Changes in knee biomechanics after a hip-abductor strengthening protocol for runners with patellofemoral pain syndrome

Context:

Very few authors have investigated the relationship between hip-abductor muscle strength and frontal-plane knee mechanics during running.

Objective:

To investigate this relationship using a 3-week hip-abductor muscle-strengthening program to identify changes in strength, pain, and biomechanics in runners with patellofemoral pain syndrome (PFPS).

Design:

Cohort study.

Setting:

University-based clinical research laboratory.

Patients or Other Participants:

Fifteen individuals (5 men, 10 women) with PFPS and 10 individuals without PFPS (4 men, 6 women) participated.

Intervention(s):

The patients with PFPS completed a 3-week hip-abductor strengthening protocol; control participants did not.

Main Outcome Measure(s):

The dependent variables of interest were maximal isometric hip-abductor muscle strength, 2-dimensional peak knee genu valgum angle, and stride-to-stride knee-joint variability. All measures were recorded at baseline and 3 weeks later. Between-groups differences were compared using repeated-measures analyses of variance.

Results:

At baseline, the PFPS group exhibited reduced strength, no difference in peak genu valgum angle, and increased stride-to-stride knee-joint variability compared with the control group. After the 3-week protocol, the PFPS group demonstrated increased strength, less pain, no change in peak genu valgum angle, and reduced stride-to-stride knee-joint variability compared with baseline.

Conclusions:

A 3-week hip-abductor muscle-strengthening protocol was effective in increasing muscle strength and decreasing pain and stride-to-stride knee-joint variability in individuals with PFPS. However, concomitant changes in peak knee genu valgum angle were not observed.     

Muscle strength and exercise intensity adaptation to resistance training in older women with knee osteoarthritis and total knee arthroplasty

OBJECTIVES:

To analyze muscle strength and exercise intensity adaptation to resistance training in older women with knee osteoarthritis and total knee arthroplasty.

METHODS:

Twenty-three community-dwelling women were divided into the following groups: older, with knee osteoarthritis and total knee arthroplasty in the contralateral limb (OKG; N = 7); older, without symptomatic osteoarthritis (OG; N = 8); and young and healthy (YG; N = 8). Muscle strength (1-repetition maximum strength test) and exercise intensity progression (workload increases of 5%–10% were made whenever adaptation occurred) were compared before and after 13 weeks of a twice-weekly progressive resistance-training program.

RESULTS:

At baseline, OKG subjects displayed lower muscle strength than those in both the OG and YG. Among OKG subjects, baseline muscle strength was lower in the osteoarthritic leg than in the total arthroplasty leg. Muscle strength improved significantly during follow-up in all groups; however, greater increases were observed in the osteoarthritic leg than in the total knee arthroplasty leg in OKG subjects. Greater increases were also seen in the osteoarthritic leg of OKG than in OG and YG. The greater muscle strength increase in the osteoarthritic leg reduced the interleg difference in muscle strength in OKG subjects, and resulted in similar posttraining muscle strength between OKG and OG in two of the three exercises analyzed. Greater exercise intensity progression was also observed in OKG subjects than in both OG and YG subjects.

CONCLUSIONS:

OKG subjects displayed greater relative muscle strength increases (osteoarthritic leg) than subjects in the YG, and greater relative exercise intensity progression than subjects in both OG and YG. These results suggest that resistance training is an effective method to counteract the lower-extremity strength deficits reported in older women with knee osteoarthritis and total knee arthroplasty.     

Comparison of Lower Extremity Kinematics and Hip Muscle Activation During Rehabilitation Tasks Between Sexes

Context:

Closed kinetic chain exercises are an integral part of rehabilitation programs after lower extremity injury. Sex differences in lower extremity kinematics have been reported during landing and cutting; however, less is known about sex differences in movement patterns and activation of the hip musculature during common lower extremity rehabilitation exercises.

Objective:

To determine whether lower extremity kinematics and muscle activation levels differ between sexes during closed kinetic chain rehabilitation exercises.

Design:

Cross-sectional with 1 between-subjects factor (sex) and 1 within-subjects factor (exercise).

Setting:

Research laboratory.

Patients or Other Participants:

Participants included 21 women (age  =  23 ± 5.8 years, height  =  167.6 ± 5.1 cm, mass  =  63.7 ± 5.9 kg) and 21 men (age  =  23 ± 4.0 years, height  =  181.4 ± 7.4 cm, mass  =  85.6 ± 16.5 kg).

Intervention(s):

In 1 testing session, participants performed 3 trials each of single-leg squat, lunge, and step-up-and-over exercises.

Main Outcome Measure(s):

We recorded the peak joint angles (degrees) of knee flexion and valgus and hip flexion, extension, adduction, and external rotation for each exercise. We also recorded the electromyographic activity of the gluteus maximus, rectus femoris, adductor longus, and bilateral gluteus medius muscles for the concentric and eccentric phases of each exercise.

Results:

Peak knee flexion angles were smaller and peak hip extension angles were larger for women than for men across all tasks. Peak hip flexion angles during the single-leg squat were smaller for women than for men. Mean root-mean-square amplitudes for the gluteus maximus and rectus femoris muscles in both the concentric and eccentric phases of the 3 exercises were greater for women than for men.

Conclusions:

Sex differences were observed in sagittal-plane movement patterns during the rehabilitation exercises. Because of the sex differences observed in our study, future researchers need to compare the findings for injured participants by sex to garner a better representation of altered kinematic angles and muscle activation levels due to injury.     

Isokinetic assessment of the hip muscles in patients with osteoarthritis of the knee

OBJECTIVES:

To evaluate the difference in isokinetic strength of hip muscles between patients with knee osteoarthritis (OA) and matched healthy controls, and to establish the correlation between this isokinetic strength and pain and function in patients with knee OA.

METHODS:

25 patients with a diagnosis of unilateral knee OA, 25 patients with bilateral knee OA, and 50 matched controls were evaluated using the visual analog scale for pain, knee Lequesne index, Western Ontario and McMaster Universities questionnaire and an isokinetic test.

RESULTS:

The groups were matched for age, gender and body mass index. The results of the isokinetic test revealed lower peak torque of the hip in patients with OA of the knee than in the control group for all movements studied. Strong correlations were found between the peak torque, visual analog scale and function.

CONCLUSIONS:

Patients with OA of the knee exhibit lower isokinetic strength in the hip muscles than healthy control subjects. Strengthening the muscles surrounding the hip joint may help to decrease pain in people with knee OA. Some correlations between pain/function and peak torque were found.     

Whole-body vibration and the prevention and treatment of delayed-onset muscle soreness

Context:

Numerous recovery strategies have been used in an attempt to minimize the symptoms of delayed-onset muscle soreness (DOMS). Whole-body vibration (WBV) has been suggested as a viable warm-up for athletes. However, scientific evidence to support the protective effects of WBV training (WBVT) on muscle damage is lacking.

Objective:

To investigate the acute effect of WBVT applied before eccentric exercise in the prevention of DOMS.

Design:

Randomized controlled trial.

Setting:

University laboratory.

Patients or Other Participants:

A total of 32 healthy, untrained volunteers were randomly assigned to either the WBVT (n  =  15) or control (n  =  17) group.

Intervention(s):

Volunteers performed 6 sets of 10 maximal isokinetic (60°/s) eccentric contractions of the dominant-limb knee extensors on a dynamometer. In the WBVT group, the training was applied using a vibratory platform (35 Hz, 5 mm peak to peak) with 100° of knee flexion for 60 seconds before eccentric exercise. No vibration was applied in the control group.

Main Outcome Measure(s):

Muscle soreness, thigh circumference, and pressure pain threshold were recorded at baseline and at 1, 2, 3, 4, 7, and 14 days postexercise. Maximal voluntary isometric and isokinetic knee extensor strength were assessed at baseline, immediately after exercise, and at 1, 2, 7, and 14 days postexercise. Serum creatine kinase was measured at baseline and at 1, 2, and 7 days postexercise.

Results:

The WBVT group showed a reduction in DOMS symptoms in the form of less maximal isometric and isokinetic voluntary strength loss, lower creatine kinase levels, and less pressure pain threshold and muscle soreness (P < .05) compared with the control group. However, no effect on thigh circumference was evident (P < .05).

Conclusions:

Administered before eccentric exercise, WBVT may reduce DOMS via muscle function improvement. Further investigation should be undertaken to ascertain the effectiveness of WBVT in attenuating DOMS in athletes.     

Effectiveness of diclofenac versus paracetamol in knee osteoarthritis: a randomised controlled trial in primary care

Background

The effectiveness of diclofenac versus paracetamol in primary care patients with pain caused by knee osteoarthritis is unclear.

Aim

To assess the effectiveness of diclofenac compared with paracetamol over a period of 2, 4, and 12 weeks in patients with knee osteoarthritis.

Design and setting

Randomised controlled trial in general practice.

Method

There were 104 patients included in the study, they were aged ≥45 years consulting their GP with knee pain caused by knee osteoarthritis. Patients were randomly allocated to diclofenac (n = 52) or paracetamol (n = 52) for at least 2 weeks. Primary outcomes were daily knee pain severity, and knee pain and function measured with the Knee Injury and Osteoarthritis Outcome Score (KOOS).

Results

Over a period of 2- and 4-weeks follow-up, no significant difference in daily knee pain was found between the patient groups: estimated differences of 0.5 (95% CI = −0.2 to 1.3) and −0.2 (95% CI = −1.0 to 0.7), respectively. Over the 12-weeks follow-up, no significant differences were found between both groups for KOOS pain: estimated difference of −2.8 (95% CI = −10.7 to 5.1) and KOOS function of −2.7 (−10.6 to 5.0).

Conclusion

Over a period of 2- and 4-weeks follow-up no significant difference in daily measured knee pain severity was found between primary care patients with knee osteoarthritis taking paracetamol or diclofenac. Also, over a period of 12-weeks follow-up no significant differences were found regarding KOOS pain and KOOS function between both groups. Patients more frequently reported minor adverse events after taking diclofenac (64%) than paracetamol (46%).     

Muscle Activation and Movement Patterns During Prone Hip Extension Exercise in Women

Context:

The consistency of muscle activation order during prone hip extension has been debated.

Objective:

To investigate whether women use a consistent and distinguishable muscle activation order when extending the hip while prone and to explore the effects of verbal cues on muscle activation and movement.

Design:

Single-session, repeated-measures design.

Setting:

University laboratory.

Patients or Other Participants:

Eleven healthy women (age  =  27.7 ± 6.2 years [range, 22–37 years]).

Intervention(s):

We tested the participants under 3 conditions: no cues, cues to contract the gluteal muscles, and cues to contract the hamstrings muscles.

Main Outcome Measure(s):

We measured hip and knee angle and electromyographic data from the gluteus maximus, medial hamstrings, and lateral hamstrings while participants performed prone hip extension from 30° of hip flexion to neutral.

Results:

When not given cues, participants used the consistent and distinguishable muscle activation order of medial hamstrings, followed by lateral hamstrings, then gluteus maximus (195.5 ± 74.9, 100.2 ± 70.3, and 11.5 ± 81.9 milliseconds preceding start of movement, respectively). Compared with the no-cues condition, the gluteal-cues condition resulted in nearly simultaneous onset of medial hamstrings, lateral hamstrings, and gluteus maximus (131.3 ± 84.0, 38.8 ± 96.9, and 45.1 ± 93.4 milliseconds, respectively) (P > .059); decreased activation of the medial hamstrings (P < .03) and lateral hamstrings (P < .024) around the initiation of movement; increased activation of gluteus maximus throughout the movement (P < .001); and decreased knee flexion (P  =  .002). Compared with the no-cues condition, the hamstrings-cues condition resulted in decreased activation of the medial hamstrings just after the initiation of movement (P  =  .028) and throughout the movement (P  =  .034) and resulted in decreased knee flexion (P  =  .003).

Conclusions:

Our results support the contention that the muscle activation order during prone hip extension is consistent in healthy women and demonstrates that muscle timing and activation amplitude and movement can be modified with verbal cues. This information is important for clinicians using prone hip extension as either an evaluation tool or a rehabilitation exercise.     

The Hip and Knee Book: developing an active management booklet for hip and knee osteoarthritis

Background

The pain and disability of hip and knee osteoarthritis can be improved by exercise, but the best method of encouraging this is not known.

Aim

To develop an evidence-based booklet for patients with hip or knee osteoarthritis, offering information and advice on maintaining activity.

Design of study

Systematic review of reviews and guidelines, then focus groups.

Setting

Four general practices in North East Wales.

Method

Evidence-based messages were developed from a systematic review, synthesised into patient-centred messages, and then incorporated into a narrative. A draft booklet was examined by three focus groups to improve the phrasing of its messages and discuss its usefulness. The final draft was examined in a fourth focus group.

Results

Six evidence-based guidelines and 54 systematic reviews were identified. The focus groups found the draft booklet to be informative and easy to read. They reported a lack of clarity about the cause of osteoarthritis and were surprised that the pain could improve. The value of exercise and weight loss beliefs was accepted and reinforced, but there was a perceived contradiction about heavy physical work being causative, while moderate exercise was beneficial. There was a fear of dependency on analgesia and misinterpretation of the message on hyaluranon injections. The information on joint replacement empowered patients to discuss referral with their GP. The text was revised to accommodate these issues.

Conclusion

The booklet was readable, credible, and useful to end-users. A randomised controlled trial is planned, to test whether the booklet influences beliefs about osteoarthritis and exercise.     

Contribution of Knee Flexor and Extensor Strength on Sex-Specific Energy Absorption and Torsional Joint Stiffness During Drop Jumping

Context:

Lower extremity injury often occurs during abrupt deceleration when attempting to change the body''s direction. Although sex-specific biomechanics have been implicated in the greater risk of acute knee injury in women than in men, it is unknown if sex differences in thigh strength affect sex-specific energy absorption and torsional joint stiffness patterns.

Objective:

To determine sex differences in energy absorption patterns and joint stiffnesses of the lower extremity during a drop jump and to determine if these sex differences were predicted by knee extensor and flexor strength.

Design:

Cross-sectional study.

Setting:

Laboratory environment.

Patients or Other Participants:

Recreationally active, college-aged students (41 women: age  =  22.1 ± 2.9 years, height  =  1.63 ± 0.07 m, mass  =  59.3 ± 8.0 kg; 40 men: age  =  22.4 ± 2.8 years, height  =  1.77 ± 0.1 m, mass  =  80.9 ± 14.1 kg).

Intervention(s):

Participants performed knee flexor and extensor maximal voluntary isometric contractions followed by double-leg drop-jump landings.

Main Outcome Measure(s):

Lower extremity joint energetics (J × N⁻¹ × m⁻¹) and torsional joint stiffnesses (Nm × N⁻¹ × m⁻¹ × degrees⁻¹) were calculated for the hip, knee, and ankle during the initial landing phase. Body weight was measured in newtons and height was measured in meters. Sex comparisons were made and sex-specific regressions determined if thigh muscle strength (Nm/kg) predicted sagittal-plane landing energetics and stiffnesses.

Results:

Women absorbed 69% more knee energy and had 36% less hip torsional stiffness than men. In women, greater knee extensor strength predicted greater knee energy absorption (R²  =  0.11, P  =  .04), and greater knee flexor strength predicted greater hip torsional stiffness (R²  =  0.12, P  =  .03).

Conclusions:

Sex-specific biomechanics during the deceleration phase of a drop jump revealed that women used a strategy to attempt to decrease system stiffness. Additionally, only female strength values were predictive of landing energetics and stiffnesses. These findings collectively demonstrated that the task may have been more difficult for women, resulting in a different movement strategy among those with different levels of thigh strength to safely complete the task. Future researchers should look at other predictive factors of observed sex differences.     

Two Modes of Weight Training Programs and Patellar Stabilization

Context:

Underconditioned patellar stabilizing muscles could be a predisposing factor for patellar instability.

Objective:

To examine the effect of 2 modes of weight training on the size of the vastus medialis obliquus (VMO), the resting position and passive mobility of the patella, and the strength of the knee extensor muscles.

Design:

Prospective intervention, repeated measures in 3 groups.

Setting:

Orthopaedic and sports sciences research laboratory.

Patients or Other Participants:

48 healthy adults free from back and lower extremity injuries.

Intervention(s):

Participants were randomly assigned to muscle hypertrophy training, muscle strength training, or the control group. Those in the training groups pursued training 3 times per week for 8 weeks.

Main Outcome Measure(s):

Magnetic resonance imaging and ultrasound cross-sectional area of the VMO, patellar tilt angle on magnetic resonance imaging, instrumented passive patellar mobility, and isometric knee extension torque of the dominant leg.

Results:

Participants in both training groups had comparable gains in VMO size, passive patellar stability, and knee extension force, all of which were greater than for the control group (P < .05).

Conclusions:

Both short-term muscle hypertrophy and strength training programs can reinforce the patellar stabilizers in previously untrained volunteers.     

Activity Increase Despite Arthritis (A?DA): phase II randomised controlled trial of an active management booklet for hip and knee osteoarthritis in primary care

Background

The Hip & Knee Book: Helping you cope with osteoarthritis was developed to change disadvantageous beliefs and encourage physical activity in people with hip or knee osteoarthritis.

Aim

To assess the feasibility of conducting a definitive randomised controlled trial (RCT) of this evidence-based booklet in people with hip or knee osteoarthritis.

Design

Phase II feasibility randomised controlled trial (RCT).

Method

Computerised searches of patients'' record databases identified people with osteoarthritis of the hip or knee, who were invited to participate in the RCT comparing the new booklet with a control booklet. Outcomes were measured at baseline, 1 month, and 3 months, and included: beliefs about hip and knee pain, exercise, and fear avoidance; level of physical activity; and health service use.

Results

The trial methods were feasible in terms of recruitment, randomisation, and follow-up, but most participants recruited had longstanding established symptoms. After one and 3 months, there was a small relative improvement in illness, exercise, and fear-avoidance beliefs and physical activity level in The Hip & Knee Book group (n = 59) compared with the control group (n = 60), which provides some proof of principle for using these outcomes in future trials.

Conclusion

This feasibility study provided proof of principle for testing The Hip & Knee Book in a larger definitive RCT.     

Respiratory exercise program for elderly individuals with asthma

INTRODUCTION:

Asthma in older adults is frequently underdiagnosed, as reflected by approximately 60% of asthma deaths occurring in people older than age 65.

OBJECTIVE:

The present study evaluates the effects of a respiratory exercise program tailored for elderly individuals with asthma. We are not aware of any other reports examining breathing exercises in this population.

METHODS:

Fourteen patients concluded the 16-week respiratory exercise program. All the patients were evaluated with regard to lung function, respiratory muscle strength, aerobic capacity, quality of life and clinical presentation.

RESULTS:

After 16 weeks of this open-trial intervention, significant increases in maximum inspiratory pressure and maximum expiratory pressure (27.6% and 20.54%, respectively) were demonstrated. Considerable improvement in quality of life was also observed. The clinical evaluations and daily recorded-symptoms diary also indicated significant improvements and fewer respiratory symptoms. A month after the exercises were discontinued, however, detraining was observed.

DISCUSSION:

In conclusion, a respiratory exercise program increased muscle strength and was associated with a positive effect on patient health and quality of life. Therefore, a respiratory training program could be included in the therapeutic approach in older adults with asthma.     

Segmental stabilization and muscular strengthening in chronic low back pain: a comparative study

OBJECTIVE:

To contrast the efficacy of two exercise programs, segmental stabilization and strengthening of abdominal and trunk muscles, on pain, functional disability, and activation of the transversus abdominis muscle (TrA), in individuals with chronic low back pain.

DESIGN:

Our sample consisted of 30 individuals, randomly assigned to one of two treatment groups: segmental stabilization, where exercises focused on the TrA and lumbar multifidus muscles, and superficial strengthening, where exercises focused on the rectus abdominis, abdominus obliquus internus, abdominus obliquus externus, and erector spinae. Groups were examined to discovere whether the exercises created contrasts regarding pain (visual analogical scale and McGill pain questionnaire), functional disability (Oswestry disability questionnaire), and TrA muscle activation capacity (Pressure Biofeedback Unit  =  PBU). The program lasted 6 weeks, and 30‐minute sessions occurred twice a week. Analysis of variance was used for inter‐ and intra‐group comparisons. The significance level was established at 5%.

RESULTS:

As compared to baseline, both treatments were effective in relieving pain and improving disability (p<0.001). Those in the segmental stabilization group had significant gains for all variables when compared to the ST group (p<0.001), including TrA activation, where relative gains were 48.3% and ‐5.1%, respectively.

CONCLUSION:

Both techniques lessened pain and reduced disability. Segmental stabilization is superior to superficial strengthening for all variables. Superficial strengthening does not improve TrA activation capacity.     

Mixture of Arnebia euchroma and Matricaria chamomilla (Marhame-Mafasel) for pain relief of osteoarthritis of the knee – a two-treatment,two-period crossover trial

Introduction

Osteoarthritis is the most prevalent chronic non-infective joint arthritis. Because of its chronic disease nature, local drugs are preferred due to lower complications. In the present study, the new herbal pomade Marhame-Mafasel for knee osteoarthritis was used in a double-blind crossover trial.The aim of the study was to assess the efficacy and safety of Marhame-Mafasel pomade, which consists of several medical herbs including Arnebia euchroma and Matricaria chamomilla, in osteoarthritis of the knee.

Material and methods

This study was a placebo-controlled double-blind crossover trial. Forty-two patients with pain associated with osteoarthritis of the knee (diagnosed by criteria of the European League against Rheumatism and physical examination) were drawn from patients attending the Clinic of Mostafa-Khomeini Hospital. In this study we assessed efficacy (analgesic effect and improved function) of herbal pomade Marhame-Mafasel, which was used locally in patients with primary osteoarthritis of the knee over three weeks. The instrument of the study was the Western Ontario and McMaster Universities (WOMAC) LK3.1 standard questionnaires.

Results

The participants in each group were 21 patients; 30 (71.4%) were women and 12 (28.6%) of them were men. The participants were between 40 and 76 years old. Six patients had mild arthritis, 15 had moderate arthritis and 21 had severe arthritis. The positive analgesic effect of the herbal pomade Marhame-Mafasel in primary knee osteoarthritis was proven. The herbal joint pomade Marhame-Mafasel had a significantly greater mean change in score compared to the placebo group for osteoarthritis severity (p < 0.05).

Conclusions

Herbal pomade Marhame-Mafasel in comparison to placebo has more effect on reduction of pain of primary knee osteoarthritis.     

Muscle coactivation before and after the impact phase of running following isokinetic fatigue

Context:

The effects of fatigue on impact loading during running are unclear, with some authors reporting increased impact forces and others reporting decreased forces.

Objective:

To examine the effects of isokinetic fatigue on muscle cocontraction ratios about the knee and ankle during running.

Design:

Cross-sectional study.

Setting:

Neuromechanics laboratory.

Patients or Other Participants:

Female middle-distance runners (age  =  21.3 ± 1.93 years) with at least 5 years of training experience.

Intervention(s):

Participants ran on the treadmill at 3.61 m/s before and immediately after the fatigue protocol, which consisted of consecutive, concentric knee extension-flexion at 120°/s until they could no longer produce 30% of the maximum knee-extension moment achieved in the familiarization session for 3 consecutive repetitions.

Main Outcome Measure(s):

Electromyographic (EMG) amplitude of the vastus medialis (VM), biceps femoris (BF), gastrocnemius (GAS), and tibialis anterior (TA) was recorded using surface electrodes. Agonist∶antagonist EMG ratios for the knee (VM∶BF) and ankle (GAS∶TA) were calculated for the preactivation (PR), initial loading response (LR₁), and late loading response (LR₂) phases of running. Hip-, knee-, and ankle-joint angular displacements at initial foot contact were obtained from 3-dimensional kinematic tracings.

Results:

Fatigue did not alter the VM∶BF EMG ratio during the PR phase (P > .05), but it increased the ratio during the LR₁ phase (P < .05). The GAS∶TA EMG ratio increased during the LR₁ phase after fatigue (P < .05) but remained unchanged during the PR and LR₂ phrases (P > .05).

Conclusions:

The increased agonist EMG activation, coupled with reduced antagonist EMG activation after impact, indicates that the acute decrease in muscle strength capacity of the knee extensors and flexors results in altered muscle-activation patterns about the knee and ankle before and after foot impact.     

Defining knee pain trajectories in early symptomatic knee osteoarthritis in primary care: 5-year results from a nationwide prospective cohort study (CHECK)

Background

GPs have high consultation rates for symptoms related to knee osteoarthritis (OA). Many risk factors for symptomatic knee OA progression remain unknown.

Aim

To define distinct knee pain trajectories in individuals with early symptomatic knee OA and determine the risk factors for these pain trajectories.

Design and setting

Data were obtained from the multicentre prospective Cohort Hip and Cohort Knee study in the Netherlands. Participants with knee OA, according to the clinical criteria of the American College of Rheumatology, and a completed 5-year follow-up were included.

Method

Baseline demographic, anamnestic, and physical examination characteristics were assessed. Outcome was annually assessed by the Numeric Rating Scale for pain. Pain trajectories were retrieved by latent class growth analysis. Multinomial logistic regression was used to calculate relative risk ratios.

Results

In total, 705 participants were included. Six distinct pain trajectories were identified with favourable and unfavourable courses. Statistically significant differences were found in baseline characteristics, including body mass index (BMI), symptom severity, and pain coping strategies between the different trajectories. Higher BMI, lower level of education, greater comorbidity, higher activity limitation scores, and joint space tenderness were more often associated with trajectories characterised by more pain at first presentation and pain progression — compared with the reference group with a mild pain trajectory. No association was found for baseline radiographic features.

Conclusion

These results can help differentiate those patients who require more specific monitoring in the management of early symptomatic knee OA from those for whom a ‘wait-and-see’ policy seems justifiable. Radiography provided no additional benefit over clinical diagnosis of early symptomatic knee OA in general practice.