Adults with patellofemoral pain do not exhibit manifestations of peripheral and central sensitization when compared to healthy pain-free age and sex matched controls - An assessor blinded cross-sectional study.

Patellofemoral Pain (PFP) is highly prevalent among adults and adolescents. Localized mechanical hyperalgesia around the knee and tibialis anterior have been observed in people with PFP, but limited knowledge of potential manifestations of central sensitisation exists. The aims of this study were to study conditioned pain modulation (CPM) and wide-spread hyperalgesia in adults with PFP. This assessor-blinded cross-sectional study design compared CPM and mechanical pressure pain thresholds (PPT) between 33 adults (23 females) diagnosed with PFP and 32 age and sex matched pain-free controls. The investigator taking the PPT measurements was blinded to which participants had PFP. PPTs were reliably measured using a Somedic hand-held pressure algometer at three sites: 1) The centre of the patella, 2) the tibialis anterior muscle and 3) a remote site on the lateral epicondyle. For the assessment of CPM, experimental pain was induced to the contralateral hand by immersion into a cold water bath (conditioning stimulus), and assessment of PPTs (the test stimulus) was performed before and immediately after the conditioning stimulation. On average, the CPM paradigm induced a significant increase in PPTs across the three sites (6.3-13.5%, P<0.05), however there was no difference in CPM between young adults with PFP compared to the control group, (F(1,189) = 0.39, P = 0.89). There was no difference in mechanical PPTs between the two groups (F(1,189) = 0.03, P = 0.86). Contrary to our a-priori hypothesis, we found no difference in CPM or PPT between young adults with PFP and age and sex matched pain-free controls.

Comparison between Mother, ActiGraph wGT3X-BT, and a hand tally for measuring steps at various walking speeds under controlled conditions.

INTRODUCTION: Walking is endorsed as health enhancing and is the most common type of physical activity among older adults. Accelerometers are superior to self-reports when measuring steps, however, if they are to be used by clinicians the validity is of great importance. The aim of this study was to investigate the criterion validity of Mother and ActiGraph wGT3X-BT in measuring steps by comparing the devices to a hand tally under controlled conditions in healthy participants. METHODS: Thirty healthy participants were fitted with a belt containing the sensor of Mother (Motion Cookie) and ActiGraph. Participants walked on a treadmill for two minutes at each of the following speeds; 3.2, 4.8, and 6.4 km/h. The treadmill walking was video recorded and actual steps were subsequently determined by using a hand tally. Wilcoxon's signed ranks test was used to determine whether Mother and ActiGraph measured an identical number of steps compared to the hand tally. Intraclass correlation coefficients were calculated to determine the relationship and Root Mean Square error was calculated to investigate the average error between the devices and the hand tally. Percent differences (PD) were calculated for between-instrument agreement (Mother vs. the hand tally and ActiGraph vs. the hand tally) and PDs below 3% were interpreted as acceptable and clinically irrelevant. RESULTS: Mother and ActiGraph under-counted steps significantly compared to the hand tally at all walking speeds (p < 0.001). Mother had a median of total differences of 9.5 steps (IQR = 10) and ActiGraph 59 steps (IQR = 77). Mother had smaller PDs at all speeds especially at 3.2 km/h (2.5% compared to 26.7%). Mother showed excellent ICC values ≥0.88 (0.51-0.96) at all speeds whilst ActiGraph had poor and fair to good ICC values ranging from 0.03 (-0.09-0.21) at a speed of 3.2 km/h to 0.64 (0.16-0.84) at a speed of 6.4 km/h. CONCLUSION: Mother provides valid measures of steps at walking speeds of 3.2, 4.8, and 6.4 km/h with clinically irrelevant deviations compared to a hand tally while ActiGraph only provides valid measurements at 6.4 km/h based on the 3% criterion. These results have significant potential for valid objective measurements of low walking speeds. However, further research should investigate the validity of Mother in patients at even slower walking speeds and in free-living conditions.

Successful conservative treatment of patients with MRI-verified meniscal lesions.

PURPOSE: To follow a prospective cohort of consecutive patients with MRI-verified meniscal lesions to identify pre-treatment prognostic factors for long-term results following arthroscopic or conservative treatment. METHODS: In the course of 1 year, 291 patients with knee pain and clinically suspected of meniscal lesion were referred to the regional orthopaedic division and subjected to MRI and clinical examination by an experienced surgeon. Patients with MRI-verified meniscal lesions were treated according to an arthroscopy restrictive strategy meaning that treatment was initiated by conservative treatment. Arthroscopy was only performed if satisfying pain relief was not obtained. The Lysholm score and Knee Injury and Osteoarthritis Outcome Score (KOOS) were obtained at baseline and after 12-24 months. A multiple linear regression model was used to investigate which pre-treatment prognostic factors were associated with improvement in the KOOS subscale pain from baseline to follow-up. RESULTS: An MRI-verified meniscal lesion was found in 185 patients (64%). Among these, 58% were treated successfully by conservative treatment. A high KOOS subscale pain score at baseline was associated with less improvement from baseline to follow-up. Bucket-handle lesions were associated with larger improvement from baseline to follow-up compared to flap-tear lesions. CONCLUSION: MRI findings and clinical status measured by KOOS subscale pain are prognostic for improvement among patients treated for MRI-verified meniscal lesions. Good results were observed for both operative and conservative treatment. The success rate for conservative treatment was 58%. LEVEL OF EVIDENCE: Prospective cohort study, Level II.

[Treatment of patients with patellofemoral pain syndrome].

Patellofemoral pain (PFP) is common among adolescents and adults. As the long-term prognosis is poor, optimal treatment is the key. The current evidence suggests that treatment should include training of the quadriceps and hip muscles with focus on correct alignment of the lower extremity. A positive short-term effect of foot orthotics is also documented and there is limited evidence of a positive effect of patella taping. There is no evidence for routine knee arthroscopy in the treating of PFP.

Half of 12-15-year-olds with knee pain still have pain after one year.

INTRODUCTION: Adolescent knee pain is considered benign and presumed to disappear without treatment. However, this has never been investigated. The purpose of this study was to 1) compare leisure time sports participation, health-related quality of life (HRQoL) and body mass index between adolescents with and without self-reported knee pain, 2) investigate how many adolescents still have knee pain after one year and 3) identify risk factors for one-year persistence of knee pain. MATERIAL AND METHODS: The design was a prospective cohort study and a nested case-control study. In September 2011, a total of 768 adolescents between 12-15 years of age from schools in the municipality of Aalborg answered a questionnaire on demographics, sports participation, current pain and HRQoL. After one year, adolescents who reported knee pain at first contact were again contacted by telephone and asked if they experienced knee pain. RESULTS: At first contact, 215 adolescents reported knee pain. Adolescents with knee pain had a significantly higher leisure time sports participation level and a lower HRQoL than adolescents without knee pain. 48.8% (n = 80) still reported knee pain after one year. Female gender, taking part in sports more than twice weekly, lower HRQoL and daily knee pain increased the risk of reporting knee pain after one year. CONCLUSION: Adolescents with self-reported knee pain participate in more leisure time sports and have a lower HRQoL than adolescents without knee pain. 50% had persistent long-lasting knee pain, and a higher frequency of leisure time sports participation increased the risk of reporting knee pain after one year. FUNDING: Danish Rheumatism Association, The Association of Danish Physiotherapists Research Fund and The Obel Family Foundation. None of the funders have any role in the study other than to provide funding. TRIAL REGISTRATION: Ethical approval was obtained from the local ethics committee in the North Denmark Region (N-20110020).

Hip and knee strength is not affected in 12-16 year old adolescents with patellofemoral pain--a cross-sectional population-based study.

BACKGROUND: One of the rationales behind using strength training in the treatment of adolescents with Patellofemoral Pain (PFP) is that reduced strength of the lower extremity is a risk factor for PFP and a common deficit. This rationale is based on research conducted on adolescents >15 years of age but has never been investigated among young adolescents with PFP. OBJECTIVES: To compare isometric muscle strength of the lower extremity among adolescents with PFP compared to age- and gender-matched pain-free adolescents. METHODS: In 2011 a population-based cohort (APA2011-cohort) consisting of 768 adolescents aged 12-15 years from 8 local schools was formed. In September 2012, all adolescents who reported knee pain in September 2011 were offered a clinical examination if they still had knee pain. From these, 20 adolescents (16 females) were diagnosed with PFP. Pain-free adolescents from the APA2011-cohort (n = 20) were recruited on random basis as age- and gender-matched pairs. Primary outcome was isometric knee extension strength normalized to body weight (%BW) and blinded towards subject information. Secondary outcomes included knee flexion, hip abduction/adduction and hip internal/external rotation strength. Demographic data included Knee Injury and Osteoarthritis Outcome Score (KOOS) and symptom duration. RESULTS: Adolescents with PFP reported long symptom duration and significantly worse KOOS scores compared to pain-free adolescents. There were no significant differences in isometric knee extension strength (Δ0.3% BW, p = 0.97), isometric knee flexion strength (Δ0.4% BW, p = 0.84) or different measures of hip strength (Δ0.4 to 1.1% BW, p>0.35). CONCLUSION: Young symptomatic adolescents with PFP between 12 and 16 years of age did not have decreased isometric muscle strength of the knee and hip. These results question the rationale of targeting strength deficits in the treatment of adolescents with PFP. However, strength training may still be an effective treatment for those individuals with PFP suffering from strength deficits.