The Journal of Arthroplasty Vol. 23 No. 1 2008

A New Cemented Femoral Stem

A Prospective Study of the Stryker Accolade C With2- to 5-Year Follow-Up

Muhammad Ajmal, MD, Amar S. Ranawat, MD, and Chitranjan S. Ranawat, MD

Abstract: This prospective study evaluates the short-term results of a recently releasedcemented femoral stem design in primary cemented and hybrid total hip arthroplasty(THA). There were 100 all-cemented and 100 hybrid THAs in the 2-year study group.Good to excellent results were obtained in 96%. There was one reoperation forrecurrent dislocation in each cohort (1%) and one single-staged reoperation for sepsisin the cemented cohort. There were 47 THA available for 5-year follow-up. Good toexcellent results were maintained in 98%. One additional patient had a revisionbecause of late recurrent dislocation. This study has demonstrated excellent earlyresults and safety with this cemented femoral stem. The features include a dual-wedgegeometrywith a 0.88-μmRa surface roughness, proximalmacro-normalizations, distalanti-rotation grooves, and an optimized head-and-neck ratio approaching 4:1 using astandard 28-mm head. Key words: THA, outcomes.© 2008 Elsevier Inc. All rights reserved.

Since the introduction of the concept of low-frictionarthroplasty by Charnley [1] in the early 1960s, theuse of cement has been the gold standard forfixation during total hip arthroplasty (THA) and isthe most popular method of femoral componentfixation worldwide [2]. The durability of cementedfemoral stems is predicated upon several variables,some of which are patient-dependent, implant-dependent, and technique-dependent.This prospective study evaluates the early results,

safety, and efficacy of the cemented Accolade C

From the Orthopaedic Department, V.A. Hospital, Nashville,Tennessee.

Submitted April 8, 2007; accepted August 8, 2007.Benefits or funds were received in partial or total support of

the research material described in this article. These benefits orsupport were received from the following sources Amar S.Ranawat, MD, and Chitranjan S. Ranawat, MD, are consultantsfor Stryker Orthopaedics, Inc (Allendale, NJ).

Reprint requests: Amar S. Ranawat, MD, The Department ofOrthopaedic Surgery, Ranawat Orthopedic Center, Lenox HillHospital, 130 East 77th Street, 11th Floor, New York, New York10021.

© 2008 Elsevier Inc. All rights reserved.0883-5403/08/2301-0020$34.00/0doi:10.1016/j.arth.2007.08.008

118

femoral component (Stryker Orthopaedics, Inc,Allendale, NJ) in hybrid and cemented primaryTHAs. Although this design represents an evolutionand not a revolution in cemented stem design, it isimportant to report early results with any newdesign change. This is especially true in light of thefact that many commercially available implants incurrent use have never been subject to peer review.

Materials and Methods

Between August 2000 and February 2003, thesenior surgeon (blinded) prospectively implanted487 nonconsecutive primary THA (223 all-cemen-ted and 264 hybrid) using a cemented femoral stemwith a modified third-generation cement techniqueand a posterolateral approach. The first 100 con-secutive patients from each cohort who met the2-year follow-up criteria were included. From these200 patients, 47 patients are also available with5-year follow-up.

The indication for cemented THA included allpatients older than 60 years at the time of the indexprocedure. In patients younger than 60 years, a

Fig. 1. Stryker Accolade C femoral stem with assembledmodular head.

A New Cemented Femoral Stem � Ajmal et al 119

radiographic evaluation of bone quality was per-formed using the cortical index [3]. Patients whoseindex was greater than 38% were implanted with anoncemented THA, whereas the remaining patientsreceived hybrid THA.Additional indications for hybrid THA included

patients older than 60 years in whom excessivebleeding, extensive acetabular cysts (N1 cm), dys-plastic sockets (b80% implant capture), or theabsence of healthy acetabular cancellous boneprecluded the ability to adequately cement an all-polyethylene socket.The femoral component used was the Stryker

Accolade C in all cases. This design has evolved outof the experience with the Osteonics OmnifitCemented Stem (Stryker) and the Ranawat-Bur-stein (RB) Cemented stem (Biomet, Warsaw, Ind)with the addition of several advanced features. Thecomponent (Fig. 1) is made of a forged chromiumcobalt alloy with a dual-wedge design. It hasproximal macro-normalizations and distal anti-rotation grooves. The head-neck ratio with a28-mm head is 3.5:1 in anteroposterior plane and2.2:1 in mediolateral plane. The neck is polished and

has a small collar for accurate positioning andcement containment. The stem body has surfaceroughness (Ra) of approximately 0.88 μm (satinfinish). The femoral stem is coupled with a modularforged Vitallium alloy femoral head (Stryker Ortho-paedics, Inc., Allendale, NJ).

The cemented THAs were implanted with either adirect compression-molded, all-polyethylene cup(RB, Biomet) or a highly cross-linked, all-polyethy-lene cup (Trident, Stryker). The hybrid THAs wereimplanted with a modular, hemispherical, titanium,plasma-sprayed cementless shell (RB [Biomet] orTrident [Stryker]).

Clinical evaluations were done using the Hospitalfor Special Surgery (HSS) hip score [4] and apatient-administered questionnaire. Clinical failureswere expressed as revision of the femoral compo-nent in isolation or with the acetabular compo-nent for any cause including infection, dislocation,or loosening.

The radiographic evaluations were done using astandardized series of films that included weight-bearing anteroposterior view of the pelvis andanteroposterior and lateral views of the involvedhip at 6 weeks, 1 year, and at last follow-up forcomparison. The location and thickness of radi-olucent lines around the socket were describedusing the zones of DeLee and Charnley [5]. Socketloosening was evaluated using the methods ofMartell et al [6] and Ranawat et al [7] forcementless and cemented acetabular components,respectively. The femoral component was evaluatedaccording to methods described by Barrack et al [8].We accepted a stem position ±3° in the cement anda position outside that was either considered varusor valgus.

Results

Clinical Evaluation

In the cemented group, the average age was72 years (44-85 years) with an average follow-up of32 months (24-49 months). There were 71 femaleand 29 male patients with a preoperative diagnosisof osteoarthritis in 99 and hip fracture in 1. Theaverage HSS hip score improved from 23 to 36 (40 isthe highest score). Good to excellent results wereobtained in 96% of patients. There were 2 revisions.One reoperation was performed to address recur-rent dislocation in a patient with Parkinson disease3 months after the index procedure with 1%dislocation rate for the cemented group. The surgeryentailed removal of the femoral stem for improvedexposure followed by removal of the cemented cup

Fig. 2. Type A (white out) cement mantle.

120 The Journal of Arthroplasty Vol. 23 No. 1 January 2008

and conversion to a noncemented shell with aconstrained liner. A femoral component (one sizedown) was then reimplanted using the cement-in-cement technique. The second reoperation was asingle-stage revision of both components for delayedinfection 2 years after the index arthroplasty in apatient with HIV.In the hybrid group, the average age was 74 years

(47-85 years) with an average follow-up of31 months (24-48 months). There were 84 femaleand 16 male patients with a preoperative diagnosisof osteoarthritis in 91, developmental dysplasia ofhip (DDH) in 5, avascular necrosis (AVN) in 3 , andhip fracture in 1. Average preoperative HSS hipscores improved from 23 to 36. Good to excellentresults were obtained in 96% of patients. There wasone revision because of a traumatic dislocation2 years after the index arthroplasty with 1%dislocation rate for the hybrid group.Among all the 200 hips of this study, thigh pain

was absent in most of the patients reviewed. Tenpatients (5%) did report thigh symptoms, but allwere mild and intermittent. No patient reportedmoderate, severe, or disabling thigh pain inthe patient-administered questionnaire. Twelvepatients (6%) reported a persistent limp that wasrated as mild in 9 patients and moderate in3 patients. No one had a severe limp. Eighteenpatients (9%) used a cane for ambulation outdoors.All of these patients attributed their need for a caneto other medical reasons.Forty-seven patients were available for 5-year

review. Good to excellent results were maintainedin 98%. One additional patient with THA withhybrid fixation had a revision for late recurrentdislocation using the cement-in-cement technique.No additional acetabular or femoral component wasrevised or is pending revision as of this review.

Radiographic Evaluation

The average lateral inclination of the acetabularcomponent was 40° (range, 31°-49°) in the cemen-ted group and 43° (range, 29°-50°) in the hybridgroup. Of the cemented acetabular components,14 hips demonstrated nonprogressive (seen on initialpostoperative x-rays) interface lucency in zone 1,and 1 hip in zone 3. There were no continuous,progressive radiolucent lines of more than 1 mm inany zone.There were no cementless acetabular components

that demonstrated migration, global radiolucency,screw breakage, or osteolysis [6].Review of all the femoral components of 200

patients confirmed grade A (Fig. 2) cement mantle

in 86% (173 hips), grade B in 12% (24 hips), andgrade C1 in 1.5% (3 hips). In terms of stemalignment (±3°), neutral alignment was attained in98% (196 hips), valgus alignment in 2% (4 hips),and varus alignment in 1% (2 hips). There were noinstances of osteolysis or progressive radiolucentlines of more than 1 mm in thickness with reactivecortical “penciling” in any zones. There were nocases with incomplete radiolucent lines.

Discussion

This study shows that appropriate femoral stemgeometry and a good cement mantle can deliverexcellent short-term results. The design features ofthis stem include using a forged chromium-cobaltstems, dual-wedge geometry, gradual tapers, macro-normalizations, anti-rotation grooves, 0.88-μm Rasurface roughness, and increased head-to-neck ratios.

The proportionalized prosthesis with its increasingcross-sectional area has been shown to reduce theforces both within the implant and the cementmantle [9] and thus lowers the risk of aseptic

A New Cemented Femoral Stem � Ajmal et al 121

loosening, cement fracture, and consequent failure[10,11]. In addition, the proportional increments inneck length and offset with increasing sizes allow amore accurate reproduction of the anatomic geo-metry of the hip in terms of reconstruction of thecenter of rotation, offset, and limb length.One of the more intriguing aspects of this

current design has been the improvement in thehead-neck ratio (3.5:1) by narrowing the ante-roposterior diameter of the neck region. Bartz et al[12] have shown a significant decrease in compo-nent impingement when the head-neck ratio isgreater than 2:1. This has been accomplished inthe Accolade C through improved metallurgyallowing for increased range-of-motion beforeimpingement. In addition, the polished surface ofthe neck should minimize the abrasive effect onthe polyethylene should impingement occur.Whether these features will translate into lowerdislocation and wear rates remains to be seen, butour early results are encouraging.Another important feature of the femoral stem is

proximal macro-normalizations and distal anti-rotation grooves. These macrostructures are per-pendicular to the direction of principal loadtransfer and help avoid the development of hoopstresses, facilitate conversion of tensile forces tocompressive forces in the cement, and thus reducethe load-magnifying effect of the wedge-shapedstem. These simple alterations of the interfacegeometry result in improved ability of the stem tocarry higher loads and better transmission of theseloads to the surrounding cement and bone, as wellas enhancement of forces required to cause inter-face failure compared with smooth nonnormalizedstems [13].Although there is no consensus in the literature

with regard to the optimal surface roughness of acemented stem [14,15], the cemented stem with anRa of 0.75 to 1.0 μm (satin finish) has a proven trackrecord in our experience [16,17]. Other “nonpol-ished” designs such as the Harris Design-2 stem witha matte finish have demonstrated a survivorship of83% at 25 years with revision for any reason as endpoint [18]. An additional benefit of satin finish is theability to remove the stem without sacrificing thecement mantle and incorporating the “cement-in-cement technique” to improve acetabular exposurein the revision setting.We acknowledge the weakness of our study that

another 60% of the patients operated on during thesame time frame are not included in the results andcould theoretically have less successful results.However, the authors are unaware of any failuresin the nonreviewed group.

Our current experience with this cementedfemoral stem has been excellent. However, it cannotbe overstated that good surgical technique plays anequally important role. We continue to use cemen-ted femoral fixation in appropriate patients withlasting confidence.

References

1. Charnley J. Operative technique of low frictionarthroplasty of the hip joint, vol. 6. Wrightington,England: Internal Publication, Centre for Hip Surgery;1967. p. 1.

2. Herberts P, Malchau H. How outcome studies havechanged total hip arthroplasty practices in Sweden.Clin Orthop 1997;344:44.

3. Gruen T. A simple assessment of bone quality prior tohip arthroplasty: cortical index revisited. Acta OrthopBelg 1997;63:20.

4. Wilson Jr PD, Amstutz HC, Czerniecki A. Total hipreplacement with fixation by acrylic cement: apreliminary study of 100 consecutive McKee-Farrarprosthetic replacements. J Bone Joint Surg Am1972;54:207.

5. DeLee JG, Charnley J. Radiological demarcation ofcemented sockets in total hip replacement. ClinOrthop 1976;121:20.

6. Martell JM, Pierson III RH, Jacobs JJ. Primary total hipreconstruction with a titanium fiber-coated prosthesisinserted without cement. J Bone Joint Surg Am1993;75:554.

7. Ranawat CS, Deshmukh RG, Peters LE, et al.Prediction of the long-term durability of all-poly-ethylene cemented sockets. Clin Orthop 1995;317:89.

8. Barrack RL, Mulroy Jr RD, Harris WH. Improvedcementing techniques and femoral component loos-ening in young patients with hip arthroplasty: a12-year radiographic review. J Bone Joint Surg Br1992;74:385.

9. Crowninshield RD, Brand RA, Johnston RC, et al. Ananalysis of femoral component stem design in totalhip arthroplasty. J Bone Joint Surg Am 1980;62:68.

10. Beckenbaugh RD, Ilstrup DM. Total hip arthroplasty:a review of 333 cases with long follow-up. J BoneJoint Surg Am 1978;60:306.

11. Ebramzadeh E, Sarmiento A, MeKellop HA, et al. Thecement mantle in total hip arthroplasty. J Bone JointSurg Am 1994;76:77.

12. Bartz RL, Noble PC, Kadakia NR, et al. The effect offemoral component head size on posterior dislocationof the artificial hip joint. J Bone Joint Surg Am2000;82:1300.

13. Pugh J, Averill R, Pachtman N. Prosthesis design toresist loosening: stress normalization. Presented at the27th Annual Meeting of the Orthopaedic ResearchSociety, Las Vegas; 1981.

14. Huiskes T, Verdonschot N, Nivbrant B. Migration,stem shape and surface finish in cemented total hiparthroplasty. Clin Orthop 1998;355:103.

122 The Journal of Arthroplasty Vol. 23 No. 1 January 2008

15. Williams HDW, Browne G, Gie GA, et al. The Exe-ter universal cemented femoral component at 8 to12 years. J Bone Joint Surg Br 2002;84:324.

16. Rasquinha VJ, Ranawat CS, Dua V, et al. Aprospective, randomized, double-blind study ofsmooth versus rough stems using cement fixation:minimum 5-year follow-up. J Arthroplasty 2004;19(7 Suppl 2):2.

17. Ranawat CS, Ranawat AS, Rasquinha VJ. Masteringthe art of cemented femoral stem fixation. J Arthro-plasty 2004;19(4 Suppl 1):85.

18. SkutekM, Bourne RB, Rorabeck CH, et al. The twentyto twenty-five-year outcomes of the Harris design-2matte-finished cemented total hip replacement. Aconcise follow-up of a previous report. J Bone JointSurg Am 2007;89:814.