Why I do use uncemented implants

Jean-Luc LERAT Bernard MOYEN

(Centre Hospitalier Lyon-Sud)

11èmes Journées Lyonnaises de Chirurgie du genou

Oct 2004

• Since 30 years surgeons argue about the use of cement for TKA

Nevertheless

• Surgeons « cement non user » may appreciate to use cement in special occasions

• Many surgeons use a hybrid TKR with uncemented femoral implant

Historical First uncemented prostheses :1970 (diffusion after1980) After some years, literature pointed out complications related to

implant designs, poly wear, osteolysis, metallic debris.

– Cuckler JM et al. Clin Orthop 2003– Noble PC, Clin Orthop 2003– Reilly MA, Walker PS et al. Clin Orthop 1982– Wasielewski et al. Clin Orthop 1997

– Gill GS et al. Clin Orthop 1999 and J Bone Joint Surg 2001– Laskin RS. Clin Orthop 2001– Pavone V et al. Clin Orthop 2001– Callaghan et al. J Bone Joint Surg 2000

Cement vs cementless CEMENT, negative points :• Difficult to do a good cementation• Operative time increased • Microembolisms possible• Polymerization heating may lead to bone necrosis • Possible allergy • 2 additional layers • Difficult to remove the excessive cement in the back of the

knee• Cement debris can be included into poly • Frequent lucent line under the cemented plateaus• Bony stock decreased • Revisions more difficult

CEMENT, negative points :• Difficult to do a good cementation• Operative time increased • Microembolisms possible• Polymerization heating may lead to bone necrosis • Possible allergy • 2 additional interfaces • Difficult to remove the excessive cement in the back of the knee• Cement debris can be included into poly • Frequent lucent line under the cemented plateaus• Bony stock decreased • Revisions more difficult

CEMENTLESS, negative points :• Stability is mandatory for bony integration

• Difficult to obtain a good bioactive surface

• Shear and tension on uncemented tibial implant

• Uncemented TKR are more expensive !

• Metal-back is necessary

Onsten I, Norqvist A, Carlsson AS, Bejaskov J, Shott S. A J Bone Joint Surg 1998  Hydroxyapatite augmentation of the porous coating improves fixation of tibial component: a randomised RSA study in 116 patients

Witheside LA. Clin Orthop 2001Long-term followup of the bone-ingrowth Ortholoc Knee System without a metal-backed patella Hofmann AA. Hofmann AA, Evanich JD, Ferguson RP. Clin Orthop 2001 Ten to 14-year clinical followup of the cementless Natural Knee 300 TKR 10 yrs survival 95.1 %

Dixon P, Parish EN, Chan B, Chitnavis J, MJ Cross. J Bone Joint Surg 2003Hydrxyapatite-coated, cementles total knee replacement in patients aged 75 years and over

In favour of uncemented TKR ( f.up >10y)

Comparative studies : cemented vs uncemented

in favour of cemented implants

Lachiewicz PF. Cement versus cementless total knee replacement : is there a place for cementless fixation in 2001.Current opinion in orthopaedics 2000

RSA study : bony fixation more secure with cement. Some cementless design have good results. The main drawback: uncemented implants are too expensive!

McCaskie AW et al. Randomised, prospective study comparing cemented and cementless total knee replacement. Results of press-fit condylar knee replacement at five years, J Bone Joint Surg 1998 

Prospective randomised study on 139 TKR. At 5 years f.up frequent lucent lines with cement. BUT uncemented implant are too expensive!

Duffy GP et al. Cement versus cementless fixation in total knee arthroplasty. Clin Orthop 1998 

Prospective study of 55 Press fit condylar (PFC) vs 51cemented PFC . More revision in the uncemented group (patellar problems).Survival rate10 ys: 72 % vs 94 % Berger RA et al. Long term followup of the Miller-Galante total knee replacement. Clin Orthop 2001 172 cemented TKR « Miller-Galante I » vs 109 « Miller-Galante II » f.up 11ys. Survival rate 84% for MG I and 100% for MG II. Difference due to patellar problems of the MGI

Several studies confirm these data concerning patellar implant

Comparative studies : cemented vs uncemented

NO difference

Khaw FM et al. A randomised controlled trial of cemented vs cementless press-fit condylar total knee replacement. Ten year survival analysis.

J Bone Joint Surg 2002 277 cemented PFC vs 224 cementless : survival rate : 96,5 % - 96,6 % f.up 10 ys.

Bassett RW. Results of 1000 performance knees: cementless versus cemented fixation. J Arthroplasty 1998 584 cementless vs 416 cemented TKR f.up 5 ys (survival rate 99%) NO difference

Buechel FF et al. Twenty-year evaluation of meniscal bearing and rotating platform knee replacements. Clin Orthop 2001

373 LCS New Jersey (64 cemented, 104 cementless porocoat CR, 109 rotating). Survival rate : 97,7 % f.up 10 yrs and 20 yrs. NO difference for bony fixation.

Parker DA et al. Long-term followup of cementless versus hybrid fixation for total knee arthroplasty. Clin Orthop 2001

100 Miller-Galante I, with or without cement : NO difference after 12.8 ys

Still it is difficult to compare different TKR

• Shape, design are different• Fixation

– 1, 2, 3 or 4 pegs

– Cross shaped stem, short, long

– Cylindric stem, smooth or not

Walker PS et al. J Bone Joint Surg 1981 Study of 12 cemented tibial implants on cadaveric tibias

The best fixations were obtained with : - Full poly plateau - Monobloc metal-backed

implant (with one or two pegs)

The mechanical behaviour is variable according to the implant designs

With cementless implants, a cadaveric experiment is obviously Impossible!

Coating

Polyethylene Calcium Hydroxyapatite Titanium micro spheres

Titanium mesh CSTI TM

Polyethylene pegs (Freeman) Hydroxyapatite Porous metal (Hungerford) Micro spheres Titanium mesh (Miller-Galante) CSTi (Sulzer)

Cancellous bone

Pores : 4 - 500 microns

CSTiTM Interface Microstructure

CSTi TM (Natural – INNEX)

Pores : 4 - 500 microns

RSA studies : implant osteointegration and stability

- Fuiko Ret al. Osteointegration and implant position after cementless total knee replacement. Clin Orthop 2003

101 uncemented LCS New Jersey

- Onsten I et al. A Hydroxyapatite augmentation of the porous coating improves fixation of tibial component: a randomised RSA study in 116 patients. J Bone Joint Surg 1998

146 « Press fit condylar » (PFC) 49 cemented, 47 with porous coating and 50 porous+HAC : No difference

- Hofmann AA et al. 10 to 14-year clinical followup of the cementless Natural Knee System. Clin Orthop 2001s 176 Natural Knee with CSTI survival rate of 95% , f.up 10 ys.

• Witheside LA. Long-term followup of the bone-ingrowth Ortholoc Knee System without a metal-backed patella. Clin Orthop 2001

202 « Ortholoc porous coated » survival rate of 98.6% f.up 18 ys

 

Stability is quickly obtained

- if the bony cuts are correctly done

- if implants are in contact with the spongious bone

- and covering cortical bone

The post op rehabilitation is the same in the 2 groups

Cemented or cementless

Osteo integration of cementless implants

A Reality !Stable with time !

Fixation - osteointegration - wearFemur : In the literature femoral osteointegration is not a problem.

Tibial fixation is more controversial :

Osteolysis had been described (could be related to poly wear debris)

But osteointegration is successfull

Loosening should not be confused with fixation failure !

The results depend on many factors• Age• Weight• Osteoporosis• PCL Conservation or not• Patellar resurfacing or not• Polyethylene thickness • Quality of poly fixation on the tibial implant

Cemented «Total condylar»

– Brassard MF, Insall JN et al. Clin Orthop 2001– Gill GS et al. Clin Orthop 1999. J Bone Joint Surg 2001– Rodriguez JA, Bhende H, Ranawat C. Clin Orthop 2001– Pavone et al Clin Orthop 2001 120 TKR survival : 91% 23 yrs

Uncemented «LCS New-Jersey»– Buechel FF Sr, Buechel FF Jr, Pappas MJ, D’Alessio J. Twenty-year

evaluation of meniscal bearing and rotating platform knee replacements. Clin Orthop 2001

Similar survival rate

BUT tibial plateaus are different - « all poly » for Total condylar - Rotatory «metal-backed» for LCS

2 TKR are considered as gold standard each in its own categorie

Cement and « metal backed » (MB) tibia

In favour of cemented MB

Gill GS, Joshi HB. Long-term results of Kinematic condylar knee replacement: 404 « Kinematic » cemented CR . Survival rate: 92.6 % f.up 17 ys

Laskin RS. The Genesis Total knee System. A 10-year followup study. Clin Orthop 388, 95-102 2001 100 TKR cemented« Genesis » : Survival rate 97 % f.up 10 ys ( with or without PCL)

Lachiewicz PF. Cement versus cementless total knee replacement : is there a place for cementless fixation in 2001. Current opinion in orthopaedics 2001

In favour of cemented full poly

Rodriguez JA et al Total Condylar Knee Replacement. A 20-year followup study. ClinOrthop 2001

Brassard MF, Insall JN et al. Does modularity affect clinical success? A comparison with a minimum 10-year followup. Clin Orthop 2001; 388: 26-3274 TKR « Insall-Burnstein full Polyethylene » vs 82 TKR « Insall-Burnstein MB ». radio lucent line : 29%: MB , vs 11% full poly, but no clinical difference. Survival rate f.up 11 ys : 92,6 % and 98 %.

Drawbacks of the MB Implant fractures (never with recent TKA)

Noble et al. Clin Orthop 2003 Wear : cemented TKR : 35 %, non cemented TKR: 25 % .+ Impingements with cement fragments

Cuckler et al. Polyethylene damage on the nonarticular surface of modular total knee prostheses. Clin Orthop 2003

Polyethylene can be wear out along the non articular tibial surface with modular plateaus

Reilly, Walker et al . Effects of tibial component on load transfer in the upper tibia. Clin Orthop 1982

Drawbacks of the MB : Polyethylene wear

• Meding et al. Clin Orthop 2001 387 cemented TKR « AGC » Survival rate : 94.3 % f.up 10.7ys Comparison moulded 4.4 mm poly plateau on a 3.6 mm metallic plateau vs

10mm all poly plateau : NO difference.

• Ritter MA et al. Clin Orthop 2001 4583 TKR cemented « AGC » (except 348 cemented femurs) with PCL and

a moulded poly plateau on metal: survival rate 98.8% at 15 ys.

• Rand JA et al. J Bone Joint Surg 2003. F.up:10 ys Survival rate : 92 % for cemented non modular MB plateaus 90 % for cemented modular MB plateaus 97 % for cemented all poly plateaus

Studies proving the best behaviour of moulded or fixed poly plateaus

My personnal experience : 4399 arthroplasties

Cement : 1408 (THA + TKA)

Cementless : 2991

– knee : 1121– Hip : 1870

1121 uncemented knees (out of 1572)

• I almost never use cement for primary TKR

• I only use cement - In case of hinge TKR

- For some revisions - In case of large bony defects when a bone graft could delay the weight bearing

For my last 500 consecutive TKR, cement has still been used : - for 17 femurs ( 3.1 %) - for 70 tibias ( 15 %)

Other features of the series :

480 knees are CR (PCL) (96 %) Only 4 % of patella resurfaced

HAP

« Goëland »

CSTI TM

346 cases

775 cases

Natural

Innex

Personnal experience of cementless TKR

Survival rate : 94 %

f.up : 10 to 16 ys

Cementless shortens the procedure

when the bone cuts are good

The best cement is spongious bone under the implant before impaction

Revisions are easier in cementless cases

• The use of thin chisels can separate the implant from the bone, step by step, with a minimum damage to the adjacent bone

• It is not the case after cementation !

Preservation of the bone stock is an important issue for the future

• A new cementless implant is often still possible

• Or a cemented implant, but the use of standard TKR, as in primary cases, is possible

Case of revision of a cementless tibial implant

Rare case of osteolysis under the medial plateau

Removal of the implant

Explanted knees shown a good bony ingrowth

CSTI

Case of a cementless tibial implant : osteolysis with progressive subsidence 2-6 months p.o

Tilting, then stabilisation in this bad position.

Revision to correct flexion contracture

Difficulties to separate implants from bone !!

• Uncemented bio active surfaces are able to create an osteointegration even lately

• After subsidence the uncemented implants can found a new and stable position

In case of cemented TKR loosening is the only answer

Hofmann AA et al. Ten to 14-year clinical followup of the cementless

Natural Knee System. Clin Orthop 2001

I stil use cemented TKR

AXEL

Constrained TKR for :

Important articular damages

Ligamentous laxity

PCL

I stil use cemented TKR

With non constrained prostheses

Revision for a septic case (2 stages)

Uncemented femur

I stil use cemented TKR

Long stems

With non constrained prostheses

But revisions are possible with cementless TKR

500 recent primary TKR during the same time :

66 TKR were revised

21 uncemented femurs

24 uncemented tibias

Advantages to use uncemented TKR

• Uncemented femoral implant : no problem

• Uncemented tibial implant «metal backed » – Good osteointegration

– Bone stock preservation

– Revisions are easier

Metal back have many advantages :

– Modularity with a polyethylene plateau that can be changed without removing the tibial implant

– The poly wear is similar to the full poly plateau if it is thick enough and well fixed

– The possible use of a mobile bearing

ConclusionWhy do I use uncementd TKR ?

In primary cases, cementless or cemented TKA are similar

The question is rather : Why should I use cement when it is not necessary ?

Cement is usefull when the bony conditions are poor