A randomized prospective study comparing mobile-bearing against fixed-bearing PFC Sigma cruciate-retaining total knee arthroplasties with ten-year minimum follow-up.

AIMS: This study compares the PFC total knee arthroplasty (TKA) system in a prospective randomized control trial (RCT) of the mobile-bearing rotating-platform (RP) TKA against the fixed-bearing (FB) TKA. This is the largest RCT with the longest follow-up where cruciate-retaining PFC total knee arthroplasties are compared in a non-bilateral TKA study. PATIENTS AND METHODS: A total of 167 patients (190 knees with 23 bilateral cases), were recruited prospectively and randomly assigned, with 91 knees receiving the RP and 99 knees receiving FB. The mean age was 65.5 years (48 to 82), the mean body mass index (BMI) was 29.7 kg/m2 (20 to 52) and 73 patients were female. The Knee Society Score (KSS), Knee Society Functional Score (KSFS), Oxford Knee Score (OKS), Western Ontario and McMaster Universities Arthritis Index (WOMAC), and 12-Item Short-Form Health Survey Physical and Mental Component Scores (SF-12 PCS, SF-12 MCS) were gathered and recorded preoperatively, at five-years' follow-up, and at ten years' follow-up. Additionally, Knee Injury and Osteoarthritis Outcome Scores (KOOS) were collected at five- and ten-year follow-ups. The prevalence of radiolucent lines (RL) on radiographs and implant survival were recorded at five- and ten-year follow-ups. RESULTS: At the ten-year follow-up, the RP group (n = 39) had a statistically significant superior score in the OKS (p = 0.001), WOMAC (p = 0.023), SF-12 PCS (p = 0.019), KOOS Activities of Daily Living (ADL) (p = 0.010), and KOOS Sport and Recreation (Sport/Rec) (p = 0.006) compared with the FB group (n = 46). The OKS, SF-12 PCS, and KOOS Sport/Rec at ten years had mean scores above the minimal clinically important difference (MCID) threshold. There was no significant difference in prevalence of radiolucency between groups at five-years' follow-up (p = 0.449), nor at ten-years' follow-up (p = 0.08). Implant survival rate at 14 years postoperative was 95.2 (95% CI 90.7 to 99.8) and 94.7 (95% CI 86.8 to 100.0) for the RP and FB TKAs, respectively. CONCLUSION: At ten-year follow-up, the mobile-bearing knee joint arthroplasty had statistically and clinically relevant superior OKS, SF-12 PCS, and KOOS (Sport/Rec) than the fixed-bearing platform. No difference was seen in prevalence of radiolucent lines. There was a greater than 94% implant survival rate for both cohorts at 14 years. Cite this article: Bone Joint J 2018;100-B:1336-44.

Accuracy of a computer-assisted navigation system in resurfacing hip arthroplasty.

We developed a method to assess the accuracy of an image-free resurfacing hip arthroplasty navigation system in a proximal femur with normal and abnormal anatomy. A phantom lower limb allowed deformation in varus/valgus and ante-retroversion. At specific points during the simulated surgical procedure, information was compared between a digital caliper and the computer navigation system angular measurements. Repeated serial tests were undertaken. In the setting of normal anatomical alignment of the proximal femur, the mean error of the system characterised as the difference between the measured computer navigation and caliper angles was 0.6 degrees in the frontal plane and 3.4 degrees in the lateral plane. In the setting of abnormal anatomical alignment, the mean error was 0.4 degrees in the frontal plane and 2.1 degrees in the lateral plane. This is the first study designed to assess the accuracy of a femoral navigation system for resurfacing hip arthroplasty in normal settings and in the presence of angular deformity. The study demonstrates satisfactory in-vitro accuracy.

Evaluation of accuracy of an electromagnetic computer-assisted navigation system in total knee arthroplasty.

The objective of this study was to develop a method to assess the accuracy of an electromagnetic technology image-free navigation system for total knee arthroplasty in a leg with normal or abnormal mechanical alignment. An acrylic phantom leg was constructed to simulate tibia and femur deformation. Determination of actual leg alignment was achieved using a digital caliper unit. In the setting of normal alignment, the mean error of the system characterised as the difference between the measured computer navigation and digital caliper angles ranged between 0.8 degrees (frontal plane) and 1.5 degrees (lateral plane). In the setting of abnormal alignment, the mean error ranged between 0.4 degrees (frontal plane) and 1.6 degrees (lateral plane). Deformity had no demonstrable effect on accuracy. The study demonstrates satisfactory in vitro system accuracy in both normal and abnormal leg mechanical alignment settings.

Quantitative computer-assisted osteodensitometry in total hip arthroplasty.

Several factors can cause bone loss and fixation failure following total hip arthroplasty (THA), including polyethylene wear debris, implant micromotion and stress shielding. Various techniques have been used in an effort to detect bone density loss in vivo, all with varying success. Quantitative computed tomography (qCT)-assisted osteodensitometry has been shown to be useful in assessing the in vivo structural bone changes after THA. It has a high resolution, accuracy and reproducibility, thereby making it a useful tool for research purposes, and it is able to differentiate between cortical and cancellous bone structures and assess the bone/implant interface. This technique also provides valuable information about the pattern of stress shielding which occurs around the prosthesis and can show early bony changes, which may prove informative about the quality of implant fixation and surrounding bone adaptation. In conjunction with finite-element analysis, qCT is able to generate accurate patient-specific meshes on which to model implants and their effect on bone remodelling. This technology can be useful to predict bone remodelling and the quality of implant fixation using prostheses with different design and/or biomaterials. In the future, this tool could be used for pre-clinical validation of new implants before their introduction in the market-place.

Accuracy of a computer-assisted navigation system for total knee replacement.

The object of this study was to develop a method to assess the accuracy of an image-free total knee replacement navigation system in legs with normal or abnormal mechanical axes. A phantom leg was constructed with simulated hip and knee joints and provided a means to locate the centre of the ankle joint. Additional joints located at the midshaft of the tibia and femur allowed deformation in the flexion/extension, varus/valgus and rotational planes. Using a digital caliper unit to measure the coordinates precisely, a software program was developed to convert these local coordinates into a determination of actual leg alignment. At specific points in the procedure, information was compared between the digital caliper measurements and the image-free navigation system. Repeated serial measurements were undertaken. In the setting of normal alignment the mean error of the system was within 0.5 degrees . In the setting of abnormal plane alignment in both the femur and the tibia, the error was within 1 degrees . This is the first study designed to assess the accuracy of a clinically-validated navigation system. It demonstrates in vitro accuracy of the image-free navigation system in both normal and abnormal leg alignment settings.

Pre-formed articulating knee spacer in two-stage revision for the infected total knee arthroplasty.

We performed a prospective study to assess safety and effectiveness of a pre-formed articulating spacer made of gentamicin-impregnated acrylic cement in the management of infected total knee arthroplasty. Twenty-one consecutive patients with unilateral deep infection were treated by two-stage revision in two centres. Two patients were excluded, and 19 patients remained available for assessment. The mean implantation time of the spacer was 12 weeks. The rehabilitation programme between stages consisted in early range of motion exercises and partial weight bearing. Mean follow-up after removal of the spacer and insertion of the final prosthesis was 24 (range, 12-43) months. No patient had recurrence of infection at the latest follow-up. The mean Knee Society functional score during spacer management was rated 75 points and was rated 84 points at the latest follow-up. No device-related complication was observed.

Mechanical prophylaxis of deep-vein thrombosis after total hip replacement a randomised clinical trial.

Routine prophylaxis for venous thromboembolic disease after total hip replacement (THR) is recommended. Pneumatic compression with foot pumps seems to provide an alternative to chemical agents. However, the overall number of patients investigated in randomised clinical trials has been too small to draw evidence-based conclusions. This randomised clinical trial was carried out to compare the effectiveness and safety of mechanical versus chemical prophylaxis of DVT in patients after THR. Inclusion criteria were osteoarthritis of the hip and age less than 80 years. Exclusion criteria included a history of thromboembolic disease, heart disease, and bleeding diatheses. There were 216 consecutive patients considered for inclusion in the trial who were randomised either for management with the A-V Impulse System foot pump. We excluded 16 patients who did not tolerate continuous use of the foot pump or with low-molecular-weight heparin (LMWH). Patients were monitored for DVT using serial duplex sonography at 3, 10 and 45 days after surgery. DVT was detected in three of 100 patients in the foot-pump group and with six of 100 patients in the LMWH group (p < 0.05). The mean post-operative drainage was 259 ml in the foot-pump group and 328 ml in the LMWH group (p < 0.05). Patients in the foot-pump group had less swelling of the thigh (10 mm compared with 15 mm; p < 0.05). One patient developed heparin-induced thrombocytopenia. This study confirms the effectiveness and safety of mechanical prophylaxis of DVT in THR. Some patients cannot tolerate the foot pump.

Antibiotic-loaded bone cement spacers in two-stage management of infected total knee arthroplasty.

We reviewed the current use of spacers in the management of the infected knee prosthesis. There are two types of temporary spacers: block or non-articulating spacers and articulating or mobile spacers. Generally, spacers improve mobilisation and hasten recovery with shorter hospital stay between stages. Furthermore, spacers facilitate the second-stage procedure by maintaining joint space, and articulating spacers may also maintain range of motion. Last but not the least, the cost of spacers represents only a small fraction of the total expenses for management of infected knee arthroplasties.

[Mechanical versus drug prevention of thrombosis after total hip endoprosthesis implantation. A randomized, controlled clinical study]. / Mechanische versus medikamentöse Thromboseprophylaxe nach Totalhüftendoprothesenimplantation. Eine randomisierte, kontrollierte Klinische Studie.

Pharmacological prophylaxis is routinely applied after total hip replacement. Although it effectively reduces deep-vein thrombosis, side effects (bleeding, haematoma, swelling, thrombocytopenia) are not infrequent. Since in Germany use of foot pumps as only means of prophylaxis is unpopular, we investigated their efficacy and safety in a randomized study. 106 patients used either low molecular weight heparin (Fraxiparin, Sanofi-Synthelabo, Germany) or the foot-pump (A-V Impulse System, Orthofix, Mühltal, Germany), and were monitored for deep-vein thrombosis using serial duplex sonography on postoperative days 4, 12 and 45. Clinical observations included daily measurements of thigh circumference, recording of postoperative drainage amounts, and monitoring of wound healing. None of the 50 patients treated with the foot-pump developed deep-vein thrombosis, while 4 of the 50 patients (8 per cent) on pharmacological prophylaxis did so. Six patients stopped using the foot-pump during the study. One patient developed heparin-induced thrombocytopenia. Patients on mechanical prophylaxis had smaller amounts of drainage (mean 247 ml vs. 272 ml, p = 0.485) and significantly less swelling of the thigh (10 mm compared with 15 mm, p or = < 0.001), The good results in terms of prevention of thromboembolic complications and soft tissue swelling favour the general use of foot pumps as mechanical prophylaxis.

Anterior vertebral body screw pullout testing with the hollow modular anchorage system--a comparative in vitro study.

Pullout of implants at the proximal and distal ends of multilevel constructs represents a common spinal surgery problem. One goal concerning the development of new spinal implants is to achieve stable fixation together with the least invasive approach to the spinal column. This biomechanical study measures the influence of different modes of implantation and different screw designs, including a new monocortical system, on the maximum pullout strength of screws inserted ventrolaterally into calf vertebrae. The force pullout of eight different groups were tested and compared. Included were three bicortical used single screws (USS, Zielke-VDS, single KASS). To further increase pullout strength either a second screw (KASS) or a pullout-resistant nut can be added (USS with pullout nut). A completely new concept of anchorage represents the Hollow Modular Anchorage System (MACS-HMA). This hollow titanium implant has an increased outside diameter and is designed for monocortical use. Additionally two screw systems suitable for bicortical use were tested in monocortical mode of anchorage (USS, single KASS). We selected seven vertebrae equal in mean size and bone mineral density for each of the eight groups. The vertebral body and implant were connected to both ends of a servohydraulic testing machine. Displacement controlled distraction was applied until failure at the metal-bone-interface occurred. The maximum axial pullout force was recorded. Mean BMD was 312 +/- 55 mg CaHA/ml in cancellous bone and 498 +/- 98 mg CaHA/ml in cortical bone. The highest resistance to pullout found, measured 4.2 kN (KASS) and 4.0 kN (USS with pullout nut). The mean pullout strength of Zielke-VDS was 2.1 kN, of single KASS 2.5 kN, of MACS-HMA 2.6 kN and of USS 3.2 kN. There was no statistically significant difference (t-test, p > 0.05) between bicortical screws and the new monocortical implant. For the strongest fixation at the proximal or distal end of long spinal constructs the addition of a second screw or a pullout-resistant nut behind the opposite cortex offers even stronger fixation.

A computed tomography assessment of femoral and acetabular bone changes after total hip arthroplasty.

Using computed tomography-assisted (CT) osteodensitometry, we studied the bone changes that occurred in 12 patients at 2 weeks and again at 1 year after total hip arthroplasty with insertion of a press-fit acetabular cup and an uncemented femoral tapered stem. There was a greater decrease in full bone density (BD) lateral to the femoral stem when compared to the medial side, at the proximal end of the femur this difference was significant (-22.1% versus -16.2%) ( P<0.001). At the tip of the stem cortical BD had decreased between 2.3% and 1.9% only. Proximal to the cup, the cortical BD increased by about 3.4% ( P< or =0.05), while the full BD decreased markedly by 8% ( P< or =0.001). These changes represent a response to a decrease in regional bone stress induced by the presence of the press-fit implant, and this might be considered as retro-acetabular stress shielding. No focal bone resorption was found.

Alternative bearing surfaces in total hip arthroplasty: zirconia-alumina pairing. Contribution or caveat?

The aim of the present study was to evaluate the zirconia and alumina articulation in total hip arthroplasty in regard to clinical and radiological outcome. This is the first report concerning the clinical application of a hybrid ceramic articulation. Owing to ethical reasons, a limited number of patients was enrolled in the study. Ten consecutive patients with degenerative arthritis were randomly allocated after informed consent to hybrid total hip arthroplasty treatment using an alumina femoral head and an alumina acetabular liner (5 hips), or using a zirconia femoral head and an alumina acetabular liner (5 hips). The median age of patients at index operation was 57.8 years. Current criteria were used for clinical and radiological assessment. The mean follow-up was 5.1 years (5 to 5.3 years). No hip required revision, and no clinical and radiological differences were observed between the two groups of hips. The median preoperative Harris hip score was rated 55.3 points in the control group of hips with alumina head, and 55.6 in the group of hips with zirconia head. The median Harris hip score increased to 94.9 points at the time of follow-up in the control group, and 96 points in the zirconia group. No radiological signs of cup loosening or focal acetabular osteolysis were detected at follow-up. All stems showed stable fixation without radiolucent lines or focal osteolysis. Zirconia femoral heads and alumina acetabular liners have been successfully used in the present series of 5 total hip arthroplasties with a mean follow-up of 5.1 years. Nevertheless, the use of femoral heads made of zirconia in total hip arthroplasties remains an important clinical concern due to the potential genesis of wear microparticles which can lead to progressive osteolysis. Further in-vitro and in-vivo investigations are required to define the value of this alternative bearing surface.

[The MACS-HMA hollow screw. An alternative possibility for stable implant anchoring in the vertebral body also for long fusions]. / Die MACS-HMA-Hohltonne. Eine alternative Möglichkeit der stabilen Implantatverankerung im Wirbelkörper auch für langstreckige Fusionen.

Our biomechanical in vitro tests compared the stability of the MACS HMA (Aesculap, Tuttlingen) implants to three established systems. The MACS HMA is a modular system consisting of porous hollow titanium screws with an outer diameter of 12 mm for monocortical use. We report the preliminary results of MACS HMA used for correction of scoliosis. All other implant systems used are designed with bicortical screws; one is for application with two screws/two rods and one uses a pullout-resistant nut behind the opposite cortex to increase stability. Significantly increased motion in the craniocaudal direction was recognized for bicortical standard screws (20 +/- 17 microns) compared to MACS HMA (10 +/- 11 microns) or the dual screw system (12 +/- 6 microns). Two-tailed t-test showed significantly higher stability for the dual screw system (4.2 kN) and the system with pullout-resistant nut (4.0 kN) compared to all other systems (p < 0.025 or higher). Bicortical implants (2.1-3.2 kN) and MACS HMA (2.6 kN) did not reveal significant differences in pullout strength. All biomechanical tests and in vivo use demonstrated favorable performance of MACS HMA implants.

[Hemodynamics of the lower extremity with pneumatic foot compression. Effect on leg position]. / Hämodynamik der unteren Extremität mit pneumatischer Fusskompression. Einfluss der Beinlagerung.

External pneumatic compression of the foot is being used more and more to increase the venous blood flow in the lower limbs and thus reduce the risk of postoperative deep venous thrombosis. We have investigated the efficacy of the foot pump pneumatic compression device (A-V Impulse, Novamedix, Andover, England) in 10 healthy subjects and in 10 patients undergoing total hip arthroplasty. The velocity of venous blood flow in the common femoral artery was measured in the horizontal, Trendelenburg (head-down, foot-up) and reverse Trendelenburg (head-up and foot-down) positions using a duplex ultrasound unit (Sonoline Elegra, Siemens, Erlangen, Germany) with a 5 MHz linear array probe. Application of the foot pump produced an increase in venous blood flow velocity in all healthy subjects and in all patients. In healthy subjects the mean increase in the horizontal position was 31.18% (SD = 15.86%), and in the Trendelenburg position 20.72 (SD = 15.69%) (right limb). In the reverse Trendelenburg position, the foot pump produced a mean increase of 94.08% (SD = 55.00%). The difference is statistically significant (p < 0.005). In patients with a total hip arthroplasty, the mean increase in the horizontal position was 28.67% (SD = 9.95%), and in the Trendelenburg position 20.34% (SD = 17.85%) (operated limb). In the reverse Trendelenburg, the foot pump produced a mean increase of 91.55% (SD = 42.38%). The difference is statistically significant (p < 0.005). There was no noteworthy difference in results between the controls and patients. Pneumatic compression devices designed to reduce venous stasis are effective in decreasing the rate of deep venous thrombosis after surgery on the lower limb. The results of the present study show that the efficiency of the foot pump in increasing venous return is improved by adopting the reverse Trendelenburg position. This may increase its thromboprophylactic effect.

Fat and bone marrow embolism in total hip arthroplasty.

A number of cardiovascular and pulmonary complications have been reported to occur occasionally after insertion of a total hip prosthesis. Of the proposed causes of these reactions, the possibility of fat embolism has received considerable support. The increase in intramedullary pressure, produced by the mechanical compression of the femoral canal during the insertion of the stem, seems to be the decisive pathogenic factor for the development of emboli. Surgeons' proclivity to deny the clinical relevance of intraoperative emboli is directly related to their awareness of and their attempt to avoid this phenomenon. Depending on the preoperative clinical condition of the patient, the cardiorespiratory impairment may be subclinical for those with good reserve, or clinical for those with poor reserve. In cases with preexisting cardiorespiratory diseases, severe embolism can also lead to death. Moreover, tissue thromboplastin from bone marrow forced into the draining veins of the proximal femur during insertion of the stem leads to activation of the clotting cascade, lesions of the venous endothelium, and thrombogenesis. A correlation was found between the embolic events observed using transesophageal echocardiography and the cardiopulmonary function of the patients during the perioperative period. A modified surgical technique was designed to reduce the intramedullary pressure during insertion of the stem to prevent intraoperative embolic events. Surgical prevention of fat and bone marrow embolism can also reduce the incidence of postoperative deep vein thrombosis.

Initial stability of modular acetabular components. Comparative in-vitro study with polyethylene and ceramic liners.

Modular acetabular components with alumina ceramic liners are currently used in total hip arthroplasty, but concerns have emerged regarding their high stiffness, which could cause impairment of stability, stress-shielding phenomena, and loosening. The purpose of the present biomechanical investigation was to compare the in-vitro initial stability of a modular press-fit acetabular component using a polyethylene liner and using an alumina liner. The initial stability was investigated by measuring the micromotion between the implant and the acetabulum during the application of physiological load (2.39 kN). The micromotion of the acetabular component was investigated in 10 acetabuli using a polyethylene liner and in 10 acetabuli using an alumina liner. Micromotion was assessed at the level of the Os ilium, Os pubis, and Os ischium using 3 electromagnetic transducers. The transducers have a sensitivity of 1 micron and a range of measurement of 500 microns. All implants have been fixed on human pelves made of polyurethane. Measurement of implant micromotion showed stable conditions at the level of the three main sectors of the acetabulum during all tests. No statistically significant differences of results were observed between the group of specimens with polyethylene liner and the group of specimens with alumina liner. The mean micromotion values of the uncemented cups were similar to the mean micromotion values of 10 cemented cups investigated to achieve comparative data of stability. In conclusion, the modular acetabular components inserted using an alumina liner showed a satisfactory initial stability in-vitro. The results do not contrast with those achieved using the same cup inserted with a polyethylene liner.

The clinical relevance of embolic events detected by transesophageal echocardiography during cemented total hip arthroplasty: a randomized clinical trial.

UNLABELLED: The first aim of this prospective clinical study was to characterize the relationship between embolic events observed during cemented total hip arthroplasty using transesophageal echocardiography (TEE), and changes in cardiopulmonary function. The second aim was to assess the efficiency of a modified cementing technique that was developed to reduce the risk of embolism. The modification consists in a vacuum drainage placed in the proximal femur to reduce the increase of intramedullary pressure during insertion of the prosthesis. One hundred twenty patients were randomized into two groups. Group 1 received a total hip arthroplasty cemented conventionally, whereas Group 2 was cemented with the modified technique. Continuous TEE, hemodynamic monitoring, and blood gas analysis were done during the perioperative period. Severe embolic events were imaged during the insertion of the femoral component and the reduction of the hip joint. Embolism occurred in 93.3% of patients operated on with the conventional cementing technique, compared with 13.3% of patients operated on with the modified technique (P < 0.05). Intraoperative shunt values during insertion of the femoral component increased from 8.2% to 10.3% (P < 0.05) in Group 1 patients, whereas there was no significant change in Group 2 patients. We observed no clinical signs of fat embolism syndrome in any study patient. The results of the study indicate that embolic events observed using TEE can cause increased pulmonary shunt values during hip arthroplasty, especially in patients with systemic disease (ASA physical status III). The modified surgical technique effectively reduced the incidence of embolization during cemented hip arthroplasty. IMPLICATIONS: Use of conventional cementing techniques is associated with echocardiographic evidence of embolism in 93% of patients and with a significant increase in pulmonary shunting. The incidence of embolism and change in shunting are reduced with a modified cementing technique that limits increases in intramedullary pressure.

Clinical outcome and quantitative evaluation of periprosthetic bone-remodeling of an uncemented femoral component with taper design. A prospective study.

The rationale of uncemented taper stems is based on fixation in the proximal portion of the femoral diaphysis, a self-locking principle, and a low modulus of elasticity. The aim of this study was to evaluate a collarless femoral component designed to be a three-dimensional taper for press-fit insertion with regard to clinical outcome, efficacy of fixation, incidence of osteolysis, and periprosthetic bone-remodeling. The first 48 consecutive patients (50 hips) with osteoarthritis who had had primary total hip arthroplasty using the Cerafit Multicone stem and the Cerafit Triradius-M press-fit cup with alumina-alumina pairing (Ceraver Osteal, Paris, France) were followed-up for a mean of 2.3 years (2 to 2.5 years). The mean age of patients at index operations was 52.5 years. Current criteria were used for clinical and radiological assessment. Quantitative evaluation of periprosthetic bone-remodeling was prospectively assessed using computed tomography. Clinical and radiological follow-up was obtained in all hips. Forty-nine hips (98%) were clinically rated good or excellent, one hip (2%) was rated fair, owing to a persisting limp. The mean preoperative Harris Hip Score was rated 62, and it has improved to 93.5 at the time of follow-up. One hip (2%) had marked postoperative thigh pain. This pain had disappeared at 3-month follow-up. All stems showed radiological signs of stable fixation by bone ingrowth. No stem required revision. Thirty-four hips (68%) had either no change in femoral bone density or only patchy loss of bone density isolated to Gruen zones 1 and 7. Sixteen hips (32%) had some reduction of bone density isolated to zone 1. Radiolucencies without progression were found in zones 1 and 7 in 3 hips (6%), and in zone 1 alone in 3 other hips (6%). A slight cortical hypertrophy was seen in 3 hips (6%). Twenty-three hips (46%) developed radiographic appearance of bone apposition at the stem tip as partial pedestal (19 hips) and as complete pedestal (4 hips). No signs of cup loosening were detected at follow-up. Twenty-four patients (25 hips) were eligible for computed tomography. The mean decrease of the overall bone mineral density in the metaphyseal portion of the femur one year after insertion of the stem was rated 15.4%, and the mean decrease of the cortical bone mineral density was rated 17.2%. On the other hand, a mean decrease of the cortical bone mineral density of less than 5% was observed in the diaphyseal portion of the femur around the implant. The clinical and radiological results of the Cerafit Multicone stem at a mean follow-up of 2.3 years are very promising and do not contrast with those achieved using other uncemented stems with tapered design. Furthermore, results of quantitative evaluation of periprosthetic bone-remodeling were considered satisfactory favourably with others reported in the literature using stems inserted without cemented.