Hip Osteoarthritis Patients Demonstrated Marked Dynamic Changes and Variability in Pelvic Tilt, Obliquity, and Rotation: A Comparative, Gait-Analysis Study.

INTRODUCTION: Changes in pelvic position has been shown to affect acetabular coverage of the femoral head in total hip arthroplasty (THA) and may contribute to complications such as impingement, dislocation, or early wear. Understanding the kinematic changes of these positions during functional activities may help surgeons reach a consensus regarding stable hip mechanics and ideal implant positioning in THA. Therefore, in this study, we aimed to evaluate the following in patients who had unilateral hip OA: 1) dynamic changes; and 2) variability; in the following pelvic position parameters: A) tilt; B) obliquity; and C) rotation standing position to walking. This same data was also collected from a control cohort of normal subjects with non-arthritic hip joints. Data from both cohorts were then compared. MATERIALS AND METHODS: This study analyzed 50 patients who had unilateral osteoarthritis of the hip. There were 27 men and 23 women who had a mean age of 59 years, a mean height of 173 cm (range, 152 to 200 cm), a mean weight of 84 kg (range, 31.5 to 125 kg), and a mean body mass index (BMI) of 28 kg/m2 [range, 13 to 43 kg/m2). In addition, a cohort of 19 healthy subjects with matching demographics (11 men and 9 women, mean age; 64, mean height; 168 cm, mean weight; 88 kg, mean BMI; 30 kg/m2) served as a control group. Joint marker sets were used for analysis and specific markers were used to assess pelvic position of the participants. In each cohort, mean pelvic tilt, obliquity, and rotation values in standing position, as well as mean minimum and maximum values in walking position were collected and compared. Dynamic change from standing to walking was calculated in both cohorts and then compared. Variability was demonstrated by comparing a graphic representation of individual values from both cohorts. RESULTS: In hip OA patients, wide dynamic changes were demonstrated in pelvic tilt, obliquity, and rotation when going from a standing to a walking position (pelvic tilt; mean standing +8°, [range, -5° to +32°], walking range -13.5° to +33°, obliquity; mean standing +0.4°, [range, -8° to 7°], walking range -14° to +10°, rotation; mean standing -1.5° [range, -16 to +10°], and walking range -28° to +13°). In the non-arthritic cohort, narrower ranges of dynamic changes were recorded (pelvic tilt; mean standing +7°, [range, +4.35° to +9.81°], walking range +4.35° to +9.81°, obliquity; mean standing +0.66° , [range, -0.35° to 1.67°], walking range [-2.8° to 5.1°], rotation; standing mean +0.5° [range, -1.16° to +2.16°], and walking range [-6.8° to +5.1°]). When both cohorts were compared, the hip OA cohort had a three- to four-folds increase in dynamic change relative to the non-arthritic group, and in pelvic tilt, obliquity, and rotation (pelvic tilt; 38.5° vs. 9.3°, obliquity; 23.6° vs. 7.24°, rotation; 39.5° vs. 11.4). In addition, marked variability in pelvic position was also demonstrated when walking ranges of all three parameters for hip OA patients were compared to the non-arthritic subjects. CONCLUSION: This study utilized a novel and innovative approach to analyze the dynamic changes and variability in pelvic position parameters in patients with hip OA in comparison to non-arthritic matching subjects. Hip OA patients showed marked changes in pelvic tilt, obliquity, and rotation when going from standing to walking. Non-arthritic subjects exhibited much less noticeable changes in all three parameters. When dynamic changes in both cohorts were compared, hip OA patients had a three- to four-folds increase relative to the non-arthritic group with marked variability in walking ranges. These findings may have implications on the acetabular spatial orientation and highlight the need for individual planning when undertaking THA to account for the dynamic changes in pelvic position parameters during functional activities.

Gait Using Pneumatic Brace for End-Stage Knee Osteoarthritis.

More than 20 million individuals in the United States are affected by knee osteoarthritis (OA), which can lead to altered biomechanics and excessive joint loading. The use of an unloader pneumatic brace with extension assist has been proposed as a nonoperative treatment modality that may improve gait mechanics and correct knee malalignment. We assessed the following parameters in patients who have knee OA treated with and without a brace: (1) changes in temporospatial parameters in gait; (2) knee range of motion, knee extension at heel strike, and foot placement; (3) knee joint moments and impulse; and (4) changes in dynamic stiffness and rate of change of knee flexion during midstance to terminal stance. This 2:1 prospective, randomized, single-blinded trial evaluated 36 patients (24 brace and 12 matching). OA knee patients were randomized to receive either a pneumatic unloader brace or a standard nonoperative treatment regimen as the matching cohort for a 3-month period. They underwent evaluation of gait parameters using a three-dimensional gait analysis system at their initial appointment and at 3 months follow-up. All the testing, pre- and postbracing were performed without wearing the brace to examine for retained effects. Treatment with the brace led to significant improvements versus standard treatment in various gait parameters. Patients in the brace group had improvements in walking speed, knee extension at heel strike, total range of motion, knee joint forces, and rate of knee flexion from midstance to terminal stance when compared with the matching cohort. Knee OA patients who used a pneumatic unloader brace for 3 months for at least 3 hours per day had significant improvements various gait parameters when compared with a standard nonoperative therapy cohort. Braced patients demonstrated gait-modifying affects when not wearing the brace. These results are encouraging and suggest that this device represents a promising treatment modality for knee OA that may improve gait, knee pain, and strength in knee OA patients.

Unloader Bracing for Knee Osteoarthritis: A Pilot Study of Gait and Function.

Knee osteoarthritis (OA) is increasing in the United States, and some have proposed the use of unloader bracing as an adjunct to current standard treatments. Our purpose was to evaluate outcomes of this brace for the treatment of knee osteoarthritis compared with standard non-operative treatment. Specifically, we evaluated: (1) pain relief, (2) objective functional improvement, (3) subjective functional improvement, (4) quality of life, (5) isokinetic quadriceps muscle strength, and (6) gait changes. A prospective, randomized, study was performed on 18 patients who had Kellgren-Lawrence grade 1 and 2 osteoarthritis. Patients were randomized to receive either standard treatment or an unloader brace. End points evaluated included: functional tests, Knee Society Score, Short Form 36 (SF-36) health survey, Visual Analog Scale (VAS) for pain, Lower Extremity Functional Scale, isokinetic quadriceps and hamstring muscle strength, and 3-dimensional gait analysis. There were no differences between cohorts in evaluation of pain (VAS), objective functional tests, subjective functional outcomes (Knee Society Scores and LEFS), quality of life assessment with SF-36, isokinetic quadriceps and hamstring muscle strength, and gait parameters. The use of unloader brace demonstrated similar improvements compared with standard treatments for knee osteoarthritis, and we believe that it can be a beneficial or equivalent adjunct to continuum of care for the treatment for knee osteoarthritis.

Strength and Functional Improvement Using Pneumatic Brace with Extension Assist for End-Stage Knee Osteoarthritis: A Prospective, Randomized trial.

Pneumatic unloader bracing with extension assists have been proposed as a non-operative modality that may delay the need for knee surgery by reducing pain and improving function. This prospective, randomized trial evaluated 52 patients who had knee osteoarthritis for changes in: (1) muscle strength; (2) objective functional improvements; (3); subjective functional improvements; (4) pain; (5) quality of life; and (6) conversion to total knee arthroplasty (TKA) compared to standard of care. Patient outcomes were evaluated at a minimum 3 months. Braced patient's demonstrated significant improvements in muscle strength, several functional tests, and patient reported outcomes when compared to the matched cohort. These results are encouraging and suggest that this device may represent a promising alternative to standard treatment methods for knee osteoarthritis.

Gait and clinical improvements with a novel knee brace for knee OA.

INTRODUCTION: Knee osteoarthritis causes debilitating pain, and results in characteristic gait changes. Some authors believe that a system of neuromuscular retraining may improve these parameters. We therefore evaluated a novel brace that combines pneumatic joint unloading and active swing-assist to assess: (1) differences in pain levels or medication usage; (2) reductions in additional interventions; (3) changes in quadriceps muscle strength; and (4) improvements in specific gait measurements after 3 months. PATIENTS AND METHODS: A prospective pilot series of 10 knee osteoarthritis patients who had exhausted other nonoperative treatment measures were enrolled. These patients were compared with the previous 15 knee osteoarthritis patients who met similar criteria, but were not braced. Quadriceps muscle strength was measured, as were pain levels, and additional interventions such as injections or total knee arthroplasty procedures. Gait parameters measured included: walking speed, total range-of-motion, knee flexion at foot-strike, and knee adduction moment. RESULTS: All but one of the compliant patients reported a decrease of at least two pain points after 3 months of use. There was one additional intervention in the brace cohort versus a statistical increase of 10 in the nonbrace cohort. All patients who were compliant with the brace showed an increase in thigh girth measurements, compared with none in the nonbrace cohort. Braced patients experienced retained improvements in at least one gait parameter including improved walking speed, total range of motion, and improved knee-angle at heel strike. The mean improvement in knee adduction moment was a decrease of 0.2255 Nm/kg (range, 0.56 to 0.564 Nm/kg), showing a mean improvement of 48% (range, 16 to 76% of original peak moment). CONCLUSIONS: The use of a brace that has features including a combination of unloader characteristics along with active swing-assist, provided neuromuscular retraining benefits for patients who have knee osteoarthritis. In summary, although quite encouraging, future larger scale and prospective randomized studies need to assess the potential benefits of this brace for treating knee osteoarthritis. LEVEL OF EVIDENCE: Level II.

A comprehensive outcome comparison of surgical and Ponseti clubfoot treatments with reference to pediatric norms.

PURPOSE: Isolated congenital clubfoot can be treated either operatively (posteromedial release) or conservatively (Ponseti method). This study retrospectively compared mid-term outcomes after surgical and Ponseti treatments to a normal sample and used multiple evaluation techniques, such as detailed gait analysis and foot kinematics. METHODS: Twenty-six children with clubfoot treated surgically and 22 children with clubfoot treated with the Ponseti technique were evaluated retrospectively and compared to 34 children with normal feet. Comprehensive evaluation included a full gait analysis with multi-segment and single-segment foot kinematics, pedobarograph, physical examination, validated outcome questionnaires, and radiographic measurements. RESULTS: The Ponseti group had significantly better plantarflexion and dorsiflexion range of motion during gait and had greater push-off power. Residual varus was present in both treatment groups, but more so in the operative group. Gait analysis also showed that the operative group had residual in-toeing, which appeared well corrected in the Ponseti group. Pedobarograph results showed that the operative group had significantly increased varus and significantly decreased medial foot pressure. The physical examination demonstrated significantly greater stiffness in the operative group in dorsiflexion, plantarflexion, ankle inversion, and midfoot abduction and adduction. Surveys showed that the Ponseti group had significantly more normal pediatric outcome data collection instrument results, disease-specific indices, and Dimeglio scores. The radiographic results suggested greater equinus and cavus and increased foot internal rotation profile in the operative group compared with the Ponseti group. CONCLUSIONS: Ponseti treatment provides superior outcome to posteromedial release surgery, but residual deformity still persists.

Gait analysis of patients with resurfacing hip arthroplasty compared with hip osteoarthritis and standard total hip arthroplasty.

Patients with standard total hip arthroplasties may have reduced hip abduction and extension moments when compared with normal nonosteoarthritic hips. In comparison, patients after resurfacing total hip arthroplasty appear to have a near-normal gait. The authors evaluated temporal-spatial parameters, hip kinematics, and kinetics in hip resurfacing patients compared with patients with unilateral osteoarthritic hips and unilateral standard total hip arthroplasties. Patients with resurfacing walked faster (average 1.26 m/s) and were comparable with normals. There were no significant differences in hip abductor and extensor moments of patients with resurfacing compared with patients in the standard hip arthroplasty group. This study showed more normal hip kinematics and functionality in resurfacing hip arthroplasty, which may be due to the large femoral head.

Intra-subject repeatability of the three dimensional angular kinematics within the lumbo-pelvic-hip complex during running.

The intra-subject repeatability of measuring the three dimensional (3D) angular kinematics of the lumbo-pelvic-hip complex during running was evaluated. Spatio-temporal parameters were found to be repeatable. All angular kinematic parameters displayed high within-day repeatability despite numerous potential sources of variability in the data. Most angular kinematic parameters also displayed high between-day and overall repeatability, except for trunk flexion-extension, lumbar spine flexion-extension, pelvic anterior-posterior tilt, hip axial rotation and thigh axial rotation. These angular parameters were highly susceptible to marker reapplication errors that produced static daily offsets in the data. Overall, the results of this study suggest that the 3D angular kinematic patterns of the lumbo-pelvic-hip complex during running can be measured with sufficient repeatability to justify the implementation of the method as an evaluation tool in future investigations. However, caution must be exerted when interpreting the absolute magnitudes of trunk flexion-extension, lumbar spine flexion-extension, pelvic anterior-posterior tilt, hip axial rotation and thigh axial rotation, given the poor level of repeatability found for these measures.