Aims

The aim of this study was to evaluate the survival of a collarless, straight, hydroxyapatite-coated femoral stem in total hip arthroplasty (THA) at a minimum follow-up of 20 years.

Aims

Although the Fitmore Hip Stem has been on the market for almost 15 years, it is still not well documented in randomized controlled trials. This study compares the Fitmore stem with the CementLeSs (CLS) in several different clinical and radiological aspects. The hypothesis is that there will be no difference in outcome between stems.

Aims

The aim of this study was to determine whether total hip arthroplasty (THA) for chronic hip pain due to unilateral primary osteoarthritis (OA) has a beneficial effect on cognitive performance.

Aims

Preoperative nasal Staphylococcus aureus screening and eradication reduces surgical site infections (SSIs) but its impact on reducing early prosthetic joint infection (PJI) remains controversial. This study aims to assess the effect of preoperative nasal S. aureus screening and eradication on the incidence of early PJI in general and S. aureus-induced early PJI.

Aims

This study reports the mid-term results of total hip arthroplasty (THA) performed using a monoblock acetabular component with a large-diameter head (LDH) ceramic-on-ceramic (CoC) bearing.

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.

Background. The clinical results of total hip arthroplasty (THA) with a cementless prosthesis have been constantly improving due to progress in the area of stem design and surface finish. However, majority of stems are well-fixed with canal filling or diaphyseal fit, and cortical hypertrophy or metaphyseal bone atrophy has been often observed. Cementless Spotorno stem (CLS stem; Zimmer, Warsaw, USA) is a double-tapered rectangular straight stem. The purpose of this study is to investigate the mean 13 years' results of CLS stem and to evaluate the press-fit stability of CLS stem. Methods. Between 1999 and 2004, we treated 134 patients (142 hips) with CLS stem. Of those patients, 86 females (92 hips) and 13 males (14 hips), in total 99 patients (106 hips) were available at minimum of 11 years after surgery. At the time of follow-up, six females and five males were dead. The follow-up rate was 82% and the mean follow-up period was 13 years (SD; 20, range; 11–16). The mean age at the time of surgery was 65 years (SD; 10, range; 38–86). The mean body mass index was 24 (SD; 1.8, range; 19 to 28). Preoperative diagnoses were osteoarthritis in 92 patients, osteonecrosis in five patients, and rheumatoid arthritis in two patients. Majority of the patients were female because 84 patients of osteoarthritis suffered from hip dysplasia. For cementless acetabular reconstruction, APR cups (Zimmer, Warsaw, USA) were implanted in 10 hips, IOP cups (Zimmer, Warsaw, USA) in 22 hips, and Converge cups (Zimmer, Warsaw, USA) in 74 hips. As the liner of acetabular component, conventional UHMWPE (Sulene: Zimmer, Warsaw, USA) was used in APR cup and highly crosslinked UHMWPE (Durasul: Zimmer, Warsaw, USA) in IOP and Converge cups. The lipped liner was chosen in all cases, and lipped lesion was placed posteriorly. The radiographic stability of the femoral stem was determined by Engh's criteria. The ascertained period of spot welds was noted by Gruen zones on the femoral side. The presence of stress shielding, and subsidence was also evaluated. Results. A stable stem with bony on-growth was identified in all cases. The mean period of expression of spot welds was 11 months in zone 2, 10 months in zone 3, 9 months in zone 5, and 9 months in zone 6. Stress shielding of more than grade 2 was observed in only 8 hips, which was non-progressive at 1 year after surgery. Subsidence of more than 2mm was not observed in any of the hips. The cortical hypertrophy at the tip of stem was not observed. The postoperative dislocation occurred in six hips (6%) and periprosthetic femoral fracture occurred in two hips (2%). Revised surgery was performed in three hips for a recurrent dislocation and two periprosthetic femoral fracture. Conclusions. Excellent stability of CLS stem has been maintained without abnormal bone reaction at proximal femur. CLS stem is considered to achieve not only press-fit stability at trochanteric and subtrochanteric level, but bony fixation by osseointegration within 1 year after THA

Aims

Periprosthetic femoral fractures (PFF) following total hip arthroplasty (THA) are devastating complications that are associated with functional limitations and increased overall mortality. Although cementless implants have been associated with an increased risk of PFF, the precise contribution of implant geometry and design on the risk of both intra-operative and post-operative PFF remains poorly investigated. A systematic review was performed to aggregate all of the PFF literature with specific attention to the femoral implant used.

Aims

We present a minimum 20-year follow-up study of 382 cemented Exeter Universal total hip arthroplasties (350 patients) operated on at a mean age of 66.3 years (17 to 94).

Modern prosthetic stem construction strives to achieve the attractive goals of stress shielding prevention and optimal osteointegration. PhysioLogic stem is a new generation composite isoelastic femoral stem consisting of titanium core sheathed in implantable PEEK polymer and coated with titanium layer. This construction combines the benefits of both stress shielding prevention, due to its elasticity under bending load corresponding closely to that of natural bone, and rapid osteointegration, due to the stem's titanium coating. The aim of this study is long-term clinical progress evaluation and retrospective analysis in patients undergoing primary PhysioLogic stem implantation at our institution. From 1998 to 2003, we performed 51 primary total hip arthroplasty (THA) operations with implantation of PhysioLogic Stem at our institution. Indications for THA included osteoarthritis (21), hip dysplasia (14), rheumatoid arthritis (10), and femoral neck nonunion (6). In all patients we used totally uncemented system — PhysioLogic Stem and monoblock cup with different types of bearing surface articulation (40 metal/polyethylene, 3 ceramic/polyethylene, and 8 metal/metal). In all cases head size was 28mm. Two patients died in the early post-op period at day 1 and day 9 from disseminated intravascular coagulation and pulmonary embolism, respectively, and were excluded from subsequent analysis. Analyzed patients included 20 women and 29 men; median age 45, range 21–69. Post-operatively, the patients were evaluated at 3 and 6 months, 1 year, and yearly thereafter. Median follow-up period was 14 years, range 11 to 16 years. Clinical and functional outcomes were evaluated by Harris Hip Score. Bone density in Gruen's and Charnley's zones was measured by dual-energy x-ray absorptiometry. Four patients died at 5–8 years postoperatively from cardiac causes. Two patients underwent revision surgery: one patient underwent “dry revision” due to hip dislocation with exchange for longer head while keeping the original PhysioLogic stem in place; second patient underwent stem removal after chronic periprosthetic infection. Among the 45 patients with surviving PhysioLogic Stem, 33 patients (75%) underwent subsequent contralateral total hip arthroplasty with standard uncemented stems types Spotorno or Zweymuller. These patients were surveyed at postoperative evaluation about subjective comparative performance of PhysioLogic Stem versus standard stem. Twenty seven patients (82%) reported the PhysioLogic stem to be equivalent or superior to the standard stem, with 15 patients (45%) rating the PhysioLogic stem as subjectively more comfortable than the standard stem. The average Harris hip score improved from 40 points preoperatively (range 27 to 48) to 93 points (range 89 to 95) at the time of final follow-up. All stems continue to show adequate bone-ingrown fixation with no radiological signs of aseptic loosening to date. The PhysioLogic stem removed in the aforementioned case of chronic periprosthetic infection also showed clear signs of good osteointegration. Our study showed that the PhysioLogic stem implantation resulted in favorable clinical and functional performance at long-term follow-up, making it an attractive alternative to standard stems

The aim of this study was to assess the effect of frictional torque and bending moment on fretting corrosion at the taper interface of a modular femoral component and to investigate whether different combinations of material also had an effect. The combinations we examined were 1) cobalt–chromium (CoCr) heads on CoCr stems 2) CoCr heads on titanium alloy (Ti) stems and 3) ceramic heads on CoCr stems.

In test 1 increasing torque was imposed by offsetting the stem in the anteroposterior plane in increments of 0 mm, 4 mm, 6 mm and 8 mm when the torque generated was equivalent to 0 Nm, 9 Nm, 14 Nm and 18 Nm.

In test 2 we investigated the effect of increasing the bending moment by offsetting the application of axial load from the midline in the mediolateral plane. Increments of offset equivalent to head + 0 mm, head + 7 mm and head + 14 mm were used.

Significantly higher currents and amplitudes were seen with increasing torque for all combinations of material. However, Ti stems showed the highest corrosion currents. Increased bending moments associated with using larger offset heads produced more corrosion: Ti stems generally performed worse than CoCr stems. Using ceramic heads did not prevent corrosion, but reduced it significantly in all loading configurations.

Cite this article: Bone Joint J 2015;97-B:463–72.

The long-term survival of the cementless Spotorno CLS femoral component in patients aged > 50 years at the time of arthroplasty was investigated. Survivorship analysis of a consecutive series of 85 patients (100 hips; under 50 years of age at a mean follow-up of 18.4 years (16.3 to 20.8)) was performed. The clinical and radiographic outcomes were satisfactory. The overall rate of survival of the femoral component was 93.5% (95% confidence interval (CI), 90.9 to 96.1) after 19 years. Survival with revision for aseptic loosening as the end point was 95.7% (95% CI 93.6 to 97.8%) at 19 years.

This study demonstrates an excellent long-term survival of the Spotorno CLS femoral component after 16 to 20 years in young patients undergoing total hip arthroplasty.

Cite this article: Bone Joint J 2015;97-B:160–3.

Large-head metal-on-metal (MoM) total hip replacements (THR) have given rise to concern. Comparative studies of small-head MoM THRs over a longer follow-up period are lacking. Our objective was to compare the incidence of complications such as infection, dislocation, revision, adverse local tissue reactions, mortality and radiological and clinical outcomes in small-head (28 mm) MoM and ceramic-on-polyethylene (CoP) THRs up to 12 years post-operatively.

A prospective cohort study included 3341 THRs in 2714 patients. The mean age was 69.1 years (range 24 to 98) and 1848 (55.3%) were performed in women, with a mean follow-up of 115 months (18 to 201). There were 883 MoM and 2458 CoP bearings. Crude incidence rates (cases/1000 person-years) were: infection 1.3 vs 0.8; dislocation 3.3 vs 3.1 and all-cause revision 4.3 vs 2.2, respectively. There was a significantly higher revision rate after ten years (adjusted hazard ratio 9.4; 95% CI 2.6 to 33.6) in the MoM group, and ten of 26 patients presented with an adverse local tissue reaction at revision. No differences in mortality, osteolysis or clinical outcome were seen.

In conclusion, we found similar results for small-head MoM and CoP bearings up to ten years post-operatively, but after ten years MoM THRs had a higher risk of all-cause revision. Furthermore, the presence of an adverse response to metal debris seen in the small-head MOM group at revision is a cause for concern.

Cite this article: Bone Joint J 2014; 96-B:868–75.

In 2012 we reviewed a consecutive series of 92 uncemented THRs performed between 1986 and 1991 at our institution using the CLS Spotorno stem, in order to assess clinical outcome and radiographic data at a minimum of 21 years. The series comprised 92 patients with a mean age at surgery of 59.6 years (39 to 77) (M:F 43;49). At the time of this review, seven (7.6%) patients had died and two (2.2%) were lost to follow-up. The 23-year Kaplan–Meier survival rates were 91.5% (95% confidence intervals (CI) 85.4% to 97.6%; 55 hips at risk) and 80.3% (95% CI, 71.8% to 88.7%; 48 hips at risk) respectively, with revision of the femoral stem or of any component as endpoints. At the time of this review, 76 patients without stem revision were assessed clinically and radiologically (mean follow-up 24.0 years (21.5 to 26.5)). For the 76 unrevised hips the mean Harris hip score was 87.1 (65 to 97). Femoral osteolysis was detected in five hips (6.6%) only in Gruen zone 7. Undersized stems were at higher risk of revision owing to aseptic loosening (p = 0.0003). Patients implanted with the stem in a varus position were at higher risk of femoral cortical hypertrophy and thigh pain (p = 0.0006 and p = 0.0007, respectively). In our study, survival, clinical outcome and radiographic data remained excellent in the third decade after implantation. Nonetheless, undersized stems were at higher risk of revision owing to aseptic loosening. Cite this article: Bone Joint J 2014;96-B:455–61

Many different lengths of stem are available for use in primary total hip replacement, and the morphology of the proximal femur varies greatly. The more recently developed shortened stems provide a distribution of stress which closely mimics that of the native femur. Shortening the femoral component potentially comes at the cost of decreased initial stability. Clinical studies on the performance of shortened cemented and cementless stems are promising, although long-term follow-up studies are lacking. We provide an overview of the current literature on the anatomical features of the proximal femur and the biomechanical aspects and clinical outcomes associated with the length of the femoral component in primary hip replacement, and suggest a classification system for the length of femoral stems.

Cite this article: Bone Joint J 2014;96-B:442-8.

Introduction. Many finite element (FE) studies have been performed in the past to assess the biomechanical performance of TKA and THA components. The boundary conditions have often been simplified to a few peak loads. With the availability of personalized musculoskeletal (MS) models we becomes possible to estimate dynamic muscle and prosthetic forces in a patient specific manner. By combining this knowledge with FE models, truly patient specific failure analyses can be performed. In this study we applied this combined technique to the femoral part of a cementless THR and calculated the cyclic micro-motions of the stem relative to the bone in order to assess the potential for bone ingrowth. Methods. An FE model of a complete femur with a CLS Spotorno stem inserted was generated. An ideal fit between the implant and the bone was modeled proximally, whereas distally an interface gap of 100μm was created to simulate a more realistic interface condition obtained during surgery. Furthermore, a gait analysis was performed on a young subject and fed into the Anybody™ MS modeling system. The anatomical data set (muscle attachment points) used by the Anybody™ system was morphed to the shape of the femoral reconstruction. In this way a set of muscle attachment points was obtained which was consistent with the FE model. The predicted muscle and hip contact forces by the Anybody™ modeling system were dynamic and divided into 37 increments including two stance phases and a swing phase of the right leg. Results. The magnitude and path of interface micromotions was heavily dependent on the location on the implant. In the proximal region, a unidirectional pattern was visible in proximal-distal direction (max. motion was 39μm). Mid stem micromotions were very small (in the order of 4μm), whereas in the distal region, micromotions had a tendency to develop in anterior-posterior and medial-lateral direction (max. motion was 96μm). Hence, in this example, ingrowth is most likely to start in the mid-region. Conclusion. By combining finite element models with musculoskeletal models more realistic, dynamical simulations can be generated to assess the biomechanical behavior of prosthetic components. Both, FE models as well as MS models can be personalized, which offers the possibility to perform truly patient specific predictions. Furthermore, by performing personalized MS and FE calculations, a database is established containing variability of kinematic, force and reconstructive parameters in patients. With this database new implants can be tested in a more robust and reliable manner than before, thereby reducing the chance that innovative ‘defective’ implants are launched on the market

CLS Spotorno expansion acetabular cup is in use since 1984 for uncemented Metal-Polyethylene (PE) total hip arthroplasties (THA). Metal-PE articulations are notoriously known to wear and lead to failure of THA. However, catastrophic breakage of expansion acetabular cup is rare. Our 74-year-old male who was diagnosed with bilateral osteonecrosis of femoral head, underwent bilateral THA using CLS Spotorno metal expansion acetabular cups (Protek, AG, Bern) in 1991. He had irregular follow-up since then. In 2005, he presented with right hip pain and inability to walk without support. Anteroposterior (AP) hip radiographs established the diagnosis of catastrophic failure of right THA secondary to severe liner wear and acetabular osteolysis. Patient chose to postpone the revision surgery and opted for wheel chair ambulation. He presented 4 years later, when the right hip pain became unbearable. Anteroposterior as well as lateral hip radiographs showed worsening of cup breakage with superolateral migration of metal femoral head. Pelvic CT scans confirmed severe acetabular osteolysis in DeLee and Charnley's Zone 1, 2 & 3 with secondary loss of bony support to the expansion cup [Fig. 1]. A revision THA was strongly advised. However, patient sought for a pain-free rather than a fully ambulatory right hip and decided against a second THA. We performed resection arthroplasty of right hip with bone cement loading, respecting patient's decision. Intra-operatively, the metal femoral head was lying in the huge osteolytic defect in the roof of acetabulum. The 3 cranial wings of metal expansion shell were broken with corresponding wear of the cranial pole of polyethylene liner [Fig. 2]. We were able to gratify patient's expectations and patient is able to ambulate with the aid of one crutch at latest follow-up. However, it is clearly evident that a timely and regular follow-up would have identified the initial PE wear and secondary osteolysis. Additionally, it can avoid extensive procedures like a revision THA or resection arthroplasty by allowing simple procedures like modular PE liner and the femoral head exchange. A comprehensive review of literature for catastrophic acetabular component breakage revealed 10 such cases, although with different cup designs. To the best of our knowledge, this is the first case of CLS expansion cup breakage for metal-PE articulation. Majority of these cases have a presence of extensive liner wear and pelvic osteolysis along with a post-operative irregular follow up. This case stresses on importance of regular follow-up even after many years of index THA to identify early PE wear and prevent secondary catastrophic complications

The need to demonstrate probity and fair market competition has increased scrutiny of the relationships between orthopaedic surgeons and the industry that supplies them with their tools and devices. Investigations and judgements from the US Department of Justice and the introduction of the AdvaMed and Eucomed codes have defined new boundaries for interactions between these groups. This article summarises the current interplay between orthopaedic surgeons and industry, and provides recommendations for the future.

Introduction: High survival rates have been reported for the uncemented CLS Spotorno stem up to 20 years. To confirm survival at longer follow-up we report the minimum 20-year (mean, 22 years; range, 20–25 years) results using this device. Methods: We retrospectively evaluated the clinical and radiographic results of a consecutive series of 354 total hip arthroplasties using an uncemented grit-blasted, tapered femoral stem (CLS Spotorno) in 326 patients. Mean time of follow-up evaluation was 22 years (range, 20–25 years), mean age at surgery was 57 years (range, 13–81 years). Clinical results were evaluated using the Harris Hip Score. Kaplan-Meier survivorship analysis was used to determine long term outcomes for different end points. Results: At final follow-up, 126 patients (136 hips) had died, and 7 patients (8 hips) were lost to follow-up. Forty-one hips (12%) in 38 patients underwent femoral revision – 10 (3%) for infection, 12 (3%) for late periprosthetic fracture, and 19 (5%) for aseptic loosening of the stem. Kaplan-Meier analysis, with revision of the femoral component for any reason as the end point, revealed that the survival rate at 22 years was 86% (95%-confidence limits, 82%–90%). The survival rate with femoral revision for aseptic loosening as the end point was 93% at 22 years (95%-confidence limits, 90% – 96%). Discussion and Conclusion: The long-term results with this type of uncemented femoral component are encouraging and compare to the best reported series in primary cemented total hip arthroplasty. Besides aseptic loosening, periprosthetic femoral fracture is an important mode of failure in the long term following uncemented THA

Introduction: Continous periprosthetic bone loss after uncemented THA may lead to proximal femoral atrophy and increase the risk for aseptic loosening or peripros-thetic femoral fracture in the long-term. Little is known about the extent and the pattern of bone remodeling around stable, straight uncemented stems after 15 years. Patients and Methods: In a prospective longitudinal study, bone mineral density (BMD) was measured in 131 patients with 146 stable, uncemented, double- tapered, grit- blasted stems (CLS Spotorno, Zimmer, Warsaw, USA) using dual- energy x-ray absorptiometry (DEXA) after a mean of 12 years (range:10–15, t1) postoperatively. Patients were followed with radiographs and Harris hip scores (HHS), and a second and third DEXA were performed at a mean follow-up of 17 years (range: 15–20, t2) and 22 years (range: 20–25, t3) using the identical protocol. Results: We obtained a complete prospective set of data of three consecutive DEXA measurements for 37 hips (32 patients, 14 male, 18 female). In all cases regular bone ongrowth did occur and on radiographic evaluation there were no signs of loosening and no significant change in periprosthetic bone formation. There was no case of severe bone loss and no case of diaphyseal cortical hypertrophy. We analyzed the differences in overall femoral BMD (netavg) and in BMD in zones 1–7 according Gruen. There was no significant change in overall netavg BMD for both male and female patients (p> 0,05) comparing t1 and t3. We found a significant change in periprosthetic BMD in zone 7 (−6,62%, p< 0,05) in male patients and in zones 1, 6 and 7 (−8,7%/−5,1%/−14,2%, p< 0,01/0,05/0,01) in female patients. Discussion and Conclusion: The results of our study suggest that there are no clinically relevant changes in overall periprosthetic BMD around stable, uncemented straight stems in the long- term. However, continuous bone remodeling with slow but steady proximal bone loss occurs, predominantly in female patients. Once osseous integration is observed, stress shielding remains moderate and changes in periprosthetic BMD are limited to the metaphyseal region