Introduction

To utilize existing cancellous bone for initial stability, custom-made stems were implanted without reaming and rasping. This study reviewed the results of this non-reaming technique.

Introduction

One of the objectives of total hip arthroplasty is to restore femoral and acetabular combined anteversion. It is desirable to reproduce both femoral and acetabular antevesions to maximize the acetabular cup fixation coverage and hip joint stability. Studies investigated the resultant of implanted femoral stem anteversion in western populations showed that the implanted femoral stems had only a small portion can meet the desirable femoral anteversion angle¹, and anteversion angle increases after the implantation of an anatomical femoral stem with anteverted stem neck comparing to anatomical femoral neck². The purpose of this study was to anatomically measure the anteversion angular difference between metaphyseal long axis and femoral neck in normal Chinese population. The metaphyseal long axis represents the coronal fixation plane of modern cementless medial-lateral cortical fitting taper stem. This angular difference or torsion Δ angle provides the estimation of how much the neck antevertion angle of femoral stem would be needed to match for desirable anatomical femoral neck version.

Introduction. Traditionally, conventional radiographs of the hip are used to assist surgeons during the preoperative planning process, and these processes generally involve two-dimensional X-ray images with implant templates. Unfortunately, while this technique has been used for many years, it is very manual and can lead to inaccurate fits, such as “good” fits in the frontal view but misalignment in the sagittal view. In order to overcome such shortcomings, it is necessary to fully describe the morphology of the femur in three dimensions, therefore allowing the surgeon to successfully view and fit the components from all possible angles. Objective. The objective of this study was to efficiently describe the morphology of the proximal femur based on existing anatomical landmarks for use in surgical planning and/or forward solution modeling. Methods. Seven parameters are needed to fully define femoral morphology: head diameter, head center, neck shaft axis, femoral canal, proximal shaft axis, offset, and neck shaft angle. A previous algorithm has been developed in-house to automatically locate anatomical landmarks of patient specific bone models. Once the bone model has been aligned and scaled based on these landmarks, the femoral head diameter and center are calculated by iteratively fitting a sphere to the corresponding femoral head point cloud. An iterative cylindrical fitting algorithm is used to describe the neck shaft axis. The femoral canal is determined using three steps: 1) the femur is sliced at 10mm increments below the lesser trochanter, 2) the femoral canal boundary is determined at each slice, and 3) the largest circle is fit within each slice's canal boundary. The proximal shaft axis is described by fitting a line to the canal circle center locations. Offset is defined as the distance from the head center to the proximal shaft axis. Finally, the neck shaft angle is the angle between the neck shaft axis and the proximal shaft axis. Results. The goal pertaining to femoral component morphology is to provide meaningful information that can be used to determine how the femoral stem fits within the canal. Regardless of differences in bone sizes and geometries, the algorithm has proven to be successful in describing the femoral morphology of a patient-specific bone model. Discussion. These results lay the groundwork for an automatic stem fitting algorithm, which is described in a subsequent abstract. The morphology knowledge of the femoral head, femoral neck, femoral canal, and various axes can be coupled with known THA component parameters (such as offset, neck length, neck shaft angle, etc.) to allow our algorithms to predict the “best selection” and “best fit” for the femoral stem. This can also be applied to the acetabulum and can then be used as a surgical planning tool as well as a parameter when modeling postoperative predictions. For any figures or tables, please contact authors directly

The number of cemented femoral stems implanted in the United States continues to slowly decrease over time. Approximately 10% of all femoral components implanted today are cemented, and the majority are in patients undergoing hip arthroplasty for femoral neck fractures. The European experience is quite different. In the UK, cemented femoral stems account for approximately 50% of all implants, while in the Swedish registry, cemented stems still account for the majority of implanted femoral components. Recent data demonstrating some limitations of uncemented fixation in the elderly for primary THA, may suggest that a cemented femoral component may be an attractive alternative in such a group. Two general philosophies exist with regards to the cemented femoral stem: Taper slip and Composite Beam. There are flagship implants representing both philosophies and select designs have shown excellent results past 30 years. A good femoral component design and cementing technique, however, is crucial for long-term clinical success. The author's personal preference is that of a “taper slip” design. The cemented Exeter stem has shown excellent results past 30 years with rare cases of loosening. The characteristic behavior of such a stem is to allow slight subsidence of the stem within the cement mantle through the process of cement creep. One or two millimeters of subsidence in the long-term have been observed with no detrimental clinical consequences. There have been ample results in the literature showing the excellent results at mid- and long-term in all patient groups. The author's current indication for a cemented stem include the elderly with no clear and definitive cutoff for age, most likely in females, THA for femoral neck fracture, small femoral canals such as those patients with DDH, and occasionally in patients with history of previous hip infection. Modern and impeccable cement technique is paramount for durable cemented fixation. It is important to remember that the goal is interdigitation of the cement with cancellous bone, so preparing the femur should not remove cancellous bone. Modern technique includes distal plugging of the femoral canal, pulsatile lavage, drying of the femoral canal with epinephrine or hydrogen peroxide, retrograde fill of the femoral canal with cement with appropriate suction and pressurization of the femoral cement into the canal prior to implantation of the femoral component. The dreaded “cement implantation syndrome” leading to sudden death can be avoided by appropriate fluid resuscitation prior to implanting the femoral component. This is an extremely rare occurrence today with reported mortality for the Exeter stem of 1 in 10,000. A cemented femoral component has been shown to be clinically successful at long term. Unfortunately, the art of cementing a femoral component has been lost and is rarely performed in the US. The number of cemented stems, unfortunately, may continue to go down as it is uncommonly taught in residency and fellowship, however, it might find a resurgence as the limits of uncemented fixation in the elderly are encountered. National joint registers support the use of cemented femoral components, and actually demonstrate higher survivorship at short term when compared to all other uncemented femoral components. A cemented femoral component should be in the hip surgeons armamentarium when treating patients undergoing primary and revision THA

This technique is a novel superior based muscle sparing approach. Acetabular reaming in all hip approaches requires femoral retraction. This technique is performed through a hole in the lateral femoral cortex without the need to retract the femur. A 5 mm hole is drilled in the lateral femur using a jig attached to the broach handle, similar to a femoral nail. Specialised instruments have been developed, including a broach with a hole going through it at the angle of the neck of the prosthesis, to allow the rotation of the reaming rod whilst protecting the femur. A special C-arm is used to push on the reaming basket. The angle of the acetabulum is directly related to the position of the broach inside the femoral canal and the position of the leg. A specialised instrument allows changing of offset and length without dislocating the hip during trialling. Some instrumentation has been used in surgery but ongoing cadaver work is being performed for proof of concept. The ability to ream through the femur has been proven during surgery. The potential risk to the bone has been assessed using finite analysis as minimal. The stress levels for any diameter maintained within a safety factor >4 compared to the ultimate tensile strength of cortical bone. The described technique allows for transfemoral acetabular reaming without retraction of the femur. It is minimally invasive and simple, requiring minimal assistance. We are incorporating use with a universal robot system as well as developing an electromagnetic navigation system. Assessment of the accuracy of these significantly cheaper systems is ongoing but promising. This approach is as minimally invasive as is possible, safe, requires minimal assistance and has a number of other potential advantages with addition of other new navigation and simple robotic attachments

The number of cemented femoral stems implanted in the United States continues to slowly decrease over time. Approximately 10% of all femoral components implanted today are cemented, and the majority are in patients undergoing hip arthroplasty for femoral neck fractures. The European experience is quite different, in the UK, cemented femoral stems account for approximately 50% of all implants, while in the Swedish registry, cemented stems still account for the majority of implanted femoral components. Recent data demonstrating some limitations of uncemented fixation in the elderly for primary THA, may suggest that a cemented femoral component may be an attractive alternative in such a group. Two general philosophies exist with regards to the cemented femoral stem: Taper slip and Composite Beam. There are flagship implants representing both philosophies and select designs have shown excellent results past 30 years. A good femoral component design and cementing technique, however, is crucial for long-term clinical success. The authors' personal preference is that of a “taper slip” design. The cemented Exeter stem has shown excellent results past 30 years with rare cases of loosening. The characteristic behavior of such a stem is to allow slight subsidence of the stem within the cement mantle through the process of cement creep. One or two millimeters of subsidence in the long-term have been observed with no detrimental clinical consequences. There have been ample results in the literature showing the excellent results at mid- and long-term in all patient groups. The authors' current indications for a cemented stem include the elderly with no clear and definitive cutoff for age, most likely in females, THA for femoral neck fracture, small femoral canals such as those patients with DDH, and occasionally in patients with history of previous hip infection. Modern and impeccable cement technique is paramount for durable cemented fixation. It is important to remember that the goal is interdigitation of the cement with cancellous bone, so preparing the femur should not remove cancellous bone. Modern technique includes distal plugging of the femoral canal, pulsatile lavage, drying of the femoral canal with epinephrine or hydrogen peroxide, retrograde fill of the femoral canal with cement with appropriate suction and pressurization of the femoral cement into the canal prior to implantation of the femoral component. The dreaded “cement implantation syndrome” leading to sudden death can be avoided by appropriate fluid resuscitation prior to implanting the femoral component. This is a extremely rare occurrence today with reported mortality for the Exeter stem of 1 in 10,000. A cemented femoral component has been shown to be clinically successful at long term. Unfortunately, the art of cementing a femoral component has been lost and is rarely performed in the US. The number of cemented stems unfortunately may continue to go down as it is uncommonly taught in residency and fellowship, however it might find a resurgence as the limits of uncemented fixation in the elderly are encountered. National joint registers support the use of cemented femoral components, and actually demonstrate higher survivorship at short term when compared to all other uncemented femoral components. A cemented femoral component should be in the hip surgeons' armamentarium when treating patients undergoing primary and revision THA

Introduction. Osteogenesis imperfect (OI) is a geno- and phenotypically heterogeneous group of congenital collagen disorders characterized by fragility and microfractures resulting in long bone deformities. OI can lead to progressive femoral coxa vara from bone and muscular imbalance and continuous microfracture about the proximal femur. If left untreated, patients develop Trendelenburg gait, leg length discrepancy, further stress fracture and acute fracture at the apex of the deformity, impingement and hip joint degeneration. In the OI patient, femoral coxa vara cannot be treated in isolation and consideration must be given to protecting the whole bone with the primary goal of verticalization and improved biomechanical stability to allow early loading, safe standing, re-orientation of the physis and avoidance of untreated sequelae. Implant constructs should therefore be designed to accommodate and protect the whole bone. The normal paediatric femoral neck shaft angle (FNSA) ranges from 135 to 145 degrees. In OI the progressive pathomechanical changes result in FNSA of significantly less than 120 degrees and decreased Hilgenreiner epiphyseal angles (HEA). Proximal femoral valgus osteotomy is considered the standard surgical treatment for coxa vara and multiple surgical techniques have been described, each with their associated complications. In this paper we present the novel technique of controlling femoral version and coronal alignment using a tubular plate and long bone protection with the use of teleoscoping rods. Methodology. After the decision to operate had been made, a CT scan of the femur was performed. A 1:1 scale 3D printed model (AXIAL3D, Belfast, UK) was made from the CT scan to allow for accurate implant templating and osteotomy planning. In all cases a subtrochanteric osteotomy was performed and fixed using a pre-bent 3.5 mm 1/3 tubular plate. The plate was bent to allow one end to be inserted into the proximal femur to act as a blade. A channel into the femoral neck was opened using a flat osteotome. The plate was then tapped into the femoral neck to the predetermined position. The final position needed to allow one of the plate holes to accommodate the growing rod. This had to be determined pre operatively using the 3D printed model and the implants. The femoral canal was reamed, and the growing rod was placed in the femur, passing through the hole in the plate to create a construct that could effectively protect both the femoral neck and the full length of the shaft. The distal part of the plate was then fixed to the shaft using eccentric screws around the nail to complete the construct. Results. Three children ages 5,8 and 13 underwent the procedure. Five coxa vara femurs have undergone this technique with follow-up out to 62 months (41–85 months) from surgery. Improvements in the femoral neck shaft angle (FNSA) were av. 18. o. (10–38. o. ) with pre-op coxa vara FNSA av. 99. o. (range 87–114. o. ) and final FNSA 117. o. (105–125. o. ). Hilgenreiner's epiphyseal angle was improved by av. 29. o. (2–58. o. ). However only one hip was restored to <25. o. In the initial technique employed for 3 hips, the plates were left short in the neck to avoid damaging the physis. This resulted in 2 of 3 hips fracturing through the femoral neck above the plate at approximately 1 year. There were revisions of the 3 hips to longer plates to prevent intra-capsular stress riser. All osteotomies united and both intracapsular fractures healed. No further fractures have occurred within the protected femurs and no other repeat operations have been required. Conclusions. Surgical correction of the OI coxa vara hip is complex. Bone mineral density, multiplanar deformity, a desire to maintain physeal growth and protection of the whole bone all play a role in the surgeon's decision making process. Following modifications, this technique demonstrates a novel method in planning and control of multiplanar proximal femoral deformity, resulting in restoration of the FNSA to a more appropriate anatomical alignment, preventing long bone fracture and improved femoral verticalization in the medium term follow-up

Intra-operative fractures of the femur are on the rise mainly due to the increased use of cementless implants and the desire to get a tight press fit. The prevalence has been reported to be between 1–5% in cementless THAs. The key to preventing these fractures is to identify patients at high risk and careful surgical technique. Surgical risk factors include the use of cementless devices, revision hip surgery, the use of flat tapered wedges and MIS surgery. Patient factors that increased risk include increasing age, female gender, osteopenia and rheumatoid arthritis. These risk factors tend to be additive and certainly when more than one is present extra caution needs to be taken. Surgical technique is critical to avoid these intra-operative fractures. Fractures can occur during exposure and dislocation, during implant removal (in revision THA), during canal preparation and most commonly during stem insertion. In both primary, and especially in revision, THA be wary of the stiff hip in association with osteopenia or osteolysis. These patients require a very gentle dislocation. If this cannot be achieved, then alteration of the standard approach and dislocation may be needed. Examples of these include protrusion with an osteopenic femur and revision THA with a very stiff hip with lysis in the femur. Lastly, in cases with retained hardware, dislocate prior to removing plates and screws. After dislocation, the next challenge is gentle preparation of the femoral canal. A reasonable exposure is required to access the femoral canal safely. MIS procedures do not offer good access to femoral canal and this probably results in increased risk of fracture during broaching or implant insertion. When broaching, stop when broach will not advance further. When inserting a tapered wedge stem, be worried if stem goes further in than broach. In revision surgery, when taking the stem out from above, make sure the area of the greater trochanter does not overhang the canal. A high speed burr can clear the shoulder for easier access for removal. In revision THA with an ETO, place a cerclage wire prior to reaming and retighten prior to stem insertion. Even with careful surgical technique intra-operative femoral fractures will still occur. When inserting the stem, a sudden change in resistance is highly suggestive of fracture. Wide exposure of the entire proximal femur is necessary to confirm the diagnosis. The distal extent of the fracture must be seen. Only on occasion is an intra-operative radiograph needed. Management is directed to ensuring component stability and good fracture fixation. In primary total hip arthroplasty, calcar fractures are by far the most common. If using proximal fixation and you are certain the stem is stable, then all that is needed is cerclage wiring. As already mentioned, you must follow the fracture line distally so you are aware of how far down it goes. Often what appears to be a calcar split actually propagates distal to the lesser trochanter. In these cases, one would probably go for distal fixation plus wiring. In conclusion, intra-operative femoral fractures are on the rise. Prevention is the key

Background. Cement restrictors are used for maintaining good filling and pressurization of bone cement during hip and knee arthroplasties. The limitations of certain cement restrictors include the inability to accommodate for large medullary canals particularly in revision procedures. We describe a technique using SurgicelTM (Johnson & Johnson) and SPONGOSTAN™ (Johnson & Johnson) (Fig 1) to form a cement restrictor that can accommodate for large canal diameters and provide excellent pressurisation. Technique. The technique involves the application of SPONGOSTAN™ (Johnson & Johnson) foam onto a SurgicelTM (Johnson & Johnson) mesh which is then rolled onto the SPONGOSTAN™ foam forming a uniform cylindrical structure Figs 2,3. The diameter of the restrictor can be adjusted according to the desired femoral canal diameter through increasing the thickness of the SPONGOSTAN™ (Johnson & Johnson) foam. The restrictor is then inserted into the desired position in the medullary canal where it expands uniformly creating an effective restrictor and bone plug Fig 4. Bone cement is then applied and pressurisation commenced prior to the insertion of the implant Fig5. SPONGOSTAN™ is an absorbable haemostatic sponge intended for haemostatic use by applying to a bleeding surface. It consists of a sterile, water-insoluble, malleable, porcine gelatin absorbable sponge. Surgicel ™ is an absorbable hemostatic agent composed of oxidized regenerated cellulose. It is a sterile, absorbable knitted fabric that is flexible and adheres readily to bleeding surfaces. Both products are routinely used for their haemostatic properties in various surgical disciplines. Discussion. The use of intramedullary plugs in cemented total joint arthroplasty is essential in order to achieve good filling and pressurization in hip and knee arthoplasties, traditionally, a small piece of bone or a cement restrictor may be used to plug the shaft. Distal plugs seal the femoral canal, improve fixation and prevent bone cement from leaking during delivery and pressurization. Plugging the intramedullary canal during total hip arthroplasty increases penetration of cement into cancellous bone proximal to the intramedullary plug. Numerous plug designs and materials are available ranging from non-resorbable to resorbable. Regardless of design, all restrictors should avoid intramedullary cement leakage and plug migration during cement and stem insertion to ensure adequate intramedullary pressures. In some instances the diameter of the femoral canal is too wide to accommodate a conventional cement restrictor particularly when crossing the femoral isthmus and even more so in revision procedures requiring the implantation of long stemmed cemented components. The use of the Surgicel-Spongostan haemostatic restrictor overcomes some of the limitations of a standard cement restrictors. These include the ability to bypass a narrow femoral isthmus, accommodate large femoral canals, particularly in revision procedures, and the flexibility of adjusting the restrictor to the desired diameter of the medullary canal and in effect providing a bespoke cement restrictor. This technique was used successfully in over 300 revision hip and knee procedures with no adverse effects and excellent outcomes

Introduction. Conventional hip radiographs allow surgeons, during preoperative planning, to make important decisions. Size and location of implants are routinely measured by overlaying schematics of the implanted components onto preoperative radiographs. Most currently available planning tools are in two-dimensions (2D), using X-ray images and 2D templates of the implants. Determination of the ideal component size requires two radiographic views of the femur: the anterior-posterior (AP) and the lateral direction. The surgeon uses this information to determine component sizes. Even though this approach has been used for many years leading to very good results, this manual process potentially carries multiple shortcomings. The biggest issue with the AP X-ray image is the fact that it is 2D in nature while the measurement's objective is to obtain three-dimensional (3D) parameters. Objective. The objective of this study is to derive a methodology to automatically select correct THA implant sizes while keeping the anatomical center of each specific patient within a forward solution model (FSM) that predicts post-operative outcomes. Methods. The femoral components in our process contain five parameters: stem length, neck offset, neck length, neck shaft angle, and component width. There are many steps to measure the morphologic parameters of a femoral component. (1)Preparation of training implant database, (2)defining multi-plane intersection, (3)determining circumcircles for all intersected femoral component contours, (4)finding centers and radii of circumcircles, (5)measuring distances from each circumcircle to the femoral component head center, and (6)determining the stem shaft axis. The FSM fits specific femoral canal using a 3D mesh model of the femur. The femoral component and canal morphology of a femur model are compared to the training femoral component database. For each femoral component morphology, the algorithm determines how far distally the femoral component fits within the canal before collision between the stem and cortical bone. Once the defined position is confirmed, the relative distance from the anatomical femoral head center to the femoral component head center is calculated. This process is repeated for all femoral component morphology. The best fitting femoral component is determined when the distance from its head center to the femoral head center is minimized, Figure 1. Results. Three intensive validation tools have been developed: (1) cross-sectional analysis, (2) slice analysis, and (3) contact map analysis. Cross-sectional analysis is a graphic interaction program where users can freely view the anatomy at any orientation, Figure 2. The slice analysis enhances the user visualization by providing a static view of the fit between chosen femoral component and femoral canal, Figure 3. Finally, the contact map analysis allows for visualization of contact area through the bone-stem interface. Conclusion and Discussion. This is a powerful tool with the FSM that allows surgeons to get a “best fit” implant in 3D, based on canal fit and distance from anatomical femoral head center. Surgeons may want to manually size up or down, but the program will pick best fit sizes based on anatomical morphology. Future iterations will consider the reaming depth each surgeon uses to improve implant selection for each surgeon's technique. For any figures or tables, please contact authors directly

Background. Aseptic loosening is rare with most cementless tapered stems in primary total hip arthroplasty (THA), however different factors can modify results. We ask if the shape and technique of three current different femoral components affects the clinical and radiological outcome after a minimum follow-up of ten years. Methods. 889 cementless tapered stems implanted from 1999 to 2007 were prospectively followed. Group 1 (273 hips) shared a conical shape and a porous-coated surface, group 2 (286 hips) a conical splined shape and group 3 (330 hips) a rectangular stem. Clinical outcome and anteroposterior and sagittal radiographic analysis were compared. Femoral type, stem position, femoral canal filling at three levels and the possible appearance of loosening and bone remodelling changes were assessed. Results. No thigh pain was reported in unrevised patients. Mean Harris Hip score was lower for patients in group 3 for pain and function at 6 months, two years and at latest follow-up. The survival rate of not having revision of the stem for any cause was 98.5% (95% CI 98.8–100) for group 1 at 12 years, 99.3 % ((95% Confidence Intervals (CI) 97.9–100) for group 2 at 16 years and 97.7% (95% (CI) 94–100) for group 3 at 14 years, and (log rank= 0.109). Thirteen stems from the latter were revised for aseptic loosening. No revision for aseptic loosening was found in the other designs. After controlling all confounding factors, the risk for aseptic loosening in group 3 was related to a lower femoral canal filling (p=0.039, Hazard Ratio (HR):0.918, 95% Confidence Interval (CI):0.846–0.996) and a stem position outside neutral limits in the sagittal alignment (p=0.048, HR:3.581, 95% CI:1.010–12.696). Conclusions. Conical tapered cementless stems are more reliable than rectangular straight designs in primary THA after ten years

Background. Despite the success of total hip arthroplasty (THA), there are still challenges including restoration of leg length, offset, and femoral version. The Tsolution One combines preoperative planning with an active robotic system to assist in femoral canal preparation during a THA. Purpose of Study. To demonstrate the use of an active robotic system in femoral implant placement and determine the accuracy of femoral implant position. This was evaluated in a cadaveric study. Study Design and Methods. Four THA's were performed in fresh frozen cadaveric hips with assistance of the TSolution One System for preparation of the femoral canal. CT scans of the hip were used as input for TPLAN preoperative planning software to position the implants in three-dimensions (3D). The intraoperative process includes exposure of the joint using a posterolateral approach, fixation of the femur relative to the TCAT system, and registration of the femur. TCAT then actively milled the femoral canal in each of the cases after which Depuy Trilock implants were inserted by the surgeon. Only the femoral stem implants were considered in this study. Postoperative CT was used to compare actual implant position with preoperatively planned implant position in 3D. The translations between the centroids of the implant positions were compared. Findings of Study. All femoral stems were successfully implanted with no complications. Implant position very closely matched the preoperative plan. Compared to the preoperative plan, the mean (± SD) positions of the centroid of the implant were off by 0.6 (±0.6) mm in the medial-lateral direction, 0.8 (±0.3) mm in the anterior-posterior direction, and 2.0 (±1.3) mm in the superior-inferior direction. No intraoperative fractures occurred. A sample of the preoperative planned position (left) and actual postoperative position (right) as seen on TPLAN can be seen in Figure 1. An example of the final 3D implant position in blue as compared to the preoperative implant position in red can be seen in Figure 2. Conclusions. Overall, the post-operative stems positions were superior compared to the preoperative plan and it is believed that this is likely a result of not impacting the stems enough during the procedure. The medial-lateral and anterior-posterior stem positions were within 1 mm of what was planned. Active robotics can successfully be used to improve accuracy, precision, and reproducibility when considering final implant position in THA. These improvements can reduce unwanted human error and reduce complications. Further in vivo study is planned to demonstrate the clinical benefits of such improved precision

Background and aim. Despite good survivorship analysis for most uncemented tapered straight stems, new proposals modifying stem design in total hip replacement (THR) are being introduced in order to facilitate femoral revision surgery. We have evaluated the clinical and radiological results of four different designs of uncemented tapered straight stems implanted in our institution in order to assess: operative complications, clinical results, survivorship analysis for aseptic loosening and radiographic findings. Methods. 1008 hips implanted from 1998 to 2006 were prospectively followed for a mean of 12 years (range, 10 to 17). Four uncemented femoral designs employing a tapered straight stem were included: 209 Alloclassic stems, 420 Cerafit, 220 SL-Plus and 159 Summit. All hips had a 28 or 32 mm femoral head, and polyethylene (PE)-on metal or ceramic-on-ceramic bearing surface. Radiological femoral type, stem position, femoral canal filling at three levels and the possible appearance of loosening and other bone remodelling changes were recorded in all hips. Results. The rate of intra- and post-operative peri-prosthetic fractures ranged from 0 to 2.5%. No thigh pain was reported in unrevised patients. Among all groups, a total of 15 stems were revised for any cause. The revision rates for any cause at 12 years ranged from 97.1 to 99.3%. (p=0.1). 10 femoral components were revised for aseptic loosening: 6 Alloclassic stems with PE liner sterilized by Nitrogen and 3 SL-Plus stems with standard PE. No revision for aseptic loosening was found in the other designs. The survival rate for stem aseptic loosening was 97.1% (95% CI 95.6–100) for the Alloclassic group at 17 years and 98.2% (95% CI 96.2–100) for the SL-Plus at 14 years. The percentage with a neutral stem position was lower in the Alloclassic and SL-Plus groups (p=0.04). We found that femoral canal filling depended on stem group and stem position at three levels A, B and C (p<0.001). Femoral canal filling was greater in the SL-Plus group at three levels than the others (p<0.001). Bone remodelling changes were more frequent in the SL-Plus group, radiolucent lines (p<0.001) and cortical hypertrophy (p<0.001). Conclusion. Uncemented tapered straight stems consistently provide excellent clinical outcome and bone fixation. Newer proposals must consider these results, avoiding changing successful characteristics and concentrate on improving the less successful aspects

Intra-operative fractures of the femur are on the rise mainly due to the increased use of cementless implants and the desire to get a tight pressfit. The prevalence has been reported to be between 1–5% in cementless total hip arthroplasties (THAs). The key to preventing these fractures is to identify patients at high risk and careful surgical technique. Surgical risk factors include the use of cementless devices, revision hip surgery, the use of flat tapered wedges and MIS surgery. Patient factors that increased risk include increasing age, female gender, osteopenia and rheumatoid arthritis. These risk factors tend to be additive and certainly when more than one is present extra caution needs to be taken. Surgical technique is critical to avoid these intra-operative fractures. Fractures can occur during exposure and dislocation, during implant removal (in revision THA), during canal preparation and most commonly during stem insertion. In both primary and especially in revision THA, be wary of the stiff hip in association with osteopenia or osteolysis. These patients require a very gentle dislocation. If this cannot be achieved, then alteration of the standard approach and dislocation may be needed. Examples of these include protrusion with an osteopenic femur and revision THA with a very stiff hip with lysis in the femur. Lastly, in cases with retained hardware, dislocate prior to removing plates and screws. After dislocation, the next challenge is gentle preparation of the femoral canal. A reasonable exposure is required to access the femoral canal safely. MIS procedures do not offer as good access to femoral canal and this probably results in increased risk of fracture during broaching or implant insertion. When broaching, stop when broach will not advance further. When inserting a tapered wedge stem, be worried if stem goes further in than broach. In revision surgery when taking the stem out from above, make sure the greater trochanter does not overhang the canal. A high speed burr can clear the shoulder for easier access for removal. In revision THA with an ETO place a cerclage wire prior to reaming and retighten prior to stem insertion. Even with careful surgical technique intra-operative femoral fractures will still occur. When inserting the stem a sudden change in resistance is highly suggestive of fracture. Wide exposure of the entire proximal femur is necessary to confirm the diagnosis. The distal extent of the fracture must be seen. Only on occasion is an intra-operative radiograph needed. Management is directed to ensuring component stability and good fracture fixation. In primary total hip arthroplasty calcar fractures are by far the most common. If using proximal fixation and you are certain the stem is stable, then all that is needed is cerclage wiring. As already mentioned, you must follow the fracture line distally so you are aware of how far down it goes. Often what appears to be a calcar split actually propagates distal to the lesser trochanter. In these cases, one would probably go for distal fixation plus wiring. In conclusion intra-operative femoral fractures are on the rise. Prevention is the key. If a fracture, exposure is the key to deciding on a treatment plan

Background. Cemented femoral stems have an excellent long-term outcome. Modern cement techniques should be used to optimize femoral stem fixation. Bleeding from the bone surface during cemented hip arthroplasty compromises the bone-cement interface. However, no studies have examined this bleeding in vivo nor the effect the different cleaning methods used. In the present study we evaluated bleeding patterns and efficacy of cleaning methods used in third generation cementing techniques. Methods. We prospectively performed a medulloscopy with a 10 mm laparoscope in 200 primary hip arthroplasties. Intramedullary bleeding was evaluated after femoral canal preparation and use of the different cleaning methods. The femoral canal was divided into three areas to facilitate comparison. The intramedullary bleeding was standardized on a four point scale. A non-parametric repeated measures ANOVA was used for statistical analysis. Results. Cotton swabs and brushes did not reduce the intramedullary bleeding significantly after broaching of the canal. Compared to these standard cleaning methods, pulsed lavage and the addition of brushing provided better blood removal (p<0.001). There was a trend, although not statistical significant (p=0.24), towards better canal cleaning if a canal filling tampon with suction was added. Arterial bleeding originating from the posterior wall of the canal was noticed in 26 cases (13 percent). These could only be controlled by diathermy tools. Conclusion. Most standard preparation techniques are insufficient to prepare the femoral canal before cement insertion. In case of severe intramedullary bleeding, an arterial bleeding should be ruled out and if necessary treated with the aid of diathermy tools. We recommend pulsed lavage combined with a brush and a canal filling tampon for femoral canal preparation in cemented primary hip arthroplasty for optimal reduction of intramedullary bleeding

Background. The use of robotics in joint arthroplasty was initiated in 1992 with the introduction of the ROBODOC® Surgical Assistant device for planning and active robotic preparation of the femoral canal in THA. From 1993–1996, an FDA trial was undertaken using pin-based fiduciary markers to register the CT to the robot coordinate system. From 2000–2006, a second FDA trial was initiated using a point-to-surface matching “pinless” registration system. Combined, these two studies offer the first long-term follow-up of robot-assisted THA using an active robotic system for preparation of the femoral canal during THA. Methods. Due to the support of an open implant architecture, patients were implanted with either the Depuy AML, Howmedica Osteoloc, or Zimmer VerSys FMT. Combining patients from the two studies, 86 THA's were performed in 63 patients using the active robotic system. Of these 63 patients, 7 were confirmed to have died and 5 have been lost to follow-up, 2 declined to participate due to infirmity, 37 are still recruiting, and 12 are currently enrolled (16 hips). Data collected included: Harris Hip Scale, HSQ-12, WOMAC, UCLA Activity Score, VAS Pain Score as well as radiographic analysis. The demographics at follow-up were:. Results. There were no revisions of the femoral component for aseptic reasons. Of the 16 hips enrolled, only two have required reoperation for head and liner change. Clinical results are given below:. Radiographic analysis found that peri-acetabular osteolysis was present in 12.5% of hips, AP femoral osteolysis was found in 18.8% of hips, above and lateral femoral osteolysis was found in 6.3% of cases. Conclusions. The use of active robotics for preparation of the femoral canal in THA appears safe and effective at a long-term follow-up of 14 years. The clinical results are comparable to or better than other long term studies of cementless femoral stem prostheses in terms of Harris Hip score (Aldinger et al 2003) and WOMAC Pain, Stiffness, and Physical Function score (Popischill and Knahr 2005). Patient recruitment is still ongoing

Femoral revision after cemented total hip arthroplasty (THA) might include technical difficulties, following essential cement removal, which might lead to further loss of bone and consequently inadequate fixation of the subsequent revision stem. Bone loss may occur because of implant loosening or polyethylene wear, and should be addressed at time of revision surgery. Stem revision can be performed with modular cementless reconstruction stems involving the diaphysis for fixation, or alternatively with restoration of the bone stock of the proximal femur with the use of allografts. Impaction bone grafting (IBG) has been widely used in revision surgery for the acetabulum, and subsequently for the femur in Paprosky defects Type 1 or 2. In combination with a regular length cemented stem, impaction grafting allows for restoration of femoral bone stock through incorporation and remodeling of the proximal femur. Cavitary bone defects affecting the metaphysis and partly the diaphysis leading to a wide femoral canal are ideal indications for this technique. In case of combined segmental-cavitary defects a metal mesh is used to contain the defect which is then filled and impacted with bone grafts. Cancellous allograft bone chips of 2 to 4 mm size are used, and tapered into the canal with rods of increasing diameters. To impact the bone chips into the femoral canal a dummy of the dimensions of the definitive cemented stem is inserted and tapped into the femur to ensure that the chips are firmly impacted. Finally, a standard stem is implanted into the newly created medullary canal using bone cement. To date several studies from Europe have shown favorable results with this technique, with some excellent long-term results reported. Advantages of IBG include the restoration of the bone stock in the proximal femur, the use of standard length cemented stems and preserving the diaphysis for re-revision. As disadvantages of the technique: longer surgical time, increased blood loss and the necessity of a bone bank can be mentioned

Background and aim. Recent proposals have been introduced to modify stem design and/or femoral fixation in total hip replacement (THR). New designs need to consider previous design features and their results. The aim of this study has been to evaluate the clinical and radiological results of six different designs of tapered uncemented stems implanted in our Institution. Methods. 1918 uncemented hips were prospectively assessed from 1999 to 2011 (minimum follow-up of five years for the unrevised hips). All hips had a 28 or 32 mm femoral head and metal-on-polyethylene or alumina-on-alumina bearing surface. Six uncemented femoral designs that shared a femoral tapered stem incorporating a coating surface were included in the study. The different design features included the type of coating, metaphyseal filling, and sectional shape. Results. Intra-operative proximal femoral crack was 6.7% in one of the designs (p=0.01), univariate analysis showing a lower risk of crack in the other designs. The position of the stem was neutral in 80% of the cases for all designs. Femoral canal filing was related to the stem design (p<0.001 at the three levels) and to the femoral level assessed (subset alpha=0.005). Twelve stems were revised for aseptic loosening (6 from two different designs). The survival rate for femoral aseptic loosening at 15 years was 96.6% (95% CI 93.8 to 99.4) for one of these two designs ad 97.4% (95% CI95.5 to 99.6) for the other. Regression analysis showed that stem design was the only factor related to aseptic loosening when adjusted for femoral canal filling (at the three levels) stem position (neutral or not) and femoral type (cylindrical or not). Conclusion. Tapered uncemented stems consistently provide excellent bone fixation. New designs need to avoid changing successful features and concentrate on the less successful aspects

We report on our experience of a THR program set up in Ouagadougou, Burkina Faso (BF). As THR is not performed on a regular basis in this country, we had to start it up completely. We work in BF during a 2 weeks period in December each year. We do this in coöperation with a local surgeon who makes a preselection of THR candidates in advance. This surgeon is trained by us to do the necessary follow up and can contact us all year round in case of specific problems. From 2004 until 2009 we performed 104 operations; these consisted of 98 THR, 2 bipolar hip replacements and 4 revisions. 3 of these revisions were of hip replacements performed by us; 1 revision was of a THR performed in France. Mean age at operation was 48,4 years. All operations were performed by an anterolateral approach with use of cemented implants. Reason for operation was degenerative arthritis in 31 (29,8%), AVN in 39 (37,5%), fracture in 30 (28,9%). Fractures were more than several months old in most cases. Reason for the revision operations was aseptic loosening in 3 cases and periprosthetic fracture in 1. For every operation, technical problems were recorded, if applicable. These problems were not necessarily complicatons. We recorded 50 technical problems in 31 patients. 73 operations (70,2%) were performed without any note of technical problem. Most frequently recorded problems were important shortening of the leg (6), very narrow femoral canal (6), difficult reduction (5), peroperative femoral fracture (4-excluding trochanter maior fracture), extensive fibrosis (4), blocked femoral canal (3). Flexible reamers were used in 5 cases. There were 2 peri-operative deaths: one patient died after a postoperatieve sickle cell crisis with hemolysis. One patient developed a pulmonary embolism. Both patients were Hb SC. We recorded 21 complications in 16 patients. The majority were osseous complications. These were 4 femoral fractures of which 3 had clinical repercussion, 4 trochanteric fractures without any clinical repercussion and 4 peroperative perforations of the femoral canal, all without postoperative clinical repercussion. Other complications were infection (2), paralysis of femoral nerve (1), burn injury by diathermia plate (1), postoperative hemolysis (1), pulmonary embolism (1) and dislocation (2). One infection and dislocation was found in the same patient. This was the patient with revision of a initial THR performed in France. The indications for THR in BF differ significantly form the indications we find in Belgium. We also find the average case in BF more challenging. During the years we have developed specific strategies and schemes based on our experience and the technical problems encountered during the operations. Specific tips and tricks regarding patient selection, technique and equipment will be presented. This can be a good opportunity to learn from our experience for anyone who wants to set up a similar program

As the number of patients who have undergone total hip arthroplasty rises, the number of patients who require surgery for a failed total hip arthroplasty is also increasing. It is estimated that 183,000 total hip replacements were performed in the United States in the year 2000 and that 31,000 of these (17%) were revision procedures. Reconstruction of the failed femoral component in revision total hip arthroplasty can be challenging from a technical perspective and in pre-operative planning. With multiple reconstructive options available, it is helpful to have a classification system which guides the surgeon in selecting the appropriate method of reconstruction. A classification of femoral deficiency has been developed and an algorithmic approach to femoral reconstruction is presented. Type I:. Minimal loss of metaphyseal cancellous bone with an intact diaphysis. Often seen when conversion of a cementless femoral component without biological ingrowth surface requires revision. Type II: Extensive loss of metaphyseal cancellous bone with an intact diaphysis. Often encountered after the removal of a cemented femoral component. Type IIIA: The metaphysis is severely damaged and non-supportive with more than 4cm of intact diaphyseal bone for distal fixation. This type of defect is commonly seen after removal of grossly loose femoral components inserted with first generation cementing techniques. Type IIIB: The metaphysis is severely damaged and non-supportive with less than 4cm of diaphyseal bone available for distal fixation. This type of defect is often seen following failure of a cemented femoral component that was inserted with a cement restrictor and cementless femoral components associated with significant distal osteolysis. Type IV: Extensive meta-diaphyseal damage in conjunction with a widened femoral canal. The isthmus is non-supportive. An extensively coated, diaphyseal filling component reliable achieves successful fixation in the majority of revision femurs. The surgical technique is straightforward and we continue to use this type of device in the majority of our revision total hip arthroplasties. However, in the severely damaged femur (Type IIIB and Type IV), other reconstructive options may provide improved results. Type IIIB:. Based on the poor results obtained with a cylindrical, extensively porous coated implant (with 4 of 8 reconstructions failing), our preference is a modular, cementless, tapered stem with flutes for obtaining rotational stability. Excellent results have been reported with this type of implant and by virtue of its tapered design, excellent initial axial stability can be obtained even in femurs with a very short isthmus. Subsidence has been reported as a potential problem with this type of implant and they can be difficult to insert. However, with the addition of modularity to many systems that employ this concept of fixation, improved stability can be obtained by impaction of the femoral component as far distally as needed while then building up the proximal segment to restore appropriate leg length. Type IV:. The isthmus is completely non-supportive and the femoral canal is widened. Cementless fixation cannot be reliably used in our experience, as it is difficult to obtain adequate initial implant stability that is required for osseointegration. Reconstruction can be performed with impaction grafting if the cortical tube of the proximal femur is intact. However, this technique can be technically difficult to perform, time consuming and costly given the amount of bone graft that is often required. Although implant subsidence and peri-prosthetic fractures (both intra-operatively and post-operatively) have been associated with this technique, it can provide an excellent solution for the difficult revision femur where cementless fixation cannot be utilised. Alternatively, an allograft-prosthesis composite can be utilised for younger patients in an attempt to reconstitute bone stock and a proximal femoral replacing endoprosthesis used for more elderly patients