Full AccessResearch Report

Quality of Life in Symptomatic Individuals After Anterior Cruciate Ligament Reconstruction, With and Without Radiographic Knee Osteoarthritis

Authors

affiliations

Journal of Orthopaedic & Sports Physical Therapy

Published Online:April 30, 2018Volume48Issue5Pages398-408

https://www.jospt.org/doi/10.2519/jospt.2018.7830

Abstract

Study Design

Clinical measurement, cross-sectional.

Background

Individuals who have undergone anterior cruciate ligament (ACL) reconstruction commonly experience long-term impairments in quality of life (QoL), which may be related to persistent knee symptoms or radiographic osteoarthritis (ROA). Understanding the impact of knee symptoms and ROA on QoL after ACL reconstruction may assist in the development of appropriate management strategies.

Objectives

To (1) compare QoL between groups of individuals after ACL reconstruction (including those who are symptomatic with ROA, symptomatic without ROA, and asymptomatic [unknown ROA status]), and (2) identify specific aspects of QoL impairment in symptomatic individuals with and without ROA post ACL reconstruction.

Methods

One hundred thirteen participants completed QoL measures (Knee injury and Osteoarthritis Outcome Score QoL subscale [KOOS-QoL], Anterior Cruciate Ligament Quality of Life [ACL-QoL], Assessment of Quality of Life-8 Dimensions [AQoL-8D]) 5 to 20 years after ACL reconstruction. Eighty-one symptomatic individuals underwent radiographs, and 32 asymptomatic individuals formed a comparison group. Radiographic osteoarthritis was defined as a Kellgren-Lawrence grade of 2 or greater for the tibiofemoral and/or patellofemoral joints. Mann-Whitney U tests compared outcomes between groups. Individual ACL-QoL items were used to explore specific aspects of QoL.

Results

In symptomatic individuals after ACL reconstruction, ROA was related to worse knee-related outcomes on the KOOS-QoL (median, 50; interquartile range [IQR], 38–69 versus median, 69; IQR, 56–81; P<.001) and the ACL-QoL (median, 51; IQR, 38–71 versus median, 66; IQR, 50–82; P = .04). The AQoL-8D scores showed that health-related QoL was impaired in both symptomatic groups compared to the asymptomatic group. The ACL-QoL item scores revealed greater limitations and concern surrounding sport and exercise and social/emotional difficulties in the symptomatic group with ROA.

Conclusion

Osteoarthritis is associated with worse knee-related QoL in symptomatic individuals after ACL reconstruction. Diagnosing ROA in symptomatic individuals after ACL reconstruction may be valuable, because these individuals may require unique management. Targeted strategies to facilitate participation in satisfying activities have potential to improve QoL in symptomatic people with ROA after ACL reconstruction. J Orthop Sports Phys Ther 2018;48(5):398–408. doi:10.2519/jospt.2018.7830

Osteoarthritis of the knee is a leading cause of disability worldwide.⁵ Individuals who experience symptomatic radiographic osteoarthritis (ROA) may endure chronic pain and physical activity limitations that can impact quality of life (QoL).¹^,⁵^,³¹ Although knee ROA is most prevalent among older adults,⁵ young individuals participating in competitive sport who rupture their anterior cruciate ligament (ACL) are at high risk of developing knee ROA within 10 years of injury.²²^,²⁸ The desire to continue participation in high-impact sports, combined with work and parenting responsibilities inherent in these young adults, may contribute to the impaired QoL described in some individuals 5 to 20 years after ACL reconstruction.⁹^,¹⁰ However, the impact of symptomatic ROA on QoL after ACL reconstruction is poorly understood. Consequently, the clinical importance of diagnosing ROA in symptomatic individuals after ACL reconstruction is unclear, and information to guide strategies to improve QoL in this population is limited.

After ACL reconstruction, QoL was similar between individuals with and without tibiofemoral ROA (defined as a Kellgren-Lawrence grade of 2 or above¹⁴).⁶^,²⁰^,²⁴ However, QoL was worse in people with severe tibiofemoral ROA after ACL reconstruction (Kellgren-Lawrence grade 4) compared to those without ROA.²⁴ The impact of patellofemoral ROA on QoL is unclear, due to disagreement in the literature.⁶^,²¹^,²³ To date, all studies investigating the relationship between QoL and ROA after ACL reconstruction have not considered symptomatic status. Consequently, the complex relationship between knee symptoms, ROA, and QoL following ACL reconstruction has not been investigated. Additionally, the relevance of ROA findings in symptomatic individuals after ACL reconstruction is uncertain. An exploration of QoL among symptomatic individuals after ACL reconstruction, with and without ROA, could provide new insights.

The aims of this study were (1) to compare QoL between individuals after ACL reconstruction who were (a) symptomatic with ROA, (b) symptomatic without ROA, and (c) asymptomatic (unknown ROA status); and (2) to identify specific aspects of QoL impairment in symptomatic individuals with and without ROA after ACL reconstruction.

Methods

Study Design

This cross-sectional study was reported according to the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist for cross-sectional studies. Ethical approval for this study was obtained from the University of Queensland Medical Research Ethics Committee (approval number 2012001240).

Participants

Individuals were recruited from a larger cross-sectional study investigating QoL in people with knee difficulties 5 to 20 years following ACL reconstruction.⁹ Details of the recruitment procedure and eligibility criteria for the larger study have been published previously.⁹ In brief, to be eligible for the cross-sectional study, individuals had to be 18 to 55 years of age, have had a hamstring or patellar tendon autograft ACL reconstruction 5 to 20 years previously, report no substantial comorbidities likely to impact QoL, and report knee difficulties. Considering no validated criteria exist for categorizing individuals post ACL reconstruction as “symptomatic,” we adapted published criteria for the purposes of this study.⁹^,²⁶ Symptomatic knee status was defined as reporting impairment on at least 2 Knee injury and Osteoarthritis Outcome Score (KOOS) subscales. Impairment was determined by a 1-step decrease from the best response to at least 50% of items within a subscale, which determined the following cutoffs: pain less than or equal to 86.1, symptoms less than or equal to 85.7, activities of daily living less than or equal to 86.8, sport and recreation less than or equal to 85.0, and QoL less than or equal to 87.5. Thirty-two of the 194 individuals who completed the questionnaire did not meet the KOOS cutoff criteria and were categorized as asymptomatic. These individuals were not invited for a knee radiograph, but their questionnaire data were used for comparison with symptomatic individuals post ACL reconstruction. Study information and an invitation to receive a knee radiograph were sent to all 162 individuals who met the KOOS cutoff criteria. FIGURE 1 describes the recruitment process for the present study, which included radiographs from 81 individuals for grading and analysis.

**FIGURE 1.** Participant recruitment flow chart. The KOOS cutoff criteria for symptomatic knee status were determined by applying a cutoff that equates to a 1-step decrease from the best response for at least 50% of items within 2 or more subscales (resulting in the following cutoffs: pain, 86.1 or lower; symptoms, 85.7 or lower; activities of daily living, 86.8 or lower; sport/recreation, 85.0 or lower; and quality of life, 87.5 or lower). Abbreviations: KOOS, Knee injury and Osteoarthritis Outcome Score; PRO, patient-reported outcome.

Radiographic Assessment

Radiographic clinics across Australia were contacted prior to receiving a referral and informed of the study protocol and procedure. Three views of the ACL-reconstructed knee(s) were requested to enable radiographic grading of the tibiofemoral and patellofemoral joints: weight-bearing posteroanterior erect in 15° of knee flexion, weight-bearing lateral in 30° of knee flexion, and non-weight-bearing skyline in 45° of knee flexion. All radiographs were graded by an experienced radiologist (S.D.) using the Kellgren-Lawrence criteria for defining ROA,¹⁴ by which osteophytes, narrowing of joint cartilage, sclerotic or pseudocystic subchondral bone, and an altered shape of the tibial or femoral condyles were considered signs of ROA. A Kellgren-Lawrence score of grade 0 represents no radiographic changes, grade 1 minimal changes, grade 2 definite but minimal changes, grade 3 moderate changes, and grade 4 severe radiographic changes.¹⁴ A Kellgren-Lawrence score of grade 2 or greater for the tibiofemoral or patellofemoral joint was used to define the presence of ROA.¹⁴ Radiographic osteoarthritis was further classified by the following involved compartments: medial tibiofemoral, lateral tibiofemoral, and patellofemoral. All knee radiographs were performed between September 2014 and August 2015, at a median of 9 months (interquartile range [IQR], 8–11 months) after questionnaire completion.

Although symptomatic osteoarthritis can be diagnosed without imaging,²⁷ the presence of knee symptoms without structural changes cannot be confidently attributed to osteoarthritis.¹⁵ Therefore, we assumed that the symptomatic group with ROA would have more symptoms related to the ROA disease process than would the symptomatic group without ROA.

Participant Characteristics

A range of information regarding participant characteristics and demographics was collected as part of the parent study. This included age, body mass index, time since last ACL reconstruction, time from injury to ACL reconstruction (dichotomized to 6 months or shorter versus longer than 6 months), contact mechanism of injury, additional surgery (additional knee surgery to an ACL-reconstructed knee not including revision ACL reconstruction or concomitant surgery performed at the time of primary or revision ACL reconstruction), and revision ACL reconstruction (yes/no). Return to sport was also assessed using the following question: “Please tick the most appropriate statement regarding your level of sport participation after injuring your ACL by selecting 1 of the following 3 options: ‘I returned to competitive sport at the same or higher level than before ACL injury,’ ‘I returned to competitive sport at a lower level than before ACL injury,’ or ‘I did not return to competitive sport after my ACL reconstruction.’” The proportion of participants receiving current knee treatment was assessed (“Do you currently receive treatment for your knee?”), and participants were asked, “How would you rate your current knowledge of osteoarthritis?” with responses on a 5-point Likert scale (very good, good, average, poor, very poor). Due to potential difficulty recalling information surrounding the ACL injury and surgery, “unsure” response options were given (ie, questions on mechanism of ACL injury and time from injury to ACL reconstruction).

Patient-Reported Measures

All patient-reported measures used for this study were collected as part of the larger cross-sectional study. The psychometric properties for these instruments have been previously described.⁹

Knee-Related QoL The Anterior Cruciate Ligament Quality of Life (ACL-QoL) was chosen as the primary measure to evaluate knee-related QoL, because this is the only ACL-specific QoL measure¹⁸ and contains items of clear relevance to individuals with ACL injuries.²⁹ A unique attribute of the ACL-QoL is use of terminology that enables the responder to consider the personal impact that pain or physical deficits have on their life (eg, “How troubled are you by pain or stiffness?” and “How much of a concern is it for you to miss days from work?”). The ACL-QoL contains 31 items that fall under 5 separate domains: symptoms and physical complaints, work-related concerns, recreational activities and sport participation or competition, lifestyle, and social and emotional.¹⁸ Each item is scored on a visual analog scale ranging from 0 (severe impairment) to 100 (no impairment). Item scores are averaged to calculate the overall ACL-QoL score (range, 0–100). The ACL-QoL scores are valid for use in individuals with ACL injuries and with chronic knee difficulties,¹⁸ and have high internal consistency (Cronbach α≥.93) at 6, 12, and 24 months following ACL reconstruction.¹⁶ The ACL-QoL has been found to be responsive (using anchor-based methods) to self-rated knee improvement before and more than 2 years following ACL reconstruction.¹⁶

The KOOS was used as a secondary measure of QoL, because this is the most commonly used measure of longer-term QoL in populations with ACL reconstruction,¹⁰ enabling comparisons with previous studies. The KOOS-QoL subscale comprises 4 questions addressing knee awareness, knee-related lifestyle modifications, knee confidence, and knee-related difficulties.²⁶ The KOOS items are scored on a 5-point ordinal scale, from which subscale scores are calculated ranging from 0 (severe impairment) to 100 (no impairment).

Health-Related QoL The Assessment of Quality of Life-8 Dimensions (AQoL-8D) instrument is a general health-related QoL measure with strong content, construct, and discriminative validity in populations with osteoarthritis.¹²^,¹³^,²⁵^,³⁰ The AQoL-8D includes 8 dimensions (independent living, happiness, mental health, coping, relationships, self-worth, pain, senses). The AQoL-8D can provide both unweighted summary scores and weighted utility scores. Utility scores were calculated for this study. The AQoL-8D utility scores are scaled such that 0.00 represents the worst health state and 1.00 represents the best health state.

Statistical Analysis

The assumption of normality was not met for several variables; consequently, nonparametric tests were chosen, and data are reported as medians and IQRs or frequencies and percentages, as appropriate. To minimize the total number of group comparisons, we used the Kruskal-Wallis test to compare outcomes between the 3 groups. The distribution of scores was not homogeneous between groups (due to higher scores in the asymptomatic group); therefore, Kruskal-Wallis tests were performed with mean ranks rather than median scores. Differences accompanied by P less than .05 were analyzed post hoc using Mann-Whitney U tests to determine which groups were statistically different.

To assess whether people volunteering to undergo a knee radiograph were representative of the larger cross-sectional study sample, Mann-Whitney U and chi-square tests were used, as appropriate. Due to the small amount of missing data (KOOS, no missing data; ACL-QoL, n = 1 missing data [asymptomatic group]; AQoL-8D, n = 2 missing data [asymptomatic group]), analyses were performed where complete data were available (ie, data from the 3 questionnaires that were incomplete were not included in the analysis).

Results

Sample Characteristics

Participant characteristics are described in TABLE 1. Symptomatic participants were older than asymptomatic participants (median, 40 years; IQR, 34–49 years versus median, 34 years; IQR, 29–45 years; P = .04), more symptomatic participants had undergone additional knee surgery (54% versus 19%, P = .001), and fewer symptomatic participants had returned to a preinjury level of sport compared with asymptomatic participants (37% versus 63%, P = .01).

TABLE 1 Sample Characteristics*
	All Symptomatic (n = 81)	Asymptomatic (Unknown ROA Status) (n = 32)	P Value^†	Symptomatic With ROA (n = 50)	Symptomatic Without ROA (n = 31)	P Value^†
Age, y	40 (34–49)	34 (29–45)	.04	42 (36–49)	37 (32–43)	.02
Sex (male), n (%)	42 (52)	17 (53)	.90	27 (54)	15 (48)	.62
BMI (overweight or obese), n (%)^‡	49 (61)	18 (56)	.31	35 (70)	14 (45)	.03
Years since last ACL reconstruction, y	8 (7–11)	8 (7–11)	.82	9 (7–11)	8 (6–8)	.01
>6-mo ACL reconstruction delay, n (%)^§	23 (28)	8 (25)	.69	20 (41)	3 (10)	.003
Additional knee surgery, n (%)	44 (54)	6 (19)	.001	33 (66)	11 (35)	.007
Revision ACL reconstruction, n (%)	12 (15)	2 (6)	.21	9 (18)	3 (10)	.31
Contact mechanism of injury, n (%)^‖	29 (36)	12 (40)	.75	13 (27)	16 (52)	.03
RTS at preinjury/higher level, n (%)	30 (37)	20 (63)	.01	17 (34)	13 (42)	.47
RTS at a lower level, n (%)	22 (27)	6 (19)	.20	12 (24)	10 (32)	.42
Did not RTS, n (%)	29 (36)	6 (19)	.08	21 (42)	8 (26)	.14

Abbreviations: ACL, anterior cruciate ligament; BMI, body mass index; ROA, radiographic osteoarthritis; RTS, return to sport.

*Values are median (interquartile range) unless otherwise indicated.

^†Calculated using Mann-Whitney U (continuous variables) or chi-square tests (binary variables).

^‡Converted to a binary variable (normal weight versus overweight or obese), with reference to international classification guidelines (normal weight, 18.9–24.9 kg/m²; overweight, 25.0–29.9 kg/m²; obese, 30.0 kg/m² or greater).¹⁹

^§“Unsure” responses were removed, resulting in 1 missing response (from the symptomatic group with ROA).

^‖“Unsure” responses were removed, resulting in 4 missing responses (2 from the symptomatic group with ROA and 2 from the asymptomatic group).

Compared to symptomatic participants without ROA, symptomatic participants with ROA were older (median age, 42 years; IQR, 36–49 years versus 37 years; IQR, 32–43 years; P = .02) and more overweight or obese (70% versus 45%, P = .03), and had more time since their ACL reconstruction (median, 9 years; IQR, 7–11 years versus 8 years; IQR, 6–8 years; P = .01). Symptomatic participants with ROA were also more likely to have reported a delay of greater than 6 months from ACL injury to reconstruction (41% versus 10%, P = .003), were more likely to have undergone additional knee surgery (66% versus 35%, P = .007), and were less likely to have reported a contact mechanism of ACL injury (27% versus 52%, P = .03). A similar proportion of symptomatic participants with and without ROA received current knee treatment (20% and 19%, respectively). Before undergoing a knee radiograph, 30% of symptomatic participants rated their osteoarthritis knowledge as good/very good (34% with ROA, 23% without ROA), 30% as average (34% with ROA, 23% without ROA), and 41% as poor/very poor (32% with ROA, 55% without ROA).

There were no statistical differences in sex, body mass index, time since ACL reconstruction, proportion having additional surgery, dissatisfaction with knee function, KOOS pain score, KOOS symptoms score, or ACL-QoL score between those who underwent radiographs (n = 81) and symptomatic individuals without radiographs from the parent study (n = 81) (P>.05 for all analyses). The only statistical difference between these groups was age, such that individuals who underwent radiographs were younger than symptomatic individuals who did not undergo a knee radiograph (median age, 36 years versus 40 years; IQR, 34–49 years; P = .01).

Radiographic Findings

The prevalence of ROA by knee compartment and radiographic severity score is presented in FIGURE 2. When all compartments were considered together, 2 (2.5%) participants had grade 0 (no) ROA, 29 (36%) had grade 1 (minimal) ROA, 28 (34.5%) had grade 2 (definite) ROA, 15 (18.5%) had grade 3 (moderate) ROA, and 7 (8.5%) had grade 4 (severe) ROA.

**FIGURE 2.** Knee ROA prevalence by compartment and severity (n = 81). “All compartments” presents the highest grade of ROA from any compartment for each participant. A Kellgren-Lawrence grade of 0 represents no radiographic changes, grade 1 represents minimal changes, grade 2 represents definite but minimal changes, grade 3 represents moderate changes, and grade 4 represents severe radiographic changes.¹⁴ If both knees were reconstructed, the highest severity of ROA in either knee was reported for each compartment. Abbreviations: PFJ, patellofemoral joint; ROA, radiographic osteoarthritis; TFJ, tibiofemoral joint.

Comparisons in QoL

Knee-Related QoL Symptomatic participants with ROA reported worse QoL on the KOOS-QoL subscale (median, 50; IQR, 38–69 versus 69; IQR, 56–81; P<.001) and the ACL-QoL (median, 51; IQR, 38–71 versus 66; IQR, 50–82; P = .04) compared to symptomatic participants without ROA (FIGURE 3). Asymptomatic participants reported better KOOS and ACL-QoL scores compared with symptomatic participants with and without ROA (all, P<.001).

**FIGURE 3.** Comparison of KOOS subscale scores and total ACL-QoL scores in symptomatic people after ACL reconstruction (with and without ROA) and asymptomatic participants. All outcomes were reported as medians, and error bars represent interquartile ranges. A score of 100 represents the best possible score for each outcome. P values were obtained using Mann-Whitney U tests and are reported for symptomatic with ROA (blue) versus symptomatic without ROA (orange). Abbreviations: ACL, anterior cruciate ligament; ACL-QoL, Anterior Cruciate Ligament Quality of Life questionnaire; ADL, activities of daily living; KOOS, Knee injury and Osteoarthritis Outcome Score; QoL, quality of life; ROA, radiographic osteoarthritis.

Health-Related QoL No statistical differences were observed in overall AQoL-8D scores between symptomatic participants with and without ROA (FIGURE 4). However, all AQoL-8D domains and utility scores were impaired in symptomatic participants with and without ROA compared to asymptomatic individuals (all, P<.03), with the exception of the self-worth domain, which was not statistically different between symptomatic participants without ROA and asymptomatic participants (P = .12).

**FIGURE 4.** Comparison of Assessment of Quality of Life-8 Dimensions utility scores in symptomatic people after ACL reconstruction (with and without ROA) and asymptomatic participants. All outcomes were reported as medians, and error bars represent interquartile ranges. A score of 1.0 represents the best possible score. P values were obtained using Mann-Whitney U tests and are reported for symptomatic with ROA (blue) versus symptomatic without ROA (orange). Abbreviations: ACL, anterior cruciate ligament; ROA, radiographic osteoarthritis.

Specific Aspects of QoL Impairment

Symptoms and Physical Complaints Pain, stiffness, and knee weakness were common among symptomatic participants, but trouble with giving-way episodes was rare (TABLE 2). There were no statistical differences in the impact of symptoms and physical complaints on QoL of symptomatic individuals with and without ROA (TABLE 2). Symptoms and physical complaints were more impaired in symptomatic participants with ROA (all items, P≤.003) and without ROA (all items, P≤.001) compared to asymptomatic individuals.

TABLE 2 ACL-QoL Item Scores and Comparison Between ACL-Reconstructed Groups*
ACL-QoL Item	Symptomatic With ROA (n = 50)	Symptomatic Without ROA (n = 31)	Asymptomatic (Unknown ROA Status) (n = 31)^†
Symptoms and physical complaints
1. With respect to your overall knee function, how troubled are you by giving-way episodes?
a. Severity of giving-way episodes	99 (83–100)	96 (90–100)	100 (100–100)
b. Frequency of giving-way episodes	98 (88–100)	96 (90–100)	100 (100–100)
2. With any kind of prolonged activity (ie, >30 min), how much pain or discomfort do you get in your knee?	68 (44–87)	83 (54–87)	100 (90–100)
3. With respect to your overall knee function, how much are you troubled by stiffness or loss of motion in your knee?	77 (43–92)	79 (58–88)	96 (86–100)
4. Consider the overall function of your knee and how it relates to the strength of your muscles. How weak is your knee?	64 (38–84)	72 (48–85)	93 (86–100)
Work-related concerns
5. How much trouble do you have, because of your knee, with turning or pivoting motions at work?	92 (75–100)	100 (89–100)	100 (100–100)
6. How much trouble do you have, because of your knee, with squatting motions at work?	57 (26–90)	75 (50–97)	100 (96–100)
7. How much of a concern is it for you to miss days from work due to problems or reinjury to your knee?	100 (53–100)	100 (86–100)	100 (100–100)
8. How much of a concern is it for you to lose time from “school” or work because of the treatment of your ACL-reconstructed knee?	99 (53–100)	100 (88–100)	100 (100–100)
Recreational activities and sport participation or competition
9. How much limitation do you have with sudden twisting and pivoting movements or changes in direction?	63 (31–97)	72 (53–90)	99 (88–100)
10. How much of a concern is it for you that your sporting or recreational activities may result in the status of your knee worsening?	27 (2–53)	27 (12–65)	64 (50–100)
11. How does your current level of athletic or recreational performance compare with your preinjury level?	32 (11–75)^‡	61 (48–80)	95 (78–100)
12. With respect to activities/sports that you desire to be involved with, how much have your expectations changed because of your knee?	29 (6–71)	50 (25–74)	97 (81–100)
13. Do you have to play your recreation or sport under caution?	18 (0–49)^§	47 (3–90)	86 (54–100)
14. How fearful are you of your knee giving way when playing recreation or sport?	30 (6–74)	61 (13–100)	94 (63–100)
15. Are you concerned about environmental conditions, such as a wet playing field or a hard court, when involved in your recreation or sport?	20 (6–68)^§	53 (18–90)	90 (50–100)
16. Do you find it frustrating to have to consider your knee with respect to your recreation or sport?	15 (0–49)	35 (4–90)	94 (79–100)
17. How difficult is it for you to “go full out” at your recreation or sport?	13 (0–50)^§	47 (11–92)	90 (56–100)
18. Are you fearful of playing contact sports?	10 (0–47)^§	45 (9–84)	90 (46–100)
19. How limited are you in playing the number “1” sport or activity?	39 (1–82)	70 (36–90)	96 (85–100)
20. How limited are you in playing the number “2” sport or activity?	34 (0–75)^§	71 (22–94)	96 (81–100)
Lifestyle
21. Do you have to concern yourself with general safety issues (eg, carrying small children, working in the yard) with respect to your knee?	85 (50–100)^‡	100 (82–100)	100 (100–100)
22. How much has your ability to exercise and maintain fitness been limited by your knee problem?	47 (22–81)^‡	84 (50–95)	100 (94–100)
23. How much has your enjoyment of life been limited by your knee problem?	70 (48–92)^‡	94 (83–100)	100 (98–100)
24. How often are you aware of your knee problem?	22 (2–75)^‡	53 (22–80)	95 (89–98)
25. Are you concerned about your knee with respect to lifestyle activities that you and your family do together?	53 (29–90)^‡	91 (66–100)	100 (90–100)
26. Have you modified your lifestyle to avoid potentially damaging activities to your knee?	37 (15–75)^‡	75 (45–94)	96 (81–100)
Social and emotional
27. Does it concern you that your competitive needs are no longer being met because of your knee problem?	47 (20–82)^‡	87 (42–100)	100 (91–100)
28. Have you had difficulty being able to psychologically “come to grips” with your knee problem?	82 (50–97)^§	95 (79–100)	100 (100–100)
29. How often are you apprehensive about your knee?	51 (34–88)^§	81 (50–98)	96 (84–100)
30. How much are you troubled with lack of confidence in your knee?	55 (31–88)^§	80 (50–100)	98 (92–100)
31. How fearful are you of reinjuring your knee?	36 (5–75)	45 (17–86)	86 (40–100)
Total ACL-QoL score	51 (37–71)^§	66 (50–82)	92 (81–98)

Abbreviations: ACL, anterior cruciate ligament; ACL-QoL, Anterior Cruciate Ligament Quality of Life questionnaire; ROA, radiographic osteoarthritis.

*Values are median (interquartile range). P values were obtained from the Mann-Whitney U test. The wording for some questions was shortened due to space limitations (see Mohtadi¹⁸ for precise wording).

^†One person from the asymptomatic group did not complete the ACL-QoL.

^‡P<.01.

^§P<.05.

Work-Related Concerns Symptomatic participants reported trouble with squatting motions at work, and ceiling effects were evident for other items (TABLE 2). There were no statistical differences in work-related concerns between symptomatic individuals with and without ROA (TABLE 2). All work-related concerns were worse in symptomatic participants with ROA (all items, P<.02) compared to asymptomatic individuals. The only item that did not differ between the groups was concern regarding loss of time from work due to knee treatment.

Recreational Activities and Sport Participation Compared to participants without ROA, participants with ROA reported worse athletic performance compared with preinjury performance, were more likely to play sport under caution, were more concerned with environmental conditions, found it difficult to go full out during sport, were more fearful of playing sport, and reported greater difficulties taking part in their second most important sport or activity (all, P<.05). Sport and recreational impairments had a greater impact on QoL for symptomatic participants with ROA (all items, P<.001) and without ROA (all items, P<.04) compared to asymptomatic individuals. Asymptomatic participants expressed concern that sport or recreational activity might result in worsening of their knee status (question 10 median, 64; IQR, 50–100), although they were less concerned than symptomatic individuals (with ROA: median, 27; IQR, 2–53; without ROA: median, 27; IQR, 12–65).

Lifestyle All items related to lifestyle factors were worse in symptomatic individuals with ROA, including concern with general safety issues, limitations in exercising and maintaining fitness, reduced enjoyment of life, more awareness of knee problems, greater knee concerns during family activities, and more lifestyle modifications. All lifestyle items were more impaired in symptomatic participants with ROA (P<.001) and without ROA (P<.05) compared to asymptomatic individuals.

Social and Emotional Social and emotional items were more impaired in symptomatic people with ROA, including concern that competitive needs were not being met, being apprehensive, difficulty coming to grips with knee problems, and worse knee confidence (TABLE 2). Social and emotional impairments were greater in symptomatic participants with ROA (P<.001) and without ROA (P<.03) compared to asymptomatic individuals.

Discussion

In individuals with knee symptoms more than 5 years after ACL reconstruction, ROA in the tibiofemoral and/or patellofemoral joint was related to worse knee-related QoL. Although health-related QoL was similar between symptomatic people with and without ROA, this was impaired compared to an asymptomatic ACL-reconstructed group. Exploring specific ACL-QoL items revealed aspects of QoL that were more impaired in symptomatic individuals with ROA, including sport and recreation limitations, lifestyle factors, and social/emotional difficulties.

Concerns about sport limitations were common for both symptomatic groups, and to a greater degree in people with ROA. Items that were more impaired in those with ROA included reduced sports performance, playing sport under caution, concern with sports environment, difficulty going full out, fear of contact sports, and limitations in preferred activities. Our previous study found that not returning to sport after ACL reconstruction was associated with worse QoL 5 to 20 years after ACL reconstruction in people with knee symptoms.⁹ Furthermore, ACL-QoL items surrounding sport have been rated of highest importance by a group of patients after ACL reconstruction.²⁹ Our qualitative research in this area also found that maintaining a satisfying, physically active lifestyle was a critical component of longer-term QoL after ACL reconstruction.¹¹ However, this is the first study to demonstrate the importance of sport participation among symptomatic people with ROA after ACL reconstruction.

Participants with ROA reported difficulty exercising and maintaining fitness due to their knee. Exercise and strength training are recommended as core treatments for reducing pain and improving function in people with knee osteoarthritis.¹⁷ Of concern is that 41% of participants with knee symptoms reported their osteoarthritis knowledge as poor or very poor (including 1 in 3 individuals with ROA), and only 20% were receiving treatment for their knee. The rehabilitation period provides an important opportunity for physical therapists to deliver osteoarthritis education and develop a long-term physical activity plan. While return to sport is a common goal of ACL rehabilitation, it is not known whether physical therapists discuss strategies for maintaining an active lifestyle across the lifespan. Additionally, symptomatic individuals with ROA commonly experienced poor knee confidence and reinjury fears. Addressing these potential barriers to physical activity may have positive impacts on QoL. There is a need to develop effective strategies to reduce fear of reinjury and improve knee confidence in symptomatic individuals after ACL reconstruction.

It is possible that difficulty exercising and maintaining fitness in symptomatic individuals with ROA after ACL reconstruction is greater for those with a strong preference for participation in competitive sports. Notably, people with ROA were more likely to express concern that their competitive needs were no longer being met due to their knee problem than were symptomatic people without ROA. We recently found that individuals with a strong preference to be active through competitive sport risked adopting an inactive lifestyle and experiencing reduced QoL if their knee limited them from pursuing sports activities.¹¹ Current osteoarthritis treatment recommendations largely target older patients³^,⁷ and, as such, may not address all aspects of importance to a symptomatic population with ROA after ACL reconstruction. Specifically, prioritizing sport participation, fulfilling competitive needs, and fear of reinjury may be largely unique to individuals after ACL reconstruction. For symptomatic individuals with ROA after ACL reconstruction who express a strong preference to be active through competitive sports, discovering activities that meet their competitive needs and do not exacerbate their knee symptoms or function could positively impact QoL. Modifications of team sports, such as walking football and walking netball, could provide appropriate alternatives to high-impact sports. Further research is needed to explore this possibility.

Our findings do not necessarily support the use of radiographs to diagnose knee osteoarthritis. Rather, they highlight the value in diagnosing ROA in symptomatic individuals after ACL reconstruction. Symptoms due to osteoarthritis should be managed differently from those unrelated to osteoarthritis. For example, recommended osteoarthritis management includes osteoarthritis education, physical activity pacing (small amounts often), weight loss, specialized footwear, walking aids, and joint replacement surgery for severe osteoarthritis.³^,⁷ These treatments may be inappropriate for symptomatic individuals without ROA after ACL reconstruction, further highlighting the value in diagnosing ROA in this population. Ideally, symptomatic osteoarthritis can be diagnosed through clinical assessment rather than by obtaining a knee radiograph, in line with European League Against Rheumatism guidelines.²⁷ However, imaging is recommended to help confirm alternative diagnoses, and there is a shortage of studies investigating the added benefit of imaging over clinical findings for diagnosing knee osteoarthritis.²⁷ Importantly, recommendations regarding use of imaging to diagnose osteoarthritis have not been made specifically for individuals after ACL reconstruction who may present with different knee symptoms compared with the typical population without ACL injury. Further research is needed to evaluate whether clinical assessment can accurately diagnose osteoarthritis in people with knee symptoms after ACL reconstruction.

We found less QoL impairment in the asymptomatic group (irrespective of ROA status) compared to symptomatic patients with and without ROA. This suggests that more knee symptoms may have a negative impact on QoL. To provide further information regarding whether pain and symptom severity alone could explain the difference in QoL between symptomatic groups with and without ROA, we performed a post hoc analysis. The ACL-QoL scores stratified by KOOS pain and KOOS symptoms severity are presented in the APPENDIX (available at www.jospt.org). Symptomatic individuals with ROA appeared to have worse QoL, with similar degrees of knee pain and symptoms, compared to symptomatic individuals without ROA. Notably, we could not determine the significance of any between-group difference due to insufficient power. Exploring differences in QoL between ROA and non-ROA groups, stratified by knee pain and symptom severity, could be an important area for future research.

Although sport limitations appear to be related to ROA 5 to 20 years after ACL reconstruction, few studies have investigated the relationship between return to preinjury sport (at any time after ACL reconstruction) and the development of ROA.² We found similar return-to-sport rates in symptomatic people with and without ROA after ACL reconstruction, and our previous investigations found that return to sport was not related to ROA in this sample.⁸ While this provides some evidence that returning to sport after ACL reconstruction may not be associated with ROA development, additional prospective research is required to explore this relationship further.

Strengths and Limitations

This is the first study to explore specific aspects of QoL in symptomatic individuals with and without ROA after ACL reconstruction, providing clinically applicable information that may be used to guide the development of strategies to improve longer-term QoL after ACL reconstruction. Additional strengths of this study include radiographing both the tibiofemoral and patellofemoral joints and including symptomatic and asymptomatic groups. Although the ACL-QoL contains many items of importance to individuals after ACL reconstruction and its psychometric properties have been previously evaluated,¹⁶ it was designed to address aspects of QoL relevant for ACL-deficient people with knee difficulties.¹⁸ Consequently, validity of this measure for use in individuals with knee difficulties 5 to 20 years after ACL reconstruction is unclear. We found that using the ACL-QoL in this sample resulted in potential item redundancy (very similar participant scores for items assessing similar aspects of QoL (eg, items 13 and 17, and items 29 and 30) and a ceiling effect for 5 items (1a, 1b, 5, 7, and 8), which suggests that these items may be inappropriate for use in people with knee symptoms more than 5 years after ACL reconstruction.

A limitation of this study was that only 50% of individuals from the parent study elected to undergo a knee radiograph. Despite similar characteristics between radiographed and nonradiographed individuals, the proportion of individuals choosing not to undergo a radiograph might impact the generalizability of results. For instance, these results may be less applicable to older individuals (ie, those who did not undergo radiographs were older on average) or those with less time to undergo a knee radiograph (not enough time was the most common reason for rejecting the invitation for knee radiography). Assuming a pooled standard deviation of 16 units on the ACL-QoL,¹⁶ we required 28 participants per group to achieve a power of 80% and a level of significance of 5% (2 sided) for detecting a true difference between groups of 12 units on the ACL-QoL. Due to the nature of recruitment, we were underpowered to detect true differences between groups of fewer than 12 units on the ACL-QoL.

Unfortunately, it was not practical for participants to complete the questionnaire at the time of radiography. Consequently, participants' pain and symptoms could have changed between questionnaire completion and radiography (median, 9 months). To assess this, a proportion of symptomatic participants (n = 56, 34%) recompleted the KOOS a mean ± SD of 12 ± 1 months (range, 10–18 months) after completing the previous questionnaire. Wilcoxon signed-rank tests indicate that KOOS pain, symptoms, and function subscale scores were all similar between these 2 time points (P .05 for all analyses), with no clinically relevant differences identified according to the minimal important change for this instrument.⁴ Notably, no validated criteria exist to define knee difficulties in individuals after ACL reconstruction, so we adapted criteria from a prior study. A limitation of using this approach was that individuals who did not meet these criteria (forming the “asymptomatic group”) could have experienced some knee difficulties (ie, impairment in 1 of the 5 KOOS subscales or slight impairment in more than 1 KOOS subscale). Additionally, the cross-sectional design only allowed us to examine associations rather than causal inferences.

Conclusion

Symptomatic individuals with ROA after ACL reconstruction experienced greater knee-related QoL impairment than symptomatic individuals without ROA. Health-related QoL was impaired in all symptomatic individuals after ACL reconstruction, irrespective of ROA status. We identified specific aspects of QoL that were impaired in symptomatic people with ROA, highlighting greater limitations and concern surrounding sport and exercise and social/emotional difficulties in this subgroup of individuals. It may be important to extend focus beyond return to sport, to include maintenance of a physically active lifestyle across the lifespan following ACL reconstruction. There may be benefit in diagnosing ROA in symptomatic individuals after ACL reconstruction, as these individuals may require different management from symptomatic individuals without ROA. Additionally, symptomatic individuals after ACL reconstruction with osteoarthritis may have unique needs that are not addressed in current osteoarthritis management guidelines.

Key Points

Findings

Symptomatic individuals after anterior cruciate ligament (ACL) reconstruction with radiographic osteoarthritis (ROA) experienced worse knee-related quality of life (QoL) than did symptomatic individuals after ACL reconstruction without ROA. Health-related QoL was impaired to a similar degree in people with knee symptoms compared to an asymptomatic group after ACL reconstruction. Specific aspects of QoL that were more impaired in symptomatic people with ROA included sport and exercise limitations, reduced enjoyment of life, family-related activity limitations, and emotional troubles.

Implications

There may be value in diagnosing osteoarthritis in symptomatic individuals after ACL reconstruction, as these individuals may require different management than symptomatic individuals after ACL reconstruction without osteoarthritis. Current osteoarthritis treatment recommendations may not address all aspects of importance to symptomatic individuals after ACL reconstruction with osteoarthritis. Personalized strategies to increase participation in preferred forms of exercise and enhance knee confidence may have potential to improve longer-term QoL in symptomatic people with osteoarthritis following ACL reconstruction.

Caution

The Anterior Cruciate Ligament Quality of Life instrument was designed to address aspects of QoL relevant for people with ACL injury and knee difficulties; as such, the instrument may not address all aspects of QoL relevant to individuals following ACL reconstruction with longer-term knee difficulties. The cross-sectional design only allowed us to examine associations rather than causal inferences.

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Appendix

**FIGURE 1.** ACL-QoL mean scores stratified by KOOS symptoms subscale quartiles. Error bars represent standard deviations. Quartiles were determined according to the distribution of KOOS symptoms subscale scores for all participants. The ACL-QoL and KOOS symptoms subscale are scored from 0 (worst) to 100 (best). Abbreviations: ACL-QoL, Anterior Cruciate Ligament Quality of Life questionnaire; KOOS, Knee injury and Osteoarthritis Outcome Score; ROA, radiographic osteoarthritis.

**FIGURE 2.** ACL-QoL mean scores stratified by KOOS pain subscale quartiles. Error bars represent standard deviations. Quartiles were determined according to the distribution of KOOS pain subscale scores for all participants. The ACL-QoL and KOOS pain subscale are scored from 0 (worst) to 100 (best). Abbreviations: ACL-QoL, Anterior Cruciate Ligament Quality of Life questionnaire; KOOS, Knee injury and Osteoarthritis Outcome Score; ROA, radiographic osteoarthritis.

Volume 48, Issue 5May 2018

Pages: 348-427

Keywords

Correspondence

Address correspondence to Dr Stephanie Filbay, University of Oxford, Botnar Research Centre, Windmill Road, Headington, Oxfordshire, UK OX3 7LD. E-mail: [email protected]

Disclosure

Ethical approval for this study was obtained from the University of Queensland Medical Research Ethics Committee (approval number 2012001240). Funding for this study was awarded by the Physiotherapy Research Foundation (seeding grant number S13-004). The authors certify that they have no affiliations with or financial involvement in any organization or entity with a direct financial interest in the subject matter or materials discussed in the article.

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Quality of Life in Symptomatic Individuals After Anterior Cruciate Ligament Reconstruction, With and Without Radiographic Knee Osteoarthritis

Abstract

Study Design

Background

Objectives

Methods

Results

Conclusion