We investigated a new intramedullary locking nail that allows the distal interlocking screws to be locked to the nail. We compared fixation using this new implant with fixation using either a conventional nail or a locking plate in a laboratory simulation of an osteoporotic fracture of the distal femur. A total of 15 human cadaver femora were used to simulate an AO 33-A3 fracture pattern. Paired specimens compared fixation using either a locking or non-locking retrograde nail, and using either a locking retrograde nail or a locking plate. The constructs underwent cyclical loading to simulate single-leg stance up to 125 000 cycles. Axial and torsional stiffness and displacement, cycles to failure and modes of failure were recorded for each specimen. When compared with locking plate constructs, locking nail constructs had significantly longer mean fatigue life (75 800 cycles (sd 33 900) vs 12 800 cycles (sd 6100); p = 0.007) and mean axial stiffness (220 N/mm (sd 80) vs 70 N/mm (sd 18); p = 0.005), but lower mean torsional stiffness (2.5 Nm/° (sd 0.9) vs 5.1 Nm/° (sd 1.5); p = 0.008). In addition, in the nail group the mode of failure was either cut-out of the distal screws or breakage of nails, and in the locking plate group breakage of the plate was always the mode of failure. Locking nail constructs had significantly longer mean fatigue life than non-locking nail constructs (78 900 cycles (sd 25 600) vs 52 400 cycles (sd 22 500); p = 0.04).

The new locking retrograde femoral nail showed better stiffness and fatigue life than locking plates, and superior fatigue life to non-locking nails, which may be advantageous in elderly patients.

Cite this article: Bone Joint J 2014;96-B:114–21.

Achieving the correct inclination angle for the acetabular component in total hip arthroplasty (THR) can be technically challenging. The aim of this study is to validate the use of a simple, laser-guided system to address the acetabular cup inclination angle intraoperatively and quantify its accuracy and repeatability across users.

A simple inclinometer system was manufactured, consisting of a laser that snaps into both the inclinometer and the handle of a standard trial cup impacter. The system functions as follows:

desired inclination angle is set on the inclinometer,

A validation study was performed on this system using intact cadavers (N=4). A THR-specific. Trial acetabular components were installed unilaterally in each donor using both the laser inclinometer system with an in-line mounted intraoperative navigation system (NaviVision, Vector Vision Hip 3.1, BrainLab) serving as the measurement standard. Three orthopaedic surgeons participated in the study, two experienced with the device (“experts”) and one “novice”, and each surgeon performed two sequential validation experiments:

10 trials at a set device inclination angle, and

Using the laser-guided system, the inclination angle of the trial cup deviated from the desired orientation by 1.1±0.9° (mean st. dev; range: 0–3°) for all specimens across all operators. The corresponding error in anteversion angle was 1.4±1.3° (range: 0–5°). There was no difference in inclination angle between expert and novice surgeons (1.0±0.8° versus 1.1±1.2°, respectively; p> 0.10 for unpaired t-test). To set the desired inclination angle on the trial cup, original and final laser target positions were within 4.1±2.5 cm at 1 m screen placement.

Results suggest that the laser-guided system has sufficient accuracy and repeatability for use intra-operatively. Inclination angles differed from prescribed angles by 1° on average, and malalignment in anteversion was subclinical, ≤5° for all cases. Furthermore, the tolerance for laser re-alignment sufficiently large (5–10 cm) to make the device functional intraoperatively. Future work will focus on expanding the sample size and correcting simple design limitations in the device.

While the early period of distraction osteogenesis has been extensively investigated, there are very few data describing the long-term morphology of the regenerate. We performed magnetic resonance scans in ten adults (men age 35+− 11 yr), seven of whom had bone transport for an iatrogenic osseous defect while further three had tibial lengthening for limb length discrepancy. Follow-up ranged between 14 and 43 months (mean : 28 + − 10 months) following the removal of the external fixator. The perimeter, cross- sectional area, volume and the mean signal intensity was calculated from the obtained T1 weighted axial images. Values were compared with the contralateral tibia that acted as control. All cases that had bone transport increased the volume of the tibia from 15.3% up to 50.8%. The regenerated segment was noted to have expanded significantly (p< 0.0001) in all cases. Mean signal intensity in the regenerate decreased in seven cases significantly (p< 0.0001) suggesting increase content of unhydrated tissue such as bone and collagen. The cross-sectional surface of the transported segment was increased in all cases (p< 0.008). Finally in cases that underwent bone transport, the docking site was noted to be obstructed by unhydrated tissue. Contrary to previous claims, the post-distraction osteogenesis tibia is far from normal, consisting of areas with potentially different biomechanical properties. Recognition of these changes is essential not only for appropriate pre-operative counselling but also for considering treatment modalities in case of a fracture.

Background: By the end of the current Bone and Joint Decade (2000–2010) the World Health Organisation predicts that 55% of post-menopausal women will have osteoporosis, as defined by fragility fracture and / or BMD. Volume aside, fragility fractures also represent a significant technical challenge in operative care. Current aggressive medical management is aimed to minimize the resource impact of this pandemic.

Study Design: This prospective study of 3000 consecutive fractures treated in a Level 1 trauma unit identified 977 fragility fractures requiring operative management, 803 of which were in patients over the age of 65 years. In every case the GP was informed of the diagnosis of osteoporosis and appropriate recommendations were made regarding medical management. We present the demographic features of this population and the resource impact of their management. We also examine the outcome of our efforts to improve care of the elderly with osteoporotic fractures, as all GP’s were contacted 6 months following discharge to determine the uptake of medical treatment as recommended.

Materials and Methods: Our computerized operative database was utilized to prospectively collect demographic and operative data on all 977 patients. All medical charts were examined to identify medications on admission, GP contact details and other relevant information. GP’s were contacted by telephone and post to determine patient 6-month mortality and the uptake in the use of recommended medication. Data represents the mean ± SD.

Results: Of the 803 patients over the age of 65 years, the average age was 80.5 ± 7.5 years, with a 75% female preponderance. 14% of these had had a previous wrist or vertebral insufficiency fracture, while 2.2% had a previous contralateral hip fracture. Hip fractures accounted for 70% (566 patients) of fragility fractures with 25% AMP, 24% Bipolar, 51% DHS. There were 121 wrist fractures. On admission 23% of hip fracture patients were resident in a Nursing Home. Despite the relatively large number with previous fracture (16.2%) only 3.4% were taking calcium / vitamin D supplementation while only 2.1% were on anti-resorptive therapy, eg a bisphosphonate. The median interval between admission and operation was 1 calendar day with a range of 1–10 days. 57% of all cases were performed outside of routine trauma lists. The average length of stay for this hip fracture population was 11.5 days with a further 16.5 days spent at a step down facility. Only 14.8% went directly home. Of 240 GP’s contacted, 74% replied resulting in complete follow-up data on 730 patients. The inpatient mortality rate was 5.8% while that at 6 months follow up was 19%. By this time 54% of hip fracture patients were living in Nursing Homes. The number of patients taking only calcium / vitamin D was 4%, a bisphosphonate alone 6%, while the use of both had risen dramatically to 16%.

Conclusions: To our knowledge this is the largest reported study documenting the epidemiology, demography and short-term follow-up of hip fractures in an elderly Irish population. Such data is essential to appropriately plan for the impending national health crisis consequent to the predicted dramatic rise in the elderly population with bone fragility. In a short time, we have achieved significant success in improving awareness and treatment of osteoporosis in the elderly following hip fracture.

Magnetic resonance imaging (MRI) was used to compare the appearance of the spine in 20 adolescents with proven symptomatic intervertebral disc herniations with that in 20 asymptomatic patients who acted as controls. Abnormality in the signal from the nucleus pulposus of one or more discs was present in all patients, while only four of the 20 controls had any abnormal signals. In all the patients the symptomatic disc produced an abnormal signal and in most a herniated fragment of the nucleus pulposus was identified. Fifteen of the 20 patients had multiple-disc abnormality: six had three abnormal discs and nine had two. This suggests there was an underlying diathesis in patients who later developed disc herniation.

Magnetic resonance imaging (MRI) of the spine produces images which reflect the chemical composition of the intervertebral disc. We have conducted a prospective study of the serial changes in the MRI appearance of the intervertebral disc after chemonucleolysis with the enzyme chymopapain. Fourteen patients were studied after single-level chemonucleolysis and the results compared with a control group of 17 discs in six patients who had diagnostic discography without enzyme insertion. A consistent pattern of gradual loss of signal from the nucleus pulposus culminating in complete loss of nuclear signal was seen in all cases after chemonucleolysis. Chymopapain therefore produced MRI changes analogous with premature gross disc degeneration. The rate at which this occurred varied; complete loss of signal took at least six weeks. Transitory minor end-plate changes were present in five patients, probably representing a mild chemical discitis. No similar changes were seen in the discography group.

The lumbar spines of 22 patients were examined for disc degeneration by magnetic resonance imaging (MRI) and by discography. The results from 50 intervertebral discs visualised by both techniques were independently assessed and graded on a five-point scale from normality to gross degeneration and then compared. In 44 discs the results agreed. Of the six discs which gave differing results, four discrepancies were due to observer error and two to incorrect placement of the discographic needle. MRI was shown to be more accurate than discography in the diagnosis of disc degeneration. It has several major advantages, which should make it the investigation of choice.