To determine the risk of total knee replacement (TKR) for primary osteoarthritis (OA) associated with overweight/obesity in the Australian population.

This population-based study analyzed 191,723 cases of TKR collected by the Australian Orthopaedic Association National Joint Registry and population data from the Australian Bureau of Statistics. The time-trend change in incidence of TKR relating to BMI was assessed between 2015-2018. The influence of obesity on the incidence of TKR in different age and gender groups was determined. The population attributable fraction (PAF) was then calculated to estimate the effect of obesity reduction on TKR incidence.

The greatest increase in incidence of TKR was seen in patients from obese class III. The incidence rate ratio for having a TKR for obesity class III was 28.683 at those aged 18-54 years but was 2.029 at those aged >75 years. Females in obesity class III were 1.7 times more likely to undergo TKR compared to similarly classified males. The PAFs of TKR associated with overweight or obesity was 35%, estimating 12,156 cases of TKR attributable to obesity in 2018. The proportion of TKRs could be reduced by 20% if overweight and obese population move down one category.

Obesity has resulted in a significant increase in the incidence of TKR in the youngest population in Australia. The impact of obesity is greatest in the young and the female population. Effective strategies to reduce the national obese population could potentially reduce 35% of the TKR, with over 10,000 cases being avoided.

Proximal femoral focal deficiency is a congenital disorder of malformation of the proximal femur and/or the acetabulum. Patients present with limb length discrepancy and clinical features along a spectrum of severity. As these patients progress through to skeletal maturity and on to adulthood, altered biomechanical demands lead to progression of arthropathy in any joint within the lower limb. Abnormal anatomy presents a challenge to surgeons and conventional approaches and implants may not necessarily be applicable.

We present a case of a 62-year-old lady with unilateral proximal femoral focal deficiency (suspected Aitken Class A) who ambulated with an equinus prosthesis for her entire life. She presented with ipsilateral knee pain and instability due to knee arthritis but could not tolerate a total knee arthroplasty due to poor quadriceps control.

A custom osteointegration prosthesis was inserted with a view to converting to the proximal segment to a total hip replacement if required. The patient went on to develop ipsilateral symptomatic hip arthritis but altered acetabular anatomy required a custom tri-flange component (Ossis, Christchurch, New Zealand) and a custom proximal femoral component to link with the existing osseointegration component (Osseointegration Group of Australia, Sydney, Australia) were designed and implanted.

The 18 month follow up of the custom hip components showed that the patient had Oxford hip scores that were markedly improved from pre-operatively. Knee joint heights were successfully restored to equal when the patient's prosthesis was attached. The patient describes feeling like “a normal person”, walks unaided for short distances and can ambulate longer distances with crutches.

Advances in design and manufacture of implants have empowered surgeons to offer life improving treatments to patients with challenging anatomy. Using a custom acetabular tri-flange and osseointegration components is one possible solution to address symptomatic ipsilateral hip and knee arthropathy in the context of PFFD in adulthood.

Rates of prosthetic joint infection in megaprostheses are high. The application of silver ion coating to implants serves as a deterrent to infection and biofilm formation.

A retrospective review was performed of all silver-coated MUTARS endoprosthetic reconstructions (SC-EPR) by a single Orthopaedic Oncology Surgeon. We examined the rate of component revision due to infection and the rate of infection successfully treated with antibiotic therapy. We reviewed overall revision rates, sub-categorised into the Henderson groupings for endoprosthesis modes of failure (Type 1 soft tissue failure, Type 2 aseptic loosening, Type 3 Structural failure, Type 4 Infection, Type 5 tumour progression).

283 silver-coated MUTARS endoprosthetic reconstructions were performed for 229 patients from October 2012 to July 2022. The average age at time of surgery was 58.9 years and 53% of our cohort were males. 154 (71.3%) patients underwent SC-EPR for oncological reconstruction and 32 (14.8%) for reconstruction for bone loss following prosthetic joint infection(s). Proximal femur SC-EPR (82) and distal femur (90) were the most common procedures. This cohort had an overall revision rate of 21.2% (60/283 cases). Component revisions were most commonly due to Type 4 infection (19 cases), Type 2 aseptic loosening/culture negative disease (15 cases), and Type 1 dislocation/soft tissue (12 cases).

Component revision rate for infection was 6.7% (19 cases). 15 underwent exchange of implants and 4 underwent transfemoral amputation due to recalcitrant infection and failure of soft tissue coverage. This equates to a limb salvage rate of 98.3%. The most common causative organisms remain staphylococcus species (47%) and polymicrobial infections (40%).

We expand on the existing literature advocating for the use of silver-coated endoprosthetic reconstructions. We provide insights from the vast experience of a single surgeon when addressing patients with oncological and bone loss-related complex reconstruction problems.

The Australia and New Zealand Sarcoma Association established the Sarcoma Guidelines Working Party to develop national guidelines for the management of Sarcoma. We asked whether surgery at a specialised centre improves outcomes. A systematic review was performed of all available evidence pertaining to paediatric or adult patients treated for bone or soft tissue sarcoma at a specialised centre compared with non-specialised centres. Outcomes assessed included local control, limb salvage rate, 30-day and 90-day surgical mortality, and overall survival.

Definitive surgical management at a specialised sarcoma centre improves local control as defined by margin negative surgery, local or locoregional recurrence, and local recurrence free survival. Limb conservation rates are higher at specialised centres, due in part to the depth of surgical experience and immediate availability of multidisciplinary and multimodal therapy. A statistically significant correlation did not exist for 30-day and 90-day mortality between specialised centres and non-specialised centres. The literature is consistent with improved survival when definitive surgical treatment is performed at a specialised sarcoma centre.

Evidence-based recommendation: Patients with suspected sarcoma to be referred to a specialised sarcoma centre for surgical management to reduce the risk of local recurrence, surgical complication, and to improve limb conservation and survival.

Practice point: Patients with suspected sarcoma should be referred to a specialised sarcoma centre early for management including planned biopsy.

Complex acetabular reconstruction for oncology and bone loss are challenging for surgeons due to their often hostile biological and mechanical environments. Titrating concentrations of silver ions on implants and alternative modes of delivery allow surgeons to exploit anti-infective properties without compromising bone on growth and thus providing a long-term stable fixation. We present a case series of 12 custom acetabular tri-flange and custom hemipelvis reconstructions (Ossis, Christchurch, New Zealand), with an ultrathin plasma coating of silver particles embedded between layers of siloxane (BioGate HyProtect™, Nuremberg, Germany).

At the time of reporting no implant has been revised and no patient has required a hospital admission or debridement for a deep surgical site infection. Routine follow up x-rays were reviewed and found 2 cases with loosening, both at their respective anterior fixation. Radiographs of both cases show remodelling at the ilium indicative of stable fixation posteriorly. Both patients remain asymptomatic. 3 patients were readmitted for dislocations, 1 of whom had 5 dislocations within 3 weeks post-operatively and was immobilised in an abduction brace to address a lack of muscle tone and has not had a revision of their components.

Utilising navigation with meticulous implant design and construction; augmented with an ultrathin plasma coating of silver particles embedded between layers of siloxane with controlled and long-term generation of silver ion diffusion has led to outstanding outcomes in this series of 12 custom acetabular and hemipelvis reconstructions. No patients were revised for infection and no patients show signs of failure of bone on growth and incorporation. Hip instability remains a problem in these challenging mechanical environments and we continue to reassess our approach to this multifaceted problem.

In a society whereby the incidence of obesity is increasing and medico-legal implications of treatment failure are more frequently ending with the consulting doctor, clarity is required as to any restrictions placed on common orthopaedic implants by manufacturing companies. The aim of this study was to identify any restrictions placed on the commonly used femoral stem implants in total hip replacement (THR) surgery, by the manufacturers, based on patient weight. The United Kingdom (UK) National Joint Registry (NJR) was used to identify the five most commonly used cemented and uncemented femoral stem implants during 2012. The manufacturing companies responsible for these implants were asked to provide details of any weight restrictions placed on these implants. The Corail size 6 stem is the only implant to have a weight restriction (60Kg). All other stems, both cemented and uncemented, were free of any restrictions. Fatigue fracture of the femoral stem has been well documented in the literature, particularly involving the high nitrogen stainless steel cemented femoral stems and to a lesser extent the cemented cobalt chrome and uncemented femoral stems. In all cases excessive patient weight leading to increased cantilever bending of the femoral stem was thought to be a major factor contributing to the failure mechanism. From the current literature there is clearly an association between excessive patient weight and fatigue failure of the femoral stem. We suggest avoiding, where possible, the insertion of small stems (particularly cemented stems) and large offset stems (particularly those with a modular neck) in overweight patients.

Richard Carey Smith is an orthopaedic oncology surgeon with fellowship training in the UK, USA, Australia and Canada, and has worked in Zambia, Zimbabwe and Papa New Guinea. David Wood is head of the University Department of Orthopaedics in Perth, Western Australia. He did his masters in Africa, and first experienced Papa New Guinea on his medical elective, starting a lifelong commitment to medical aid work there.

Surgery for degenerative lumbar spondylolisthesis may entail both decompression and fusion. The knee-chest position facilitates the decompression, but fixation in this position risks fusion in kyphosis. This can be avoided by intra-operative re-positioning to the prone position. The aim of this study was to quantify the restoration of lordosis achieved by intra-operative repositioning and to assess the clinical and radiological outcome.

A total of forty consecutive patients with degenerative lumbar spondylolisthesis and stenosis were treated by posterior decompression and interbody fusion with pedicle screw fixation. The screw insertion, decompression and interbody grafting were performed with the patient in the knee-chest position. The patient was then re-positioned to the fully prone position for fusion. Sagittal plane angles were measured pre-, intra- and post-operatively. Clinical assessment was performed using SF-36 scores and visual analogue scores for back and leg pain.

The sagittal plane angle increased from median 16.0 degrees pre-operatively to 23.1 degrees post-operatively (p<0.01) and this was maintained at the last follow-up (mean 21 months). The SF-36 scores improved for 7 out of 8 domains and the physical score improved from 29% to 40% (p<0.05). The mean pain scores improved significantly from 7.5 to 3.8 for back pain and from 7.6 to 3.7 for leg pain (p<0.001).

Lumbar spondylolisthesis was found to be associated with a reduction of normal lumbar lordosis and the knee-chest position exacerbates this loss of lordosis. Intra-operative repositioning restored lordosis to greater than the pre-operative angle and was associated with a good clinical outcome.

Introduction: Chondral injuries of the knee are commonly seen at arthroscopy, yet there is no consensus on the most appropriate treatment method. However, untreated cartilage injury predisposes to osteoarthritis contributing to pain and disability. For cell-based cartilage repair strategies, an ex vivo expansion phase is required to obtain sufficient cells for therapeutic intervention. Although recent reports demonstrated the central role of oxygen in the function and differentiation of chondrocytes, little is known of the effect of physiological low oxygen concentrations during the expansion of the cells and whether this alters their chondrogenic capacity.

Methods: Articular mouse chondrocytes were prepared from the distal femoral condyles of adult mice and chondrocytes were liberated by collagenase type II treatment. Cells were cultured in RPMI 1640 media in monolayer under normoxic or hypoxic conditions (5% O2). Chondrogenic potential was subsequently assessed by plating the cells under micromass conditions and glycosaminoglycan deposition was determined by alcian blue staining. Having determined that oxygen tension infiuences murine chondrocyte expansion and differentiation, similar studies were conducted using adult human chondrocytes taken from knee arthroplasty off-cuts, and Aggrecan (ACAN) gene expression was analyzed using real-time quantitative PCR.

Results: Cellular morphology of cells from mouse articular cartilage was improved in hypoxic culture, with a markedly more fibroblastic appearance seen after greater than 2 passages in normoxic conditions. Micromass cultures maintained in hypoxic conditions demonstrated stronger staining with alcian blue, indicating stronger expression of cartilage-associated glycosaminoglycans. Expansions of human chondrocytes under hypoxic conditions led to an ~ 2-fold increase in the expression of ACAN in comparison to cells in normoxic conditions. Differentiation of passage 2 chondrocytes under hypoxic conditions also improved the expression of ACAN when compared to culturing under normoxia. Ten day hypoxic cultures exhibited an ~ 5-fold increase in ACAN expression in comparison to normoxic cultures. Interestingly, ACAN expression normoxic-cultured cells could be increased by > 4-fold by transfer to hypoxic conditions.

Conclusions: In vivo, the chondrocytes are adapted to an avascular hypoxic environment. Accordingly, applying 5% O2 in the expansion phase in the course of cell-based cartilage repair strategies may more closely mimic the normal chondrocyte microenvironment and may result in a repair tissue with higher quality by increasing the content of glycosaminoglycans.

We aim to assess the clinical and radiological outcome following cartilage repair in the knee using the TruFit plug (Smith & Nephew). Eleven active sporting patients underwent cartilage repair using TruFit plugs between February 2006 and August 2007. Postoperatively patients were touch weight bearing for 2 weeks and partial until 4 weeks.

Data was collected prospectively, patients underwent clinical review and completed Lysholm, IKDC subjective, Tegner, KOOS and SF-36 scores pre-operatively and at 6 monthly intervals. One patient has been excluded from the analysis as she emigrated and was lost to follow up. The remaining 10 patients (mean age 35 years (21–49)) had defects on the medial femoral condyle (n=6), lateral femoral condyle (n=3), and lateral trochlea (n=1). Patients received one (n=5), two (n=3) or three (n=2) plugs and four were primary procedures, and six revision procedures (1 failed OATS, 5 failed microfracture). Eight implantations were performed arthroscopically and, and two were mini-open. All patients were reviewed at 12 months, five were reviewed at 18 months and four have also been reviewed at 24 months.

Statistically significant improvements from mean pre-operative scores are seen at 12 months; Lysholm (48.3 to 71), IKDC Subjective (37.7 to 65.1), Tegner (2.4 to 4.6), SF36 physical (39.5 to 50.3) and all components of KOOS. These improvements are maintained at the latest follow up. MRI evaluation including T2 mapping demonstrates reformation of the subchondral lamina, resorption of the graft and a similar signal from neo-cartilage as that of adjacent native cartilage.

TruFit plugs offer an exciting novel solution for cartilage repair in the knee with advantages of low morbidity and rapid recovery without the need for prolonged non-weight bearing. The implant may be suitable for small lesions only and further prospective study is required to establish long-term outcome.

Introduction: Treatment of dual compartment osteoarthritis remains controversial, with conjecture over whether Uni-Compartmental (‘UKA’) or Total Knee Arthroplasty (‘TKA’) is more appropriate for patients with patello-femoral disease. The ‘Journey Deuce’ 2/3 Knee Arthroplasty (‘2/3 Knee’) (Smith & Nephew) is a bi-cruciate retaining prosthesis designed to treat this subgroup of patients with both antero-medial and patello-femoral disease.

We have conducted a prospective, observational clinical trial of 34 patients with dual compartment osteoarthritis of the knee treated with a 2/3 Knee.

Aims: To assess the safety and clinical efficacy outcomes of the 2/3 Knee.

Method: All patients pre-op leg alignment films, as well as MRI or arthroscopy to confirm the inclusion criteria of dual compartment osteoarthritis with a preserved lateral compartment and intact cruciate ligaments. All operations were performed by a single surgeon (DW) using computer assisted surgery (CAS) and a minimally invasive technique (MIS) at a local university affiliated private hospital (HPH).

Exclusion criteria included obesity, inflammatory arthritis and a fixed flexion deformity > 10 degrees.

Subjective outcome measures included Oxford Knee Scores (OKS) and EQ-5D Scores. RSA beads were implanted at surgery to detect loosening, micro-motion and prosthesis wear. Gait analysis was conducted at 1 year post op in a subgroup of patients.

Results: Follow up ranged from 6 months to 2 years. There have been no early failures requiring complete revision. The first 23 knees (18 patients) did not have primary resurfacing of the patella. Some of these patients suffered palpable and audible patello-femoral crepitus, with a subgroup (17%, 4 knees-3 patients) having associated anterior knee pain. This subgroup had revision procedures to resurface their patellae with resolution of their symptoms. All subsequent patients have had primary patella resurfacing with no incidence of Significant crepitus or anterior knee pain.

The patients have recorded Significant improvement in their Oxford Knee Scores at 6 months (mean reduction all patients: 17.3, resurfaced 20).

Early RSA results have not detected Significant migration to indicate early loosening. Gait analysis has shown that patients return to approximate normal rather than pre-operative gait.

Conclusions: Although longer follow up is required the 2/3 Knee appears a safe and effective treatment option for patients with dual-compartment osteoarthritis; with rehabilitation, function and gait tending towards that seen in UKA rather than TKA.

It is essential that patients undergo primary patella resurfacing to prevent crepitus and associated anterior knee pain.

A study comparing clinical outcomes of 2/3 Knee vs TKA is underway at our institution.

The purpose of this study was to assess the accuracy of a modified version of the pivot shift test in detecting ruptures of the anterior cruciate (ACL) ligament.

Methods: Two groups of patients aged 18 to 50 years were recruited from operating theatre lists examined at a check and consent clinic. One of the groups had ACL deficient knees and the control group had intact ACL, later proven at arthroscopy. A total of 48 independent examinations, 26 with ACL rupture and 22 without, were undertaken by a consultant or registrar proficient in the modified version of the pivot shift test. At the start of the consultation the examiner, who was blinded to the operation that the patient was listed for and to the patient’s history, performed the modified pivot shift test only. The result of the test was reported as positive or negative for ACL rupture to the study co-ordinator before the examiner continued with the consultation.

Results: Of the 26 examinations of ACL deficient knees, 22 were reported as positive and four negative for ACL rupture using the pivot shift test only. Of the 22 examinations of ACL intact knees one was reported as positive for ACL rupture and 21 as negative. This gives a specificity and sensitivity of the modified version of the pivot shift test as 95.5% (95% CI 75.1–99.8%) and 84.6% (95%CI 64.3–95.0%) respectively.

Conclusion: The modified pivot shift test is an accurate test for the detection of ACL rupture. Our modified pivot shift test compares favourably with data from previous accuracy studies of previously described versions of the pivot shift test. We now plan to assess the accuracy of the modified pivot shift test when carried out by medical students and junior doctors.

Objectives: To compare the results of various surgical approaches to the knee in primary arthroplasty surgery.

Design: Systematic review with meta-analysis

Data Sources: Cochrane Bone, Joint, and Muscle Trauma group trials register (2007), Cochrane central register of controlled trials (Cochrane Library issue 2, 2007), Medline (1950 to February 2007), Embase (1974 to February 2007), CINAHL (1982 to February 2007), Pubmed, SCOPUS and ZETOC. If data was insufficient trialists were contacted via telephone, email or letter.

Review methods: Randomised and quasi-randomised controlled trials comparing surgical approaches to the knee in patients undergoing primary arthroplasty surgery.

Results: Twenty-three randomised, controlled trials (1282 patients, 1490 TKAs) were included.

Midvastus vs Medial Parapatellar approach: Quadriceps function in the early post operative period was better preserved in the MV group. Post operative pain, blood loss and the need for LRR tended to be lower in the MV group. There was no difference in ROM, hospital stay, knee scores, complications or radiological alignment.

Conclusions: Approaches preserving the quadriceps tendon improve the early extensor mechanism function and tend to decrease the need for LRR. Combined with a decrease blood loss and postoperative pain, these approaches improve early rehabilitation and allow for a more rapid recovery of knee function. However, these early improvements fail to provide any long term benefit, do not improve knee scores, or decrease the length of hospital stay.

Aims: To study the outcome of lumbar spinal fusions in patients with chronic lower back pain due to degenerative spinal disorders. Methods: 85 patients with DSD’s, a mean age of 46.4 years, back pain for at least 2 years (mean=7.7years) and failed conservative treatment for at least 1 year were admitted to the study. Questionnaires recorded socio-demographic characteristics; changes in pain, clinical findings, disability (Oswestry (ODI)), employment, radiographic fusion, patient satisfaction and complications. All patients had 3, 6, 12 and 24-month follow-ups. Results: There were 37 males (44.9years) and 48 females (47.6 years) with a mean BMI of 24.8; 49% were smokers. Pain improved significantly at 3months (p< 0.001); no deterioration at 2 years with 38.4% having no back pain. Motor (p< 0.01), sensory (p< 0.05) and Oswestry Disability (0.001) improved significantly at 3 months and continued throughout. Unemployment improved significantly 30.4% to 16.5% at 2 years (p< 0.04). Radiographic fusion occurred in 91.8%, instrument failure in 11.8% and 9.4% required re-operation. Patient satisfaction revealed a significant increase in excellent (p< 0.02) and poor (p< 0.03) results. Instrument failure correlated strongly with ODI (r=0.94, p< 0.04). No other significant correlations. Conclusions:With the correct patient selection, lumbar fusions for DSD’s lead to a significantly improved outcome at 2 years, with an acceptable complication rate. There is no correlation between radiographic fusion and outcome, but instrument failure leads to significantly worse outcome

Aims: To investigate the functional outcome with different autologous bone graft weights in posterolateral lumbar spine instrumentation for DSD’s. Methods: A total of 79 patients (mean age of 47.2) with chronic lower back pain for at least 2 years, with at least 1 year of failed conservative treatment and who were undergoing pos-terolateral spinal instrumentation for DSD’s were admitted to the trial. Patients were randomised into three groups to receive bone graft weights of 25g (Group A=26 patients), 50g (Group B=30 patients) and 100g (Group C=23 patients) per segment. Pain, clinical characteristics, disability (Oswestry), radiographic fusion, patient satisfaction and complications were recorded at 3, 6, 12 and 24-month follow-ups. Results: At 2 years, Group B (50g) had a significantly improved Oswestry Index, pain intensity, motor and sensory changes, and overall patient satisfaction than Group C (100g), which was significantly better than Group A (25g). There was no correlation between bone graft weight and radiographic fusion, between fusion and outcome, nor smoking and fusion or bone graft weight. Complications were similar. Conclusions: Patients had significantly better functional and clinical outcomes with bone graft weights of 50g. Bone graft weights of 25g had the worse outcomes and 100g did not seem to have any beneficial affect over 50g. We recommend autologous bone graft weights of 50g per fused spinal segments in this group of surgical patients.