Active knee motion after cruciate ligament rupture. Stereoradiography

In 10 patients with an old injury of the anterior cruciate ligament, the three-dimensional movements of the knee joint were studied when the patients flexed their knees. Tibial motions were recorded using roentgen stereophotogrammetric analysis. Internal rotation and adduction of the tibia were reduced in the injured knees when compared with the intact knees; during flexion of the knee joint, the tibial intercondylar eminence occupied a more lateral and posterior position on the injured side. Our results may indicate that the knee joint is continuously exposed to abnormal stresses when the anterior cruciate ligament is torn.     

Gait analysis 6 and 12 months after anterior cruciate ligament reconstruction surgery

Little is known about knee function after anterior cruciate ligament reconstruction in the vital activities of walking and stair use. Gait analysis was done on patients 6 months (n = 8) and 12 months (n = 9) after reconstruction of the anterior cruciate ligament. Paired t tests were used to compare the injured and uninjured knees. During level walking, the patients placed external flexion torques on their injured knees throughout midstance, indicating the absence of quadriceps avoidance gait. The peak external flexion torque (resisted by the knee extensor muscles) placed on the injured knee was significantly less than that of the uninjured knee when ascending stairs (at 12 months, 68.4 and 85.3 N-m in the injured and uninjured knees, respectively) and also when descending stairs (at 12 months, 70.8 and 81.7 N-m in the injured and uninjured knees, respectively). The injured knee produced significantly less power than the uninjured knee when ascending stairs, but this difference was not significant when descending stairs. These findings indicate that asymmetric gait patterns persisted up to 1 year after surgical reconstruction and were more pronounced during stair ascent and descent than in level walking. These results indicate that clinicians should include specific interventions targeted at improving knee function during stair use to restore normal function after anterior cruciate ligament reconstruction.     

Three-dimensional instability of the anterior cruciate deficient knee

Using roentgen stereophotogrammetry we have recorded the three-dimensional movements of the knee during an anteroposterior laxity test in 36 patients with torn anterior cruciate ligaments and in three cadaver knees. At 30 degrees of knee flexion and before loads were applied the tibia occupied a more laterally rotated position if the anterior cruciate ligament had been injured. When the tibia was pulled anteriorly knees with cruciate deficiency rotated more laterally and were more abducted than normal knees. Posterior traction induced lateral rotation in the injured knee and medial rotation in the intact one. Precise knowledge of the three-dimensional instability of the anterior cruciate deficient knee may be important when the laxity is evaluated only in relation to one of the three cardinal axes.     

Kinematics after tear in the anterior cruciate ligament: dynamic bilateral radiostereometric studies in 11 patients

We studied the kinematics of both knees using radiostereometry in 11 patients with unilateral injury of the anterior cruciate ligament and normal contralateral knee. Continuous radiostereometric exposures at a speed of 24 exposures a second were performed, when the patients ascended an 8 cm high platform. The tibial center was more dorsally displaced and the tibia more externally rotated on the injured side. This increasing external tibial rotation was associated with increased anterior displacement of the lateral femoral condyle. The latter also displayed less anterior-posterior translations during continuous extension. The anterior-posterior translation of the medial condyle was about the same as on the uninjured side. Changes in the kinematics of the knee joint due to rupture of the anterior cruciate ligament can result in an abnormal joint load, which may increase the risk of damage to the cartilage and the menisci.     

Kinematics after tear in the anterior cruciate ligament: Dynamic bilateral radiostereometric studies in 11 patients

We studied the kinematics of both knees using radiostereometry in 11 patients with unilateral injury of the anterior cruciate ligament and normal contralateral knee. Continuous radiostereometric exposures at a speed of 2-4 exposures a second were performed, when the patients ascended an 8 cm high platform. The tibial center was more dorsally displaced and the tibia more externally rotated on the injured side. This increasing external tibial rotation was associated with increased anterior displacement of the lateral femoral condyle. The latter also displayed less anterior-posterior translations during continuous extension. The anterior-posterior translation of the medial condyle was about the same as on the uninjured side. Changes in the kinematics of the knee joint due to rupture of the anterior cruciate ligament can result in an abnormal joint load, which may increase the risk of damage to the cartilage and the menisci.     

Kinematics after tear in the anterior cruciate ligament: Dynamic bilateral radiostereometric studies in 11 patients

We studied the kinematics of both knees using radiostereometry in 11 patients with unilateral injury of the anterior cruciate ligament and normal contralateral knee. Continuous radiostereometric exposures at a speed of 2-4 exposures a second were performed, when the patients ascended an 8 cm high platform. The tibial center was more dorsally displaced and the tibia more externally rotated on the injured side. This increasing external tibial rotation was associated with increased anterior displacement of the lateral femoral condyle. The latter also displayed less anterior-posterior translations during continuous extension. The anterior-posterior translation of the medial condyle was about the same as on the uninjured side. Changes in the kinematics of the knee joint due to rupture of the anterior cruciate ligament can result in an abnormal joint load, which may increase the risk of damage to the cartilage and the menisci.     

A biomechanical evaluation of the Lenox Hill knee brace

This study was conducted to determine the effectiveness of the Lenox Hill knee brace in limiting anterior translation and external rotation of the tibia in reference to the femur in normal and ligament-deficient knees. Four fresh cadaver knees were fitted with Lenox Hill knee braces according to the manufacturer's guidelines. A computer-assisted testing apparatus was constructed that allowed each knee to be tested as a function of knee flexion angle, joint load, and soft tissue integrity. Each knee served as its own control. While 45 kg of anterior force was applied to the tibia of the anterior cruciate ligament deficient knees, the Lenox Hill knee brace was able to decrease anterior translation from an average of 10 mm, to 5.7 mm, at 30 degrees of flexion when no vertical load was present. This limiting effect was lost when the medial collateral ligament was sectioned in addition to the anterior cruciate ligament or when both the medial and the lateral collateral ligaments were sectioned along with the anterior cruciate ligament. When 20 Newton-meters (Nm) of torque was applied to the femurs at 30 degrees of flexion without vertical load, the Lenox Hill knee brace limited external rotation of the tibia in all tested categories. For intact knees at 30 degrees of flexion and no vertical load, the Lenox Hill knee brace decreased external rotation from 18 degrees to 10 degrees. In the anterior cruciate ligament-sectioned knees, external rotation was decreased from an average of 20.2 degrees to 16.1 degrees. In the knees with sectioned anterior cruciate and medial collateral ligaments, the average reduction was from 21.2 degrees to 15.4 degrees.(ABSTRACT TRUNCATED AT 250 WORDS)     

Surgical or non-surgical treatment of acute rupture of the anterior cruciate ligament. A randomized study with long-term follow-up

One hundred and eleven consecutive patients who had acute injuries to the knee that included rupture of the anterior cruciate ligament, as shown by physical examination with the patient under anesthesia and by diagnostic arthroscopy, were randomized to three treatment groups: simple repair of all injured structures, repair of all injured structures and augmentation of the anterior cruciate ligament with a strip of the iliotibial band, and repair of all injured structures except the anterior cruciate ligament. In all other respects, the knees were treated in an identical fashion. Of the 111 patients, 107 were re-examined forty-five months or more after operation. At the most recent follow-up, the knees that had been treated by repair and augmentation of the anterior cruciate ligament were significantly more stable and had had significantly fewer subsequent meniscal tears. Sufficient instability to necessitate late reconstruction was also less frequent in the patients who had had an augmented repair. These patients had better function of the knee and a higher level of activity than the patients in the other two groups. Sixty-four per cent of these patients who had a rupture of the anterior cruciate also had a meniscal tear, and primary care was indicated for more than 50 per cent of the tears. Therefore, we believe that early arthroscopic examination is essential for patients who have an acute rupture of the anterior cruciate ligament.     

Knee dislocations: where are the lesions? A prospective evaluation of surgical findings in 63 cases

OBJECTIVE: To evaluate soft-tissue injury patterns in a large series of patients with knee dislocations to identify frequency and associations that may aid in surgical planning. DESIGN: Prospective clinical study. SETTING: Two institutions, both level I trauma centers. PATIENTS: Sixty patients with 63 dislocatable knees. RESULTS: Cause of injury was motor vehicle injury in 34 patients, sports in 23 patients, and falls in 3 patients; 71% of knees studied had bicruciate injuries. Eight knees had associated major intraarticular fractures. Vascular disruption occurred in 14% of knees. Peroneal nerve palsies occurred in 14% of knees. All injured knees with complete peroneal nerve palsies had anterior cruciate ligament, posterior cruciate ligament, and lateral collateral ligament disruptions. The incidence of vascular injury was the same for patients injured in sports as for those injured in road trauma. Reattachable ligamentous avulsions occurred in 19% for anterior cruciate ligament, 51% for posterior cruciate ligament, 64% for medial collateral ligament, and 84% for lateral collateral ligament injuries. Certain injury patterns also had a high association of tendon and capsule avulsions. Proximal lateral collateral ligament injuries were commonly associated with popliteus tendon avulsions and seldom with distal biceps avulsions. Distal lateral collateral ligament injuries were commonly associated with distal biceps avulsions and seldom with popliteus tendon avulsions. Reattachable meniscal capsular avulsions off the tibia occurred predominantly when the collateral ligament injury was a distal avulsion. CONCLUSIONS: This study showed a wide variety of injury patterns. Knees had to have at least two ligaments injured to be dislocatable but not necessarily both cruciate ligaments. Sports injuries have the same pattern of injury as motor vehicle accidents, suggesting similar forces of injury. The study demonstrates a high incidence of reattachable avulsion injuries to ligaments and soft tissues in dislocatable knees. These may not be as easily dealt with if surgery is delayed beyond 3-4 weeks.     

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.     

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.     

Acute hemarthrosis of the knee: indications for diagnostic arthroscopy

The objective of this study was to define the role of early diagnostic knee arthroscopy for patients with an acute knee injury and hemarthrosis. Forty-five patients with an acute knee injury followed by a posttraumatic hemarthrosis during a 1-year period were prospectively reviewed. All patients were evaluated preoperatively followed by examination under anesthesia and arthroscopy of the knee. The majority of patients, 32 (71%), had an anterior cruciate ligament tear. Meniscal tears occurred in 21 patients (47%). Meniscal tears requiring surgery occurred in only 10 of 25 meniscal tears (40%). Seven patients (16%) had medial collateral ligament and/or posteromedial capsular sprain. Eight patients (18%) had an osteochondral fracture or patellar dislocation associated with an osteochondral fracture. The majority of knees with a torn meniscus or osteochondral fracture had an anterior cruciate ligament tear. Clinically, 18 of 21 knees (86%) with an acute complete anterior cruciate ligament tear were diagnosed preoperatively with the Lachman test. The Lachman test conducted with patients under anesthesia was positive for 19 of 21 knees (90%) with an acute complete anterior cruciate ligament tear. The preoperative examination correctly identified six of seven knees (86%) with a medial collateral ligament sprain. The preoperative Lachman test was positive in only two of five knees (40%) with a partial anterior cruciate ligament tear. The Lachman test with patients under anesthesia was positive for four of five knees (80%) with an acute partial anterior cruciate ligament tear. Preoperative examination yielded the correct diagnosis in only 9 of 21 knees (43%) with a meniscal tear and 1 of 6 knees (17%) with an osteochondral fracture.(ABSTRACT TRUNCATED AT 250 WORDS)     

Knee laxity in cruciate ligament injury: Value of examination under anesthesia

Arthrometry was performed before and during anesthesia in 41 patients with acute or old anterior cruciate ligament injuries and only minor signs of valgus or varus instability. The uninjured contralateral knee served as a control. The influence of anesthesia on the anterior stability was distinct in acute knee injuries. There was also a small, but definite, increase in anterior laxity in uninjured knees. Knees with old injuries were more lax, and the injured-uninjured difference in anterior laxity was more pronounced. Stability examination under anesthesia is of great value for acutely injured knees.     

Knee laxity in cruciate ligament injury. Value of examination under anesthesia

Arthrometry was performed before and during anesthesia in 41 patients with acute or old anterior cruciate ligament injuries and only minor signs of valgus or varus instability. The uninjured contralateral knee served as a control. The influence of anesthesia on the anterior stability was distinct in acute knee injuries. There was also a small, but definite, increase in anterior laxity in uninjured knees. Knees with old injuries were more lax, and the injured-uninjured difference in anterior laxity was more pronounced. Stability examination under anesthesia is of great value for acutely injured knees.     

Congenital absence of the anterior cruciate ligament. A common component of knee dysplasia

The clinical and radiological features of 12 knees (10 patients) with congenital absence of the anterior cruciate ligament are presented. The high frequency of this condition in association with other more easily recognised congenital abnormalities of the knee is discussed. It is concluded that congenital absence of the anterior cruciate ligament is more common than generally suspected and is associated with other developmental abnormalities of both bone and soft tissue in the lower limb, particularly around the knee joint.     

Two-stage reconstruction with autografts for knee dislocations

Traumatic knee dislocations are severe injuries that involve damage to the anterior cruciate ligament, the posterior cruciate ligament, and the lateral or medial ligamentous structures. There are no established methods of treatment. The objective of the current study was to report the clinical outcome of a two-stage autologous reconstruction on nine knees (eight patients). The mean followup was 40.1 months. The first stage of the reconstruction was done at a mean of 2 weeks after the injury, and the posterior cruciate ligament was reconstructed by an arthroscopically assisted technique using contralateral autogenous hamstring tendon as the graft material. Three months later, the second stage of the reconstruction was done for the ligaments that had not healed with conservative treatment. Arthroscopically assisted anterior cruciate ligament reconstruction was done on all of the knees using the ipsilateral autogenous hamstring tendon or bone-patellar tendon-bone as the graft material. At the same time, a medial collateral ligament reconstruction using an autogenous semitendinosus tendon was done on one knee, and reconstruction of the posterolateral ligamentous structures using a biceps tendon was done on three knees. Each of the knees that was reconstructed was capable of full extension, and the mean degree of passive flexion was 139.5 degrees +/- 5.2 degrees. The mean side-to-side difference in anteroposterior total laxity (KT-1000 arthrometer, manual maximum) was 2.3 +/- 1.9 mm. None of the knees had lateral or medial instability. All of the injured ligaments were able to be reconstructed with autografts, and severe contracture was able to be prevented. A good clinical outcome can be achieved when two-stage reconstruction is used for traumatic knee dislocations.     

Incidence and mechanism of the pivot shift. An in vitro study.

The aim of this study was to determine the incidence and mechanism of the pivot shift phenomenon in the normal and anterior cruciate ligament transected knee in vitro. Fifteen knees were tested under a range of valgus moments and iliotibial tract tensions when intact and after anterior cruciate ligament transection. Knee kinematics were measured and described in terms of tibial rotation as the knee flexed. Eight knees pivoted after anterior cruciate ligament transection. The mean pivot shift motion was an external tibial rotation of 17 degrees (+/- 11 degrees standard deviation) over a range of 27 degrees (+/- 24 degrees) knee flexion, at a mean flexion angle of 56 degrees (+/- 27 degrees). Clinically, this corresponds to a reduction of an anteriorly subluxed lateral tibial plateau as the knee flexes. When intact, pivoting and nonpivoting knees had similar anteroposterior laxity, but after anterior cruciate ligament transection, the pivoting group had significantly greater laxity. The loading required to elicit the pivot shift was critical and variable between knees, which raises questions about comparing clinicians' techniques and results in assessing the buckling instability attributable to anterior cruciate ligament injury.     

髌腱复合体重建创伤性前后交叉韧带

目的：为了评价髌腱复合体(带骨块的髌韧带，即骨—髌膜—骨)对前后交叉韧带断裂后重建的手术疗效。方法：1995—2001年，收治32例前后交叉韧带损伤的患者给予髌腱复合体重建术。结果：所有病人患膝关节稳定性明显增强，术后抽屉试验全部阴性。结论：带骨块的髌韧带具有强抗牵拉力，固定可靠，等长重建，功能改善明显等优点。髌膜复合体是理想的前后交叉韧带替代材料。     

Arthroscopy in acute injuries of anterior cruciate-deficient knees: fresh and old intraarticular lesions

Sixty-four patients out of a much larger population who presented within 2 weeks of an acute injury to the knee were found at arthroscopy to have either a chronic tear or chronic incompetent anterior cruciate ligament (group I, 32 patients) or to have an acutely torn anterior cruciate ligament (ACL) (group II, 32 patients). Arthroscopy of both groups allowed the author to compare and contrast the lesions found in each group. Chondromalacia of the femorotibial joint is significantly more frequent in chronic ACL-deficient knees (p less than 0.05), and there is a tendency to degenerative meniscus lesions and chondromalacia patella in these knees too.     

Intraoperative arthrometry in anterior cruciate ligament reconstruction

Arthrometry has an established role in the measurement of knee laxity in anterior cruciate ligament injury and following reconstruction. The role of routine intraoperative arthrometry in anterior cruciate ligament reconstruction is poorly defined, and this study was designed to test the hypothesis that intraoperative arthrometry provides an objective method of documenting successful knee stabilisation following anterior cruciate ligament reconstruction. A consecutive cohort of 100 patients with unilateral isolated anterior cruciate ligament disruption were prospectively evaluated using a Rolimeter arthrometer. A maximal manual force method was utilised by a single examiner. This allowed for side-to-side comparisons with the uninjured contralateral knee. Analysis of tibial translation was recorded preoperatively with patients both awake and asleep, intraoperatively following anterior cruciate ligament reconstruction, and postoperatively at 2 weeks and 3 months. Statistical analysis was performed using Spearman's correlation coefficients. Intraoperative arthrometry of anterior cruciate ligament reconstructed knees revealed statistically significant correlation with measurements of uninjured knees (p < 0.0001). These findings were reproducible at 2 weeks (p < 0.0001) and at 3 months (p = 0.0002). Based on our findings, we conclude that intraoperative arthrometry can be simple and provide reproducible results. It is a useful method of immediately and objectively documenting successful anterior cruciate ligament reconstruction.