlights better KSS and lesser chances of PF complications favouring a modern implant design over its traditional counterpart. Other patient-reported outcome analyses at a short-term follow-up period were comparable among patients undergoing total knee replacements with two different implant designs. Radiological outcomes for component positioning also suggested similar results among the two groups.

A Feasibility Study on Tribological Origins of Knee Acoustic Emissions

OBJECTIVE

Considering the knee as a fluid-lubricated system, articulating surfaces undergo different lubrication modes and generate joint acoustic emissions (JAEs) while moving. The goal of this study is to compare knee biomechanical signals against synchronously recorded joint sounds and assess the hypothesis that these JAEs are attributed to tribological origins.

METHODS

JAE, electromyography, ground reaction force signals, and motion capture markers were synchronously recorded from 10 healthy subjects while performing two-leg and one-leg squat exercises. The biomechanical signals were processed with standard inverse dynamic analysis through musculoskeletal modeling, and a tribological parameter, lubrication coefficient, was calculated from these signals. Besides, JAEs were divided into short windows, and 64 time-frequency features were extracted. The lubrication coefficients and joint sound features of the two-leg squats were used to label the windows and train a classifier that discriminates the knee lubrication modes only based on JAE features. Then, the classifier was used to predict the label of one-leg squat JAE windows. To evaluate these results, the predicted joint sound labels were directly compared against the associated lubrication coefficients.

RESULTS

The trained classifier achieves a high test-accuracy of 84% distinguishing lubrication modes of the one-leg squat JAE windows. The Pearson correlation coefficient between the estimated friction coefficient and the predicted JAE scores was 0.830.08. Furthermore, the lubrication coefficient threshold, separating two lubrication modes, was calculated from joint sound labels, and it decreased by half from two-leg to one-leg squats. This result was consistent with the tribological changes in the knee load as it was inversely doubled in one-leg squats. These results verify that JAEs contain salient information on knee tribology.

SIGNIFICANCE

This study supports the potential use of JAEs as a quantitative digital biomarker to extract tribological information about joint lubrication modes and loading conditions. Since arthritis and many other conditions impact the roughness of cartilage and other surfaces within the knee, the use of JAEs in clinical applications could thereby have broad implications for studying joint frictions and monitoring joint structural changes with wearable devices.

Effects of Viscosupplementation on Quality of Knee Joint Arthrokinematic Motion Analyzed by Vibroarthrography

OBJECTIVE

To evaluate the influence of viscosupplementation on osteoarthritic knee arthrokinematics analyzed by VAG. It is considered that intra-articular hyaluronic acid injection may improve the function of synovial joints by recovery of friction-reducing properties of articular environment.

DESIGN

Thirty-five patients with knee osteoarthritis (grade II according to the Kellgren-Lawrence system) and 50 asymptomatic subjects were enrolled in the study. Patients were analyzed at 3 time points: 1 day before and 2 weeks and 4 weeks after single injection of 1.5% cross-linked hyaluronate. Control subjects were tested once. The vibroarthrographic signals were collected during knee flexion/extension motion using an accelerator and described by variation of mean square (VMS), mean range (R5), and power spectral density for frequency of 50 to 250 Hz (P1), and 250 to 450 Hz (P2).

RESULTS

Patients before viscosupplementation were characterized by about 2-fold higher values of vibroarthrographic parameters than controls. Two weeks after the procedure, the values of R5, P1, and P2 significantly decreased, in comparison to pre-injection. At 4 weeks post-injection, we noted a significant increase in R5, P1, and P2 values, when compared to 2 weeks post-injection. Finally, at 4 weeks post-injection, the level of VMS, R5, and P2 parameters did not differ from values obtained at pre-injection.

CONCLUSIONS

We showed that viscosupplementation may be effective in providing arthrokinematics improvement, but with a relatively short period of duration. This phenomenon is observed as decreased vibroacoustic emission, which reflects a more smooth movement in the joint.

The Assessment of the Condition of Knee Joint Surfaces with Acoustic Emission Analysis

The knee joint, being the largest joint in the human body, is responsible for a great percentage of leg movements. The diagnosis of the state of knee joints is usually based on X-ray scan, ultrasound imaging, computerized tomography (CT), magnetic resonance imaging (MRI), or arthroscopy. In this study, we aimed to create an inexpensive, portable device for recording the sound produced by the knee joint, and a dedicated application for its analysis. During the study, we examined fourteen volunteers of different ages, including those who had a knee injury. The device effectively enables the recording of the sounds produced by the knee joint, and the spectral analysis used in the application proved its reliability in evaluating the knee joint condition.

Risk Factors for Patellar Clunk or Crepitation after Primary Total Knee Arthroplasty: A Systematic Review and Meta-analysis

Patellar clunk and crepitation (PCC) have been reported as a consequence of primary total knee arthroplasty (TKA). The incidence and contributing factors have not been fully defined. We performed this systematic review to evaluate factors associated with PCC following primary TKA. We identified studies on PCC following TKA from an electronic search of articles in Medline, Embase and the Cochrane databases (dated up to May 2018). Eighteen studies altogether, including 600 cases of PCC within 8,131 TKAs, were included in the meta-analysis. Several factors including demographic, intraoperative, clinical variables, and radiographic measurements were pooled for meta-analysis. Among intraoperative and clinical variables, patients involved with patellar retention (odds ratio [OR] = 9.420; confidence interval [CI]: 5.770-13.070), lateral reticular release (OR = 2.818; CI: 1.114-7.125), and previous surgery (OR = 2.724; CI: 1.549-4.790) were more likely to having PCCs. Among radiographic measurements, increased anterior tibial offset (weighted mean difference [WMD] = 0.387; CI: 0.139-0.634), increased joint line changes (WMD = 1.325; CI: 0.595-2.055), and increased knee flexion angle (WMD = 3.592; CI: 1.811-5.374) were considered risk factors associated with PCC. Demographic factors (age, gender, body mass index [BMI], and diagnosis) and other reported radiographic measurements were not associated with PCCs. This study identified intraoperative variables (patellar retention and lateral reticular release), clinical variables (previous surgery), and radiographic measurements (increased anterior tibial offset, increased joint line changes, and increased postoperative knee flexion angle) that contribute to an increased risk for PCC. Modifiable factors (patellar retention and lateral reticular release) should be considered and addressed to limit the risk for PCC following TKA. Patients with conditions that may not be modifiable may benefit from counseling about their increased risks for PCC to limit potential dissatisfaction with their procedure.

Comparison of Joint Perception Between Posterior-Stabilized and Ultracongruent Total Knee Arthroplasty in the Same Patient

BACKGROUND

Posterior-stabilized and ultracongruent designs are 2 common examples of posterior cruciate ligament-substituting total knee arthroplasty (TKA) prostheses. There is a lack of evidence regarding joint perception differences between ultracongruent and posterior-stabilized TKA. The purpose of this study was to compare the postoperative knee stability, function, and joint perception between ultracongruent and posterior-stabilized TKA in the same patients in order to determine whether there was a difference based on design.

METHODS

This prospective, randomized controlled trial included 50 patients who underwent same-day bilateral TKA utilizing Persona (Zimmer Biomet) posterior-stabilized implants in 1 knee (posterior-stabilized group) and ultracongruent implants in the other knee (ultracongruent group). At 2 years postoperatively, patients were evaluated for knee stability, function, and joint perception. Postoperative static knee anteroposterior stability and femoral rollback were compared. Knee function was evaluated with use of the Knee Society Score and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Joint perception was compared by evaluating noise generation, side preference, satisfaction, and the Forgotten Joint Score.

RESULTS

The ultracongruent group had more knee anteroposterior laxity (4.5 mm compared with 1.8 mm in the posterior-stabilized group; p < 0.001) and less femoral rollback (4.2 mm compared with 9.0 mm in the posterior-stabilized group; p < 0.001). Knee Society Score and WOMAC scores were not significantly different between groups (all p > 0.05). Although the ultracongruent group showed less noise generation than the posterior-stabilized group (18% compared with 38%, respectively; p = 0.026), there were no differences in side preference, satisfaction, or Forgotten Joint Score (all p > 0.05).

CONCLUSIONS

Both groups had similar joint perception 2 years postoperatively, with obvious differences in noise generation and more sagittal laxity with less femoral rollback in the ultracongruent group.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Women with patellofemoral pain and knee crepitus have reduced knee flexion angle during stair ascent

OBJECTIVES

To compare trunk and knee biomechanics of women with and without patellofemoral pain (PFP) and knee crepitus during stair ascent.

DESIGN

Cross-sectional.

SETTING

Laboratory-based study.

PARTICIPANTS

29 women with PFP and knee crepitus (PFP_Crepitus); 28 women with PFP and no knee crepitus (PFP_NOCrepitus); 17 pain-free women with knee crepitus (Pain-free_Crepitus); and 29 pain-free women without knee crepitus (Pain-free_NOCrepitus).

MAIN OUTCOME MEASURES

Peak trunk flexion, peak knee flexion, mean knee angular velocity, knee extensor moment at peak knee flexion, peak and impulse of the knee extensor moment.

RESULTS

PFP_Crepitus group performed the stair ascent task with reduced peak knee flexion compared to Pain-free_Crepitus (p = 0.04; Effect size = -0.85) and Pain-free_NOCrepitus (p = 0.03; Effect size = -0.75). No significant differences among groups were found for peak trunk flexion (p = 0.979), knee angular velocity (p = 0.420), knee extensor moment at peak knee flexion (p = 0.933), peak (p = 0.290) and impulse (p = 0.122) of the knee extensor moment.

CONCLUSION

Women with concomitant PFP and knee crepitus demonstrated reduced knee flexion during stair ascent, but no significant differences for trunk flexion and knee extensor moment variables were found.

Affecting Factors and Correction Ratio in Genu Valgum or Varum Treated with Percutaneous Epiphysiodesis Using Transphyseal Screws

This study evaluated the correction rates of idiopathic genu valgum or varum after percutaneous epiphysiodesis using transphyseal screws (PETS) and analyzed the affecting factors. A total of 35 children without underlying diseases were enrolled containing 64 physes (44 distal femoral (DT), 20 proximal tibial (PT)). Anatomic tibiofemoral angle (aTFA) and the mechanical axis deviation (MAD) were taken from teleroentgenograms before PETS surgery and screw removal. The correction rates of the valgus and varus deformities for patients treated with PETS were 1.146°/month and 0.639°/month using aTFA while using MAD showed rates of 4.884%/month and 3.094%/month. After aTFA (p < 0.001) and MAD (p < 0.001) analyses, the correction rate of DF was significantly faster than that of PT. Under multivariable analysis, the aTFA correction rate was significantly faster in younger patients (p < 0.001), in males (p < 0.001), in patients with lower weights (p < 0.001), and in the group that was screwed at DF (p < 0.001). Meanwhile, the MAD correction rate was significantly faster in patients with lower heights (p = 0.003). PETS is an effective treatment method for valgus and varus deformities in growing children and clinical characters should be considered to estimate the correction rate.

Clinical Outcomes of a Modern Total Knee Arthroplasty Prosthesis Compared to Its Predecessor at 5-Year Follow-Up: Matched Pair Analysis

BACKGROUND

Residual pain is an important cause of patient dissatisfaction after total knee arthroplasty (TKA). A recent study at our institution found that a modern prosthesis was associated with less residual and anterior knee pain at 2-year follow-up when compared to its predecessor. The aim of this study is to evaluate these implants at 5-year follow-up.

METHODS

From July 2012 to December 2013, 100 consecutive modern TKAs were identified from our prospective Institutional Review Board approved database. All patients with 5-year clinical follow-up (n = 77) were matched in a one-to-one fashion based on age, gender, body mass index, and follow-up with a predecessor TKA. Clinical outcomes were assessed with a patient-administered questionnaire for specifically anterior knee pain, painless noise, painful crepitation, and satisfaction. Overall function was assessed using Knee Society Scores and Western Ontario and McMaster University Osteoarthritis Index.

RESULTS

At 5-year follow-up, there were no significant differences between the modern TKA and a predecessor TKA in the Knee Society pain or function scores (P = .24 and P = .54, respectively). The overall prevalence of residual pain was less with the modern TKA compared to its predecessor (19.5% vs 36.3%; P = .02), but the prevalence of isolated anterior knee pain was similar in both cohorts (11.7% vs 22.1%; P = .09). There was no difference in painless noise (19.5% vs 13.3%; P = .28) or satisfaction scores (7.9 ± 2.4 vs 7.6 ± 2.6; P = .25) between the modern and predecessor cohorts.

CONCLUSION

At 5-year follow-up, we found that both the modern and predecessor prostheses provided excellent clinical outcomes. The modern TKA was associated with less residual pain compared to its predecessor, but we were unable to detect differences in the prevalence of isolated anterior knee pain, painless noise, Knee Society Scores, or radiographic evaluation.

Reprint of "The detection of knee joint sounds at defined loads by means of vibroarthrography"

BACKGROUND

Crepitus of the knee may mirror structural and functional changes in the joint during motion. Although the magnitude of these sounds increases with greater cartilage damage, it is unclear whether knee joint sounds also reflect joint loading.

METHODS

Twelve healthy volunteers (mean 26 (SD 3.6) years, 7 females) participated in the randomized-balanced crossover study. Knee joint sounds were recorded (linear sampling, 5512 Hz) by means of two microphones, one placed on the medial tibial plateau and one on the patella. Two activities of daily living (standing up from/sitting down on a bench; descending stairs) and three open kinetic chain knee extension-flexion cycles (passive movement, 10% and 40% loading of the individual one repetition maximum) were performed. Each participant carried out three sets of five repetitions and three sets of 15 steps downwards (stairs), respectively. For data analysis, the mean sound amplitude and the median power frequency for each loading condition were determined. Friedman test and Bonferroni-Holm adjusted post-hoc test were performed to detect differences between conditions.

FINDINGS

We obtained significant differences between joint sound amplitudes for all movements, both measured at the medial tibial plateau (Chi² = 20.7, p < 0.001) and at the patella (Chi² = 27.6, p < 0.001). We showed a significant difference in the median power frequency of the patella between all movements (Chi² = 17.8, p < 0.5).

INTERPRETATION

Overall, the larger the supposed knee joint loading was, the louder was the recorded knee crepitus. Consequently, vibroarthrographically assessed knee joint sounds can differ across knee joint loading conditions.

Validity of and recommendations for knee joint acoustic assessments during different movement conditions

Knee joint sounds contain information on joint health, morphology and loading. These acoustic signals may be elicited by further, as yet unknown factors. By assessing potential elicitors and their relative contributions to the acoustic signal, we investigated the validity of vibroarthrographic assessments during different movement conditions with the aim to derive recommendations for their practical usage. Cross-sectional study. Nineteen healthy participants (24.7 ± 2.8 yrs, 7 females) performed five movements: level walking, descending stairs, standing up, sitting down, and forward lunge. Knee joint sounds were recorded by two microphones (medial tibial plateau, patella). Knee joint kinematics and ground reaction forces were recorded synchronously to calculate knee joint moments (Nm/Kg). The mean amplitude (dB) and the median power frequency (Hz) were determined. A repeated measures mixed model investigated the impact of potential predictors (sagittal, frontal, transverse plane and total knee joint moments, knee angular velocity, age, sex, body mass index (BMI) and Tegner Activity Score (TAS)). Most of the amplitudes variance is explained by between-subject differences (tibia: 66.6%; patella: 75.8%), and of the median power frequencies variance by the movement condition (tibia: 97.6%; patella: 98.9%). The final model revealed several predictor variables for both sensors (tibia: sagittal plane, frontal plane, and total knee joint moments, age, and TAS; patella: sagittal plane knee moments, knee angular velocity, TAS). The standardization of the execution of the activities, a between-group matching of variables and the inclusion of co-variates are recommended to increase the validity of vibroarthrographic measurements during different movement conditions of the knee joint.

The detection of knee joint sounds at defined loads by means of vibroarthrography

BACKGROUND

Crepitus of the knee may mirror structural and functional changes in the joint during motion. Although the magnitude of these sounds increases with greater cartilage damage, it is unclear whether knee joint sounds also reflect joint loading.

METHODS

Twelve healthy volunteers (mean 26 (SD 3.6) years, 7 females) participated in the randomized-balanced crossover study. Knee joint sounds were recorded (linear sampling, 5512 Hz) by means of two microphones, one placed on the medial tibial plateau and one on the patella. Two activities of daily living (standing up from/sitting down on a bench; descending stairs) and three open kinetic chain knee extension-flexion cycles (passive movement, 10% and 40% loading of the individual one repetition maximum) were performed. Each participant carried out three sets of five repetitions and three sets of 15 steps downwards (stairs), respectively. For data analysis, the mean sound amplitude and the median power frequency for each loading condition were determined. Friedman test and Bonferroni-Holm adjusted post-hoc test were performed to detect differences between conditions.

FINDINGS

We obtained significant differences between joint sound amplitudes for all movements, both measured at the medial tibial plateau (Chi² = 20.7, p < 0.001) and at the patella (Chi² = 27.6, p < 0.001). We showed a significant difference in the median power frequency of the patella between all movements (Chi² = 17.8, p < 0.5).

INTERPRETATION

Overall, the larger the supposed knee joint loading was, the louder was the recorded knee crepitus. Consequently, vibroarthrographically assessed knee joint sounds can differ across knee joint loading conditions.

Effects of Immobilization and Re-Mobilization on Knee Joint Arthrokinematic Motion Quality

BACKGROUND

Knee immobilization is a common intervention for patients with traumatic injuries. However, it usually leads to biomechanical/morphological disturbances of articular tissues. These changes may contribute to declining kinetic friction-related quality of arthrokinematics; however, this phenomenon has not been analyzed in vivo and remains unrecognized. Thus, the aim of the present study is to investigate the effect of immobilization and subsequent re-mobilization on the quality of arthrokinematics within the patellofemoral joint, analyzed by vibroarthrography (VAG).

METHODS

Thirty-four patients after 6-weeks of knee immobilization and 37 controls were analyzed. The (VAG) signals were collected during knee flexion/extension using an accelerometer. Patients were tested on the first and last day of the 2-week rehabilitation program.

RESULTS

Immobilized knees were characterized by significantly higher values of all VAG parameters when compared to controls (p < 0.001) on the first day. After 2 weeks, the participants in the rehabilitation program that had immobilized knees showed significant improvement in all measurements compared to the baseline condition, p < 0.05. However, patients did not return to normal VAG parameters compared to controls.

CONCLUSION

Immobilization-related changes within the knee cause impairments of arthrokinematic function reflected in VAG signal patterns. The alterations in joint motion after 6 weeks of immobilization may be partially reversible; however, the 2-week physiotherapy program is not sufficient for full recovery.

Dynamic Analysis of Vibration, Muscle Firing, and Force as a Novel Model for Non-Invasive Assessment of Joint Disruption in the knee: A Multiple Case Report

We present a new method for understanding knee pathology through non-invasive techniques. The combination of electromyography (EMG), vibroarthrographic (VAG), and force analysis in proposed to examine the force transfer between unhealthy and healthy knees. A multiple case report is presented to demonstrate the technique and its potential application for future study. The comparison of four individuals’ knee characteristics will be explained using this innovative methodology.

What are the clinical implications of knee crepitus to individuals with knee osteoarthritis? An observational study with data from the Osteoarthritis Initiative

BACKGROUND

Crepitus is a common clinical feature of knee osteoarthritis. However, the importance of crepitus in the overall clinical presentation of individuals with knee osteoarthritis is unknown.

OBJECTIVE(S)

(A) To compare function, pain and quality of life between individuals with knee osteoarthritis with and without crepitus; (B) to compare whether individuals with knee osteoarthritis in both knees, but crepitus in just one, differ in terms of function pain, and knee strength.

METHODS

Setting: Observational study.

PARTICIPANTS

(A) A total of 584 participants with crepitus who had the same Kellgren-Lawrence grade on both knees were matched for gender, body mass index and Kellgren-Lawrence grade to participants without crepitus on both knees. (B) 361 participants with crepitus in only one knee and with the same Kellgren-Lawrence grade classification on both knees were included.

MAIN OUTCOME MEASURE(S)

A - Self-reported function, pain, quality of life, 20-m walk test and chair-stand test. B -Knee extensor and flexor strength, self-reported function and pain.

RESULTS

A - Individuals with crepitus had lower self-reported function, quality of life and higher pain compared to those without crepitus (3-11%; small effect=0.17-0.41, respectively). No difference was found in objective function between groups. B - Self-reported function was lower in the limb with crepitus compared to the limb without crepitus (15%; trivial effect=0.09). No difference was found in pain and knee strength between-groups.

CONCLUSION(S)

Individuals with knee osteoarthritis and knee crepitus have slightly lower self-reported physical function and knee-related quality of life (small or trivial effect). However, the presence of knee crepitus is not associated with objective function or knee strength.

Knee crepitus is not associated with the occurrence of total knee replacement in knee osteoarthritis - a longitudinal study with data from the Osteoarthritis Initiative

OBJECTIVE(S)

To investigate whether the presence of knee crepitus is associated with the occurrence of total knee replacement (TKR), quality of life and deficits in physical function at long-term.

METHODS

Setting - This observational study uses longitudinal data (up to 4-year follow-up) from the Osteoarthritis Initiative (OAI). Participants - 4566 participants. Main Outcome Measure(s) - Logistic regression models were used to test if baseline knee crepitus is associated with the occurrence of TKR. Linear mixed models with adjustment for confounding variables (age, gender, BMI and Kellgren-Lawrence grade) were used to test the association between baseline knee crepitus and longitudinal changes in the pain, self-reported physical function, quality of life and performance-based function.

RESULTS

The presence of knee crepitus at baseline does not predict the occurrence of TKR at 36 months (p=0.58 and 0.67 for right and left knees, respectively). The crepitus group presented a slightly knee extension strength decline from baseline to 48 months (p=0.03 for the right and 0.01 for the left knee; between group difference=2% for both right [95%CI=-0.12; -0.01] and left knees [95%CI=-0.13; -0.02]).

CONCLUSION

The presence of knee crepitus is not associated with the occurrence of TKR in the following three years. Knee crepitus is associated with slightly declines in knee extension strength, but this does not seem to affect physical function and quality of life at long-term.

Implications of knee crepitus to the overall clinical presentation of women with and without patellofemoral pain

OBJECTIVES

Compare anthropometric characteristics, function, kinesiophobia, catastrophism and knee extensor strength between women (i) with PFP and crepitus (PFP_crepitus); (ii) with PFP and no crepitus (PFP_NOcrepitus); (iii) without PFP and crepitus (Pain-free_crepitus); and (iv) without PFP and no crepitus (Pain-free_NOcrepitus).

DESIGN

Cross-sectional.

SETTING

Laboratory study.

PARTICIPANTS

65 women with PFP and 51 pain-free women.

MAIN OUTCOME MEASURES

Objective assessment of knee crepitus, forward step-down and single leg hop tests; knee extensor strength tests; and subjective ratings of function, kinesiophobia, pain catastrophising and knee stiffness.

RESULTS

Crepitus was more common in women with PFP (50.7%) compared to those without (33.3%) (χ₍₁₎²=4.17;p=0.031). PFP_crepitus and PFP_NOcrepitus groups had lower self-reported function; and higher kinesiophobia, catastrophism and knee stiffness compared to Pain-free_crepitus and Pain-free_NOcrepitus groups (p < 0.001). PFP_crepitus, PFP_NOcrepitus and Pain-free_crepitus groups had lower functional performance compared to the Pain-free_NOcrepitus group (p < 0.040). PFP_crepitus and PFP_NOcrepitus groups had lower isometric, concentric and eccentric knee extensor strength compared to the Pain-free_NOcrepitus group (p < 0.041), but not the pain-free_crepitus group. PFP_crepitus presented higher BMI than other groups (p = 0.001).

CONCLUSION

Kinesiophobia, catastrophism, knee stiffness, strength and physical function are all impaired in women with PFP, regardless of crepitus. In pain-free women, crepitus was associated with poorer objective function.