Introduction

The Te Whatu Ora Southern catchment area covers the largest geographical region in New Zealand (over 62,000 km2) creating logistical challenges in providing timely access to emergency neck of femur (NOF) fracture surgery. Current Australian and New Zealand guidelines recommend that NoF surgery be performed within 48 hours of presentation. The purpose of this study was to compare the outcomes for patients with NoF fractures who present directly to a referral hospital (Southland Hospital) compared to those are transferred from rural peripheral centres.

The purpose of this study was to determine whether there have been changes in the complexity of femoral fragility fractures presenting to our Dunedin Orthopaedic Department, New Zealand, over a period of ten years.

Patients over the age of 60 presenting with femoral fragility fractures to Dunedin Hospital in 2009 −10 (335 fractures) were compared with respect to demographic data, incidence rates, fracture classification and treatment details to the period 2018-19 (311 fractures). Pathological and high velocity fractures were excluded.

The gender proportion and average age (83.1 vs 83.0 years) was unchanged. The overall incidence of femoral fractures in people over 60 years in our region fell by 27% (p<0.001). Intracapsular fractures (31 B1 and B2) fell by 29% (p=0.03) and stable trochanteric fractures by 56% (p<0.001). The incidence of unstable trochanteric fractures (31A2 and 31A3) increased by 84.5% from 3.5 to 6.4/10,000 over 60 years (p = 0.04). The proportion of trochanteric fractures treated with an intramedullary (IM) nail increased from 8% to 37% (p <0.001). Fewer intracapsular fractures were treated by internal fixation (p<0.001) and the rate of acute total hip joint replacements increased from 13 to 21% (p=0.07). The incidence of femoral shaft fractures did not change significantly with periprosthetic fractures comprising 70% in both cohorts.

While there has been little difference in the numbers there has been a decrease in the incidence of femoral fragility fractures likely due to the increasing use of bisphosphonates. However, the incidence of unstable trochanteric fractures is increasing. This has led to the increased use of IM nails which are increasingly used for stable fractures as well.

The increasing complexity of femoral fragility fractures is likely to have an impact on implant use, theatre time and cost.

Imageless computer navigation systems have the potential to improve acetabular cup position in total hip arthroplasty (THA), thereby reducing the risk of revision surgery. This study aimed to evaluate the accuracy of three alternate registration planes in the supine surgical position generated using imageless navigation for patients undergoing THA via the direct anterior approach (DAA).

Fifty-one participants who underwent a primary THA for osteoarthritis were assessed in the supine position using both optical and inertial sensor imageless navigation systems. Three registration planes were recorded: the anterior pelvic plane (APP) method, the anterior superior iliac spines (ASIS) functional method, and the Table Tilt (TT) functional method. Post-operative acetabular cup position was assessed using CT scans and converted to radiographic inclination and anteversion. Two repeated measures analysis of variance (ANOVA) and Bland-Altman plots were used to assess errors and agreement of the final cup position.

For inclination, the mean absolute error was lower using the TT functional method (2.4°±1.7°) than the ASIS functional method (2.8°±1.7°, ρ = .17), and the ASIS anatomic method (3.7°±2.1, ρ < .001). For anteversion, the mean absolute error was significantly lower for the TT functional method (2.4°±1.8°) than the ASIS functional method (3.9°±3.2°, ρ = .005), and the ASIS anatomic method (9.1°±6.2°, ρ < .001). All measurements were within ± 10° for the TT method, but not the ASIS functional or APP methods.

A functional registration plane is preferable to an anatomic reference plane to measure intra-operative acetabular cup inclination and anteversion accurately. Accuracy may be further improved by registering patient location using their position on the operating table rather than anatomic landmarks, particularly if a tighter target window of ± 5° is desired.

Introduction

Component positioning is of great importance in total hip arthroplasty (THA) and navigation systems can help guide surgeons in the optimal placement of the implants. We report on a newly developed navigation system which employs an inertial measurement unit (IMU) to measure acetabular cup inclination and anteversion.

The pelvis is known to undergo significant movement during Total Hip Replacement (THR). We developed a 4D-tracking device employing an inertial measurement unit (IMU) to track changes in pelvic orientation during THR.

The IMU was mounted on the iliac crest in 39 cases with tracking initiated at the commencement of surgery and digital logging of significant intra-operative milestones (i.e. acetabular impaction). The system was validated by videoing a select number of cases and the 4D model linked in real-time. Data were processed using a custom Java-based infrastructure to calculate roll (left/right) and tilt (flexion/extension).

19 patients underwent direct anterior approach (DAA) and 20 posterior approach (PA). Comparing DAA to PA, at acetabular impaction there was mean pelvic roll seen of 3.7°(range 0.5–10.1°) in the DAA group, and 5.6°(range 0.1–16.2°) in the PA group. Mean tilt in the DAA group was 3.7°(range: 0.2–7.1°) and in the PA group was 1.7°(range: 0.2–4.3°).

Mean BMI in the DAA group was 25.2(range: 18.4–34.2) and 29.1(range: 21.5–42.4). There was no direct correlation between BMI and the amount of roll or tilt recorded for individual patients.

The IMU tracking device provided a useful and real-time method of assessing pelvic orientation during THR via both the DAA and posterior approach. Specific variations in tilt and roll are consistent with previous literature. Significant variation in the pattern of pelvic movement was noted to be dependent on the approach and the position of the patient on the operating table.

Carpal tunnel syndrome (CTS) is said to be a condition of middle-aged women. Our experience is that it more commonly occurs in older people and also in a younger working population. The aim of this study is to describe the epidemiology of CTS requiring carpal tunnel decompression (CTD).

Over a 10.5 year period 3073 CTD were performed on 2309 patients aged 15 – 93 years. This included all public, private and ACC funded cases in our region. During this period we had no restriction to access to CTD as all publicly funded cases were performed under local anaesthetic in a day surgery unit. Neurophysiological studies were performed pre-operatively by the same neurophysiologist. Population data from the national census (2006) was used to calculate the annual incidence of patients requiring CTD for each 5 year age band.

There were 1418 females (61.4%) and 891 males (38.6 %). In contrast females comprised 116 of 306 (37.8%) patients who had their surgery funded by ACC. The mean age at surgery was 45 years for ACC cases compared with 56 years for non-ACC funded cases. The incidence of males having surgery funded by ACC was 1.7 times higher than females.

There was a biphasic pattern in females with an incidence of 3.0/1000 at age 50–54 years, and a second higher peak of 3.1 to 3.4/1000 from 70 to 5 years. Males had a linear increase in incidence peaking at 3.1/1000 for age 65–69 years declining slightly to 2.8/1000 for age 70–85 years. The incidence was significantly higher in females than males overall (1.8 v 1.1/1000) and in patients under 65 years (1.4 v 0.8/1000). In patients over 65 years there was no significant difference in incidence (female 2.8, male 2.5/1000).

Within our region, the incidence of surgically treated carpal tunnel syndrome increases with age. The highest rates are seen over the age of 70 in women and 65 years in men with no significant difference in rates between men or women over 65 years.

Tibial eminence fractures were historically thought of as a condition of skeletal immaturity. Increasingly this injury has been recognized in adults.

The aim was to report on the demographics, mechanism, treatment and outcomes of this injury in adult and paediatric patients.

A retrospective review of all patients presenting to Dunedin Hospital, for management of a displaced tibial eminence fracture, between 1989 and 2009.

19 cases were identified, 10 skeletally mature and 9 skeletally immature. Alpine skiing with a forced flexion and rotation injury accounted for 7 cases, primarily adult females (5 cases). A hyper-extension and rotation injury accounted for 7 cases, primarily in skeletally immature males (4 cases), while direct trauma accounted for 5 cases, primarily males (4 cases).

Associated injuries were more commonly seen in adults and those with high energy trauma. Stiffness was the most common complication (10 cases). Tibial spine fractures are more common in adults than previously thought. Female skiers appear to be a group at particular risk. Our most common complication was stiffness. Early range of motion is essential to reduce the problem of stiffness and extension impingement. Laxity is an infrequent problem in adults and children.

Purpose

Retrospective review of fusion rates using Grafton DBM/allografts only in AIS.

Introduction/aims

Carpal tunnel decompression is common at the world's largest lamb processing plant. The purpose of this study was to establish whether lamb boning caused carpal tunnel syndrome, whether expeditious rehabilitation was possible and current New Zealand Orthopaedic practice.

This study aims to evaluate the accuracy of sheer off self limiting screw drivers and to assess repeatability with age.

It has been reported that overzealous tightening of halo pins is associated with co-morbidity. Our unit has recently received a tertiary referral where the patient over tightened a pin leading to intracranial haematoma, hence our interest in this subject. The torque produced by six new and nine old screw drivers was tested using an Avery Torque Gauge and a Picotech data recorder. These devices are designed to produce a torque of 0.68 Nm, any greater than this is potentially hazardous. Accepted error for each device was +/− 10%. The average torque produced by the new screw drivers was 0.56 Nm with a range of 0.35–0.64 Nm (SD 0.120). The older screw drivers produced an average torque of 0.67 Nm ranging from 0.52–0.85 Nm (SD 0.123).

In conclusion, sheer off self limiting screw drivers are not accurate devices. The older devices are more likely to produce a torque exceeding a safe range and therefore we would recommend the use of new devices only.

Ethics approval: none audit.

Interest statement: none local grant.

Introduction: Inaccuracies in kinematic data recording due to skin movement artefact are inherent with motion analysis. Image registration techniques have been used extensively to measure joint kinematics more accurately. The aim of this study was to assess the feasibility of using MRI for creating 3D models and to quantify errors in data collection methods by comparing kinematics computed from motion analysis and image registration.

Methodology : 5 healthy and 5 TKR knees were examined for a step up/down task using dynamic fluoroscopy and motion capture. MRI scans of the knee, femur and tibia were performed on the healthy subjects and were subsequently segmented using ScanIP(Simpleware) to produce 3D bone models. Registration of the models produced from fine and coarse scan data was used to produce bony axes for the femoral and tibial models. Tibial and femoral component CAD models were obtained for the TKR patients. The 3D knee solid models and the TKR CAD models were then registered to a series of frames from the 2D fluoroscopic image data (Figure 1) obtained for the 10 subjects, using KneeTrack(S. Banks, Florida) to produce kinematic waveforms. The same subjects were also recorded whilst performing the same action, using a Qualisys (Sweden) motion capture system with a pointer and marker cluster-based technique developed to quantify the knee kinematics.

Results: The motion analysis method measured significantly larger frontal and transverse knee rotations and significantly larger translations than the image registration method.

Conclusion: The study demonstrated that MRI, rather than CT scan, can be used as a non-invasive tool for developing segmented 3D bone models, thus avoiding highly invasive CT scanning on healthy volunteers. It describes an application of combining fine and coarse scan models to establish anatomical or mechanical axes within the bones for use with kinematic modeling software. It also demonstrates a method to investigate errors associated with measuring knee kinematics.

In January 2000 we introduced identical guidelines for the more rapid rehabilitation of Achilles tendon ruptures, whether treated operatively or non-operatively. A relaxed equinus cast was used to four weeks, then a CAM walker to eight weeks with supervised mobilisation. The aims of this study were to compare the outcomes of the operative and non-operative groups treated with the same rehabilitation program and audit the effectiveness of these guidelines.

The audit was retrospective from January 2000 till January 2008. The patients were identified from the Emergency Department admissions database, the hospital clinical coding system, the department’s surgical audit data and the hospital physiotherapy appointment system. The audit system was used to identify patients that had complications of their operative treatment, re-ruptures or readmissions. This study focused on the end points of re-rupture, readmission, complications including wound complications and infection.

Five hundred and eighty seven presentations were recorded as Achilles tendon injuries. One hundred and eighty patients were treated operatively and 407 patients were treated conservatively. Seventy five patients (42%) treated operatively and 126 patients (30%) of the non-operative group were rehabilitated in our hospital physiotherapy department. The remaining 386 patients (65.7% of all patients) received physiotherapy elsewhere or did not attend for further treatment. In the operative group there were two re-ruptures (1.1%) both treated in our hospital physiotherapy department. There were 2 wound complications (1.1%), one requiring re-operation. In the non operative group there were 15 re-ruptures (3.7%). Of these three had attended the hospital physiotherapy department (rerupture rate of 2.4%) In the non-operative group treated elsewhere there were 12 re-ruptures from 281 patients (4.2%).

Comparable results were found between operative and non-operative treatment when combined with close physiotherapy guidance. Non-operatively treated patients treated in the community may have higher re-rupture rates. The results are comparable to those in the literature suggesting that the guidelines are effective.

The use of MRI scanning has been described after open reduction of the hip in DDH to check hip position but has not previously been reported after open reduction with femoral osteotomy and the use of metalwork. We performed a prospective study utilising MRI to document the adequacy of reduction.

An MRI scan was performed on the second postoperative day in order to confirm the satisfactory reduction of the hip following surgery. Previously a CT scan was performed.

10 consecutive cases were scanned and all gave diagnostic information of satisfactory reduction. Sedation was not required. The mean scanning time was 3 minute 45 seconds and the total time in the MRI suite ranged from 7 to 10 minutes.

Satisfactory images, the lack of need of sedation, comparable time and cost to CT scanning and most importantly the lack of exposure of the child to ionising radiation make MRI a most appealing method of imaging. We therefore recommend it as the investigation of choice in this patient group.

Demographic data reviewed included gender, MP at time of primary surgery, GMFCS level, age at time of surgery, type of adductor release procedure performed, and experience of surgeon.

Outcome variables assessed were type of subsequent failure, time of failure after primary procedure, and length of follow-up.

Three hundred and thirty children underwent hip adductor surgery. The number of children per GMFCS Level was 33 Level II, 55 level III, 103 level IV, and 139 level V. The average age at time of primary surgery was 4.19 years, mean MP at time of primary surgery 43.16%, and mean length of post-operative follow-up was 7.10 years.

Eighty two children had adductor longus and gracilis lengthening alone, 97 also had an iliopsoas release, 97 had psoas tenotomy and phenolisation of the obturator nerve, and 54 had a psoas tenotomy and neurectomy of the anterior branch of the obturator nerve (in addition to longus & gracilis lengthening).

At time of audit 106 children did not require further surgery (‘surgery success’ of 32%). Thirty one were in children of GMFCS level II (94%), 27 level III (49%), 28 level IV (27%), and 20 level V (14%).

A Cox proportional hazards survivorship analysis was constructed to chart the time course of progression to further surgery over time to reveal statistically significant ‘surgery success’ rates according to GMFCS. Differences in the success rates according to GMFCS become more apparent beyond 3 years post-surgery.

The most important determinant for predicting the success of hip adductor surgery in preventing hip displacement is GMFCS at the time of primary surgery. Current treatment strategies need to be re-evaluated with the context of undertaking long-term post-operative follow up, particularly for children GMFCS levels VI and V.

In a high-risk technically advanced speciality like spine surgery, detailed information about all aspects of possible complications could be frightening for the patients, and thereby increase anxiety and distress. Therefore, aim of this study was to

Analyze written evidence of the consenting procedure pertaining to (a) nature of operation (b) benefits intended as a result of the operation (c) risks specific to the particular type of operation (c) general risks of spine surgery and anaestheia.

Methods: 70 adult elective, consecutive patients who had been listed for Lumbar discectomy /decompression surgery were chosen. The patients were presented with questionnaire of broad-based and open-ended questions designed to elicit theirs views in each of the following areas: expectation, knowledge of risks and alternatives, and personal attitude to information and satisfaction.

The study had a non-randomized design and patients divided into TWO groups Group A and group B.

The patients in the group A received standard information and were consented in a routine way without being given written proforma with all complications. The patients in the group B were given the same information as patients in the control group, with written information about common and rare complications. Patients in both groups were assessed on an ‘impact of events scale’ and hospital anxiety and depression scale immediately before ad after the consent process and again after surgery when they were discharged from the hospital.

For comparison of the proportion of Yes and No answers in 2 groups, Fisher’s exact test was used, and for comparison of more than 2 groups, the Chi-square test was used. For graded answers and other ordinal scales, the Mann–Whitney U-test was used for comparison of 2 groups and the Kruskal–Wallis test for comparison of more than 2 groups. Spearman’s test was used when assessing the correlation between 2 variables measured on an ordinal scale.

Results: Many patients (71%) agreed that the consent form made clear what was going to happen to them, and 77%) reported that it made them aware of the risks of the operation they were to undergo. Over a third (36%) saw it as a safeguard against mixups in the operating theatre. Few patients’ decision to accept surgery appeared to depend on risk information; 8% of patients said that they might have changed their decision, had they been advised of the risks of permanent stroke and myocardial infarction. However, 92% were clear that their decision to accept treatment would not have altered. The women in the group B had symptoms of definite anxiety to a significantly higher degree than the men before the operation. Post-operatively, patients receiving extended information were significantly more satisfied with both the written and oral information about common and rare complications than patients in the control group There were no statistically significant differences between the groups for anxiety or depression, as measured by the HADS, either before or after the operation between Group A and B. Provision of extended information describing most of the possible complications did not have any negative effects on the patients. The patients receiving the extended information were more satisfied and experienced to a higher degree that they could discuss alternative treatment methods with the surgeon. Discussion: Provision of extended information describing most of the possible complications did not have any negative effects on the patients. “Ignorance is bliss” may prove to be an excellent preoperative strategy for patients when outcome is good but detrimental to long term adjustment where significant postoperative complications arise. This raises the possibility that a separate consent could be used where these risks are pre-printed and explained in vocabulary easily understood by patients. The added advantages of this form would be less confusion for the patient and there would be written evidence that patients had understood each of the major risks involved with the proposed procedure. This proposed consent form would also reduce the chance that important risks and complications are omitted when consent is being taken, as well as tackling the issue of variability of experience or lack of knowledge by the person obtaining consent.

Aim: To determine the clinical improvement and the radiological time to fusion as well as correction of the lordosis angle in patients undergoing anterior cervical interbody fusion with the use of a silicate substituted calcium phosphate ceramic (Si-CaP) (Actifuse™ Synthetic Bone Graft, ApaTech, Ltd., Elstree, UK) as the bone graft substitute in the cage.

Design: We conducted a prospective clinical and radiological study to evaluate the use of Si-CaP as bone graft substitute in anterior cervical fusion for degenerative cervical spondylosis.

Materials and methods: Thirty patients were selected prospectively by preoperative and postoperative clinical and radiological assessments. All patients were operated on by a single surgeon (D.A.J.). Neck disability index and visual analogue score were used for the clinical assessment. Radiological assessment included improvement in the lordosis angle and time to fusion. Patients were evaluated at three months, six months and one year post-surgery.

Results: At present 14 patients with a total of 19 levels have completed their one year follow-up. The patients had an average of 50.4 years (range 34–69), with ratio of male to female of 6:7. Lordosis angle improved significantly from a mean lordosis angle of 0.31 preoperatively to 4.75 degree postoperatively (p< 0.05). All the levels had fused at the 1 year follow up and there was no radiological evidence of sinkage of the cage.

Conclusion: Substitution of silicate ions into calcium phosphate ceramics has been shown to impart a negative surface charge, leading to greater protein absorption, increased osteoblast proliferation, and higher production of extracellular matrix. Our results show that Si-CaP has excellent clinical performance as a synthetic bone graft in anterior cervical discectomy and fusion. Postoperatively, patients demonstrate a good fusion with an excellent correction and maintenance of the lordosis angle.

Introduction: Loads acting on scoliotic spines are thought to be asymmetrical and involved in progression of the scoliotic deformity. Abnormal loading patterns could lead to changes in bone and disc cell and activity and hence to vertebral body and disc wedging. At present however there are no direct measurements of intradiscal stresses or pressures in scoliotic spines.

Methods: Stress profilometry was used to measure horizontal and vertical stresses at 5mm intervals across 25 intervertebral discs of 7 scoliotic patients during anterior reconstructive surgery. Identical horizontal and vertical stresses for at least two consecutive readings defined a region of hydrostatic pressure. Results were compared with similar stress profiles measured during surgery across 10 discs of 4 spines with no lateral curvature and with data from the literature.

Results: Profiles across scoliotic discs were very different from those measured across normal discs of a similar age. Hydrostatic pressure regions were only seen in 16/25 discs, extended only over a short distance and were displaced towards the convexity. Mean pressures were significantly greater (0.24MPa) than those measured in other anaesthetised patients (< 0.06 MPa). A stress peak in the concave annulus was a common feature (13/25) in scoliotic discs. In 21/25 discs, stresses in the concave annulus were greater than in the convex annulus, indicating asymmetric loading in these anaesthetised, recumbent patients.

Conclusions: Intradiscal pressures and stresses in scoliotic discs are abnormal even in the absence of significant applied load. Disc cells respond to changes in pressure, hydration and deformation by altering matrix synthesis and turnover in vivo and in vitro. Hence, whatever the cause of the abnormal pressures and stresses in the scoliotic discs, if present during daily life, these could lead to disc matrix changes and especially if asymmetrical, to disc wedging and progression of the scoliotic deformity.

Work supported by Fondation Cotrel

Physical activity is a key determinant of bone mass and health, however during adulthood and ageing there appears to be a decrease in the ability to respond positively to exercise which is variable between individuals. While exercise is known to protect against the osteopo-rotic process with modest increases in BMD the exact cellular and molecular responses are poorly understood.

We have studied the effect of mechanical stimulation on bone histomorphometric parameters, osteocyte viability and gene expression in human trabecular bone maintained in a 3D bioreactor.

Trabecular bone cores were prepared from femoral head tissue removed from patients undergoing total hip arthroplasty and maintained in the bioreactor system for 3 (n= 4 patients), 7 (n=5 patients) or 28 days (n=1 patient). Cores (n=3 per patient) were either frozen directly on preparation (T0), placed in the bioreactor system and subjected to Mechanical stimulation (3000 μstrain in jumping exercise waveform repeated at 1Hz for 5 minutes daily) or maintained in the bioreactor system with no mechanical stimulation as control. After the experimental period total cell numbers, cell viability and apoptosis were determined in un-decalcified cryosections at specific distances throughout the bone cores by nuclear staining (DAPI), lactate dehydrogenase activity (LDH) and Nick Translation Assay respectively. Consecutive sections were collected and RNA extracted for gene expression analysis.

Mechanical stimulation was shown to increase Bone Formation Rate (BFR) as determined by Calcein label/ distance to bone surface in the 28 day experiment (BFR mcm/day Control 0.01 ± 0.0035 vs Load 0.055 ± 0.0036 p=0.0022). Expression of bone formation markers such as Alkaline Phosphatase and Collagen Type I was shown to increase in all patients however there was an individual variation in the response of Osteopontin to mechanical stimulation as determined by quantitative real time PCR expression analysis. Numbers of viable osteocytes at T0 varied between individual patients however viability was significantly increased and apoptosis decreased in association with mechanical stimulation compared to control in all patient samples examined (p to 0.021). Our data tend to support animal model findings relating to the osteocyte saving effects of exercise and provide an insight into the molecular detail of the exercise response in human bone.