Equivalent revision rates and patient reported outcomes with routine use of a short (125mm) cemented stem for total hip arthroplasty compared to a standard length (150mm) cemented stem. A two surgeon series of 1335 patients.

BACKGROUND: Routine total hip arthroplasty (THA) using a short cemented stem as compared with a standard length cemented stem may have benefits in terms of stress distribution, bone preservation, stem subsidence and ease of revision surgery. Two senior arthroplasty surgeons transitioned their routine femoral implant from a standard 150 mm Exeter V40 cemented stem to a short 125 mm Exeter V40 cemented stem for all patients over the course of several years. We analysed revision rates, adjusted survival, and PROMS scores for patients who received a standard stem and a short stem in routine THA. METHODS: All THAs performed by the two surgeons between January 2011 and December 2021 were included. All procedures were performed using either a 150 mm or 125 mm Exeter V40 stem. Demographic data, acetabular implant type, and outcome data including implant survival, reason for revision, and post-operative Oxford Hip Scores were obtained from the New Zealand Joint Registry (NZJR), and detailed survival analyses were performed. Primary outcome was revision for any reason. Reason for revision, including femoral or acetabular failure, and time to revision were also recorded. RESULTS: 1335 THAs were included. 516 using the 150 mm stem and 819 using the 125 mm stem. There were 4055.5 and 3227.8 component years analysed in the standard stem and short stem groups respectively due to a longer mean follow up in the 150 mm group. Patient reported outcomes were comparable across all groups. Revision rates were comparable between the standard 150 mm stem (0.44 revisions/100 component years) and the short 125 mm stem (0.56 revisions/100 component years) with no statistically significant difference found (p = 0.240). CONCLUSION: Routine use of a short 125 mm stem had no statistically significant impact on revision rate or PROMS scores when compared to a standard 150 mm stem. There may be benefits to routine use of a short cemented femoral implant.

Classification system for partial distal biceps tendon tears: a descriptive 3-Tesla magnetic resonance imaging study of tear morphology.

BACKGROUND: There is minimal literature on the morphology of partial distal biceps tendon (DBT) tears. We sought to investigate tear morphology by retrospectively reviewing 3-Tesla magnetic resonance imaging (3T MRI) scans of elbows with partial DBT tears and to propose a basic classification system. METHODS: 3T MRI scans of elbows with partial DBT tears were retrospectively reviewed by two experienced observers. Basic demographic data were collected. Tear morphology was recorded including type, presence of retraction (>5 mm), and presence of discrete long-head and short-head tendons at the DBT insertion. RESULTS: For analysis, 44 3T MRI scans of 44 elbows with partial DBT tears were included. There were 9 isolated long-head tears (20%), 13 isolated short-head tears (30%), 2 complete long-head tears with a partial short-head tear (5%), 5 complete short-head tears with a partial long-head tear (11%), and 15 peel-off tears (34%). Retraction was seen in 5 or 44 partial tears (11%), and 13 of the 44 DBTs were bifid tendons at the insertion (30%). CONCLUSIONS: Partial DBT tears can be classified into five sub-types: long-head isolated tears, short-head isolated tears, complete long-head tears with partial short-head involvement, complete short-head tears with partial long-head involvement, and peel-off tears. Classification of tears may have implications for operative and non-operative management. Level of evidence: III.

Localization within Hostile Indoor Environments for Emergency Responders.

Recent advances in techniques to improve indoor localization accuracy for personnel and asset tracking challenges has enabled wide-spread adoption within the retail, manufacturing, and health care industries. Most currently deployed systems use distance estimates from known reference locations to localize a person or asset using geometric lateration techniques. The distances are determined using one of many radio frequency (RF) based ranging techniques. Unfortunately, such techniques are susceptible to interference and multipath propagation caused by obstructions within buildings. Because range inaccuracies from known locations can directly lead to incorrect position estimates, these systems often require careful upfront deployment design to account for site-specific interference sources. However, the upfront system deployment requirements necessary to achieve high positioning accuracy with RF-based ranging systems makes the use of such systems impractical, particularly for structures constructed of challenging materials or dense configurations. In this paper, we evaluate and compare the accuracy and precision of alternative RF-based devices within a range of indoor spaces composed of different materials and sizes. These spaces range from large open areas such as gymnasiums to confined engineering labs of traditional buildings as well as training buildings at the local Fire Department Training Facility. Our goal is to identify the impact of alternative RF-based systems on localization accuracy and precision specifically for first responders that are called upon to traverse structures composed of different materials and configurations. Consequently, in this study we have specifically chosen spaces that are likely to be encountered by firefighters during building fires or emergency medical responses. Moreover, many of these indoor spaces can be considered hostile using RF-based ranging techniques. We built prototype wearable localization edge devices designed for first responders and characterize both ranging and localization accuracy and precision using alternative transceivers including Bluetooth Low Energy, 433 MHz, 915 MHz, and ultra-wide band. Our results show that in hostile environments, using ultra-wide band transceivers for localization consistently outperforms the alternatives in terms of precision and accuracy.

Defining the proximity of the axillary nerve from defined anatomic landmarks: an in vivo magnetic resonance imaging study.

BACKGROUND: The location of the axillary nerve in the shoulder makes it vulnerable to traumatic or iatrogenic injury. Cadaveric studies have reported the location of the axillary nerve but are limited because of tissue compression, dehydration, and decay. Three-Tesla (T) magnetic resonance imaging (MRI) allows high anatomic resolution of neural structures. The aim of our study was to better define the location of the axillary nerve from defined bony surgical landmarks in vivo, using MRI scan. METHODS: Using MRI, we defined a number of anatomic points and measured the distance from these to the perineural fat surrounding the axillary nerve using simultaneous tracker lines on both images. Two observers were used. RESULTS: A total of 187 consecutive 3-T MRI shoulder scans were included. Mean age was 57.9 years (range 18-86). The axillary nerve was located at a mean of 14.1 mm inferior from the bony glenoid at the anterior border, 11.9 mm from the midpoint, and 12.0 mm from the posterior border. There was a significant difference between distance at the anterior border and midpoint (P < .001), and between the anterior and posterior borders (P < .001). The axillary nerve was located at a mean of 12.6 mm medial to the humeral shaft at the anterior border, 9.9 mm at the midpoint, and 8.6 mm from the posterior border. There was a significant difference between distance at the anterior border and midpoint (P = .008) and between the anterior and posterior borders (P = .002). The mean distance of the axillary nerve from the anterolateral edge of the acromion was 53.3 mm (95% confidence interval [CI] 52.3, 54.2; range 33.9-76.3). The mean distance of the axillary nerve from the inferior edge of the capsule was 2.7 mm (95% CI 2.9, 3.1; range 0.3-9.9). There was a positive correlation between humeral head diameter and axillary nerve distance from the inferior glenoid (R2 = 0.061, P < .001). There was a positive correlation between humeral head diameter and distance from the anterolateral edge of the acromion (R2 = 0.140, P < .001). CONCLUSION: Our study has defined the proximity of the axillary nerve from defined anatomic landmarks. The proximity of the axillary nerve to the inferior glenoid and medial humeral shaft changes as the axillary nerve passes from anterior to posterior. The distance of the axillary nerve from the anterolateral edge of the acromion remains relatively constant. Both sets of distances may be affected by humeral head size. The study has relevance to the shoulder surgeon when considering "safe zones" during arthroscopic or open surgery.

Dedicated training program for shoulder sonography: the results of a quality program reverberate with everyone.

OBJECTIVES: The purpose of this study was to define and report on the effect of a comprehensive musculoskeletal sonography training program to improve accuracy (sensitivity and specificity) for the diagnosis of rotator cuff tears in relatively inexperienced operators. METHODS: Before the training program was implemented, radiologists (n = 12) had a mean of 2 years (range, <1-12 years) of experience performing and interpreting musculoskeletal sonography. Pre- and post-training shoulder sonographic results were compared to surgical reports or, in their absence, to shoulder magnetic resonance imaging or computed tomographic arthrographic results if within 2 months of the sonographic examination. A total of 82 patients were included in the pre-training group (January 2010-December 2011), and 50 patients were included in the post-training group (January 2012-June 2013). The accuracy, sensitivity, specificity, and positive and negative predictive values were determined for the presence or absence of supraspinatus and infraspinatus tendon tears. RESULTS: After implementation of the training program, the sensitivity of sonography for detecting full-thickness rotator cuff tears increased by 14%, and the sensitivity for detecting partial-thickness rotator cuff tears increased by 3%. CONCLUSIONS: Quality improvement programs and acquisition standardization along with ongoing, focused case conferences for the entire care team increased the sensitivity of shoulder sonography for diagnosing both full- and partial-thickness rotator cuff tears, independent of the years of operator experience.