Comparison between functional outcomes of aperture fixation and suspensory fixation on the tibial side in arthroscopic anterior cruciate ligament reconstruction patients: A randomized control trial

INTRODUCTION

The anterior cruciate ligament (ACL) is fundamental for maintaining knee joint stability, especially in activities involving pivoting and jumping.^[1] ACL reconstruction (ACLR) is the gold standard treatment for restoring sagittal and rotational knee stability after an ACL tear, aiming to prevent further meniscal or chondral damage and facilitate return to pre-injury activity levels.^[2,3] This is particularly important for young and athletic populations who are most vulnerable to ACL injuries.^[4] Anatomically accurate reconstruction techniques have evolved to recreate native ACL biomechanics and reduce the risk of early osteoarthritis, which was inadequately addressed by earlier non-anatomic approaches.^[5]

Among these techniques, graft choice and fixation strategy significantly influence surgical success. While hamstring autografts remain a popular option due to their strength and lower donor site morbidity, achieving secure tibial fixation is critical, especially since tibial bone is less dense than femoral bone, which makes it more susceptible to early post-operative complications.^[6,7] The two predominant tibial fixation techniques are aperture fixation, typically using interference screws, and suspensory fixation devices such as adjustable-loop cortical buttons.^[8,9]

Aperture fixation allows close bone-to-graft contact and biological integration, but risks graft laceration during screw insertion and may limit healing due to reduced space for tendon-to-bone integration.^[9] In contrast, suspensory fixation avoids many of these risks and has gained popularity for its technical ease and mechanical reliability.^[10] Furthermore, the all-inside technique employing suspensory fixation has shown favorable short-term outcomes, including reduced postoperative pain and improved joint stability.^[11,12] Despite these advancements, the literature remains divided on whether one fixation method offers superior functional outcomes. Clinical decision-making often depends on surgeon preference and individual patient anatomy. Therefore, this randomized controlled trial was conducted to directly compare the functional outcomes of aperture fixation versus suspensory fixation on the tibial side in patients undergoing arthroscopic ACLR and was aimed at providing clearer evidence to guide clinical practice.

MATERIALS AND METHODS

RESULTS

A total of 104 patients were included in the study, with 52 patients in each fixation group (BIOSCREW and T-BUTTON). The mean age of patients was comparable between the BIOSCREW group (31.69 ± 9.99 years) and the T-BUTTON group (30.48 ± 9.79 years). Gender distribution was also similar, with a higher proportion of males in both groups: 76.9% in BIOSCREW and 82.7% in T-BUTTON [Figure 1]. In the BIOSCREW group, 44.2% were office employees, followed by 34.6% students and 9.6% housewives. In the T-BUTTON group, office employees and students each constituted 36.5%, followed by 7.7% housewives [Table 1].

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Figure 1:

Gender distribution of the patients.

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Preoperatively, the majority of patients from both groups demonstrated a positive Grade 2 result on the anterior drawer test, with 61.5% in the BIOSCREW group and 59.6% in the T-BUTTON group. Positive Grade 1 results were observed in 23.1% (BIOSCREW) and 30.8% (T-BUTTON), while Grade 3 was less frequent, seen in 15.4% and 9.6% of BIOSCREW and T-BUTTON patients, respectively [Table 1 and Figure 2].

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Figure 2:

Distribution of patients according to Lachman test.

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Pre-operative pain scores were similar between groups, with BIOSCREW at 4.02 and T-BUTTON at 4.15. Immediately after surgery, the T-BUTTON group reported slightly higher pain levels (5.21) compared to BIOSCREW (4.85). However, by the 3^rd post-operative week, pain scores had decreased to 2.48 in both groups. At 6 weeks, BIOSCREW patients reported marginally lower pain scores (1.94 ± 2.02) than the T-BUTTON group (2.02). Differences in VAS scores across time points between the two groups were not statistically significant [Table 2].

Pre-operative IKDC scores were comparable between groups, with BIOSCREW scoring 49.73 and T-BUTTON 48.89. Immediately postoperatively, T-BUTTON patients had slightly higher scores (47.09) compared to BIOSCREW (43.93). This trend continued at 3 weeks (53.84 vs. 52.96), though the differences were not statistically significant. At 6 weeks, scores were nearly identical (60.27 for BIOSCREW and 59.63 for T-BUTTON). By the 3^rd month, BIOSCREW patients exhibited slightly higher scores (69.21) compared to T-BUTTON (65.50), suggesting a marginally better functional recovery [Table 3].

DISCUSSION

This randomized controlled trial aimed to directly compare the functional outcomes and postoperative pain trajectories associated with two commonly used tibial fixation techniques, aperture (BIOSCREW) and suspensory (T-BUTTON) fixation, in patients who underwent arthroscopic ACLR. The findings suggested that both techniques provided comparable clinical outcomes in terms of pain reduction, functional recovery, and post-operative stability.

The study population showed a male predominance in both fixation groups (BIOSCREW: 76.9%, T-BUTTON: 82.7%), consistent with well-documented trends indicating higher ACL injury rates in males, likely due to greater participation in high-risk sports and physically demanding activities. The small, non-significant difference in sex distribution between groups allowed for an unbiased comparison of functional outcomes. In line with the present study, Crum et al. and Browning et al. also reported a male-dominant pattern,^[13,14] supporting the representativeness of the sample and minimizing sex-related confounding factors.

Preoperatively, both BIOSCREW and T-BUTTON groups in the present study showed a high prevalence of positive anterior drawer test results, predominantly grade 2, indicating significant ACL laxity consistent with typical ACL-deficient knees. This aligned with existing literature where similar pre-operative instability grades had been reported and validated through objective assessments such as KT-1000 arthrometry.^[15] The comparable distribution of instability between groups strengthened the validity of postoperative outcome comparisons by minimizing baseline bias. These findings corresponded with prior studies^[13,14] that emphasized the importance of addressing such instability to justify surgical reconstruction.

Similarly, the Lachman test, recognized for its sensitivity in detecting ACL injury, was positive in all patients preoperatively and negative postoperatively, reflecting successful restoration of knee stability. This mirrored results from several studies^[16,17] where a negative postoperative Lachman test served as a reliable clinical indicator of effective ACL repair and stable knee kinematics. Together, these clinical assessments provided crucial baseline and outcome measures, underscoring the efficacy of both fixation techniques in restoring ligament function and knee stability. The observed post-operative pain trajectories between BIOSCREW and T-BUTTON fixation techniques were also similar, consistent with prior studies evaluating pain outcomes after ACLR. Several studies^[18,19] reported no significant differences in early or late post-operative pain levels between aperture and suspensory fixation methods, supporting the notion that fixation technique did not substantially influence patient-reported pain. The gradual reduction in pain over time observed in this study aligned with the typical post-operative recovery pattern described by Johnson et al.,^[20] where initial surgical discomfort progressively subsided during healing. Although some reports suggested slightly increased early post-operative pain with suspensory fixation due to soft tissue irritation, these differences often lacked statistical significance and tended to resolve with time, paralleling the current results.^[20] Overall, the data reinforced that both fixation strategies were effective in managing post-operative pain and provided comparable comfort during recovery, emphasizing that other factors, such as surgical technique and rehabilitation, might have played more critical roles in influencing pain outcomes than the choice of tibial fixation alone.^[21]

The observed comparable functional recovery between BIOSCREW and T-BUTTON fixation techniques was also consistent with previous research in ACLR. A study by Lubowitz et al.^[18] reported no significant differences in IKDC scores between aperture and suspensory fixation at 6 months and 1 year, indicating both methods effectively restored knee function. Similarly, a study by Johnson et al.^[20] observed parallel improvements in functional outcomes with these fixation types, suggesting that the choice of tibial fixation might not significantly affect short- to mid-term recovery. Although a study by Gill et al.^[22] noted slightly better early post-operative stability with aperture fixation, these differences tended to diminish over time, aligning with the observed convergence of IKDC scores by 3 months. The gradual improvement in this cohort also mirrored typical rehabilitation patterns reported in the literature,^[23,24] emphasizing that comprehensive post-operative care was crucial regardless of the fixation technique used.

CONCLUSION

This study indicates that both aperture (BIOSCREW) and suspensory (T-BUTTON) tibial fixation techniques yield comparable outcomes in terms of pain management and functional recovery following arthroscopic ACLR. The lack of significant differences in VAS and IKDC scores between the two groups suggests that either fixation method can be effectively utilized to restore knee function and control post-operative pain.