A complete cement mantle is important for the longevity of a total hip replacement. In the minimally-invasive direct anterior approach used at the Innsbruck University hospital, the femoral component has to be inserted into the femoral canal by an angulated movement. In a cadaver study, the quality and the extent of the cement mantle surrounding 13 Exeter femoral components implanted straight through a standard anterolateral transgluteal approach were compared with those of 13 similar femoral components implanted in an angulated fashion through a direct anterior approach. A third-generation cementing technique was used. The inner and outer contours of the cement mantles was traced from CT scans and the thickness and cross-sectional area determined. In no case was the cement mantle incomplete. The total mean thickness of the cement mantle was 3.62 mm (95% confidence interval 3.59 to 3.65). The mean thickness in the group using the minimally-invasive approach was 0.16 mm less than that in the anterolateral group. The distribution of the thickness was similar in the two groups. The mean thickness was less on the anteromedial and anterolateral aspect than on the posterior aspect of the femur. There is no evidence that the angulated introduction of Exeter femoral components in the direct anterior approach in cadavers compromises the quality, extent or thickness of the cement mantle

Evidence supporting the use of virtual reality (VR) training in orthopaedic procedures is rapidly growing. However, the impact of the timing of delivery of this training is yet to be tested. We aimed to investigate whether spaced VR training is more effective than massed VR training. 24 medical students with no hip arthroplasty experience were randomised to learning the direct anterior approach total hip arthroplasty using the same VR simulation, training either once-weekly or once-daily for four sessions. Participants underwent a baseline physical world assessment on a saw bone pelvis. The VR program recorded procedural errors, time, assistive prompts required and hand path length across four sessions. The VR and physical world assessments were repeated at one-week, one-month, and 3 months after the last training session. Baseline characteristics between the groups were comparable (p > 0.05). The daily group demonstrated faster skills acquisition, reducing the median ± IQR number of procedural errors from 68 ± 67.05 (session one) to 7 ± 9.75 (session four), compared to the weekly group's improvement from 63 ± 27 (session one) to 13 ± 15.75 (session four), p < 0.001. The weekly group error count plateaued remaining at 14 ± 6.75 at one-week, 16.50 ± 16.25 at one-month and 26.45 ± 22 at 3-months, p < 0.05. However, the daily group showed poorer retention with error counts rising to 16 ± 12.25 at one-week, 17.50 ± 23 at one-month and 41.45 ± 26 at 3-months, p<0.01. A similar effect was noted for the number of assistive prompts required, procedural time and hand path length. In the real-world assessment, both groups significantly improved their acetabular component positioning accuracy, and these improvements were equally maintained (p<0.01). Daily VR training facilitates faster skills acquisition; however weekly practice has superior skills retention

Introduction and Objective. Interest for direct anterior approach (DAA) in hip hemiarthroplasty (HHA) has greatly increased in recent years, however which is the best surgical approach in hip replacement treating femoral neck fractures (FNFs) is already unclear. The aim of this study is to perform a radiographic and perioperative complications analysis by comparing the direct anterior approach (DAA) with the direct lateral approach (DLA) in patients treated with hemiarthroplasty for FNFs. Materials and Methods. Patients with FNFs surgically treated between 2016–2020 with HHA were enrolled. The radiographical outcomes of DAA and DLA are compared. Several peri-operative and post-operative variables were evaluated: mean surgery time, complications as periprosthetic fractures or episodes of dislocation, the average of post-operative diaphyseal filling of the stem (Canal Fill Index, CFI), the extent of heterotopic ossification (HO) (simplified Broker classification) and metadiaphiseal bone loss (Paprosky classification) within one year from surgery. Results. 86 patients underwent HHA by DAA and 80 patients by DLA. The two groups are qualitatively comparable. No statistically significate differences were showed in all variables analyzed (p>0.05). The average of surgical time of DAA were 61 minutes compared to 67 of DLA. No differences were showed in the post-operative CFI (DAA 0.71 ± 6.1; DLA 0.76 ± 13.5), the extent of the HO (DAA 79.07% low; DLA 75% low) and metadiaphiseal bone loss (DAA Grade I 91.86%; DLA Grade I 93.75%). Regarding perioperative complications, we have discovered only one periprosthetic fracture each group. Although there was no statistically significant difference, we highlighted a higher number of dislocations in the group of DLA (2 episodes vs no one). Conclusions. In this study we have shown that the DAA is an adequate surgical choice comparing with the classical DLA for FNFs treated with HHA. The analysis of our radiographic parameters and perioperative complications have not shown a significant difference between the two surgical approach. This study is limited by a purely radiographic analysis without addition of clinical parameters

Range of Motion (ROM) assessments are routinely used during joint replacement to evaluate joint stability before, during and after surgery to ensure the effective restoration of patient biomechanics. This study aimed to quantify axial torque in the femur during ROM assessment in total hip arthroplasty to define performance criteria against which hip instruments can be verified. Longer term, this information may provide the ability to quantitatively assess joint stability, extending to quantitation of bone preparation and quality. Joint loads measured with strain-gaged instruments in five cadaveric femurs prepared using posterior approach were analysed. Variables such as surgeon-evaluator, trial offset and specimen leg and weight were used to define 13 individual setups and paired with surgeon appraisal of joint tension for each setup. Peak torque loads were then identified for specific motions within the ROM assessment. The largest torque measured in most setups was observed during maximum extension and external rotation of the joint, with a peak torque of 13Nm recorded in a specimen weighing 98kg. The largest torque range (19.4Nm) was also recorded in this specimen. Other motions within the trial reduction showed clear peaks in applied torque but with lower magnitude. Relationships between peak torque, torque range and specimen weight produced an R2 value greater than 0.65. The data indicated that key influencers of torsional loads during ROM were patient weight, joint tension and limb motion. This correlation with patient weight should be further investigated and highlights the need for population representation during cadaveric evaluation. Although this study considered a small sample size, consistent patterns were seen across several users and specimens. Follow-up studies should aim to increase the number of surgeon-evaluators and further vary specimen size and weight. Consideration should also be given to alternative surgical approaches such as the Direct Anterior Approach

There is controversy regarding the effect of different approaches on recovery after THR. Collecting detailed relevant data with satisfactory compliance is difficult. Our retrospective observational multi-center study aimed to find out if the data collected via a remote coaching app can be used to monitor the speed of recovery after THR using the anterolateral (ALA), posterior (PA) and the direct anterior approach (DAA). 771 patients undergoing THR from 13 centers using the moveUP platform were identified. 239 had ALA, 345 DAA and 42 PA. There was no significant difference between the groups in the sex of patients or in preoperative HOOS Scores. There was however a significantly lower age in the DAA (64,1y) compared to ALA (66,9y), and a significantly lower Oxford Hip Score in the DAA (23,9) compared to PA(27,7). Step count measured by an activity tracker, pain killer and NSAID use was monitored via the app. We recorded when patients started driving following surgery, stopped using crutches, and their HOOS and Oxford hip scores at 6 weeks. Overall compliance with data request was 80%. Patients achieved their preoperative activity level after 25.8, 17,7 and 23.3 days, started driving a car after 33.6, 30.3 and 31.7 days, stopped painkillers after 27.5, 20.2 and 22.5 days, NSAID after 30.3, 25.7, and 24.7 days for ALA, DAA and PA respectively. Painkillers were stopped and preoperative activity levels were achieved significantly earlier favoring DAA over ALA. Similarly, crutches were abandoned significantly earlier (39.9, 29.7 and 24.4 days for ALA, DAA and PA respectively) favoring DAA and PA over ALA. HOOS scores and Oxford Hip scores improved significantly in all 3 groups at 6 weeks, without any statistically significant difference between groups in either Oxford Hip or HOOS subscores. No final conclusion can be drawn as to the superiority of either approach in this study but the remote coaching platform allowed the collection of detailed data which can be used to advise patients individually, manage expectations, improve outcomes and identify areas for further research

Dual mobility (DM) bearing implants reduce the incidence of dislocation following total hip arthroplasty (THA) and as such they are used for the treatment of hip instability in both primary and revision cases. The aim of this study was to compare lower limb muscle activity of patients who underwent a total hip arthroplasty (THA) with a dual mobility (DM) or a common cup (CC) bearing compared to healthy controls (CON) during a sit to stand task. A total of 21 patients (12 DM, 9 CC) and 12 CON were recruited from the local Hospital. The patients who volunteered for the study were randomly assigned to either a DM or a CC cementless THA after receiving informed consent. All surgeries were performed by the same surgeon using the direct anterior approach. Participants underwent electromyography (EMG) and motion analysis while completing a sit-to-stand task. Portable wireless surface EMG probes were placed on the vastus lateralis, rectus femoris, biceps femoris, semitendinosus (ST), gluteus medius and tensor fasciae latae muscles of the affected limb in the surgical groups and the dominant limb in the CON group. Motion capture was used to record lower limb kinematics and kinetics. Muscle strength was recorded using a hand-held dynamometer during maximal voluntary isometric contraction (MVIC) testing. Peak linear envelope (peakLE) and total muscle activity (iEMG) were extrapolated and normalized to the MVIC and time cycle for the sit to stand task. Using iEMG, quadriceps-hamstrings muscle co-activation index was calculated for the task. Nonparametric Kruskal Wallace ANOVA tests and Wilcoxon rank sum tests were used to identify where significant (p < 0.05) differences occurred. The DM group had greater iEMG of the ST muscle compared to the CC (p=0.045) and the CON (p=0.015) groups. The CC group had lower iEMG for hamstring muscles compared to the DM (p=0.041) group. The DM group showed lower quadriceps-hamstrings co-activation index compared to the CON group and it approached significance (p=0.054). The CC group had greater anterior pelvis tilt compared to both DM (p=0.043) and the CON (p=0.047) groups. The DM also had larger knee varus angles and less knee internal rotation compared to both groups, however this never reached significance. No significant differences in muscle strength existed between the groups. Higher ST muscle activity in the DM group is explained by the reduction in internal rotation at the knee joint as the ST muscle was more active to resist the varus forces during the sit-to-stand task. Reduced quadriceps activity in the CC group is explained by increased pelvic anterior tilt as this would shorten the moment arm and muscle length in the quadriceps, ultimately reducing quadriceps muscle activity. The reduced co-activation between quadriceps and hamstrings activity in the DM group compared to the CC and CON groups is related to better hip function and stability. Combining lower co-activation and larger range of motion for the DM group without impingement, this implant seems to offer better prevention against THA subluxation and less wear of the implant