High posterior tibial slope (PTS) has been recognised as a risk factor for anterior cruciate ligament rupture and graft failure. This prospective randomised study looked at intra-operative findings of concomitant intra-articular meniscal and chondral injuries during a planned ACL reconstruction. Prospective data was collected as part of a randomised trial for ACL reconstruction techniques. Intra-operative data was collected and these findings were compared with the PTS measured on plain radiograph by a single person twice through a standardised technique and intra-observer analysis was performed.Abstract
Introduction
Material and Methods
Density-modulus relationships are often used to map the mechanical properties of bone based on CT- intensity in finite element models (FEMs). Although these relationships are thought to be site-specific, relationships developed for alternative anatomic locations are often used regardless of bone being modeled. Six relationships are commonly used in finite element studies of the shoulder; however, the accuracy of these relationships have yet to be compared. This study compares each of these six relationships ability to predict apparent strain energy density (SEDapp) in trabecular bone cores from the glenoid. Quantitative-CT (QCT) (0.625 mm isotropic voxels), and µ-CT scans (0.032 mm isotropic voxels) were obtained for fourteen cadaveric scapulae (7 male, 7 female). Micro finite element models (µ-FEMs) were created from 98 virtual ‘cores’ using direct conversion to hexahedral elements. Two µ-FEM cases were considered: homogeneous tissue modulus of 20 GPa, and heterogeneous tissue modulus scaled by CT intensity of the µ-CT images (196 models). Each µ- FEM model was compressively loaded to 0.5% apparent strain and apparent strain energy density (SEDapp) was calculated. Additionally, each of the six density-modulus relationships were used to map heterogeneous material properties to co- registered QCT-derived models (588 models in total). The loading and boundary conditions were replicated in the QCT-FEMs and the SEDapp was calculated and compared to the µ-FEM SEDapp. To account for more samples than donors, restricted maximum likelihood estimation (REML) linear regression compared µ-FEM SEDapp and QCT-FEM SEDapp for each relationship.Introduction
Methods
The purpose of this study was to examine five-year outcomes of patients previously enrolled in a non-operative rotator cuff study. Patients with chronic, full-thickness rotator cuff tears (demonstrated on imaging) who were referred to one of two senior shoulder surgeons were enrolled in the study between October 2008 and September 2010. Patients participated in a comprehensive non-operative, home-based treatment program. After three months patients were defined as “successful” or “failed”. “Successful” patients were essentially asymptomatic and did not require surgery. “Failed” patients were symptomatic and consented to surgical repair. All patients were followed up at one year, two years, and five-plus years. Original results of our study showed that 75% of patients were treated successfully with non-operative treatment, while 25% went on to surgery. These numbers were maintained at two-year follow-up (previously reported) and five-year follow-up. At five+ years, 88 patients were contacted for follow-up. Fifty-eight (66%) responded. The non-operative success group had a mean RC-QOL score of 80 (SD 18) at previously reported two-year follow-up. At five-year follow-up this score did not decrease (RCQOL = 82 (SD 16)). Furthermore, between two and five years, only two patients who had previously been defined as “successful” became more symptomatic and underwent surgical rotator cuff repair. From the original cohort of patients, those who failed non-operative treatment and underwent surgical repair had a mean RC-QOL score of 89 (SD 12) at five-year follow-up. The operative and non-operative groups at five-year follow-up were not significantly different (p = 0.07). Non-operative treatment is an effective and lasting option for many patients with a chronic, full-thickness rotator cuff tear. While some may argue that non-operative treatment delays inevitable surgical fixation, our study shows that patients can do extremely well over time.
