Clinical effect of morphological changes in bone tunnels after anterior cruciate ligament reconstruction

Abhijeet Subhash; Nishant Kashyap; Indrajeet Kumar; Ritesh Runu

doi:10.4103/jodp.jodp_54_22

ORIGINAL ARTICLE

Year : 2023 | Volume : 6 | Issue : 1 | Page : 62-65

Clinical effect of morphological changes in bone tunnels after anterior cruciate ligament reconstruction

Abhijeet Subhash, Nishant Kashyap, Indrajeet Kumar, Ritesh Runu
Department of Orthopedics, IGIMS Patna, Bihar, India

Date of Submission	29-Jun-2022
Date of Decision	30-Jun-2022
Date of Acceptance	30-Jun-2022
Date of Web Publication	27-Dec-2022

Correspondence Address:
Ritesh Runu
Department of Orthopedics, IGIMS Patna-14, Bihar
India

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jodp.jodp_54_22

Abstract

Background: The effect of tunnel widening on clinical outcomes after anterior cruciate ligament (ACL) reconstruction has not been widely investigated. In this study, ACL reconstructions (ACL-Rs) were done by semitendinosus and gracilis tendon grafts and suspensory fixation on the femoral side. The aim was to study tunnel widening at the end of 1 year postoperative and correlate it with clinical outcomes. Materials and Methods: Fifty-five consecutive patients enrolled in the study underwent arthroscopic ACL-R. All were evaluated clinically using the Lysholm knee score and Tegner activity level preoperatively as well as during subsequent follow-up. Femoral and tibial tunnels were visualized with computed tomography scan which was performed at a mean duration of 1 year (range: 10–14 months). Results: The mean femoral tunnel diameter increased significantly (17.1%) from 8.03 ± 0.05 mm postoperatively to 9.04 ± 0.6 mm at 1 year; the tibial tunnel increased significantly (22.55%) from 9.04 ± 0.04 mm to 11.09 ± 0.8 mm at the same duration. No significant correlation could be established between tunnel widening and clinical evaluation scores. In both clinical evaluation scales, the overall improvement was noticed. Conclusions: Within a limit, neither femoral nor tibial tunnel widening affects the clinical outcome at 1 year of follow-up.

Keywords: Anterior cruciate ligament reconstruction, clinical outcome, tunnel widening

How to cite this article:
Subhash A, Kashyap N, Kumar I, Runu R. Clinical effect of morphological changes in bone tunnels after anterior cruciate ligament reconstruction. J Orthop Dis Traumatol 2023;6:62-5

How to cite this URL:
Subhash A, Kashyap N, Kumar I, Runu R. Clinical effect of morphological changes in bone tunnels after anterior cruciate ligament reconstruction. J Orthop Dis Traumatol [serial online] 2023 [cited 2023 Jan 30];6:62-5. Available from: https://jodt.org/text.asp?2023/6/1/62/365284

Introduction

Anterior cruciate ligament (ACL) reconstruction is among the most performed orthopedics knee surgery. Regardless of the technique used, tunnel enlargement has been reported among the related complications by authors.^{[1],[2],[3],[4],[5]} Mostly, it occurs within 6 months postoperatively and remains static till 1 year, but in some cases, it may continue up to 2 years^[6] and it has been reported with all types of grafts which may be autograft or allograft (bone-patellar bone graft or hamstring graft). Biomechanical factors that primarily contribute to tunnel widening are tunnel position along with types and rigidity of fixations (cortical or metaphyseal).^[7] The biological factors such as synovial fluid spillage at the bone and soft-tissue graft interface, poor bone quality, and disintegration of the bioabsorbable screw May cause tunnel widening.^[8] Previous studies on tunnel enlargement associate them with anterior knee laxity, graft failure,^[9],[10] and risk of staged revision surgery.^[11] On the contrary, many studies have proved that tunnel widening does not affect the clinical outcome following ACL reconstruction (ACL-R).^{[12],[13],[14],[15]} Computed tomography (CT) is shown to be a reliable imaging modality for the morphological evaluation of tunnels.^[6] As tunnel enlargement occurs in multiple directions, three-dimensional (3D) reconstruction of the CT image enables a more accurate evaluation. In addition, multi-planar analysis using 3D reconstructed CT images enables a more accurate evaluation because tunnel enlargement occurs in multiple directions.^[8]

Thus, the purpose of this study was a morphological evaluation of tunnels after 1 year of ACL-R using a hamstring tendon graft and to investigate any significant correlation between clinical scores and any such tunnel enlargement.

Materials and Methods

This was a prospective study conducted from February 2020 to May 2022 at a tertiary care hospital after institutional ethical clearance vide letter no. 747/IEC/2019/IGIMS. All patients with an ACL injury who underwent primary arthroscopic ACL-R using hamstring tendon autograft and were more than 18 years of age were included in the study after informed written consent. Patients with associated medial or lateral collateral ligament injury or those undergoing revision ACL-R and <18 years of age were excluded from the study. Diagnosis of ACL tear was made by clinical examination using Lachman and pivot shift tests and confirmed with MRI. Preoperative clinical evaluation of knee function and stability was performed using the Lysholm knee score and Tegner activity level.

Under spinal anesthesia, an arthroscopic examination was done to confirm ACL tear, and then, an ipsilateral autologous hamstring graft was harvested and prepared. The final thickness of the femoral and tibial ends was noted, and the femoral and tibial tunnels were made in accordance with it. The graft was fixed to the femoral tunnel by cortical fixation and to the tibial tunnel by interference screw and suture post (i.e., hybrid fixation). The diameters of the tibial and femoral tunnels after reaming were noted. Standard postoperative rehabilitation included postoperative limited mobilization in a hinged knee brace for 2 weeks.

At the end of a year after the operative intervention, clinical evaluation of knee function and stability was performed in a similar fashion as of preoperative. CT scan measurements of the femoral and tibial tunnels were done [Figure 1], [Figure 2], [Figure 3]. Transosseous tibial tunnel diameter was measured at four levels: axial section (T1) (T3) and sagittal section (T2) (T4) at plateau and midpoint. Femoral tunnel measurements were also done at four points: the axial (F1) and coronal (F2) sections in the middle of the tunnel and the axial sections at the notch (F3) and the end of the tunnel (F4).

Figure 1: Coronal section of femoral tunnel showing conical enlargement and its measurement

Click here to view

Figure 2: Axial section of femoral tunnel

Click here to view

Figure 3: Sagittal section of tibial tunnel and measurement

Click here to view

The statistical analysis was done using SPSS version 21.0 software SPSS (IBM, USA). The widening of the tibial and femoral tunnels at 12 months of follow-up was evaluated and correlated with different clinical scores. The Pearson correlation coefficient was used to identify the relationship between femoral and tibial tunnel widening and quantitative clinical parameters. P < 0.05 was considered statistically significant.

Results

This study included 55 patients with a mean age of 32 years (19–48 years), who underwent ACL-R surgery between February 2020 and May 2022, out of which 49 were males and 6 were females. There were 29 right and 26 left knees.

At 1 year, the typical appearance of the femoral tunnel widening was typical in a conical shape with a mean increase in the tunnel diameter of 1.41 + 0.4 mm (17.1%). In F1, the mean tunnel diameter was 8.95 + 0.04 which is an increase of 11.7%. In F2, the mean tunnel diameter was 9.66 + 0.05 mm which is an increase of 16.9%. In F3, the mean tunnel diameter was 11.15 + 0.04 mm which is an increase of 24.6%. In F4, the mean tunnel diameter was 9.76 + 0.07 mm which is an increase of 15.2% [Table 1].

Table 1: Increment in femoral tunnel diameter (mm)

Click here to view

The 3D appearance of the tibial tunnel is cylindrical, with a mean increase in tunnel diameter of 2.05 + 0.03 (22.74%). In T1, the mean tunnel diameter was 11.22 + 0.04 which is an increase of 18.4%. In T2, the mean tunnel diameter was 12.39 + 0.05 mm which is an increase of 21.6%. In T3, the mean tunnel diameter was 12.56 + 0.04 mm which is an increase of 24.8%. In T4, the mean tunnel diameter was 13.43 + 0.07 mm which is an increase of 25.4% [Table 2].

Table 2: Increment in tibial tunnel diameter (mm)

Click here to view

The mean Lysholm score increased from 55.7 ± 16 (52–77) points preoperatively to 94.8 ± 18 points (89–100) postoperatively. The mean Tegner activity score increased from 2.5 ± 0.96 points preoperatively to 5.4 ± 1.05 postoperatively [Table 3].

Table 3: Improvement in clinical scores

Click here to view

There was no re-trauma or iterative rupture at the last follow-up. Radiographic findings did not demonstrate any tunnel malposition, and CT scan analysis did not show a greater tunnel widening compared with other studies. There was no significant correlation between tunnel enlargement and the clinical outcome.

Discussion

The main purpose of the present retrospective clinical study was to evaluate the impact of femoral and tibial tunnel widening after ACL-R on clinical outcomes after a 1-year follow-up.

Regardless of the technique used bone tunnels created for graft placement in ACL-R enlarge with time. Jansson et al.^[16] report an average femoral and tibial tunnel enlargement on AP-view of plain X-ray of 33% and 23%, respectively, while Fules et al.^[17] reports an average tibial tunnel enlargement of 33% on magnetic resonance imaging, after ACL-R using a hamstring graft. The present study demonstrates a 17.9% increment in femoral tunnel diameter and a 22.6% increment in tibial tunnel diameter following ACL-R with hamstring grafts.

Some studies have correlated the relationship between tunnel widening and rehabilitation. Murty et al.^[18] showed that immobilization for 2 weeks was associated with increased tunnel enlargement. L'Insalata et al.^[19] show that less aggressive rehabilitation may reduce the micromotion of the graft in the tibial and femoral tunnels, thus reducing the “synovial bathing effect” and the nonspecific inflammatory response. In this study, a less aggressive rehabilitation process resulted in an acceptable rate of tunnel enlargement.

In a review article, Höher et al.^[20] discuss theoretical concepts surrounding the etiology as well as possible measures for preventing bone tunnel enlargement. They conclude that prevention of bone tunnel enlargement may be achieved by a more anatomical initial graft fixation. Moreover, this is also backed by the findings of Schulte et al.,^[21] who found that tunnel expansion was greater in the lateral radiograph for bone-patellar tendon-bone grafts fixed more distally in the tibial tunnel. In our study, we created anatomic tunnel hence -- in comparison with other studies with nonanatomic tunnel creation, the percentage of tunnel widening is considerably less.

The limitations of our study was short term follow up of 1 year. CT scan measurement need to be evaluated for interobserver variability.

Conclusions

The present study demonstrated that femoral and tibial tunnel enlargement is a regular phenomenon after anatomic ACL-R using hamstring tendon autografts. The tunnel enlargement does not affect the clinical outcome during the 1-year period after anatomic ACL reconstruction.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1.	Aglietti P, Zaccherotti G, Simeone AJ, Buzzi R. Anatomic versus non-anatomic tibial fixation in anterior cruciate ligament reconstruction with bone-patellar tendon-bone graft. Knee Surg Sports Traumatol Arthrosc 1998;6 Suppl 1:S43-8.
2.	Fahey M, Indelicato PA. Bone tunnel enlargement after anterior cruciate ligament replacement. Am J Sports Med 1994;22:410-4.
3.	Hersekli MA, Akpinar S, Ozalay M, Ozkoc G, Cesur N, Uysal M, et al. Tunnel enlargement after arthroscopic anterior cruciate ligament reconstruction: Comparison of bone-patellar tendon-bone and hamstring autografts. Adv Ther 2004;21:123-31.
4.	Otsuka H, Ishibashi Y, Tsuda E, Sasaki K, Toh S. Comparison of three techniques of anterior cruciate ligament reconstruction with bone-patellar tendon-bone graft. Differences in anterior tibial translation and tunnel enlargement with each technique. Am J Sports Med 2003;31:282-8.
5.	Zijl JA, Kleipool AE, Willems WJ. Comparison of tibial tunnel enlargement after anterior cruciate ligament reconstruction using patellar tendon autograft or allograft. Am J Sports Med 2000;28:547-51.
6.	Marchant MH Jr., Willimon SC, Vinson E, Pietrobon R, Garrett WE, Higgins LD. Comparison of plain radiography, computed tomography, and magnetic resonance imaging in the evaluation of bone tunnel widening after anterior cruciate ligament reconstruction. Knee Surg Sports Traumatol Arthrosc 2010;18:1059-64.
7.	Choi NH, Oh JS, Jung SH, Victoroff BN. Correlation between endobutton loop length and tunnel widening after hamstring anterior cruciate ligament reconstruction. Am J Sports Med 2013;41:101-6.
8.	Basson B, Philippot R, Neri T, Meucci JF, Boyer B, Farizon F. The effect of femoral tunnel widening on one-year clinical outcome after anterior cruciate ligament reconstruction using ZipLoop^® technology for fixation in the cortical bone of the femur. Knee 2016;23:233-6.
9.	Siebold R, Kiss ZS, Morris HG. Effect of compaction drilling during ACL reconstruction with hamstrings on postoperative tunnel widening. Arch Orthop Trauma Surg 2008;128:461-8.
10.	Kawaguchi Y, Kondo E, Kitamura N, Kai S, Inoue M, Yasuda K. Comparisons of femoral tunnel enlargement in 169 patients between single-bundle and anatomic double-bundle anterior cruciate ligament reconstructions with hamstring tendon grafts. Knee Surg Sports Traumatol Arthrosc 2011;19:1249-57.
11.	Peyrache MD, Djian P, Christel P, Witvoet J. Tibial tunnel enlargement after anterior cruciate ligament reconstruction by autogenous bone-patellar tendon-bone graft. Knee Surg Sports Traumatol Arthrosc 1996;4:2-8.
12.	Webster KE, Feller JA, Hameister KA. Bone tunnel enlargement following anterior cruciate ligament reconstruction: A randomised comparison of hamstring and patellar tendon grafts with 2-year follow-up. Knee Surg Sports Traumatol Arthrosc 2001;9:86-91.
13.	Buelow JU, Siebold R, Ellermann A. A prospective evaluation of tunnel enlargement in anterior cruciate ligament reconstruction with hamstrings: Extracortical versus anatomical fixation. Knee Surg Sports Traumatol Arthrosc 2002;10:80-5.
14.	Ito MM, Tanaka S. Evaluation of tibial bone-tunnel changes with X-ray and computed tomography after ACL reconstruction using a bone-patella tendon-bone autograft. Int Orthop 2006;30:99-103.
15.	Fink C, Zapp M, Benedetto KP, Hackl W, Hoser C, Rieger M. Tibial tunnel enlargement following anterior cruciate ligament reconstruction with patellar tendon autograft. Arthroscopy 2001;17:138-43.
16.	Jansson KA, Harilainen A, Sandelin J, Karjalainen PT, Aronen HJ, Tallroth K. Bone tunnel enlargement after anterior cruciate ligament reconstruction with the hamstring autograft and endobutton fixation technique. A clinical, radiographic and magnetic resonance imaging study with 2 years follow-up. Knee Surg Sports Traumatol Arthrosc 1999;7:290-5.
17.	Fules PJ, Madhav RT, Goddard RK, Newman-Sanders A, Mowbray MA. Evaluation of tibial bone tunnel enlargement using MRI scan cross-sectional area measurement after autologous hamstring tendon ACL replacement. Knee 2003;10:87-91.
18.	Murty AN, el Zebdeh MY, Ireland J. Tibial tunnel enlargement following anterior cruciate reconstruction: Does post-operative immobilisation make a difference? Knee 2001;8:39-43.
19.	L'Insalata JC, Klatt B, Fu FH, Harner CD. Tunnel expansion following anterior cruciate ligament reconstruction: A comparison of hamstring and patellar tendon autografts. Knee Surg Sports Traumatol Arthrosc 1997;5:234-8.
20.	Höher J, Möller HD, Fu FH. Bone tunnel enlargement after anterior cruciate ligament reconstruction: Fact or fiction? Knee Surg Sports Traumatol Arthrosc 1998;6:231-40.
21.	Schulte K, Majewski M, Irrgang JJ, Fu FH, Harner CD. Radiographic tunnel changes following arthroscopic reconstruction: Autograft versus allograft. Arthroscopy 1995;11:372-3.