Computer-aided surgical systems commonly use preoperative CT scans when performing pelvic osteotomies for intraoperative navigation. These systems have the potential to improve the safety and accuracy of pelvic osteotomies, however, exposing the patient to radiation is a significant drawback. In order to reduce radiation exposure, we propose a new smooth extrapolation method leveraging a partial pelvis CT and a statistical shape model (SSM) of the full pelvis in order to estimate a patient's complete pelvis. A SSM of normal, complete, female pelvis anatomy was created and evaluated from 42 subjects. A leave-one-out test was performed to characterise the inherent generalisation capability of the SSM. An additional leave-one-out test was conducted to measure performance of the smooth extrapolation method and an existing “cut-and-paste” extrapolation method. Unknown anatomy was simulated by keeping the axial slices of the patient's acetabulum intact and varying the amount of the superior iliac crest retained; from 0% to 15% of the total pelvis extent. The smooth technique showed an average improvement over the cut-and-paste method of 1.31 mm and 3.61 mm, in RMS and maximum surface error, respectively. With 5% of the iliac crest retained, the smoothly estimated surface had an RMS surface error of 2.21 mm, an improvement of 1.25 mm when retaining none of the iliac crest. This anatomical estimation method creates the possibility of a patient and surgeon benefiting from the use of a CAS system and simultaneously reducing the patient's radiation exposure.

Summary Statement

The peripheral neuronal phenotype is significantly altered in rotator cuff tendinopathy (RCT) with a clear upregulation of the Glutaminergic system being present in disease.

Introduction

The goal of this work is to develop a system for three-dimensional tracking of the acetabular fragment during periacetabular osteotomy (PAO) using x-ray images. For PAO, the proposed x-ray image-based navigation provides geometrical and biomechanical assessment of the acetabular fragment, which is unavailable in the conventional procedure, without disrupting surgical workflow or requiring tracking devices.

Standard evaluation and diagnosis of pincer-type femoroacetabular impingment (FAI) relies on anteroposterior (AP) radiographs, clinical evaluation, and/or magnetic resonance imaging (MRI). However, the current evaluation techniques do not offer a method for accurately defining the amount of acetabular rim overcoverage in pincer-type FAI. Several studies have remarked on the particular problems with radiographic evaluation, including beam divergence, difficulty with defining the acetabular rim, and pelvic tilt. Some studies have proposed methods to mitigate these issues; however, radiographic analysis still relies on projected and distorted images, making it difficult to acquire an accurate quantitative estimate of the amount of crossover. We propose a technique that utilises computed tomography (CT) data to accurately quantify the amount of acetabular crossover while accounting for known diagnostic problems, specifically pelvic tilt.

This work describes a novel method that utilises CT data of a patient's afflicted hip joint region to assess the amount of acetabular overcoverage due to pincer deformity. The amount of overcoverage was assessed using a spline curve defined through the segmentation of the acetabular rim from CT data. To mitigate pelvic tilt, the user selected points to define both the pubic symphysis and the promontory in a lateral digitally reconstructed radiograph. The algorithm corrected the pelvic tilt by adjusting to a defined neutral position (in our case, a 60°), and the user adjusted for slight rotation differences ensuring there was a vertical line connecting the symphysis and the sacrococcygeal joint.

After successfully repositioning the pelvis, the algorithm computed the amount of acetabular overcoverage. The algorithm identified the superolateral point of the acetabulum and the most inferior points of the anterior and posterior rim. A line, the mid-acetabular axis, was constructed between the superolateral point and the midpoint of the most inferior points on the anterior and posterior rims; the mid-acetabular axis was extended anterior and posterior to create a plane. Crossover occurred when the anterior rim of the acetabulum intersected this plane. If an intersection occurred, the algorithm measured the length of the mid-acetabular axis, and the length and width of the section representing overcoverage. These points were then projected onto anteroposterior DRRs and again measured to generate a basis of comparison.

We tested our method on four cadaveric specimens to analyze the relationship between radiographic assessment and our technique. We simulated varying degrees of impingement in the cadavers by increasing the amount of pelvic tilt and defining that as the neutral position for a given trial. Moreover, we assessed interobserver variability in repositioning the pelvis as to the effect this would have on the final measurement of crossover length and width.

The software achieved consistent, quantitative measurements of the amount of acetabular overcoverage due to pincer deformity. When compared with conventional radiographic measurements for crossover, there was a significant different between the two modalities. Specifically, both the ratios of crossover length to acetabular length and crossover width to crossover length were less using the CT-based approach (p < 0.001). Moreover, there were no significant differences between observers using our approach.

The proposed technique can form the basis for a new way to diagnosis and measure acetabular overcoverage resulting in pincer impingement. This computational method can help clinicians to accurately correct for tilt and rotation, and subsequently provide consistent, quantitative measurement of acetabular overcoverage.

Aims

Falls are a common occurrence among hospital inpatients and can lead to injury, prolonged hospitalisation and delayed rehabilitation. There is major economic burden associated with this. Post operative orthopaedic patients have certain risk factors that predispose them to falls including decreased mobility, use of opioids and, in some cases, history of previous falls.

The “Wallis” implant is indicated to stabilize symptomatic degenerative lumbar spine segments, relieving low back pain related to instability and thus delaying the need for irreversible, more invasive surgical management. The purpose of this study was to provide the first objective clinical evaluation of the “Wallis” lumbar dynamic stabilisation system.

An independent prospective observational study was carried out utlising SF-36, Oswestry Disability Index (ODI) and visual analogue pain scores (VAS). Surgical pathologies in which this technique was used, the intra-operative and post-operative complications and length of post-op stay were recorded. 102 patients underwent Wallis insertion between June 2007- May 2009, Median age 51.5 (range 28-108). 94% of patients completed questionnaires and were followed up at 3, 6 and 12 month time points. ODI scores decreased from pre-op 39 to 27 at twelve months (p<.0016). VAS back pain scores decreased 59 to 36 (p<0.0001). Leg scores decreased 50 to 39 (p<0.0002). SF 36 scores improved significantly, physical functioning 46 to 59, physical health 30 to 54 and social functioning 47 to 68. 50% of patients believed their health to be better 12 months post-op. Pre-operatively 28% of patients were employed and working with 26% off work due to back problems. This rate increased steadily with 42% employed at 12 months. Two implants were removed, one due to non-benefit with subsequent arthrodesis and one due to infection. One superficial wound infection occurred.

The Wallis dynamic stabilization system provides a superficial and easily reversible surgical procedure with a lower complication rate than conventional athrodesis. Used in patients with painful degenerative lumbar conditions their quality of life objectively approached values of the age- and gender-matched general population.

Adequate pain control is important in allowing early participation in physical therapy after total joint replacement. Opioidanalgesics often cause side effects that limit physical therapy. Therefore, adequate pain relief with reduced narcotics opioids should speed recovery.

Purpose: To determine whether postoperative acupuncture would reduce narcotic usage and improve physical therapy after total joint replacement.

Total knee (TKR) and total hip replacement (THR)patients who received acupuncture on POD 1–3 or did not receive acupuncture were prospectively followed. Postoperative usage of patient controlled analgesia (PCA, normalized to intravenous morphine) and oral and parenteral opioids (normalized to oral immediate release morphine) were measured. Verbal analog pain scores, performance in physical therapy, length of stay(LOS) and location of discharge were recorded.

After TKR, there was no difference in pain scores in either group (acupuncture n=23, non-acupuncture n=25). PCA usage was 58% less in the acupuncture group for the entire hospital stay (p< 0.05). 74% of acupuncture patients and 36% of non-acupuncture patients did not require PCA after POD 2 (p< 0.05). The amount of additional narcotics was 58% less(p< 0.05) for the acupuncture group. Walking distance was greater in the acupuncture group by greater than 40% (p< 0.05) on any day after surgery.43% of the acupuncture patients and 24% of the non-acupuncture patients went home. There was no significant difference in knee flexion or LOS. After THA, the acupuncture group (n=7) used 54% less PCA (p< 0.05), used 96% less additional narcotic, and had 36–83% greater walking distance on any POD than-non-acupuncture group (n=7). Location of discharge and LOS was the same in both groups. There were no complications related to acupuncture in any patient.

Acupuncture is a safe and effective adjunct to traditional methods of postoperative pain management after total hip and total knee replacement.