Quadriceps Snip in 321 Revision Total Knee Arthroplasties: A Safe Technique in a Matched Cohort Study

Accepted Manuscript Quadriceps Snip in 321 Revision Total Knee Arthroplasties: A Safe Technique in a Matched Cohort Study Matthew P. Abdel, M.D, Anthony Viste, M.D., Ph.D, Christopher G. Salib, M.D, Daniel J. Berry, M.D PII:

S0883-5403(19)30672-2

DOI:

https://doi.org/10.1016/j.arth.2019.07.017

Reference:

YARTH 57409

To appear in:

The Journal of Arthroplasty

Received Date: 23 April 2019 Revised Date:

6 June 2019

Accepted Date: 11 July 2019

Please cite this article as: Abdel MP, Viste A, Salib CG, Berry DJ, Quadriceps Snip in 321 Revision Total Knee Arthroplasties: A Safe Technique in a Matched Cohort Study, The Journal of Arthroplasty (2019), doi: https://doi.org/10.1016/j.arth.2019.07.017. 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.

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Quadriceps Snip in 321 Revision Total Knee Arthroplasties: A Safe Technique in a

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Matched Cohort Study

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ABSTRACT

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Background: Quadriceps snips (QSs) are commonly used to gain enhanced exposure during

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revision total knee arthroplasty (TKAs). The goals of this study were to evaluate the longer-term

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clinical outcomes and complications in a contemporary cohort of patients treated with QS and to

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compare them to a matched cohort treated with standard exposure during revision TKAs.

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Methods: We retrospectively identified 3107 revision TKAs performed at our institution

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between 2002 and 2012. QS was performed in 321 of these knees. Each QS revision TKA was

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1:1 matched to a control (standard exposure) based on age, sex, BMI, surgery date, and reason

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for revision. Clinical outcomes studied included Knee Society score (KSS), range of motion

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(ROM), and extensor lag. Other outcomes assessed were complications (especially extensor

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mechanism disruption) and survivorship. Mean follow-up was 5 years.

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Results: The mean KSS improvement was not significantly different between groups (p=0.9).

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At latest follow-up, the mean ROM was 93° in the QS group and was slightly higher at 100° in

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the control group (p=0.002). Postoperative extensor lag of 10 degrees or more was present in 21

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(6.7%) QS knees vs 19 (6.8%) control knees (p=0.95). Complication rates were similar in both

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groups with extensor mechanism disruption occurring in 3 in the QS group (0.7% at 10 years) vs

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4 in the control group (0.8% at 10 years; p=0.91). Kaplan-Meier survivorships free of revision

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for aseptic loosening, free of any revision, and free of any reoperation were similar at 10 years

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(85%, 71%, and 61%, respectively, in the QS group vs 89%, 70% and 60%, respectively, in the

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control group).

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Conclusion: This matched cohort study is the largest to report the results of QS and also the

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largest to report results compared to patients treated with standard exposure. Building on the

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results of smaller historical series, this study demonstrates QS was a facile technique in complex

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revision TKAs allowing for safe exposure with few complications.

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Level of Evidence: III (Case-Control Study)

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Keywords: Quadriceps snip; revision total knee arthroplasty (TKA); exposure; extensor lag;

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extensor mechanism disruption

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INTRODUCTION

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The number of revision total knee arthroplasties (TKAs) continues to rise due to the growing

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utilization and prevalence of primary TKAs [1, 2]. Revision TKAs are challenging in part due to

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difficulties in obtaining adequate exposure, especially in patients with stiff knees and obese

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patients, who are among those most likely to require revision procedures [3, 4]. The main

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anatomic barrier to obtaining adequate exposure often is the extensor mechanism [5]. The goal

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of most extensile knee exposures is to facilitate exposure while simultaneously mitigating risk of

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extensor mechanism disruption given the known catastrophic outcomes and poor function

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associated with that complication [6, 7].

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In revision TKAs, surgical exposure should be carried out in a stepwise manner [5]. Typically,

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exposure begins with a standard medial parapatellar arthrotomy similar to primary TKA. Next,

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medial and lateral gutters are developed, removing any adhesive bands [1]. Thereafter, a wide

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medial release around the tibia is completed directly on bone, ensuring that the medial collateral

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ligament (MCL) is maintained in continuity. If the exposure remains limited, three main

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extensile exposures can then be utilized: quadriceps snip (QS), tibial tubercle osteotomy (TTO),

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and V-Y quadricepsplasty [8]. In modern practice, QS is considered the preferred option by

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many given its technical ease, lack of need to greatly modify the postoperative rehabilitation

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regimen, and apparent minimal morbidity compared to other techniques [1, 3, 9]. It was first

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described in 1995 by John Insall, MD [3] to allow for immediate postoperative knee mobilization

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without the extensor lags frequently seen with the previous Coonse-Adams VY turndown

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technique [10]. However, despite being widely used, there are very limited reported results of

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the QS technique, and larger series with longer-term follow-up utilizing this technique are not

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available.

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The aims of the current study were to compare the clinical outcomes (with specific emphasis on

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Knee Society scores (KSS), range of motion (ROM), and extensor lag), complications (with

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specific emphasis on extensor mechanism disruption), and long-term implant survivorship

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between revision TKAs with QS compared to a control group of revision TKAs treated without

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an extensile operative approach.

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PATIENTS AND METHODS

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We retrospectively identified 3107 revision or reimplantation TKAs completed between 2002

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and 2012 at a single academic institution using our total joint registry that follows patients at 1

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year, 2 years, 5 years, and every 5 years thereafter. Among these, 321 knees were treated with

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QSs (10%) at the time of revision or reimplantation TKA.

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Each case in the QS group was matched to a control revision or reimplantation TKA where

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exposure with standard medial parapatellar arthrotomy with medial and lateral gutter clearance

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and medial release around the tibia (control group) was utilized during revision TKA. Matching

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was based on age (±5 years), sex, BMI (±5 kg/m2), date of surgery (±1 year), and reason for

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revision (aseptic loosening, two-stage revision/reimplantation for periprosthetic infection or

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other causes). The entire study cohort included 642 revision TKAs with 321 revision TKAs

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exposed with a QS and 321 revision TKAs exposed with a medial parapatellar arthrotomy

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(Appendix Figure 1). Institutional review board (IRB) approval was obtained prior to initiation

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of the study.

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Study inclusion criteria were patients over 18 years of age at the time of revision TKA performed

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between 2002 and 2012. Indications for a QS in revision TKA typically followed an algorithmic

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approach in which the operative surgeon first performed a standard medial parapatellar

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arthrotomy, release of soft tissues from the proximal medial tibia, clearance of both medial and

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lateral femoral gutters, and polyethylene removal if appropriate. If the surgeon was still unable

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to gain satisfactory exposure, without undue extensor mechanism tension, by lateral patellar

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subluxation, then the QS usually was performed. All demographic data were retrieved from

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medical records. Extensor lag was defined as the difference between passive and active

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extension. Clinical outcomes were assessed using the Knee Society scoring system [11], degree

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of extensor lag, and ROM (excluding preoperative ROM for PJI patients due to poor accuracy of

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measurements before the second stage procedure, reflecting the stiffness encountered after

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immobilization--usually with static antibiotic loaded spacers--prior to the second stage

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procedure). All complications, revisions, and reoperations were recorded.

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The mean age at revision TKA in the QS group was 66 years (range, 24 – 92 years), mean BMI

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was 33 kg/m2 (range, 17 - 64 kg/m2), and 52% of the patients were males. The reason for

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revision in the QS group was PJI as part of a two-stage exchange arthroplasty in 46% of revision

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TKAs (note some of the two-stage patients also had a QS at the time of the first-stage implant

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removal procedure), aseptic loosening in 41%, and other in 13%. The mean age at revision TKA

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in the standard approach (control) group was 67 years (range, 29 – 88 years), mean BMI was 33

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kg/m2 (range, 18 – 55 kg/m2), and 52% were male. The reason for revision in the control group

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was PJI as part of a two-stage exchange arthroplasty at the time of re-implant in 46% of revision

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TKAs, aseptic loosening in 41%, and other for 13% (Table 1).

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Of the 321 revision TKAs in the QS group, 47 had died by most recent follow-up, with six dead

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within the first two years. Fifty-three were re-revised or had implants removed, with 30 re-

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revisions or implant removals performed within the first two years of their QS revision TKA.

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The remaining 221 QSs were alive and unrevised at most recent follow-up, with 210 (95%) with

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at least two years of follow-up. Mean follow-up for the QS group was 5.4 years (range, 2 – 14

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years). Of the 321 revision TKAs in the control group, 58 had died by most recent follow-up

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with six dead within the first two years. Sixty-five were re-revised or had implants removed,

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with 37 re-revisions or implant removals performed within the first two years of their initial

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revision TKA. The remaining 198 controls were alive and unrevised at most recent follow-up,

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with 181 (91%) with at least two years of follow-up. Mean follow- up was 5.3 years (range, 2 –

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13 years).

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Surgical Technique

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All quadriceps snips were performed as a lateral oblique (45°) extension of the upper part of the

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medial parapatellar arthrotomy, usually 10-15 cm above the superior pole of the patella (Figures

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1A-C) if completed at the beginning of the exposure. Alternatively, if the surgeon decided to

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perform the quadriceps snip after an initial standard length medial parapatellar arthrotomy

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proved to provide inadequate exposure, then it was completed 10-15 cm above the patella as a

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supplemental oblique division of the quadriceps tendon (Figure 2). The QS went from distal to

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proximal obliquely into the quadriceps tendon towards the vastus lateralis muscle, parallel to its

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inferior and oblique aspect (Figure 1A). Caution was taken to incise the tendon below the

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musculotendinous junction of the rectus femoris muscle to facilitate a strong repair, but far

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enough proximal to the patella to provide a long surface area for robust side-to-side quadriceps

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tendon [9]. The patella was subluxated laterally or everted gaining enhanced exposure (Figure

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1B). At the end of the procedure, the extensor mechanism was repaired with multiple side-to-

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side sutures along the main arthrotomy above the patella, and typically with non-absorbable

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figure of 8 sutures in the QS portion of the exposure (Figure 1C). The technique was similar for

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aseptic revision TKAs such as those for arthrofibrosis (Figures 3A-D), and previously infected

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revision TKAs at the time of reimplantation during a two-stage exchange protocol (Figures 4A-

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C).

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The rehabilitation protocol was similar for both groups and included immediate partial or full

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weight-bearing (depending on the bone reconstruction) with unrestricted ROM exercises.

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Quadriceps strengthening exercises were typically delayed until 8 weeks postoperatively.

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Statistical Methods

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The data are reported using summary statistics such as mean for continuous variables and count

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(percentage) for categorical variables. The analysis compared the QS group to the control group.

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The primary outcomes were Knee Society pain and function scores, ROM, extensor lag, extensor

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mechanism disruption as a complication, and survivorship free of aseptic loosening, any

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revision, and any reoperation. Range of motion and the KSS measurements were compared

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between the two groups using generalized linear models utilizing generalized estimating

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equations (GEE) to account for the within-subject correlation due to patients with both knees

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included.

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Survival analysis was performed using the Kaplan-Meier method [12] and Cox proportional

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hazards regression for the following time-to-event outcomes: revision for aseptic loosening, any

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revision (or implant removal), and any reoperation. The Cox models used the robust variance

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estimate to account for the within-subject correlation due to patients with bilateral knee

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involvement. Statistical significance was set at a p-value ≤ 0.05. All analyses were conducted

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using SAS version 9.4 (SAS Institute Inc., Cary, NC) and R version 3.1.1 (R Core Team, R

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Foundation for Statistical Computing, Vienna, Austria, 2014).

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RESULTS

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Knee Society Scores, Range of Motion, Extensor Lag, and Extensor Mechanism Disruption

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The mean KSS showed no difference at most recent follow-up between the two groups (76 vs.

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76; p=0.9) (Table 2). Flexion and ROM were significantly lower in the QS group than the

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control group before the revision procedure (flexion: 89° vs 102°, p<0.001; ROM: 85° vs 100°,

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p<0.001, respectively) and at most recent follow-up (flexion: 94° vs 102°, p<0.001; ROM: 93°

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vs 100°, p <0.001, respectively). There was no significant difference between the QS and

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control groups in regards to post-revision flexion contracture (1.5° vs 1.3°, respectively; p=0.84).

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Prevalence of postoperative extensor lag of 10 degrees or greater was not significantly different

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between the two groups (QS: 6.7% vs control: 6.8%; p=0.92). A previous history of extensor

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mechanism disruption was noted in 1 QS knee and 1 control knee (p=0.99). Postoperative

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extensor mechanism disruptions occurred in 3 QS knees and 4 control knees (hazard ratio [HR]:

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0.9; 95% CI: 0.1-6.9; p=0.91), and none were through the tendon where the quadriceps snip was

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performed.

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Survivorship

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The 10-year Kaplan-Meier survivorship free of revision for aseptic loosening was 85% (95% CI:

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77-95%) for the QS group vs. 89% (95% CI: 82-96%) for the control group (Figure 5). The 10-

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year Kaplan-Meier survivorship free of any revision or implant removal was 71% (95% CI: 61-

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82%) for the QS group vs. 70% (95% CI: 62-78%) for the control group (Figure 6). The 10-year

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Kaplan-Meier survivorship free of any reoperation was 61% (95% CI: 52-72%) for the QS group

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vs. 60% (95% CI: 53-69%) for the control group (Figure 7). There were no significant

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differences between the QS group and the control group in terms of any Kaplan-Meier

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survivorships.

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There was no significant difference between the QS group and the control group in terms of

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complications (HR: 0.8, 95% CI: 0.6-1.1, p=0.23) (Table 3).

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DISCUSSION

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Quadriceps snip is a reliable option for enhancing exposure during revision TKA, providing

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comparable results to revision TKA performed with a standard medial parapatellar arthrotomy

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and surgical exposure (Table 4). Our series of 321 revision TKAs exposed with a QS

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demonstrated that when compared to a control group, there was no difference in postoperative

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extensor lag, catastrophic complications of extensor mechanism disruptions, or implant

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survivorship. Additional advantages to the QS include its technical ease, and similar

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postoperative rehabilitation protocol to the standard surgical approach (despite some surgeons

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instructing patients to avoid active quadriceps strengthening for 8 weeks postoperatively). All

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these factors render the QS an excellent exposure technique in difficult revision TKAs.

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In our series, 6.7% of patients in the QS group developed a new extensor lag of 10 degrees or

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more; this was very similar to the control group and may not be directly related to the QS. This

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may be due to the high proportion of these patients belonging to a two-stage exchange

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arthroplasty protocol for PJI. This complication was also noted by Bruni et al [13] who reported

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postoperative extensor lag in 45% of patients after QS in a small series (n=19/42) during

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reimplantation for PJI. For our study, patients who underwent a two-stage exchange arthroplasty

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for PJI had a mean 45-day resection interval before reimplantation with an antibiotic

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impregnated static spacer. Barrack et al [14] noted that QS showed no discernible disadvantage

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with regard to postoperative extensor lags or KSS when compared to standard exposure in

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TKAs.

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Importantly, there were an equal (and small) number of post-operative extensor mechanism

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disruptions in the QS and control groups. Bruni et al [13] and Sun et al [15] reported no

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disruptions in their respective series, albeit with limited patient sample sizes. The low rate of

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extensor mechanism disruptions suggests the QS is associated with a high and reliable rate of

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quadriceps tendon healing.

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Our series demonstrated KSS improvement from 44 to 76 in the QS group. This finding is also

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confirmed by similar reported rates of improvement in the literature [3, 14-16].

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The mean preoperative and post-operative knee flexion was less in the QS than the control

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group, as would be expected, due to the indications for use of the QS such as stiff knees that

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presented exposure challenges [14-16]. The mean post-operative ROM increased slightly in the

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QS group compared to preoperatively, while it remained unchanged from preoperative in the

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control group. At most recent follow-up, the mean ROM was 93° in the QS group in this study.

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A small series by Garvin et al [3] studying QS outcomes included 16 revisions and primary

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TKAs and demonstrated a mean 30° improvement of ROM. Although that series showed

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favorable clinical outcomes, QS is indicated as an exposure technique, not a release technique for

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increasing postoperative ROM. Our study findings are consistent with a series by Sun et al [15]

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who reported a final ROM of 96° after QS, and another series by Meek et al [16] who reported a

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mean preoperative ROM of 80° which improved to 95° postoperatively.

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Survivorship rates free of any revision or implant removal for any reason were similar between

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the two groups (61% vs 60%) at 10 years. Many of the failures in both groups were reinfections

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in the two-stage PJI group. Survivorship free of aseptic loosening was 85% in QS vs 89% in

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standard exposure at 10 years, consistent with reported rates [17]. Lackey et al [17] reported a

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93% survivorship free of aseptic loosening at 7 years in 297 revision TKAs. Similarly, Mabry et

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al [18] reported 92% survivorship free of aseptic loosening at 10 years in aseptic revision TKAs.

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Gudnason et al [19] had 65% of survivorship free of any revision at 10 years with a rotating-

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hinge construct in revision TKAs. Our survivorship rate was likely worsened by the inclusion of

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revision TKAs for PJI, a cohort associated with a higher risk of reoperation and revision.

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Revision TKA for infection has already been documented as a significant risk factor for

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decreased survivorship free of any revision (64% at 10 years [20]).

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There certainly are limitations to this study. We acknowledge the retrospective nature of this

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study. Patients had heterogenous indications for their revision TKAs which may affect the

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studied outcomes, however the matching process did include indication for operation. The

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decision to proceed with quadriceps snip was made intraoperatively at the discretion of the

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operating surgeon, and may hold subjective bias. The strengths of this study, however, include

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the mid and longer-term followup of a relatively contemporary large patient cohort included in

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the QS group and the matched cohort of patients treated with standard exposure.

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This matched cohort study is the largest series to date reporting the results of QS and comparing

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QS to the standard surgical exposure in revision TKAs. We found similar complication rates of

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postoperative extensor lag, extensor mechanism disruptions, and implant survivorship in the case

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and control groups. One may hypothesize that the rate of complications, including extensor

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mechanism problems, would have been higher in the QS group if an extensile exposure not been

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chosen in these challenging cases. In conclusion, the quadriceps snip was demonstrated to be a

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useful technique in difficult, selected revision TKAs allowing for a safe surgical exposure with

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few complications and was associated with a similar implant survivorship compared to standard

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medial parapatellar arthrotomy exposure. These data suggest that when the surgeon finds routine

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exposure inadequate during a revision TKA, QS may be performed with no identifiable penalty

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in risk of complications or procedure outcome.

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REFERENCES

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1. Abdel MP, Della Valle CJ. The surgical approach for revision total knee arthroplasty. Bone

262

Joint J 98-B(1 Suppl A): 113-115, 2016

263

2. Maradit Kremers H, Larson DR, Crowson CS, Kremers WK, Washington RE, Steiner CA,

264

Jiranek WA, Berry DJ. Prevalence of Total Hip and Knee Replacement in the United States. J

265

Bone Joint Surg Am 97(17): 1386-1397, 2015

266

3. Garvin KL, Scuderi G, Insall JN. Evolution of the quadriceps snip. Clin Orthop Relat Res

267

(321): 131-137, 1995

268

4. Odum SM, Van Doren BA, Springer BD. National Obesity Trends in Revision Total Knee

269

Arthroplasty. J Arthroplasty, 2016

270

5. Della Valle CJ, Berger RA, Rosenberg AG. Surgical exposures in revision total knee

271

arthroplasty. Clin Orthop Relat Res 446: 59-68, 2006

272

6. Bates MD, Springer BD. Extensor mechanism disruption after total knee arthroplasty. J Am

273

Acad Orthop Surg 23(2): 95-106, 2015

274

7. Schoderbek RJ, Jr., Brown TE, Mulhall KJ, Mounasamy V, Iorio R, Krackow KA, Macaulay

275

W, Saleh KJ. Extensor mechanism disruption after total knee arthroplasty. Clin Orthop Relat Res

276

446: 176-185, 2006

277

8. Younger AS, Duncan CP, Masri BA. Surgical exposures in revision total knee arthroplasty. J

278

Am Acad Orthop Surg 6(1): 55-64, 1998

279

9. Jacofsky DJ, Della Valle CJ, Meneghini RM, Sporer SM, Cercek RM. Revision total knee

280

arthroplasty: what the practicing orthopaedic surgeon needs to know. J Bone Joint Surg Am

281

92(5): 1282-1292, 2010

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EP

TE D

M AN U

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RI PT

260

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10. Coonse GK, Adams JD. A new operative approach to the knee joint. Surg Gynecol Obstet

283

77: 344-347, 1943

284

11. Insall JN, Dorr LD, Scott RD, Scott WN. Rationale of the Knee Society clinical rating

285

system. Clin Orthop Relat Res (248): 13-14, 1989

286

12. Kaplan E, Meier P. Non-parametric estimation from incomplete observations. J Am Stat

287

Assoc 53: 457-481, 1958

288

13. Bruni D, Iacono F, Sharma B, Zaffagnini S, Marcacci M. Tibial tubercle osteotomy or

289

quadriceps snip in two-stage revision for prosthetic knee infection? A randomized prospective

290

study. Clin Orthop Relat Res 471(4): 1305-1318, 2013

291

14. Barrack RL, Smith P, Munn B, Engh G, Rorabeck C. The Ranawat Award. Comparison of

292

surgical approaches in total knee arthroplasty. Clin Orthop Relat Res (356): 16-21, 1998

293

15. Sun Z, Patil A, Song EK, Kim HT, Seon JK. Comparison of quadriceps snip and tibial

294

tubercle osteotomy in revision for infected total knee arthroplasty. Int Orthop 39(5): 879-885,

295

2015

296

16. Meek RM, Greidanus NV, McGraw RW, Masri BA. The extensile rectus snip exposure in

297

revision of total knee arthroplasty. J Bone Joint Surg Br 85(8): 1120-1122, 2003

298

17. Lackey WG, Ritter MA, Berend ME, Malinzak RA, Faris PM, Meding JB. Midterm Results

299

of the Vanguard SSK Revision Total Knee Arthroplasty System. Orthopedics: 1-5, 2016

300

18. Mabry TM, Vessely MB, Schleck CD, Harmsen WS, Berry DJ. Revision total knee

301

arthroplasty with modular cemented stems: long-term follow-up. J Arthroplasty 22(6 Suppl 2):

302

100-105, 2007

AC C

EP

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282

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19. Gudnason A, Milbrink J, Hailer NP. Implant survival and outcome after rotating-hinge total

304

knee revision arthroplasty: a minimum 6-year follow-up. Arch Orthop Trauma Surg 131(11):

305

1601-1607, 2011

306

20. Wilke BK, Wagner ER, Trousdale RT. Long-term survival of semi-constrained total knee

307

arthroplasty for revision surgery. J Arthroplasty 29(5): 1005-1008, 2014

RI PT

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