Uncemented Total Hip Arthroplasty in Patients Younger Than 50 Years: A 6- to 10-Year Follow-up Study

Posted on April 10, 2010

by Tian J. Liang, PhD; Mu Z. You, PhD; Pei F. Xing, MD; Shen Bin, MD; Zhou Zhong Ke, PhD; Yang Jing, MD

Abstract

Young patients are expected to place increased demands on total hip arthroplasty (THA) because they are more active and have a longer life expectancy. The long-term outcome of the Charnley low-friction arthroplasty in young, active patients has been shown to be associated with a high degree of polyethylene wear and osteolysis. However, cementless acetabular components have been shown to be successful in young patients.

We evaluated the clinical and radiographic results of 77 cementless THAs in 81 young, active patients at a mean follow-up of 7.5 years. Mean preoperative Harris Hip Score improved from 46.24 to 96.5 points at 6 years. One acetabular component showed aseptic loosening 10 years postoperatively. Three patients (3 hips) underwent bone grafts and liner renewal for severe osteolysis around the acetabular component. The rate of survival at 6 years for loosening was 98.8%, and for revision of the liner was 95.5% (95% confidence interval, 93%-98%). Mean liner wear rate was 0.125 mm/year (range, 0.0-0.39 mm/year). Acetabular osteolysis was found in 14% (9 hips) of the 67 hips and was related to polyethylene wear (P=.0024). Although there was only 1 cup loosening in this study, there was a high rate of linear wear of the polyethylene liner and acetabular osteolysis in young, active patients. Further follow-up is therefore needed, and osteolysis and polyethylene wear should continue to be observed in young, active patients.

Young patients are expected to place increased demands on total hip arthroplasty (THA) because they are more active and have a longer life expectancy. Therefore, it is important to apply a more conservative approach with these patients. Generally, it is recommended that nonoperative treatment modalities be exhausted before a THA is considered for patients younger than 50 years. Other surgical treatment options, including osteotomy, fusion, or cup arthroplasty, may be considered to avoid a THA. When a THA is considered for a patient in this age group, determining what type of THA is best can be confusing to a surgeon. The long-term outcome of the Charnley low-friction arthroplasty in young, active patients has been shown to be associated with a high degree of polyethylene wear and osteolysis.1-3 However, cementless acetabular components have been shown to be successful in young patients. We reviewed the mid-term results of uncemented THA in patients younger than 50 years of age at our institution with a 6- to 10-year follow-up.

Materials and Methods

Between January 1998 and September 2002, 106 primary uncemented THAs were performed in 101 consecutive patients aged 50 years or younger at our institution. One patient died 5 years postoperatively from unrelated causes. Twelve patients moved away and were lost to follow-up. Eleven patients ceased returning for follow-up after 3 years because they were asymptomatic. No evidence of loosening was apparent radiographically at last follow-up in this group.

The remaining 77 patients (54 men, 23 women) underwent a total of 81 THAs. Average patient age was 37.42 years (range, 21-50 years) at the time of the initial THA. Twenty-four patients (26 hips) were aged 21 to 30 years, 31 patients (32 hips) were aged 31 to 40 years, and 22 patients (23 hips) were aged 41 to 50 years. Average weight and height were 65.18 kg and 166.94 cm, respectively. Follow-up averaged 7.5 years (range, 6-10 years).

The preoperative diagnoses are shown in the Table. Two types of acetabular cups and 2 types of femoral stems were used. Twenty-six hips had a Vitalock Cluster Shell cup (Stryker Howmedica, Warsaw, Indiana) and 55 had a Duraloc 300 Series cup (DePuy, Warsaw, Indiana). Fifty-five hips had an AML femoral stem (DePuy), and 26 hips had a CORAIL femoral stem (DePuy). Ten patients (10 hips) had undergone previous surgery because of related fracture. A 28-mm chrome-cobalt femoral head was used in all patients.

Perioperative management was similar for all patients. All procedures were performed in a vertical laminar air-flow operating room. All patients received preoperative intravenous antibiotic therapy, which was continued for 24 hours. Warfarin was used on all patients for deep vein thrombosis prophylaxis. Quadriceps, gluteal, and hamstring setting exercises were started on the first postoperative day. Patients were mobilized on the second postoperative day with a regimen of touch-down weight bearing for 6 weeks, followed by progressive weight bearing over the subsequent 6 weeks. All patients were continued on bilateral walking aids for a minimum of 12 weeks.

Three orthopedic surgeons (P.F.X., Y.J., S.B.) performed all the hip replacements. All patients had general anesthesia. The surgical approach was posterolateral in all hips. The acetabulum was reamed to the same diameter as the Vitalock Cluster Shell, whereas a shell 2 mm greater than the diameter of the final reamer was used for the Duraloc 300 Series. All acetabular components were 28-mm inner-diameter made of conventional 415 GUR polyethylene (Hoechst Celanese, Houston, Texas), which was gamma-irradiated and ram-extruded. The femoral head size was 28 mm in all hips.

Clinical and radiographic data were collected on standardized hip evaluation forms preoperatively, at 6 months, and at yearly follow-up. The radiographs were digitized. The clinical assessment included an evaluation of pain as well as of functional parameters such as walking, stair-climbing, use of external support, limp, and ability to perform daily activities involving the hip. A composite Harris Hip Score was calculated on the basis of these data.4

Migration, lucent lines, abduction angle, heterotopic ossification, osteolysis, and wear of polyethylene were assessed on radiographs with Canvas 6.0 (ACD Systems, Victoria, British Columbia, Canada). Radiolucent lines were evaluated in the 3 acetabular zones and 14 femoral zones described by DeLee and Charnley.5 Osteolysis was defined as a circular or oval area of distinct bone loss. Evidence of migration was measured on follow-up radiographs. The acetabular component was considered loose if there was 2 mm of migration from either the inter-teardrop or vertical lines, or a change of 4° in the abduction angle. Looseness of the femoral component was judged by the methods of Kim and Kim.6,7 Heterotopic ossification was measured with the method of Brooker et al.8

Liner polyethylene wear was measured using a digital hip analysis suite.9,10 In accordance with Duffy et al,11 osteolysis was graded as mild (>1 cm2), moderate (1-1.9 cm2), or severe (>2 cm2) on anteroposterior (AP) radiographs of the pelvis and monitor-guided AP radiographs of the cups.

Five measurements were taken for each patient and a mean value was calculated. The analysis was performed on digitized radiographs. The underlying approach of the computer-assisted vector analysis of wear was to find the circles that best fit the prosthetic femoral head and the acetabular component. The magnitude and direction of the displacement of the femoral head vector from the acetabular center were calculated on final follow-up radiographs. If the polyethylene liner required exchange, measurements were made on the radiograph taken immediately before this revision.

Statistics

The endpoint for survival was defined as revision or loosening in radiographs. Aseptic loosening was considered as a separate endpoint, because “revision for any reason” included nonimplant-related operations. Kaplan-Meier survival data were used to construct the survival probabilities of implants at 5 years.

Results

Clinical Results

The overall clinical result was satisfactory, with a mean preoperative Harris Hip Score of 45.32 points (range, 5-76 points) and a mean postoperative score of 94.5 points (range, 67-100 points) at final follow-up. There was no pain in 71 hips (71 patients). When the patients with pain were questioned about location, only 1 (slight pain, no medication taken) stated it was thigh pain, and the others stated it was in the hip (4) and buttock (1).

Preoperatively, 6 patients (8%) used no support for walking, 25 (32%) used a cane, 21 (28%) used a crutch, and 25 (32%) used 2 crutches. At final follow-up, no patient used a support. Preoperatively, every patient had a limp; 28 (36%) had a mild limp, 25 (33%) had a moderate limp, and 24 (31%) patients had a severe limp. At final follow-up, 72 (93%) patients had no detectable limp, 3 patients with ankylosing spondylitis had a mild limp caused by a stiff spine, 1 patient with a severe rheumatoid arthritis had a moderate limp, and 1 patient with acetabular loosening had a moderate limp. The ability to use stairs and public transportation and to put on footwear and cut toenails were markedly improved postoperatively.

Radiological Analysis

Acetabular Component. Of the 81 implanted acetabular components, 76 (93%) were considered to be stable based on comprehensive osseointegration after a minimum period of 6 years. One showed a continuous radiolucency with migration, which led to revision (Figure 1).

Radiolucent lines around the component were observed in DeLee and Charnley zone I in 3 radiographs, zone II in 5, and zone III in 4.

Eight hips with the Duraloc cup had osteolysis around the cups. Four hips had severe osteolysis, 3 had moderate osteolysis, and 4 had mild osteolysis. One Vitalock cup had a >4° change in acetabular abduction after 5 years. The mean rate of liner wear was 0.124 mm/year (range, 0.0-0.39 mm/year), and mean volumetric wear was 0.104 cm3/year (range, 0.0-0.313 cm3/year).The liner and volumetric wear have no relationship to sex, weight, or height. Acetabular heterotopic ossification was seen in 12 hips (14.8%): 6 were Brooker grade 1, five were grade 2, and 1 was grade 3 (Figure 2).

Femoral Component. No femoral component loosening was evident on radiographs. Femoral cortical hypertrophy occurred in distal medial zone 5 in 32 hips (39.5%) and in lateral zone 3 in 18 (18.8%). Thickening of the inner cortex around the tip of the stem (zone 4) was observed in 10 hips (12.3%). A complete pedestal was observed in 2 hips. Huge osteolysis was found in the greater trochanter in 1 hip (Figure 3).

Survival of the Component. Aseptic loosening was evident radiographically in 1 acetabular component 10 years postoperatively. Three patients (3 hips) underwent bone graft and liner renewal for severe osteolysis around the acetabular component. The rate of survival at 6 years for loosening was 98.8% and for revision of the liner was 95.5% (95% confidence interval, 93%-98%). Liner and volumetric wear among revised patients were measured individually: 0.252 mm/year and 202.567 mm3/year; 0.212 mm/year and 170.414 mm3/year; and 0.390 mm/year and 313.497 mm3/year, respectively.

Discussion

In earlier studies, high rates of failure were observed in cemented THA in young patients. In most of these studies, the rates of failure were >35%, which may be due to the immature cemented technology.12-15 The uncemented prosthesis was developed for young patients with good bone block. Few reports in the literature examine uncemented prostheses in young patients. Our study shows that the uncemented prosthesis had satisfactory results in THA in young patients with 6- to 10-year follow-up. Only 1 cup was revised for loosening.

The mean rate of liner wear was 0.124 mm/year (range, 0.0-0.39 mm/year), and osteolysis was observed in 11.11% of the surviving patients in our study. Severe polyethylene wear in metal-backed cementless acetabular cups has been shown to be associated with early clinical failure. In a consecutive series of patients aged 50 years or younger using the Mallory-Head plasma-sprayed prosthesis (Biomet, Warsaw, Indiana), Dowdy et a1,16 reported a 29% incidence of significant acetabular osteolysis with 5 of 41 cups definitely loose at an average of 5.3 years. Our study shows that osteolysis was related with liner wear. High rates of liner wear and osteolysis are the main causes of failure for young patients with uncemented prostheses.

References

  1. Callaghan JJ, Forest EE, Sporer SM, Goetz DD, Johnston RC. Total hip arthroplasty in the young adult. Clin Orthop Relat Res. 1997; (344):257-262.
  2. Hartofilakidis G, Karachalios T, Zacharakis N. Charnley low friction arthroplasty in young patients with osteoarthritis. A 12- to 24-year clinical and radiographic followup study of 84 cases. Clin Orthop Relat Res. 1997; (341):51-54.
  3. Joshi AB, Porter ML, Trail IA, Hunt LP, Murphy JC, Hardinge K. Long-term results of Charnley low-friction arthroplasty in young patients. J Bone Joint Surg Br. 1993; 75(4):616-623.
  4. Harris WH. Traumatic arthritis of the hip after dislocation and acetabular fractures: treatment by mold arthroplasty. An end-result study using a new method of result evaluation. J Bone Joint Surg Am. 1969; 51(4):737-755.
  5. DeLee JG, Charnley J. Radiological demarcation of cemented sockets in total hip replacement. Clin Orthop Relat Res. 1976; (121):20-32.
  6. Kim YH, Kim VE. Results of the Harris-Galante cementless hip prosthesis. J Bone Joint Surg Br. 1992; 74(1):83-87.
  7. Kim YH, Kim VE. Uncemented porous-coated anatomic total hip replacement. Results at six years in a consecutive series. J Bone Joint Surg Br. 1993; 75(1):6-13.
  8. Brooker AF, Bowerman JW, Robinson RA, Riley LH Jr. Ectopic ossification following total hip replacement. Incidence and a method of classification. J Bone Joint Surg Am. 1973; 55(8):1629-1632.
  9. Hui AJ, McCalden RW, Martell JM, MacDonald SJ, Bourne RB, Rorabeck CH. Validation of two and three-dimensional radiographic techniques for measuring polyethylene wear after total hip arthroplasty. J Bone Joint Surg Am. 2003; 85(3):505-511.
  10. Martell JM, Berdia S. Determination of polyethylene wear in total hip replacements with use of digital radiographs. J Bone Joint Surg Am. 1997; 79(11):1635-1641.
  11. Duffy GP, Prpa B, Rowland CM, Berry DJ. Primary uncemented Harris-Galante acetabular components in patients 50 years old or younger: results at 10 to 12 years. Clin Orthop Relat Res. 2004; (427):157-161.
  12. Chandler HP, Reineck FT, Wixson RL, McCarthy JC. Total hip replacement in patients younger than thirty years old. A five-year follow-up study. J Bone Joint Surg Am. 1981; 63(9):1426-1434.
  13. Collis DK. Cemented total hip replacement in patients who are less than fifty years old. J Bone Joint Surg Am. 1984; 66(3):353-359.
  14. Collis DK. Long-term (twelve to eighteen-year) follow-up of cemented total hip replacements in patients who were less than fifty years old. A follow-up note. J Bone Joint Surg Am. 1991; 73(4):593-597.
  15. Dorr LD, Luckett M, Conaty JP. Total hip arthroplasties in patients younger than 45 years. A nine- to ten-year follow-up study. Clin Orthop Relat Res. 1990; (260):215-219.
  16. Dowdy PA, Rorabeck CH, Bourne RB. Uncemented total hip arthroplasty in patients 50 years of age or younger. J Arthroplasty. 1997;12(8):853-862.

Authors

Drs Liang, You, Xing, Bin, Ke, and Jing are from China West Hospital, Chengdu, China.

Drs Liang, You, Xing, Bin, Ke, and Jing have no relevant financial relationships to disclose.

Correspondence should be addressed to: Pei F. Xing, China West Hospital, No. 37, Guoxue Alley, Chengdu, Sichuan Province, China 610041 (peifuxing@163vip.com).

doi: 10.3928/01477447-20100225-18

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