Tapered fluted titanium stems are increasingly used for femoral revision arthroplasty. They are available in modular and non-modular forms. Modularity has advantages when the bone loss is severe, the proximal femur is mis shapen or the surgeon is unfamiliar with the implant, but it introduces the risk of fracture of the stem at the junction between it and the proximal body segment. For that reason, and while awaiting intermediate-term results of more recently introduced designs of this junction, non-modularity has attracted attention, at least for straightforward revision cases. . We review the risks and causes of fracture of tapered titanium modular revision stems and present an argument in favour of the more selective use of modular designs. Cite this article: Bone Joint J 2016;98-B(1 Suppl A):50–3

Aims. When performing revision total hip arthroplasty using diaphyseal-engaging titanium tapered stems (TTS), the recommended 3 to 4 cm of stem-cortical diaphyseal contact may not be available. In challenging cases such as these with only 2 cm of contact, can sufficient axial stability be achieved and what is the benefit of a prophylactic cable? This study sought to determine, first, whether a prophylactic cable allows for sufficient axial stability when the contact length is 2 cm, and second, if differing TTS taper angles (2° vs 3.5°) impact these results. Methods. A biomechanical matched-pair cadaveric study was designed using six matched pairs of human fresh cadaveric femora prepared so that 2 cm of diaphyseal bone engaged with 2° (right femora) or 3.5° (left femora) TTS. Before impaction, three matched pairs received a single 100 lb-tensioned prophylactic beaded cable; the remaining three matched pairs received no cable adjuncts. Specimens underwent stepwise axial loading to 2600 N or until failure, defined as stem subsidence > 5 mm. Results. All specimens without cable adjuncts (6/6 femora) failed during axial testing, while all specimens with a prophylactic cable (6/6) successfully resisted axial load, regardless of taper angle. In total, four of the failed specimens experienced proximal longitudinal fractures, three of which occurred with the higher 3.5° TTS. One fracture occurred in a 3.5° TTS with a prophylactic cable yet passed axial testing, subsiding < 5 mm. Among specimens with a prophylactic cable, the 3.5° TTS resulted in lower mean subsidence (0.5 mm (SD 0.8)) compared with the 2° TTS (2.4 mm (SD 1.8)). Conclusion. A single prophylactic beaded cable dramatically improved initial axial stability when stem-cortex contact length was 2 cm. All implants failed secondary to fracture or subsidence > 5 mm when a prophylactic cable was not used. A higher taper angle appears to decrease the magnitude of subsidence but increased the fracture risk. The fracture risk was mitigated by the use of a prophylactic cable. Cite this article: Bone Jt Open 2023;4(7):472–477

Aims: The purpose of the study was to obtain long-term results after total hip arthroplasty (THA) with cemented titanium stems typ Mueller-Geradschaft. Methods: 91 patients with a total of 110 THA were clinically and radiologically examined after an average follow-up of 9,5 years (9 to 11). The recruitment was 84%. The Harris score was determined clinically. Radiologically the directly postoperative radiographs were compared to the control radiographs according to the recommendations of Gruen et al. and Johnston et al. Results: In 1 cases (1%) a septical complication appeared after two years which was treated in two-stage surgery. Revisions after aseptic loosening have been carried out in 4 cases (4%). No other cases showed evident signs of loosening and applied revision surgery. Clinically, in all of those 4 cases of aseptic loosening the Harris score remained above 75 points. Altogether in 36 cases more than one RLL was ascertained which were only be observed in zones 1, 7, 8, 14. The body weight was significantly higher (82 kg; d=2.4) in the 4 revisions than in cases without RLL, especially the ratio body weight to surface of the stem was clearly different (1.5 kg/cm2 versus 1 kg/cm2; p< 0.005) in the two patients groups. This did not apply to sex, activity, size or kind of stem, Harris-score, ectopic ossification or body-weight index. Conclusions: Cemented titanium stem protheses showed good long-term results. The biggest possible stem should be implanted. Periodically, radiological controls of THA are necessary because the subjective findings of patients does not correlate to the state of prosthesis loosening

Between January 1990 and October 2000, 108 total hip arthroplasties using a cemented polished titanium stem and a cemented ultra-high molecular weight polyethylene (UHMWP) cup were performed at our hospital. Because during routine follow-up visits we noted instances of resorption of the calcar, we decided to assess whether this was a problem. We were able to assess 85 of the original 108 hips. Calcar resorption was observed in 43 hips. The extent of calcar resorption varied from 1 mm to over 15 mm. In one patient a biopsy showed typical polyethylene granuloma. Because there is a risk of long-term failure, we concluded that it is inadvisable to use a cemented polished titanium stem when UHMWP is one of the bearing surfaces

Cementless stem fixation is a widely used method of stem revision in North America and elsewhere in the world. There is abundant literature in its support. Most of the reports from 1985 to 2005 related to proximally or extensively porocoated designs, the former falling into disfavor with time because of unpredictable outcomes. With few exceptions (eg S-ROM) the modularity of these designs was limited to the head/neck junction. But this generation of designs was associated with some issues such as insertional fractures, limited control of anteversion (and risk of dislocation), limited applicability in the setting of severe bone loss (Paprosky Type 4 osteolysis or Vancouver Type B3 periprosthetic fracture), as well as ongoing concern relating to severe proximal stress shielding. In the past decade we have seen the mounting use of a new design concept: tapered fluted titanium stems (TFTS), which incorporate the advantages of titanium (for less flexural rigidity), conical taper (for vertical taper-lock stability), longitudinal ribs and flutes (for rotational stability), and surface preparation which attracts bone on growth for long term fixation. Four consecutive reports from our center have documented the superiority of the TFTS in our hands, with encouraging outcomes even when dealing with severe bone loss or periprosthetic fractures. There is an increasing body of other literature which reports a similar experience. Furthermore, with increasing experience and confidence in this design, we now use a monoblock or non-modular design in greater than 95% of cases in which a TFTS is indicated at our center. This circumvents the potential drawbacks of stem modularity, including taper corrosion and taper junction fracture

Background. KAR™ prosthesis was introduced following the success of Corail® femoral stem to tackle difficult revision cases (Paprosky type1, 2a, 2b and 3a). The ARTO group reported a success rate of 94% at 17 years follow-up. Only two independent studies reported similar success rate to date. Purpose. To analyse the short-term performance of the KAR™ prosthesis used in our unit. Methods. This was a retrospective study of all KAR™ prosthesis between 2005 and 2013. Basic demographic, stem size, indications, failures and complications were recorded. X-rays were analysed for evidence of implant failure and distal cortical hypertrophy. Results. A total of 83 cases were analysed. The mean age was 68 (range 38–88 years) with an average follow-up was 3 years (range 1–8 years). The main indications for revision were aseptic loosening (83.7%), and periprosthetic fractures (7%). Kaplan-Meier Survival Rate for ‘all reasons of failure’ and ‘stem loosening’ was 93.83% and 100% respectively at 3 years follow-up. The most common reason for failure following KAR™ revision was periprosthetic fracture (3 cases). All three cases had radiographic evidence of proximal bone loss prior to index revision. Two patients developed deep infection and one patient had stem subsidence requiring revision. One patient sustained dislocation but revision surgery was not required. When comparing the effect of cortical hypertrophy, there were no significant differences in the measured distal canal/cortical diameter over the entire period of follow-up. Discussion. KAR™ prosthesis offers respectable clinical performance over a short-term period. Revision rate for this system was comparable to other ‘independent non-designer’ study. The three patients that sustained periprosthetic fracture may have been better served with a distally locked stem revision system. We believe that this HA coated implant encourages consistent osseointegration around the metaphysis region when there is evidence of a sound distal fixation. Conclusion. This study confirms that this fully coated hydroxyapatite titanium stem offers reliable clinical performance in revision arthroplasty

Introduction: The Gemini stem (DePuy) is a titanium femoral stem with a modular cobalt chrome femoral head. It has a roughened proximal surface finish to enhance cement bonding and a distal centraliser. Purpose of the study: A retrospective assessment of the performance of the titanium cemented Gemini femoral component. Patients and Methods: 196 patients underwent a 204 total hip replacements using a titanium cemented Gemini stem and an uncemented cup. All the operations were performed by a lateral approach using modern cementing technique. Patients were assessed clinically (Harris hip score) and radiologically (standard AP and lateral x-rays). Results: 11 patients with incomplete clinical and radiological follow-up were excluded from the study, leaving 185 patients (193 hips). 36 patients died with their total hip prosthesis in situ. The average age was 71 years and primary diagnosis was OA in the majority. The average follow-up was 70 months (range 35– 121). 29 of the hips have been revised. A further 11 were recognized as radiological failures. In 24, aseptic loosening or a broken stem was an indication for the revision. Mean time to revision was 3.1 years (range 1.5 to 7). Discussion: Our results indicate that there is a high incidence of early failure associated with these titanium cemented stems, a cumulative failure of approximately 20%. The rough surface finish, titanium alloy and a fixed distal centraliser may all contribute to the early failure by increasing the stresses in the cement. Based on our experience, the continued use of this cemented stem is no longer justified

Introduction:. Severe bone loss creates a challenge for fixation in femoral revision. The goal of the study was to assess reproducibility of fixation and clinical outcomes of femoral revision with bone loss using a modular, fluted, tapered distally fixing stem. Methods:. 92 consecutive patients (96 hips) underwent hip revision surgery using the same design of a modular, fluted, tapered titanium stem between 1998 and 2005. Fourteen patients with 16 hips died before a 2-year follow-up. Eighty hips were followed for an average of 11.3 years (range of 8 to 13.5 years). Bone loss was classified as per Paprosky's classification, osseointegration assessed according to a modified system of Engh et al, and Harris Hip Score was used to document pain and function. Serial radiographs were reviewed by an independent observer to assess subsidence, osseointegration and bony reconstitution. Results:. The average patient age was 68 years at the time of surgery (range 40 to 91). 80% hips had at least Paprosky type 3A proximal bone loss and 41% had an associated proximal femoral ostoetomy. Pre-operative Harris Hip scores (HHS) averaged 50.368 (range 22 to 72.775) and improved to an average HHS of 87.432 (range 63.450 to 99.825) at last follow-up. The HHS improved an average of 37.103 points (range 13.750 to 58.950). Radiographically, osseointegration was evident in all hips. No hips had measurable migration beyond 5 mm. 61%) hips had evidence of bone reconstitution and 27% demonstrated diaphyseal stress shielding. One well-fixed distal stem was revised for stem fracture, and two proximal segments were revised for recurrent dislocation. Conclusion:. Reproducible fixation and clinical improvement were consistently achieved with this stem design in the setting of femoral bone loss

Introduction. Studies have documented encouraging results with the use of fluted, tapered, modular, titanium stems in revision hip arthroplasty with bone loss. However, radiographic signs of osseointegration and patterns of reconstitution have not been previously categorized. Materials and Methods. 64 consecutive hips with index femoral revision using a particular stem of this design formed the study cohort. Serial radiographs were retrospectively reviewed by an independent observer. Bone loss was determined by Paprosky's classification. Osseointegration was assessed by a slight modification of the criteria of Engh et al. Femoral restoration was classified according to Kolstad et al. Pain and function was documented using Harris Hip Score (HHS). Results. Mean patient age was 68.3 years and radiographic follow-up 6.2 years. 74% femora had type 3 or 4 bone loss. All distal segments were radiographically osseointegrated. Proximal segment radiolucent lines were frequent (40%). Early minor subsidence occured in 4 (6.2%) hips. Definite bony regeneration was documented in 73% femora and stress-shielding in 26%. HHS improved from a pre-operative mean of 50.1 points to 86.2 at most recent follow-up. Discussion. A consistent pattern of bony remodeling and osseointegration occurred which could be applied for assessment of fixation and stability of this stem. The well established criteria of osseointegration for cylindrical cobalt-chrome stems may have to be altered for application to these stems as the mechanism of load transfer is entirely different. Stems with diameter of 18mm or greater are clearly predisposed to stress shielding, predominantly at the mid-shaft region

Non-modular tapered fluted, titanium stems are available for use in femoral revision. The combination of taper and flutes on the stem provides axial and rotational stability, respectively. The material and surface properties of the stem promotes bone on-growth. If the surgeon is confident and reasonably experienced in the surgical use of this sort of design and the case is relatively straightforward, a non-modular design is effective. It also potentially reduces implant inventory, and circumvents the potential problems of taper junction corrosion and fatigue fracture. There are reports of excellent survival, good clinical and functional results and evidence of subsequent increase in proximal bone stock. Cite this article: Bone Joint J 2014;96-B(11 Suppl A):56–9

Objective: Revision total hip arthroplasty in cases of proximal femoral bone loss due to osteolysis and loosening is challenging for surgeon and implants. The use of tapered fluted modular titanium femoral stem in these situations may offer the advantage of better biomechanical reconstruction with a design that ensure primary stability and promotes bone integration. Method: We studied retrospectively 83 cases of femoral reconstruction with the PFM-R stem. Paprosky classification was used to qualify bone defects on preoperative radiological evaluation. Demographic, clinical and intraoperative data were collected, along with any complications. Clinical (W.O.M.A.C. function score) and radiological follow-up was performed at a minimum of 12 months. Results: The mean follow-up was 44 months (23 to 66 months). Five patients were lost to follow-up. 48% of patients had at least one previous revision. The mean post operative WOMAC score was 83. 91% of patients had no significant limb length discrepancy. Stabilization or regression of osteolytic lesions was observed in 75% of revised femur. Complications were 8 dislocations, 7 fractures and 3 infections. A correlation was found between the risk of dislocation and the number of previous revision surgery. Out of 14 cases revised for infection, one had a recurrence. Discussion: This study confirmed the benefits of the PFM-R stem in difficult femoral revision in term of limb length equalization, stability of fixation, regression of osteolytic lesions and improved clinical function

Cemented titanium stems in hip arthroplasty are associated with proximal cement-stem debonding and early failure. This was well publicised with the 3M Capital hip. However, corrosion in this setting has been reported with only one stem design and is less widely accepted. We present a series of 12 cemented titanium Furlong Straight Stems which required revision at a mean of 78 months for thigh pain. At revision the stems were severely corroded in a pattern which was typical of crevice corrosion. Symptoms were eliminated after revision to an all-stainless steel femoral prosthesis of the same design. We discuss the likely causes for the corrosion. The combination of a titanium stem and cement appears to facilitate crevice corrosion

Starting in 1977 a new cemented stem made of titanium alloy (with vanadium) was designed regarding some principle: rectangular shape, smooth surface covered with thin layer of titanium oxide, filling the medullar cavity. As a consequence: a thin layer of cement. It was designed with a collar. Initial Cementing technique used dough cement, vent tube and finger packing; then we applied cement retractor low viscosity cement and sometimes Harris Syringe. At the moment we went back to initial technique plus a cement retractor made of polyethylene. Many papers looked at long term follow up results depicting about 98 to 100 percent survivors at 10 years and 95 to 98% at 20 years (Hernigou, Hamadouche, Nizard, El Kaim). Clinical as well as radiological results are available. Radiological results depicted some radiolucent lines that appeared at the very long term. They could be related to friction between the stem and the cement. As advocated by Robin Ling, he called “French paradox” the fact that if a cemented prosthesis is smooth and fills the medullary cavity, long term excellent results could be expected. This was the case with stainless steel Kerboull shape, the Ling design (Exeter)and the Ceraver design. The majority of these stems were implanted with an all alumina bearing system. And in some occasion, when revision had to be performed, the stem was left in place (108 cases over 132 revisions). Our experience over more than 5000 stems implanted is outstanding (see figure 1: aspect after 30 years). Discussion other experience with cemented titanium stem were bad (Sarmiento, Fare). We suspect that this was related either to the small size of this flexible material, or to the roughness of its surface. If one uses titanium cemented stem it must be large enough and extra smooth

This is a retrospective assessment of the performance of the titanium cemented Gemini femoral component. The Gemini stem (DePuy) is a modular titanium femoral stem with a cobalt chrome femoral head. It has a roughened proximal surface finish to enhance cement bonding and a fixed distal centraliser. 205 total hip replacements were performed using a titanium cemented Gemini stem and an uncemented cup. All the operations were performed by a lateral approach using modern cementing technique. Patients were assessed clinically (Harris hip score) and radiologically. Kaplan Meier Survivorship analysis was used to assess survival. 8 patients were lost and 36 patients died with their total hip prosthesis in situ. The average follow-up in the remaining 161 hips was 70 months (range 37–124 months). The average age was 70 years (range 35–91). Osteoarthritis was the commonest diagnosis and majority of the patients was female. Using the Barrack’s criteria for cementing quality, more than 85% of the hips belonged either to grade A or B with an adequate proximal cement mantle. 28 hips have been revised (26 of which for aseptic loosening) and a further ten have been recognized as radiological failures. A small sized stem was used in over 85% of the failures. Mean time to revision was 3.1 years. Survival according to Kaplan-Meier Survivor curves at 6 years was 72%. There is a high incidence of early failure associated with these cemented titanium stems (28%). The possible mechanism of failure is as follows. The rough surface finish and the flexible titanium alloy are likely to produce large amounts of wear debris and the centraliser which is fixed to the stem probably acts as an area of stress concentration causing accelerated destruction of the distal cement mantle. Based on our experience, the continued use of this cemented stem is no longer justified

We reviewed the outcome of prosthesis-to-bone fixation of the rough titanium femoral stem of an Ultraloc prosthesis (Zimmer, USA). Between 1989 and 1991, 41 of 55 patients were traced for long-term review at a mean of 107 months (55 to 139). The primary pathology was avascular necrosis in 18 patients, osteoarthritis in 16, ankylosing spondylitis in two and Perthes’ disease in one, and there were two cases each of trauma and dysplasia. There was an equal number of men and women, whose mean age at operation was 47 years (24 to 66). Radiological assessment of the stems revealed well-fixed stems in 40 patients (97.6%). In 20 stems small granulomata due to polyethylene wear were found in Gruen zones 1 and 7, and in one stem in zones 1, 6 and 7. Only one stem required revision for loosening (done at 59 months), but cups (48.8%) were loose. Three patients required revision owing to polyethylene wear and one for sepsis. In all four cases, removal of the stem was extremely difficult. The remaining 16 hips await revision. Although the results obtained using an Ultraloc prosthesis are poor, from the point of view of fixation the stem has functioned successfully. However, the formation of granulomata causes cup loosening

Background: Hydroxyapatite (HA) coating is widely used for total hip arthroplasty as it has been suggested to improve implant ingrowth and long-term stability. However, the evidence behind the use of HA in femoral stems is ambiguous. Methods: We investigated a non-cemented, tapered titanium femoral stem that was available either with or without HA coating. This stem had been used in 3,116 total hip arthroplasties (THAs) in 2,608 patients registered in the Swedish Hip Arthroplasty Register (1992–2007). Kaplan-Meier survival analysis and a Cox regression model including type of coating, age, sex, primary diagnosis, and the type of cup fixation were used to calculate adjusted risk ratios (RR) of the risk for revision for various reasons. Results: 63.7% of the stems were coated with HA, 36.3% were uncoated. It was found that the investigated HA-coated stem had an excellent 10-year survivorship of 97.7% (95% CI 96.5–98.9), and that the stem without HA coating had a 10-year survivorship of 97.6% (95% CI 96.2–99.0) when revision due to any reason was defined as the endpoint. There was no significant difference between these two groups (p> 0.05, log rank Mantel-Cox). A Cox regression model showed that the presence of HA coating did not significantly influence the risk of stem revision due to any reason (RR 1.3; 95% CI 0.7–2.4), or due to aseptic loosening (RR 1.0; 95% CI 0.3–3.4). The risk for revision due to infection, dislocation, or fracture was also not affected by the presence of HA coating. Interpretation: Our results show HA coating of this non-cemented tapered stem with excellent 10-year survivorship does not affect the risk for revision. The assumed beneficial effect of HA coating of femoral stems in total hip arthroplasty is thus questionable

We present our results of cementless total hip arthroplasty with a tapered, rectangular stem made of titanium-aluminum-niobium alloy. This implant is used since 1979 with only minor modifications. The design of the femoral component achieves primary stability through precision rasping and press-fit implantation.

Between October 1986 and November 1987, two hundred consecutive patients (208 hips) underwent total hip arthroplasty with this tapered, rectangular stem. In all cases the acetabular component was a threaded cup made of titanium.

At a minimum follow-up of twenty years eighty-seven patients were still alive. Sixty-seven patients (69 hips) were available for clinical and radiographic follow-up. The probability of survival of the stem was 0.96 (95% confidence interval, 0.91 to 0.98) and that of the cup was 0.72 (0.62 to 0.80). The probability of survival of both the stem and the acetabular component with revision for any reason as the end point was 0.71 (0.61 to 0.78).

Two stems have been revised due to aseptic loosening. We found various degrees of osteolysis around the acetabular and femoral component (61,7%). At the time of the 20-year follow-up no stem was deemed at risk for loosening.

The key findings of our twenty-year follow-up are the very low rate of revisions of the femoral component and the low rate of distal femoral osteolysis associated with this stem. Our data show that femoral fixation of the stem continues to be secure at a follow-up of twenty years.

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. Methods. A retrospective review was conducted of all patients who underwent revision THA (rTHA) for periprosthetic UCS B2 and B3 periprosthetic fracture who received a single design monoblock fluted tapered titanium stem at two large, tertiary care, academic hospitals. A total of 72 patients met inclusion and exclusion criteria (68 UCS B2, and four UCS B3 fractures). Primary outcomes of interest were radiological stem subsidence (> 5 mm), radiological osseointegration, and fracture union. Sub-analysis was also done for 46 patients with minimum one-year follow-up. Results. For the total cohort, stem osseointegration, fracture union, and stem subsidence were 98.6%, 98.6%, and 6.9%, respectively, at latest follow-up (mean follow-up 27.0 months (SD 22.4)). For patients with minimum one-year of follow-up, stem osseointegration, fracture union, and stem subsidence were 97.8%, 97.8%, and 6.5%, respectively. Conclusion. Monoblock fluted stems can be an acceptable modality for the management of UCS B2 periprosthetic fractures in rTHAs due to high rates of stem osseointegration and survival, and the low rates of stem subsidence, and revision. Further research on the use of this stem for UCS B3 periprosthetic fractures is warranted to determine if the same conclusion can be made for this fracture pattern. Cite this article: Bone Jt Open 2023;4(8):551–558

To review the results of revision THR performed with a modular titanium tapered uncemented stem in two cohorts of patients to assess whether subsidence of this type of stem is avoidable through improved surgical technique.

The first 70 patients undergoing revision THR with this type of stem were compared with 38 patients who had their revision in the last 24 months and had a minium follow up of 12 months., with particular reference to stem subsidence. All patients were also assessed with the Oxford Hip Score. All radiographs were reviewed to measure subsidence. Identical post-operative management was used in both groups.

The mean subsidence in the first group was 11.7 mm and in the most recent group 4mm. The Oxford Hip Score in both groups was similar (20.9) which compares very favourably with the OHS score from the National joint Register for revision arthroplasty (24.3).

This comparison shows that changes in surgical technique can limit the subsidence seen with tapered stems used in revision total hip replacement. No bone grafts were used in either series, only small changes in bone preparation, and prosthesis selection were used .The outcome as determined by the OHS was similar in both groups.

We report the results of a cementless modular revision component which has been used in our hospital since 1993. There were 103 patients, in which the aforementioned cementless femoral revision component was used. Patients were evaluated, using both a modiþed HHS and serial radiographs performed preoperatively, at 2 weeks, 3 months and annually postoperatively. The patients were followed for a minimum of 4 years. Pre-operatively, bony defects were classiþed on radiographs according to the classiþcation of Mallory. Three hips were excluded from the evaluation: 1 was lost to follow-up and 2 were deceased. 100 hips with an average follow-up of 75 months were retrospectively reviewed. Indication for revision was aseptic loosening in 96 cases and infection in 4. Average number of previous hip surgeries in this patient group was 2.3. Average pre-operative hip score was 48,8 compared to an average postoperative hip score of 74,4. Postoperative complications included 2 infections and 2 cases of DVT with occurrence of PE in 1 case, 4 postoperative dislocations, 2 cases with radiographic subsidence of the femoral component and 1 case with sciatic nerve lesion. Intraoperative complications included femoral fractures upon dislocation of the hip or impaction of the new stem in 37 cases. At time of latest review there were no clinical or radiographic signs of component loosening. The incidence of postoperative and intraoperative complications are comparable to the literature. Clinical and radiographic results of the cementless, modular titanium revision component are promising and support its continued use.

The goals of revision total hip on the femoral side are to achieve long term stable fixation, improve quality of life and minimise complications such as intra-operative fracture or dislocation. Ideally these stems will preserve or restore bone stock. Modular titanium stems were first introduced in North America around 2000. They gained popularity as an option for treating Paprosky 3B and 4 defects. Several studies at our institution have compared modular titanium stems with monoblock cobalt chromium stems. The main outcomes of interest were quality of life. We also looked at complications such as intra-operative fracture and post-operative dislocation. We also compared these 2 stems with respect to restoration or preservation of bone stock. In 2 studies we showed that modular titanium stems gave superior functional outcomes as well as decreased complications compared to a match cohort of monoblock cobalt chromium stems. As mentioned, one of the initial reasons for introduction of these stems was to address larger femoral defects where failure rates with monoblock cobalt chromium stems were unacceptably high. We followed a group of 65 patients at 5–10 years post revision with a modular fluted titanium stem. Excellent fixation was obtained with no cases of aseptic loosening. However, there were 5 cases of fracture of the modular junction. Due to concerns of fracture of the modular junction, more recently, at our institution, we have switched to almost 100% monoblock fluted titanium stems. We recently reviewed our first 100 cases of femoral revision with a monoblock stem. Excellent fixation was achieved with no cases of aseptic loosening. Quality of life outcomes were similar to our previous reported series on modular tapered titanium stems. Both monoblock and modular fluted titanium stems can give excellent fixation and excellent functional outcomes. This leaves a choice for the surgeon. For the low volume revision surgeon modular tapered stems are probably the right choice. Higher volume surgeons or surgeons very comfortable with performing femoral revision may want to consider monoblock stems. If one is making the switch it would be easiest to start with a simple case. Such a case would be one that can be done with a endofemoral approach. In this approach the greater trochanter is available as the key landmark for reaming. After the surgeon is comfortable with this stem more complex cases can easily be handled with the monoblock stem. In summary, both modular and monoblock titanium stems are excellent options for femoral revision. As one becomes more familiar with the monoblock stem it can easily become your workhorse for femoral revision. At our institution we introduced a monoblock titanium stem in 2011. It started out at 50% of cases and now it is virtually used in almost 100% of revision cases

The goals of revision total hip on the femoral side are to achieve long term stable fixation, improve quality of life and minimise complications such as intra-operative fracture or dislocation. Ideally these stems will preserve or restore bone stock. Modular titanium stems were first introduced in North America around 2000. They gained popularity as an option for treating Paprosky 3B and 4 defects. Several studies at our institution have compared the modular titanium stems with monoblock cobalt chromium stems. The main outcomes of interest were quality of life. We also looked at complications such as intra-operative fracture and post-operative dislocation. We also compared these 2 stems with respect to restoration or preservation of bone stock. In 2 studies we showed that modular titanium stems gave superior functional outcomes as well as decreased complications compared to a match cohort of monoblock cobalt chromium stems. As mentioned one of the initial reasons for introduction of these stems was to address larger femoral defects where failure rates with monoblock cobalt chromium stems were unacceptably high. We followed a group of 65 patients at 5–10 years post-revision with a modular fluted titanium stem. Excellent fixation was obtained with no cases of aseptic loosening. However, there were 5 cases of fracture of the modular junction. Due to concerns of fracture of the modular junction more recently at our institution we have switched to almost 100% monoblock fluted titanium stems. We recently reviewed our first 100 cases of femoral revision with monoblock stem. Excellent fixation was achieved with no cases of aseptic loosening. Quality of life outcomes were similar to our previous reported series on modular tapered titanium stems. Both monoblock and modular fluted titanium stems can give excellent fixation and excellent functional outcomes. This leaves a choice for the surgeon. For the low volume revision surgeon modular tapered stems are probably the right choice. Higher volume surgeons or surgeons very comfortable with performing femoral revision may want to consider monoblock stems. If one is making the switch it would be easiest to start with a simple case. Such a case would be one that can be done with an endofemoral approach. In this the greater trochanter is available as the key landmark for reaming. After the surgeon is comfortable with this stem more complex cases can easily be handled with the monoblock stem. In summary, both modular and monoblock titanium stems are excellent options for femoral revision. As one becomes more familiar with the monoblock stem it can easily become your workhorse for femoral revision. At our institution we introduced a monoblock titanium stem in 2011. It started out at 50% of cases and now it is virtually used in almost 100% of revision cases

The goals of revision total hip on the femoral side are to achieve long term stable fixation, improve quality of life and minimise complications such as intra-operative fracture or dislocation. Ideally these stems will preserve or restore bone stock. Modular titanium stems were first introduced in North America around 2000. They gained popularity as an option for treating Paprosky 3B and 4 defects. Several studies at our institution have compared the modular titanium stems with monoblock cobalt chromium stems. The main outcomes of interest were quality of life. We also looked at complications such as intra-operative fracture and post-operative dislocation. We also compared these 2 stems with respect to restoration or preservation of bone stock. In two studies we showed that modular titanium stems gave superior functional outcomes as well as decreased complications compared to a matched cohort of monoblock cobalt chromium stems. As mentioned one of the initial reasons for introduction of these stems was to address larger femoral defects where failure rates with monoblock cobalt chromium stems were unacceptably high. We followed a group of 65 patients at 5–10 years post-revision with a modular fluted titanium stem. Excellent fixation was obtained with no cases of aseptic loosening. However, there were 5 cases of fracture of the modular junction. Due to concerns of fracture of the modular junction more recently, at our institution we have switched to almost 100% monoblock fluted titanium stems. We recently reviewed our first 100 cases of femoral revision with monoblock stem. Excellent fixation was achieved with no cases of aseptic loosening. Quality of life outcomes were similar to our previous reported series on modular tapered titanium stems. Both monoblock and modular fluted titanium stems can give excellent fixation and excellent functional outcomes. This leaves a choice for the surgeon. For the low volume revision surgeon modular tapered stems are probably the right choice. Higher volume surgeons or surgeons very comfortable with performing femoral revision may want to consider monoblock stems. If one is making the switch it would be easiest to start with a simple case. Such a case would be one that can be done through an endofemoral approach. In this the greater trochanter is available as the key landmark for reaming. After the surgeon is comfortable with this system more complex cases can easily be handled with the monoblock stem. In summary, both modular and monoblock titanium stems are excellent options for femoral revision. As one becomes more familiar with the monoblock stem it can easily become your workhorse for femoral revision. At our institution, we introduced a monoblock titanium stem in 2011. It started out at 50% of cases and now it is virtually used in almost 100% of revision cases

Aims. Femoral stems with exchangeable (modular) necks were introduced to offer surgeons an increased choice when determining the version, offset and length of the femoral neck during total hip arthroplasty (THA). It was hoped that this would improve outcomes and reduce complications, particularly dislocation. In 2010, the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) first reported an increased rate of revision after primary THA using femoral stems with an exchangeable neck. The aim of this study was to provide a more comprehensive up-to-date analysis of primary THA using femoral stems with exchangeable and fixed necks. Materials and Methods. The data included all primary THA procedures performed for osteoarthritis (OA), reported to the AOANJRR between 01 September 1999 and 31 December 2014. There were 9289 femoral stems with an exchangeable neck and 253 165 femoral stems with a fixed neck. The characteristics of the patients and prostheses including the bearing surface and stem/neck metal combinations were examined using Cox proportional hazard ratios (HRs) and Kaplan-Meier estimates of survivorship. . Results. It was found that prostheses with an exchangeable neck had a higher rate of revision and this was evident regardless of the bearing surface or the size of the femoral head. Exchangeable neck prostheses with a titanium stem and a cobalt-chromium neck had a significantly higher rate of revision compared with titanium stem/titanium neck combinations (HR 1.83, 95% confidence interval 1.49 to 2.23, p < 0.001). Revisions were higher for these combinations compared with femoral stems with a fixed neck. Conclusion . There appears to be little evidence to support the continued use of prostheses with an exchangeable neck in primary THA undertaken for OA. Cite this article: Bone Joint J 2017;99-B:766–73

We had previously reported on early outcomes on a new fluted, titanium, monobloc stem with a three degree taper that has been designed for challenging femoral reconstruction in the setting of extensive bone loss. The aim of this study was to report its mid-term clinical and radiographic outcomes. This is a retrospective review of prospectively collected data carried out at a single institution between Jan 2017 and Dec 2019. 85 femoral revisions were performed using a new tapered, fluted, titanium, monobloc (TFTM) revision stem. Complications, clinical and radiographic data were obtained from medical records and a locally maintained database. Clinical outcomes were assessed using the Oxford Hip Score (OHS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). All post-operative radiographs were analysed for subsidence, osteolysis and femoral cortical bone remodelling. Mean follow-up was 60 months (range 28–84 months). Subsidence of 1.2 mm was noted in one patient. No cases of clinically significant subsidence (10 mm) were observed. At final follow-up, a statistically significant improvement was noted in functional outcome scores. The mean OHS preoperatively and at final follow-up were 24 (SD 13) and 42 (SD15). p = 0.04 mean difference 18 (95% CI 15–22). The mean WOMAC scores preoperatively and at final follow-up were 62 (SD23) and 88 (SD7) respectively (p < 0.001, mean difference 26; 95% CI 21–34). No stem fractures were noted within the follow-up period. Two patients had revision of the stem's one for infection and another for persistent pain. Positive mid-term clinical and radiological outcomes have been observed with this tapered, fluted, titanium, monobloc stem. Based on these results, this implant may be considered as a viable option in the majority of uncemented femoral revisions

In recent years, cementless stems have dominated the North American market. There are several categories of cementless stems, but in the past 20 years, the two most popular designs in the United States have been the extensively coated cylindrical cobalt-chrome (CoCr) stem and the proximally coated tapered titanium stem, which in recent years has become the most common. The 10-year survival for both stem types has been over 95% with a distinction made on factors other than stem survival, including thigh pain, stress shielding, complications of insertion, and ease of revision. Conventional wisdom holds that proximally coated titanium stems have less stress shielding, less thigh pain, and a higher quality clinical result. Recent studies, however, including randomised clinical trials have found that the incidence of thigh pain and clinical result is essentially equivalent between the stem types, however, there is a modest advantage in terms of stress shielding for a tapered titanium stem over an extensively coated CoCr stem. One study utilizing pain drawings did establish that if a CoCr cylindrical stem was utilised, superior clinical results in terms of pain score and pain drawings were obtained with a fully coated versus a proximally coated stem. In spite of the lack of a clinically proven advantage in randomised trials, tapered titanium stems have been favored because of the occasional occurrence of substantial stress shielding, the increased clinical observation of thigh pain severe enough to warrant surgical intervention, ease of use of shorter tapered stems that involve removal of less trochanteric bone and less risk of fracture both at the trochanter and the diaphysis due to the shorter, and greater ease of insertion through more limited approaches, especially anterior approaches. When tapered stems are utilised, there may be an advantage to a more rectangular stem cross-section in patients with type C bone. In spite of the numerous clinical advantages of tapered titanium stems, there still remains a role for more extensively coated cylindrical stems in patients that have had prior surgery of the proximal femur, particularly for a hip fracture, which makes proximal fixation, ingrowth, and immediate mechanical stability difficult to assure consistently. Cement fixation should also be considered in these cases. While the marketplace and the clinical evidence strongly support routine use of tapered titanium proximally coated relatively short stems with angled rather than straight proximal lateral geometry in the vast majority of cases, there still remains a role for more extensively coated cylindrical and for specific indications

In recent years, cementless stems have dominated the North American market. There are several categories of cementless stems, but in the past 20 years, the two most popular designs in the United States have been the extensively coated cylindrical cobalt-chrome (Co-Cr) stem and the proximally coated tapered titanium stem, which in recent years has become the most common. The 10-year survival for both stem types has been over 95% with a distinction made on factors other than stem survival, including thigh pain, stress shielding, complications of insertion, and ease of revision. Conventional wisdom holds that proximally coated titanium stems have less stress shielding, less thigh pain, and a higher quality clinical result. Recent studies, however, including randomised clinical trials have found that the incidence of thigh pain and clinical result is essentially equivalent between the stem types, however, there is a modest advantage in terms of stress shielding for a tapered titanium stem over an extensively coated Co-Cr stem. One study utilising pain drawings did establish that if a Co-Cr cylindrical stem was utilised, superior clinical results in terms of pain score and pain drawings were obtained with a fully coated versus a proximally coated stem. In spite of the lack of a clinically proven advantage in randomised trials, tapered titanium stems have been favored because of the occasional occurrence of substantial stress shielding, the increased clinical observation of thigh pain severe enough to warrant surgical intervention, ease of use of shorter tapered stems that involve removal of less trochanteric bone and less risk of fracture both at the trochanter and the diaphysis due to the shorter, and greater ease of insertion through more limited approaches, especially anterior approaches. When tapered stems are utilised, there may be an advantage to a more rectangular stem-cross section in patients with type C bone. In spite of the numerous clinical advantages of tapered titanium stems, there still remains a role for more extensively coated cylindrical stems in patients that have had prior surgery of the proximal femur, particularly for a hip fracture, which makes proximal fixation, ingrowth, and immediate mechanical stability difficult to assure consistently. Cement fixation should also be considered in these cases. While the marketplace and the clinical evidence strongly support routine use of tapered titanium proximally coated relatively short stems with angled rather than straight proximal lateral geometry in the vast majority of cases, there still remains a role for more extensively coated cylindrical and for specific indications

In recent years, cementless stems have dominated the North American market. There are several categories of cementless stems, but in the past 20 years, the two most popular designs in the United States have been the extensively coated cylindrical cobalt-chrome (CoCr) stem and the proximally coated tapered titanium stem, which in recent years has become the most common. The 10 year survival for both stem types has been over 95% with a distinction made on factors other than stem survival, including thigh pain, stress shielding, complications of insertion, and ease of revision. Conventional wisdom holds that proximally coated titanium stems have less stress shielding, less thigh pain, and a higher quality clinical result. Recent studies, however, including randomised clinical trials have found that the incidence of thigh pain and clinical result is essentially equivalent between the stem types, however, there is a modest advantage in terms of stress shielding for a tapered titanium stem over an extensively coated CoCr stem. One study utilising pain drawings did establish that if a CoCr cylindrical stem was utilised, superior clinical results in terms of pain score and pain drawings were obtained with a fully coated versus a proximally coated stem. In spite of the lack of a clinically proven advantage in randomised trials, tapered titanium stems have been favored because of the occasional occurrence of substantial stress shielding, the increased clinical observation of thigh pain severe enough to warrant surgical intervention, ease of use of shorter tapered stems that involves removal of less trochanteric bone and less risk of fracture both at the trochanter and the diaphysis due to the shorter, and greater ease of insertion through more limited approaches, especially anterior approaches. When tapered stems are utilised, there may be an advantage to a more rectangular stem-cross section in patients with type C bone. In spite of the numerous clinical advantages of tapered titanium stems, there still remains a role for more extensively coated cylindrical stems in patients that have had prior surgery of the proximal femur, particularly for a hip fracture, which makes proximal fixation, ingrowth, and immediate mechanical stability difficult to assure consistently. Cement fixation should also be considered in these cases. While the market place and the clinical evidence strongly support routine use of tapered titanium proximally coated relatively short stems with angled rather than straight proximal lateral geometry in the vast majority of cases, there still remains a role for more extensively coated cylindrical and for specific indications

In recent years, cementless stems have dominated the North American market. There are several categories of cementless stems, but in the past 20 years, the two most popular designs in the United States have been the extensively coated cylindrical cobalt-chrome (Co-Cr) stem and the proximally coated tapered titanium stem, which in recent years has become the most common. The 10 year survival for both stem types has been over 95% with a distinction made on factors other than stem survival, including thigh pain, stress shielding, complications of insertion, and ease of revision. Conventional wisdom holds that proximally coated titanium stems have less stress shielding, less thigh pain, and a higher quality clinical result. Recent studies, however, including randomised clinical trials have found that the incidence of thigh pain and clinical result is essentially equivalent between the stem types, however, there is a modest advantage in terms of stress shielding for a tapered titanium stem over an extensively coated Co-Cr stem. One study utilising pain drawings did establish that if a Co-Cr cylindrical stem was utilised, superior clinical results in terms of pain score and pain drawings were obtained with a fully coated versus a proximally coated stem. In spite of the lack of a clinically proven advantage in randomised trials, tapered titanium stems have been favored because of the occasional occurrence of substantial stress shielding, the increased clinical observation of thigh pain severe enough to warrant surgical intervention, ease of use of shorter tapered stems that involve removal of less trochanteric bone and less risk of fracture both at the trochanter and the diaphysis due to the shorter, and greater ease of insertion through more limited approaches, especially anterior approaches. When tapered stems are utilised, there may be an advantage to a more rectangular stem-cross-section in patients with type C bone. In spite of the numerous clinical advantages of tapered titanium stems, there still remains a role for more extensively coated cylindrical stems in patients that have had prior surgery of the proximal femur, particularly for a hip fracture, which makes proximal fixation, ingrowth, and immediate mechanical stability difficult to assure consistently. Cement fixation should also be considered in these cases. While the marketplace and the clinical evidence strongly support routine use of tapered titanium proximally coated relatively short stems with angled rather than straight proximal lateral geometry in the vast majority of cases, there still remains a role for more extensively coated cylindrical and for specific indications

Aims. Although good clinical outcomes have been reported for monolithic tapered, fluted, titanium stems (TFTS), early results showed high rates of subsidence. Advances in stem design may mitigate these concerns. This study reports on the use of a current monolithic TFTS for a variety of indications. Methods. A multi-institutional retrospective study of all consecutive total hip arthroplasty (THA) and revision total hip arthroplasty (rTHA) patients who received the monolithic TFTS was conducted. Surgery was performed by eight fellowship-trained arthroplasty surgeons at four institutions. A total of 157 hips in 153 patients at a mean follow-up of 11.6 months (SD7.8) were included. Mean patient age at the time of surgery was 67.4 years (SD 13.3) and mean body mass index (BMI) was 28.9 kg/m. 2. (SD 6.5). Outcomes included intraoperative complications, one-year all-cause re-revisions, and subsidence at postoperative time intervals (two weeks, six weeks, six months, nine months, and one year). Results. There were eight intraoperative complications (4.9%), six of which were intraoperative fractures; none occurred during stem insertion. Six hips (3.7%) underwent re-revision within one year; only one procedure involved removal of the prosthesis due to infection. Mean total subsidence at latest follow-up was 1.64 mm (SD 2.47). Overall, 17 of 144 stems (11.8%) on which measurements could be performed had >5 mm of subsidence, and 3/144 (2.1%) had >10 mm of subsidence within one year. A univariate regression analysis found that additional subsidence after three months was minimal. A multivariate regression analysis found that subsidence was not significantly associated with periprosthetic fracture as an indication for surgery, the presence of an extended trochanteric osteotomy (ETO), Paprosky classification of femoral bone loss, stem length, or type of procedure performed (i.e. full revision vs conversion/primary). Conclusion. Advances in implant design, improved trials, a range of stem lengths and diameters, and high offset options mitigate concerns of early subsidence and dislocation with monolithic TFTS, making them a valuable option for femoral revision. Cite this article: Bone Joint J 2020;102-B(2):191–197

Adverse reaction to metal debris (ARMD) is well recognised as a complication of large head metal on metal total hip replacement (THR) leading to pain, bone and tissue loss and the need for revision surgery. An emerging problem of trunnionosis in metal on polyethylene total hip replacements leading to ARMD has been reported in a few cases. Increased metal ion levels have been reported in THR's with a titanium stem and a cobalt chrome head such as the Accolade-Trident THR (Stryker). We present 3 cases of ARMD with Accloade-Trident THR's with 36mm cobalt chrome head and a polyethylene liner. Metal ion levels were elevated in all three patients (cobalt 10.3 – 161nmol/l). Intraoperative tissue samples were negative for infection and inflammatory markers were normal. Abnormal fluid collections were seen in all three cases and bone loss was severe in one patient leading to a proximal femoral replacement. Histology demonstrated either a non-specific inflammatory reaction in a case which presented early or a granulomatous reaction in a more advanced case suggesting a local foreign body reaction. All patients had improved symptoms post-operatively. 1 patient who had staged bilateral Accolade-Trident THR's required revision of both THR's. ARMD in metal on polyethylene THR's with a titanium stem represents a potential emerging problem. Further studies are required to assess whether these occurrences are rare or represent the tip of an iceberg

INTRODUCTION. Corrosion of modular tapers is increasingly recognized as a source of adverse tissue reaction (ALTR) and revision surgery in total hip arthroplasty (THA). The incidence of corrosion and rate of revision for ALTR may differ among different types of implants. OBJECTIVE. The objective of this study was to determine if a difference exists in rate of THA revision for corrosion and ALTR with tapered broach only stems compared to ream-broach femoral stems. METHODS. We reviewed the results of 3741 primary THA performed over a 5 year period at our institution using 2 different implants by the same manufacturer, a tapered proximally coated cementless titanium stem inserted via a broach only technique (Group A) and dual tapered proximally coated cementless titanium stem inserted via a ream and broach technique (Group B). RESULTS. Of 1567 THA in group A, 964 were combined with a chrome cobalt metal head, while 603 were ceramic. Of 2174 THA in group B, 1302 were metal and 872 were ceramic. Head sizes used were similar between groups. The same polyethylene was used in all THA. At a minimum follow-up of 2 years and average follow-up of 5 years, the overall revision rate for all causes was 3.1% in group A and 1.4% in group B. There were 29 revisions for ALTR due to corrosion of the morse taper junction in group A (3.4%) and 0 in group B. Univariate and multivariate analysis indicated no relationship between revision for corrosion/ALTR and age, gender, stem size, stem offset and head size. A significant relationship was identified between revision and head length, with an increased rate of revision among longer head lengths. There were no revisions for corrosion, ALTR or unexplained pain among patients receiving ceramic heads in either group. CONCLUSION. There was a significant difference in the rate of revision for corrosion and adverse tissue reaction encountered with the use of stem A when compared to stem B. The stem geometry, taper geometry and exact metallurgy of these femoral components likely influences the incidence and severity of taper corrosion, however, more research is required to identify the exact contributions of these factors

Aims. The aim of this study was to develop a novel computational model for estimating head/stem taper mechanics during different simulated assembly conditions. Methods. Finite element models of generic cobalt-chromium (CoCr) heads on a titanium stem taper were developed and driven using dynamic assembly loads collected from clinicians. To verify contact mechanics at the taper interface, comparisons of deformed microgroove characteristics (height and width of microgrooves) were made between model estimates with those measured from five retrieved implants. Additionally, these models were used to assess the role of assembly technique—one-hit versus three-hits—on the taper interlock mechanical behaviour. Results. The model compared well to deformed microgrooves from the retrieved implants, predicting changes in microgroove height (mean 1.1 μm (0.2 to 1.3)) and width (mean 7.5 μm (1.0 to 18.5)) within the range of measured changes in height (mean 1.4 μm (0.4 to 2.3); p = 0.109) and width (mean 12.0 μm (1.5 to 25.4); p = 0.470). Consistent with benchtop studies, our model found that increasing assembly load magnitude led to increased taper engagement, contact pressure, and permanent deformation of the stem taper microgrooves. Interestingly, our model found assemblies using three hits at low loads (4 kN) led to decreased taper engagement, contact pressures and microgroove deformations throughout the stem taper compared with tapers assembled with one hit at the same magnitude. Conclusion. These findings suggest additional assembly hits at low loads lead to inferior taper interlock strength compared with one firm hit, which may be influenced by loading rate or material strain hardening. These unique models can estimate microgroove deformations representative of real contact mechanics seen on retrievals, which will enable us to better understand how both surgeon assembly techniques and implant design affect taper interlock strength. Cite this article: Bone Joint J 2020;102-B(7 Supple B):33–40

Infections are the most uneventfull complications after tumor resection and implantation of a maegaendopros-thesis.Silver-coating of megaendoprosthesis has become a regular procedure in our department since last year in tumor cases. Especially in revision cases with high risk of infection they play a major role in preventing adhesion of bacteria. The successful reduction in infection rates show the effectiveness of the coating but still leave the question “how much coating do we need?” and “how much coating can be tolerated. Latest research concentrated on the coating of the stems, since they can still be the source of the infection if everything else is coated by silver already. Summarised so far, our experience in a rabbit model, a phase I Trial in humans and prelimnary results in Phase II Trials in humans showed no toxic side effects. Driven so far it seems to be sensible to extent the silver coating. So far, the coating is limited to all areas without joint movement or bone contact. An Animal trial was performed anylising the osteointegrative properties of an silver-coated stem versus an regular Titanium stem in 17 dogs. After 12 months of regular X-Ray Analysis a Pull-out test and a concentration analysis has been done. Results showed high significantly (p< 0.001) an osteointegration in 8 out of 8 titanium stems with an average pull-out force of 3764 Newton (Range 1755– 5967 Newton). Silver-coated stems showed no signs of Osteointegration in all 9 out of 9 femurs. The average pull-out force was 21 Newton (Range 0– 186 Newton). A cemented control could resist a pull out force of 350 Newton. Analysis of the silver concentration directly in the first millimeter of the bone-implant interface and the second millimeter showed highly elevated silver levels. The silver concentration in the bone-implant interface at Titanium stems ranged from 0.3 to 3502 parts per Billion (ng/g) compared to silver-coated stems ranging from 303 to 2.418.800 ppb parts per Billion (ng/g). Discussion: Sharing the histologic picture and reactions of the osteoblasts to the silver-coating there are several possible reasons for failed osteointegration. We want o discuss wether these has to be considered as a toxic response or just an adverse reaction. In summary, surgeons have to decide in the future how much silver they need in each individual case concerning intramedullary infection prophylaxis. The balance between loosening or infection should be based on long term expectations, taking into account that even after successful resection of a tumor an ongoning infection can lead to loosening of a limb or even life. Apart from intramedullary use, we recommend silver as a safe adjuvant therapy in all suited patients undergoing endoprosthetic reconstruction after tumor resection

Introduction. Adverse local tissue reactions (ALTR) can result in devastating soft tissue and osseous destruction, while potentially increasing the risk of concomitant periprosthetic joint infection (PJI). The aims of this study were to evaluate cobalt (Co) and chromium (Cr) levels generated in simulators from metal-on-polyethylene (MoP) and ceramic-on-polyethylene (CoP) constructs, and determine their impact on native tissues and PJI risk through evaluation of human adipose-derived mesenchymal stem cells (AMSCs) and Staphylococcus epidermidis isolates. Methods. Ten hip simulator constructs were assembled with 36-mm high-offset femoral heads, highly cross-linked polyethylene liners, and titanium stems. Five constructs used CoCr femoral heads and five used ceramic. Constructs were submerged in bovine serum (BS) and run for 1,000,000 cycles. Samples of BS were collected and evaluated for CoCr concentration. Various concentrations of CoCr were chosen for further assessment of cytotoxicity and growth impact on AMSCs and S. epidermidis and compared to inert SiO2. Results. After 1,000,000 cycles, mean MoP and CoP Co concentration was 2264 ng/mL and 0.6 ng/mL, respectively (p<0.001). Mean MoP and CoP Cr concentration was 217 ng/mL and 4.3 ng/mL, respectively (p<0.001). Mean MoP Co:Cr ratio was 10. Co nanoparticles were significantly more toxic to human AMSCs than control SiO2 in a dose-response manner (p<0.001). S. epidermidis growth was not significantly impacted by Co concentrations derived from the simulators. Conclusions. MoP constructs built in ideal conditions generated substantial CoCr debris, highlighting a baseline risk with these implants that may be exacerbated by host factors or imperfect surgical technique. Evaluation of impact on AMSCs suggests that debris levels produced under ideal conditions can be cytotoxic. Additionally, these concentrations did not potentiate or inhibit S. epidermidis growth, suggesting elevated PJI rates with ALTR may be related to other factors potentially associated with tissue necrosis. For any tables or figures, please contact the authors directly

12 patients requiring revision of a cemented Furlong total hip replacement had advanced corrosion of their titanium femoral stems. Thigh pain unlike that of loosening was a characteristic feature of presentation an average 38 months after implantation (range 20–58 months). Radiographs demonstrated fusiform periosteal thickening of the middle and distal thirds of the femur around the prosthetic stem with variable amounts of osteolysis around the tip. None of the femoral stems showed evidence of loosening and in 9 cases revision was solely for recurrent atypical pain. The titanium stems were retrieved at an average 80 months (range 60–113). All were well-fixed but showed signs of advanced corrosion distally with blackened stems, loss of surface metal and thick white deposits. Two stems were examined with scanning electron microscopy and energy dispersive X-ray analysis. Micromotion abrasions were identified proximally with loss of all alloy constituents. Distally, there was selective loss of titanium in a pattern suggestive of crevice corrosion. This may be accelerated by a galvanic effect if a cobalt chromium head is mixed with a titanium stem. After revision to an all stainless steel femoral stem and head, early follow-up demonstrates resolution of both symptoms and radiological abnormalities at an average 13 months (range 3–33) from revision. Conclusion: Once stem debonding has set up crevice conditions around a femoralimplant, the cement layer prevents repassivation (oxidation) of the metal surface upon which titanium depends for its stability. We therefore caution against the use of a titanium alloy stem with cementation, the conclusion of at least one other similar series. We also believe that the combination of cobalt chromium and titanium alloys is unsafe as, contrary to some of the published work on the subject, depassivated titanium is prone to galvanic attack in this situation

Introduction. Stress shielding of bone around the stem components of total shoulder replacement (TSR) implants can result in bone resorption, leading to loosening and failure. Titanium is an ideal biomaterial for implant stems; however, it is much stiffer than bone. Recent advances in additive manufacturing (AM) have enabled the production of parts with complex geometries from titanium alloys, such as hollow or porous stems. The objective of this computational study is to determine if hollow titanium stems can reduce stress shielding at the proximal humerus. We hypothesize that hollow TSR implant stems will reduce stress shielding in comparison with solid stems and the inner wall thickness of the hollow stem will be a design parameter with a direct effect on bone stresses. Methods. Using a previously developed statistical shape and density model (SSDM) of the humerus based on 75 cadaveric shoulders, a simulated average CT image was created. Using MITK-GEM, the cortical and trabecular bones were segmented from this CT image and meshed with quadratic tetrahedral elements. Trabecular bone was modeled as an isotropic and inhomogeneous material, with the Young's modulus defined element-by-element based on the corresponding CT densities. Cortical bone was assumed isotropic with a uniform Young's modulus of 20 GPa. The Poisson's ratio for all bone was 0.3. The distal humerus was fully constrained. Bone stresses were calculated by performing finite element analyses in ABAQUS with a 320 N force and 2 Nm frictional moment applied to the articular surface of the humeral head, based on an in vivo study during 45 degrees of shoulder abduction. Subsequently, the humeral head was resected and reamed to receive solid- and hollow-stemmed implants with identical external geometries but three different inner wall thicknesses (Figure 1). The identical surrounding bone meshes for the intact and reconstructed bones allowed element-by-element stress comparisons. The volume-weighted average changes in cortical and trabecular bone von Mises stresses were calculated, (wrt the intact humerus), as well as the percentage of bone volume experiencing a relative increase or decrease in stress greater than 10%. Results. Results for all four implant designs are summarized (Figure 2). The solid stem resulted in the biggest average change in von Mises stresses (4% decrease in cortical and 6% increase in cancellous bone stress). The solid stem also resulted in the largest volume of bone experiencing a decrease in stress. Comparing the hollow stems, the thinnest shell wall resulted in the smallest changes in cortical bone stress, and the lowest volumes of bone experiencing a decrease in stress. Interestingly, this design caused the most cancellous bone to experience an increase in stress. Discussion. These results suggest a marginal improvement in the bone-implant mechanics of hollow versus solid stems, and that thinner shell walls perform better. That said, the improvements over the solid stem design are minimal. Further increasing the compliance of these stems, e.g. by adding pores, may improve their performance. Future work will focus on optimizing hollow and porous stem designs, and the possibility of leveraging their hollow design for drug delivery. For any figures or tables, please contact the authors directly

Early failures have seen titanium fall from favour as a material for cemented femoral stems. Between 1989 and 1994, we performed a prospective review of a consecutive series of 122 cemented total hip replacements using the Ultima straight textured titanium stem, and report the five- to ten-year clinical and radiological outcomes. There were no revisions for loosening of the femoral stem. Revision surgery was undertaken for other reasons such as dislocation, infection and loosening of the cup in 7.3%. Of those patients without revision all but two were satisfied with their hip, with 74% graded good or excellent using a modified Harris hip score. Radiological assessment revealed probable loosening in two. Although slight vertical subsidence was found in one-third of patients it had not progressed to loosening. It is not clear whether this represents debonding. Non-progressive radiolucent lines (1 to 2 mm) were present in zone 1 at the cement-prosthesis interface in 14.7%. Calcar resorption and hypertrophy around the distal stem were not often seen. With 97% survival at a mean of 7.5 years, the medium-term results of this specific cemented titanium stem are reassuring so far, but we are concerned about debonding and future failure

Aims. There are limited published data detailing the volumetric material loss from tapers of conventional metal-on-polyethylene (MoP) total hip arthroplasties (THAs). Our aim was to address this by comparing the taper wear rates measured in an explanted cohort of the widely used Exeter THA with those measured in a group of metal-on-metal (MoM) THAs. Patients and Methods. We examined an existing retrieval database to identify all Exeter V40 and Universal MoP THAs. Volumetric wear analysis of the taper surfaces was conducted using previously validated methodology. These values were compared with those obtained from a series of MoM THAs using non-parametric statistical methodology. A number of patient and device variables were accounted for using multiple regression modelling. Results. A total of 95 Exeter MoP and 249 MoM THAs were examined. The median volumetric loss from the MoM cohort was over four times larger than that from the MoP cohort (1.01 mm. 3. vs 0.23 mm. 3. , p < 0.001), despite a significantly shorter median period in vivo for the MoM group (48 months vs 90 months, p < 0.001). Multiple regression modelling indicated that the dominant variables leading to greater female taper material loss were bearing diameter (p < 0.001), larger female taper angles (p < 0.001), and male titanium stem tapers (p < 0.001). Conclusion. Consistent with the long-term clinical success of the device, the volumetric material loss from Exeter femoral head tapers was, in general, small compared with that from larger-diameter MoM head tapers. Cite this article: Bone Joint J 2018;100-B:1310–9

Introduction. We have investigated the long-term (minimum follow-up period; 10 years) clinical results of the total hip arthroplasty (THA) using K-MAX HS-3 tapered stem. Materials and Methods. In K-MAX HS-3 THA (Kyocera Medical, Kyoto, Japan), cemented titanium alloy stem and all polyethylene cemented socket are used. This stem has the double tapered symmetrical stem design, allowing the rotational stability and uniform stress distribution. The features of this stem are; 1. Vanadium-free high-strength titanium alloy (Ti-15Mo-5Zr-3Al), 2. Double-tapered design, 3. Smooth surface (Ra 0.4µm), 4. Broad proximal profile, 5. Small collar. Previous type stem, which was made of the same smooth-surface titanium alloy, has the design with cylindrical stem tip, allowing the maximum filling of the femoral canal. Osteolysis at the distal end of the stem had been reported in a few cases in previous type with cylindrical stem tip, probably due to the local stress concentration. Therefore the tapered stem was designed, expecting better clinical results. 157 THAs using HS-3 taper type stem were performed at Kitano Hospital between March 2004 and March 2008. And 101 THAs, followed for more than 10 years, were investigated (follow-up rate; 64.3%). The average age of the patients followed at the operation was 61.7 years and the average follow-up period was 10.9 years. The all-polyethylene socket was fixed by bone cement, and the femoral head material was CoCr (22mm; 5 hips, 26 mm; 96 hips). Results. Two hips were revised, one was due to late infection, and the other due to breakage of the implant in trauma. Japanese orthopaedic association (JOA) score improved from 40 to 86 points. Postoperative complication was three periprosthetic fractures (one femoral shaft fracture and two greater trochanteric fractures) and femoral shaft fracture case was operated. Dislocation was not observed. Socket loosening (Hodgkinson, Type 3, 4) and stem loosening (Harris, definite and probable) were not observed radiographically. Cortical hypertrophy was observed in 7.9%. The survival rate of HS-3 tapered stem was 98% for revision due to any reason and 100% for revision due to aseptic loosening. Discussion. The long-term clinical results of K-MAX HS-3 tapered stem were excellent. The osteolysis at the stem tip was not observed in this type, which was observed in a few cases in previous type. From the X-ray finding, it was suggested that this taperd stem had more uniform stress distribution to the femoral bone than previous type. Moreover, the problems associated with titanium alloy usage were not observed. From the present investigation, good farther long-term results of the tapered titanium stem were expected

Summary. Particulate wear debris with different chemical composition induced similar periprosthetic tissue reactions in patients with loosened uncemented and cemented titanium hip implants, which suggests that osteolysis can develop independent of particle composition. Introduction. Periprosthetic osteolysis is a serious long-term complication in total hip replacements (THR). Wear debris-induced inflammation is thought to be the main cause for periprosthetic bone loss and implant loosening. The aim of the present study was to compare the tissue reactions and wear debris characteristics in periprosthetic tissues from patients with failed uncemented (UC) and cemented (C) titanium alloy hip prostheses. We hypothesised that implant wear products around two different hip designs induced periprosthetic inflammation leading to osteolysis. Patients & Methods. Thirty THR-patients undergoing revision surgery were included: Fifteen patients had loose cemented titanium stems (Titan. ®. , DePuy) and 15 had well-fixed uncemented titanium stems (Profile, DePuy), but loose or worn uncemented metal-backed cups with conventional UHMWPE liners (Gemini, Tropic and Tri-Lock Plus, DePuy; Harris/Galante and Trilogy, Zimmer). A semi-quantitative histological evaluation was performed in 59 sections of periprosthetic tissues using light microscopy. Wear particles were counted by polarised light and high resolution dark-field microscopy. Additionally, particle composition was determined by SEM-EDXA following particle isolation using an enzymatic digestion method. Blood metal ions were determined with high resolution-ICP-MS. Results. The implants in the uncemented group were revised after a median of 15.7 years (range: 7.25–19.3) due to osteolysis and high wear of the polyethylene liner and metal backing resulting in gross metallosis, and/or cup loosening. The average lifetime of implants in the cemented group was only 6.5 years (range: 1.5–11.75) due to early stem loosening with large osteolysis pockets in the femur close to the cement mantle. Tissue examination revealed similar results for both groups: numerous mononuclear histiocytes and chronic inflammatory cells, a few neutrophils and multinucleated giant cells, and to some extent necrosis. The amount of metal particles per histiocyte positively correlated with the tissue reactions in the cemented, but not in the uncemented group. A higher particle load (medians: C: 14727 vs. UC: 1382 particles/mm. 2. , p<0.0001) was found in tissues adjacent to cemented stems, which contained mainly submicron ZrO. 2. particles. Particles containing pure Ti or Ti alloy elements (size range: 0.21 to 6.46 µm) were most abundant in tissues from the uncemented group. Here, also PE was more frequent, but accounted only for a small portion of total particles (2.8 PE/mm. 2. ). The blood concentrations of titanium (range: 3.8–138.5 microgram/L) and zirconium (cemented cases, range: 0.6–3.5 microgram/L) were highly elevated in cases with high abrasive wear and metallosis. Discussion/Conclusion. Phagocytosis of different wear particles by histiocytes induced a similar chronic inflammatory reaction in the periprosthetic tissues in both groups. ZrO. 2. particles, originating from bone cement degradation, dominated in the cemented group, while in the uncemented group the high abundance of pure Ti and Ti alloy particles of various sizes indicates wear of the metal-backed cups. The low density of polyethylene particles in the tissues suggests that they are not solely responsible for the tissue reactions and accompanying osteolysis. Our findings suggest that the chemical composition of wear particles plays a minor role in the mechanism of osteolysis. Particle size, load and ionic exposure might be more important

Aims. Dual mobility (DM) implants have been shown to reduce the dislocation rate after total hip arthroplasty (THA), but there remain concerns about the use of cobalt chrome liners inserted into titanium shells. The aim of this study was to assess the clinical outcomes, metal ion levels, and periprosthetic femoral bone mineral density (BMD) at mid-term follow-up in young, active patients receiving a modular DM THA. Methods. This was a prospective study involving patients aged < 65 years, with a BMI of < 35 kg/m. 2. , and University of California, Los Angeles activity score of > 6 who underwent primary THA with a modular cobalt chrome acetabular liner, highly cross-linked polyethylene mobile bearing, and a cementless titanium femoral stem. Patient-reported outcome measures, whole blood metal ion levels (μg/l), and periprosthetic femoral BMD were measured at baseline and at one, two, and five years postoperatively. The results two years postoperatively for this cohort have been previously reported. Results. A total of 43 patients were enrolled. At minimum follow-up of five years, 23 (53.4%) returned for clinical and radiological review, 25 (58.1%) had metal ion analysis performed, 19 (44.2%) underwent dual energy x-ray absorptiometry scans, and 25 (58%) completed a pain-drawing questionnaire. The mean modified Harris Hip Scores improved significantly from 54.8 (SD 19) preoperatively to 93.08 (SD 10.5) five years postoperatively (p < 0.001). One patient was revised for aseptic acetabular loosening. The mean cobalt levels increased from 0.065 μg/l (SD 0.03) to 0.08 (SD 0.05) and the mean titanium levels increased from 0.35 (SD 0.13) to 0.78 (SD 0.29). The femoral BMD ratio decreased in Gruen Zone 1 (91.9%) at five years postoperatively compared with the baseline scores at six weeks potoperatively. The femoral BMD ratio was maintained in Gruen zones 2 to 7. Conclusion. The use of a modular DM component and a cementless, tapered femoral stem shows excellent mid-term survivorship with minimal concerns for corrosion and metal ion release in a cohort of young, active patients undergoing primary THA. Cite this article: Bone Joint J 2021;103-B(7 Supple B):73–77

There has been an evolution in revision hip arthroplasty towards cementless reconstruction. Whilst cemented arthroplasty works well in the primary setting, the difficulty with achieving cement fixation in femoral revisions has led to a move towards removal of cement, where it was present, and the use of ingrowth components. These have included proximally loading or, more commonly, distally fixed stems. We have been through various iterations of these, notably with extensively porous coated cobalt chrome stems and recently with taper-fluted titanium stems. As a result of this, cemented stems have become much less popular in the revision setting. Allied to concerns about fixation and longevity of cemented fixation revision, there were also worries in relation to bone cement implantation syndrome when large cement loads were pressurised into the femoral canal at the time of stem cementation. This was particularly the case with longer stems. Technical measures are available to reduce that risk but the fear is nevertheless there. In spite of this direction of travel and these concerns, there is, however, still a role for cemented stems in revision hip arthroplasty. This role is indeed expanding. First and foremost, the use of cement allows for local antibiotic delivery using a variety of drugs both instilled in the cement at the time of manufacture or added by the surgeon when the cement is mixed. This has advantages when dealing with periprosthetic infection. Thus, cement can be used both as interval spacers but also for definitive fixation when dealing with periprosthetic hip infection. The reconstitution of bone stock is always attractive, particularly in younger patients or those with stove pipe canals. This is achieved well using impaction grafting with cement and is another extremely good use of cement. In the very elderly or those in whom proximal femoral resection is needed at the time of revision surgery, distal fixation with cement provides a good solution for immediate weight bearing and does not have the high a risk of fracture seen with large cementless stems. Cement is also useful in cases of proximal femoral deformity or where cement has been used in a primary arthroplasty previously. We have learnt that if the cement is well-fixed then the bond of cement-to-cement is excellent and therefore retention of the cement mantle and recementation into that previous mantle is a great advantage. This avoids the risks of cement removal and allows for much easier fixation. Stems have been designed specifically to allow this cement-in-cement technique. It can be used most readily with polished tapered stems - tap out a stem, gain access at the time of revision surgery and reinsert it. It is, however, now increasingly used when any cemented stems are removed provided that the cement mantle is well fixed. The existing mantle is either wide enough to accommodate the cement-in-cement revision or can be expanded using manual instruments or ultrasonic tools. The cement interface is then dried and a new stem cemented in place. Whilst the direction of travel in revision hip arthroplasty has been towards cementless fixation, particularly with tapered distally fixed designs, the reality is that there is still a role for cement for its properties of immediate fixation, reduced fracture risk, local antibiotic delivery, impaction grafting and cement-in-cement revision

The use of short femoral components in primary total hip arthroplasty (THA) represents an attractive option. Advocates tout bone preservation and ease of use in less invasive surgical approaches. In 2006 we adopted the concept and have had experience with over 5,700 short, tapered, titanium, porous plasma-sprayed stems in patients undergoing primary THA. The plasma-sprayed portion of this stem is similar to the longer, standard length TaperLoc stem, with shortening resulting from a 3 cm reduction in length of the distal portion of the implant. However, the proximal aspect maintains the same flat, tapered wedge proximal geometry as the standard stem. During insertion in some femurs it was noted that distal canal fill occurred preferentially to proximal canal fill. This required distal broaching in order to accommodate a larger stem. In an effort to avoid this clinical situation and to improve the gradual off-loading that is the goal of a tapered geometry, the design was modified in 2011 to reduce the profile of the component. Other modifications include a lower caput-collum-diaphyseal (CCD) angle to enhance horizontal offset restoration without increasing leg length, width sizing from 5–18 mm in 1 mm increments, and polished neck flats to increase range of motion. Undoubtedly, porous plasma sprayed tapered titanium stems are successful in primary THA. Short stems can better accommodate proximal-distal femoral mismatch, particularly in hips with a large metaphysis and a narrow diaphysis, hips with an excessively bowed femur, and hips with severe deformity such as that encountered with developmental dysplasia and post-traumatic arthritis. Short stems violate less femoral bone stock, allowing for more favorable conditions should revision surgery become necessary. The concept of a short stem is appealing to patients, who perceive it as less invasive. In addition, short stems facilitate shorter incision surgery and operative approaches such as the muscle-sparing anterior supine intermuscular. Increased canal fill has been associated with distal cortical hypertrophy. Reducing the distal portion of the stem has reduced the incidence of distal canal fill, and allows for placement of a slightly larger implant

Introduction. Modular-neck hips have twice the rate of revision compared to fixed stems. Metal related pathology is the second most common reason for revision of implants featuring titanium stems with cobalt chrome necks. We aimed to understand the in-vivo performance of current designs and explore the rationale for their continued use. Methods. This study involved the examination of 200 retrieved modular-neck hips grouped according to the material used for their neck and stem. Groups A, B and C had neck/stems featuring CoCr/beta Ti-alloy (TMZF), CoCr/Ti6Al4V-alloy, and Ti6Al4V/Ti6Al4V respectively. Reasons for revision included pain, elevated metal ion levels and fluid collection. The stem-neck interface was assessed for severity of fretting/corrosion using metrology methods to compute linear wear penetration rate. Results. All retrieved implants with a CoCr/Ti combination showed evidence of moderate-severe fretting corrosion at the neck-stem junction. Maximum penetration depth rate in group A (median of 17.9μm/year) was higher than that in group B (median=5.8μm/year); p=0.0012 and group C (median=1.55μm/year), p=0.0095. Implant failure occurred 2-fold earlier in modular-neck hips with TMZF-alloy stems than Ti6Al4V. There was a strong correlation between severity of damage and time to revision in the TMZF group A (p < 0.0001) and between taper damage and Co levels (p < 0.0001) and Cr levels (p < 0.0012). Patient and implant data did not correlate with the amount of material loss observed, (p>0.05). Discussion. The findings are in agreement with registry data as designs with CoCr/Ti at neck/stem interfaces had the highest levels of fretting and corrosion and lower threshold for revision. Conclusion. Corrosion of metal orthopaedic implants remains of clinical concern to patients, surgeons and industry. In light of the findings, the continued use of modular-neck with a metal mismatch at the neck/stem junction is unfavourable and should be avoided

Tapered, fluted, modular, titanium stems have a long history in Europe and are increasing in popularity in North America. We have reviewed the results at our institution looking at stem survival and clinical outcomes. Radiological outcomes and quality of life assessments have been performed and compared to cylindrical non-modular cobalt chromium stems. Survival at five years was 94%. This fell to 85% at ten years due to stem breakage with older designs. Review of radiology showed maintenance or improvement of bone stock in 87% of cases. Outcome scores were superior in tapered stems despite worse pre-operative femoral deficiency. Tapered stems have proved to be a useful alternative in revision total hip arthroplasty across the spectrum of femoral bone deficiency

Aims. To evaluate the hypothesis that failed osteosynthesis of periprosthetic Vancouver type B1 fractures can be treated successfully with stem revision using a transfemoral approach and a cementless, modular, tapered revision stem with reproducible rates of fracture healing, stability of the revision stem, and clinically good results. Patients and Methods. A total of 14 patients (11 women, three men) with a mean age of 72.4 years (65 to 90) undergoing revision hip arthroplasty after failed osteosynthesis of periprosthetic fractures of Vancouver type B1 were treated using a transfemoral approach to remove the well-fixed stem before insertion of a modular, fluted titanium stem which obtained distal fixation. These patients were clinically and radiologically followed up for a mean 52.2 months (24 to 144). Results. After a mean of 15.5 weeks (standard deviation (. sd. ) 5.7) all fractures had healed. No stems subsided and bony-ingrowth fixation had occurred according to the classification of Engh et al. The mean Harris Hip Score increased from a pre-operative score of 22.2 points (. sd. 9.7) to 81.5 points (. sd. 16.8) 24 months post-operatively. All hips had obtained an excellent result according to the classification of Beals and Tower. Conclusions. The technique described here for stem revision provides reproducibly good results in the treatment of failed osteosynthesis for Vancouver types B1 periprosthetic fractures of the hip. Cite this article: Bone Joint J 2017;99-B(4 Supple B):11–16

Peri-prosthetic femoral fracture after total hip replacement (THR) is associated with a poor outcome and high mortality. However, little is known about its long-term incidence after uncemented THR. We retrospectively reviewed a consecutive series of 326 patients (354 hips) who had received a CLS Spotorno replacement with an uncemented, straight, collarless tapered titanium stem between January 1985 and December 1989. The mean follow-up was 17 years (15 to 20). The occurrence of peri-prosthetic femoral fracture during follow-up was noted. Kaplan-Meier survival analysis was used to estimate the cumulative incidence of fracture. At the last follow-up, 86 patients (89 hips) had died and eight patients (eight hips) had been lost to follow-up. A total of 14 fractures in 14 patients had occurred. In ten hips, the femoral component had to be revised and in four the fracture was treated by open reduction and internal fixation. The cumulative incidence of peri-prosthetic femoral fracture was 1.6% (95% confidence interval 0.7 to 3.8) at ten years and 4.5% (95% confidence interval 2.6 to 8.0) at 17 years after the primary THR. There was no association between the occurrence of fracture and gender or age at the time of the primary replacement. Our findings indicate that peri-prosthetic femoral fracture is a significant mode of failure in the long term after the insertion of an uncemented CLS Spotorno stem. Revision rates for this fracture rise in the second decade. Further research is required to investigate the risk factors involved in the occurrence of late peri-prosthetic femoral fracture after the implantation of any uncemented stem, and to assess possible methods of prevention

Aims

There are limited long-term studies reporting on outcomes of the Zimmer Modular Revision (ZMR) stem, and concerns remain regarding failure. Our primary aim was to determine long-term survival free from all-cause revision and stem-related failure for this modular revision stem in revision total hip arthroplasty (THA). Secondary aims included evaluating radiological and functional outcomes.

Introduction. Modular dual mobility (MDM) prostheses are increasingly utilized for total hip arthroplasty (THA) to mitigate the risk of postoperative instability in high risk patients. Short-term reports on clinical outcomes are favorable but there are few studies on young active patients. This study quantified proximal femoral stress shielding and metal ion release in MDM combined with modern cementless stem design in young active patients. Methods. This was a prospective study of patients between 18 and 65 years of age, with a body mass index (BMI) < 35 kg/m2 and University of California at Los Angeles (UCLA) activity score > 6, who received a modular cobalt-chromium acetabular liner, highly crosslinked polyethylene mobile bearing, and cementless titanium femoral stem for their primary THA. DEXA scans were performed at 6 weeks postoperatively as a baseline, then again at 6 months, 1 year, 2 years and 5 years postoperatively as were metal ions. Results. A total of 43 patients (30 male, 13 female; mean age 52.6 years (sd 6.5)) were enrolled. At the time of analysis, 14 patients had completed DEXA scans at 5 years postoperatively. There was no significant loss of proximal femoral bone mineral density in Gruen Zones 1–7 or acetabular bone mineral density in Gruen Zones 1–6 between 6 weeks and 5 years postoperatively (p > 0.05 for each zone). Sixteen patients had metal ions at 5yrs. Cobalt levels averaged .07 ppb (range .012 – .451) and chromium levels averaged 0.24 ppb (range .092 – .883). Conclusion. At a minimum 5 years follow up, MDM with a modern cementless stem demonstrated minimal stress shielding and no concerning metal ion release in young active patients

Introduction. Mechanically assisted crevice corrosion (MACC) in metal-on-polyethylene (MOP) total hip arthroplasty (THA) is of concern, but its prevalence, etiology and natural history are incompletely understood. Methods. From January 2003 to December 2012, 1356 consecutive THA surgeries using a titanium stem, cobalt chromium alloy femoral head, highly crosslinked polyethylene and a tantalum or titanium acetabular shell were performed. Patients were followed at 1 year, and 5 year intervals for surveillance, but also seen earlier if they had symptoms. Any patient with osteolysis or unexplained pain underwent exam, radiographs, CBC, ESR and CRP, as well as serum cobalt (Co) and chromium (Cr) level. MARS MRI was performed if the Co level was > 1 ppb. Results. Symptomatic MACC was present in 39/1356 patients (2.9%). Yearly MACC prevalence ranged from 0 % (0/139, 2005) to 9.9 % (16/162, 2009). 22/39 (56%) patients have undergone revision surgery, and 17/39 (44%) have opted for ongoing surveillance. Of the surveillance patients, serial serum metal ion levels appear to increase over time. Time of symptoms is correlated with tissue necrosis at time of revision. Conclusions. The prevalence of MACC in MOP hips is higher in this cross-sectional study than previously reported. The highest prevalence was found in 2009 with this vendor. Based on how common this finding is in symptomatic patients from 2009, we may consider asking asymptomatic patients to obtain baseline serum ion levels. The goal of our ongoing research is to understand how to avoid permanent soft tissue loss from adverse local tissue reactions caused by MACC

The femoral diaphysis presents the best opportunity for fixation during revision THA. Both fully coated cylindrical and modular fluted tapered titanium stems have demonstrated excellent results. Cylindrical stems have demonstrated concerning rates of failure when used in larger, osteopenic canals or in canals with post-isthmal divergent morphologies. Modular stems offer the advantage of separating distal fixation needs from proximal version, leg length, and offset needs via a modular junction. Although early designs demonstrated some breakages at the taper or through thin proximal bodies, newer generation implants have not demonstrated such mechanical concerns. Additionally, the modular junctions do not appear to be having any problems with corrosion. Mid- to long-term data with various designs now support the safety and efficacy of these constructs that can handle a wide variety of challenges during femoral revision. Careful attention to detail is necessary to minimise the risk of subsidence and intra-operative fracture or femoral perforation

There is a paucity of available literature to guide the surgeon treating postoperative fractures of the greater trochanter after femoral component revision. Between 2009 and 2016, 133 patients underwent femoral component revision by the senior author utilizing a modular tapered fluted titanium stem. 17 patients died or had inadequate follow-up. Therefore, 116 patients were included in the final analysis. There were 58 males and 58 females with a mean age of 64 (range 23 to 91 years old). Clinical and radiographic data were analyzed for postoperative greater trochanteric fracture (GTfx). Mean clinical follow up was 21 months (range 3 to 77 mos). Age, BMI, preoperative diagnosis, comorbidities, reason for revision, use of Extended Trochanteric Osteotomy (ETO), fixation method of ETO, presence of prior hardware, post-operative trauma (falls), femoral component size and offset, change in leg length were analyzed to determine potential risk factors for postoperative GT fracture. There were 7 postoperative greater trochanteric fractures in 7 patients (6%). Of these, 1 occurred as a result of a postoperative fall, 1 occurred after dislocation, and 1 occurred after a fall with a subsequent dislocation. The mean time to diagnosis of the fracture was 10.7 weeks postoperatively (range one day to 37.4 weeks). 52 of 116 patients had their revision performed through an ETO. Of those, 6 had a postoperative fracture of the GT. The use of an ETO significantly increased the likelihood of postoperative GT fx (p=0.035). Regarding femoral component size, use of a longer proximal body (+10 or greater) was associated with an increased risk of postoperative GT fx (p=0.07). Two fractures were minimally (<1cm) or non-displaced and were treated non-operatively. Of these fractures, 1 united. The other fracture further displaced and resulted in recurrent instability. This was treated with excision of the fragment and a constrained liner. 5 fractures were displaced and were treated with ORIF. 3 were fixed with a cable grip device, 1 was plated, and 1 was treated with a cable grip device and a constrained liner. Of those treated with some form of ORIF, all 5 healed. Of those that underwent surgical fixation initially, 3 reported residual trochanteric pain and 1 patient had their hardware removed (trochanteric claw). 2 of these patients have a residual limp and require a cane for use as a gait aid. The patient treated non-surgically required a cane as did the patient that failed non-surgical treatment. Post-operative greater trochanteric fractures are a rare complication of femoral component revision. The use of an ETO significantly increased the rate of post of GTfx. The mean time to diagnosis of was 11 weeks. Displaced fractures of the greater trochanter treated with ORIF all healed, both cable grip devices and plates were effective. Residual limp requiring gait aids and residual trochanteric pain were common outcomes after fixation of these fractures despite successful union

This study was conducted to evaluate the clinical and radiographic results on titanium stems that were similar in design but differed with regard to proximal grit-blasted surface texture with and without a hydroxy-apatite (HA) coating. We evaluated 40 patients who had undergone primary total hip replacement by a postero-lateral approach. The stems, all made of titanium alloy, tapered, grit-blasted, collarless, with anterior-posterior fins, did present some differences: in a group of 20 stems a proximal hydroxyapatite coating (thickness: 50 μm) was implanted; in another group of 20 stems the proximal surface was without HA coating. Clinical and radiographic evaluations were performed pre-operatively at 3, 6 and 12 mounths during the first year; than once for the following years.The mean duration of follow-up was 6 years. At the final follow-up examination the Harris hip scores in the HA-coated group (mean, 96 points) and non-HA coated group (mean, 94 points) were similar. Bone-remodelling patterns were similar in the groups and the fast bone integration of the HA coated group. In both groups only two cases of aseptic loosening of the stems were found. After 6 years of follow-up, the clinical and radiographic results among grit-blasted titanium tapered stems with or without Ha coating were perfectly similar. The optimum final bone integration was due just to the singular shape of femur (type B Dorr’s) with an excellent proximal bone stock. The micromotion of implants reduced the bony-anchored stems in two cases

Aims

The aim of this study was to evaluate medium- to long-term outcomes and complications of the Stanmore Modular Individualised Lower Extremity System (SMILES) rotating hinge implant in revision total knee arthroplasty (rTKA) at a tertiary unit. It is hypothesized that this fully cemented construct leads to satisfactory clinical outcomes.

The December 2023 Hip & Pelvis Roundup³⁶⁰ looks at: Early hip fracture surgery is safe for patients on direct oral anticoagulants; Time to return to work by occupational class after total hip or knee arthroplasty; Is there a consensus on air travel following hip and knee arthroplasty?; Predicting whether patients will achieve minimal clinically important differences following hip or knee arthroplasty; High-dose dual-antibiotic-loaded cement for hip hemiarthroplasty in the UK (WHiTE 8): a randomized controlled trial; Vitamin E – a positive thing in your poly?; Hydroxapatite-coated femoral stems: is there a difference in fixation?

The vast majority of total-joint-replacement components utilized are modular to some degree. Modularity increases the surgeon’s options in both primary and revision THA. Modular prostheses allow the surgeon intra-operative versatility, allowing adjustment of leg length, offset, neck length, and version. This is particularly helpful in CHD, posttraumatic arthritis and in hip revision. Modularity may be applied also to the neck, enlarging the range of choice for difficult cases. Howeverusing of a modular interface increases risk of fretting, wear debris, and dissociation and mismatching of components. A series of 87 revision THA performed between 1997 and 2003 using modular neck was reviewed. The pros-theses are AnCA-Fit with a cementless titanium anatomical stem and Profemur with a tapered revision titanium stem. Both provided with a modular neck inserted by morse taper and a hemispheric press-fitted cup. All the implants have a ceramic-ceramic coupling. Four cases were performed due to recurrent dislocation and 83 for implant loosening. Retrieved necks were studied searching for corrosion. No cases of disassembly or fracture of the neck were observed. Two cases of dislocation were treated with brace. Analysis of retrieved necks confirmed the absence of corrosion. Leg length discrepancy decreased from 57.7% to 22%. One post-operative infection was successfully treated with debridment. Modular neck system allows to correct intraoperatively leg length and offset, choosing between five interchangeable necks available in two lengths: straight, varus-valgus, ante-retroverted. Restoration of hip biomechanics prevents instability. Removal of the neck allows a better surgical exposure when femoral stem is retained. Moreover it allows to maintain ceramic-ceramic coupling. Modular prosthesis has some problems related to risk of corrosion, fretting, fracture or dislocation of components. We observed no cases of disassembly of components or fracture and comparative analysis between retrieved necks and those experimentally studied confirmed absence of corrosion

Cementless stem fixation is a widely used method of stem revision in North America and elsewhere in the world. There is abundant literature in its support. Most of the reports from 1985 to 2005 related to proximally or extensively porocoated designs, the former falling into disfavor with time because of unpredictable outcomes. With few exceptions (e.g. S-ROM) the modularity of these designs was limited to the head/neck junction. But this generation of designs was associated with some issues such as insertional fractures, limited control of anteversion (and risk of dislocation), limited applicability in the setting of severe bone loss (Paprosky Type 4 osteolysis or Vancouver Type B3 periprosthetic fracture), as well as ongoing concern relating to severe proximal stress shielding. In the past decade we have seen the mounting use of a new design concept: tapered fluted titanium stems (TFTS), which incorporate the advantages of titanium (for less flexural rigidity), conical taper (for vertical taper-lock stability), longitudinal ribs or flutes (for rotational stability), and surface preparation which attracts bone ongrowth for long term fixation. Four consecutive reports from our center have documented the superiority of the TFTS in our hands, with encouraging outcomes even when dealing with severe bone loss or periprosthetic fractures. There is an increasing body of other literature which reports a similar experience. Furthermore, with increasing experience and confidence in this design concept, we now use a monoblock or non-modular design in the majority of cases in which a TFTS is indicated. This circumvents the potential drawbacks of stem modularity, including taper corrosion and taper junction fracture. Our recent report of this concept in 104 cases with a 2-year minimum follow-up supports the use of this concept in many if not most stem revisions. The question remains as to which should be favored? Because of equipoise in the outcomes of the two fundamental stem designs, at least in our hands, clearly the surgeon needs to ask other, more practical questions:. Am I familiar enough with the TFTS technique so as to bypass the potential versatility of the modular stem for the simplicity and potential cost savings of the non-modular?. Is this a case in which modularity will offer me distinct advantages (periprosthetic fracture, and severe bone loss as examples). Should I introduce the nonmodular TFTS to my practice, choosing straightforward cases first; ones in which I would comfortably and with confidence use an extensively porocoated stem?

A-70-year old woman underwent uncomplicated total hip arthroplasty using a titanium modular stem with a 46mm CoCr femoral head, a titanium shell, and a metal linear (Wright Medical Technology). Eight years after implantation, she presented with a painful left hip. A pelvic radiograph revealed adequate positioning of both hip implants without any signs of wear of loosening. CT scanning confirmed the presence of a 5 × 5 cm soft tissue mass in the ilium above the cup component accompanied by the iliac fracture. The patient was diagnosed as having an adverse reaction to metal debris (ARMD) after a metal-on-metal THA and revision was performed. Perioperatively?tissue necrosis and partial destruction of the abductor mechanism were found in the absence of any macroscopic infection. Both the neck trunnion and bore of the head showed slight signs of corrosion. The modular neck was revised with a ceramic 28mm head and a new dual-mobility liner(Zimmer Biomet). The iliac fracture was fixed with a porous trabecular metal augment(Zimmer Biomet). The histopathology of tissue sample revealed extensively necrotic material with focal cellular areas of inflammatory cells containing macrophages and neutrophilas. Metalic debris was also scattered in the necrotic materials. After the revision, the patient was recovered without pain or dislocation, and iliac fracture was well fixed. Instability is a substantial problem in the revision of ARMD. Extensive necrosis with gross deficiency of the abductor mechanism is associated with postoperative dislocation. Revision of failed MoM THA a dual-mobility device an effective strategy

Revision of the failed femoral component can be challenging. Multiple reconstructive options are available and the procedure is technically difficult and thus meticulous pre-operative planning is required. The Paprosky Femoral Classification is useful as it helps the surgeon determine what bone stock is available for fixation and hence, which type of femoral reconstruction is most appropriate. Type 1 Defect: This is essentially a normal femur and reconstruction can proceed as the surgeon would with a primary femur. Type 2 Defect: The metaphysis is damaged but still supportive and hence a stem that gains primary fixation in the metaphysis can be used. Type 3 Defect: The metaphysis is damaged and non-supportive and hence a stem that gains primary fixation in the diaphysis is required. Broken down into types “A” and “B” based on the amount of intact isthmus available for distal fixation. Type 3A Defect: >4 cm of intact femoral isthmus is present. Can be managed with a fully porous coated stem, so long as the diameter is <18 mm and torsional remodeling is not present. Type 3B Defect: There is < 4 cm of intact femoral isthmus and based on lower rates of osseointegration if a fully porous coated stem is used, a modular titanium tapered stem is recommended. Type 4 Defect: The most challenging to manage as there is no isthmus available for distal fixation. Can be managed with proximal femoral replacement if uncontained and impaction grafting if contained. We have also successfully used modular titanium tapered stems that appear to gain “3-point fixation” in this type of defect

Objectives. The use of ceramic femoral heads in total hip arthroplasty (THA) has increased due to their proven low bearing wear characteristics. Ceramic femoral heads are also thought to reduce wear and corrosion at the head-stem junction with titanium (Ti) stems when compared with metal heads. We sought to evaluate taper damage of ceramic compared with metal heads when paired with cobalt chromium (CoCr) alloy stems in a single stem design. Methods. This retrieval study involved 48 total hip arthroplasties (THAs) with CoCr V40 trunnions paired with either CoCr (n = 21) or ceramic (n = 27) heads. The taper junction of all hips was evaluated for fretting/corrosion damage and volumetric material loss using a roundness-measuring machine. We used linear regression analysis to investigate taper damage differences after adjusting for potential confounding variables. Results. We measured median taper material loss rates of 0.210 mm. 3. /year (0.030 to 0.448) for the metal head group and 0.084 mm. 3. /year (0.059 to 0.108) for the ceramic group. The difference was not significant (p = 0.58). Moreover, no significant correlation between material loss and implant or patient factors (p > 0.05) was found. Conclusions. Metal heads did not increase taper damage on CoCr trunnions compared with ceramic heads from the same hip design. The amount of material released at the taper junctions was very low when compared with available data regarding CoCr/Ti coupling in metal-on-metal bearings. Cite this article: A. Di Laura, H. Hothi, J. Henckel, I. Swiatkowska, M. H. L. Liow, Y-M. Kwon, J. A. Skinner, A. J. Hart. Retrieval analysis of metal and ceramic femoral heads on a single CoCr stem design. Bone Joint Res 2017;6:–350. DOI: 10.1302/2046-3758.65.BJR-2016-0325.R1

Tapered, fluted, modular, titanium stems are increasingly popular in the operative management of Vancouver B2 and selected B3 peri-prosthetic femoral fractures. We have reviewed the results at our institution looking at stem survival and clinical outcomes and compared this with reported outcomes in the literature. Stem survival at a mean of 54 months was 96% in our series and 97% for combined published cases. Review of radiology showed maintenance or improvement of bone stock in 89% of cases with high rates of femoral union. Favourable clinical outcome scores have reported by several authors. No difference in survival or clinical scores was observed between B2 and B3 fractures. Tapered stems are a useful option in revision for femoral fracture across the spectrum of femoral bone deficiency. Cite this article: Bone Joint J 2013;95-B, Supple A:17–20

Introduction. We have compared the middle-term (average follow-up period; 10 years) clinical results of the K-MAX HS-3 tapered stem with those of the previous type having cylindrical tip. Materials and Methods. In K-MAX HS-3 THA (Kyocera Medical, Kyoto, Japan), cemented titanium alloy stem and all polyethylene cemented socket are used. This stem has the double tapered symmetrical stem design, allowing the rotational stability and uniform stress distribution (Type T) (Fig. 1). The features of this stem are; 1. Vanadium-free high-strength titanium alloy (Ti-15Mo-5Zr-3Al), 2. Double-tapered design, 3. Smooth surface (Ra 0.4μm), 4. Broad proximal profile, 5. Small collar. In contrast, previous type stem, which was made of the same smooth-surface titanium alloy, has the design with cylindrical stem tip, allowing the maximum filling of the femoral canal (Type C) (Fig. 2). Osteolysis at the distal end of the stem had been reported in a few cases in Type C, probably due to the local stress concentration. Therefore the tapered stem was designed, expecting better clinical results. All surgery was performed at Kitano Hospital between September 2003 and June 2006. 72 THA were performed (Type T; 52 hips, Type C; 20 hips). The average age of the patients at the operation was 61 and 69 years and the average follow-up period was 10.1 and 10.4 years for the Type T and C, respectively. The all-polyethylene socket was fixed by bone cement, and the femoral head material was alumina or CoCr (22 or 26 mm). Results. One hip was revised in Type C. Japanese orthopaedic association (JOA) score improved from 39/37 to 84/77 points (Type T/C). Postoperative complication was dislocation in one case (Type C; 1). Socket loosening was not observed radiographically. Stem loosening was observed in one hip in Type C, demonstrating osteolysis at the distal end of the stem. In this case, revision THA was performed 3.5 years postoperatively. Bone resorption was more frequently observed in Type C than Type T. Cortical hypertrophy was observed in 7.7% in Type T and 25% in Type C. Discussion. The middle-term clinical results of K-MAX HS-3 taper stem (Type T) was excellent. The osteolysis at the stem tip was not observed in this type, which was observed in a few cases in previous Type C. From the X-ray finding, it was suggested that Type T had more uniform stress distribution to the femoral bone than Type C. Moreover, the problems associated with titanium alloy usage were not observed. From the present investigation, good long-term results of the tapered titanium stem (Type T) was expected. For any figures or tables, please contact authors directly (see Info & Metrics tab above).

Peri-prosthetic fractures of the femur around a THA remain challenging injuries to treat. The Vancouver Classification helps to guide decision making, and is based on fracture location, implant fixation status, and remaining bone quality. It is critical to determine fixation status of the implant, even if surgical dislocation is necessary. Type A fractures involve the trochanters, and are usually due to osteolysis. Revision of the bearing surface and bone grafting of the lesions can be effective. Type B1 fractures occur around a well fixed stem, typically at the stem tip. Internal fixation with laterally based locked cable plates is effective. Optimising proximal fixation is important, typically with locked screws and cables. Allograft struts are probably unnecessary with modern angle stable plates. Type B2 and B3 fractures are treated with revision, either with a fully coated cylindrical or a modular fluted tapered titanium stem. Distal fixation should be optimised, while preserving vascularity to proximal bony fragments. The « internal scaffold » technique has been described with excellent results. Rarely, a proximal femoral replacement is necessary. Careful attention to detail and clear knowledge of stem fixation status is necessary for a good outcome

Aims

This study reports the ten-year wear rates, incidence of osteolysis, clinical outcomes, and complications of a multicentre randomized controlled trial comparing oxidized zirconium (OxZr) versus cobalt-chrome (CoCr) femoral heads with ultra-high molecular weight polyethylene (UHMWPE) and highly cross-linked polyethylene (XLPE) liners in total hip arthroplasty (THA).

Introduction and Aims: This paper presents a treatment plan for femoral stem revision that has been developed based on long-term studies of revision total hip replacement (THR) using cemented stems, cementless proximal fixation stems, cemented stems with impaction grafting and modular titanium long stems. Method: The clinical and radiographic results of femoral stem revision were compared using the following techniques: 1) a standard or long cemented collarless double taper Exeter or CPT stems (CCDT stems) [n=190]; 2) a proximally porous coated mid to long cementless stem [n=56]; 3) two series of CCDT stems with impaction grafting n=34]; and 4) a modular grit-blasted titanium taper stem [n=13] used for severe cortical damage. Treatment decisions were made based on the age of the patient, the appearance of the pre-operative radiograph and the extent of bone deficiency at surgery. Follow-up was from 17 to two years. Results: Only one hip was lost to follow-up. In the CCDT group, at a median follow-up of five years (range 2–17 years), two standard length stems and one long stem had been re-revised for loosening (1.5%) and seven stems had been re-revised for other reasons. Survivorship to re-revision for loosening at eight years was 95% (95%CI=85–100%) for both standard and long stems. There was a trend for better longer-term results for long stems. The extent of pre-operative bone loss did not influence results. For the cementless proximal fixation group, at a median follow-up of 10 years, re-revision of the stem for loosening occurred in 20%. Importantly, these poor results could have been predicted from short-term results. The initial series of femoral impaction grafting with CCDT stems and irradiated bone had a small incidence of stem loosening and periprosthetic fracture. The majority of stems subsided, but at a median follow-up of eight years there were no further re-revisions. In the second series, usually with non-irradiated allograft with mesh containment, there was minimal stem subsidence and no re-revision. The grit blasted titanium taper stem has dealt with periprosthetic fratures and severe proximal cortical loss, but with some cases of subsidence and femoral fracture. Conclusion: Based on these results, our treatment plan for routine femoral revision in middle-aged and elderly patients without severe proximal deficiency is a polished CCDT long stem. In younger patients, impaction grafting is recommended, provided deficient bone is protected. Cementless modular stems are reserved for femurs with severe proximal cortical deficiency

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

Aims

The aim of this study was to analyze how proximal radial neck resorption (PRNR) starts and progresses radiologically in two types of press-fit radial head arthroplasties (RHAs), and to investigate its clinical relevance.

Aims

This study aimed to assess the carbon footprint associated with total hip arthroplasty (THA) in a UK hospital setting, considering various components within the operating theatre. The primary objective was to identify actionable areas for reducing carbon emissions and promoting sustainable orthopaedic practices.

Cementless stem fixation is a widely used method of stem revision in North America and elsewhere in the World. There is abundant literature in its support. Most of the reports from 1985 to 2005 related to proximally or extensively porocoated designs, the former falling into disfavor with time because of unpredictable outcomes. With few exceptions (eg S-ROM) the modularity of these designs was limited to the head/neck junction. But this generation of designs was associated with some issues such as insertional fractures, limited control of anteversion (and risk of dislocation), limited applicability in the setting of severe bone loss (Paprosky Type 4 osteolysis or Vancouver Type B3 periprosthetic fracture), as well as ongoing concern relating to severe proximal stress shielding. In the past decade we have seen the mounting use of a new design concept: tapered fluted titanium stems (TFTS), which incorporate the advantages of titanium (for less flexural rigidity), conical taper (for vertical taper-lock stability), longitudinal ribs and flutes (for rotational stability), and surface preparation which attracts bone on growth for long term fixation. Four consecutive reports from our center have documented the superiority of the TFTS in our hands, with encouraging outcomes even when dealing with severe bone loss or periprosthetic fractures. There is an increasing body of other literature which reports a similar experience. Furthermore, with increasing experience and confidence in this design, we now use a monoblock or non-modular design in greater than 95% of cases in which a TFTS is indicated at our center. This circumvents the potential drawbacks of stem modularity, including taper corrosion and taper junction fracture

Introduction. Failure of the neck-stem taper in one particular bi-modular primary hip stem due to corrosion and wear of the neck piece has been reported frequently1, and stems were recalled. A specific pattern of material loss on the CoCr neck-piece taper in the areas of highest stresses on the proximal medial male taper was observed in a retrieval study of 27 revised Rejuvenate implants revised after 3 to 38 month time in situ (Stryker, Kalamazoo, MI, USA) (Figure 1). One neck piece exhibited additionally wear marks at the distal end of the flat male neck taper indicating contact with the female taper of the stem. The purpose of this study was to understand the observed failure scenario of bottoming-out by investigating the stem taper morphologies. Materials and Methods. The geometry of taper contact surfaces was determined using a Coordinate Measurement Machine (BHN 805, Mitutoyo, Japan). An algorithm based on the individual unworn areas of the respective taper surfaces was applied to all retrievals. One retrieval is additionally investigated by infinite focus microscopy (G4, Alicona, Austria) in the main wear areas on the neck piece taper, and the bottom, facing each other inside the junction (surfaces of the distal end of the male and the bottom of the female taper). Results. The bottom of the male neck piece taper showed a prominent patch surrounded by a corrosion area (Figure 2), similar to the pattern observed in the proximal taper articulation medial- proximally and lateral-distally (Figure 1). The bottom of the female titanium stem taper did not show material loss to this extent, but only slight scratches. The proximal male taper of the neck piece showed the usual corrosion pattern, with an elevated patch protruding inside the corrosion cavity (Figure 3, left). Contrarily to observations on other retrievals (Figure 3, right), the height of this patch did not reach the original surface level. The wear depth at the patch of the bottomed out taper was 93µm with wear reaching as deep as 170µm. Discussion. Only one of 27 retrieved neck pieces showed bottoming out. It can be speculated that the other retrievals were revised before this situation could occur. In the assembled situation, the initial space between the bottom faces of the stem taper is expectedly in the order of a few 100µm. During the observed wear process, permanent contact at patches on the neck piece prevents its reseating, until these localized structures give in to mechanical and electrochemical exposure. This end stage of failure only occurring in one explant indicates high clinical risks of the implants during earlier stages of intact patches, that are usually observed in retrievals. The formation of such patches has not been reported before, and might be characteristic for the wear and corrosion mechanism of the employed TMZF-CoCr combination, possibly due to the reduced stiffness of the TMZF Titanium. Acknowledgements. The research received funding from the European Union's Seventh Framework Program (FP7/2007-2013) under grant agreement GA-310477 (LifelongJoints)

Introduction. Modular hip replacement systems use Morse tapers as an interlocking mechanism to connect ball heads to femoral stems. Even though this interlocking mechanism generally performs successfully for decades, failures due to disassociation of the ball head from the stem are reported in the literature. Therefore, this failure mechanism of a possible loosening is usually evaluated in the course of the development of femoral stems. The disassembly force is a possible parameter to characterize the strength of the interlocking mechanism. Thus, the aim of the current study was to examine the impact of different taper parameters on the disassembly force of ceramic ball heads from titanium stem tapers by finite element studies. Materials and Methods. A 2D axisymmetric finite element model was developed to simulate the disassembly procedure. First ball head and taper were assembled with a force of 4 kN. Afterwards the system was unloaded to simulate the settlement. Disassembly was simulated displacement controlled until no more adhesion between ball head and taper occurred. Isotropic elastic material behavior was modelled for the ceramic ball head while elastic-plastic material behavior was modelled for the titanium taper. Different angular gaps (0.2°, 0.15°, 0.1°, 0.05°, 0°, −0.05°, −0.1°) and different taper topography parameters regarding groove depth (12, 15 µm), groove distance (210, 310 µm) and plateau width (1, 5, 10, 20 µm) were examined. Frictional contact between ball head and taper was modelled. Results. The topography of the taper (groove depth, distance and plateau width) within the investigated range had only a small impact on the disassembly force (Fig. 1) while the varying angular gaps had a large effect (Fig. 2). Decreasing disassembly forces were found for decreasing angular gaps. For the negative angular gaps (i.e. male taper angle > female taper angle) the forces increased. The same trends were found for the sliding distance (sliding along the tangential direction in the taper region), deformation of the grooves and contact stresses. Reciprocal behavior was found for the contacting area. Discussion. Surface topography seems to have only minor influence, while macro-geometry seems to have major impact on the disassembly force. Higher disassembly forces are associated with smaller contacting areas, higher contact stresses, larger deformations of the grooves and larger sliding distances. For a negative angular gap the maximum stresses of the ceramic component were found at the taper mouth. This could be disadvantageous since the wall thickness in this region of the ball heads decreases and critical hoop stresses could increase the risk of a fracture. The decrease in contacting areas due to the extreme angular gaps could promote corrosive effects since a larger taper area is exposed to fluid. Furthermore, the higher contact stresses and groove deformations could increase taper wear. Therefore, a general examination of possible influencing factors and cross effects on the in vivo performance have to be conducted during the development of femoral stems. Future studies will include a wear model and include 3D calculations to examine more realistic loading scenarios. To view tables/figures, please contact authors directly

Introduction. Mechanically-assisted corrosion of the head-neck junction present a dilemma to surgeons at revision THR whenever the femoral component is rigidly fixed to the femur. Many remove the damaged femoral head, clean the femoral taper and fix a new head in place to spare the patient the risks associated with extraction and replacement of the well-functioning femoral stem. This study was performed to answer these research questions:. Will new metal heads restore the mechanical integrity of the original modular junction after impaction on corroded tapers?. Which variables affect the stability of the new interface created at revision THR?. Materials and Methods. Twenty-two tapers (CoCr, n=12; TiAlV, n=10) were obtained for use in this study. Ten stems were in pristine condition, while 12 stems had been retrieved at revision THR and with corrosion damage to the trunnion (Goldberg scale 4). Twenty-two new metal heads were obtained for use in the study, each matching the taper and manufacturer of the original component. The following test states were performed using a MTS Machine: 1. Assembly, 2. Disassembly, 3. Assembly, 4. Toggling and 5. Disassembly. All head assemblies were performed wet using 50% calf serum in accordance to ISO 7206-10. During toggling, each specimen's loading axis was aligned 25° to the trunnion axis in the frontal plane and 10° in the sagittal plane (Figure 1). Toggling was performed at 1Hz for 2,000 cycles with a sinusoidal loading function (230N–4300N). During loading, 3D motion of the head-trunnion junction was measured using a custom jig rigidly attached to the head and the neck of each prosthesis. Relative displacement of the head with respect to the neck was continuously monitored using 6 high resolution displacement transducers with an accuracy of ±0.6µm. Displacement data was independently validated using FEA models of selected constructs. Results. The average micromotion of the head vs trunnion interface was greatest at the start of loading and stabilized after approximately 50 loading cycles at an average of 30.6±3.2µm (Figure 2). For CoCr couples, interface motion dropped by 17% when a pristine head was mounted on a corroded stem compared to a new stem (25.7±2.7µm (pristine stem), vs. 30.1±4.6µm (corroded stem), p= 0.4023) (Figure 3). However, addition of a new CoCr head with a corroded titanium stem led to an 73% increase in interface motion after assembly with a new CoCr head (Corroded: 43.4±9.8µm, Pristine: 25.2±7.0µm, p=0.1661). The resistance to head-neck disruption was 15% higher in TIALV/CoCr couples compared to CoCr/CoCr (TiAlV: 2558 ±63N, CoCr: 2226±99N, p=0.0111) and was not affected by the presence of corrosion of the trunnion (1% loss of strength in each case). Discussion. Corrosion at the trunnion does not disrupt the mechanical integrity of the junction when a CoCr head is replaced on a CoCr taper. We are less sure about the mechanical integrity of a TiAlV taper demonstrated by a trend towards increased micromotion at this junction. Further work is required to better elucidate the role of dissimilar metals in the mechanical integrity of the head-neck junction

To document the medium term results of the use of a fluted tapered titanium femoral stem in revision total hip arthroplasty. 70 patients undergoing total hip revision using a tapered grit blasted titanium modular stem were reviewed at a mean follow up time of 47 months. No bone graqfts were used. Femoral defects were classified according to Pak and Paprosky and the femoral bone quality was assessed with the Bohm and Bischel system. Clinical function was assessed by the Oxford Hip Score. Radiographic analysis was performed in all cases. The results of the use of this prosthesis compares favourably with other revision stems. The Oxford Hip Scores compare favourably with the results for revisions recorded in the New Zealand National Joint Register (24.3) Although technically demanding this stem offers a very satisfactory solution for revision of total hips in most circumstances

Revision after failed femoral components may be technically demanding due to loss of peri-prosthetic bone. This retrospective study evaluated the long-term results of femoral revision using the cementless Wagner Self-Locking stem. Between 1992 and 1998, 68 consecutive hips in 66 patients underwent femoral revision using this implant. A total of 25 patients died from unrelated causes without further revision; the remaining 41 hips in 41 patients (12 men and 29 women) with a mean age of 61 years (29 to 80) were reviewed at a mean follow-up of 13.9 years (10.4 to 15.8). A transfemoral approach was used in 32 hips. A total of five stems required further revision because of infection in two, progressive subsidence in two and recurrent dislocation in one. Four hips had dislocated and eight stems had subsided ≥ 10 mm. The mean Harris hip score improved from 33 points pre-operatively to 75 points at final follow-up (p < 0.001). In all, 33 stems (91.7%) showed radiological signs of stable bone fixation. The cumulative survival rates at 15.8 years with femoral revision for any reason and for stem failure as the endpoints were 92.0% (95% confidence interval (CI) 86.0% to 98.4%) and 96.6% (95% CI 92.2% to 100%), respectively. The survivorship with revision and ≥ 10 mm migration of the stem as the endpoint was 83.6% (95% CI 76.6% to 91.4%). This study shows quite good survival and moderate clinical outcome when using a monoblock tapered titanium stem for supporting the regeneration of bone in complex revision hip surgery.

Introduction: Intramedullary cementless fixation of massive tumor prostheses was developed to combat the high incidence of aseptic loosening in a young population of tumor patients. Its use has also expanded to include reconstruction of failed major knee arthroplasty. Our system uses a hydroxyapatite coated titanium stem in conjunction with a hydroxyapatite collar to obtain fixation. Methods: We present a series of 72 patients (34 females, 38 males) with a mean follow-up of six years (2 months – 14 years). The mean age at the time of surgery was 17 (5 – 77). Within this group, 51 patients had osteosarcomas, 10 had giant cell tumors, eight had Ewing’s sarcoma and one each had malignant fibrous histiocytoma, spindle cell sarcoma and failed total knee arthroplasty. Non-invasive and minimally invasive growing prostheses were used in 33 patients. Results: Nine patients required revision of the prosthesis at a mean of 5.2 years; 5 for aseptic loosening and four for infection. Twelve patients died at a mean of 20 months (1 – 84) post-operatively. Radiological evidence demonstrated remodelling around both the stem and the collar. There was gap closure to the hydroxyapatite coated collar in cases where seating was not complete. Consistent loss of cortical bone around the mid-stem was noted in the first 12 months but remained stable beyond this time frame. Discussion: This study highlights our experience with cementless distal femoral endosprostheses. We demonstrate good results with regard to revision rate, gap closure and osseointegration

Introduction. Large diameter metal-on-metal hip arthroplasty (LDMMTHA) provides benefits of reduced dislocation rates and low wear. The use of modular systems allows better restoration of hip biomechanics. There have been reports of modular LDMMTHAs with tapered sleeves generating excessively high metal ions, due to possible mismatch between the titanium stem and the cobalt-chrome sleeve and the dual Morse tapers involved. We evaluated metal ion levels in LDMMTHA patients with and without a cobalt-chrome (CoCr) tapered sleeve. Methods. A cross-sectional series of 91 patients with proximal porous titanium alloy stem LDMMTHA with identical design CoCr bearings, attending a 1 to 2-year review were assessed with routine clinical and radiographic examinations, hip scores and metal ion analysis. Of these 65 had a single Morse taper between monoblock CoCr heads and the stems. Twentysix had a tapered cobalt-chrome sleeve in addition, with the resultant dual taper. Mean bearing diameter was 46 mm in both groups and mean age was 58 years in the monoblocks and 66 years in the tapered sleeve group. Results. Mean Oxford Hip score is worse in the tapered group (14.7) than in the monoblocks (12.6). All patients had well-functioning hips clinically and radiologically. Median blood cobalt and chromium are higher in the tapered sleeve (2.3μg/L and 1.8 μg/L) compared to the monoblocks (1.8 μg/L and 1.1 μg/L). Urine cobalt and chromium levels in the tapered sleeve (13.8 μg/24 hr and 5.3 μg/24 hr) also are higher than those in the monoblocks (12.2 μg/24 hr and 4.5 μg/24 hr respectively). Discussion and Conclusion. The limitation of this study is that it is a cross-sectional study. The results indicate that the use of a tapered sleeve in total hip arthroplasty does lead elevation of cobalt and chromium levels and the difference is statistically significant. However these levels are not as high as the levels reported with some other hip systems which have been withdrawn and the clinical significance of the elevated levels in the present study is unknown

Purpose: The long term exposure to metal ions released from metal-metal articulations is worrying. Studies have shown comparable ion level between metal-metal HR and 28mmTHA. No study has analyzed the amount of ion released from LDH-THA. We compared the amount of ion released from HR and LDH-THA from the same manufacturer. Method: Whole-blood concentrations of Cobalt was measured prospectively (pre op, 3, 6, 12, 24 months) with HR-ICPMS in 74 HR and 54 LDH-THA with the same metal bearing characteristics and acetabular component (monoblock Cobalt-Chrome with titanium plasma-spray coating). The femoral head of LDH-THA was inserted on a titanium stem with a Cobalt-Chrome adapter sleeve to adjust offset and leg length. Results: Demographic data was similar. The pre op Cobalt level (ug/L) were 0.10 vs. 0.11, 3 months 0.90 vs. 0.84, 6 months 0.90 vs. 1.28, 12 months 0.68 vs.1.75, and 24 months 0.56 (5.6X preop level) vs. 1.82 (16.5X preop level) in the HR and LDH-THA groups, respectively. The cobalt level decreased after 6 months in HR, whereas it was still increasing at 2y with LDH-THA. Conclusion: In order to reduce wear and ion release from metal-metal bearing, most manufacturers focus research on improvements at the bearing surfaces. This study has shown that the simple addition of a sleeve with 2 modular junctions can results in a dramatic increase in ion release, diminishing the value of improvements made at the bearing surface. The total amount of ion released from a metal-metal implant should be considered globally and as such, better modular taper designs should be developed

In 80 patients with a mean age of 50 years, 97 uncemented primary THAs were performed using a titanium stem with a proximal circumferential plasma spray coating. Three different acetabular components were used, in 70% of cases a threaded and partly porous-coated design. At a mean follow-up of 8 years, two femoral components had been revised. One stem was revised 103 months after insertion owing to a comminuted fracture of the proximal femur, and one 104 months after insertion owing to deep infection. There were no stem revisions for aseptic loosening. We calculate the probability of survival of the femoral component at 0.98%. Sixteen acetabular components (14 threaded cups) had been revised in 13 patients. One femur had areas of distal osteolysis, associated with verified deep infection, but no signs of proximal loosening. Three femora had areas of minor proximal osteolysis. The mean Harris hip score at the latest follow-up was 91 points. We conclude that an uncemented titanium femoral component with a proximal circumferential plasma spray coating is an excellent option in THA in the young patient. As reported previously, aseptic loosening of threaded acetabular components was common

We have developed bioactive bone cements manufactured from bioactive glass-ceramic powder and BIS-GMA resin, which has the bone-bonding ability. In the present clinical trial, this bioactive bone cement was used for fixation of total hip arthroplasty (THA) and the clinical results were investigated. Two types of bioactive bone cements (high- and low- viscosity type cements) were prepared (Nippon Electric Glass Co. Ltd.). Inorganic filler contained 72.0 wt% AW-GC (apatite and wollastonite containing glass-ceramic) and 27.0 wt% SiO2 powder. All surgery was performed at Kyoto University Hospital between February and October 1996. 20primary THA (20 patients) were performed using bioactive bone cement as a clinical trial. The average age of the patients was 58 years. The average follow-up period was 6 years, 9 months. The diagnosis for 18 hips at the operation was osteoarthritis and 2 hips were rheumatoid arthritis. All sockets and one stem were fixed by bioactive cement, and all but one stem were fixed by PMMA cement. In all cases all polyethylene socket and titanium stem were used (14 KC type THA and 8 KMAX type THA). For the femoral head 22 mm diameter alumina head was used in all cases. If the bone cement is bioactive and shows direct bonding with the bone, wear particles can’t enter the interface and thus prevention of loosening due to bone resorption would be expected. This cement demonstrated satisfactory clinical results, proving to be a promising material for implant fixation

In 85 % of the patients with rheumatoid arthritis the MCP-joints are involved with incressing deterioration an loss of function. The standard replacement of the MCP-joints using the Swanson-Silastic Spacers shows pain reduction and a realigment of the fingers, but the functional capacity is not improved. The HM-MCP-arthroplasty offers a concept for better function an restoration of the rheumatoid hands and osteoarthritis. In a prospective multicenter study 63 HM-MCP arthroplasties have been implanted. We used the redesigned model (PE-metacarpal head and Ti-ODH phalangeal base) with titanium stems. The follow up-time is 18 months (6 – 40 months). All patients are controlled with clinical and radiographic evaluation. The active ROM of the MCP-joints demonstrated on average flex./ext. 65/10/0 (preop. 70/15/0). The grip strength at FU demonstrated 80 % of the untreated contralateral control hand. Pain has been improved using the verbal pain scale at 1.6 (preop. 2.1). Radiographically all metacarpal and phalangeal stems show an osteointegration of the implants. Radio-lucent lines of < 1 mm have been detected at the phalangeal base without a sign of loosing. Complications: 1 palmar luxation with a successful closed reposition, 1 ulnar subluxation of the fifth finger, 1 unsuccessful revised palmar luxation. The results of the uncemented, unconstrained HM-MCP-arthroplasty show an improvement of the hand function and pain reduction. This endoprosthesis gives a new chance to treat the rheumatoid hand at an earlier stage of destruction before severe contracture of the soft tissues

Aims: A polyethylene free, metal on metal acetabular system (Hofer-Imhof cup; Lubrimet metal on metal articulation made of CoCr-forge alloy) was designed in an effort to improve total hip arthroplasty longevity. This study was undertaken to review the clinical performance of this implant and to determine if acetabular loosening or revision and wear and osteolysis were prevalent. The long term results (mean follow up period 110 months) are presented in this study. Methods: In this prospective, randomized study a minimum of 90 months follow up results involving the first 100 implanted metal liner total hip arthroplasties are presented. The mean follow up was 110 months. Between April 1995 and November 1996 ninety-eight patients (100 hips) had a total hip replacement consisting of a titanium cementless self reaming, parabolic cup, a cementless titanium stem and the Lubrimet® metal on metal articulation. Two acetabular and one femoral component had to be revised due to aseptic loosening without showing macroscopic evidence of metallosis and no histological evidence of excessive metal wear. One patient hat to be revised by a complete change of the total hip (acetabular component and stem) showing histologic evidence of a metal induced hyperergic immunologic reaction. One patient presented with a broken neck of the stem and had to be revised by stem exchange. As a none device related orthopedic complication one acetabular component required revision surgery due to a periprosthetic fracture. Conclusions: The long term results of the Hofer-Imhof Lubrimet®Metal-on-metal articulation are satisfying and so the system represented a viable alternative for total hip arthroplasty in younger higher demand patients in the past. Due to the possible development of a hyperergic immunologic reaction to the metal on metal articulation and the availibility of a ceramic on ceramic articulation we do not implant this liner anymore

Revision THA is guaranteed to throw some light on the question of longevity of implants. This study takes a fresh look at the materials that we have used in 30 years of joint replacement. We studied four consecutive revision arthroplasties performed in one week. Patient 1 was a 55-year-old woman who in 1994 received a titanium-backed acetabular cup with virgin HDP insert and an alumina femoral head on a titanium stem. Polyethylene osteolysis was obvious and histological assessment confirmed the presence of polyethylene granulomata. Patient 2 was a 28-year-old man who had bilateral ceramic-on-ceramic hip replacements 18 and 19 years previously. The prosthesis on the left became loose and showed a typical alumina-ceramic problem. Patient 3 was a 51-year-old woman with stage-III polyethylene disease after 19 years. Substantial granulomata were seen on histological sections. Patient 4, a 52-year-old woman, had received a gamma cross-linked cup and stainless steel head 22 years previously. She presented with dislocation but no tribological problems. There was no wear and interfaces were perfect. These four cases highlight the importance of proper selection of tribological materials. Polyethylene disease was an important cause of medium-term or late failure and acrylic debris was only a secondary problem. Literature reports on titanium metallosis seem over-rated, but titanium performance is questionable with cement. Finally, cross-linking of ultra-high molecular weight polyethylene is a simple, cheap and effective way of enhancing long-term performance in joint replacement surgery

Aims: A polyethylene free, metal on metal acetabular system (Hofer-Imhof cup; Lubrimet¨ metal on metal articulation made of CoCr-forge alloy) was designed in an effort to improve total hip arthroplasty longevity. This study was undertaken to review the clinical performance of this implant and to determine if early ace-tabular loosening or revision and wear and osteolysis were prevalent. The mid term results (mean follow up period 62,7 months) are presented in this study. Methods: In this prospective, randomized study a minimum of 55 months follow up results involving the þrst 100 implanted metal liner total hip arthroplasties are presented. The mean follow up was 62,7 months. Between April 1995 and November 1996 ninety-eight patients (100 hips) had a total hip replacement consisting of a titanium cementless self reaming, parabolic cup, a cementless titanium stem and the Lubrimet¨ metal on metal articulation. 98 patients (100 hips) had complete clinical and radiographic data 55 to 89 months after the operation. One acetabular and one femoral component had to be revised due to aseptic loosening without showing macroscopic evidence of metallosis and no histological evidence of excessive metal wear. As a none device related orthopedic complication one acetabular component required revision surgery due to a peri-prosthetic fracture. Conclusions: The mid-term results of the Hofer-Imhof Lubrimet¨Metal-on-metal articulation are encouraging and so the system may represent a viable alternative for total hip arthroplasty in younger higher demand patients

Aims: to evaluate the process of remodelling at the bone-femoral prosthesis interface by using computerized bone mineralometry (CMB)Methods: at the Orthopaedic Clinic, University Catania we performed from January 1992 densitometric studies on uncemented, anatomically shaped, titanium stems with or without hydroxyapatite (HA) coating. Dual energy X-ray densitometry was used to quantify bone mineral concentration and bone mineral density (BMD). Measurements were performed at the calcar and the medial and lateral cortical of the femur which have been previously demonstrated to be areas of stresses transmission in the normal hip. From 1992 to 2001, 148 patients were regularly studied. 76 subjects had a HA-coating stem. Evaluation was performed at 3, 6 and 12 months after operation and then yearly. Results: in all patients a minimal remodeling process (BMD values > 1 gr/cm. 2. ) was observed at the medial cortical and the calcar zones. We noted higher BMD values in the group with HA-coating stem within 24 months after the operation; BMD values were overlapping between the two groups after 24 months. 27 subjects had reduced densitometric values at the calcar and increased BMD at medial and lateral cortical. Conclusions: CMB appears to be a reliable tool to evaluate the interaction at the bone-femoral prosthesis interface. Densitometric values might be helpful to monitor the periprosthetic bone-remodelling process

Aims: We have been alerted due to a high and early failure rate in total hip arthroplasties using metal-on-metal (Metasul?) bearings. Investigation on retrieved bearings at revision surgery should lead us to causes for early failures. Methods: 135 primary total hip arthroplasties in 118 patients (28 women and 90 men) with Metasul¨ bearing were implanted between 1992 and 1998. The mean age at implantation was 55 years (range, 29 to 84). In 105 cases a cementless MŸller SL cup and in 30 cases a MŸller Reinforcement Ring was used. Twelve out of 105 cases with a þne blasted SL cup needed a revision surgery after 34.9 months (range, 13 to 59). Qualitative histology was performed in all cases, quantitative metal analysis took place in two cases. The wear rate of the heads and their insert was measured and compared to former studies. Bony cylinders taken from the acetabular roof prior to primary implantation were histologically analyzed and compared to cup migration studies (EBRA). Results: Four cups and seven cemented titanium stems with tight cups were loose. In one case with polyarthritis both components had to be replaced. In one patient with cup loosening an impingement between neck and cup was found. In two patients histology showed diminution of bone-stock and in two cases no bony integration was observed. Conclusions: From twelve revision cases, we found only one where the metal-metal bearing is clearly responsible for the revision surgery. Metal-on-metal articulation seems to be promising if the component orientation is correct

Aims: To investigate whether the use of mini-spigots result in enhanced wear and corrosion of tapers compared to standard spigots and the influence of the surface finish on this. Methods: The heads were cobalt chrome and the stems titanium alloy. Firstly wear and corrosion of standard spigots were compared with mini-spigots and secondly, these mini-spigots with another mini-spigot with a smoother surface finish. The samples were immersed in aerated Ringers solution (37°C) and loaded for 10 million cycles. Then samples were sectioned and the surface parameters measured and interfaces investigated using scanning electron microscopy. Static corrosion tests were used under loaded and non-loaded conditions and pitting tests for non-loaded samples. Results: Pre-experimentation the surfaces of the female tapers were similar for all heads. At the end of the first test the surface parameters on the female tapers had become significantly greater (p=0.034) for the mini-spigots compared with standard spigots and an abrupt change noted on the surface profile of the female taper where it contacted the male taper, indicating that the cobalt chrome head had corroded. Scanning electron microscopy showed that the coarser profile in the corroded region of the cobalt chrome head was similar to the profile on the titanium stem taper. Pitting corrosion was evident in the grooves on the cobalt chrome. The smooth mini-spigots were less affected. Conclusions: In cobalt chrome- titanium alloy combinations where the surface finish on the taper is coarse, corrosion is increased on a mini spigot compared with standard spigot. Surface finish is crucial and corrosion of the mini spigot is reduced if the surface finish is smooth

Introduction: Despite improved cementing techniques, the long term survival of hip arthroplasty in younger patients have been disappointing. THA in this group of young and active patients remains a major challenge. Consequently, cementless components have been developed. Longer implant survival, preservation of bone stock and ‘easier’ revisions have been advocated as potential benefits of cementless stems. Up to date there are only few reports in the literature on the long term results of uncemented stems. Like in cemented THA, 10 year survival of at least 90% is required for any THA. Materials and Methods: We followed 133 implantations of an uncemented, grit blasted straight titanium stem (CLS, Zimmer Inc, Warsaw, USA). The mean follow-up evaluation was 14 (10 – 20) years. The mean age at surgery was 37 (16 – 45) years. Results: At follow-up, 14 patients (10,5%) had died, and 10 (7,5%) were lost to follow-up. 3 patients under-went femoral revision. One for infection an two for aseptic loosening of the stem. There was no case of clinical or radiographic loosening at the time of follow-up. Overall survival was 96% at 14 years, survival with femoral revision for aseptic loosening as an end point was 97% at 14 years. The mean Harris-Hip-Score at follow-up was 81 points (range 45–100). 96 hips were available for radiolographic evaluation. Radiolucent lines (< 2mm) in Gruen zone 1 were present in 7 hips and in Gruen zone 7 in 2 hips, respectively. Small osteolytic lesions (< 1cm) in Gruen zone 1 were present in one hip and in Gruen zone 7 in 5 hips. Larger lesions (> 1cm) were present in one case in Gruen zone 1 and 7. No osteolysis or radiolucency was found in zones 2 – 6. No case of severe femoral osteolysis was found. Conclusions: The long-term results with this type uncemented stem in a young and active patient group are encouraging and better than those of cemented stems in this age group. We recommend the uncemented CLS stem for hip arthroplasty in young demanding patients

Aim: To examine the effect that a modular, uncemented, fully coated titanium stem (PFM-R, Protek) has on the bone stock of revised femora. Methods: Forty revision hip arthroplasties between 1997–2000 were performed by one surgeon using the PFM-R revision stem. The patients were assessed radiographically over a two-year follow-up period. The pre-operative radiographs were examined for bone defects according to Paprosky et al., 1987. Serial radiographs taken post-operatively after two days, six weeks, three months, six months, 12 months and 24 months were used to assess signs of fixation, stability and change in the cortices of 16 femoral zones according to criteria set out by Engh et al., 1987. The change in the density of the bone defects identified at the time of surgery was also examined. Results: The average age of the patients was 65 years. Thirteen revision stems were followed for one year and 13 were followed for two years. Fourteen patients had an incomplete radiographic follow-up. Two type I defects, 23 type II defects and one type III defect were identified. Twenty-one of the 23 type II defects showed evidence of regeneration in the subtrochanteric metaphysis. One revision stem had radiographic evidence of bone resorption proximally though three stems subsided. No stress shielding was seen distally. Conclusion: At early follow-up the PFM-R appears to be a viable revision femoral implant which facilitates the regeneration of metaphyseal bone stock

The fixation concept of a fluted, conical, tapered grit-blasted titanium stem has been employed successfully in Europe, but the experience in North America with implants of this design is more limited. The most commonly studied stem of this design, the Wagner stem has been reported to provide good pain relief function and implant stability in several aeries, although large series with long-term follow-up are lacking. Implants with a similar distal geometry but modular proximal features were introduced in an attempt to solve one of the practical difficulties of using a stem of this design: determining where the implant would seat was difficult, trialing options were limited, and accurate leg length and soft tissue balancing were difficult. Modular implants are more user-friendly but have the theoretical disadvantage of introducing the potential for modular junction failure (failure due to fatigue or fretting). To date, there are only limited (but favourable) short-term reported results on the efficacy of this form of revision. Implants of this design can be used when rotational stability, axial stability, and long-term implant fixation must be gained primarily from the distal diaphysis of the femur. Examples include patients with periprosthetic femur fractures and patients with marked proximal bone thinning but good diaphyseal bone. From the practical viewpoint, the fluted section of these implants must be straight (to allow milling of a cone-shaped diaphysis) and thus anterior cortical perforation is a potential complication. Anterior extended osteotomy as described by Wagner accomplishes the goal of femoral exposure and helps prevent distal anterior femoral perforation

Aims. Modular dual mobility (DM) prostheses in which a cobalt-chromium liner is inserted into a titanium acetabular shell (vs a monoblock acetabular component) have the advantage of allowing supplementary screw fixation, but the potential for corrosion between the liner and acetabulum has raised concerns. While DM prostheses have shown improved stability in patients deemed ‘high-risk’ for dislocation undergoing total hip arthroplasty (THA), their performance in young, active patients has not been reported. This study’s purpose was to assess clinical outcomes, metal ion levels, and periprosthetic femoral bone mineral density (BMD) in young, active patients receiving a modular DM acetabulum and recently introduced titanium, proximally coated, tapered femoral stem design. Patients and Methods. This was a prospective study of patients between 18 and 65 years of age, with a body mass index (BMI) < 35 kg/m. 2. and University of California at Los Angeles (UCLA) activity score > 6, who received a modular cobalt-chromium acetabular liner, highly crosslinked polyethylene mobile bearing, and cementless titanium femoral stem for their primary THA. Patients with a history of renal disease and metal hardware elsewhere in the body were excluded. A total of 43 patients (30 male, 13 female; mean age 52.6 years (. sd. 6.5)) were enrolled. All patients had a minimum of two years’ clinical follow-up. Patient-reported outcome measures, whole blood metal ion levels (ug/l), and periprosthetic femoral BMD were measured at baseline, as well as at one and two years postoperatively. Power analysis indicated 40 patients necessary to demonstrate a five-fold increase in cobalt levels from baseline (alpha = 0.05, beta = 0.80). A mixed model with repeated measures was used for statistical analysis. Results. Mean Harris Hip Scores improved from 54.1 (. sd. 20.5) to 91.2 (. sd. 10.8) at two years postoperatively (p < 0.001). All patients had radiologically well-fixed components, no patients experienced any instability, and no patients required any further intervention. Mean cobalt levels increased from 0.065 ug/l (. sd. 0.03) preoperatively to 0.30 ug/l (. sd. 0.51) at one year postoperatively (p = 0.01) but decreased at two years postoperatively to 0.16 ug/l (. sd. 0.23; p = 0.2). Four patients (9.3%) had a cobalt level outside the reference range (0.03 ug/l to 0.29 ug/l) at two years postoperatively, with values from 0.32 ug/l to 0.94 ug/l. The mean femoral BMD ratio was maintained in Gruen zones 2 to 7 at both one and two years postoperatively using this stem design. At two years postoperatively, mean BMD in the medial calcar was 101.5% of the baseline value. Conclusion. Use of a modular DM prosthesis and cementless, tapered femoral stem has shown encouraging results in young, active patients undergoing primary THA. Elevation in mean cobalt levels and the presence of four patients outside the reference range at two years postoperatively demonstrates the necessity of continued surveillance in this cohort. Cite this article: Bone Joint J 2019;101-B:365–371

Summary Statement. In young, active patients cementless THR demonstrates excellent prosthetic stability by RSA and outstanding clinical outcomes at 5 years using a tapered titanium femoral stem, crosslinked polyethylene liners and either titanium or tantalum shells. Introduction. Early femoral implant stability is essential to long-term success in total hip replacement. Radiostereometric analysis (RSA) provides precise measurements of micromotion of the stem relative to the femur that are otherwise not detectable by routine radiographs. This study characterised micromotion of a tapered, cementless femoral stem and tantalum porous-coated vs. titanium acetabular shells in combination with highly cross-linked UHMWPE or conventional polyethylene liners using radiostereometric analysis (RSA) for 5 years following THR. Patients and Methods. This IRB-approved, prospective, double randomised, blinded study, involved 46 patients receiving a primary THR by a single surgeon. Each patient was randomised to receive a titanium (23) (Trilogy, Zimmer) or tantalum (23) (Modular Tantalum shell, Zimmer) uncemented hemispheric shell and either a highly-crosslinked or conventional polyethylene liner. Tantalum RSA markers were implanted in each patient. All patients had a Dorr A or B femoral canal and received a cementless, porous-coated titanium tapered stem (M/L Taper, Zimmer). All final femoral broaches were stable to rotational and longitudinal stress. RSA examinations, Harris Hip, UCLA, WOMAC, SF-12 scores were obtained at 10 days, 6 months, and annually through 5 years. Results. All patients demonstrated statistically significant improvement in Harris Hip, WOMAC, and SF-12 PCS scores post-operatively. Evaluation of polyethylene wear demonstrated that median penetration measurements were significantly greater in the conventional compared to the HXPLE liner cohorts at 1 year through 5 years follow-up (p<0.003). At 5 years, conventional liners showed 0.38 ± 0.05mm vertical wear whereas HXLPE liners showed 0.08 ± 0.02mm (p<0.003). Evaluation of the femoral stems demonstrated that the rate of subsidence was highest in the first 6 months (0.09mm/yr), with no other detectable motion through 5 years. Two outlying patients had significantly higher stem subsidence values at 6 months (0.7 mm and 1.0mm). One stem stabilised without further subsidence after 6 months (0.7mm), and the other stem stabilised at 1 year (1.5mm). Neither patient has clinical evidence of loosening. Evaluation of acetabular shells demonstrated less median vertical translation in tantalum than titanium shells at each time-point except at 3-years follow-up, however due to large standard errors, there was no significant difference between the two designs (p>0.05). These large standard errors were predominantly caused by two outliers, neither of which had clinical evidence of loosening. Discussion/Conclusion. In this RSA study of young THR patients, cementless tapered femoral stems, highly crosslinked polyethylene liners, and tantalum or titanium acetabular shells all demonstrated excellent performance through 5 years follow-up. Highly crosslinked polyethylene liners demonstrated significantly less wear than conventional liners. The femoral stem showed excellent stability through 5 years, with no clinical or radiologic episodes of failure. The small amount of micromotion seen is less than that previously reported for similar tapered, cementless stems and approaches the accuracy of RSA (0.05mm). Both acetabular shells demonstrated excellent stability with minimal micromotion at 5 years without significant differences in migration. All patients demonstrated significant clinical improvement in pain and function and additional RSA evaluation of these patients is planned

The study was designed to compare the clinical performance of an Alumina ceramic acetabular bearing to that of a polyethylene bearing in a cementless hip couple. The study group consisted of 15 surgeons who performed 308 total hip replacements (297 patients) between January 29, 1998 and February 1, 2000. All patients received a porous coated cementless titanium stem with an Alumina ceramic 28 mm or 32 mm head. Patients were randomized to receive a porous titanium acetabular shell with either a polyethylene or Alumina cup liner. There were 164 Alumina cups and 144 polyethylene cups. The mean age was 57.3 years and consisted of 50% males and 50% females. The preoperative diagnoses were: osteoarthritis 69.8%, avascular necrosis 19.5 %, post traumatic arthritis 2.9 %, inflammatory arthritis 3.9% and other 3.9%. The mean follow up was 12 months. The longest follow up was 38 months. The Harris Hip Score was good and excellent in 86% of the control patients and 87% of the study patients. There has been 100% follow up and survivorship. There were two reoperations for recurrent dislocations in each group. There were no Alumina component fractures, no progressive radiolucencies and no evidence of rapid wear. In the short term follow-up between 12 and 38 months, there do not appear to be any differences between the patients with a bearing couple consisting of Alumina on plastic with those consisting of Alumina on Alumina. There have been no catastrophic failures of the ceramic components. The Alumina/Alumina bearing couple for total hip arthroplasty appears to be an excellent alternative bearing, providing the advantage of improved long term wear and a reduced incidence of polyethylene induced osteolysis

Cementless femoral fixation is the gold standard in revision hip arthroplasty. Distal fixation is achieved using either a cobalt chrome or titanium stem. The purpose of this study is to report the long-term survivorship and clinical outcome of a titanium, long-stemmed, load-bearing calcar-replacement femoral component from an independent centre. Eighty-one patients (average seventy-four years, range thirty-five to ninety-one) underwent hip arthroplasty with the Mallory-Head calcar-replacement femoral component, by a single surgeon. There were thirty-eight males and forty-three females with fifty-four hips initially revised for aseptic loosening, thirteen for peri-prosthetic fracture, and five for infection as a two-stage procedure. The implant was used as a primary device in eight patients with deformed proximal femurs. At most-recent follow-up, radiographic analysis was conducted and clinical outcome scoring was assessed using the SF-12, Harris Hip Score, and WOMAC questionnaire for surviving patients. Complications were also reviewed. At a mean follow-up of 7.4 years (range four to fifteen), eight patients have died. There was one deep infection, three DVT’s, and two dislocations in the perioperative period. Six femoral stems have ultimately required another revision surgery for aseptic loosening, two for infection, and 1 for implant fracture at a mean of 5.6 years after initial revision. Four patients required removal of the proximal trochanteric bolt due to breakage or loosening. Overall survival of the implant at five years is 95% (CI 0.87–0.98) and 87% (CI 0.72–0.94) at ten years. The clinical outcome of the Mallory-Head calcar-replacement femoral revision stem is reported from an independent centre. Although the results are encouraging, it would appear that proximal load-bearing fixation with the calcar-replacement stem is not as reliable as distal fixation. The use of a trochanteric bolt was associated with fracture of the greater trochanter or need for a separate surgical procedure for removal. For this series, there was an overall 11% failure rate at a mean follow-up of 7.4 years. The mechanical failure rate is 7.4%. Our overall and mechanical failure rates are somewhat higher than those of the implant developers, who reported 94% overall survival, and a 1.9% mechanical failure rate at a mean follow-up of eleven years

Introduction: There has been a proliferation of newer fluted tapered grit-blasted titanium stems in hip revision arthroplasty. However, only a limited number of clinical series have so far been reported in the literature. Moreover, all reports have only a short-term clinical and radiographical follow-up (< 5 years). Medium-term and long-term follow-up studies are lacking. Therefore, the aim of this study was to review a series of a cementless modular tapered revision femoral component (MP Link hip reconstruction prosthesis) with a minimum 5 year follow-up. Patients and Methods: This study includes 90 consecutive cases (87 patients) with the MP stem. We documented the Harris hip score (HHS) and the Visual analogue scale (VAS) was used to assess pain at rest and movement. Survivorship was calculated using Kaplan-Meier survival analysis. The 95% confidence intervals (CI) for the cumulative 5 year survival were calculated. Radiographs made immediately after the index operation were compared with those at follow-up examination in order to classify the restoration of femoral bone and vertical migration of the implant. Results: Of the original 90 cases, 24 (27%) died prior to clinical and radiographical review, 2 (2%) had a stem revision and 1 (1%) was lost to follow-up. Patients who died and were lost to follow-up were included in the survival analysis. For those patients, all data concerning complications and revisions were extracted from journal files and the Swedish Hip Register which collects all information on reoperations after hip revision surgery. The median follow-up time was 6 (5–11) years. The median VAS for pain for the affected hip was 0 (0–5) at rest and 0 (0–9) at movement. The median HHS at follow-up was 78 (16–100) points. 17 (19%) patients dislocated their hips during follow-up. A prosthesis head size of 22 mm was present in 6/17 (35%) patients with dislocation and in 11/73 (15%) patients without dislocation (P = 0.055). The cumulative 5 year survival rate was 98% (95% CI: 94–100%) with stem removal and 90% (95% CI: 85–96%) with any reoperation as the endpoint. At follow-up, we noted subjectively that 17% of the cases had evidence of proximal bone restoration, whereas 44% had constant defects. In 39% the quality of the proximal bone appeared to be declining. If present, this was mostly seen around the lesser trochanter. The median vertical stem migration was 2.7 (0–30) mm. Discussion: This is the first report with a clinical and radiographical medium-term follow-up of patients with a cementless modular tapered distally fixated hip revision stem. In our study, we found a discrepancy between a high implant survivorship and good pain relief on one hand and a high dislocation rate on the other hand

We describe the development and early clinical application of a ported, proximally-cemented titanium stem for cemented total hip arthroplasty. PMMA bone cement is delivered to the proximal femur under pressure after the stem has been positioned within the femoral canal. A mid-stem cement occluder contains the cement to the proximal stem only. A tapered body is incorporated in the design of the stem to reduce the structural stiffness and hence the degree of stress shielding within the reconstructed joint. We performed preclinical studies to measure the reduction in porosity and the pressurisation achieved. The porosity, as measured by the void percentage within the cured cement mantle, was reduced by more than 50% and there was an almost threefold increase in the mean pressure. Mechanical testing of the stem, using a three-point bend test, showed that the addition of cement injection ports on the anterior and posterior sides of the body of the proximal stem did not reduce its strength. Finite-element analysis indicated that, compared with a fully-cemented conventional stem, there was no change in the stresses within the cement mantle. In a series of 40 proximally-cemented stems followed for up to six years (mean 51 months) the mean Harris hip score was 91, and 85% of patients had good or excellent results. There was excellent pain relief, an increased level of activity and good patient satisfaction. One mechanical failure of the stem required revision at three years after implantation. The early results indicate that the clinical performance was equal to that achieved with other modern cemented stems. Radiological evaluation showed excellent results with no evidence of stress shielding. Further follow-up will determine if long-term stress shielding is reduced and if revision is made easier by the absence of a distal cement mantle

Aims

We present the clinical and radiological results at a minimum follow-up of 20 years using a second-generation uncemented total hip arthroplasty (THA). These results are compared to our previously published results using a first-generation hip arthroplasty followed for 20 years.

We describe the clinical and radiological results of 120 consecutive revision hip replacements in 107 patients, using a titanium alloy femoral component fully coated with Hydroxyapatite ceramic (HAC). The mean age at operation was 71 years (range 36 to 92). The average length of follow up was 8.0 years (range 5.0 to 12.4). All patients receiving a JRI Furlong HAC coated femoral component (JRI Instrumentation Ltd, London, UK) with a minimum follow up of 5 years were included. These included patients on whom previous revision hip joint surgery had taken place. Patients were independently reviewed and scored using the Harris Hip Score (HHS), the Charnley modification of the Merle d’Aubigne and Postel Score (MDP), and The Western Ontario and McMaster Universities Osteoarthritis index (WOMAC). Radiographs were assessed by three reviewers (blinded to clinical details) for new bone formation, osteolysis, osteointegration and radiolucent lines in each Gruen Zone. The mean Harris hip score was 85.8 (range 42 to 100) at the latest post-operative review. The mean WOMAC and MDP scores were 34.5 and 14.8 respectively. The mean pain visual analogue score (range 0 to 10) was 1.2 overall and 0.5 specifically for mid-thigh pain. There were no revisions of any femoral component for aseptic loosening. There were four stem re-revisions (3 cases of infection, 1 recurrent dislocation). Radiological review of all femoral components, including the four mentioned, revealed stable bone ingrowth with no new radiolucent lines in any zone. Using revision or impending revision for aseptic loosening as the end point, at 10 years the cumulative survival for the stem was 100% (95% CI 94 to 100). We present excellent medium to long term clinical, radiological and survivorship results with the use of a fully HAC coated titanium stem in revision hip surgery

Aims

Highly cross-linked polyethylene (HXLPE) has greatly improved the durability of total hip arthroplasty (THA) in young patients because of its improved wear characteristics. Few studies have followed this population into the second decade, and therefore the purpose of this investigation was to evaluate the clinical outcome for THA patients 50 years of age and younger at a minimum of 15 years postoperatively. The second purpose was to evaluate the radiological findings secondary to wear or mechanical failure of the implant.