Alexander Sandon

Background: Return to competition (RTC) after anterior cruciate ligament reconstruction (ACLR) is frequently reported, but long-term football participation following return remains poorly described. Objective: The aim was to describe RTC rates after primary ACLR in football players and to evaluate post-RTC career sustainability, quantified by the number of matches and seasons played, across sex, age, and pre-injury level. Methods: In this decade-long nationwide cohort study, football players undergoing primary ACLR between 2014 and 2023 were identified in the Swedish Knee Ligament Registry and linked to the Swedish Football Association’s match database. RTC was defined as participation in one or more official match after surgery. Analyses of post-RTC match and season participation were restricted to players who returned by the 2022 season or earlier, allowing a minimum potential follow-up of three seasons. Outcomes were compared across sex, age groups, and pre-injury level using non-parametric methods. Results: A total of 10,836 football players were included, of whom 6339 (58.5%) achieved RTC. RTC rates varied across pre-injury competitive levels, ranging from 90.4% at the top level to 35.9% at the recreational level ( p < 0.001). Among players with sufficient follow-up ( n = 4749), median post-RTC participation was 31 matches (interquartile range [IQR] 11–70) across three seasons (IQR 2–5). Men accumulated more matches after RTC than women (33 vs 29; p = 0.017) and remained active for more seasons (4 vs 3; p < 0.001). Pre-injury competitive level was strongly associated with career sustainability ( p < 0.001): top-level players accumulated a median of 97 matches (IQR 42–148) across five seasons (IQR 3–6), whereas players competing at lower levels accumulated fewer matches and seasons. Age-related differences were significant in men but not in women. Conclusion: Football career sustainability following primary ACLR was greatest among players competing at higher pre-injury levels and, to a lesser extent, among men. Although RTC was commonly achieved, long-term participation after return was often limited, indicating that RTC alone provides an incomplete description of football participation after ACLR.

Objective To determine whether autograft type (hamstring, patellar or quadriceps tendon) is associated with risk of revision anterior cruciate ligament reconstruction (ACLR) or contralateral ACLR in football players. Methods Nationwide cohort included all primary ACLRs performed in registered football players in Sweden between 2014 and 2023, identified by linkage of the Swedish Knee Ligament Registry and the Swedish Football Association. Return to competition (RTC) was defined as participation in at least one official match. Outcomes were revision ACLR (index knee) and contralateral ACLR. Sex stratified, cause specific Cox models adjusted for age and pre-injury level of play (Elite, Non-elite, Youth) were used, with hamstring tendon as graft reference. Results A total of 10 693 players were included, of whom 6238 (58%) RTC, mean age 22±7 years, mean follow up 5.2±2.9 years. Among RTC players, revision ACLR occurred in 232 women (10.8%) and in 349 (9.2%) men with no association between graft type and revision ACLR. Contralateral ACLR occurred in 263 women (12.2%) and 264 (6.9%) men. In women, quadriceps tendon was associated with a higher hazard of contralateral ACLR (HR 1.98, 95% CI 1.17 to 3.36). No graft-specific differences were seen in age-restricted sensitivity analyses or in the full cohort. Younger age and higher pre-injury level were consistently associated with greater subsequent ACLR risk. Conclusions Graft choice was not independently associated with revision ACLR, including among young football players who RTC. An association between quadriceps tendon autograft and contralateral ACLR was observed among women. Across analyses, age and pre-injury level of play were the most consistent correlates of subsequent ACLR risk.

Purpose: The management of cartilage lesions encountered during anterior cruciate ligament reconstruction (ACLR) remains debated, with limited evidence on whether surgical treatment affects lesion progression or outcomes. This study aimed to compare structural progression and clinical outcomes of isolated cartilage lesions treated or left untreated during primary ACLR, using data from the Swedish Knee Ligament Registry (SKLR). Methods: Patients who underwent both primary and revision ACLR between 2005 and 2024 were identified in the SKLR. Inclusion required an isolated cartilage lesion documented arthroscopically at primary ACLR. Multi‐compartment lesions and multi‐ligament procedures were excluded. A 1:1 matched analysis compared patients who underwent surgical cartilage treatment (debridement or microfracture) with untreated patients. Structural evolution was assessed by comparing arthroscopic findings at primary and revision ACLR and classified as stable, progressed or regressed based on International Cartilage Repair Society (ICRS) grade and lesion size. Secondary analyses included 2‐year revision‐free survival and patient‐reported outcomes (Knee injury and Osteoarthritis Outcome Score, EuroQol 5‐Dimension questionnaire, EuroQol Visual Analogue Scale) in patients without revision within 2 years. Results: A matched cohort of 156 patients (78 treated and 78 untreated) was included. Baseline characteristics were comparable, except for operated side ( p = 0.007). At revision ACLR, treated patients showed higher lesion stability than untreated patients (21.8% vs. 5.1%; p = 0.005). This effect was significant in low‐grade lesions (ICRS I–II), with higher stability (27.1% vs. 5.1%; p = 0.002) and lower progression (15.3% vs. 32.2%; p = 0.050), while no differences were observed in high‐grade lesions. Two‐year revision‐free survival was comparable (log‐rank p = 0.53). Among patients without revision ( n = 88), both groups improved in patient‐reported outcome measures with no between‐group differences. Conclusions: Surgical treatment of isolated cartilage lesions during primary ACLR was associated with greater structural stability at revision surgery, particularly in low‐grade lesions, without superior short‐term clinical outcomes. These findings suggest structural benefits may not translate into early improvement. Level of Evidence: Level II, prospective comparative study.

Purpose: To evaluate the association between hamstring autograft diameter and the risk of revision anterior cruciate ligament reconstruction (ACLR) in football players, and to determine whether this relationship differs according to sex and height. Methods: A nationwide registry‐linked cohort was assembled by combining the Swedish Knee Ligament Registry and the Swedish Football Association's competition database. Football players undergoing primary index ACLR with hamstring autograft between 2014 and 2023 were eligible. Graft diameter was categorised ≤7.5, 8.0, 8.5, ≥9.0 mm with ≥9.0 mm as the reference group. Estimated adjusted hazard ratios (HRs) for revision were calculated with Cox models, stratified by sex and predefined height groups, a secondary analysis restricted to players who returned to official match play (RTC) were also performed. Results: A total of 9448 players were included, 6127 (65%) men. During follow‐up, 771 revision ACLR occurred (8.2%). Crude revision risk decreased stepwise with increasing graft diameter: 10.4% for ≤7.5 mm, 9.5% for 8.0 mm, 8.5% for 8.5 mm, and 6.2% for ≥9.0 mm. Among men, diameter‐related risk differences were concentrated in taller players. In those 176–184 cm, grafts ≤7.5 mm showed a 2.27‐fold higher adjusted hazard of revision (95% confidence interval [CI], 1.30–3.94) compared with ≥9.0 mm. In players ≥185 cm, hazards were elevated for both ≤7.5 mm (HR 2.86, 95% CI 1.19–6.85) and 8.0 mm grafts (HR 1.98, 95% CI 1.14–3.42). No significant graft‐diameter effect was identified in men ≤175 cm, nor in any height stratum among women. Findings were consistent in the subgroup restricted to players who returned to official competition. Conclusion: Smaller hamstring autografts are associated with increased revision ACLR risk in tall male football players, whereas no clear graft‐diameter effect is observed in women or shorter men. These findings suggest that graft diameter may be best interpreted in relation to patient height rather than applied as a universal threshold. Level of Evidence: Level III, retrospective cohort study.

Purpose: To determine the incidence of second anterior cruciate ligament (ACL) injuries in football players after index ACL reconstruction (ACLR). Secondary objectives were to assess second ACL injury rates across subgroups (laterality, sex, age, playing level, graft type, return to play [RTP] and follow‐up duration) and to review factors associated with reinjury. Methods: A systematic review and meta‐analysis were conducted according to Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines. PubMed, EMBASE and the Cochrane Library were searched from inception to 10 December 2025. Studies reporting second ACL injuries or subsequent ACLRs in football players were included. Incidence was defined as the proportion of players sustaining a subsequent ACL injury or ACLR relative to those undergoing index ACLR. RTP was defined as participation in at least one official match. Key limitations include substantial heterogeneity across studies, the inclusion of mixed data sources and the operational definition of second ACL injury, combining ACL injuries (graft rupture or contralateral tear) or, when not reported, subsequent ACLRs. Results: Thirty‐four studies (16,905 players; 50.5% male) were included. The pooled incidence of second ACL injury was 21.6% (95% confidence interval [CI] 17.9%–25.9%). Contralateral (10.6%, 95% CI 8.0%–13.9%) and ipsilateral injuries (10.4%, 95% CI 8.4%–12.9%) were of similar magnitude. Higher pooled incidence was observed in female (23.5%, 95% CI 18.0%–30.1%) compared with male players (14.5%, 95% CI 14.5%–23.4%), with 30% increased odds (odds ratio [OR] 1.3, 95% CI 1.1%–1.7%, p < 0.01). Among professionals, incidence was 19.2% (95% CI 15.1%–24.2%). No significant differences were found between hamstring tendon and bone–patellar tendon–bone (BPTB) autografts. The highest rates were observed in players <21 years (31.9%, 95% CI 23.6%–41.6%) and in cohorts with high RTP rates (29.2%, 95% CI 24.7%–34.1%). Conclusion: Second ACL injuries are common in football, affecting roughly between one in three to one in five players after ACLR. Higher rates of second ACL injury were observed in female players, younger individuals, those who returned to play, and in studies with longer follow‐up duration. Contralateral ACL injuries had a similar magnitude to ipsilateral injuries. No significant differences in ipsilateral ACL reinjury rates were found between hamstrings tendon and BPTB autografts. Level of Evidence: Level IV, systematic review and meta‐analysis.

Background: Chondral lesions and subsequent knee osteoarthritis often occur after anterior cruciate ligament (ACL) injuries, and although ACL reconstruction (ACLR) is common, cartilage degeneration remains more prevalent than in the general population, with inconsistent evidence on whether surgery offers a protective effect. Purpose/Hypothesis: This study aimed to evaluate the progression of cartilage damage after ACLR using second-look arthroscopy in patients who underwent both primary and revision procedures and to identify risk factors for cartilage degeneration. It was hypothesized that chondral lesions would progress between primary and revision surgery, primarily influenced by characteristics of the initial injury and primary surgery. Study Design: Cohort study; Level of evidence, 3. Methods: A retrospective cohort study was conducted using prospectively collected data from the Swedish Knee Ligament Registry. All patients who underwent both primary and revision ACLR between January 1, 2005, and December 31, 2023, were included. Patients with multiligament injuries or missing key data were excluded. The prevalence, location, and severity of cartilage lesions assessed intraoperatively at both primary and revision ACLR were reported and compared. Secondarily, potential risk factors for cartilage damage at the time of revision surgery were evaluated using multivariate logistic regression analysis, incorporating available patient and surgical variables from the registry. Results: A total of 2845 patients were included. The prevalence, size, and severity of cartilage lesions increased markedly across all knee compartments between primary and revision ACLR, which occurred at a median of 2.4 years later. We found 4 independent risk factors for cartilage damage at revision surgery: older age, meniscal and cartilage lesions at primary surgery, and longer time from primary injury to revision ACLR. Each additional month from the initial injury to revision ACLR was associated with a 0.7% increase in the odds of cartilage damage, underscoring a time-dependent degenerative process. Conclusion: This study showed a clear progression of cartilage degeneration between primary and revision ACLR. Although limited to patients requiring revision surgery, these findings contribute to the broader understanding of posttraumatic joint deterioration and reinforce the need for interdisciplinary approaches to mitigate long-term cartilage damage.

Purpose: To compare anteromedial (AM) portal versus transtibial (TT) femoral drilling techniques in football players undergoing anterior cruciate ligament reconstruction (ACLR), focusing on return‐to‐competition (RTC), match exposure, patient‐reported outcomes (PROMs) and reinjury risk. Methods: This nationwide cohort study linked the Swedish Knee Ligament Registry with the Swedish Football Association to capture surgical details, verified football participation, and longitudinal PROMs. All index ACLRs in registered football players from 2017–2023 were included. Outcomes were RTC, match exposure, Knee injury and Osteoarthritis Outcome Score and EuroQol 5 dimension score scores at pre‐op, 1, 2 and 5 years, and revision, contralateral, or any second ACL reconstruction. Analyses used t‐tests and χ ² tests, and Cox regression adjusted for age, sex, injured side, and meniscal and cartilage injury. Results: A total of 7169 football players were included (AM 6,653; TT 516). Group differences at baseline were small but present (e.g., more women and left‐sided injuries in TT; more meniscal repair and cartilage injury in AM). RTC rates were similar (55.2% AM vs. 56.8% TT), as were time to RTC, total matches played, matches after RTC, seasons played, and competitive level before and after injury. PROMs showed modest 1‐year differences favouring AM that were not observed at 2 years. No differences were observed at 5 years, although based on limited TT data. Reinjury rates were comparable (revision 6.7% AM vs. 7.4% TT; contralateral 4.6% vs. 4.8%; any second ACLR 11.0% vs. 11.8%). Adjusted Cox models showed no association between portal technique and revision (hazard ratio [HR] 0.878, 95% confidence interval [CI] 0.63–1.23) or any second ACLR (HR 0.906, 95% CI 0.70–1.18), with similar findings in RTC‐only analyses. Conclusion: In a nationwide cohort of football players, AM and TT femoral drilling techniques yielded similar real‐world outcomes: comparable reinjury risk, RTC rates and timing, match exposure, competitive trajectory, and PROMs. For football players undergoing primary ACL reconstruction, both AM and TT techniques are acceptable options. Level of Evidence: Level III, retrospective cohort study.

Purpose: To evaluate whether meniscal repair reduces the risk of cartilage damage compared with meniscal resection in patients undergoing both primary and revision anterior cruciate ligament reconstruction (ACLR). Methods: This registry‐based cohort study included 2845 patients from the Swedish Knee Ligament Register who underwent both primary and revision ACLR between 2005 and 2023. Cartilage status was assessed arthroscopically at both surgeries. Meniscal treatment at primary ACLR was categorized as repair or resection (medial: 168 resections, 299 repairs; lateral: 486 resections, 162 repairs). The primary outcome was the development of new cartilage lesions at revision. Predictors of new cartilage lesions were analysed using multivariate logistic regression. Results: In the medial femoral condyle, new cartilage lesions occurred in 32.3% of patients after resection and 26.5% after repair (odds ratio [OR]: 0.76, 95% confidence interval [CI]: 0.47–1.21). In the medial tibial plateau, new cartilage lesion rates were 13.5% and 14.0%, respectively (OR: 1.04, 95% CI: 0.61–1.79). In the lateral femoral condyle, cartilage lesions occurred in 12.5% after resection and 14.5% after repair (OR: 1.18, 95% CI: 0.67–2.09), while in the lateral tibial plateau, rates were 8.7% and 7.9% (OR: 0.89, 95% CI: 0.43–1.86). No significant differences were found in lesion size or severity between treatment groups in any location. Multivariate analysis showed that older age, longer time to revision and meniscal treatment (both repair and resection) were associated with higher odds of new cartilage lesions (all p <0.05). Time from injury to primary ACLR was not associated with cartilage outcomes. Conclusion: Meniscal repair did not confer a clear chondroprotective advantage compared with resection in ACLR. Both treatment types were associated with new cartilage lesions, suggesting that meniscal injury itself may be a key contributor to cartilage degeneration. Age and time to revision were strong predictors of cartilage damage. Level of Evidence: Level III, retrospective cohort study.