Rasch analysis of the Knee injury and Osteoarthritis Outcome Score (KOOS): a statistical re-evaluation

The knee injury and Osteoarthritis Outcome Score (KOOS), based on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), is widely used to evaluate subjective outcome in anterior cruciate ligament (ACL) reconstructed patients. However, the validity of KOOS has not been assessed using Rasch analysis. The objective of this study was to evaluate the viability of KOOS as an outcome measure for ACL reconstruction using the partial credit Rasch model. Rasch analysis was applied to 200 KOOS questionnaires completed by patients consecutively tested 20 weeks after ACL reconstruction and subsequent rehabilitation. Rasch analysis showed that of the five proposed subscales in KOOS, only knee-related quality of life (QoL) and sport and recreational related function (Sport/Rec) fulfilled the criteria of a unidimensional measurement scale when applied to these patients. The three subdomains in KOOS extracted from WOMAC did not fulfill these criteria. While the content of KOOS appears to be relevant for knee patients, the psychometric measurement properties of KOOS are insufficient for use on patients 20 weeks subsequent to ACL reconstruction. A new knee measure targeted for these patients could be developed based on the content of KOOS. This study demonstrates that knee measurement instruments constructed for a specific condition cannot necessarily be used on patients with other similar conditions.     

Self‐reported previous knee injury and low knee function increase knee injury risk in adolescent female football

Knee injuries are common in adolescent female football. Self‐reported previous knee injury and low Knee injury and Osteoarthritis Outcome Score (KOOS) are proposed to predict future knee injuries, but evidence regarding this in adolescent female football is scarce. The aim of this study was to investigate self‐reported previous knee injury and low KOOS subscale score as risk factors for future knee injuries in adolescent female football. A sample of 326 adolescent female football players, aged 15–18, without knee injury at baseline, were included. Data on self‐reported previous knee injury and KOOS questionnaires were collected at baseline. Time‐loss knee injuries and football exposures were reported weekly by answers to standardized text‐message questions, followed by injury telephone interviews. A priori, self‐reported previous knee injury and low KOOS subscale scores (< 80 points) were chosen as independent variables in the risk factor analyses. The study showed that self‐reported previous knee injury significantly increased the risk of time‐loss knee injury [relative risk (RR): 3.65, 95% confidence (CI) 1.73–7.68; P < 0.001]. Risk of time‐loss knee injury was also significantly increased in players with low KOOS subscale scores (< 80 points) in Activities of Daily Living (RR: 5.0), Sport/Recreational (RR: 2.2) and Quality of Life (RR: 3.0) (P < 0.05). In conclusion, self‐reported previous knee injury and low scores in three KOOS subscales significantly increase the risk of future time‐loss knee injury in adolescent female football.     

Predictive factors for 12‐month outcome after anterior cruciate ligament reconstruction

There is a lack of knowledge regarding predictive factors for a successful clinical outcome after an anterior cruciate ligament (ACL) reconstruction. The aim was to investigate pre‐operative factors that may predict good outcomes as measured with the subscales Function in sports and recreation and Quality of life in Knee injury Osteoarthrithis Outcome Score (QOL‐KOOS), one‐leg hop test and Tegner Activity Scale 12 months after ACL reconstruction. Sixty‐four patients, operated with either patellar or hamstring tendon graft, were included. Demographics, range of motion, anterior knee laxity, pivot shift, muscle‐torques, anterior knee pain (AKP) and knee function were registered pre‐operatively and used in a multiple regression model. Results show less degree of AKP and low influence on knee function to be the most important predictors for good outcome in Sport/Rec‐KOOS (explained 31% of variances). Less AKP was in addition the most important predictor for QOL‐KOOS (14%). Patellar‐tendon graft, in favor of hamstring tendon graft, explained 8% of the improvement in the Tegner Activity Scale. In conclusion, a low degree of AKP was found to be the most important predictor for good clinical outcome 12 months after ACL reconstruction. Future studies, including psychological parameters, should use analyses that have the potential to control for independency between variables.     

Self-efficacy of knee function as a pre-operative predictor of outcome 1 year after anterior cruciate ligament reconstruction

The knee self-efficacy scale (K-SES) has been shown to have good reliability, validity and responsiveness during rehabilitation for patients' perceived self-efficacy of knee function. Determinants of self-efficacy of knee function 1 year after ACL reconstruction have been found to be the patients' internal locus of control and knee symptoms in sports and recreation. The predictive ability of perceived self-efficacy of knee function measured by the K-SES has not been studied in terms of patient outcome after an ACL reconstruction. The purpose of this study was to explore the potential for pre-operative self-efficacy of knee function measured by the K-SES to predict patient outcome in terms of physical activity, knee symptoms and muscle function 1 year after an ACL reconstruction. Thirty-eight patients were evaluated for outcome in terms of physical activity with the Tegner activity scale and the physical activity scale (PAS), knee symptoms with the Lysholm knee scoring scale and the knee injury and osteoarthritis outcome score (KOOS) and knee function with ability tests for muscle function 1 year after ACL reconstruction. Multiple regression and logistic multiple regression analysis were used to evaluate the K-SES as a possible predictor of outcome. The patients' present perceived self-efficacy of knee function (K-SES(Present)) pre-operatively was a significant predictor (P = 0.016) of the patients returning to their intensity and frequency of physical activity (PAS) 1 year after ACL reconstruction, when adjusted for age, gender and pre-injury physical activity level (Tegner(Pre-injury)) (odds ratio = 2.1). The patients' perceived future self-efficacy of knee function (K-SES(Future)) pre-operatively was a significant predictor (P = 0.045) of their self-rated knee function in sports/recreational activities (KOOS(Sports/recreation)) at the 1-year follow-up, when adjusted for age, gender and Tegner(Pre-injury )(R (2 )=0.25). The pre-operative K-SES(Future) was also a significant predictor (P = 0.023) of the patients' knee-related quality of life (KOOS(Qol)), at the 1-year follow-up, when adjusted for age, gender and Tegner(Pre-injury) (R (2 )=0.23). The pre-operative K-SES(Future) was furthermore a significant predictor of an acceptable outcome 1 year after surgery, on the Lysholm knee scoring scale (P = 0.003, odds ratio = 1.7), as well as on KOOS(Sports/recreation) (P = 0.002, odds ratio = 1.6) and knee-related quality of life (KOOS(Qol)) (P = 0.037, odds ratio = 1.4), when adjusted for age, gender and Tegner(Pre-injury). The pre-operative K-SES(Future) was also a significant predictor (P = 0.04) of an acceptable outcome 1 year after surgery, on the one-leg hop for distance (odds ratio = 2.2), when adjusted for age, gender and Tegner(Pre-injury). In conclusion, this study indicates that patients' perceived self-efficacy of knee function pre-operatively is of predictive value for their return to acceptable levels of physical activity, symptoms and muscle function 1 year after ACL reconstruction.     

Reliability, validity and responsiveness of the Spanish version of the Knee Injury and Osteoarthritis Outcome Score (KOOS) in patients with chondral lesion of the knee

Purpose

The purpose of this study was to perform a cross-cultural adaptation of the Knee Injury and Osteoarthritis Outcome Score (KOOS) into Spanish and to evaluate the psychometric properties of this version in patients with chondral lesion of the knee, as expressed by its validity, reliability and responsiveness.

Methods

The translation followed an established forward–backward translation procedure with independent translations and counter-translation, according to the recommendations for the cross-cultural adaptation of HRQL measures. Twenty Spanish-speaking patients who underwent arthroscopic surgery for knee cartilage defects with a microfracture technique were enroled in the study. Diagnosis was made based on clinical criteria and radiological confirmation through magnetic resonance imaging. Patients showing signs of instability, axial malalignment or generalised knee osteoarthritis were excluded from the study.

Results

Cronbach’s alpha value for the study of the questionnaire was >0.7 in all the KOOS domains except for Symptoms domain. The test–retest reliability was confirmed with an ICC value greater than 0.8 in all the KOOS domains. A significant agreement between the KOOS domains and the scales of the SF-36 with related content, particularly in the areas of physical function and pain, was observed.

Conclusion

Spanish KOOS questionnaire is valid, reliable and responsive for use in Spanish patients with symptomatic chondral lesion of the knee receiving surgical intervention.

Level of evidence

IV.     

Full-thickness cartilage lesion do not affect knee function in patients with ACL injury

There is debate in the literature regarding the impact of full-thickness cartilage lesion on knee function in patients with ACL injury. The hypothesis of the current study is that a full-thickness cartilage lesion at the time of ACL reconstruction does not influence knee function as measured by the Knee injury and Osteoarthritis Outcome Score (KOOS) in patients with ACL injury. Of the 4,849 primary ACL surgery cases in the Norwegian National Knee Ligament Registry as of 12 December 2007, 30 patients met the following inclusion criteria: a full-thickness cartilage lesion (International Cartilage Repair Society [ICRS] grades 3 and 4), age less than 40 years, no associated pathology or meniscus injury, and less than 1 year between knee injury and ACL reconstruction. Each of the 30 patients in this study group was matched with two control participants without cartilage lesions. Preoperatively, the patients completed the KOOS, and the surgeon recorded the location and size of the cartilage lesion and graded the cartilage injury according to ICRS standards. There were no significant differences between the case and control groups for any of the five subscales of the KOOS. A cartilage lesion was located in the medial compartment in 67% of the cases, in the lateral compartment in 20% of the cases, and in the patellofemoral joint in 13% of the cases. In conclusion, the combination of a full-thickness cartilage lesion and an ACL rupture did not result in inferior knee function at the time of the ACL reconstruction as measured by the KOOS.     

Self-efficacy, symptoms and physical activity in patients with an anterior cruciate ligament injury: a prospective study

Self-efficacy belief may be of major importance for the outcome of rehabilitation after sports-related injuries. A new instrument, the Knee Self-Efficacy Scale (K-SES), was used to evaluate the role of perceived self-efficacy in patients with an anterior cruciate ligament (ACL) injury. The purpose of this prospective exploratory study was to describe the patients' perceived self-efficacy at various times post-injury and surgery, respectively, for responsiveness of the K-SES and to correlate the K-SES score with the patients' subjective symptoms. The purpose was also to describe the influence of gender, age and physical activity on the patients' perceived self-efficacy. Thirty recently injured patients with an ACL-deficient knee and 33 patients who had undergone ACL reconstruction reported their physical activity level and their perceived self-efficacy on four test occasions during a 1-year period. The patients' subjective knee symptoms were documented on two of the test occasions. A significant increase in the K-SES score was seen after injury as well as after surgery, during the course of rehabilitation. Pre-operatively, men's perceived self-efficacy was significantly (P=0.013) higher compared with women's self-efficacy. Patients with a high baseline (pre-injury) physical activity level (Tegner 7-10) perceived their self-efficacy as being significantly (P=0.005) higher pre-operatively compared with patients with a low baseline activity level (Tegner 3-6). "Younger" (age 17-29), recently injured patients, perceived their self-efficacy as being significantly (P=0.034) higher compared with "older" patients (age 30-54). At the 12-month test, 15 of 30 patients with an ACL-deficient knee and 15 of 33 patients who had undergone ACL reconstruction reported that they had returned or nearly returned to their baseline physical activity level. The subjective knee outcome score, as measured by the Knee Injury and Osteoarthritis Outcome Score (KOOS), improved significantly (P<0.01) during rehabilitation, apart from the KOOS subscale of "pain" (P=0.077) for patients who had undergone ACL reconstruction. There was a "low" to "strong" correlation (r(s)=0.0-0.7) between the K-SES and the five subscales in the KOOS. We conclude from the present study that K-SES has good responsiveness with significantly increased self-efficacy during the rehabilitation process for patients with an ACL-deficient knee as well as for patients who had undergone ACL reconstruction. The improvement in perceived self-efficacy could, however, only be partly explained by the improvement in subjective symptoms. Furthermore, self-efficacy differed significantly with gender, age and physical activity level early in the rehabilitation process.     

Factors affecting outcome after anterior cruciate ligament injury: a prospective study with a six-year follow-up

The aim of this study was to investigate whether gender, age, stable personality traits, associated meniscus and/or articular cartilage injuries, treatment (non-operative or reconstructive surgery), additional subsequent trauma to the anterior cruciate ligament (ACL)-injured knee and activity level before injury affect the intermediate outcome after ACL injury. The primary outcome was the Knee injury and Osteoarthritis Outcome Score (KOOS). Fifty-seven patients, 18-50 years old with an acute, unilateral ACL tear were included in the study. At the time of inclusion, the patients completed the Tegner score, regarding activity level before injury, and Swedish universities Scales of Personality (SSP). At follow-up, after 5.6 years they completed the KOOS, the Tegner score and a general questionnaire concerning ACL reconstruction and subsequent knee trauma. The subjects who had sustained additional trauma subsequent to their ACL injury had a significantly worse outcome according to the KOOS than those who had not. Furthermore, low ratings in the embitterment scale in the SSP were correlated to a better outcome in the KOOS. Treatment did not affect the KOOS total score. However, the non-operatively treated subjects had a significantly better outcome according to the knee-related quality-of-life domain in the KOOS.     

A new instrument for measuring self-efficacy in patients with an anterior cruciate ligament injury

It has been suggested that self-efficacy belief is of major importance for rehabilitation outcome after sports-related injuries. No instruments are, however, available to evaluate perceived self-efficacy for prognostic and outcome expectations in patients with an anterior cruciate ligament (ACL) injury. Perceived self-efficacy is defined as a judgment of one's potential ability to carry out a task, rather than a measure of whether or not one actually can or does perform the task. The purpose of this study was to develop a reliable and valid instrument for measuring perceived self-efficacy in patients with an ACL injury. A total of 210 male and female patients with an ACL injury were included in this study. The items were generated by health professionals with long clinical experience of patients with an ACL injury and by discussions with patients. After item analysis and item reduction, based on the results from 88 patients, the final 22-item version of the Knee Self-Efficacy Scale (K-SES) was evaluated in 18 patients for test-retest reliability and in 104 patients for internal consistency and validity. The K-SES was compared with the Multidimensional Health Locus of Control (MHLC), Coping Strategies Questionnaire (CSQ), SF-36 and Knee Injury and Osteoarthritis Outcome Score (KOOS) instruments. A factor analysis was also performed on the K-SES. The test-retest revealed a correlation of r(s)=0.73 between test-days and an intraclass correlation coefficient of 0.75. No significant difference between test-days was found. The internal consistency was 0.94, as calculated with Cronbach's alpha. There were low correlations between the K-SES and MHLC and the K-SES and CSQ, respectively. A strong correlation was found between the K-SES and physical functioning, as measured by the SF-36 (r(s)=0.8). All the sub-scales in the KOOS correlated moderately to strongly (r(s)=0.4-0.7) to the K-SES. The factor analysis produced two factors of importance. Factor one was related to how patients perceived their present physical performance/function, while factor two was related to how patients perceived the future physical performance/prognosis of their knee. Good reliability and good face, content, construct and convergent validity were demonstrated for this new instrument (K-SES) for measuring perceived self-efficacy in patients with an ACL injury. The K-SES is recommended for studies designed to evaluate prognostic and outcome expectations of perceived self-efficacy in patients with an ACL-insufficient knee.     

Outcomes after ACL reconstruction with focus on older patients: results from The Swedish National Anterior Cruciate Ligament Register

Purpose

To investigate and analyse outcomes of patients over the age of 40 who had undergone anterior cruciate ligament (ACL) reconstruction and to compare them to their younger counterparts. We analysed patient-reported outcomes measured using the knee injury and osteoarthritis outcome score (KOOS) as well as aetiology of injury, concomitant intra-articular injuries and time from injury to surgery.

Methods

Data were extracted from the Swedish National Knee Ligament Register during the period of 2005 through 2012. The following data were extracted and analysed: patient age, gender, activity at the time of injury, time between injury and reconstruction, concomitant intra-articular injuries, graft size used for reconstruction and KOOS measured pre-operatively as well as 1, 2 and 5 years post-operatively. The cohort was stratified into age groups of 0–19, 20–29, 30–39 and ≥40 years of age.

Results

Pivoting sports were dominating as the cause of ACL injury in the younger age groups (up to 39 years). Alpine skiing and other non-specified activities were the most common causes in the older age group (≥40 years). Pre-operative KOOS was significantly lower in older age groups (p < 0.01). Post-operative KOOS regarding all subscales was significantly better in the older age group. The improvement in KOOS was significant with increasing age (p < 0.01). Older patients exhibited the greatest improvement in KOOS for all subscales at 1, 2 and 5 years post-operative follow-ups compared with pre-operative values (p < 0.01). Older patients had more cartilage injuries pre-operatively compared with younger patients. The same trend was observed in the older group for meniscus injury with and without cartilage injuries. The diameter of the graft used for ACL reconstruction was significantly larger in the older age groups and largest in the age group ≥40 years (p < 0.01). Older patients waited significantly longer for surgery after the ACL injury (p < 0.01).

Conclusion

In the older age groups, patients reported lower pre-operative KOOS compared with their younger counterparts. At follow-up, KOOS was similar in all age groups. From these results, we can therefore conclude that our hypothesis confirmed that optimal surgical results can in fact be achieved even in older patients.

Level of evidence

II.     

Outcome and knee-related quality of life after anterior cruciate ligament reconstruction: a long-term follow-up

The aim of the present investigation was to study patient-reported long-term outcome after anterior cruciate ligament (ACL) reconstruction. On an average 11.5 years after ACL reconstruction with bone-patellar tendon-bone (BPTB) autograft 56 patients were asked to answer four different questionnaires about their knee function and knee-related quality of life. Another aim was to study whether there were any correlations between clinical tests, commonly used for evaluating patients with ACL injuries, which were performed 2 years after ACL reconstruction, and patient-reported outcome in terms of knee function and knee-related quality of life on an average 9.5 years later. All patients who had unilateral BPTB ACL reconstructions were examined at 2 years and on an average 11.5 years after surgery. At 2 years one-leg hop test for distance, isokinetic muscle torque measurement, sagittal knee laxity, Lysholm knee scoring scale and Tegner activity scale were used for clinical evaluation. At the follow-up on an average 9.5 years later the patients were evaluated with knee injury osteoarthritis outcome score (KOOS), short form health survey (SF 36), Lysholm knee scoring scale and Tegner activity scale. The SF-36 showed that the patients had a similar health condition as an age- and gender-matched normal population in Sweden on an average 11.5 years after ACL reconstruction. There was no correlation between the results of one-leg hop test for distance, isokinetic muscle torque measurement, sagittal knee laxity evaluated 2 years after surgery and the result of KOOS (function in sport and recreation, knee-related quality of life) and SF-36 evaluated on an average 11.5 years after surgery. We also compared patients that 2 years after surgery demonstrated a side-to-side difference in anterior–posterior knee laxity of more than 3 mm with those with 3 mm or less and found no significant group differences in terms of knee function as determined with KOOS. We found no correlation between the results of KOOS and SF-36 at the long-term follow-up and the time between injury and surgery, age at surgery or gender, respectively. We conclude that there is no correlation between patient-reported knee function in sport and recreation and knee-related quality of life on an average 11.5 years after BPTP ACL reconstruction and the evaluation methods used 2 years after surgery.     

Rigorous statistical reliability, validity, and responsiveness testing of the Cincinnati knee rating system in 350 subjects with uninjured, injured, or anterior cruciate ligament-reconstructed knees.

Although many instruments are used to assess outcome after knee ligament reconstruction, their reliability, validity, and responsiveness have not been adequately proven. Our purpose was to assess these statistical measures in a commonly used instrument, the Cincinnati Knee Rating System. Reliability was determined from the responses of 100 subjects who completed the instrument twice, a mean of 7 days apart. Validity and responsiveness were assessed from 250 patients observed for at least 2 years after autogenous ACL reconstruction. Questionnaire items included symptoms, functional limitations with sports and daily activities, patient perception of the knee condition, and sports- and occupational-activity levels. The items demonstrated high test-retest reliability, supporting their use in evaluating groups of patients between two different treatment periods (all intraclass correlation coefficients > 0.70). In addition, the questionnaire demonstrated good content validity, construct validity, and item-discriminant validity. For the overall rating score, no "floor effects" (worst score possible) were found before or after surgery. No "ceiling effects" (best score possible) were found before surgery, and, at follow-up, these effects were calculated in only 22 patients (9%). The questions were found to be highly responsive to detecting changes between evaluations. The data demonstrated that this rating system has acceptable reliability, validity, and responsiveness for use in outcome studies after knee ligament reconstruction.     

Translation and validation of the simplified Chinese version of the anterior cruciate ligament-return to sport after injury (ACL-RSI)

Purpose

The aim of this study is to obtain a translation and adaptation of the anterior cruciate ligament-return to sport after injury (ACL-RSI) into simplified Chinese and validate the simplified Chinese version.

Methods

Translation and adaptation were performed according to the guidelines of the American Academy of Orthopaedic Surgeons Outcome Committee. A total of 122 patients who were diagnosed with an ACL injury and underwent primary arthroscopic anterior cruciate ligament reconstruction (ACLR) between 2015 and 2016 were included in this study. The simplified Chinese version of the ACL-RSI (SC-ACL-RSI), Knee injury and Osteoarthritis Outcome Score (KOOS), Lysholm score and International Knee Documentation Committee (IKDC) subjective knee form were completed. Psychometric evaluations included score distribution, internal consistency, test–retest reliability, and construct and discriminant validity.

Results

SC-ACL-RSI scores exhibited a normal distribution without ceiling and floor effects. Internal consistency was high (Cronbach’s alpha?=?0.94). The intraclass correlation coefficient was 0.98, indicating excellent test–retest reliability. SC-ACL-RSI scores were correlated with all KOOS subscales (r?=?0.30 to 0.69, p?<?0.001), the IKDC subjective knee form (r?=?0.46, p?<?0.001) and the Lysholm score (r?=?0.56, p?<?0.001). The mean scores between patients who returned to the same preinjury level of sport (65.1?±?14.3) and those who could not return to the same level (51.0?±?15.0) were significantly different (p?<?0.001).

Conclusions

The SC-ACL-RSI is a reliable and valid instrument to evaluate the psychological impact of a patient returning to sport after ACLR. It is important to evaluate patients’ ability to return to sport after an ACL injury. The information provided by the SC-ACL-RSI will affect decisions regarding treatment and rehabilitation plans, which are more likely to influence clinical outcomes.

Level of evidence

II.

     

Knee function among elite handball and football players 1‐6 years after anterior cruciate ligament injury

The aim of the study was to describe objective and self‐reported knee function for athletes who have returned to elite handball and football play after an ACL injury, comparing these to non‐injured players at the same level. A total of 414 handball and 444 football players completed baseline tests from 2007 through 2014, examining lower extremity strength, dynamic balance, knee laxity, and knee function (KOOS questionnaire). Measures were compared between injured and non‐injured legs and between injured legs and legs of controls. Eighty (9.3%) of the 858 players reported a previous ACL injury, 1‐6 years post‐injury (3.5±2.5 years), 49 handball (61.3%) and 31 football players (38.7%). We found no difference in strength or dynamic balance between previously ACL‐injured (N=80) and non‐injured players legs (N=1556). However, lower quadriceps (6.3%, 95% CI: 3.2‐9.2) and hamstrings muscle strength (6.1%, 95% CI: 3.3‐8.1) were observed in previously ACL‐injured legs compared to the non‐injured contralateral side (N=80). ACL‐injured knees displayed greater joint laxity than the contralateral knee (N=80, 17%, 95% CI: 8‐26) and healthy knees (N=1556, 23%, 95% CI: 14‐33). KOOS scores were significantly lower for injured knees compared to knees of non‐injured players. ACL‐injured players who have successfully returned to elite sport have comparable strength and balance measures as their non‐injured teammates. Subjective perception of knee function is strongly affected by injury history, with clinically relevant lower scores for the KOOS subscores Pain, Function, Sport, and Quality Of Life.     

Activity level and subjective knee function 15 years after anterior cruciate ligament injury: a prospective, longitudinal study of nonreconstructed patients

BACKGROUND: The activity level and subjective knee function after an anterior cruciate ligament (ACL) injury treated without reconstruction have not been well elucidated. HYPOTHESIS: Patients with ACL injury can achieve good knee function and satisfactory long-term activity level when treated by early activity modification combined with rehabilitation. STUDY DESIGN: Cohort study (prognosis); Level of evidence, 2. Materials and METHODS: One hundred patients with an acute total ACL injury were observed for 15 years. All patients initially underwent arthroscopic surgery and a rehabilitation program. They were advised to modify their activity level, especially by avoiding contact sports. Patients with recurrent giving-way episodes and/or secondary meniscal injuries that required fixation (n = 6) were subsequently excluded and underwent reconstruction (n = 22). Sixty-seven patients with unilateral nonreconstructed ACL injury remained at the 15-year follow-up. The Lysholm knee score, Tegner activity level, and a visual analog score for global knee function were recorded at regular intervals. At the final follow-up, patients were further evaluated with the Knee injury and Osteoarthritis Outcome Score (KOOS) and International Knee Documentation Committee (IKDC) subjective knee evaluation form. RESULTS: Forty patients resumed their preinjury activity level or higher within 3 years. The median activity level 15 years after injury had decreased from 7 to 4 according to Tegner activity scale (P < .001). The mean Lysholm knee score was 96 and 95, 1 and 3 years after injury, respectively, but declined to 86 after 15 years (P < .001). Forty-nine patients had good/excellent results, and 14 had fair (n = 6) or poor function (n = 8) at 15 years. Patients injured in contact sports scored lower in the quality of life sub-scale of KOOS than those injured in noncontact sports (P < .05). Thirteen of the 67 patients (19%) were reoperated with an arthroscopic procedure because of knee symptoms. CONCLUSION: Early activity modification and neuromuscular rehabilitation resulted in a good knee function and an acceptable activity level in the majority of the nonreconstructed patients. The decline in activity level of patients engaged in contact sports at the time of injury affected their subjective quality of life more than patients involved in noncontact sports.     

An isolated rupture of the posterior cruciate ligament results in reduced preoperative knee function in comparison with an anterior cruciate ligament injury

Purpose

To investigate differences in preoperative knee function (Knee Injury and Osteoarthritis Outcome Score, KOOS), the time period from injury to surgery, and associated injuries when comparing primary isolated posterior cruciate ligament (PCL) and primary anterior cruciate ligament (ACL) reconstructions.

Methods

Isolated primary ACL and PCL reconstructions registered in the Norwegian National Knee Ligament Registry from 2004 through 2010 were included (n = 71 primary PCLs and 9,649 primary ACLs). Linear regression analysis was used to evaluate the preoperative KOOS subscale values.

Results

The preoperative KOOS in the PCL group (n = 71) and ACL group (n = 9,649) was significantly different for the subscales symptoms (mean difference, ?8.4; 95 % CI: ?12.8 to ?4.0), pain (mean difference, ?15.9; 95 % CI: ?20.3 to ?11.4), activities of daily living (mean difference, ?12.9; 95 % CI: ?17.4 to ?8.4), sport and recreation (mean difference, ?15.9; 95 % CI: ?22.6 to ?9.3), and quality of life (mean difference, ?7.9; 95 % CI: ?12.4 to ?3.5). The primary isolated PCL-reconstructed knees had a median time from injury to surgery of 21 months in comparison with 8 months for ACL injuries. The ACL-injured knees had more associated injuries (meniscus and full-thickness cartilage lesions) than the PCL-injured knees.

Conclusion

Surgically treated knees with an isolated rupture of the PCL exhibited worse knee function preoperatively compared with knees with an isolated ACL injury; in addition, the delay to surgery was longer. Meniscal lesions were found more frequently in ACL-injured knees.

Level of evidence

Prospective cohort study, evidence Level I.     

Translation and measurement properties of the Swedish version of ACL‐Return to Sports after Injury questionnaire

Psychological factors may be a hindrance for returning to sport after an anterior cruciate ligament (ACL) reconstruction. The ACL‐Return to Sport after Injury scale (ACL‐RSI) measures athletes' emotions, confidence in performance, and risk appraisal in relation to return to sport. The aim of this study was to translate the ACL‐RSI scale from English to Swedish and to examine some of the measurement properties of the Swedish version. The ACL‐RSI was translated and culturally adapted. A professional expert group and five patients evaluated face validity. One hundred and eighty‐two patients completed the translated ACL‐RSI, a project‐specific questionnaire, the Tampa Scale of Kinesiophobia (TSK), the Knee‐Self‐Efficacy Scale (K‐SES), the Multidimensional Health Locus of Control (MHLC‐C), the Knee injury and Osteoarthritis Outcome Score (KOOS), and the Anterior Cruciate Ligament‐Quality of Life (ACL‐QoL) questionnaires. Fifty‐three patients answered the ACL‐RSI twice to examine reproducibility. The ACL‐RSI showed good face validity, internal consistency (Cronbach's alpha = 0.948), low floor and ceiling effects and high construct validity when evaluated against the TSK, K‐SES, MHLC‐C, KOOS, and ACL‐QoL scales. The reproducibility was also high (intra‐class correlation = 0.893). Therefore, the ACL‐RSI can be used to evaluate psychological factors relevant to returning to sport after ACL reconstruction surgery.     

Who chooses anterior cruciate ligament reconstruction and why? A 2‐year prospective study

The purpose of this study was to investigate possible differences in age, gender, Tegner activity level prior to injury, knee joint laxity and the variables evaluated with knee osteoarthritis outcome score (KOOS) between patients who chose non-operative treatment (NT), early reconstruction (ER) and late reconstruction (LR). A second aim was to study whether patients who choose ER choose surgical treatment for the same reasons as patients who choose LR. Seventy-two patients with an acute (< 1 month) anterior cruciate ligament (ACL) tear, who had not yet decided to have surgery, were included in this study. They filled out the Tegner activity score, assessing preinjury activity level, KOOS and underwent KT-1000 arthrometer examination. The 36 subjects who later chose reconstruction were questioned about reasons for their decision. A high preinjury activity level was associated with the choice of ACL reconstruction, but the choice of treatment was not associated with age, gender or the outcome variables measured with KOOS or KT-1000. Fifteen out of the 20 (75%) subjects who chose ER based their decision on assumptions of future problems and not on experience of knee function. Fourteen out of 16 (88%) subjects, who chose reconstructive surgery later, based their decision on experience of knee function.     

Does a history of youth sport-related knee injury still impact accelerometer-measured levels of physical activity after 3–12 years?

ObjectivesTo examine accelerometer-measured physical activity (PA) in individuals with a knee injury history and controls and the association of moderate to vigorous PA (MVPA) with self-reported and performance measures of knee function.DesignHistorical cohort.ParticipantsParticipants with a 3–12 year history of youth sport-related knee injury and matched controls.Main outcome measuresMVPA (Actigraph GT3x-BT), Knee Injury and Osteoarthritis Outcome Score (KOOS), Triple Single-Leg Hop, Y-Balance and isometric knee strength was measured. Regression analyses examined differences in PA and the association between MVPA and knee function, adjusted for injury history, sex and time since injury.ResultsParticipants (42 injured, 43 controls) had a median age of 23.4 (range 16–29) years. The previously injured group spent less daily adjusted minutes in MVPA [-13.5 (95% CI -25.6, −1.4)] than controls, and females had 10.8 min (95% CI -20.2, −1.4) less MVPA than males. Higher MVPA was associated with better KOOS sport and recreation [β = 0.05, 95% CI (0.01, 0.09)] adjusted for injury history. No other associations were observed.ConclusionPreviously injured youth participated in less MVPA compared to controls 3–12 years later. Lower MVPA is associated with poorer self-reported sport and recreation knee function which may have long-term negative health consequences.