Arthroscopic reconstruction of the anterior cruciate ligament using double anteromedial and posterolateral bundles

We propose a method for repairing the anterior cruciate ligament which takes advantage of the multifascular nature of the ligament to achieve better physiological anteroposterior and rotational stability compared with conventional methods. Arthroscopic reconstruction of the anteromedial and posterolateral bundles of the ligament closely reproduces normal anatomy. We have used this technique in 92 patients with anterior cruciate ligament laxity and present here the mid-term results. The hamstring tendons (gracilis and semitendinosus) are harvested carefully to obtain good quality grafts. Arthroscopic preparation of the notch allows careful cleaning of the axial aspect of the lateral condyle; it is crucial to well visualize the region over the top and delimit the 9 h-12 h zone for the right knee or the 12-15 h zone for the left knee. The femoral end of the anteromedial tunnel lies close to the floor of the intercondylar notch, 5 to 10 mm in front of the posterior border of the lateral condyle, at 13 h for the left knee and 11 h for the right knee. The femoral end of the posterolateral tunnel lies more anteriorly, at 14 h for the left knee and 10 h for the right knee. The tibial end of the posterolateral tunnel faces the anterolateral spike of the tibia. The tibial end of the anteromedial tunnel lies in front of the apex of the two tibial spikes half way between the anteromedial spike and the anterolateral spike, 8 mm in front of the protrusion of the posteriolateral pin. The posterolateral graft is run through the femoral and tibial tunnels first. A cortical fixation is used for the femoral end. The femoral end of the anteromedial graft is then fixed in the same way. The tibial fixation begins with the posterolateral graft with the knee close to full extension. The anteromedial graft is fixed with the knee in 90 degrees flexion. Thirty patients were reviewed at least six months after the procedure. Mean age was 28.2 years. Mean overall IKDC score was 86% (36% A and 50% B). Gain in laxity was significant: 6.53 preoperatively and 2.1 postoperatively. Most of the patients (86.6%) were able to resume their former occupation 2 months after the procedure. The different components of the anterior cruciate ligament and their respective functions have been the object of several studies. The anteromedial bundle maintains joint stability during extension and anteroposterior stability during flexion. The posterolateral bundle contributes to the action of the anteromedial bundle with an additional effect due to its position: rotational stability during flexion. In light of the multifascicular nature of the anterior cruciate ligament and the residual rotational laxity observed after conventional repair, our proposed method provides a more anatomic reconstruction which achieves better correction of anteroposterior and rotational stability. This technique should be validated with comparative trials against currently employed methods.     

Long Term Results of Surgery for Non-Acute Anteromedial Rotatory Instability of the Knee

Seventy-eight patients treated by extraarticular reconstruction including pes anserinus transfer for anteromedial rotatory instability of the knee were reinvestigated 16-47 months (mean 28) after operation. Function before and after operation was assessed by means of a knee rating score. Of these patients, 94 per cent showed a higher score after operation. Twenty per cent showed full recovery with no limitation of knee function whatsoever. The follow-up score was higher with preserved medial meniscus function than when this structure had been removed. When not initially torn, the medial meniscus tended to become involved with time. Mild laxity in extension, possibly indicative of a posterior cruciate injury previously underestimated or not observed, was found in 15 per cent of the patients. No correlation was found between late knee function and the interval between injury and operation or the interval between operation and follow-up examination.

The long term results were good. Extraarticular reconstruction is thus indicated in cases of chronic rotatory instability of the anteromedial type. Routine meniscectomy is not recommended in these patients, however. Signs possibly indicating posterior cruciate ligament involvement should be carefully looked for, as even minor posterior cruciate injury, easily overlooked, may influence the late results.     

Long term results of surgery for non-acute anteromedial rotatory instability of the knee.

Seventy-eight patients treated by extraarticular reconstruction including pes anserinus transfer for anteromedial rotatory instability of the knee were reinvestigated 16--47 months (mean 28) after operation. Function before and after operation was assessed by means of a knee rating score. Of these patients, 94 per cent showed a higher score after operation. Twenty per cent showed full recovery with no limitation of knee function whatsoever. The follow-up score was higher with preserved medial meniscus function than when this structure had been removed. When not initially torn, the medial meniscus tended to become involved with time. Mild laxity in extension, possibly indicative of a posterior cruciate injury previously underestimated or not observed, was found in 15 per cent of the patients. No correlation was found between late knee function and the interval between injury and operation or the interval between operation and follow-up examination. The long term results were good. Extraarticular reconstruction is thus indicated in cases of chronic rotatory instability of the anteromedial type. Routine meniscectomy is not recommended in these patients, however. Signs possibly indicating posterior cruciate ligament involvement should be carefully looked for, as even minor posterior cruciate injury, easily overlooked, may influence the late results.     

Drilling the Femoral Tunnel During ACL Reconstruction: Transtibial Versus Anteromedial Portal Techniques

Incorrect bone tunnel position, particularly on the femoral side, is a frequent cause of failed anterior cruciate ligament reconstruction. Several studies have reported that drilling the femoral tunnel through the anteromedial portal allows a more anatomical placement on the lateral femoral condyle and higher knee stability than does transtibial reconstruction.In the current study, the femoral tunnel was drilled with transtibial (n=6) and anteromedial (n=6) portal techniques in 12 cadaveric knees. With appropriate landmarks inserted into bone tunnels, the direction and length of the tunnels were determined on anteroposterior and lateral radiographs. Knee stability was evaluated with a KT1000 arthrometer (MEDmetric Corporation, San Diego, California) and pivot shift test, comparing the pre- and postoperative values of both techniques. Finally, all knees were dissected to enhance vision of the insertion of the reconstructed ligament. The anteromedial portal technique led to better placement of the femoral tunnel in the coronal and sagittal planes, with higher knee stability according to the pivot shift test but not the KT1000 arthrometer.Anatomical and clinical results reported in the literature on transtibial and anteromedial portal techniques are controversial, but most of studies report better results with the anteromedial portal technique, especially regarding rotational stability. The current cadaveric study showed that the anteromedial portal technique provided better tunnel placement on the lateral femoral condyle in the coronal and sagittal planes, with an improvement in the rotational stability of the knee.     

Die Zwei-Bündel-Technik – eine anatomische Rekonstruktion des vorderen Kreuzbandes

OBJECTIVE: To improve the rotational stability of the knee by anatomic reconstruction of the anterior cruciate ligament by socalled double-bundle technique using anteromedial and posterolateral grafts from native semitendinosus and gracilis. The grafts are fixed with bioabsorbable screws utilizing aperture fixation. INDICATIONS: Complete tear of the anterior cruciate ligament with positive Lachman sign and pivot shift. CONTRAINDICATIONS: Open growth plate. Osteoarthritis > grade 1 according to J?ger & Wirth. Age > or = 50 years with low sports activity (relative contraindication). SURGICAL TECHNIQUE: Graft harvest of the semitendinosus and gracilis tendons via a 3-cm horizontal skin incision parallel to pes anserinus and preparation of the tendons as double-looped grafts. Arthroscopy, resection of the stump of the anterior cruciate ligament, and clearance of its origin and insertion. Tunnel placement by means of aiming devices in the following order: tibial posterolateral, tibial anteromedial, femoral anteromedial (transtibial or via the anteromedial portal in 120 degrees flexion), and femoral posterolateral (via additional medial arthroscopic portal). The anteromedial (semitendinosus tendon) and posterolateral (gracilis tendon) bundles are passed through the tunnels and fixed on the femoral side. Tibial fixation of the graft by bioresorbable interference screw with knee flexion of 45 degrees (anteromedial) and 10 degrees (posterolateral). POSTOPERATIVE MANAGEMENT: Depending on the degree of swelling, rehabilitation with partial weight bearing for 14 days and full range of motion. Return to sports after 6 months, no contact sports until 9 months. RESULTS: From May 2004 to June 2005, anatomic double-bundle reconstruction was performed in 19 patients (13 male, six female, average age 31 years [18-48 years]) with isolated anterior cruciate ligament rupture without concomitant lesions. Clinical follow-up examination on average at 21.3 months (16-30 months) postoperatively. The Lysholm Score improved from an average of 65.2 to 94.5 points (75-100 points). The IKDC (International Knee Documentation Committee) Score yielded nine very good and ten good results in the relevant subgroups of motion, effusion and ligament stability. Measurement of anteroposterior translation with the KT-1000 instrument at 134 N showed increased translation of 1.8 mm (-2 to 5 mm) compared to the contralateral knee.     

胫骨平台后内侧骨折的两种手术入路比较

［摘要］ 目的 探讨两种手术入路内固定术对胫骨平台后内侧骨折（PMF?TP）的疗效影响。方法 选取2014年3月至2017年3月本院收治的PMF?TP患者80例,依据完成手术的不同路径,每组40例,常内组给予常规膝关节后内侧入路手术治疗,改内组给予改良髌旁内侧入路手术治疗,比较两组手术、并发症、骨折复位、膝关节功能情况。结果 改内组术中出血量、手术、住院、负重锻炼、骨折愈合时间明显低于常内组,差异有统计学意义（P<0.05）;改内组并发症率明显低于常内组,差异有统计学意义（P<0.05）;改内组术后6个月骨折复位、膝关节功能优良率明显高于常内组,差异有统计学意义（P<0.05）。结论 改良髌旁内侧入路较常规的后内侧入路相对简单且安全。     

Intra-articular or extra-articular substitution of cruciate ligament--a critical study (author's transl)]

Intra- and extra-articular methods of cruciate ligament substitution are available for treating old anteromedial knee-joint instability. Twelve patients with intra-articular cruciate ligament substitution (median third of the patellar ligaments as free transplant) and 24 patients with extra-articular cruicate ligament substitution (operation according to Nciholas) were examined with particular reference to improved stability as follow-up examinations, the results being subjected to comparative evaluation. Intra-artricular cruciate ligament substitution reduces or eliminates the pre-operative instability of the joint which is due to insufficiency of the cruciate liagment, whereas the extra-articular cruciate ligament substitution produces a significantly more frequent reduction of elimination of the instability of the valgus position and of the anteromedial instability. The combination of both methods to remove anteromedial instability of the knee joint may seem a very useful solution of the problem, but it should be limited to a restricted group of patients because it involves also contain disadvantages which make it unsuitable for indiscriminate application.     

In situ calibration of miniature sensors implanted into the anterior cruciate ligament. Part I: Strain measurements

The goals of this study were to (a) evaluate the differential variable reluctance transducer as an instrument for measuring tissue strain in the anteromedial band of the anterior crudciate ligament, (b) develop a series of calibration curves (for simple states of knee loading) from which resultant force in the ligament could be estimated from measured strain levels in the anteromedial band of the ligament, and (c) study the effects of knee flexion angle and mode of applied loading on ouput from the transducer. Thirteen fresh-frozen cadaveric knee specimens underwent mechanical isolation of a bone cap containing the tibial insertion of the anterior cruciate ligament and attachment of a load cell to measure resultant force in the ligament. The transducer (with barbed prongs) was inserted into the anteromedial band of the anterior cruciate ligament to record local elongation of the instrumented fibers as resultant force was generated in the ligament. A series of calibration curves (anteromedial bundle strain versus resultant force in the anterior cruciate ligament) were determined at selected knee flexion angles as external loads were applied to the knee. During passive knee extension, strain readings did not always follow the pattern of resultant force in the ligament; erratic strain readings were often measured beyond 20° of flexion, where the anteromedial band was slack. For anterior tibial loading, the anteromedial band was a more active contributor to resultant ligament force beyond 45° of flexion and was less active near full extension; mean resultant forces in the range of 150–200 N produced strain levels on the order of 3–4%. The anteromedial band was also active during application of internal tibial torque; mean resultant forces on the order of 180–220 N produced strains on the order of 2%. Resultant forces generated by varus moment were relatively low, and the anteromedial band was not always strained. Mean coefficients of variation for resultant force in the ligament (five repeated measurements) ranged between 0.038 and 0.111. Mean coefficients of variation for five repeated placements of the strain transducer in the same site ranged from 0.209 to 0.342. Insertion and removal of this transducer at the anteromedial band produced observable damage to the ligament. In our study, repeatable measurements were possible only if both prongs of the transducer were sutured to the ligament fibers.     

两种关节镜手术入路治疗外侧盘状半月板损伤的比较

目的对比采取常规膝前外、内侧入路和膝高位前外侧、高位极前内侧入路治疗外侧盘状半月板损伤的临床效果。 方法选取2016年01月至2017年12月成都体育学院附属体育医院收治的膝外侧盘状半月板患者57例为研究对象,年龄≤60岁,单侧发病(Outerbridge分级<3级),无下肢骨折及膝关节其他损伤。依据在术中手术入路的不同将其分为常规组和改良组。常规组(26例),采取常规膝前内侧、前外侧入路进行手术;改良组(31例),采取膝高位前外侧入路和高位极前内侧入路进行手术。记录两组患者的手术时间、关节腔内积液量,采用配对t检验和卡方检验比较术前和术后3个月的膝前视觉模拟(VAS)评分、Lysholm评分和MRI复查情况。 结果所有患者获得随访,平均(15.1±2.1)个月,术后切口均Ⅰ级愈合。两组患者Watanabe分型比较,差异无统计学意义(P>0.05)。两组患者术后3个月Lysholm评分均较术前显著提高(常规组：t＝-19.719,P<0.05;改良组：t＝-30.094,P<0.05),且改良组术后Lysholm评分高于常规组(P<0.05)。两组患者术前膝前VAS评分比较,差异无统计学意义(t＝ -0.255,P>0.05),常规组患者术后3个月的膝前VAS评分较术前显著提高(t＝-9.603,P<0.05),而改良组患者术后3个月的膝前VAS评分与术前类似(t＝-1.139,P>0.05)。常规组手术时间(t＝14.434,P<0.05)、术后关节腔积液量明显高于改良组(t＝40.989,P<0.05)。MRI复查两组患者均未出现半月板不愈合情况(χ²＝0.035,P>0.05)。 结论两种手术入路均可完成外侧盘状半月板损伤的处理,并获得良好的的近期疗效。采取膝高位前外侧、高位极前内侧入路,镜下视野大,同时避免对髌下脂肪垫刨消,缩短手术时间,减轻患者术后膝前疼痛。     

Lateral patellar retinaculum tension in patellar instability

The patellar retinaculum is important in patellar tracking. However, little attention has been paid to the biomechanics of the retinaculum. This study assessed the change in tension of the lateral patellofemoral ligament before and after anteromedial tibial tubercle transfer for patellar instability. Twenty-seven knees in 21 patients were studied and the mean age of the patients at surgery was 19 years. A buckle transducer was clamped on the lateral patellofemoral ligament and the transducer was calibrated to zero with the knee at full extension. The knee then was flexed 30 degrees, 60 degrees, 90 degrees, and 120 degrees, and the transducer recorded changes in tension within the lateral patellofemoral ligament. After anteromedial tibial tubercle transfer, lateral patellofemoral ligament tension was measured in the same manner. Although average lateral patellofemoral ligament tension increased with knee flexion with the maximum at 120 degrees flexion, these changes showed four different patterns measuring variability of patellar instability. An increase of lateral patellofemoral ligament tension after anteromedial tibial tubercle transfer meant that lateral retinacular release should be done concurrently to balance patellar tracking. This information may be useful in deciding the appropriate surgical procedure for each patient.     

The forgotten popliteus muscle. Its usefulness in correction of anteromedial rotatory instability of the knee. A preliminary report

The popliteus muscle is an important factor in stability of the knee. Advancement of the popliteus muscle and tendon complex was useful for surgical correction of anterior and anteromedial instability in 8 cases.     

Transposition of the semitendinosus tendon for early repair of medial and anteromedial laxity of the knee

In 15 patients with acute medial (N = 8) or anteromedial (N = 7) laxity of the knee, reconstruction of the torn ligaments was combined with the use of the semitendinosus tendon as a dynamic extra-articular stabilizer. The postoperative regimen consisted of early mobilization in a mobile cast with full weight bearing. An evaluation 1 to 3 years after surgery revealed good results in 14 cases, and one fair result as graded using the Marshall score (mean score 45.3, SD 2.9). Isokinetic measurements of knee flexion and extension showed no loss of strength. Equally good results have been reported in conservatively treated isolated MCL lesions. In case of a combination of a MCL lesion and an ACL lesion the results reported are usually worse. This treatment regimen seems to be a good concept in acute anteromedial laxity of the knee and cannot be considered anything but an alternative in isolated MCL lesions.     

关节镜下半腱肌腱和股薄肌腱双隧道重建前十字韧带

目的探讨关节镜下联合应用半腱肌腱和股薄肌腱重建前十字韧带(anteriorcruciateligament,ACL)的方法及疗效。方法回顾自1998年4月～2000年5月在关节镜下联合应用半腱肌腱和股薄肌腱重建ACL的患者12例。于ACL前内侧束和后外侧束的附着部分别钻直径4.5mm的隧道,用半腱肌腱重建前内侧束,股薄肌腱重建后外侧束,保留半腱肌腱和股薄肌腱的附着点,在股骨隧道外口将半腱肌腱和股薄肌腱打结固定,不行内固定。所有患者术前及术后18个月行膝关节屈曲30°、60°、90°前抽屉试验,Lysholm评分方法评定膝关节功能。结果术后随访18～43个月,平均26个月。术前所有患者前抽屉试验均为阳性,术后9例阴性,2例屈膝30°位阳性,1例屈膝30°、60°位阳性。术前Lysholm评分为40～58分,平均50.5分,手术后18个月为62～92分,平均85分,总优良率为91.7%。结论应用半腱肌腱和股薄肌腱联合重建ACL,术后膝关节动态稳定性好,疗效满意。     

外固定支架结合胫骨近端锁定钢板治疗胫骨平台复杂骨折

目的：通过应用外固定支架结合胫骨近端锁定钢板治疗胫骨平台骨折,观察临床疗效,探讨胫骨平台复杂骨折的治疗方法。方法：2006年2月至2008年10月,采用外固定支架结合胫骨近端锁定钢板治疗复杂胫骨平台骨折12例,男8例、女4例;年龄23～59岁,平均38岁。骨折按Sehazker分型：Ⅴ型7例,Ⅵ型5例。术中使用前内侧切口及前外侧切口,于胫骨外侧置入锁定钢板进行内固定。观察术前及术后X线片胫骨平台塌陷及高度丢失情况,对膝关节功能使用HSS评分法评分。结果：12例均获随访,时间4—18个月,平均9．79个月,骨折平均愈合时间3．1个月。骨折愈合11例,延迟愈合1例,无骨筋膜室综合征及下肢深静脉栓塞。术前、术后X线片对照检查未发生Ⅱ期胫骨平台塌陷及高度丢失,无对线不良,膝关节屈曲90°～110°。HSS评分术后平均（75．50±10．01）分,较术前平均（21．50±11．68）分有所提高。结论：外固定支架结合胫骨近端锁定钢板治疗复杂胫骨平台骨折提供了持续稳定的固定,防止骨折的Ⅱ期移位和膝关节力线的畸形,可以保护膝关节周围软组织,减少手术并发症,膝关节功能满意。     

Anatomische vordere Kreuzbandersatzoperation mittels Semitendinosus- und Grazilissehne in fremdmaterialfreier Press-fit-Technik

An innovative technique for anterior cruciate ligament (ACL) reconstruction has been developed in 1998 which allows the grafts to be fixed by press-fit to the femoral and tibial tunnel without any hardware. The semitendinosus (ST) and gracilis tendons (GT) are built into a sling by tying a knot with the tendon ends and securing the knot after conditioning by sutures. For the femoral tunnel the anteromedial porta is used. The correct anatomic position of the single femoral tunnel is checked using intraoperative lateral fluoroscopy by placing the tip of a K-wire to a point between the anteromedial and posterolateral bundle insertion sites. A femoral bottleneck tunnel is drilled to receive the knot of the tendons. The tendon loops filled the tibial tunnel without any suture material. The loops are fixed at the tibial tunnel outlet with tapes over a bone bridge. Between 1998 and 1999 a prospective randomized study (level 1) was conducted comparing this technique with a technique using bone-patellar-tendon graft and press-fit fixation without hardware. In conclusion it was found that implant-free press-fit ACL reconstruction using bone-patella-tendon (BPT) and hamstring tendon (HT) grafts proved to be an excellent procedure to restore stability and function of the knee. Using hamstring tendons (ST and GT) significantly lower donor site morbidity was noted. Kneeling and knee walking pain persisted to be significantly more intense in the BPT up to 9 years after the operation. Re-rupture rates, subjective findings, knee stability and isokinetic testing showed similar results for both grafts. This is the first level I study which demonstrates cartilage protection by ACL reconstruction as long as the meniscus is intact at index surgery, shown by bilateral MRI analysis 9 years post-operation. There was no significant difference in the average grade of chondral and meniscus lesions between BPT and HT and in comparison of the operated to the intact knee, except for grade 3-4 lesions found at the 9 year follow-up, which were significantly higher in the BPT group.     

新版膝关节评分系统在评价单髁关节置换术的应用分析

目的使用单髁关节置换的患者样本验证新版膝关节评分系统(New-KSS)评分系统的效应性以及内部一致性。 方法采用2012年由美国膝关节协会设计推出的New-KSS评价单髁关节置换治疗膝前内侧单间室骨关节炎患者疗效,在行初次单髁关节置换的住院患者中对参与本研究的患者按照符合膝内侧单间室骨关节炎的纳入标准进行筛选,并排除双侧、多间室、炎症性关节炎及近期感染的患者,并且要求患者在术前、术后3个月及术后12个月完成New-KSS评分量表以及膝关节损伤和骨关节炎评分(KOOS)量表。利用克隆巴赫信度系数(Cronbach’ s alpha)分析新版膝关节评分系统New-KSS的信度,同时通过Spearman相关系数分析其效度。验证New-KSS评分在评价单髁关节置换疗效的效应性以及内部一致性。 结果65名符合入组标准的患者参加了研究,根据New-KSS各亚维度的Cronbach’ s α在0.70～0.91变化,反映其具有较高的内在信度。术前、术后次评分各维度效应值Cohen’d系数范围在1.83～4.43,提示其具有较好的效应性。New-KSS与KOOS量表相应维度之间的结构效度理想,说明New-KSS与KOOS在评价同一对象时具有较好的一致性。 结论通过分析相关数据发现,New-KSS在评价单髁关节置换疗效具有较好的效应性和内部一致性;且New-KSS量表具有较好的跨时间差异适应性。     

Genetic influences in the aetiology of anteromedial osteoarthritis of the knee

We report a study of 112 patients with primary anteromedial osteoarthritis of the knee and their families. Sibling risk was determined using randomly selected single siblings. Spouses were used as controls. The presence of symptomatic osteoarthritis was determined using an Oxford knee score of > or= 29 supported by a Kellgren and Lawrence radiological score of II or greater. Using Fisher's exact test we found that there was a significant increased risk of anteromedial osteoarthritis (OA) relative to the control group (p = 0.031). The recurrence risk of anteromedial OA to siblings was 3.21 (95% confidence interval 1.12 to 9.27). These findings imply that genetic factors may play a major role in the development of anteromedial OA of the knee.     

Total prosthetic replacement of ankylosed knees

Total knee arthroplasty is reliable for achieving pain relief, increasing range of motion, maintaining stability, and improving walking ability. In this study, the results in knees with a preoperative range of motion of 0 were reviewed to determine whether an ankylosed knee can be replaced successfully. In eight of nine knees, the results with regard to pain, stability, and walking ability were good at follow-up evaluations greater than 2 years after operation. Range of motion was also improved in all knees but was still limited. Motion achieved was in a physiologic arc with all knees having full, or nearly full, extension.     

膝关节伸直位僵硬松解手术入路探讨

目的探讨采用多种手术入路进行膝关节伸直位僵硬松解的可能性。方法对22例膝关节伸直位僵硬采用手术松解治疗,其中16例采用原手术切口,包括外侧1例,前外侧9例,前内侧3例和前正中入路3例,对6例无法利用原手术切口松解的病人,5例采用前外侧切口,另1例电击伤后膝内侧异位骨化病人采用前内侧切口。结果应用多种手术入路股四头肌成形术均完成松解手术,17例病人切断了纤维化和挛缩的股中间肌。术中完全松解后可以达到的被动屈曲角度,除1例僵硬时间25年的病例松解到130°外,其他病人均达到150°以上。出院时膝关节主动屈曲度为101.8°±12.9°,与术前比较有显著提高(P0.01)。平均随访时间11.8(5~21)个月,随访结束时膝关节主动屈曲度112.5°±18.4°,较手术前明显增加(P(0.01);膝关节功能平均(95.7±4.5)分,明显高于术前(P0.01)。结论采用外侧、前外侧、前内侧和前正中等多种手术入路进行股四头肌成形术均可有效解除导致膝关节伸直位僵硬的因素,恢复膝关节的屈曲功能,术后积极康复在关节功能的恢复过程中起着十分重要的作用。     

In vivo anterior cruciate ligament length pattern assessment secondary to differences in the femoral attachment under loading condition using image-matching techniques

Background

The anterior cruciate ligament is composed of two functional bundles and is crucial for knee function. There is limited understanding of the role of each individual bundle and the influence on length pattern due to difference in bone tunnel position under loading conditions throughout the range of motion. We measured point to point length between the femoral and tibial footprints of the ligament throughout the range of motion in normal knees, under normal loading conditions, and investigated length pattern changes secondary to differences in the femoral footprint. We hypothesized that anteromedial and posterolateral bundles have complementary roles, and the ligament length pattern is influenced by the footprint position.