When removing femoral cement in revision hip surgery, creating an anterior femoral cortical window is an attractive alternative to extended trochanteric osteotomy. We describe our experience and evolution of this technique, the clinical and radiological results, and functional outcomes. Between 2006 and 2021 we used this technique in 22 consecutive cases at Whanganui Hospital, New Zealand. The average age at surgery was 74 years (Range 44 to 89 years). 16 cases were for aseptic loosening: six cases for infection. The technique has evolved to be more precise and since 2019 the combination of CT imaging and 3-D printing technology has allowed patient-specific (PSI) jigs to be created (6 cases). This technique now facilitates cement removal by potentiating exposure through an optimally sized anterior femoral window. Bone incorporation of the cortical window and functional outcomes were assessed in 22 cases, using computer tomography and Oxford scores respectively at six months post revision surgery. Of the septic cases, five went onto successful stage two procedures, the other to a Girdlestone procedure. On average, 80% bony incorporation of the cortical window occurred (range 40 −100%). The average Oxford hip score was 37 (range 22 – 48). Functional outcome (Oxford Hip) scores were available in 11 cases (9 pre-PSI jig and 2 using PSI jig). There were two cases with femoral component subsidence (1 using the PSI jig). This case series has shown the effectiveness of removing a distal femoral cement mantle using an anterior femoral cortical window, now optimized by using a patient specific jig with subsequent reliable bony integration, and functional outcomes comparable with the mean score for revision hip procedures reported in the New Zealand Joint Registry

Introduction. Revision hip arthroplasty with massive proximal femoral bone loss remains challenging. Whilst several surgical techniques have been described, few have reported long term supporting data. A proximal femoral allograft (PFA) may be used to reconstitute bone stock in the multiply revised femur with segmental bone loss of greater than 8 cm. This study reports the outcome of largest case series of PFA used in revision hip arthroplasty. Methods. Data was prospectively collected from a consecutive series of 69 revision hip cases incorporating PFA and retrospective analyzed. Allografts of greater than 8 cm in length (average 14cm) implanted to replace deficient bone stock during revision hip surgery between 1984 and 2000 were included. The average age at surgery was 56 years (range 32–84) with a minimum follow up of 10 years and a mean of 15.8 years (range). Results. From the original cohort four patients had died with the original PFA, 21 (30.4%) patients required further surgery with 14 (20.3%) of these needing revisions of the femoral component. The mean time to femoral revision was 9.5 years and Kaplan-Meier survivorship analysis demonstrates a 79.9% PFA survivorship at 20 years. Discussion. Proximal femoral allograft affords long lasting reconstruction of the femoral component in revision hip surgery. We advocate PFA as an attractive option in the reconstruction of the hip in the presence of significant segmental bone loss in younger patients

Background. Revision total hip arthroplasty is a technically demanding procedure and especially removing a well fixed femoral stem is a challenge for revision surgeons. There are various types of trochanteric osteotomies used during revision surgery; extended trochanteric osteotomy (ETO) is being more popular. Aim. The aim of this study is to look at types of trochanteric osteotomy used during the revision surgery. We looked at the success and failure of these osteotomies. Failure of the osteotomy is defined by complete pull off by the hip abductors resulting in osteotomy fragment is no contact with the femur. We sought to assess the time to healing of osteotomy and number of cables used. Methods. We retrospectively reviewed the hospital theatre database and identified 97 patients who underwent revision hip surgery from June 2008 to December 2015. Among these 35 patients (36% of patients) had trochanteric osteotomy for either extraction of femoral stem or removal of cemented mantle. Results. Most common cause of revision was aseptic loosening in 22 cases (62%) followed by peri prosthetic fracture 6 cases (17%), 1. st. stage of revision surgery in infective cause in 4 cases (11%). Depending on the length of the osteotomy performed we divided the patients into two groups. The first group had osteotomy just around the greater trochanter, which is called short trochanteric osteotomy group and the second group had extended trochanteric osteotomy where the osteotomy length is at least of 15cms and preserving the vastus lateralis attachment to the osteotomy. 7 patients had short trochanteric osteotomy and remaining 28 patients had extended trochanteric osteotomy. In the short trochanteric osteotomy group had 4 out of 6 patients had failure of the osteotomy repair. In extended trochanteric osteotomy group, there was one immediate failure and another one had delayed trochanteric pull off out of 28 patients (93% success rate). The time taken for the osteotomy to heal in short trochanteric osteotomy group was 8 months where as in the extended osteotomy group it was 5 months. The mean number of cables used was 3 in both groups. There was no subsidence seen during the post op follow up in either group. Conclusion. Our study concluded that ETO is a safe procedure with a low complication rate rather than short trochanteric osteotomy. Implications. Awareness about the biomechanics of ETO and its indications can make ETO an important tool in the revision surgeon's armamentarium

Background

The use of tranexamic acid (TEA) can significantly reduce the need for allogenic blood transfusions in elective primary joint arthroplasty. Revision total hip arthroplasty requires increased utilization of post-operative blood transfusions for acute blood loss anemia compared to elective primary hip replacement. There is limited literature to support the routine use of TEA in revision THA.

Studies on soil mechanics have established that when vibration is applied to an aggregate, it results in more efficient alignment of particles and reduces the energy required to impact the aggregate. Our aim was to develop a method of applying vibration to the bone impaction process and assess its effect on the mechanical properties of the impacted graft.

Phase 1. Eighty bovine femoral heads were milled using the Noviomagus bone mill. The graft was then washed using a pulsed lavage normal saline system over a sieve tower. A vibration impaction device was developed which housed two 15V DC motors with eccentric weights attached inside a metal cylinder. A weight was dropped onto this from a set height 72 times so as to replicate the bone impaction process. A range of frequencies of vibration were tested, as measured using an accelerometer housed in the vibration chamber. Each shear test was then repeated at four different normal loads so as to generate a family of stress-strain curves. The Mohr-Coulomb failure envelope from which the shear strength and interlocking values are derived was plotted for each test.

Phase 2. Experiments were repeated with the addition of blood so as to replicate a saturated environment as is encountered during operative conditions.

Relatively dry graft impacted with the addition of vibration showed improved shear strength at all frequencies of vibration when compared to impaction without vibration. In our system the optimal frequency of vibration was 60 Hz. Under saturated conditions the addition of vibration is detrimental the shear strength of the aggregate. This is secondary to decreased interlocking between particles and may be explained by the process of liquefaction.

The process of femoral impaction grafting requires vigorous impaction to obtain adequate stability but the force of impaction has not been determined. This process has been reported to result in femoral fractures with rates reaching 16%. The aims of this study were to determine the threshold force required for femoral impaction grafting, to determine the affect cortical thickness, canal diameter and bone mineral density (BMD) have on this threshold force and to measure subsidence of an Exeter prosthesis following impaction at the threshold force.

Adult sow femurs were prepared and placed through a DEXA scanner and the BMD and canal diameter measured. Thirty five femurs were impacted with morsellised bone chips and an increasing force of 0.5kN was applied until the femur fractured. Using callipers the cortical thickness of the bone was measured along the fracture line. Once the threshold force was determined 5 femurs were impacted to this threshold force and an Exeter stem was cemented into the neomedullary canal and a 28mm Exeter head attached. Axial cyclic loading was performed between 440N (swing phase of gait) and 1320N (stance phase of gait) for 150,000 cycles at a frequency of 3Hz. The position sensor of the hydraulic testing machine measured the subsidence.

29 tests were successfully completed. The threshold force was found to be 4kN. There was no significant correlation between the load at fracture and the cortex: canal ratio or the bone mineral density. Following impaction with the maximum force of 4kN the average subsidence for the 5 femurs was 0.276mm (range 0.235 – 0.325mm). In this animal study the threshold force was 4kN. Minimal axial subsidence of the implant occurred when impacting the graft with this threshold force. We therefore achieved a stable construct without fracture which is the ultimate goal for the revision hip surgeon.

Background. Highly porous acetabular components are widely used in revision hip surgery. The purpose of this study is to compare the mid-term survivorship, clinical and radiological outcomes of a hemispherical cup (Stryker Tritanium Revision component) and a peripherally expanded cup (Zimmer TM modular component) in revision hip surgery. Methods. Between 2010 and 2017, 30 patients underwent revision hip replacement using a hemispherical cup and 54 patients using a peripherally expanded cup. The surgery was carried out by two arthroplasty surgeons, both fellowship-trained in revision hip surgery. Kaplan-Meier analysis was used to determine the survivorship of the components. Clinical outcomes were measured using the Oxford Hip Score. Radiographs were analysed for the presence of radiolucent lines in the DeLee and Charnley zones. Results. Follow up of both components ranged from 2 – 8 years. All the hemispherical cups were reinforced with screws whilst 86% of the peripherally expanded cups required screws. Four (13%) of the hemispherical cups required re-revision surgery for aseptic loosening. One (2%) of the peripherally expanded cups was revised for dislocation, but none for aseptic loosening. None of the peripherally expanded cups exhibited significant radiolucency as compared to 8 (27%) hemispherical cups. The mean Oxford Hip Score of the hemispherical and peripherally expanded cups was 38 and 40 respectively. Using revision for any cause as the end, survivorship of the hemispherical cups at 7.6 years was 80.66% while the peripherally expanded cups at 8.2 years was 98.15%. Conclusions. In our case-series, a peripherally expanded cup has shown a better mid-term radiological and clinical result, with a lower rate of re-revision surgery, when compared to a hemispherical cup

Introduction. Impaction bone grafting for reconstitution of acetabular bone stock in revision hip surgery has been used for nearly 30 years. We report results in a group of patients upon whom data has been collected prospectively with a minimum ten year follow-up. Material and Methods. Acetabular impaction grafting was performed in 305 hips in 293 patients revised for aseptic loosening between 1995 and 2001. In this series 33% of cases required stainless steel meshes to reconstruct medial wall or rim defects prior to graft impaction. These meshes were the the only implants used for this purpose in this series. All Paprosky grades of defect were included. Clinical and radiographic outcomes were collected in surviving patients at a minimum of 10 years following the index operation; mean follow-up was 12.4 years (SD 1.5; range 10.0–16.0). Results. Kaplan-Meier survivorship with revision for aseptic loosening as the endpoint was 86% (95% CI 81.1 to 90.9%). Clinical scores for pain relief and function remained satisfactory (mean OHS 33.3, Harris hip score for pain 36.7, Harris hip score for function 27.3). Of the 125 hips still available with at least 10 years of radiographic follow-up, 97 appeared stable and 28 were judged to be radiologically loose; however, there was no significant difference in the pain and function scores between the two groups. The overall complication rate was 11.5%, including 1% peri-operative death, 3.3% dislocation and 0.3% deep infection. Discussion. This is the largest series of medium- to long-term results of acetabular impaction bone grafting with a cemented cup for revision hip arthroplasty reported to date. The technique is particularly successful when used for Paprosky grade 1 and 2 deficiencies; grade 3 deficiencies may be better managed with a different method for reconstructing larger defects e.g. trabecular metal augments. Conclusion. This series shows good long-term results for impaction bone grafting of acetabular deficiencies in revision hip surgery, with survivorship of 86% for aseptic loosening at 13.5 years and satisfactory clinical outcomes

Additive manufacturing has enabled a radical change in how surgeons reconstruct massive acetabular defects in revision hip surgery. We report on the early clinical and radiological results from our methods for surgical planning, design, and implantation of 3D printed trabecular titanium implants in a cohort of patients with large unclassifiable pelvic defects. We set up a prospective investigation involving 7 consecutive patients. Inclusion criteria was the following: 1) A history of previous total hip replacement; and 2) Current imaging showing at least a Paprosky 3B defect. Planned acetabular inclination and version was 40° and 20° respectively. Post operatively all patients had a CT scan which was analysed with software to determine component position and compared to planned. Outpatient review was done at 2 weeks (For wound), 6 weeks (for weight bearing and fixation) and 52 weeks (for fixation and infection) post-operative. The median age at surgery was: 65 years (40–78). The median bone defect volume was 140cm. 3. Median surgery length was 5.2 hours (3–6.25). Median blood loss was 1300mL (450– 2000). Radiologically, components were stable and no screw breakages were identified. Achieved inclination was 41.0° (29.0–55.6) and achieved version was 15.8° (3.8–43.6). Median Oxford Hip score improved from 9 (2–44) to 25 (18–32). We have demonstrated a new series of pre, intra and post-operative methods for reconstruction of unclassifiable acetabular bony defects. Initial clinical and radiological results are excellent considering the severity of the bony defects. We recommend the use of our or similar methods when trying to reconstruct these defects

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

Acetabular impaction grafting (AIG) for the reconstruction of acetabular defects in total hip arthroplasty has the potential to recreate anatomy whilst also allowing the restoration of bone stock. The incorporation of impacted, morcellised bone graft has been demonstrated in histological studies and is a well established technique in revision hip surgery where there is loss of bone stock. We have studied our results of fullAIG when used in primary total hip arthroplasty, with particular emphasis on the results of AIG in cavitary and segmental defects. Between 1995 and 2003, 129 cemented primary THAs were performed using full acetabular impaction grafting to reconstruct acetabular deficiencies. These were classified as cavitary in 74 and segmental in 55 hips. Eighty-one patients were reviewed at mean 9.1 (6.2–14.3) years post-operatively. There were seven acetabular component revisions due to aseptic loosening, and a further 11 cases that had migrated »5 mm or tilted »5° on radiological review — ten of which reported no symptoms. Kaplan–Meier analysis of revisions for aseptic loosening demonstrates 100% survival at nine years for cavitary defects compared to 82.6% for segmental defects. Our results suggest that the medium-term survival of this technique is excellent when used for purely cavitary defects but less predictable when used with large rim meshes in segmental defects

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

Revision hip surgery is about simplification. As such, a single revision stem makes sense. The most important advantage of Tapered Conical Revision (TCR) stem is versatility - managing ALL levels of femoral bone loss (present before revision or created during revision). The surgeon and team quickly gain familiarity with the techniques and instruments for preparation and implantation and subsequently master its use for a variety of situations. This ability to use the stem in a variety of bone loss situations eliminates intraoperative shuffle (changes in the surgical plan resulting in more instruments being opened), as bone loss can be significantly underestimated preoperatively or may change intraoperatively. Furthermore, distal fixation can be obtained simply and reliably. Paprosky 1 femoral defects can be treated with a primary-type stem for the most part. All other femoral defects can be treated with a TCR stem. Fully porous coated stems also work for many revisions but why have two different revision stem choices available when the TCR stems work for ALL defects?. TCR stems can be modular or monolithic but there are common keys to success. First and foremost, proper exposure is essential to assess bone defects and to safely prepare the femur. An extended osteotomy is often useful. Reaming distally to prepare a cone for fixation of the conical stem is a critical requirement to prevent subsidence (true for all revision stems). Restoration of hip mechanics (offset, leg length and stability) is fundamental to the clinical result. TCR stems have instrumentation and techniques that ensure this happens, since all this occurs AFTER distal stability is achieved. Modular TCR versions have some advantages. The proximal body size and length can be adjusted AFTER stem insertion if the stem goes deeper than the trial. Any proximal/distal bone size mismatch can be accommodated. If the surgeon believes that proximal bone ingrowth is important to facilitate proximal bone remodeling, modular TCR stems can more easily accomplish this. Further, proximal bone contact and osseointegration will protect the modular junction from stress and possible risk of fracture. Monolithic TCR versions also have some advantages. Modular junction mechanical integrity cannot accommodate smaller bone sizes. Shorter stem lengths are not available in modular versions, and shorter TCR stems are an option in many revision cases. The possibility of modular junction corrosion is eliminated and fracture of the stem at that junction, of course, is not possible. The monolithic stem option is less expensive as well. Consider Modular TCR stems in your learning curve, if you feel proximal bone osseointegration is important and if proximal/distal size mismatch is present. Consider Monolithic TCR stems after your learning curve to reduce cost, when a short stem works, and if a small stem is needed. Both Modular and Monolithic stems can be used for ALL cases with equal quality of result

Reoperation on the acetabular side of the total hip arthroplasty construct because of acetabular liner wear with or without extensive osteolysis is the most common reoperation performed in revision hip surgery today. The options of revision of the component or component retention, liner exchange (cemented or direct reinsertion) and bone grafting represent a classic surgeon dilemma of choices and compromises. CT scanning is helpful in determining the size and location of osteolytic lesions. My preference is to retain the existing shell when possible especially when there are large osteolytic lesions but where structural support is maintained. The advantages of complete revision are easy access to lytic lesions, ability to change component position and the ability to use contemporary designs with optimal bearing surfaces (for wear and dislocation prevention). The disadvantage is bone disruption including pelvic discontinuity with component removal (less so with Explant Systems) and difficult reconstructions due to excessive bone loss from the osteolytic defects (sometimes requiring cup cages). The advantage of component retention is that structural integrity of the pelvis is maintained and in general, a higher quality polyethylene is utilised. For large lesions I use windows to debride and bone graft the lesions. If the locking mechanism is inadequate, cementing a liner, including a constrained liner in some cases, that has been scored in a spider web configuration provides durable results at 5-year follow-up. The downside to liner exchange is potential instability. We immobilise all liner exchange patients postoperatively

Background. Cup migration and bone graft resorption are some of the limitations after acetabular impaction bone grafting (IBG) technique in revision hip surgery when used for large segmental defects. We asked whether the use of a metallic mesh may decrease the appearance of this complication. We compared the appearance of loosening in patients with a bone defect 3A or 3B according to Paprosky. Materials and Methods. We assessed 204 hips operated with IBG and a cemented cup according to Slooff et al between 1997 and 2004. There were 100 hips with a preoperative bone defect of 3A and 104 with a 3B. We used 142 medial and/or rim metallic meshes for uncontained defects. The mean follow-up for unrevised cups was 10.4 years. We detemined postoperative radiological cup position and acetabular reconstruction of the hip center according to Ranawat in both groups. We assessed the appearance of radiological loosening and resorption of the graft. Results. Postoperative cup position improved in both groups (p<0.001 for all parametres). Distance to the approximate center of the hip decreased from 23.5 to 8.5 mm. 8 hips showed radiological loosening in group with a bone defect 3A and 16 in group 3B. The survival rate for loosening at 15 years was for 83.2 +12% for group 3A and 72.5 + 12% for group 3B (Mantel-Cox, p=0.04). The survival rate when using mesh or not at 15 years for loosening was: No Mesh 89.1 + 14%, Medial mesh 84.9 + 12%, Rim 79.6 + 12%, Medial and Rim 53.9 + 22 % (Mantel Cox, p=0.008). Patients with a bone defect 3B and a rim metallic mesh had a higher risk for loosening (p=0.047; Hazard Ratio: 2.36, Confidence Interval 95% (CI) 1.01–5.5, and, p=0.026; HR: 3.7, CI 95%: 1.13–12.4, respectively). Conclusions. IBG provides an improvement of the reconstruction of the rotation of the hip centre in acetabular revision surgery. Although results are good for contained or medial large defects, hips with a rim large segmental defect may need other options for reconstruction of these challenged surgeries

In patients with conventional metal-on-Polyethylene (MoP) hip replacements, osteolysis can occur in response to wear debris. During revision hip surgery, surgeons usually remove the source of osteolysis (polyethylene) but cannot always remove all of the inflammatory granulomatous tissues in the joint. We used a human/rat xenograft model to evaluate the effects of polyethylene granuloma tissues on bone healing. Human osteoarthritic and periprosthetic tissues collected during primary and revision hip arthroplasty surgeries were transplanted into the distal femora of athymic (nude) rats. The tissues were assessed before and after implantation and the bone response to the tissues was evaluated after 1 week and 3 weeks using micro-computed tomography, histology, and immunohistochemistry. After 3 weeks, the majority (70%) of defects filled with osteoarthritic tissues healed, while only 21% of defects with polyethylene granuloma tissues healed. Polyethylene granuloma tissues in trabecular bone defects inhibited bone healing. Surgeons should remove polyethylene granuloma tissues during revision surgery when possible, since these tissues may slow bone healing around a newly implanted prosthesis. This model provides a method for delivering clinically relevant sized particles into an in vivo model for investigation

Introduction. Recurrent dislocation after hip arthroplasty is a difficult problem. The purpose of the present study was to evaluate the results with the use of a constrained cup for treatment for instability after hip arthroplasty. Materials/Method. A prospective database of 30 patients who underwent revision hip surgery for dislocation of hip arthroplasty was kept with the surgeries taking place between Nov 2005 to Feb 2010. Results. The mean age of the cohort was 76.5 years (53–93 years) with 17 female and 13 male patients. The gap between primary hip surgery and constrained cup ranged from 1 week to 21 years. The follow-up ranged from 8 months to 62 months with an average of 31 months. The primary surgery was a total hip arthroplasty in 27 patients and cemented hemiarthroplasty in 3 patients. Femoral component revision was done in 6 patients. At latest clinical follow-up 16 patients were mobilising unaided and 6 needed some support. Post-operative complications included capture cup pullout from the sidewall of the pelvis in the first week post op. Infection complicated 2 patients with one patient ending up having a girdlestone type excision and the other treated with antibiotic suppression. One patient had post op problems of wound dehiscence treated with VAC therapy. Conclusion. This is a useful technique for a difficult management problem

Purpose of Study. To assess the results of Revision Hip Surgery in which a less invasive technique was utilized in situations where a number of different options was available. Method. The authors rely on an experience of 3,445 hip arthroplasties by a single surgeon over a period of 20 years, of which approximately 20% were revision cases. Of these 617 cases, we report on 175 in which a minimally invasive option was taken. This does not apply to the skin incision, as all cases were adequately exposed. We have adopted this term to describe cases in which a surgical options was taken that resulted in the least morbidity and the shortest surgical time. We postulated that would lead to the best outcomes with the least complications. Acetabular revisions: 1) Isolated polyethylene exchange. 2) Liner revision with cement technique in cases of cup malposition or poor locking mechanism. 3) Revision of cup with a primary prosthesis with significant medial bone loss. Stem revisions: 1) Cement on cement technique. 2) Strut graft and primary stem. Results. We found a very low complication rate utilizing these methods: Fatal pulmonary emboli: 0 Sepsis: 2 Dislocations 3 Repeat revisions 3. Conclusion. Revision surgery offers many challenges that tend to be compounded with successive operations. We believe that good results can be achieved when a philosophy of minimally invasive surgery is adopted. NO DISCLOSURES

The advantages of modularity in both primary and revision hip surgery are well documented, and have been at the heart of innovation in hip implant design over the last two decades. There have been significant developments in modularity proximally at the head-neck junction, more distally with modular necks and at mid-stem level, notable for complex revisions. Modularity allows us to address version, length and offset issues and to restore optimal hip biomechanics. There are, however, increasing clinical concerns associated with the failure of taper junctions. The use of large femoral heads and modular stems are now considered major risk factors for taper corrosion. Recent studies have shown an 8–9% early revision rate of one modular neck design due to pain and adverse local tissue reaction. I will summarise our laboratory and retrieval data on taper design and tribology in order to put in perspective the clinical use of modularity in hip arthroplasty. Modular junctions rely on a frictional interlock. The engagement obtained and resulting micromotion is strongly influenced by taper size, taper length/engagement, material, surface finish, neck length and offset. In our quest for thinner femoral necks, greater offsets and bigger femoral heads, we have inadvertently created an environment that can generate fretting corrosion at modular junctions and leads to premature implant failure. Our work demonstrates that increasing torque and bending moment leads to increased susceptibility to fretting corrosion at the modular taper interface of total hip replacements. This is particularly relevant with the increasing use of larger diameter femoral heads that produce higher torques. It also identifies surface area and surface finish as important factors in wear and corrosion at the modular interface of total hip replacements. Critically, the combination of these factors can lead to extensive corrosion at the interface. Surgical technique is also important. Higher impaction loads on clean, dry surfaces result in greater contact length and extraction forces, which may influence micromotion. It is critical in future that all innovation is introduced in a systematic gradual fashion so that we do not fall into similar traps again. The unintended consequences of minor changes in design may have a massive effect on outcomes. Our findings suggest that it may be possible to continue to employ the advantages of modularity in hip surgery whilst avoiding some of the pitfalls that have led to the failure of some modular systems. Understanding the key design and surgical factors that drive the performance of taper junctions is vital for the surgical community. There is a body of knowledge that supports appropriate taper use / modularity to help surgeons deal with complex situations. We must be careful not throw the baby out with the bathwater

Introduction. We present the outcome of 297 acetabular revisions using bone grafting and cemented acetabular components in 297 patients, with a mean follow-up of 8 years 3 months (5–20 years). Methods. All patients underwent acetabular revision with allograft bone grafting and insertion of cemented acetabular components. Of the 297 patients, 134 patients (45%) were male and 163 (55%) were female. The mean age of undergoing revision surgery with bone grafting was 60 years (25–87 years). The mean weight at revision surgery was 71.9 kg (40–128 kg). Post-operatively, all patients were reviewed regularly in out-patients, where they were examined clinically for any complications and their radiographs were examined for evidence of graft union, radiological lucency and cup migration. Results. Post-operatively, 61 patients suffered from early complications, which were defined as complications within one year of surgery. These included 15 dislocations (5%), 12 trochanteric non-unions (4%), 2 deep infection (0.7%), and 32 medical complications (11%). Thirty six patients (12%) have subsequently undergone re-revision surgery. Twenty four re-revisions were performed due to loose socket (8%), 12 for loose stem (4%), 3 for deep infection (1%), 2 for dislocation (0.7%) and 1 for fractured stem (0.4%). In all the cases of loose socket, radiolucent lines at the bone cement interface were noted. Discussion. Reconstruction of the acetabulum during revision hip surgery using allograft and cemented cup is an effective technique with good short term results