Introduction. High-flexion knee implants have been developed to accommodate a large range of motion (ROM > 120°) after total knee arthroplasty (TKA). In a recent follow-up study, Han et al. [1] reported a disturbingly high incidence of femoral loosening for high-flexion TKA. The femoral component loosened particularly at the implant-cement interface. Highly flexed knee implants may be more sensitive to femoral loosening as the knee load is high during deep knee flexion [2], which may result in increased tensile and/or shear stresses at the femoral implant fixation. The objective of this study was to analyse the load-transfer mechanism at the femoral implant-cement interface during deep knee flexion (ROM = 155°). For this purpose, a three-dimensional finite element (FE) knee model was developed including high-flexion TKA components. Zero-thickness cohesive elements were used to model the femoral implant-cement interface. The research questions addressed in this study were whether high-flexion leads to an increased tensile and/or shear stress at the femoral implant-cement interface and whether this would lead to an increased risk of femoral loosening. Materials & methods. The FE knee model utilized in this study has been described previously [3] and consisted of a proximal tibia and fibula, TKA components, a quadriceps and patella tendon and a non-resurfaced patella. For use in this study, the distal femur was integrated in the FE model including cohesive interface elements and a 1 mm bone cement layer. High-flexion TKA components of the posterior-stabilised PFC Sigma RP-F (DePuy, J&J, USA) were incorporated in the FE knee model following the surgical procedure provided by the manufacturer. A full weight-bearing squatting cycle was simulated (ROM = 50°-155°). The interface stresses calculated by the FE knee model were decomposed into tension, compression and shear components. The strength of the femoral implant-cement interface was determined experimentally using interface specimens to predict whether a local interface stress-state calculated by the FE knee model would lead to interface debonding. Results. During deep knee flexion, tensile stress concentrations were found at the femoral implant-cement interface particularly beneath the anterior flange. Shear stress concentrations were observed at the interface beneath the anterior flange and the posterior femoral condyles. The peak tensile interface stress increased from 1.6 MPa at 120° of flexion to 5.5 MPa during deep knee flexion at the interface beneath the anterior flange. The peak shear stress was even higher at this interface location and increased from 4.1 MPa at 120° of flexion to 11.0 MPa at maximal flexion (155°). Based on the interface strength experiments, 5.8% of the interface beneath the anterior flange was predicted to debond at 120° of flexion, which increased to 10.8% during deep knee flexion. Discussion. Obviously, the FE knee model utilized in this study contains limitations which may have affected the interface stresses calculated. However, the results presented here clearly demonstrate increasing tensile and shear stresses in substantial parts of the femoral implant-cement beneath the anterior flange during deep knee flexion. Based on the interface strength experiments the anterior interfacial stress-state calculated by the FE knee model leads to local interface debonding during deep knee flexion, which increases the risk of femoral loosening. Proper anterior fixation of the femoral component is essential to reduce the risk of femoral loosening for high-flexion TKA

In primary total hip replacements there are numerous options available for providing hip stability in difficult situations (i.e. Down's syndrome, Parkinson's disease). We have considered constrained liners in some of these cases. However, in the revision situation in general and in revision for recurrent dislocation situation specifically it is important to have all options available including tripolar constrained liners in order to optimise the potential for hip stability as well as function of the arthroplasty. Even with the newer options available dislocation rates of higher than 10–15% have been reported following revision surgery at institutions where high volumes of revision surgery are performed. Because of the deficient abductors, other soft tissue laxity and the requirement for large diameter cups revision cases will always have more potential for dislocation. In these situations in the lower demand patient, constraint has provided excellent success in terms of preventing dislocation and maintaining implant construct fixation to bone at intermediate- term follow-up. Hence in these situations tripolar constrained liners remains the option we utilise. We are also confident in using this device in cases with instability or laxity where there is a secure well- positioned acetabular shell. We cement a dual mobility constrained liner in these situations using the technique described below. Present indication for tripolar constrained liners: low demand patient, large outer diameter cups, instability with well-fixed shells that are adequately positioned, abductor muscle deficiency or soft tissue laxity, multiple operations for instability. Technique of cementing liner into shell: score acetabular shell if no holes, score liner in spider web configuration, all one or two millimeters of cement mantle. Results. Constrained Dual Mobility Liner. For Dislocation: 56 Hips, 10 yr average f/u, 7% failure of device, 5% femoral loosening, 4% acetabular loosening. For Difficult Revisions:101 hips, 10 yr average f/u, 6% failure of device, 4% femoral loosening, 4% acetabular loosening. Cementing Liner into Shell: 31 hips, 3.6 yr average f/u (2–10 years), 2 of 31 failures

Introduction & aims. Apparently well-orientated total hip replacements (THR) can still fail due to functional component malalignment. Previously defined “safe zones” are not appropriate for all patients as they do not consider an individual's spinopelvic mobility. The Optimized Positioning System, OPS. TM. (Corin, UK), comprises preoperative planning based on a patient-specific dynamic analysis, and patient-specific instrumentation for delivery of the target component alignment. The aim of this study was to determine the early revision rate from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) for THRs implanted using OPS. TM. . Method. Between January 4. th. 2016 and December 20. st. 2017, a consecutive series of 841 OPS. TM. cementless total hip replacements were implanted using a Trinity acetabular cup (Corin, UK) with either a TriFit TS stem (98%) or a non-collared MetaFix stem (2%). 502 (59%) procedures were performed through a posterior approach, and 355 (41%) using the direct superior approach. Mean age was 64 (range; 27 to 92) and 51% were female. At a mean follow-up of 15 months (range; 3 to 27), the complete list of 857 patients was sent to the AOANJRR for analysis. Results. There were 5 revisions: . a periprosthetic femoral fracture at 1-month post-op in a 70F. a ceramic head fracture at 12-months post-op in a 59M. a femoral stem loosening at 7-months post-op in a 58M. a femoral stem loosening at 16-months post-op in a 64M. an anterior dislocation in a 53M, that was revised 9 days after the primary procedure. CT analysis, prior to revision surgery, revealed acetabular cup orientation of 46°/31° (inclination/anteversion) and femoral stem anteversion of 38°. Conclusions. These preliminary findings suggest the OPS. TM. dynamic planning and delivery system provides good early results, with a low rate of revision for dislocation. Limitations of the study will be discussed

In the revision situation in general and for recurrent dislocation specifically, it is important to have all options available including tripolar constrained liners in order to optimise the potential for hip stability as well as function. Even with the newer options available, dislocation rates of higher than 5% have been reported in the first two years following revision surgery at institutions where high volumes of revision surgery are performed (Wera et al). Because of the deficient abductors, other soft tissue laxity and the requirement for large diameter cups, revision cases will always have more potential for dislocation. In these situations, in the lower demand patient, tripolar constrained liners provided excellent success in terms of preventing dislocation and maintaining implant construct fixation to bone at intermediate term follow-up. Hence in these situations, tripolar with constraint remains the option we utilise in many cases. We are also confident in using this device in cases with instability or laxity where there is a secure well positioned acetabular shell. We cement a tripolar constrained liner in these situations using the technique described below. Present indication for tripolar constrained liners: low demand patient, abductor muscle deficiency or soft tissue laxity, large outer diameter cups, multiple operations for instability, instability with well-fixed shells that are adequately positioned. Technique of cementing liner into shell: score acetabular shell if no holes, score liner in spider web configuration, all one or two millimeters of cement mantle. Results: Constrained Tripolar Liner - For Dislocation: 56 Hips; 10 year average f/u; 7% failure of device, 5% femoral loosening, 4% acetabular loosening. Constrained Tripolar Liner - For Difficult Revisions: 101 hips; 10 year average f/u; 6% failure of device, 4% femoral loosening, 4% acetabular loosening. Cementing Liner into Shell: 31 hips; 3.6 year average f/u (2–10 years); 2 of 31 failures. We, like others, are trying to define cases where dual mobility will be as successful or more successful than tripolar constrained liners

In primary total hip replacements there are numerous options available for providing hip stability in difficult situations (i.e. Down's syndrome, Parkinson's disease). However, in the revision situation in general and in revision for recurrent dislocation specifically, it is important to have all options available including dual mobility constrained liners in order to optimise the potential for hip stability as well as function of the arthroplasty. Even with the newer options, available dislocation rates of higher than 5% have been reported in the first two years following revision surgery at institutions where high volumes of revision surgery are performed. Because of the deficient abductors, other soft tissue laxity and the requirement for large diameter cups, revision cases will always have more potential for dislocation. In these situations in the lower demand patient and where, a complex acetabular reconstruction that requires time for ingrowth before optimal implant bone stability to occur isn't present, dual mobility with constraint has provided excellent success in terms of preventing dislocation and maintaining implant construct fixation to bone at intermediate term follow-up. Hence in these situations dual mobility with constraint remains the option we utilise. We are also confident in using this device in cases with instability or laxity where there is a secure well-positioned acetabular shell. We cement a dual mobility constrained liner in these situations using the technique described below. Present indication for dual mobility constrained liners: low demand patient, large outer diameter cups, instability with well-fixed shells that are adequately positioned, abductor muscle deficiency or soft tissue laxity, multiple operations for instability. Technique of cementing liner into shell: score acetabular shell if no holes, score liner in spider web configuration, all one or two millimeters of cement mantle. Results: Constrained Dual Mobility Liner – For Dislocation: 56 Hips, 10 year average follow-up, 7% failure of device, 5% femoral loosening, 4% acetabular loosening. For Difficult Revisions: 101 hips, 10 year average follow-up, 6% failure of device, 4% femoral loosening, 4% acetabular loosening. Cementing Liner into Shell: 31 hips, 3.6 year average follow-up (2–10 years), 2 of 31 failures

Introduction. Most metal-on-metal hip resurfacing implants currently being used worldwide utilize bone ingrowth fixation on the acetabular side, but cement fixation remains the standard method of fixation on the femoral side. Our hypothesis is that bone ingrowth fixation of a fully porous-coated component is superior to cement fixation of the femoral hip resurfacing component. Methods. From March 2007 to Jan 2009, 429 consecutive metal-on-metal hip resurfacing arthroplasties were performed by a single surgeon in 396 unselected patients using Biomet uncemented femoral and acetabular components. All of these were at least 5-years postop. Three patients died with causes unrelated to their hip arthroplasty. The three most common primary diagnoses were osteoarthritis in 318 (74%) cases, dysplasia in 66 (15%) hips, and osteonecrosis in 19 (4%) hips. The average size of the femoral component was 50 ± 4 cm. All pre-operative, intra-operative, and post-operative data were prospectively collected and entered into our database for review. All patients are allowed unrestricted activity including impact sports after 6 months. Results. Metal ion test results were available for 78% of patients. There were 14 (3.2%) failures identified at the time of this study. There were six (1.4%) early femoral failures (4 femoral neck fractures, 2 head collapses prior to 2 years), four loose acetabular components (one failed at 2 months postoperatively; three after 2 years), two (0.5%) adverse wear related failures (AWRF; metal ion levels ≥10 ug/L, AIA> 50. 0. , metalosis), one intertrochanteric fracture; and one failure due to subluxation. There were no cases of failure of femoral ingrowth or late femoral loosening. For the non-failed group, the average post-operative HHS score was 97±9 at their latest follow-up; the average UCLA Activity Score was 7±2. Survivorship was 96.7% at 5 years (all failures). Femoral survivorship was 98.4%. The AWRF rate was 0.5% at 5 years. No femoral failures occurred after one year postop up to 7 years. Conclusions. Bone ingrowth fixation with a fully porous femoral component in hip resurfacing remains highly durable beyond 5 years. Femoral ingrowth is more reliable than acetabular ingrowth. No cases of femoral loosening have been encountered up to 7 years post implantation. AWRF is rare (0.5% at 5 years) and is caused by acetabular component malposition

In primary total hip replacements there are numerous options available for providing hip stability in difficult situations i.e. Down's syndrome, Parkinson's disease. However, in the revision situation, in general, and in revision for recurrent dislocation situations specifically, it is important to have all options available including dual mobility constrained liners in order to optimise the potential for hip stability as well as function of the arthroplasty. Even with the newer options available dislocation rates of higher than 5% have been reported in the first two years following revision surgery at institutions where high volumes of revision surgery are performed [Della Valle, Sporer, Paprosky unpublished data]. Because of the deficient abductors, other soft tissue laxity and the requirement for large diameter cups, revision cases will always have more potential for dislocation. In these situations in the lower demand patient and where, a complex acetabular reconstruction that requires time for ingrowth before optimal implant bone stability to occur isn't present, dual mobility with constraint has provided excellent success in terms of preventing dislocation and maintaining implant construct fixation to bone at intermediate term follow-up. Hence in these situations dual mobility with constraint remains the option we utilise. We are also confident in using this device in cases with instability or laxity where there is a secure well-positioned acetabular shell. We cement a dual mobility constrained liner in these situations using the technique described below. Present indication for dual mobility constrained liners: low demand patient, abductor muscle deficiency or soft tissue laxity, large outer diameter cups, multiple operations for instability, and instability with well-fixed shells that are adequately positioned. Technique of cementing liner into shell: score acetabular shell if no holes; score liner in spider web configuration; all one or two millimeters of cement mantle. Results. Constrained Dual Mobility Liner. For Dislocation: 56 Hips 10 yr average f/u, 7% failure of device, 5% femoral loosening, 4% acetabular loosening. For Difficult Revisions: 101 hips 10 yr average f/u, 6% failure of device, 4% femoral loosening, 4% acetabular loosening. Cementing Liner into Shell: 31 hips 3.6 yr average f/u (2–10 years), 2 of 31 failures

Anterior surgical approaches for total hip arthroplasty (THA) have increased popularity due to expected faster recovery and less pain. However, the direct anterior approach (Heuter approach which has been popularised by Matta) has been associated with a higher rate of early revisions than other approaches due to femoral component loosening and fractures. It is also noted to have a long learning curve and other unique complications like anterior femoral cutaneous and femoral nerve injuries. Most surgeons performing this approach will require the use of an expensive special operating table. An alternative to the direct anterior approach is the anterior-based muscle-sparing approach. It is also known as the modified Watson-Jones approach, anterolateral muscle-sparing approach, minimally invasive anterolateral approach and the Röttinger approach. With this technique, the hip joint is approached through the muscle interval between the tensor fascia lata and the gluteal muscles, as opposed to the direct anterior approach which is between the sartorius and rectus femoris and the tensor fascia lata. This approach places the femoral nerve at less risk for injury. I perform this technique in the lateral decubitus position, but it can also be performed in the supine position. An inexpensive home-made laminated L-shaped board is clamped on end of table allowing the ipsilateral leg to extend, adduct, and externally rotate during the femoral preparation. This approach for THA has been reported to produce excellent results. One study reports a complication rate of 0.6% femoral fracture rate and 0.4% revision rate for femoral stem loosening. In a prospective randomised trial looking at the learning curve with new approach, the anterior-based muscle-sparing anterior approach had lower complications than a direct anterior approach. The complications and mean operative time with this approach are reported to be no different than a direct lateral approach. Since this surgical approach is not through an internervous interval, a concern is that this may result in a permanent functional defect as result of injury to the superior gluteal nerve. At a median follow-up of 9.3 months, a MRI study showed 42% of patients with this approach had fat replacement of the tensor fascia lata, which is thought to be irreversible. The clinical significance remains unclear, and inconsequential in my experience. A comparison MRI study showed that there was more damage and atrophy to the gluteus medius muscle with a direct lateral approach at 3 and 12 months. My anecdotal experience is that there is faster recovery and less early pain with this approach. A study of the first 57 patients I performed showed significantly less pain and faster recovery in the first six weeks in patients performed with the anterior-based muscle-sparing approach when compared to a matched cohort of THA patients performed with a direct lateral approach. From 2004 to 2017, I have performed 1308 total hip replacements with the anterior-based muscle sparing approach. Alternatively, I will use the direct lateral approach for patients with stiff hips with significant flexion and/or external rotation contractures where I anticipate difficulty with femoral exposure, osteoporotic femurs due to increased risk of intraoperative trochanteric fractures, previously operated hips with scarring or retained hardware, and Crowe III-IV dysplastic hips when there may be a need for a femoral shortening or derotational osteotomy. Complications have been very infrequent. This approach is a viable alternative to the direct anterior approach for patients desiring a fast recovery. The anterior-based muscle-sparing approach is the approach that I currently use for all outpatient total hip surgeries

Total knee arthroplasty has been the main treatment method among advanced osteoarthritis (OA) patients. The main post-operative evaluation considers the level of pain, stability and range of motion (ROM). The knee flexion level is one of the most important categories in the total knee arthroplasty patient's satisfaction in Asian countries due to consistent habits of floor-sitting, squating, kneeling and cross legged sitting. In this study, we discovered that the posterior capsular release enabled the further flexion angles by 14 degrees compared to the average ROM without posterior release group. Our objective was to increase the ROM using the conventional total knee arthroplasty by the posterior capsular release. Posterior capsular release is being used in order to manage the flexion contraction. Although the high flexion method extends the contact area during flexion by extending the posterior condyle by 2mm, the main problem has been the early femoral loosening. We searched for the method to get the deep knee flexion with the conventional knee prosthesis. 122 OA patients with less than preoperative 130 flexion that underwent conventional TKAs using Nexgen from January, 2014 to September, 2016 were reviewed. Posterior femoral osteophytes were removed as much as possible, but 74 cases were performed posterior capsular release, while 48 cases were not performed. After checking postoperative ROM after 6 months of operation, we compared 74 knees with a posterior capsular release and 48 knees without posterior capsular release. As a result, the average ROM in the posterior capsular release group was 132 degrees, but the average ROM without posterior release group is 118 degrees. No postoperative hyperextension was found when the adequate size of polyethylene (PE) thickness was utilized. Hence, the conventional TKA with a posterior capsular release showed satisfactory clinical outcomes in the deep knee flexion of Asians

BACKGROUND. The most common salvage of a failed metal-on-metal hip resurfacing is to remove both the femoral and acetabular resurfacing components and perform a total hip replacement. The other choices are to perform an acetabular or femoral only revision. A one or two piece acetabular component or a polyethylene bipolar femoral component that matches the retained metal resurfacing acetabular component is used. The considerations in favor of performing a one component resurfacing revision are maintaining the natural femoral head size, limiting the surgical effort for the patient and surgeon, and bone conservation. There are often favorable cost considerations with single component revision surgery. The reasons for femoral component revision are femoral neck fracture, femoral component loosening and an adverse reaction to metal wear debris. Performing a femoral component only revision requires a well fixed and well oriented acetabular component. Acetabular revision is most often performed for an adverse reaction to metal wear debris or loosening. METHODS. 81 acetabular revisions and 46 femoral revisions were evaluated 4 to 14 years after surgery. 83% of patients had their initial surgery at outside institutions. The mean age was 46 and 65% of patients were women. A two piece titanium backed polyethylene component was used in 44 patients and a one or two piece metal component was used in 37. A dual mobility femoral prosthesis mated to a retained metal acetabular component was used for the femoral revisions and no conversions to a metal-on-metal total hip replacement were performed. We selected polyethylene acetabular components for patients with adverse reactions to metal wear debris if their femoral component was less than 48 mm or if there was no matching metal acetabular component available for their femoral component. We used dual mobility components for femoral loosening, femoral neck fractures and adverse reactions to metal wear debris in patients with well-fixed and well oriented metal acetabular components. Dual mobility components were also used if there are any concerns about the femoral component or in some older patients. We performed one component revisions rather than conversion to total hip replacement on 88% of patients presenting with failed resurfacing prostheses. RESULTS. There were no failures with polyethylene acetabular components. There were two failures due to ongoing adverse metal reactions in patients receiving metal revision acetabular components. There was one failure with a dual mobility prosthesis due to accelerated polyethylene wear from undetected edge loading on a retained worn metal acetabular component. There were two infections and one patient with continued pain. There were no dislocations. The average Harris Hip Score was 94. The UCLA activity score was 6 or greater for all but 4 patients. There were 6 revisions to total hip replacement. The Kaplan-Meier survivorship was 94%. 95% of patients rated their outcome as excellent or good. CONCLUSIONS. Failed metal-on-metal hip resurfacing prostheses can be successfully revised without conversion to total hip replacement in most instances. A detailed knowledge of matching prostheses is necessary. Polyethylene prostheses for the acetabular or femoral reconstruction are often needed

Introduction. A few follow-up studies of high flexion total knee arthoplasties report disturbingly high incidences of femoral loosening. Finite element analysis showed a high risk for early loosening at the cement-implant interface at the anterior flange. However, femoral implant fixation is depending on two interfaces: cement-implant interface and the cement-bone interface. Due to the geometry of the distal femur, a part of the cement-bone interface consists of cement-cortical bone interface. The strength of the cement-bone interface is lower than the strength of the cement-implant interface. The research questions addressed in this study were: 1) which interface is more prone to loosening and 2) what is the effect of different surgical preparation techniques on the risk for early loosening. Materials & methods. To achieve data for the cement-(cortical)bone interface strength and the effects of different preparation techniques on interfacial strength, human cadaver interface stress tests were performed for different preparation techniques of the bony surface and the results were implemented in a finite element (FE) model as described before. The FE model consisted of a proximal tibia and fibula, TKA components, a quadriceps and patella tendon and a non-resurfaced patella. For use in this study, the distal femur was integrated in the FE model including cohesive interface elements and a 1 mm bone cement layer. In the model, the cement-bone interface was divided into two areas, representing cortical and cancellous bone. The posterior-stabilised PFC Sigma RP-F (DePuy, J&J, USA) was incorporated in the FE knee model following the surgical procedure provided by the manufacturer. A full weight-bearing squatting cycle was simulated (ROM = 50°-155°). The interface failure index was calculated. Results. Overall, the highest stresses were found at the proximo-medial part beneath the anterior flange of the femoral component. Highest shear stresses were found at the cement-implant interface (peak shear stress of 3.33 MPa at 150° of flexion). Highest tensile stresses were found at the cement-cortical bone interface (peak tensile stress of 1.30 MPa at 150° of flexion). The failure index was highest at the cement-bone interface. When the total anterior flange was covering cancellous bone, 0.4% of the cement-bone interface would fail and 0% of the cement-implant interface at 145° of flexion. In the more realistic simulation of cortical bone with periost, almost 31.3% of the complete cement-bone interface would fail even within normal range of motion (<120°). This can be reduced by drilling holes through the cortex to 2.6%. Discussion. Obviously, the FE knee model utilized in this study contains limitations which may have affected the interface stresses calculated. However, the results presented here clearly demonstrate high risk of early loosening at the cement-bone interface. This risk can be reduced by some simple preparation techniques of the cortex behind the anterior flange. Proper anterior fixation of the femoral component, and thus adequate surgical technique, is essential to reduce the risk of femoral loosening for high-flexion TKA

Introduction. Hip Resurfacing Arthroplasty (HRA) has been performed in the United States for over 10 years and is an alternative to standard Total Hip Arthropastly (THA). It is appealing to younger patients with end stage osteoarthritis who seek to maintain active lifestyles. Benefits of HRA versus THR include a larger femoral ball size, potential to return to impact activities, decreased dislocation rates, and restoration of normal hip biomechanics. Patients ≤50 years old are a particularly challenging patient group to treat with THA because of their young age and high activity level, and as such, are well-suited for HRA. However, there are limited reports in the literature about clinical, radiographic and functional outcomes for this patient cohort. We present results of a clinical investigation at our institution for this patient cohort with minimum 5-year follow up, including long term survivorship and outcome scores. Methods. HRA, using the Birmingham Hip Resurfacing (BHR), was performed for 538 procedures between 2006–2009 by a single surgeon at a United States teaching hospital. After Institutional Review Board approval, medical and radiographic study records were retrospectively reviewed. Harris Hip Scores (HHS) were routinely collected. Patients who had not returned for follow-up examination were contacted by telephone for information pertaining to their status and implant, and a modified HHS was also administered. A Kaplan Meier survival curve was constructed to evaluate time to revision. Statistical analysis was performed (SAS version 9.3; SAS Institute, Cary, NC). Results. Of the 538 patients who underwent HRA from 2006–2009, 238 were aged ≤50 years (44%). Five-year follow up data was obtained from 209 of these patients (88%), using medical record documentation, and telephone survey as needed. The mean follow-up for all patients was 6 years (range 5–8 years). A total of 3% (8/238) were revised. Reasons included: (i) femoral loosening in 4, (ii) Iliopsoas impingement in 1, (iii) metallosis/adverse tissue reaction in 1, (iv) femoral neck fracture following motor vehicle accident in 1, and (v) unknown reasons in 1. Of the 238 patients, 55 (23%) were female, 2 (2/55; 3.6%) of whom have since undergone revision surgery for either metallosis/adverse tissue reaction, or unknown reasons. Of the 53 women who retained their BHR at 5-year follow up, the average HHS was 96.5. Of the 238 patients, 183 (77%) were male patients, 6 (6/183; 3.2%) of whom have since undergone revision surgery for femoral component loosening, iliopsoas impingement, or femoral neck fracture sustained in a motor vehicle accident. At 5-year follow-up, 177 male patients retained their implant and had an average Harris Hip Score of 98.8. The overall implant survival was 96.6% at approximately 5 years. Conclusion. In our cohort of patients aged ≤50 treated with BHR [Fig. 1], our results demonstrated 5-year survivorship of 96.6%, with average HHS of 98.8 in males and 96.5 in females. This study demonstrates HRA is a successful alternative to traditional THA in a challenging cohort of younger, active patients

The use of endoprosthesis implants is frequent for tumours involving the proximal third of the femur and not amenable to primary arthroplasty or internal fixation. In this population, these implants are preferentially cemented given poor bone quality associated with systemic diseases and treatments. Loosening is a common complication of these implants that have been linked to poor bone quality, type of implants and importantly cementing technique. Thus, these techniques vary between different surgeons and based mainly on previous experience. One of the most successful cementing techniques in the arthroplasty literature is the French paradox. This technique involves removing the cancellous bone of the proximal femoral metaphysis and selects the largest stem to tightly fit the created cavity delineated by cortical bone. Cementing the implant results in a very thin cement layer that fills the inconsistent gaps between the metal and the bone. To our knowledge, no previous report exists in the literature assessing loosening in proximal femur replacement using the French paradox cementing technique. In this study, we sought to examine (1) rates of loosening in proximal femur replacement, and (2) the oncological outcomes including tumour recurrence and implant related complications. A retrospective study of 42 patients underwent proximal femur replacement between 1990 and 2018 at our institution. Of these, 30 patients met our inclusion criteria. Two independent reviewers have evaluated the preoperative and the most recent postoperative radiographs using the International Society of Limb Salvage (ISOLS) radiographic scoring system and Gruen classification for femoral stem loosening. Additionally, the acetabulum was evaluated for erosion according to the criteria of Baker et al. The mean age of this cohort was 60.5 (19–80), with 60% being males. The primary origin was metastatic in 17 (56.7%) patients, bone sarcoma in 10 (33.3%) patients and soft tissue sarcoma in 3 (10%) patients. Pathological fractures were present in 11 (36.7%) patients. Seven (23.3%) patients had prior intramedullary nailing. Preoperative radiotherapy was used in 8 (26.7%) and postoperative radiotherapy in 17 (56.7%) patients. The mean clinical follow-up was 25.2±26.3 months and the mean radiographical follow-up was 24.8±26 months. The mean ISOLS score for both reviewers was found to be 89±6.5% and 86.5±6.1%, respectively. Additionally, the first reviewer found two patients to be possibly loos (6.7%) compared to one (3.3%) patient for the second reviewer. No components scored as probably or definitely loose and non-required revision for either loosening or metal failure. Furthermore, both reviewers showed no acetabular erosion in 25 (83.3%) and 24 (80%) patients, respectively. On the other hand, the overall rate of complications was 36.6% with 11 complications reported in 30 patients. Local recurrence occurred in five (16.6%) patients. Prosthetic Dislocation was the most frequent complications with eight dislocations in four patients. Despite complications, our results showed no radiographic evidence of stem loosening. Cementing proximal femur prosthesis with a tight canal fit and with a thin cement mantle appears to be a viable option at short and medium term

Purpose. Long-term clinical and radiographic results and survival rates were compared between closed-wedge high tibial osteotomy (HTOs) and fixed-bearing unicompartmental knee arthroplasty (UKA) in patients with similar demographics. Methods. Sixty HTOs and 50 UKAs completed between 1992 and 1998 were retrospectively reviewed. There were no significant differences in preoperative demographics. The mean follow-up period was 10.7 ±5.7 years for HTO and 12.0 ±7.1 years for UKA (n.s.). The Knee Society knee and function scores, WOMAC, and range of motion (ROM) were investigated. The mechanical axis and femorotibial angle were evaluated. Kaplan–Meier survival analysis was performed (failure: revision to TKA), and the failure modes were investigated. Results. Most of the clinical and radiographic results were not different at the last follow-up, except ROM; ROM was 135.3 ±12.3° in HTO and 126.8 ±13.3° in UKA (p=0.005). The 5-, 10-, 15-, and 20-year survival rates were 100%, 91.0%, 63.4%, and 48.3% for closed-wedge HTO, respectively, and 90.5%, 87.1%, 70.8%, and 66.4% for UKA (n.s.). The survival rate was higher than that for UKA until 12 years postoperatively but was higher in UKAs thereafter, following a remarkable decrease in HTO. The most common failure mode was degenerative osteoarthritic progression of medial compartment in HTO and femoral component loosening in UKA. Conclusions. Long-term survival did not differ significantly between closed-wedge HTO and fixed-bearing UKA in patients with similar preoperative demographics and knee conditions. The difference in postoperative ROM and failure mode should be considered when selecting a procedure

Using the Mayo Clinic definition (>62mm in women and >66mm in men), the “jumbo acetabular component” is the most successful method for acetabular revisions now, even in hips with severe bone loss. There are numerous advantages: surface contact is maximised; weight-bearing is distributed over a large area of the pelvis; the need for bone grafting is reduced; and usually, hip center of rotation is restored. The possible disadvantages of jumbo cups include: may not restore bone stock; may ream away posterior column or wall; screw fixation required; the possibility of limited bone ingrowth and late failure; and a high rate of dislocation due to acetabular size:femoral head ratio. The techniques for a successful jumbo revision acetabular component involve: sizing-“reaming” of the acetabulum, careful impaction to achieve a “press-fit”, and multiple screw fixation. We recommend placement of an ischial screw in addition to dome and posterior column screw fixation. Cancellous allograft is used for any cavitary defects. The contra-indications for a jumbo acetabular cup are: pelvic dissociation; inability to get a rim fit; and inability to get screw fixation. If stability cannot be achieved with the jumbo cup alone, then use of augment(s), bulk allograft, or cup-cage construct should be considered. Using titanium fiber-metal mesh components, we reported the 15-year survival of 129 revisions. There was 3% revision for deep infection and only 3% revision for aseptic loosening. There were 13 reoperations for other reasons: wear, lysis, dislocation, femoral loosening, and femoral fracture fixation. The survival was 97.3% at 10 years, but it dropped to 82.8% at 15 years. Late loosening of this fiber metal mesh component is likely related to polyethylene wear and loss of fixation. Dislocation is the most common complication of jumbo acetabular revisions, approximately 10%, and these are multifactorial in etiology and often require revision. Based on our experience, we now recommend use of an acetabular component with an enhanced porous coating (tantalum), highly crosslinked polyethylene, and large femoral heads or dual mobility for all jumbo revisions

Introduction. Femoral component loosening is one of the most common failure modes in cementless total hip arthroplasty (THA). Patient age, weight, gender, osteopenia, stem design and Dorr-C bone have all been proposed as risk factors for poor fixation and subsequent stem subsidence and poor outcome. With the increased popularity of CT-based assistive technologies in THA, (Stryker MAKO and Corin OPSTM), we sought to develop a technique to predicted femoral stem fixation using pre-operative CT. Methods. Fourteen patients requiring THA were randomly selected from a previous study investigating component alignment. Mean age was 64 (53 to 76), and 57% were female. All patients received pre-operative CT for 3D dynamic templating (OPSTM), and a TriFit stem and Trinity cup (Corin, UK) implanted through a posterior approach. Post-operatively, patients received an immediate CT and AP x-ray prior to leaving the hospital, and a 1-year follow-up x-ray. On both the immediate post-op x-ray and 1-year follow-up x-ray, the known cup diameter was used to scale the image. On both images, the distance between the most superior point of the greater trochanter and the shoulder of the stem was measured. The difference was recorded as stem subsidence. Subsidence greater than 4mm was deemed clinically relevant. The post-operative CT was used to determine the precise three-dimensional placement of the stem immediately after surgery by registering the known 3D implant geometry to the CT. For each patient, the achieved stem position from post-op CT was then virtually implanted back into the pre-operative OPSTM planning software. The software provides a colour map of the bone density at the stem/bone interface using the Hounsfield Units (HU) of each pixel of the CT [Fig. 1]. Blue represents low density bone transitioning through to green and then red (most dense). Results. Mean stem subsidence was 2.1mm (0.2mm to 11.1mm). Two patients had clinically relevant subsidence. The first stem in a 68M subsided 11.1mm. The second in a 58M subsided 5.0mm. Both density colour plots had significant areas of blue (low density bone) around the proximal portion of the stem, with minimal medium/high density fixation when compared to the stems with minimal subsidence. Discussion. Using the Hounsfield units of the CT scan as an indicator for bone density, we were able to predict poor implant fixation and subsequent subsidence in a taper wedge stem. This new technology might have pre-operative value in providing a more quantitative measure of fixation and resultant stem choice. For any figures or tables, please contact the authors directly

Tapered fluted grit-blasted modular stems have now become established as a successful method of femoral revision. The success of these stems is predicated on obtaining axial stability by milling the femur to a cone and then inserting the tapered prosthesis into that cone. Torsional stability is gained by flutes that cut into the diaphysis. By having modular proximal segments of different lengths, the leg length, offset, and anteversion can be adjusted after the distal stem is fixed. This maximises the chance for the stem to be driven into the canal to whatever level provides maximum stem stability. Modular fluted tapered stems have the potential benefits of being made of titanium and hence being both bone friendly and also having a modulus of elasticity closer to that of bone. They have a well-established high rate of fixation. Drawbacks include the risk of fracture of modular junctions and tapers, and difficulty of extraction. The indications for the use of these implants vary among surgeons, but the implants are suitable for use in a wide variety of bone loss categories. Non-modular fluted tapered stems also can gain excellent fixation, but are less versatile and in most practices are used for selected simpler revisions. Results from a number of institutions in North America and Europe demonstrate high rates of implant fixation. In a recently published paper from Mayo Clinic, the 10-year survivorship, free of femoral aseptic loosening revision, of a modular fluted tapered stem was 98% and the stem performed well across a wide range of bone deficiencies. The technique of implantation will be described in a video during the presentation

Young osteoarthritic male patients have been considered the ideal candidates for Metal-on-Metal (MoM) hip resurfacing arthroplasty (HRA), based on generally good long term results. In contrast, hip resurfacing in young female patients has become controversial. Recently, one implant manufacturer withdrew 46mm and smaller components, citing poorer than expected 10 year outcomes in females with smaller HRAs. Whether this difference is related to gender or to component size is still debated. Possible reasons for higher failure rates reported in females include higher rates of hip dysplasia, poorer bone quality and the risk of higher wear in some smaller sized implants with low cup coverage angles. We reviewed HRA revision specimens with the aim of comparing mode of failure, time to revision, femoral cement characteristics and acetabular bone attachment in specimens larger and smaller than 46mm and from male versus female patients. Methods. The study included all of the MoM HRA devices in our collection. Of the 284 hip resurfacing devices with complete clinical information, 131 were from male and 153 from female patients. Femoral sizes ranged from 36 – 58mm, median and mode 46mm; median size in females was 44 and 50mm in males. Time to failure ranged from 1 to 178 months, median 24 mos. Seven designs were represented but the majority were Conserve Plus (n=105 WMT, USA) and BHR (n=78 Smith & Nephew, USA) which differ in cementing technique. 131 femoral components were sectioned and the width of the cement mantle and the amount of cement in the head were measured. Where available, the amount of bone attached to the cup porous surface (n=91), tissue ALVAL scores (n=75) and bearing wear depth (n=138) were included in the multivariate analysis. Results. As a function of gender, there were no significant differences in time to revision, cement measurements or ALVAL scores. Wear depth was significantly higher in females (femoral 41um vs 21um; cup 50um vs 16um, p=0.05). As a function of size (46 and less = small), the <46mm group had a slightly shorter time to revision, 30 vs 38 months, p=0.04). Bone ingrowth ranged from 0 to 60% (Figure 1) and significantly less bone attachment was noted in both the smaller and larger components (p = 0.001). Other characteristics were similar in both groups. When wear-related failure modes (cup malposition, lysis, high ions) were compared, no differences between male and female or large vs small were found. The amount of cement in the femoral heads covered a wide range but femoral loosening or fracture rates were not different as a function of size or gender. Conclusion. This review of 248 revised HRAs from multiple surgeons, designs and modes of failure found no clear evidence that smaller HRA components were at higher risk of earlier failure or for any particular failure mode. The small components in this cohort were not more likely to have wear-related failures but of note, very few of these HRAs had implants with low coverage angles in the small sizes

Hip resurfacing, like other orthopaedic procedures, depends for its success upon the confluence of three factors: a well-designed device, implanted using good technique, in a properly selected patient. Cleveland Clinic has had good mid-term results in more than 2,200 patients using the Birmingham device since its FDA approval in 2006. These results are quite similar to other reported series from many centers around the world. All surgery was performed using an anterolateral approach. Males accounted for 72% of the patients, and the average age was 53 years (12‐84). More than 90% of the patients had a diagnosis of osteoarthritis, and femoroacetabular impingement was the predominant pathology. The average component head size in males was 51mm, and in females 45mm. Complications were few, with no dislocations, no femoral loosening, one socket loosening, one head collapse, 2 femoral neck fractures, and 2 deep infections. There were two patients with metallosis, one due to component malposition, and one in a small, dysplastic female. There were no destructive pseudotumors. Overall survivorship at up to 8 years was more than 99%. Survivorship in young males, under age 50 with OA was 100%. New mushroom templates for head size are described. Additional imaging recommendations including a standing lateral of the pelvis, and a CT scan for femoral anteversion may be helpful in patient selection

Tibial and femoral loosening are major causes for implant failure in total knee arthroplasty. Jefferey (1991) reported a significantly lower rate of loosening when varus or valgus was within 3 degrees of mechanical axis in an eight year follow up. Coulle (Dec1999) reported 48% unacceptable alignment in non-navigated knees and Reed (Aug 2002) reported 35% alignments deviating more than 3 degrees from mechanical axis when navigation was not used. We report our series of 286 navigated knee replacements using the Aesculap Search system (21 cases) and the Aesculap e-motion versions 4.2, 4.3 and 4.4 (265 cases) between April 2003 and December 2012 by the author (A.D) and analysed the correction achieved against the zero mechanical axis. Postoperative measurement of the angles on long length films was done in 23 cases. This matched with the intraoperative corrections achieved as studied using per-operative computer data stored for every case. We continued to use the data stored in the AESCULAP System to correlate the findings in the rest of the cases. The average mechanical axis achieved was 1.3 degrees. All cases had mechanical axes within 3 degrees. We were thus able to achieve a high level of correction of the mechanical axes predictable to achieve better clinical outcomes