• Hip & Knee Conditions
• Sports Medicine
• Orthopaedic Procedures Clinical Trials

• Hip & Knee Conditions
• Sports Medicine
• Orthopaedic Procedures
• Orthopaedics Clinical Trials
• Orthopaedics

Joshua Christensen, MD, Mayo Clinic, Rochester, Minnesota, USA, presented data from a study that was conducted to determine the relationship between lateral tibial posterior slope (LTPS) and the probability of early graft failure in patients who have undergone anterior cruciate ligament (ACL) reconstruction. The results showed that regardless of graft type, increased LTPS is associated with an increased risk for early ACL graft failure, especially in women.

A growing number of reports suggest that LTPS is a risk factor for ACL injury [Wordeman SC et al. Am J Sports Med 2012]. However, the effect of LTPS on ACL graft failure is unknown. With this in mind, Dr. Christensen and colleagues conducted a case-control study in skeletally mature patients who experienced early graft failure following primary ACL reconstruction and underwent surgical revision between 1998 and 2009.

Exclusion criteria included clinical follow-up of < 4 years, graft failure occurring > 2 years from the time of the primary surgery, skeletal immaturity, deep infection, lack of availability of preoperative magnetic resonance imaging (MRI), and a history of previous proximal tibial trauma. Among 58 cases that were originally evaluated for inclusion, 35 cases (n = 21 for men) remained in which patients experienced early (within 2 years) failure of primary ACL reconstruction. These were matched to 35 control cases (n = 21 for men) involving patients who had undergone ACL reconstruction with a minimum of 4 years of clinical follow-up and no evidence of graft failure. Patients were matched by age, gender, date of primary surgery, and graft type (n = 14 for bone—patellar tendon—bone, n = 13 for hamstring autograft, and n = 8 for allograft in each group). Lateral tibial slope was determined on MRI imaging in blinded fashion.

In the graft failure group, all 35 cases failed within 2 years of primary ACL reconstruction, with a mean time to failure of 1 year (range, 0.6 to 1.4 years). In the matched control group, mean follow-up was 6.9 years (range, 4.0 to 13.9 years). Overall in the early ACL failure group, mean lateral tibial slope was significantly higher than that the control group (8.4° vs 6.5°; p = .012; odds ratio [OR], 1.6; 95% CI, 1.1 to 2.2), and the ORs increased to 2.4 (95% CI, 1.2 to 5.0) and 3.8 (95% CI, 1.3 to 11.3) with 4° and 6° increases in tibial slope, respectively.

This effect was also particularly pronounced in women, in which group mean lateral tibial slope was also significantly higher than in the control group (9.1° vs 5.9°; p = .007; OR, 2.2; 95% CI, 1.0 to 5.2). The ORs increased to 4.9 (95% CI, .9 to 26.7) and 10.9 (95% CI, .9 to 26.7) with 4° and 6° increases in tibial slope, respectively.

There was no significant association between graft type and primary ACL reconstruction failure.

Limitations of this study included its retrospective nature, as well as the need for dedicated software and the multiple steps required for measurement. However, because the data show that increased LTPS is associated with an increased risk for early ACL graft failure, Dr. Christensen concluded that orthopedic surgeons should consider measuring LTPS as part of their preoperative assessment of patients with ACL injury.

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