Purpose of the study: The objective of this retrospective analysis was to examine the functional and radiographic results of 33 resvisions for femoral implants using a long locked stem inserted without cement and coated with hydroxyapatite.

Material and methods: Mean follow-up was two years for 33 patient who underwent revison total hip arthroplasty (rTHA) with implantation of a press-fit long locked hydroxyapatite coated femoral stem (Aura or Linea) between 2000 and 2004. The explanted prosthesis was cemented in 23 cases. The reason for revision was femoral loosentng for 60%, femoral fracture for five pateints, and infection for two. According to the SOFCOT 1999 criteria, ten patients had bone defects score grade III or IV. Femorotomy was performed in 21 cases. Patients were reviewed clinically and radiologically. Function was assessed with the Postel-Merle-d’Aubligné (PMA) score and radiographic analysis determined the quality of osteointegration of the implants and the restitution of bone stock.

Results: There were six early complications (one death, one disloction with sciatic paralysis), and six late complications, mainly related to defective locking. The PMA score was less than 3 for only three patients. Twenty-six patients were satisfied or very satisfied and seven patients reported thigh pain which was generally moderate. The locking was released for five prostheses because of failure or pain (relief observed in three cases). Migration was noted in three cases, illustrating their non-integration. For 15 patients, corticalisation around the lower part of the prosthesis suggested implant mobility. This image was observed in all patients who complained of thigh pain (p=0.057). There was a significant increase in the cortical index, reflecting progression of the bone stock favoring the internal cortex.

Conclusion: This type of implant has provided a solution for the difficult problems of explantation and reimplantation of THA. These prostheses provide satisfactory short-term results and a significant improvement in bone stock. There remains the problem of osteointegration of certain implants. Technical factors can contribute to improved clinical results.

Aim: The objective of this study was to compare the initial stability of an uncemented curved long stem femoral component (ABR, Zimmer, Warsaw Indiana) implanted using conventional broaching to an uncemented ABR implanted as a revision using morselized compacted allograft to fill a circumferential proximal bone defect.

Materials and Methods: Primary: Eight fresh frozen human femurs were implanted with correctly sized ABR stems without cement using standard surgical instruments and 1mm distal overreaming. The implant was loaded cyclically at 3 hz on a MTS servohdraulic materials test frame in a direction representing the peak force of the stance phase of the gait (2.5 X body weight). A 3-dimensional motion measurement device with six linear variable transformers measure the relative motion between the bone and the prosthesis with an accuracy of 0.5μm. The contruct was loaded in ten cycle increments until the component was seated and then recoverable motion was recorded over a further ten loading cycles. Revision: In the revision case bone loss was modelled by removing all the cancellous bone from the proximal femur with 1mm distal overreaming. Morselized bone graft was impacted into the defect using specially prepared smooth tamps shaped to the geometry of the ABR stem. The original prosthesis was then reimplanted without the use of cement. The seating and testing cycles were repeated. Primary and revision vectors were compared using a paired students t – test.

Results: There was no statistically significant difference in the magnitude of the resultant vector of the 3 translational components of the micro motion between the two methods of implantation (p=0.19).

Conclusions: Initial stability of a cementless femoral implant is a requirement for bone ingrowth. The use of compacted morsellized allograft in a revision Total Hip Arthroplasty with a proximal circumferential defect can provide a stable bed for the implantation of an uncemented femoral component. The revised implant using the compacted allograft method was initially as stable as the primary implantation.

This technique would be particularly applicable when the surgeon would like to avoid the use of cement in a revision setting. The use of this method for uncemented revision Total Hip Arthroplasty should be studied further in a clinical setting before it is advocated for widespread use.

Purpose of the study: The PFM-R (Zimmer) prosthesis is a straight modular stem made of sanded titanium designed to favour spontaneous bone reconstruction. The purpose of this work was to analyse the clinical and radiographic results of this implant.

Material and methods: This was a consecutive prospective series of 154 patients who underwent surgery from 1998 to 2007 (15 first-intention prostheses and 139 revisions for severe loosening [Paprosky stages 3 and 4]). Revision included a clinical evaluation (PMA score) and radiographic assessment (migration, bone regeneration, stress shielding, osteointegration, Le Béguec score) as well as a survival analysis.

Results: At mean 4.6 years follow-up (1–10 years), three patients had died, two were lost to follow-up and 18 implants were removed, 11 for infection, six for migration and one for defective technique. The PMA score improved from 8 (0–16) to 15.8 (5–18). Mean pivot impaction was 4 mm (0–50), statistically dependent on initial bone stock, form of the isthma, the corticomedullary index in the implantation zone, length of anchor, and time to weight bearing, but not femorotomy nor zone of primary stability. Bone stock was good in 73% at poor in 27% (15 stress shielding, nine infectious osteolysis, 16 absence of bone regeneration). Stress shielding was related to length and diameter of the implanted pivot (p< 0.05). Bone regrowth was statistically dependent on the number of prior operations, type of stem explanted (cemented), initial bone stock, form of the isthma and quality of the surgical reconstruction. The implant was osteointegrated in 128 cases (86%). The analysis of the prosthetic anchoring showed that primary stability was mainly diaphyseal (90%) then secondarily global (83%). Osteointegration depended statistically on the number of prior operations, initial bone stock, form of the isthma and bone regrowth, but not femorotomy. The overall Le Béquec score reached 14.7 (2–20) at last follow-up.

Discussion: The PFM-R enabled bone regeneration and osteointegration in the majority of patients. The quality of the femoral reconstruction around the implant appears to be fundamental. Massive stems should be avoided as they lead to stress shielding. The limits for use of this implant are osteopenia and absence of an isthma.

Purpose of the study: The revision modular femoral prosthesis (PFM-R) (Centerpulse) uses a cone-shaped straight femoral stem with winglets for press-fit revision fixation in the femoral shaft. The risk of secondary migration further into the shaft is well known. The purpose of this paper was to assess the degree of PFM-R stem migration and to search for predictive factors in order to better ascertain the limits of this type of revision anchorage in the femoral shaft.

Material and methods: Fifty-three files (48 patients) were reviewed retrospectively at minimum none months follow-up. Mean patient age was 56.6 years. Revision was required for loosening (SOFCOT classification): grade 1 (n=5), grade 2 (n=8), grade 3 (n=17), grade 4 (n=10). For 13 hips, the implant to be replaced was not cemented (monobloc stem, infection), or a first-intention PFM-R.

Results: Mean migration was 4.1 mm (0–17 mm), less than 5 mm in 73.5% of cases. There was no correlation between migration and SOFCOT grade. Conversely, there was a significant difference in migration between the grade 1 and grade 3B and between Paprosky grade 1 and 4 (p=0.05). The degree of migration was correlated with the length of the persistent isthma (p< 0.0001), with the morphology of the isthma [conic/inverted conic (p< 0.01), conic/cylindric (p< 0.051)], with the cortical index (p=0.06), the length of the anchor wings (p=0.051), but not with the length of the femorotomy bridge. The length of the wing anchorage was correlated with the length of the persistent isthma (p=0.002) and with the morphology of the isthma [(conic/inverted conic p=0.02), cylindric/inverted conic (p=0.02)], but did not increase significantly with bridging length. There was a trend towards migration in osteoporotic bone (p=0.07).

Discussion and conclusion: Use of a straight stem for anchorage in the femur is associated with secondary migration which depends on the quality of the bone in the anchorage zone and the extent of the press-fit. The persistence of a cone-shaped or cylindrical isthma measuring greater than 4 cm associated with a cortical index greater than 45% and a long wing anchorage can provide excellent primary stability. It would be useless to use long stems since they do not increase the quality of anchorage. The absence of an isthma and the presence of osteoporosis are limitations for this concept.

Aim. Infection rates after revision THA vary widely, up to 12%. In countries that use antibiotic-loaded cemented stems in combination with perioperative IV antibiotics, infection rates in registry studies are lower. In many countries, however, cementless revision implants are preferred. Our aim was to apply an antibiotic-loaded calcium sulfate coating to cementless revision stems to reduce periprosthetic joint infection (PJI). This study sought to answer two questions: 1) Does the coating of cementless revision stems with calcium sulfate inhibit osteointegration in THA? 2) Does the antibiotic-loaded calcium sulfate coating of revision stems reduce the incidence of PJI?. Method. From Dec. 2010 to Dec. 2015, 111 consecutive revision femoral stems were coated with commercially pure calcium sulfate. 10cc of calcium sulfate was mixed with 1g of vancomycin powder and 240mg of tobramycin liquid and applied to the stem in a semi-firm liquid state immediately prior to stem insertion. The results are compared to a designated control cohort (N=104) performed across the previous 5 years. The surgical methods were comparable, but for the stem coating. All patients were staged preoperatively using the Musculoskeletal Infection Society Staging System and followed for at least 1 year. Results. In the study group of coated stems, there were 46 A hosts, 56 B hosts, and 9 C hosts. In the control group, there were 45 A hosts, 52 B hosts, and 7 C hosts. Both cohorts had 0 cases of aseptic loosening. The overall rate of PJI in the study cohort was 2.7%. Of the 111 revisions, 69 were aseptic (PJI=1.4%) and 42 were second stage revisions for infection (PJI=4.8%). PJI occurred in 2.2% of A hosts, 1.8% of B hosts, and 11.1% of C hosts. In the control cohort, the overall rate of PJI was 7.7%. Of the 104 revisions, 74 were aseptic (PJI=1.4%) and 30 were second stage revisions for infection (PJI=23.3%). PJI occurred in 6.7% of A hosts, 5.8% of B hosts, and 28.6% of C hosts. The results show a reduction in PJI from 7.7% in the control group to 2.7% in the study group and were found to be statistically significant at p-value<0.1 (p=0.09). Conclusions. The application of antibiotic-loaded calcium sulfate to cementless revision femoral stems does reduce PJI. Importantly, this coating did not inhibit osteointegration of the femoral stem. The reduced infection rate in this study supports the concept that bacteria frequently contaminate and reside within the femoral canal

Modularity in femoral revision stems was developed to reduce subsidence, leg length discrepancy and dislocation experienced in revision surgery. The Wagner SL Revision Stem (Zimmer, Warsaw, IN) has been known for excellent bony fixation and proximal bony regeneration, but the third-generation proportional neck offset and 135° neck-shaft angle has an unknown track record. Our aim is to study the effect of these design modifications on stem subsidence, dislocation rate and stem survival. We reviewed 76 consecutive femoral revisions (70 patients; 50 M: 20 W; 67.7 yo [range; 37.7 – 86.6 yo]) with the Wagner SL implanted at our institution (2004–2012). No patient was lost to follow-up, but nine had died, and one patient was excluded for a Paprosky type I femoral bone defect. This leaves us 66 hips (60 patients) at 2 to 9.5 years of follow-up (mean 55 months; range, 24–114 months). Indications for revisions included aseptic stem loosening (62.1%), infection (13.6%), acetabular loosening (12.1%), recurrent dislocation (4.5%), periprosthetic (4.5%) and stem fracture (1.5%), and chondrolysis (1.5%). Patients were actively followed up at regular intervals to ascertain revision status and outcome measures including the Merle d'Aubigné (n=53), WOMAC questionnaires (n=59) and radiographs (n=66). Radiographs were evaluated for stem subsidence (mm). One of the surviving 66 stems was revised for recurrent deep infection (1.5%). No patient underwent revision of the femoral stem for aseptic loosening or subsidence. The mean preoperative WOMAC scores (P: 12.8; S: 5.6; F: 51.8) had improved significantly at follow-up (P: 9.7;, S: 4.3; F: 37.6) (p<0.05). The mean Merle D'Aubigné score went from a pre-op of 8.2 (SD: 2.8; range 1 to 14) to a mean of 15.3 (SD: 2.6; range 7 to 18) (p<0,05) at the latest follow-up. During the follow-up period, 3 hips dislocated (4.5%). Each event happened prior to six months after surgery. Only one of these cases dislocated twice. Closed reduction was performed in all cases. None required revision surgery subsequently, and they all remained stable. The stem survivorship is 98.4% at 5 years (0.95 CI: 93–100) and 97.4% at 7.5 years (0.95 CI: 88.9–100). Stem subsidence of 0 to 5 mm was considered as not clinically significant (n=20; 30%). Stem subsidence of 5 to 10 mm occurred in 5 hips (7.6%)and stem subsidence greater than 10 mm only occurred in one hips (1.5%). The third generation Wagner SL conical revision femoral stem has a lower rate of complication than its preceding generations, and is comparable to modular stems performance reported in current literature. These results motivate the authors to continue using monoblock conical revision femoral stems

The well-fixed femoral stem can be challenging to remove. Removal of an extensively osteointegrated cementless stem requires disruption of the entire implant-bone interface while a well-fixed cemented stem requires complete removal of all adherent cement from the underlying cortical bone in both the metaphysis and diaphysis of the femur. In these situations, access to those areas of the femur distal to the metaphyseal flare that are beyond the reach of osteotomes and high speed burrs is necessary. This typically requires use of an extended femoral osteotomy (ETO). The ETO should be carefully planned so that it extends distal enough to allow for access to the end of the stem or cement column and still allow for stable fixation of a new implant. Too short of an ETO increases the risk of femoral perforation by straight burrs, trephines or cement removal instruments that cannot negotiate the bowed femoral canal to access the end of the cement column or end of the stem without risk of perforation. The ETO should also be long enough to allow for fixation with at least 2 cerclage cables. An ETO that is too distal makes implant and cement removal easier, but may not allow for sufficient fixation of a new revision femoral stem. After insertion of the revision stem, the osteotomy is reduced back around the stem and secured in place with cerclage cables

Purpose: Bone remodelling and osteolysis around total hip arthroplasty (THA) is a highly debated subject in the medical literature. Such bone behaviour is poorly understood around femoral stems used in revision THA. The main problem is to obtain an objective assessment of bone remodelling and bone reconstruction over time, reconstruction techniques being very variable. Conventional radiology is insufficient, but dual energy x-ray absorptiometry (DEXA) provides a means of following changes in the bone around first intention femoral stems. Material and methods: We studied bone behaviour around revision femoral stems using the non-cemented “P.P. system”. This type of femoral stem is implanted after trochanter osteotomy to facilitate access and stimulate reconstruction. The series included 31 patients who underwent revision total hip arthroplasty. Follow-up examinations included standard radiographs and DEXA of the operated hips, the contralateral hip and the lumbar spine. Periprosthetic zones defined by Grüen were compared with the same zones in the contra-lateral femur. Mean follow-up was six years. Results: The standard radiographs did not demonstrate any significant change in periprosthetic cortical thickness. The DEXA demonstrated a significant an average 19.97% reduction in bone density in zones 2, 3, 4, 5 and 6. There was no significant difference in zone 7 and an increase in zone 1 (torchanter osteotomy). These figures are to be compared with the variable thickness observed for first intention pros-theses even shortly after implantation. Discussion: Our results are the first to our knowledge demonstrating the behaviour of bone around revision femoral stems. Conclusion: Digastric trochanterotomy appears to be an effective means of stimulating reconstruction of the proximal femur. At equivalent follow-up, the quadrangular section of the revision P.P. stem is more favourable in terms of bone loss compared with first intention stems

Femoral stem fracture occurred in five (2%) of 283 revision hip arthroplasties when extensively coated, distal fixation femoral implants were used. Common features were complex revisions, high body mass index, poor proximal support, smaller stems (< 13.5 mm) and use of an extended trochanteric osteotomy. Use of strut allografts can reduce femoral stem stresses. The purpose of this study was to analyze the surgical factors associated with fracture of cementless distal fixation revision femoral stems and supplement this analysis with a finite element analysis. Data from our institutional joint replacement database identified five (2%) fractured femoral stems (three Solution, two Echelon) in a cohort of two hundred and eighty-three cementless distal fixation femoral stems (one hundred and eighty-two Solution, one hundred and one Echelon) followed over two years. Patient, surgical and implant factors were compared between the fractured and not fractured stems. Finite element analysis was performed on two fractured stem cases to better understand the fracture mechanism. Common clinical features of the five fractured stems were complex revisions, high patient body mass index, poor proximal bone support, smaller stems (< 13.5 mm) and use of an extended trochanteric osteotomy (ETO) (3/5). Fatigue failure was the mode failure in all cases. Finite element analysis confirmed that the location of highest stem stress was near the location of the stem fracture and that use of a strut graft over an extended trochanteric osteotomy in patients lacking proximal femoral cortical support decreased the stem stresses by 48%. Use of cementless distal fixation revision femoral stems is accompanied by a 2% risk of stem fracture in the face of proximal femoral support of the stem and/or use of a stem with a diameter less than 13.5 mm. When an extended trochanteric osteotomy is used, the stem fracture rate increased to 4%. Use of a strut allograft in conjunction with the ETO can reduce stem stresses by 48% and the risk of stem fracture. Funding: Research support from J& J DePuy and Smith & Nephew

Aims

United Classification System (UCS) B2 and B3 periprosthetic fractures in total hip arthroplasties (THAs) have been commonly managed with modular tapered stems. No study has evaluated the use of monoblock fluted tapered titanium stems for this indication. This study aimed to evaluate the effects of a monoblock stems on implant survivorship, postoperative outcomes, radiological outcomes, and osseointegration following treatment of THA UCS B2 and B3 periprosthetic fractures.

Introduction. The risk of hip dislocation after revision total hip arthroplasty is up to 20% following surgery for periprosthetic fractures. A technique was developed by the senior authors, involving a transtrochanteric osteotomy and superior capsulotomy to attempt to minimise this risk(1). Methods. This prospective study examines a cohort of 40 patients undergoing this novel technique, which involves extending the fracture proximally to the tip of the greater trochanter. This is then extended into the soft tissues in the mid lateral plane as a split of the glutei and a minimally superior capsulotomy (preserving the anterior and posterior capsule). This allows for revision of the femoral component, and retention of the socket and liner. The outcomes of interest to the authors were dislocation rates, clinical outcome measured using the Oxford hip score. These were assessed along with X-ray imaging at 1, 2 and 5-year intervals to confirm fracture union and measure stem subsidence. Results. Patients averaged 80 years of age, with a higher ratio of females (3:2). There were no cases of hip joint dislocations. Two patients (5%) underwent subsequent revision hip arthroplasty within the first 12 months of initial revision. Femoral stem subsidence at 1 year averaged 5.9 mm. All fractures showed radiological evidence of union. The Oxford hip score was fair, averaging 31/48 by 1 year post-op, and then plateaued at 32.8/48 at 2 years post-op. Conclusion. 5 year follow-up of this novel operative technique in revision arthroplasty of Vancouver B periprosthetic hip fractures has confirmed the benefits, with no cases of hip dislocation, along with overall satisfactory patient clinical outcomes

Aims

Large acetabular bone defects encountered in revision total hip arthroplasty (THA) are challenging to restore. Metal constructs for structural support are combined with bone graft materials for restoration. Autograft is restricted due to limited volume, and allogenic grafts have downsides including cost, availability, and operative processing. Bone graft substitutes (BGS) are an attractive alternative if they can demonstrate positive remodelling. One potential product is a biphasic injectable mixture (Cerament) that combines a fast-resorbing material (calcium sulphate) with the highly osteoconductive material hydroxyapatite. This study reviews the application of this biomaterial in large acetabular defects.

It's easy to say that hip resurfacing is a failed technology. Journals and lay press are replete with negative reports concerning metal-on-metal bearing failures, destructive pseudotumors, withdrawals and recalls. Reviews of national joint registries show revision risks with hip resurfacing exceeding those of traditional total hip replacement, and metal bearings fare worst among all bearing couples. Yet, that misses the point. Modern hip resurfacing was never meant to replace total hip replacement (THR). It was intended to preserve bone in young patients who would be expected to need multiple revisions due to their youth and high-demand activities. The stated goal of the developers of the Birmingham Hip Resurfacing (BHR) was to delay THR by 10 years. In the two decades that followed the release of BHR, this goal has been met and exceeded. Much has been learned about indications, patient selection, and surgical technique. We now know that this highly specialised, challenging procedure is best indicated in the young, active male with osteoarthritis, as a complementary, not competitive procedure, to THR. Resurfacing has many advantages. First and foremost, it saves bone, on the day of surgery, and over the next several years by preventing stress shielding. Dislocations are very rare. Leg length discrepancy and changes in offset are avoided. Post-operative activity, including heavy manual labor and contact sports, is unrestricted. More normal loading of the femur and joint stability has allowed professional athletes to regain their careers. Femoral side revisions, if necessary, are simple total hips, and dual mobility constructs allow one to keep the socket. Adverse reactions to metal debris (ARMD), including pseudotumors, have generated great concern. Initially described only in women, it was unclear whether the etiology was allergy, toxicity, or inflammation. A better understanding of the wear properties of the bearing, and its relation to size, anteversion, hip dysplasia and metallurgy, along with retrieval analysis, allow us to conclude that it is excessive wear due to edge loading which is the fundamental mechanism for the vast majority of ARMD. Thus, patient selection, implant selection and surgical technique, the orthopaedic triad, are paramount. What has been most impressive are the truly exceptional results in young, active men. The worst candidates for THR turn out to be the best candidates for resurfacing. The ability to return to full, unrestricted activity is just as important to these patients as the spectacular survivorship in centers specializing in resurfacing. If they are unlucky and face a revision, they are not facing the life-changing outcomes of a long revision femoral stem. So if the best indication for hip resurfacing is the young, active male, let's look at the results of resurfacing these patients in centers with high volumes, using devices with a good track record, such as BHR. Several centers around the world report 10–18 year success rates of BHR in males under 50 at 98–100%. Return to athletics is routinely achieved, and even professional athletes have regained their careers. Hip resurfacing doesn't have to be better than THR to be popular among patients. Just the idea of saving all that bone makes it attractive. In the young active male, however, the results exceed those of THR, while leaving better revision options for the future. This justifies its continued use in this challenging patient population

Introduction. Cementless grit-blasted tapered-wedge titanium femoral stems are being used with increasing frequency in hip arthroplasty because of excellent long-term outcomes. However, periprosthetic femur fracture is a potentially worrisome phenomenon in these types of femoral stems. The aim of this study is to report the incidence of stem loosening in association with periprosthetic femur fractures following hip arthroplasty using cementless grit-blasted tapered-wedge stems. Materials & Methods. A total of 36 Vancouver Type B1 and B2 periprosthetic femur fractures following either hemiarthroplasty or total hip arthroplasty using cementless grit-blasted tapered-wedge titanium femoral stems (GB group) were identified from a retrospective review of the medical records at three participating academic institutions. The control group consisted of 21 Vancouver Type B1 and B2 periprosthetic femur fractures following either hemiarthroplasty or total hip arthroplasty using cementless proximal porous-coated femoral stems (PC group) at the same institutions during the same period of the study. All femoral stems included in this study had been a well-fixed state before the occurrence of periprosthetic femur fractures. All patients in both groups were treated surgically with either open reduction and internal fixation or femoral stem revision. Femoral stem stability was assessed by preoperative radiographs and was confirmed by intraoperative scrutinization. The incidence of stem loosening was compared between the groups. Results. There was no significant difference between the groups with respect to demographic data including age, gender, body mass index, primary diagnosis, Dorr types of proximal femur, and time to fracture. All fractures occurred from low-energy mechanisms. Mean age at the time of hip arthroplasty was 54.5 years in the GB group and 57.0 years in the PC group. Mean time interval between hip arthroplasty and periprosthetic fracture was 49.6 months in the GB group and 44.4 months in the PC group. At the time of the last follow-up, 29 (80.6%) of 36 fractures was Vancouver B2 in the GB group, whereas only 3 (14.3%) of 21 fractures was Vancouver B2 in the PC group (P <0.001). Conclusions. High incidence of stem loosening was developed in association with periprosthetic femur fractures in previously well-fixed cementless grit-blasted tapered-wedge femoral stems in our population. We believe that this is an underreported phenomenon of these types of stem design

The well-fixed cemented femoral stem and surrounding cement can be challenging to remove. Success requires evaluation of the quality of the cement mantle (interface lucency), position of the stem, extent of cement below the tip of the stem and skill with the specialised instruments and techniques needed to remove the stem and cement without perforating the femur. Smooth surfaced stems can usually be easily removed from the surrounding cement mantle with a variety of stem extractors that attach to the trunnion or an extraction hole on the implant. Roughened stems can be freed from the surrounding cement mantle with osteotomes or a narrow high speed burr and then extracted with the above instruments. Following this, the well-fixed cement mantle needs to be removed. Adequate exposure and visualization of the cement column is essential to remove the well-fixed cement without damage to the bone in the femur. This is important since fixation of a revision femoral component typically requires at least 4 cm of contact with supportive cortical bone, which can be difficult to obtain if the femur is perforated or if the isthmus damaged. Proximally, cement in the metaphyseal region can be thinned with a high speed burr, then split radially and removed piecemeal. It is essential to remember that both osteotomes and high speed burrs will cut thru bone easier than cement and use of these instruments poses a substantial risk of unintended bone removal and perforation of the femur if done improperly. These instruments should, as a result, be used under direct vision. Removal of more distal cement in the femur typically requires use of an extended femoral osteotomy (ETO) to allow for adequate access to the well-fixed cement in the bowed femoral canal. An ETO also facilitates more efficient removal of cement in the proximal femur. The ETO should be carefully planned so that it is distal enough to allow for access to the end of the cement column and still allow for stable fixation of a new implant. Too short of an ETO increases the risk of femoral perforation since the straight cement removal instruments cannot negotiate the bowed femoral canal to access the end of the cement column without risk of perforation. An ETO that is too distal makes cement removal easier, but may not allow for sufficient fixation of a new revision femoral stem. Cement below the level of the ETO cannot be directly visualised and specialised instruments are necessary to safely remove this distal cement. Radiofrequency cement removal devices use high frequency (ultrasonic) radio waves to melt the cement within the canal. Although cement removal with these devices is time consuming and tedious, they do substantially reduce the chances of femoral perforation. These devices can, however, generate considerable heat locally and can result in thermal injury to the bone and surrounding tissues. Once the distal end of the cement mantle is penetrated, backbiting or hooked curettes can be use to remove any remaining cement from within the canal. It is important that all cement be removed from the femur since reamers used for preparation of the distal canal will be deflected by any retained cement, which could result in eccentric reaming and inadvertent perforation of the femur and make fixation of a new implant very challenging. An intra-operative x-ray can be very helpful to insure that all cement has been removed before reaming is initiated. One should always plan for a possible femoral perforation and have cortical strut grafts and a stem available that will safely bypass the end of the cement column and the previous cement restrictor

The well-fixed cemented femoral stem and surrounding cement can be challenging to remove. Success requires evaluation of the quality of the cement mantle (interface lucency), position of the stem, extent of cement below the tip of the stem and skill with the specialised instruments and techniques needed to remove the stem and cement without perforating the femur. Smooth surfaced stems can usually be easily removed from the surrounding cement mantle with a variety of stem extractors that attach to the trunnion or an extraction hole on the implant. Roughened stems can be freed from the surrounding cement mantle with osteotomes or a narrow high speed burr and then extracted with the above instruments. Following this, the well fixed cement mantle needs to be removed. Adequate exposure and visualization of the cement column is essential to remove the well-fixed cement without damage to the bone in the femur. This is important since fixation of a revision femoral component typically requires at least 4cm of contact with supportive cortical bone, which can be difficult to obtain if the femur is perforated or if the isthmus damaged. Proximally, cement in the metaphyseal region can be thinned with a high speed burr, then split radially and removed piecemeal. It is essential to remember that both osteotomes and high speed burrs will cut thru bone easier than cement and use of these instruments poses a substantial risk of unintended bone removal and perforation of the femur if done improperly. These instruments should, as a result, be used under direct vision. Removal of more distal cement in the femur typically requires use of an extended femoral osteotomy (ETO) to allow for adequate access to the well-fixed cement in the bowed femoral canal. An ETO also facilitates more efficient removal of cement in the proximal femur. The ETO should be carefully planned so that it is distal enough to allow for access to the end of the cement column and still allow for stable fixation of a new implant. Too short of an ETO increases the risk of femoral perforation since the straight cement removal instruments cannot negotiate the bowed femoral canal to access the end of the cement column without risk of perforation. An ETO that is too distal makes cement removal easier, but may not allow for sufficient fixation of a new revision femoral stem. Cement below the level of the ETO cannot be directly visualised and specialised instruments are necessary to safely remove this distal cement. Radiofrequency cement removal devices (OSCAR) use high frequency (ultrasonic) radio waves to melt the cement within the canal. Although cement removal with these devices is time consuming and tedious, they do substantially reduce the chances of femoral perforation. These devices can, however, generate considerable heat locally and can result in thermal injury to the bone and surrounding tissues. Once the distal end of the cement mantle is penetrated, backbiting or hooked curettes can be used to remove any remaining cement from within the canal. It is important that all cement be removed from the femur since reamers used for preparation of the distal canal will be deflected by any retained cement, which could result in eccentric reaming and inadvertent perforation of the femur and make fixation of a new implant very challenging. An intraoperative x-ray can be very helpful to insure that all cement has been removed before reaming is initiated

Aseptic loosening and osteolysis may cause significant periprosthetic femoral bone destruction, often necessitating bypass of the deficient proximal femur to obtain stable fixation in the distal diaphysis. The purpose of the present study was to report our results of femoral component revision using a distally locked revision femoral stem for the treatment of the severe proximal femoral bone loss. We evaluated 21 hips in 20 patients who underwent revision hip arthroplasty associated with Paprosky grade-IIIB or IV femoral deficiencies. Three hips were associated with a Vancouver type-B3 periprosthetic femoral fracture. The mean age at the time of revision was 70.8 (51–82) years old with 5 men and 15 women. The mean duration of follow-up was 5.1 years. The femoral implant used for the revision was the Cannulok Revision Prosthesis in 16 hips and the Huckstep interlocking stem in five. Gaps between the stem and the host bone were filled and impacted with bone chips and morselized bone prior to stem insertion. One femoral implants were resected because of deep infection Subsidence was absent and stable fixation was achieved in all patients. Non-progressive radiolucent lines in zones 1 and 7 according to Gruen’s classification were detected in five cases. Cortical hypertrophy around the interlocking screws were seen in ten cases. No disadvantages or complications of the interlocking screws were observed. All the fractures have united within three to five months. Intraoperative fractures in the diaphyseal area occurred in five hips in which trochanteric osteotomy was used. A diaphyseal fixation of the femoral stem with distal interlocking screws appears to provide primary axial and rotational stability of the prosthesis and early mobilization. This implant may provide a satisfactory alternative for the management of revision hip surgery in the presence of a loose femoral component with massive bone loss. Longer-term follow-up data from this study will be needed to confirm these outcomes

Aseptic loosening and osteolysis may cause significant periprosthetic femoral bone destruction, often necessitating bypass of the deficient proximal femur to obtain stable fixation in the distal diaphysis. The purpose of the present study was to report our results of femoral component revision using a distally locked revision femoral stem for the treatment of the severe proximal femoral bone loss. We evaluated 21 hips in 20 patients who underwent revision hip arthroplasty associated with Paprosky grade-IIIB or IV femoral deficiencies. Three hips were associated with a Vancouver type-B3 periprosthetic femoral fracture. The mean age at the time of revision was 70.8 (51–82) years old with 5 men and 15 women. The mean duration of follow-up was 5.1 years. The femoral implant used for the revision was the Cannulok Revision Prosthesis in 16 hips and the Huckstep interlocking stem in five. Gaps between the stem and the host bone were filled and impacted with bone chips and morselized bone prior to stem insertion. One femoral implants were resected because of deep infection Subsidence was absent and stable fixation was achieved in all patients. Non-progressive radiolucent lines in zones 1 and 7 according to Gruen’s classification were detected in five cases. Cortical hypertrophy around the interlocking screws were seen in ten cases. No disadvantages or complications of the interlocking screws were observed. All the fractures have united within three to five months. Intraoperative fractures in the diaphyseal area occurred in five hips in which trochanteric osteotomy was used. A diaphyseal fixation of the femoral stem with distal interlocking screws appears to provide primary axial and rotational stability of the prosthesis and early mobilization. This implant may provide a satisfactory alternative for the management of revision hip surgery in the presence of a loose femoral component with massive bone loss. Longer-term follow-up data from this study will be needed to confirm these outcomes

Introduction: Proximal femoral bone loss, failure of ingrowth, and the use of extended trochanteric osteotomies (ETO) all contribute to loss of proximal support in revision hip arthroplasty. This leads to increased stem stresses, and can lead to the fracture distally fixed, proximally unsupported uncemented revision femoral stems. This study evaluates various cabling and strut techniques to reduce stem stresses seen with bone loss and ETO. Methods: Finite element analysis (FEA) was performed on a clinical case of a fractured revision stem after an ETO. Stem stresses were determined and multiple treatment options were evaluated. An instrumented extensively porous coated stem was implanted in composite femur models (n=3) and mechanically tested. The stem stresses resulting from proximal overbroaching, ETO, cable grips, and various cable and strut constructs were determined. Results: Stem stresses increased 62 percent with a strut cabled above the distal portion of the ETO using FEA methods. This increase was reduced to as little as 10 percent when a third cable was added distal to the ETO. Stem stresses increased 98 when a proximally loose stem was combined with an ETO using laboratory tests. This stress was decreased by up to 37 percent when a long trochanteric plate was utilized. Discussion and Conclusion: This study demonstrates the importance of proximal femoral support to the stresses imparted upon a cementless revision hip prosthesis. In the presence of proximal bone loss, an ETO dramatically increases these stresses, which can be reduced by various cabling and strut techniques

Periprosthetic fractures after total hip arthroplasty are challenging, with potential difficulties associated not only with the fracture but also with implant loosening and bone loss. The incidence of periprosthetic fractures is gradually increasing. We undertook this study to evaluate the periprosthetic fractures presenting to our unit in terms of mechanism of failure, classification and treatment. Charts of patients with periprosthetic fractures presenting within the past six years were retrospectively analysed for demographic and injury details and corresponding radiographs were reviewed to classify the fracture and follow treatment. 45 fractures were identified, with an average age of 78.3 years. The male to female ratio was 5:4. Only 4 fractures occurred in revision prostheses. Two fractures were intraoperative. The Vancouver system was used to classify the fractures, which can also form a basis for treatment. Three fractures of Vancouver type A were managed conservatively without complication. Thirteen fractures were Vancouver type B1, 12 of which underwent internal fixation, mostly plate osteosynthesis; two of these subsequently failed. Recent fractures have been stabilised using locking plates, with no recorded failures. Fifteen fractures were Vancouver type B2, 11 of which were greater than 5 years post arthroplasty. Most underwent revision of the femoral component. Five of these patients had reported pain for some time preceding fracture. Seven fractures were Vancouver type B3, all occurring greater than 7 years post arthroplasty. Most underwent femoral revision. Seven fractures were Vancouver type C, all underwent plate fixation without failure. Although there is variability within the group studied, this series demonstrates gradual standardisation of treatment with use of locking plates and a preferred long revision femoral stem. The reports of pain preceding fracture in a proportion of the Vancouver B2 group prompts greater postoperative surveillance in patients with early signs of femoral loosening