Clinical Gait Evaluation of Patients with Lumbar Spine Stenosis.

OBJECTIVE: The third generation Intelligent Device for Energy Expenditure and Activity (IDEEA3, MiniSun, CA) has been developed for clinical gait evaluation, and this study was designed to evaluate the accuracy and reliability of IDEEA3 for the gait measurement of lumbar spinal stenosis (LSS) patients. METHODS: Twelve healthy volunteers were recruited to compare gait cycle, cadence, step length, velocity, and number of steps between a motion analysis system and a high-speed video camera. Twenty hospitalized LSS patients were recruited for the comparison of the five parameters between the IDEEA3 and GoPro camera. Paired t-test, intraclass correlation coefficient, concordance correlation coefficient, and Bland-Altman plots were used for the data analysis. RESULTS: The ratios of GoPro camera results to motion analysis system results, and the ratios of IDEEA3 results to GoPro camera results were all around 1.00. All P-values of paired t-tests for gait cycle, cadence, step length, and velocity were greater than 0.05, while all the ICC and CCC results were above 0.950 with P < 0.001. CONCLUSIONS: The measurements for gait cycle, cadence, step length, velocity, and number of steps with the GoPro camera are highly consistent with the measurements with the motion analysis system. The measurements for IDEEA3 are consistent with those for the GoPro camera. IDEEA3 can be effectively used in the gait measurement of LSS patients.

Clinical gait evaluation of patients with knee osteoarthritis.

Knee osteoarthritis (KOA) is the most common osteoarthritis in lower limbs, and gait measurement is important to evaluate walking function of KOA patients before and after treatment. The third generation Intelligent Device for Energy Expenditure and Activity (IDEEA3) is a portable gait analysis system to evaluate gaits. This study is to evaluate the accuracy and reliability of IDEEA3 for gait measurement of KOA patients. Meanwhile, gait differences between KOA patients and healthy subjects are examined. Twelve healthy volunteers were recruited for measurement comparison of gait cycle (GC), cadence, step length, velocity and step counts between a motion analysis system and a high-speed camera (GoPro Hero3). Twenty-three KOA patients were recruited for measurement comparison of former five parameters between GoPro Hero3 and IDEEA3. Paired t-test, Concordance Correlation Coefficient (CCC) and Intraclass Correlation Coefficient (ICC) were used for data analysis. All p-values of paired t-tests for GC, cadence, step length and velocity were greater than 0.05 while all CCC and ICC results were above 0.95. The measurements of GC, cadence, step length, velocity and step counts by motion analysis system are highly consistent with the measurements by GoPro Hero3. The measurements of former parameters by GoPro Hero3 are not statistically different from the measurements by IDEEA3. IDEEA3 can be effectively used for the measurement of GC, cadence, step length, velocity and step counts in KOA patients. The KOA patients walk with longer GC, lower cadence, shorter step length and slower speed compared with healthy subjects in natural speed with flat shoes.

Gait phase varies over velocities.

We sought to characterize the percent (PT) of the phases of a gait cycle (GC) as velocity changes to establish norms for pathological gait characteristics with higher resolution technology. Ninety five healthy subjects (49 males and 46 females with age 34.9 ± 11.8 yrs, body weight 64.0 ± 11.7 kg and BMI 23.5 ± 3.6) were enrolled and walked comfortably on a 10-m walkway at self-selected slower, normal, and faster velocities. Walking was recorded with a high speed camera (250 frames per second) and the eight phases of a GC were determined by examination of individual frames for each subject. The correlation coefficients between the mean PT of the phases of the three velocities gaits and PT defined by previous publications were all greater than 0.99. The correlation coefficient between velocity and PT of gait phases is -0.83 for loading response (LR), -0.75 for mid stance (MSt), and -0.84 for pre-swing (PSw). While the PT of the phases of three velocities from this study are highly correlated with PT described by Dr. Jacquenlin Perry decades ago, actual PT of each phase varied amongst these individuals with the largest coefficient variation of 24.31% for IC with slower velocity. From slower to faster walk, the mean PT of MSt diminished from 35.30% to 25.33%. High resolution recording revealed ambiguity of some gait phase definitions, and these data may benefit GC characterization of normal and pathological gait in clinical practice. The study results indicate that one should consider individual variations and walking velocity when evaluating gaits of subjects using standard gait phase classification.

Dynamic electromyography after cruciate-retaining total knee arthroplasty revealed a threefold quadriceps demand compared with the contralateral normal knee.

Quadriceps functional impairment accounts for a considerable amount of morbidity after knee replacement. Cruciate-retaining total knee arthroplasty (CR-TKA) may predispose to increased quadriceps demand. We compared bilateral relative quadriceps effort in seven patients with successful unilateral CR-TKA at least 2years after surgery. Dynamic electromyography (EMG) recorded quadriceps activity during walking recorded simultaneously with gait analysis using IDEEA. There was greater EMG activity for the operated knees, both in amplitude (43.08±26.47 vs. 16.02±5.38, P=.0355), and the area under the curve (7231.1±3869.8 vs. 2547.3±1007.9, P=.0267). The onset and duration of muscle activity were similar for both knees (P=.74). CR-TKA demonstrated threefold EMG activity and muscle effort during normal walking. The study suggested that quadriceps functional deficiency is associated with CR-TKA.

Fatal cerebral emboli in the absence of a cardiac arterial-venous shunt: case report.

Cerebral embolism in patients undergoing total joint arthroplasty has an incidence rate of 0.5%. In those cases where cerebral emboli were confirmed, a venous-to-arterial circulation shunt, most commonly a patent foramen ovale, was identified. We report a case of severe cerebral fat emboli during cementless total hip arthroplasty in the absence of an intracardiac defect.

Durability of implant fixation after less-invasive total hip arthroplasty.

Less-invasive techniques for total hip arthroplasty (THA) have sparked an increased interest among orthopedic surgeons and patients. There has been concern regarding decreased surgical exposure and compromise in prosthesis durability. We present the first long-term outcome of THA performed via the mini-incision posterior approach to show the durability of implant fixation. We compare the clinical and radiographic findings with previously published findings of authors using the same femoral implant and standard surgical techniques over a similar follow-up period. Ninety implants were followed for 10 to 13 years. Clinical evaluation revealed a Harris Hip Score of 92.3. Radiographic evaluation revealed proximal bone atrophy in 57% and lucent lines in 14% of femurs and 11% of cups. Osteolysis was noted in 10% and was associated with polyethylene wear. There were no cases of aseptic stem loosening. Eight polyethylene inserts were revised for wear. These 10-year minimum follow-up findings are consistently comparable with previously published studies using the same implant and larger surgical approaches followed for a similar period. Mini-incision THA technique did not compromise the long-term clinical and radiographic findings when compared with conventional techniques.

Dual-energy x-ray absorptiometry measurement and accuracy of bone mineral after unilateral total hip arthroplasty.

The standard technique for monitoring bone mineral in hip arthroplasty has been dual-energy x-ray absorptiometry (DEXA). The accuracy of DEXA in the cortical bone adjacent to femoral components has not been established. This study evaluated bone mineral in the cortical bone adjacent to the femoral component comparing DEXA and ashing. Seven pairs of human femora from postmortem donors with unilateral hip implants were examined. Twenty-eight ashed core specimens from both the medial and lateral sides were taken. Cortical bone loss was seen to be greater in the proximal and medial regions of the implanted femora. Dual-energy x-ray absorptiometry failed to show an acceptable level of accuracy compared with ash data (r = 0.56; P = .002). It did show relative patterns of bone loss. Bone loss was consistent with implant-induced stress shielding.

Ambulatory activities maintain cortical bone after total hip arthroplasty.

Because periprosthetic bone loss impacts revision total hip arthroplasties and subsequent patient recovery, it is important to understand the consequences of stress shielding. We characterized bone loss attributed to stress shielding by investigating the influence of patient activity and demographics on reductions in cortical bone cross-sectional area, bone mineral density, and bone mineral content. Cortical bone shape, bone mineral content, and bone mineral density were measured in implanted and contralateral nonimplanted cadaveric femurs. Geometric measurements of transverse cross sections were measured with imaging software. Dual energy x-ray absorptiometry measured bone mineral content and bone mineral density. Patient activity was estimated by the mechanical usage score. The mechanical usage score was comprised of the ambulatory components of the Harris hip score. Regression analysis revealed a lower mechanical usage score and patient weight correlated with greater bone loss. Age, implant size, and time in situ did not correlate to bone loss. The implanted femurs were reduced in cross-sectional area and rigidity, and expanded endosteally and periosteally. Principal axis location did not change. Bone loss was more likely to occur uniformly than to change cortical bone distribution. Bone loss was minimized in patients with higher activity levels.

Assessment of human locomotion by using an insole measurement system and artificial neural networks.

A new method for measuring and characterizing free-living human locomotion is presented. A portable device was developed to objectively record and measure foot-ground contact information in every step for up to 24h. An artificial neural network (ANN) was developed to identify the type and intensity of locomotion. Forty subjects participated in the study. The subjects performed level walking, running, ascending and descending stairs at slow, normal and fast speeds determined by each subject, respectively. The device correctly identified walking, running, ascending and descending stairs (accuracy 98.78%, 98.33%, 97.33%, and 97.29% respectively) among different types of activities. It was also able to determine the speed of walking and running. The correlation between actual speed and estimated speed is 0.98, p< 0.0001. The average error of walking and running speed estimation is -0.050+/-0.747 km/h (mean +/- standard deviation). The study has shown the measurement of duration, frequency, type, and intensity of locomotion highly accurate using the new device and an ANN. It provides an alternative tool to the use of a gait lab to quantitatively study locomotion with high accuracy via a small, light and portable device, and to do so under free-living conditions for the clinical applications.

Bilateral pathologic fractures of the hip and acetabulum treated with cementless total hip arthroplasty.

Pathologic fractures from metastatic cancer pose formidable challenges to the orthopaedic surgeon technically and in terms of surgical decision making with regards to patient quality of life. We present the case of a 47-year-old woman with simultaneous bilateral pathologic femoral neck and acetabulum fractures and severe pulmonary shunt, who was treated successfully with cementless femoral and acetabular implants.

Results of a tapered cementless femoral stem implanted in varus.

Varus placement of the femoral component in total hip arthroplasty has been associated with poor outcomes. The purpose of this study was to examine results of total hip arthroplasty with varus alignment of a tapered titanium femoral prosthesis (Alloclassic; Sulzer, Zurich, Switzerland) at a minimum 5-year follow-up. Of a consecutive series of 585 patients, 23 met the inclusion criteria. Harris hip scores averaged 97, and all implants were clinically and radiographically stable at the most recent follow-up. In this series of patients, varus alignment of the prosthesis did not have an adverse effect on outcome. Although malalignment of the femoral prosthesis may compromise the results of some designs, the Alloclassic prosthesis has proved to be reliable and forgiving despite varus malalignment at 5 to 11 years' follow-up.