Dual Mobility (DM) Total Hip Replacements (THRs), are becoming widely used but function in-vivo is not fully understood.

The aim of this study was to compare the incidence of impingement of a modular dual mobility with that of a standard cup.

A geometrical model of one subject's bony anatomy \[1\] was developed, a THR was implanted with the cup at a range of inclination and anteversion positions (Corail® stem, Pinnacle® cup (DePuy Synthes)). Two DM variants and one STD acetabular cup were modelled. Joint motions were taken from kinematic data of activities of daily living associated with dislocation \[2\] and walking. The occurrence of impingement was assessed for each component combination, orientation and activity. Implant-implant impingement can occur between the femoral neck and the metal or PE liner (DM or STD constructs respectively) or neck-PE mobile liner (DM only).

The results comprise a colour coded matrix which sums the number of impingement events for each cup position and activity and for each implant variant.

Neck-PE mobile liner impingement, occurred for both DM sizes, for all activities, and most cup placement positions indicating that the PE mobile liner is likely to move at the start of all activities including walking.

For all constructs no placement positions avoided neck-metal (DM) or neck-PE liner (STD) impingementevents in all activities. The least number of events occurred at higher inclination and anteversion component positions. In addition to implant-implant impingement, some instances of bone-bone and implant-bone impingement were also observed.

Consistent with DM philosophy, neck-PE mobile liner impingement and liner motion occurred for all activities including walking. Neck-liner impingement frequency was comparable between both DM sizes (metal liner) and a standard cup (PE liner).

To examine whether Natural Language Processing (NLP) using a state-of-the-art clinically based Large Language Model (LLM) could predict patient selection for Total Hip Arthroplasty (THA), across a range of routinely available clinical text sources.

Data pre-processing and analyses were conducted according to the Ai to Revolutionise the patient Care pathway in Hip and Knee arthroplasty (ARCHERY) project protocol (https://www.researchprotocols.org/2022/5/e37092/). Three types of deidentified Scottish regional clinical free text data were assessed: Referral letters, radiology reports and clinic letters. NLP algorithms were based on the GatorTron model, a Bidirectional Encoder Representations from Transformers (BERT) based LLM trained on 82 billion words of de-identified clinical text. Three specific inference tasks were performed: assessment of the base GatorTron model, assessment after model-fine tuning, and external validation.

There were 3911, 1621 and 1503 patient text documents included from the sources of referral letters, radiology reports and clinic letters respectively. All letter sources displayed significant class imbalance, with only 15.8%, 24.9%, and 5.9% of patients linked to the respective text source documentation having undergone surgery. Untrained model performance was poor, with F1 scores (harmonic mean of precision and recall) of 0.02, 0.38 and 0.09 respectively. This did however improve with model training, with mean scores (range) of 0.39 (0.31–0.47), 0.57 (0.48–0.63) and 0.32 (0.28–0.39) across the 5 folds of cross-validation. Performance deteriorated on external validation across all three groups but remained highest for the radiology report cohort.

Even with further training on a large cohort of routinely collected free-text data a clinical LLM fails to adequately perform clinical inference in NLP tasks regarding identification of those selected to undergo THA. This likely relates to the complexity and heterogeneity of free-text information and the way that patients are determined to be surgical candidates.

Periacetabular osteotomy (PAO) is the preferred treatment for symptomatic acetabular dysplasia in adolescents and young adults. There remains a lack of consensus regarding whether intra-articular work such as labral repair or improvement of femoral offset should be performed at the time of PAO or addressed subsequent to PAO if symptoms warrant. The purpose was to determine the rate of subsequent hip arthroscopy (HA) in a contemporary PAO cohort with no intra-articular work performed at the time of PAO.

From June 2012 to March 2022, 368 rectus sparing PAOs were performed and followed for a minimum of one year (mean 5.9 years). The average age was 24 (range 14–46) and 89% were female. Patients were evaluated at last follow-up for patient-reported outcomes (PROMs). Clinical records were reviewed for complications or subsequent surgery. Radiographs were reviewed for the following acetabular parameters: LCEA, ACEA, AI, and the alpha-angle (AA). Patients were cross-referenced from the two largest hospital systems in our area to determine if subsequent HA was performed. Descriptive statistics were used to analyze risk factors for HA.

16 hips (15 patients) (4.4%) underwent subsequent HA with labral repair and femoral osteochondroplasty most common. For those with a minimum of two years of follow-up, 5.3% underwent subsequent HA. No hips underwent THA; one revision PAO was performed. 14 hips experienced a complication and 99 underwent hardware removal. All PROMs improved significantly post-operatively. Radiographically 80% of hips were in goal for acetabular correction parameters with no significant differences between those who underwent subsequent HA and those who did not.

Rectus sparing PAO is associated with a low rate of subsequent HA for intra-articular pathology at 5-year follow-up. Acetabular correction alone may be sufficient as the primary intervention for the majority of patients with symptomatic acetabular dysplasia.

Intertrochanteric fractures are common, accounting for nearly 30% of all fracture related admissions. Some have suggested that these fractures should be treated in community hospitals so as not to tax the resources of Level One trauma centers. Since many factors predictive of fixation failure are related to technical aspects of the surgery, the purpose of this study was to compare radiographic parameters after fixation comparing trauma fellowship trained surgeons to non-fellowship trained community surgeons to see if these fractures can be treated successfully in either setting.

Using our hospital system's trauma database, we identified 100 consecutive patients treated with cephalomedullary nails by traumatologists, and 100 consecutive patients treated by community surgeons. Quality of reduction, neck shaft angle (NSA), tip-to apex distance (TAD) were compared.

The mean TAD for the trauma group was 10mm compared to 21mm for the community group (p<0.001). The mean postoperative NSA for the trauma group was 133 degrees compared to 127 degrees for the community group (p<0.001). The mean difference in the NSA of the fractured side compared to the normal hip was 2.5 degrees of valgus in the trauma group compared to 5 degrees of varus for the community group (p<0.001). There were 93 good reductions in the trauma group compared to 19 in the community group (p<0.001). There were no poor reductions in the trauma group and 49 poor reductions in the community group (p<0.001).

Fellowship trained traumatologists achieved significantly more accurate reductions and implant placement during cephalomedullary nailing of intertrochanteric hip fractures.

Dual Mobility (DM) Total Hip Replacements (THRs) were introduced to reduce dislocation risk, which is the most common cause of early revision. The in-vivo mechanics of these implants is not well understood, despite their increased use in both elective and trauma settings. Therefore, the aim of this study was to comprehensively assess retrieved DM polyethylene liners for signs of damage using visual inspection and semi-quantitative geometric assessment techniques.

Retrieved DM liners (n=20) were visually inspected for the presence of seven established modes of polyethylene damage. If embedded debris was identified on the external surface, its material composition was characterised using energy-dispersive x-ray analysis (EDX). Additionally, each liner was geometrically assessed for signs of wear/deformation using a validated methodology.

Visual inspection of the liners revealed that scratching and pitting were the most common damage modes on either surface. Burnishing was observed on 50% and 15% of the internal and external surfaces, respectively. In addition, embedded debris was identified on 25% of the internal and 65% of the external surfaces. EDX analysis of the debris identified several materials including iron, titanium, cobalt-chrome, and tantalum. Geometric analysis demonstrated highly variable damage patterns across the liners.

The results of this study provide insight into the in-vivo mechanics of DM bearings. For example, the results suggest that the internal bearing (i.e., between the head and liner) acts as the primary articulation site for DM-THRs as evidenced by a higher incidence of burnishing and larger, more concentrated regions of penetration across the liners’ internal surfaces. Furthermore, circumferential, and crescent-shaped damage patterns were identified on the articulating surfaces of the liners thus providing evidence that these components can rotate within the acetabular shell with varying degrees of mobility. The mechanics of DM bearings are complex and may be influenced by several factors (e.g., soft tissue fibrosis, patient activities) and thus further investigation is warranted.

Finally, the results of this study suggest that DM liners may be susceptible to ex-vivo surface damage and thus caution is advised when handling and/or assessing these types of components.

Background

The purpose of this study is to evaluate the early outcomes with the use of a smartphone-based exercise and educational platform after primary total hip arthroplasty compared to a standard of care control group.

Introduction

Periacetabular osteotomy (PAO) is the preferred treatment for symptomatic acetabular dysplasia in adolescents and young adults. There remains a lack of consensus regarding whether intra-articular work such as labral repair or improvement of femoral offset should be performed at the time of PAO or addressed subsequent to PAO if symptoms warrant. The purpose of this review was to determine the rate of subsequent hip arthroscopy (HA) in a contemporary PAO cohort with no intra-articular work performed at the time of PAO.

Introduction

Radiographic assessment of acetabular fragment positioning during periacetabular osteotomy (PAO) is of paramount importance. Plain radiographic examination is time and resource intensive. Fluoroscopic based assessment is increasingly utilized but can introduce distortion. Our purpose was to determine the correlation of intraoperative fluoroscopy-based measurements with a fluoroscopic tool that corrects for distortion with postoperative plain-film measurements.

Introduction

The aim of this study was to compare patient reported outcomes, radiographic measurements, and survival free from total hip arthroplasty (THA) in patients who underwent periacetabular osteotomy (PAO) for mild, moderate, or severe developmental dysplasia of the hip (DDH).

Total hip arthroplasty (THA) in the young patient has been associated with higher rates of revision and perioperative complications. For clinicians and patients alike, there remains a desire to better characterize the durability of THA in young patients. We reviewed secondary data from our institutional database for all patients who underwent primary THA from January 2000 to May 2015. Patients were identified using ICD-9 procedure code 81.51. Our primary interest was the survival of implants in patients 30 years of age or younger (n=167) while using a contemporaneous cohort of patients age 60 and older as a control (n=1359). Failure was defined as revision THA for any reason. Cox regression with robust standard errors was used to calculate hazard ratios. A population-averaged Poisson regression analysis was used to compare complication rates.

The rate of all-cause revision THA was 2.4 times greater (95% CI 1.10 – 5.37, p=0.028) in young patients (7%, 12/167) undergoing primary or conversion to THA compared to their elderly counterparts (3.7%, 50/1,359). Survival at 10 years was 89% (95% CI 82 – 94) in the young cohort and 96% (94 – 97) in the elderly cohort. The primary reasons for revision in young that patients compared to their elderly counterparts included metal-on-metal implants (IRR 8.12, 95% CI 2.04 – 32.38, p=0.003).

These data demonstrate that patients 30 years of age and younger substantially benefit from THA but should be warned of higher risk of subsequent revision.