1 Degree project, 30 ECTS 2020.08.26
Incidence of meniscal tears and cartilage lesions
at the time of anterior cruciate ligament
reconstruction in Region Örebro County
– a retrospective cohort study
Version 2.0Author: Joakim Dahlgren, Bachelor of medicine
School of Medical Sciences Örebro University Örebro Sweden
Supervisors: Per Wretenberg, MD, Professor in orthopedic surgery
Daniel Castellanos, MD, Orthopedic specialist, PhD Student Dept. of Orthopedics, Örebro University Hospital Faculty of Medicine and Health Örebro University Örebro Sweden Word count Abstract: 247 Manuscript: 3468
2
Abstract
Introduction: The anterior cruciate ligament (ACL) is a supporting ligament in the knee.
ACL injuries are associated with concomitant meniscal tears and cartilage lesions.
Aim: Our aim was to study the incidence of meniscal tears and cartilage lesions in patients
with ACL injury and how it varies with time from injury to surgery.
Methods: This was a cohort study using the Swedish Knee Ligament Registry. We reviewed
479 patients who had ACL reconstruction in Region Örebro County between 2005-01-01 and 2019-03-19.
Results: The incidence of meniscal tears was 33 %, cartilage lesions 18 %, both meniscal
tears and cartilage lesions 29 %. The incidence of meniscal tears distributed over time from injury to surgery was 8 % for 0-3 months., 38 % for 4-12 months, 53 % for > 12 months. The incidence of cartilage lesions was 8 % for 0-3 months, 45 % for 4-12 months, 47 % for > 12 months. The incidence of both meniscal tears and cartilage lesions was 4 % for 0-3 months, 34 % for 4-12 months, 62 % for > 12 months.
Conclusions: Patients treated with ACL reconstruction had an increased rate of concomitant
damage to menisci and articular cartilage with increased time from injury to surgery, suggesting a benefit of early reconstructive interventions following an ACL injury. Male patients displayed a higher incidence in cartilage lesions than did female. Young age was associated with a higher incidence of meniscal tears, whereas an increasing of age was associated with an increased incidence of cartilage lesions.
Keywords: Registry; anterior cruciate ligament (ACL); reconstruction; meniscal tears;
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Abbreviations
ACL Anterior cruciate ligament
ACL-R Anterior cruciate ligament reconstruction PCL Posterior cruciate ligament
MCL Medial collateral ligament LCL Lateral collateral ligament PLC Posterolateral corner RÖL Region Örebro County
SKLR Swedish Knee Ligament Registry ICRS International Cartilage Repair Society Yr. Year(s)
Mos. Months
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Introduction
The knee is one of the strongest and most complex joints in the human body and allows for movement of the lower leg while supporting the body’s weight [1]. The knee joint lack a deep concave socket, and from the perspective of structural fit, therefore, the knee is relatively unstable. Strong ligaments are therefore required to provide joint stability.
There are four major ligaments that maintain proper alignment and stability of the knee. The medial collateral ligament (MCL) and lateral collateral ligament (LCL) prevents valgus and varus deformation, respectively. The anterior cruciate ligament (ACL) plays an important role in preventing hyperextension of the knee by limiting anterior translation of the tibia. Likewise, the posterior cruciate ligament (PCL) limits posterior translation.
The knee contains the medial and lateral menisci, two crescent shaped fibrocartilaginous discs facilitating structural fit and improving joint congruency, further stabilizing the joint [2]. They also absorb and dissipate compressive forces transferred across the joint and help reduce friction. The menisci are susceptible to damage from torsion or hyperextension of the knee. Once injured, the menisci may not heal well because of its poor blood supply.
The joint surfaces of each bone in the knee are covered in a layer of cartilage that provide a smooth gliding surface [3]. The articular cartilage is resilient and function as a cushion where bone ends meet, protecting underlying bone. If the cartilage is damaged, the joint surfaces may no longer be smooth and bones may rub against each other, causing friction. Friction can cause inflammation and may ultimately lead to osteoarthritis. Given that chondrocytes have limited repair capabilities and articular cartilage being avascular, damage is difficult to heal. Cartilage damage is graded according to theInternational Cartilage Repair Society (ICRS) [4,5]. Grade 1, nearly normal: superficial lesions, soft indentation, and/or superficial fissures and cracks. Grade 2, abnormal: lesions extending down to <50% of cartilage depth. Grade 3, severely abnormal: cartilage defects extending down >50% of cartilage depth as well as down to calcified layer. Grade 4, severely abnormal: osteochondral injuries, lesions extending just through the subchondral bone plate, or deeper defects down into trabecular bone.
Since knee ligaments are necessary to maintain structural stability in the knee, tearing of any may render the knee unstable in certain situations [6]. This holds especially true for the ACL, being the most commonly injured ligament in the knee with an annual incidence of
approximately 80 per 100 000 within the population of Sweden [7]. An unstable knee due to an ACL injury is in turn associated with concomitant damage to menisci and cartilage [8–10].
5 Also, there is an increased risk of developing early onset osteoarthritis of the knee with ensuing disability later in life following an ACL injury, regardless of treatment. Indeed, at 10 to 20 years after an ACL injury, 50 % of patients have developed osteoarthritis of the knee with associated pain and functional impairment [11–13].
Depending on their severity, ACL injuries are managed conservatively with physiotherapy or with surgery. A completely torn ACL will not heal by itself and therefore not regain its structural properties. For surgical intervention, therefore, ACL reconstruction (ACL-R) is standard procedure [14,15]. In Sweden, a total of 3763 patients underwent ACL-R in 2018 [7]. Thus, approximately half of all ACL injuries are treated surgically. Interestingly, a recent systematic review and meta-analysis by Mehl et al. [16] have shown a positive
correlation between rate of injuries of menisci and articular cartilage and time from injury to surgery.
Aim
Our aim was to evaluate the incidence of meniscal tears and cartilage lesions at the time of ACL-R as well as the incidence of meniscal tears and cartilage lesions in relation to time from injury to surgery.
1. What is the incidence of meniscal tears at the time of ACL-R in RÖL? 2. What is the incidence of cartilage lesions at the time of ACL-R in RÖL?
3. How does incidence of meniscal tears and cartilage lesions vary with time from injury?
Materials and methods
Study design
A retrospective cohort study.
Study population
Data from patients operated with ACL-R in Region Örebro County was extracted from the Swedish Knee Ligament Registry (SKLR) between 2005-01-01 and 2019-03-19.
Data collection
Since 2005, the SKLR have annually monitored patient data regarding interventions and outcome after interventions following an ACL injury. Approximately 90 % of all ACL-R performed in Sweden are included in this register [7]. Preoperative and perioperative data is
6 registered by the surgeon preforming the ACL-R regarding concomitant injury to menisci and/or cartilage. Since the SKLR has until recently only been a surgical registry, only patients undergoing ACL-R were included, therefore no control group were included in this study. Preoperative patient details were obtained including age at time of surgery, sex, previous surgery, date of injury and date of surgery, location of meniscal tears if present, and location and grading of cartilage lesions if present. Meniscal tears were assessed by checking registry data for patients with either lateral or medial meniscal tear, or both. The same applied for cartilage lesions. Cartilage lesions were assessed by checking registry data for patients with intra-articular damage to any of the following structures: medial patella, lateral patella, trochlea, medial femur condyle, medial tibial plateau, lateral femur condyle and lateral tibial plateau. Cartilage lesions were graded according to theICRS grading system. For the purpose of this analysis, the seven locations of cartilage damage and the two locations of meniscal damage were combined into either any cartilage or any meniscal injury.
Exclusion criteria was incomplete registry data, surgical revisions and multiligament knee injuries.
The patients were divided into four age groups according to their age at the time of surgery: 15 to 19 years; 20 to 24 years; 25 to 29 years; and 30 years and older. The age categories were established, as has been done in former literature (Granan et al), in order to account for the natural incidence of injury to menisci and articular cartilage as well as the process of degeneration that differs between young and older adults [3,17]. Categorization for sex was also done, as the incidence of injury to menisci and articular cartilage could be expected to differ between sexes.
Time from injury was assessed by calculating the time in months between knee injury and ACL-R. Patients were placed into categories based on their time from injury: 0-3, 4-12, and 12 months. The time categories were based on former literature analyzing differences in meniscal and cartilage injuries [19], as well as patient reported outcome and return to sports [20]. For some patients, registry data did not provide the exact date of injury. This was due to the patient failing to remember so when consulting the orthopedic surgeon handling the registry form. If so, the month and/or year were instead specified in the registry. If the day of the month could not be assessed from the registry data but the month and year could, then the first day of the month was set as a default. If the month of injury could not be assessed, then the data was counted as incomplete.
7 Even if the vast majority of injuries in the SKLR are ACL injuries, multiligament knee
injuries and isolated injuries to other ligaments in the knee are also registered. We limited our assessment to isolated ACL injuries since multiligament knee injuries constitutes a complex entity by itself. The definition of a multiligament knee injury was concomitant ligament injury to either the PCL, MCL, LCL or the posterolateral corner (PLC), i.e. the same definition as the SKLR used in their latest annual report (2018) [7].
Statistics
Pearson’s Chi-square test was used for each of our analysis, since our data was categorical nominal or ordinal. A p-value of 0.05 or less was considered to be statistically significant. All statistical analyses were performed using SPSS version 26.0
Ethics
This study was conducted as a quality control register study, meaning there was no direct involvement with any of the patients concerned. The director of the Department of
Orthopedics approved of the study beforehand. All data from the registry were coded. The key code was stored in the Orthopedic department vault and could only be accessed daytime with permission of a supervisor in case of further need to look into patient’s data. All the results were presented in a way so that the individual patient could not be identified or traced. This study will not be published.
8 FIGURE 1
Patient distribution and exclusion criteria.
a ACL, anterior cruciate ligament.
b Medial collateral ligament, lateral collateral ligament, posterior cruciate ligament, posterolateral corner.
Results
Patient demographics
There were a total of 554 patients undergoing ACL-R in Region Örebro County from the 1st January 2005 until the 19th Mars 2019. A flowchart illustrating the patient distribution and exclusion criteria is shown in Figure 1. A total of 75 patients were excluded because of incomplete data, surgical revisions or because they were classified as multiligament injuries. A total of 479 patients were left after the exclusion and were divided in four groups: isolated ACL injuries, ACL injuries and meniscal injuries, ACL injuries and cartilage injuries, and ACL injuries with both meniscal and cartilage injuries. The number of patients, sex and distribution of meniscal and cartilage lesions across age groups are shown in Table 1.
Primary ACLa reconstructions n = 524 ACL injury + meniscal tear + cartilage lesion n = 141 ACL injury + meniscal tear n = 159 ACL injury + cartilage lesion n = 86 Isolated ACL injury
n = 93
Included in the study n = 479 Excluded: Multiligament injuriesb n = 20 Incomplete registry data n = 25 Excluded: Surgical revisions n = 30 All ACL reconstructions n = 554
9 TABLE 1
Patient characteristics and injury distribution at the time of primary ACL reconstructiona Age Group, yr.
15-19 (n = 152) 20-24 (n = 114) 25-29 (n = 88) ≥ 30 (n = 125) Characteristic n % n % n % n %
Previous knee surgery 35 23 29 25 23 26 50 40
Sex
Male 63 41 68 60 64 73 77 62
Female 89 59 46 40 24 27 48 38
Type of injury
Isolated ACL injury 30 20 35 31 10 11 18 14
Meniscal tear 67 44 37 32 31 35 24 19
Cartilage lesion 13 9 17 15 19 22 37 30
Both meniscal tear and cartilage lesion
42 28 25 22 28 32 46 37
Meniscal tear location
No tear 43 28 52 46 29 33 55 44 Medial only 40 26 22 19 22 25 30 24 Lateral only 44 29 25 22 20 23 23 18 Both 25 16 15 13 17 19 17 14 ICRS grading No cartilage injury 97 64 72 63 41 47 42 34 Grade 1 29 19 22 19 22 25 30 24 Grade 2 22 14 17 15 20 23 37 30 Grade 3 3 2 3 3 5 6 7 6 Grade 4 1 1 0 0 0 0 9 7
Time from injury
0-3 months 13 9 5 4 4 5 7 6
4-12 months 68 45 50 44 39 44 38 30
> 12 months 71 47 59 52 45 51 80 64
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Meniscal tears and cartilage lesions
Out of all ACL patients included in the study, the incidence of meniscal tears was 33 % (95 % confidence interval [CI], 29-38 %), cartilage lesions 18 % (95 % CI, 15-22 %), and both meniscal tears and cartilage lesions 29 % (95 % CI, 25-34 %). The total incidence of
meniscal tears was 63 % (95 % CI, 58-67 %) and the total incidence of cartilage lesions was 47 % (95 % CI, 43-52 %).
Meniscal tears were distributed in two locations: the medial meniscus and/or the lateral meniscus, i.e. one patient could have more than one meniscal tear in the same knee. There were a total of 300 patients with meniscal tears. Out of all patients with meniscal tears, 38 % (95 % CI, 33-44 %) had a tear in their medial meniscus, 37 % (95 % CI, 32-43 %) had a tear in their lateral meniscus, and 25 % (95 % CI, 20-30 %) had tears in both their medial and lateral menisci. A diagram illustrating meniscal tear distribution for all patients with meniscal tears is shown in Figure 2.
FIGURE 2
Meniscal tear location for all ACL patients with meniscal tearsa
a Data expressed as No.
Medial meniscus 114
Lateral meniscus 112 Medial and lateral
menisci 74
11 Cartilage lesions were distributed in up to seven different locations in the knee, i.e. one ACL patient could have more than one cartilage lesion. There were a total of 227 patients with cartilage lesions. Among these patients, a total of 519 cartilage lesions were recorded. There was an average of 2.3 cartilage lesions per patient. The most common lesion location was the medial femur condyle representing 34 % of all cartilage lesions (95 % CI, 30-39 %). Partial thickness cartilage lesions (ICRS grade 1-2) was the most common lesion type representing 88 % of all cartilage lesions (95 % CI, 83-92 %). A diagram illustrating lesion location and ICRS grade for all cartilage lesions is shown in Figure 3.
FIGURE 3
Lesion location and ICRS grade distribution for all ACL patients with cartilage lesionsa
a Data expressed as No.; ICRS, International Cartilage Repair Society. Grade 1, nearly normal: superficial
lesions, soft indentation, and/or superficial fissures and cracks. Grade 2, abnormal: lesions extending down to <50% of cartilage depth. Grade 3, severely abnormal: cartilage defects extending down >50% of cartilage depth as well as down to calcified layer. Grade 4, severely abnormal: osteochondral injuries, lesions extending just through the subchondral bone plate, or deeper defects down into trabecular bone.
28 14 16 80 74 37 57 10 3 6 77 43 21 18 1 2 2 13 5 1 1 0 0 1 8 0 1 0 0 20 40 60 80 100 120 140 160 180 200
Medial patella Lateral patella Trochlea Medial femur
condyle Medial tibial plateau Lateral femur condyle Lateral tibial plateau
12 Out of all male ACL patients, 84 patients had meniscal tears only, 54 patients had cartilage lesions only, and 87 patients had both meniscal tears and cartilage lesions. Out of all female patients, 75 patients had meniscal tears only, 32 patients had cartilage lesions only, and 54 patients had both meniscal tears and cartilage lesions.
The difference in incidence of meniscal tears between sex was not statistically significant (p = 0.48, 95% CI). However, there was a statistically significant difference in incidence of cartilage lesions between males with 63% and females with 37% (p = 0.018, 95% CI). This was also the case with patients suffering from both meniscal tears and cartilage lesions, with males have an incidence of both meniscal and cartilage lesions of 62 % compared to 38 % in females (p = 0.005, 95% CI). The incidence of meniscal tears and cartilage lesions for all patients distributed over sex are shown in Figure 4, Panel A.
The ACL patients within the age group of 15-19 years displayed the highest incidence of meniscal tears with 42 % compared to all other age groups (p < 0.001, 95% CI). Conversely, patients within the age group of ≥ 30 years displayed the highest incidence of cartilage lesions with 43 % compared to all other age groups (p = 0.001, 95% CI). Out of all patients suffering from both meniscal tears and cartilage lesions, patients within the age group of ≥ 30 displayed the highest incidence; Compared to patients within the age group of 15-19 years, however, the difference was not statistically significant (p = 0.67, 95% CI). The incidence of meniscal tears and cartilage lesions for all patients distributed over age group are shown in Figure 4, Panel B.
13 FIGURE 4
Panel A: Incidence of meniscal tears and cartilage lesions for all ACL patients distributed over sex a
Panel B: Incidence of meniscal tears and cartilage lesions for all ACL patients distributed over age a
a Data expressed as percent (%).
0 10 20 30 40 50 60 70
Meniscal tear Cartilage lesion Both meniscal tear and cartilage
lesion Male Female 0 5 10 15 20 25 30 35 40 45 50
Meniscal tear Cartilage lesion Both meniscal tear and cartilage
lesion
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Meniscal and cartilage injury and time of surgery from injury
The time of surgery from injury varied between 0 to 252 months. The median time of surgery from injury was 14 months. Out of those with time of surgery from injury being 0-3 mos., 13 had meniscal tears, 7 had cartilage lesions, and 6 had both meniscal tears and cartilage lesions. Likewise, out of those with time from injury being 4-12 mos., 61 had meniscal tears, 39 had cartilage lesions, and 48 had both meniscal tears and cartilage lesions. Out of those with time of surgery from injury being > 12 mos., 85 had meniscal tears, 40 had cartilage lesions, and 87 had both meniscal tears and cartilage lesions.
Patients with time of surgery from injury being 0-3 months displayed an incidence of 8 % in meniscal tears, which was significantly lower compared to 4-12 months with 38 % (p < 0.001, 95% CI) and > 12 months with 53 % (p < 0.001, 95% CI). Patients with time of surgery from injury being 0-3 months also displayed an incidence of 8 % in cartilage lesions, which was significantly lower compared to 4-12 months with 45 % (p < 0.001, 95% CI) and > 12 months with 47 % (p <0.001, 95% CI). The incidence of both meniscal tears and cartilage lesions was 4 % in the group of patients with time of surgery from injury being 0-3 months, which was significantly lower compared to 4-12 months with 34% (p < 0.001, 95% CI) and > 12 months with 62 % (p < 0.001, 95% CI). The time of surgery from injury distributed over type of injury is shown in Figure 5.
Figure 5
Time from injury for all ACL patients distributed over type of injurya
a Data expressed as percent (%).
0 10 20 30 40 50 60 70
Meniscal tear Cartilage lesion Both meniscal tear and cartilage
lesion
15
Discussion
Tearing of the ACL is a common and often challenging injury. The treatment always starts with physiotherapy, but many patients are also operated with ACL reconstruction [21]. ACL injuries are often associated with other injuries such as meniscal tears and cartilage lesions [8–10]. These associated injuries are important for the prognosis of the main injury, the ACL tear, and therefore it is important to know how many patients that also suffer from these associated injuries. The aim of our study was to evaluate the incidence of meniscal tears and cartilage lesions in RÖL, as well as to study how these associated injuries may vary with time from injury to surgery in RÖL.
Out of all patients with meniscal tears, 38 % had a tear in their medial meniscus, 37 % had a tear in their lateral meniscus, and 25 % had tears in both menisci. Since the medial meniscus has less mobility than the lateral, the medial meniscus is expected to be more susceptible to tearing [22]. In our study, however, this was not the case when measuring the incidence of both. There was but a marginal difference in distribution of tears between the medial and lateral meniscus. This finding is supported by Smith et al. [23] who demonstrated no statistically significant difference in incidence of medial and lateral meniscal tears in ACL deficient knees in their prospective analysis of 575 ACL injuries. An explanation to this may be because the incidence of medial and lateral meniscal tears in ACL deficient knees seems to vary depending on time from injury. Several published studies on ACL injuries have reported a predominant incidence of lateral meniscal tears in the acute phase following a knee injury [23–25]. The incidence of medial meniscal tears, on the other hand, have been shown to gradually increase with time from injury in ACL deficient knees, possibly due to chronic instability and repetitive events of giveaway of the knee.
Røtterud et al. [26] reported on the cartilage lesions observed in 8476 patients undergoing ACL-R between 2005 and 2008. Our findings are in line with their report. The most common lesion location was the medial femur condyle, representing 34 % of all lesions.
Partial-thickness cartilage lesions were the most common lesion type representing 88 % of all lesions.
There was a higher total incidence of cartilage lesions for male subjects compared to female. This is supported by Slauterbeck et al. [27] who attempted to relate the patient sex and age to the frequency of meniscal tears and cartilage lesions seen at the time of ACL-R. Several other studies have also shown that male sex is a risk factor associated with a greater incidence of
16 cartilage lesions [28,29]. Patients with male sex also constituted most cases of meniscal tears. However, the difference in incidence of meniscal tears between sex was not statistically significant in our study. Patients within the age group of 15-19 years displayed the highest incidence of meniscal tears with compared to all other age groups. On the contrary, the incidence of cartilage lesions instead increased with age. Indeed, an increase in incidence of cartilage lesions with older age have been demonstrated by previously mentioned reports recounting for factors related to concomitant damage to menisci and articular cartilage with ACL injury [28,29].
A systematic review and meta-analysis by Mehl et al. [16] demonstrated a correlation between timing of ACL-R and increased incidence of cartilage lesions and meniscal tears. This was also the case in our findings. There was a statistically significant higher incidence of meniscal tears and cartilage lesions in the group of patients with time from injury being 4-12 months and > 12 months compared to the group of patients with time from injury being 0-3 months. This is also supported by Granan et al. [30], demonstrating an increase of frequency of concomitant damage to menisci and articular cartilage following an increase of surgical delay. It is important to note that with the clinical practice in RÖL, patients with suspected meniscal injury are prioritized so that surgery can be performed as soon as possible. This is to reduce the risk of additional intra-articular damages caused by delay and is usually performed within a month after the initial insult to the knee. The higher incidence of meniscal tears and cartilage lesions following an increase of time from injury may be due to an unstable knee joint. Current literature postulates that following an ACL injury, an alteration in the mechanics of the knee can lead to adverse forces causing injury to menisci and articular cartilage over time [31].
It is important to note that this study has several limitations. We have not adjusted for
possible confounding factors. As mentioned above, sex is a determining factor in incidence of cartilage lesions and it logical to assume that this could be a confounder when analyzing the prevalence of cartilage lesions and time from injury to surgery. Age may also be a
confounder when assessing the prevalence of cartilage lesions since young patients are expected to differ from adults due to skeletal immaturity, and older patients are expected to differ from young adults due to the natural process of degenerative changes in the knee [3,17,32]. The patient’s weight and activity level may also bias the results, as both of these are risk factors known to increase the incidence of meniscal tears and cartilage lesions [33– 35]. Unfortunately, neither of these is a part of SKLR registry data. Previous surgeries can
17 also affect the outcome of our results as it is known that previously performed meniscectomy contributes to accelerated articular cartilage damage of the knee [36]. We suggest therefore that further studies be done in the future taking these measures into account.
Conclusions
Our findings show that ACL patients treated with reconstructive surgery have an increased rate of concomitant damage to menisci and articular cartilage with increased time from injury to surgery. This suggests a benefit of early reconstructive interventions following an ACL injury. Male patients displayed a higher incidence in cartilage lesions than did female. This prompts the question as to why this correlation is made and calls for further studies in the field. Young age was associated with a higher incidence of meniscal tears, whereas older patients displayed a higher incidence of cartilage lesions. How age relates to time from injury to surgery remains less understood and we suggest therefore that this is considered in future studies.
18
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[35] Wearing SC, Hennig EM, Byrne NM, Steele JR, Hills AP. Musculoskeletal disorders associated with obesity: a biomechanical perspective. Obes Rev 2006;7(3):239–50. [36] McDermott ID, Amis AA. The consequences of meniscectomy. J Bone Joint Surg Br
21
Populärvetenskaplig sammanfattning
Det främre korsbandet i knäleden är nödvändig för strukturell stabilitet i knät. Ett skadat främre korsband uppkommer typiskt vid vridvåld i knät och kan initialt ge upphov till plötslig smärta, svullnad och svårigheter att stödja på benet. Efter några dagar eller veckor gör det inte lika ont längre och svullnaden har gått ned. Då är det istället vanligt att knät känns ostadigt och att det viker sig. Fysioterapi spelar en central roll i behandlingen för att bli frisk igen. Ibland kan man också behöva opereras. Operationen går ut på att ta bort det trasiga korsbandet för att sedan ersätta det med en sena från benet som fästs i knät. I samband med operationen ser man ibland skador på menisk och ledbrosk. Skador i dessa strukturer ökar risken att senare i livet utveckla artros i samma led. Syftet med denna studie var att undersöka hur ofta dessa skador föreligger i Region Örebro Län samt hur de hänger samman med tiden mellan skada och operation.
Vi använde oss av det Svenska Korsbandsregistret som startades den 1 januari 2005 för att samla all nödvändig information. Vi kom fram till att den totala incidensen för meniskskador är 63 %, och den för broskskador 47 %. Tiden mellan skada och operation verkar spela roll eftersom dessa skador är signifikant färre ifall tiden mellan skada och operation inte
överstiger 3 månader jämfört med om man väntar längre tid. Fler studier behövs för att utröna hur dessa fynd förhåller sig till andra faktorer som vi inte undersöker i vår studie.
22
Cover letter
Acta Orthopaedica
Department of Orthopedics Lund University Hospital 221 85, Lund, Sweden Dear Editor,
We are sending you the manuscript of our study titled “Incidence of meniscal and cartilage lesions at the time of anterior cruciate ligament reconstruction in Region Örebro County”. We are interested in having the manuscript reviewed for publication in Acta Orthopaedica. This is a quality control retrospective register study using the Swedish Knee Ligament Registry. We assessed the incidence of meniscal and cartilage lesions among patients treated surgically with ligament reconstruction of the anterior cruciate ligament between 2005-01-01 and 2019-03-19. We stratified the incidence according to previous surgery, sex, age, type of injury and time from injury. In conclusion, our study shows that out of all patients that undergo ACL-R in RÖL, 63 % have meniscal tears and 47 % have cartilage lesions. There was a significantly lower incidence of meniscal tears and cartilage lesions with patients having to wait up to three months from injury compared to those who waited longer. We believe these findings would appeal to the editorial board and readership of Acta Orthopaedica.
We can confirm this manuscript has not been published elsewhere and is not reviewed by any other journal.
We are looking forward to your reply.
Warm regards,
Joakim Dahlgren, Bachelor of medicine.
School of medicine, Faculty of science and health, Örebro University Södra Grev Rosengatan 30, 703 62 Örebro, Sweden
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Etisk reflektion
Studien var en retrospektiv registerstudie med syfte till kvalitetssäkring och genomfördes utan inblandning av någon av de berörda patienterna. Studien godkändes av chefen för den Ortopediska kliniken i Region Örebro Län på förhand. All information från registret var kodad och nyckeln förvarades i den Ortopediska klinikens valv och kunde endast förfogas över dagtid med tillstånd av handledare om behov fanns att eftersöka patientinformation. Studiens resultat presenterades på ett sätt så att individuella patienter inte kunde bli identifierade eller spårade. Studien kommer inte att publiceras.
Patienterna som inkluderades i studien blev inte tillfrågade att delta. Detta kan man dryfta om som ett potentiellt hot mot autonomiprincipen. Dock är registreringen i det Svenska
Korsbandsregistret frivillig för varje enskild patient. Patienten ska alltid tillfrågas om hen vill att information om deras operation ska registreras eller inte. Om patienten inte önskar att bli registrerad i registret så har patienten rätt till att avstå. Om patienten önskar att ta bort redan befintlig information i registret så finns även möjlighet till detta. Studien genomfördes i enlighet med principen att göra gott då syftet var att kvalitetssäkra arbetet som genomförs på ortopediska kliniken i Region Örebro Län.
