A new method of polyethylene wear measurement for analysis of serial radiographs of the same patients over a 10 year period is described.

Eighteen patients with a PCA THJR had serial radiographs performed with a minimum of 8.5 year follow up. A total of 560 A-P and lateral radiographs were analysed.

The graphs of PE wear v time fell into two groups: Group 1 – (7 patients) had accelerated PE wear with eventual development of osteolysis. Group 2 – (11 patients) had PE wear of less than 0.16mm/year and their latest radiograph showed no evidence of osteolysis.

With improved accuracy and elimination of user error, measurement of PE wear may now have the ability to make predictions about the longterm survival of a THJR. Clinical decisions may be able to be made based on individual patient measurements.

Forty six periprosthetic femoral fractures adjacent to a hip prosthesis have been retrospectively reviewed. Follow up included chart and radiograph review, Oxford Hip Score and SF-12 Global Function Score. Fractures were treated with internal fixation or revision arthroplasty without the use of allograft.

All the fractures united and functional outcome was good. The mean Oxford Hip Score was 26 and the SF-12 was 33. Complications were related to the severity of the fracture according to the Vancouver classification.

These results and a review of the literature support the ongoing management of periprosthetic femoral fractures without allograft.

The aim of this study was to document the medium-term results of the use of fluted, tapered, titanium femoral stem in revision total hip arthroplasty.

Seventy patients undergoing total hip revision using a tapered, grid-blasted titanium modular femoral stem were reviewed at a mean follow-up time of 47 months. Femoral defects were classified according to the Pak and Paprosky system, and femoral bone quality was assessed with the Bohm and Bischel system. Clinical function was measured by the Oxford Hip Score. Radiograpic analysis was performed in all cases.

Stems were classified as a failure or re-revision in 4.3% of the cases. Three required reoperation for recurrent dislocation, in each case the femoral component alone had been revised during the most recent revision. The postoperative mean Oxford Hip Score was 20.9. Subsidence of the component was noted in 84% of hips but did not cause a significant problem. Final leg length discrepancy was 5.4mm.

The results of this titanium, tapered, grid-blasted modular stem compares favourably with other revision stems including the Oxford Hip Score compared to the results for revisions recorded in the National Joint Register (Oxford Score 24.3). Although technically demanding this stem offers a very satisfactory solution for revision of total hips in almost all circumstances.

We have correlated the ‘bedding-in’ response (the high femoral head penetration seen in the first two years after operation) with changes in offset and leg length from opposite normal hip.

Fifteen patients with serial x-rays taken in the first 5 years after operation had measurement of PE wear, femoral offset and leg length change from the opposite normal hip.

There was a weak correlation between increasing the leg length and increasing the offset during operation and increased femoral head penetration (‘bedding-in’) seen during the first two years after the operation. There was no correlation between offset and PE wear after two years in the PCA prosthesis.

Increased tissue tension in the first two years caused an increase in femoral head penetration. This effect is not continued beyond two years.

We assessed the functional outcome of fractures of the os calcis a minimum of twenty- four months following injury.

Eighty-three patients with 85 fractures were assessed a minimum of two years following fracture of the os calcis, using a validated functional outcome measure designed specifically for fractures of the os calcis, and an EQ5D. Radiographic analysis of all fractures was performed to attempt to correlate outcome scores with the fracture pattern.

Sixty per cent of the questionnaires were returned completed. Forty percent of the fractures were treated surgically, the remainder with a period of weight relief, followed by physiotherapy and graded weight-bearing. The majority of patients reported a mild hind foot pain (8/10 on a VAS), and all reported some difficulties with walking on uneven terrain. There was no appreciable difference in the outcomes comparing patients treated by open reduction and internal fixation and those treated non-operatively.

This study demonstrates a surprisingly high patient satisfaction rate following fractures of the os calcis whether they are treated operatively or non-operatively. Patients seemed to have compensated for any altered function very well. We were not able to identify specific fracture patterns that were associated with poorer outcomes.

The purpose of this study was to assess the regional variation in the incidence of hip fractures in patients over 65 years. in New Zealand. Data from the National Minimum Data Set (NMDS) for hip fractures from 1 July 1998 to 31 June 2000 was obtained. The data was divided into 21 District Health Board (DHB) regions by mapping from domicile code to DHB. Population of interest as at 30 June 1999 was estimated on the basis of previous census in 1996. The incidence of hip fracture per 100,000 for each region was calculated and divided into age and sex cohorts.

There is a significant difference between DHBs in the sex and age adjusted incidence of hip fractures. The rates ranged from 556 per 100,000 to 838 per 100,00. As expected there was a higher fracture rate in women and the fracture rate increased with age. There was a weak correlation with sunshine hours (p=0.029) with increasing fracture incidence as sunshine hours decrease.

This study demonstrates a large variation in the incidence of hip fractures per DHB region. The cause for this is unclear, but the cost implications are significant. DHB’s with a high incidence of hip fractures in their region may wish to investigate strategies for reducing the incidence.

The aim of this study is to identify specific risk factors for developing haemophilia related orthopaedic complications and to provide a qualitative and quantitative analysis of the orthopaedic management of haemophilia complications.

A postal survey was sent to 48 patients on the Wellington region haemophilia database. The questionnaire covered both qualitative and quantitative questions covering the participants’ current condition and treatment, past and present orthopaedic and non-orthopaedic management, support, education, employment and leisure activities.

Twenty-five patients returned the questionnaire, a response rate of 52%, Most of the participants (68%; 17/25) felt that their education had been compromised as a result of haemophilia complications. Of those participants that were 16 years or older, 68.4% (13/19) felt that their working opportunities had been compromised as a result of haemophilia complications. Despite patients less than 18 years of age receiving prophylactic Factor VIII replacement (n=7) and all patients having Factor VIII available on demand, 18 patients had significant bleeds in the previous 6 months. Most bleeds were into joints, 13 knees, 13 ankles, 12 elbows, 6 shoulders and 3 hips, but a significant number of intra-muscular bleeds (n=22) also occurred. There were 62 painful joints reported by 19 patients, the ankle being most common (n=21), followed by hip (n=13), elbow (n=12), and knee (n=8). Twenty orthopaedic operations were described by 8 patients, mainly knee (n=6) and hip (n=3) replacements, and synovectomies (n=6). Discussion.

Despite good medical management, recurrent joint bleeds are a major problem in haemophilia. Many study patients commented that orthopaedic procedures were not performed readily enough, and that by the time they received their operation, their function had deteriorated significantly.

The purpose of this study was to assess the incidence of pelvic osteolysis following the use of a one piece all polyethylene acetabular component a mean of 9.6 years following implantation. The radiographs of 86 hips followed for a mean of 9.6 years were reviewed. All had had primary total hip arthroplasty using a titanium plasma spray backed all polyethylene acetabular component. Radiographs were assessed for pelvic osteolysis in the three zones described by Charnley and Delee. There was no osteolysis seen in any cup in any of the three zones. There were no loose cups and no obvious cup migration. This acetabular component shows superior performance compared with all two pieced components in terms of the development of pelvic osteolysis. The use of two-piece cups should be reviewed.

The purpose of this study was to compare the 2D and 3D linear and volume wear readings of the three most commonly used methods for measuring polyethylene wear: the Livermore, Devane and Martell techniques. Inter-observer variation of measurements using the techniques of Devane and of Martell on conventional radiographs was also performed. The radiographs of 80 patients (mean age 60+/−10 yrs) who had a Harris-Galante I total hip arthroplasty were measured. Nine different reviewers for the Devane technique readings including Dr Devane and eight reviewers for the Martell technique readings including Dr Martell made blinded independent wear observations for each radiograph set. One reviewer measured the 20 annual linear wear rate for all radiograph sets using the 2D Livermore technique. Inter-observer variation as a function of patient, reviewer, and total variation was statistically assessed using variance component analysis. Mean wear measured using the Livermore technique was the same as with the Devane and Martell method, but with a greater variation. Comparison of the Devane and Martell method for patient STD, reviewer STD, error STD (multiple reviews of same radiographs), total STD (randomly picked reviewer), mostly show a mean 50% lower STD with the Devane technique. Correlation (correlation coefficient of two randomly selected reviewers) is significantly better with the Devane technique.

The purpose of the study was to assess the incorporation of defatted, and deproteinated bovine cancellous bone in a sheep bone graft model. Cylindrical defects were created in the femoral condyles of 12 sheep using custom-made trephines. The defect was filled with a cylinder of prepared bovine bone. The removed cylinder of bone was implanted into a defect created in the opposite femoral condlyle. Fluorochrome bone labels were administered over an 8-week period and the sheep sacrificed at 10 weeks. Undecalcified thin bone sections were viewed with a fluorescent microscope.

ln one sheep there was a technical problem leading to unsatisfactory histology. All other sheep showed similar histology. The autograft incorporated rapidly with the graft showing a rim of reactive bone and the graft itself showing rapid laying down of new bone on its surface. The xenograft showed a similar reactive rim of new bone with deposition of new bone throughout the graft and resorption of the graft material.

This study demonstrates that specially prepared bovine cancellous bone can act as a scaffold for the depostion of new bone in a sheep model. The role of this material in humans is to be evaluated.

The purpose of this study was to determine if the incidence of heterotopic ossification following total hip replacement decreases with increasing experience of the surgeon. A comparison of the incidence of heterotopic ossification between 196 patients having primary total hip replacement in 1989–1990 and a second group of 180 patients between 1999–2000 was performed. The surgery was done by one surgeon. Radiographs taken at least six months post operatively were assessed, and graded using both the Hamblen and Brooker classification systems. No patients were given specific prophylaxis. The groups were well matched. There was a statistically significant reduction in the incidence of Grade 2 and 3 heterotopic ossification in the 1999–2000 patient group.

There did not appear to be any identifiable reason for this except increased surgeon experience. The incidence in the 1999–2000 group was well below reported figures from other studies. The incidence of heterotopic ossification following total hip replacement is falling and the fall may be related to improved surgical technique.

The purpose was to define the economic and health costs of waiting for total hip joint replacement surgery. A prospective cohort of 122 patients requiring primary hip arthroplasty (HA) was recruited from four hospitals in the lower North Island. Health related quality of life (HRQL), using self-completed WOMAC questionnaires, was assessed monthly from enrolment pre-operatively to six months post surgery. Monthly cost diaries were used to record medical, personal and other costs. Data was analysed using PC-SAS to test the strength of associations between costs and waiting times, and changes in HRQL pre- and post-surgery.

The mean waiting time was 5.2 months and mean cost of waiting for surgery was $1,376 per person per month (pp pm) with medical, personal and social costs contributing $404, $399, and $573, respectively. Waiting more than 6 months was associated with an increased cost of $730 pp pm for a total cost of $2177 pp pm (p< 0.003). Age was correlated with greater loss of income (< 65 years) (p=0.001) and higher medical costs (< 65 years) (p=0.08). An incremental improvement over time in WOMAC scores post-operatively was identified (p=0.0001). Older age (p=0.01), community services card use (p=0.003) and a greater number of months waiting (p=0.1) were negatively correlated with post-surgical improvement after adjusting for other variables. Longer waits for HA incur greater economic costs and impact on patient recovery. This lends weight to the view that a shorter waiting time for HA significantly reduces costs to individuals and society and improves health outcomes.

The aim of the study was to investigate functional outcomes and perceptions of quality of life in a series of elderly patients who have sustained tibial plateau fractures. A retrospective survey of all patients aged over 60 years who were admitted to Wellington and Hutt hospitals for treatment of a tibial plateau fracture between July 1996 and December 2000 was carried out. Patients were sent the Oxford 12 knee score and the Nottingham Health profile (NHP) by mail. Radiographs were reviewed to confirm fracture type and medical notes reviewed to ascertain treatment. Patients were divided into non-operative (plaster cast or brace; n=8) and operative treatment (open reduction and internal fixation (ORIF) or total knee replacement; n=15) groups.

Of 42 eligible patients, 23 returned completed questionnaires (rr=55%). The mean age of patients was 73.6 years with 16 (69.6%) females and 7 (30.4%) males. Mean time to follow up was 38.7 +/−14.5 months. The mean Oxford 12 knee score was 39.3. The mean NHP-part I scores were 17.6, 8.4, 3.3, 14.4, 2.9, 9.3 for energy level, pain, emotional reaction, sleep, social isolation and physical mobility respectively. 73% of the patients felt that their present state of health was not causing problems with any of the activities mentioned in the NHP-part II.

The perceptions of outcomes of tibial plateau fractures in the elderly after conservative treatment is comparable with operative treatment. The results show Oxford 12 Knee and NHP scores similar to other studies and indicate satisfactory knee function.

There is controversy regarding the best way to manage fit, independent patients with acute hip fractures. The aim of this study was to compare, nationally, the early complication rates of total hip arthroplasty (THA) in those patients with an acute fractured neck of femur (NOF) with a similar group of THA’s performed in patients with a diagnosis of osteoarthritis.

Using the National Hip Joint Register and the New Zealand Health Information Service Database, 200 patients with acute hip fractures undergoing THA were identified and compared to 1102 THA’s performed on osteoarthritis patients. The mortality, revision, dislocation and infection rates were analysed at a minimum of one year.

Acute THA had a 7.5% one-year mortality rate compared with 2.5% in the OA group (p < 0.01). The revision rate was 2.5% vs 1.8% in the acute and OA groups respectively. The dislocation rate was 4.3% for the whole group with a 8.5% for the acute group and 3.5% for the OA group (p< 0.01). In the acute group the dislocation rate using the posterior approach was 17.1 % compared to 3.1% for the lateral approach (p< 0.01).

We conclude that acute THA is a useful procedure in fit patients with a fracture of the neck of the femur but that a posterior approach should be avoided.

Early discharge from hospital has the potential to reduce direct costs, but may result in patients being discharged without adequate preparation for a return to the community. This qualitative study aimed to investigate patient expectations of and satisfaction with in-hospital discharge planning after hip arthroplasty in early and late discharge patient groups. A prospective study of 33 consecutive patients requiring hip arthroplasty were recruited from two tertiary hospitals in the lower North Island. Participants were interviewed using in-depth, semi-structured interviews on the day of discharge from hospital and again four-eight weeks later. Comparative analysis of the interviews from patients in early and late discharge groups was made.

Findings reveal good levels of satisfaction with discharge planning for patients in both early and late discharge groups, facilitated by the opportunity to attend a pre-assessment clinic. Discharge planning was viewed as a partnership between patients and key members of the multi-disciplinary team. While written information provided was timely, restricted opportunity for dialogue with health professionals limited patient knowledge and understanding of recovery. Different needs of participants indicate that discharge planning needs to be tailored and more responsive to individuals. The role of health professionals as a mentor-coach is pivotal. Further interaction from health professionals, as a follow-up to written information provided may be a way to improve the discharge process and lead to more consistent outcomes.

Aim: To examine the effect that a modular, uncemented, fully coated titanium stem (PFM-R, Protek) has on the bone stock of revised femora.

Methods: Forty revision hip arthroplasties between 1997–2000 were performed by one surgeon using the PFM-R revision stem. The patients were assessed radiographically over a two-year follow-up period. The pre-operative radiographs were examined for bone defects according to Paprosky et al., 1987. Serial radiographs taken post-operatively after two days, six weeks, three months, six months, 12 months and 24 months were used to assess signs of fixation, stability and change in the cortices of 16 femoral zones according to criteria set out by Engh et al., 1987. The change in the density of the bone defects identified at the time of surgery was also examined.

Results: The average age of the patients was 65 years. Thirteen revision stems were followed for one year and 13 were followed for two years. Fourteen patients had an incomplete radiographic follow-up. Two type I defects, 23 type II defects and one type III defect were identified. Twenty-one of the 23 type II defects showed evidence of regeneration in the subtrochanteric metaphysis. One revision stem had radiographic evidence of bone resorption proximally though three stems subsided. No stress shielding was seen distally.

Conclusion: At early follow-up the PFM-R appears to be a viable revision femoral implant which facilitates the regeneration of metaphyseal bone stock.

Purpose: To examine the histology of the bone cement interface in a canine total hip model comparing two different cementing techniques.

Methods: Seven adult mongrel dogs underwent staged bilateral total hip replacement, on one side cement was finger packed into the femur, on the opposite side the femoral canal was washed, brushed, distally plugged and pressure injected with cement prior to inserting the femoral component. Sequential flurochrome bone labelling was performed. The dogs were sacrificed up to six months post surgery. Under-calcified sections of the femur were examined by fluorescent microscopy.

Results: Post-operative radiographs showed complete filling of the proximal femur with cement in the pressure injected group, and a relatively thin mantle in the finger packed group. Histology of the finger packed group showed minimal intrusion of cement into the cancellous bed, direct opposition of cement and bone with small areas of fibrous tissue interposition. In the pressure injected group the cement extended to the endosteal cortex, there was no bone necrosis, and the intruded bone underwent remodelling similar to that at the margins.

Conclusions: This study suggests that “third generation” cementing techniques result in greater contact between bone and cement, and may explain the claim that femoral stems in humans inserted using third generation techniques are more durable than those inserted using “first generation” techniques.

Introduction: Ankle fractures are the third most common fracture presenting at public hospitals in New Zealand. There have been few outcome studies following treatment of ankle fractures.

Aim: To identify the relationship between three types of ankle fractures and the functional and quality of life outcomes for patients two years after the injuries.

Methods: Seventy-four patients seen at Wellington Hospital with ankle fractures during 1998 were contacted for the study. Patients had been treated by open reduction and internal fixation, or by the application of a plaster cast with manipulation of the fracture being performed where necessary. Each patient completed an ankle specific Olerud and Molander questionnaire and an EQ5D Quality of Life Outcome measure. All x-rays were analysed and the fractures were classified using the Weber classification.

Results: There were 22 males and 52 females, 11% had Weber type A fractures, 67% had Weber type B, 18% Weber type C and 4% an isolated posterior malleolar fracture. Fifty-one patients underwent surgery. Patients who sustained Weber type A fractures generally recorded good to excellent OMA scores, while those with Weber Band C fractures produced significantly poor results. An analysis of the ankle visual analogue score versus the method of treatment showed that patients who underwent surgery judged their ankle to be less functional than the patients who had non-surgical interventions. The mechanism of injury also correlated with the end result, patients who had injured their ankles during sporting activities scored lower scores than those who had injured their ankles in simple falls. Patients requiring removal of an internal fixation device had a lower OMA score when compared with those who retained their fixation devices in situ.

Conclusions: This long-term out come study indicated that there was significant dysfunction following ankle fractures, with a surprising level of disability following Weber B and C fractures. The results of this study do not indicate better results in those patients who underwent surgery.

Introduction: It is well documented that surgery following hip fractures (#NOF) has accepted failure rates of between four and 33%. An average of 120 patients are admitted to Wellington hospital for #NOF each year.

Aim: We aimed to identify the rate of and reasons for readmission for further surgery within a year of #NOF in patients admitted to Wellington hospital.

Methods: A list of all patients admitted for surgical treatment of hip fractures during 1998 and 1999 was obtained from the hospital database. Demographic data, type of fracture, surgical intervention, readmission for surgery on the same hip and subsequent surgical intervention for each patient were noted.

Results: Of the 209 patients who underwent surgery for 215 fractures, 55% (n=119) sustained subcapital, 43% (n=92) intertrochanteric and 2% (n=4) other fractures. Seven percent (n=15) were readmitted for a second hip operation within twelve months. Eighty percent (n=12) of those who were readmitted had sustained sub-capital fractures. Of those in the readmission group primary surgery comprised ORIF with cannulated screws (40%), compression screw with or without one cannulated screw and plate (40%), hemiarthroplasty (HA) (13%) and total hip arthroplasty (THA) (7%).

For patients who had sustained a subcapital fracture (n=117), 21% (P< 0.05) of those who had been treated with cannulated screws required further surgery compared with 2–14% who had the other types of surgery.

Conclusions: Rates of readmission for further hip surgery following hip fracture in Wellington hospital appear to be in the lower range of those reported elsewhere.

Purpose: To measure quality and quantity of sleep in patients before and after hip arthroplasty.

Methods: A prospective survey where 50 participants were sent a sleep diary, an acti-watch motion-logger, and a 32 item sleep questionnaire. These data were collected at least four weeks prior to and three months after surgery. Data analyses included descriptive statistics and within-subject pre and post surgery comparisons. For the subjective data, comparison was by the McNamar Test for the significance of changes. For the acti-graphy variables, comparison was by mixed model analysis of variance.

Results: Preliminary results indicate that subjective measures of sleep quality improve significantly three months after hip arthroplasty, e.g. patients rated their sleep disturbance due to hip-pain on a scale from 1=never to 4=always. 75% of patients reported an improvement, and 25% reported no change in this variable, post surgery. Acti-graphy measures confirm the overall improvement in sleep quality (for sleep efficiency, (p(f)=0.05) and fragmentation index, (p(f)=0.05), and a reduction in mean activity during sleep (p(f)=0.04). Ongoing analyses are addressing the reliability of subjective measures compared to acti-graphy and why some patients show greater improvement in sleep than others, after hip arthroplasty.

Conclusions: Findings suggest that sleep disturbance occurs as a result of painful osteoarthritis in the hip, and that this can be significantly ameliorated by hip arthroplasty surgery. The expected improvement in quality of life and level of day to day functioning that accompany improved sleep are perhaps an under-rated benefit of this procedure.