Aims. The reduction in mobility due to hip diseases in children is likely to affect their physical activity (PA) levels. Physical inactivity negatively influences quality of life and health. Our aim was to objectively measure PA in children with hip disease, and correlate it with the Patient-Reported Outcomes Measurement Information System (PROMIS) Mobility Score. Methods. A total of 28 children (12 boys and 16 girls) with hip disease aged between 8and 17 years (mean 12 (SD 3)) were studied between December 2018 and July 2019. Children completed the PROMIS Paediatric Item Bank v. 2.0 – Mobility Short Form 8a and wore a hip accelerometer (ActiGraph) for seven consecutive days. Sedentary time (ST), light PA (LPA), moderate to vigorous PA (MVPA), and vigorous PA were calculated from the accelerometers' data. The PROMIS Mobility score was classified as normal, mild, and moderate functions, based on the PROMIS cut scores on the physical function metric. A one-way analysis of covariance (ANCOVA) was used to assess differences among mobility (normal; mild; moderate) and measured PA and relationships between these variables were assessed using bivariate Pearson correlations. Results. Children classified as normally functioning on the PROMIS had less ST (p = 0.002), higher MVPA, (p = 0.002) and VPA (p = 0.004) compared to those classified as mild or moderate function. A moderate correlation was evident between the overall PROMIS score and daily LPA (r = 0.462, n = 28; p = 0.013), moderate-to-vigorous PA (r = 0.689, n = 28; p = 0.013) and vigorous PA (VPA) (r = 0.535, n = 28; p = 0.013). No correlation was evident between the mean daily ST and overall PROMIS score (r = -0.282, n = 28; p = 0.146). Conclusion. PROMIS Pediatric Mobility tool correlates well with experimentally measured levels of physical activity in children with hip disease. We provide external validity for the use of this tool as a measure of physical activity in children. Cite this article: Bone Joint J 2021;103-B(2):405–410

Aims. The purpose of this exploratory study was to investigate if the 24-hour activity profile (i.e. waking activities and sleep) objectively measured using wrist-worn accelerometry of patients scheduled for total hip arthroplasty (THA) improves postoperatively. Patients and Methods. A total of 51 THA patients with a mean age of 64 years (24 to 87) were recruited from a single public hospital. All patients underwent THA using the same surgical approach with the same prosthesis type. The 24-hour activity profiles were captured using wrist-worn accelerometers preoperatively and at 2, 6, 12, and 26 weeks postoperatively. Patient-reported outcomes (Hip Disability and Osteoarthritis Outcome Score (HOOS)) were collected at all timepoints except two weeks postoperatively. Accelerometry data were used to quantify the intensity (sedentary, light, moderate, and vigorous activities) and frequency (bouts) of activity during the day and sleep efficiency. The analysis investigated changes with time and differences between Charnley class. Results. Patients slept or were sedentary for a mean of 19.5 hours/day preoperatively and the 24-hour activity pattern did not improve significantly postoperatively. Outside of sleep, the patients spent their time in sedentary activities for a mean of 620 minutes/day (. sd. 143) preoperatively and 641 minutes/day (. sd. 133) six months postoperatively. No significant improvements were observed for light, moderate, and vigorous intensity activities (p = 0.140, p = 0.531, and p = 0.407, respectively). Sleep efficiency was poor (< 85%) at all timepoints. There was no postoperative improvement in sleep efficiency when adjusted for medications (p > 0.05). Patient-reported outcome measures showed a significant improvement with time in all domains when compared with preoperative levels. There were no differences with Charnley class at six months postoperatively. However, Charnley class C patients were more sedentary at two weeks postoperatively when compared with Charnley class A patients (p < 0.05). There were no further differences between Charnley classifications. Conclusion. This study describes the 24-hour activity profile of THA patients for the first time. Prior to THA, patients in this cohort were inactive and slept poorly. This cohort shows no improvement in 24-hour activity profiles at six months postoperative. Cite this article: Bone Joint J 2019;101-B:415–425

Aims. Total hip arthroplasty (THA) has well known subjective benefits, but little is known objectively about the recovery of mobility in the early post-operative period. Patients and Methods. A total of 33 patients aged > 60 years who underwent elective primary THA had their activity monitored for 30 days post-operatively using an at-home (Fitbit) ankle accelerometer. Their mean age was 70.7 years (61 to 86); 15 (45.5%) were female. The rate of compliance and the mean level of activity were determined. Comparisons between subgroups based on age, body mass index (BMI), surgical approach, and the destination of the patients when discharged were also performed. Results. The mean compliance over the 30 days was 26.7 days (16 to 30; 89%) of use. The mean number of steps increased from 235 (5 to 1152) to 2563 (87 to 7280) (p < 0.001) between the first and the 30th post-operative day. Age < 70 years and an anterior surgical approach were significantly associated with higher levels of activity (1600 to 2400 (p = 0.016 to 0.031) and 1000 to 1800 (p = 0.017 to 0.037) more steps per day, respectively) between the second and the fourth week post-operatively. There was also a trend towards higher levels of activity in those who were discharged to their home rather than to a nursing facility (a mean of 1500 more steps per day, p = 0.02). BMI greater or less than 30 kg/m. 2. was not predictive of activity (p = 0.45 to 0.98). Conclusion. At-home remote mobility monitoring using existing commercially available technology is feasible in patients who have undergone THA. It showed a clear trend towards increased activity with the passage of time. Additionally, the remote device was able to detect differences in levels of activity clearly between patients in relation to variables of interest including age, BMI, surgical approach, and the destination of the patient at the time of discharge from hospital. Such monitoring may allow for the early identification and targeted intervention in patients who recover slowly. Cite this article: Bone Joint J 2016;98-B:1450–4

There is evidence that high levels of physical activity following arthroplasty of the hip or knee can lead to early revision. However, the term ‘highly active’ is not well defined. . A validated ankle accelerometer was used to quantify activity in 13 patients, who had undergone a total of 20 arthroplasties of the lower limbs and who had active lifestyles. The assessments were taken at a mean of 8.7 years post-operatively (1.8 to 15.8). The mean gait cycles per day was 8273 (5964 to 12 557), which extrapolates to 3.0 million cycles per year (cpy) (2.2 to 4.6). The mean percentage of time spent in high activity mode was 4.3%, or about one hour per day. The mean percentage of cycles in high activity was 40%. . Based on these data, we propose the following definitions of high activity: > 3 million cpy; one hour per day in high activity mode; 40% of cycles in high activity mode. . Extrapolating the sample of activity over the time since operation, the mean cycles per arthroplasty was 25.2 million, with a maximum of 44.1 million. No joint has been revised, or shows evidence of impending failure. Cite this article: Bone Joint J 2016;98-B(1 Suppl A):95–7

We developed a method of applying vibration to the impaction bone grafting process and assessed its effect on the mechanical properties of the impacted graft. Washed morsellised bovine femoral heads were impacted into shear test rings. A range of frequencies of vibration was tested, as measured using an accelerometer housed in a vibration chamber. Each shear test was repeated at four different normal loads to generate stress-strain curves. The Mohr-Coulomb failure envelope from which shear strength and interlocking values are derived was plotted for each test. The experiments were repeated with the addition of blood in order to replicate a saturated environment. Graft impacted with the addition of vibration at all frequencies showed improved shear strength when compared with impaction without vibration, with 60 Hz giving the largest effect. Under saturated conditions the addition of vibration was detrimental to the shear strength of the aggregate. The civil-engineering principles of particulate settlement and interlocking also apply to impaction bone grafting. Although previous studies have shown that vibration may be beneficial in impaction bone grafting on the femoral side, our study suggests that the same is not true in acetabular revision

We aim to explore the potential technologies for monitoring and assessment of patients undergoing arthroplasty by examining selected literature focusing on the technology currently available and reflecting on possible future development and application. The reviewed literature indicates a large variety of different hardware and software, widely available and used in a limited manner, to assess patients’ performance. There are extensive opportunities to enhance and integrate the systems which are already in existence to develop patient-specific pathways for rehabilitation.

Cite this article: Bone Joint J 2022;104-B(10):1104–1109.

Aims

Conventional patient-reported surveys, used for patients undergoing total hip arthroplasty (THA), are limited by subjectivity and recall bias. Objective functional evaluation, such as gait analysis, to delineate a patient’s functional capacity and customize surgical interventions, may address these shortcomings. This systematic review endeavours to investigate the application of objective functional assessments in appraising individuals undergoing THA.

Aims

The purpose of this study is to evaluate early outcomes with the use of a smartphone-based exercise and educational care management system after total hip arthroplasty (THA) and demonstrate decreased use of in-person physiotherapy (PT).

Aims

The purpose is to determine the non-inferiority of a smartphone-based exercise educational care management system after primary knee arthroplasty compared with a traditional in-person physiotherapy rehabilitation model.

We compared the dynamic instability of 25 dysplastic hips in 25 patients using triaxial accelerometry before and one year after periacetabular osteotomy. We also evaluated the hips clinically using the Harris hip score and assessed acetabular orientation by radiography before surgery and after one year. The mean overall magnitude of acceleration was significantly reduced from 2.30 m/s² (sd 0.57) before operation to 1.55 m/s² (sd 0.31) afterwards. The mean Harris hip score improved from 78.08 (47 to 96) to 95.36 points (88 to 100). The radiographic parameters all showed significant improvements.

This study suggests that periacetabular osteotomy provides pain relief, improves acetabular cover and reduces the dynamic instability in patients with dysplastic hips.

Total knee replacement (TKR) smart tibial trials have load-bearing sensors which will show quantitative compartment pressure values and femoral-tibial tracking patterns. Without smart trials, surgeons rely on feel and visual estimation of imbalance to determine if the knee is optimally balanced. Corrective soft-tissue releases are performed with minimal feedback as to what and how much should be released. The smart tibial trials demonstrate graphically where and how much imbalance is present, so that incremental releases can be performed. The smart tibial trials now also incorporate accelerometers which demonstrate the axial alignment. This now allows the surgeon the option to perform a slight recut of the tibia or femur to provide soft-tissue balance without performing soft-tissue releases. Using a smart tibial trial to assist with soft-tissue releases or bone re-cuts, improved patient outcomes have been demonstrated at one year in a multicentre study of 135 patients (135 knees).

Cite this article: Bone Joint J 2014;96-B(11 Suppl A):78–83.

In this study we quantified and characterised the return of functional mobility following open tibial fracture using the Hamlyn Mobility Score. A total of 20 patients who had undergone reconstruction following this fracture were reviewed at three-month intervals for one year. An ear-worn movement sensor was used to assess their mobility and gait. The Hamlyn Mobility Score and its constituent kinematic features were calculated longitudinally, allowing analysis of mobility during recovery and between patients with varying grades of fracture. The mean score improved throughout the study period. Patients with more severe fractures recovered at a slower rate; those with a grade I Gustilo-Anderson fracture completing most of their recovery within three months, those with a grade II fracture within six months and those with a grade III fracture within nine months.

Analysis of gait showed that the quality of walking continued to improve up to 12 months post-operatively, whereas the capacity to walk, as measured by the six-minute walking test, plateaued after six months.

Late complications occurred in two patients, in whom the trajectory of recovery deviated by > 0.5 standard deviations below that of the remaining patients. This is the first objective, longitudinal assessment of functional recovery in patients with an open tibial fracture, providing some clarification of the differences in prognosis and recovery associated with different grades of fracture.

Cite this article: Bone Joint J 2015; 97-B:1118–25.

Surgical reconstruction of articular surfaces by transplantation of osteochondral autografts has shown considerable promise in the treatment of focal articular lesions. During mosaicplasty, each cylindrical osteochondral graft is centred over the recipient hole and delivered by impacting the articular surface. Impact loading of articular cartilage has been associated with structural damage, loss of the viability of chondrocytes and subsequent degeneration of the articular cartilage. We have examined the relationship between single-impact loading and chondrocyte death for the specific confined-compression boundary conditions of mosaicplasty and the effect of repetitive impact loading which occurs during implantation of the graft on the resulting viability of the chondrocytes.

Fresh bovine and porcine femoral condyles were used in this experiment. The percentage of chondrocyte death was found to vary logarithmically with single-impact energy and was predicted more strongly by the mean force of the impact rather than by the number of impacts required during placement of the graft. The significance of these results in regard to the surgical technique and design features of instruments for osteochondral transplantation is discussed.