Influence of Surgeon Experience and Clinic Volume on Subjective Knee Function and Revision Rates in Primary ACL Reconstruction: A Study from the Swedish National Knee Ligament Registry.

Background: Anterior cruciate ligament reconstruction (ACLR) performed by high-volume surgeons/clinics has been associated with increased graft individualization and decreased operating times, complication rates, and total costs. Purpose: To investigate the influence of surgeon/clinic volume on subjective knee function and revision surgery rates at 2 years after primary ACLR. Study Design: Cohort study; Level of evidence, 3. Methods: Data from the Swedish National Knee Ligament Registry were used to study patients who underwent primary ACLR between 2008 and 2019. Surgeons/clinics were categorized based on a combination of total caseload volume (cutoff: 50 ACLRs/surgeon, 500 ACLRs/clinic) and annual volume (cutoff: 29 ACLRs/year/surgeon, 56 ACLRs/year/clinic). The thresholds of minimal important change (MIC), Patient Acceptable Symptom State (PASS), and treatment failure (TF) relative to the Knee injury and Osteoarthritis Outcome Score (KOOS) and KOOS4 (mean score of the KOOS Pain, Symptoms, Sports/Rec, and QoL subscales) were applied. Adjusted multivariable logistic regression was performed to assess variables influencing the MIC, PASS, or TF of the KOOS and KOOS4. Adjusted Cox regression analysis was conducted to determine the hazard ratio of subsequent ACLR. Results: Of 35,371 patients, 16,317 had 2-year follow-up outcome data and were included. Patients who underwent primary ACLR by high-volume surgeons had significantly higher MIC and PASS rates and lower TF rates when compared with patients who underwent the procedure by low-volume surgeons: MICKOOS4: 70.6% vs 66.3%; PASSKOOS4: 46.0% versus 38.3%; and TFKOOS4: 8.7% versus 11.8% (all P < .02). Significantly decreased odds of achieving MICKOOS4 (OR, 0.74; 95% CI, 0.62-0.88) and PASSKOOS4 (OR, 0.71; 95% CI, 0.60-0.84) were found for ACLRs performed by low-volume surgeons. Clinic volume did not influence the odds of reaching MIC, PASS, or TF. Overall, 804 patients (2.3%) underwent subsequent ACLR at <2 years, with significantly higher revision rates among patients operated on at high-volume clinics (2.5% vs 1.7%; P < .001). However, in the adjusted Cox regression, surgeon/clinic volume had no influence on subsequent ACLR rates. High-volume surgeons/clinics had decreased time to surgery, operating time, perioperative complication rates, and use of thromboprophylaxis and nonroutine antibiotics (P < .001). Conclusion: Patients who underwent primary ACLR by high-volume surgeons experienced increased improvement and satisfaction regarding subjective knee function. Factors other than surgical volume influenced subsequent surgery rates. Patients might benefit from undergoing primary ACLR by high-volume providers.

Depression and anxiety-related disorders and suicide among Swedish male elite football players: a nationwide cohort study.

OBJECTIVE: To assess whether male elite football players, during and after their active career, were at increased risk of depression and anxiety-related disorders and suicide, as compared with the general male population. METHODS: We included male football players active in the Swedish top division 1924-2019 and general male population (matched to football players based on age and region of residence) aged <65 years in 1997. Using nationwide registers, we followed the football players from their first season in the top division (or the date of their first registered residency in Sweden) or 1 January 1997, and compared the risk of depression and anxiety-related disorders (captured through diagnoses from hospital admissions and outpatient visits, and use of prescription drugs) among football players versus controls. In a secondary analysis using data from death certificates, we compared the risk of suicide between football players and general population males who were alive in 1969 (when cause of death became available) . RESULTS: During follow-up through 31 December 2020, 504 (13.6%) of 3719 football players and 7455 (22.3%) of 33 425 general population males had a depression or anxiety-related disorder. In analyses accounting for age, region of residence and calendar time, the risk of anxiety and depression-related disorders was lower among football players versus general population males (HR 0.61, 95% CI 0.55 to 0.66). The protective association was attenuated with increasing age, and from around age 70 years the risk was similar in the two groups. The risk of suicide was lower among football players versus general population males (HR 0.48, 95% CI 0.32 to 0.72). CONCLUSIONS: In this nationwide cohort study in Sweden, elite male football players had a lower risk of depression and anxiety-related disorders and suicide as compared with the general population.

The Addition of the Gracilis Tendon to a Semitendinosus Tendon Autograft Is Not Associated With Knee Muscle Strength, Subjective Knee Function, or Revision Surgery After Anterior Cruciate Ligament Reconstruction.

PURPOSE: To evaluate and compare isokinetic knee muscle (extension and flexion) strength, single-leg hop (SLH) test performance, anterior knee laxity, subjective knee function, and the 2-year revision surgery risk between patients who underwent anterior cruciate ligament reconstruction (ACLR) with semitendinosus tendon (ST) autografts and patients who underwent ACLR with ST and gracilis tendon (ST-G) autografts. METHODS: We identified patients aged 16 years or older who underwent primary ACLR with hamstring tendon autografts at our institution from January 2005 to December 2020 and had no associated ligament injuries. Isokinetic knee muscle strength and SLH test performance were assessed 6 months postoperatively. Anterior knee laxity (KT-1000 arthrometer, 134 N) was assessed preoperatively and 6 months postoperatively. The Knee Injury and Osteoarthritis Outcome Score (KOOS) was collected preoperatively and 1 and 2 years postoperatively. Patients who underwent revision ACLR at any institution in Sweden within 2 years of primary surgery were identified through the Swedish National Knee Ligament Registry. RESULTS: A total of 6,974 patients (5,479 with ST and 1,495 with ST-G) were included. There were no significant differences in extension and flexion strength or SLH test performance between the groups. Preoperatively, there was no significant difference in knee laxity between the ST and ST-G groups. Postoperatively, the ST-G group had significantly increased mean side-to-side (STS) laxity (2.1 ± 2.3 mm vs 1.7 ± 2.2 mm, P < .001) and showed a trend toward increased STS laxity according to the International Knee Documentation Committee form, with significantly fewer patients with STS laxity of 2 mm or less (58.4% vs 65.8%) and significantly more patients with STS laxity between 3 and 5 mm (35.0% vs 29.9%) or greater than 5 mm (6.6% vs 4.3%) (P < .001). The only significant difference in subjective knee function was for the KOOS Quality of Life subscale score in favor of the ST group preoperatively (37.3 ± 21.4 vs 35.1 ± 19.9, P = .001). No other significant differences between the groups were found preoperatively and 1 and 2 years postoperatively for any of the KOOS subscales. The overall revision ACLR rate within 2 years of primary surgery was 2.0% (138 of 6,974 patients). The revision ACLR risk in the ST-G group (1.7%, 25 of 1,495 patients) was not significantly different from that in the ST group (2.1%, 113 of 5,479 patients) (hazard ratio, 0.80; 95% confidence interval, 0.50-1.24; P = .32). CONCLUSIONS: The addition of the gracilis tendon to an ST autograft was not associated with knee muscle strength, SLH test performance, subjective knee function, or the risk of revision surgery after ACLR. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Neurodegenerative disease among male elite football (soccer) players in Sweden: a cohort study.

BACKGROUND: Football (soccer) players might be at increased risk of neurodegenerative disease, which has led to questions regarding the safety of the sport and recent measures introduced by football associations to reduce heading of the ball. We aimed to assess the risk of neurodegenerative disease among male football players in the Swedish top division Allsvenskan, compared with matched controls. METHODS: In this cohort study, we identified all male football players (amateurs and professionals) who had played at least one game in Allsvenskan from Aug 1, 1924 to Dec 31, 2019 and excluded players whose personal identity number could not be retrieved or be identified in the Total Population Register, and those who were not born in Sweden and who had immigrated to the country after age 15 years. Football players were matched with up to ten controls from the general population according to sex, age, and region of residence. We used nationwide registers to compare the risk of neurodegenerative disease (diagnoses recorded in death certificates, during hospital admissions and outpatient visits, or use of prescription drugs for dementia) among football players versus controls. We also assessed each type of neurodegenerative disease (Alzheimer's disease and other dementias, motor neuron disease, and Parkinson's disease) separately, and compared the risk of neurodegenerative disease among outfield players versus goalkeepers. FINDINGS: Of 7386 football players who had played at least one game in the top Swedish division between Aug 1, 1924, and Dec 31, 2019, 182 players were excluded for an unretrievable personal identity number, and 417 were excluded due to their number not being identified in the Total Population Register. After a further exclusion of 780 players and 11 627 controls who were born outside of Sweden and who had immigrated to the country after age 15 years, 6007 football players (510 goalkeepers) were included in the study population along with 56 168 matched controls. During follow-up to Dec 31, 2020, 537 (8·9%) of 6007 football players and 3485 (6·2%) of 56 168 controls were diagnosed with neurodegenerative disease. The risk of neurodegenerative disease was higher among football players than controls (hazard ratio [HR] 1·46 [95% CI 1·33-1·60]). Alzheimer's disease and other dementias were more common among football players than controls (HR 1·62 [95% CI 1·47-1·78]), significant group differences were not observed for motor neuron disease (HR 1·27 [0·73-2·22]), and Parkinson's disease was less common among football players (HR 0·68 [0·52-0·89]). The risk of neurodegenerative disease was higher for outfield players than controls (HR 1·50 [95% CI 1·36-1·65]) but not for goalkeepers versus controls (HR 1·07 [0·78-1·47]), and outfield players had a higher risk of neurodegenerative disease than did goalkeepers (HR 1·43 [1·03-1·99]). All-cause mortality was slightly lower among football players than controls (HR 0·95 [95% CI 0·91-0·99]). INTERPRETATION: In this cohort study, male football players who had played in the Swedish top division had a significantly increased risk of neurodegenerative disease compared with population controls. The risk increase was observed for Alzheimer's disease and other dementias but not for other types of neurodegenerative disease, and among outfield players, but not among goalkeepers. Our study expands on the data that can be used to assess and manage risks in the sport. FUNDING: Karolinska Institutet, The Swedish Research Council for Sport Science, Folksam Research Foundation, Hedberg Foundation, Neurofonden, and Åhlen Foundation.

Surgeon's experience, sports participation and a concomitant MCL injury increase the use of patellar and quadriceps tendon grafts in primary ACL reconstruction: a nationwide registry study of 39,964 surgeries.

PURPOSE: To investigate the influence of surgeon-related factors and clinic routines on autograft choice in primary anterior cruciate ligament reconstruction (ACLR). METHODS: Data from the Swedish National Knee Ligament Registry (SNKLR), 2008-2019, were used to study autograft choice (hamstring; HT, patellar; PT, or quadriceps tendon; QT) in primary ACLR. Patient/injury characteristics (sex, age at surgery, activity at time of injury and associated injuries) and surgeon-/clinic-related factors (operating volume, caseload and graft type use) were analyzed. Surgeon/clinic volume was divided into tertiles (low-, mid- and high-volume categories). Multivariable logistic regression was performed to assess variables influencing autograft choice in 2015-2019, presented as the odds ratio (OR) with a 95% confidence interval (CI). RESULTS: 39,964 primary ACLRs performed by 299 knee surgeons in 91 clinics were included. Most patients received HT (93.7%), followed by PT (4.2%) and QT (2.1%) grafts. Patients were mostly operated on by high-volume (> 28 ACLRs/year) surgeons (68.1%), surgeons with a caseload of ≥ 50 ACLRs (85.1%) and surgeons with the ability to use ≥ two autograft types (85.9%) (all p < 0.001). Most patients underwent ACLR at high-volume (> 55 ACLRs/year) clinics (72.2%) and at clinics capable of using ≥ two autograft types (93.1%) (both p < 0.001). Significantly increased odds of receiving PT/QT autografts were found for ACLR by surgeons with a caseload of ≥ 50 ACLRs (OR 1.41, 95% CI 1.11-1.79), but also for injury during handball (OR 1.31, 95% CI 1.02-1.67), various other pivoting sports (basketball, hockey, rugby and American football) (OR 1.59, 95% CI 1.24-2.03) and a concomitant medial collateral ligament (MCL) injury (OR 4.93, 95% CI 4.18-5.80). In contrast, female sex (OR 0.87, 95% CI 0.77-0.97), injury during floorball (OR 0.71, 95% CI 0.55-0.91) and ACLR by mid-volume relative to high-volume surgeons (OR 0.62, 95% CI 0.53-0.73) had significantly reduced odds of receiving PT/QT autografts. CONCLUSION: An HT autograft was used in the vast majority of cases, but PT/QT autografts were used more frequently by experienced surgeons. Prior research has demonstrated significant differences in autograft characteristics. For this reason, patients might benefit if surgery is performed by more experienced surgeons. LEVEL OF EVIDENCE: Level III.

Alcohol related disorders among elite male football players in Sweden: nationwide cohort study.

OBJECTIVES: To assess whether male elite football players are at increased risk of alcohol related disorders compared with men from the general population, and whether such an increased risk would vary on the basis of calendar year of the first playing season in the top tier of competition, age, career length, and goal scoring abilities. DESIGN: Nationwide cohort study. SETTING: Sweden, 1924-2020. PARTICIPANTS: 6007 male football players who had played in the Swedish top division, Allsvenskan, from 1924 to 2019 and 56 168 men from the general population matched to players based on age and region of residence. MAIN OUTCOME MEASURES: Primary outcome was alcohol related disorders (diagnoses recorded in death certificates, during hospital admissions and outpatient visits, or use of prescription drugs for alcohol addiction); secondary outcome was disorders related to misuse of other drugs. RESULTS: During follow-up up to 31 December 2020, 257 (4.3%) football players and 3528 (6.3%) men from the general population received diagnoses of alcohol related disorders. In analyses accounting for age, region of residence, and calendar time, risk of alcohol related disorders was lower among football players than among men from the general population (hazard ratio 0.71, 95% confidence interval 0.62 to 0.81). A reduced risk of alcohol related disorders was observed for football players who played their first season in the top tier in the early 1960s and later, while no significant difference versus men from the general population was seen in the risk for football players from earlier eras. The hazard ratio was lowest at around age 35 years, and then increased with age; at around age 75 years, football players had a higher risk of alcohol related disorders than men from the general population. No significant association was seen between goal scoring, number of games, and seasons played in the top tier and the risk of alcohol related disorders. Risk of disorders related to other drug misuse was significantly lower among football players than the general population (hazard ratio 0.22, 95% confidence interval 0.15 to 0.34). CONCLUSIONS: In this nationwide cohort study, male football players who had played in the Swedish top tier of competition had a significantly lower risk of alcohol related disorders than men from the general population.

Age, time from injury to surgery and hop performance after primary ACLR affect the risk of contralateral ACLR.

PURPOSE: To evaluate factors affecting the risk of contralateral anterior cruciate ligament reconstruction (ACLR) within 5 years of primary ACLR. METHODS: Primary ACLRs performed at Capio Artro Clinic, Stockholm, Sweden, during the period 2005-2014, were reviewed. The outcome of the study was the occurrence of contralateral ACLR within 5 years of primary ACLR. Univariable and multivariable logistic regression analyses were employed to identify preoperative [age, gender, body mass index (BMI), time from injury to surgery, pre-injury Tegner activity level], intraoperative [graft type, medial meniscus (MM) and lateral meniscus (LM) resection or repair, cartilage injury] and postoperative [limb symmetry index (LSI) for quadriceps and hamstring strength and single-leg-hop test performance at 6 months] risk factors for contralateral ACLR. RESULTS: A total of 5393 patients who underwent primary ACLR were included. The incidence of contralateral ACLR within 5 years was 4.7%. Univariable analysis revealed that age ≥ 25 years, BMI ≥ 25 kg/m2, time from injury to surgery ≥ 12 months and the presence of a cartilage injury reduced the odds, whereas female gender, pre-injury Tegner activity level ≥ 6, quadriceps and hamstring strength and a single-leg-hop test LSI of ≥ 90% increased the odds of contralateral ACLR. Multivariable analysis showed that the risk of contralateral ACLR was significantly affected only from age ≥ 25 years (OR 0.40; 95% CI 0.28-0.58; P < 0.001), time from injury to surgery ≥ 12 months (OR 0.48; 95% CI 0.30-0.75; P = 0.001) and a single-leg-hop test LSI of ≥ 90% (OR 1.56; 95% CI 1.04-2.34; P = 0.03). CONCLUSION: Older age (≥ 25 years) and delayed primary ACLR (≥ 12 months) reduced the odds, whereas a symmetrical (LSI ≥ 90%) 6-month single-leg-hop test increased the odds of contralateral ACLR within 5 years of primary ACLR. Knowledge of the factors affecting the risk of contralateral ACLR is important when it comes to the appropriate counselling for primary ACLR. Patients should be advised regarding factors affecting the risk of contralateral ACLR. LEVEL OF EVIDENCE: Level III.

Increased occurrence of ACL injuries for football players in teams changing coach and for players going to a higher division.

PURPOSE: To identify football-specific factors associated with ACL injuries that can be targeted for sport-specific injury prevention. METHODS: A study-specific questionnaire was developed to study the characteristics of ACL injuries in football including intrinsic, extrinsic, and injury specific factors. The questionnaire was available at the Swedish national knee ligament registry's website for the football players to voluntarily fill out. Data are presented on group level for all football players in total and for females and males separate to examine gender-specific differences. The results are based on answers collected over a 3-year period from 2875 football players, 1762 (61%) males and 1113 (39%) females. RESULTS: ACL were more frequently sustained during games 66% than during practices 25%. The injury mechanism was non-contact in 59% and contact in 41%. For the contact injuries during games, no action was taken by the referee in 63% of the situation and a red card was shown in 0.5%. The risk of ACL injury was highest early in the football game with 47% sustained during the first 30 min and 24% in the first 15 min. Players changing to a higher level of play 15% had a higher rate of ACL injuries than players changing to a lower level 8%. This difference was especially seen in female football players with 20% of ACL injuries being sustained by players going to a higher division compared to 7% for those going to a lower division. 15% of the male and 21% of the female ACL injuries occurred in teams with a coach change during the season. Knee control exercises to warm up was used by 31% of the female players and 16% of the males. 40% of the players reported that they did not plan on returning to football. CONCLUSION: Neuromuscular training programs have proven to reduce ACL injuries, but greater adherence to these remains a challenge as only 1 in 5 of the ACL-injured football players report using them. Teams changing coach and players going to a higher division appear to have an increased risk of ACL injury warranting attention and further investigations. LEVEL OF EVIDENCE: IV.

Long-term evaluation of pediatric ACL reconstruction: high risk of further surgery but a restrictive postoperative management was related to a lower revision rate.

INTRODUCTION: The guidelines regarding rehabilitation after pediatric anterior cruciate ligament reconstruction (ACLR) are sparse. The aim of the study was to retrospectively describe the long-term outcome regarding further surgery and with special emphasis on the revision rate after two different postoperative rehabilitation programs following pediatric ACLR. MATERIAL AND METHODS: 193 consecutive patients < 15 years of age who had undergone ACLR at two centers, A (n = 116) and B (n = 77), in 2006-2010 were identified. Postoperative rehabilitation protocol at A: a brace locked in 30° of flexion with partial weight bearing for 3 weeks followed by another 3 weeks in the brace with limited range of motion 10°-90° and full weight bearing; return to sports after a minimum of 9 months. B: immediate free range of motion and weight bearing as tolerated; return to sports after a minimum of 6 months. The mean follow-up time was 6.9 (range 5-9) years. The mean age at ACLR was 13.2 years (range 7-14) years. The primary outcome measurement in the statistical analysis was the occurrence of revision. Multivariable logistic regression analysis was performed to investigate five potential risk factors: surgical center, sex, age at ACLR, time from injury to ACLR and graft diameter. RESULTS: Thirty-three percent had further surgery in the operated knee including a revision rate of 12%. Twelve percent underwent ACLR in the contralateral knee. The only significant variable in the statistical analysis according to the multivariable logistic regression analysis was surgical center (p = 0.019). Eight percent of the patients at center A and 19% of the patients at B underwent ACL revision. CONCLUSIONS: Further surgery in the operated knee could be expected in one third of the cases including a revision rate of 12%. The study also disclosed a similar rate of contralateral ACLR at 12%. The revision rate following pediatric ACLR was lower in a center which applied a more restrictive rehabilitation protocol. LEVEL OF EVIDENCE: Case-control study, Level III.

Effect of Concomitant Meniscal Lesions and Meniscal Surgery in ACL Reconstruction With 5-Year Follow-Up: A Nationwide Prospective Cohort Study From Norway and Sweden of 8408 Patients.

BACKGROUND: Increased knowledge of the factors predicting outcome after anterior cruciate ligament reconstruction (ACLR) is needed. PURPOSE: To determine the effect of concomitant meniscal lesions, and the surgical management thereof, on patient-reported outcomes 5 years after ACLR. STUDY DESIGN: Prospective cohort study; Level of evidence, 2. METHODS: A total of 15,706 patients who underwent primary unilateral ACLR between 2005 and 2008 were enrolled prospectively and evaluated longitudinally. All patients were part of the Norwegian and Swedish national knee ligament registries. Outcomes at 5-year follow-up were evaluated with the Knee injury and Osteoarthritis Outcome Score (KOOS). A multivariable linear regression model was used to assess possible effects on prognosis, as measured by KOOS, of a concomitant meniscal lesion and its associated surgical treatment. RESULTS: At a mean follow-up of 5.1 ± 0.2 years, KOOS data were available from 8408 patients: 4774 (57%) patients with no and 3634 (43%) patients with concomitant meniscal lesions (mean patient age, 33.8 ± 10.7 years). Patients with concomitant meniscal lesions reported equal crude mean scores compared with patients without meniscal lesions in all KOOS subscales 5 years after ACLR. The mean improvement in scores from preoperative to the 5-year follow-up was greater for patients with a concomitant meniscal lesion for the KOOS Pain, Activities of Daily Living (ADL), and Sport and Recreation subscales. In the adjusted regression analyses, using patients without concomitant meniscal lesions as the reference, neither no treatment nor resection or repair of medial meniscal lesions were significantly associated with KOOS scores 5 years after ACLR. Except for the ADL subscale, in which a repaired lateral meniscal lesion was associated with better outcome, no significant associations between any of the lateral meniscal lesion treatment categories and KOOS outcome at 5-year follow-up were identified. CONCLUSION: Concomitant meniscal lesions at the time of ACLR conferred no negative effects on patient-reported outcomes 5 years after ACLR. The improvement in selected KOOS subscales from preoperative to the 5-year follow-up was significantly greater for patients with concomitant meniscal lesions than for patients without such lesions.

Risk Factors for Septic Arthritis After Anterior Cruciate Ligament Reconstruction: A Nationwide Analysis of 26,014 ACL Reconstructions.

BACKGROUND: Septic arthritis (SA) after anterior cruciate ligament reconstruction (ACLR) is a rare yet severe complication. The samples in previous studies have been small and without nationwide coverage, making analysis uncertain with a risk of bias. Conclusions to recommend preventive measures are therefore difficult to draw, and it has not been possible to perform a comprehensive risk factor analysis. PURPOSE: To study the incidence of SA after ACLR in a large, nationwide population and to study the risk factors for SA after ACLR. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: All ACLRs, primary and revision, in the Swedish Knee Ligament Registry between 2006 and 2013 were linked with data from the Swedish National Board of Health and Welfare. The incidence of SA events was determined using entries from the day of surgery until 90 days postoperatively based on diagnosis codes and the prescription of antibiotics. All events of SA were verified via a review of medical records. Risk factors were analyzed based on data from the registries. Descriptive statistics were used to describe the findings, while logistic regression analysis was used for the risk analysis. RESULTS: The cohort consisted of 26,014 primary and revision ACLRs. During the study period, 298 events of SA (1.1%) were identified. The high-volume units (≥500 ACLRs during the study period) had a distribution of SA between 2 and 47 (0.2%-2.9%). Independent risk factors of SA were male sex (OR, 1.65; 95% CI, 1.28-2.13), operating time ≥70 minutes (OR, 1.83; 95% CI, 1.42-2.36), hamstring tendon autograft (OR, 2.23; 95% CI, 1.21-4.08), and clindamycin as perioperative antibiotic prophylaxis (OR, 1.94; 95% CI, 1.10-3.41). CONCLUSION: The incidence of SA after ACLR in this nationwide cohort was 1.1%. Male sex, hamstring tendon autografts, and a longer operating time were all independent risk factors for SA. The use of clindamycin as perioperative antibiotic prophylaxis was a risk factor compared with the use of cloxacillin. Some high-volume units had a very low infection rate (0.2%).

Age, time from injury to surgery and quadriceps strength affect the risk of revision surgery after primary ACL reconstruction.

PURPOSE: To identify preoperative, intraoperative and postoperative factors associated with revision anterior cruciate ligament reconstruction (ACLR) within 2 years of primary ACLR. METHODS: Patients who underwent primary ACLR at our institution, from January 2005 to March 2017, were identified. The primary outcome was the occurrence of revision ACLR within 2 years of primary ACLR. Univariate and multivariate logistic regression analyses were used to evaluate preoperative [age, gender, body mass index (BMI), time from injury to surgery, pre-injury Tegner activity level], intraoperative [graft type, graft diameter, medial meniscus (MM) and lateral meniscus (LM) resection or repair, cartilage injury] and postoperative [side-to-side (STS) anterior laxity, limb symmetry index (LSI) for quadriceps and hamstring strength and single-leg-hop test performance at 6 months] risk factors for revision ACLR. RESULTS: A total of 6,510 primary ACLRs were included. The overall incidence of revision ACLR within 2 years was 2.5%. Univariate analysis showed that age < 25 years, BMI < 25 kg/m2, time from injury to surgery < 12 months, pre-injury Tegner activity level ≥ 6, LM repair, STS laxity > 5 mm, quadriceps strength and single-leg-hop test LSI of ≥ 90% increased the odds; whereas, MM resection and the presence of a cartilage injury reduced the odds of revision ACLR. Multivariate analysis revealed that revision ACLR was significantly related only to age < 25 years (OR 6.25; 95% CI 3.57-11.11; P < 0.001), time from injury to surgery < 12 months (OR 2.27; 95% CI 1.25-4.17; P = 0.007) and quadriceps strength LSI of ≥ 90% (OR 1.70; 95% CI 1.16-2.49; P = 0.006). CONCLUSION: Age < 25 years, time from injury to surgery < 12 months and 6-month quadriceps strength LSI of ≥ 90% increased the odds of revision ACLR within 2 years of primary ACLR. Understanding the risk factors for revision ACLR has important implications when it comes to the appropriate counseling for primary ACLR. In this study, a large spectrum of potential risk factors for revision ACLR was analyzed in a large cohort. Advising patients regarding the results of an ACLR should also include potential risk factors for revision surgery. LEVEL OF EVIDENCE: III.

Knee laxity and functional knee outcome after contralateral ACLR are comparable to those after primary ACLR.

PURPOSE: To evaluate and compare knee laxity and functional knee outcome between primary and contralateral anterior cruciate ligament (ACL) reconstruction. METHODS: Patients who underwent primary and subsequent contralateral ACL reconstruction (ACLR) at Capio Artro Clinic, Stockholm, Sweden, from 2001 to 2017, were identified in our local database. The inclusion criteria were: the same patients who underwent primary and contralateral hamstring tendon or bone-patellar tendon-bone autograft ACLR and no associated ligament injuries. The KT-1000 arthrometer, with an anterior tibial load of 134 N, was used to evaluate knee laxity preoperatively and 6 months postoperatively. The Knee injury and Osteoarthritis Outcome Score (KOOS) was collected preoperatively and at the 1-year follow-up. RESULTS: A total of 326 patients with isolated primary and contralateral ACLR met the inclusion criteria (47.9% males; mean age at primary ACLR 23.9 ± 9.4 years and contralateral ACLR 27.9 ± 10.1 years). The arthrometric laxity measurements were available for primary and contralateral ACLR for 226 patients. The mean preoperative and postoperative anterior tibial translation (ATT), as well as the mean ATT reduction from preoperatively to postoperatively, did not differ significantly between primary and contralateral ACLR. The KOOS was available for primary and contralateral ACLR for 256 patients. No significant differences were found preoperatively and at the 1-year follow-up between primary and contralateral ACLR for any of the five KOOS subscales. CONCLUSION: The findings in this study showed that anterior knee laxity and functional knee outcome after contralateral ACLR are comparable to those after primary ACLR. It is important for clinicians to counsel patients about their expectations after contralateral ACLR. This study shows that the results after contralateral ACLR in terms of knee laxity and functional knee outcome are predictable and likely to be comparable to those after primary ACLR. LEVEL OF EVIDENCE: Level III.

How to translate and locally adapt a PROM. Assessment of cross-cultural differential item functioning.

Translating patient-reported outcome measures (PROMs) can alter the meaning of items and undermine the PROM's psychometric properties (quantified as cross-cultural differential item functioning [DIF]). The aim of this paper was to present the theoretical background for PROM translation, adaptation, and cross-cultural validation, and assess how PROMs used in sports medicine research have been translated and adapted. We also assessed DIF for the Knee Injury and Osteoarthritis Outcome Score (KOOS) across Danish, Norwegian, and Swedish versions. We conducted a search in PubMed and Scopus to identify the method of translation, adaptation, and validation of PROMs relevant to musculoskeletal research. Additionally, 150 preoperative KOOS questionnaires were obtained from the Scandinavian knee ligament reconstruction registries, and cross-cultural DIF was evaluated using confirmatory factor analysis and Rasch analysis. There were 392 studies identified, describing the translation of 61 PROMs. Ninety-four percent were performed with forward-backward technique. Forty-nine percent used cognitive interviews to ensure appropriate wording, understandability, and adaptation to the target culture. Only two percent were validated according to modern test theory. No study assessed cross-cultural DIF. One KOOS subscale showed no cross-cultural DIF, two had DIF with respect to some (but not all) items, and thus conversion tables could be constructed, and two KOOS subscales could not be pooled. Most PROM translations are of undocumented quality, despite the common conclusion that they are valid and reliable. Scores from three of five KOOS subscales can be pooled across the Danish, Norwegian, and Swedish versions, but two of these must be adjusted for DIF.

Delayed Anterior Cruciate Ligament Reconstruction Increases the Risk of Abnormal Prereconstruction Laxity, Cartilage, and Medial Meniscus Injuries.

PURPOSE: To determine the association between a delay in anterior cruciate ligament reconstruction (ACLR), age, sex, body mass index (BMI) and cartilage injuries, meniscus injuries, meniscus repair, and abnormal prereconstruction laxity. METHODS: Patients who underwent primary ACLR at our institution from January 2005 to March 2017, with no associated ligament injuries, were identified. Logistic regression analyses were used to evaluate whether delay in ACLR, age, sex, and BMI were risk factors for cartilage and meniscus injuries, meniscus repair, and abnormal (side-to-side difference >5 mm) prereconstruction laxity. RESULTS: A total of 3976 patients (mean age 28.6 ± 10.6 years, range 10-61 years) were included. The risk of cartilage injury increased with a delay in ACLR (12-24 months: odds ratio [OR] 1.20; 95% confidence interval [CI] 1.05-1.29; P = .005; and > 24 months: OR 1.20; 95% CI 1.11-1.30; P < .001) and age ≥30 years (OR 2.27; 95% CI 1.98-2.60; P < .001). The risk of medial meniscus (MM) injury increased with a delay in ACLR (12-24 months: OR 1.20; 95% CI 1.07-1.29; P = .001; and >24 months: OR 1.22; 95% CI 1.13-1.30; P < .001), male sex (OR 1.16; 95% CI 1.04-1.30; P = .04) and age ≥30 years (OR 1.20; 95% CI 1.04-1.33; P = .008). The risk of lateral meniscus (LM) injury decreased with a delay in ACLR of >3 months and age ≥30 years (OR 0.75; 95% CI 0.66-0.85; P < .001), whereas it increased with male sex (OR 1.32; 95% CI 1.22-1.41; P < .001). MM repairs relative to MM injury decreased with a delay in ACLR (6-12 months: OR 0.70; 95% CI 0.54-0.92; P = .01; 12-24 months: OR 0.69; 95% CI 0.57-0.85; P < .001; >24 months: OR 0.61; 95% CI 0.52-0.72; P < .001) and age ≥30 years (OR 0.60; 95% CI 0.48-0.74; P < .001). LM repairs relative to LM injury only decreased with age ≥30 years (OR 0.34; 95% CI 0.26-0.45; P < .001). The risk of having abnormal knee laxity increased with a delay in ACLR of >6 months and MM injury (OR 1.52; 95% CI 1.16-1.97; P = .002), whereas it decreased with a BMI of ≥25 (OR 0.68; 95% CI 0.52-0.89; P = .006). CONCLUSIONS: A delay in ACLR of >12 months increased the risk of cartilage and MM injuries, whereas a delay of >6 months increased the risk of abnormal prereconstruction laxity and reduced the likelihood of MM repair. To reduce meniscus loss and the risk of jeopardizing knee laxity, ACLR should be performed within 6 months after the injury. LEVEL OF EVIDENCE: Level III, retrospective therapeutic comparative study.

Can Talented Youth Soccer Players Who Have Undergone Anterior Cruciate Ligament Reconstruction Reach the Elite Level?

BACKGROUND: Anterior cruciate ligament (ACL) ruptures are common in soccer players, and reconstructive surgery is often performed to restore knee stability and enable a return to play. PURPOSE: To investigate whether an ACL reconstruction for talented youth soccer players affects their potential to become elite players at the senior level. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: All soccer players who participated in the Swedish National Elite Camp for 15-year-old players between 2005 and 2011 (N = 5285 players; 2631 boys and 2654 girls) were matched with the Swedish National Knee Ligament Registry to identify the players who had undergone ACL reconstruction. Information on player participation in Swedish league games and level of play was collected from the Swedish Football Association's administrative data system. The players with an ACL reconstruction who were injured at the ages of 15 to 19 years were compared with the rest of the players who participated in the National Elite Camp to see whether an early ACL reconstruction affected whether they remained active as soccer players and their chance to play at the elite level as seniors. RESULTS: A total of 524 (9.9%) players had undergone an ACL reconstruction, and 292 (5.5%; 75 male and 217 female) had sustained their injury at age 15 to 19 years. During the follow-up period, 122 (23.3%) players underwent ACL reconstruction: revision (11.5%; n = 60) or contralateral (11.8%; n = 62). Male and female soccer players undergoing an ACL reconstruction at age 15 to 19 years experienced no significant effect on being active or playing at the elite level in the season that they turned 21 years old. Of the youth players who underwent ACL reconstruction, 12% of the male players and 11.5% of the female players progressed to the elite level at the age of 21 years compared with 10.3% of the men and 11.1% of the women among the uninjured players. CONCLUSION: ACL reconstructive surgery in talented youth soccer players offers them the opportunity to become elite players as seniors and permits an activity level on a par with that of their uninjured peers. However, almost 1 in 4 requires further ACL surgery, so the players' future knee health should be considered when deciding on a return to play.

One sixth of primary anterior cruciate ligament reconstructions may undergo reoperation due to complications or new injuries within 2 years.

PURPOSE: To analyse the incidence, types and risk factors for reoperation within 2 years of primary anterior cruciate ligament reconstruction (ACLR). METHODS: Our clinic registry was used to identify primary ACLRs, performed from 2005 to 2015, and reoperations performed on the ipsilateral knee within 2 years at our institution. Reoperations were identified using procedural codes and analysis of medical records. A logistic regression analysis was used to evaluate risk factors for reoperation. RESULTS: A total of 6030 primary ACLRs were included. A total of 1112 (18.4%) reoperations performed on 1018 (16.9%) primary ACLRs were identified. The most common reoperations were screw removal (n = 282, 4.7%), meniscus procedures (n = 238, 3.9%), cyclops removal/notchplasty (n = 222, 3.7%) and reoperations due to graft rupture (n = 146, 2.4%), including revision ACLR. Age < 30 years (OR 1.57; 95% CI 1.37-1.80; P < 0.001), female gender (OR 1.33; 95% CI 1.17-1.51; P < 0.001), medial meniscus repair (OR 1.55; 95% CI 1.23-1.97; P < 0.001), lateral meniscus resection (OR 1.26; 95% CI 1.07-1.49; P = 0.005) and lateral meniscus repair (OR 1.38; 95% CI 1.03-1.85; P = 0.02) at primary ACLR were found to be risk factors for reoperation. CONCLUSION: One sixth of all primary ACLRs underwent reoperation due to complications or new injuries within 2 years. The most common reoperations were screw removal, meniscus procedures, cyclops removal/notchplasty and reoperations due to graft rupture, including revision ACLR. Younger age (< 30 years), female gender, medial meniscus repair and lateral meniscus resection or repair at primary ACLR were associated with an increased risk of reoperation. This study provides clinicians with important data to inform patients about the short-term reoperation rates, the most common reoperation procedures and risk factors for reoperation after primary ACLR. LEVEL OF EVIDENCE: III.

There is no general use of thromboprophylaxis and prolonged antibiotic prophylaxis in anterior cruciate ligament reconstruction: a nation-wide survey of ACL surgeons in Sweden.

PURPOSE: The use of prophylaxis for thromboembolism and infection in anterior cruciate ligament (ACL) reconstruction is not well documented and no general guidelines have been established. The aim of this study was to evaluate the ACL surgeons' individual strategies of thromboprophylaxis, use of prolonged antibiotic prophylaxis and vancomycin-soaked ACL grafts, and if its use is supported in the current literature. Additionally, the rationale for use of tourniquet was analysed. METHODS: Questionnaires were distributed to all Swedish ACL surgeons who are registered in the Swedish Knee Ligament Register (SKLR), asking about prescription of thromboprophylaxis, prolonged antibiotic prophylaxis, the use of vancomycin-soaked graft and the use of a tourniquet during surgery. The responses were assessed for agreement and the thromboprophylaxis data were analysed in relation to the 2016 SKLR data. RESULTS: 115 (75%) ACL surgeons responded to the survey. 81.7% prescribed thromboprophylaxis only when risk factors, such as history of thrombosis and the use of oral contraceptives, were present. Female gender, older age and admitted patient were considered the risk factors with the lowest impact. The respondents were generally restrictive regarding the use of prolonged antibiotic prophylaxis. The use of vancomycin-soaked graft was used by only nine (8%) surgeons representing 406 (13%) of the surgeries. CONCLUSION: Swedish ACL surgeons are generally restrictive using thromboprophylaxis and only when risk factors are present. However, there is a lack of consensus in how to weigh the different risk factors and it does not completely adhere to the existing literature. Prolonged antibiotic prophylaxis is rarely used and the use of vancomycin soaking of graft is very limited and applies only to a small number of surgeons. The use of tourniquet is common. There is a need for ACL-specific guidelines regarding the use of thromboprophylaxis. LEVEL OF EVIDENCE: IV.

High Risk of Further Anterior Cruciate Ligament Injury in a 10-Year Follow-up Study of Anterior Cruciate Ligament-Reconstructed Soccer Players in the Swedish National Knee Ligament Registry.

PURPOSE: To follow up on soccer players 10 years after a primary anterior cruciate ligament (ACL) reconstruction to find out how many players returned to play soccer, what influenced their decision, and if there are any differences in additional ACL injuries (graft failure and/or contralateral ACL injury) between those who returned to play and those who did not. METHODS: The study cohort consists of 1661 soccer players from the Swedish National Knee Ligament Registry. A questionnaire was sent to each player regarding their return to play and additional knee injuries that may have occurred 10 years after their primary ACL. The results are based on the 684 responders. Data such as age, sex, surgical procedural data, associated injuries, patient-reported outcome measures, and additional knee surgeries were collected from the registry. RESULTS: In this study, 51% returned to play soccer. For those who did not return to play, the primary reason was knee related (65.4% of the cases). The most common knee-related reasons for not returning were pain and/or instability (50%; n = 109), followed by fear of reinjury (32%; n = 69). Players who return to soccer have a significantly higher risk of additional ACL injury. Of the players who returned to play soccer, 28.7% (odds ratio [OR] 2.3, P < .001) had additional ACL injury, 9.7% (OR 2.9, P < .001) had a graft failure and 20.6% (OR 2.1, P < .001) had a contralateral ACL injury. CONCLUSIONS: Players that return to soccer have a significantly higher risk of sustaining further ACL injury. Only half of the soccer players return to play after ACL reconstruction, and in two-thirds of those who did not return, the reason was knee related. The high risk of sustaining additional knee injury is of serious concern to the player's future knee health and should be considered when deciding on a return to play. LEVEL OF EVIDENCE: Level III retrospective case-control study.