Victor Lun

Knee Angular Impulse as a Predictor of Patellofemoral Pain in Runners

Background Identification of mechanical factors associated with patellofemoral pain, the most prevalent running injury, is necessary to help in injury prevention, but unfortunately they remain elusive. Hypothesis Runners who develop patellofemoral pain have increased knee joint angular impulse in the frontal plane. Study Design Case control study; Level of evidence, 3. Methods A retrospective study compared knee abduction impulses of 20 patellofemoral pain patients with those of 20 asymptomatic patients. A second prospective study quantified knee angular impulses during the stance phase of running of 80 runners at the beginning of the summer running season. Epidemiologic data were then collected, recording the type and severity of injury of these runners during a 6-month running period. Results The patellofemoral pain patients in the retrospective study had significantly higher (P =. 026) knee abduction impulses (17.0 ± 8.5 Nms) than did the asymptomatic patients (12.5 ± 5.5 Nms). Six patients developed patellofemoral pain during the prospective study. The prospective data showed that patients who developed patellofemoral pain had significantly higher (P =. 042) knee abduction impulses (9.2 ± 3.7 Nms) than did matched patients who remained uninjured (4.7 ± 3.5 Nms). Conclusion The data indicate that increased knee abduction impulses should be deemed risk factors that play a role in the development of patellofemoral pain in runners. Clinical Relevance Footwear and running style can influence knee angular impulse, and the appropriate manipulation of these variables may play a preventive role for patients who are predisposed to patellofemoral pain.

Effectiveness of patellar bracing for treatment of patellofemoral pain syndrome.

Objective:To determine the effectiveness of patellar bracing for treatment of patellofemoral pain syndrome (PFPS). Design:Prospective, randomized, single-blinded clinical trial. Setting:Subjects recruited from the general population of the city of Calgary. Subjects:A total of 136 subjects (79 females and 57 males with a total of 197 affected knees) diagnosed with PFPS. Intervention:Subjects were randomly assigned to 1 of 4 treatment groups: (1) home exercise program, (2) patellar bracing, (3) home exercise program with patellar bracing, and (4) home exercise program with knee sleeve. Outcome Measures:The outcome measurements were knee function (KF) and 10-cm visual analogue scale (VAS) pain ratings for 3 different situations: knee pain during sport activity, knee pain 1 hour after sport activity, and knee pain after sitting with knees bent for 30 minutes. The outcome measurements were assessed at baseline and at 3, 6, and 12 weeks. The investigators were blinded to the treatment group of each subject. Calculations were made for 95% confidence intervals for the change in KF and VAS pain ratings from baseline measurement to 12 weeks. Results:There was no difference in the 95% confidence intervals in the change of KF and VAS pain ratings among the 4 treatment groups over 12 weeks. Conclusions:Symptoms of PFPS improved over time in terms of pain and knee function regardless of the treatment group. Patellar bracing did not improve the symptoms of PFPS more quickly when added to a home program of leg strengthening. However, patellar bracing alone can improve the symptoms of PFPS.

Diminished cartilage‐lubricating ability of human osteoarthritic synovial fluid deficient in proteoglycan 4: Restoration through proteoglycan 4 supplementation

OBJECTIVE The purposes of this study were 1) to quantify the proteoglycan 4 (PRG4) and hyaluronan (HA) content in synovial fluid (SF) from normal donors and from patients with chronic osteoarthritis (OA) and 2) to assess the cartilage boundary-lubricating ability of PRG4-deficient OA SF as compared to that of normal SF, with and without supplementation with PRG4 and/or HA. METHODS OA SF was aspirated from the knee joints of patients with symptomatic chronic knee OA prior to therapeutic injection. PRG4 concentrations were measured using a custom sandwich enzyme-linked immunosorbent assay (ELISA), and HA concentrations were measured using a commercially available ELISA. The molecular weight distribution of HA was measured by agarose gel electrophoresis. The cartilage boundary-lubricating ability of PRG4-deficient OA SF, PRG4-deficient OA SF supplemented with PRG4 and/or HA, and normal SF was assessed using a cartilage-on-cartilage friction test. Two friction coefficients (μ) were calculated: static (μ(static, Neq) ) and kinetic () (where N(eq) represents equilibrium axial load and angle brackets indicate that the value is an average). RESULTS The mean ± SEM PRG4 concentration in normal SF was 287.1 ± 31.8 μg/ml. OA SF samples deficient in PRG4 (146.5 ± 28.2 μg/ml) as compared to normal were identified and selected for lubrication testing. The HA concentration in PRG4-deficient OA SF (mean ± SEM 0.73 ± 0.08 mg/ml) was not significantly different from that in normal SF (0.54 ± 0.09 mg/ml). In PRG4-deficient OA SF, the molecular weight distribution of HA was shifted toward the lower range. The cartilage boundary-lubricating ability of PRG4-deficient OA SF was significantly diminished as compared to normal (mean ± SEM = 0.043 ± 0.008 versus 0.025 ± 0.002; P < 0.05) and was restored when supplemented with PRG4 ( = 0.023 ± 0.003; P < 0.05). CONCLUSION These results indicate that some OA SF may have decreased PRG4 levels and diminished cartilage boundary-lubricating ability as compared to normal SF and that PRG4 supplementation can restore normal cartilage boundary lubrication function to these OA SF.

Comparison of the effects of a self-supervised home exercise program with a physiotherapist-supervised exercise program on the motor symptoms of Parkinson's disease.

The effects of a self‐supervised home exercise program and a physiotherapist‐supervised exercise program on motor symptoms in Parkinsons disease (PD) patients were compared in a prospective single‐blinded clinical trial. Nineteen subjects (6 women, 13 men; mean age, 65 ± 8 years) with Hoehn and Yahr Stages 2 to 3 were recruited. Subjects were self‐selected into an 8‐week exercise program that was self‐supervised (HOME group) or physiotherapist‐supervised (PT group). The primary outcome measurement was the Unified Parkinsons Disease Rating Scale (UPDRS) Motor subsection score (UPDRSm). The secondary outcome measurements were the Berg Balance Scale, Timed Up and Go Test, UPDRS Total score, and the Activities‐specific Balance Confidence Scale. All outcomes were assessed at baseline and at 8 and 16 weeks after the start of the study. The investigators were blinded to the subject treatment group. Bonferroni‐corrected paired Students t test was used to evaluate the change in the UPDRSm from baseline to 8 weeks. Ninety‐five percent confidence intervals (CI) were calculated for the change in the secondary outcome measurements from baseline to 8 weeks. There was statistically significant and equal decrease in the UPDRSm from baseline to 8 weeks in both treatment groups. There was no difference in the 95% CI in the change of the secondary outcome measurements. A self‐supervised exercise program was found to have similar effectiveness as a physiotherapist‐supervised exercise program in improving motor symptoms in PD patients. This finding is important in the counseling of PD patients regarding adjunctive treatment of motor symptoms of PD with exercise.

Injuries in Short Track Speed Skating

Background Little is known about the pattern of injury in short track speed skating. Purpose To investigate the incidence and characteristics of injuries in short track speed skating. Study Design Retrospective study. Methods Ninety-five of 150 elite-level skaters (63.3%) were surveyed to collect information on training and competition load as well as on injuries sustained during the 1999—2000 competitive season. Injuries were characterized in terms of anatomic location, type of injury, time loss from training and competition, and circumstance of injury (acute onset during competition, on-ice practice, off-ice training, or insidious onset). Results Sixty-one of the 95 skaters (64.2%) reported sustaining at least one injury. The knee, ankle, spine, leg, and groin were the most commonly reported sites of injury. Skaters were also asked to list previous on-ice injuries. The two most common injuries occurring on-ice before the 1999—2000 season were lacerations from the knee down (11.1%) and ankle fractures (10.2%). Conclusion The results of this study suggest that there is a high incidence of injury in competitive short track speed skating.

Efficacy of Hip Strengthening Exercises Compared With Leg Strengthening Exercises on Knee Pain, Function, and Quality of Life in Patients With Knee Osteoarthritis.

Objective:The purpose of this study was to compare the efficacy of hip and leg strengthening exercise programs on knee pain, function, and quality of life (QOL) of patients with knee osteoarthritis (KOA). Design:Single-Blinded Randomized Clinical Trial. Setting:Patients with KOA. Participants:Male and female subjects were recruited from patients referred to the University of Calgary Sport Medicine Center and from newspaper advertisements. Interventions:Thirty-seven and 35 patients with KOA were randomly assigned to either a 12-week hip or leg strengthening exercise program, respectively. Both exercise programs consisted of strengthening and flexibility exercises, which were completed 3 to 5 days a week. The first 3 weeks of exercise were supervised and the remaining 9 weeks consisted of at-home exercise. Main Outcome Measures:Knee Injury and Osteoarthritis Score (KOOS) and Western Ontario McMaster Arthritis Index (WOMAC) questionnaires, 6-minute walk test, hip and knee range of motion (ROM), and hip and leg muscle strength. Results:Statistically and clinically significant improvements in the KOOS and WOMAC pain subscale scores were observed in both the hip and leg strengthening programs. There was no statistical difference in the change in scores observed between the 2 groups. Equal improvements in the KOOS and WOMAC function and QOL subscales were observed for both programs. There was no change in hip and knee ROM or hip and leg strength in either group. Conclusions:Isolated hip and leg strengthening exercise programs seem to similarly improve knee pain, function, and QOL in patients with KOA. Clinical Relevance:The results of this study show that both hip and leg strengthening exercises improve pain and QOL in patients with KOA and should be incorporated into the exercise prescription of patients with KOA.

Reduced knee adduction moments for management of knee osteoarthritis:: A three month phase I/II randomized controlled trial

Wedged insoles are believed to be of clinical benefit to individuals with knee osteoarthritis by reducing the knee adduction moment (KAM) during gait. However, previous clinical trials have not specifically controlled for KAM reduction at baseline, thus it is unknown if reduced KAMs actually confer a clinical benefit. Forty-eight participants with medial knee osteoarthritis were randomly assigned to either a control group where no footwear intervention was given, or a wedged insole group where KAM reduction was confirmed at baseline. KAMs, Knee Injury and Osteoarthritis Outcome Score (KOOS) and Physical Activity Scale for the Elderly (PASE) scores were measured at baseline. KOOS and PASE surveys were re-administered at three months follow-up. The wedged insole group did not experience a statistically significant or clinically meaningful change in KOOS pain over three months (p=0.173). Furthermore, there was no association between change in KAM magnitude and change in KOOS pain over three months within the wedged insole group (R2=0.02, p=0.595). Improvement in KOOS pain for the wedged insole group was associated with worse baseline pain, and a change in PASE score over the three month study (R2=0.57, p=0.007). As an exploratory comparison, there was no significant difference in change in KOOS pain (p=0.49) between the insole and control group over three months. These results suggest that reduced KAMs do not appear to provide any clinical benefit compared to no intervention over a follow-up period of three months. ClinicalTrials.gov ID Number: NCT02067208.

A three dimensional approach for quantifying resultant loading at the knee

BACKGROUND Clinical effectiveness of lateral wedges for knee osteoarthritis is inconsistent across studies. One explanation is that knee loading is not fully described by the peak frontal-plane knee moment. The purpose of this study was to propose a 3D resultant approach to describing moments at the knee and evaluate how this moment changes in response to lateral wedges. METHODS Walking gait analysis was performed on 20 individuals with knee osteoarthritis, in their own shoes, with and without a six millimeter lateral wedge insole. Frontal-plane and 3D resultant moments were calculated for each participant and footwear condition. Paired t-tests identified differences between footwear conditions, correlations identified relationships between frontal-plane and 3D resultant moments, and regressions assessed relationships between moments and pain. RESULTS Significant reductions to peak frontal-plane moments (p=0.001) and 3D resultant moments at the same time point (p=0.042) were observed with lateral wedges. While an overall significant correlation was observed between change in frontal-plane moments and change in 3D resultant moments with a lateral wedge (r=0.68, p=0.001), 5/20 participants experienced disparate results where the frontal-plane moment was reduced yet the 3D moment increased. CONCLUSIONS While lateral wedges alter frontal-plane moment magnitude, the direction of change does not always correspond to the direction of change observed in the 3D resultant moment. Thus resultant knee load may sometimes increase with lateral wedges. CLINICAL RELEVANCE Future prospective studies should evaluate if changes in 3D resultant moments, and thus total knee load, offer an explanation as to why some participants do not experience clinical benefit from lateral wedges.

A new app for physicians on environmental medicine

The purpose of the “Medicine in Challenging Environments” app, published in 2014 by the Mayo Clinic, is stated as “. . . to provide practical, evidence-based multi-specialty knowledge . . .” for the primary care physician to provide guidance for their patients who engage in high adventure activities and to assist high adventurers in their planning for such activities. The app editors are 3 Mayo Clinic physicians: Dr. Jan Stepanek (internist and aerospace medicine), Dr. Robert Johnson (pediatrician) and Dr. Daniela Cocco (Mayo Clinic Aerospace Medicine and Vestibular Research Laboratory researcher). The content of the application is organized in 3 main sections with multiple chapters in each section: Environments, Specific Clinical Problems and Special Considerations. This “app” is essentially a book. Navigation through the app is similar to most book-type apps. The “Home” tab leads to an introduction and hypoxia, temperature and wind/pressure calculators. The “Chapters” tab leads to all the book chapters. Each chapter is broken down into subsections. Swiping up/down scrolls a single page and swiping left and right changes pages, sections and chapters. The app is searchable by keyword. The only interactive aspects of the app are the hypoxia, temperature and wind/ pressure calculators. The content of the “Environments” section focuses on the human physiology and medical/clinical considerations as related to exposure to extremes of environmental conditions including hyper/hypo-gravity, altitude, hydration, ionizing radiation, thermal, etc.. There is also a chapter on motor sports but there is no specific chapter or content dedicated to undersea/hyperbaric medicine. The content of the “Specific Clinical Problems” focuses on medical sub-specialty specific management of travel-related medical problems and is not really related directly to the “Environments” section of the app. Each chapter has “Clinical Vignette(s)” which describes a clinical case(s) that a clinician may encounter, which enhances the practical aspect of the app. The content of the “Special Considerations” section has chapters focusing on survival strategies. For the clinician without knowledge or previous experience in guiding patients who might be facing extreme environmental conditions, this app would be a very good basic reference. The editors do attempt to make the information practical by including clinical cases (“Clinical Vignettes”). However, the challenge with any clinical reference is that it is difficult to anticipate every clinical scenario that one may face and every chapter of book could be a book in and of themselves. Moreover, clinical practice can change very quickly, so the information needs to be updated frequently. The most useful section of the app, as it relates to the title of the app, is the “Environments” section. The “Hydration” and “Thermal” chapters of this section, written by Dr. Stephen Cheung of Brock University (Canada), and Dr. Christopher Tyler of Roehampton University (UK), 2 physiologists with extensive research background in the fields, are very thorough and provide very practical information related to strategies for managing one’s hydration and how to deal with heat and cold stress, respectively. The “Specific Clinical Problems” section is essentially a Travel Medicine reference. The “Special Considerations” section has survival strategies chapters. Some added interactivity within each chapter would make the app more interesting. Medicine in Challenging Environments is available in the Apple App Store, and is compatible with iPad but not iPhone or Mac OS. Currently

Dietary Supplementation Practices in Canadian High-Performance Athletes

CAN 9.99, the app is reasonably priced.