Both medial and lateral bucket-handle meniscus tears associated with chronic ACL injury: A rare presentation of triple-PCL sign

BackgroundSeveral types of meniscal tear could be presented in both acute and chronic anterior cruciate ligament injury. The incidence of bucket-handle meniscus tears can be up to 30% of the overall meniscus tears cases. The case of both compartment (medial and lateral) bucket-handle meniscus is rarely occurred.CaseA case of both medial and lateral bucket-handle meniscus tears was reported in a male of 21 years old. The patient also had a chronic anterior cruciate ligament injury. The magnetic resonance imaging also showed a rare presentation of the triple-PCL sign with the sagittal view. Arthroscopic surgery with a meniscus repair and anterior cruciate ligament reconstruction was performed on the patient.ConclusionsSeveral specific imaging signs including triple-PCL sign could be presented in a rare case of both medial and lateral bucket-handle meniscus tears. Recognition of this sign is important to have accurate preoperative diagnosis and proper treatment plan.     

关节镜下前交叉韧带重建后内侧和外侧半月板同期移植术

目的 探讨全关节镜下前交叉韧带重建后内侧和外侧半月板同期移植的微创手术技术.方法 2008年8月对1例实施膝关节双束双通道前交叉韧带重建、内侧和外侧半月板切除的患者,在关节镜下实施内侧和外侧半月板同期移植微创手术.内侧半月板移植采用前后角骨栓固定方法,外侧半月板移植采用前后角骨桥固定方法.术后结果采用VAS疼痛评分、Cysholm评分和国际膝关节评分委员会(IKDC)分级评价.关节稳定性检查包括Lachman试验、抽屉试验和轴移试验.结果 术后随访26个月,患者膝关节屈曲、伸直和负重行走功能正常.VAS膝关节疼痛评分较术前降低2分,Lysholm评分较术前升高20分.IKDC分级由术前C级上升到B级.膝关节稳定性检查基本正常.术后1年MRI检查显示,重建前交叉韧带连续性完整,内侧和外侧移植异体半月板外形均较好,内侧半月板后角和外侧半月板前角有轻微萎缩.术后18个月关节镜复检观察到,外侧和内侧移植半月板均愈合良好,形态完整,但前角表面均有轻度磨损现象.结论 对膝前交叉韧带损伤和内、外侧半月板切除的患者,在前交叉韧带重建术后同期实施内侧和外侧半月板移植术可以尽量恢复膝关节的稳定性和力学平衡,对年轻患者是可供选择的治疗方式.术中建议采用同一供体的内侧和外侧异体半月板,制作各骨道时须注意其方向以避免骨道相互交通.

Abstract：

Objective To discuss the minimal invasive arthroscopic surgery technique and clinical results of both the medial and lateral meniscal transplantation following the anterior cruciate ligament reconstruction with double bundles and bone tunnels.Methods In August 2008 a minimal invasive surgery of both the medial and lateral meniscal allograft transplantation following anterior cruciate ligament reconstruction was preformed for 1 case with both the medial and lateral menicectomy by arthroscopic surgery.The method of two bone plugs attached on tibial plateau was employed for medial meniscal allograft transplantation and the technique the bridge in slot for lateral meniscal allograft transplantation.The VAS,Lysholm score and IKDC rating were recorded before and after operation.The stability of knee was assessed by Lachman test,drawer sign and pivot shift test.Results The patient was followed up 26 month after the operations.The degrees of knee flexion,extension and function of walk were normal.The Lachman test,drawer sign and pivot shift test were nearly normal.The VAS after operation was 2 points lower than that before operation.The Lysholm score post-operation was 20 points higher than pre-operation.The IKDC became B degree in late following-up from C degree before the operation.MRI revealed anterior cruciate ligament graft was continuous and the meniscal allograft was normal shape on year 1 after the operation.The posterior horn of medial meniscal allograft and anterior corner of lateral meniscal allograft showed slightly shrunk.The second-look arthroscopy showed that the healing occurring between meniscal allograft and the capsule and meniscal allograft was normal shape on month 18 after the operation.The anterior horn of medial and lateral meniscus was slightly worn.Conclusions Both the medial and lateral meniscal transplantation following the anterior cruciate ligament reconstruction in appropriately selected patients with the medial and lateral meniscus-deficient knee may recover the knee mechanic balance and stability,which is a option of treatment for that young and activity patients.It is proposed that the medial and lateral meniscal grafts harvested from a single donator.Attention should be paid to the direction of the bone tunnels fixing the horns of the meniscus in order to avoid communication with the tunnels of anterior cruciate ligament reconstruction.     

Anterior cruciate ligament deficiency alters the in vivo motion of the tibiofemoral cartilage contact points in both the anteroposterior and mediolateral directions

BACKGROUND: Quantifying the effects of anterior cruciate ligament deficiency on joint biomechanics is critical in order to better understand the mechanisms of joint degeneration in anterior cruciate ligament-deficient knees and to improve the surgical treatment of anterior cruciate ligament injuries. We investigated the changes in position of the in vivo tibiofemoral articular cartilage contact points in anterior cruciate ligament-deficient and intact contralateral knees with use of a newly developed dual orthogonal fluoroscopic and magnetic resonance imaging technique. METHODS: Nine patients with an anterior cruciate ligament rupture in one knee and a normal contralateral knee were recruited. Magnetic resonance images were acquired for both the intact and anterior cruciate ligament-deficient knees to construct computer knee models of the surfaces of the bone and cartilage. Each patient performed a single-leg weight-bearing lunge as images were recorded with use of a dual fluoroscopic system at full extension and at 15 degrees , 30 degrees , 60 degrees , and 90 degrees of flexion. The in vivo knee position at each flexion angle was then reproduced with use of the knee models and fluoroscopic images. The contact points were defined as the centroids of the areas of intersection of the tibial and femoral articular cartilage surfaces. RESULTS: The contact points moved not only in the anteroposterior direction but also in the mediolateral direction in both the anterior cruciate ligament-deficient and intact knees. In the anteroposterior direction, the contact points in the medial compartment of the tibia were more posterior in the anterior cruciate ligament-deficient knees than in the intact knees at full extension and 15 degrees of flexion (p < 0.05). No significant differences were observed with regard to the anteroposterior motion of the contact points in the lateral compartment of the tibia. In the mediolateral direction, there was a significant lateral shift of the contact points in the medial compartment of the tibia toward the medial tibial spine between full extension and 60 degrees of flexion (p < 0.05). The contact points in the lateral compartment of the tibia shifted laterally, away from the lateral tibial spine, at 15 degrees and 30 degrees of flexion (p < 0.05). CONCLUSIONS: In the presence of anterior cruciate ligament injury, the contact points shift both posteriorly and laterally on the surface of the tibial plateau. In the medial compartment, the contact points shift toward the medial tibial spine, a region where degeneration is observed in patients with chronic anterior cruciate ligament injuries.     

陈旧性前十字韧带损伤的诊断

目的评估前抽屉试验、Lachman试验、轴移试验和MRI在陈旧性前十字韧带损伤诊断中的意义。方法107例手术证实为陈旧性前十字韧带损伤患者,术前均行前抽屉试验、Lachman试验、轴移试验和MR检查。术后计算各项检查的敏感性,并分析产生假阴性的原因。结果前抽屉试验的阳性率为78.5%,Lachman试验为97.2%,轴移试验为91.6%,而MRI敏感性为93.5%。10例患者的关节镜检查显示前十字韧带近侧撕裂端再附着于后十字韧带。在此10例中,前抽屉试验的阳性率为60%,Lachman试验为80%,轴移试验为60%,而MRI敏感性为40%。本组9例轴移试验假阴性的患者中,有4例为撕裂的前十字韧带再附着于后十字韧带而替代了部分前十字韧带的功能,因此关节镜下显示胫骨外侧髁半脱位受限。2例Lachman试验假阴性的患者经关节镜证实为前十字韧带断端再附着伴有半月板桶柄样撕裂。在10例再附着患者中有3例MRI表现为韧带倾斜度变化。结论Lachman试验对诊断陈旧性前十字韧带损伤敏感性最高。MRI和轴移试验较敏感,但结果受MR检查技术和伴发损伤等诸多因素的影响。     

Kombinierte Verletzung von vorderem Kreuzband und medialem Seitenband des Kniegelenks—Zwei-bis Sechs-Jahres-Ergebnisse der operativen Behandlung

A retrospective study of 148 combined acute knee injuries with anterior cruciate and medial collateral ligament injuries was performed. Follow-up included 115 patients, 95 of whom were personally examined two to six years postoperatively. Proximal anterior cruciate ligament ruptures were treated with reinsertion in 96 patients, in case of intraligamentous lesions (44 times), augmentation with the semitendinosus tendon was performed. Medial collateral ligament lesions were explored during the operation. Reconstruction of intraligamentous ruptures was performed with sutures (120 times). Distal lesions were refixed with Burri plate or staple. A modified Ellison procedure was routinely performed. Postoperative treatment was cast-free and included immediate physiotherapy using a functional brace. Between the two groups with anterior cruciate ligament reinsertion and augmentation, no significant differences were observed in subjective evaluation (Lysholm score 85 vs. 88), activity level (Tegner score 5.5 vs. 5.4) or anterior stability (KT 1000 at 89 N 6.6 vs. 6.1 mm displacement). A clear pivot shift sign was noted in two knees with reinsertion and in none of the augmented group. Medial stability was reestablished almost completely, independent of the site of lesion or the reconstruction technique (average valgus movement at 30° flexion 0.7+vs. 0.5+on injured/contralateral side). We conclude that reinsertion of femoral anterior cruciate ligament ruptures will reestablish anterior stability in most cases, although semitendinosus augmentation appears to give slightly more reliable results. Medial stability is gained by site-depending reconstruction techniques. Whether intraligamentous medial collateral ligament lesions can be left alone with only the anterior cruciate ligament being reconstructed, cannot be answered by this study.     

The anterior cruciate ligament. A functional analysis based on postmortem studies.

In forty fresh human cadaver knees the function of the anterior cruciate ligament and of its two component parts, the posterolateral part and the anteromedial band, were studied by cutting these ligaments and others in different sequences and combinations and then manually stressing the knees. The anterior drawer sign cannot be obtained unless the anteromedial band is severed. The postolateral part and the medial collateral ligament are, respectively, the secondary and tertiary restraints limiting the anterior drawer sign. Both internal and external rotation are limited by the anterior cruciate ligament, especially when the knee is in extension. The anterior cruciate ligament also limits hyperextension.     

Replacement of the anterior cruciate ligament combined with valgization osteotomy of the tibia in incipient medial gonarthrosis with anterior cruciate ligament insufficiency

In 7 patients with chronic, primarily anteromedial instability and incipient medial gonarthrosis a procedure combining valgization osteotomy of the tibia with anterior cruciate ligament replacement was employed. Postoperative examinations after observation periods of between 6 months and 5 years revealed that the results were good to very good, both subjectively and objectively. There was either no recurrence or a definite alleviation of knee joint pain present preoperatively. In view of the good results the authors now regard a combination of valgization osteotomy and anterior cruciate ligament replacement as the treatment of choice in cases with clear insufficiency of the anterior cruciate ligament and simultaneous incipient medial gonarthrosis. The combined procedure improves chances of achieving the goal of therapy. A valgization osteotomy or an anterior cruciate ligament replacement alone ought to be regarded as inadequate treatment in such cases, especially in the longer term.     

Medical restraints to anterior-posterior motion of the knee

We investigated the motion of cadaver knees before and after section of the medial structures and anterior cruciate ligament. The knees were tested using a 5-degrees-of-freedom in vitro knee-testing apparatus that measured anterior-posterior, medial-lateral, and axial displacement as well as internal-external and valgus-varus rotation. The flexion angle could be varied but was fixed for each individual test. A 125-newton anterior-posterior force was applied perpendicular to the tibial shaft and the resulting motion of the knee was measured. In five knees the anterior cruciate ligament was cut first, followed by progressive cuts of the structures on the medial side (superficial medial collateral ligament, deep medial ligament, oblique fibers of the superficial medial ligament, and the posteromedial part of the capsule). Conversely, in five knees the medial structures were progressively cut first, followed by section of the anterior cruciate ligament. Tests were performed after each cut. With an intact anterior cruciate ligament, progressive cutting of the medial side had no effect on anterior and posterior displacements. When section of the medial structures followed cutting of the anterior cruciate ligament, anterior displacement exceeded that seen after isolated section of the anterior cruciate ligament. The anterior and posterior load-tests were repeated with the tibia fixed in 5 degrees of internal and 5 degrees of external rotation. Fixed external rotation had no effect on anterior and posterior displacements. Fixed internal rotation significantly decreased anterior displacement only when both the anterior cruciate ligament and the medial structures were cut.(ABSTRACT TRUNCATED AT 250 WORDS)     

The course of differently treated isolated ruptures of the anterior cruciate ligament as observed by prospective stress radiography

In a prospective stress radiographic study of the course of 21 isolated anterior cruciate ligament (ACL) injuries, primary suture was performed in eight patients and reconstruction due to chronic instability was performed in six patients. Seven patients were treated by exploratory arthrotomy only. After a follow-up period of seven years the anterior drawer sign had disappeared in five of the 14 patients who had shown this sign prior to operation, but in some of these patients progressive rotatory instabilities developed, so that the total abnormal instability did not improve in any of the three therapeutic groups. Only ten patients obtained a completely symptom-free knee. A well performed Jones procedure could reduce a chronic anterior drawer instability, but in several of the patients troublesome patellofemoral pain developed later. Acute suture of isolated anterior cruciate ligament injuries afforded the best results in this series and is recommended.     

Early results of the Leeds-Keio anterior cruciate ligament replacement.

We report the two- to four-year results following the insertion of the Leeds-Keio prosthetic ligament for chronic anterior cruciate deficiency. Virtually all the 20 patients were less disabled by instability, but objective results were good or excellent in only two-thirds and under anaesthesia the pivot shift sign was still positive in half. Arthroscopic and histological assessment in 16 patients failed to show the development of a functional neoligament, and the common appearance of a synovitic reaction to polyester particles gave concern.     

Early expression of marker genes in the rabbit medial collateral and anterior cruciate ligaments: the use of different viral vectors and the effects of injury.

Gene therapy is a technique that may offer advantages over current methods of cytokine delivery to ligaments. To determine if implanted genes could be expressed in normal and injured knee ligaments, the medial collateral ligament and anterior cruciate ligament were studied in 18 rabbits. A retroviral ex vivo technique using allograft medial collateral ligament and anterior cruciate ligament fibroblasts and an adenoviral in vivo technique were compared as methods for delivering the LacZ marker gene to knee ligaments. Bilateral knee surgeries were performed, and the rabbits were equally divided into three groups. Group 1 received the retrovirus and the medial collateral ligament was ruptured, Group 2 received the adenovirus and the medial collateral ligament was ruptured, and Group 3 received the adenovirus and the medial collateral ligament was not injured. The anterior cruciate ligament was not injured in any group. The medial collateral and anterior cruciate ligaments of the right knees received 10(6) allografted, transduced ligament fibroblasts or 10(9) adenovirus particles, whereas the ligaments of the left knee received a similar volume of saline solution only. Equal numbers of rabbits were killed at 10 days, 3 weeks, and 6 weeks following the procedure. Ligament samples were stained with X-gal to detect the expression of the LacZ gene product, beta-galactosidase. LacZ gene expression was evident in ruptured and uninjured medial collateral ligaments as well as in the anterior cruciate ligament. The expression lasted between 10 days and 3 weeks in the medial collateral and anterior cruciate ligaments with use of the retrovirus and between 3 and 6 weeks in the medial collateral ligament and at least 6 weeks in the anterior cruciate ligament with the adenovirus. The length of gene expression in the ruptured and uninjured medial collateral ligaments did not differ. These preliminary studies indicate that gene transfer to normal and injured knee ligaments is possible.     

Combined anterior cruciate reconstruction and Oxford unicompartmental knee arthroplasty

The options for treatment of the young active patient with isolated symptomatic osteoarthritis of the medial compartment and pre-existing deficiency of the anterior cruciate ligament are limited. The potential longevity of the implant and levels of activity of the patient may preclude total knee replacement, and tibial osteotomy and unicompartmental knee arthroplasty are unreliable because of the ligamentous instability. Unicompartmental knee arthroplasties tend to fail because of wear or tibial loosening resulting from eccentric loading. Therefore, we combined reconstruction of the anterior cruciate ligament with unicompartmental arthroplasty of the knee in 15 patients (ACLR group), and matched them with 15 patients who had undergone Oxford unicompartmental knee arthroplasty with an intact anterior cruciate ligament (ACLI group). The clinical and radiological data at a minimum of 2.5 years were compared for both groups. The groups were well matched for age, gender and length of follow-up and had no significant differences in their pre-operative scores. At the last follow-up, the mean outcome scores for both the ACLR and ACLI groups were high (Oxford knee scores of 46 (37 to 48) and 43 (38 to 46), respectively, objective Knee Society scores of 99 (95 to 100) and 94 (82 to 100), and functional Knee Society scores of 96 and 96 (both 85 to 100). One patient in the ACLR group needed revision to a total knee replacement because of infection. No patient in either group had radiological evidence of component loosening. The radiological study showed no difference in the pattern of tibial loading between the groups. The short-term clinical results of combined anterior cruciate ligament reconstruction and unicompartmental knee arthroplasty are excellent. The previous shortcomings of unicompartmental knee arthroplasty in the presence of deficiency of the anterior cruciate ligament appear to have been addressed with the combined procedure. This operation seems to be a viable treatment option for young active patients with symptomatic arthritis of the medial compartment, in whom the anterior cruciate ligament has been ruptured.     

陈旧性前交叉韧带损伤诊治分析

[目的]探讨临床检查和MRI诊断陈旧性前交叉韧带（anterior cruciate ligament，ACL）损伤的价值。[方法]回顾分析65例陈旧性ACL损伤患者的诊治经过，进行临床检查，其中8例行MRI检查，最后关节镜手术确诊。[结果]53例ACL完全损伤，前抽屉试验、Lachman试验和轴移试验的准确性分别为：79．2％、96．2％和92．5％；12例ACL部分损伤，前抽屉试验、Lachman试验和轴移试验的准确性分别为：16．7％、50．0％和33．3％。MRI诊断ACL损伤的准确性为100％。[结论]临床检查和MRI是诊断陈旧性ACL损伤的有效方法。     

Primary knee ligament repair--revisited

There were 4710 knee sprains resulting from skiing in the four Aspen ski areas between 1976 and 1979. Twenty percent of the patients (942) had complete tears. Of these, 302 elected to remain in Aspen for treatment. All were treated by primary ligament repair without augmentation. These cases were evaluated an average of 42 months after injury. Patients with isolated tears of the medial collateral ligament were found to be doing well; virtually all of them had returned to preinjury activity levels. Thirty-six percent of the isolated anterior cruciate repairs were rated failures, and 43% of the combination ACL-MCL injuries had failed because of anterior cruciate deficiency. Twenty-nine percent of the ACL and ACL-MCL injuries had meniscal tears. Cases that included meniscectomy had a failure rate twice as great as those in which the meniscus was preserved. The results following repair of anterior cruciate tears were not acceptable, and augmentation was indicated. Primary repair of medial collateral ligament tears produced excellent results. Meniscal tears were frequent in association with ligament disruption. Ligament repairs were less satisfactory when meniscectomy was performed at the time of the repair.     

内侧副韧带Ⅱ度损伤保守或手术修复对前交叉韧带重建后膝关节前后稳定性的影响

目的 探讨Ⅱ度内侧副韧带（MCL）损伤手术或保守治疗对前交叉韧带（ACL）重建前后稳定性的影响.方法 以54例膝关节ACL合并急性Ⅱ度MCL损伤患者为研究对象,所有患者受伤时间均〈1周,术前MRI检查示ACL连续性中断,MCL股骨、胫骨止点高信号,术前查体示前抽屉试验阳性,0°外翻应力试验阴性,30°外翻应力试验阳性.对所有患者术前行KT1000测量胫骨相对股骨前移度,膝关节活动度（ROM）,IKDC主观评分.将所有患者随机分为A、B两组,对A组患者采取关节镜下ACL异体单束重建＋MCL切开修复术;B组行单纯ACL异体单束重建,MCL采取支具固定保守治疗6周.术后1年对所有患者行IKDC评分、ROM测量、KT1000评价临床效果.结果 所有患者术后1年IKDC评分、KT 1000测量较术前均有统计学差异 （ t=13.699,9.553;P〈0.05）;A组患者IKDC主观评分与B组比较结果无统计学差异（2=6.273,P〉0.05）,两组患者术前术后关节活动度无统计学差异（t=0.672,P〉0.05）,A组患者术后膝关节前后稳定性改善（KT 1000测量值）较B组明显改善,且结果比较有统计学意义（t=0.932,P〈0.05）.结论 膝关节Ⅱ度MCL损伤合并ACL损伤建议MCL修复＋ACL重建一期手术完成.     

Therapeutische Möglichkeiten bei veralteten medialen Instabilitäten am Kniegelenk

Especially Grade II and III of chronic anteromedial rotatory instability of the knee should be treated by static and dynamic extraarticular procedures of the medial compartment. For the treatment of deficient anterior cruciate ligament we advise intra-articular replacement with a medial strip of the patella tendon, otherwise we expect meniscal degeneration, osteoarthritis and progressive instability. In patients with considerable instability and in young persons in addition to the cruciate ligament repair a distal iliotibial-band transfer is recommended to avoid attenuation of intra-intraarticular and capsular ligaments.     

Differential expression of integrin subunits in canine knee ligament fibroblasts.

A method for measuring the expression of integrin subunits on the cell surface of knee ligament fibroblasts was developed with use of flow cytometry and immunofluorescence. The ligament cells exhibited uniform size and density, as shown by forward and side-scatter properties, and showed minimal nonspecific binding of isotype control antibodies compared with unstained cells. All cells expressed the alpha5 integrin subunit; lateral collateral ligament cells stained with antibody to alpha5 showed a mean fluorescence intensity 2-fold higher than that of medial collateral ligament cells, 1.5-fold higher than that of posterior cruciate ligament cells, and 3-fold higher than that of anterior cruciate ligament cells, indicating a greater expression of the alpha5 subunit by lateral collateral ligament cells than by medial collateral, posterior cruciate, and anterior cruciate ligament cells. All cells expressed the beta1 integrin subunit; the expression by posterior cruciate ligament cells was 3-fold higher than that by medial collateral ligament or lateral collateral ligament cells and 5-fold higher than that by anterior cruciate ligament cells. All cells expressed the beta3 integrin subunit; the expression by posterior cruciate ligament cells was 1.5, 3, and 4.5-fold greater than that by lateral collateral, anterior cruciate, and medial collateral ligament cells, respectively. Our data suggest there is a differential expression of integrin subunits in knee ligament fibroblasts, and this in part may explain differences in their attachment and adherence to extracellular matrix molecules.     

内侧副韧带Ⅱ度损伤保守或手术修复对前交叉韧带重建后膝关节前后稳定性的影响

目的 探讨Ⅱ度内侧副韧带（MCL）损伤手术或保守治疗对前交叉韧带（ACL）重建前后稳定性的影响.方法 以54例膝关节ACL合并急性Ⅱ度MCL损伤患者为研究对象,所有患者受伤时间均〈1周,术前MRI检查示ACL连续性中断,MCL股骨、胫骨止点高信号,术前查体示前抽屉试验阳性,0°外翻应力试验阴性,30°外翻应力试验阳性.对所有患者术前行KT1000测量胫骨相对股骨前移度,膝关节活动度（ROM）,IKDC主观评分.将所有患者随机分为A、B两组,对A组患者采取关节镜下ACL异体单束重建＋MCL切开修复术;B组行单纯ACL异体单束重建,MCL采取支具固定保守治疗6周.术后1年对所有患者行IKDC评分、ROM测量、KT1000评价临床效果.结果 所有患者术后1年IKDC评分、KT 1000测量较术前均有统计学差异 （ t=13.699,9.553;P〈0.05）;A组患者IKDC主观评分与B组比较结果无统计学差异（2=6.273,P〉0.05）,两组患者术前术后关节活动度无统计学差异（t=0.672,P〉0.05）,A组患者术后膝关节前后稳定性改善（KT 1000测量值）较B组明显改善,且结果比较有统计学意义（t=0.932,P〈0.05）.结论 膝关节Ⅱ度MCL损伤合并ACL损伤建议MCL修复＋ACL重建一期手术完成.     

Die Rekonstruktion des medialen patellofemoralen Ligaments mit der getunnelten Semitendinosussehne

OBJECTIVE: Stabilization of the patella by reconstruction of the medial patellofemoral ligament. INDICATIONS: Chronic recurrent lateral dislocation or subluxation of the patella. Habitual lateral dislocation of the patella. CONTRAINDICATIONS: Primary dislocation of the patella. Genu valgum with a Q-angle > 15 degrees . Status following semitendinosus tendon transfer to reconstruct the anterior cruciate ligament. Joint infection. Neurogenic instability, ischiocrural muscle deficiency. SURGICAL TECHNIQUE: Division of the distal insertion of the semitendinosus muscle at the pes anserinus. Subligamentous tunneling at the proximal insertion of the medial collateral ligament. The distal end of the semitendinosus tendon is transferred through the subligamentous tunnel to the medial patellar margin. Fixation of the tendon to the medioproximal patellar margin by passing it through an oblique transpatellar drill hole. RESULTS: The patella was stabilized by dynamic reconstruction of the medial patellofemoral ligament in 14 patients with chronic recurrent or habitual lateral patellar dislocation. Ten patients were available for clinical follow-up assessment at an average of 13 months (8-27 months) postoperatively. The postoperative Kujala Index (maximum 100 points) increased on average from 56 to 95 points.     

The effect of section of the medial collateral ligament on force generated in the anterior cruciate ligament

Ten fresh-frozen knees from cadavera were instrumented with a specially designed transducer that measures the force that the anterior cruciate ligament exerts on its tibial attachment. Specimens were subjected to tibial torque, anterior tibial force, and varus-valgus bending moment at selected angles of flexion of the knee ranging from 0 to 45 degrees. Section of the medial collateral ligament did not change the force generated in the anterior cruciate ligament by applied varus moment. When valgus moment was applied to the knee, force increased dramatically after section of the medial collateral ligament; the increases were greatest at 45 degrees of flexion. Section of the medial collateral ligament had variable effects on the force generated in the anterior cruciate ligament during internal rotation but dramatically increased that generated during external rotation; these increases were greatest at 45 degrees. Section of the medial collateral ligament increased mean total torsional laxity by 13 degrees (at 0 degrees of flexion) to 20 degrees (at 45 degrees of flexion). Application of an anteriorly directed force to the tibia of an intact knee increased the force generated in the anterior cruciate ligament; this increase was maximum near the mid-part of the range of tibial rotation and minimum with external rotation of the tibia. Section of the medial collateral ligament did not change the force generated in the anterior cruciate ligament by straight anterior tibial pull near the mid-part of the range of tibial rotation.(ABSTRACT TRUNCATED AT 250 WORDS)