Cementless Spotorno tapered titanium stems

We evaluated the clinical and radiographic results of the first consecutive 154 implantations of a cementless, double-tapered straight femoral stem (cementless Spotorno (CLS), Sulzer Orthopedics) in 141 patients under the age of 55 (mean 47 (13-55)) years. After a mean follow-up of 12 (10-15) years, 11 patients (11 hips) had died and 7 (7 hips) could not be located. 5 patients (5 hips) underwent femoral revision—1 for infection, 1 for periprosthetic fracture and 3 for aseptic loosening of the stem. The overall survival rate of the stem was 97% at 12 years (95% confidence limits, 93%-100%), and survival with femoral revision for aseptic loosening as an end point 98 (95-100)%. The survival rate of the acetabular components was 78 (71-85) % after 12 years. The median Harris hip score at follow-up was 84 points. None of the patients had thigh pain. Radiolucent lines in Gruen regions 1 and 7 were present in 21 hips (17%). 2 hips had radiolucent lines in regions 2-6 on anteroposterior (AP) radiographs. No femoral osteolysis was detected.

The mid- to long-term survival with this type of femoral component is excellent and compares favorably with cemented stems in this age group. However, the high rate of cup loosening and the low Harris hip scores are a concern in this subgroup of young patients.     

Cementless Spotorno tapered titanium stems

We evaluated the clinical and radiographic results of the first consecutive 154 implantations of a cementless, double-tapered straight femoral stem (cementless Spotorno (CLS), Sulzer Orthopedics) in 141 patients under the age of 55 (mean 47 (13–55)) years. After a mean follow-up of 12 (10–15) years, 11 patients (11 hips) had died and 7 (7 hips) could not be located. 5 patients (5 hips) underwent femoral revision—1 for infection, 1 for periprosthetic fracture and 3 for aseptic loosening of the stem. The overall survival rate of the stem was 97% at 12 years (95% confidence limits, 93%–100%), and survival with femoral revision for aseptic loosening as an end point 98 (95–100)%. The survival rate of the acetabular components was 78 (71–85) % after 12 years. The median Harris hip score at follow-up was 84 points. None of the patients had thigh pain. Radiolucent lines in Gruen regions 1 and 7 were present in 21 hips (17%). 2 hips had radiolucent lines in regions 2–6 on anteroposterior (AP) radiographs. No femoral osteolysis was detected.

The mid- to long-term survival with this type of femoral component is excellent and compares favorably with cemented stems in this age group. However, the high rate of cup loosening and the low Harris hip scores are a concern in this subgroup of young patients.     

A retrieval study of capital hip prostheses with titanium alloy femoral stems.

We have examined 26 retrieved, failed titanium-alloy femoral stems. The clinical details, radiological appearances and the histology of the surrounding soft tissues in each patient were also investigated. The stems were predominantly of the flanged design and had a characteristic pattern of wear. A review of the radiographs showed a series of changes, progressive with time. The first was lateral debonding with subsidence of the stem. This was followed by calcar resorption and fragmentation or fracture of the cement. Finally, osteolysis was seen, starting with a radiolucency at the cement-bone interface and progressing to endosteal cavitation. Three histological appearances were noted: granulomatous, necrobiotic and necrotic. We suggest that an unknown factor, possibly related to the design of the stem, caused it to move early. After this, micromovement at the cement-stem interface led to the generation of particulate debris and fracture of the cement. A soft-tissue reaction to the debris resulted in osteolysis and failure of fixation of the prostheses.     

Radiolucent lines and osteolysis along tapered straight cementless titanium hip stems: a comparison of 6-year and 10-year follow-up results in 95 patients

Background The progress of radiolucent lines (RLs) around the stems of cementless hip endoprostheses and their implications for implant survival are unclear.

Patients and methods 150 consecutive total hip replacements (THRs) were performed between January and July 1993. The presence and development of RLs and osteolyses were monitored with a standardized special radiographic technique, and the results were compared at 6 and 10 years of follow-up in 95 patients.

Results At 6 years, RLs were detectable in 43 of 95 patients. RLs with an extension of 50% of the respective zone were present in 35 patients, almost all in Gruen zones 1 and 7. 2 patients presented with osteolysis. At 10 years, the RLs were almost identical—both in number and thickness. Only 1 additional osteolytic lesion had developed; no cup osteolyses were detected, and there was no significant polyethylene wear.

Interpretation The RLs detected at 6 years were virtually unchanged at 10 years. As they did not progress, they would not jeopardize implant stability. However, the osteolyses seen in 3 patients emphasize the importance of follow-up examinations.     

Radiolucent lines and osteolysis along tapered straight cementless titanium hip stems: A comparison of 6-year and 10-year follow-up results in 95 patients

Background?The progress of radiolucent lines (RLs) around the stems of cementless hip endoprostheses and their implications for implant survival are unclear.

Patients and methods?150 consecutive total hip replacements (THRs) were performed between January and July 1993. The presence and development of RLs and osteolyses were monitored with a standardized special radiographic technique, and the results were compared at 6 and 10 years of follow-up in 95 patients.

Results?At 6 years, RLs were detectable in 43 of 95 patients. RLs with an extension of 50% of the respective zone were present in 35 patients, almost all in Gruen zones 1 and 7. 2 patients presented with osteolysis. At 10 years, the RLs were almost identical—both in number and thickness. Only 1 additional osteolytic lesion had developed; no cup osteolyses were detected, and there was no significant polyethylene wear.

Interpretation?The RLs detected at 6 years were virtually unchanged at 10 years. As they did not progress, they would not jeopardize implant stability. However, the osteolyses seen in 3 patients emphasize the importance of follow-up examinations.     

Subsidence of monoblock and modular titanium fluted tapered stems in revision hip arthroplasty: A retrospective multicentre comparison study

BackgroundTapered, fluted, titanium (TFT) stems have shown good clinical outcomes in revision total hip arthroplasty (rTHA), however concerns exist regarding early subsidence. This study compares subsidence between a modern monoblock 3-degree and a modular 2-degree TFT stem in rTHA.MethodsA retrospective, international multicentre comparative study was conducted including 64 rTHA in 63 patients. A monoblock TFT stem was used in 37 cases and a modular TFT stem was used in 27 cases. Patient demographics, Paprosky femoral bone loss classification, bicortical contact and stem subsidence were recorded at minimum four week follow up.ResultsThere was no statistically significant difference in overall subsidence (p = 0.318) or the rate of subsidence >10 mm between stems. Mean subsidence was 2.13 mm in the monoblock group and 3.15 mm in the modular group. Two stems subsided >10 mm: one in each group. There was no difference in bicortical contact between groups (p = 0.98). No re-revisions were performed.ConclusionsWe found no difference in subsidence between the two stems. Surgeons may consider the use of monoblock stems in rTHA as they have comparably low rates of subsidence and eliminate the small but potentially catastrophic risk of implant fracture at modular junctions associated with modular stems.     

Subsidence of titanium straight stems in combination with highly viscous bone cement

Varying results and a high rate of subsidence have been reported for the straight femoral stem (M.E. Müller) made of titanium alloy. We examined subsidence in 135 titanium-alloy straight stems implanted with high viscosity cement after 68.8±11.5 months using a digital high-precision method (EBRA-FCA). One revised implant showed a subsidence of 14.6 mm and another 2.5 mm over 5 years. A third implant without migration was found to be loose. The 122 implants without loosening showed a mean subsidence of 0.1±0.1 mm, and focal osteolysis was seen in two. Altogether, we found subsidence of the titanium stems very small. The small subsidence may be related to the use of high viscosity bone cement.

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Résumé Des résultats variables et un taux élevé denfoncement ont été rapportés pour la tige droite fémorale (Müller) en alliage de titane. Nous avons examiné lenfoncement dans une série de 135 tiges droites en alliage de titane implantées avec un ciment de haute viscosité après 68,8±11,5 mois en utilisant une méthode numérique de haute précision (EBRA-FCA). Sur un délai de 5 ans un implant révisé a montré un enfoncement de 14.6 mm et un autre de 2.5 mm. Un troisième implant sans migration a été considéré descellé. 122 implants sans descellement ont montré un enfoncement moyen de 0.1±0.1 mm et une ostéolyse focale a été vue dans deux cas. Globalement nous avons trouvé très faible lenfoncement des tiges en alliage titane. Le petit enfoncement peut être en rapport avec lusage du ciment à haute viscosité.

     

Cementless Spotorno tapered titanium stems: excellent 10-15-year survival in 141 young patients

We evaluated the clinical and radiographic results of the first consecutive 154 implantations of a cementless, double-tapered straight femoral stem (cementless Spotorno (CLS), Sulzer Orthopedics) in 141 patients under the age of 55 (mean 47 (13-55)) years. After a mean follow-up of 12 (10-15) years, 11 patients (11 hips) had died and 7 (7 hips) could not be located. 5 patients (5 hips) underwent femoral revision-1 for infection, 1 for periprosthetic fracture and 3 for aseptic loosening of the stem. The overall survival rate of the stem was 97% at 12 years (95% confidence limits, 93%-100%), and survival with femoral revision for aseptic loosening as an end point 98 (95-100)%. The survival rate of the acetabular components was 78 (71-85)% after 12 years. The median Harris hip score at follow-up was 84 points. None of the patients had thigh pain. Radiolucent lines in Gruen regions 1 and 7 were present in 21 hips (17%). 2 hips had radiolucent lines in regions 2-6 on anteroposterior (AP) radiographs. No femoral osteolysis was detected. The mid- to long-term survival with this type of femoral component is excellent and compares favorably with cemented stems in this age group. However, the high rate of cup loosening and the low Harris hip scores are a concern in this subgroup of young patients.     

Patterns of osseointegration and remodeling in femoral revision with bone loss using modular, tapered, fluted, titanium stems

Radiographic signs of osseointegration with the use of fluted, tapered, modular, titanium stems in revision hip arthroplasty with bone loss have not been previously categorized. Serial radiographs of 64 consecutive hips with mean follow-up of 6.2 years were retrospectively reviewed. Bone loss was classified as per Paprosky classification, osseointegration was assessed according to a modified system of Engh et al, and Harris Hip Score was used to document pain and function. Seventy-four percent of the hips had type 3 or 4 bone loss. All stems were radiographically osseointegrated. Early minor subsidence was seen in 6.2% of the hips; definite bony regeneration, 73% of the hips; and stress shielding, 26% of the hips. These osseointegration patterns were different from those described for extensively porous-coated cobalt-chromium stems and had a bearing on the evaluation of fixation of these stems.     

Biological fixation of hydroxyapatite-coated versus grit-blasted titanium hip stems: a canine study

BACKGROUND: The purpose of the study was to evaluate the influence of a proximal hydroxyapatite (HA) coating in comparison with a grit-blasted titanium surface of an anatomic hip stem in an animal model over a maximum duration of 2 years. METHODS: Thirty adult dogs underwent implantation of either a proximally HA-coated or a grit-blasted anatomic titanium stem. The animals were clinically evaluated for their walking ability, and serial radiographs were taken. The femora were assessed histomorphologically at set time points from 6 weeks to 2 years postoperatively. Undecalcified thin section specimens through the proximal and distal portion of the coating or grit blasting were prepared. The percentage of implant surface with direct bone contact without connective tissue involvement was determined. RESULTS: Radiographically, animals with uncoated prostheses showed characteristic signs of loosening more frequently. Histomorphometrically, an average of 65% of the surface of HA-coated implants had bone contact, but only 14.7% of the surface of grit-blasted prostheses ( p=0.0001). There was no relationship between bone contact and the duration of implantation of the prosthesis, either for the coated or for the uncoated prostheses. HA coating enhances osseointegration of an anatomic hip stem. CONCLUSION: Anatomic stems with rounded design require a surface coating or surface structure, since the mere grit-blasting of the titanium surface does not ensure osseointegration in this animal model.     

Total hip arthroplasty with satin finish, tapered stems

Subsidence of femoral hip prostheses with a rough surface has been associated with osteolysis and loosening. However, recent evidence has suggested that smooth-finish tapered stems may not incur these problems. An experimental monobloc satin finish, tapered femoral component was designed to subside within the cement. There were 49 femoral components implanted, and patients averaged a 1.8-mm subsidence at the prosthesis-cement interface with a follow-up of 6.76 years. There were no failures attributable to aseptic loosening at the cement-bone interface. This study supports the use of a satin finish, tapered femoral component in cemented total hip arthroplasty.     

Clinical significance of corrosion of cemented femoral stems in metal-on-metal hips: a retrieval study

Purpose

The clinical significance of corrosion of cemented femoral stems is unclear. The purpose of this retrieval study was to: (1) report on corrosion at the stem-cement interface and (2) correlate these findings with clinical data.

Methods

We analysed cemented stems (n?=?36) composed of cobalt-chromium (CoCr) and stainless steel (SS) in a series of revised metal-on-metal hips. We performed detailed inspection of each stem to assess the severity of corrosion at the stem-cement interface using a scale of 1 (low) to 5 (severe). We assessed the severity of corrosion at each stem trunnion and measured wear rates at the head taper and bearing surfaces. We used non-parametric tests to determine the significance of differences between the CoCr and SS stems in relation to: (1) pre-revision whole blood Co and Cr metal ion levels, (2) trunnion corrosion, (3) bearing surface wear and (4) taper material loss.

Results

The corrosion scores of CoCr stems were significantly greater than SS stems (p?<?0.01). Virtually all stem trunnions in both alloy groups had minimal evidence of corrosion. The median pre-revision Co levels of implants with CoCr stems were significantly greater than the SS stems (p?<?0.01). There was no significant difference in relation to pre-revision Cr levels (p?=?0.521). There was no significant difference between the two stem types in relation to bearing wear (p?=?0.926) or taper wear (p?=?0.148).

Conclusions

Severe corrosion of cemented femoral stems is a common finding at our retrieval centre; surgeons should consider corrosion of CoCr stems as a potential source of metal ions when revising a hip.

     

Total hip arthroplasty using two different cementless tapered stems.

The authors report their 15-year experience with primary total hip arthroplasty using collarless, tapered, porous-coated femoral stems (Trilock and Taperloc) in patients with osteoarthritis, rheumatoid arthritis, and in octogenarians. Excellent clinical results were achieved in all groups at latest followup. For the patients with Trilock stems, Taperloc stems, and patients who were octogenarians and patients with rheumatoid arthritis, Charnley pain scores were 5.6, 5.5, 5.7, and 5.7; Charnley function scores were 5.2, 5.1, 4.2, and 5.3; Harris hip scores were 92, 92, 82, and 93 points, respectively. There was a 2% rate of thigh pain with the Trilock, 4% with Taperloc, 4% in octogenarians, and 2% in patients with rheumatoid arthritis. In 96% of the patients in the Trilock group, in 100% of the patients in the Taperloc group, in 100% of the patients who were octogenarians, and in 100% of the patients with rheumatoid arthritis, femoral components showed radiographic evidence of bone ingrowth. There were six (12%) femoral component revisions in the Trilock group (all secondary to nonmodularity of the component at the time of acetabular revision), one femoral component revision in the Taperloc group and no femoral component revisions in the patients who were octogenarians or who had rheumatoid arthritis. Design features (collarless tapered wedge fit, circumferentially porous-coated) virtually ensure bone ingrowth and are thought to be responsible for the excellent clinical results and longevity.     

Prospective,comparative study of cemented,smooth-surfaced titanium stems and polish-surfaced,stainless steel stems at a minimum follow-up of 10 years

European Journal of Orthopaedic Surgery & Traumatology - Excellent results have been reported with cemented total hip arthroplasty (THA) using both smooth-surfaced and polished-surfaced stems....     

Monoblock or modular tapered stems: Making the right choice

Tapered fluted titanium stems (TFTS) allow stable fixation in diaphyseal bone, helping the revision arthroplasty surgeon obtain a satisfactory clinical outcome. Monoblock and modular TFTS have shown similar benefits with regards to survivorship and hip-specific outcome measures. Monoblock stems have a propensity for asymptomatic subsidence, whereas modular stems carry a modest risk of implant failure at the stem–body modular junction. An experienced revision surgeon can use a monoblock TFTS can be used for most cases. The infrequent revision arthroplasty surgeon, on the other hand, is best suited to use a modular TFTS, especially when a trans-femoral osteotomy is planned.     

Minimum 10-year results of a tapered, titanium, hydroxyapatite-coated hip stem: an independent review

The performance of, and periprosthetic bone response to, a tapered, titanium (Ti6Al4V), hydroxyapatite-coated femoral hip prosthesis was evaluated at minimum of 10 years of follow-up. Data were prospectively collected on 147 consecutive primary hip arthroplasties performed in 133 patients by a single surgeon during a 2-year interval. Clinical and radiographic analyses of 96 hips in 86 patients were independently performed by 2 surgeons who were not involved in the care of these patients. There were no cases of aseptic loosening of the femoral component. Subsidence and stress shielding occurred in 5% and 2% of cases, respectively, and was not clinically significant. In all 15 hips that required revision of the acetabular component, the femoral component was found to be well fixed, without any occurrence of distal osteolysis. This femoral design provided reliable osseointegration that was durable at a mean of 11.5 years of follow-up.     

The use of hydroxyapatite on press-fit tapered femoral stems

The advantage of an HA coating includes superior proximal femoral osteointegration and reduced thigh pain, reduced subsidence risk, reduced distal wear particle migration, and better preservation of periprosthetic bone quality. Furthermore, the survivorship and clinical outcomes are at least comparable to cemented and uncoated uncemented systems without any substantial deleterious effect of the HA coating like third-body wear or late failures. In our opinion, these advantages justify the increased cost. With over 20 years of favorable cumulative data, the continued use of HA can be recommended as an effective and reliable adjunct to cementless tapered femoral fixation in primary THA.     

The use of tapered stems for femoral revision surgery

From a biomechanical view point, cementless fixation of a tapered stem has some advantages compared with other techniques to treat severe proximal femoral bone loss in reconstructive hip surgery. We reviewed 129 consecutive revision arthroplasties of the femoral component in which the tapered Wagner self-locking revision stem was used. The mean followup of patients without rerevision of the stem was 8.1 years (range, 5.1-14.1 years). Six revision stems required rerevision (malpositioning, one stem; subsidence, one stem; periprosthetic fracture, one stem; deep infection, three stems) between 0.13 and 4.6 years postoperatively. Using removal of the stem for any cause as the end point, the cumulative survival at 14.1 years was 95.2%. The average Merle d'Aubigné score improved from 7.7 points preoperatively to 14.4 points at the latest followup. Because of new bone formation, the most recent radiographs showed clear, good, or excellent restoration of the proximal femur in 88% of patients. Considering possible late complications such as osteolysis of the femur, aseptic loosening, periprosthetic fracture, and late infection, the shortest stem that ensures sufficient mechanical stability should be used. It may be easier to achieve high primary stability in short stems with a tapered design than with other short stem designs.     

Uncemented femoral revision arthroplasty using a modular tapered,fluted titanium stem

Background and purpose — Due to the relative lack of reports on the medium- to long-term clinical and radiographic results of modular femoral cementless revision, we conducted this study to evaluate the medium- to long-term results of uncemented femoral stem revisions using the modular MRP-TITAN stem with distal diaphyseal fixation in a consecutive patient series.

Patients and methods — We retrospectively analyzed 163 femoral stem revisions performed between 1993 and 2001 with a mean follow-up of 10 (5–16) years. Clinical assessment included the Harris hip score (HHS) with reference to comorbidities and femoral defect sizes classified by Charnley and Paprosky. Intraoperative and postoperative complications were analyzed and the failure rate of the MRP stem for any reason was examined.

Results — Mean HHS improved up to the last follow-up (37 (SD 24) vs. 79 (SD 19); p < 0.001). 99 cases (61%) had extensive bone defects (Paprosky IIB–III). Radiographic evaluation showed stable stem anchorage in 151 cases (93%) at the last follow-up. 10 implants (6%) failed for various reasons. Neither a breakage of a stem nor loosening of the morse taper junction was recorded. Kaplan-Meier survival analysis revealed a 10-year survival probability of 97% (95% CI: 95–100).

Interpretation — This is one of the largest medium- to long-term analyses of cementless modular revision stems with distal diaphyseal anchorage. The modular MRP-TITAN was reliable, with a Kaplan-Meier survival probability of 97% at 10 years.     

Reverse tapered vs. straight PTFE (Gore-Tex) grafts in dogs

Reversed Autogenous Saphenous Vein (RASV) remains the material of choice in infrainguinal arterial bypass. A characteristic of RASV not seen in other grafts is its reverse tapered (RT) configuration. The purpose of this study was to investigate this geometric configuration. Straight 6 mm PTFE (gore-tex) grafts (SG) and 4-7 mm reverse tapered PTFE (gore-tex) grafts (RTG) were both implanted in the aorto-iliac position in 16 mongrel dogs. Specimens of surviving dogs were examined by the usual methods. In terms of absolute patency, 9 of 14 RTG (64%) and 5 of 14 SG (36%) P = 0.05, anastomotic thrombus formation 6 of 14 (43%) RTG vs. 10 of 14 (71%) SG P = 0.05 and in midgraft thrombus deposition P = 0.025 the RTG performed significantly better than the SG. In light of these results and other considerations, the reverse tapered configuration merits clinical investigation with other materials and in other species.