The Knee 22 (2015) 95–99
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The Knee
Effect of body mass index and osteoarthritis on outcomes following arthroscopic meniscectomy: A prospective nationwide study O. Bailey a,⁎, K. Gronkowski b, W.J. Leach a a b
Western Infirmary Glasgow, United Kingdom National Services Scotland, United Kingdom
a r t i c l e
i n f o
Article history: Received 18 June 2014 Received in revised form 6 December 2014 Accepted 17 December 2014 Keywords: Knee Arthroscopy Meniscectomy Body mass index Arthritis
a b s t r a c t Background: Current evidence suggests limiting arthroscopic meniscectomy to those patients with no or early arthritis however outcomes of arthroscopic meniscectomy with patients of a higher body mass index (BMI) are not as widely available. The aim of this study was to determine if patient reported outcome scores for arthroscopic meniscectomy are adversely affected by the degree of knee osteoarthritis or patient BMI. Methods: All patients who underwent arthroscopic meniscectomy within the NHS in Scotland between the 6th of February and 29th of April 2012 were audited as part of the Scottish Government Musculoskeletal Audit and were eligible for inclusion within this study. A total of 270 patients returned both their pre-operative and post-operative EuroQol 5Q5D5L descriptive questionnaire and Knee injury and Osteoarthritis Outcomes Scores. Patients were stratified according to BMI, degree of osteoarthritis, history of injury, and duration of knee symptoms. Results: Pre-operative to post-operative EuroQol index scores [0.642 ± 0.253 to 0.735 ± 0.277, median ± SD] and Knee injury and Osteoarthrtis Outcome Scores [44.63 ± 18.78 to 62.28 ± 24.94, median ± SD] improved across all patients (p b 0.0001). This was irrespective of degree of BMI, history of injury, or duration of symptoms. There was no such improvement in patients with moderate to severe osteoarthritis. Those patients with a BMI N35 kg/m2 had lower post-operative scores than the pre-operative scores of those of BMI b30 kg/m2. Conclusions: Arthroscopic meniscectomy is beneficial regardless of patient BMI, duration of symptoms, history of injury, or in the presence of early osteoarthritis. © 2014 Elsevier B.V. All rights reserved.
1. Introduction Arthroscopic knee surgery with or without meniscectomy is one of the most common elective orthopaedic operations carried out today. Current guidance from the National Institute for Health and Clinical Excellence (NICE) on treatment of patients with osteoarthritis suggests limiting meniscectomy to those patients who either have no preoperative osteoarthritis or in those with osteoarthritis that is in the early stage only, unless there is evidence of mechanical locking or intra-articular loose bodies [1]. Guidance from the Osteoarthritis Research Society International (OARSI) suggests that benefit from meniscectomy in an arthritic knee has limited evidence at best [2], and the most recent American Academy of Orthopaedic Surgeons (AAOS) guidance cannot recommend for or against meniscectomy in patients with a primary diagnosis of osteoarthritis [3]. In the recent Scottish Government Knee Arthroscopy Audit and Patient Reported
⁎ Corresponding author at: Specialty Registrar Trauma & Orthopaedics, Western Infirmary Glasgow, Dumbarton Road, Glasgow G11 6NT, United Kingdom. Tel.: +44 141 211 2000. E-mail address: [email protected] (O. Bailey).
http://dx.doi.org/10.1016/j.knee.2014.12.008 0968-0160/© 2014 Elsevier B.V. All rights reserved.
Outcome Measures Project 2012 [4,5] 5% of knee arthroscopies were performed on patients with moderate to severe osteoarthritis. As part of this national audit into arthroscopic knee practices within the Scottish National Health Service (NHS) we present 6-month postoperative patient reported outcomes of those patients who underwent elective knee arthroscopic meniscectomy. Our null hypothesis was that there would be no difference in patient reported outcomes when taking into account the effect of BMI or osteoarthritis after a knee arthroscopy.
2. Methods All patients who underwent arthroscopic meniscectomy within the NHS in Scotland between the 6th of February and 29th of April 2012 were audited as part of the Scottish Government Musculoskeletal Knee Arthroscopy Audit [4,5] and were eligible for inclusion within this study. All patients were sent both pre-operative and 6-month post-operative questionnaire based assessments. Patients were fully informed and consent to analyse their data was assumed to be given at the time of completing each questionnaire. Study ethical approval was obtained through the National Services Scotland (PAC Ref 67/11).
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Each pre-operative and 6-month post-operative assessment was a combination of both the EuroQol 5Q5D5L [6,7] descriptive questionnaire, to assess the general health status of the patient (questions on Mobility, Self-care, Usual Activities, Pain/Discomfort, Anxiety/Depression), and the Knee injury and Osteoarthritis Outcome Score (KOOS) [8], to assess knee specific patient reported outcome measures (questions on Symptoms, Pain, Activities of Daily Living, Sport, Quality of Life). Both the EuroQol and KOOS questionnaires have been fully validated for use in both primary injury and osteoarthritis of the knee [6–8]. In addition to the EuroQol and KOOS outcome scores the following data on each patient was obtained: age (years), BMI (kg/m2), osteoarthritis severity (grade assigned by operating surgeon using preoperative radiographs or MRI and confirmed intra-operative by direct observation. Graded as none, early, moderate, advanced), gender, knee pain duration (months), and history of preceding knee injury. Data collection and analysis were undertaken by local audit coordinators and independent statisticians. Data was collated and analysed using Excel (Microsoft, USA) and SPSS (IBM Corporation, USA). Averages are presented as means or medians ± standard deviation. Normality was assessed using the Shapiro–Wilk Test. Parametric variables were analysed with 2-sample t-tests and non-parametric variables with a 2-tailed Mann–Whitney test for independent samples and a Wilcoxon Signed-Rank test for paired samples. A 2-tailed alpha value of b 0.05 was deemed as statistical significance. 3. Results One thousand five hundred and forty seven patients underwent planned elective knee arthroscopy within the NHS in Scotland between the 6th of February 2012 and 29th of April 2012. A total of 387 patients returned both pre-operative and post-operative questionnaires. Once linked to audit data a total of 367 patients had useable data, of which 270 patients underwent arthroscopic meniscectomy and were analysed accordingly. Table 1 provides a brief descriptive summary of the data. Median post-operative EuroQol index scores significantly improved compared to preoperative scores across all patients [Table 2]. Subgroup analysis demonstrated significant improvement in EuroQol index scores post-operatively for BMI 25 kg/m2 and over. No significant difference was demonstrated for BMI 18.5 kg/m2 to 25 kg/m2. Post-operative EuroQol index scores for BMI 35 kg/m2 and over were less than pre-operative scores of all other BMI subgroups [Table 2] [Fig. 1]. Subgroup analysis of patients with or without osteoarthritis demonstrated a significantly improved EuroQol index score in patients with no osteoarthritis and early osteoarthritis. No significant difference was demonstrated in patients with moderate to advanced osteoarthritis [Table 2] [Fig. 3]. EuroQol index scores also significantly improved regardless of history of injury [Table 2] [Fig. 5] or duration of symptoms [Table 2] [Fig. 7]. Median post-operative Knee injury and Osteoarthritis Outcome Score (KOOS) significantly improved compared to pre-operative scores across all patients [Table 3].
Table 1 Table summarising cohort of patients who underwent arthroscopic meniscal surgery. Summaries presented as mean ± standard deviation (SD) and percentages (%).
Table 2 Table summarising pre-operative and post-operative EuroQol index 5Q5D5L patient reported outcome scores. Averages expressed as medians ± standard deviation. 95% confidence interval provided in brackets for parametric variables. BMI: body mass index (kg/m2). Hx: history.
All patients BMI 18.5–24.9 25–29.9 30–34.9 ≥35 Osteoarthritis None Early Moderate/advanced Hx of preceding injury Yes No Duration of symptoms b1 month 1 to 6 months N6 months a b
Post-op EuroQol
Difference
p-Value
0.642 ± 0.253
0.735 ± 0.277
0.114
b0.0001a
0.691 ± 0.221 0.681 ± 0.202 0.620 ± 0.242 0.249 ± 0.336 (0.098,0.393)
0.735 ± 0.280 0.735 ± 0.219 0.706 ± 0.279 0.422 ± 0.390 (0.233,0.567)
0.044 0.054 0.086 0.173
n.s.a b0.0001a b0.05a b0.01b
0.671 ± 0.238 0.498 ± 0.270 0.498 ± 0.252
0.735 ± 0.245 0.691 ± 0.345 0.617 ± 0.363
0.064 0.193 0.119
b0.0001a b0.05a n.s.a
0.635 ± 0.299 0.647 ± 0.235
0.735 ± 0.274 0.735 ± 0.279
0.1 0.088
b0.0001a b0.0001a
0.592 ± 0.330 0.654 ± 0.236 0.624 ± 0.246
0.735 ± 0.329 0.735 ± 0.233 0.722 ± 0.296
0.143 0.081 0.098
b0.05a b0.0001a b0.001a
Wilcoxon Signed Rank Test for paired samples. Student's t-test for paired samples.
Subgroup analysis demonstrated a significant improvement in the KOOS regardless of BMI [Table 3] [Fig. 2], history of injury [Table 3] [Fig. 6], or duration of symptoms [Table 3] [Fig. 8]. Post-operative KOOS for patients of BMI 35 kg/m2 and over was less than the preoperative scores of BMI 18.5 kg/m2 to 30 kg/m2. Subgroup analysis of patients with or without osteoarthritis demonstrated a significantly improved KOOS in patients with no osteoarthritis and early osteoarthritis. No significant difference was demonstrated in patients with moderate to advanced osteoarthritis [Table 3] [Fig. 4].
4. Discussion This study has demonstrated that benefit gained from arthroscopic meniscectomy is not just localised to the non-obese non-arthritic individual but also encompasses those of greater body habitus and those with early osteoarthritis, regardless of history of injury or duration of symptoms. We are unable to demonstrate any significant benefit in arthroscopic meniscectomy for patients with moderate to advanced osteoarthritis. The null hypothesis can therefore be rejected in relation to BMI but accepted with regard to increased severity of knee osteoarthritis. The optimal treatment of those who present with a degenerative meniscal tear remains unknown. Current NICE and AAOS guidelines advise against performing knee arthroscopy on patients with preexisting moderate to severe knee arthritis unless patients present with clinical signs of instability, locking or a suspicion of an intra-articular
BMI: EuroQol
Summary characteristics
0.9 51 ± 14 39 20 44 25 11 24 19 3 2 26 11 40 13 36
0.8 0.7 EuroQol Index Value
Age, mean ± SD (years) Female (% of patients) Body mass index (% of patients) Body mass index 18.5–24.9 kg/m2 Body mass index 25–29.9 kg/m2 Body mass index 30–34.9 kg/m2 Body mass index ≥35 kg/m2 Osteoarthritis positive (% of patients) Early Moderate Advanced History of injury (% of patients) Pain duration (% of patients) Less than 1 month 1 to 6 months 6 to 12 months Greater than 12 months
Pre-op EuroQol
0.6
BMI 18.5-24.9
0.5
BMI 25-29.9
0.4
BMI 30-34.9
0.3
BMI ≥35
0.2 0.1 0
Pre-op
Post-op
Fig. 1. Graph depicting the difference that “BMI” has on the median pre-operative and post-operative EuroQol index values. BMI groups: 18.5–24.9; 25–29.9; 30–34.9; and ≥35. BMI: body mass index (kg/m2). 95% confidence intervals represented by corresponding error bars.
O. Bailey et al. / The Knee 22 (2015) 95–99
Osteoarthritis: KOOS
Knee injury and Osteoarthrtis Outcomes Score (KOOS)
70.00 60.00 50.00
BMI 18.5-24.9
40.00
BMI 25-29.9
30.00
BMI 30-34.9
20.00
BMI ≥35
10.00
Knee injury and Osteoarthritis Outcomes Score (KOOS)
BMI: KOOS 80.00
0.00
80.00 70.00 60.00
No Osteoarthritis
50.00 40.00
Early Osteoarthritis
30.00 Moderate/Advanced Osteoarthritis
20.00 10.00 0.00
Pre-op
97
Post-op
Pre-
-op
Fig. 2. Graph depicting the difference that “BMI” has on the median pre-operative and post-operative KOOS values. BMI groups: 18.5–24.9; 25–29.9; 30–34.9; and ≥35. BMI: body mass index (kg/m2). 95% confidence intervals represented by corresponding error bars.
Fig. 4. Graph depicting the difference that “Degree of Osteoarthritis” has on the median pre-operative and post-operative KOOS values. Osteoarthritic groups: No evidence of knee osteoarthritis; evidence of early osteoarthritis only; and evidence of moderate to advanced osteoarthritis. 95% confidence intervals represented by corresponding error bars.
loose body [1,3]. Surgical success rates of arthroscopic debridement in patients with a pre-operative diagnosis of osteoarthritis range from 38–75% [9–15] however, excellent results were often short lived and in those with an increased degree of joint degeneration arthroscopy is more often than not used as a delaying tactic for definitive arthroplasty surgery. Ogilvie-Harris and Fitsialos [10] demonstrated that 68% of patients with osteoarthritis obtained symptomatic relief at two years postsurgical arthroscopic debridement, and 53% remained happy with their symptoms at four years, however they accept that the best results were obtained if the patient had resection of an unstable meniscal tear in the presence of mild arthritis. A randomised controlled trial, RCT by Hubbard [14] demonstrated the absence of pain in 59% of patients at five years who underwent arthroscopic debridement compared to 12% with arthroscopic lavage alone in patients with a single medial femoral condyle degenerative lesion of grade 3 or 4, and Steadman et al. [15] suggest that they could delay definitive arthroplasty for 10 years in
40% of the arthritic knees with Kellgren-Lawrence grade 3 & grade 4 osteoarthritis if those patients underwent arthroscopic debridement. However, they also accept that those patients of grade 4 were over five times more likely to fail compared to those with grade 3 knees. The above results however are questioned by Moseley et al. [16] who in one RCT of arthritic patients show no difference between those who underwent arthroscopic lavage, arthroscopic debridement, and arthroscopic sham surgery; leading to their conclusion that a significant proportion of positive outcomes are potentially related solely to a placebo effect. Within this study arthroscopic meniscal surgery does seem to improve average EuroQol and KOOS scores irrespective to the degree of osteoarthritis, however those perceived improvements within the moderate and advanced arthritic groups demonstrated no-statistical significance and have questionable clinical significance [17,18]. Walters and Brazier [17] suggest that a mean change of 0.074 is clinically relevant for the EQ-5D questionnaire and Roos and Lohmander [18] suggest that the minimally perceptible clinical improvement for the
Osteoarthritis: EuroQol 0.9 0.8 EuroQol Index Value
0.7 No Osteoarthritis
0.6 0.5
Early Osteoarthritis
0.4 0.3
Moderate/Advanced Osteoarthritis
0.2 0.1 0
Pre-
-op
Fig. 3. Graph depicting the difference that “Degree of Osteoarthritis” has on the median pre-operative and post-operative EuroQol index values. Osteoarthritic groups: No evidence of knee osteoarthritis; evidence of early osteoarthritis only; and evidence of moderate to advanced osteoarthritis. 95% confidence intervals represented by corresponding error bars.
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Pain duration: EuroQol 0.9
0.8
0.8
0.7
0.7
0.6 0.5
No injury recorded
0.4
Injury Recorded
0.3
EuroQol Index Value
EuroQol Index Value
History of knee injury: EuroQol 0.9
0.2
6 months
0.1 Pre-
0
-op
Fig. 5. Graph depicting the difference that “History of Injury” has on the median pre-operative and post-operative EuroQol index values. Injury groups: No history of knee trauma related to pre-operative knee symptoms; and history of knee trauma related to pre-operative knee symptoms. 95% confidence intervals represented by corresponding error bars.
KOOS is between 8 and 10, though both authors agree that the concept of a minimally important difference is difficult to quantify and is ultimately different between individual patients. It should also be noted, that the relatively low numbers of patients who were categorised as having moderate to severe osteoarthritis result in potential underpowering, and therefore a significant difference may occur within a larger cohort of patients. Further studies could expand on this, however our results do correlate with the current NICE, AAOS, and OARSI guidance. Greater BMI has long been linked to the development of osteoarthritis due mainly in part to an increased joint reaction force sustained across each knee compartment [19,20]. Morison describes in detail the joint reaction force across the tibiofemoral joint in a healthy individual during normal gait [21]. Following heel-strike the joint reaction force was observed to be 2-3 times the individual's body weight, at stancephase this force reduced slightly to twice body weight, rising to a peak just before toe-off where a joint reaction force of 2-4 times body weight was observed. Individual forces encountered within the knee joint are further described by Reilly and Martens [22] with specific focus on the patellofemoral joint. Here the maximal joint reaction force during normal walking was at the end of knee flexion and equated to about half of body weight. However, the force measured was greatly increased to the similar degree as seen through the tibiofemoral joint during a knee flexion of around 90° (squatting, climbing, or descending stairs) where forces around 2.5–3 times body weight were observed. This study has demonstrated that a similar uplift post-surgery is seen regardless of the degree of obesity and surprisingly those of BMI greater than 30 kg/m2 seem on average to have a larger proportional uplift when compared to those of BMI 18.5 kg/m2 to 30 kg/m2. A
Pre-
History of knee injury: KOOS 70.00 60.00 50.00 40.00
No injury recorded
30.00
Injury Recorded
20.00
possible explanation for this is that this study is based on patient reported outcomes and patients with a BMI greater than 30 kg/m2 are on average less active than those with a BMI less than 30 kg/m2, therefore potentially having a lower expectation of surgical endpoints. In one retrospective study of over 1000 patients Erdil et al. [23] also demonstrated a proportionately higher uplift with patients of BMI N30 kg/m2 compared to those of BMI b 26 kg/m2 at one year follow-up, however they note that the average functional outcome scores remained higher in the non-obese groups when compared to the obese groups. Interestingly, within our study the demonstrated EuroQol and KOOS postoperative outcomes of those patients of BMI 35 kg/m2 and over are less than the average pre-operative scores of those with a BMI of less than 30 kg/m2. One therefore could assume that those patients of a higher BMI could achieve a better outcome with a dedicated weight loss regime than with surgery alone. This point however has to be taken with a degree of caution, as although a higher BMI leads to an increased joint reaction force, increased “wear and tear” and therefore increased joint pain, a similar decrease in weight may not equate to a similar decrease in pain due to the cartilage damage already previously sustained. This study has a number of limitations. It is neither randomised nor blinded, and is a questionnaire based study which has a relatively low Table 3 Table summarising pre-operative and post-operative Knee injury and Osteoarthritis Outcomes Scores (KOOSs). Averages expressed as medians ± standard deviation. 95% confidence interval provided in brackets for parametric variables. BMI: body mass index (kg/m2). Hx: history.
≥35 Osteoarthritis None Early Moderate/advanced Hx of preceding injury Yes
10.00 0.00
Pre-
-op
Fig. 6. Graph depicting the difference that “History of Injury” has on the median pre-operative and post-operative KOOS values. Injury groups: No history of knee trauma related to pre-operative knee symptoms; and history of knee trauma related to pre-operative knee symptoms. 95% confidence intervals represented by corresponding error bars.
-op
Fig. 7. Graph depicting the difference “Pain Duration” has on the median pre-operative and post-operative EuroQol index values. Pain groups: pre-operative knee pain of less than 1 month; pre-operative knee pain of between 1 and 6 months; and pre-operative knee pain of over 6 months. 95% confidence intervals represented by corresponding error bars.
All patients BMI 18.5–24.9 25–29.9 30–34.9
80.00 Knee injury and Osteoarthritis Outcomes Score (KOOS)
0.5
0.2
0.1 0
0.6
No Duration of symptoms b1 month 1 to 6 months N6 months a b
Pre-op KOOS
Post-op KOOS
Difference
p-Value
44.63 ± 18.78
62.28 ± 24.94
16.85
b0.0001a
47.16 ± 16.33 50.09 ± 15.56 37.58 ± 19.27 (35.43,46.69) 22.90 ± 16.39 (18.79,32.82) 47.53 ± 18.90 36.01 ± 16.00 34.46 ± 13.03 (23.92,40.95) 44.50 ± 18.61 (37.68,46.34) 44.74 ± 18.83
60.66 ± 24.61 63.33 ± 22.20 60.27 ± 26.27 (50.35,65.70) 40.40 ± 28.91 (27.18,51.91) 63.15 ± 23.68 55.08 ± 28.36 39.41 ± 26.83 (24.09,59.15) 60.49 ± 23.07 (53.79,64.53) 62.91 ± 25.67
13.5 13.24 22.69
b0.0005a b0.0001a b0.0001b
35.31 ± 20.27 46.55 ± 17.40 43.66 ± 19.26
58.07 ± 20.59 69.34 ± 23.58 60.34 ± 26.44
Wilcoxon Signed Rank Test for paired samples. Student's t-test for paired samples.
17.5
b0.01b
15.62 19.07 4.95
b0.0001a b0.005a n.s.b
15.99
b0.0001b
18.17
b0.0001a
22.76 22.79 16.68
b0.05a b0.0001a b0.0001a
O. Bailey et al. / The Knee 22 (2015) 95–99
Knee injury and Osteoarthritis Outcomes Score (KOOS)
Pain duration: KOOS 80.00
[2]
70.00
60.00 50.00
6 months
20.00 10.00 0.00
[4]
Pre-
-op
Fig. 8. Graph depicting the difference “Pain Duration” has on the median pre-operative and post-operative KOOS values. Pain groups: pre-operative knee pain of less than 1 month; pre-operative knee pain of between 1 and 6 months; and pre-operative knee pain of over 6 months. 95% confidence intervals represented by corresponding error bars.
response rate opening it up to potential type 2 errors. Patient reported outcomes have a number of flaws on their own and can be affected by external factors. We also set very strict inclusion criteria and therefore were unable to sub-analyse the data with regard to degree/type of meniscal tear, radiographic findings, preceding symptoms of locking/ giving way, grade of surgeon performing the procedure, knee alignment, or intra/post-operative complications. Lastly, our follow-up time frame of 6-months leaves us unable to comment on long-term patient reported outcomes. Our study however is a prospective nationwide study therefore mitigating local area and selection bias so often seen with local and retrospective studies. The outcome tools used are well established and validated for the conditions observed. And lastly, this study has significant clinical relevance and will hopefully guide orthopaedic practitioners in their decision making on future patient listing for knee arthroscopy. In conclusion, arthroscopic knee meniscectomy continues to be a beneficial procedure in the Scottish population regardless of the patient's BMI, duration of symptoms, history of preceding injury, or presence of mild degree of osteoarthritis. We cannot recommend for or against meniscectomy in patients with moderate to advanced arthritis.
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[16]
[17] [18]
[19]
Conflicts of interest
[20]
I can confirm that there are no conflicts of interest with any of the manuscript authors.
[21] [22]
Acknowledgements [23]
The authors would like to thank Kate James and Services for Scotland for their contribution. References [1] No authors listedArthroscopic knee washout, with or without debridement, for the treatment of osteoarthritis. National Institute for health and Clinical Excellence
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(NICE) IPG230; Aug 2007[www.nice.org.uk/guidance/IPG230/Guidance/pdf (date last accessed 03 June 2014)]. Zhang W, Moskowitz RW, Nuki G, Abramson S, Altman RD, Arden N, biermaZeinstra S, Brandt KD, Croft P, Doherty M, Dougados M, Hochberg M, Hunter DJ, Kwoh K, Lohmander LS, Tugwell P. Osteoarthritis Research Society International recommendations for the management of hip and knee osteoarthritis, part II: OARSI evidence-based, expert consensus guidelines. Osteoarthritis and Cartilage 2008;16:137–62. No authors listedTreatment of osteoarthritis of the knee. Evidence-based guideline2nd Edition. . American Academy of Orthopaedic Surgeons (AAOS); May 2013[www.aaos.org/research/guidelines/ TreatmentofOsteoarthritisoftheKneeGuideline.pdf (date last accessed 03 June 2014)]. No authors listedReferral and pathways for patients undergoing a planned arthroscopic procedure of the knee: guidelines and current practice. A report from the Musculoskeletal Audit on behalf of the Scottish Government; 2012[http:// www.quhub.scot.uk/quality-and-efficiency/msk-and-orthopaedics-quality-drive/ sustainable-quality-pathways.aspx (date last accessed 03 June 2014)]. No authors listedKnee arthroscopy audit and patient reported outcome measures (PROMS) project 2012. A report from the Musculoskeletal Audit on behalf of the Scottish Government; 2012[http://www.quhub.scot.uk/quality-and-efficiency/ msk-and-orthopaedics-quality-drive/sustainable-quality-pathways.aspx (date last accessed 03 June 2014)]. The EuroQol Group. EuroQol—a new facility for the measurement of health-related quality of life. Health Policy 1990;16(3):199–208. Brooks R. EuroQol: the current state of play. Health Policy 1996;37(1):53–72. Roos EM, Lohmander LS. Knee injury and Osteoarthritis Outcome Score (KOOS): from joint injury to osteoarthritis. Health Qual Life Outcomes 2003;1:64. Merchan EC, Galindo E. Arthroscopy-guided surgery versus nonoperative treatment for limited degenerative osteoarthritis of the femorotibial joint in patients over 50 years of age: a prospective comparative study. Arthroscopy 1993;9(6):663–7. Ogilvie-Harris DJ, Fitsialos DP. Arthroscopic management of the degenerative knee. Arthroscopy 1991;7(2):151–7. Figueroa D, Calvo R, Villalon IE, Melean P, Novoa F, Vaisman A. Clinical outcomes after arthroscopic treatment of knee osteoarthritis. Knee 2013;20(6):591–4. McLaren AC, Blokker CP, Fowler PJ, Roth JN, Rock MG. Arthroscopic debridement of the knee for osteoarthritis. Can J Surg 1991;34(6):595–8. Baumgaetner MR, Cannon WD, Vittori JM, Schmidt ES, Maurer RC. Arthroscopic debridement of the arthritic knee. Clin Orthop Relat Res 1990;253:197–202. Hubbard MJS. Articular debridement versus washout for degeneration of the medial femoral condyle. J Bone Joint Surg (Br) 1996;78-B:217–9. Steadman JR, Briggs KK, Matheny LM, Ellis HB. Ten-year survivorship after knee arthroscopy in patients with Kellgren-Lawrence grade 3 and grade 4 osteoarthritis of the knee. Arthroscopy 2013;29(2):220–5. Moseley J, O'Malley K, Petersen N, Menke T, Brody B, Kuykendall D, et al. A controlled trial of arthroscopic surgery for osteoarthritis of the knee. N Engl J Med 2002;347:81–8. Walters SJ, Brazier JE. Comparison of the minimally important difference for two health state utility measures: EQ-5D and SF-6D. Qual Life Res 2005;14(6):1523–32. Roos EM, Lohmander LS. The Knee injury and Osteoarthritis Outcome Score (KOOS): from joint injury to osteoarthritis. Health Qual Life Outcomes 2003;1:64. http://dx. doi.org/10.1186/1477-7525-1-64 [PMCID: PMC280702]. Nordin M, Frankel VH. Basic biomechanics of the musculoskeletal system. Part II. Biomechanics of Joints. Lippincoll Williams & Wilkins; 2001 192–9. Eskelinen AP, Visuri T, Larni HM, Ritsila V. Primary cartilage lesions of the knee joint in young male adults. Overweight as a predisposing factor. An arthroscopic study. Scand J Surg 2004;93:229–33. Morison JB. The mechanics of the knee joint in relation to normal walking. J Biomech 1970;3:51–61. Reilly DT, Martens M. Experimental analysis of the quadriceps muscle force and patello-femoral joint reaction force for various activities. Acta Orthop Scand 1972; 43(2):126–37. Erdil M, Bilsel K, Sungur M, Dikmen G, Tuncer N, Polat G, et al. Does obesity negatively affect the functional results of arthroscopic partial meniscectomy? A retrospective cohort study. Arthroscopy 2013;29(2):232–7.
Contents lists available at ScienceDirect
The Knee
Effect of body mass index and osteoarthritis on outcomes following arthroscopic meniscectomy: A prospective nationwide study O. Bailey a,⁎, K. Gronkowski b, W.J. Leach a a b
Western Infirmary Glasgow, United Kingdom National Services Scotland, United Kingdom
a r t i c l e
i n f o
Article history: Received 18 June 2014 Received in revised form 6 December 2014 Accepted 17 December 2014 Keywords: Knee Arthroscopy Meniscectomy Body mass index Arthritis
a b s t r a c t Background: Current evidence suggests limiting arthroscopic meniscectomy to those patients with no or early arthritis however outcomes of arthroscopic meniscectomy with patients of a higher body mass index (BMI) are not as widely available. The aim of this study was to determine if patient reported outcome scores for arthroscopic meniscectomy are adversely affected by the degree of knee osteoarthritis or patient BMI. Methods: All patients who underwent arthroscopic meniscectomy within the NHS in Scotland between the 6th of February and 29th of April 2012 were audited as part of the Scottish Government Musculoskeletal Audit and were eligible for inclusion within this study. A total of 270 patients returned both their pre-operative and post-operative EuroQol 5Q5D5L descriptive questionnaire and Knee injury and Osteoarthritis Outcomes Scores. Patients were stratified according to BMI, degree of osteoarthritis, history of injury, and duration of knee symptoms. Results: Pre-operative to post-operative EuroQol index scores [0.642 ± 0.253 to 0.735 ± 0.277, median ± SD] and Knee injury and Osteoarthrtis Outcome Scores [44.63 ± 18.78 to 62.28 ± 24.94, median ± SD] improved across all patients (p b 0.0001). This was irrespective of degree of BMI, history of injury, or duration of symptoms. There was no such improvement in patients with moderate to severe osteoarthritis. Those patients with a BMI N35 kg/m2 had lower post-operative scores than the pre-operative scores of those of BMI b30 kg/m2. Conclusions: Arthroscopic meniscectomy is beneficial regardless of patient BMI, duration of symptoms, history of injury, or in the presence of early osteoarthritis. © 2014 Elsevier B.V. All rights reserved.
1. Introduction Arthroscopic knee surgery with or without meniscectomy is one of the most common elective orthopaedic operations carried out today. Current guidance from the National Institute for Health and Clinical Excellence (NICE) on treatment of patients with osteoarthritis suggests limiting meniscectomy to those patients who either have no preoperative osteoarthritis or in those with osteoarthritis that is in the early stage only, unless there is evidence of mechanical locking or intra-articular loose bodies [1]. Guidance from the Osteoarthritis Research Society International (OARSI) suggests that benefit from meniscectomy in an arthritic knee has limited evidence at best [2], and the most recent American Academy of Orthopaedic Surgeons (AAOS) guidance cannot recommend for or against meniscectomy in patients with a primary diagnosis of osteoarthritis [3]. In the recent Scottish Government Knee Arthroscopy Audit and Patient Reported
⁎ Corresponding author at: Specialty Registrar Trauma & Orthopaedics, Western Infirmary Glasgow, Dumbarton Road, Glasgow G11 6NT, United Kingdom. Tel.: +44 141 211 2000. E-mail address: [email protected] (O. Bailey).
http://dx.doi.org/10.1016/j.knee.2014.12.008 0968-0160/© 2014 Elsevier B.V. All rights reserved.
Outcome Measures Project 2012 [4,5] 5% of knee arthroscopies were performed on patients with moderate to severe osteoarthritis. As part of this national audit into arthroscopic knee practices within the Scottish National Health Service (NHS) we present 6-month postoperative patient reported outcomes of those patients who underwent elective knee arthroscopic meniscectomy. Our null hypothesis was that there would be no difference in patient reported outcomes when taking into account the effect of BMI or osteoarthritis after a knee arthroscopy.
2. Methods All patients who underwent arthroscopic meniscectomy within the NHS in Scotland between the 6th of February and 29th of April 2012 were audited as part of the Scottish Government Musculoskeletal Knee Arthroscopy Audit [4,5] and were eligible for inclusion within this study. All patients were sent both pre-operative and 6-month post-operative questionnaire based assessments. Patients were fully informed and consent to analyse their data was assumed to be given at the time of completing each questionnaire. Study ethical approval was obtained through the National Services Scotland (PAC Ref 67/11).
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Each pre-operative and 6-month post-operative assessment was a combination of both the EuroQol 5Q5D5L [6,7] descriptive questionnaire, to assess the general health status of the patient (questions on Mobility, Self-care, Usual Activities, Pain/Discomfort, Anxiety/Depression), and the Knee injury and Osteoarthritis Outcome Score (KOOS) [8], to assess knee specific patient reported outcome measures (questions on Symptoms, Pain, Activities of Daily Living, Sport, Quality of Life). Both the EuroQol and KOOS questionnaires have been fully validated for use in both primary injury and osteoarthritis of the knee [6–8]. In addition to the EuroQol and KOOS outcome scores the following data on each patient was obtained: age (years), BMI (kg/m2), osteoarthritis severity (grade assigned by operating surgeon using preoperative radiographs or MRI and confirmed intra-operative by direct observation. Graded as none, early, moderate, advanced), gender, knee pain duration (months), and history of preceding knee injury. Data collection and analysis were undertaken by local audit coordinators and independent statisticians. Data was collated and analysed using Excel (Microsoft, USA) and SPSS (IBM Corporation, USA). Averages are presented as means or medians ± standard deviation. Normality was assessed using the Shapiro–Wilk Test. Parametric variables were analysed with 2-sample t-tests and non-parametric variables with a 2-tailed Mann–Whitney test for independent samples and a Wilcoxon Signed-Rank test for paired samples. A 2-tailed alpha value of b 0.05 was deemed as statistical significance. 3. Results One thousand five hundred and forty seven patients underwent planned elective knee arthroscopy within the NHS in Scotland between the 6th of February 2012 and 29th of April 2012. A total of 387 patients returned both pre-operative and post-operative questionnaires. Once linked to audit data a total of 367 patients had useable data, of which 270 patients underwent arthroscopic meniscectomy and were analysed accordingly. Table 1 provides a brief descriptive summary of the data. Median post-operative EuroQol index scores significantly improved compared to preoperative scores across all patients [Table 2]. Subgroup analysis demonstrated significant improvement in EuroQol index scores post-operatively for BMI 25 kg/m2 and over. No significant difference was demonstrated for BMI 18.5 kg/m2 to 25 kg/m2. Post-operative EuroQol index scores for BMI 35 kg/m2 and over were less than pre-operative scores of all other BMI subgroups [Table 2] [Fig. 1]. Subgroup analysis of patients with or without osteoarthritis demonstrated a significantly improved EuroQol index score in patients with no osteoarthritis and early osteoarthritis. No significant difference was demonstrated in patients with moderate to advanced osteoarthritis [Table 2] [Fig. 3]. EuroQol index scores also significantly improved regardless of history of injury [Table 2] [Fig. 5] or duration of symptoms [Table 2] [Fig. 7]. Median post-operative Knee injury and Osteoarthritis Outcome Score (KOOS) significantly improved compared to pre-operative scores across all patients [Table 3].
Table 1 Table summarising cohort of patients who underwent arthroscopic meniscal surgery. Summaries presented as mean ± standard deviation (SD) and percentages (%).
Table 2 Table summarising pre-operative and post-operative EuroQol index 5Q5D5L patient reported outcome scores. Averages expressed as medians ± standard deviation. 95% confidence interval provided in brackets for parametric variables. BMI: body mass index (kg/m2). Hx: history.
All patients BMI 18.5–24.9 25–29.9 30–34.9 ≥35 Osteoarthritis None Early Moderate/advanced Hx of preceding injury Yes No Duration of symptoms b1 month 1 to 6 months N6 months a b
Post-op EuroQol
Difference
p-Value
0.642 ± 0.253
0.735 ± 0.277
0.114
b0.0001a
0.691 ± 0.221 0.681 ± 0.202 0.620 ± 0.242 0.249 ± 0.336 (0.098,0.393)
0.735 ± 0.280 0.735 ± 0.219 0.706 ± 0.279 0.422 ± 0.390 (0.233,0.567)
0.044 0.054 0.086 0.173
n.s.a b0.0001a b0.05a b0.01b
0.671 ± 0.238 0.498 ± 0.270 0.498 ± 0.252
0.735 ± 0.245 0.691 ± 0.345 0.617 ± 0.363
0.064 0.193 0.119
b0.0001a b0.05a n.s.a
0.635 ± 0.299 0.647 ± 0.235
0.735 ± 0.274 0.735 ± 0.279
0.1 0.088
b0.0001a b0.0001a
0.592 ± 0.330 0.654 ± 0.236 0.624 ± 0.246
0.735 ± 0.329 0.735 ± 0.233 0.722 ± 0.296
0.143 0.081 0.098
b0.05a b0.0001a b0.001a
Wilcoxon Signed Rank Test for paired samples. Student's t-test for paired samples.
Subgroup analysis demonstrated a significant improvement in the KOOS regardless of BMI [Table 3] [Fig. 2], history of injury [Table 3] [Fig. 6], or duration of symptoms [Table 3] [Fig. 8]. Post-operative KOOS for patients of BMI 35 kg/m2 and over was less than the preoperative scores of BMI 18.5 kg/m2 to 30 kg/m2. Subgroup analysis of patients with or without osteoarthritis demonstrated a significantly improved KOOS in patients with no osteoarthritis and early osteoarthritis. No significant difference was demonstrated in patients with moderate to advanced osteoarthritis [Table 3] [Fig. 4].
4. Discussion This study has demonstrated that benefit gained from arthroscopic meniscectomy is not just localised to the non-obese non-arthritic individual but also encompasses those of greater body habitus and those with early osteoarthritis, regardless of history of injury or duration of symptoms. We are unable to demonstrate any significant benefit in arthroscopic meniscectomy for patients with moderate to advanced osteoarthritis. The null hypothesis can therefore be rejected in relation to BMI but accepted with regard to increased severity of knee osteoarthritis. The optimal treatment of those who present with a degenerative meniscal tear remains unknown. Current NICE and AAOS guidelines advise against performing knee arthroscopy on patients with preexisting moderate to severe knee arthritis unless patients present with clinical signs of instability, locking or a suspicion of an intra-articular
BMI: EuroQol
Summary characteristics
0.9 51 ± 14 39 20 44 25 11 24 19 3 2 26 11 40 13 36
0.8 0.7 EuroQol Index Value
Age, mean ± SD (years) Female (% of patients) Body mass index (% of patients) Body mass index 18.5–24.9 kg/m2 Body mass index 25–29.9 kg/m2 Body mass index 30–34.9 kg/m2 Body mass index ≥35 kg/m2 Osteoarthritis positive (% of patients) Early Moderate Advanced History of injury (% of patients) Pain duration (% of patients) Less than 1 month 1 to 6 months 6 to 12 months Greater than 12 months
Pre-op EuroQol
0.6
BMI 18.5-24.9
0.5
BMI 25-29.9
0.4
BMI 30-34.9
0.3
BMI ≥35
0.2 0.1 0
Pre-op
Post-op
Fig. 1. Graph depicting the difference that “BMI” has on the median pre-operative and post-operative EuroQol index values. BMI groups: 18.5–24.9; 25–29.9; 30–34.9; and ≥35. BMI: body mass index (kg/m2). 95% confidence intervals represented by corresponding error bars.
O. Bailey et al. / The Knee 22 (2015) 95–99
Osteoarthritis: KOOS
Knee injury and Osteoarthrtis Outcomes Score (KOOS)
70.00 60.00 50.00
BMI 18.5-24.9
40.00
BMI 25-29.9
30.00
BMI 30-34.9
20.00
BMI ≥35
10.00
Knee injury and Osteoarthritis Outcomes Score (KOOS)
BMI: KOOS 80.00
0.00
80.00 70.00 60.00
No Osteoarthritis
50.00 40.00
Early Osteoarthritis
30.00 Moderate/Advanced Osteoarthritis
20.00 10.00 0.00
Pre-op
97
Post-op
Pre-
-op
Fig. 2. Graph depicting the difference that “BMI” has on the median pre-operative and post-operative KOOS values. BMI groups: 18.5–24.9; 25–29.9; 30–34.9; and ≥35. BMI: body mass index (kg/m2). 95% confidence intervals represented by corresponding error bars.
Fig. 4. Graph depicting the difference that “Degree of Osteoarthritis” has on the median pre-operative and post-operative KOOS values. Osteoarthritic groups: No evidence of knee osteoarthritis; evidence of early osteoarthritis only; and evidence of moderate to advanced osteoarthritis. 95% confidence intervals represented by corresponding error bars.
loose body [1,3]. Surgical success rates of arthroscopic debridement in patients with a pre-operative diagnosis of osteoarthritis range from 38–75% [9–15] however, excellent results were often short lived and in those with an increased degree of joint degeneration arthroscopy is more often than not used as a delaying tactic for definitive arthroplasty surgery. Ogilvie-Harris and Fitsialos [10] demonstrated that 68% of patients with osteoarthritis obtained symptomatic relief at two years postsurgical arthroscopic debridement, and 53% remained happy with their symptoms at four years, however they accept that the best results were obtained if the patient had resection of an unstable meniscal tear in the presence of mild arthritis. A randomised controlled trial, RCT by Hubbard [14] demonstrated the absence of pain in 59% of patients at five years who underwent arthroscopic debridement compared to 12% with arthroscopic lavage alone in patients with a single medial femoral condyle degenerative lesion of grade 3 or 4, and Steadman et al. [15] suggest that they could delay definitive arthroplasty for 10 years in
40% of the arthritic knees with Kellgren-Lawrence grade 3 & grade 4 osteoarthritis if those patients underwent arthroscopic debridement. However, they also accept that those patients of grade 4 were over five times more likely to fail compared to those with grade 3 knees. The above results however are questioned by Moseley et al. [16] who in one RCT of arthritic patients show no difference between those who underwent arthroscopic lavage, arthroscopic debridement, and arthroscopic sham surgery; leading to their conclusion that a significant proportion of positive outcomes are potentially related solely to a placebo effect. Within this study arthroscopic meniscal surgery does seem to improve average EuroQol and KOOS scores irrespective to the degree of osteoarthritis, however those perceived improvements within the moderate and advanced arthritic groups demonstrated no-statistical significance and have questionable clinical significance [17,18]. Walters and Brazier [17] suggest that a mean change of 0.074 is clinically relevant for the EQ-5D questionnaire and Roos and Lohmander [18] suggest that the minimally perceptible clinical improvement for the
Osteoarthritis: EuroQol 0.9 0.8 EuroQol Index Value
0.7 No Osteoarthritis
0.6 0.5
Early Osteoarthritis
0.4 0.3
Moderate/Advanced Osteoarthritis
0.2 0.1 0
Pre-
-op
Fig. 3. Graph depicting the difference that “Degree of Osteoarthritis” has on the median pre-operative and post-operative EuroQol index values. Osteoarthritic groups: No evidence of knee osteoarthritis; evidence of early osteoarthritis only; and evidence of moderate to advanced osteoarthritis. 95% confidence intervals represented by corresponding error bars.
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Pain duration: EuroQol 0.9
0.8
0.8
0.7
0.7
0.6 0.5
No injury recorded
0.4
Injury Recorded
0.3
EuroQol Index Value
EuroQol Index Value
History of knee injury: EuroQol 0.9
0.2
6 months
0.1 Pre-
0
-op
Fig. 5. Graph depicting the difference that “History of Injury” has on the median pre-operative and post-operative EuroQol index values. Injury groups: No history of knee trauma related to pre-operative knee symptoms; and history of knee trauma related to pre-operative knee symptoms. 95% confidence intervals represented by corresponding error bars.
KOOS is between 8 and 10, though both authors agree that the concept of a minimally important difference is difficult to quantify and is ultimately different between individual patients. It should also be noted, that the relatively low numbers of patients who were categorised as having moderate to severe osteoarthritis result in potential underpowering, and therefore a significant difference may occur within a larger cohort of patients. Further studies could expand on this, however our results do correlate with the current NICE, AAOS, and OARSI guidance. Greater BMI has long been linked to the development of osteoarthritis due mainly in part to an increased joint reaction force sustained across each knee compartment [19,20]. Morison describes in detail the joint reaction force across the tibiofemoral joint in a healthy individual during normal gait [21]. Following heel-strike the joint reaction force was observed to be 2-3 times the individual's body weight, at stancephase this force reduced slightly to twice body weight, rising to a peak just before toe-off where a joint reaction force of 2-4 times body weight was observed. Individual forces encountered within the knee joint are further described by Reilly and Martens [22] with specific focus on the patellofemoral joint. Here the maximal joint reaction force during normal walking was at the end of knee flexion and equated to about half of body weight. However, the force measured was greatly increased to the similar degree as seen through the tibiofemoral joint during a knee flexion of around 90° (squatting, climbing, or descending stairs) where forces around 2.5–3 times body weight were observed. This study has demonstrated that a similar uplift post-surgery is seen regardless of the degree of obesity and surprisingly those of BMI greater than 30 kg/m2 seem on average to have a larger proportional uplift when compared to those of BMI 18.5 kg/m2 to 30 kg/m2. A
Pre-
History of knee injury: KOOS 70.00 60.00 50.00 40.00
No injury recorded
30.00
Injury Recorded
20.00
possible explanation for this is that this study is based on patient reported outcomes and patients with a BMI greater than 30 kg/m2 are on average less active than those with a BMI less than 30 kg/m2, therefore potentially having a lower expectation of surgical endpoints. In one retrospective study of over 1000 patients Erdil et al. [23] also demonstrated a proportionately higher uplift with patients of BMI N30 kg/m2 compared to those of BMI b 26 kg/m2 at one year follow-up, however they note that the average functional outcome scores remained higher in the non-obese groups when compared to the obese groups. Interestingly, within our study the demonstrated EuroQol and KOOS postoperative outcomes of those patients of BMI 35 kg/m2 and over are less than the average pre-operative scores of those with a BMI of less than 30 kg/m2. One therefore could assume that those patients of a higher BMI could achieve a better outcome with a dedicated weight loss regime than with surgery alone. This point however has to be taken with a degree of caution, as although a higher BMI leads to an increased joint reaction force, increased “wear and tear” and therefore increased joint pain, a similar decrease in weight may not equate to a similar decrease in pain due to the cartilage damage already previously sustained. This study has a number of limitations. It is neither randomised nor blinded, and is a questionnaire based study which has a relatively low Table 3 Table summarising pre-operative and post-operative Knee injury and Osteoarthritis Outcomes Scores (KOOSs). Averages expressed as medians ± standard deviation. 95% confidence interval provided in brackets for parametric variables. BMI: body mass index (kg/m2). Hx: history.
≥35 Osteoarthritis None Early Moderate/advanced Hx of preceding injury Yes
10.00 0.00
Pre-
-op
Fig. 6. Graph depicting the difference that “History of Injury” has on the median pre-operative and post-operative KOOS values. Injury groups: No history of knee trauma related to pre-operative knee symptoms; and history of knee trauma related to pre-operative knee symptoms. 95% confidence intervals represented by corresponding error bars.
-op
Fig. 7. Graph depicting the difference “Pain Duration” has on the median pre-operative and post-operative EuroQol index values. Pain groups: pre-operative knee pain of less than 1 month; pre-operative knee pain of between 1 and 6 months; and pre-operative knee pain of over 6 months. 95% confidence intervals represented by corresponding error bars.
All patients BMI 18.5–24.9 25–29.9 30–34.9
80.00 Knee injury and Osteoarthritis Outcomes Score (KOOS)
0.5
0.2
0.1 0
0.6
No Duration of symptoms b1 month 1 to 6 months N6 months a b
Pre-op KOOS
Post-op KOOS
Difference
p-Value
44.63 ± 18.78
62.28 ± 24.94
16.85
b0.0001a
47.16 ± 16.33 50.09 ± 15.56 37.58 ± 19.27 (35.43,46.69) 22.90 ± 16.39 (18.79,32.82) 47.53 ± 18.90 36.01 ± 16.00 34.46 ± 13.03 (23.92,40.95) 44.50 ± 18.61 (37.68,46.34) 44.74 ± 18.83
60.66 ± 24.61 63.33 ± 22.20 60.27 ± 26.27 (50.35,65.70) 40.40 ± 28.91 (27.18,51.91) 63.15 ± 23.68 55.08 ± 28.36 39.41 ± 26.83 (24.09,59.15) 60.49 ± 23.07 (53.79,64.53) 62.91 ± 25.67
13.5 13.24 22.69
b0.0005a b0.0001a b0.0001b
35.31 ± 20.27 46.55 ± 17.40 43.66 ± 19.26
58.07 ± 20.59 69.34 ± 23.58 60.34 ± 26.44
Wilcoxon Signed Rank Test for paired samples. Student's t-test for paired samples.
17.5
b0.01b
15.62 19.07 4.95
b0.0001a b0.005a n.s.b
15.99
b0.0001b
18.17
b0.0001a
22.76 22.79 16.68
b0.05a b0.0001a b0.0001a
O. Bailey et al. / The Knee 22 (2015) 95–99
Knee injury and Osteoarthritis Outcomes Score (KOOS)
Pain duration: KOOS 80.00
[2]
70.00
60.00 50.00
6 months
20.00 10.00 0.00
[4]
Pre-
-op
Fig. 8. Graph depicting the difference “Pain Duration” has on the median pre-operative and post-operative KOOS values. Pain groups: pre-operative knee pain of less than 1 month; pre-operative knee pain of between 1 and 6 months; and pre-operative knee pain of over 6 months. 95% confidence intervals represented by corresponding error bars.
response rate opening it up to potential type 2 errors. Patient reported outcomes have a number of flaws on their own and can be affected by external factors. We also set very strict inclusion criteria and therefore were unable to sub-analyse the data with regard to degree/type of meniscal tear, radiographic findings, preceding symptoms of locking/ giving way, grade of surgeon performing the procedure, knee alignment, or intra/post-operative complications. Lastly, our follow-up time frame of 6-months leaves us unable to comment on long-term patient reported outcomes. Our study however is a prospective nationwide study therefore mitigating local area and selection bias so often seen with local and retrospective studies. The outcome tools used are well established and validated for the conditions observed. And lastly, this study has significant clinical relevance and will hopefully guide orthopaedic practitioners in their decision making on future patient listing for knee arthroscopy. In conclusion, arthroscopic knee meniscectomy continues to be a beneficial procedure in the Scottish population regardless of the patient's BMI, duration of symptoms, history of preceding injury, or presence of mild degree of osteoarthritis. We cannot recommend for or against meniscectomy in patients with moderate to advanced arthritis.
[5]
[6] [7] [8] [9]
[10] [11] [12] [13] [14] [15]
[16]
[17] [18]
[19]
Conflicts of interest
[20]
I can confirm that there are no conflicts of interest with any of the manuscript authors.
[21] [22]
Acknowledgements [23]
The authors would like to thank Kate James and Services for Scotland for their contribution. References [1] No authors listedArthroscopic knee washout, with or without debridement, for the treatment of osteoarthritis. National Institute for health and Clinical Excellence
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