Introduction: We aimed to assess a simple radiological method of predicting redisplacement of paediatric forearm fractures. The Cast Index (CI) is the ratio of sagittal to coronal width from the inside edges of the cast at the fracture site. A CI of > 0.7 was used as the standard in predicting fracture redisplacement. The cast index has previously been validated in an experimental study.

Methods: Case records and radiographs of 1001 children who underwent a manipulation under general anaesthesia for a displaced fracture of the distal forearm were studied. Redisplacement was defined as more than 15 degrees of angulation and/or more than 80 percent of translational displacement on check radiographs at 2 weeks. Angulation (in degrees) and translation displacement (in percentage) were measured on the initial and check radiographs. The CI was measured on postoperative radiographs.

Results: Fracture redisplacement was seen in 107 cases at 2 week follow up. Of the 752 patients (75%) with a CI of less than 0.7 the displacement rate was 5.58%. Of the 249 patients (25%) with a CI greater than 0.7 the redisplacement rate was 26%. The CI was significantly higher in the redisplacement group. No statistically significant difference was seen for age, sex or ethnicity. Nor were statistical differences noted in initial angular deformity, initial displacement and seniority of the surgeon. Good intra and inter observer reproducibility was observed. There was no statistical difference in patients with a cast index between 0.7 and 0.8.

Conclusion: The cast index is a simple and reliable radiographic measurement to predict the redisplacement of forearm fractures in children. Previous studies have used a CI of > 0.7 as the predictor of redisplacement although this study suggests a plaster with a CI of < 0.81 is acceptable. A high cast index is associated with redisplacement of fractures and should therefore be considered when moulding casts in distal forearm fractures.

Polyethylene wear and osteolysis continue to be associated with failure of total hip arthroplasty. The advent of highly cross linked polyethylene may potentially reduce such wear.

The aim of this study was to compare the rate of wear of acetabular polyethylene using conventional cross linked versus highly cross linked polyethylene.

From June 2001 to September 2003, 119 patients were followed prospectively for up to five years on an annual basis in a double blinded, randomised trial. The mean age of patients was 59 years (range 48 to 75 yrs). The radiographs have been analyzed using previously validated measurement software to assess linear, three dimensional and volumetric wear.

The five year results show significantly reduced wear rates for highly cross linked polyethylene compared to conventional polyethylene. There was no statistically significant difference between groups with respect to age, sex, operative side, surgeon, cup abduction angle, cup anteversion or size of cup.

The reduction in wear shown after five years with the highly cross linked polyethylene is highly encouraging and is consistent with in vitro wear simulator testing. This may reduce failure of total hip arthroplasties due to wear and osteolysis over the medium to long term.

Introduction and Aims: To define the economic and health costs of waiting for THJR surgery.

Method: A prospective cohort of 122 patients requiring primary total hip arthroplasty (HA) was recruited from four hospitals. 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.

Results: The mean waiting time was 5.2 months, and the mean cost of waiting for surgery was NZ$1376 per person per month, with medical, personal, and social costs contributing NZ$404, NZ$399, NZ$573, respectively. Waiting for more than six months was associated with an increased cost of NZ$730 per patient per month for a total cost of NZ$2177 per patient per month. Age was correlated with greater loss of income and higher medical costs. An incremental improvement over time in WOMAC scores post-operatively was identified. Older age, community services card use and a greater number of months waiting were negatively correlated with post-surgical improvement.

Conclusion: Longer waits for HA incur greater economic costs and impact on patient recovery. This shows that shorter waiting time for HA significantly reduces costs to individuals and society and improves health outcomes.

We have developed and tested the accuracy of a completely automated method for polyethylene (PE) wear measurement of digitised antero-posterior and lateral radiographs.

New computer algorithms have been developed to measure PE wear on digitised hip radiographs. The only user input required is the file name of the x-ray. Validation was performed by simulation of PE wear in an acrylic phantom. Radiographs were analysed with the new software and results were compared to know penetration of the femoral head.

Accuracy using 10 antero posterior and lateral phantom radiographs was within ±0.08mm (95% CI) of the real femoral head penetration. There was no inter or intra-observer error (identical results with all measurements). Perhaps most importantly, this system gave accurate results in 94% of 600 clinical radiographs of variable quality. Only 74% of this same group of radiographs were considered of sufficient quality to allow reliable manual measurement.

This new method of PE wear measurements eliminated inter and intra-observer error, allowing comparison of wear results between different institutions. Accuracy is improved, but still limited by resolution of the scanned image.

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.

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.

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 aim of the study was to assess the outcome of fractures of the fifth metacarpal neck and to develop an accurate method of assessing fracture angulation.

Forty-two patients who were available for review were assessed using a patient questionnaire, assessing range of movement, cosmesis, pain and strength. A trigonometric method of determining true fracture angulation from AP and oblique radiographs was developed. There were 36 males and 6 females with an average age of 23.4 years, with a minimum follow up of 12 months. Patients with fractures angulated more than 45 degrees in whom reduction was not performed had a significantly lower score for grip strength and function. 32 patients reported a mild cosmetic deformity. The method of reduction and the method and duration of immobilisation did not correlate with the final outcome. A phantom was constructed that confirmed the accuracy of the method of calculating true fracture angulation from the oblique radiographs.

Fractures of the fifth metacarpal neck if not reduced to a true angulation of less than 45 degrees produce an unsatisfactory outcome. A method of assessing true angulation has been developed.

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 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 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.

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.