Comparison of total hip arthroplasty surgical approaches by Statistical Parametric Mapping

A prospective randomised comparison of earlier function after total hip arthroplasty with a mini posterior approach or supercapsular percutaneously-assisted total hip approach: a gait analysis study

BACKGROUND

The supercapsular percutaneously-assisted total hip (SuperPATH) approach is a muscle sparing surgical technique for total hip arthroplasty (THA). The literature reports good clinical and functional results of the SuperPATH technique in the short term. We aimed to compare early outcomes and gait analysis of THA using the mini posterior approach (MPA) and supercapsular percutaneously-assisted total hip (SuperPATH) approach.

METHODS

44 patients who underwent THA, were randomly allocated to either MPA or SuperPATH. The data were then collected prospectively (preoperatively and postoperatively at 6 weeks). Plain anteroposterior radiographs of the pelvis and instrumental gait analysis were obtained. The visual analogue scale (VAS), Harris Hip Score (HHS) and Hip disability and Osteoarthritis Outcome Scores (HOOS) were used to assess functional and clinical outcomes.

RESULTS

No significant difference was found in patients' surgical outcomes. Patients in the SuperPATH group had less pain according to the VAS score at follow-up than the MPA group (p < 0.01). There was also a significant improvement in HHS and HOOS scores for all patients (p < 0.001) with the SuperPATH group showing superior changes. The comparison of mean differences in gait velocity between preoperative and 6 weeks postoperative result, revealed improvement in the SuperPATH group over the MPA group (p = 0.06). Limping was more persistent in the MPA group. Kinematic parameters demonstrated improved hip joint excursion slightly higher in the MPA group. There was no significant improvement in kinetic and kinematic parameters at different walking moments for all patients at 6 weeks compared to preoperative gait patterns.

CONCLUSIONS

SuperPATH and MPA both show excellent results. This study reveals that the SuperPATH technique was associated with lower postoperative pain levels, and higher physical function and quality of life. Improved functional outcomes allowed earlier postoperative rehabilitation and faster recovery. Specific improvement in gait patterns were identified with nonsignificant differences between the 2 approaches at 6 weeks follow-up.

Similar kinematic patterns between revision total stabilized (TS) and primary posterior stabilized (PS) knee prostheses: a prospective case-controlled study with gait assessment

PURPOSE

There are increased surgical considerations when revising total knee arthroplasty (TKA) in active patients. Few studies have assessed if a semi-constrained [Total Stabilized (TS)] prostheses has similar knee biomechanics to a primary posterior stabilized (PS) prosthesis. The aim was to compare the gait parameters in patients with PS or TS TKA and normal controls.

METHODS

32 patients with TKA were prospectively included with either a primary PS (n = 15) or a revision TS (n = 17) prosthesis. Gait analysis was performed at 6 months postoperatively for each patient, with an optoelectronic knee assessment device (KneeKG®) assessing the displacement of the tibia relative to the femur during the different gait phases (flexion/extension, anterior/posterior translation, adduction/abduction, internal/external rotation). A control group (n = 12) of healthy knees was compared with the TKA groups.

RESULTS

There were no significant kinematic differences between PS and TS groups. The maximum knee flexion during gait was 53° ± 8.1° in the PS group vs 52° ± 8.7° in the TS group. The antero-posterior translation was similar in both group (2.3 ± 0.5 mm vs 2.6 ± 0.9 mm, respectively). Peak varus angle during loading and swing phase was slightly higher in the TS group (2.7° ± 0.7° and 5.2° ± 0.9°) than in the PS group (2.9° ± 0.6° and 5.6° ± 1.2°), without significant difference. The ranges in internal/external rotation were similar between PS and TS TKA (3.7° ± 0.5° vs 3.3° ± 0.6°, respectively). Both designs approached closely the normal gait patterns of the control group except in the frontal plane.

CONCLUSION

Single radius TS TKA has gait parameters similar to single radius PS TKA. Use of a single radius TS TKA in revision TKA is not detrimental to a patient's gait pattern. Both designs approached closely the normal gait patterns of the control group.

LEVEL OF EVIDENCE

Prospective, case-control study; Level III.

Intersegmental Coordination in Patients With Total Knee Arthroplasty During Walking

Precise identification of deficient intersegmental coordination patterns and functional limitations is conducive to the evaluation of surgical outcomes after total knee arthroplasty (TKA) and the design of optimal personalized rehabilitation protocols. However, it is still not clear how and when intersegmental coordination patterns change during walking, and what functional limitations are in patients with TKA. This study was designed to investigate lower limb intersegmental coordination patterns in patients with knee osteoarthritis before and after TKA and identify how intersegmental coordination of patients is altered during walking before and after TKA. It was hypothesized that 6-month after TKA, intersegmental coordination patterns of patients are improved compared with that before TKA, but still do not recover to the level of healthy subjects. Gait analysis was performed on 36 patients before and 6-month after TKA and on 34 healthy subjects. Continuous relative phase (CRP) derived from the angle-velocity phase portrait was used to measure the coordination between interacting segments throughout the gait cycle. Thigh-shank CRP and shank-foot CRP were calculated for each subject. Statistical parametric mapping (SPM), a one-dimensional analysis of the entire gait cycle curve, was performed directly to determine which periods of the gait cycle were different in patients and healthy subjects. Six-month after TKA, thigh-shank CRP was significantly higher during 5–12% of the gait cycle (p = 0.041) and lower during 44–95% of the gait cycle (p < 0.001) compared with healthy subjects, and was significantly higher during 62–91% of the gait cycle (p = 0.002) compared with pre-operation. Shank-foot CRP was significantly lower during 0–28% of the gait cycle (p < 0.001) and higher during 58–94% of the gait cycle (p < 0.001) compared with healthy subjects, and was significantly lower during 3–18% of the gait cycle (p = 0.005) compared with pre-operation. This study found that patients exhibited altered intersegmental coordination during the loading response and swing phase both before and after TKA. Six-month after TKA, the thigh-shank coordination was partially improved compared with pre-operation, but still did not recover to the level of healthy subjects, while there was no improvement in the shank-foot coordination pattern after TKA compared with pre-operation. CRP combined with SPM methods can provide insights into the evaluation of surgical outcomes and the design of rehabilitation strategy.

Fear-avoidance beliefs are associated with reduced lumbar spine flexion during object lifting in pain-free adults

ABSTRACT

There is a long-held belief that physical activities such as lifting with a flexed spine is generally harmful for the back and can cause low back pain (LBP), potentially reinforcing fear-avoidance beliefs underlying pain-related fear. In patients with chronic LBP, pain-related fear has been shown to be associated with reduced lumbar range of motion during lifting, suggesting a protective response to pain. However, despite short-term beneficial effects for tissue health, recent evidence suggests that maintaining a protective trunk movement strategy may also pose a risk for (persistent) LBP due to possible pronociceptive consequences of altered spinal motion, potentially leading to increased loading on lumbar tissues. Yet, it is unknown if similar protective movement strategies already exist in pain-free individuals, which would yield potential insights into the role of fear-avoidance beliefs in motor behavior in the absence of pain. Therefore, the aim of this study is to test whether fear-avoidance beliefs influence spinal motion during lifting in a healthy cohort of pain-free adults without a history of chronic pain. The study subjects (N = 57) filled out several pain-related fear questionnaires and were asked to perform a lifting task (5kg-box). High-resolution spinal kinematics were assessed using an optical motion capturing system. Time-sensitive analyses were performed based on statistical parametric mapping. The results demonstrated time-specific and negative relationships between self-report measures of pain-related fear and lumbar spine flexion angles during lifting, indicating potential unfavorable interactions between psychological factors and spinal motion during lifting in pain-free subjects.

Sample size estimation for biomechanical waveforms: Current practice, recommendations and a comparison to discrete power analysis

Testing a prediction is fundamental to scientific experiments. Where biomechanical experiments involve analysis of 1-Dimensional (waveform) data, sample size estimation should consider both 1D variance and hypothesised 1D effects. This study exemplifies 1D sample size estimation using typical biomechanical signals and contrasts this with 0D (discrete) power analysis. For context, biomechanics papers from 2018 and 2019 were reviewed to characterise current practice. Sample size estimation occurred in approximately 4% of 653 papers and reporting practice was mixed. To estimate sample sizes, common biomechanical signals were sourced from the literature and 1D effects were generated artificially using the open-source power1d software. Smooth Gaussian noise was added to the modelled 1D effect to numerically estimate the sample size required. Sample sizes estimated using 1D power procedures varied according to the characteristics of the dataset, requiring only small-to-moderate sample sizes of approximately 5-40 to achieve target powers of 0.8 for reported 1D effects, but were always larger than 0D sample sizes (from N + 1 to >N + 20). The importance of a priori sample size estimation is highlighted and recommendations are provided to improve the consistency of reporting. This study should enable researchers to construct 1D biomechanical effects to address adequately powered, hypothesis-driven, predictive research questions.

Non-amputated limb muscle coordination of unilateral transfemoral amputees

Unilateral transfemoral amputees rely heavily on non-amputated limb muscles to regulate the prosthetic gait. In this study, we compared the non-amputated limb muscle coordination of eight unilateral transfemoral amputees to eight able-bodied controls. Inverse dynamics approach was conducted via a musculoskeletal model to obtain lower limb joint moments and muscle forces. In addition to the muscle forces at the instants of peak joint moments and the maximum muscle forces, the peak joint moments of the lower limbs were also investigated. The results showed that there were significant differences of muscle forces between the non-amputated limbs and the controls at the instant of peak hip extension moment, although the peak hip extension moments themselves were not significantly different between the two groups. The non-amputated limbs had significantly smaller peak hip flexion moment and peak knee extension moment, with significant differences between the muscle forces of non-amputated limbs and controls at the two instants. There was no significant difference between the muscle forces of the non-amputated limbs and controls at the peak knee flexion moment instant, despite the fact that the non-amputated limbs had significantly higher peak knee flexion moments. In addition, the non-amputated limbs had significantly smaller maximum muscle forces than the controls. These results demonstrate that amputees modify their muscle coordination to adapt to the specific joint requirements of the prosthetic gait. Our findings suggest the possibility of non-amputated limb muscle atrophy due to the decrease in the peak muscle forces during walking.

Alteration of movement patterns in low back pain assessed by Statistical Parametric Mapping

Changes in movement pattern in low back pain (LBP) groups have been analysed by reporting predefined discrete variables. However, this approach does not consider the full kinematic data waveform and its dynamic information, potentially exposing the analysis to bias. Statistical Parametric Mapping (SPM) has been introduced and applied to 1 dimensional (D) kinematic variables allowing the assessment of data over time. The aims of this study were to assess differences in 3D kinematics patterns in people with and without LBP during functional tasks by using SPM and to investigate if SPM analysis was consistent with standard 3D range of motion (RoM) assessments. 3D joints kinematics of the spine and lower limbs were compared between 20 healthy controls and 20 participants with non-specific LBP during walking, sit-to-stand and lifting. SPM analysis showed significant differences in the 3Dkinematics of the lower thoracic segment, upper and lower lumbar segment and knee joint during walking and lifting mostly observed at the beginning and/or towards the end of the tasks. ROMs differed between groups in the lower thoracic segment (walking/sit-to-stand), upper and lower lumbar segments (walking/sit-to-stand/lifting), hip and knee (sit-to-stand/lifting). Based on these results, the two approaches can yield different data interpretations. SPM analysis allows the identification of differences in movement that occur over time. This adds value to LBP movement analysis as it allows an understanding of the LBP strategies adopted during motion that may not be conveyed by simple discrete parameters such as ROMs.

A New Method of Evaluating the Symmetry of Movement Used to Assess the Gait of Patients after Unilateral Total Hip Replacement

Purpose

We propose a new concept of symmetry, the symmetry function, as a continuous function of the percentage of differences between sides of body movement and normalised throughout the whole range of motion. The method is used to assess the dynamical symmetry of gait of patients after unilateral total hip replacement (asymmetric group) and healthy people (symmetric group) and also to reveal discrepancies between normal and abnormal movement patterns.

Methods

The gait of twelve male patients (49.7 ± 2.8 y), six weeks after unilateral total hip replacement (uTHR), was analysed against the gait of thirteen healthy men (36.1 ± 3.1 y). The speed of healthy men was matched to the speed of the patients. Comparison of the affected limb in uTHR patients with the healthy limb of able-bodied men was carried out on the basis of the highest symmetry values in the sagittal plane.

Results

In uTHR patients, the symmetry function provides information on the symmetry of movements in the whole range of motion in contrast to symmetry indices which are calculated for selected parameters or peak values. Research revealed average asymmetric discrepancies for pelvic tilt up to 250% for the entire gait cycle with a peak of approx. 400% at the end of the loading response and terminal swing phases. Asymmetry of gait observed in other joints was below 200% of the mean range of motion.

Conclusions

Regions of the greatest asymmetry in pathological movements are usually different from the region of the greatest range of motion. Therefore, it is insufficient to measure symmetry only for selected regions during motion. The symmetry function is a simple method which can complement other robust methods in time series data evaluation and interpretation.

Kinematic profiles during activities of daily living in adults with traumatic brachial plexus injuries

BACKGROUND

Injuries to the brachial plexus leave individuals with lasting effects in upper extremity motor function, even with successful surgical restoration of elbow flexion. Quantitatively describing independent patient function during activities of daily living utilizing motion analysis could aid in prioritization of secondary surgical targets, as well as serve as an outcome measure. This study explored the upper extremity kinematic profiles during activities of daily living in adults with brachial plexus injury.

METHODS

Eight adult participants (4 subjects with brachial plexus injury, 4 healthy controls) completed activities of daily living during one motion capture setting. Trunk, shoulder, and elbow joint minima, maxima, and range of motion were calculated and compared between groups. Kinematic profiles over a motion cycle were compared between groups using statistical parametric mapping.

FINDINGS

Subjects with brachial plexus injuries had significantly greater trunk range of motion during feeding and dressing tasks compared to control subjects. This compensatory trunk motion was accompanied by limited shoulder external rotation demonstrated using conventional descriptors and statistical parametric mapping.

INTERPRETATION

Significant compensatory trunk motion is required to complete select activities of daily living in subjects with brachial plexus injury. Additionally, restoration of shoulder external rotation would be a beneficial secondary target of surgical restoration of motor function. These aspects should be considered in treatment planning, as they could impact patient outcomes. Combining conventional descriptors of patient motion (e.g. joint minima, maxima, and range of motion) with statistical parametric mapping can provide a rich description of patient compensations and limitations.