This study aimed to examine the changing trends in the causes for early revision of total hip replacements (THR) in one country over fifteen years to assess whether changes in arthroplasty practices have changed revision patterns.

The cause for revision within one year was extracted from the New Zealand Joint Registry for the period of January 1999 to December 2013. The results were grouped into three periods of 5 years (Period 1=1999–2003, Period 2=2004–2008 and Period 3 = 2009–2013). The causes were compared across the three periods and were adjusted for age, gender and ASA grade.

The rate of early revisions (within one year) rose from 0.86% to 1.30% per year. There was significant rise in revision for deep infection (14% increased to 21% of all causes, p<0.001) and femoral fracture (5% increased to20%, p<0.001), whereas revision for dislocation decreased (55% decreased to 35%, p<0.001). Adjusting for age and gender femoral fracture and deep infection rates remained significant for both (p<0.05). Adjusting for age, gender as well as ASA only remained significant for infection (P<0.05).

The reduction in revision for dislocation followed the registry trend for the use of larger femoral heads and cross linked polyethylene. The rise in early periprosthetic femoral fracture rates was directly associated (p<0.001) with the increased use of uncemented femoral prostheses. The worrying increase in infection rate was unexplained on the basis of registry data alone. It was related to ASA grade but the overall ratios of ASA grades remained consistent over the 15 years.

The aim of the New Zealand National Shoulder Arthroplasty Register is to evaluate the provision of shoulder arthroplasty across the entire country by both recording accurate technical information and measuring the clinical outcomes of all shoulder replacements performed in New Zealand.

An initial form is completed at the time of surgery which includes details of the patient, surgical indications, the surgical procedure, the implant and the operating surgeon. Six months following surgery, all registered patients are asked to complete the Oxford Shoulder Score and comment on post-operative complications.

Data from 686 consecutive primary and 44 revision shoulder arthroplasties were prospectively collected from January 2000 until December 2003. 82 surgeons performed shoulder arthroplasty during the study period but only 9 performed on average more than 5 per year. Their results at 6 months were statistically superior to those provided by other surgeons. Amongst all diagnoses, osteoarthritis scored significantly better than the rest and for this condition total shoulder replacement scored higher than hemiarthroplasty. 15 different prostheses were used, many of them too infrequently. There was no difference in outcome amongst the 5 most commonly used prostheses. The number of complications reported by patients and the revision rate within the study period was low. No benefit was observed in the use of laminar flow theatre to prevent infection.

The combination of technical data about the joint implanted and the individual patient assessment has made the New Zealand Shoulder Arthroplasty Register unique in its own kind. Our findings are in general agreement with the current literature and supports the idea that shoulder arthroplasty is better provided by surgeons with a higher yearly case-load.

The purpose of this study was to investigate the surgical options for unicompartmental osteoarthritis (OA) in younger patients by comparing the survivorship and functional results of Total Knee Replacement (TKR) following osteotomy with the results for both primary TKR and revision of Unicompartmental Knee Replacement (UKR) to a TKR, and thereby recommend the most appropriate index procedure for this group of patients.

We reviewed the revision rate and functional outcome of all patients who had a total knee replacement (TKR) following an osteotomy or Unicompartmental Knee Replacement (UKR) on the New Zealand Joint Registry. We used this data to compare the results to primary TKR scores, including comparison of age-matched subgroups.

There were 711 patients who had undergone TKR as salvage for a failed osteotomy with a revision rate of 1.33 revisions per 100 component years and a mean Oxford knee score (OKS) of 36.9. 205 patients had failed UKR converted to TKR with a revision rate of 1.97 revisions per 100 component years and a mean OKS of 29.1. The revision scores of TKR for both failed osteotomy and failed UKR were significantly poorer than following primary TKR (p← 0.05). The mean OKS following revision of a UKR was significantly poorer than both primary TKR (p←0.001) and TKR for a failed osteotomy (p←0.001). There was no significant difference in mean OKS between primary TKR and TKR for a failed osteotomy, even amongst patients younger than 65 years (p=0.8).

This study has shown that if a surgeon is choosing between an osteotomy and a UKR in the younger patient than the better for any subsequent revision procedure will be achieved with an osteotomy. Revision of a failed osteotomy to a TKR has improved functional results compared to revision of a failed UKR. However, both yield poor survivorship rate compared to primary TKR.

This study reviewed the revision rate of fully cemented, hybrid and cementless primary total knee replacements (TKR) registered in the New Zealand Joint Registry from 1999 to May 2008 to determine whether there was any significant difference in the survival and reason for revision with these different types of fixation.

The percentage rate of revision was calculated per 100 person years (HPY) and compared to the reason for revision, type of fixation and the patient’s age.

Of the 28707 primary TKR registered, 522 underwent revision procedures requiring change of at least one component with a survival rate of 0.44 HPY (1.8%). The majority of revisions were for pain (153) followed by deep infection (133) followed by loosening of the tibial component (98). Overall the rate of tibial loosening was 0.07 HPY (0.3 %) in the cemented group vs 0.25 HPY (1%) in the cementless group (p < 0.001). There was no significant difference in the type of fixation used for the femoral component, but there was a significant difference in the different types of fixation when revised for pain, with the uncemented tibia performing the poorest. There was no significantly difference in the younger patient (< 55 years) with respect to tibial loosening (p=0.92).

Failure of the uncemented total knee replacement was due to pain and tibial loosening although the results in patients under 55 years were similar in all fixation groups. There was no difference in the fixation method of the femoral component.

We reviewed the rate of revision of unicompartmental knee replacements (UKR) from the New Zealand Joint Registry between 1999 and 2008. There were 4284 UKRs, of which 236 required revision, 205 to a total knee replacement (U2T) and 31 to a further unicompartmental knee replacement (U2U). We used these data to establish whether the survival and functional outcome for revised UKRs were comparable with those of primary total knee replacement (TKR). The rate of revision for the U2T cohort was four times higher than that for a primary TKR (1.97 vs 0.48; p < 0.05). The mean Oxford Knee Score was also significantly worse in the U2T group than that of the primary TKR group (30.02 vs 37.16; p < 0.01). The rate of revision for conversion of a failed UKR to a further UKR (U2U cohort) was 13 times higher than that for a primary TKR.

The poor outcome of a UKR converted to a primary TKR compared with a primary TKR should contra-indicate the use of a UKR as a more conservative procedure in the younger patient.

To ascertain whether there is any relationship between the Oxford 12 scores gained six months post surgery and early revision for primary hip and knee arthroplasty.

The six month post surgery Oxford 12 scores were retrieved from the National Joint Registry (NJR) for the seven year period ending 31^st December 2006. These were analysed in relation to revision of primary hip and knee procedures using three methods of statistical analysis; logistic regression, receiver operating characteristic (ROC) curve and direct plotting of groups of scores against the proportion of hips revised for that same group.

Logistic regression: For every one unit increase in the Oxford score there was an 11% increased risk of revision (hips) and 12% (knees) within the first two years of surgery, 5 and 6% respectively between two and four years and 3 and 4% risk respectively between four and six years (p> 0.001).

The ROC Curve Analysis: demonstrated that a patient with a score greater than 20 (hips) or 28.5 (knees) or 24 (uni knees) has eight times the risk of needing a revision within two years compared to a person with a score equal or less than the above numbers. Alternatively the ROC analysis predicted 73% of the revisions within three years for all three arthroplasty groups.

Plotting Scores Against Revisions: Plotting scores in groups of five demonstrated an incremental increase in the risk during the first two years. A person with a score greater than 40 has; for hips 24 times, knees 27 times and uni knees 69 times the risk of a revision within two years compared to a person with a score between 16 and 20.

Monitoring of the six month post surgical Oxford 12 score is another tool in the surgeon’s armamentarium for deciding which patients need closer monitoring following arthroplasty surgery.

A previous audit of New Zealand Joint Registry data showed that, overall, OXF UKA had over three times the seven–year revision rate (RR) compared with TKA. Where the RR was calculated for surgeons performing one or more OXF UKA per month, however, the RR was comparable to that for all–surgeon TKA (Hartnett et al, NZOA ASM, 2007).

To audit and compare revisions of OXF UKA and TKA performed by one surgeon, as recorded in the New Zealand National Joint Registry, and to highlight a complication of OKF UKA unreported in the literature.

The data from a personal series of 177 consecutive medial Oxford (Phase three) cemented UKAs entered in the Registry from January 2000 to December 2007 was analysed. The number and reasons for revision of the cohort was compared with a similar personal cohort of 229 consecutive cemented TKAs performed over the same period. Comparison was also made between this personal data with that for all surgeons recorded in the Registry.

OXF UKAs were performed at a mean rate of 1.8 procedures per month. The prime indication was antero-medial osteoarthritis: valgus stress x-rays performed routinely had to establish adequate thickness of lateral articular cartilage and ACL had to be competent before the UKA was preferred to TKA. Fifty six (31.6%) of the 177 operations were performed as part of bilateral procedures under the one anaesthetic.

Two OXF UKAs were revised to TKA. In neither was there failure of fixation or integrity of the prosthesis: one case was revised for unexplained pain where OXF UKA was for post–traumatic medial OA. The 2nd revision followed recurrent haemarthrosis and subsequent joint destruction: arteriography found no arterial injury. The RR for personal OXF UKA was therefore 1.1%, which compares with personal TKA RR of 2.2% (difference not significant p=0.42). The RR for all OXF UKAs in NZ was 5.6%, and that for TKA was 1.8%. The difference between personal and national RR for OXF UKA is significant (p=0.010), and that for TKA is not (p=0.63).

Since 2000, two other revisions of OXF UKA outside the studied cohort both followed recurrent haemarthrosis causing joint destruction. The results of OXF UKA reported here confirm that an early revision rate comparable to TKA is achievable when this surgery is performed relatively frequently by the surgeon. Recurrent haemarthrosis occurring later after early successful OXF UKA surgery is not recorded in the English literature. It has been the most frequent reason for revision (three of four revisions).

To identify frequency and patterns of Oxford Phase 3 Unicompartmental Knee Arthroplasty (UKA) failure in New Zealand through analysis of national primary and revision data. Compare the results of this data with that of total knee arthroplasty and other international joint registers.

Retrospective audit examining all Oxford Phase 3 UKAs recorded in the New Zealand National Joint Register from January 2000 to December 2007 were analysed and then statistic al analysis performed to identify patterns of failure and reasons for revision.

Two thousand six hundred and twenty Oxford UKAs were performed by 99 Orthopædic Surgeons. The average age was 66.1 years (range 35–94).

Osteoarthritis was the primary diagnosis. Mean time to revision 839 days (2.3 years). Revision rate was 5.6% (n=148). The most common reasons for revision were pain (n=61, 41%), aseptic loosening (n=53, 36%), and bearing dislocation (n=16, 11%). Deep infection rate was 0.26% (7/2620) compared with 1.76% of total knee arthroplasties (564/32029). Six surgeons (high use & #8805;10 UKAs/year) performed 699 (26.7%) operations, revision rate 2.6%. Fifty-five surgeons (low use & #8804; two UKA/year) performed 283 (10.8%) operations, revision rate 10.6%. There was a statistically significant difference seen with an inverse relationship between surgeon experience and revision. The revision rate for the Oxford is three, two times greater than TKA.

UKA is now decreasing in New Zealand whilst Total Knee Arthroplasty (TKA) continues to increase. The number of is now decreasing in New Zealand whilst Total Knee Arthroplasty (TKA) continues to increase. The number of surgeons using Oxford UKA has increased by 19% but the number of Oxfords being done has fallen by 13%. High use surgeons’ revision rate is now higher than TKA. An inverse relationship between failure and surgeon experience exists which confirms Swedish Knee Arthroplasty register reports. The deep infection rate is less than TKA. Revisions were performed early for unexplained pain in the absence of obvious mechanical failure. This is against generally held wisdom for TKA and may reflect the perception that UKA is easily revised to TKA.

Recent analysis of the Australian Joint Replacement Registry revealed the rate of revision of primary total hip arthroplasty was greater with cement-less fixation than with cemented fixation. The seven-year results of the New Zealand Joint Registry have also shown an increased revision rate with cement-less hip arthroplasty. The purpose of this study was to review the revision rate of cemented and cement-less total hip arthroplasty from those joint replacements registered with the New Zealand Joint Registry and to determine the cause for revision.

All 42 1000 primary total hip arthroplasties recorded in the New Zealand National Joint Registry since its establishment in 1999, until December 2006, were included in the study. The rate of revision of cemented and cement-less femoral and acetabular components was calculated for the study period, and for the first 90 days after the operation. The reasons for revision were evaluated and compared for different methods of fixation. Survival curves were constructed for each combination of femoral and acetabular component fixation.

Two hundred and eighty three cement-less (2.46%), 294 cemented (1.91%), and 321 cemented femoral with cement-less acetabular fixation (2.19%) primary total hip arthroplasties have been revised. The difference in revision rate between each group was statistically significant. There were only 573 primary total hip arthroplasties performed with cement-less femoral and cemented acetabular component, with 11 revised. The rate of revision was highest in the cement-less group (0.74% revised per year), and lowest in the cemented group (0.47%).

The predominant reason for revision in all three major groups was dislocation. Revision for loosening of the acetabulum was more common with cemented fixation. Revision for fractured femur was more common with cement-less fixation, and revision for deep infection was most common in the cemented group. These differences were all shown to be statistically significant. Revision for loosening of the femoral component and pain was more common in the cement-less group, but was not shown to be statistically significant.

In the first 90 days, there were a large number of revisions in the cement-less group (0.77%), compared to the cemented group (0.32%), and cemented femur with cement-less acetabulum group (0.57%). Dislocation was again the most common reason for revision. Revision for fractured femur was high in the cement-less group (0.19%) in the first 90 days. Excluding these early revisions, the number of revisions in the cemented and cement-less groups maintained a similar rate for the remainder of the study period.

This study confirmed that the revision rate for uncemented THA was higher than for cemented THA. The major difference was the early revision rate within 90 days. Addressing these problems would improve the overall early outcome.

Articular cartilage has a limited regenerative capacity. Tissue engineering strategies adopting seeding and differentiation of individual chondrocytes on porous 3D scaffolds of clinically relevant size remains a considerable challenge. A well documented method to produce small samples of differentiated cartilage tissue in vitro is via micro-mass (pellet) culture, whereby, high concentrations of chondrocytes coalesce to form. a spherical tissue pellet. However, pellet culture techniques are not applied clinically as it is only possible to produce small amounts of tissue (1–2mm). The aims of this study were to develop a method for mass-production of pellets, and investigate whether an alternative “pellet seeding” approach using smart 3D scaffold design would allow large numbers of spherical pellets to be fixed in place.

Chondrocytes were isolated from bovine articular cartilage via enzymatic digestion. Freshly isolated and expanded (passage 2) chondrocytes were placed in 96-well plates with round- or v-shaped wells at a range of densities from 0.1, 0.25 and 0.5 million cells per pellet, and centrifuged at 500g for 2 min. In order to assess pellet forming conditions, cells were treated with or without 300 mg/mL fibronectin (FN, Sigma) to improve cell-cell adhesion. Wells were also coated with or without silicone (Sigmacote) to prevent cell adhesion to wells. Pellets were cultured in vitro for up to 14 days and were assessed at various timepoints for size, shape, cell number (DNA assay) and cell differentiation capacity (histology). A robotic Bioplotter device was used to produce porous, biodegradable scaffolds by plotting −250μm polymer (PEGT/PBT) fibres in a layer-by-layer process. Scaffolds with specific 3D pore architecture were produced to allow spherical pellets to be press-fit in each pore thereby fixing them in place throughout the scaffold.

Primary and expanded chondrocytes plated at a density of 0.25 million cell/pellet in v-shaped 96-well plates without both FN and silicone treatment produced pellets with consistently better spherical shape and total cell number (as determined via DNA). Under these conditions, cell (re)differentiation and cartilage extracellular matrix formation was observed via positive staining for safranin-O. Mass production of pellets was achieved by culturing multiple 96-well plates in parallel. FN treatment promoted cell-cell adhesion, but also cell adhesion to well plates, irrespective of silicone treatment, resulting in irregular shaped pellets, as did the use of round-bottom shaped wells.

Smart scaffold design and layer-by-layer fabrication process allowed direct control over the fibre spacing and pore size (1.0–1.25mm). Multiple layers of spherical pellets (1.25–1.5mm) were press-fit in place, thereby limiting the need for direct cell adhesion to the scaffold. Continued culture of constructs containing pellets resulted in consistent tissue formation throughout the scaffold.

In this study, we describe an alternative approach to the design and seeding of scaffolds for cartilage tissue engineering. Current limitations involved with adherence and de-differentiation of single cell populations were avoided by taking advantage of smart 3D scaffold design and pellet-seeding and culture techniques. Further optimisation and automation of the process is necessary, however, such strategies could be beneficial for future scaffold-based cell therapies for repairing articular cartilage defects.

The purpose of this study was to identify causes of failure and rates of revision of the Oxford prosthesis (OXF) in New Zealand, by reviewing and comparing the uni-compartmental (UKA) and total knee arthroplasty (TKA) data from January 2000 to December 2005, as recorded in the New Zealand National Joint Registry.

Eighty one orthopaedic surgeons performed 2006 Oxford UKAs (64% of all UKAs). The revision rate was 4.7%. This compared with a revision rate of 4.8% for all UKAs combined, and 1.6% for TKA. UKA (3122) made up 13% of all knee arthroplasties (24 260). The most common reasons for revision of the OXF were aseptic loosening (45%), unexplained pain (33%) and bearing dislocation (12%). Unexplained pain as the only reason for revision (33%) was significantly different (p = 0.001) from the TKA rate (23%).

Deep infection as a cause for revision was 0.20% for the OXF compared with 0.48% for TKA (p=0.07). The patient- generated Oxford scores at six months after operation were rated excellent or very good (Field et al, 2004) in 68% of OXF compared with 62% TKA patients (p = 0.001).

Five higher-use OXF surgeons (12 or more/year) performed 25.1% of the operations with a revision rate of 0.99%. Ten high- use surgeons (eight to 11/year) performed 28.1 % of operations with a revision rate 4.6%. Thirty medium-use surgeons (two to seven/year) performed 39.0% of the operations with a revision rate of 6.4%. Thirty-six low-use surgeons (one or less/ year) performed 7.8% of the operations with a revision rate of 8.3%. The difference in revision rate between the higher-use surgeons (one operation/month) and all the other three lower use groups was significant (e.g. p=0.0006 higher/low)

The early revision rate for the OXF was 2.9 times greater than that for TKA. However, higher-use surgeons (i.e. those performing one/month or more) had a revision rate comparable to TKA. Deep infection was lower and six month function scores were higher for OXF compared with TKA. Unexplained pain as the only reason for revision was significantly higher for OXF compared with TKA.

We have examined the outcome of 400 consecutive patients who underwent total knee replacement with the Low Contact Stress mobile-bearing system between 1993 and 1994 and were followed up for a minimum of ten years. All operations were performed by surgeons in Christchurch, New Zealand, who used no other knee prosthesis during the study time.

At ten years after operation 238 patients (244 knees) remained for independent clinical and radiological assessment. There was a significant improvement (p < 0.001) in the postoperative knee scores at one, three, seven and ten years, although a slight deterioration in the score occurred between seven and ten years which did not reach statistical significance. The survival for polyethylene wear or loosening was 97% (95% CI 96 to 98) and survival using reoperation for any cause was 92% (95% CI 90 to 94) at 12 years. Polyethylene wear was more common in the meniscal-bearing component, with five knees requiring revision and a further eight demonstrating early wear. Osteolysis was not seen in the rotating platform component, but was present in three of the meniscal-bearing knees.

There was no association between the radiological alignment at one year and those knees that subsequently required revision. However, there was an association between the overall limb alignment and the Western Ontario McMasters University score (p < 0.001).

The Low Contact Stress mobile-bearing total knee replacement has proved to be a reliable implant at ten years when used in primary knee replacement irrespective of the deformity and diagnosis.

The aim of the New Zealand Elbow Arthroplasty Register is to evaluate the provision of elbow arthroplasty across the entire country by both recording accurate technical information and measuring the clinical outcomes of all elbow replacements performed in New Zealand. An initial form is completed at the time of surgery which includes details of the patient, surgical indications, the surgical procedure, the implant and the operating surgeon. Six months following surgery, all registered patients are asked to complete a questionnaire to measure the pain and function of the replaced elbow and to comment on any post operative complications. Data from 99 consecutive primary and 16 revision elbow arthroplasties was prospectively collected from January 2000 till December 2003. Rheumatoid arthritis was the commonest indication (63 cases) and the outcome was significantly better than for trauma and osteoarthritis. The Coonrad-Morrey was the most commonly used prosthesis (86 cases) followed by the Kudo (eight cases) and the Acclaim (five cases). 21 surgeons performed elbow arthroplasty during the study period but only five performed on average more than one case per year. Their results at six months were statistically superior to those provided by other surgeons. The number of complications reported by patients and the revision rate within the study period was low. An infection was seen in only two patients. The New Zealand Elbow Arthroplasty Register has become a robust method of assessment of the provision of elbow arthroplasty within the country. Our findings support the idea that elbow arthroplasty should not be performed by general orthopaedic surgeons on an occasional basis.

The aim was to study the outcome of the vein wrap technique in the treatment of post carpal tunnel causalgia (CRPS type II).

Five patients with a diagnosis of post carpal tunnel release causalgia were treated with the vein wrap technique. This involves performing an extended carpal tunnel release gently freeing all nerve adhesions and then wrapping the endothelial surface of a longitudinally split segment of the cephalic vein around the median nerve from proximal to the carpal tunnel to the commencement of the distal divisions. The wrap is secured with 6.0 Novafil sutures. Post surgery the wrist and hand are supported in a volar slab and bandage for two weeks followed by patient managed mobilising exercises. There were three females and two males with follow-up ranging from six months to three years. Time from onset of causalgia to surgery ranged from 6 months to 13 years. In three patients there was immediate and profound relief of causalgic symptoms; in one, symptoms completely resolved over six weeks and in one, in which the nerve had been severely crushed prior to initial surgery, the causalgic symptoms markedly improved but the post injury numbness has persisted. In none has there been recurrence or deterioration.

Post carpal tunnel release causalgia is a devastating and disabling complication. It is often resistant to a range of treatment modalities but the vein wrap is a simple procedure which in the author’s experience can be dramatically effective even in patients with very long standing causalgia.

To identify frequency and patterns of Oxford Phase 3 UKA failure in New Zealand through analysis of national primary and revision data.

Retrospective audit examining all revision Oxford Phase 3 UKAs recorded in the New Zealand National Joint Register from January 2000 to October 2003 were analysed along with surgeons’ clinical notes and patient x-rays.

Seventy-three Orthopædic Surgeons performed 1216 Oxford UKAs. The average age was 66.4 years (range 35–94). Osteoarthritis was the primary diagnosis for 1163 (96%) patients. Mean time to revision was 437 days (14.4 months). The early revision rate was 2.2% (n=27). The most common reasons for revision were aseptic loosening (n=7, 26%), bearing dislocation (n=5, 19%) and pain (n=4, 15%). The deep infection rate was 0.16% (2/1216). Eighteen surgeons (high use > 8 UKAs/year) performed 787 (64%) operations, with a revision rate of 1.5%. Twenty-two surgeons (low use ≤ 1 UKA/year) performed 38 (3%) operations, with a revision rate of 8%. This was statistically significant, p= 0.03 (odds ratio 5.7).

The early revision rate for the Oxford UKA is 1.4 times greater than TKA. High use surgeons revision rate is lower than TKA. An inverse relationship between failure and surgeon experience exists. This confirms Swedish Knee Arthroplasty Register findings.

The aim was to compare the medium term results of metacarpophalangeal joint (MCPJ) arthroplasty using three different types of silicone hinged implants.

All rheumatoid arthritis patients undergoing four finger MCPJ arthroplasty at Burwood Hospital have had standardised pre and post operative assessments for up to four years consisting of: measurement of MCPJ active arc of motion (AOM); finger ulnar drift (UD) and the Baltimore upper extremity function test (UEFT). All surgery was undertaken or directly supervised by one surgeon using a standardised technique followed by a dynamic and static splintage programme supervised by the same hand therapists.

Implants – Swanson; 25 hands, 100 joints, 1989 to 1995 – Avanta; 27 hands, 108 joints, 1995 to 2000 – Neuflex; 11 hands, 44 joints, 1999 to 2003

Swanson – at two years the AOM changed from 46 – 80° to 15 – 51°; UD reduced from 33 to 4°and 66% had improved from partial and poor to functional UE categories.

Avanta – the AOM changed from 51 – 79 to 15– 60; UD from 31 to 7° and 67% had improved to functional.

Neuflex – the AOM changed from 42 – 68 to 17 – 63°; UD from 32 to 11 and 45% had improved to functional classification.

From two to four years the UEFT for the Swanson and Avanta had significantly deteriorated.

The medium term outcomes for the three implants were very similar. Neuflex use was discontinued in 2003 because of early recurrence of ulnar drift. The significant deterioration of hand function from two to four years is likely to be the effect of progressive rheumatoid disease as the AOM and UD remained unchanged.

The purpose of this study was to evaluate the results of simultaneous bilateral total hip and total knee arthroplasty performed in New Zealand during the first five years of the New Zealand National Joint Register and to determine whether this was an acceptable practice.

All total knee and total hip arthroplasties collected on the National Joint Register between 1999 and 2003 were divided into three groups – unilateral joint arthroplasty, staged bilateral joint arthroplasty and simultaneous joint arthroplasty. The Oxford 12 questionnaire results at six months were assessed as well as the patients self reported complications. All deaths that occurred within 6 months of the surgery were also recorded.

Analysis between the three groups was then performed using ANOVA tables comparing age, the Oxford scores and complications.

There was generally a significant difference (p< .001) in age between unilateral hip and knee replacement and staged or simultaneous bilateral replacement, with patients undergoing bilateral simultaneous replacement being younger.

There was a significant difference (p< .001) in the Oxford 12 scores between unilateral hip and knee replacement and both staged and simultaneous bilateral hip and knee replacement, with the bilateral simultaneous replacements scoring the best.

The death rate within the first 6 months was low in all groups with only 1 patient dying within 3 months of the surgery from an unrelated cause. The complication rate was low in all groups, in particular the DVT and pulmonary embolus rate, as reported by the patients, was not increased in either the sequential staged group or the simultaneous bilateral group.

The New Zealand National Joint Register has proven to be a valuable tool in gaining early information regarding the outcome following bilateral and staged lower limb total joint arthroplasty. The results clearly show that in the appropriate clinical situation performing simultaneous bilateral total knee or total hip arthroplasty is a safe and effective procedure.

Aim: To describe accurately the contributions of glenohumeral (GH) and scapulothoracic (ST) joints in shoulder movements in normal male adult subjects, aged 20–30 years.

Methods: We recorded data with a Polhemus magnetic tracking device (Kaiser Aerospace and Electronics Co., Vermont). Receivers were taped on landmarks, over the sternum, scapula and humerus. The movements that were studied were elevation in the sagittal plane, abduction in the scapular plane and lowering the arm from these positions. We collected data from 26 male subjects (52 shoulders), aged 20–30 years, with no history of shoulder problems. Repeatability data were obtained in 16 subjects.

The data can be expressed in a number of ways, including plotting the ratio of GH/ST movement versus overall shoulder movement. Polynomial equations to fit these curves describe movement patterns. We have developed software to calculate cumulative averaging of data.

Results: Both GH and ST movements contribute to shoulder movement throughout the ranges studied. Although the shapes of the movement curves were fairly consistent, there were some non-conforming curves and variations. As the arm is abducted the mean ratio of GH/ST movement increases to approximately 3/1. Adduction produces curves that nearly mirror image the abduction curves. Flexion and extension curves tend to be flatter with a mean GH/ST ratio of 2–3/1, throughout the range. The reproducibility data shows satisfactory fits to initial curves.

Conclusions: We have developed a method to describe shoulder movement that provides new information regarding normal shoulder movements. This method can be applied to study patients with shoulder disorders.

Aim: To measure the percentage increase in length of the donor graft during rehabilitation from 0 degrees to 120 degrees of elbow flexion and to compare this with the end range strength.

Method: During the troids procedure four metal skin-clips were inserted at the proximal and distal margins of the proximal and distal tibialis posterior tendon weaves creating three intervals for measurement. Lateral x-rays of the humerus with the tube distance at 100cms were taken after five weeks of plaster immobilisation before elbow flexion commenced at a maximum rate of 15 degrees per week. X-rays were repeated when 60 degrees and 120 degrees of flexion obtained and when possible six months post surgery. Elbow torque was measured by the Troidometer throughout the range of motion at similar time intervals. Interval measurement was by a Vidar VRX 12 digital scanner. The Paired T test was used for statistical analysis.

Results: Sixteen arms (nine patients) were entered into the study but complete rehabilitation data were available from only 12 arms and late data from only four. There was a 12.3% average increase between 0 degrees and 60 degrees (range six to 20.6 degrees) and a further 3% increase from 60 degrees to 120 degrees (range −6 degrees to 21 degrees). The most stretch occurred in the distal segment and in bilateral arms the percentage of stretch was similar for each arm. There was no correlation between the percentage of stretch and end range torque or lag.

Conclusions: The Troids transfer restores elbow extension for tetraplegics but an extensor lag often develops which is thought to be from stretching of the donor tendon graft. This study confirmed that tendon stretch occurs but there was wide variation among individuals although similar for each arm in bilateral procedures. An average of 75% of stretch occurred during the 0 degrees to 60 degrees mobilisation. We concluded that tendon stretch is inevitable but is not a major contributor to end range weakness or lag.

Introduction: The patterns of forearm and hand paralysis in traumatic tetraplegia are recognised and classified by an international classification system. Although weakness and wasting are common around the shoulder in tetraplegia, it is harder to discern individual muscle function.

Aim: To determine the activity of shoulder girdle muscles in patients with traumatic tetraplegia and to relate these results to the subjects’ international forearm classifications.

Methods: Twenty-five male tetraplegic subjects (50 upper limbs) were examined. Forearm muscle strengths were recorded according to the international classification system. The strengths of nine shoulder movements were recorded according to the Medical Research Council (MRC) grading system. The presence of wasting and the electromyographic (EMG) activity of nine shoulder muscle regions were noted. Using surface electromyography we noted whether voluntary EMG patterns were present or absent and whether lower motor denervation signs were present or absent.

Results: Absence of voluntary EMG activity was only seen in latissimus dorsi, and only in patients with very high-level lesions (either no MRC grade IV forearm muscles, or brachioradialis only, i.e. international forearm grade I or less). Lower motor neuron signs were observed in latissimus dorsi in most patients without ipsilateral MRC grade IV finger extension (international forearm grade VI or less). Lower motor neuron signs were observed in infraspinatus in most patients without MRC grade IV forearm pronation (international forearm grade IV or less).

Conclusions: Only patients with very high level lesions showed paralysis of any shoulder girdle muscles and, then, only latissimus dorsi. In most cases of traumatic tetraplegia shoulder girdle muscles have the capacity to be strengthened by use and rehabilitation.