High risk of early periprosthetic fractures after primary hip arthroplasty in elderly patients using a cemented,tapered, polished stem

Background and purpose — Postoperative periprosthetic femoral fracture (PPF) after hip arthroplasty is associated with considerable morbidity and mortality. We assessed the incidence and characteristics of periprosthetic fractures in a consecutive cohort of elderly patients treated with a cemented, collarless, polished and tapered femoral stem (CPT).

Patients and methods — In this single-center prospective cohort study, we included 1,403 hips in 1,357 patients (mean age 82 (range 52–102) years, 72% women) with primary osteoarthritis (OA) or a femoral neck fracture (FNF) as indication for surgery (367 hips and 1,036 hips, respectively). 64% of patients were ASA class 3 or 4. Hip-related complications and need for repeat surgery were assessed at a mean follow-up time of 4 (1–7) years. A Cox regression analysis was used to evaluate risk factors associated with PPF.

Results — 47 hips (3.3%) sustained a periprosthetic fracture at median 7 (2–79) months postoperatively; 41 were comminute Vancouver B2 or complex C-type fractures. The fracture rate was 3.8% for FNF patients and 2.2% for OA patients (hazard ratio (HR) = 4; 95% CI: 1.3–12). Patients > 80 years of age also had a higher risk of fracture (HR = 2; 95% CI: 1.1–4.5).

Interpretation — We found a high incidence of early PPF associated with the CPT stem in this old and frail patient group. A possible explanation may be that the polished tapered stem acts as a wedge, splitting the femur after a direct hip contusion. Our results should be confirmed in larger, registry-based studies, but we advise caution when using this stem for this particular patient group.     

Polished,Collarless, Tapered,Cemented Stems for Primary Hip Arthroplasty May Exhibit High Rate of Periprosthetic Fracture at Short-Term Follow-Up

Background

Cemented stems are designed to follow 1 of 2 principles of fixation: composite beams or slide taper. Stems in the latter category have a collarless, polished, tapered (CPT) design and subside into the cement mantle, creating hoop stresses. We compared the rate of periprosthetic fracture (PPF) of stem designed with these 2 principles of fixation. In addition, we examined radiographic factors that may predispose to the development of PPF.

A unique peri-prosthetic fracture pattern in well fixed femoral stems with polished, tapered, collarless design of total hip replacement

Peri-prosthetic fractures (PPF) are a recognised complication following hip arthroplasty. Prosthesis design and type influence PPF pattern. Surgeons rely on classification systems, such as the Vancouver, to aid treatment planning. This study highlights a specific fracture pattern that occurs with cemented well-fixed polished, tapered, collarless (PTC) stems. We reviewed a consecutive series of 21 PPF around well fixed PTC stems. The majority of the fractures were classified pre-operatively as Vancouver B2 (14/21), but there were also B1 (6/21) and A type fractures. The B2 fractures had common radiological and intra-operative findings: a spiral fracture with extensive fragmentation of bone and cement, debonding of cement from the implant, cement fracture, and a well-fixed cement-bone interface. Reconstruction of these fractures was more difficult than suggested by the radiographs. Two of the six patients who were considered to have a Vancouver B1 fracture underwent open reduction and internal fixation (ORIF), and had treatment-related complications. Retrospective review of the radiographs showed subtle features, such as subsidence of the stem into the centraliser, that are characteristic of a B2 fracture pattern. In summary, it is important to recognise this fracture pattern around secure PTC stems in order to prevent misinterpretation of the fracture as a Vancouver B1 rather than a B2, leading to failure of treatment, and to alert the surgeon that complex reconstruction will be required because of the extensive fragmentation.     

Equivalent hip stem fixation by Hi-Fatigue G and Palacos R + G bone cement: a randomized radiostereometric controlled trial of 52 patients with 2 years’ follow-up

Background and purpose — Long-term fixation of cemented femoral stems relies on several factors including cement adhesion and fatigue. Hi-Fatigue is a newer third-generation bone cement with low-viscosity properties at room temperature, good mechanical strength, and stable bone–cement interface in a laboratory testing environment. Palacos bone cement has excellent 10-year survival and is considered gold standard. We compared stem subsidence after fixation with Hi-Fatigue and Palacos bone cements using radiostereometry.

Patients and methods — In a patient-blinded randomized controlled trial, 52 patients (30 women) at mean age 76 years (71–87) with osteoarthrosis and no osteoporosis received Hi-Fatigue G or Palacos R?+?G cement fixation of collarless, polished, double-tapered stems (CPT). Tantalum beads were inserted in the periprosthetic bone. Supine stereoradiographs were obtained postoperatively, 3 months, 6 months, 1 year, and 2 years after surgery. Oxford Hip Score (OHS) and VAS pain were recorded preoperatively and 1 and 2 years after surgery. Cement working times and properties were registered.

Results — At 2 years, mean stem subsidence of 1.12?mm (95% CI 0.96–1.29) for Hi-Fatigue and 1.19?mm (CI 1.03–1.34) for Palacos was similar. Likewise, stem version was comparable between cement groups. Mean OHS and VAS pain were similar between cement groups.

Cement working times were similar between cement groups, but the mean curing time was longer for Hi-Fatigue (13.7?min) than for Palacos (11.6?min).

Interpretation — We found similar and generally low migration of CPT femoral stems inserted with Hi-Fatigue and Palacos bone cement until 2 years’ follow-up, which indicates a good long-term survival of polished taper femoral stems inserted with both cement types.

Trial registration: ClinicalTrials.gov identifier: NCT01289834.     

Outcomes following osteosynthesis of periprosthetic hip fractures around cemented tapered polished stems

We retrospectively reviewed outcomes of 79 patients with periprosthetic hip fractures around cemented tapered polished stem (CTPS) implants treated with osteosynthesis between January 1997 and July 2011. All patients underwent open reduction and fixation using a broad dynamic compression plate (DCP).Seventy two (91%) of fractures united. There were seven (9%) non-unions with failure of metal work, three (4%) as a result of infection and four (5%) due to mechanical failure. Significant subsidence (>5 mm) of the implant was seen in seven (9%) of cases. Ten (13%) cases developed post-operative infection. Non-anatomic reduction and infection were identified as predictors of poor outcome.This is the largest series of a very specific group of periprosthetic fractures treated with osteosynthesis. Open reduction internal fixation with a broad dynamic compression plate for patients with periprosthetic hip fractures around the tip of cemented tapered polished stems is a suitable treatment provided there is no bone loss and the fracture can be precisely, anatomically, reduced and adequately fixed.     

Cement Mantle Quality and Stem Alignment in Cemented Collarless Polished Tapered Stems Implanted via the Direct Anterior and Direct Lateral Approaches: A Single Institution Experience

BackgroundThe aim of this study was to compare the stem alignment and the quality of cement mantle of collarless polished tapered cemented stems inserted through the direct anterior approach (DAA) and the direct lateral approach (DLA).MethodsA comparative retrospective study of 232 hybrid total hip arthroplasties using a cemented collarless polished tapered stem through either the DAA (n = 147) or DLA (n = 85) was performed. Radiographic evaluation included stem alignment, cement mantle quality, and cement mantle thickness.ResultsOn anteroposterior radiographs, stems implanted through the DLA were more likely to be in neutral alignment, than those implanted through the DAA (83.5%[n = 71] versus 71.4% [n = 105]; P = <.001). No difference between approaches was noted for stem alignment on lateral radiographs or cement mantle quality. Multivariate analysis revealed factors associated with suboptimal cement mantle and included Dorr type B or C femur as well as male gender. A mean cement mantle thickness ≥2mm was achieved in all Gruen zones for both approaches.ConclusionIn our series, the DAA was associated with a higher incidence of coronal plane stem malalignment compared to the DLA when using cemented tapered polished femoral components for total hip arthroplasty. No difference in lateral stem alignment or cement mantle quality was found.     

Total hip arthroplasty with a cemented, polished, collared femoral stem and a cementless acetabular component. A follow-up study at a minimum of ten years

BACKGROUND: Recent studies have suggested that cemented femoral components with a polished surface may provide superior long-term fixation when compared with femoral components with a roughened surface. The purpose of this study was to evaluate the results of total hip arthroplasty with a cemented femoral component with a polished surface finish and compare them with the results of total hip arthroplasty performed with a similar design of cemented femoral component with a rougher surface finish. METHODS: We retrospectively reviewed a consecutive group of 132 patients (149 hips) in whom primary total hip arthroplasty had been performed by one surgeon using a cemented collared femoral component with a polished (0.1-microm Ra) surface finish and a cementless acetabular component. Ninety-eight patients (115 hips) were followed for a minimum of ten years. We compared the survivorship of this prosthesis with that of a femoral component of similar design but with rougher surfaces (matte or grit-blasted). RESULTS: No polished stems were revised because of aseptic loosening or demonstrated radiographic evidence of loosening; however, eight hips (5.4%) with a polished stem demonstrated osteolysis distal to the greater or lesser tro-chanter. In contrast, six stems (2.0%) with a matte surface finish of 0.8-microm Ra were revised because of aseptic loosening, and an additional five stems were seen to be loose radiographically. Eleven stems (9.2%) with a grit-blasted surface finish of 2.1-microm Ra were revised because of aseptic loosening, and an additional four stems were seen to be loose radiographically. The difference in the prevalence of revision due to aseptic loosening between the group with the 0.1-microm Ra surface and the group with the 2.1-microm Ra surface was significant (p = 0.001), as was the difference between the prevalence of revision due to aseptic loosening between the group with the 0.8-microm Ra surface and the group with the 2.1-microm Ra surface (p = 0.001). No cups were revised because of aseptic loosening, and one hip had radiographic signs of acetabular loosening. CONCLUSIONS: This study demonstrated excellent durability of a prosthesis consisting of a cemented, collared, polished femoral component and a cementless acetabular component. While no hips were revised because of aseptic loosening, distal femoral osteolysis was observed in eight hips (5.4%), a higher prevalence than has been reported by others after similar durations of follow-up of tapered, collarless, polished femoral components.     

Collarless polished tapered stem: clinical and radiological follow-up over 5 years

The clinical and radiologic outcome of a cemented, polished, tapered stem (CPT), implanted using contemporary cementing techniques in 108 consecutive operated hips in 100 patients (68 women and 32 men, aged 19 to 83 years at the time of surgery [mean, 65 years]) was assessed after >5 years. The Harris hip scores were good or excellent in 96% of the patients. Stem subsidence measured by the computer-assisted method described by Braud and Freeman was at a mean rate of 0.44 mm/y, 1.08 mm during the first year, and stabilizing to a mean total of 2.18 mm at >5 years. Subsidence was related inversely to the completeness of the cement mantle but did not correlate with the clinical or radiologic outcome. This study confirms that collarless, polished, tapered stems subside within the cement mantle but without loosening and that the CPT performs at least as well as the Exeter stem.     

Femoral stem dislodgement during bipolar hemiarthroplasty dislocation

Bipolar hemiarthroplasty remains a treatment option for displaced femoral neck fractures in elderly patients without pre-existing hip disease. Implant-related complications associated with this procedure include acetabular erosion, dislocation, disassembly of the modular components, polyethylene debris-induced osteolysis, metallosis from outer cup impingement, and femoral component loosening. This article presents a case of a patient in whom the polished collarless tapered femoral stem dislodged out of the cement mantle during traumatic bipolar hemiarthroplasty dislocation, 28 days after the index procedure. This complication, associated with bipolar hemiarthroplasty dislocation, was adequately managed by driving the stem back to the original cement mantle, followed by reduction of bipolar component dislocation and placing bone cement over the shoulder of the femoral stem to prevent a new dislodgement episode. Although rare, dislodgement of cemented polished collarless tapered stems from the cement mantle has been recently reported either during dislocation or, more frequently, as a complication of reduction of a dislocated total hip arthroplasty. However, its occurrence in association with bipolar hemiarthroplasty dislocation was not found to have been reported in the literature. The occurrence of femoral stem dislodgement during bipolar hemiarthroplasty dislocation should be considered as a possible complication of such a procedure and may be prevented by routinely placing bone cement over the shoulder of the femoral implant.     

Collarless polished tapered stem: clinical and radiological results at a minimum of ten years' follow-up

We retrospectively reviewed 175 patients (191 hips) who had undergone primary cemented total hip replacement between November 1992 and November 1995 using a collarless polished double-tapered femoral component after a minimum of ten years (mean 11.08; 10 to 12.8). All stems were implanted using contemporary cementing techniques with a distal cement restrictor, pressurised lavage, retrograde cementing with a gun and proximal pressurisation. Clinical outcome was assessed using the Harris Hip score. Radiological analysis was performed on calibrated plain radiographs taken in two planes. Complete radiological data on 110 patients (120 hips) and clinical follow-up on all the surviving 111 patients (122 hips) was available. The fate of all the hips was known. At final follow-up, the mean Harris Hip score was 86 (47 to 100), and 87 of 116 patients (75%) had good or excellent scores. Survival with revision of the stem for aseptic loosening as the endpoint was 100%; and survival with revision of the stem for any reason was 95.9% (95% confidence interval 87.8 to 96.8) at ten years. All the stems subsided vertically at the stem-cement interface in a predictable pattern, at an overall mean rate of 0.18 mm per year (0.02 to 2.16), but with a mean rate of 0.80 mm (0.02 to 2.5) during the first year. The mean total subsidence was 1.95 mm (0.21 to 24). Only three stems loosened at the cement-bone interface. There was excellent preservation of proximal femoral bone stock. There was a high incidence of Brooker III and IV heterotopic ossification affecting 25 patients (22%). The collarless polished tapered stem has an excellent clinical and radiological outcome at a minimum of ten years' follow-up. The pattern and magnitude of subsidence of the stem within the cement mantle occurred in a predictable pattern, consistent with the design philosophy.     

Total hip arthroplasty for acute femoral neck fractures using a cementless tapered femoral stem

The purpose of this study was to evaluate the osseointegration potential and implant-related complications of cementless total hip arthroplasty with a titanium alloy collarless, tapered, wedge-shaped femoral stem with a proximal circumferential plasma-spray coating in patients with acute hip fractures. The cohort consists of 85 patients with a mean age of 78.1 years. The mean duration of follow-up was 3.8 years. Total hip arthroplasty conferred significant improvement in function for all patients. All femoral components were stable with evidence of bone ingrowth (84 hips) or fibrous fixation (1 hip). Mild thigh pain was present in 3 patients. The complications included dislocation (3 cases), intraoperative femoral fracture (2 cases), and periprosthetic femoral fracture in the postoperative period (1 case). There was one reoperation for revision of the femoral component in the patient with a periprosthetic fracture. There were 25 (29%) deaths. Cementless total hip arthroplasty using a tapered proximally coated femoral stem is a viable option for the treatment of a displaced hip fracture and preexistent arthritis.     

The effect of a collar and surface finish on cemented femoral stems: a prospective randomised trial of four stem designs

Purpose

The optimal design for a cemented femoral stem remains a matter of debate. Over time, the shape, surface finish and collar have all been modified in various ways. A clear consensus has not yet emerged regarding the relative merits of even the most basic design features of the stem. We undertook a prospective randomised trial comparing surface finish and the effect of a collar on cemented femoral component subsidence, survivorship and clinical function.

Methods

One hundred and sixty three primary total hip replacement patients were recruited prospectively and randomised to one of four groups to receive a cemented femoral stem with either a matt or polished finish, and with or without a collar.

Results

At two years, although there was a trend for increased subsidence in the matt collarless group, this was not statistically significant (p = 0.18). At a mean of 10.1 years follow-up, WOMAC scores for the surviving implants were good, (Range of means 89–93) without significant differences. Using revision or radiographic loosening as the endpoint, survivorship of the entire cohort was 93 % at 11 yrs, (CI 87–97 %). There were no significant differences in survivorship between the two groups with polished stems or the two groups with matt stems. A comparison of the two collarless stems demonstrated a statistically significant difference in survivorship between polished (100 %) and matt (88 %) finishes (p = 0.02).

Conclusions

In the presence of a collar, surface finish did not significantly affect survivorship or function. Between the two collarless groups a polished surface conferred an improved survivorship.     

The relationship between stem subsidence and improvement in the radiolucency in polished tapered stems

We studied the relationship between stem subsidence and improvement in the initial radiolucency at the bone-cement interface in polished- and rough-surface stems. Stem subsidence was seen in 34 of 42 hips (81.0%), and improvement in the initial radiolucency was seen in 15 hips (35.7%) in collarless polished tapered stems at 1 year after operation. In polished stems, stem subsidence in cases with improvement in the initial radiolucency was significantly greater than in those with no change (average 1.12 mm and 0.48 mm, P<0.005). In rough-surface stems partially coated with polymethylmethacrylate (VerSys Cemented Plus), no stem subsidence and no improvement in the initial radiolucency was seen. In polished stems, stem subsidence leads to cement creep and compressive force on the bone-cement interface and can improve the initial radiolucency.     

Cement-within-cement stem exchange using the collarless polished double-taper stem

The clinical and radiographic outcomes of the cement-within-cement femoral stem exchange technique at revision hip arthroplasty were determined. Twenty-three revisions with a collarless polished double-taper stem design were prospectively monitored at up to 12 years. The most common indications for revision were recurrent dislocation and acetabular revision. Radiographic stem subsidence was measured by the Ein Bild Röentgen Analyse method. There was no stem re-revision and no radiographic loosening. Stem within cement subsidence, an intentional design feature of this stem, averaged 0.8 mm (range, 0-2 mm). The average subsidence was similar to that in primary hip arthroplasty. The excellent long-term results of cemented collarless polished taper stems for primary and revision hip arthroplasty can be extended even further by cement-within-cement exchange, which preserves the femur.     

Cemented collarless (exeter-CPT) versus cementless collarless (PCA) femoral components: A 2- to 14-year follow-up evaluation

The purpose of this study was to compare the intermediate results of total hip arthroplasty with a cemented, collarless, femoral prosthesis design (Exeter, Howmedica, Middlesex, UK and CPT, Zimmer, Warsaw, IN) with those of a cementless, collarless, porous-coated femoral component (PCA, Howmedica). A total of 151 hips in 128 patients were reviewed. In the cemented group, 85 Exeter-CPT prostheses were used in 71 patients with an average follow-up period of 6.5 years. In the uncemented group, 66 PCA prostheses were placed in 57 patients with an average follow-up period of 7 years. Harrington hip scores improved from 50.1 to 80.7 for the PGA group and from 49.5 to 87.3 for the Exeter-CPT group. The patient satisfaction rates were 89 and 96%, respectively. Sixty-eight patients with Exeter or CPT prostheses had excellent function and no significant thigh pain after 2 years. One Exeter stem was revised 10 years after the primary surgery because of localized osteolysis due to cement defect. Two Exeter sockets were revised because of aseptic loosening. In the PCA group, the incidence of thigh pain that persisted beyond 2 years was 39.4%, and there were high incidences of distal cortical hypertrophy (66.6%) and bead loosening (45.5%). Sixteen hips were revised for aseptic stem loosening, uncontrollable thight pain, or stem fracture (1 hip), and seven were revised because of migration and aseptic loosening of the socket. The cementless ingrowth stems failed earlier (around 5 years), whereas the cemented stems continued to perform well past 14 years. In this study, the cemented, collarless, collarless, porous-coated anatomic design at an average follow-up period of 7 years (range, 2–14 years).     

Mid-term results of Exeter vs Endurance cemented stems

The mid-term results are reported of 2 uniquely different cemented stems implanted and followed prospectively by a single surgeon. The highly polished, collarless, tapered Exeter stem and the Endurance stem, a collared, roughened, satin finished stem, were inserted through a lateral approach using third-generation cement techniques. A total of 118 hips with the Exeter stem with an average follow-up of 7.25 years and 34 hips with the Endurance stem with an average follow-up of 4.57 years are included in the study. The Exeter patients had no revisions for aseptic loosening (0%) of the femoral stem. In contrast, the Endurance patients had 5 revisions and 2 impending revisions for aseptic loosening (20.5%) of the femoral stem with an average time to failure of 3.72 years. The excellent mid-term results of the Exeter stem support its ongoing use. By contrast, because of the poor early results of this modern cemented Endurance stem design, it is no longer used at our institution.     

Cemented total hip arthroplasty: still relevant in the new millennium?

Total hip arthroplasty can be performed successfully using cement or cementless technology. Cemented femoral stems can achieve enduring long-term suvivorship as long as meticulous surgical technique is utilized and patient selection is appropriate. Cemented acetabular components should only be utilized in patients with less than 10 years of remaining life expectancy. Critical risk factors for cemented total hip arthroplasty include atrophic osteoarthrtis on the acetabular side and unfavorable femoral geometry for the femoral stem such as "the stove-pipe" canal. Rapid polyethylene wear and osteolysis are rarely seen in contemporary cemented total hip arthroplasty performed with a smooth, tapered, collarless femoral stem with a highly polished head and a well-designed acetabular component.     

Cemented primary total hip arthroplasty using a direct anterior approach

Total hip arthroplasty is one of the most successful surgeries used in medicine today. A major complication associated with significant comorbidity for THA is periprosthetic fracture. A number of risk factors associated with periprosthetic fracture have been identified, including the use of uncemented femoral fixation. In patients with significant risk factors, we use a collarless, composite beam cemented stem in order to mitigate the risk of periprosthetic fractures. This article describes the surgical technique utilized to obtain a safe and effective cemented fixation through the direct anterior approach of the hip.     

Initial stability of cemented femoral stems as a function of surface finish, collar, and stem size

BACKGROUND: The optimum surface roughness of cemented femoral stems used for total hip replacement is a subject of controversy. While rougher surfaces provide stronger cement adhesion, it has been hypothesized that polished, tapered, noncollared stems settle into the cement mantle, providing improved stability. However, the effects of surface finish on the stability of straight, cemented stems tapered only in the coronal plane are not known. METHODS: Using composite model femora, we assessed the initial stability of a straight, cemented femoral stem as a function of surface roughness, the presence or absence of a collar, stem size, and the resultant cement thickness under simulated walking and stair-climbing loads. Otherwise identical stems were manufactured with polished or rough surfaces, with or without a collar, in two different sizes. We isolated these three variables and compared their relative contributions to the motion at the stem-cement interface throughout cyclic loading. We defined three indicators of stability: per-cycle motion, rate of migration, and final migration. RESULTS: Surface roughness had a greater influence on per-cycle motions than did the presence or absence of a collar or cement thickness. Specifically, in the medial-lateral direction, per-cycle motion of polished stems was 43 micro m greater than that of rough stems (p < 0.01). None of the per-cycle motions decreased over the 77,000 load cycles. In contrast, with all stems, the rate of migration decreased over the course of cyclic loading, but the rate of migration of the polished stems was greater than that of the rough stems. Final migrations of the stems over the course of loading were generally distal, medial, and into retroversion. Compared with rough stems, polished stems had 8 to 18 micro m more axial migration (p < 0.001), 48 micro m more anterior-posterior migration (p < 0.001), and 0.4 degrees more rotational migration (p = 0.01). CONCLUSIONS: and Clinical Relevance: The results indicated that, for cemented, straight femoral stems tapered only in the coronal plane, a rough surface offers the advantage of less per-cycle motion. These results may apply to widely used cemented stem designs based on the profile of the original Charnley femoral component, which has approximately parallel anterior and posterior aspects.