Placement of femoral tunnel between the AM and PL bundles using a transtibial technique in single-bundle ACL reconstruction

Tunnel enlargement after anterior cruciate ligament (ACL) reconstruction may compromise revision surgery. The cause of this tunnel enlargement is not yet fully understood, but it is thought to be multifactorial, with biomechanical and biological factors playing a role. Tunnel enlargement has been described particularly in patients who underwent ACL reconstruction with hamstring tendons with extracortical fixation devices. The purpose of our study was to evaluate prospectively with magnetic resonance imaging (MRI) the changes in femoral tunnel diameter following arthroscopic anatomic ACL reconstruction with hamstring tendons. At 3-month post-op, all tunnels had enlarged compared to the diameter of the drill and most tunnels enlarged more in the midsection than at the aperture. In the posterolateral tunnels, the entrance increased 16% in diameter and the middle of the tunnel increased 30% in diameter. In the anteromedial femoral tunnels, the tunnels enlarged 14% at the aperture and 35% in the midsection. All femoral tunnels enlarged and most of them enlarged in a fusiform manner. The biological factors explain better our findings than the mechanical theory, although mechanical factors may play a role and the cortical bone at the entrance of the tunnel may modify the way tunnels respond to mechanical stress.     

Femoral bone tunnel placement using the transtibial tunnel or the anteromedial portal in ACL reconstruction: a radiographic evaluation

Correct placement of the tibial and femoral bone tunnel is prerequisite to a successful anterior cruciate ligament (ACL) reconstruction. This study compares the resulting radiographic femoral bone tunnel position of two commonly used techniques for arthroscopically assisted drilling of the femoral bone tunnel: the transtibial approach or drilling through the anteromedial arthroscopy portal. The resulting bone tunnel position was assessed in postoperative knee radiographs of 70 patients after ACL reconstruction. Three independent observers identified the femoral bone tunnel and determined its position in the lateral and A–P view. Differences in femoral tunnel position between transtibial and anteromedial drilling were evaluated. In the sagittal plane, significantly more femoral bone tunnels were positioned close to the reference value using an anteromedial drilling technique (86%) when compared to transtibial drilling (57%). Drilling through the transtibial tunnel resulted in a significantly more anterior position of the femoral tunnel. In the frontal plane, femoral bone tunnels which were placed through the anteromedial arthroscopy portal displayed a significantly greater angulation towards the lateral condylar cortex (50.92°) when compared to transtibial drilling (58.82°). In conclusion, drilling the femoral tunnel through the anteromedial arthroscopy portal results in a radiographic femoral bone tunnel position which is suggested to allow stabilization of both anterior tibial translation and rotational instability when using a single bundle reconstruction technique. Further studies may evaluate if there are any clinical advantages using the anteromedial portal technique.     

The effect of remnant preservation on tibial tunnel enlargement in ACL reconstruction with hamstring autograft: a prospective randomized controlled trial

Purpose

To investigate the effect of remnant preservation on tibial tunnel enlargement in a single-bundle anterior cruciate ligament (ACL) reconstruction with a hamstring autograft.

Methods

From 2006 to 2009, a total of 62 patients who underwent single-bundle ACL reconstruction with a quadrupled hamstring tendon autograft were enrolled in this study. The patients were randomly divided into two groups: the preserving-remnant group and the removing-remnant group. Plain radiographs were taken at 1 week, and 3, 6, and 24 months postoperatively, and tibial tunnel enlargement was evaluated. The postoperative clinical assessment included the Lysholm rating scale and KT-1000 measurement.

Results

In total, 27 patients in the preserving-remnant group and 24 patients in the removing-remnant group were followed up and the median follow-up was 24.5 months (range 24–27 months). Tibial tunnel enlargement occurred within 6 months postoperatively. Positive enlargement was observed in 8 patients (29.6 %) in the preserving-remnant group and 14 patients (58.3 %) in the removing-remnant group (P = 0.0388). The percentage of tibial tunnel enlargement was 25.7 ± 6.7 and 34.0 ± 8.9 % in the preserving- and removing-remnant groups, respectively (P = 0.0004). In the preserving-remnant group, the average Lysholm score increased from 60.3 ± 5.3 (51–69) to 93.0 ± 3.5 (88–100), and the side-to-side difference of the KT-1000 changed from 6.3 ± 0.9 (5.1–8.0) to 1.4 ± 0.6 (0.5–2.4) mm. In the removing-remnant group, the average Lysholm score increased from 58.7 ± 6.5 (48–71) to 91.1 ± 3.9 (85–100), and the side-to-side difference of the KT-1000 changed from 6.5 ± 0.8 (5.4–8.2) to 1.7 ± 0.6 (0.6–2.8) mm.

Conclusions

It is confirmed that remnant preservation in ACL reconstruction can resist tibial tunnel enlargement but that this technique does not affect the short-term clinical outcome of ACL reconstruction.

Level of evidence

I.     

Isokinetic flexion strength recovery after ACL reconstruction: a comparison between all inside graft-link technique and full tibial tunnel technique

Introduction: Recently, a new minimally invasive single bundle technique for anatomic ACL reconstruction has been described, called the ‘All-Inside graft-link technique’. One of the advantages of this procedure is the reduced morbidity at the donor site as the graft choice is the quadrupled semitendinosus, thus sparing the gracilis tendon. The aim of this study was to evaluate isokinetic flexion strength recovery in patients who underwent a gracilis sparing technique compared to those with a full-tibial tunnel technique using a doubled gracilis and semitendinosus tendons (DGST) graft.

Methods: Patients were divided into two groups: Group A (22 patients) who underwent ACL reconstruction performed with an All-Inside graft-link technique; Group B (22 patients) who underwent ACL reconstruction with an Out-In technique and DGST graft. At a mean follow-up of 13 months, quadriceps and hamstring isokinetic peak torque deficits were recorded.

Results: In group A, the mean side to side peak torque flexion difference between the operated and non-operated limbs was ?3% and the mean torque at 30° was ?7.5% at high angular velocity (180°/sec); the mean peak flexion torque was 7.2% and the mean torque at 30° was 3.1% at low angular velocity (60°/sec).

In group B, the mean side to side peak flexion torque was ?3.5% and the mean torque at 30° was ?7.6% at high angular velocity (180°/sec); the mean peak flexion torque was ?7.2% and the mean torque at 30° was ?11% at low angular velocity (60°/sec).

A statistically significant difference was found between the two groups at lower angular velocity both for the mean peak flexion torque and the mean torque at 30° (p = 0.009), with better results in the study group.

Discussion/conclusion: Gracilis sparing technique is a minimally invasive technique for ACL reconstruction and yielded a significantly better flexion strength recovery at lower angular velocity compared to a full tibial tunnel technique with DGST for ACL reconstruction.     

Long-term results after reconstruction of the ACL with hamstrings autograft and transtibial femoral drilling

Purpose

To evaluate the long-term clinical, patient-reported and radiological outcome of patients reconstructed for anterior cruciate ligament (ACL) insufficiency. We wanted to examine the relationship between clinical findings and patient-reported scores.

Methods

The 96 first successive patients that underwent ACL reconstruction using transtibial technique, hamstrings autograft and tunnel placement ad modum Howell were evaluated 10 years post-operatively. Subjective outcomes were Lysholm score, IKDC 2000 subjective score and Tegner activity scale. The clinical examination included evaluation of rotational and sagittal laxity. Evaluation of osteoarthritis was done radiologically.

Results

Eighty-three patients (86 %) were available for follow-up at mean 10.2 years post-operatively. Three patients had revision ACL surgery prior to the 10-year evaluation. The mean Lysholm score, subjective IKDC 2000 score and Tegner activity scale were 89 (SD 13), 83 (SD 15) and 5 (range, 3–9), respectively. Six patients (8 %) had moderate or severe osteoarthritis. Eighty-six per cent of patients had normal or near-normal anterior–posterior ACL laxity. Twenty per cent of patients had positive pivot shift and 42 % had a pivot glide. The former group had a significant lower Lysholm score compared to the rest of the patients.

Conclusions

Although the mean Lysholm score was classified as good (89) at the 10-year follow-up, a positive pivot shift was found in 20 % of these patients. Compared to patients with normal rotational laxity or pivot glide, this patient group reported significant lower subjective satisfaction at the long-term follow-up.

Level of evidence

Case series, Level IV.     

ACL reconstruction with double-bundle technique: a review of clinical results

Anatomical and biomechanical studies have shown that the anterior cruciate ligament (ACL) primarily consists of 2 distinct bundles, the anteromedial (AM) and posterolateral (PL), which act separately during the knee's range of motion. Conventional ACL reconstruction techniques have focused on restoration of the AM bundle only, while giving limited attention to the PL bundle. The outcomes of these single-bundle techniques have been relatively good in ACL reconstruction. In recent years, many authors have developed double-bundle ACL reconstruction techniques to better replicate ACL anatomy and its 2 bundles. The purpose of this article is to analyze the clinical results of the double-bundle ACL reconstruction according to the current literature. The review focuses primarily on randomized controlled trials. According to the 14 randomized controlled trials published in the literature and included in this review, 4 (29%) trials did not find any significant differences in the results between double-bundle and single-bundle ACL reconstruction. Ten (71%) trials reported significantly better results with double-bundle technique than with single-bundle technique, of which 7 (50%) reported better rotational stability, 6 (43%) reported better anterior stability, 3 (21%) reported better objective knee scores, 3 (21%) reported better subjective knee scores, 2 (14%) reported fewer graft failures, and 1 (7%) reported less degenerative changes of the knee. In addition, none of the trials found the single-bundle technique to have better results in any of these evaluations when compared with the double-bundle technique. However, 13 (93%) of the 14 trials had only a short-term follow-up (1-3 years), and only 1 (7%) trial conducted long-term follow-up (8-10 years). Therefore, only through long-term follow-up studies will we be able to determine whether the double-bundle reconstruction is really better than the single-bundle technique.     

Calcium phosphate-hybridized tendon grafts reduce femoral bone tunnel enlargement in anatomic single-bundle ACL reconstruction

Purpose

This study aimed to clarify the effect of calcium phosphate (CaP)-hybridized tendon grafting versus unhybridized tendon grafting on the morphological changes to the bone tunnels at the aperture 1 year after anatomic single-bundle anterior cruciate ligament (ACL) reconstruction.

Methods

Seventy-three patients were randomized to undergo the CaP (n = 37) or the conventional method (n = 36). All patients underwent computed tomography (CT) evaluation 1 week and 1 year post-operatively. The femoral and tibial tunnels at the aperture were evaluated on reconstructed 3D CT images. Changes in the cross-sectional area (CSA) and diameters of the femur and the tibia, and the translation rate of the tunnel walls and the morphological changes of both tunnels were assessed.

Results

There was a significant reduction in the increase in the CSA and the anterior–posterior and proximal–distal tunnel diameters on the femoral side in the CaP group as compared with the conventional group. On the femoral side, the translation rate of the posterior wall was significantly larger in the CaP group than in the conventional group, whereas the translation rate of the distal wall was significantly smaller in the CaP group than in the conventional group.

Conclusions

As compared with the conventional method, the CaP-hybridized tendon graft reduced bone tunnel enlargement on the femoral side 1 year after anatomic single-bundle ACL reconstruction due to an anterior shift of the posterior wall and reduced distal shift in the femoral bone tunnel. Clinically, the CaP-hybridized tendon grafts can prevent femoral bone tunnel enlargement in anatomic single-bundle ACL reconstruction.

Level of evidence

I.

     

No bone tunnel enlargement in patients with open growth plates after transphyseal ACL reconstruction

Bone tunnel enlargement after ACL reconstruction has been described extensively in adults. However, little is known about this phenomenon in patients with open growth plates. Thus, the goals of the current study were to evaluate changes in bone tunnel size in patients with open growth plates after transphyseal ACL reconstruction with suspensory fixation and to correlate tunnel size with clinical outcome after medium-term follow-up. Fourteen patients with open growth plates were included that underwent primary transphyseal ACL reconstruction using hamstrings autografts and suspensory fixation. Mean follow-up time was 7 years. At the time of follow-up, MRIs of the operated knee were performed, and outcome was assessed using KOS-ADLS, Lysholm score, IKDC Subjective Knee Form score, Knee Examination Form score, and KT-1000 measurements. On MRI, the cross-sectional area of the bone tunnels was assessed using special axial cuts perpendicular to the axes of the tunnels. Two orthopaedic surgeons and two radiologists analysed the MRIs. Change in bone tunnel size from surgery to follow-up was calculated. No significant changes in bone tunnel size from surgery to follow-up were found. Regarding outcome measures, KOS-ADLS averaged 95%, Lysholm Score averaged 96 points, IKDC Subjective Knee Form averaged 95%, IKDC Knee Examination Form scores were 8A, 5B, 1C, and KT-1000 measurements averaged 1.8 ± 1.4 mm. No significant correlations were found between tunnel size at follow-up and outcome measures. Based on our study, bone tunnel enlargement does not occur in patients who have open growth plates and undergo ACL reconstruction using suspensory fixation.     

Comparison of tibial tunnel enlargement after anterior cruciate ligament reconstruction using patellar tendon autograft or allograft

This retrospective study was designed to compare tibial tunnel enlargement in patients with autograft or allograft anterior cruciate ligament reconstructions. The changes were related to position of the tibial tunnel and clinical outcome. Twenty-six patients with autograft reconstructions and 41 with allograft reconstructions were studied at a mean follow-up of 59 months (range, 41 to 84) after surgery. The average tunnel enlargement on the anteroposterior view was 2.2 mm (SD, 2.5) for autografts and 2.8 mm (SD, 2.1) for allografts. On the lateral view, the tunnel enlargement was 2.6 mm (SD, 2.4) and 3.4 mm (SD, 2.6) for autografts and allografts, respectively. No significant differences were found between the autograft and allograft groups. A trend was found in the correlation between the position of the tibial tunnel and the tunnel enlargement: more anteriorly placed tunnels had more enlargement. The changes in tunnel diameter did not relate to knee functional score or laxity. There was a significant correlation between malposition of the tibial tunnel and poor clinical scores. A significant negative correlation was found between postoperative follow-up time and tunnel enlargement in both groups. We conclude that placement of the tibial tunnel is a determining factor in tibial tunnel enlargement and clinical knee scores after anterior cruciate ligament replacement with an autograft or allograft. Tunnel enlargement tends to be less at a longer postoperative follow-up.     

Single-bundle transtibial posterior cruciate ligament reconstruction using a bioabsorbable cross-pin tibial back side fixation

Purpose

The purpose of this study was to examine a developed surgical technique by performing a mid-term evaluation of clinical and stability results and complications.

Methods

Thirty patients who underwent transtibial posterior cruciate ligament (PCL) reconstruction using a bioabsorbable cross-pin tibial back side fixation method were enrolled in this prospective study. Lysholm and International Knee Documentation Committee (IKDC) knee scales were used to evaluate clinical outcomes. Stability was evaluated using a Telos device with a 150 N force at 90 degrees of knee flexion. Follow-up magnetic resonance imaging (MRI) was also performed in 20 (66.7%) patients, and complications were evaluated. Those with complication by MRI were assigned to an abnormal MRI group.

Results

The follow-up period was 47 (range, 25–62) months. On comparing preoperative and final follow-up clinical results, Lysholm and IKDC knee scale scores were found to have improved significantly (P < 0.001). The mean side-to-side difference in posterior translation measured using a Telos device was 13.4 ± 3.1 mm (range 10–20 mm) preoperatively and 3.2 ± 1.5 mm (range 1–7 mm) at last follow-up, which represented a significant improvement in stability (P < 0.001). Five patients showed cyst formation in the tibial tunnel and two patients showed a significant signal increase at the anterior portion of the tibial tunnel, which was believed to indicate a pro-cystic status. The normal and abnormal MRI groups had similar Lysholm and IKDC knee scale scores and stress radiographs (P > 0.05).

Conclusions

Single-bundle transtibial PCL reconstruction using a bioabsorbable cross-pin tibial back side fixation was found to produce satisfactory clinical and stability results. However, despite these satisfactory results, a potential complication of tibial cyst formation was observed.

Level of evidence

Case series, Level IV.     

The effect of accelerated,brace free,rehabilitation on bone tunnel enlargement after ACL reconstruction using hamstring tendons: a CT study

The mechanism of bone tunnel enlargement following anterior cruciate ligament (ACL) reconstruction is not yet clearly understood. Many authors hypothesized that aggressive rehabilitation protocols may be a potential factor for bone tunnel enlargement, especially in reconstructions performed with hamstrings autograft. The purpose of this study was to evaluate the effect of a brace free rehabilitation on the tunnel enlargement after ACL reconstruction using doubled semitendinosus and gracilis tendons (DGST): our hypothesis was that early post-operative knee motion increase the diameters of the tibial and femoral bone tunnels. Forty-five consecutive patients undergoing ACL reconstruction for chronic ACL deficiency were selected. All patients were operated by the same surgeon using autologous DGST and the same fixation devices. Patients with associated ligaments injuries and or severe chondral damage were excluded. The patients were randomly assigned to enter the control group (group A, standard post-operative rehabilitation) and the study group (group B, brace free accelerated rehabilitation). A CT scan was used to exactly determine the diameters of both femoral and tibial tunnels at various levels of lateral femoral condyle and proximal tibia, using a previously described method [17]. Measurements were done by an independent radiologist in a blinded fashion the day after the operation and at a mean follow-up of 10 months (range 9–11). Statistical analysis was performed using paired t-test. The mean femoral tunnel diameter increased significantly from 9.04 ± 0.05 (post-operative) to 9.30 ± 0.8 mm (follow-up) in group A and from 9.04 ± 0.03 to 9.94 ± 1.12 mm in group B. The mean tibial tunnel diameter increased significantly from 9.03 ± 0.04 to 10.01 ± 0.80 mm in group A and from 9.04 ± 0.03 to 10.60 ± 0.78 mm in group B. The increase in femoral and tunnel diameters observed in the study group was significantly higher than that observed in the control group. Our results suggest that bone tunnel enlargement after ACL reconstruction using hamstrings autograft can be increased by an accelerated, brace free, rehabilitation protocol.     

Revision anterior cruciate ligament reconstruction using a 2-stage technique with bone grafting of the tibial tunnel

BACKGROUND: Revision anterior cruciate ligament surgery is often considered a salvage procedure with limited goals. However, this limitation need not be the case. Similar to primary reconstruction, the goal should be to choose an appropriate graft and place it in an anatomical position in a good quality bone. The issue of good quality bone seems to have been ignored. HYPOTHESIS: A 2-stage anterior cruciate ligament revision reconstruction with bone grafting of the tibial tunnel and the use of a different femoral tunnel will produce measured knee laxity and International Knee Documentation Committee scores similar to a primary anterior cruciate ligament reconstruction. STUDY DESIGN: Case control study; Level of evidence, 3. METHODS: This prospective study involved 49 consecutive 2-stage anterior cruciate ligament revisions (group R) performed by a single surgeon from 1993 to 2000. Two-stage revision surgery was performed if the tibial tunnel from a previous reconstruction surgery would overlap (either partially or fully) the correctly placed revision tunnel. The first stage consisted of removal of the old graft and interfering metalwork, together with bone grafting of the tibial tunnel. After ensuring adequate bone graft incorporation using computed tomography scan, the second stage revision was undertaken. This stage comprised harvesting the autograft, its anatomical placement, and its adequate fixation. The results were compared with the results of a matched group of patients with primary anterior cruciate ligament reconstruction (group P). RESULTS: In group R, as meniscal and chondral lesions were more common, the International Knee Documentation Committee scores were lower than those of group P (61.2 for group R and 72.8 for group P; P = .006). Objective laxity measurement was similar in both groups (1.36 mm for group R and 1.2 mm for group P; P = .25). CONCLUSION: This study establishes that the laxity measurements achieved with a 2-stage revision anterior cruciate ligament reconstruction can be similar to those achieved after primary anterior cruciate ligament reconstruction, although the International Knee Documentation Committee rating is lower.     

The influence of tibial fixation on tunnel enlargement after hamstring tendon anterior cruciate ligament reconstruction

The retrospective study was designed to evaluate tibial-tunnel enlargement after anterior cruciate ligament reconstruction with hamstring autograft. Forty-three patients (43 knees) were enrolled, among whom a spiked washer was used for the tibial side fixation in 20 knees (Group SW) and the WasherLoc was used in 23 knees (Group WL). After an average 16 (range 12–32) months follow-up, the distance between the sclerotic margins of the tibial tunnel was measured at the joint level, and 1 and 2 cm distal to the joint level on the lateral view radiographs, from which the tibial-tunnel enlargement at each point (E1, E2, and E3 respectively) was determined. Anterior knee laxity was also measured using a KT-1000 or KT-2000 arthrometer at follow-up. E1, E2, and E3 were 2.3±1.3 mm (mean±standard deviation), 1.8±0.8 mm, and 1.5±0.8 mm respectively in Group SW, and 2.6±1.0 mm, 2.6±1.2 mm, and 2.9±1.6 mm in Group WL. Group WL had a larger mean value than Group SW at each level of measurement, with a statistically significant difference in E2 and E3. Fifty percent of the tunnels were the cone type in Group SW, whereas reversed cone-type tunnels were the most common (39%) in Group WL. The side-to-side difference in anterior knee laxity was –0.6±5.2 mm in Group SW and 1.8±9.0 mm in Group WL, which was significantly different between the groups. No statistical relationship was found between tunnel enlargement and side-to-side difference in anterior knee laxity in Group SW, whereas there was a slight negative correlation between E1 or E2 and anterior knee laxity in Group WL. It is possible that there is greater tension applied to the graft when the WasherLoc is used, which creates larger compressive forces on the posterior wall of the tibial tunnel by the graft. This was probably the reason for the greater tunnel enlargement and the high incidence of the reversed cone-type tunnel in Group WL.     

Reliability of tunnel angle in ACL reconstruction: two-dimensional versus three-dimensional guide technique

Purpose  

To compare the reliability of tibial tunnel position and angle produced with a standard ACL guide (two-dimensional guide) or Howell 65° Guide (three-dimensional guide) in the coronal and sagittal planes. In the sagittal plane, the dependent variables were the angle of the tibial tunnel relative to the tibial plateau and the position of the tibial tunnel with respect to the most posterior aspect of the tibia. In the coronal plane, the dependent variables were the angle of the tunnel with respect to the medial joint line of the tibia and the medial and lateral placement of the tibial tunnel relative to the most medial aspect of the tibia.     

The remnant preservation technique reduces the amount of bone tunnel enlargement following anterior cruciate ligament reconstruction

Purpose

The aim of the present study was to investigate the correlation between postoperative tunnel enlargement after ACLR and remnant tissue preservation using the hamstring tendon.

Methods

One hundred and ninety-two subjects (male, n = 101; female, n = 91; mean age 27.1) who had undergone double-bundle ACL reconstruction were included in the present study. The patients were divided into two groups: the remnant tissue preservation group (Group R) and the non-remnant tissue preservation group (Group N). Computed tomographic scans of the operated knee were obtained at 2 weeks and 6 months after surgery. The area of the tunnel aperture for the anteromedial femoral tunnel (FAMT), posterolateral femoral tunnel (FPLT), anteromedial tibial tunnel (TAMT), and posterolateral tibial tunnel (TPLT) was measured. The area at 2 weeks after ACLR was subtracted from the area at 6 months after ACLR and then divided by the area at 2 weeks after ACLR. The differences in the outcomes and characteristics of the two groups were evaluated.

Results

Seventy-seven knees were classified into Group R, and 115 knees were classified into Group N. The age, gender, and body mass index did not differ to a statistically significant extent. The percentages of FAMT and TAMT enlargement in Group R were significantly smaller in comparison with Group N (P = 0.003 and P = 0.03, respectively). The percentage of FPLT and TPLT enlargement in the two groups did not differ to a statistically significant extent.

Conclusion

The remnant-preserving technique reduces the amount of bone tunnel enlargement. The present findings indicate the advantages of the remnant-preserving ACLR technique, and therefore the remnant-preserving technique should be recommended.

Level of evidence

II.

     

Abnormal bone scans of the tibial tunnel 2 years after patella ligament anterior cruciate ligament reconstruction: correlation with tunnel enlargement and tibial graft length

Tibial bone tunnels were examined with bone scans 2 years after patella ligament ACL reconstruction in 68 patients. At 2 years, scan uptake at the tibial tunnel was increased in 29% of patients. Marked increase of scintigraphic uptake was associated with tibial tunnel enlargement of more than 35% and a graft length in the tibial tunnel over 14 mm. Scan uptake was correlated to tunnel enlargement (r = 0.64, P < 0.01) and tunnel enlargement was correlated to graft length inside the tibial tunnel (r = 0.59 P < 0.001). No correlation was found between scan uptake or tunnel enlargement and anterior laxity, sagittal tunnel position and subjective outcome. Scintigraphy indicates the enlarged tibial tunnels are filled with remodelling bone. Tibial fixation location influences ligament healing inside the tunnel: Return of osseous homeostasis at the tibial tunnel can take more than 2 years when fixation is more than 14 mm below the joint.