Mid-term results of large diameter heads on cross-linked polyethylene liners in total hip replacement

BackgroundHighly cross-linked polyethylene liners in total hip replacement (THR) have allowed the use of larger diameter femoral heads. Larger heads allow for increased range of motion, decreased implant impingement, and protection against dislocation. The purpose of this study is to assess the clinical and radiographic outcomes of patients with large femoral heads THR at 4 years postop.Materials and methodsStudy includes 28 patients who had a primary THR with a 36 mm larger femoral head were retrospectively for minimum 4 years follow-up. All patients received a cementless acetabular shell and a highly cross-linked polyethylene liner with an inner diameter of 36 mm. The median radiographic follow-up was 4 years (range 2.0–6.0), and patients were assessed clinically by Harris hip score.ResultsThe mean follow-up is minimum 4 years (range 2–6 years) results in all operated patients showed marked improvement in Harris hip score from preoperative mean 49.1 to 89.9 at 4 years or more follow-up. The complications include superficial infection (n = 2). No dislocation, or no osteolysis was seen in the pelvis or proximal femur, and no components failed due to aseptic loosening. There was no evidence of cup migration, screw breakage, or eccentric wear on the liner.ConclusionThe mid-term results in this series of patients with LDH using 36 mm femoral head articulating with highly cross linked polyethylene showed excellent clinical, and radiological results, in terms of, joint restoration that replicates the natural anatomy, optimized range of motion without impingement & reduced opportunity for postoperative dislocation.     

Total hip arthroplasty using an Omniflex modular system: 5 to 12 years followup

We evaluated intermediate-term results of primary cementless Omniflex prostheses. Forty-nine patients (57 hips) with a mean age of 44 years were observed for an average of 8.6 years. The average Harris hip score was 46 points before surgery and 87 points at final followup. Revision was done in five hips (9%) in five patients. Two acetabular components (4%) were revised because of breakage of the polyethylene insert. Three femoral components (5%) were revised because of aseptic loosening. Six femoral components (10%) were radiographically loose. Overall, 11 hips (19%) were considered mechanical failures. Osteolysis was identified around three acetabular components (5%) and around 20 femoral components (35%). Nine hips (16%) had femoral osteolysis around the distal stem tip. The average annual polyethylene liner wear was 0.18 mm. These results were inferior to those using other recent cementless total hip systems.     

Clinical performance of a Durasul highly cross-linked polyethylene acetabular liner for total hip arthroplasty at five years

BACKGROUND: Highly cross-linked polyethylene is currently the most common articulation surface used for total hip arthroplasty. The hypothesis of the present study was that the Durasul highly cross-linked polyethylene acetabular liner would have less wear at five years than would a conventional polyethylene liner used in association with the same total hip replacement system. METHODS: Forty-three consecutive patients (fifty hips) underwent total hip replacement with an uncemented titanium porous-coated metal cup and a Durasul liner that was mated with a 28-mm cobalt-chromium femoral head. Thirty-one patients (thirty-seven hips) were followed for at least five years. Thirty-five other patients (thirty-seven hips) underwent total hip arthroplasty with the same system but with a conventional polyethylene liner, and these patients also were followed for five years. Clinical assessment was performed with use of the Harris hip score and a patient self-assessment examination. Radiographic analysis included measurements of acetabular component position, fixation, and osteolysis. Femoral head penetration of the Durasul liners was compared with that of the conventional liners. RESULTS: The clinical results as determined on the basis of Harris hip scores and patient self-assessment examinations did not differ between the Durasul group and the control group. The mean bedding-in penetration was 0.054 +/- 0.07 mm for the Durasul group and 0.059 +/- 0.154 mm for the control group. The subsequent penetration, with elimination of the bedding-in wear, resulted in a linear wear rate of 0.029 +/- 0.02 mm per year for the Durasul group, compared with 0.065 +/- 0.03 mm per year for the control group (p < 0.005). The annual penetration at one and five years was 0.074 mm and 0.011 mm, respectively, for the Durasul group, compared with 0.151 mm and 0.04 mm, respectively, for the control group. CONCLUSIONS: While the qualitative wear pattern of the highly cross-linked polyethylene liner was the same as that of the conventional polyethylene liner, the annual linear wear rate was 45% of that seen with the conventional polyethylene liner. Therefore, we believe that these early data support the continued use of this highly cross-linked polyethylene liner for total hip arthroplasty.     

Intermediate results of simultaneous alumina-on-alumina bearing and alumina-on-highly cross-linked polyethylene bearing total hip arthroplasties

This study compared the clinical and radiographic results and the prevalence of osteolysis between alumina-on-alumina and alumina-on-highly cross-linked polyethylene bearings after cementless total hip arthroplasties in the 100 patients younger than 50 years of age. There were 66 men and 34 women; the mean age at the time of surgery was 45.3 years (range, 25 to 49 years). The mean duration of follow-up was 5.6 years (range, five to seven years). The pre-and postoperative Harris hip scores were similar (39 and 41 points, respectively and 93 points and 94 points, respectively). No acetabular or femoral component had aseptic loosening in either group. The mean annual penetration of the highly cross-linked polyethylene was 0.06 ± 0.03 mm. No hip in either group had acetabular or femoral osteolysis.     

Tapered titanium cementless total hip replacements: a 10- to 13-year followup study.

The 10- to-13 year performance of 307 Mallory Head cementless tapered total hip replacements in 283 patients was assessed. Eighty-five percent of patients had a diagnosis of osteoarthritis. Fifty-one percent of patients were women. The mean patient age was 64 +/- 10 years. The Hex Loc cementless acetabular component and titanium alloy femoral heads were used in each patient. At final followup, 37 (13%) patients died, 32 (10%) had revision surgery, and two (1%) were lost to followup. No femoral stem was revised for aseptic loosening, but one was revised because of sepsis and one was revised because of a periprosthetic fracture. Wear, osteolysis, and loosening were problems with the Hex Loc cementless acetabular components and 31 (10%) acetabular components required revision because of these mechanisms. The mean Harris hip score at final followup of the remaining patients was 87 +/- 14 points. Three percent of these patients had thigh pain. Radiographic assessment revealed that no femoral stem or acetabular socket was definitely or probably loose. Three-dimensional wear assessment using the Devane technique was 0.35 mm per year. The Mallory Head cementless, tapered femoral component performed well in the patients in the current study, but unfortunately, the clinical results were compromised by the use of a suboptimal cementless acetabular component, the use of polyethylene that was gamma-irradiated in air, and by the use of titanium alloy femoral heads. Future developments obviously will be in the areas of better acetabular component design, alternate polyethylene sterilization methods, and enhancements of the femoral stem in terms of offset choices, neck design, and perhaps ingrowth surface.     

Single-stage Acetabular Revision During Two-stage THA Revision for Infection is Effective in Selected Patients

Background

The treatment of periprosthetic infections of hip arthroplasties typically involves use of either a single- or two-stage (with implantation of a temporary spacer) revision surgery. In patients with severe acetabular bone deficiencies, either already present or after component removal, spacers cannot be safely implanted. In such hips where it is impossible to use spacers and yet a two-stage revision of the prosthetic stem is recommended, we have combined a two-stage revision of the stem with a single revision of the cup. To our knowledge, this approach has not been reported before.

Questions/purposes

(1) What proportion of patients treated with single-stage acetabular reconstruction as part of a two-stage revision for an infected THA remain free from infection at 2 or more years? (2) What are the Harris hip scores after the first stage and at 2 years or more after the definitive reimplantation?

Methods

Between June 2009 and June 2014, we treated all patients undergoing surgical treatment for an infected THA using a single-stage acetabular revision as part of a two-stage THA exchange if the acetabular defect classification was Paprosky Types 2B, 2C, 3A, 3B, or pelvic discontinuity and a two-stage procedure was preferred for the femur. The procedure included removal of all components, joint débridement, definitive acetabular reconstruction (with a cage to bridge the defect, and a cemented socket), and a temporary cemented femoral component at the first stage; the second stage consisted of repeat joint and femoral débridement and exchange of the femoral component to a cementless device. During the period noted, 35 patients met those definitions and were treated with this approach. No patients were lost to followup before 2 years; mean followup was 42 months (range, 24–84 months). The clinical evaluation was performed with the Harris hip scores and resolution of infection was assessed by the absence of clinical signs of infection and a C-reactive protein level less than 10 mg/L. All patients were assessed before surgery, between stages, every 3 months during the first year after surgery, every 6 months during the second year postoperative, and at latest followup, and were retrospectively drawn from a longitudinally maintained institutional database.

Results

Thirty-four of 35 patients (97.2%; 95% CI, 85.4%-99.5%) appeared free of infection by criteria of Masri et al. and Zimmerli et al. at latest followup. The Harris hip score was 61 ± 13 points after the first operation and 82 ± 16 points 2 years after the second operation.

Conclusions

This technique is a promising treatment option for periprosthetic infections of the hip in which substantial acetabular defects exclude implantation of a normal spacer and a two-stage revision of the femoral component is favored.

Level of Evidence

Level IV, therapeutic study.

     

Mid-term results using a cementless hip prosthesis in young Chinese patients: a five- to seven-year follow-up study

A retrospective study was undertaken to evaluate the clinical and radiographic outcomes of 74 cementless total hip arthroplasties (THA) in 69 young Chinese patients. The Asian size and MMA AML stems with smoothly tapered tip were used, and the patients were followed up for at least five years. The mean Harris hip score was 45.4 preoperatively and 95.3 at the last follow-up. The incidence of thigh pain was 5.4%, and was related to the short stature of the patient (<160 cm) (P = 0.030). Six patients (6 hips, 8.1%) had acetabular osteolysis in zone 2; reoperation was performed in one patient because of osteolysis and wear of the polyethylene liner. The survival rate of the metal acetabular and femoral components was 100% (95% confidence interval, 0.95–1.0). Primary THA with this AML prosthesis had an acceptable mid-term result in young Chinese patients.     

Ten- to Sixteen-Year Follow-Up of Highly Cross-Linked Polyethylene in Total Hip Arthroplasty: What Factors Affect Wear?

BackgroundIncrease in acetabular cup abduction in total hip arthroplasty (THA) using conventional polyethylene is associated with greater linear wear. Whether this relationship holds true for highly crosslinked liners, particularly with long-term follow-up, is still controversial. The effect of liner thickness on wear of highly cross-linked liners also remains to be clarified.This study sought to determine (1) the long-term clinical and radiological performance of highly cross-linked polyethylene in THA and (2) the effect of acetabular component positioning, polyethylene thickness, and patient demographics on wear.MethodsNinety-three THAs using a 28-mm hip ball, single brand of highly cross-linked polyethylene liner, and cementless cup were performed in 87 patients. Clinical outcomes were evaluated using the Harris Hip Score and need for revision surgery. Linear and volumetric wear, presence of osteolysis, and cup abduction angle were assessed.ResultsThe mean age at operation was 51.4 years. The mean duration of follow-up was 12.7 years (10-16 years). Patients aged >50 years had higher rates of linear wear than those aged <50 years (P = .015). Positive correlation was found between cup abduction angle (P = .014) and cup version (P = .035) with a linear wear rate. Thinner liners (≤7 mm) had similar rates of linear and volumetric wear as thicker liners (≥8 mm) (P = .447).ConclusionThis is the only study to demonstrate a positive significant relationship between cup abduction angle and version with linear wear rate in THA with at least 10 years of follow-up. Liner thickness was not found to affect wear rates.