zimmer studies powerpoint

39
Artificial Knee Studies Zimmerman Reed, PLLP

Upload: zimmerman-reed-pllp

Post on 12-Nov-2014

4.757 views

Category:

Health & Medicine


2 download

DESCRIPTION

 

TRANSCRIPT

Page 1: Zimmer studies powerpoint

Artificial Knee Studies

Zimmerman Reed, PLLP

Page 2: Zimmer studies powerpoint

NexGen CR Problems

NexGen LPS-Flex Problems

NexGen Standard v. NexGen High Flex

NexGen MIS Problems

Introduction

Page 3: Zimmer studies powerpoint

Problems with the NexGen CR Flex

Dr. Berger Study

Page 4: Zimmer studies powerpoint

Dr. Richard A. Berger◦ Assistant Professor, Rush University Medical Center ◦ Degree in mechanical engineering from MIT ◦ Revolutionized hip and knee replacement surgery by

developing a minimally invasive method of replacing knee joints

◦ Full Disclosure: currently being investigated by the DOJ

Dr. Craig Della Valle◦ Assistant Professor, Rush University Medical Center ◦ Board Certified - Orthopaedic Surgery◦ Awarded the Hip Society's Frank Stinchfield Award for his

research

New York Times – The “Berger Study” AuthorsNew York Times June 19, 2010

Page 5: Zimmer studies powerpoint

From 2002 to 2008 Dr. Berger was a consultant for Zimmer, training physicians on Zimmer’s Minimally Invasive Surgery (“MIS”) technique

In 2005, Dr. Berger implanted the NexGen CR-Flex Porous into 125 patients

Over the next year, Dr. Berger found his patients reported uncommon pain relating to their NexGen knee

Berger Study Background

Page 6: Zimmer studies powerpoint

In early 2006, Dr. Berger’s follow-up care revealed X-rays showing lines in some patients where the implant met the thigh bone, an indication that the device was loose and had not fused completely

Several of the loose kneeseventually required early knee revision surgery

Berger Study Background

Page 7: Zimmer studies powerpoint

As a result of the 2005-2006 experience, Dr. Berger, along with Dr. Della Valle, set up a study of 100 patients who received the NexGen CR-Flex Porous Knee

Berger Study

Page 8: Zimmer studies powerpoint

Dr. Berger’s and Dr. Della Valle’s presented their results at American Academy of Orthopaedic Surgeons Conference in March 2010

Failure rate resulting in revision surgery reached 9%

Actual number of complications could be much higher as many patients (36%) showed signs of loosening but had not yet reached the level of revision surgery

Berger’s Study Findings:

Page 9: Zimmer studies powerpoint

“This component is still commercially available but should not be used for

any patient.”  Dr. Richard A. Berger Rush Medical Center

Former Zimmer Consultant

Dr. Berger’s Conclusion:

Page 10: Zimmer studies powerpoint

Problems with the NexGen LPS Flex

Loosening

Page 11: Zimmer studies powerpoint

High incidence of loosening of the femoral component in legacy posterior stabilized-flex total knee replacement◦ H.S. Han, et al, Journal of Bone and Joint Surgery –

British Edition, Vol 89-B, No. 11, Nov. 2007- Korea Study Demographics:

◦ 47 patients◦ 72 knees ◦ 44 women and 3 men◦ All NexGen LPS-Flex - no standard LPS

Study Goal: Analysis of high-flexion design for evidence of aseptic loosening and related pain

Han Study (2007)

Page 12: Zimmer studies powerpoint

Patients did get better flexion then regular Total Knee Replacement (“TKR”) designed knees◦ 111-165 degrees of knee flexion in LPS-Flex knee◦ Versus 110-120 degree of flexion in general TKA

BUT aseptic loosening was found at a higher rate in the LPS-Flex than regular TKR knees

◦38% of the knees (27) were loose at mean follow-up of 32 months ◦21% of the knees (15) were revised

at mean of 23 months

Han Study (2007) Study Results

Page 13: Zimmer studies powerpoint

All loosening at femoral component which migrated into a position of increased flexion◦ (i.e. additional flexion emanated from the fact that the

knee was loose)

“Several [physicians] have expressed concern that relatively small gains in maximum knee flexion achieved by making changes in the design may substantially reduce the stability of the prosthesis and increase the stresses on the component.”

“[W]e have not previously experienced such a high rate of early loosening for any design of TKR.”

Han Study (2007) – Specific Findings

Page 14: Zimmer studies powerpoint

Are High Flexion Activities after High-Flex Total Knee Replacement Safe?◦ Kang, S., Journal of Bone and Joint Surgery, British

Edition, Vol 92-B, Issue SUPP_II, 322

Study Demographics:◦ 72 knees were implanted◦ All were NexGen LPS-Flex

Study Goal: Determine the factors contributing to the high rate of aseptic loosening in LPS-Flex knees

Kang Study (2008)

Page 15: Zimmer studies powerpoint

At a mean of 32 months, 27 cases (38%) had shown the radiological findings of aseptic loosening around the femoral components

At a mean of 32 months, 15 cases (21%) had been revised for the progression of component loosening and pain

Kang (2008) Results

Page 16: Zimmer studies powerpoint

Three- to six-year follow-up results after high-flexion total knee arthroplasty: can we allow passive deep knee bending?◦ Cho, SD et al., Journal of Bone and Joint Surgery - British

Volume, Vol 92-B, Issue SUPP_I, 131

Study Demographics:◦ 218 knees◦ All with NexGen LPS-Flex◦ 166 patients (22 males, 144 females)◦ Followed up for more than 3 years after TKA

Study Goals: Evaluate clinical and radiological follow up results of NexGen LPS-Flex

Cho Study (2010)

Page 17: Zimmer studies powerpoint

While NexGen LPS-flex Knee satisfactorily improved ROM, it was associated with a relatively high incidence of early loosening of the femoral components◦ Indications of loosening were visible on

radiographs of 30 knees (13.8%)◦ The mean time to loosening was 24 months◦ Eventually 7 knees required revision surgery

(3.2%)◦ The mean time to final revision surgery was 49

months

Cho Study (2010) Results

Page 18: Zimmer studies powerpoint

High Flex v. StandardFlexion and Range of Motion

Page 19: Zimmer studies powerpoint

Postoperative evaluation of the NexGen Legacy posterior stabilized LPS flex implants◦ Allen, DG, et al., La Societe Internationale de Chiragie

Orthopedic et de Traumalologic/La Societe Internationale de Recherche Orthopedic et de Traumalological, XXII World Congress, San Diego 2002:542

Study Goal: Compared range of motion between patients implanted with the LPS knee and the LPS-Flex knee

Found no difference between the two replacement knees in regards to range of motion

Allen Study (2002)

Page 20: Zimmer studies powerpoint

Range of motion of standard and high-flexion posterior stabilized total knee prostheses: a prospective randomized study◦ Kim, YH, et al., Journal of Bone and Joint Surgery, American

Edition, 2005; 87:1470-1475

Study Demographics:◦ 2 men◦ 48 women◦ Each received a standard LPS prosthesis in one knee and a LPS

high-flexion prosthesis in the other knee.

Study Goal: to compare the ranges of motion associated with standard and high-flexion posterior stabilized total knee prostheses in patients managed with simultaneous bilateral total knee arthroplasty

Kim Study (2005)

Page 21: Zimmer studies powerpoint

Authors found no difference between the eventual flexion of the two types of implanted knees

The knees with the standard LPS prosthesis had a mean range of motion of 135.8

The knees with the LPS-flex prosthesis had a mean range of motion of 138.6

Kim Study (2005) Results

Page 22: Zimmer studies powerpoint

High Flexion Knee Designs: More Hype than Hope? In the Affirmative◦ Ritter, M., Journal of Arthroplasty, 21(4), Supp. 1

(2006)

Study Demographics: ◦ 4727 Total Knee Replacements◦ Various ages and genders◦ Using Biomet knee

Study Goal: Evaluated the range of motion after 4727 TKA

Ritter Study (2006)

Page 23: Zimmer studies powerpoint

Range of motion after a TKA is dependant primarily upon preoperative range of motion; not device design

High-Flex designs may increase knee instability and possible wear

Ritter Study (2006) Conclusions

Page 24: Zimmer studies powerpoint

Range of flexion after primary TKA: the effect of soft tissue release and implant design.◦ Amed, I, et al., Orthopedics, 2009 Nov; 32(11):

811.

Study reported no difference in range of movement between standard and high flexion variants of the NexGen LPS implants in a randomized controlled study.

Amed Study (2009)

Page 25: Zimmer studies powerpoint

Clinical and radiological results of high flex total knee arthroplasty: a 5 year follow-up.◦ D. Wohlrab et al., Arch Orthop Trauma Surg (2009)

(Germany)

Study Demographics:◦ 30 patients received a LPS-Flex knee ◦ 30 received a LPS knee

Study Goal: Compare the clinical outcome and radiological results after TKR using a high flex design versus a standard design

Wohlrab Study (2009)

Page 26: Zimmer studies powerpoint

Flexion Measurement High Flex Knee Regular Knee

Post Op 108.5 ⁰ 105.67 ⁰

3 months 122.5 ⁰ 107.33 ⁰

3 years 112.14 ⁰ 109.14 ⁰

5 years 116.74 ⁰ 117.5 ⁰

Wohlrab Study (2009) Results

Limited to no advantage of using a high flex knee instead of a regular knee at the end of a 5 year period.

Page 27: Zimmer studies powerpoint

Comparison Between Standard and High-Flexion Posterior-Stabilized Rotating-Platform Mobile-Bearing Total Knee Arthroplasties◦ Choi, WC et al., Journal of Bone and Joint Surgery,

American Edition, 2010; 92:2634-42

Study Demographics:◦ 85 knee replacements using a standard prostheses design◦ 85 knee replacements using a high-flexion prostheses

design

Study Goal: Compare the outcomes of standard and high-flexion posterior stabilizing TKR

Choi Study (2010)

Page 28: Zimmer studies powerpoint

Showed no significant differences between standard and high flexion posterior stabilized mobile bearing total knee prostheses

Average maximal flexion for the standard design was 128⁰

Average maximal flexion for the high-flex design was 130⁰

Choi Study (2010) Results

Page 29: Zimmer studies powerpoint

Does the new generation of high-flex knee prostheses improve the post-operative range of movement?◦ Mehin, R., Journal of Bone and Joint Surgery, British

Edition, Vol. 92-B, Issue 10, 1429-1434

Study Type: Metadata analysis of already published articles regarding standard TKR design and high-flex TKR design

Study Goal: Determine whether the high-flex knee prostheses provide increased movement over standard knee prostheses design

Mehin Study (2010)

Page 30: Zimmer studies powerpoint

Analysis suggests that high-flex knee prostheses do not increase the post-operative maximum knee flexion compared with traditional implants

The weighted mean difference between the range of flexion between a standard design and a high-flex design was 2.1⁰

“Not only is [the difference] not statistically significant, but more importantly it is not clinically significant. Additional flexion of 2⁰

. . . has no functional advantage to the patient.”

Mehin Study (2010) Results

Page 31: Zimmer studies powerpoint

Comparison of standard and gender-specific posterior-cruciate-retaining high flexion total knee replacements: a prospective, randomized study ◦ Kim, YH, et al., Journal of Bone and Joint Surgery, British

Edition, 2010 May, 92(5): 639-45

Study Demographics:◦ 85 women◦ Received LPS-Flex design in one knee and gender-specific

LPS-Flex design in the other knee

Study Goal: Compare clinical and radiographic results in patients receiving a LPS-Flex or gender specific LPS-Flex prostheses

Kim Study (2010)

Page 32: Zimmer studies powerpoint

Study found no difference in clinical and radiological results in female patients undergoing standard and gender-specific variants of the NexGen LPS-Flex prosthesis

Kim Study (2010) Results

Page 33: Zimmer studies powerpoint

Problems with MIS Tibial

Loosening and Revision

Page 34: Zimmer studies powerpoint

Presented by Dr. Steven H Weeden and Dr. Steven Boyd Ogden◦ Podium Presentation: Early Loosening of MIS Tibial Implants

in Primary TKA

From 2005 to 2007 the authors performed 403 TKAs with a Zimmer MIS tibial component

Study Demographics:◦ All procedures were performed with a MIS technique, PS

articulation, and cement◦ 22 replacements did not have the modular stem component◦ 381 replacements included a stem component

American Academy of Orthopaedic Surgeons Conference in March 2010

Page 35: Zimmer studies powerpoint

The study reports a higher than expected rate of early loosening in cemented primary TKA with an MIS tibial component

The average time to diagnosis of loosening in this study is 2.6 yrs

The overall loosening rate was 5.2% (21 tibias of the 403)

Early Loosening of MIS Tibial Implants

Page 36: Zimmer studies powerpoint

Of the MIS Tibias placed without a stem component, 5 tibias out of 22 failed (24%)

Of the MIS tibias placed with a stem component, 16 tibias out of 381 failed (4.2%)

Early Loosening of MIS Tibial Implants specifics

Page 37: Zimmer studies powerpoint

The doctors recommendation: “the use of an MIS tibia without the use of a modular stem is not recommended secondary to a high rate of early loosening in primary TKA.”

Early Loosening of MIS Tibial Implants continued

Page 38: Zimmer studies powerpoint

Early Aseptic Loosening with Precoated Low Profile Tibial Component: A Case Study◦ Foran, J.R.H., et al, Journal of Arthroplasty, published online January 14,

2011

Authors performed TKAs in 460 patients using the NexGen MIS Tibial Component

Authors experienced early loosening of the tibial component◦ The average time to diagnosis of loosening was 17 months

In addition, several additional patients show radiographic signs of pending failure

Foran Case Study

Page 39: Zimmer studies powerpoint

Based on their experience with early aseptic loosening of the MIS Tibial Component, the authors report they will discontinue further use until the etiology of the high failure rate is able to be determined

Foran Case Study: Specific conclusions