Riccardo Cristiani

Purpose: To assess the prevalence of, and factors associated with, meniscal ramp lesions in patients with anterior cruciate ligament (ACL) tears. Methods: All patients who underwent primary ACL reconstruction (ACLR) during 2018 were evaluated. Preoperative magnetic resonance imaging (MRI) scans and surgical reports were reviewed searching for the presence of meniscal ramp lesions. The Greif classification was applied to MRI‐detected lesions. Univariable and multivariable logistic regression analyses, and a backward logistic regression analysis, were used to evaluate the associations between patient characteristics and concomitant knee injuries and the presence of meniscal ramp lesions on MRI and at ACLR, respectively. Results: Of the 579 patients included in this study (51.0% men; mean age 28.4 ± 11.4), 250 (43.2%) meniscal ramp lesions were diagnosed on MRI, and 57 (9.8%) were diagnosed at ACLR. None of the 25 MRI‐detected Greif´s type 1 and 2 meniscal ramp lesions were confirmed intraoperatively. Posteromedial tibial bone bruising increased likelihood of having meniscal ramp lesions on MRI (odds radio 4.04, 95% confidence intervals 2.85‐5.76; P < .001) and at ACLR (odds radio 2.29, 95% confidence intervals 1.29‐4.19; P < .01). Conclusions: Meniscal ramp lesions were frequently detected on MRI in patients undergoing ACL reconstruction, although less commonly observed at the time of surgery. MRI‐detected stable meniscal ramp lesions according to the Greif classification (type 1 and 2) showed poor surgical correlation, with no lesions identified at subsequent arthroscopy. Posteromedial tibial bone bruising on MRI was associated with the presence of meniscal ramp lesions both on MRI and at surgery. Level of Evidence: Level III, retrospective cohort study.

Background/Objectives: Early patellofemoral osteoarthritis (PFOA) following anterior cruciate ligament reconstruction (ACLR) is increasingly recognized as an important contributor to knee osteoarthritis (OA) in young individuals. This narrative review aimed to summarize the current evidence on early PFOA following ACLR including its prevalence, definition, risk factors, treatment, ongoing research, and future directions. Methods: A non-systematic literature search of PubMed/MEDLINE was conducted for English-language peer-reviewed original studies and reviews on early PFOA following ACLR, published through May 2026. Titles and abstracts were screened for relevance and full-text articles were reviewed when appropriate. ClinicalTrials.gov was searched for ongoing randomized controlled trials (RCTs). Results: Early PFOA following ACLR had a prevalence of 17–44% within 5 years postoperatively. Definitions remain highly heterogeneous with no universally accepted classification, although MRI-based assessment tools such as the MRI Osteoarthritis Knee Score (MOAKS) appear to be increasingly utilized. Proposed risk factors include older age, higher body mass index, concomitant meniscal injury, quadriceps weakness, altered biomechanics, and autograft choice, although findings remain inconsistent across studies. Current prevention and treatment strategies are largely extrapolated from general knee OA principles, reflecting the limited evidence specific to early PFOA. Ongoing research is increasingly focused on rehabilitation-based prevention and pharmacological interventions targeting early OA following ACLR. Conclusions: Early PFOA following ACLR is common in young individuals, yet evidence regarding its definition, risk factors, prevention, and treatment remains limited. The early disease stage may allow modification of structural and biomechanical changes, enabling disease-modifying pharmacological and targeted rehabilitation approaches, but standardized classification criteria and future research are needed.

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.

The menisci play a critical role in load transmission and shock absorption and serve as important secondary stabilizers of the knee. Unfortunately, meniscal repair is not always feasible, and resection may be required. Meniscal allograft transplantation is an established method of meniscal substitution; however, its use remains limited by graft sizing challenges, high costs, and restricted availability. The semitendinosus tendon has the capacity to remodel and revascularize within the intra‐articular environment. The purpose of this technical note is to describe the surgical technique for meniscal substitution using a semitendinosus tendon autograft.

Purpose: To identify factors associated with knee extension loss prior to anterior cruciate ligament (ACL) reconstruction (ACLR). Methods: Patients without concomitant ligament injuries who underwent primary ACLR at the Capio Artro Clinic, Stockholm, Sweden, between 1 January 2002 and 31 December 2023, were eligible for inclusion. The outcome of the study was the presence of preoperative extension loss, defined as a deficit of ≥5 degrees prior to ACLR. Univariable and multivariable logistic regression analyses were conducted to assess associations between the study outcome and the following variables: age at surgery, sex, time from injury to surgery, preinjury Tegner activity level, cartilage injury, medial meniscus or lateral meniscus injury, and physiologic contralateral knee extension deficit (≥5 degrees). Results: A total of 10,692 patients were included. The overall incidence of extension loss prior to ACLR was 6.3% (677/10,692). Multivariable logistic regression analysis showed that early surgery (≤3 months) (odds ratio [OR]: 2.94; 95% confidence interval [CI]: 2.43–3.57; p < 0.001), medial meniscus injury (OR: 1.30; 95% CI: 1.07–1.57; p = 0.01), lateral meniscus injury (OR: 1.23; 95% CI: 1.01–1.48; p = 0.04) and physiologic contralateral knee extension deficit (OR: 34.38; 95% CI: 25.36–46.61; p < 0.001) were associated with increased odds of extension loss prior to ACLR. No associations were found between preoperative extension loss and age at surgery, sex, preinjury Tegner activity level, or the presence of a cartilage injury. Conclusions: Preoperative extension loss was observed in 6.3% of the patients undergoing ACLR. Early surgery (≤3 months), medial or lateral meniscal injury, and physiologic contralateral knee extension deficit were associated with increased odds of preoperative extension loss. Awareness of these factors may assist clinicians identify patients at risk for extension loss and optimise preoperative management strategies prior to ACLR. Level of Evidence: Level III.

Purpose: To determine the proportion of patients and the factors associated with the achievement of a patient‐acceptable symptom state (PASS) 5 years after primary anterior cruciate ligament reconstruction (ACLR). Methods: Patients who underwent primary ACLR between 2005 and 2018 at Capio Artro Clinic, Stockholm, Sweden, were eligible for inclusion. The primary outcome was the achievement of a PASS on each Knee injury and Osteoarthritis Outcome Score (KOOS) subscale at the 5‐year follow‐up. Multivariable logistic regression analyses were used to assess associations with age, sex, time from injury to surgery, pre‐injury Tegner activity level, graft type, cartilage injury, meniscal resection or repair, and symmetrical 6‐month limb symmetry index (LSI ≥ 90%) in isokinetic extension and flexion strength and single‐leg‐hop performance. Results: A total of 2663 patients were analysed. The proportion of patients achieving a PASS varied between the KOOS subscales as follows: pain 64.8%; symptoms 93.8%; activities of daily living (ADL) 49.1%; sport and recreation (Sport&Rec) 65.4% and quality of life (QoL) 73.5%. Age ≥30 years was positively associated with PASS across all subscales. Female sex reduced the odds of achieving a PASS on the pain (OR 0.80; 95% confidence interval [CI] 0.65–0.99; p = 0.04), symptoms (OR 0.57; 95% CI 0.36–0.90; p = 0.02) and Sport&Rec (OR 0.73; CI 95% 0.59–0.90; p = 0.004) subscales. A surgical delay of ≥3 months was negatively associated with the achievement of a PASS on the QoL (OR 0.71; 95% CI 0.51–0.99; p = 0.04) subscale. Medial meniscus (MM) repair reduced the odds of achieving a PASS on the Sport&Rec (OR 0.61; 95% CI 0.41–0.92; p = 0.02) and QoL (OR 0.56; 95% CI 0.37–0.86; p = 0.01) subscales. Hamstring tendon (HT) autograft rather than bone‐patellar‐tendon‐bone autograft had increased odds of achieving a PASS on the Sport&Rec (OR 2.13; 95% CI 1.31–3.47; p = 0.002) subscale. Achieving a LSI ≥ 90% in isokinetic extension strength was associated with a PASS on ADL (OR 1.01; 95% CI 1.00–1.02; p = 0.02) and QoL (OR 1.01; 95% CI 1.00–1.02; p = 0.02) subscales, whereas an LSI ≥ 90% in single‐leg‐hop test was associated with a PASS on the symptoms (OR 1.03; 95% CI 1.01–1.05; p < 0.001), ADL (OR 1.01; 95% CI 1.00–1.02; p = 0.02), Sport&Rec (OR 1.01; 95% CI 1.01–1.02; p = 0.003), and QoL (OR 1.01; 95% CI 1.00–1.02; p = 0.01) subscales. Conclusion: The achievement of a PASS was over 64% on at least four out of five KOOS subscales 5 years after ACLR. Older age (≥ 30 years) was consistently associated with higher odds of achieving a PASS, while female sex was associated with lower odds. MM repair was associated with reduced odds of achieving a PASS on the Sport&Rec subscale, whereas the use of HT grafts was associated with higher odds on the same subscale. Symmetrical isokinetic extension strength and single‐leg‐hop test performance at 6 months were associated with higher odds of achieving a PASS; however, the effect sizes were small, suggesting limited clinical relevance. Level of Evidence: Level III.

Purpose: To determine whether preoperative knee laxity, as measured by the KT‐1000 arthrometer, was associated with subjective knee function preoperatively and at 1, 2 and 5 years, or with revision anterior cruciate ligament (ACL) reconstruction (ACLR) within 5 years of the primary surgery.Methods: Patients who underwent primary ACLR using a hamstring tendon autograft at the Capio Artro Clinic, Stockholm, Sweden, between January 1, 2005, and December 31, 2018, and had no associated ligament injuries, were identified. The KT‐1000 arthrometer (134‐N) was used to assess knee laxity preoperatively. The Knee injury and Osteoarthritis Outcome Score (KOOS) was obtained preoperatively and at 1‐, 2‐ and 5‐year follow‐ups. Patients who underwent revision ACLR at any hospital or clinic nationwide within 5 years of their primary surgery were identified via the Swedish Knee Ligament Registry. KOOS subscale scores between groups were compared using analysis of covariance (ANCOVA), while differences in revision ACLR rates were evaluated using Cox regression analysis.Results: A total of 5425 patients (54.0% male) with available preoperative KT‐1000 arthrometer measurements were included: side‐to‐side (STS) ≤ 2 mm, 1833 (33.8%); STS 3–5 mm, 2387 (44.0%); STS > 5 mm, 1205 (22.2%). The only significant differences in subjective knee function among the groups were observed in the preoperative KOOS Symptoms (STS ≤ 2 mm: 75.0 ± 17.4; STS 3–5 mm: 75.1 ± 17.5; STS > 5 mm: 76.4 ± 17.1; P = 0.03) and Pain (STS ≤ 2 mm: 78.9 ± 15.9; STS 3–5 mm: 79.4 ± 15.9; STS > 5 mm: 80.4 ± 15.2; p = 0.02) subscale. No additional significant differences were observed between the groups in any of the KOOS subscales at the preoperative assessment or at the 1‐, 2‐ or 5‐year postoperative follow‐ups. At 5 years postoperatively, the revision ACLR rates were 4.8% (89/1833) in the STS ≤ 2 mm group, 4.9% (118/2387) in the STS 3–5 mm group and 6.0% (73/1205) in the STS > 5 mm group. The hazard of revision ACLR within 5 years did not differ significantly from the reference group (STS ≤ 2 mm) for either the STS 3–5 mm group (hazard ratio [HR], 0.96; 95% confidence interval [CI], 0.69–1.35; P = n.s.) or the STS > 5 mm group (HR, 1.19; 95% CI, 0.89–1.60; P = n.s.). The incidence of medial meniscus injury increased progressively across the laxity groups from 20.7% in the STS ≤ 2 mm group, to 25.0% in the STS 3‐5 mm group and 31.9% in the STS > 5 mm group.Conclusions: The degree of preoperative knee laxity, as measured by the KT‐1000 arthrometer, was not associated with postoperative subjective knee function or revision ACLR within 5 years of primary surgery. Medial meniscus injuries were associated with greater preoperative knee laxity. The findings of this study suggest that preoperative arthrometric knee laxity should not be considered as a prognostic factor for ACLR outcomes.Level of Evidence: Level III.