A comprehensive MRI investigation to identify potential biomarkers of Osgood Schlatter disease in adolescents: A cross sectional study comparing Osgood Schlatter disease with controls

BACKGROUND

Osgood-Schlatter disease (OSD) is the most common knee pain complaint among adolescents playing sports. Despite this, there remains controversy over the pathophysiology and whether specific anatomical characteristics are associated with OSD.

PURPOSE

This study aimed to systematically and comprehensively characterize adolescents with OSD using magnetic resonance imaging (MRI) compared to pain-free controls, including both tissue abnormalities that may be associated with OSD, as well as anatomical characteristics. A secondary objective was to identify potential imaging biomarkers associated with pain.

STUDY DESIGN

Cross-sectional study.

METHODS

Adolescents with OSD and controls were recruited from 2020 to 2022. Following a clinical exam, demographics, pain, sports participation, and Tanner stage were collected. Knee MRI was conducted on the participants' most symptomatic knee (OSD) or the dominant leg (controls).

RESULTS

Sixty-seven adolescents (46 with OSD and 30 controls) were included. 80% of participants with OSD had at least one tissue alteration compared to 54% of controls. Compared to controls, OSD had 36.3 (95%CI 4.5 to 289.7) higher odds of bony oedema at the tibial tuberosity, and 32.7 (95%CI 4.1 to 260.6) and 5.3 (95%CI 0.6 to 46.2) higher odds of bony oedema at the  tibial epiphysis and metaphysis respectively. Participants with OSD also had higher odds of fluid/oedema at the patellar tendon (12.3 95%CI 3.3 to 46.6), and superficial infrapatellar bursitis (7.2).  Participants with OSD had a more proximal tendon attachment (mean tibial attachment portion difference, -0.05, 95% CI: -0.1 to 0.0, p = 0.02), tendon thickness (proximal mean difference, -0.09, 95% CI: -0.4 to 0.2, p = 0.04; distal mean difference, -0.6, 95% CI: -0.9 to -0.2, p = 0.01). Those with bony/tendon oedema had 1.8 points (95% CI: 0.3 to 3.2) higher pain on palpation than those without (t = -2.5, df = 26.6, p = 0.019), but there was no difference between these groups in a functional single leg pain provocation.

CONCLUSION

Adolescents with OSD present with tissue and structural abnormalities on MRI that differed from age-matched controls. The majority had findings in the patellar tendon and bone, which often co-occurred. However, a small proportion of OSD also presents without alterations. It appears these findings may be associated with clinical OSD-related pain on palpation of the tibial tuberosity.

CLINICAL RELEVANCE

Our highlight the pathophysiology on imaging, which has implications for understanding the mechanism and treatment of OSD.

How do we explain painful non-traumatic knee conditions to adolescents? A multiple-method study to develop credible explanations

BACKGROUND

Perceived diagnostic uncertainty can leave adolescents confused about their condition and impede their ability to understand "what's wrong with me". Our aim is to develop credible explanations about the condition for adolescents suffering from non-traumatic knee pain.

METHODS

This multiple-method study integrated findings from two systematic literature searches of qualitative and quantitative studies, an Argumentative Delphi with international experts (n = 16) and think-aloud interviews with adolescents (n = 16). Experts provided feedback with arguments on how to communicate credible explanations to meet adolescents' needs; we analysed feedback using thematic analysis. The explanations were tailored based on the adolescent end-users' input.

RESULTS

We screened 3239 titles/abstracts and included 16 papers exploring diagnostic uncertainty from adolescents' and parents' perspectives. Five themes were generated: (1) understanding causes and contributors to the pain experience, (2) feeling stigmatized for having an invisible condition, (3) having a name for pain, (4) controllability of pain, and (5) worried about something being missed. The Argumentative Delphi identified the following themes: (1) multidimensional perspective, (2) tailored to adolescents, (3) validation and reassurance, and (4) careful wording. Merging findings from the systematic search and the Delphi developed three essential domains to address in credible explanations: "What is non-traumatic knee pain and what does it mean?", "What is causing my knee pain?" and "How do I manage my knee pain?"

CONCLUSIONS

Six credible explanations for the six most common diagnoses of non-traumatic knee pain were developed. We identified three domains to consider when tailoring credible explanations to adolescents experiencing non-traumatic knee pain.

SIGNIFICANCE

This study provides credible explanations for the six most common diagnoses of non-traumatic knee pain. Additionally, we identified three key domains that may need to be addressed to reduce diagnostic uncertainty in adolescents suffering from pain complaints. Based on our findings, we believe that clinicians will benefit from exploring adolescents' own perceptions of why they experience pain and perceived management strategies, as this information might capture important clinical information when managing these young individuals.

Patient-centered management strategy for concurrent musculoskeletal complaints in elbows, shoulders, and neck after an isolated hand/forearm complaint: A prospective interventional study

The aim was to evaluate patient-reported outcomes before and after a patient-centered management strategy targeting concurrent proximal musculoskeletal complaints (MSCs) in patients with an isolated hand/forearm complaint. A prospective interventional study included 66 patients. Intervention targeting concurrent MSCs was implemented as a patient-centered add-on to standard treatment for primary hand/forearm complaints. The patient-centered management strategy included patient education, individualized exercises, and manual therapy. Patient-reported outcome measures and pain questionnaires regarding the location, frequency, and intensity of pain in hands, elbows, shoulders, and neck were collected at baseline, after the last session of the patient-centered management strategy, and at 3-month follow-up. There were significant improvements in all patient-reported outcomes between baseline and follow-up. DASH scores improved significantly, by 17-29 points on the 3 subscales. There was a significant improvement of 6 points in PCS, 2 points in HADS, and 0.051 points in EQ-5D index. Median pain intensity on NRS decreased from 6 (4-8) to 5 (2.5-7) in hands, 3 (0-6) to 0 (0-3) in elbows, 5 (2-7) to 2.5 (0-5) in shoulders, and 3 (0-6) to 2 (0-3) in the neck, between baseline and discharge. Patients reporting concurrent MSCs in the elbow, shoulder, and neck after an isolated hand/forearm complaint may benefit from patient-centered management comprising patient education, individualized exercises, and manual therapy targeting pain and functional deficits in the upper-limb and neck. LEVEL OF EVIDENCE: IV.

Knee-extensor strength, symptoms, and need for surgery after two, four, or six exercise sessions/week using a home-based one-exercise program: a randomized dose-response trial of knee-extensor resistance exercise in patients eligible for knee replacement (the QUADX-1 trial)

OBJECTIVE

To investigate firstly the efficacy of three different dosages of one home-based, knee-extensor resistance exercise on knee-extensor strength in patients eligible for knee replacement, and secondly, the influence of exercise on symptoms, physical function and decision on surgery.

METHOD

One-hundred and forty patients eligible for knee replacement were randomized to three groups: 2, 4 or 6 home-based knee-extensor resistance exercise-sessions per week (group 2, 4 and 6 respectively) for 12 weeks.

PRIMARY OUTCOME

isometric knee-extensor strength.

SECONDARY OUTCOMES

Oxford Knee Score, Knee injury and Osteoarthritis Outcome Score, average knee pain last week (0-10 numeric rating scale), 6-min walk test, stair climbing test, exercise adherence and "need for surgery".

RESULTS

Primary analysis: Intention-to-treat analysis of 140 patients did not find statistically significant differences between the groups from baseline to after 12 weeks of exercise in isometric knee-extensor strength: Group 2 vs 4 (0.003 Nm/kg (0.2%) [95% CI -0.15 to 0.15], P = 0.965) and group 4 vs 6 (-0.04 Nm/kg (-2.7%) [95% CI -0.15 to 0.12], P = 0.628). Secondary analysis: Intention-to-treat analyses showed statistically significant differences between the two and six sessions/week groups in favor of the two sessions/week group for Oxford Knee Score: 4.8 OKS points (15.2%) [1.3 to 8.3], P = 0.008) and avg. knee pain last week (NRS 0-10): -1.3 NRS points (-19.5%) [-2.3 to -0.2], P = 0.018. After the 12-week exercise intervention, data were available for 117 patients (N = 39/group): 38 (32.5%) patients wanted surgery and 79 (67.5%) postponed surgery. This was independent of exercise dosage.

CONCLUSION

In patients eligible for knee-replacement we found no between-group differences in isometric knee extensor strength after 2, 4 and 6 knee-extensor resistance exercise sessions per week. We saw no indication of an exercise dose-response relationship for isometric knee-extensor strength and only clinically irrelevant within group changes. For some secondary outcome (e.g., KOOS subscales) we found clinically relevant within group changes, which could help explain why only one in three patients decided to have surgery after the simple home-based exercise intervention.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02931058. Preprint: https://doi.org/10.1101/2021.04.07.21254965.

The relationship between prescribed pre-operative knee-extensor exercise dosage and effect on knee-extensor strength prior to and following total knee arthroplasty: a systematic review and meta-regression analysis of randomized controlled trials

OBJECTIVE

The aim of this systematic review was to evaluate the relationship between prescribed knee-extensor strength exercise dosage in pre-operative exercise intervention and the effect on knee-extensor muscle strength prior to and following TKA. Additional meta-analyses report the effect of pre-habilitation on outcomes prior to and following TKA.

DESIGN

A systematic literature search was performed including RCT's evaluating the effect of pre-operative exercise prior to and following TKA. Meta-regression analysis was performed to evaluate the dose-response relationship between prescribed exercise dose and the pooled effect, measured as standardized mean difference (SMD). The prescribed exercise dose was quantified using a formula accounting for as many exercise descriptors as possible. Risk of bias in the included trials was assessed using the Cochrane Risk of Bias Tool.

RESULTS

Twelve trials with 616 patients were included. Meta-regression analysis showed no relationship between prescribed pre-operative knee-extensor exercise dosage and change in knee-extensor strength neither prior to (slope 0.0005 [95%CI -0.007 to 0.008]) or 3 months following TKA (slope 0.0014 [95%CI -0.006 to 0.009]). Prior to TKA, a moderate effect favoring pre-operative exercise for increase in knee-extensor strength was found (SMD 0.50 [95%CI 0.12 to 0.88]), but not at 3 months following TKA (SMD -0.01 [95%CI -0.45 to 0.43]). Risk of bias was generally assessed as unclear.

CONCLUSION

Meta-regression analysis of existing trials suggests no relationship between the prescribed pre-operative knee-extensor exercise dosage and the change in knee-extensor strength observed prior to and following TKA. Pre-operative exercise including knee-extensor muscle strength exercise increased knee-extensor strength moderately prior to but not 3 months following TKA.

PROTOCOL REGISTRATION

PROSPERO ID (CRD42018076308) (http://www.crd.york.ac.uk/PROSPERO/).

Acute sensory and motor response to 45-s heavy isometric holds for the plantar flexors in patients with Achilles tendinopathy

PURPOSE

The purpose of this study was to explore the immediate effects of heavy isometric plantar flexor exercise on sensory output (pain during a functional task and mechanical pain sensitivity) and motor output (plantar flexor torque) in individuals with Achilles tendinopathy.

METHODS

Sixteen subjects with Achilles tendinopathy participated in the study, mean (SD) age 48.6 (8.9) years and Victorian institute assessment-Achilles (VISA-A) score 61.3 (23.0). Sensory testing assessing pain during a functional task, mechanical pain sensitivity and motor output, and plantar flexor peak torque was completed prior to the intervention. All subjects completed a 45-s heavy isometric plantar flexor contraction and were then re-tested using the same sensory and motor tests. Motor output was assessed using isokinetic dynamometry at speeds previously identified as of interest in subjects with Achilles tendinopathy.

RESULTS

Only 9 of the 16 subjects experienced pain during a functional task, self-reported pain was 4.2 (1.9) numerical rating scale (NRS) pre-intervention and 4.9 (3.2) NRS postintervention (n.s.). Mechanical pressure sensitivity was 446.5 (± 248.5) g/mm² pre-intervention and 411.8 (± 211.8) g/mm² post-intervention (n.s.). Mean concentric plantar flexor torque at 90 and 225°/s was 47.1 (14.5) and 33.6 (11.6) Nm, respectively, pre-intervention and 53.0 (18.5) and 33.4 (6.6) Nm post-intervention (p = 0.039 and n.s.). Eccentric torque at 90°/s was 98.5 (34.2) Nm preintervention versus 106.0 (41.4) Nm post-intervention (n.s.).

CONCLUSION

In this exploratory study, patients with Achilles tendinopathy had a varied sensory and motor output response to heavy isometric contractions. Using the recommended approach of heavy 45-s isometric contractions did not offer a meaningful acute benefit for sensory or motor output for subjects with Achilles tendinopathy. Based on this study, heavy 45-s isometric contractions cannot be recommended for immediate pain relief or improved motor output for patients with Achilles tendinopathy.

LEVEL OF EVIDENCE

IV, prospective cohort study.

Patellar fractures are associated with an increased risk of total knee arthroplasty: A Matched Cohort Study of 6096 Patellar Fractures with a mean follow-up of 14.3 Years

AIMS

The aim of this study was to investigate the incidence of knee arthroplasty and arthroscopy following patellar fractures, and to compare this with an age- and gender-matched group without a prior patellar fracture.

PATIENTS AND METHODS

A national matched cohort study based on the Danish National Patient Register including all citizens of Denmark (approximately 5.3 million) was undertaken. A total of 6096 patients who sustained a patellar fracture in Denmark between 1 January 1996 and 31 December 2000 were included. The median age of these patients was 50.6 years (interquartile range (IQR) 28.5 to 68.9); 49.1% were women. Patients were followed-up until 31 December 2015, with regard to treatment with knee arthroplasty and/or knee arthroscopy.

RESULTS

Patients with a patellar fracture had an increased risk of knee arthroplasty (hazard ratio (HR) 1.83, 95% confidence interval (CI) 1.57 to 2.13) compared with citizens without a patellar fracture, and the effect was strongest during the first five years (HR 3.02, 95% CI 2.26 to 4.03). Patients with a patellar fracture also had a higher risk of knee arthroscopy (HR 3.94, 95% CI 3.49 to 4.46), and the effect was highest during the first five years after the fracture (HR 7.40, 95% CI 6.32 to 8.66).

CONCLUSION

Patellar fractures are associated with an increased risk of knee arthroplasty and knee arthroscopy. The consequences of a patellar fracture may be more severe than previously considered, and patients must expect a lifelong increased risk of knee arthroplasty. Cite this article: Bone Joint J 2018;100-B:1477-81.

Total knee replacement and non-surgical treatment of knee osteoarthritis: 2-year outcome from two parallel randomized controlled trials

OBJECTIVES

To compare 2-year outcomes of total knee replacement (TKR) followed by non-surgical treatment to that of non-surgical treatment alone and outcomes of the same non-surgical treatment to that of written advice.

DESIGN

In two randomized trials, 200 (mean age 66) adults with moderate to severe knee osteoarthritis (OA), 100 eligible for TKR and 100 not eligible for TKR, were randomized to TKR followed by non-surgical treatment, non-surgical treatment alone, or written advice. Non-surgical treatment consisted of 12 weeks of supervised exercise, education, dietary advice, use of insoles, and pain medication. The primary outcome was the mean score of the Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales, covering pain, symptoms, activities of daily living (ADL), and quality of life (QOL).

RESULTS

Patients randomized to TKR had greater improvements than patients randomized to non-surgical treatment alone (difference of 18.3 points (95% CI; 11.3 to 25.3)), who in turn improved more than patients randomized to written advice (difference of 7.0 points (95% CI; 0.4 to 13.5)). Among patients eligible for TKR, 16 (32%) from the non-surgical group underwent TKR during 2 years and among those initially ineligible, seven patients (14%) from the non-surgical group and ten (20%) from the written advice group underwent TKR.

CONCLUSIONS

TKR followed by non-surgical treatment is more effective on pain and function than non-surgical treatment alone, which in turn is more effective than written advice. Two out of three patients with moderate to severe knee OA eligible for TKR delayed surgery for at least 2 years following non-surgical treatment.

TRIAL REGISTRATION

ClinicalTrials.gov numbers NCT01410409 and NCT01535001.

Distribution and symmetrical patellofemoral pain patterns as revealed by high-resolution 3D body mapping: a cross-sectional study

Background

Detailed pain mapping of extent and distribution in individuals with patellofemoral pain (PFP) within and around a complex structure such as the knee has yet to be explored.

Methods

Perceptions of on-going pain from adolescents and young adults (N = 35) with long-standing (>10 months) PFP were collected on high-resolution 3D digital body-schema of the knees. Location, area of pain, pain intensity, laterality, worse side of knee pain, symptom duration, and symmetry in bilateral knee pain were recorded. A threshold for naturally occurring variations in symmetrical knee pain drawings were collected from 18 healthy controls and used in combination with the development a symmetry index (0–1) to create a fuzzy rule for classifying symmetrical and non-symmetrical PFP patterns as compared to a PFP expert. The symmetry index was computed and tested using a correlation coefficient alone or in combination with the Jaccard index and the true and false positive rates (TPR and FPR, respectively) determined.

Results

The peripatellar region was the common report of pain location however, novel and nonconforming PFP patterns were identified and the majority of individuals (22 of 27) with bilateral PFP expressed highly-symmetric mirror-image pain. Individuals with symptom duration of 5 years or more had a greater area of pain, compared to those with symptoms for less than 5 years. The total area of pain was correlated to symptom duration for those with extended symptoms durations and a progression towards an “O” shaped pattern emerged. A TPR of 100% for identifying symmetrical knee pain patterns was found however the expert PFP tended to be stricter, as reflected in FPR of 20%.

Conclusions

A high proportion of PFP patterns or symptoms occur in mirrored locations and are exceptionally symmetrical, and long duration of symptoms appear to converge to an ‘O’ shape. Classifying symmetrical pain patterns is subjective however simple fuzzy rules and correlations can be used to increase objectivity. This study highlights a gap in knowledge of PFP symptom presentation, reveals what may be a natural progression of symptoms, and provides valuable clinical insight for both pain management and treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-017-1521-5) contains supplementary material, which is available to authorized users.

Can we predict the outcome for people with patellofemoral pain? A systematic review on prognostic factors and treatment effect modifiers

BACKGROUND

Patellofemoral pain (PFP) is a multifactorial and often persistent knee condition. One strategy to enhance patient outcomes is using clinically assessable patient characteristics to predict the outcome and match a specific treatment to an individual.

AIM

A systematic review was conducted to determine which baseline patient characteristics were (1) associated with patient outcome (prognosis); or (2) modified patient outcome from a specific treatment (treatment effect modifiers).

METHODS

6 electronic databases were searched (July 2016) for studies evaluating the association between those with PFP, their characteristics and outcome. All studies were appraised using the Epidemiological Appraisal Instrument. Studies that aimed to identify treatment effect modifiers underwent a checklist for methodological quality.

RESULTS

The 24 included studies evaluated 180 participant characteristics. 12 studies investigated prognosis, and 12 studies investigated potential treatment effect modifiers. Important methodological limitations were identified. Some prognostic studies used a retrospective design. Studies aiming to identify treatment effect modifiers often analysed too many variables for the limiting sample size and typically failed to use a control or comparator treatment group. 16 factors were reported to be associated with a poor outcome, with longer duration of symptoms the most reported (>4 months). Preliminary evidence suggests increased midfoot mobility may predict those who have a successful outcome to foot orthoses.

CONCLUSIONS

Current evidence can identify those with increased risk of a poor outcome, but methodological limitations make it difficult to predict the outcome after one specific treatment compared with another. Adequately designed randomised trials are needed to identify treatment effect modifiers.

The STAP-study: The (cost) effectiveness of custom made orthotic insoles in the treatment for plantar fasciopathy in general practice and sports medicine: design of a randomized controlled trial

BACKGROUND

Plantar fasciopathy is a common cause of foot pain, accounting for 11 to 15% of all foot symptoms requiring professional care in adults. Although many patients have complete resolution of symptoms within 12 months, many patients wish to reduce this period as much as possible. Orthotic devices are a frequently applied option of treatment in daily practice, despite a lack of evidence on the effectiveness. Therefore, the objective is to study the (cost)-effectiveness of custom made insoles by a podiatrist, compared to placebo insoles and usual care in patients with plantar fasciopathy in general practice and sports medicine clinics.

METHOD/DESIGN

This study is a multi-center three-armed participant and assessor-blinded randomized controlled trial with 6-months follow-up. Patients with plantar fasciopathy, with a minimum duration of complaints of 2 weeks and aged between 18 and 65, who visit their general practitioner or sport physician are eligible for inclusion. A total of 185 patients will be randomized into three parallel groups. One group will receive usual care by the general practitioner or sports physician alone, one group will be referred to a podiatrist and will receive a custom made insole, and one group will be referred to a podiatrist and will receive a placebo insole. The primary outcome will be the change from baseline to 12 weeks follow-up in pain severity at rest and during activity on a 0-10 numerical rating scale (NRS). Secondary outcomes include foot function (according to the Foot Function Index) at 6, 12 and 26 weeks, recovery (7-point Likert) at 6, 12 and 26 weeks, pain at rest and during activity (NRS) at 6 and 26 weeks and cost-effectiveness of the intervention at 26-weeks. Measurements will take place at baseline and at, 2, 4, 6, 12 and 26 weeks of follow-up.

DISCUSSION

The treatment of plantar fasciopathy is a challenge for health care professionals. Orthotic devices are frequently applied, despite a lack of evidence of the effectiveness on patient reported outcome. The results of this randomized controlled trial will improve the evidence base for treating this troublesome condition in daily practice.

TRIAL REGISTRATION

Dutch Trial Registration: NTR5346 . Date of registration: August 5(th) 2015.

The efficacy of 12 weeks non-surgical treatment for patients not eligible for total knee replacement: a randomized controlled trial with 1-year follow-up

OBJECTIVE

To compare the efficacy of a 12-week non-surgical treatment program with usual care in patients with knee osteoarthritis (OA) not eligible for total knee replacement (TKR).

METHOD

This two-arm parallel group assessor-blinded randomized controlled trial (RCT) included 100 adults from secondary care with knee OA, confirmed by radiography (Kellgren-Lawrence grade ≥1), but not eligible for a TKR. The 12-week non-surgical treatment program consisted of individualized progressed neuromuscular exercise, patient education, insoles, dietary advice and prescription of pain medication if indicated, while usual care comprised two leaflets with information and advice on knee OA and recommended treatments. The primary outcome was the change from baseline to 12 months in the Knee injury and Osteoarthritis Outcome Score (KOOS)4 defined as the average score for the KOOS subscales of pain, symptoms, activities of daily living (ADL), and quality of life (QOL).

RESULTS

91% of the patients completed the 12 months follow-up on the primary outcome. Compared with usual care, patients undergoing the treatment program improved more in KOOS4 (adjusted mean difference (95% CI) of 9.6 (4.4-14.8)) with no serious treatment-related adverse events (AE). The number needed to treat (NNT), defined as the number of patients needed to treat for one person to improve 15% was 7.2. Secondary outcomes supported the primary findings.

CONCLUSION

In patients with mostly moderate to severe knee OA not eligible for TKR, a 12-week individualized, non-surgical treatment program is more efficacious at 12 months compared with usual care and has few treatment-related AE.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT01535001).

Translation and validation of the Danish Foot Function Index (FFI-DK)

The objective of this study was to translate the Foot Function Index (FFI) for use in Danish-speaking patients with foot complaints. The FFI consists of 23 items scored on a numeric rating scale from 0 to 10. The 23 items are grouped into three subscales: pain (nine items), activity limitation (five items), and disability (nine items). The Danish FFI was developed according to the recommended forward/backward translation protocol. The data analysis included reliability [intraclass correlation coefficient (ICC) 2.1] and internal consistency (Cronbach's alpha). Excellent internal consistency was shown for the three subscales: pain (0.99), disability (0.98), and activity limitation (0.98), as for the total score (0.97). The test-retest reliability was excellent: pain subscale: ICC 0.98 [95% confidence interval (CI): 0.97-0.99]; activity limitation subscale: ICC: 0.95 (95% CI: 0.91-0.98); disability subscale: ICC 0.97 (95% CI: 0.95-0.98); total score: ICC: 0.95 (95% CI: 0.91 to 0.98). The mean difference between test and retest was below 1 point and P > 0.08. Bland-Altman plots showed no significant or clinically relevant differences from test to retest in any of the subscales or in the total score. The Danish version of the FFI was found to be valid and reliable and therefore acceptable for use in the Danish population.

Low grading of the severity of knee osteoarthritis pre-operatively is associated with a lower functional level after total knee replacement

The optimal timing of total knee replacement (TKR) in patients with osteoarthritis, in relation to the severity of disease, remains controversial. This prospective study was performed to investigate the effect of the severity of osteoarthritis and other commonly available pre- and post-operative clinical parameters on the clinical outcome in a consecutive series of cemented TKRs. A total of 176 patients who underwent unilateral TKR were included in the study. Their mean age was 68 years (39 to 91), 63 (36%) were male and 131 knees (74%) were classified as grade 4 on the Kellgren–Lawrence osteoarthritis scale. A total of 154 patients (87.5%) returned for clinical review 12 months post-operatively, at which time the outcome was assessed using the Knee Society score.

A low radiological severity of osteoarthritis was not associated with pain 12 months post-operatively. However, it was significantly associated with an inferior level of function (p = 0.007), implying the need for increased focus on all possible reasons for pain in the knee and the forms of conservative treatment which are available for patients with lower radiological severity of osteoarthritis.

Cite this article: Bone Joint J 2014; 96-B:1498–1502.

The influence of time-of-day variation and loading on the aponeurosis plantaris pedis: an ultrasonographic study

AIM

The aim of this paper was to investigate the effect of time-of-day on the thickness of the the aponeurosis plantaris pedis, and to examine the acute effects of high-load strength training and long distance running on the thickness of the aponeurosis plantaris pedis.

METHODS

Proximal aponeurosis plantaris pedis thickness was assessed with a 13-MHz linear-array transducer. In sub-study 1, ten participants (ten aponeurosis') were measured five times during 24 hours. In sub-study 2, ten participants (ten aponeurosis') were measured just before, immediately after and again three hours after 3x12 unilateral heel-rises. In sub-study 3, 11 healthy experienced runners (11 aponeurosis') were measured just before, immediately after and two hours after a 15km run. The average thickness of three scans of each foot was used in the analysis. The data was analysed using repeated measures one-way ANOVA.

RESULTS

The mean thickness of the aponeurosis plantaris pedis' fluctuated significantly during the 24 hours (p=0,02), but it did not change in relation to the high-load strength training (p=0,86) or 15km of running (p = 0,70).

CONCLUSION

High-load strength training and long distance running do not induce changes in the thickness of the aponeurosis plantaris pedis. Time-of-day influences the thickness of the aponeurosis plantaris pedis, but the changes are not larger than measurement uncertainty.

Time-of-day influences postural balance in older adults

BACKGROUND

Postural balance assessments are performed in both clinical and basic research settings on a daily basis. During a 24-h time span our physiology and physical performance undergo radical changes as we are influenced by the circadian rhythm. The time-of-day interaction on postural balance is unknown in older adults. The aim of this study was to investigate the time-of-day effect on postural balance in older adults.

METHODS

Center of pressure (CoP) excursion was measured (100 Hz) by force plate analysis in 34 older adults during 30 s of narrow quiet bilateral stance. Measurements were performed around 9a.m., 12.30 p.m. and 4 p.m. on the same day. Postural balance was quantified by velocity-moment, confidence ellipse area, total sway area and total sway length.

RESULTS

An overall significant time-of-day (between 9 a.m. and 4 p.m.) effect was observed for velocity-moment (mm(2)/s) 57 ± 27-65 ± 29 (p = 0.001), confidence ellipse area (mm(2)) 36 ± 16-44 ± 19 (p < 0.001), total sway area (mm(2)) 548 ± 263-627 ± 285 (p = 0.001) and total sway length (mm) 373 ± 120-379 ± 113 (p = 0.037). The variation of postural balance was mostly pronounced from midday (12.30 p.m.) toward the afternoon (4 p.m.) in all sway parameters. Specifically between 12.30 p.m. and 4 p.m. confidence ellipse area increased by 18.5%, total sway area by 17.1%, velocity-moment by 15.8% and total sway length by 4.6%. No differences were observed between 9 a.m. and 12.30 p.m. in any of the sway parameters.

CONCLUSIONS

This study demonstrates that time-of-day influences postural balance in older adults. These findings have important scientific and clinical relevance, as they imply that time-of-day should be a controlled factor when assessing postural balance in older adults.

Non-linear analysis of the structure of variability in midfoot kinematics

INTRODUCTION

Evaluation of structural variability in biological time series through measures such as sample entropy (SaEn) has provided important information in neurology and cardiology. This has contributed to the development of the "loss of complexity hypothesis" where high variability has been described as healthy flexibility and low variability associated with pathology. The purpose of this study was to calculate sample entropy (SaEn) to establish normal values of non-linear variability and to examine which factors are associated with SaEn in midfoot kinematics.

METHOD

Static foot posture was measured using Foot Posture Index. A video sequence analysis system was used to quantify midfoot kinematics during walking in the sagittal plane. SaEn was calculated for navicular drop during stand phase as an expression of the dynamic complexity.

RESULTS

A significant difference was observed between the three major foot types and between genders (p<0.001). Mean SaEn in women were 1.10+/-0.19 (supinated foot posture), 0.96+/-0.17 (neutral foot posture) and 0.77+/-0.16 (pronated foot posture) and 1.25+/-0.24 (supinated foot posture), 1.06+/-0.23 (neutral foot posture) and 0.86+/-0.19 (pronated foot posture) in males. The regression model showed that foot posture and dynamic navicular drop (dND) were both associated with SaEn.

CONCLUSION

This study confirmed that non-linear analysis is of relevance in the interpretation of kinematic data. Pronated foot posture, large navicular drop and women were characterized by low values of non-linear variability. Future studies should investigate if measurements of SaEn are capable of identifying subjects with an increased risk of injury.

Perspectives for clinical measures of dynamic foot function-reference data and methodological considerations

Several studies have investigated if static posture assessments qualify to predict dynamic function of the foot showing diverse outcomes. However, it was suggested that dynamic measures may be better suited to predict foot-related overuse problems. The purpose of this study was to establish the reliability for dynamic measures of longitudinal arch angle (LAA) and navicular height (NH) and to examine to what extent static and dynamic measures thereof are related. Intra-rater reliability of LAA and NH measures was tested on a sample of 17 control subjects. Subsequently, 79 subjects were tested while walking on a treadmill. The ranges and minimum values for LAA and NH during ground contact were identified over 20 consecutive steps. A geometric error model was used to simulate effects of marker placement uncertainty and skin movement artifacts. Results demonstrated the highest reliability for the minimum NH (MinNH), followed by the minimum LAA (MinLAA), the dynamic range of navicular height (DeltaNH) and the range of LAA (DeltaLAA) while all measures were highly reliable. Marker location uncertainty and skin movement artifacts had the smallest effects on measures of NH. The use of an alignment device for marker placement was shown to reduce error ranges for NH measures. Therefore, DeltaNH and MinNH were recommended for functional dynamic foot characterization in the sagittal plane. There is potential for such measures to be a suitable predictor for overuse injuries while being obtainable in clinical settings. Future research needs to include such dynamic but simple foot assessments in large-scale clinical studies.