Obesity is associated with prolonged activity of the quadriceps and gastrocnemii during gait.

PURPOSE: To examine the effect of obesity and its potential interaction with knee OA presence on the electromyography patterns of the major knee joint periarticular muscles during walking. SCOPE: One hundred and eighteen asymptomatic adults and 177 adults with moderate knee osteoarthritis were subdivided into categories of healthy weight (n = 77; 20 kg/m(2) < BMI < 25 kg/m(2)), overweight (n = 117; 25 kg/m(2) ⩽ BMI < 30 kg/m(2)), and obese (n = 101; BMI ⩾ 30 kg/m(2) based on their body mass index (BMI). All individuals underwent a three-dimensional gait analysis. Surface electromyograms from the lateral and medial gastrocnemii, lateral and medial hamstrings, vastus lateralis, vastus medialis, and rectus femoris were recorded during self-selected speed walking. Principal component analysis was used to extract major features of amplitude and temporal pattern variability from the electromyograms of each muscle group (gastrocnemii, quadriceps, hamstrings separately). Analysis of variance models tested for main BMI category effects and interaction effects for these features (α = 0.05). Statistically significant BMI category (i.e. obesity) effects were found for features that described more prolonged activations of the gastrocnemii and quadriceps muscles during the stance phase of gait with obesity (P < 0.05). CONCLUSIONS: Obesity was associated with prolonged activation of quadriceps and gastrocnemii, which can result in prolonged knee joint contact loading, and thereby may contribute to the predisposition of knee OA development and progression in obese individuals.

Quantitative 3D MRI reveals limited intra-lesional bony overgrowth at 1 year after microfracture-based cartilage repair.

OBJECTIVE: Intra-lesional bony overgrowth (BO) identified during or following cartilage repair treatment is being frequently described through subjective reports focusing primarily on incidence. Our objective was to quantify the exact volume of intra-lesional BO at 12 months post-cartilage repair treatment, to determine if a correlation exists between the extent of BO and clinical outcomes, and to visualize and characterize the BO. DESIGN: MRI scans were systematically obtained during a randomized clinical trial for cartilage repair (Stanish et al., 2013) that compared two microfracture-based treatments in 78 patients. Semi-automated morphological segmentation of pre-treatment, 1 and 12 months post-treatment scans utilizing a programmed anatomical atlas for all knee bone and cartilage structures permitted three-dimensional reconstruction, quantitative analysis, as well as qualitative characterization and artistic visualization of BO. RESULTS: Limited intra-lesional BO representing only 5.8 ± 5.7% of the original debrided cartilage lesion volume was found in 78 patients with available MRIs at 12 months. The majority (80%) of patients had very little BO (<10%). Most occurrences of BO carried either spotty (56.4%) or planar (6.4%) morphological features, and the remaining balance (37.2%) was qualitatively unobservable by eye. Pre-existing BO recurred at 12 months in the same intra-lesional location in 36% of patients. No statistical correlations were found between BO and clinical outcomes. CONCLUSIONS: Intra-lesional BO following microfracture-based treatments may not be as severe as previously believed, its incidence is partly explained by pre-existing conditions, and no relationship to clinical outcomes exists at 12 months. Morphologically, observable BO was categorized as comprising either spotty or planar bone.

Knee effusion affects knee mechanics and muscle activity during gait in individuals with knee osteoarthritis.

OBJECTIVE: To test the hypothesis that knee effusion presence in those with knee osteoarthritis (OA) alters knee joint muscle activation patterns and sagittal plane mechanics during gait. METHODS: Thirty-five patients with medial compartment knee OA were assessed for the presence of effusion using a brush test. Based on the results, they were assigned to the knee effusion (n = 17) and no knee effusion (n = 18) groups. Electromyograms from seven lower extremity muscles (lateral and medial gastrocnemius, vastus lateralis and medialis, rectus femoris and the lateral and medial hamstrings), leg motion and ground reaction forces were recorded during self-selected walking. Isometric knee extensor, plantar flexor and knee flexor strength were measured. Discrete measures from angular knee motion and net external moment of force waveforms were identified. Principal component analysis extracted electromyographic waveform features. Analysis of variance models tested for main effects (group, muscle) and interactions (α = 0.05). Bonferroni post-hoc testing was employed. RESULTS: No differences in age, body mass index, knee pain, Western Ontario McMaster Osteoarthritis Index scores, gait velocity and muscle strength were found between groups (P > 0.05). Individuals with effusion had a greater overall quadriceps activation and prolonged hamstring activation into mid-stance (P < 0.05). Knee joint flexion angles were higher (P < 0.05) and net external knee extension (KE) moments in mid to late stance lower in the effusion group. CONCLUSION: Quadriceps and hamstrings activation during walking were altered when effusions were present. Increased knee flexion (KF) angles and decreased KE moment in mid-late stance provide a mechanical explanation for the effect of joint effusion on muscle activation in those with knee OA.

The neuromuscular demands of altering foot progression angle during gait in asymptomatic individuals and those with knee osteoarthritis.

OBJECTIVES: To determine the immediate effects of a toe-out foot progression angle modification during gait on the major lower limb muscle activation characteristics and to establish whether asymptomatic individuals and those with moderate knee OA have similar responses. DESIGN: Seventeen patients with knee OA and 20 asymptomatic control subjects participated. Informed consent was obtained. Electromyographic (EMG) recordings were acquired from the lateral and medial gastrocnemii, vastus lateralis, vastus medialis, rectus femoris and the lateral and medial hamstrings during neutral and toe-out walking conditions. The EMG waveforms were amplitude normalized to maximal voluntary isometric contractions and time normalized to the gait cycle. Principal component analysis extracted principal waveform features. Analysis of variance models tested for main effects and interactions. Bonferroni post hoc testing was employed (alpha=0.05). RESULTS: Both groups altered foot progression angle by approximately 15 degrees during toe-out walking (P<0.05). A shift in gastrocnemius activation towards later stance (P<0.05) and increased magnitude and duration of quadriceps activation (P<0.05) was found. A differential activation occurred in the overall magnitude and principal shape of the lateral and medial hamstring musculature in the asymptomatic group only (P<0.05). Significant group differences were shown in each muscle analysis (P<0.05). CONCLUSION: Neuromuscular demands of adopting a toe-out gait differ from a neutral foot progression angle. Demands also differ between asymptomatic controls and patients with moderate knee OA. These findings have relevance for altered joint loading and changes in metabolic cost of this gait modification in individuals with knee OA.

Foot progression angle and the knee adduction moment: a cross-sectional investigation in knee osteoarthritis.

OBJECTIVE: To test the hypothesis that an association exists between the characteristics of the knee adduction moment and foot progression angle (FPA) in asymptomatic individuals and those with mild to moderate and severe knee osteoarthritis (OA). DESIGN: Fifty asymptomatic individuals, 46 patients with mild to moderate and 44 patients with severe knee OA were recruited. Maximum knee adduction moment during late stance and principal component analysis (PCA) were used to describe the knee adduction moment captured during gait. Multiple regression models were used for each of the three group assignments to analyze the association between the independent variables and the knee adduction moment. RESULTS: FPA explained a significant amount of the variability associated with the shape of the knee adduction moment waveform for the asymptomatic and mild to moderate groups (P<0.05), but not for the severe group (P>0.05). Walking velocity alone explained significant variance associated with the shape of the knee adduction moment in the severe OA group (P<0.05). CONCLUSION: A toe out FPA was associated with altered knee adduction moment waveform characteristics, extracted using PCA, in asymptomatic individuals and those with mild to moderate knee OA only. These findings are directly implicated in medial knee compartment loading. This relationship was not evident in those with severe knee OA.

Neuromuscular alterations during walking in persons with moderate knee osteoarthritis.

This paper compared the neuromuscular responses during walking between those with early-stage knee osteoarthritis (OA) to asymptomatic controls. The rationale for studying those with mild to moderate knee OA was to determine the alterations in response to dynamic loading that might be expected before severe pain, joint space narrowing and joint surface changes occur. We used pattern recognition techniques to explore both amplitude and shape changes of the surface electromyograms recorded from seven muscles crossing the knee joint of 40 subjects with knee OA and 38 asymptomatic controls during a walking task. The principal patterns for each muscle grouping explained over 83% of the variance in the waveforms. This result supported the notion that the main neuromuscular patterns were similar between asymptomatic controls and those with OA, reflecting the specific roles of the major muscles during walking. ANOVA revealed significant (p<0.05) differences in the principal pattern scores reflecting both amplitude and shape alterations in the OA group and among muscles. These differences captured subtle changes in the neuromuscular responses of the subjects with OA throughout different phases of the gait cycle and most likely reflected changes in the mechanical environment (joint loading, instability) and pain. The subjects with OA attempted to increase activity of the lateral sites and reduce activity in the medial sites, having minimal but prolonged activity during late stance. Therefore, alterations in neuromuscular responses were found even in this high functioning group with moderate knee OA.

The increasing need for nonoperative treatment of patients with osteoarthritis.

Osteoarthritis affects more patients than almost any other musculoskeletal disorder. The number of patients suffering joint pain and stiffness as a result of this disease will increase rapidly in the next decade. Although operative treatments of patients with osteoarthritis will continue to improve and the number of operative procedures will increase slightly in the next decade, only a small fraction of the patients with osteoarthritis will require operative procedures. The most pressing healthcare need for the majority of patients with osteoarthritis is nonoperative care that helps relieve symptoms and improve function, and in some instances slows progression. In rare instances, the symptoms of osteoarthritis improve spontaneously, but most patients need nonoperative care for decades. Orthopaedists need to improve their ability to provide nonoperative care for patients with osteoarthritis. They should be skilled in the early diagnosis of osteoarthritis and in the use of current common nonoperative treatments including patient education, activity modification, shoe modifications, braces, oral analgesics, oral nonsteroidal antiinflammatory medications, oral dietary supplements, and intraarticular injections. Furthermore, orthopaedists should be prepared to incorporate new nonoperative treatments for patients with osteoarthritis into their practice.

Chronic occupational repetitive strain injury.

OBJECTIVE: To review common repetitive strain injuries (RSIs) that occur in the workplace, emphasizing diagnosis, treatment, and etiology of these conditions. QUALITY OF EVIDENCE: A MEDLINE search from January 1966 to June 1999 focused on articles published since 1990 because RSIs are relatively new diagnoses. MeSH headings that were explored using the thesaurus included "cumulative trauma disorder," "overuse injury," and "repetitive strain injury." The search was limited to English articles only, and preference was given to randomized controlled trials. MAIN MESSAGE: Repetitive strain injuries result from repeated stress to the body's soft tissue structures including muscles, tendons, and nerves. They often occur in patients who perform repetitive movements either in their jobs or in extracurricular activities. Common RSIs include tendon-related disorders, such as rotator cuff tendonitis, and peripheral nerve entrapment disorders, such as carpal tunnel syndrome. A careful history and physical examination often lead to the diagnosis, but newer imaging techniques, such as magnetic resonance imaging and ultrasound, can help in refractory cases. Conservative management with medication, physiotherapy, or bracing is the mainstay of treatment. Surgery is reserved for cases that do not respond to treatment. CONCLUSION: Repetitive strain injury is common; primary care physicians must establish a diagnosis and, more importantly, its relationship to occupation. Treatment can be offered by family physicians who refer to specialists for cases refractory to conservative management.

The Natural History and Tailored Treatment of ACL Injury.

The fate of the injured anterior cruciate ligament (ACL) is variable. The spectrum of injury ranges from partial sprain (grade 1 or 2) to a complete disruption (grade 3), which may occur in isolation or in combination with injury to other structures in the knee. Postinjury symptoms of knee instability usually depend on the degree of joint laxity and the athletic demands of the individual. If an ACL injury is left untreated, repeated episodes of subluxation can inflict further intraarticular damage, with an increased risk of developing osteoarthritis. Predicting the outcome after ACL injury is difficult, and treatment should be individualized.

The young athlete with physical challenges.

This article is intentionally broad in scope, as a result of a collaboration from the fields of primary care sports medicine, orthopedic surgery, and kinesiology. What has been borne out in the process is a true appreciation of the benefits of a multidisciplinary approach toward providing care for the young athlete with a physical disability. To name a few, joint involvement of parents, coaches, trainers, physical therapists, orthotists, prosthetists, wheelchair engineers, neurologists, physiatrists, nutritionists and most importantly, the athletes themselves, should be further encouraged because each discipline provides a unique perspective in the identification and management of health-related issues. It is the intent of this article to provide readers with at least some new insight that they can carry into their future practice.

Eccentric kinetic chain exercise as a conservative means of functionally rehabilitating chronic isolated insufficiency of the posterior cruciate ligament.

OBJECTIVE: To determine the efficacy of a home eccentric kinetic chain exercise program in improving isokinetic strength, knee function, and symtomatology in athletes with isolated posterior cruciate ligament (PCL) injury. DESIGN: Experimental design. SETTING: Allan McGavin Sports Medicine Centre, University of British Columbia, Vancouver, British Columbia, Canada. PARTICIPANTS: The study included 13 athletes with isolated PCL injury (n = 13) and 13 healthy sedentary subjects (n = 13). All participants were men and between 18 and 35 years of age. The group with isolated PCL injury all had been diagnosed at the Allan McGavin Sports Medicine Centre, all had been treated without surgery, and had been injured at least 6 months ago. Diagnosis was based on presentation of a positive posterior sag and posterior drawer. INTERVENTION: The group with isolated PCL injury (treatment group) underwent 12 weeks of eccentric kinetic chain exercise. The control group of healthy sedentary individuals did not undergo any form of rigorous training during the course of this study. Both groups were tested for isokinetic strength, knee function, and symptomatology at weeks 0, 6, and 12. Compliance was insured through frequent phone contact and progressive journal records of completion of daily exercise. Only those who completely executed the 12-week exercise program were included in the study. MAIN OUTCOME MEASURES: Hamstring and quadriceps isokinetic torque (Nm) at constant velocities of 60 and 120 degrees per second (degrees/s), Tegner Hop Test (meters), and Lysholm Knee Scale scores. RESULTS: A subject-versus-treatment data analysis clearly indicated significant increases in eccentric and concentric torque over the 12-week period in the treatment group. Tegner Hop Test and Lysholm Knee Scale scores also increased significantly after the eccentric squat exercise program. Quadriceps eccentric/concentric ratios at both testing velocities increased significantly after 12 weeks of rehabilitation. There were no significant differences in strength between extremities in the treatment group at any time during the course of this study. Before rehabilitation, there were no significant differences between eccentric and concentric torque values in either muscle group (quadriceps and hamstrings) of the treatment group. After the eccentric exercise program, the quadriceps in the injured extremity did exhibit significantly greater eccentric than concentric torque. The treatment group was significantly weaker than the control group in eccentric torque at both testing velocities at week 0. After the 12-week exercise program, however, there were no significant differences between groups in eccentric quadriceps strength. CONCLUSION: The results of this investigation support the eccentric squat program as a viable means of functionally rehabilitating chronic PCL insufficiency.

Accuracy of screening compression ultrasonography and clinical examination for the diagnosis of deep vein thrombosis after total hip or knee arthroplasty.

OBJECTIVE: To determine whether compression ultrasonography or clinical examination should be considered as screening tests for the diagnosis of deep vein thrombosis (DVT) after total hip or knee arthroplasty in patients receiving warfarin prophylaxis postoperatively. DESIGN: A prospective cohort study. SETTING: A single tertiary care orthopedic centre. PATIENTS: One hundred and eleven patients who underwent elective total hip or knee arthroplasty were enrolled. Postoperatively the warfarin dose was adjusted daily to maintain the international normalized ratio between 1.8 and 2.5. Eighty-six patients successfully completed the study protocol. INTERVENTION: Before they were discharged from hospital, patients were assessed for DVT by clinical examination, bilateral compression ultrasonography of the proximal venous system and bilateral contrast venography. RESULTS: DVT was found in 29 patients (34%; 95% confidence interval [CI] 24% to 45%), and 6 patients (7%; 95% CI 3% to 15%) had proximal DVT. DVT developed in 18 (40%) of 45 patients who underwent total knee arthroplasty and in 11 (27%) of 41 patients who underwent total hip arthroplasty. The sensitivity of compression ultrasonography for the diagnosis of proximal DVT was 83% (95% CI 36% to 99%) and the specificity was 98% (95% CI 91% to 99%). The positive predictive value of compression ultrasonography was 71%. In contrast, clinical examination for DVT had a sensitivity of 11% (95% CI 2% to 28%) and a positive predictive value of 25%. CONCLUSIONS: DVT is a common complication after total hip or knee arthroplasty. Compression ultrasonography appears to be a relatively accurate noninvasive test for diagnosing postoperative proximal DVT. In contrast, clinical examination is a very insensitive test. Whether routine use of screening compression ultrasonography will reduce the morbidity of venous thromboembolism after joint arthroplasty requires confirmation in a prospective trial involving long-term follow-up of patients.

Foot problems in middle-aged patients: keeping active people up to speed.

Most of the common foot problems that bother active middle-aged people are self-limiting and easily treated if detected early. Reviewed here are the causes, symptoms, diagnosis, and treatment of hallux valgus and rigidus, lesser-toe deformities, corns, Morton's neuroma, metatarsal stress fractures, plantar fasciitis, posterior tibialis tenosynovitis and rupture, acquired pes planus, tarsal tunnel syndrome, and foot problems related to rheumatoid arthritis and diabetes. In most cases, conservative treatment will enable patients to return to activity relatively quickly.

Rehabilitation of tendon injuries in sport.

Clinicians are faced with a growing number of athletes with injured tendons. Treatment of both acute and chronic injuries has proven to be quite complex. It is difficult to maintain the balance between resting the injured tendon and preventing atrophy of the surrounding muscles and joints. Questions also arise as to when the tendon should be strengthened and when the athlete is ready to return to full activity in sport. Through an awareness of the structural and mechanical properties of the tendon, an exercise programme for the rehabilitation of tendon injuries has been developed. It is recommended that this programme be used in combination with ice and other physical modalities. This approach will resolve most tendon injuries within 6 weeks of its implementation. The use of anti-inflammatory medications and surgery can only be recommended in select situations where more conservative measures are inadequate.

Ultrasonographic screening before hospital discharge for deep venous thrombosis after arthroplasty: the post-arthroplasty screening study. A randomized, controlled trial.

BACKGROUND: The clinical significance of asymptomatic deep venous thrombosis that develops after joint arthroplasty and the value of screening tests to detect thrombi are uncertain. OBJECTIVES: To determine 1) the rate of symptomatic deep venous thrombosis or pulmonary embolism occurring after hospitalization for joint arthroplasty and 2) the value of screening compression ultrasonography. DESIGN: Double-blind, randomized, controlled trial. SETTING: Tertiary care hospital. PATIENTS: 1024 patients undergoing elective total hip or knee arthroplasty who received warfarin prophylaxis. INTERVENTION: Patients were randomly assigned to undergo either bilateral compression ultrasonography or a sham procedure before hospital discharge. Patients with a diagnosis of asymptomatic deep venous thrombosis were treated after discharge with standard anticoagulant therapy; other patients had warfarin therapy discontinued at discharge. All patients were followed for 90 days. RESULTS: In the screening group, asymptomatic proximal deep venous thrombosis was detected in 13 of 518 patients (2.5%). Another 4 patients subsequently developed symptomatic proximal deep venous thrombosis, and 1 patient treated for asymptomatic deep venous thrombosis developed major bleeding, for a total outcome event rate of 1.0% (5 of 518 patients). In the placebo group, 3 patients developed symptomatic proximal deep venous thrombosis and 2 had nonfatal pulmonary embolism, for a total event rate of 1.0% (5 of 506 patients) (difference, 0 percentage points [95% CI, -1.2 to 1.2 percentage points]). CONCLUSIONS: In patients undergoing total hip or knee arthroplasty, the use of warfarin prophylaxis during hospitalization results in a very low rate of symptomatic deep venous thrombosis or pulmonary embolism after hospital discharge. The use of screening compression ultrasonography at hospital discharge does not seem to be justified in this setting.

Lower leg, foot, and ankle injuries in young athletes.

Most injuries to the young athlete do have a benign natural course-complete resolution of the difficulty without sequelae. In order to develop a contemporary program of management of the more serious disorders in this active population, the practitioner must be certain to carefully analyze the injury and initiate a rapid course of action. A fracture of the tibia must be reduced, held aligned, and then rehabilitated. A compartment syndrome commonly demands early fasciotomy; the young athlete and his or her parents warrant a sensitive understanding from physicians to quell the anxiety that is paramount to all of these disorders.

Shoulder arthroscopy and nerve injury: pitfalls and prevention.

Shoulder arthroscopy has become a very useful diagnostic and therapeutic modality. Unfortunately, like many other invasive procedures it can have complications. One of the most worrisome complications, for both the patient and surgeon, is that of nerve injury. Nerve injury during shoulder arthroscopy is often a transient phenomenon although a more severe injury has been documented. We review much of the literature on this subject and discuss some of the many pitfalls and preventative strategies that have been reported.

Lower leg, foot, and ankle injuries in young athletes.

Most injuries to the young athlete do have a benign natural course--complete resolution of the difficulty without sequelae. In order to develop a contemporary program of management of the more serious disorders in this active population, the practitioner must be certain to carefully analyze the injury and initiate a rapid course of action. A fracture of the tibia must be reduced, held aligned, and then rehabilitated. A compartment syndrome commonly demands early fasciotomy; the young athlete and his or her parents warrant a sensitive understanding from physicians to quell the anxiety that is paramount to all of these disorders.