- Email: [email protected]
Response to Letter to the Editor on “Patient Reported Kneeling Ability in Fixed and Mobile Bearing Knee Arthroplasty”
Accepted Manuscript “Patient Reported Kneeling Ability in Fixed and Mobile Bearing Knee Arthroplasty”: Our Concerns Dr Neil Artz, PhD, Mr Mo Hassaballa, MD, Mr James Robinson, MB BS MRCS FRCS(Orth) MS, Mr John Newman, FRCS, Mr Andrew Porteous, MBChB(UCT) DipPEC(SA) FRCS(Ed) MSc(Ortho Engin) FRCS(Tr & Ortho), Mr James Murray, MA FRCS (Tr and Orth) MB BChir (Cantab) PII:
S0883-5403(16)30933-0
DOI:
10.1016/j.arth.2016.12.047
Reference:
YARTH 55579
To appear in:
The Journal of Arthroplasty
Received Date: 27 October 2016 Accepted Date: 28 December 2016
Please cite this article as: Artz N, Hassaballa M, Robinson J, Newman J, Porteous A, Murray J, “Patient Reported Kneeling Ability in Fixed and Mobile Bearing Knee Arthroplasty”: Our Concerns, The Journal of Arthroplasty (2017), doi: 10.1016/j.arth.2016.12.047. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT PATIENT REPORTED KNEELING ABILITY IN FIXED AND MOBILE BEARING KNEE ARTHROPLASTY Dr Neil Artz PhD, Institute of Sport and Exercise Science, University of Worcester, Worcester, UK, WR2 6AJ
RI PT
Mr Mo Hassaballa MD, Bristol Knee Group, Avon Orthopaedic Centre, Southmead Hospital, Bristol, UK, BS10 5NB Mr James Robinson MB BS MRCS FRCS(Orth) MS, Bristol Knee Group, Avon Orthopaedic Centre, Southmead Hospital, Bristol, UK, BS10 5NB
SC
Mr John Newman FRCS, Bristol Knee Group, Avon Orthopaedic Centre, Southmead Hospital, Bristol, UK, BS10 5NB
M AN U
Mr Andrew Porteous MBChB(UCT) DipPEC(SA) FRCS(Ed) MSc(Ortho Engin) FRCS(Tr & Ortho), Bristol Knee Group, Avon Orthopaedic Centre, Southmead Hospital, Bristol, UK, BS10 5NB Mr James Murray MA FRCS (Tr and Orth) MB BChir (Cantab), Bristol Knee Group, Avon Orthopaedic Centre, Southmead Hospital, Bristol, UK, BS10 5NB Corresponding author: Dr Neil Artz
AC C
EP
TE D
Tel: +44 (0) 1905 542814 Email: [email protected]
ACCEPTED MANUSCRIPT “Patient Reported Kneeling Ability in Fixed and Mobile Bearing Knee Arthroplasty”: Our Concerns
Authors response: Dear Colleagues,
RI PT
Thank you for your letter regarding “Patient reported kneeling ability paper in fixed and mobile bearing knee arthroplasty”. We appreciate your comments on the article and the concerns raised.
SC
On the first point, from the inception of the study in 2000 our hypothesis was generated from the original concept that mobile-bearings prostheses were designed to enhance flexion of the knee and thus improve the ability of patients to perform high-flexion tasks such as kneeling. However, we acknowledge that since this time there has been a growing body of literature that indicates no differences in kinematic or functional outcomes are evident between the two bearing types and thus we accept that our hypothesis at time of publication should have reflected this.
AC C
EP
TE D
M AN U
Secondly, on reflection the phrase “the literature comparing these different designs is scarce” is inaccurate, we would like to note that the intention of the phrase was to highlight that there are few studies that have specifically compared and reported on high-flexion tasks, such as kneeling, between mobile and fixed bearing UKA and TKA. Lee [1] has provided an excellent biomechanical review of kneeling, and more recently White et al [2] has published patient reported factors influencing the ability to kneel on a cohort of 115 total knee arthroplasty patients with interesting results. The intention of our study was to add to the literature on kneeling after knee arthroplasty with specific focus on self reported outcome in mobile and fixed bearing prostheses as measured by question 7 of the Oxford Knee Score. Kim et al [3] reports on radiological and clinical outcomes (KSKS, KSFS and WOMAC) of 32 patients with LPS-Flex mobile and 34 patients with LPS-Flex fixed bearing prostheses with kneeling “assessed through interview or observation” at follow-up as stated in their methodology on page 26. Our study reports on self-reported kneeling ability (OKS7) from a cohort of 471 AMC Uniglide UKA and 206 Rotaglide+ TKA. In contrast to the results of Kim et al [3] our study shows that a significant proportion of patients in the fixed bearing Rotaglide+ group report that they are able to kneel at 1 and 2 years after surgery compared to the mobile bearing group. However, we acknowledge and that no further objective measures of kneeling ability or visual confirmation were recorded in our study, unlike that of Kim et al [3]. Finally, we have included baseline measures for Oxford Knee Score (OKS), WOMAC pain and function, and range of knee flexion for each of the Rotaglide+ mobile and fixed bearing groups (Table 1). No significant difference in baseline parameters were observed. Unfortunately, we are unable to provide patient weight measures to determine whether this impacts on kneeling ability and agree this is an important point to consider in future studies. WOMAC Knee flexion (0) function Fixed bearing 18.4 (7.0) 16.3 (3.1) 22.0 (4.8) 99.9 (16.7) Range (7-37) Range (8-25) Range (10-35) Range (60-140) Mobile bearing 18.0 (7.2) 15.7 (3.4) 22.2 (4.5) 100.8 (16.3) Range (5-40) Range (5-23) Range (10-34) Range (40-130) Table 1. Mean (SD) and range of baseline scores for Oxford Knee Score, WOMAC pain and function, and knee range of flexion in Rotaglide+ mobile and fixed bearing groups. Total OKS
WOMAC pain
ACCEPTED MANUSCRIPT In addition, we agree that further high quality longitudinal studies are required to investigate the impact of bearing type on high-flexion activities such as kneeling and we hope that our study provides some impetus for research in this area. We also would like to note that our study was conducted prior to OXFORD PAQ scoring system. Therefore we accept the potential ceiling effect of the Oxford knee score (OKS), but we look foreword to your future results when they are published.
Dr Neil Artz, Mr Mo Hassaballa, Mr James Murray and colleagues.
RI PT
Yours faithfully
AC C
EP
TE D
M AN U
SC
1. Lee T. Biomechanics of hyperflexion and kneeling before and after knee arthroplasty. Clin Orthop Surg 2014; 6(2):117-26. 2. White L, Stockwell T, Hartnell N, Hennessy M, Mullan J. Factors preventing kneeling in a group of pre-educated patients post total knee arthroplasty. J Orthop Traumatol 2016;17(4):333-338. 3. Kim TW, Park SH, Suh JT. Comparison of mobile-bearing and fixed-bearing designs in high flexion total knee arthroplasty: using a navigation system. Knee Surg Relat Res 2012;24(1):2533.
S0883-5403(16)30933-0
DOI:
10.1016/j.arth.2016.12.047
Reference:
YARTH 55579
To appear in:
The Journal of Arthroplasty
Received Date: 27 October 2016 Accepted Date: 28 December 2016
Please cite this article as: Artz N, Hassaballa M, Robinson J, Newman J, Porteous A, Murray J, “Patient Reported Kneeling Ability in Fixed and Mobile Bearing Knee Arthroplasty”: Our Concerns, The Journal of Arthroplasty (2017), doi: 10.1016/j.arth.2016.12.047. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT PATIENT REPORTED KNEELING ABILITY IN FIXED AND MOBILE BEARING KNEE ARTHROPLASTY Dr Neil Artz PhD, Institute of Sport and Exercise Science, University of Worcester, Worcester, UK, WR2 6AJ
RI PT
Mr Mo Hassaballa MD, Bristol Knee Group, Avon Orthopaedic Centre, Southmead Hospital, Bristol, UK, BS10 5NB Mr James Robinson MB BS MRCS FRCS(Orth) MS, Bristol Knee Group, Avon Orthopaedic Centre, Southmead Hospital, Bristol, UK, BS10 5NB
SC
Mr John Newman FRCS, Bristol Knee Group, Avon Orthopaedic Centre, Southmead Hospital, Bristol, UK, BS10 5NB
M AN U
Mr Andrew Porteous MBChB(UCT) DipPEC(SA) FRCS(Ed) MSc(Ortho Engin) FRCS(Tr & Ortho), Bristol Knee Group, Avon Orthopaedic Centre, Southmead Hospital, Bristol, UK, BS10 5NB Mr James Murray MA FRCS (Tr and Orth) MB BChir (Cantab), Bristol Knee Group, Avon Orthopaedic Centre, Southmead Hospital, Bristol, UK, BS10 5NB Corresponding author: Dr Neil Artz
AC C
EP
TE D
Tel: +44 (0) 1905 542814 Email: [email protected]
ACCEPTED MANUSCRIPT “Patient Reported Kneeling Ability in Fixed and Mobile Bearing Knee Arthroplasty”: Our Concerns
Authors response: Dear Colleagues,
RI PT
Thank you for your letter regarding “Patient reported kneeling ability paper in fixed and mobile bearing knee arthroplasty”. We appreciate your comments on the article and the concerns raised.
SC
On the first point, from the inception of the study in 2000 our hypothesis was generated from the original concept that mobile-bearings prostheses were designed to enhance flexion of the knee and thus improve the ability of patients to perform high-flexion tasks such as kneeling. However, we acknowledge that since this time there has been a growing body of literature that indicates no differences in kinematic or functional outcomes are evident between the two bearing types and thus we accept that our hypothesis at time of publication should have reflected this.
AC C
EP
TE D
M AN U
Secondly, on reflection the phrase “the literature comparing these different designs is scarce” is inaccurate, we would like to note that the intention of the phrase was to highlight that there are few studies that have specifically compared and reported on high-flexion tasks, such as kneeling, between mobile and fixed bearing UKA and TKA. Lee [1] has provided an excellent biomechanical review of kneeling, and more recently White et al [2] has published patient reported factors influencing the ability to kneel on a cohort of 115 total knee arthroplasty patients with interesting results. The intention of our study was to add to the literature on kneeling after knee arthroplasty with specific focus on self reported outcome in mobile and fixed bearing prostheses as measured by question 7 of the Oxford Knee Score. Kim et al [3] reports on radiological and clinical outcomes (KSKS, KSFS and WOMAC) of 32 patients with LPS-Flex mobile and 34 patients with LPS-Flex fixed bearing prostheses with kneeling “assessed through interview or observation” at follow-up as stated in their methodology on page 26. Our study reports on self-reported kneeling ability (OKS7) from a cohort of 471 AMC Uniglide UKA and 206 Rotaglide+ TKA. In contrast to the results of Kim et al [3] our study shows that a significant proportion of patients in the fixed bearing Rotaglide+ group report that they are able to kneel at 1 and 2 years after surgery compared to the mobile bearing group. However, we acknowledge and that no further objective measures of kneeling ability or visual confirmation were recorded in our study, unlike that of Kim et al [3]. Finally, we have included baseline measures for Oxford Knee Score (OKS), WOMAC pain and function, and range of knee flexion for each of the Rotaglide+ mobile and fixed bearing groups (Table 1). No significant difference in baseline parameters were observed. Unfortunately, we are unable to provide patient weight measures to determine whether this impacts on kneeling ability and agree this is an important point to consider in future studies. WOMAC Knee flexion (0) function Fixed bearing 18.4 (7.0) 16.3 (3.1) 22.0 (4.8) 99.9 (16.7) Range (7-37) Range (8-25) Range (10-35) Range (60-140) Mobile bearing 18.0 (7.2) 15.7 (3.4) 22.2 (4.5) 100.8 (16.3) Range (5-40) Range (5-23) Range (10-34) Range (40-130) Table 1. Mean (SD) and range of baseline scores for Oxford Knee Score, WOMAC pain and function, and knee range of flexion in Rotaglide+ mobile and fixed bearing groups. Total OKS
WOMAC pain
ACCEPTED MANUSCRIPT In addition, we agree that further high quality longitudinal studies are required to investigate the impact of bearing type on high-flexion activities such as kneeling and we hope that our study provides some impetus for research in this area. We also would like to note that our study was conducted prior to OXFORD PAQ scoring system. Therefore we accept the potential ceiling effect of the Oxford knee score (OKS), but we look foreword to your future results when they are published.
Dr Neil Artz, Mr Mo Hassaballa, Mr James Murray and colleagues.
RI PT
Yours faithfully
AC C
EP
TE D
M AN U
SC
1. Lee T. Biomechanics of hyperflexion and kneeling before and after knee arthroplasty. Clin Orthop Surg 2014; 6(2):117-26. 2. White L, Stockwell T, Hartnell N, Hennessy M, Mullan J. Factors preventing kneeling in a group of pre-educated patients post total knee arthroplasty. J Orthop Traumatol 2016;17(4):333-338. 3. Kim TW, Park SH, Suh JT. Comparison of mobile-bearing and fixed-bearing designs in high flexion total knee arthroplasty: using a navigation system. Knee Surg Relat Res 2012;24(1):2533.