Effect of PEEK polymer on tunnel widening after hamstring ACL reconstruction

The purpose of this study was to evaluate the effect of the AperFix device (Cayenne Medical, Inc, Scottsdale, Arizona), composed of polyetheretherketone (PEEK) polymer, on tunnel widening after hamstring anterior cruciate ligament (ACL) reconstruction as compared with 2 other fixation devices: the TransFix (Arthrex, Inc, Naples, Florida) and the EndoButton (Smith & Nephew Endoscopy, Mansfield, Massachusetts). Sixty-seven patients with isolated total ACL ruptures who underwent arthroscopically assisted reconstruction using hamstring autografts at the authors' institution were included in the study. Patients were assigned into 1 of 3 groups in a nonrandomized fashion: AperFix (n=18), TransFix (n=29), and EndoButton (n=20). Mean follow-up was 30 months. Tunnel widening measurements were performed on anteroposterior and lateral digital plain radiographs taken in postoperative week 1 and at final follow-up. Laxity testing, Lysholm scoring, and arthrometric evaluation were performed.All 3 graft fixation devices resulted in significant tunnel widening in both tibial and femoral tunnels at final follow-up when compared with the immediate postoperative period. Tunnel widening between groups was not significantly different in terms of coronal and sagittal femoral tunnel diameters. Tibial tunnel diameter increase in the sagittal plane in the EndoButton group was significantly smaller than that in the TransFix and AperFix groups. No correlation was found between the amount of tunnel enlargement and clinical outcomes of ACL surgery. This study's findings suggest that tunnel enlargement after ACL reconstruction is influenced by the type of graft fixation on the tibial side irrespective of clinical outcome, and PEEK polymer does not have an effect on tunnel widening after hamstring ACL reconstruction.     

Interference screw divergence in femoral tunnel fixation during endoscopic anterior cruciate ligament reconstruction using hamstring grafts

Purpose:To compare the divergence angles between bioabsorbable interference screws inserted into the femoral tunnel with the screwdriver placed through the anteromedial portal to those inserted with the screwdriver placed through the tibial tunnel and to examine the effect of the femoral tunnel interference screws’ divergence angles on fixation strength of hamstring grafts after anterior cruciate ligament (ACL) reconstruction using hamstring grafts. Type of Study:Cadaveric biomechanical pullout study. Methods:ACL reconstruction was performed in 8 pairs of fresh-frozen human cadaveric knees using hamstring grafts fixed within the femoral tunnels using bioabsorbable interference screws. Within matched pairs, 1 screw was placed into the femoral tunnel using a screwdriver placed through the tibial tunnel (group 1), and in the other knee it was placed into the femoral tunnel using a screwdriver placed through the anteromedial portal (group 2). Radiographs were taken to measure the degree of divergence between the interference screw and the femoral tunnel. After disarticulation, pullout strength was then measured using a cyclic-loading model. Results:In group 2, there was significantly more divergence between the screw and the femoral tunnel compared with group 1, particularly in the sagittal plane (average 14.4° compared with 3.4°, P =.00014). With the number of specimens available for comparison, no significant difference was detected between the 2 groups with regard to 3 mm and 5 mm of pullout when cyclically loaded (P =.77 and.74, respectively). Conclusions: The increased technical difficulty, combined with the potential risks of tibial tunnel widening and graft damage, with placement of the screwdriver through the tibial tunnel for the purpose of decreasing femoral interference screw divergence in ACL reconstruction using hamstring grafts may not be justified.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 18, No 5 (May-June), 2002: pp 510–514     

The effect of soft-tissue graft fixation in anterior cruciate ligament reconstruction on graft-tunnel motion under anterior tibial loading

Purpose: To compare the motion of an anterior cruciate ligament (ACL) replacement graft within the femoral bone tunnel (graft-tunnel motion) when a soft-tissue graft is secured either by a titanium button and polyester tape (EndoButton fixation; Acufex, Smith & Nephew, Mansfield, MA) or by a biodegradable interference screw (Biointerference fixation; Endo-fix; Acufex, Smith & Nephew) An additional purpose was to evaluate the effect of the graft-tunnel motion on the kinematics of ACL-reconstructed knees and in situ force of the ACL replacement graft. Type of Study: Biomechanical experiment using an in vitro animal model. Methods: ACL reconstruction with a flexor tendon autograft was performed in 8 cadaveric knees of skeletally mature goats. The knee kinematics and the in situ force in the ACL replacement graft in response to anterior tibial loads were evaluated using the robotic/universal force-moment sensor testing system. The longitudinal and transverse graft-tunnel motion during anterior tibial loading was determined based on radiographic measurements parallel and perpendicular to the femoral bone tunnel, respectively. Results: In response to an anterior tibial load of 100 N, the longitudinal graft-tunnel motion for EndoButton fixation and Biointerference fixation was 0.8 ± 0.4 mm and 0.2 ± 0.1 mm, respectively (P < .05), whereas the transverse graft-tunnel motion was 0.5 ± 0.2 mm and 0.1 ± 0.1 mm, respectively (P < .05). Furthermore, the anterior tibial translation for EndoButton fixation (5.3 ± 1.2 mm) was also significantly larger than that for Biointerference fixation (4.2 ± 0.9 mm) (P < .05). With both fixations, however, no significant difference between the in situ forces in the ACL replacement graft and that in the intact ACL could be detected. Conclusions: EndoButton fixation of a soft-tissue graft via an elastic material resulted in significantly larger graft-tunnel motion, and consequently, greater anterior knee laxity compared with more rigid fixation using an interference screw closer to the intra-articular entrance of the bone tunnel. In terms of force distribution, the ACL replacement graft in both fixations still functioned as a primary restraint to an anterior tibial load close to the intact ACL.     

Biomechanical evaluation of six femurgraft-tibia complexes in ACL reconstruction

Soft tissue graft-tibial tunnel fixation is considered the weak point in reconstruction of the anterior cruciate ligament (ACL). We hypothesized that the biomechanical properties of fixation devices used in ACL reconstruction can be better evaluated by testing complete constructs (femoral tunnel fixation-graft-tibial tunnel fixation). Porcine knees were reconstructed with bovine digital extensor tendons using 6 different commercially available fixation device combinations, and biomechanically tested with cyclic loads (1000 cycles, 0–150 N, 0.5 Hz) and until failure (crosshead speed, 250 mm/min). The device combinations tested (in groups of 6) were EndoButton CL-BioRCI, Swing Bridge-Evolgate, Rifidfix-Intrafix, Bone Mulch- Washerlock, Transfix-Retroscrew, and Transfix-Deltascrew. Ultimate failure load, stiffness, slippage at cycles 1, 100, 500 and 1000 and mode of failure were evaluated. The statistical differences between pairs of groups were assessed with Student’s unpaired t test. The ultimate failure load of complexes made with the Swing Bridge- Evolgate was significantly higher than any other device (968 N; p<0.05), while that of devices made with Transfix-Retrofix was significantly lower than the others (483 N, p<0.05). The stiffness of Swing Bridge-Evolgate complexes was significantly higher than the others (270 N/mm, p<0.05). Regarding mode of failure, Rigidfix-Intrafix complexes showed a failure of the femoral fixation in all specimens. All failures of the other specimens occurred at the tibial side, except one specimen in the EndoButton CL-BioRCI group. Many commercially available tibial fixation devices showed biomechanically appreciable properties, sometimes better than femoral devices.     

Isolierter Bündelersatz bei Partialruptur des vorderen Kreuzbandes

Objective

Partial augmentation of isolated tears of the anteromedial and posterolateral bundle of the anterior cruciate ligament (ACL) with autologous hamstring tendons. The intact fibers of the ACL are preserved.

Indications

Symptomatic isolated tear of the anteromedial or posteromedial bundle of the ACL or rotational instability after ACL reconstruction with malplaced tunnels (e.g., high femoral position)

Contraindications

In revision cases: loss of motion due to malplaced ACL and excessive tunnel widening of the present tunnels with the risk of tunnel confluence.

Surgical technique

Examination of anterior–posterior translation and rotational instability under anesthesia. Diagnostic arthroscopy, repetition of the clinical examination under direct visualization of the ACL, meticulous probing of the functional bundles. Resection of ligament remnants, preparation/preservation of the femoral and tibial footprint. Harvesting one of the hamstring tendons, graft preparation. Positioning of a 2.4 mm K-wire in the anatomic center of the femoral anteromedial/posterolateral bundle insertion, cannulated drilling according to the graft diameter. Positioning of a 2.4 mm K-wire balanced according to the femoral tunnel at the tibia, cannulated drilling. Insertion of the graft and fixation.

Postoperative management

Analogous to that for ACL reconstruction.     

Outcome of double bundle anterior cruciate ligament reconstruction using crosspin and aperture fixation

Background:

Double bundle anterior cruciate ligament (DBACL) reconstruction is said to reproduce the native anterior cruciate ligament (ACL) anatomy better than single bundle anterior cruciate ligament, whether it leads to better functional results is debatable. Different fixation methods have been used for DBACL reconstruction, the most common being aperture fixation on tibial side and cortical suspensory fixation on the femoral side. We present the results of DBACL reconstruction technique, wherein on the femoral side anteromedial (AM) bundle is fixed with a crosspin and aperture fixation was done for the posterolateral (PL) bundle.

Materials and Methods:

Out of 157 isolated ACL injury patients who underwent ACL reconstruction, 100 were included in the prospective study. Arthroscopic DBACL reconstruction was done using ipsilateral hamstring autograft. AM bundle was fixed using Transfix (Arthrex, Naples, FL, USA) on the femoral side and bio interference screw (Arthrex, Naples, FL, USA) on the tibial side. PL bundle was fixed on femoral as well as on tibial side with a biointerference screw. Patients were evaluated using KT-1000 arthrometer, Lysholm score, International Knee Documentation Committee (IKDC) Score and isokinetic muscle strength testing.

Methods:

Out of 157 isolated ACL injury patients who underwent ACL reconstruction, 100 were included in the prospective study. Arthroscopic DBACL reconstruction was done using ipsilateral hamstring autograft. AM bundle was fixed using Transfix (Arthrex, Naples, FL, USA) on the femoral side and bio interference screw (Arthrex, Naples, FL, USA) on the tibial side. PL bundle was fixed on femoral as well as on tibial side with a biointerference screw. Patients were evaluated using KT-1000 arthrometer, Lysholm score, International Knee Documentation Committee (IKDC) Score and isokinetic muscle strength testing.

Results:

The KT-1000 results were evaluated using paired t test with the P value set at 0.001. At the end of 1 year, the anteroposterior side to side translation difference (KT-1000 manual maximum) showed mean improvement from 5.1 mm ± 1.5 preoperatively to 1.6 mm ± 1.2 (P < 0.001) postoperatively. The Lysholm score too showed statistically significant (P < 0.001) improvement from 52.4 ± 15.2 (range: 32-76) preoperatively to a postoperative score of 89.1 ± 3.2 (range 67-100). According to the IKDC score 90% patients had normal results (Category A and B). The AM femoral tunnel initial posterior blow out was seen in 4 patients and confluence in the intraarticular part of the femoral tunnels was seen in 6 patients intraoperatively. The quadriceps strength on isokinetic testing had an average deficit of 10.3% while the hamstrings had a 5.2% deficit at the end of 1 year as compared with the normal side.

Conclusion:

Our study revealed that the DBACL reconstruction using crosspin fixation for AM bundle and aperture fixation for PL bundle on the femoral side resulted in significant improvement in KT 1000, Lysholm and IKDC scores.     

The effect of outlet fixation on tunnel widening

Purpose: To compare the development of tibial tunnel widening after a standard bone–patellar tendon–bone autograft (BPTB) to a flipped BPTB that allows interference screw outlet fixation with a bone plug at both femoral and tibial tunnels, and to identify any observable clinical effect. The hypothesis of this study was that the outlet fixation achieved by the flipped BPTB technique results in diminished tunnel widening at the site of the bone plug. Type of Study: Nonrandomized control trial. Methods: The postoperative radiographs of 67 BPTB anterior cruciate ligament (ACL) reconstructions were retrospectively reviewed; 31 had conventional BPTBs and 36 had the bone plugs flipped at the tibial end to achieve interference screw fixation of the bone plug at the tibial outlet as well as the femoral outlet. Biodegradable interference screws (PLLA) were used in all cases, which facilitated tunnel measurements. One week after surgery, the maximal tibial bone tunnel widths were measured on anteroposterior and lateral radiographs 1 cm below the tibial plateau. These initial postoperative measurements were compared with measurement from radiographs taken annually thereafter. Clinical information including Lysholm, Tegner, IKDC activity, Lachman, pivot-shift, and range of motion data was also obtained and compared for the 2 groups. Results: In the conventional BPTB group, at an average follow-up of 28 months, 28 of 31 (90%) showed at least a 2-mm increase (20%) in the tibial tunnel width. The mean maximum tunnel width increase was 2.2 mm. In the flipped BPTB group, at an average follow-up of 31 months, none of these 36 showed any increase in tunnel size. In fact, 15 patients had no distinct tibial tunnel remaining and, of the other 21, the average remaining tunnel width was 3 mm. The clinical results evaluating the Tegner, Lysholm, IKDC activity levels, KT, and physical examination parameters showed no significant differences between these 2 groups. The tunnel width decreased during the first year, but remained unchanged after 12 months. No tunnel dilation was observed with bone plug outlet fixation while 90% of the conventional group had at least a 20% increase (P <.001). Conclusions: Outlet fixation with the flipped BPTB technique decreased the tibial tunnel width 1 cm below the plateau while 90% of the conventional BPTB patients demonstrated an average widening of 20%.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 19, No 5 (May-June), 2003: pp 485–492     

Tunnel enlargement 5 years after anterior cruciate ligament reconstruction: a radiographic and functional evaluation

Purpose

The aetiology and clinical significance of enlargement of bone tunnels following anterior cruciate ligament (ACL) reconstruction remains controversial. This phenomenon has been attributed to biological factors and mechanical factors. We wanted to study the amount of femoral and tibial tunnel enlargement 5 years post-ACL reconstruction. By standardizing the type of femoral fixation, we also wanted to determine whether the type of tibial fixation had any bearing to the amount of tibial tunnel enlargement.

Methods

All patients who underwent arthroscopic hamstring autograft ACL reconstruction between January 2000 and December 2000 were identified. All grafts were fixed with close-looped endobutton proximally. The grafts were fixed on the tibial side with staples or bioabsorbable interference screws. At a minimum of 5 years after surgery, these patients were recalled. They were assessed with Lysholm knee, Tegner activity and the IKDC Subjective and Objective forms and a KT-1000 arthrometer. The diameter of the bone tunnels and tunnel positions in the anterior–posterior and lateral radiographs were measured using digital callipers by a two blinded researchers.

Results

We found that the femoral tunnel enlarged more than the tibial tunnel. At 5 years, the mean tibial tunnel enlargement was 2.46 mm and the mean femoral tunnel enlargement was 3.23 mm. All 54 patients had endobutton femoral fixation. Of them, 34 patients had tibial graft fixation with staples (extracortical fixation) and 20 patients had tibial graft fixation with bioabsorbable interference screws (aperture fixation). The mean enlargement as measured by the two independent observers in the extracortical group was 1.98 mm (24.7 %)* and 1.51 mm (18.2 %)**compared to 3.27 mm (40.4 %)* and 2.92 mm (30.0 %)** in the aperture fixation group. This difference in tibial tunnel enlargement between the groups was significant (p < 0.001, mean difference 1.29 mm). However, this was not correlated with any significant difference in clinical outcome at 5 years.

Conclusion

We, like some authors, have shown that the use of interference screws in tibial fixation despite being aperture fixation actually has a greater amount of tibial enlargement. This lends weight to the biological theory to tunnel enlargement.     

Femoral bridge stability in double-bundle ACL reconstruction: impact of bridge width and different fixation techniques on the structural properties of the graft/femur complex

Background  The aim of this study was to evaluate the impact of different widths of the bony bridge between the femoral AM and PL bundle tunnel and different fixation techniques on the structural properties of the graft/femur complex in double-bundle ACL reconstructions. Hypothesis  Double-bundle ACL reconstruction with a bony bridge between AM and PL bundle tunnel of 1 mm results in significantly lower structural properties of the graft/femur complex when compared to a bridge of 2 and 3 mm. Interference screw fixation significantly lowers the structural properties when compared to cortical fixation. Study design  Controlled laboratory study. Methods  Double-bundle ACL reconstructions using different bridge widths (1 mm, 2 mm, and 3 mm bridge) were loaded to failure after a cyclic loading protocol (1,000 cycles 0–200 N) and the structural properties were compared to a single-bundle ACL reconstruction group (n = 10 in each group). The structural properties of using a cortical button fixation were then compared to interference screw fixation (2 mm bridge). Statistical analyses were performed using a Mann–Whitney test (P < 0.05). Results  Double-bundle reconstructions with cortical button fixation (1, 2, and 3 mm bridge) showed significantly higher ultimate failure loads and stiffness and significantly lower elongation compared to single-bundle reconstructions. Double-bundle ACL reconstructions with a 1 mm bridge showed significantly reduced structural properties of the graft/femur complex compared to a 2 or 3 mm bridge. Aperture fixation led to significantly lower ultimate loads when compared to cortical fixation. Conclusion  The bony bridge between the two femoral tunnels in double-bundle ACL reconstructions influences the stability of the graft/femur complex. Aperture fixation using interference screws shows inferior results when compared to cortical fixation. Clinical relevance  The results suggest that the indication for anatomical ACL reconstruction may include the size of the lateral femoral condyle. In small knees, a second femoral tunnel may be difficult to locate with a minimum bridge width of 2 mm.     

Double bundle revision of a malplaced single bundle vertical ACL reconstruction: ACL revision surgery using a two femoral tunnel technique

Background  Several factors influence the outcome after ACL reconstruction. One of the most important factors influencing the resulting knee kinematics and subjective instability is femoral tunnel placement. Revision can be necessary if the femoral tunnel is drilled transtibial in the roof of femoral notch (mismatch). Hypothesis  Double bundle reconstruction using two femoral tunnels and one tibial tunnel technique can be used in revision of a primary vertical ACL reconstruction. Study design  Case series (level of evidence III). Methods  ACL revision was performed in five patients complaining instability after primary transtibial ACL reconstruction. Clinical examination, X-ray and CT analysis were performed to evaluate objective knee laxity, tunnel placement and widening. In all patients a technique using two femoral tunnels in a two medial portal technique and one tibial tunnel was used. Patients were reevaluated at a follow up of 24 months. Results  Preoperatively, pivot shift tests were 2+ in three and 1+ in the remaining two patients. Lachman test was found to be positive in all patients (4 patients, 2+ firm endpoint; 1 patient, 2+ soft endpoint). X-rays showed a femoral tunnel position at 11.30 (1 patient) and 12.00 o’clock (4 patients). In one patient significant tibial tunnel enlargement was to be found. At a follow up of 24 months, KT 1000 was <2 mm side to side difference and the pivot shift test was negative in all patients. Conclusion  Revision of a primary vertical ACL reconstruction can be safely performed using a double bundle reconstruction with two femoral tunnels in a two medial portal technique and one tibial tunnel technique. The femoral tunnel need to be located in the anatomic origin of the AM and PL bundle. Clinical relevance  Femoral tunnel placement in the notch of the intercondylar notch should be avoided. In these cases without significant tunnel enlargement, a primary double bundle revision with two femoral and one tibial tunnel can be performed.     

Correlation of tunnel widening and tunnel positioning with short-term functional outcomes in single-bundle anterior cruciate ligament reconstruction using patellar tendon versus hamstring graft: a prospective study

Objective

To study the correlation between tunnel widening and tunnel position with short-term functional outcomes post-ACL reconstruction with patellar tendon and hamstring autografts in young adults.

Materials and methods

A total of 33 patients who underwent ACL reconstruction between October 2013 and February 2015 were included and followed up for 6 months. A standardized surgical technique was used for each graft type. Intra-op arthroscopy findings and drilled tunnel diameters were noted. They were followed up for 3 and 6 months. Radiological assessment was done at 3 and 6 months with clinical score assessment at 6 months.

Results

At 6 months, clinical scores were comparable in both groups. Tunnel widening in both femoral and tibial tunnel at 3 and 6 months were significantly higher in STG group (p values <0.05). The rate of widening was higher in 0–3 months and reduced in 3–6 months. There was statistically significant negative correlation between femoral tunnel widening by CT and IKDC score at 6 months (p value 0.049). We found a positive correlation between posterior positioning of femoral tunnel and Lysholm and IKDC scores. The correlation with Lysholm scores was statistically significant (p value 0.046).

Conclusion

To conclude, tunnel widening is more with hamstrings graft. Femoral tunnel widening has significant negative correlation with that of IKDC scores at 6 months. Posterior femoral tunnel positioning and Lysholm scores at 6 months had significant correlation.

     

High incidence of tunnel widening after anterior cruciate ligament reconstruction with transtibial femoral tunnel placement

Background

This study evaluated the incidence, amount, morphology and clinical significance of bone tunnel widening (TW) at a mean 5-year period after anterior cruciate ligament reconstruction (ACLR) with a transtibial drilling technique.

Methods

Fifty-nine patients undergoing primary ACLR using quadrupled hamstring autografts, biodegradable transfemoral pins for femoral-sided and 2-mm oversized interference screws for tibial-sided graft fixation were followed up at a mean 61?months postoperatively. Patients were examined clinically and by MRI. Tunnel cross-sectional areas (CSA) were related to drill diameters, which were significantly correlated with radiographic tunnel sizes. Tunnel morphologies were assessed and their positions determined using an anatomical coordinate system.

Results

CSA had more than doubled in all segments measured (p?<?0.0001) except at the femoral notch level. Greatest CSA increases were found at the femoral graft suspension point (122?%) and at the central tibial tunnel segment (134?%). 54 (92) and 56 (95?%) patients had significant TW, i.e., CSA increase of more than 50?%, in at least one tunnel segment femorally and tibially. Four different tunnel morphologies were observed, of which the linear type was most often encountered on either side. Mean side-to-side difference in anterior-posterior laxity was 1.0?±?1.4?mm, while Lysholm, IKDC and Tegner acitivity scores were 90?±?12, 84?±?15 and 4 (1–9); clinical outcomes were not found to be correlated with tunnel sizes and morphologies as were tunnel positions and tunnel sizes.

Conclusions

This study demonstrates that considerable TW occurs in virtually all patients in the mid term after ACLR using a transtibial drilling technique with ‘high’ femoral tunnel positions. Yet, neither amount nor morphology or tunnel position does affect knee stability or function.     

Bone tunnel enlargement after ACL reconstruction using autologous hamstring tendons: a CT study

Purpose: To evaluate prospectively the increase in the size of the tibial and femoral bone tunnel following arthroscopic anterior cruciate ligament (ACL) reconstruction with quadrupled-hamstring autograft. Methods: Twenty-five consecutive patients underwent arthroscopic ACL reconstruction with quadrupled-hamstring autograft. Preoperative clinical evaluation was performed using the Lysholm knee score, Tegner activity level, and International Knee Documentation Committee forms and a KT-1000 arthrometer (side to side). Computed tomography (CT) of the femoral and tibial tunnel was performed on the day after operation in all cases and at mean follow-up of 10 months (range 9–11 months).Results: All of the clinical evaluation scales performed showed an overall improvement. The postoperative anterior laxity difference was <3 mm in 16 patients (70%) and 3–5 mm in seven patients (30%). The mean average femoral tunnel diameter increased significantly (3%) from 9.04±0.05 mm postoperatively to 9.3±0.8 mm at 10 months; tibial tunnel increased significantly (11%) from 9.03±0.04 mm to 10±0.8 mm. There were no statistically significant differences between tunnel enlargement, clinical results, and arthrometer evaluation. Conclusions: The rate of tunnel widening observed in this study seems to be lower than that reported in previous studies that used different techniques. We conclude that an anatomical surgical technique and a less aggressive rehabilitation process influenced the amount of tunnel enlargement after ACL reconstruction with doubled hamstrings.

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Résumé But: évaluer prospectivement l’augmentation de taille des tunnels osseux après reconstruction arthroscopique du LCA par les ischio-jambiers. Méthode: 25 patients avaient été opérés. L’évaluation pré-opératoire avait été faite avec le score de Lysholm, les critères IKDC et de niveau d’activité Tegner et la mesure bilatérale avec l’arthromètre KT-1000. Un scanner des tunnels était réalisé dans tous les cas le jour suivant la chirurgie et à un suivi moyen de 10 mois (9–11). Résultats: Tous les scores cliniques montraint une amélioration globale. La différence de laxité antérieure après l’intervention était de moins de 3mm pour 16 patients (70%) et de 3 à 5 mm pour 7 (30%). Le diamètre moyen du tunnel fémoral augmentait significativement (3%) de 9,04±0,05 mm en post-opératoire à 9,3±0,8 mm à 10 mois ; le tunnel tibial augmentait (11%) de 9,03±0,004 à 10±0,8 mm. Il n’y avait pas de corrélation significative entre l’élargissement des tunnels, les résultats cliniques et les mesures à l’arthromètre. Conclusions: La proportion d’élargissement des tunnels observée dans cette étude semble plus faible rapportées avec des techniques différentes. Nous pensons qu’une technique très anatomique et une rééducation peu agressive influence l’élargissement des tunnels dans la reconstruction du LCA par les ischio-jambiers.

     

Trantibial anterior cruciate ligament double bundle reconstruction technique: two tibial bundle in one tibial tunnel

The anterior cruciate ligament (ACL) consists of two functional bundles that behave independently throughout the range of knee motion. Many two-bundle reconstruction techniques have been introduced to restore the function of the two bundles of the ACL. Generally, two femoral and two tibial tunnels are made during the surgery for a two-bundle ACL reconstruction. However, the procedure is technically demanding and time consuming. This paper describes one-tibial-two-femoral ACL double bundle reconstruction technique with a sextuple-stranded hamstring autograft. The anteromedial femoral tunnel is made using transtibial drilling technique and posterolateral femoral tunnel is made using outside-in technique. The two bundles in a single tibial tunnel are separated using biodegradable interference screw. Stable and adequate femoral fixation of the two bundles with a transtibial fixation and bioabsorbable screw can be obtained. This technique is relatively simple, and replicates the anatomy and differential behavior of the two native bundles of ACL more effectively.     

Graft failure versus graft fixation in ACL reconstruction: histological and immunohistochemical studies in rabbits

The causes of graft failure after anterior cruciate ligament (ACL) reconstruction are multifactorial including the methods of graft fixation. The purpose of this study was to examine the ACL graft failure in three different methods of graft fixations including interference screw fixation, suture-post fixation and combined interference screw and suture-post fixation. We hypothesized that the fixation method after ACL reconstruction can affect the graft healing in tibial tunnel. Eighteen New Zealand white rabbits were categorized into three groups according to the method of fixation in unilateral ACL reconstruction with long digital extensor autograft. Histological examination demonstrated that the combined fixation and suture-post fixation groups showed significantly better integration between tendon and bone (P = 0.04). In immunohistochemical analysis, the combined fixation and suture-post fixation groups showed significantly higher BMP-2 and VEGF expressions than interference screw (P < 0.01). The tendon–bone healing after ACL reconstruction was affected by the method of graft fixation. Combined fixation with interference screw and suture-post reduced graft-tunnel micromotion and improved the graft healing in tibial tunnel.     

Accuracy in tunnel placement for ACL reconstruction. Comparison of traditional arthroscopic and computer-assisted navigation techniques.

The purpose of this randomized, prospective study was to compare accuracy in tunnel placement as performed with a traditional arthroscopic anterior cruciate ligament (ACL) reconstruction technique and with KneeNavTM ACL, a computer-assisted surgical navigation technique. Two surgeons experienced in ACL reconstruction, but inexperienced in computer-assisted surgical navigation technique, each randomly used traditional arthroscopic guides or KneeNavTM ACL to drill a tunnel in twenty identical foam knees. Placement of the resulting tibial and femoral tunnels was measured with a computer-assisted digitizing method and compared to traditional biplanar radiographs. Statistical analysis with Student's t-test was used to compare the distance from the ideal tunnel placement to the femoral and tibial tunnels. Accuracy of tunnel placement with KneeNavTM ACL was significantly better than that obtained with the traditional arthroscopic technique. Distances from the ideal tunnel placement to the femoral and tibial tunnels were 4.2 +/- 1.8 mm (mean +/- SD) and 4.9 +/- 2.3 mm, respectively, for the traditional arthroscopic technique, and 2.7 +/- 1.9 mm (femur) and 3.4 +/- 2.3 mm (tibia) for KneeNavTM ACL. These differences were statistically different. Tunnel placement for ACL reconstruction with KneeNavTM ACL, an image-based, computer-assisted surgical navigation device with a simple and intuitive interface, was more accurate than with the traditional arthroscopic technique.     

Kombination von VKB-Ersatzplastik und hoher tibialer Umstellungsosteotomie

Objective

Replacement of the anterior cruciate ligament (ACL) with an autologous tendon together with a high tibial osteotomy (HTO) in one operation.

Indication

Simultaneous symptomatic ACL insufficiency and symptomatic varus osteoarthritis.

Contraindications

Risk of a higher complication rate for a one-stage procedure, e.g., in loss of motion due to soft tissue contracture, loss of motion due to insufficiency of a existent ACL replacement with tunnel malplacement, tunnel widening of an existent ACL replacement with the risk of tunnel confluence, infection in a former operation. Varus osteoarthritis with a hollow posteromedial tibial plateau (knee abuser). Exclusion criteria include PLC insufficiency, lateral or posterolateral instability, lateral arthritis.

Surgical technique

Osteotomy: placement of the two K-wires from the medial tibia about 4–5 cm below the medial tibial plateau towards the lateral hinge about 2 cm below the lateral tibial plateau. Mobilization of the long fibers of the medial collateral ligament distal of the osteotomy, mobilization of the pes anserinus tendons. Frontal and axial osteotomy with an oscillating saw. Completion and opening of the osteotomy with chisels. Opening of the osteotomy with a spreader according to the new leg axis of the preoperative planning. Fixation of the osteotomy with an angle stable plate (PPP Arthrex, Tomofix Synthes). In case of a distal osteotomy of the hiberosity fixation with 2 screws. Arthroscopy: positioning of a 2.4 mm K-wire in the center of the remnant femoral ACL insertion, cannulated drilling according to the graft diameter. Positioning of a 2.4 mm K-wire in the center of the remnant tibial ACL insertion, cannulated drilling. In the case of interference of the tibial tunnel with one of the osteotomy screws, removal of the screw and finishing of the tunnel preparation. Measurement of the length and insertion of the respective osteotomy screw. Insertion of the graft and fixation with a button-wire construct at the femur and with a bioabsorbable interference screw and a lag screw at the tibia.

Postoperative management

Postoperative management relating to weight bearing rehabilitation follows osteotomy rules, while range of motion rehabilitation follows the ACL protocol.     

关节镜下横杆式固定重建膝前十字韧带的中期疗效观察

目的 评价关节镜下自体腘绳肌腱移植、横杆式固定(transfix)重建膝关节前十字韧带(anterior cruciate ligament,ACL)的中期临床疗效.方法 自2002年8月至2003年12月对38例膝关节ACL断裂患者应用自体腘绳肌腱重建ACL、股骨端采用横杆式固定、胫骨端采用界面螺钉固定.男21例,女17例;年龄19～48岁,平均28.4岁;左膝24例,右膝14例.运动伤27例,交通伤2例,跌倒扭伤2例,余7例无明显外伤.急性损伤6例,陈旧性损伤32例.术前体检:前抽屉试验阳性35例,弱阳性1例,阴性2例;Lachman征阳性37例,弱阳性1例.以Lysholm评分评价中期临床疗效,以MRI及X线观察移植物以及骨隧道变化情况.结果 38例患者中36例获得随访(随访率94.7％),随访时间6.3～7.6年,平均6.8年.所有患者关节活动度正常,Lysholm评分由术前(64.4±4.52)分提高到(85.6±4.60)分,差异有统计学意义.X线及MRI发现3例股骨及胫骨隧道均扩大,5例股骨隧道扩大,3例胫骨隧道近端扩大.未见关节间隙变窄.1例患者在术后4年因外伤再次致ACL断裂,行关节镜下ACL翻修术,采用同种异体肌腱移植物,股骨端及胫骨端采用可吸收挤压钉固定.结论 应用腘绳肌腱、股骨侧横杆式、胫骨侧界面挤压螺钉固定重建膝关节ACL可以获得较为满意的关节活动度及关节稳定性,中期疗效佳.     

A New Harvest Site for Bone Graft in Anterior Cruciate Ligament Revision Surgery

During revision anterior cruciate ligament (ACL) surgery, femoral interference screws frequently require removal. This may lead to significant tunnel widening and possible graft fixation failure as a result. Solutions include drilling the revision tunnel in a different location, using stacked interference screws, or using bone graft to fill the defect. Autogenous iliac crest graft and allograft are both used, but there are significant comorbidities associated with each. We developed a new technique for harvesting autogenous bone graft that avoids many of the complications associated with other graft sources. By use of the existing surgical incision from the initial harvest of the bone–patellar tendon–bone autograft, bone from the medial tibial metaphyseal safe zone is harvested via an OATS tube harvester (Arthrex, Naples, FL). A bone plug 1 mm larger in size than the femoral defect is harvested and arthroscopically inserted via a press-fit technique. At 3 months after bone grafting, patients undergo revision ACL reconstruction. The proximal tibial metaphysis is a safe bone graft harvest site in revision ACL surgery and offers an effective method for filling large bony defects, allowing anatomic reconstruction of the ACL after bone healing has occurred. Furthermore, it eliminates the problems associated with allograft or use of a remote graft donor site.