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Evaluation Of Subsidence Between Collarless And Collared Corail Femoral Cement Less Total Hip Replacement

Sudhahar TA, Morapudi S, Branes K

Department of Trauma and Orthopaedics, Macclesfield District General Hospital NHS Trust,
Macclesfield, UK.

Address for Correspondence:
Sudhahar TA,
5, Carolina road,
Great Sankey, 
Warrington, WA58DB.
01925 712 244, 07835258719


We are presenting our early results of femoral stem subsidence between collarless and collared Corail uncemented total hip replacement. There were 39 hips in 37 patients  in collarless group (A) and in collared group (B) 43 hips in 41 patients. Subsidence is seen in 24 hips (61.5%) in-group A and 8 hips (18.6%) in-group B.  Range of subsidence in-group A is 1-15mm and group-B is 1-6 mm. Despite this high number of subsidence only 2 in-group A and none in-group B lead to clinical failure of stems. Chi-Square test was used to show that collared prosthesis is more effective when it comes to subsidence (p-value<0.001). From our study we conclude that Corail collared uncemented stem is better than collarless stem in preventing subsidence.

J.Orthopaedics 2009;6(2)e3


Subsidence; Collarless stem; Corail stem; Uncemented stem; Uncemented THR ; Femoral stem.


We are presenting our early results of comparison of femoral subsidence between collared and collarless cementless Corail stem. There have been significant engineering advances since the advent of metal on polyethylene low friction arthroplasty.  Swedish hip registry(1)shows excellent 15 – 20 year survival Elite Charnley and Exeter cemented total hip arthroplasty in older population.  Most controversies in arthroplasties are in young and active people who want to go back to their active lifestyle.  Due to high demand on their hips various combination of articulations are available to use. We have used metal on metal articulation using large diameter femoral head and cementless procedure in this study. We have selected this articulation for young and active patients.

Materials and Methods:

We have retrospectively analysed the subsidence of femoral stem between collared and collarless stem.  This is an observational study. We collected the data from the case notes. Subsidence was measured between the original radiograph and final follow up. Data was collected for all Corail total hip replacement done between Nov 2003 and Feb 2006. All the procedures were done by our senior author or in his assistance by one of the specialist registrars. The procedure was done using standard lateral approach to the hip.

We have analysed the subsidence between Group A (collarless) and Group B (collared). At the time of the study only collared stem was in use in our hospital. This is non-randomised, consecutive single blinded study. The table I give the details of demography of patients in both groups and table II, the results of radiological measurement and subsidence.

Radiological(2) measurements were evaluated using Gruen zones for the stem. Signs of subsidence, radiolucent lines, endosteal bone formation (spot welds) and pedestal formation were used to assess fixation and stability of the stem according to Engh’s criteria.

There were39 hips with collarless stem (group A) and 43 hips with collared stem in (group B).

Inclusion criteria

  1. All primary Corail cementless THR performed between Nov 2003 and Feb 2006

  2. Revision for failed Dynamic hip screw and cannulated screws for intra-capsular fracture neck were included.

  3. Age less than 70 years.

Exclusion criteria

  1. Revision THR for aseptic and septic loosening

  2. Pathological process in femur

  3. Revision for periprosthetic fractures

Results :

In collarless group (A) there were 39 hips in 37 patients and in collared group (B) 43 hips in 41 patients. Demographic details are given in table I.  Average age in collarless group is 52.5 years (range 40-68 years) and in collared group 51.2 years (range 31-68 years). Sex ratio for group A (male 58 and female 56) and group B (male 61 and female 59 years.   Laterality in-group A (right –21 and left – 18 hips) and in group B (right – 26 and left – 17 hips.)




No of patients in the study

37 (39 hips)

41 (43 hips)

Age range



Mean age




L-18 & R-21

L-17 & R-26


Male- 58

Female- 56

Male- 61

Female- 59

Follow up (months)


(Mean - )


(Mean- )


38 primary OA and

1 fracture neck of femur

41 primary OA and 2 for failed cannulated screws

Hospital stay (days)

6.5 (5 – 9)

6 (5 –10)

Table I – Demographic details between collared and collarless group.

Average hospital stay in-group A is 6.5 days (range 5-9) and in-group B is 6 days (range 5-10). Follow up period in-group A is ranging from 2-27 months and group B 2-17 months. Diagnosis in-group A is primary osteoarthritis in 38 hips and one for fracture neck of femur. In group B is primary osteoarthritis in 41 hips and 2 for failed cannulated screws for treated fracture neck of femur.

There were no intra-operative complications in either of the groups. There were no femoral or acetabular fractures and no one needed bone grafting. No additional procedure done in any of the patients in either group.




Percentage of subsidence



Range of subsidence



Subsidence in each patient

24/39(6x1, 3x2, 4x3, 4x4, 1x5, 1x6, 3x7, 1x13, 1x15)

8/43 (4x1, 1x2, 2x3, 1x6)

No of revisions

2 (5.12%)


Pedestal formation



Varus of stem

9 (23%)

19 (44%)

Varus angluation range

1-4 degree

1-6 degree

Varus in immediate postoperative film


4 (3 – 6 degrees)


Progression of varus with weight bearing

Not assessed

3 – 3, 3- 5, 4 –5 , 6 –6


Table II - The results of radiological measurement and subsidence

Radiological measurements are given in table II. Varus alignment for stem in immediate post operative films group A is none and in group B is seen in 4 (3-6 degrees). Varus alignment in final follow up in group A ranges from 1-4 degrees in 9 (23%) of the stems and in group B ranges from 1-6 degrees in 19 (44%) of the stems. All these hips with varus stem remained stable and asymptomatic in both groups. There were no endosteal bone formation (spot welds) and pedestal formation in final follow up roentgenograms in both groups.

Subsidence, which is the main study of interest, is seen in 24 hips (61.5%) in-group A (Fig I) and 8 hips (18.6%) in-group B (Fig II). Range of subsidence in-group A is 1-15mm and group B is 1-6 mm. From the literature(3,4) review more than 3 mm of subsidence is taken as significant subsidence. In group A there were 11 hips with significant subsidence ( 4-4mm, 1-5mm, 1-6mm, 3-7mm, 1-13mm, 1-15mm) and group B one hip with significant subsidence of 6mm.  Despite this high number of subsidence only 2 in group in A and none in group B lead to clinical failure of stems.

Fig I- Subsidence in Collarless stem

Fig II- Subsidence in collared stem.  

Fig III – Collarless Corail hip initial post operative radiograph.

Fig IV – Corail hip showing subsidence of 15 mm at 2 year followup.

Total no of revisions in our study is 2 (5.12 %). Both are seen in collarless group. First one was due to recurrent dislocation with subsidence of 13mm.  The second one was for severe instability due to severe progressive subsidence of up to 15 mm (Fig III & Fig IV).  In collared stem there were no revisions. Chi-Square test was used to show that collared surgery is more effective when it comes to subsidence. At 95% confidence level, collared surgery is significantly more effective than collarless (p-value<0.001). 71% of patients undergoing collared surgery had no subsidence as compared to collarless where the figure was 25% who had no subsidence.  No relation between co-morbidities and outcome. No association between body mass index (BMI) and subsidence.

There were few post-operative complications, one patient had superficial infection treated with antibiotics, one had high temperature treated with antibiotics and one immediate dislocation treated by manipulation which was subsequently stable.  No patient required any additional procedure at any time during the study.

Excluding the subsidence in collarless group we don’t have any intra-operative complication in either of the groups. There were no femoral fractures and no one needed bone grafting.  No additional procedure done in any patient in either group.


Long-term results about most of the total hip arthroplasties are available in the literature(1). In old and frail patients cemented total hip arthroplasty(1) remains a gold standard.  Controversies still go on for young and active patients, the reason being unrealistic patient expectations(1) puts high demand and high cycles of loading leading to early failure. 

The second most frequently entered uncemented arthroplasty in national joint registry (UK) after Furlong HAC is Corail total hip replacement(5).  Early results for uncemented Corail hip arthroplasty is encouraging(4,6,7) with 1% revision rate in 4.5 years from Norwegian arthroplasty registry(6) and no signs of loosening in 11 years from Israel Orthopaedic association(4).  For Corail stem early results are encouraging from the available literature(4).  There are lots of uncemented prostheses available in the literature(8-10) with good medium term results.

The two types of stem we have used in this study is collared and collarless.  Collared as the name suggest has a collar and sits on the calcar to prevent subsidence.  Advantage in addition to preventing subsidence is reducing stress shielding proximally. Distal toggle is a theoretical disadvantage.  

Despite biomechanical factors being in favour of preventing subsidence it still happened in the collarless stem (Fig I &Fig IV). While achieving perfect fit with collared stem, it has the risk of femoral fracture and subsequently compromising the final results.  In our study we don’t have femoral fracture in both groups.  But using the collared stem reduces the risk of femoral fracture and also avoids progressive subsidence.

Conclusion :

From our study we conclude that Corail collared(11) uncemented stem is better than collarless stem in preventing subsidence. Literature shows evidence of subsidence in primary uncemented femoral stem(8,12,13,14) and  uncemented revision arthroplasty(15). The limitation of this study is the small number and shorter duration of follow up. Long-term results and survival analysis is beyond the scope of this study.

Reference :

  1. Henrik Makchau, Peter Herberts, Goran Garellick et all. Prognosis of total hip replacement. Arthroplasty registry 1979-2000. 2002.

  2. Shetty AA, Slack R, Tindall A, James KD, Rand C. J. Results of a hydroxyapatite-coated (Furlong) total hip replacement: a 13- to 15-year follow-up. J Bone Joint Surg Br; 87(8):1050-4, Aug 2005.

  3. A J Butt, G Weeks, W Curtin and K Kaar. Early experience with uncemented primary total hip arthroplasty using Corail stems and Duraloc cups. J Bone Joint Surg Br.- Orthopaedic Proceedings. Vol 87-B, Issue SUPP III, 269.

  4. Y.Khatib, O.Schwartz, D.G.Mendes and M.Said. Corail stem for total hip arthroplasty: 11 years of imaging follow-up. J Bone Joint Surg Br.- Orthopaedic proceedings Vol 84-B, Issue SUPP III, 301.

  5. National joint registry for England and Wales 1st annual report. Page 60, Sep 2004.

  6. Havelin LI, Espehaug B, Vollset SE, Engesaeter LB. Early aseptic loosening of uncemented femoral components in primary total hip replacement. A review based on the Norwegian Arthroplasty Register. J Bone Joint Surg Br. 1995 Jan;77(1):11-7. Erratum in: J Bone Joint Surg Br;77(6):985Nov 1995.

  7. Vidalain JP. HA coating. Ten –year experience with the CORAIL system in primary THA. The Artro group. Acta Orthop Belg, 63 Suppl 1:93-5; 1997.

  8. Meding JB, Keating EM, Ritter MA, Faris PM, Berend ME. Minimum ten-year follow-up of a straight-stemmed, plasma-sprayed, titanium-alloy, uncemented femoral component in primary total hip arthroplasty. J Bone Joint Surg Am, 86-A(1):92-7; Jan 2004.

  9. Mallory TH, Lombardi AV Jr, Leith JR,Fujita H,Hartman JF,Capps SG,Kefauver CA,Adams JB, Vorys GC. Minimal 10-year results of a tapered cementless femoral component in total hip arthroplasty, J Arthroplasty 16(8 Suppl 1): 49-54, Dec 2001.

  10. Teloken MA, Bissett G, Hozack WJ, Sharkey PF, Rothman RH.Ten to fifteen-year follow-up after total hip arthroplasty with a tapered cobalt-chromium femoral component (tri-lock) inserted without cement. J Bone Joint Surg Am, 84-A(12):2140-4; Dec 2002.

  11. Jean-Pierre Vidalain, MD.  Corail stem long term results based upon the 15-year Artro group experience. Reprint from: Jean- Alain Epinette, Michael T. Manley (Eds.) Fifteen years of  clinical experience with hydroxyapatite coatings in joint artrhoplasty pp217-224.

  12. Kim YH, Kim VE. Early migration of uncemented porous coated anatomic femoral component related to aseptic loosening. Clin Orthop Relat Res.;(295):146-55. Oct 1993.

  13. Lachiewicz PF, Anspach WE 3rd, DeMasi R. A prospective study of 100 consecutive Harris-Galante porous total hip arthroplasties. 2-5-year results. J Arthroplasty, 7(4):519-26. Dec1992.

  14. Morrey BF, Kavanagh BF. Mayo Clinic, Rochester, MN 55905. Complications with revision of the femoral component of total hip arthroplasty. Comparison between cemented and uncemented techniques. J Arthroplasty, 7(1):71-9; Mar 1992.

  15. Brindley GW, Adams R. Cementless revision of total hip arthroplasty using proximal porous-coated femoral implants. J South Orthop Assoc, 7(4):246-50; Winter 1998.

This is a peer reviewed paper 

Please cite as: Sudhahar TA: Evaluation of subsidence between collarless and collared Corail femoral cement less total hip replacement.

J.Orthopaedics 2009;6(2)e3





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