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Polyethylene Liner Exchange of the Harris-Galante Porous I and II Acetabular Components Without Cement
The Journal of Arthroplasty Vol. 21 No. 7 2006
Polyethylene Liner Exchange of the Harris-Galante Porous I and II Acetabular Components Without Cement Results and Complications Paul F. Lachiewicz, MD and Elizabeth S. Soileau, BSN, RN
Abstract: This study reviewed the long-term efficacy of the locking mechanism of the Harris-Galante porous (HGP) I and II acetabular components and the results and complications of polyethylene liner exchange without cement. There were 400 HGP-I components with a mean follow-up of 10 years (range, 2-19 years) and 78 HGP-II components with 8 years of mean follow-up (range, 2-13 years). There has been only 1 liner dislodgement (0.2%). Thirty-five hips (34 patients) have undergone liner exchange without cement. The index acetabular component was implanted as a primary procedure in 19 hips and a revision in 16 hips. No exchanged liner has dislodged at a mean follow-up time of 5.1 years (range, 2-11 years). However, there have been 7 patients (20%) with recurrent dislocation and all required reoperation. Dislocation was significantly lower when an elevated rim liner was used. Key words: polyethylene liner exchange, dislodgement, acetabular component. n 2006 Elsevier Inc. All rights reserved.
were dissatisfied with the 4.5- and 5.1-mm screws, which were somewhat difficult to implant. The Harris-Galante porous II acetabular component (HGP-II) had a shell thickness of 5.6 mm to accommodate the hex head 6.5-mm screws. The polyethylene liner was held in place by 4 or 5 sets of tines (fabricated of commercially pure titanium), based on the size of the component. The results of the HGP-II component are also excellent at 8 to 11 years of follow-up [10]. Dissociation of the polyethylene liner from cementless acetabular components was reported in 28 cases by Louwerse and Heyligers [4]. Of 28 cases with liner dissociation, 13 had a HarrisGalante acetabular component that had been in situ for a mean of 27 months. Della Valle et al [3] reported liner dislodgement in 17 HGP-II and 1 HGP-I acetabular components, which had been in situ for a mean of 7 years. Broken tines were seen in 6 cases, and there were multiple mechanisms of failure including polyethylene wear, fatigue fracture of tines, and fracture of the polyethylene rim.
Polyethylene liner dissociation from cementless acetabular components has been widely reported [1-6]. The Harris-Galante porous I titanium fiber metal-coated acetabular component (HGP-I) has been shown to have excellent bone ingrowth and long-term survival [7-9]. However, the polyethylene liner locking mechanism has been considered bprimitiveQ compared with present-day components. The metal shell thickness of the HGP-I acetabular component was 4.7 mm, and the polyethylene liner was held in place with 3 sets of titanium alloy btinesQ (Fig. 1). Although the early results of this component were very good, surgeons From the Department of Orthopaedics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina. Submitted October 30, 2004; accepted June 25, 2005. No benefits or funds were received in support of the study. Reprint requests: Paul F. Lachiewicz, MD, Department of Orthopaedics, University of North Carolina at Chapel Hill, 3151 Bioinformatics Bldg, CB 7055, Chapel Hill, NC 27599-7055. n 2006 Elsevier Inc. All rights reserved. 0883-5403/06/1906-0004$32.00/0 doi:10.1016/j.arth.2005.06.019
992
Polyethlene Liner Dislodgement in HGP Acetabular Components ! Lachiewicz and Soileau
Fig. 1. Left, HGP-I acetabular component with 3 sets of tines. Right, HGP-II acetabular component with 5 sets of tines.
These authors expressed concern about repeat dislodgement if a new liner was placed into these acetabular shells. They recommended revising a well-fixed shell or cementing a liner into the existing shell. It was also recommended to downsize the modular femoral head to 22 mm to provide for a thicker polyethylene liner. However, there were no data reported on the results or complications of reoperation in these 18 patients. One purpose of the present study was to determine the prevalence of polyethylene liner dislodgement in HGP-I and HGP-II acetabular components implanted by the author. In addition, this study was performed to test the hypothesis that, in the short term, there would be adequate fixation of the polyethylene liner in these acetabular components when revision including liner exchange without cement was performed. The mechanical complications after polyethylene liner exchange were also investigated.
Materials and Methods This is a retrospective study of 429 HGP-I and 87 HGP-II (both Zimmer, Warsaw, Ind) implanted by one surgeon at one hospital. Demographic, clinical, and radiographic data were prospectively stored in the surgeon’s total hip database. Patients (38 hips) had died with less than 2 years of follow-up (identified by ancestry.com), but none had a problem with the total hip arthroplasty. All patients who had a reoperation that included a polyethylene liner exchange without cement were identified. Demographic variables, such as patient age and sex,
993
preoperative diagnosis, and time the shell was in situ were extracted from the database. The operative records, radiographs, follow-up time, and complications after liner exchange were then reviewed. The technique for polyethylene liner exchange involved the posterior approach, with exposure of the entire rim of the acetabular component and checking the integrity of the tines. The tines were bent in slightly using a needle holder and a new polyethylene liner was tapped into place. The polyethylene liner was checked for blever-outQ and rotational stability with a clamp. Repair of the posterior capsule and external rotators was performed in all cases. Postoperatively, the patients were not given any immobilization, except for one patient who was placed into a hip spica cast for a femoral shaft fracture. The inner diameter of the polyethylene liner exchanged remained the same, 28 mm, in 21 hips; was downsized from 28 to 26 or 22 mm in 12 hips; and was upsized from 28 to 32 mm in 2 hips (Table 1). The objective was to provide for a minimum of 8-mm polyethylene thickness. The femoral head used in the existing or new femoral component was nonskirted in 18 hips and had a skirt in 17 hips. The objective with the use of these femoral heads was to equalize leg lengths. The new polyethylene liner was selected at the discretion of the surgeon and had an elevated rim in 20 hips and a standard rim in 15 hips. Standardized anteroposterior pelvis radiographs centered over the pubis were evaluated before and after liner exchange to measure the acetabular component abduction angle, and the anteversion angle was measured using the method of Ackland et al [11]. Sequential postoperative radiographs were evaluated to determine if the acetabular component tines were intact, bent, or broken. Pelvic osteolysis was measured using the method of Maloney et al [12]. Radiolucent lines of the acetabular component were described using the method of DeLee and Charnley [13]. The authors reviewed mechanical complications (dislocation, liner dislodgement, and loosening) after liner exchange without cement fixation. Statistical analysis of factors related to postoperative dislocation (head size, cup abduction and anteversion angles, and type of liner implanted) included paired student t test and Fisher exact test, with significance set at the P b .05 level.
Results For the purpose of determining the prevalence of spontaneous polyethylene liner dislodgement,
HGP component
Follow-up liner exchange (y)
Total follow-up acetabular shell in situ (y)
Acetabular abduction angle (8)
Acetabular anteversion (8)
Index head (mm)
Revision head (mm)
Revision liner
Patient
Sex
Age at index surgery (y)
AB01 AG14 AM30
F M F
66 68 73
I I I
8 3 2
15 9 6
56 44 50
0 6 5
32 28 28
28 28 28
Elevated Elevated Standard
BB02 BC06 BD09 CB34 CH31 DB04 DP23
F F F M F M M
25 28 54 23 55 21 42
I I II I I I I
6 5 3 2 5 9 10
12 16 11 11 9 18 17
64 34 44 43 38 48 42
2 2 7 0 4 7 6
32 28 28 28 28 28 28
26 22 28 28 28 26 22
Elevated Elevated Standard Elevated Elevated Elevated Standard
FE11 GD07 JB05 JE10 JE12 JF13 JO22
M F F M M M F
52 23 44 75 43 38 36
I I II II I I I
4 4 5 10 4 10 4
17 17 12 12 18 14 12
43 40 46 66 40 50 43
1 6 7 0 3 3 7
32 28 28 32 28 32 28
32 28 26 28 28 28 28
Elevated Standard Elevated Elevated Elevated Elevated Standard
LK32 LR25 LT29 MD08 NO21 PN20 PR26 RI15 RI16 RJ17 RM19 RS28 SE35 SR27 VL18
F M F M F F F M M F M M F F F
41 38 30 35 51 59 37 34 34 31 54 56 71 55 43
I I I I I I I I I I I I I I I
5 3 0.25 2 4 7 9 3 9 4 7 0.5 4 11 4
20 17 6 13 11 10 18 16 19 17 14 11 15 13 18
36 41 38 40 40 40 25 36 36 44 44 48 40 46 45
5 5 2 2 2 6 6 5 7 8 7 3 5 7 2
28 28 28 28 28 28 32 28 28 28 28 28 28 28 28
28 28 28 26 28 28 28 28 28 26 28 32 28 28 28
Elevated Standard Elevated Elevated Standard Elevated Elevated Elevated Standard Standard Standard Standard Elevated Standard Elevated
VP24
F
78
I
0.25
14
34
5
28
32
Standard
WB03 WH33
M M
39 51
I I
6 5
14 7.5
47 50
10 8
28 32
28 28
Standard Standard
Dislocation No No Yes, late resection No No No No Yes, resection No Yes, acetabular revision No No No No No No Yes, modular revision No No No No No No No No No No No No No No Yes, revision, constrained Yes, revision constrained No Yes, acetabular revision
994 The Journal of Arthroplasty Vol. 21 No. 7 October 2006
Table 1. Linear Exchange
Polyethlene Liner Dislodgement in HGP Acetabular Components ! Lachiewicz and Soileau
complete clinical and radiographic follow-up was available for 400 HGP-I acetabular components with a mean follow-up time of 10 years (range, 2-19 years) and 78 HGP-II acetabular components with a mean follow-up time of 8 years (range, 2-13 years). During this observation period, only one HGP-I acetabular component (0.2%) had spontaneous polyethylene liner dislodgement at 12 years postoperatively. This was from a 79-yearold woman who had an uncemented revision of an infected cemented bipolar prosthesis. She had a standard 28-mm polyethylene liner and a blongQ 28-mm femoral head (skirted) on an uncemented Biologic Ingrowth Anatomic System femoral component. The patient had multiple episodes of subluxation during these 12 years, but did not require reduction for a dislocation. She presented at 12 years with metal grinding in the hip and trochanteric bursitis. The senior author performed 35 liner exchanges, without cement in 32 HGP-I and 3 HGP-II components, between 1990 and 2001. Thirty-two hips had the index procedure performed by the senior author. There were 19 primary arthroplasties and 16 revision arthroplasties. There were 19 female and 16 male patients with a mean age of 53.6 years (range, 30-95 years). At the time of liner exchange, the index acetabular component had been in situ for a mean of 7.7 years (range, 1-13 years). The indications for exchange of the polyethylene liner were pelvic osteolysis and polyethylene wear in 3, recurrent dislocation in 3, periprosthetic fracture in 2, reoperation for leg length discrepancy in 1, debridement of infection in 1, and spontaneous liner dislodgement in 1. During 24 revisions for loosening of a femoral component, the polyethylene liner was exchanged without cement for wear. After polyethylene liner exchange without cement, 32 hips were followed for a mean of 5.1 years (range, 2-11 years). One hip had multiple early dislocations and was re-revised before 6 months and 2 other patients refused to return for follow-up after 6 months. At the time of recent follow-up, the original acetabular component metal shell had been in situ for a mean of 13.7 years (range, 6-19 years). No replaced polyethylene liner has dislodged during this time of observation.
995
follow-up. A bent tine was seen in 1 hip and a broken tine was seen in 1 hip. Pelvic osteolysis was seen in 6 hips (17%) after liner exchange. A nonprogressive radiolucent line was seen in 1 zone in 9 hips (26%). Complications The major complication of polyethylene liner exchange in this study was dislocation of the hip in 7 hips (20%). There were 5 early posterior dislocations treated with closed reduction and immobilization. There were 2 late dislocations, 1 posterior at 9 years and 1 anterior at 5 years associated with acetabular component loosening. All 7 dislocations were recurrent and required reoperation or revision. In 2 hips, a constrained acetabular component was implanted; 2 hips had acetabular component revision; 2 had resection arthroplasty (1 for infection and 1 for inability to reduce a chronic dislocation); and 1 had a modular revision with a 40-mm head. Several radiographic and clinical factors were analyzed to determine any association with dislocation after polyethylene liner exchange. There was no significant correlation between change in the femoral head size and the prevalence of dislocation ( P = .86). There were no significant associations between acetabular abduction angle ( P N .05) and anteversion angle ( P N .05) and dislocation, at least within the ranges seen. There was also no significant correlation between the use of a femoral head with a skirt and dislocation ( P N .05). There was a significant correlation between the type of polyethylene liner implanted and the risk of dislocation. There were 2 dislocations in 20 hips (10%) in which a 108 elevated rim liner was implanted and 5 dislocations in 15 hips (33%) in which a standard liner was used ( P = .04). In addition to the reoperations for recurrent dislocation, there was 1 late infection, which required removal of the implant, 3 hips required femoral re-revision for loosening, and 1 additional hip had a repeat liner exchange for wear and subluxation at another institution at 9 years.
Discussion Radiographic Results The mean abduction angle of the 35 acetabular components was 43.58 (range, 258-668) and the mean acetabular component anteversion was 4.68 (range, 08-108) (Table 1). In 33 acetabular components, the tines were intact at the most recent
The prevalence of polyethylene liner dislodgement was 0.2% in this study of 478 HGP-I and HGP-II acetabular components. Jacobs et al [14] reported 0.7% (4/560) liner dislodgement with the HGP-I component and 1.3% (6/476) HGP-II components in a review of their joint arthroplasty
996 The Journal of Arthroplasty Vol. 21 No. 7 October 2006 registry. One purpose of this study was to determine if polyethylene liner exchange without cement could be performed safely with the HGP-I or HGP-II acetabular component shell if the tines were intact. Modular exchange of the polyethylene liner and femoral head has been reported for recurrent dislocation [15,16]. In this study of 32 HGP-I and 3 HGP-II components, dislodgement of the replaced polyethylene liner has not occurred at a mean follow-up time of 5.1 years. It is important to note the difference between polyethylene liner exchange in the present study and that of Della Valle et al [3]. In that study, of the 18 patients undergoing reoperation for liner dislodgement, 17 were for HGP-II and only 1 was for an HGP-I component [3]. Broken tines were seen in 6 of those components and there were multiple mechanisms of failure. In the present study, 32 of the acetabular components were HGP-I components and only 3 were HGP-II components. Although the number of sets of tines for liner fixation was increased, the tines of the HGP-II were fabricated of weaker commercially pure titanium rather than titanium alloy. In addition, the polyethylene liners placed with HGP-II components were thinner for the same size component because of the thicker metal shell. These 2 changes may have caused a higher rate of dislodgement with the HGP-II component. At the time of polyethylene liner exchange, all tines were intact in the 35 hips in this study. Following this review, the author has recently revised 2 patients with HGP-II liner dislodgement, both of whom had multiple broken tines. In this clinical situation, the author recommends cementing a new liner, as the remaining tines will not firmly hold a new liner. If the metal shell is well fixed, areas of periacetabular osteolysis are treated by curettage and grafting. Werle et al [6] reported 7 cases of polyethylene liner dissociation of 5 HGP-II and 2 HGP-I acetabular components. Of the 7 hips, 4 had a femoral head with a bskirtedQ neck. All 7 hips had tine bdeformationQ and all had eccentric wear or polyethylene liner rim fracture. Werle et al recommended revising the entire shell for liner dissociation, even if the acetabular component was securely fixed and well positioned. We disagree with this recommendation and will cement a new liner only if the locking mechanism is damaged. Polyethylene liner exchange of the HGP-I and HGP-II acetabular component is not a simple innocuous procedure. This series had an unacceptably high rate (20%) of hip dislocation after polyethylene liner exchange. All dislocations were recurrent and required re-revision or reoperation.
There was no association with change in femoral head size, presence of a skirted femoral head, or acetabular component position, at least within the ranges seen. It is possible that with a larger patient population, femoral head size may be a significant factor in lowering the risk of dislocation. There was a significantly lower rate of dislocation (10% vs 33%) when a 108 elevated rim polyethylene liner was implanted. The use of an elevated rim polyethylene liner to reduce the prevalence of dislocation in revision total hip arthroplasty has been reported in a large series from the Mayo Clinic [17]. At the present time, the author routinely uses an elevated rim polyethylene liner when liner exchange is performed. If a new femoral head is implanted, the size is kept the same or upsized to articulate with a highly cross-linked polyethylene liner. In addition, over the past 2 years, the patient is measured preoperatively for a hip orthosis to limit flexion and adduction and it is worn prophylactically for 6 weeks. The senior author continues to follow these patients closely to determine if liner dislodgement or osteolysis will increase in prevalence.
Acknowledgments The authors thank Dr Donald Kirkendall for statistical analysis and Dr Peter Messick for assistance with patient record review.
References 1. Brian WW, Salvati EA, Wright TM, et al. Dissociation of acetabular components after total hip arthroplasty. Report of four cases. J Bone Joint Surg 1990; 72:1548. 2. Cameron HU. Dissociation of a polyethylene liner from an acetabular cup. Orthop Rev 1993;22:1160. 3. Della Valle AG, Ruzo PS, Li S, et al. Dislodgement of polyethylene liners in first and second-generation Harris-Galante acetabular components. A report of eighteen cases. J Bone Joint Surg 2001;83-A:553. 4. Louwerse RT, Heyligers IC. Late failure of the polyethylene liner fixation in an uncemented total hip arthroplasty. J Arthroplasty 1999;14:391. 5. Star MJ, Colwell Jr CW, Donaldson III WF, et al. Dissociation of modular hip arthroplasty components after dislocation. A report of three cases at differing dissociation levels. Clin Orthop 1992;278:111. 6. Werle J, Goodman S, Schurman D. Polyethylene liner dissociation in Harris-Galante acetabular components. J Arthroplasty 2002;17:78. 7. Clohisy JC, Harris WH. The Harris-Galante porouscoated acetabular component with screw fixation. An average ten-year follow-up study. J Bone Joint Surg Am 1999;81:66.
Polyethlene Liner Dislodgement in HGP Acetabular Components ! Lachiewicz and Soileau 8. Crowther JD, Lachiewicz PF. Survival and polyethylene wear of porous-coated acetabular components in patients less than fifty years old. Results at nine to fourteen years. J Bone Joint Surg 2002;89-A:729. 9. Latimer HA, Lachiewicz PF. Porous-coated acetabular components with screw fixation. Five to ten year results. J Bone Joint Surg 1996;78-A:975. 10. Archibeck MJ, Berger RA, Jacobs JJ, et al. Secondgeneration cementless total hip arthroplasty. Eight to eleven-year results. J Bone Joint Surg 2001; 83-A:1666. 11. Ackland MK, Bourne WB, Uhthoff HK. Anteversion of the acetabular cup. Measurement of angle after total hip replacement. J Bone Joint Surg Br 1986; 68:409. 12. Maloney WJ, Herzwurm P, Paprosky W, et al. Treatment of pelvic osteolysis associated with a stable acetabular component inserted without cement as part of a total hip replacement. J Bone Joint Surg Am 1997;79:1628.
997
13. DeLee JG, Charnley J. Radiological demarcation of cemented sockets in total hip replacement. Clin Orthop 1976;121:20. 14. Jacobs JJ, Rosenberg AG, Galante JO, et al. Letter regarding dislodgement of polyethylene liners in first and second-generation Harris-Galante acetabular components. A report of eighteen cases. J Bone Joint Surg 2001;84-A:143. 15. Lachiewicz PF, Soileau BS, Ellis J. Modular revision for recurrent dislocation of primary and revision total hip arthroplasty. J Arthroplasty 2004;19:424. 16. Toomey SD, Hopper Jr RH, McAuley JP, et al. Modular component exchange for treatment of recurrent dislocation of a total hip replacement in selected patients. J Bone Joint Surg Am 2001; 83:1529. 17. Cobb TK, Morrey BF, Ilstrup DM. The elevated-rim acetabular liner in total hip arthroplasty; relationship to postoperative dislocation. J Bone Joint Surg Am 1996;78:80.
Polyethylene Liner Exchange of the Harris-Galante Porous I and II Acetabular Components Without Cement Results and Complications Paul F. Lachiewicz, MD and Elizabeth S. Soileau, BSN, RN
Abstract: This study reviewed the long-term efficacy of the locking mechanism of the Harris-Galante porous (HGP) I and II acetabular components and the results and complications of polyethylene liner exchange without cement. There were 400 HGP-I components with a mean follow-up of 10 years (range, 2-19 years) and 78 HGP-II components with 8 years of mean follow-up (range, 2-13 years). There has been only 1 liner dislodgement (0.2%). Thirty-five hips (34 patients) have undergone liner exchange without cement. The index acetabular component was implanted as a primary procedure in 19 hips and a revision in 16 hips. No exchanged liner has dislodged at a mean follow-up time of 5.1 years (range, 2-11 years). However, there have been 7 patients (20%) with recurrent dislocation and all required reoperation. Dislocation was significantly lower when an elevated rim liner was used. Key words: polyethylene liner exchange, dislodgement, acetabular component. n 2006 Elsevier Inc. All rights reserved.
were dissatisfied with the 4.5- and 5.1-mm screws, which were somewhat difficult to implant. The Harris-Galante porous II acetabular component (HGP-II) had a shell thickness of 5.6 mm to accommodate the hex head 6.5-mm screws. The polyethylene liner was held in place by 4 or 5 sets of tines (fabricated of commercially pure titanium), based on the size of the component. The results of the HGP-II component are also excellent at 8 to 11 years of follow-up [10]. Dissociation of the polyethylene liner from cementless acetabular components was reported in 28 cases by Louwerse and Heyligers [4]. Of 28 cases with liner dissociation, 13 had a HarrisGalante acetabular component that had been in situ for a mean of 27 months. Della Valle et al [3] reported liner dislodgement in 17 HGP-II and 1 HGP-I acetabular components, which had been in situ for a mean of 7 years. Broken tines were seen in 6 cases, and there were multiple mechanisms of failure including polyethylene wear, fatigue fracture of tines, and fracture of the polyethylene rim.
Polyethylene liner dissociation from cementless acetabular components has been widely reported [1-6]. The Harris-Galante porous I titanium fiber metal-coated acetabular component (HGP-I) has been shown to have excellent bone ingrowth and long-term survival [7-9]. However, the polyethylene liner locking mechanism has been considered bprimitiveQ compared with present-day components. The metal shell thickness of the HGP-I acetabular component was 4.7 mm, and the polyethylene liner was held in place with 3 sets of titanium alloy btinesQ (Fig. 1). Although the early results of this component were very good, surgeons From the Department of Orthopaedics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina. Submitted October 30, 2004; accepted June 25, 2005. No benefits or funds were received in support of the study. Reprint requests: Paul F. Lachiewicz, MD, Department of Orthopaedics, University of North Carolina at Chapel Hill, 3151 Bioinformatics Bldg, CB 7055, Chapel Hill, NC 27599-7055. n 2006 Elsevier Inc. All rights reserved. 0883-5403/06/1906-0004$32.00/0 doi:10.1016/j.arth.2005.06.019
992
Polyethlene Liner Dislodgement in HGP Acetabular Components ! Lachiewicz and Soileau
Fig. 1. Left, HGP-I acetabular component with 3 sets of tines. Right, HGP-II acetabular component with 5 sets of tines.
These authors expressed concern about repeat dislodgement if a new liner was placed into these acetabular shells. They recommended revising a well-fixed shell or cementing a liner into the existing shell. It was also recommended to downsize the modular femoral head to 22 mm to provide for a thicker polyethylene liner. However, there were no data reported on the results or complications of reoperation in these 18 patients. One purpose of the present study was to determine the prevalence of polyethylene liner dislodgement in HGP-I and HGP-II acetabular components implanted by the author. In addition, this study was performed to test the hypothesis that, in the short term, there would be adequate fixation of the polyethylene liner in these acetabular components when revision including liner exchange without cement was performed. The mechanical complications after polyethylene liner exchange were also investigated.
Materials and Methods This is a retrospective study of 429 HGP-I and 87 HGP-II (both Zimmer, Warsaw, Ind) implanted by one surgeon at one hospital. Demographic, clinical, and radiographic data were prospectively stored in the surgeon’s total hip database. Patients (38 hips) had died with less than 2 years of follow-up (identified by ancestry.com), but none had a problem with the total hip arthroplasty. All patients who had a reoperation that included a polyethylene liner exchange without cement were identified. Demographic variables, such as patient age and sex,
993
preoperative diagnosis, and time the shell was in situ were extracted from the database. The operative records, radiographs, follow-up time, and complications after liner exchange were then reviewed. The technique for polyethylene liner exchange involved the posterior approach, with exposure of the entire rim of the acetabular component and checking the integrity of the tines. The tines were bent in slightly using a needle holder and a new polyethylene liner was tapped into place. The polyethylene liner was checked for blever-outQ and rotational stability with a clamp. Repair of the posterior capsule and external rotators was performed in all cases. Postoperatively, the patients were not given any immobilization, except for one patient who was placed into a hip spica cast for a femoral shaft fracture. The inner diameter of the polyethylene liner exchanged remained the same, 28 mm, in 21 hips; was downsized from 28 to 26 or 22 mm in 12 hips; and was upsized from 28 to 32 mm in 2 hips (Table 1). The objective was to provide for a minimum of 8-mm polyethylene thickness. The femoral head used in the existing or new femoral component was nonskirted in 18 hips and had a skirt in 17 hips. The objective with the use of these femoral heads was to equalize leg lengths. The new polyethylene liner was selected at the discretion of the surgeon and had an elevated rim in 20 hips and a standard rim in 15 hips. Standardized anteroposterior pelvis radiographs centered over the pubis were evaluated before and after liner exchange to measure the acetabular component abduction angle, and the anteversion angle was measured using the method of Ackland et al [11]. Sequential postoperative radiographs were evaluated to determine if the acetabular component tines were intact, bent, or broken. Pelvic osteolysis was measured using the method of Maloney et al [12]. Radiolucent lines of the acetabular component were described using the method of DeLee and Charnley [13]. The authors reviewed mechanical complications (dislocation, liner dislodgement, and loosening) after liner exchange without cement fixation. Statistical analysis of factors related to postoperative dislocation (head size, cup abduction and anteversion angles, and type of liner implanted) included paired student t test and Fisher exact test, with significance set at the P b .05 level.
Results For the purpose of determining the prevalence of spontaneous polyethylene liner dislodgement,
HGP component
Follow-up liner exchange (y)
Total follow-up acetabular shell in situ (y)
Acetabular abduction angle (8)
Acetabular anteversion (8)
Index head (mm)
Revision head (mm)
Revision liner
Patient
Sex
Age at index surgery (y)
AB01 AG14 AM30
F M F
66 68 73
I I I
8 3 2
15 9 6
56 44 50
0 6 5
32 28 28
28 28 28
Elevated Elevated Standard
BB02 BC06 BD09 CB34 CH31 DB04 DP23
F F F M F M M
25 28 54 23 55 21 42
I I II I I I I
6 5 3 2 5 9 10
12 16 11 11 9 18 17
64 34 44 43 38 48 42
2 2 7 0 4 7 6
32 28 28 28 28 28 28
26 22 28 28 28 26 22
Elevated Elevated Standard Elevated Elevated Elevated Standard
FE11 GD07 JB05 JE10 JE12 JF13 JO22
M F F M M M F
52 23 44 75 43 38 36
I I II II I I I
4 4 5 10 4 10 4
17 17 12 12 18 14 12
43 40 46 66 40 50 43
1 6 7 0 3 3 7
32 28 28 32 28 32 28
32 28 26 28 28 28 28
Elevated Standard Elevated Elevated Elevated Elevated Standard
LK32 LR25 LT29 MD08 NO21 PN20 PR26 RI15 RI16 RJ17 RM19 RS28 SE35 SR27 VL18
F M F M F F F M M F M M F F F
41 38 30 35 51 59 37 34 34 31 54 56 71 55 43
I I I I I I I I I I I I I I I
5 3 0.25 2 4 7 9 3 9 4 7 0.5 4 11 4
20 17 6 13 11 10 18 16 19 17 14 11 15 13 18
36 41 38 40 40 40 25 36 36 44 44 48 40 46 45
5 5 2 2 2 6 6 5 7 8 7 3 5 7 2
28 28 28 28 28 28 32 28 28 28 28 28 28 28 28
28 28 28 26 28 28 28 28 28 26 28 32 28 28 28
Elevated Standard Elevated Elevated Standard Elevated Elevated Elevated Standard Standard Standard Standard Elevated Standard Elevated
VP24
F
78
I
0.25
14
34
5
28
32
Standard
WB03 WH33
M M
39 51
I I
6 5
14 7.5
47 50
10 8
28 32
28 28
Standard Standard
Dislocation No No Yes, late resection No No No No Yes, resection No Yes, acetabular revision No No No No No No Yes, modular revision No No No No No No No No No No No No No No Yes, revision, constrained Yes, revision constrained No Yes, acetabular revision
994 The Journal of Arthroplasty Vol. 21 No. 7 October 2006
Table 1. Linear Exchange
Polyethlene Liner Dislodgement in HGP Acetabular Components ! Lachiewicz and Soileau
complete clinical and radiographic follow-up was available for 400 HGP-I acetabular components with a mean follow-up time of 10 years (range, 2-19 years) and 78 HGP-II acetabular components with a mean follow-up time of 8 years (range, 2-13 years). During this observation period, only one HGP-I acetabular component (0.2%) had spontaneous polyethylene liner dislodgement at 12 years postoperatively. This was from a 79-yearold woman who had an uncemented revision of an infected cemented bipolar prosthesis. She had a standard 28-mm polyethylene liner and a blongQ 28-mm femoral head (skirted) on an uncemented Biologic Ingrowth Anatomic System femoral component. The patient had multiple episodes of subluxation during these 12 years, but did not require reduction for a dislocation. She presented at 12 years with metal grinding in the hip and trochanteric bursitis. The senior author performed 35 liner exchanges, without cement in 32 HGP-I and 3 HGP-II components, between 1990 and 2001. Thirty-two hips had the index procedure performed by the senior author. There were 19 primary arthroplasties and 16 revision arthroplasties. There were 19 female and 16 male patients with a mean age of 53.6 years (range, 30-95 years). At the time of liner exchange, the index acetabular component had been in situ for a mean of 7.7 years (range, 1-13 years). The indications for exchange of the polyethylene liner were pelvic osteolysis and polyethylene wear in 3, recurrent dislocation in 3, periprosthetic fracture in 2, reoperation for leg length discrepancy in 1, debridement of infection in 1, and spontaneous liner dislodgement in 1. During 24 revisions for loosening of a femoral component, the polyethylene liner was exchanged without cement for wear. After polyethylene liner exchange without cement, 32 hips were followed for a mean of 5.1 years (range, 2-11 years). One hip had multiple early dislocations and was re-revised before 6 months and 2 other patients refused to return for follow-up after 6 months. At the time of recent follow-up, the original acetabular component metal shell had been in situ for a mean of 13.7 years (range, 6-19 years). No replaced polyethylene liner has dislodged during this time of observation.
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follow-up. A bent tine was seen in 1 hip and a broken tine was seen in 1 hip. Pelvic osteolysis was seen in 6 hips (17%) after liner exchange. A nonprogressive radiolucent line was seen in 1 zone in 9 hips (26%). Complications The major complication of polyethylene liner exchange in this study was dislocation of the hip in 7 hips (20%). There were 5 early posterior dislocations treated with closed reduction and immobilization. There were 2 late dislocations, 1 posterior at 9 years and 1 anterior at 5 years associated with acetabular component loosening. All 7 dislocations were recurrent and required reoperation or revision. In 2 hips, a constrained acetabular component was implanted; 2 hips had acetabular component revision; 2 had resection arthroplasty (1 for infection and 1 for inability to reduce a chronic dislocation); and 1 had a modular revision with a 40-mm head. Several radiographic and clinical factors were analyzed to determine any association with dislocation after polyethylene liner exchange. There was no significant correlation between change in the femoral head size and the prevalence of dislocation ( P = .86). There were no significant associations between acetabular abduction angle ( P N .05) and anteversion angle ( P N .05) and dislocation, at least within the ranges seen. There was also no significant correlation between the use of a femoral head with a skirt and dislocation ( P N .05). There was a significant correlation between the type of polyethylene liner implanted and the risk of dislocation. There were 2 dislocations in 20 hips (10%) in which a 108 elevated rim liner was implanted and 5 dislocations in 15 hips (33%) in which a standard liner was used ( P = .04). In addition to the reoperations for recurrent dislocation, there was 1 late infection, which required removal of the implant, 3 hips required femoral re-revision for loosening, and 1 additional hip had a repeat liner exchange for wear and subluxation at another institution at 9 years.
Discussion Radiographic Results The mean abduction angle of the 35 acetabular components was 43.58 (range, 258-668) and the mean acetabular component anteversion was 4.68 (range, 08-108) (Table 1). In 33 acetabular components, the tines were intact at the most recent
The prevalence of polyethylene liner dislodgement was 0.2% in this study of 478 HGP-I and HGP-II acetabular components. Jacobs et al [14] reported 0.7% (4/560) liner dislodgement with the HGP-I component and 1.3% (6/476) HGP-II components in a review of their joint arthroplasty
996 The Journal of Arthroplasty Vol. 21 No. 7 October 2006 registry. One purpose of this study was to determine if polyethylene liner exchange without cement could be performed safely with the HGP-I or HGP-II acetabular component shell if the tines were intact. Modular exchange of the polyethylene liner and femoral head has been reported for recurrent dislocation [15,16]. In this study of 32 HGP-I and 3 HGP-II components, dislodgement of the replaced polyethylene liner has not occurred at a mean follow-up time of 5.1 years. It is important to note the difference between polyethylene liner exchange in the present study and that of Della Valle et al [3]. In that study, of the 18 patients undergoing reoperation for liner dislodgement, 17 were for HGP-II and only 1 was for an HGP-I component [3]. Broken tines were seen in 6 of those components and there were multiple mechanisms of failure. In the present study, 32 of the acetabular components were HGP-I components and only 3 were HGP-II components. Although the number of sets of tines for liner fixation was increased, the tines of the HGP-II were fabricated of weaker commercially pure titanium rather than titanium alloy. In addition, the polyethylene liners placed with HGP-II components were thinner for the same size component because of the thicker metal shell. These 2 changes may have caused a higher rate of dislodgement with the HGP-II component. At the time of polyethylene liner exchange, all tines were intact in the 35 hips in this study. Following this review, the author has recently revised 2 patients with HGP-II liner dislodgement, both of whom had multiple broken tines. In this clinical situation, the author recommends cementing a new liner, as the remaining tines will not firmly hold a new liner. If the metal shell is well fixed, areas of periacetabular osteolysis are treated by curettage and grafting. Werle et al [6] reported 7 cases of polyethylene liner dissociation of 5 HGP-II and 2 HGP-I acetabular components. Of the 7 hips, 4 had a femoral head with a bskirtedQ neck. All 7 hips had tine bdeformationQ and all had eccentric wear or polyethylene liner rim fracture. Werle et al recommended revising the entire shell for liner dissociation, even if the acetabular component was securely fixed and well positioned. We disagree with this recommendation and will cement a new liner only if the locking mechanism is damaged. Polyethylene liner exchange of the HGP-I and HGP-II acetabular component is not a simple innocuous procedure. This series had an unacceptably high rate (20%) of hip dislocation after polyethylene liner exchange. All dislocations were recurrent and required re-revision or reoperation.
There was no association with change in femoral head size, presence of a skirted femoral head, or acetabular component position, at least within the ranges seen. It is possible that with a larger patient population, femoral head size may be a significant factor in lowering the risk of dislocation. There was a significantly lower rate of dislocation (10% vs 33%) when a 108 elevated rim polyethylene liner was implanted. The use of an elevated rim polyethylene liner to reduce the prevalence of dislocation in revision total hip arthroplasty has been reported in a large series from the Mayo Clinic [17]. At the present time, the author routinely uses an elevated rim polyethylene liner when liner exchange is performed. If a new femoral head is implanted, the size is kept the same or upsized to articulate with a highly cross-linked polyethylene liner. In addition, over the past 2 years, the patient is measured preoperatively for a hip orthosis to limit flexion and adduction and it is worn prophylactically for 6 weeks. The senior author continues to follow these patients closely to determine if liner dislodgement or osteolysis will increase in prevalence.
Acknowledgments The authors thank Dr Donald Kirkendall for statistical analysis and Dr Peter Messick for assistance with patient record review.
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Polyethlene Liner Dislodgement in HGP Acetabular Components ! Lachiewicz and Soileau 8. Crowther JD, Lachiewicz PF. Survival and polyethylene wear of porous-coated acetabular components in patients less than fifty years old. Results at nine to fourteen years. J Bone Joint Surg 2002;89-A:729. 9. Latimer HA, Lachiewicz PF. Porous-coated acetabular components with screw fixation. Five to ten year results. J Bone Joint Surg 1996;78-A:975. 10. Archibeck MJ, Berger RA, Jacobs JJ, et al. Secondgeneration cementless total hip arthroplasty. Eight to eleven-year results. J Bone Joint Surg 2001; 83-A:1666. 11. Ackland MK, Bourne WB, Uhthoff HK. Anteversion of the acetabular cup. Measurement of angle after total hip replacement. J Bone Joint Surg Br 1986; 68:409. 12. Maloney WJ, Herzwurm P, Paprosky W, et al. Treatment of pelvic osteolysis associated with a stable acetabular component inserted without cement as part of a total hip replacement. J Bone Joint Surg Am 1997;79:1628.
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13. DeLee JG, Charnley J. Radiological demarcation of cemented sockets in total hip replacement. Clin Orthop 1976;121:20. 14. Jacobs JJ, Rosenberg AG, Galante JO, et al. Letter regarding dislodgement of polyethylene liners in first and second-generation Harris-Galante acetabular components. A report of eighteen cases. J Bone Joint Surg 2001;84-A:143. 15. Lachiewicz PF, Soileau BS, Ellis J. Modular revision for recurrent dislocation of primary and revision total hip arthroplasty. J Arthroplasty 2004;19:424. 16. Toomey SD, Hopper Jr RH, McAuley JP, et al. Modular component exchange for treatment of recurrent dislocation of a total hip replacement in selected patients. J Bone Joint Surg Am 2001; 83:1529. 17. Cobb TK, Morrey BF, Ilstrup DM. The elevated-rim acetabular liner in total hip arthroplasty; relationship to postoperative dislocation. J Bone Joint Surg Am 1996;78:80.