Do individuals with knee osteoarthritis walk with distinct knee biomechanics and muscle activation characteristics? An investigation of knee osteoarthritis, hip osteoarthritis, and asymptomatic groups.

BACKGROUND: Biomechanical markers including reductions in sagittal plane kinematics and moments, increases in knee adduction moments (KAM), and altered muscle activations have been identified as hallmark indicators of knee osteoarthritis (OA). However, it remains unknown whether these features of knee OA gait are exclusive to the diseased joint. RESEARCH QUESTION: To determine whether specific gait outcomes previously linked to symptomatic medial compartment knee OA are unique to knee OA by concurrently investigating a group of asymptomatic individuals and those with hip OA. METHODS: 16 individuals with moderate medial compartment knee OA, 16 individuals with moderate hip OA, and 16 asymptomatic controls were recruited. Participants walked on a treadmill while segment kinematics and ground reaction forces were recorded. Sagittal plane kinematics and sagittal and frontal plane moments were calculated. Surface electromyograms were recorded from lateral and medial hamstrings and gastrocnemius and vastus lateralis and medialis. Discrete variable analysis was used to investigate knee joint mechanics and muscle activation ratios. Analysis of Variance models using Bonferroni corrections determined between group differences (α = 0.0167). RESULTS: Sagittal plane knee kinematics and moments were statistically similar among all groups (p > 0.0167). No differences were found for peak KAM and impulse between knee OA and asymptomatic groups (p > 0.0167) but peak KAM (p = 0.006 and impulse (p = 0.001) were greater in the knee OA group compared to hip OA. The hip OA group had a lower KAM impulse (p < 0.0167) compared to the knee OA and asymptomatic groups. A greater LH:MH activation ratio (p < 0.0167) was found in the knee OA group compared to hip OA and asymptomatic groups. No other activation ratio differences were found (p > 0.0167). SIGNIFICANCE: Medial and lateral hamstring muscle activation levels may provide utility as a knee OA gait biomarker compared to biomechanical outcomes, quadriceps and gastrocnemius activation, when differentiating knee OA from asymptomatic and hip OA cohorts.

The effect of a frontal plane gait perturbation bout on knee biomechanics and muscle activation in older adults and individuals with knee osteoarthritis.

BACKGROUND: Walking can be a challenging task for individuals with knee osteoarthritis and many older adults. The purpose was to determine the immediate effect of a frontal plane perturbation bout during walking on knee biomechanics and muscle activation patterns in these groups. METHODS: 44 asymptomatic older adults and 32 individuals with knee osteoarthritis were recruited. Sagittal and frontal plane knee biomechanics and muscle activation levels were calculated and recorded during treadmill walking. After a baseline collection at 6-min, a random series of unexpected medial/lateral walkway surface perturbations were delivered over approximately 24 min. Data was collected immediately after the perturbations. Discrete measures extracted from biomechanical waveforms, and principal component analysis to analyze muscle activation were utilized to determine time effects and interactions using analysis of variance models (alpha = 0.05). FINDINGS: After the perturbation bout, sagittal plane range of motion was significantly increased in the osteoarthritis group (Effect Size = 0.24) and in both groups peak knee adduction moment (Effect Size = 0.10) and difference between peak flexion and extension moments (Effect Size = 0.16) were significantly increased. Muscle amplitudes in both groups were significantly reduced (PP1-scores) after perturbation bout, whereas significant time-based gait cycle activation pattern alterations identified by PP2- and PP3-scores were related to group and muscle assignment. INTERPRETATION: Perturbations were tolerated by all participants, resulting in significant alterations to biomechanical outcomes and muscle activation levels and patterns. Demand on the knee joint was not increased after perturbations. Gait perturbation training in these groups may be feasible using a frontal plane perturbation bout.

Arthroscopy Association of Canada Position Statement on Exercise for Knee Osteoarthritis: A Systematic Review of Guidelines.

BACKGROUND: Exercise is widely regarded to improve pain and function in patients with knee osteoarthritis (OA) through building supportive muscle mass, facilitating weight loss, and through the other beneficial effects associated with it. PURPOSE: To explore literature that presents clinical guidelines for the use of exercise in the treatment of knee OA to inform an evidence-based position statement for the Arthroscopy Association of Canada. STUDY DESIGN: Position statement. METHODS: PubMed, MEDLINE, Embase, and Cochrane databases were searched for guidelines commenting on the role of exercise for knee OA. The search was limited to guidelines published in the last 10 years. Articles were screened for relevance, focusing on recently published research with clinical guidelines. Inclusion criteria involved all articles providing clinical guidelines for exercise and knee OA. RESULTS: Eight guidelines were identified. All eight recommended exercise as an important component of treatment for knee OA, with 6/8 strongly recommending it. CONCLUSION: Exercise is an effective and important component of the non-pharmacological management of knee OA. The Arthroscopy Association of Canada strongly recommends the use of exercise in the management of knee OA.

Limiting the Risk of Osteoarthritis After Anterior Cruciate Ligament Injury: Are Health Care Providers Missing the Opportunity to Intervene?

OBJECTIVE: To understand what sports orthopedic surgeons (OS), primary care physicians (PCPs) with sports medicine training, and physical therapists (PTs) managing nonelite athletes with anterior cruciate ligament (ACL) injury tell their patients about their osteoarthritis (OA) risk. METHODS: An electronic survey was distributed by the Canadian Academy of Sport and Exercise Medicine (PCPs, OS), the Sports and Orthopedic Divisions of the Canadian Physiotherapy Association (PTs), and to OS identified through the Royal College of Physicians and Surgeons and the Canadian Orthopaedic Association. The survey included 4 sections: demographics, factors discussed, timing of discussions, and discussion of risk factors and their management. Proportions or means with 95% confidence intervals were calculated. RESULTS: A total of 501 health care professionals (HCPs) responded (98 PCPs, 263 PTs, and 140 OS). Of those responding, 70-77% of physicians reported always discussing OA risk, but only 35% of PTs did. All HCPs reported that patient activities perceived as detrimental to knee health, ACL reinjury, and simultaneous injury to other structures in the knee were most often the reason for discussing OA risk. OA risk was discussed at initial management post-injury (65-94%), with few discussing risk subsequently. Eighty percent of physicians and 99% of PTs indicated that PTs were suited to provide OA risk and management information. CONCLUSION: HCPs routinely managing people with ACL injury do not consistently discuss OA risk post-injury with them. Educational strategies for HCPs are urgently needed to develop care pathways inclusive of support for OA risk management following ACL injury.

Differences in Baseline Joint Moments and Muscle Activation Patterns Associated With Knee Osteoarthritis Progression When Defined Using a Clinical Versus a Structural Outcome.

Both structural and clinical changes can signify knee osteoarthritis progression; however, these changes are not always concurrent. A better understanding of mechanical factors associated with progression and whether they differ for structural versus clinical outcomes could lead to improved conservative management. This study examined baseline gait differences between progression and no progression groups defined at an average of 7-year follow-up using 2 different outcomes indicative of knee osteoarthritis progression: radiographic medial joint space narrowing and total knee arthroplasty. Of 49 individuals with knee osteoarthritis who underwent baseline gait analysis, 32 progressed and 17 did not progress using the radiographic outcome, while 13 progressed and 36 did not progress using the arthroplasty outcome. Key knee moment and electromyography waveform features were extracted using principal component analysis, and confidence intervals were used to examine between-group differences in these metrics. Those who progressed using the arthroplasty outcome had prolonged rectus femoris and lateral hamstrings muscle activation compared with the no arthroplasty group. Those with radiographic progression had greater mid-stance internal knee rotation moments compared with the no radiographic progression group. These results provide preliminary evidence for the role of prolonged muscle activation in total knee arthroplasty, while radiographic changes may be related to loading magnitude.

Arthroscopic Anatomic Glenoid Reconstruction Without Subscapularis Split.

The role of bone loss from the anterior glenoid in recurrent shoulder instability has been well established. We present a completely arthroscopic technique for reconstructing the anterior glenoid with distal tibial allograft and without a subscapularis split. We perform the arthroscopy in the lateral position. We measure and size an allograft distal tibial graft and place it arthroscopically. We use an inside-out medial portal to introduce the graft into the shoulder, passing it through the rotator interval and above the subscapularis. A double-cannula system is used to pass the graft, which is temporarily fixed with K-wires and held in place with cannulated screws. We then perform a Bankart-like repair of the soft tissues to balance the shoulder and augment our repair. Our technique is not only anatomic in the re-creation of the glenoid surface but also anatomic in the preservation of the coracoid and subscapularis tendon and repair of the capsulolabral complex.

Lateral Decubitus All-Arthroscopic Latarjet Procedure for Treatment of Shoulder Instability.

Shoulder instability can be a challenging condition to treat when it becomes refractory to soft-tissue procedures or when bone loss exceeds 25% to 27% of the glenoid. The Bristow-Latarjet procedure has been developed and popularized to deal with these concerns. Traditionally, the procedure has been performed as an open approach; however, this has been recently supplanted by novel arthroscopic techniques. We present a technique for the procedure performed with the patient in a semi-lateral decubitus position that assists with optimal graft placement on the native glenoid. We use the cannulated Bristow-Latarjet Instability Shoulder System (DePuy Mitek, Raynham, MA). After a diagnostic arthroscopic evaluation, we use multiple arthroscopic anterior portals to debride the rim of the glenoid. The coracoid is prepared and taken down arthroscopically, and the cannulated guide is attached and advanced through an arthroscopically created subscapularis split. With the shoulder held in a reduced position, we are then able to drill and anchor the graft to the native glenoid. The patient is able to begin gentle range-of-motion exercises immediately postoperatively.

Systematic instruction of arthroscopic knot tying with the ArK Trainer: an objective evaluation tool.

PURPOSE: A Proficiency Formula was introduced as an objective self-evaluation method for evaluating basic arthroscopic knot tying in a laboratory setting. The correlation between the Proficiency Formula and gold standard pass/fail dichotomy was demonstrated, as well as with other popular evaluation tools--task-specific checklist (TSC) and global rating scale (GRS). METHOD: A step-by-step video tutorial was used to instruct 35 medical students on how to tie an arthroscopic Samsung Medical Center (SMC) knot secured by three half hitches. Participants were video recorded performing arthroscopic knot tying and assessed on their success tying an SMC knot, pass or fail, and through three outcome tools: the Proficiency Formula, GRS and the TSC. Independent samples t test was used to compare the GRS, TSC and Proficiency Formula scores, between those who were passed or failed by the evaluators. Correlation between the measurement scales was tested using Spearman's rho correlation coefficient. RESULTS: Participants received a mean proficiency score of 195 (140-249). The mean Proficiency score for those that passed was 323 (95 % CI 272-374), for those that failed, 87 (95 % CI 26-148, p < 0.001). We found strong linear correlation between the Proficiency Formula and GRS and TSE (0.83 and 0.78, respectively). CONCLUSION: The Proficiency Formula has high correlation with gold standard GRS and TSC measurements when used to assess arthroscopic knot tying skills on a model. It has the added advantage of being able to be self-assessed.

Construct validity testing of the Arthroscopic Knot Trainer (ArK).

PURPOSE: This study introduced a novel simulator called the Arthroscopic Knot Trainer (ArK) and reports preliminary evidence to support its construct validity. To our knowledge, the ArK is the first non-anatomical tissue reduction simulator designed to meet learning objectives specific for developing knot-tying skills. MATERIALS AND METHODS: A step-by-step instructional video was used to teach orthopaedic residents how to tie an arthroscopic SMC knot. Residents were video recorded to assess time of completion, number of knots tied in 10 min and re-assessed 6 months later. Subjects were surveyed for content evidence after using the ArK. Data were analysed by paired t test and independent sample t test in order to compare the mean time to tie knots from test at baseline to retest at 6 months and the between group mean time, respectively. RESULTS: Content evidence supports the ArK trainer as appropriate for teaching and assessing arthroscopic knot-tying skills. Relation to other variables evidence supports the ArK trainer model whether stratified by year of training or by self-reported experience; time required for knot tying was inversely correlated with experience in tying arthroscopic knots. Internal structure evidence was supported with similar findings at retesting. CONCLUSIONS: There are three sources of evidence supporting the construct validity of the ArK as a simulator for arthroscopic knot tying: content, relationship to other variable and internal structure evidence. The ArK is easy to use and has the capacity to distinguish between groups with different skill levels.

Alpha angle correction in femoroacetabular impingement.

PURPOSE: The predictive value of the alpha angle, currently the most validated magnetic resonance imaging parameter for CAM-impingement FAI, remains to be systematically evaluated in the orthopaedic literature. A systematic review was conducted to determine whether alpha angle correction influences clinical outcomes in patients with FAI. METHODS: We searched three databases (MEDLINE, EMBASE and PubMed) for English clinical studies published up to August 2012, reporting surgical correction of the alpha angle in patients with a primary diagnosis of FAI. Two independent assessors reviewed eligible studies. Where applicable, the Newcastle-Ottawa Scale was used to perform a quality assessment. Descriptive statistics are presented. RESULTS: Of the 1,103 studies initially retrieved, 14 fulfilled our eligibility criteria. Majority of studies (86 %) were case-control designs, with no randomized controlled trials. Variability existed in the surgical techniques and modalities used to measure pre- and post-operative alpha angles. All 14 studies reported a mean measured post-operative restoration of a normal alpha angle (equal to or less than 55°). Failure due to inadequate osseous correction was cited in 3/14 included studies. Correction resulted in significant improvements in range of motion and patient Visual Analog Scales, non-arthritic hip scores, Harris Hip Scores and the short-form-12. CONCLUSION: Based on this review, there is evidence supporting that precise surgical restoration of the alpha angle in CAM-type FAI to a minimum of less than 55° will lead to improved patient outcomes. The alpha angle is a good predictor of outcome and represents a simple, reproducible and inexpensive guide that can be used intra-operatively and post-operatively.