Pain-free Knees Research Articles

Symptoms and physical findings of early knee osteoarthritis

Background: There is an increasing need on identifying symptoms and physical findings of the early knee osteoarthritis (KOA). The purpose of this study was to clarify clinical manifestation of early KOA detected by ultrasonography (US) and standard radiographs, and to characterize them for early detection of KOA. Methods: A total of 1,090 participants (2,180 knees) recruited at residential health examinations were evaluated by visual analogue scale of pain, the Japanese Knee Osteoarthritis Measure (JKOM) score as a health-related score, knee extension muscle strength, and images (US and radiographs). Among them, 663 knees with Kellgren-Lawrence Grade (KLG) 0 and 1 were divided into four groups; Group A (with no pain and echo-negative OA findings, n=192), Group B (with no pain and echo-positive OA findings, n=284), Group C (with pain and echo-negative OA findings, n=84), and Group D (with pain and echo-positive OA findings, n=103). Results: Group C and D indicated a significant higher JKOM score than Group A and B, especially in terms of disturbance of activities of daily living (ADLs) such as ascending upstairs or descending downstairs, standing up, and squatting. Group B showed significant higher subscales in disturbance of these ADLs than Group A, although Group B has no pain. Maximum knee extension muscle strength in Group C and D were weaker than Group A and B. Group D indicated the weakest knee extension muscle strength among the groups. In women, weak knee extension muscle strength was significantly correlated with pain and echo-positive OA findings. The risk factors of early KOA were woman, high BMI, and weak extension muscle strength. Conclusions: This study showed that symptoms of early KOA might be not only pain but also the disturbance of ADLs such as ascending upstairs or descending downstairs, standing up, and squatting with weak knee extension muscle strength. Pain-free knees with positive US findings, when disturbing these ADLs, might be the pre-stage of early KOA, namely super-early KOA. For not only treatment of the established KOA, but also prevention of proceeding to early KOA, strengthening of the knee extension muscle to maintain these ADLs might be recommended.

Is Pain in One Knee Associated with Isometric Muscle Strength in the Contralateral Limb?: Data From the Osteoarthritis Initiative.

Knee pain and muscle weakness confer risk for knee osteoarthritis incidence and progression. The purpose of this study was to determine whether unilateral knee pain influences contralateral thigh muscle strength. Of 4796 Osteoarthritis Initiative participants, 224 (mean ± SD age, 63.9 ± 8.9 yrs) cases could be matched to a control. Cases were defined as having unilateral knee pain (numerical rating scale, ≥ 4/10; ≥infrequent pain) and one pain-free knee (numerical rating scale, 0-1; ≤infrequent pain; Western Ontario and McMaster Universities Arthritis Index, ≤ 1). Controls were defined as having bilaterally pain-free knees (numerical rating scale, 0-1; ≤infrequent pain; Western Ontario and McMaster Universities Arthritis Index, ≤ 1). Maximal isometric muscle strength (N) was compared between limbs in participants with unilateral pain (cases) as well as between pain-free limbs of cases and controls. Knee extensor/flexor strength in pain-free limbs of the cases was lower than that in bilaterally pain-free controls (-5.5%/-8.4%; P = 0.043/P = 0.022). Within the cases, maximum extensor/flexor strength was significantly lower in the painful limb than in the pain-free limb (-6.3%/4.1%; P < 0.0001/P = 0.015). These results suggest that strength in limbs without knee pain is associated with the pain status of the contralateral knee. The strength difference between unilateral pain-free cases and matched bilateral pain-free controls was similar to that between limbs in persons with unilateral knee pain. Lower strength caused by contralateral knee pain might be centrally mediated.

Validation of the Questionnaire to Identify Knee Symptoms (QuIKS) using Rasch analysis.

BackgroundThe Questionnaire to Identify Knee Symptoms (QuIKS) was recently developed to promote activity by screening for experiences related to early symptoms in people with emergent chronic knee pain problems, such as osteoarthritis (OA) – like knee pain. The main purpose of the current study was to evaluate measurement properties of the QuIKS using Rasch analysis in a sample of people with knee symptoms consistent with symptomatic knee OA.MethodThis study used cross-sectional data. The sample was 200 subjects along the following knee health continuum: pain-free healthy knees (n = 55) from a university community, knee pain with no knee OA diagnosis (n = 111) from a university-affiliated medical clinic, and patients with surgeon-diagnosed symptomatic knee OA awaiting high tibial osteotomy (n = 34) from a sports medicine surgical clinic. The 13-item QuIKS was evaluated for its factor structure, item- and person-fit, item’s category response structure, differential item functioning by sex and obesity status, local item dependency, unidimensionality, and test precision. Subsequently, the QuIKS underwent known-groups analysis and convergent validity with the Knee injury and Osteoarthritis Outcome Score (KOOS).ResultsIn the QuIKS, each item’s category response structure was modified. No differential item functioning was observed. Local item dependency informed the formation of four testlets. This refined QuIKS obtained summary fit to the Rasch measurement model, unidimensionality, reliability (person separation index = 0.82), and interval-level scoring. Subsequently, the Rasch-validated QuIKS (QuIKS-R) demonstrated excellent known-groups validity and good convergent validity with the KOOS (Spearman’s rho = 0.45 to 0.77).ConclusionsThe QuIKS-R provides interval-level quantification of knee symptoms-related experiences in people with knee symptoms consistent with symptomatic knee OA. Its scores might be useful for clinicians for promoting activity in individuals with early symptoms consistent with symptomatic knee OA.Electronic supplementary materialThe online version of this article (doi:10.1186/s12955-015-0358-6) contains supplementary material, which is available to authorized users.

A Sex-Stratified Multivariate Risk Factor Model for Anterior Cruciate Ligament Injury.

Anterior cruciate ligament (ACL) injuries produce significant joint trauma and have been implicated as the inciting event for both short-term and long-term changes within the articular structures of the knee.[1–8] Regardless of whether a patient chooses surgical or nonsurgical treatment, ACL injury is associated with the onset of posttraumatic arthritis.[9] Consequently, recent researchers have focused on understanding the mechanisms and factors that place individuals at increased risk for sustaining this severe injury. However, variations in study designs and methods have led to conflicting reports regarding these relationships. For example, exclusion criteria used for control participants (eg, combining control participants who have a history of knee pain with those who have normal, pain-free knees) and the approaches used to match case and control participants vary widely among studies. In addition, previous authors have obtained data from the affected knees of ACL-injured patients after the injury. This approach does not take into consideration that the ACL injury itself is capable of producing both short-term and long-term changes in knee-joint geometry.[1,5] Furthermore, few investigators have used measurement techniques with established interobserver and intraobserver measurement reliability.[10] Finally, many researchers have evaluated men and women as a combined group. However, in light of the disparities that exist between the sexes in ACL injury rates, knee-joint geometry, anatomical alignment, joint laxity, demographic characteristics, and strength, male and female models of injury risk should be considered separately.[11]

Lower Extremity Isotonic Relationships Among Physically Active Males and Females

Previous research shows strength deficits in muscle groups lead to faulty kinematics that can contribute to knee pain and injury, specifically in females. It is unclear what phase of an isotonic contraction contributes to the strength deficits. PURPOSE: To investigate isotonic relationships in active males and females during knee flexion and extension, hip rotation, and side hip abduction during 3 isotonic sets. METHODS: Eight males (height 62.3±2.3, body wt. 193.8±55.01, BMI 25.6±5.62) and 9 females (height, 60.2±2.89, body wt, 131.4±17.54, BMI 20.46±2.09) ages 18-35 with pain free knees completed isotonic testing of the dominant leg using an Isokinetic Dynamometer. Actions included knee extension/flexion, hip external rotation, and hip abduction using the isokinetic setting at 30°/sec. Two sets of 5 and 1 endurance set of 20 reps at maximum effort were completed. RESULTS: Independent sample T tests indicated males exhibited higher peak torques for all 3 sets. Pearson Correlations indicated positive relationships between body weight, BMI, and isotonic peak torques in both genders (p=.05). During set 3, positive correlations existed between peak torques of height and concentric knee extension (r-0.810, n=9, p<.01), and body weight and concentric hip abduction (r=.935, n=9, P<0.01) in females. In set 3, positive correlations existed between peak torques of males in BMI and concentric hip external rotation (r=0.870, n=8, p<0.01), height and concentric hip external rotation (r=0.852, n=8, p<0.01), body weight and concentric hip external rotation (r=0.921, n=8, p<0.01), BMI and eccentric knee flexion (r=0.934, n=8, p<0.01) and body weight and eccentric knee flexion (r=0.922, n=8, p<0.01). Taller females tended to have greater knee extension strength while heavier females exhibited greater hip abduction strength. For only body weight, females exhibited higher peak torques in external rotation than males. CONCLUSION: The higher the body weight, height, and BMI, the higher the peak torques in both genders; males had overall higher peak torque performances. By investigating an endurance set (set 3), positive correlations were found among genders concentrically and eccentrically. This information can be useful in determining future steps in exercise training to prevent knee related injuries and disorders.

Quantitative relationship of thigh adipose tissue with pain, radiographic status, and progression of knee osteoarthritis: longitudinal findings from the osteoarthritis initiative.

The aim of this study was to explore the relationship of thigh subcutaneous fat (SCF) and intermuscular fat (IMF) content with knee osteoarthritis (KOA) cross-sectionally and longitudinally, using quantitative magnetic resonance imaging. Specifically, we examined relationships with frequent knee pain, various radiographic strata, and structural progression status of KOA. Subjects who showed between-knee discordance of frequent versus no pain (n = 48), osteophyte versus no radiographic KOA (n = 55), and radiographic joint space narrowing versus no joint space narrowing (n = 44) were selected from the Osteoarthritis Initiative. Knees with structural progression of KOA (n = 23) were compared with knees without progression. Axial thigh magnetic resonance images were used to determine IMF and SCF. Differences between knees and between baseline and 2-year follow-up were examined using paired t tests. Women displayed similar amounts of IMF, but twice the SCF of men. Limbs of women with frequently painful knees had statistically significant greater IMF areas (+4.2%; P = 0.05) than contralateral pain-free limbs did. No significant cross-sectional differences were observed between other strata. Men with structural progression appeared to have a greater longitudinal increase in SCF (+13.2%; P < 0.05) than did men without progression (-1.9%), and women with progression appeared to have a greater increase in IMF (+11.6%) than did those without progression (+1.5%). In women, painful knees display greater IMF content than do contralateral pain-free knees. Other between-knee comparisons did not reveal a regional association between radiographic KOA and thigh adipose tissue status. Structural progression of KOA may be associated with greater longitudinal increases in SCF in men and greater increases of IMF in women, compared with nonprogressive controls.

Contralateral knee effect on self-reported knee-specific function and global functional assessment: data from the Osteoarthritis Initiative.

To analyze the effect of contralateral knee pain on sensitivity of patient-reported outcomes and objectively measured functional performance tests in subjects with knee osteoarthritis (OA). Subjects with discordant knee pain status (i.e., 1 knee being painful [≥4 on a numeric pain rating scale (NPRS)], with the contralateral knee being pain free [NPRS 0]) were selected from the Osteoarthritis Initiative and matched to subjects with bilaterally pain-free and painful knees by age, sex, body mass index, and radiographic knee OA. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) physical function score, the global Physical Activity Scale for the Elderly (PASE), and objective functional performance tests were cross-sectionally compared in a matched case-control design. A total of 378 subjects with discordant knee pain status were matched to 359 controls with bilaterally pain-free knees and to 323 controls with bilaterally painful knees. WOMAC scores in pain-free knees of discordant knee pain cases significantly differed compared to scores of bilaterally pain-free knees (P = 0.003). Likewise, scores in painful knees of discordant knee pain cases significantly differed compared to scores of bilaterally painful knees (P < 0.001). PASE levels between these groups were not significantly different (P > 0.68). Functional performance tests differed in subjects with discordant knee pain compared to subjects with bilaterally pain-free knees and when compared to subjects with bilaterally painful knees, with the chair stand test showing the strongest effect size (standardized response mean 0.28 and 0.33, respectively). The WOMAC physical function score, although knee specific, is impacted by the contralateral knee pain status. The repeated chair stand test appears to be the most sensitive assessment in differentiation between groups with different status of knee pain.

Clinical evaluation during the acute exacerbation of knee osteoarthritis: the impact of diagnostic ultrasonography

We aimed to investigate (1) the probable correlation between clinical and ultrasonographic findings in chronic painful primary knee OA patients referred with acute flare-ups and (2) the impact of diagnostic ultrasonography (US) to determine the real source of pain in these patients. We included 100 patients consecutively who were admitted to our outpatient unit with a pain complaint on a single knee with the diagnosis of primary knee OA according to the ACR criteria. The control group consisted of the patients with pain-free knees at least during the last month, who were already included in the study group. The sonographic evaluation of the knee was performed by a physician who was blinded to the clinical evaluation and/or the physical and radiological evaluations. In the present study, sonographic findings were significantly more observed on the painful knees (p < 0.001). The most commonly encountered findings on the symptomatic knees were the suprapatellar effusion (55 %), the baker cyst (25 %), and the pes anserine bursitis. The distribution of the findings on the asymptomatic knees was as follows: 22 %, the suprapatellar effusion and 5 %, the Baker cyst. Effusion was detected in 55 % of the painful knees of our patients with knee OA. This finding was statistically significant compared to the painless knees of the subjects included. The results of our study also showed that there was a significant relation between the Kellgren-Lawrence grading and the frequency of suprapatellar effusion on US examination (p = 0.026). It was concluded that in chronic, primary, painful knee osteoarthritis, US is a valuable diagnostic method in the confirmation of synovitis and/or the inflammatory episode in spite of the absence of obvious clinical parameters. In advanced osteoarthritis, when we consider that the inflammatory episodes are expected findings, the early confirmation of the inflammation on US may be particularly valuable in the clinical setting.

Patients with patellofemoral pain exhibit elevated bone metabolic activity at the patellofemoral joint

Patellofemoral pain is characterized by pain behind the kneecap and is often thought to be due to high stress at the patellofemoral joint. While we cannot measure bone stress in vivo, we can visualize bone metabolic activity using (18) F NaF PET/CT, which may be related to bone stress. Our goals were to use (18) F NaF PET/CT to evaluate whether subjects with patellofemoral pain exhibit elevated bone metabolic activity and to determine whether bone metabolic activity correlates with pain intensity. We examined 20 subjects diagnosed with patellofemoral pain. All subjects received an (18) F NaF PET/CT scan of their knees. Uptake of (18) F NaF in the patella and trochlea was quantified by computing the standardized uptake value and normalizing by the background tracer uptake in bone. We detected increased tracer uptake in 85% of the painful knees examined. We found that the painful knees exhibited increased tracer uptake compared to the pain-free knees of four subjects with unilateral pain (P = 0.0006). We also found a correlation between increasing tracer uptake and increasing pain intensity (r(2) = 0.55; P = 0.0005). The implication of these results is that patellofemoral pain may be related to bone metabolic activity at the patellofemoral joint.

Greater rates of cartilage loss in painful knees than in pain‐free knees after adjustment for radiographic disease stage: Data from the Osteoarthritis Initiative

To investigate whether rates of cartilage loss differ in knees with frequent baseline pain versus those without pain, after adjustment for radiographic osteoarthritis (OA) stage. One knee in each of 718 Osteoarthritis Initiative participants was examined: 310 with calculated Kellgren/Lawrence (K/L) grade 2, 299 with calculated K/L grade 3, and 109 with calculated K/L grade 4. Twelve-month change in (subregional) cartilage thickness was assessed by magnetic resonance imaging. Change in cartilage thickness in the central subregion of the weight-bearing medial femoral condyle and ordered value 1 (OV1) were selected as primary end points. Frequent knee symptoms were defined as pain, aching, or stiffness on most days of at least 1 month during the previous year. The mean 12-month rate of change in cartilage thickness in the central subregion of the medial femoral condyle was -12 μm (standardized response mean [SRM] -0.15) in knees without pain (n = 146), -27 μm (SRM -0.25) in those with infrequent pain (n = 255), and -54 μm (SRM -0.32) in those with frequent pain (n = 317). Rates differed significantly between frequently painful knees and pain-free knees after adjustment for age, sex, body mass index, and calculated K/L grade (P = 0.011, R(2) = 2.6%, partial R(2) for frequent pain = 1.4%). Similar results were found in stratified samples of calculated K/L grade 2/calculated K/L grade 3 knees, and in analyses restricted to knees with consistent pain frequency between baseline and followup. OV1 results showed similar trends but were not significant. Knees with frequent pain display greater rates of medial cartilage loss longitudinally than knees without pain, with or without adjustment or stratification for radiographic disease stage. Enrollment of participants with frequent knee pain in clinical trials can increase the observed rate of structural progression (i.e., cartilage loss) and sensitivity to change.

Bilateral Sleeve Fracture of the Inferior Poles of the Patella in a Healthy Child: Case Report and Review of the Literature

The initial diagnosis of a sleeve fracture of the patella is key to a successful outcome with poor results well documented in the literature from delayed management. Diagnosis is difficult due to the rarity of this injury and thus the low likelihood the admitting junior doctor would think of this injury in their differential. They are very uncommon in incidence and have features on plain radiography that are difficult to interpret unless the surgeon is familiar with the anatomy of the immature patella. Missing the diagnosis can be disastrous for the patient. In this paper we describe the presentation of bilateral sleeve fractures in a healthy child, our initial investigations and subsequent management. We chose to repair with 5 Ethibond via 3 transosseous tunnels, initially reinforced with a circlage wire. On last review the boy maintains stable, pain-free knees with a full range of motion. The authors hope that this case and literature review will provide a valuable teaching aid and so assist in early, accurate diagnosis and cover the management options to achieve a positive outcome.

Prothèse totale de genou Hermès™ conservant les deux ligaments croisés : comparaison avec la version postérostabilisée au recul de huit ans

The purpose of this study was to determine the functional, clinical and radiographic results obtained with total knee arthroplasty (TKA) preserving both cruciate ligaments using the Hermès prosthesis with a fixed plateau. Mid-term results at eight years mean follow-up were compared with the outcome achieved at the same follow-up with posterior-stabilized (PS) Hermès TKA with a fixed bearing. The results of a continuous series of 41 TKA with bicruciate preservation implanted between 1991 and 1994 with and extra-articular distractor were analyzed at one and eight years follow-up using the IKS scores and radiographic findings. A change in the medial femoral and tibial angles greater than 2 degrees was considered to indicate implant loosening. Results were compared with those of a continuous series of TKA with PS knees implanted during the same period without a distractor and with independent bone cuts. The patients and operated knees were not different between the two groups: femoral and tibial implants were cemented in the large majority of knees with press-fit metal-backed patellar implants and comparable postoperative alignment (179 degrees ). The knees with the TKA bicruciate preservation were painful (37.6%) and exhibited limited mobility (106 degrees ) from the first postoperative year, but the function score was good (80.8 points). Four tibial implants exhibited varus displacement greater than 2 degrees (mean 6.5 degrees ) and six femoropatellar changes were noted (five with lateral displacement of the patella on a non-cemented patellar implant). The knees with a posterior-stabilized TKA were almost all pain-free (44.3 points) and exhibited better range of motion (113.8 degrees ). Among the PS designs, there was the same number of tibial loosenings which were favored, as for the bicruciate preservation TKA, by excessive frontal laxity in extension at one year. Femoropatellar modifications appeared to be less common with the posterior PS knees (one event). There was no measurable polyethylene wear. The good clinical and radiological results obtained by Cloutier, who used the same distractor for the same TKA implants with bicruciate preservation, suggest that the less favourable clinical results and the radiographic modifications of the patellofemoral component, which were more frequent in our bicruciate preserved implants, can be explained by an inadequate use of the distractor. By creating greater ligament tension (which we attempted to achieve), the independent bone cuts do not allow perfect respect of the dynamics of the cruciate ligaments compromising the frontal femoropatellar mechanics. The risk of prosthetic loosening is not greater with TKA bicruciate sparing designs than with PS knees when the postoperative frontal laxity and the frontal realignment are satisfactory. They enabled better function but greater operative precision is required to achieve pain-free knees with a good range of motion.

The Effect of Patient Age, Gender, and Tibial Component Fixation on Pain Relief After Cementless Total Knee Arthroplasty

Cementless total knee arthroplasties (TKAs) were prospectively evaluated for pain relief in 1110 knees. The effect of screws in the tibial component, the age of the patients, and the gender of the patients were studied to determine the effect of these parameters on pain relief one and two years postsurgery. The group with screws in the tibial component (Ortholoc II) had a significantly higher percentage of pain-free knees at one year than at two years postsurgery, and the older patients had a significantly higher rate of pain-free knees at one- and two years postsurgery than the younger patients. Older female patients with Ortholoc I TKAs had a significantly higher percentage of pain-free knees than did older male patients at one-year postsurgery, but not at two years. The group with screws in the tibial components (Ortholoc II) had a higher percentage of pain-free knees at one-year postsurgery than did the Ortholoc I knees, but there was no difference between Ortholoc I and II at two-years postsurgery. In the Ortholoc II group, there was also no difference in results among sexes or between patients older and younger than 65 years old. The correlation coefficient was calculated to evaluate the relationship between body weight and the degree of pain after TKA. No significant correlation could be found at one and two years after surgery.