Tripled semitendinosus anterior cruciate ligament reconstruction with Endobutton fixation: a 2-3-year follow-up study of 35 patients

We evaluated the clinical outcome of tripled semitendinosus tendon ACL reconstruction with femoral Endobutton (Acufex, Smith&Nephew, Andover, MA) and tibial Suture Washer (Acufex, Smith&Nephew, Andover, MA) (n 29) or post screw fixation (n 6) in 35 patients on an average of 28 (20-37) months after surgery. On the basis of IKDC criteria, 22 patients showed a normal or nearly normal knee function and 25 patients had a KT 1000 maximal manual side-to-side difference of < or =5 mm at follow-up. Subjectively, 28 patients graded their knee function as normal or nearly normal. The average Lysholm score was 88 points, average OAK score 90 points and average modified HSS score 93 points. 19 patients reached their preinjury level of activity at follow-up. The postoperative Lachman test was < or =1+ in 24 patients and 24 patients also showed an absent pivot shift. Significant bone tunnel enlargement occurred in 26 patients on the femoral side and in 23 patients on the tibial side. We found no correlation between bone tunnel enlargement and clinical outcome. The clinical outcome of tripled semitendinosus tendon ACL reconstruction with Endobutton fixation on the femoral side was not entirely satisfactory. The procedure was associated with a high incidence of bone tunnel enlargement in this series.     

Tripled semitendinosus anterior cruciate ligament reconstruction with Endobutton fixation: A 2-3-year follow-up study of 35 patients

We evaluated the clinical outcome of tripled semitendinosus tendon ACL reconstruction with femoral Endobutton (Acufex, Smith&Nephew, Andover, MA) and tibial Suture Washer (Acufex, Smith&Nephew, Andover, MA) (n 29) or post screw fixation (n 6) in 35 patients on an average of 28 (20-37) months after surgery. On the basis of IKDC criteria, 22 patients showed a normal or nearly normal knee function and 25 patients had a KT 1000 maximal manual side-to-side difference of ≤5 mm at follow-up. Subjectively, 28 patients graded their knee function as normal or nearly normal. The average Lysholm score was 88 points, average OAK score 90 points and average modified HSS score 93 points. 19 patients reached their preinjury level of activity at follow-up. The postoperative Lachman test was ≤1+ in 24 patients and 24 patients also showed an absent pivot shift. Significant bone tunnel enlargement occurred in 26 patients on the femoral side and in 23 patients on the tibial side. We found no correlation between bone tunnel enlargement and clinical outcome. The clinical outcome of tripled semitendinosus tendon ACL reconstruction with Endobutton fixation on the femoral side was not entirely satisfactory. The procedure was associated with a high incidence of bone tunnel enlargement in this series.     

Bone tunnel enlargement after anterior cruciate ligament reconstruction with semitendinosus tendon using Endobutton fixation on the femoral side

We evaluated 29 knees with a minimum follow-up of 2 years after anterior cruciate ligament (ACL) reconstruction using doubled autogenous semitendinosus tendons. On the femoral side, a 5-mm Mersilene tape (Ethicon, Norderstedt, Germany) with an Endobutton (Acufex Microsurgical, Mansfield, MA) was used. The tendon was fixed on the tibial side with two staples. Regarding the IKDC score, 66% of the patients were graded as normal or nearly normal. The anterior laxity side-to-side difference (KT 1000, man-max-drawer) was under 3 mm in 55% and under 5 mm in 90%. Radiographs taken in the lateral and anteroposterior projections of the knee showed sclerotic bone tunnel margins. The diameter of the bone tunnels were measured, corrected for magnification, then compared with the original reamed diameter to determine any change in size. Enlargement of at least 2 mm was identified in 72% of the femoral tunnels and 38% of the tibial tunnels. No correlation was found concerning the enlargement of the tunnel and the IKDC score or the residual joint laxity. We conclude that using an Endobutton-Mersilene construct in ACL reconstruction leads to femoral and tibial bone tunnel enlargement at follow-up of 2 years. (Arthroscopy 1998 Nov-Dec;14(8):810-5.)     

A new arthroscopic method for reconstructing the anterior and posterior cruciate ligaments using a single-incision technique: simultaneous grafting of the autogenous semitendinosus and patellar tendons.

We established a simultaneous reconstruction method for ruptured anterior and posterior cruciate ligaments (ACL, PCL) using a single-incision technique. Residual PCL was used to determine the position of bone tunnel for ACL reconstruction. The bone tunnel position on the tibia for PCL reconstruction was arthroscopically confirmed by conducting through debridement from the posteromedial portal. Reconstruction substitutes were patellar-tendon bone-tendon-bone for ACL, and semitendinosus tendon for PCL. In the fixation procedure, the PCL substitute was fixed using the Endobutton (Smith & Nephew, Andover, MA) and a ceramic button, and the ACL substitute was fixed with an interference screw. During the surgery, radiographic monitoring and the PCL guide system were not required.     

Technical Note A New Arthroscopic Method for Reconstructing the Anterior and Posterior Cruciate Ligaments Using a Single-Incision Technique: Simultaneous Grafting of the Autogenous Semitendinosus and Patellar Tendons

Summary: We established a simultaneous reconstruction method for ruptured anterior and posterior cruciate ligaments (ACL, PCL) using a single-incision technique. Residual PCL was used to determine the position of bone tunnel for ACL reconstruction. The bone tunnel position on the tibia for PCL reconstruction was arthroscopically confirmed by conducting through debridement from the posteromedial portal. Reconstruction substitutes were patellar-tendon bone-tendon-bone for ACL, and semitendinosus tendon for PCL. In the fixation procedure, the PCL substitute was fixed using the Endobutton (Smith & Nephew, Andover, MA) and a ceramic button, and the ACL substitute was fixed with an interference screw. During the surgery, radiographic monitoring and the PCL guide system were not required.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 15, No 8 (November), 1999: pp 871–876     

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.     

Effect of compaction drilling during ACL reconstruction with hamstrings on postoperative tunnel widening

Type of study This study investigates whether the amount of tibial and femoral bone tunnel enlargement following anterior cruciate ligament (ACL) reconstruction with hamstrings can be reduced by compaction bone tunnel drilling. Methods Patients undergoing primary ACL reconstruction with four-strand hamstrings (n = 26) were matched to either extraction drilling (n = 13) or compaction drilling (n = 13). Extracortical femoral fixation was by means of a 20 mm Endobutton CL and tibial fixation was by resorbable interference screw. A CT scan was performed on the second postoperative day and an average of 4 months (range 3.8–5 months) postoperatively in all patients. Tunnel enlargement was determined by digitally measuring the widths perpendicular to the long axis of the tunnels on an oblique coronal and axial plane. The CT measurements were compared to the intraoperative drill diameter. Results With extraction drilling the average tibial tunnel diameter proximal to the interference screw increased from 8.5 to 10.4 mm (P < 0.0001) and the average femoral tunnel from 8.0 to 10.6 mm (P < 0.0001). With compaction drilling it increased from 8.2 to 10.0 mm (P < 0.0001) and from 7.6 to 9.7 mm (P < 0.002), respectively. Tunnel widening was 22% on the tibial side for both groups and 33 versus 28% on the femoral side (P = 0.09) for extraction versus compaction drilling. Conclusion There was a significant tibial and femoral tunnel widening on CT an average of only 4 months following ACL reconstruction with hamstrings. Compaction drilling with a stepped router did not prove to reduce the postoperative tunnel widening significantly. Tunnel widening was higher on the femoral side which could be related to the extracortical femoral fixation technique. Level of evidence Level 4. No benefits in any form have been received, or will be received, from a commercial party related directly or indirectly to the subject of this article.     

Prospective randomized comparison of endobutton versus cross‐pin femoral fixation in hamstring anterior cruciate ligament reconstruction with 2‐year follow‐up

Background: To determine if there is a different clinical outcome after TransFix versus endobutton femoral fixation in hamstring anterior cruciate ligament (ACL) reconstruction. Methods: Twenty‐nine patients were randomized into either Endobutton (Smith & Nephew, Andover, MA, USA) (n= 13) or TransFix (Arthrex, Naples, FL, USA) (n= 16) femoral fixation in hamstring ACL reconstruction. The distal fixation was with a bioabsorbable interference screw. The evaluation methods were clinical history and examination, KT1000 arthrometry for laxity as well as the International Knee Documentation Committee (IKDC) scores over a 2‐year time frame. Results: There were no significant differences between the study groups preoperatively. For the 2‐year follow‐up, 11 patients in the Endobutton group and 13 patients in the TransFix group were available (greater than 80%). No statistical differences between the two groups were found at the 1‐ or 2‐year follow‐up examinations. At the 2‐year follow‐up, 72.7% of the Endobutton and 84.6% of the TransFix group patients were in the IKDC A or B categories. Additional procedures postoperatively occurred more frequently in the TransFix group. Conclusions: There were no significant differences in the results for either technique of femoral fixation. Level of Evidence: Level I.     

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.     

Arthroscopic anterior cruciate ligament reconstruction using autogenous hamstring tendon graft without detachment of the tibial insertion

This article describes a modified arthroscopic technique of anterior cruciate ligament reconstruction using quadrupled hamstring tendon graft. The autogenous semitendinosus and gracilis grafts are harvested without detachment of the tibial insertion. To obtain longer grafts, the accessory tibial insertions of the hamstring tendons are dissected. The EndoButton (Acufex Microsurgical, Andover, MA) is used for femoral fixation and two spiked staples are used for tibial fixation in a belt buckle fashion. Then the residual anterior laxity is restored by additional absorbable interference screw fixations. In this technique, more viable graft is obtained and more firm distal fixation is achieved by preservation of the tibial insertion of hamstring tendons.     

Influence of the postoperative activity level on tibial bone tunnel enlargement and functional treatment results following anterior cruciate ligament reconstruction using a patellar tendon autograft

AIM: This study was performed to evaluate the influence of the postoperative activity level on tibial bone tunnel enlargement following anterior cruciate ligament reconstruction using a mid-third patellar tendon autograft. METHODS: A clinical and radiological assessment was performed on 50 patients (21 male, 29 female, mean age 32 years, range 18 to 57 years) following ACL reconstruction using a patellar tendon autograft. The average follow-up examination was performed 18 (12 to 30) months after the operation. RESULTS: 33 patients (66 %) developed a tibial bone tunnel enlargement > 1 mm. We found a positive correlation (+ 0.59) of the grade of activity and the muscle status (+ 0.56) to the tibial bone tunnel enlargement. Patients with a major tibial bone tunnel enlargement performed at a higher (p < 0.05) postoperative activity grade (5.2 versus 4.1 in the Tegner grading), rated higher in the Lysholm (88 versus 77 points) and IKDC scores (p < 0.05) and reported a better subjective functional outcome (p < 0.05). There was no significant correlation of the results of the knee stability tests and the age of the patients to the grade of tibial bone tunnel enlargement. CONCLUSIONS: In ACL reconstruction using a patellar tendon autograft we recommend early rehabilitation as the concomitant tibial bone tunnel enlargement does not significantly influence the clinical outcome or knee stability.     

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.     

腘绳肌腱结合双固定技术重建前交叉韧带

目的探讨采用腘绳肌腱股骨端胫骨端双固定技术重建前交叉韧带(ACL)的可行性及近期疗效。方法对25例ACL损伤行关节镜下ACL重建术,采用笔者自行设计双监视法解剖等长重建技术建立股骨胫骨隧道。移植物股骨端用Endobutton钢板和Rigidfix固定,胫骨端用Bio-Intrafix和Stample门形加压钉固定。结果本组获随访12～18(13.76±1.61)个月,未发现滑膜炎、韧带断裂、活动度明显障碍等并发症。根据Lysholm膝关节功能评分,术前评分:20～48(31.32±8.71)分;术后1年评分:90～98(94.96±2.56)分(t=37.69,P<0.01)。结论在腘绳肌腱重建ACL中应用股骨端胫骨端双固定技术具有手术操作简便,固定牢固,效果可靠的优点,值得推广。     

Comparison of ACL fixation devices using cadaveric grafts

We evaluated two newer forms of femoral fixation of hamstring grafts for anterior cruciate ligament reconstruction, the Endobutton direct (Smith and Nephew, Andover, MA) and Femoral intrafix (Depuy Mitek, Raynham, MA), and compare them to devices that have been evaluated in the literature, the AXL Crosspin (Biomet, Warsaw, IN) and Biotransfix II (Arthrex, Naples, FL). Paired hamstring tendon allografts were fixed in the femoral tunnel of 24 cadaveric bovine knees (6 per group) according to each device's specifications. The free ends (tibial sides) were fixed to the materials testing machine via custom-made cryo-clamps. In Phase I, single load to failure and stiffness were evaluated, and in Phase II, peak displacement was evaluated while cyclic loading was performed over 1000 cycles. One-way analyses of variance were performed to test for differences between groups. There were no significant differences in failure load (p = 0.42) or stiffness (p = 0.39) between the fixation devices. There was also no significant difference in peak displacement measured during the cyclic loading phase (p = 0.32). Our findings suggest that the newer generation devices, Endobutton direct and Femoral intrafix, have similar strength in single load to failure and similar peak displacement during cyclic loading as compared with clinically proven Crosspin techniques. These newer devices, which are designed to accommodate for more anatomic femoral tunnel placement, may provide a reasonable alternative without compromising biomechanical properties.     

保留残端半腱肌和股薄肌双股双隧道解剖重建前交叉韧带的临床研究

目的探讨关节镜下半腱肌股薄肌保留残端双股双隧道解剖重建前交叉韧带(ACL)的疗效。方法回顾自2006年1月～2008年1月,本组在关节镜下联合应用半腱肌腱和股薄肌腱双股双隧道重建ACL患者20例其中男18例,女2例,年龄17～46岁(平均31.5岁)。取腱器分别切取半腱肌、股薄肌编织成股,保留前叉韧带在股骨、胫骨的附着点残端,于ACL前内侧束和后外侧束附着部分别钻隧道,用半腱肌腱重建前内侧束,股薄肌腱重建后外侧束,以enderbutton悬吊固定股骨端,挤压螺钉固定胫骨端肌腱。所有患者术前及术后12个月行前抽屉试验、Lachman试验、Lysholm评分方法评定膝关节功能。结果术后随访14～48个月,平均31个月。术前患者前抽屉试验均为阳性,Lachman试验阳性13例,术后前抽屉试验3例屈膝60°位阳性,1例屈膝30°位阳性,其余均转阴性。5例Lachman试验仍阳性,但患者术后无膝关节不稳。2例患者术后胫骨前伤口瘢痕红肿凸起,给予切开引流后良好愈合。用Lysholm膝关节功能评分法评定术后疗效,术前评分为38～49分,平均43.5分,术后14个月为69～92分,平均80.5分,优13例,良5例,可2例,优良率为90.0%。结论应用自体肌腱双股双隧道重建ACL,术后膝关节动态稳定性好,疗效满意。     

前交叉韧带重建术后骨道增宽的临床研究

目的分析前交叉韧带（ACL）重建术后骨道增宽的发生率、增宽程度、骨道形状、相关因素及其与临床效果的关系。方法回顾性研究应用胭绳肌腱重建ACL手术后骨道的变化,通过X线片测量ACL重建术后的骨道直径。对51例患者行ACL重建手术,其中男性30例,女性21例。所有患者均获随访,平均随访时间16个月。主要研究及观察指标：患者性别、年龄、身高等因素,移植物的固定方式,随访时的关节活动度、膝关节稳定性检查（KT2000）及肌力恢复情况,以及股骨和胫骨的骨道直径、骨道位置和角度等。数据分析采用统计学卡方检验及相关性分析。结果前交叉韧带重建术后的骨道增宽率股骨85％-94％,胫骨65％;增宽程度股骨51％-53％,胫骨40％～44％。胫骨骨道增宽的形态以O型（冠位片）及V型（矢位片）最常见。骨道增宽与年龄、身高及体重指数相关。股骨骨道位置偏前会引起股骨骨道的增宽,股骨骨道角或胫骨骨道角越小,则股骨骨道越容易增宽。结论以腘绳肌腱为移植物重建前交叉韧带手术,术后骨道增宽的发生率与程度,股骨骨道较胫骨骨道明显。骨道增宽与患者年龄、身高以及骨道定位相关,其中股骨和胫骨骨道的位置及角度是引起术后骨道增宽的主要因素之一。骨道增宽与KT2000结果和术后肌力恢复情况相关。     

ACL重建股骨隧道定位及固定方法研究

目的探讨关节镜下应用半腱肌、股薄肌肌腱重建膝前交叉韧带时股骨隧道定位及固定方法。方法经临床及膝关节镜检查诊断的膝前交叉韧带损伤者86例采取镜下修复,分别应用经由内向外及由外向内2种定位方法行股骨隧道定位;股骨隧道固定分别应用Endobutton、Rigidfix及可吸收挤压螺钉3种方法。结果经随访10～26个月,Lachman征、前抽屉试验均为阴性,Lysholm评分从28分到70分,平均56.65分。结论股骨端隧道由内向外定位方法（通过胫骨隧道）创伤略小,适用于Endobutton、Rigidfix等,但受胫骨隧道位置及角度影响,要使股骨端隧道定位点与前交叉韧带股骨外髁解剖止点完全吻合,必须建立精确位置及角度的胫骨隧道。而股骨端隧道由外向内定位方法创伤略大,适用于股骨端挤压螺钉固定,定位点不受胫骨隧道影响,与前交叉韧带股骨外髁解剖止点较易吻合;而各种股骨端固定方法各有利弊,选择最佳的股骨隧道及固定方法将有助于减少术后并发症。     

Establishing a Popliteal Portal Using the METRx System Under Ultrasound Guidance

This report describes a special technique for safe establishment of a popliteal portal with the METRx system (Medtronic Sofamor Danek, Memphis, TN) under ultrasound guidance with the patient in the awake state. Herbert screws located at the posterior tibial plateau were removed via this portal in a minimally invasive way. Before surgery, we performed surface mapping of the screw tract with an image intensifier and target needling under ultrasound guidance. The METRx system was used to establish the soft-tissue corridor along the guide pin. Screw removal and tibial plateau resurfacing were performed with the Acufex Mosaicplasty system (Smith & Nephew Endoscopy, Andover, MA). In our review of the literature, no similar method establishing the knee popliteal portal was found. The method is recommended especially for minimally invasive surgery in regions rich with neurovascular structures.     

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.     

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.