Only Low Patients' Expectations Are Prognostic for Dissatisfaction With Performing Work-Related Knee-Straining Activities After Total Knee Arthroplasty: A Prospective Multicenter Cohort Study.

OBJECTIVE: To investigate whether preoperative expectations regarding performing work-related knee-straining activities were associated with being dissatisfied 6 months after total knee arthroplasty (TKA) among working patients, and, to identify prognostic factors for being dissatisfied with performing these work-related knee-straining activities. DESIGN: Multicenter prospective cohort study. SETTING: Orthopedic surgery departments of 7 hospitals in the Netherlands. PARTICIPANTS: A consecutive sample of 175 working patients who were on the waiting list for TKA (median age 59 years, 53% women) and intended to return to work (N=175). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE(S): Dissatisfaction with performing work-related knee-straining activities 6 months postoperative was measured using the Work Osteoarthritis or joint-Replacement Questionnaire (score range 0-100). The clinically relevant cut-off points for being satisfied and dissatisfied were ≥71 and ≤50, respectively. RESULTS: Thirty-three patients (19%) were dissatisfied with performing work-related knee-straining activities 6 months after TKA. Patients who expected to be dissatisfied preoperative had a 5.1 times higher odds (95% CI 1.7-15.5) of being dissatisfied 6 months postoperatively compared with patients who expected to be satisfied preoperative. Regression analyses revealed that only patients' expectations were prognostic for being dissatisfied 6 months postoperatively rather than age, pain level, or having a knee-straining job. CONCLUSIONS: Two in 10 working patients are dissatisfied with performing work-related knee-straining activities 6 months after TKA. Only preoperative patients' expectations appeared prognostic. Therefore, we should better prepare working patients with low expectations by managing their preoperative expectations and improving their performance of work-related knee-straining activities in rehabilitation.

Comparison of early migration patterns between a ceramic and polyethylene liner in uncemented Trabecular Titanium cups: a 2-year randomized controlled trial of 52 hips using radiostereometric analysis.

BACKGROUND AND PURPOSE: Ceramic liners may reduce early stability of uncemented acetabular components due to higher stiffness. However, the bone ingrowth capacities of porous trabecular titanium might compensate for this effect. This prospective randomized trial quantifies migration patterns of the Delta-TT cup, and compares polyethylene and ceramic liners. PATIENTS AND METHODS: Patients undergoing primary uncemented total hip arthroplasty with the Delta-TT cup and femoral stem with ceramic head were randomized to a polyethylene (n = 25) or ceramic (n = 28) liner. Radiostereometric analysis (RSA) radiographs, patient-reported hip function (HOOS-PS, OHS), and quality of life (EQ5D) were collected at baseline and 1.5, 3, 6, 12, and 24 months postoperatively. Model-based RSA was used to calculate 3D cup translation and rotation, and mixed models were used to compare effects over time between groups. RESULTS: At 2 years follow-up, Delta-TT cups showed similar mean proximal translation of 0.56 mm (95% CI 0.38-0.75) in the ceramic (CE) group and 0.54 mm (0.30-0.77) in the polyethylene (PE) group, with a between group effect of 0.02 mm (-0.20-0.23). Most cup migration occurred in the first 1.5 to 3 months, stabilizing within 6 months. Any between-group effects were ≤ 0.30 mm for translation and ≤ 0.45° for rotation. Improvements in patient-reported hip function and quality of life were similar in both groups. INTERPRETATION: Regardless of liner type, Delta-TT cups showed some initial migration and stabilized within 6 months, which seems promising for long-term fixation in both cup-liner constructs.

Increased Persistent Mid-Thigh Pain After Short-Stem Compared With Wedge-Shaped Straight-Stem Uncemented Total Hip Arthroplasty at Medium-Term Follow-Up: A Randomized Double-Blinded Cross-Sectional Study.

BACKGROUND: Femoral prosthesis design may impact the frequency of mid-thigh pain. We compared current, incidental, and persistent mid-thigh pain between the short-stem, Collum Femoris femur prosthesis, and the wedge shaped straight-stem, Zweymüller femur prosthesis and studied the associations between demographics, radiographic measurements, and mid-thigh pain. METHODS: We contacted patients from a randomized controlled trial who underwent uncemented total hip arthroplasty (THA) for hip osteoarthritis at a mean follow-up of 44 months (range 24-64 months). Patients were specifically assessed for current (during assessment), incidental (any time postoperatively for >1 week) mid-thigh pain, and persistent (any time postoperatively for >2 years) mid-thigh pain. Furthermore, we used regression analysis to study associations between demographics, radiographic measurements, and mid-thigh pain. RESULTS: One hundred forty of 150 patients (93%) responded to our assessment. Mean age at the time of operation was 62 years (±7.0). Current mid-thigh pain occurred in 16 patients (23%) in the Collum Femoris Preserving (CFP) group compared with 10 patients (14%) in the Zweymüller group (P = .192). Incidental mid-thigh pain occurred in 24 patients (34%) in the CFP group compared with 15 patients (21%) in the Zweymüller group (P = .090). Persistent mid-thigh pain was found in 13 patients (19%) in the CFP group compared with five patients (7%) in the Zweymüller group (P = .043). Varus malalignment (odds ratio 1.819 [95% confidence interval 1.034-3.200]) and leg lengthening (odds ratio 1.107 per cm lengthening [95% confidence interval 1.026-1.195]) showed significant associations with mid-thigh pain. CONCLUSIONS: We found more persistent mid-thigh pain after short-stem uncemented THA compared to wedge-shaped straight-stem uncemented THA during medium-term follow-up. Varus malalignment and leg lengthening were associated with mid-thigh pain.

Three Out of Ten Working Patients Expect No Clinical Improvement of Their Ability to Perform Work-Related Knee-Demanding Activities After Total Knee Arthroplasty: A Multicenter Study.

Purpose Three out of ten patients do not return to work after total knee arthroplasty (TKA). Patient expectations are suggested to play a key role. What are patients' expectations regarding the ability to perform work-related knee-demanding activities 6 months after TKA compared to their preoperative status? Methods A multi-center cross-sectional study was performed among 292 working patients listed for TKA. The Work Osteoarthritis or joint-Replacement Questionnaire (WORQ, range 0-100, minimal important difference 13) was used to assess the preoperatively experienced and expected ability to perform work-related knee-demanding activities 6 months postoperatively. Differences between the preoperative and expected WORQ scores were tested and the most difficult knee-demanding work-related activities were described. Results Two hundred thirty-six working patients (81%) completed the questionnaire. Patients' expected WORQ score (Median = 75, IQR 60-86) was significantly (p < 0.01) higher than their preoperative WORQ score (Median = 44, IQR 35-56). A clinical improvement in ability to perform work-related knee-demanding activities was expected by 72% of the patients, while 28% of the patients expected no clinical improvement or even worse ability to perform work-related knee-demanding activities 6 months after TKA. Of the patients, 34% expected severe difficulty in kneeling, 30% in crouching and 17% in clambering 6 months after TKA. Conclusions Most patients have high expectations, especially regarding activities involving deep knee flexion. Remarkably, three out of ten patients expect no clinical improvement or even a worse ability to perform work-related knee-demanding activities 6 months postoperatively compared to their preoperative status. Therefore, addressing patients expectations seems useful in order to assure realistic expectations regarding work activities.

Feedback to Patients About Patient-reported Outcomes Does Not Improve Empowerment or Satisfaction.

BACKGROUND: Although patient-reported outcome measures (PROMs) are helpful to define whether an intervention has improved a patient's status in ways the patient feels are important, they may also serve an empowering educational role; specifically, sharing a patient's scores might help the patient understand his or her progress during treatment. However, whether sharing PROM scores in this way improves the sense of empowerment or satisfaction with the process of care has not been well explored. Also, less is known whether specific demographic factors or coping strategies are associated with empowerment. QUESTIONS/PURPOSES: We asked the following: (1) Does giving patients feedback on their PROM scores improve a patient's sense of empowerment or satisfaction? (2) Do demographic factors, duration of disability, or self-efficacy correlate with patient empowerment? METHODS: In this prospective cohort study, we assigned patients with osteoarthritis of the knee or hip sequentially such that the first 70 patients did not receive the intervention and the next 72 did. Patients enrolled in the control cohort were managed according to standard care, whereas patients enrolled in the intervention cohort completed web-based questionnaires measuring their physical function and pain. After filling out the questionnaires, a printout with the scores was given to the patients providing feedback about their physical function and pain. The primary outcome measure was patient empowerment, as measured by the Patient Activation Measure. Secondary outcomes were patient satisfaction, as measured by an 11-point Likert scale and Patient Doctor Relation Questionnaire. Independent variables were demographic factors and coping, measured by the Pain Self-efficacy Questionnaire. Bivariate and multivariable analyses were performed to determine the influence of the feedback. Although no minimum clinically important differences have been defined for the patient empowerment or satisfaction scales, we believe that differences smaller than 10% are unlikely to be clinically important, even if they are statistically significant. RESULTS: Although the group that received PROM feedback had higher scores for empowerment than the group that did not, the effect size was small and likely not to have been clinically important (2.8 ± 0.85 versus 3.1 ± 0.811; mean difference -0.31; 95% confidence interval, 2.8-3.1; p = 0.037). With the numbers available, there were no differences between the group given PROM feedback and the group that did not receive such feedback in terms of satisfaction scores (8.6 ± 1.4 versus 8.8 ± 1.2; mean difference -0.19; p = 0.39). After controlling for demographic factors such as level of education and duration of complaint, we found that the group that received PROM feedback and who had a higher level of self-efficacy had higher scores for empowerment than the group that did not, although the effect size was small. CONCLUSIONS: PROM feedback did not have a clinically important impact on empowerment or satisfaction. This might indicate that counseling based on PROMs during a single visit may be ineffective. The most important positive finding is that more effective coping strategies are associated with greater patient empowerment. LEVEL OF EVIDENCE: Level II, therapeutic study.

Classification systems for distal radius fractures.

Background and purpose - The reliability of conventional radiography when classifying distal radius fractures (DRF) is fair to moderate. We investigated whether reliability increases when additional computed tomography scans (CT) are used. Patients and methods - In this prospective study, we performed pre- and postreduction posterior-anterior and lateral radiographs of 51 patients presenting with a displaced DRF. The case was included when there was a (questionable) indication for surgical treatment and an additional CT was conducted within 5 days. 4 observers assessed the cases using the Frykman, Fernández, Universal, and AO classification systems. The first 2 assessments were performed using conventional radiography alone; the following 2 assessments were performed with an additional CT. We used the intraclass correlation coefficient (ICC) to evaluate reliability. The CT was used as a reference standard to determine the accuracy. Results - The intraobserver ICC for conventional radiography alone versus radiography and an additional CT was: Frykman 0.57 vs. 0.51; Fernández 0.53 vs. 0.66; Universal 0.57 vs. 0.64; AO 0.59 vs. 0.71. The interobserver ICC was: Frykman: 0.45 vs. 0.28; Fernández: 0.38 vs. 0.44; Universal: 0.32 vs. 0.43; AO: 0.46 vs. 0.40. Interpretation - The intraobserver reliability of the classification systems was fair but improved when an additional CT was used, except for the Frykman classification. The interobserver reliability ranged from poor to fair and did not improve when using an additional CT. Additional CT scanning has implications for the accuracy of scoring the fracture types, especially for simple fracture types.

Arthroscopic Partial Meniscectomy or Conservative Treatment for Nonobstructive Meniscal Tears: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

PURPOSE: To conduct a meta-analysis of randomized controlled trials comparing the outcome of arthroscopic partial meniscectomy (APM) with conservative treatment in adults with nonobstructive meniscal tears and to recommend a treatment of choice. METHODS: We systematically searched the databases of MEDLINE, Excerpta Medica Database, Cochrane, the National Health Service Centre for Reviews and Dissemination, and Physiotherapy Evidence Database from inception to May 2, 2016. Two authors independently searched the literature and selected eligible studies. The meta-analyses used a random-effects model. The primary outcome was physical function, measured by knee-specific patient-reported outcomes. Secondary outcomes included knee pain, activity level, the progression of osteoarthritis, adverse events, general health, and quality of life. RESULTS: We included 6 randomized controlled trials, with a total of 773 patients, of whom 378 were randomized to APM and 395 were randomized to the control treatment. After pooling the data of 5 studies, we found small significant differences in favor of the APM group for physical function at 2 to 3 months (mean difference [MD] = 3.31; 95% confidence interval [CI] = 0.69-5.93; P = .01; I(2) = 0% [Lysholm knee score]), and at 6 months (MD = 3.56; 95% CI = 0.24-6.88; P = .04; I(2) = 0% (Knee injury and Osteoarthritis Outcome Score [KOOS] and Western Ontario and McMaster Universities Osteoarthritis Index); standardized MD = 0.17; 95% CI = 0.01-0.32; P = .03; I(2) = 0% [Lysholm knee score, KOOS, and Western Ontario and McMaster Universities Osteoarthritis Index]). We also found small significant differences for pain at 6 months (MD = 3.56; 95% CI = 0.18-6.95; P = .04; I(2) = 0% [KOOS] and MD = 0.56; 95% CI = 0.28-0.83; P ≤ .0001; I(2) = 0% [visual analog scale and numeric rating scale]). We found no significant differences after 12 and 24 months. CONCLUSIONS: We found small, although statistically significant, favorable results of APM up to 6 months for physical function and pain. However, we found no differences at longer follow-up. LEVEL OF EVIDENCE: Level I, systematic review and meta-analysis of Level I studies.

Can We Measure the Heel Bump? Radiographic Evaluation of Haglund's Deformity.

Haglund's deformity is a symptomatic posterosuperior deformity of the heel. The lateral radiograph of the ankle will show a prominent, large, posterosuperior part of the calcaneus, which can be measured using the Fowler and Philips angle (FPA, the angle between the posterior and plantar surface of the calcaneus) and the calcaneal pitch angle (CPA, the angle between the sole of the foot and the plantar part of the calcaneus). Although these angles are commonly used, these radiographic angle measurements have never shown a relationship with Haglund's deformity. In 78 patients (51% male) with symptomatic Haglund's deformity and a control group of 100 patients (41% male) with no heel complaints, we measured the FPA and CPA on weightbearing lateral radiographs of the foot. Using an unpaired t tests, no significant difference was found between the 2 groups in the FPA (p = .40). We measured a significant difference in the CPA between the Haglund group and the control group (p = .014). Subgroup analysis showed that this difference was mainly found in females (p < .00), with no significant difference seen in the males (p < .48). Females with Haglund's deformity will have a greater CPA than will females without Haglund's deformity. The CPA showed a difference between the Haglund and non-Haglund groups, although mainly in females. Although the evidence from our study is limited, it would be interesting to study the CPA further, because it implicates the verticalization of the calcaneus. This change in position results in extra traction on the Achilles tendon and can eventually cause tendinitis and bursitis. Radiographic measurement should be used as an auxiliary tool. If the calcaneus tends to change position, it would be interesting to understand this process, which could eventually lead to improvement in the treatment of Haglund's deformity.

Similar success rates for single and multiple debridement surgery for acute hip arthroplasty infection.

BACKGROUND: Treatment of an acute total hip arthroplasty (THA) infection aims at control of the infection with retention of the implant by surgical debridement and antibiotic treatment. There is no clear evidence whether a single surgical debridement is sufficient or whether multiple procedures are necessary for optimal treatment. METHODS: From a prospective database of patients with acute THA infection, we retrospectively reviewed 68 patients treated in 2 large teaching hospitals. Hospital S used a protocol in which each patient received a single surgical debridement and only additional surgery if infectious symptoms persisted (group S; n = 33). In hospital M, patients always received multiple surgical debridements (group M; n = 35). Both groups received systemic antibiotic treatment. Removal of the implant or persistent infection at follow-up was considered failure of treatment. Mean follow-up of the patients was 5 (2-11) years. RESULTS: Mean time between implantation and debridement was 19 days. 4 patients in group S were considered failure, as opposed to 10 patients in group M (p = 0.09). 9 patients in group S had additional surgery, which resulted in 3 of the 4 failures. At final follow-up, 30 patients in group S and 33 patients in group M had a good clinical result (p = 0.6). INTERPRETATION: In patients with acute THA infection, a single debridement with only additional surgery on indication appears to be at least as successful for retention of the primary implant and control of infection as a strategy with multiple surgical debridements.

Short-term functional outcome after hip resurfacing surgery.

Hip resurfacing arthroplasty is a popular method for treating late stage osteoarthritis, especially in young and active patients. Most studies presenting short-term follow-up after hip resurfacing present radiographic or dual clinician-patient-related outcome. These kinds of outcomes are influenced by interpretation of the clinician and do not tell us much about functional outcome from the patients perspective. Today, functional outcome is often measured using patient-reported outcome instruments. We used the patient-reported 'Hip Disability and osteoarthritis Outcome Score' questionnaire, which has good measurement properties, to assess short-term functional outcome in 160 patients (mean follow-up of 2.6 years) after hip resurfacing surgery. Furthermore, we focused on pain, range of motion, subjective improvement and complications. The majority (86.9%) of patients was free of pain after surgery and range of motion improved significantly. Subjective improvement was indicated in 95% of the patients. Mean HOOS in 149 patients was 87.5. In total, there were 11 complications (6%), and deep infections contributed the most (3.4%). In general, short-term follow-up after hip resurfacing in this cohort showed good clinical and patient-reported functional outcome. When assessing the results of medical interventions, a good PRO instrument can give reliable and valuable information from the patients perspective.

The importance of addressing heteroscedasticity in the reliability analysis of ratio-scaled variables: an example based on walking energy-cost measurements.

AIM: When analysing the reliability of ratio-scaled variables, such as walking energy cost, variability of the error term often increases with increasing mean values. This phenomenon is called heteroscedasticity, and it makes the analysis of reliability more complicated. This study presents an examination of heteroscedasticity for walking energy cost before analysing the reliability. METHOD: Walking energy cost was collected from 33 children with cerebral palsy (CP), with varying Gross Motor Function Classification System (GMFCS) levels (19 males; 14 females; mean age: 7y 6mo [SD 2y 6mo]; GMFCS levels I [n=16], II [n=7], and III [n=10]). It was assessed by measuring oxygen uptake during 10 minutes of resting and 5 minutes of walking at comfortable speed. Measurements were performed twice, within 4 to 6 weeks. Primary outcomes included gross energy cost, gross non-dimensional energy cost, net energy cost, net non-dimensional energy cost, speed, and non-dimensional speed. Heteroscedasticity was analysed with Bland-Altman plots and Kendall's tau. RESULTS: Visual inspection of the Bland-Altman plots showed heteroscedasticity for gross energy cost, gross non-energy cost, and net energy cost. This was confirmed by Kendall's tau coefficients. Accordingly, data were logarithmically transformed, and reliability was assessed with ratio statistics. For speed, heteroscedasticity was not observed. INTERPRETATION: Variability of gross energy cost, gross non-energy cost, and net energy cost, assessed across different GMFCS levels in children with CP, was proportional to the mean, indicating the presence of heteroscedasticity. This finding emphasizes the importance of always performing a heteroscedasticity examination in reliability studies on energy cost and reporting the reliability statistics accordingly.

Validation of the Dutch version of the Simple Shoulder Test.

BACKGROUND: The Simple Shoulder Test (SST) is an internationally used patient-reported outcome for clinical practice and research purposes. It was developed for measuring functional limitations of the affected shoulder in patients with shoulder dysfunction and contains 12 questions (yes/no). The purpose of this study was to create a Dutch translation of the SST and to assess the reliability and validity. MATERIALS AND METHODS: The SST was translated into Dutch using forward and backward translations. A consecutive cohort of patients with shoulder problems visiting an orthopedic clinic completed the Dutch version of the SST twice within 28 days. In addition, the Dutch validated versions of the Disabilities of the Arm, Shoulder and Hand, Oxford Shoulder Score, and Constant-Murley shoulder assessment were completed for assessing construct validity. RESULTS: One hundred ten patients with a mean age of 39 years (SD, 14 years), 72% male, completed the questionnaires. The internal consistency was high (Cronbach α, 0.78). The test-retest reliability was very good (intraclass correlation coefficient, 0.92) (n = 55). The measurement error expressed in the standard error of measurement was 1.18, and the smallest detectable change was 3.3 on a scale from 0 to 12. The construct validity was supported by expected high correlations between the Dutch version of the SST and the Disabilities of the Arm, Shoulder and Hand (r = -0.74) and between the SST and the Oxford Shoulder Score (r = -0.74) and an expected moderate correlation between the SST and the Constant-Murley shoulder assessment (r = 0.59). CONCLUSION: The Dutch version of the SST seems to be a reliable and valid instrument for evaluating functional limitations in patients with shoulder complaints.

Digital medical history implementation to triage orthopaedic patients during COVID-19: Findings from a rapid cycle, semi-randomised A/B testing quality improvement project.

INTRODUCTION: The COVID-19 pandemic severely impacted musculoskeletal care. To better triage the notable backlog of patients, we assessed whether a digital medical history (DMH), a summary of health information and concerns completed by the patient prior to a clinic visit, could be routinely collected and utilised. METHODS: We analysed 640 patients using a rapid cycle, semi-randomised A/B testing approach. Four rapid cycles of different randomised interventions were conducted across five unique patient groups. Descriptive statistics were used to report DMH completion rates by cycle/patient group and intervention. Multivariable logistic regression was used to determine whether age or anatomic injury location was associated DMH completion. ETHICAL APPROVAL: N/A (Quality Improvement Project) RESULTS: Across all patients, the DMH completion rate was 48% (307/640). Phone calls were time consuming and resource intensive without an increased completion rate. The highest rate of DMH completion was among patients who were referred and called the clinic themselves (78% of patients [63 out of 81 patients]). Across all patients, increasing age (odds ratio [OR]: 0.985 (95% CI: 0.976-0.995), p = 0.002), patients with back concerns (OR: 0.395 (95% CI: 0.234-0.666), p = 0.001), and patients with non-specific/other musculoskeletal concerns (OR: 0.331 (95% CI: 0.176-0.623), p = 0.001) were associated with decreased odds of DMH completion. DISCUSSION AND CONCLUSION: DMHs can be valuable in helping triage orthopaedic patients in resource-strapped settings, times of crisis, or as we transition towards value-based health care delivery. However, further work is needed to continue to increase the completion rate about 50%.

Measuring mobility limitations in children with cerebral palsy: Rasch model fit of a mobility questionnaire, MobQues28.

OBJECTIVE: To develop a Rasch-based version of a mobility questionnaire (MobQues28) for children with cerebral palsy (CP). DESIGN: Cross-sectional study. SETTING: Private physical therapy practices and outpatient departments of hospitals and rehabilitation centers. PARTICIPANTS: Parents of 323 ambulatory children with CP (Gross Motor Function Classification System [GMFCS] level I-IV; aged, 2-13y). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: The mobility questionnaire measures mobility limitations in children with CP by rating the difficulty of executing 47 mobility activities, as reported by the parents. Items for the Rasch-based version were selected based on fit to the Rasch measurement (partial credit) model and invariance of item characteristics across GMFCS level, age group, or sex. RESULTS: Analysis revealed a fitting model when nonambulant and/or 2- and 3-year aged children were excluded (leaving a final sample of n=246) and answering categories were collapsed from 9 to 5. Thirteen items were removed from the questionnaire due to misfit to the model, 5 because of disordered thresholds, and 1 because of invariance across age group. Twenty-eight items out of the original 47 items showed good fit to the model. CONCLUSIONS: The 28-item version of the mobility questionnaire (MobQues28) provides sound measurement properties for measuring mobility limitations in ambulant children with CP, aged 4 to 13 years, and shows promise as an instrument for research purposes.

Reliability of maximal isometric knee strength testing with modified hand-held dynamometry in patients awaiting total knee arthroplasty: useful in research and individual patient settings? A reliability study.

BACKGROUND: Patients undergoing total knee arthroplasty (TKA) often experience strength deficits both pre- and post-operatively. As these deficits may have a direct impact on functional recovery, strength assessment should be performed in this patient population. For these assessments, reliable measurements should be used. This study aimed to determine the inter- and intrarater reliability of hand-held dynamometry (HHD) in measuring isometric knee strength in patients awaiting TKA. METHODS: To determine interrater reliability, 32 patients (81.3% female) were assessed by two examiners. Patients were assessed consecutively by both examiners on the same individual test dates. To determine intrarater reliability, a subgroup (n = 13) was again assessed by the examiners within four weeks of the initial testing procedure. Maximal isometric knee flexor and extensor strength were tested using a modified Citec hand-held dynamometer. Both the affected and unaffected knee were tested. Reliability was assessed using the Intraclass Correlation Coefficient (ICC). In addition, the Standard Error of Measurement (SEM) and the Smallest Detectable Difference (SDD) were used to determine reliability. RESULTS: In both the affected and unaffected knee, the inter- and intrarater reliability were good for knee flexors (ICC range 0.76-0.94) and excellent for knee extensors (ICC range 0.92-0.97). However, measurement error was high, displaying SDD ranges between 21.7% and 36.2% for interrater reliability and between 19.0% and 57.5% for intrarater reliability. Overall, measurement error was higher for the knee flexors than for the knee extensors. CONCLUSIONS: Modified HHD appears to be a reliable strength measure, producing good to excellent ICC values for both inter- and intrarater reliability in a group of TKA patients. High SEM and SDD values, however, indicate high measurement error for individual measures. This study demonstrates that a modified HHD is appropriate to evaluate knee strength changes in TKA patient groups. However, it also demonstrates that modified HHD is not suitable to measure individual strength changes. The use of modified HHD is, therefore, not advised for use in a clinical setting.

Kinematic and clinical evaluation of shoulder function after primary and revision reverse shoulder prostheses.

HYPOTHESIS: Results of the reverse shoulder prosthesis on pain are generally satisfying; however, active range of motion (ROM) is often not optimal, especially after revision. A kinematic and clinical analysis of the reverse prosthesis was performed to provide more precise information on its glenohumeral motion pattern. We hypothesized that the difference in the primary and revision cases is due to differences in the motion in the glenohumeral joint. MATERIALS AND METHODS: The motion pattern of 31 patients with a reverse prosthesis (35 shoulders, 19 primary and 16 revisions) was measured during 3 active ROM tasks-forward flexion, abduction, and axial rotation. Average age was 71 ± 8 years (range, 58-85 years). Average follow-up was 23 ± 14 months (range, 4-63 months). Kinematic measurements were performed with a 3-dimensional electromagnetic tracking device. Clinical evaluation was performed by obtaining Constant score, Disabilities of Arm, Shoulder and Hand (DASH) score, and the Simple Shoulder Test (SST). Acromial-prosthetic distance was measured on anteroposterior radiographs. RESULTS: Primary placed prostheses showed significantly better active glenohumeral motion than revisions for forward flexion (71° ± 18° vs 53° ± 26°, P < .05), abduction (64° ± 15° vs 46° ± 24°, P < .05), and active external rotation (31° ± 25° vs 13° ± 16°, P < .05). Constant score improved for the whole group from 24 (range, 5-47) to 50 (range, 8-87; P < .001), for the primary group from 28 (range, 13-47) to 60 (range, 8-87; P < .001) and for revisions from 20 (range, 5-47) to 38 (range, 11-73; P < .001). Acromial-prosthetic distance showed no significant correlation for active glenohumeral motion. Five shoulders with a deficient teres minor muscle showed no significant decrease of external rotation. CONCLUSION: Active ROM is better in primary placed prosthesis, and this difference takes place mainly in the glenohumeral joint. In all our patients, Constant scores improved significantly postoperatively. However, we could not find any clinical correlating parameters to explain this difference.

Measuring mobility limitations in children with cerebral palsy: content and construct validity of a mobility questionnaire (MobQues).

AIM: the objective of this study was to assess the validity of a mobility questionnaire (MobQues) that was developed to measure parent-reported mobility limitations in children with cerebral palsy (CP). METHOD: the parents of 439 children with CP (256 males and 183 females; age range 2-18y; Gross Motor Function Classification System [GMFCS] levels I-IV) completed the mobility questionnaire (MobQues). To assess content validity, we linked all meaningful concepts of the MobQues items to the International Classification of Functioning, Disability and Health (ICF). To assess construct validity, we compared the total scores of the two versions of the MobQues (MobQues47 and MobQues28) according to GMFCS level, and determined Pearson's correlation coefficient (r) with the Gross Motor Function Measure-66 (GMFM-66). RESULTS: content validity was demonstrated by the fact that 46 of the 47 MobQues items were linked to categories in the 'Mobility' chapter of the ICF. Construct validity was demonstrated by the finding that MobQues scores decreased with increasing GMFCS levels (p<0.001). In a subgroup of 162 children, positive correlations were found between total scores and the GMFM-66 (MobQues47, r=0.75; MobQues28, r=0.67, p<0.001). INTERPRETATION: the results of this study provide evidence supporting the content and construct validity of the MobQues as a measure of mobility limitation in children with CP.

Measuring mobility limitations in children with cerebral palsy: interrater and intrarater reliability of a mobility questionnaire (MobQues).

AIM: The objective of this study was to assess the reliability of a mobility questionnaire (MobQues) that was developed to measure the mobility limitations of children with cerebral palsy (CP) as rated by their parents. A clinical version of the questionnaire, consisting of 47 items (MobQues47), is available, as well as a research version with 28 items for a specific population (MobQues28). Total scores are expressed on a scale of 0 to 100. METHOD: We assessed the interrater reliability between both parents of 289 children with CP (168 males, 121 females, age range 2-13 y, Gross Motor Function Classification System levels I-IV) and the intrarater reliability within a subgroup of 38 parents (of 23 children) who completed the MobQues twice. RESULTS: For the interrater reliability, high intraclass correlation coefficients (ICCs) were found for the MobQues47 (ICC 0.92) and MobQues28 (ICC 0.87). The standard error of measurement (SEM) was 7.8 and 8.9 respectively. As expected, the intrarater reliability was higher, as represented by higher ICCs (0.96-0.99) and lower SEMs (3.5-4.9) for both MobQues versions. INTERPRETATION: The results of this study indicate that the MobQues is a reliable instrument to measure the mobility limitations of children with CP.

Effectiveness of functional progressive resistance exercise strength training on muscle strength and mobility in children with cerebral palsy: a randomized controlled trial.

AIM: To evaluate the effectiveness of functional progressive resistance exercise (PRE) strength training on muscle strength and mobility in children with cerebral palsy (CP). METHOD: Fifty-one children with spastic uni- and bilateral CP; (29 males, 22 females; mean age 10 y 5 mo, SD 1 y 10 mo, range 6 y 0 mo-13 y 10 mo; Gross Motor Function Classification System levels I-III) were randomized to the intervention group (n=26) or the control group (n=25, receiving usual care). The intervention group trained for 12 weeks, three times a week, on a five-exercise circuit, which included a leg-press and functional exercises. The training load progressively increased based on the child's maximum level of strength, determined by the eight-repetition maximum. Muscle strength (measured with hand-held dynamometry and a six-repetition maximum leg-press test), mobility (measured with the Gross Motor Function Measure, two functional tests, and a mobility questionnaire), and spasticity (measured by the appearance of a catch) were evaluated before, during, directly after, and 6 weeks after the end of training by two blinded research assistants. RESULTS: Directly after training, there was a statistically significant effect (p<0.05) on muscle strength (knee extensors +12% [0.56 N/kg; 95% confidence interval {CI} 0.13-0.99]; hip abductors +11% [0.27 N/kg; 95% CI 0.00-0.54]; total +8% [1.30 N/kg; 95% CI 0.56-2.54]; six-repetition maximum +14% [14%; 95% CI 1.99-26.35]), but not on mobility or spasticity. A detraining effect was seen after 6 weeks. INTERPRETATION: Twelve weeks of functional PRE strength training increases muscle strength up to 14%. This strength gain did not lead to improved mobility.

Evaluation of the catch in spasticity assessment in children with cerebral palsy.

OBJECTIVE: To evaluate whether the catch in clinical spasticity assessment in cerebral palsy (CP) is the consequence of a sudden velocity-dependent increase in muscle activity, resulting from hyperexcitability of the stretch reflex in spasticity. DESIGN: Cross-sectional study. SETTING: A special school for children with physical disabilities. PARTICIPANTS: Children with CP (N=20; age range, 5-14y; mean weight +/- SD, 35+/-14kg; mean length +/- SD, 139+/-19cm). INTERVENTIONS: Spasticity assessment tests (using slow and fast passive stretch) were performed in the medial hamstrings, soleus, and medial gastrocnemius muscles of the children by 2 experienced examiners. MAIN OUTCOME MEASURES: Surface electromyography (EMG) was recorded and joint motion was simultaneously measured using 2 inertial sensors. The encounter of a catch by the examiner was compared with the presence of a sudden increase in muscle activity ("burst"). The average rectified value (ARV) of the EMG signal was calculated for each test. RESULTS: The study shows a sudden increase in muscle activity in fast passive stretch, followed by a catch (hamstrings 100%, soleus 95%, gastrocnemius 84%). The ARV in slow passive stretch was significantly lower. CONCLUSIONS: The results confirm that in children with CP, an increase in muscle activity is primarily responsible for a catch in fast passive muscle stretch.