Purpose

To describe the implication of Family Physicians (FPs) in the management of osteoporosis revealed by a fragility fracture.

Purpose: A functional centre of rotation (CoR) is often required in biomechanical analysis of the hip or as a landmark in computer guided surgery. It was previously shown that circumduction motions predict a CoR that is inferior and lateral to the geometric centre of the hip bearing surfaces. It is therefore necessary to establish the best method for determining the CoR to improve surgical planning. The objective of this study was to compare the predicted CoR from circumduction and star motions, and to compare these to the geometric centre of the joint.

Method: Eight cadaveric hips from four cadavers were tested. Prior to testing, CT scans of the cadavers were made from the iliac crest to the tibial plateau; the alpha angle for all hips was less than 50° so all hips were considered ‘normal’. Reflective marker arrays were rigidly mounted on the femoral diaphysis and iliac spine using 4mm Steinman pins. A five-camera Vicon system (Oxford, UK) was used to track the motions of the arrays during manipulation of the lower limb. To determine the functional hip centre, trials consisting of five cycles each of circumduction, flexion-extension and abduction-adduction were performed on each lower limb; three trials of each motion were performed. The range of motion was approximately 45° in the coronal and sagittal planes. For the ‘star’ motion, the flexion-extension and abduction-adduction trial data were combined. Following the trials the hip was dissected to expose the articular surfaces of the femoral head and acetabulum. These surfaces were traced using a pointer equipped with reflective markers to determine the geometric centre. To calculate the functional centre, the 3D coordinates of the markers were used to construct a local-to-global 3D transform for each frame throughout the trial. The geometric centre was calculated using a least-squares sphere fit (Gauss-Newton) of the trace data, calculated in the respective local coordinate systems. The coordinates of the functional centres were then transformed to an anatomic coordinate system, using the geometric centre as the origin. All calculations were performed using Matlab (Mathworks, Inc, MA, USA). A t-test was performed in each anatomic direction to detect differences in CoR predicted by the two motions.

Results: Both the circumduction and star motions resulted in a similar CoR. Differences were 0.41±2.25mm in the anterior-posterior direction; 0.09±0.72mm in the superior-inferior direction; and 0.21±0.82mm in the medial-lateral direction, none of which were significant (p> 0.5). The overall mean distance between the CoR predicted by the two motions was 2.0±1.3mm. The functional centre was also found to be lateral and inferior to the geometric centre, and was consistent for each motion. Results for the acetabulum showed similar trends.

Conclusion: This study has shown that circumduction and star motions are equivalent in predicting the hip functional CoR; differences were small compared to the dimensions involved in studies such as gait analyses. However, both motions predicted a CoR that was inferior and lateral to the spherical centre of the femoral head, suggesting that the hip does not act as a true ball-and-socket joint with congruent spherical bearing surfaces. This may have important consequences in studies at the scale of the hip joint, especially for pathological conditions such as femoroacetabular impingement.

Purpose: It is thought that the anterior approach better restores gait mechanics after total hip arthroplasty (THA) being a pure intermuscular/internervous approach. The purpose of this study was to compare three-dimensional (3-D) kinematics and kinetics of THA patients that had an anterior (ANT) vs. a lateral (LAT) approach. It is hypothesized that the ANT group will exhibit fewer differences than the LAT group when compared to a control group (CON).

Method: Fifty-four participants were divided into three groups of 18: ANT (12 women, 6 men; age: 60.9 ± 6.2 yr; BMI: 28.8 ± 4.9 kg/m2), LAT (10 women, 8 men; age: 65.2 ± 6.3 yr; BMI: 27.5 ± 5.1 kg/m2) and CON (9 women, 9 men; age: 63.9 ± 4.4 yr; BMI: 25.4 ± 3.2 kg/ m2). All THA patients had primary unilateral THA due to osteoarthritis and had no other lower-limb pathology. They were evaluated five to 17 months after surgery. 3-D kinematics and kinetics were obtained using a nine-camera motion analysis system and a force platform placed on the first step of a staircase. Each participant performed three trials of stair ascending. A series of one-way ANOVAs were used to compare peak angles, range of motion (ROM), peak resultant joint forces as well as moments and powers of the hip, knee and ankle joints in all three planes.

Results: Most differences occurred during transitions between double- to single-legged stance. Both LAT and ANT groups ascended the staircase with a more abducted hip than the CON group, resulting in reduced hip abduction moment. This could be the result of the implant’s position and its potential abductor lever arm reduction. Both groups also showed reduced peak internal rotation moments. These results have previously been found in THA patients who have been operated through lateral and posterior approaches, and are thought to be caused by hip abductor muscle damage inherent to the surgical approach. However, only the LAT group had lower compression forces at the hip, knee and ankle joints compared to the CON group. This indicates that LAT group uses a strategy that reduces the loading on the operated leg, which may be due to the detachment of the anterior third of the gluteus medius. It could be speculated that the muscle sparing aspect of ANT approach allows patients to load adequately their operated leg, even if their frontal plane kinematics and kinetics are altered.

Conclusion: Some studies have failed to find differences with the anterior approach. However, they have only looked at spatiotemporal gait parameters. 3-D kinematics and kinetics can provide a more detailed assessment of function and detect more subtle differences. In this study, 3-D biomechanical analysis has detected differences in THA patients operated through different surgical approaches during stair ascent. The data obtained showed similar frontal plane kinematics for both groups, but different lower-limb compression forces. This study supports the use of the anterior approach for better restoration of function after total hip arthroplasty.

Purpose: Recognizing Osteoporosis and Its Consequences in Québec revealed that 73% of women 50y and over are not provided anti-fracture therapy following fragility fracture. This study’s objectives were to determine predictors of osteoporosis (OP) diagnosis (DX) and treatment (TX) 6 to 8 months after fragility fracture.

Method: At phase 1, women were recruited at cast or out-patient clinics within 16 weeks post-fracture. Consenting patients answered a short questionnaire classifying them as experiencing a fragility or traumatic fracture; no reference to the association between fracture and OP was made and no investigation or intervention was proposed. At phase 2, 6–8 months post-fracture, the women completed a questionnaire on demographic features, clinical characteristics and risk factors for OP. The DX (informed of OP and/or BMD measurement with diagnosis of OP) and TX (bisphosphonates, raloxifene, nasal calcitonin or teriparatide) rates of OP were determined via this questionnaire. This analysis included only women with a fragility fracture who were not receiving OP TX at phase 1.

Results: Of the 1273 women completing phase 1, 1001 (79%) sustained a fragility fracture; 818 were untreated at phase 1 and completed the phase 2 questionnaire. Overall, 79% of these participants had not received a DX of osteoporosis or were without OP TX at phase 2. The highest rate of DX and TX of OP occurred 0–5 months post-fracture and decreased considerably thereafter. In multivariate analyses, the results of BMD tests before or after the fracture event (p< 0.0001) and mobility problems (p=0.03) were the only variables that influenced the DX of OP. BMD test results were the strongest predictor (p< 0.0001) of TX followed by the fracture site (hip, femur and pelvis; p=0.015) and administration of vitamin D supplements at the time of fracture (p=0.035). No other risk factors for OP significantly influenced the DX or TX rate. No demographic or clinical features or OP risk factors were significantly associated with the decision to refer women for BMD testing post-fracture.

Conclusion: Although fragility fracture represents a greater risk of future fragility fracture than low BMD, physicians based their decision to treat on BMD and not the clinical event (fragility fracture).

Purpose: Only 20% of women presenting with fragility fracture are subsequently investigated for Osteoporosis (OP). Blurred lines of responsibility between the orthopedic surgeons (OS) and the general practitioners may partly explain this situation. OPTIMUS is a 3 year health management program, lead by an OS and a rheumatologist, whose objective is to improve the rate of initiation of and persistence on treatment of OP in patients sustaining a fragility fracture visiting an OS at the Centre hospitalier universitaire de Sherbrooke.

Method: All outpatients aged 50 years and older in which a fragility fracture is suspected by the OS are informed by a nurse practitioner about the OPTIMUS program. The first 200 patients seen at the Hôtel-Dieu site of the CHUS represent the control group. Inpatients with hip fragility fracture are evaluated by a rheumatologist. After signed consent, outpatient participants are randomized to one out of two intervention groups: The Minimal Intervention group includes nurse counseling and written general information transmitted to both patient and treating physician. Same information is given in the Intensive Intervention group. Blood tests and osteodensitometry are also performed and results transmitted to the treating physician along with personalized guidelines for treatment of the patient’s OP. In both interventions, patients are reached by phone at fixed intervals. Additional rounds of intervention are repeated as needed to increase the rates and persistence of appropriate treatment.

Results: Over the first 6 months, the OS team identified 300 patients, 30% of which suffered from hip fracture. Acceptance rates to OPTIMUS management program were close to 95% with direct contact as compared to 50% with delayed phone contact. 5% of outpatients could not name a treating physician and thus had to be seen in rheumatology. The results during the first 18 months of the project will assess the feasibility of OPTIMUS’ interventions.

Conclusion: There is a substantial care gap in the management of OP, despite the availability of diagnostic modalities and effective treatment. Involving orthopedic surgeons as key leaders of a multidisciplinary team implementing a systematic approach to identify patient with OP should help to close this care gap.