Clinical and radiographic analysis of the uncemented LSF total hip arthroplasty

High Subsidence Rate After Primary Total Hip Arthroplasty Using a Zweymüller-type Noncemented Implant With a Matte Surface

Introduction:

The surface topography is one key factor that affects the initial fixation of prosthesis in total hip arthroplasty (THA). We aimed to evaluate the mid-term results of a Zweymüller-type noncemented femoral implant (Elance stem) that had a matte surface with a target average roughness of 1.0 to 2.5 μm. The prosthesis was subjected to alkali and heat treatments to enhance its bone-bonding property.

Methods:

In this retrospective study, 30 THAs (27 patients) done using an Elance stem from September 2012 to October 2014 were evaluated clinically and radiographically for a mean follow-up of 6.3 ± 1.7 years after the index THA.

Results:

Stem revision was indicated for six hips (20%). The survival rate with stem revision for any reason was 86.4% (95% confidence interval, 68.9%-94.8%) at 5 years. Stem subsidence >5 mm was noted in 17 hips (56.7%). The survival rate with stem subsidence >5 mm as the end point was 46.6% (95% confidence interval, 29.9%-64.2%) at 5 years.

Conclusion:

The Zweymüller-type noncemented stem with a low-roughness matte surface demonstrated a high subsidence rate, although the bone-bonding property was potentially enhanced by the alkali and heat treatments. Surgeons should be aware that an insufficient surface roughness could lead to poor mechanical fixation of the noncemented stem, even with an appropriate stem geometry and surface chemistry.

Incidence and Location of Pain in Young, Active Patients Following Hip Arthroplasty

Persistent pain following hip arthroplasty remains a concern, especially in young, active patients. Four hundred twenty patients less than 60 years of age with a pre-symptomatic UCLA score ≥ 6 (196 total hip arthroplasty [THA]; 224 surface replacement arthroplasty [SRA]) completed a pain-drawing questionnaire investigating the location, severity, and frequency of pain around the hip. At a mean of 2.9 years of follow-up, 40% reported pain in at least one location around the hip. There was no difference in the incidence of groin pain between SRA and THA patients (32% vs. 29%, P=0.6), but THA patients had a greater incidence of anterior (25% vs. 8%, P<0.001) and lateral (20% vs. 10%, P=0.01) thigh pain. A high percentage of young, active patients experience persistent pain following hip arthroplasty.

Analysis of retrieved uncemented porous-coated acetabular components in patients with and without pelvic osteolysis

Retrieved polyethylene liners and femoral heads from a consecutive series of revision components of one design were examined. All patients had Long-Term Stable Fixation (OsteoTechnology International, Timonium, Md) total hip arthroplasties (THAs) implanted between 1987 and 1992. The retrieved femoral heads and liners from patients with osteolysis were compared to those without osteolysis. Patients with osteolysis had significantly thinner polyethylene (5.1 mm versus 7.4 mm, P<.01 ) and a higher linear wear rate (0.5 mm/y versus 0.3 mm/y, P=.05). The average femoral head surface roughness also was significantly greater in patients with osteolysis (67 nm versus 35 nm, P<.05). Patients with osteolysis had more total volumetric wear, total linear wear, and volumetric wear rate compared to patients without osteolysis. Age, obesity index, time in situ, and cup inclination were not different between the two groups. Excessive polyethylene wear, probably accelerated by surface roughness of the femoral heads, was associated with pelvic osteolysis in these patients.

Patients' perception of pain after total hip arthroplasty

A study was undertaken to determine the frequency with which patients had pain that they attributed to their hip after total hip arthroplasty. Pain drawings were used to allow patients to localize the area of their symptoms, and the degree of pain was quantified with visual analog scales. Complete clinical and radiographic data were collected on all patients so that the occurrence of pain could be correlated with a number of parameters previously reported to affect the incidence of pain, including age, sex, activity level, length of follow-up, stem size, bone type (Dorr index), and type of stem fixation (proximally coated, fully coated, or cemented). Results indicated that type of stem fixation was the only parameter statistically correlated with a higher incidence of thigh pain. Patients with proximally coated stems were more than twice as likely to complain of pain than patients with fully coated or cemented hips (P < .01). Although the incidence of thigh pain was significantly higher with proximally coated stems, the severity was not, averaging 3.0 to 3.5 out of 10 on visual analog scale in all 3 groups. The results indicate that patients perceived pain as originating in the hip in a high percentage of cases, particularly when proximally coated stems were used.

Clinical and radiographic outcomes of total hip arthroplasty with insertion of an anatomically designed femoral component without cement for the treatment of primary osteoarthritis. A study with a minimum of six years of follow-up

We evaluated the clinical and radiographic outcomes of 100 consecutive primary total hip arthroplasties in which a proximally coated anatomically designed femoral component was fixed without cement for the treatment of primary osteoarthritis. The minimum duration of follow-up was six years (average, 7.1 years). The eighty-eight patients who had the arthroplasties were followed prospectively with a standard clinical evaluation that involved use of the Harris hip score and a radiographic evaluation based on the criteria of the Hip Society. Bone ingrowth was evaluated with the method of Engh et al. The average age of the patients at the time of the operation was 62.6 years (range, thirty-nine to eighty-four years). Fifty-one patients were men and thirty-seven were women. The average preoperative Harris hip score was 48 points, with an average pain score of 15 points and an average function score of 26 points. Nonmechanical complications that necessitated a revision operation included one deep hematogenous infection, one late periprosthetic fracture, and a 0.5-inch (1.27-centimeter) limb-length discrepancy. At the time of the most recent follow-up, the average Harris hip score was 96 points, with an average pain score of 42 points and an average function score of 45 points. The prevalence of pain in the anterior part of the thigh was 5 percent (five hips). One patient had a revision of the femoral component because of aseptic loosening, and one had a revision of the acetabular component because of recurrent dislocations. Radiographic assessment revealed consistent evidence of proximal bone ingrowth. No complete radiolucent line was identified, except around the stem that had loosened. Twenty-seven femoral components were associated with slight pedestal formation. No osteolytic lesion of the femur was identified. Nonprogressive pelvic osteolysis was identified in four hips, but none of the lesions were more than two millimeters in diameter. None of the acetabular components migrated, and no radiolucent line of more than two millimeters in thickness was seen around any acetabular cup. The data from this study, in which the minimum duration of follow-up was six years, indicate that the anatomically designed prosthesis can provide good results, with low prevalences of pain in the thigh and loosening of the component, in younger, active patients.

Outcome of total hip replacement in Japan and England. Comparison of two retrospective cohorts

Two retrospective cohorts of patients who had undergone a primary total hip replacement (THR) were studied in Japan and England. We analyzed information from hospital case notes and self-administered questionnaires. THR was highly effective in both countries, with significant improvements in morbidity and health status. There were, however, important differences in clinical management and outcome. Japanese patients were more likely to be treated under regional anesthesia by means of an anterior/anterolateral incision, to be transfused, to have a prosthesis implanted without cement, and to stay longer in the hospital. A higher rate of serious in-hospital complications occurred in England, mostly due to the high frequency of hypotension. The incidences of minor complications were consistent with known differences in risks between the two countries. The persistent postoperative perception of limping reported by the English patients was unexpected.

Five-year clinical and radiographic follow-up of the uncemented long-term stable fixation total hip arthroplasty

Thirty-nine uncemented porous-coated long-term stable fixation total hip prostheses with a minimum 5-year follow-up, were retrospectively reviewed for clinical and radiographic outcome. Clinical evaluation was performed using the modified Harris Hip Score. Additionally, all patients completed a satisfaction questionnaire. Anteroposterior view and lateral view radiographs were obtained and compared with immediate postoperative films utilizing the Hip Society radiographic evaluation form for uncemented implants. The follow-up period averaged 69 months (range, 60-87 months). At the most recent follow-up visit Harris Hip Scores averaged 88 points (range, 68-100 points), with 79% good or excellent results. Of the 8 hips (6 patients) with fair or poor results, 5 patients (6 hips) were Charnley category C patients. All patients were satisfied with their surgery and all, but 2 stated that their function had significantly improved. The incidence of significant thigh pain was 13%. Calcar osteolysis was present in 13 of 39 femurs with the majority of cases being minimal. All but one femoral component demonstrated bone ingrowth. There was no distal femoral osteolysis present and no femoral revisions have been performed or are planned. Acetabular osteolysis was present in 7 of 39 hips, with 4 of the 7 centered around acetabular fixation screws. All patients who had acetabular bone loss had some degree of femoral osteolysis. Thus far, one patient has required acetabular revision secondary to osteolysis. Acetabular osteolysis in this series was more profound than on the femoral side and two other patients are being considered for revision due to pelvic side osteolysis. In conclusion, the uncemented long-term stable fixation femoral component proved to be durable in this series of patients. The circumferential porous coating on the femoral implant may protect against distal osteolysis. A concerning rate of severe pelvic osteolysis and impending failure was noted and may lead to a greater need for revision surgery with longer follow-up.

Acetabular screw rings and surface treatment

The Zweymüller truncated self tapered threaded ring is forged in pure titanium with a 3- to 5-mu grit blasted surface roughness. Among 167 consecutive primary total hip arthroplasties prospectively studied, two threaded components failed to achieve initial stability, with one requiring almost immediate revision. One hundred twenty-six hips have been fully documented with a 5-year minimum followup. The mean modified Harris hip score improved from 44.4 points preoperatively to 91 points at 7 years average followup (range, 60-121 months). Bone to implant gap rate decreased from 54.7% after surgery to 2.4% at last review, with only one detectable early migration that had secondary stable osseointegration. Annual linear wear of more than 0.2 mm per year could be detected in only one ceramic on polyethylene bearing surface with one corresponding femoral osteolysis granuloma. At the 9- to 10-year interval, the survivorship with definite loosening as a failure was 98.7%. Delayed loosening by failure of an initially stable reconstruction, progressive lucencies, liner disassociation, or worrisome osteolysis have not been observed. These midterm results are much better than those of former screw rings with smooth surface finishes. The main reason for the general failure and justified abandonment of threaded polished components may not be the screw in mechanism of their primary fixation, but the lack of an appropriate surface for bone ingrowth and osseointegration.

Patients' expectations and satisfaction with total hip arthroplasty

Although there have been many studies focusing on the increasingly important assessment of patients' satisfaction, few studies have specifically addressed this tissue for total hip arthroplasty (THA). The goals of this study were to measure patients' satisfaction with THA and to evaluate the relationships of expectations and outcome to patients' satisfaction. A total of 180 patients were surveyed 2 to 3 years after THA about their experiences with THA. Patients cited 45 different expectations, which were grouped into five categories reflecting improvement in pain, walking, psychological state, essential activities, and nonessential activities. Overall, 89% of patients were satisfied with the results of surgery. Lower rates of satisfaction were found in patients who had a better preoperative condition (as measured by the surgeons with The Hospital for Special Surgery Hip Scale), in patients who expected improvement in nonessential activities, and in patients who reported worse postoperative condition (as measured by self-assessment with the Hip Rating Questionnaire and the Medical Outcomes Study Short-form General Health Survey). Patients were also asked how they came to THA. Nearly 50% of patients were first referred to an orthopaedist by family or friends or based on their own knowledge. Seventy-four percent either had subsequently referred others for THA or would have done so if they knew someone with hip pain. This study demonstrates that satisfaction with THA is a complex phenomenon, affected by expectations, outcome, and what patients know about the procedure from their community network. A better understanding of THA satisfaction will enable better future selection of patients and an additional dimension of outcome, both of which are important to patients and payers.