Purpose The aim of this study was to determine patient and anatomic factors that influence anteroposterior and rotational laxity in knees with ACL tears. Based on the findings of biomechanical studies, we hypothesized that static and dynamic anterior tibial translation (ATT) as well as positive pivot shift would increase with female gender, tibial slope, and meniscal tears. Methods The authors prospectively collected preoperative data and intraoperative findings of 417 patients that underwent ACL reconstruction. The exclusion criteria were: revision ACL procedures (n = 53), other surgical antecedents (n = 27), prior osteotomies (n = 7) or concomitant ligament tears on the ipsilateral knee (n = 34), and history of ACL tears in the contralateral knee (n = 45), leaving a study cohort of 251 patients. Their preoperative anteroposterior knee laxity was assessed objectively using 'static' monopodal weight-bearing radiographs and 'dynamic' instrumented differential measurements of ATT. Rotational laxity was assessed subjectively using the pivot shift test. Results Multivariable regression showed that static ATT increases only with tibial slope (β = 0.30; p < 0.001), but dynamic ATT increases with tibial slope (β = 0.19; p = 0.041), medial meniscal tears (β = 1.27; p = 0.007), complete ACL tears (β = 2.06; p < 0.001), and to decrease with age (β = − 0.09; p < 0.001). Multivariable regression also indicated that high-grade pivot shift decreases with age (OR 0.94; p < 0.001) and for women (OR 0.25; p < 0.001), and to be higher for knees with complete ACL tears (OR 3.04; p = 0.002) or medial meniscal tears (OR 2.28; p = 0.010). Conclusion Contrary to expectations based on biomechanical studies, static ATT was only affected by high posterior tibial slope, while dynamic ATT was affected by both high posterior tibial slopes and medial meniscal tears, but not by gender or lateral meniscal tears. Likewise, pivot shift was affected by gender and medial meniscal tears, but not lateral meniscal tears or posterior tibial slope. These findings are relevant to guide surgeons in optimizing their surgical procedures, such as conserving the menisci when possible, and rehabilitation protocols, by delaying full weight-bearing and return to sports in patients with anatomic and lesional risk factors. Level of evidence Cohort study, Level IV.

Level IV, systematic review of level III and IV studies.

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PurposeTo determine demographic, anatomic, and surgical factors associated with static and dynamic Anterior Tibial Translation (ATT) following ACL reconstruction. The hypothesis was that both static and dynamic ATT would be greater in knees with high tibial slope or that required meniscectomy. MethodsThe authors prospectively enrolled 280 consecutive patients that had primary ACL reconstruction using hamstring autografts at one center for which preoperative tear type, meniscal tears, and medial tibial slope were documented. A total of 137 were excluded due to concomitant extra‐articular tenodesis or surgical antecedents on either knee, and 18 were lost to follow‐up, leaving 125 that were evaluated at a minimum of 6 months including: static ATT on monopodal weight‐bearing radiographs, and dynamic ATT on differential stress radiographs using the Telos™ device. ResultsBoth postoperative static and dynamic ATT were strongly associated with preoperative static and dynamic ATT (respectively, β = 0.068 and β = 0.50, p < 0.001). Multivariable regression confirmed that postoperative static ATT increased with tibial slope (β = 0.24; CI 0.01–0.47; p = 0.042) and in knees that had partial medial meniscectomy (β = 2.05; CI 0.25–3.84; p = 0.025), while dynamic ATT decreased with age (β = − 0.11; CI − 0.16 to − 0.05; p < 0.001), and increased with tibial slope (β = 0.27; CI 0.04–0.49; p = 0.019) and in knees that had partial medial meniscectomy (β = 2.20; CI 0.35–4.05; p = 0.019). ConclusionBoth static and dynamic ATT following ACL reconstruction increased with tibial slope and in knees that had partial medial meniscectomy. These findings could help surgeons tailor their techniques and ‘à la carte’ rehabilitation protocols, by preserving the menisci and sometimes delaying full weight‐bearing and return to sport in patients at risk, and hence improve outcomes and prevent graft failures. Study designCohort study. Level of evidenceV.

Stability of the knee joint depends on soft tissues integrity and bony balance in the frontal and sagittal planes during gait. Although frontal plane imbalance is a well-known knee pathology, commonly treated by high tibial osteotomy, sagittal plane imbalance is less common, with fewer and more challenging surgical treatment options. The purpose of this review is to describe the biomechanical effects of sagittal knee imbalances and to outline the indications, techniques, and outcomes of sagittal knee osteotomies. The article details the reference axes and methods to measure posterior tibial slope (PTS), the principal indicator of sagittal imbalance, and its influence on anteroposterior tibial translations and rotational stability of the joint. The authors also outline the roles of the anterior and posterior cruciate ligaments in maintaining sagittal balance, with focus on the associations between PTS and ligament deficiencies, as well as posterolateral corner injuries. Different techniques and indications of tibial osteotomy in the sagittal plane, both above and below the anterior tibial tubercle, are compared in terms of technical difficulty, clinical benefits, and complication rates. The authors conclude on the importance of understanding sagittal knee imbalance, particularly in cases of ligament deficiencies, where the deformity can be the primary cause for lesions. Surgeons must identify the underlying deformities associated with sagittal imbalance, which can be recognized on weight-bearing X-rays and magnetic resonance imaging scans. Different techniques of sagittal osteotomies offer effective treatments for certain indications and should be considered in selected cases for unstable knees with ligament lesions.