Introduction. Total hip arthroplasty (THA) using short design stem is surging with increasing movement of minimally invasive techniques. Short stems are easier to insert through small incisions preserving muscles. We have used these types of short stems since 2010. Almost all of the patients have shown good clinical results. However, two patients developed fatigue fractures on femurs post operatively. We have reviewed the clinical and radiographic results of these patients. Patients and methods. From April 2010, we have performed 621 THAs with short design stems, Microplasty. R. , Biomet, using a muscle preservation approach, the Direct Anterior Approach (DAA). The age ranged from 31 to 88 years old. Case1: 56y.o. male, BMI 23.1kg/m. 2. Preoperative diagnosis was bilateral osteoarthritis. Simultaneous THAs were performed on bilateral hips. He was allowed to bear as much weight as he could tolerate using an assistive device immediately after surgery, and followed standard hip precautions for the first 3 weeks. He was discharged from hospital seven days after surgery and returned to his job two weeks after surgery. He noticed sudden left thigh pain three weeks after surgery without any obvious cause. Crutches were recommended to partially bear his weight. Six weeks after surgery, a fracture line became visible on the radiographs and new callus formation also became visible. Three months after surgery, he felt no pain and was able to walk without any crutches. Case2: 66y.o. female, BMI 27.5 kg/m. 2. Preoperative diagnosis was bilateral osteoarthritis. THAs were performed on the hips at a six month interval. The right hip was operated on first, followed by the left hip. She was discharged from hospital four days after surgery and returned to her job six weeks after surgery. Two months later after left hip surgery, she suddenly felt pain on her left femur without any obvious cause, and was unable to walk. Three weeks later, X-rays showed fatigue fracture lines and new callus formations. After two or three months using crutches, her pain improved and X-rays showed good callus formation and no stem subsidence. Discussions. Several reports showed insufficiency fractures of the pelvis following THA. But most of them occurred due to repetitive stress on fragile bones. But our cases showed no evidence of osteoporosis. They had no history of trauma. But they had some points in common, which were they were bilateral cases and their BMI were not low. The incident rate of fatigue fractures of femur with this short stem THAs was 0.3% in our cases. We suggested that one of the causes of these fatigue fractures was the shortness of the stems. The shortness of the stems concentrate the body weight to limited contact area of the femur, and the stress causes the fatigue fractures. We should consider the risk of fatigue fractures on the patients who are operated on bilaterally. However these two patients showed good callus formations and no stem subsidence after a few weeks of partial weight bearing

The incidence and long-term outcome of undisplaced fatigue fractures of the femoral neck treated conservatively were examined in Finnish military conscripts between 1970 and 1990. From 106 cases identified, 66 patients with 70 fractures were followed for a mean of 18.3 years (11 to 32). The original medical records and radiographs were studied and physical and radiological follow-up data analysed for evidence of risk factors for this injury. The development of avascular necrosis and osteoarthritis was determined from the follow-up radiographs and MR scans. The impact of new military instructions on the management of hip-related pain was assessed following their introduction in 1986. The preventive regimen (1986) improved awareness and increased the detected incidence from 13.2 per 100 000 service-years (1970 to 1986) to 53.2 per 100 000 (1987 to 1990). No patient developed displacement of the fracture or avascular necrosis of the femoral head, or suffered from adverse complications. No differences were found in MRI-measured hip joint spaces at final follow-up. The mean Harris Hip Score was 97 (70 to 100) and the Visual Analogue Scale 5.85 mm (0 to 44). Non-operative treatment, including avoidance of or reduced weight-bearing, gave favourable short- and long-term outcomes. Undisplaced fatigue fractures of the femoral neck neither predispose to avascular necrosis nor the subsequent development of osteoarthritis of the hip

Introduction: We evaluated the follow-up results of subchondral fatigue fractures of the femoral head. Methods: Between July 1999 and August 2005, 10 male patients presented with a collapsed subchondral fatigue fracture of the femoral head. The flattening of the femoral head was mild in 4 cases, moderate in 3 cases and severe in 3 cases. Three cases were misdiagnosed as osteonecrosis and since treated with multiple drillings or bone grafts. One case was treated with impaction bone grafting. The remaining cases were treated non-operatively. All patients were followed more than 2 years after onset of hip pain. Results: At the latest follow-up, no patient had remarkable pain or disability limiting daily activity. Degenerative changes of Tönnis grade 1 were observed in 5 cases. Discussion: Unlike collapsed osteonecrosis, collapsed subchondral fracture of the femoral head had a benign clinical course

1. Thirty-seven specimens of the proximal third of the human femur were subjected to cyclically varying loads applied in a physiological direction to the femoral head, having maximum values of from four to thirteen times body weight. 2. Ten of these specimens sustained subcapital fractures of the femoral neck after numbers of cycles of loading varying from 123 to 8,193. 3. The maximum value of cyclic load needed to give fatigue fracture after 10,000 or fewer cycles was found to vary from about twelve times the body weight at ages twenty to fifty to about five times the body weight at age seventy or more. 4. In youth and in middle age the load levels mentioned above are greater than those encountered in normal living, but are comparable to those which may be applied to the femoral head during activities known to produce "fatigue" fractures clinically in young adults. 5. In the elderly the load levels mentioned above are within the range that can be applied in normal living. It is inferred that some femoral neck fractures in the elderly may be fatigue fractures caused by the cyclic loading of normal walking

Introduction: Stress fracture of the femoral head is a rare condition and usually occurs in people with poor bone quality as an insufficiency fracture. We evaluated the clinical aspects of subchondral fatigue fractures of the femoral head (SFFFH) that occurred in young healthy people. Materials and Methods: Between January 1998 and November 2001, 7 cases of SFFFH in 5 patients were treated. The characteristics of this condition were ascertained by assessing the clinical course and findings of radiographs, bone scintigrams, and magnetic resonance (MR) images. Results: All patients were male military recruits in their early twenties. Pain developed within 6 months after recruitment. On initial radiographs, definite abnormal findings were observed in 3 hips of 2 patients. In 2 of them, the femoral head was markedly collapsed. In the other 4 hips, no definite abnormal findings were noticed. The bone scintigrams showed increased radionuclide uptake in the femoral head. MR images demonstrated localized abnormal signal intensity areas (bone marrow edema pattern) in the femoral head. In all cases, MR crescent signs were observed. In the cases without collapse of the femoral head, the pain decreased gradually and disappeared completely in 6 months with improving findings on follow-up MR images. The collapsed cases needed surgical treatment: total hip arthroplasty or strut iliac bone grafting. Discussion: When a military recruit or an athlete is complaining of hip pain, a high index of suspicion for SFFFH is necessary to prevent the collapse of the femoral head. Bone scintigrams are of great value as a screening tool. Osteonecrosis of the femoral head can be differentiated by the findings on MR images

Femoral component fracture is a rarely reported but devastating complication of total knee arthroplasty. It has occurred most frequently with Whiteside Ortholoc II replacements uncemented knee replacements. Presentation may be with acute pain, progressive pain or returning deformity. It occurs more commonly in the medial condyle of the femoral component. It is rarely seen in cemented replacements. All currently available literature describing fractures of condylar replacements, both cemented and uncemented. Predisposing factors include varus deformity either pre or post operatively. The mechanism of failure is thought to be failure of the infiltration of bone into the replacement. This is often due to polyethylene wear or metallosis causing abnormal tissue reaction with or without osteolysis. We present the case of a fractured Press Fit Condylar (PFC) cemented implant (DePuy, Johnson&Johnson, Raynham, Massachusettes, USA) affecting the medial condyle. To our knowledge this is only the third reported case of fracture in a PFC implant, and the first in a cemented PFC implant. Our patient was a 64 year old male who presented with unresolving knee pain post total knee arthroplasty, caused by fatigue fracture of the medial condyle of the femoral component. This was identified as loosening on plain radiographs and replaced with a revision prosthesis with a good post operative result. Given our aging population and with the increase of joint arthroplasty, this case sheds light on a potentially under recognised and increasingly important cause of knee pain following arthroplasty

Aims

The risk of mechanical failure of modular revision hip stems is frequently mentioned in the literature, but little is currently known about the actual clinical failure rates of this type of prosthesis. The current retrospective long-term analysis examines the distal and modular failure patterns of the Prevision hip stem from 18 years of clinical use. A design improvement of the modular taper was introduced in 2008, and the data could also be used to compare the original and the current design of the modular connection.

1. A hope expressed in 1940, that further cases of spontaneous fracture of the lowest third of the apparently normal fibula would be described, has been fulfilled. The literature is here reviewed. Five further personal cases are added. 2. The clinical and radiographic features, diagnosis, treatment and results are considered in the light of the information so far available. Special note is made of misleading freedom of ankle and tarsal movements and the occasional absence of tenderness. 3. It is established that fractures of the lowest third occur particularly in two groups of subjects: 1) young male runners and skaters; 2) active and hard-pressed women of middle age and over. 4. In male runners and skaters the fracture usually occurs through slender, mainly cortical bone, two inches or more above the tip of the lateral malleolus; in middle-aged women the fracture is usually distal to the interosseous ligament through thicker, mainly cancellous bone, one and a half inches from the tip of the lateral malleolus. 5. The most convenient name for both groups of fractures in the lowest third is low fatigue fracture of the fibula. 6. A review of the literature of fatigue fracture of the uppermost third of the fibula shows that it is very often precipitated by jumping. The most convenient name for it is high fatigue fracture of the fibula. 7. Like all clinical classifications this distinction between low and high fractures has exceptions (a low fracture of one fibula in a runner was followed later by a high fracture of the other; most military fractures were high, but a few may have occurred at other levels). 8. Fatigue fracture of the fibula, high or low, may be bilateral. 9. A fracture similarly situated to the high fatigue fracture of the fibula has been frequent in parachute schools. It is a speculative possibility that military and parachutist fractures of the upper third of the fibula indicate the link between true fatigue fractures (as exemplified by march fractures with minimal trauma often repeated) and purely traumatic fractures (with adequate trauma applied once only)

Introduction. A significant burden of disease exists with respect to critical sized bone defects; outcomes are unpredictable and often poor. There is no absolute agreement on what constitutes a “critically-sized” bone defect however it is widely considered as one that would not heal spontaneously despite surgical stabilisation, thus requiring re-operation. The aetiology of such defects is varied. High-energy trauma with soft tissue loss and periosteal stripping, bone infection and tumour resection all require extensive debridement and the critical-sized defects generated require careful consideration and strategic management. Current management practice of these defects lacks consensus. Existing literature tells us that tibial defects 25mm or great have a poor natural history; however, there is no universally agreed management strategy and there remains a significant evidence gap. Drawing its origins from musculoskeletal oncology, the Capanna technique describes a hybrid mode of reconstruction. Mass allograft is combined with a vascularised fibula autograft, allowing the patient to benefit from the favourable characteristics of two popular reconstruction techniques. Allograft confers initial mechanical stability with autograft contributing osteogenic, inductive and conductive capacity to encourage union. Secondarily its inherent vascularity affords the construct the ability to withstand deleterious effects of stressors such as infection that may threaten union. The strengths of this hybrid construct we believe can be used within the context of critical-sized bone defects within tibial trauma to the same success as seen within tumour reconstruction. Methodology. Utilising the Capanna technique in trauma requires modification to the original procedure. In tumour surgery pre-operative cross-sectional imaging is a pre-requisite. This allows surgeons to assess margins, plan resections and order allograft to match the defect. In trauma this is not possible. We therefore propose a two-stage approach to address critical-sized tibial defects in open fractures. After initial debridement, external fixation and soft tissue management via a combined orthoplastics approach, CT imaging is performed to assess the defect geometry, with a polymethylmethacrylate (PMMA) spacer placed at index procedure to maintain soft tissue tension, alignment and deliver local antibiotics. Once comfortable that no further debridement is required and the risk of infection is appropriate then 3D printing technology can be used to mill custom jigs. Appropriate tibial allograft is ordered based on CT measurements. A pedicled fibula graft is raised through a lateral approach. The peroneal vessels are mobilised to the tibioperoneal trunk and passed medially into the bone void. The cadaveric bone is prepared using the custom jig on the back table and posterolateral troughs made to allow insertion of the fibula, permitting some hypertrophic expansion. A separate medial incision allows attachment of the custom jig to host tibia allowing for reciprocal cuts to match the allograft. The fibula is implanted into the allograft, ensuring nil tension on the pedicle and, after docking the graft, the hybrid construct is secured with multi-planar locking plates to provide rotational stability. The medial window allows plate placement safely away from the vascular pedicle. Results. We present a 50-year-old healthy male with a Gustilo & Anderson 3B proximal tibial fracture, open posteromedially with associated shear fragment, treated using the Capanna technique. Presenting following a fall climbing additional injuries included a closed ipsilateral calcaneal and medial malleolar fracture, both treated operatively. Our patient underwent reconstruction of his tibia with the above staged technique. Two debridements were carried out due to a 48-hour delay in presentation due to remote geographical location of recovery. Debridements were carried out in accordance with BOAST guidelines; a spanning knee external fixator applied and a small area of skin loss on the proximal medial calf reconstructed with a split thickness skin graft. A revision cement spacer was inserted into the metaphyseal defect measuring 84mm. At definitive surgery the external fixator was removed and graft fixation was extended to include the intra-articular fragments. No intra-operative complications were encountered during surgeries. The patient returned to theatre on day 13 with a medial sided haematoma. 20ml of haemoserous fluid was evacuated, a DAIR procedure performed and antibiotic-loaded bioceramics applied locally. Samples grew Staphylococcus aureus and antibiotic treatment was rationalised to Co-Trimoxazole 960mg BD and Rifampicin 450mg BD. The patient has completed a six-week course of Rifampicin and continues on suppressive Co-Trimoxazole monotherapy until planned metalwork removal. There is no evidence of ongoing active infection and radiological evidence of early union. The patient is independently walking four miles to the gym daily and we believe, thus far, despite accepted complications, we have demonstrated a relative early success. Conclusions. A variety of techniques exist for the management of critical-sized bone defects within the tibia. All of these come with a variety of drawbacks and limitations. Whilst acceptance of a limb length discrepancy is one option, intercalary defects of greater than 5 to 7cm typically require reconstruction. In patients in whom fine wire fixators and distraction osteogenesis are deemed inappropriate, or are unwilling to tolerate the frequent re-operations and potential donor site morbidity of the Masqualet technique, the Capanna technique offers a novel solution. Through using tibial allograft to address the size mismatch between vascularised fibula and tibia, the possible complication of fatigue fracture of an isolated fibula autograft is potentially avoidable in patients who have high functional demands. The Capanna technique has demonstrated satisfactory results within tumour reconstruction. Papers report that by combining the structural strength of allograft with the osteoconductive and osteoinductive properties of a vascularised autograft that limb salvage rates of greater than 80% and union rates of greater than 90% are achievable. If these results can indeed be replicated in the management of critical-sized bone defects in tibial trauma we potentially have a treatment strategy that can excel over the more widely practiced current techniques

Aim: To calculate the incidence and timing of metal failure in endoprostheses used for bone tumour reconstructions and to analyse the mode of failure. Methods: A retrospective analysis was performed on 468 endoprostheses with an average follow-up of 50 months. The explanted prostheses were studied to determine the mode of failure and the design and material features that might have contributed to the failure. Results: There were 18 mechanical failures of metal. A total of 19 cases were revised for loosening one of which was noted to have a metal fracture pending at the time of the revision. There were three cases of failure of the coupling between components of modular systems. All of the remaining cases (16) were in the lower limb and these failed by fracture of the metal. The fractures occurred at an average of 92 months. The majority of the fractures that were seen were simple fatigue fractures but in three cases other types of failure were also involved. There were no fatigue fractures in forged cobalt chrome components. Fatigue fracture of the cast cobalt chrome implants could always be attributed to a local stress riser or a local area of high stress due to features of the design. Fatigue fractures of titanium implants were often related to notching. Discussion: The large skeletal defects left by resection of bone tumours can often be reconstructed with endo-prostheses. The mechanical demands on these implants are great resulting in a relatively high incidence of metal failure. Improvements in design and materials can minimise these failures

Introduction. Lumbar spondylolysis is a fatigue fracture of the pars interarticularis and correlates with Spina Bifida Oculta (SBO) in 67%. Hpothesis. Load is normally transferred across the arch in axial rotation. Bifid arch results in increased strain across the isthmus of the loaded inferior articular process. Aim of investigation. Finite element (FE) analysis of altered load transfer in combined axial rotation and anteroposterior shear in SBO potentially predisposing to fatigue fracture of the pars interarticularis. Methods. FE models of natural and SBO (L5-S1) including ligaments were axially load to 1kN and an axial rotation of 3° applied. Bilateral stresses and strains on intact and SBO lateral inferior lines of the L5 isthmus were assessed and compared. Results. Under 1000N axial load: Maximum von Mises stress observed on left and right lateral inferior lines of L5 isthmus were 0.13 and 0.24 MPa, with maximum equivalent strain values of 1.56 and 2.91 (strain, for natural spine and SBO, respectively. Combined with 3° axial rotation (rotation of spinal processes toward right lateral side): Left lateral L5 isthmus stresses increased to 0.49 and 0.77 MPa for natural spine and SBO, respectively. Right lateral L5 isthmus values increased to 0.67 and 0.95 MPa for natural spine and SBO, respectively. The percentage increase in SBO strains compared to the natural spine on the L5 isthmus were +57.9 and +40.2%. Conclusion. Significant load transfer occurs through the vertebral arch in axial rotation. In SBO this load transfer is lost and mechanical demand on the isthmus is significantly increased. Strain increases across the L5 isthmus in axial rotation by +40.2% to +57.9% compared to normal and may predispose to fatigue fracture

Ti-6Al-4V is the most common alloy used for orthopaedic implants. Its popularity is due to low density, superior corrosion resistance, good osseointegration and lower elastic modulus when compared to other commonly used alloys such as CoCrMo and stainless steel. In fact, the use of Ti64 has even further increased lately since recent controversy around adverse local tissue reactions and implant failure related to taper corrosion of CoCrMo alloy. However, implants made from Ti64 can fail in some cases due to fatigue fracture, sometimes related to oxide induced stress corrosion cracking or hydrogen embrittlement, or preferential corrosion of the beta phase. Studies performed with Ti-6Al-4V do often not consider that the alloy itself may have a range of characteristics that can vary and could significantly impact the implant properties. These variations are related to the material microstructure which depends not only on chemical composition, but also the manufacturing process and subsequent heat treatments. Different microstructures can occur in implants made form wrought alloys, cast alloys, and more recently, additive manufactured (AM) alloys. Implant alloy microstructure drives mechanical and electrochemical properties. Therefore, this study aims to analyse the microstructure of Ti-6Al-4V alloy of additive manufactured and conventional retrieved orthopaedic implants such as acetabular cups, tibial trays, femoral stem and modular neck by means of electron backscatter diffraction (EBSD). Microstructural features of interest include grains shape and size, phase content and distribution, preferred grain orientation (texture), alloying elements distribution (homogenization) and presence of impurities. Additionally, we demonstrate the direct impact of different microstructural features on hardness. We analysed 17 conventional devices from 6 different manufacturers, 3 additive manufactured devices from 2 different manufactures and 1 control alloy (bar stock). The preliminary results showed that even though all implants have the same chemical composition, their microstructural characteristics vary broadly. Ti64 microstructure of conventional alloys could be categorized in 3 groups: equiaxed grains alloys (Fine and Coarse), bimodal alloys and dendritic alloys. The additive manufactured implants were classified in an additional group on its own which consists of a needle-like microstructures - similar to Widmanstätten patterns, Fig. 1, with a network of β phase along α phase grains. Furthermore, AM alloys exhibited residual grain boundaries from the original β grains from the early stage of the solidification process, Fig. 2. These characteristics may have implication on the fatigue and corrosion behaviour. In addition, it we observed inhomogeneous alloying element distribution in some cases, Fig. 3, especially for the additive manufactured alloys, which also may have consequences on corrosion behaviour. Finally, the hardness testing revealed that the implants with large grain size, such as AM alloys, exhibit low hardness values, as expected, but also the amount of beta phase correlated positively with lower hardness. Grain aspect ratio and beta phase grain size correlated positively with higher hardness. In summary, we found that common Ti64 implants can exhibit a broad variety of different alloy microstructures and the advent of AM alloys introduces an entirely new category. It is imperative to determine the ideal microstructure for specific applications

1. The femoral head has been examined in specimens taken from cadavers, patients suffering subcapital fracture of the femoral neck and patients undergoing total replacement arthroplasty for osteoarthrosis and rheumatoid arthritis. 2. Lesions have been seen, some of which appear to be uniting fatigue fractures of individual trabeculae. 3. It is suggested that excessive cyclical loading, sometimes leading to fatigue fractures, may represent a fundamental pathological process of general importance in the evolution of certain skeletal and articular diseases

We evaluated 31 patients who were treated with a non-vascularised fibular graft after resection of primary musculoskeletal tumours, with a median follow-up of 5.6 years (3 to 26.7 years). Primary union was achieved in 89% (41 of 46) of the grafts in a median period of 24 weeks. All 25 grafts in 18 patients without additional chemotheraphy and/or radiotherapy achieved primary union, compared with 16 of the 21 grafts (76%; 13 patients) with additional therapy (p = 0.017). Radiographs showed an increase in diameter in 70% (59) of the grafts. There were seven fatigue fractures in six patients, but only two needed treatment. Non-vascularised fibular transfer is a simpler, less expensive and a shorter procedure than the use of vascularised grafts and allows remodelling of the fibula at the donor site. It is a biological reconstruction with good long-term results, and a relatively low donor site complication rate of 16%

Aims: The knee is the commonest articular location in osteosarcoma (OS). We study the complications in limb salvage due to OS in knee reconstructions. Methods: In our series of 107 OS for the period 1983–1998, limb salvage procedure was possible in 78 cases and the amputation was necessary in 29 patients. The Knee reconstruction includes 62 cases (39 due to femur OS and 23 due to tibia OS). All cases were treated with preoperative and postoperative chemotherapy. The average follow-up was 87.4 months with a range of 55 to 183 months. Results: Complications in re-constructions due to femur OS:. – Local recurrence 2/39 (5.13%). – Infection 2/39 (5.13%). – Fatigue fracture (7.6%) Complications in tibia re-constructions:. – Local recurrences 3/23 (13%). – Infection 5/23 (21.7%). Patellar tendon tear off 2/23 (8.7%). Fatigue fracture 1/23 (4.35%). Conclusions: The rate of complications in tibia is higher than in femur. The infections in tibia limb salvage are related to skin coverage. The local recurrence in tibia is related to anatomical problems to achieve wide resections

Many pedicle screw instrumentation systems are currently available to the spine surgeon. Each system has its unique characteristics. It is important for the surgeon to understand the differences in these pedicle screw systems. 1. Following the introduction of a new spinal instrumentation set to our clinical practice we encountered two cases of pedicle screw breakage. We thus decided to investigate the mechanism of this screw failure (screw A) in these particular cases and to compare the biomechanical properties, through independent analysis, of a variety of pedicle screws from different manufacturers. Samples of the broken pedicle screws were retrieved at surgery. Surface analysis of the fracture area using the electron microscope, demonstrated features consistent with fatigue fracture. Pedicle screws of comparable size from a variety of manufacturers were gathered for independent analysis. Shadowgraph analysis was performed of each screw allowing multiple measurements to be taken of the screw’s geometry. Using this data stress concentration factors were determined demonstrating screw A to have larger values than all the other screws ranging from 2 – 3.6 times the nominal stress. The smaller teeth of screw A, spaced further apart than in the other screws, means that the large proportion of the load which would be carried by the threads is distributed over a smaller area resulting in higher stresses in the threads. The sharp corner at the root of the thread, acting as a stress concentrator, would become the focal point of these high stresses, and magnify them by 2 to 3.6 times. These increased stresses most likely account for an increased susceptibility to fatigue fracture seen in screw A. In conclusion it is important to be careful with the introduction and use of new pedicle screw materials and designs, that all the standard biomechanical testing has been performed to a satisfactory standard. Knowing the physical characteristics of the available pedicle screw instrumentation systems may allow the choice of pedicle screw best suited for a given clinical situation

Cement fixation of the glenoid implants in total shoulder arthroplasty has been the norm since the procedure has existed. Yet, an unacceptably high rate of lucent lines, representing prosthetic loosening, and a high rate of resultant failure of fixation of these implants continues to be the single most common cause for revision surgery in total shoulder arthroplasty. Dissatisfaction with a higher than acceptable rate of lucent lines, cement fixation of the glenoid component has led us to evaluate and employ an implant anchored into the glenoid vault with a woven tantalum (trabecular metal) fixation stem. We have employed this implant in patients with healthy bone stock with a minimum 2-year follow-up in well over 100 cases with only one revision performed in a first generation implant due to fatigue fracture. No cases have demonstrated lucency or loosening. The procedure does require meticulous attention to detail to ensure precise surface and glenoid vault preparation providing complete intraosseous seating of the trabecular metal anchor and flush apposition and support of the polyethylene surface upon the face of the glenoid. This process has reduced surgical preparation time as well as time required for cement setting by an average of 20 minutes per case

Aims

Pelvic discontinuity is a rare but increasingly common complication of total hip arthroplasty (THA). This single-centre study evaluated the performance of custom-made triflange acetabular components in acetabular reconstruction with pelvic discontinuity by determining: 1) revision and overall implant survival rates; 2) discontinuity healing rate; and 3) Harris Hip Score (HHS).

Modular femoral stems for total hip arthroplasty (THA) were introduced to allow additional options for surgeons in controlling leg lengths, offset, and implant stability. This option is widely used in Region Emilia Romagna, Italy, where the study was conducted, having a modular neck stem nearly 35% of primary THA in 2013. Great majority of modular neck is made of Titanium alloy. The study was designed as a retrospective descriptive case series of 67 hips in patients who underwent revision of a THA. All had a Titanium modular neck. In 44 cases revision was due to breakage of the neck, in the remaining 23 it was due to different reasons unrelated to modular neck such as bone fracture, breakage of a ceramic component, cup loosening. Mean follow up was 3.5 yrs. For all patients excised capsule and surrounding tissue were graded for presence of necrosis, inflammatory exudate, lymphocytes, and wear particles using light microscopy of routine paraffin sections stained with hematoxylin and eosin. The retrieved modular neck-body and head-neck junctions were examined for evidence of fretting and corrosion. For some patient dosage of circulating Titanium was obtained. Approval was obtained from institutional review board. It resulted that a variable amount of wear was observed in the first group of patients, with no evidence of lymphocytic reaction, but with variable notes of necrosis. Broken necks showed different patterns of damage, with different degree of corrosion, beside the fatigue fracture. In the second group wear was less evident or absent and negativity of lymphocyte reaction was substantially confirmed. Circulating Titanium ions were one order of magnitude higher in first group (mean 35 micrograms /litre). It can be concluded that fracture of Titanium modular necks occurs progressively, wear does not induce lymphocytic reaction and circulating ions increase. Level of Evidence. III retrospective, comparative study. Acknowledgments. The research was funded by Ministry of Health, grant ‘Early diagnosis of pending failure…’RF 20091472961