Preventing infections in joint replacements is a major ongoing challenge, with limited effective clinical technologies currently available for uncemented knee and hip prostheses. This research aims to develop a coating for titanium implants, consisting of a supported lipid bilayer (SLB) encapsulating an antimicrobial agent. The SLB will be robustly tethered to the titanium using self-assembled monolayers (SAMs) of octadecylphosphonic acid (ODPA). The chosen antimicrobial is Novobiocin, a coumarin-derived antibiotic known to be effective against resistant strains of Staphylococcus aureus.

ODPA SAMs were deposited on TiO₂-coated quartz crystal microbalance (QCM) sensors using two environmentally friendly non-polar solvents (anisole and cyclopentyl methyl ether, CPME), two concentrations of ODPA (0.5mM and 1mM) and two processing temperatures (21°C and 60°C). QCM, water contact angle measurements, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and temperature-programmed desorption mass spectrometry (TPD-MS) were used to characterise the ODPA SAM. A SLB with encapsulated Novobiocin was subsequently developed on the surface of the ODPA SAM using fluorescent lipids and a solvent assisted method. The prototype implant surface was tested for antimicrobial activity against S. aureus.

A well-ordered, uniform ODPA SAM was rapidly formed using 0.5 mM ODPA in CPME at 21°C during 10 min, as confirmed by high Sauerbrey mass (≍285-290 ng/cm²), high atomic percentage phosphorus (detected using XPS) and high water contact angles (117.6±2.5°). QCM measurements combined with fluorescence microscopy provided evidence of complete planar lipid bilayer formation on the titanium surface using a solvent assisted method. Incorporation of Novobiocin into the SLB resulted in reduced attachment and viability of S. aureus.

Key parameters were established for the rapid, robust and uniform formation of an ODPA SAM on titanium (solvent, temperature and concentration). This allowed the successful formation of an antimicrobial SLB, which demonstrated potential for reducing attachment and viability of pathogens associated with joint replacement infections.

The introduction of a new implant material is not without risk. A series of worst-case scenarios were developed and tested accordingly to answer questions such as: what will happen if the implant is not placed in a good orientation? What will happen to the material after a long implantation time, e.g. 20 or more years?

To reach a higher level of safety, a new approach for the preclinical testing has been taken. The vitamys® material (a novel vitamin-doped HXLPE) followed a severe pre-clinical testing protocol, including mechanical, tribological and biocompatibility testing. The testing includes a comparison of vitamys® vs. standard-UHMWPE and other HXLPE after accelerated ageing for periods equivalent to 20 and 40 years in-vivo. Hip simulator testing was done at inclination angles from 35° to 65° to assess the “forgiveness” of the material for mal-orientation.

Comparing the test results to published data, it becomes evident that the vitamin addition and the sequence of the manufacturing steps both have a significant effect of the resulting mechanical, ageing and wear properties. In contrast to UHMWPE or HXLPE without antioxidant, the vitamys material behaves in a very “forgiving” manner: Hip simulator testing of vitamys at high inclination angles and even with severely aged material revealed no increase of wear rates. The vitamys material was first introduced in a monoblock polyethylene cup with a thin Ti-particle coating, the RM-Pressfit vitamys® acetabular cup (Mathys Ltd Bettlach, Switzerland). Its first implantation occurred in Sept. 2009. Since then, a total of nearly 500 implantations have been documented in a prospective multi-centre clinical study involving 11 clinics in 5 countries (CH, DE, FR, NL and NZ).

Based on the pre-clinical testing and its first clinical experience, we have reason to believe that the RM-Pressfit vitamys® possesses interesting and unique features such as high elasticity (no stress-shielding), high ageing and wear resistance combined with clinically proven biological anchorage – making it theoretically suitable for a whole range of patients, including the young and active.

We present our mid-term results with the use of structural allografts in cases of revision of failed THA due to infection.

Eighteen patients with a deep infection at the site of a THA were treated with a two-stage revision, which included reconstruction with massive allografts. All the allografts were frozen and sterilised by gamma-irradiation. The mean age at the time of the revision was 65.9 years. A cement spacer containing 1 g of Gentamicin was used during the interval period. Parenteral antibiotics were administrated for a period of three to four weeks. Oral antibiotics were given for an average of 18 weeks. The patients were followed for a mean of 8.9 years (5.4–14.2).

Definite deep wound infection developed in one patient (5.6%), who underwent resection arthroplasty. An additional patient underwent re-revision of an acetabular component for mechanical loosening. The mean HHS improved from 34.2 points preoperatively to 70.7 points at the last review. Sixteen of the patients (88.9%) had a successful outcome. Kaplan-Meier survivorship analysis predicted 80.95% rate of survival at 14 years.

Radiographicly, all allografts were found to be united to host bone. There were no signs of definite loosening of any of the implants. The complications include one fracture and two postoperative recurrent dislocations.

The use of massive allografts in a two-stage reconstruction for infected THA gives satisfactory results and should be considered in cases complicated with severe bone stock loss, where standard revision techniques are not an option.

We have followed a consecutive series of revision hip arthroplasties, performed for severe femoral bone loss using anatomic specific proximal femoral allografts

Forty-nine revision hip arthroplasties, using anatomic specific proximal femoral allografts longer than five centimetres were followed for a mean of 10.4 years.

The mean preoperative HHS improved from 42.9 points to 76.9 points postoperatively. Six hips (12.2%) were further revised, four for non-union and aseptic failure of the implant (8.2%), one for infection (2%), and one for host step-cut fracture (2%). Junctional union was observed in 44 hips (90%). Three hips underwent re-attachment of the greater trochanter for trochanteric escape (6.1%). Asymptomatic non-union of the greater trochanter was noticed in three hips (6.1%). Moderate allograft resorption was observed in five hips (10.2%). Two fractures of the host step-cut occurred (4.1%). There were four dislocations (8.2%), two of them developed in conjunction with trochanteric escape. By definition of success as increase of HHS by 20 points or more, and no need for any subsequent re-operation related to the allograft and/or the implant, a 75.5% rate of success was found. Kaplan-Meier survivorship analysis predicted 73% rate of survival at 12 years, with the need for further revision of the allograft and/or implant as the end point.

We conclude that the good medium-term results with the use of large anatomic- specific femoral allografts justify their continued use in cases of revision hip arthroplasty with severe bone stock loss.

A radiation sterilisation dose (RSD) of 25 kGy is commonly recommended for sterilisation of allograft bone. However, the mechanical and biological performance of allograft bone is gamma dose-dependent. Therefore, this study aimed to apply Method 1 – ISO 11137–2: 2006 to establish a low RSD for frozen bone allografts. Two groups of allograft bones were used: 110 femoral heads (FH) and 130 structural and morselized bones (SMB).

The method included the following stages: bioburden determination using 10 FHs and 30 SMBs; verification dose selection using table six in the ISO standard and bioburden; the verification dose was used to irradiate 100 samples from each group; then irradiated bone segments were tested for sterility. The criterion for accepting the RSD as valid is that there must be no more than two non-sterile samples out of 100. The radiation sterilisation dose is then established based on table five, ISO 11137– 2: 2006.

The bioburden of both types of frozen allograft was zero. The verification dose chosen was 1.3 kGy. Two hundred bone segments were irradiated at 1.3 kGy. The average delivery gamma dose was 1.23 kGy (with minimum dose of 1.05 kGy maximum dose of 1.41kGy), which is acceptable according to the ISO standard. Sterility tests achieved 100% sterility. Accordingly, 11 kGy was established as a valid RSD for those frozen bone allografts. A reduction in the RSD from 25 kGy to 11 kGy will significantly improve bone allograft mechanical and biological performance because our data show that this dose level improves the mechanical toughness and osteoclast activity of the allograft by more than 10 and 100 percent, respectively, compared with bone allografts irradiated at 25 kGy.

A low RSD of 11 kGy was established for allograft bones manufactured at Queensland Bone Bank by applying dose validation method 1 (ISO 11137.2-2006) that is internationally accepted.

It is not known if the radiation sterilisation dose (RSD) of 25 kGy affects mechanical properties and biocompability of allograft bone by alteration of collagen triple helix or cross-links. Our aim was to investigate the mechanical and biological performance, cross-links and degraded collagen content of irradiated bone allografts.

Human femoral shafts were sectioned into cortical bone beams (40 × 4 × 2 mm) and irradiated at 0, 5, 10, 15, 20, and 25 kGy for three-point bending tests. Corresponding cortical bone slices were used for in vitro determination of macrophage activation, osteoblast proliferation and attachment, and osteoclast formation and fusion. Subsequently, irradiated cortical bone samples were hydrolised for determination of pyridinoline (PYD), deoxypyridinoline (DPD), and pentosidine (PEN) by high performance liquid chromatography (HPLC) and collagen degradation by the alpha chymotrypsin (ï_jCT) method.

Irradiation up to 25 kGy did not affect the elastic properties of cortical bone, but the modulus of toughness was decreased from 87% to 74% of controls when the gamma dose increased from 15 to 25 kGy. Macrophages activation, the proliferation and attachment of osteoblasts on irradiated bone was not affected. Osteoclast formation and fusion were less than 40% of controls when cultured on bone irradiated at 25 kGy, and 80% at 15 kGy. Increasing radiation dose did not significantly alter the content of PYR, DPD or PEN but increased the content of denatured collagen.

Cortical allografts fragility increases at doses above 15 kGy. Decreased osteoclast viability at these doses suggests a reduction in the capacity for bone remodelling. These changes were not correlated with alterations in collagen cross-links but in degradation to the collagen secondary structure as evidenced by increased content of denatured collagen.

Antero-posterior (AP) pelvis and lateral x-rays are routinely prescribed for the positional diagnosis of proximal femoral fractures, however; the usefulness of the lateral x-ray has not been previously presented in the literature. In addition, the clinical advantage of internally rotated AP views has also not been tested. This study aims to define the value of the lateral x-ray, and the internally rotated AP view, in the assessment and treatment planning of proximal femoral fractures.

X-rays from 359 consecutive patients with proximal femoral fractures were divided into: ‘un-positioned’ AP (greater trochanter overlying the lateral femoral neck), clear neck AP (internally rotated to show the lateral femoral neck), and lateral views. Three blinded reviewers independently assessed the x-rays in sequence and noted the positional diagnosis and displacement. This was then compared with the intra-operative diagnosis used as gold standard.

The addition of a lateral x-ray to an AP view significantly increased the rate of the correct diagnosis made by the reviewers when compared to an AP view alone, in intracapsular fractures only (p < 0.013), but not for extracapsular fractures (p = 0.27).

The use of clear neck AP views did not increase the rate of correctly diagnosing the type of fracture when compared to unpositioned AP views. This applies for both intracapsular (p = 0.57), and extracapsular fractures (p < 0.823).

Although orthopaedic rote dictates that every fracture should be visualised in two views, this study has shown with that for the majority of hip fractures one view is adequate and safe. The lateral x-ray is only required for intracapsular fractures that appear undisplaced on the AP view and should not be performed routinely. Specially positioned AP views are not required and should be avoided due to the unnecessary pain caused and the needless cost.

Universal neonatal screening of developmental dysplasia of the hip (DDH) remains controversial and a few centres have adapted this practice in the United Kingdom. Our institute has established a DDH screening programme over the last 19 years. The following shows our result after a recent change in our screening programme protocol. All infants born in Coventry are screened for DDH by a clinical examination and ultrasound scan (USS). 5,084 babies were born over a 12-months period. Normal examination and USS were detected in over 90% of the cases. Abnormality detected through either clinical examination or USS was referred to a special orthopaedic/USS clinic.

However, in the majority of the cases, subsequent assessments were normal and only 23 babies required treatment. In these cases, the majority had not shown any signs of clinical abnormality. However, serial USS had shown persistent abnormality of at least Graf grade II or higher. The average time from birth to a treatment with a Pavlik Harness was 35 days and the average duration of a treatment was 48 days. Apart from one case, all the babies were treated successfully. The unsuccessful cases had a Graf grade IV at the presentation and had shown no sign of improvement on sequential USS. No complications were noted.

While the sensitivity of detecting DDH through clinical examination remains poor, USS has become an essential tool in our screening programme. Many initial abnormalities are secondary to hip immaturity and they tend to resolve. Those with clinical instability and persistent USS Graf grade II or higher should be treated with early Pavlik Harness. Early detection has led to better results than late diagnosis, and in addition to this, the overall number of operations required could be reduced. Yet, the need for a major surgical intervention has been all but eliminated.

We have followed a consecutive series of forty-nine revision hip arthroplasties (45 patients), performed for severe femoral bone loss using anatomic specific proximal femoral allografts longer than five centimetres. The patients were followed for a mean of 10.4 years, with a five year minimum follow-up. The mean preoperative Harris Hip Score improved from 42.9 points to 76.9 points postoperatively, an average improvement of 33.8 points. Six hips were further revised, for a failure rate of 12.2%, four for non-union and aseptic failure of the implant (8.2%), one for infection (2%), and one for host step-cut fracture (2%). Junctional union was observed in 44 hips (89.8%). Three hips underwent re-attachment of the greater trochanter for trochanteric escape (6.1%). Asymptomatic non-union of the greater trochanter were noticed in three hips (6.1%). Moderate allograft resorption was observed in five hips (10.2%), non were full-thickness graft resorption. Two fractures of the host step-cut occurred (4.1%). There were four dislocations (8.2%), two of them developed in conjunction with trochanteric escape. By definition of success as increase of HHS by 20 points or more, and no need for any subsequent re-operation related to the allograft and/or the implant, a 75.5% rate of success was found. Kaplan-Meier survivorship analysis predicted 73% rate of survival at 12 years, with the need for further revision of the allograft and/or implant as the end point. We conclude that the good medium-term results with the use of large anatomic-specific femoral allografts justify their continued use in cases of revision hip arthroplasty with severe bone stock loss.

Introduction: Total hip arthroplasty (THA) has proven to be a highly successful procedure, but with its increased use there are an increasing number of joints requiring revision. A number of those patients requiring revision present with a severe loss of femoral bone stock around the failed femoral hip implant, which makes conventional revision techniques difficult or impossible.

Materials and Methods: We have followed a consecutive series of forty-nine revisions THA (45 patients), performed for severe femoral bone loss using anatomic specific proximal femoral allografts longer than five centimetres. The patients mean age at the time of the index surgery was 63 (32–86) years. The patients were followed for a mean of 8.4 (5.2–16.6) years, with a five-year minimum follow-up.

Results: The mean Harris Hip Score improved from 42.9 points preoperatively to 76.9 points at the last review. Fort-three of the hips (88%) had a successful outcome. Kaplan-Meier survivorship analysis predicted 83% rate of survival at 17 years. Six hips (12.2%) were further revised: four for non-union and aseptic failure of the implant, one for infection, and one for host step-cut fracture. Radiographicly, junctional union was observed in 44 hips (90%). Asymptomatic non-union of the greater trochanter were noticed in three hips (6.1%). Moderate allograft resorption was observed in five hips (10.2%), none were full-thickness graft resorption. The complications include trochanteric escape in three hips, host step-cut fractures in two hips, and four dislocations.

Conclusion: We conclude that the good medium-term results with the use of large anatomic-specific femoral allografts justify their continued use in cases of revision hip arthroplasty with severe bone stock loss.

The Exeter Universal Stem has limited published data with greater than 10 year results, this is from specialist orthopaedic centres using predominantly posterior approach. Our aim was to establish whether the published results could be reproduced in a District General Hospital (DGH) using a Hardinge approach.

We reviewed 131 consecutive primary THRs implanted into 127 patients between 1995 and 1997 (minimum10 year follow up). Surgery was performed through a Hardinge approach using the Exeter universal stem with the Ogee Elite acetabular component.

Outcome was assessed by patient review, completing an Oxford Hip Score (OHS) and reviewing the hospital records. Deceased patients’ hospital records were reviewed and their GP questioned.

5 of 131 hips required revision: 3 for infection at 4–7 years following implantation and 2 for aseptic loosening (one acetabulum only, one both components). There have been no cases of dislocation or sciatic nerve palsy. Kaplan-Meir survival analysis demonstrates ten year survival as follows: 95.3% survival with revision for any cause as the end point; 98.9% with revision for aseptic loosening of the stem as the endpoint, 98.1% with revision for aseptic loosening of the acetabular component as the endpoint, 97.2% with revision for infection as the endpoint.

The mean OHS was 22.7 (median =20, interquartile range 15–26).

This is the first series to report on the 10 year results with the Exeter Universal stem used exclusively in conjunction with the Ogee Elite acetabular component. It is also the first series to report the 10 year results using only the Hardinge approach. Our findings are the first to show that the Exeter universal stem in combination with the Ogee Elite acetabular component can be inserted through a Hardinge approach in a DGH setting with results comparable to surgery performed in a specialist unit and through a posterior approach.

Hip and knee arthroplasty has been associated with relatively high rates of thromboembolic events and the majority of UK orthopaedic surgeons use at least one form of prophylaxis. Of the many different subgroups of thromboembolic rates that are commonly presented in the literature, symptomatic proximal deep vein thrombosis (spDVT) and fatal pulmonary embolism (fPE) are perhaps the most important clinical outcomes.

To determine the effectiveness of common chemical and mechanical prophylactic methods in preventing spDVT and fPE in patients undergoing primary hip and knee arthroplasty. A systematic review of the literature from 1981 to December 2002 was performed. Predetermined inclusion and exclusion criteria were applied. Studies where more than one method of prophylaxis was used were excluded from analysis. For each individual method of prophylaxis, data was extracted, combined and converted to give estimates of the rates of spDVT, fPE and major bleeding events. Absolute risk reduction estimates for spDVT, fPE and major bleeding events were calculated by comparing the thromboembolic rates for each method of prophylaxis with using no prophylaxis of any kind.

992 studies were identified of which 162 met the inclusion criteria. No method of prophylaxis was statistically significantly more effective at preventing spDVT and fPE than using nothing. There were at least as many major bleeding complications as spDVTs. The number of fPEs prevented was very small.

When complications such as major bleeding are considered, the evidence behind the use of any prophylaxis is unconvincing.

Aims: The re-dislocation rates in adults (< 30 years) in the initial 12 months after FAT (first,anterior,traumatic) shoulder dislocations treated non-operatively vary from 25% to 95%. Some surgeons advocate early arthroscopic surgery following such dislocations as this appears to reduce recurrent instability. The purpose of this study was to establish if arthroscopic surgery reduces the incidence of recurrent instability after such dislocations when compared to non-operative treatment.

Material and Methods: Specific search terms were used to retrieve relevant studies from MEDLINE, EMBASE, and CINAHL extending from 1966 to October 2003. Guidelines for reporting of meta-analysis, adapted from QUOROM statement were followed. Adults under 30 years of age, with clinical and radiological confirmation of anterior dislocation following trauma with a minimum follow-up of 12 months were included. Patients with previous shoulder problems, generalised joint laxity, neurological injury, impingement and a history of substance abuse were excluded.

Results: 13 studies involving 433 shoulders were reviewed.

Group A included 84 shoulders treated by arthroscopic lavage without stabilisation. There were no subluxations. The re-dislocation rate was 14.3% (12/84).

Group B had 179 shoulders treated by arthroscopic stabilisation. The incidence of subluxation was 5.02% (9/179) and dislocation was 6.14% (11/179).

Recurrent instability (subluxation /dislocation) following arthroscopic lavage (12/84 – 14.3%) was significantly higher than after arthroscopic stabilisation (20/179 – 11.2%). [p= 0.04, Relative risk = 2.32, 95% CI: 1.07 to 5.05]

Group C involved 170 shoulders treated non-operatively. The incidence of subluxation was 8% (12/150) and dislocation was 62% (93/150). The overall incidence of recurrent instability was 70% (119/170).

Recurrent instability following arthroscopic intervention (32/263 – 12.2%) was significantly lower than following non-operative treatment (119/170 – 70%) [p< 0.0001, Relative risk = 0.17, 95% CI: 0.12 to 0.24].

Conclusion: Early arthroscopic surgery reduces recurrent instability during the initial 12 months after FAT shoulder dislocation in young adults (< 30 years) when compared to non-operative treatment. Arthroscopic treatment should be offered to young, athletic patients especially those involved in contact sports or defence personnel, who are at a high risk of recurrent instability after initial shoulder dislocation. Further randomised control trials reporting on a larger number of patients with a minimum follow-up of 5 years are required before one can draw firm conclusions on the ability of arthroscopic intervention to influence the natural history of FAT shoulder dislocation.

Aim: The re-dislocation rates in adults (< 30 years) in the initial 12 months after first, anterior, traumatic (FAT) shoulder dislocations treated non-operatively vary from 25% to 95%. The purpose of this study was to establish if arthroscopic surgery reduces the incidence of recurrent instability (failure) after such dislocations when compared to non-operative treatment.

Material and Methods: Specific search terms were used to retrieve relevant studies from various databases extending from 1966 to May 2004. Guidelines for reporting of meta-analysis, adapted from QUOROM statement were followed.

Results: 13 studies involving 433 shoulders were reviewed. Group A included 84 shoulders treated by arthroscopic lavage without stabilisation. There were no subluxations. The re-dislocation rate was 14.3% (12/84). Group B had 179 shoulders treated by arthroscopic stabilisation. The incidence of subluxation was 5.02% (9/179) and dislocation was 6.14% (11/179). Failure following arthroscopic lavage (12/84 – 14.3%) was significantly higher than after arthroscopic stabilisation (20/179 – 11.2%). [p= 0.04, Relative risk = 2.32, 95% CI: 1.07 to 5.05]. Group C involved 170 shoulders treated non-operatively. The incidence of subluxation was 8% (12/150) and dislocation was 62% (93/150). The overall incidence of failure was 70% (119/170). Failure following arthroscopic intervention (32/263 – 12.2%) was significantly lower than following non-operative treatment (119/170 – 70%) [p< 0.0001, Relative risk = 0.17, 95% CI: 0.12 to 0.24].

Conclusion: Early arthroscopic surgery appears to reduce recurrent instability during the initial 12 months after FAT shoulder dislocation in young adults (< 30 years) when compared to non-operative treatment. Arthroscopic stabilisation may be considered for young, athletic patients and those involved in contact sports or defence personnel, who are at a high risk of recurrent instability after FAT shoulder dislocation. RCTs reporting on a larger number of patients with a minimum follow-up of 5 years are required before one can draw firm conclusions on the ability of arthroscopic intervention to influence the natural history of traumatic anterior shoulder dislocation.

Aims: Musculo-skeletal complaints comprise a significant proportion of General Practitioner workload. The aim of this study was to assess whether the training of GP’s is satisfactory given their exposure to orthopaedics and trauma in practice.

Methods: A postal questionnaire was sent to 200 local General Practitioners requesting information on their training in musculo-skeletal conditions.

Results: The response rate was 58%. The reported estimated proportion of musculo-skeletal problems varied between 10% and 60 %. Only 33% of General Practitioners had any formal post graduate training in trauma and orthopaedics. Experience in the related specialities of rheumatology was 12% and A+E 69%. 35% of responding General Practitioners reported a specialist interest in musculo-skeletal conditions although less than 2% have any postgraduate qualifications in this area.

Only 23% of GP’s thought that their training in orthopaedics and trauma was adequate .85% felt that they would benefit from further training. 80% of these felt that clinical teaching would be the best way to achieve this.

Conclusions: Musculo-skeletal problems comprise a significant proportion of General Practice workload. Despite this fact formal training in trauma and orthopaedics received by GP’s is minimal. 77% of GP’s feel that their training in the treatment of musculo-skeletal conditions is inadequate and 85% would like further training.

Introduction Recent publications have confirmed that as many as one in four retrieved femoral heads can be significantly contaminated with potential pathogens. Reports from the Centre for Disease Control in Atlanta, Georgia have described fatal outcomes from the unwanted transmission of bacterial disease with inadequately processed allograft materials. Surgeons requesting non terminally sterilised bone refer to theoretical biological and biomechanical deleterious effects of gamma irradiation. This study examines the accuracy of those claims.

Methods We have investigated the effects of varying levels of gamma irradiation (0kG, 15kG and 25kG) on the biological competence of morsellised allograft bone and its associated biomechanical impaction qualities. The biological study has used an in vivo model (nude rat) to quantify the effects of gamma irradiation on osteoinduction and osteoconduction. An in vitro impaction routine has been used to measure compaction, impaction and stiffness in the allograft product.

Results There were no statistical differences in the biomechanical or biological properties of the 0kG and 15kG specimens (P< 0.05). Gamma irradiation at the 25kG level resulted in an allograft product of higher biomechanical stiffness, unchanged osteoinductivity and slightly lower osteoconductivity (P< 0.05).

Conclusion Terminal gamma irradiation of 15kG reduces the risk of bacterial transmission with allograft products. It does not alter the efficacy of the allograft at biological and biomechanical levels. Gamma irradiation represents the mainstay of sterilisation of musculoskeletal allograft materials. Australian practices appear to be leading an international trend.

In relation to the conduct of this study, one or more the authors have received, or are likely to receive direct material benefits.

Introduction The tibial component of a total knee arthroplasty is subjected to eccentric medial and lateral plateau tibial loading during various phases of stance. The resultant coronal planar tilting forces may provoke early subsidence and loosening. The addition of a long non cemented stem is postulated to act as an outrigger, diminishing the rate of aseptic loosening.

Methods Two hundred and thirteen primary total knee arthroplasties using proximally cemented tibial components with long non cemented Pressfit stems have been reviewed. Stem lengths varied from 110 mm to 140 mm. Patients were seen at an average of 8.7 years after surgery (two to 13 years) and were assessed using the Knee Society (IKS) pain and function scores, IKS radiographic analysis and Short Form-12 and Western Ontario Macmasters University Osteoarthritis Index (WOMAC questionnaires).

Results Average range of motion was 115° at latest follow-up. The average IKS pain and function scores at the time of assessment were 90 and 89 respectively. Radiographic assessment revealed no case of tibial implant loosening. Kaplan-Meier survivorship was 98.6% at 13 years.

Conclusions The results lend clinical support to the known theoretical advantages of adding a stem to the tibial component in primary knee arthroplasty.

In relation to the conduct of this study, one or more the authors have received, or are likely to receive direct material benefits.

There has been significant advancement in the principles and practices of Tissue Banking in Australia over the last two years. Those advances relate to scientific development, regulatory modulation and inter-relationships between both Federal and State governments. Licencing issues

The Therapeutic Goods Administration of the Federal Department of Health and Aged Care

Aseptic loosening which may lead to osteolysis and massive loss of bone, remains the major cause of failure after total hip arthroplasty. Reconstruction of acetabular bone stock defects by means of bone grafting is mandatory to create a stable construct to support the cup, recreate anatomy, and restore lower limb length. Numerous classification systems for acetabular bone stock deficiencies have been recommended to date. The one proposed by the American Academy of Orthopedic Surgeons (AAOS) is the most comprehensive and most consistent. This system classifies acetabular defects into segmental (type 1), cavitary (type 2), combined segmental and cavitary (type 3), pelvic dissociation (type 4), and hip fusion (type 5).

The aim of this study is to present a long term review of our experience with reconstruction of acetabular bone stock deficiencies in conjugation with revision hip arthroplasties using bone grafting, based on the AAOS classification system.

Between 1987 and 1998, 88 revisions using bone grafting to reconstruct acetabular bone stock defects were performed. Of them 4 patients were classified as type 1, 47 as type 2, 29 – type 3, and 8 as type 4. The mean follow-up period was 8 years (range: 2–3 years).

The mean Haris Hip Score improved from 35 points preoperatively to 75 postoperatively. All patients improved.

The complications included nonunion in 5 cases, joint instability in 6 cases, graft lysis in one case, and neurologic injury in one case. Five cups were considered radiographicaly loose. One case was infected.