Introduction

The health sector contributes the equivalent of 4.4% of global net emissions to the climate carbon footprint. It has been suggested that between 20% and 70% of health care waste originates from a hospital's operating room, the second greatest component of this are the textiles used, and up to 90% of waste is sent for costly and unneeded hazardous waste processing.

Waste from common orthopaedic operations was quantified, the carbon footprint calculated, and cost of disposal assessed. A discussion of the circular economy of textiles, from the author of the textile guidance to the Green Surgery Report follows.

Introduction

Flexor sheath infections require prompt diagnosis, and management with intravenous antibiotics and/or surgical washout followed by physiotherapy. Complication rates as high as 38% have been reported.

Fractures of the neck of femur are common in the older adult with significant morbidity and mortality rates. This patient cohort is associated with frailty and multiple complex medical and social needs requiring a multidisciplinary team to provide optimal care. The aim of this study was to assess the outcomes at 5 years following implementation of a collaborative service between the Orthopaedic and Geriatric departments of Southland Hospital in 2012.

Retrospective data was collected for patients aged 65 years and older who were admitted with a fragility hip fracture. Data was collated for 2011 (pre-implementation) and 2017 (post-implementation). Demographics and ASA scores were recorded. We assessed 30-day and 1-year mortality, surgical data, length of stay and complications.

There were 74 patient admissions in 2011 and 107 in 2017. Mean age at surgery was 84.2 years in 2011 and 82.6 years in 2017 (p>0.05). Between the 2011 and 2017 groups there has been a non-significant reduction in length of stay on the orthopaedic ward (9.8 days vs 7.5 days, p=0.138) but a significant reduction in length of stay on the rehabilitation ward (19.9 vs 9 days, p<0.001). There was a significant decrease in frequency of patients with a complication (71.6% vs 57%, p=0.045) and a marginal reduction in number of complications (p=0.057). Through logistic regression controlling for age, sex and ASA score, there was a reduction in the odds of having a complication by 12% between 2011 and 2017 (p<0.001). There was no difference in mortality between the groups.

The orthogeriatric model of care at Southland Hospital appears to have reduced both the frequency of complications and length of stay on the rehabilitation ward 5 years after its implementation. This is the first study in New Zealand demonstrating medium-term post-implementation follow-up of what is currently a nationally accepted standard model of care.

Studies have indicated that the shallow Ultra High Molecular Weight Polyethylene (UHMWPE) acetabular socket or the socket with no head center inset can significantly increase the risk of hip joint dislocation. A previous study suggested the rim loading model in UHMWPE socket and metal femoral head can generate an intrinsic dislocating force component pushing head out of socket. Recently there has been renewed interest in dual mobility articulations due to the excellent stability. The outer bearing couple of the dual mobility articulations are comprised of the UHMWPE femoral head and metal acetabular socket while inner bearing is the locked conventional metal-poly construct. The acetabular socket is also featured by an anatomically shaped head inset wall. The purpose of this study was to theoretically compare the intrinsic dislocating force between conventional metal head on UHMWPE socket articulations and the poly head on metal socket articulations used in the dual mobility cup under direct loading.

The 3-D finite element analysis (FEA) models were same as previous study but with different material combinations. Sixty FEA model assemblies were consisted of CoCr or UHMWPE femoral heads and their corresponding 10mm thick generic UHMWPE or CoCr acetabular sockets. There were five different head center insets of 0, 0.5, 1, 1.5 and 2mm for each of six bearing diameters of 22, 28, 32, 36, 40 and 44mm for either sockets. The joint load of 2,446N was applied through the femoral head center as the same fashion as previous study. The dislocating force generated by the joint loading force intrinsically pushed femoral head out of socket. FEA results were verified with two data points of physical testing of actual UHMWPE 28mm ID liners with 0 and 1.5mm head center insets.

The highest dislocating force was 1,269N per 2,446N of rim loading force for the 0mm head center inset in poly cup with 22mm CoCr femoral head or the case of easiest to dislocate. The lowest dislocating force was 17.7N per 2,446N force for the 2mm inset in CoCr socket with 44mm poly head which therefore was the least likely to dislocate. The average dislocating force decreased by 78% from metal head- poly cup couple to poly head - metal cup couple. The dislocating force decreased as the head center inset and head size increased in all material cases.

The study suggests that not only the head center inset and head size but also the bearing material combinations can affect the intrinsic dislocating force component. The dual mobility poly head and metal socket couple generates less intrinsic dislocating force in all comparable conditions for conventional metal head and poly socket couple. During the hip separation and vertical placement of the cup, all variables found in this study may play the important rules to maintain joint stability. The stiffened cup rim reduces the deformation and thus reduces the potential cup wedge effect to generate dislocating force. The result of this study should provide the guidance to improve acetabular cup design for better joint stability.

Purpose

The aim of the present study was to look at survivorship and patient satisfaction of a fixed bearing unicompartmental knee arthroplasty with an all-polyethylene tibial component.

Previous studies suggested that the shallow Ultra High Molecular Weight Polyethylene (UHMWPE) acetabular socket liner or the liner with no head centre inset can significantly increase the risk of hip joint dislocation. Independent to the traditional neck impingement models, the purpose of this study was to investigate an additional dislocation force pushing the femoral head out of UHMWPE acetabular liner bearing under direct hip joint loading and the factors including the head centre inset affecting the magnitude of this force. The 3 D Finite Element Analysis (FEA) models were constructed by (30) 10 mm thick UHMWPE liners with six inner bearing diameters ranging from 22 mm to 44 mm and five head centre insets in each bearing size from 0 mm to 2 mm. A load of 2 446 N was applied through the corresponding CoCr femoral head to the rim of the liner. The DF was recorded as a function of head centre inset and head diameter. The results were verified by the physical tests of two 28 mm head bearing liners with 0 and 1.5 mm head centre insets respectively.

The results showed that the highest DF was 1 269N in 0 mm head centre inset and 22 mm head. The lowest DF was 171 N in 2 mm head centre inset and 44 mm head. The DF decreased as the head centre inset and head size increased. When head centre inset increased from 0 mm to 1 mm, the DF was reduced more than 50%. Two experimental data points were consistent with the trend of DF curve found in the FEA.

We concluded that the new intrinsic dislocating force DF can be induced by the rim directed joint loading force alone and can reach as high as 51% of the femoral loading force. This can be the addition to the dislocating moment generated by the neck impingement. A head inset above 1mm can effectively reduce DF to less than 25% of the joint force. Furthermore, the larger head diameter generates less DF. The DF is likely caused by the wedge effect between the deformed polyethylene bearing and the femoral head. The inset allows the femoral head to be separated from the spherical bearing surface, thus reducing the wedge effect. Our observation of the stabilizing effect trend of the head centre inset was consistent with reported clinical data. However, the increased height of the capture wall also reduces the range of motion. It is therefore necessary to minimize the inset height with the maximum benefit of the stabilize effect. This study suggested the larger femoral head has the advantage of reducing the DF and the stabilizing effect is more effective when combining with the inset wall. The result of this study should provide the guidance to improve acetabular poly liner design for better joint stability.

Previous studies suggested the lack of capture wall of acetabular Ultra High Molecular Weight Polyethylene (UHMWPE) liner can significantly increase the risk of hip joint dislocation. To date, the dislocation studies have been focused on the femoral neck impingement models. The purpose of this study was to identify a new Dislocating Force (DF) generated by rim directed joint force alone and investigate the factors to affect the magnitudes of the DF. The 3 D Finite Element Analysis (FEA) models were constructed by (30) 10 mm thick UHMWPE liners with six inner bearing diameters ranging from 22 mm to 44 mm and five capture wall heights in each bearing size from 0 mm to 2 mm. A load of 2 446 N was applied through the corresponding CoCr femoral head to the rim of the liner. The DF was recorded as a function of capture wall height and head diameter. The results were verified by the physical tests of two 28 mm head bearing liners with 0 and 1.5 mm capture wall heights respectively.

The results showed that the highest DF was 1 269N in 0 mm capture wall and 22 mm head. The lowest DF was 171 N in 2 mm capture wall and 44 mm head. The DF decreased as the capture wall and head size increased. When capture wall increased from 0 mm to 1 mm, the DF was reduced more than 50%. Two experimental data points were consistent with the trend of DF curve found in the FEA.

We concluded that the new intrinsic dislocating force DF can be induced by the rim directed joint loading force alone and can reach as high as 51% of the femoral loading force. A capture wall height above 1mm can effectively reduce DF to less than 25% of the joint force. In addition, the larger head diameter also resulted in less DF generation.

Introduction and Aims: Cold therapy is known to reduce pain and swelling after surgical procedures on the knee. We hypothesised that if cold therapy is started earlier, then there would be a reduction in pain and swelling in patients undergoing arthroscopic anterior cruciate ligament [ACL] reconstruction.

Method: We prospectively randomised 40 patients undergoing arthroscopic ACL reconstruction with hamstring autograft, to receive either room temperature [19° C] or cold [4° C] arthroscopy irrigation fluid. Patients were then assessed over the following seven days, with regard to pain [measured on a visual analogue scale], and swelling [measured with limb girth at four points around the knee].

Results: Pain scores were consistently reduced in the cold fluid group compared to the room temperature group throughout the post-operative period, and this difference was significant [p< =0.05] from six hours until seven days post-operatively. At day seven, the swelling measured at 5cm below the joint and 5cm above the joint were significantly lower in the cold group compared with the room temperature group. Drainage from the intra-articular drain was significantly lower in the cold group.

Conclusion: The use of cold irrigation fluid is a simple and safe measure by which pain and swelling (at day 7) can be reduced in the early post-operative period for arthroscopic ACL reconstruction.

Current issues being debated in ACL reconstruction include injury prevention, graft choice, graft positioning, graft fixation, graft remodelling and rehabilitation. Tissue engineering, the alteration of biological mechanisms by application of novel proteins, enzymes and hormones, is rapidly changing the way we approach all aspects of surgery. Tissue engineering techniques in ACL/PCL reconstruction focus on new biosynthetic ACL material, fixation of soft tissue grafts to bony tunnels and graft remodelling

OP-1 is recombinant human Osteogenic Protein 1 (BMP-7). It is a member of the Transforming Growth Factor β (TGFβ) super family. OP-1 promotes the recruitment, attachment, proliferation and differentiation of pluripotential mesenchymal stem cells. It promotes both osteogenesis and chondrogenesis. The carrier is highly purified bovine bone type 1 collagen, which provides an osteoconductive matrix.

We have completed a study assessing the use of OP-1 as a means of enhancing early biological fixation of soft tissue grafts within bone tunnels in a sheep ACL model.

We have commenced a clinical trial using OP-1 in adult ACL reconstruction, believing that OP-1 will enhance early biological graft fixation, and hence, improve clinical results, speed up rehabilitation and prevent tunnel widening.

Other studies have shown the beneficial effects of BMP-2 on an extraarticular bone tendon fixation model, the use of TGF-B to enhance graft remodelling and the application of gene therapy to deliver BMP’s for enhanced graft fixation.

Several projects are underway looking at creating biosynthetic ACL grafts using tissue engineering techniques. As opposed to purely synthhetic grafts, bioACL grafts are made of a collagen scaffold, allowing for remodelling and revascularisation.

ACL reconstructive surgery is constantly evolving. Tissue engineering may provide us with a means of minimising morbidity, accelerating rehabilitation and improving the clinical outcome following this common surgery.

We report the use of the uncemented Kotz modular femur and tibia reconstruction system after 95 distal femoral resections performed from 1983 to 1989. The average follow-up was 51 months; 62 patients had at least 36 months' follow-up and 36 at least 60 months. Complications required reoperation in 55%. The postoperative infection rate was 5% for primary cases, 6% for revision cases, and 43% for revision of previously infected cases. The polyethylene bushes failed in 42% of cases at an average of 64 months postoperatively. Stem breakage occurred in 6% and was associated with the use of narrow stems and extensive quadriceps excision. The radiological results were excellent or good in most cases and were related to the initial screw fixation, but not to age, chemotherapy, length of resection or size of stem. The clinical results were excellent or good in 75%, failure usually being associated with a complication, especially infection.