Exploring pelvis and thigh movement and coordination patterns during walking in patients after total hip arthroplasty

BACKGROUND

Patients after total hip arthroplasty (THA) have altered hip kinematics compared to healthy controls, specifically hip extension and range of motion are lower. Exploring pelvis-thigh coordination patterns and coordination variability may help to elucidate why differences in hip kinematics are evident in patients following THA.

RESEARCH QUESTION

Do sagittal plane hip, pelvis and thigh kinematics, and pelvis-thigh movement coordination and coordination variability differ between patients following THA and healthy controls during walking?

METHODS

Sagittal plane hip, pelvis and thigh kinematics were collected using a three-dimensional motion capture system while 10 patients who had undergone THA and 10 controls walked at a self-selected pace. A modified vector coding technique was used to quantify pelvis-thigh coordination and coordination variability patterns. Peak hip, pelvis and thigh kinematics and ranges of motion, and movement coordination and coordination variability patterns were quantified and compared between groups.

RESULTS

Patients after THA have significantly (p ≤ .036; g ≥ 0.995) smaller peak hip extension and range of motion, and peak thigh anterior tilt and range of motion compared to controls. Additionally, patients following THA have significantly (p ≤ .037; g ≥ 0.646) more in-phase distally and less anti-phase distally dominated pelvis-thigh movement coordination patterns compared to controls.

SIGNIFICANCE

The smaller peak hip extension and range of motion displayed by patients following THA is due to smaller peak anterior tilt of the thigh, which in turn limits thigh range of motion. The lower sagittal plane thigh, and in turn hip, motion used by patients after THA may be due to increases in the in-phase coordination of pelvis-thigh motion patterns, which cause the pelvis and thigh to work as a singular functional unit.

Do patients with well-functioning total hip arthroplasty achieve typical sagittal plane hip kinematics? A proof of concept study

BACKGROUND

Total hip arthroplasty (THA) patients have been shown to not achieve normal sagittal plane hip kinematics. However, previous studies have only conducted group level analysis and as such lack the sensitivity to highlight whether individual patients do achieve normal hip kinematics. As such this study looked to determine whether some patients with well-functioning THA achieve typical sagittal plane hip kinematics.

METHODS

Sagittal plane hip kinematics were collected on 11 well-functioning THA patients (Oxford Hip Score = 46 ± 3) and 10 asymptomatic controls using a 3-dimensional motion analysis system during self-paced walking. High-functioning THA patients were identified as those who displayed sagittal plane hip kinematics that were within the variance of the control group on average, and low-functioning patients as those who did not.

RESULTS

5 THA patients were identified as high-functioning, displaying hip kinematics within the variance of the control group. High-functioning THA patients displayed peak hip flexion and extension values more closely aligned to asymptomatic control group than low-functioning patients. However, hip range of motion was comparable between high- and low-functioning total hip arthroplasty patients and reduced compared to controls.

CONCLUSION

The presence of high-functioning THA patients who display comparable sagittal plane hip kinematics to controls suggests these patients do achieve normative function and challenges the conclusions of previous group level analysis. Understanding why some patients achieve better function post-operatively will aid pre- and post-operative practices to maximise functional recovery.

273 The Consequences of a Failed Screening Programme

Introduction

Controversy exists surrounding the efficacy of the UK screening programme for developmental dysplasia of the hip (DDH).

Method

Clinical records were reviewed in children who were treated surgically for DDH. Demographic data, age and mode of presentation, and surgical treatments were analysed, as well as outcomes, re-operation rate and AVN incidence. Late diagnosis was defined as greater than 4 months.

Results

106 children (16 male, 90 female) underwent surgery from 1997 to 2018. 95 hips were operated for dislocation and 22 were operated for dysplasia. 13 patients had bilateral dislocations. Of the dislocated hips, the median age at diagnosis was 9 months (IQR 2-19). 56% were diagnosed late. In the late diagnosis group the median age for diagnosis was 19 months (IQR 15-21). We have identified an increasing trend in late presentation in recent years. This has been matched with an increasing trend in operation rates for dislocation per 1000 births.

Conclusions

This study demonstrates that DDH is being diagnosed increasingly late, which correlates with an increased need for surgical management. This suggests that the current UK screening programme is failing to identify children with DDH in a timely fashion, which necessitates more aggressive surgical treatment and less favourable outcomes.

274 The Accuracy of Clinical Coding of Developmental Dysplasia of The Hip (DDH) Operations

Aim:

To assess the accuracy of clinical coding of developmental dysplasia of the hip (DDH) operations

Method

106 children underwent surgery for DDH at our turst from 1997 to 2018. Our coding department was sent a list of patients and operation dates and asked to tabulate data on what each operation had been coded as. We compared what each operation was coded as with the procedure actually performed (as per operation notes, clinic letters and intra-operative fluoroscopy images).

Results

Of the 106 patients included in our study, 128 operations were performed. 36 out of 128 (28%) of operations were coded incorrectly. The commonest error was that closed reduction was missed from coding (n = 13). Seven patients did not have their femoral osteotomy coded. Seven patients had a closed reduction incorrectly labelled as an open reduction. Four patients had pelvic osteotomies that were not coded. Two patients had open reductions that were not coded.

Conclusions

We have shown that an unacceptably high number of DDH operations are being coded for incorrectly. This has clear cost implications for the trust. This study questions the use of retrospective coding data in audit and research and suggests inaccuracy when considering the surgical outcomes of developmental dysplasia of the hip.

Combined effect of toe out gait and high tibial osteotomy on knee adduction moment in patients with varus knee deformity

BACKGROUND

Gait adaptations, including toe out gait, have been proposed as treatments for knee osteoarthritis. The clinical application of toe out gait, however, is unclear. This study aims to identify the changes in Knee adduction moment in varus knee deformity assessing toe out gait as an alternative to high tibial osteotomy, and if any change in dynamic loading persists post operatively, when anatomical alignment is restored.

METHODS

Three-dimensional motion analysis was performed on 17 patients with medial compartment knee osteoarthritis and varus deformity prior to undergoing high tibial osteotomy, 13 patients were assessed post-operatively, and results compared to 13 healthy controls.

FINDINGS

Pre-operatively, there was no significant difference between natural and toe out gait for measures of knee adduction moment. Post high tibial osteotomy, first (2.70 to 1.51% BW·h) and second peak (2.28 to 1.21% BW·h) knee adduction moment were significantly reduced, as was knee adduction angular impulse (1.00 to 0.52% BW·h·s), to a healthy level. Adopting toe out gait post-operatively reduced the second peak further to a level below that of healthy controls.

INTERPRETATION

Increasing the foot progression angle from 20° (natural) to 30° in isolation did not significantly alter the knee adduction moment or angular impulse. This suggests that adopting a toe out gait, in isolation, in an already high natural foot progression angle, is not of benefit. Adopting toe out gait post-operatively, however, resulted in a further reduction in the second peak to below that of the healthy control cohort, however, this may increase lateral compartment load.

Determination of plasma homovanillic acid by liquid chromatography with electrochemical detection

We describe a simple method for extracting homovanillic acid (HVA) from plasma. An aliquot of 0.5 ml of the internal standard solution (3-hydroxy-4-methoxycinnamic acid in 0.2 mol/l phosphoric acid) and 0.5 ml of the sample are applied to a 1-ml Bond Elut C18 column prewashed with methanol and 0.2 mol/l phosphoric acid. The sample is drawn through the column at low speed. The column is washed with water and eluted with dichloromethane. The eluate is evaporated under vacuum at ambient temperature and the residue reconstituted with 250 microliters of the mobile phase. A 10-microliters aliquot of the resulting solution is injected onto a 150 mm x 4.6 mm I.D. column packed with 5-microns octadecylsilyl silica particles (Beckman). Peaks are detected coulometrically in the screening-oxidation mode with E1 = +0.25 V and E2 = +0.38 V. In the resulting chromatogram, HVA and the internal standard give sharp peaks and are well separated from solvent and other endogenous electroactive acids. The extraction recovery is 90-95% which allows the determination of 0.5 microgram/l analyte.

Needs of well siblings of persons with schizophrenia

The practical concerns of well siblings of persons with schizophrenia were examined in a descriptive study that included a needs assessment survey and a workshop designed to increase well siblings' knowledge about schizophrenia. A questionnaire focusing on needs for information, support, and practical skills was completed by 88 well siblings and 19 of their spouses. The results indicated a desire for more specific information about schizophrenia, particularly prognosis, and difficulties in communicating and problem solving with siblings with schizophrenia. Although respondents to the questionnaire were neutral about the need for support from other well siblings, participants at the workshop indicated that they found the opportunity to meet and share experiences with other well siblings to be the workshop's strongest feature. The study indicates that well siblings of persons with schizophrenia have specific needs that may differ from those of other family members.