Partial Anterior Cruciate Ligament Rupture Research Articles

Evaluation of anterior cruciate ligament ruptures by three dimension MR imaging

Objective To compare the diagnosic performance of conventional 2D and 3D Cube MR imaging to identify complete and partial tears of anterior cruciate ligament(ACL).Methods Farty patients suspected of having tears of anterior cruciate ligament were prospectively studied by 3.0 T conventional 2D and 3D Cube MR imaging and arthroscopy.MR images were interpreted in consensus by two experienced radiologists,and the ACL was diagnosed as being normal,partially torn,or completely torn.Diagnostic accuracy of 2D and 3D Cube MR for the detection of both complete and partial tears of ACL was calculated using arthroscopy as the standard of reference.Area under curve (AUC) of both methods were calculated using ROC curves and were compared using Hanley& McNeil curve comparisions.Results Sixteen patients had intact ACL,12 had complete tear,and 12 had partial tear of the ACL at arthroscopy.For complete ACL tear,AUC of 2D MR and 3D Cube was 0.839 and 0.923 respectively,and there was no significant difference on ROC curves (Z =1.245,P =0.213).For partial ACL tears,AUC of 2D and 3D Cube MR were 0.643 and 0.881 respectively,and there was significant difference on ROC curves (Z =2.384,P =0.017).Conclusions Both 2D MR and 3D Cube MR have high sensitivity and specificity for identifying the complete ruptures of ACL.3D Cube MRI appears to be superior inidentifying partial rupture of ACL. Key words: Anterior cruciate ligament; Lacerations; Magnetic resonance imaging

Clinically Relevant Injury Patterns After an Anterior Cruciate Ligament Injury Provide Insight Into Injury Mechanisms

Background: The functional disability and high costs of treating anterior cruciate ligament (ACL) injuries have generated a great deal of interest in understanding the mechanism of noncontact ACL injuries. Secondary bone bruises have been reported in over 80% of partial and complete ACL ruptures. Purpose: The objectives of this study were (1) to quantify ACL strain under a range of physiologically relevant loading conditions and (2) to evaluate soft tissue and bony injury patterns associated with applied loading conditions thought to be responsible for many noncontact ACL injuries. Study Design: Controlled laboratory study. Methods: Seventeen cadaveric legs (age, 45 ± 7 years; 9 female and 8 male) were tested utilizing a custom-designed drop stand to simulate landing. Specimens were randomly assigned between 2 loading groups that evaluated ACL strain under either knee abduction or internal tibial rotation moments. In each group, combinations of anterior tibial shear force, and knee abduction and internal tibial rotation moments under axial impact loading were applied sequentially until failure. Specimens were tested at 25° of flexion under simulated 1200-N quadriceps and 800-N hamstring loads. A differential variable reluctance transducer was used to calculate ACL strain across the anteromedial bundle. A general linear model was used to compare peak ACL strain at failure. Correlations between simulated knee injury patterns and loading conditions were evaluated by the χ2 test for independence. Results: Anterior cruciate ligament failure was generated in 15 of 17 specimens (88%). A clinically relevant distribution of failure patterns was observed including medial collateral ligament tears and damage to the menisci, cartilage, and subchondral bone. Only abduction significantly contributed to calculated peak ACL strain at failure (P = .002). While ACL disruption patterns were independent of the loading mechanism, tibial plateau injury patterns (locations) were significantly (P = .002) dependent on the applied loading conditions. Damage to the articular cartilage along with depression of the midlateral tibial plateau was primarily associated with knee abduction moments, while cartilage damage with depression of the posterolateral tibial plateau was primarily associated with internal tibial rotation moments. Conclusion: The current findings demonstrate the relationship between the location of the tibial plateau injury and ACL injury mechanisms. The resultant injury locations were similar to the clinically observed bone bruises across the tibial plateau during a noncontact ACL injury. These findings indicate that abduction combined with other modes of loading (multiplanar loading) may act to produce ACL injuries. Clinical Relevance: A better understanding of ACL injury mechanisms and associated risk factors may improve current preventive, surgical, and rehabilitation strategies and limit the risk of ACL and secondary injuries, which may in turn minimize the future development of posttraumatic osteoarthritis of the knee.

A comparison of Telos™ stress radiography versus Rolimeter™ in the diagnosis of different patterns of anterior cruciate ligament tears

Our knowledge on anterior cruciate ligament (ACL) pathomechanics has increased. The diagnosis of partial ACL tears must be accurate in order to adjust the operative planning to anatomic status and injury severity. Instrumented measurement of knee laxity is a useful preoperative tool to quantify anterior tibial translation and several laximetry tests are available. Yet, their accuracy remains to be established. Clinical examination combined to instrumented laximetry with Telos™ 15 kg and/or Rolimeter™ would increase their sensitivity and specificity in the diagnosis of various ACL injury patterns. One hundred and seventy-seven patients were prospectively included. The ACL status was validated by arthroscopy. Around 69.5% had a complete ACL tear and 30.5% had a partial ACL tear. Gross laxity with positive clinical tests was associated with complete ACL tears. Mean side-to-side difference was significantly greater with both laximetry methods in complete versus partial ACL tears. Laximetry results among different types of partial tears were not significantly different. Telos™ results were consistent with gross laxity confirmed by pivot-shift test, while this was not recorded with Rolimeter™. Gross laxity with clinical tests and anterior tibial translation more than 5mm with Telos™ were substantially associated with complete ACL tears. The combination of standard clinical examination with Telos™ was more accurate than with Rolimeter™ in the preoperative identification of the ACL injury pattern. Applying additional diagnostic tools can help the surgeon to preoperatively diagnose partial or complete ACL ruptures and propose an injury-specific surgical treatment. Level III (case-control study).

Impact of Partial and complete rupture of anterior cruciate ligament on medial meniscus: A cadavaric study.

Background:The clinical relationship between medial meniscus tear and anterior cruciate ligament (ACL) rupture has been well documented. However, the mechanism of this clinical phenomenon is not exactly explained. Our aim is to investigate the biomechanical impact of partial and complete ACL rupture on different parts of medial meniscus.Materials and Methods:Twelve fresh human cadaveric knee specimens were divided into four groups: ACL intact (ACL-I), anteromedial bundle transection (AMB-T), posterolateral bundle transection (PLB-T), and ACL complete transection (ACL-T) group. Strain on the anterior horn, body part, and posterior horn of medial meniscus were measured under 200 N axial compressive tibial load at 0°, 30°, 60°, and 90° of knee flexion, respectively.Results:Compared with the control group (ACL-I), the ACL-T group had a higher strain on whole medial meniscus at 0°, 60°, and 90° of flexion. But at 30°, it had a higher strain on posterior horn of meniscus only. As to PLB-T group, strain on whole meniscus increased at full extension, while strain increased on posterior horn at 30° and on body of meniscus at 60°. However, AMB-T only brought about higher strain at 60° of flexion on body and posterior horn of meniscus.Conclusions:Similar to complete rupture, partial rupture of ACL can also trigger strain concentration on medial meniscus, especially posterior horn, which may be a more critical reason for meniscus injury associated with chronic ACL deficiency.

Paper # 192: Therapeutic Advantage in Selective Ligament Augmentation for Partial Tears of Anterior Cruciate Ligament

Background: The selected anterior cruciate ligament (ACL) augmentation procedure, either anteromedial (AM) or posterolateral (PL), has been introduced as a treatment of choice for the repair of partial ACL ruptures which is based on the double bundle anatomy of the ACL. The preserved mechanoreceptor and vascularity in the remnant ACL is thought to provide neurological and biological benefits. Although enhanced knee joint proprioception in ACL augmented patients has been previously reported, there are no studies that assess the biological healing advantages of the graft after the ACL augmentation procedure. Hypothesis: Selected ACL augmentation for partial tears can promote the healing process of the grafted tendon and provide better biomechanical properties compared to ACL reconstruction of a complete tear. Study Design: Controlled Laboratory Study Methods: Two different ACL injury models were established in normal rats; 1) ACL augmentation of a partial tear model and 2) an ACL reconstruction of a complete tear model. To biologically assess the models, cell infiltration and angiogenesis in the grafted tendons were analyzed using hematoxylin/eosin staining and immunostaining using isolectin B4 respectively. Additionally, rat-specific type III collagen were evaluated by immunohistochemical staining to determine the extent of healing, while anti-rat neurofilament antigen was assessed to examine proprioceptive recovery. Biological assessments of the augmented and reconstructed grafts were conducted at week 2 postoperatively and biomechanical testing was performed at week 8 postoperatively. Results: A significantly greater number of infiltrating cells were observed in the augmented graft than in the reconstructed graft as was an increase in angiogenesis. There was also an increased amount of rat-specific type III collagen and anti-rat neurofilament antigen expressed in the augmented graft compared to the reconstructed graft. Biomechanical testing showed that failure load was significantly higher in the augmentation group compared with the reconstruction group. Conclusions: Selected ACL augmentation for partial tears could have biological benefits to promote the grafted tendon resulting in a better biomechanical healing when compared to complete ACL reconstruction. Paper # 193: 3-D CT Analysis of Tunnel Widening in ACL Reconstruction Using Allograft Tendons versus Hamstring Autografts STEVEN CLAES, MD, BELGIUM CEDRIC ROBBRECHT, MEDICAL STUDENT, BELGIUM PETER MAHIEU, MD, BELGIUM PETER VERDONK, MD, PHD, BELGIUM · University Hospitals Gent, Gent, BELGIUM Summary: Tunnel widening after ACL reconstruction is significantly increased with the use of allografts compared to autografts. Abstract: Objective: Tunnel widening has been described after ACL reconstruction and is explained by mechanical and biological phenomena. The aim of this study was to examine the feasibility of Computed Tomography 3D reconstructions to study tunnel widening after ACL surgery. Secondly, the goal was to examine differences in tunnel widening between allovs. autografts and between RCI vs. BioRCI among autografts. Material and Methods: Thirty-five patients underwent ACL reconstruction performed by a single surgeon (PV). A deep-frozen tibialis posterior tendon allograft was used in 10 patients, while in 25 patients both autologous semitendinosus and gracilis tendons were implanted. All grafts were fixed by a suspensory device on the femoral cortex (Endobutton, Smith&Nephew) and with a screw (BioRCI for allografts, RCI (n 12) or BioRCI (n 13) for autografts, Smith&Nephew) and staple on the tibia. The subjects were evaluated at a minimal follow-up of 1 year using a CT-based 3D reconstruction of both femoral and tibial tunnels. Tunnel widening was measured using a best-fit cylinder model by a least square criterium using the MIMICS software program (MIMICS v.13, Materialise, Belgium). Results: On the femoral side, tunnels were enlarged by 53% in the allograft group versus 35% for the autograft group. On the tibial side, tunnels were enlarged 48% in e199 ABSTRACTS Objective: Tunnel widening has been described after ACL reconstruction and is explained by mechanical and biological phenomena. The aim of this study was to examine the feasibility of Computed Tomography 3D reconstructions to study tunnel widening after ACL surgery. Secondly, the goal was to examine differences in tunnel widening between allovs. autografts and between RCI vs. BioRCI among autografts. Material and Methods: Thirty-five patients underwent ACL reconstruction performed by a single surgeon (PV). A deep-frozen tibialis posterior tendon allograft was used in 10 patients, while in 25 patients both autologous semitendinosus and gracilis tendons were implanted. All grafts were fixed by a suspensory device on the femoral cortex (Endobutton, Smith&Nephew) and with a screw (BioRCI for allografts, RCI (n 12) or BioRCI (n 13) for autografts, Smith&Nephew) and staple on the tibia. The subjects were evaluated at a minimal follow-up of 1 year using a CT-based 3D reconstruction of both femoral and tibial tunnels. Tunnel widening was measured using a best-fit cylinder model by a least square criterium using the MIMICS software program (MIMICS v.13, Materialise, Belgium). Results: On the femoral side, tunnels were enlarged by 53% in the allograft group versus 35% for the autograft group. On the tibial side, tunnels were enlarged 48% in e199 ABSTRACTS

Augmentation Procedure for Partial Rupture of the Anterior Cruciate Ligament

Arthroscopic examination before anterior cruciate ligament (ACL) reconstruction shows the presence of several types of ACL remnants within the intercondylar notch. It is thought that 10% to 20% of the ACL injury cases represent a partial rupture of the ACL. In these cases, although rupture of the anteromedial or posterolateral bundle can be seen, the other bundle is preserved with an attachment of the anatomical femoral origin. We considered it beneficial to perform the ACL augmentation procedure without sacrificing the remaining remnant in terms of proprioception, biomechanical functions, and vascularization of the graft. This study will present the ACL augmentation procedure for patients with partial ACL rupture. We believe that the described technique can be a treatment option for patients whose ACL remnants are left in certain conditions.

Arthroscopic Identification of Isolated Tear of the Posterolateral Bundle of the Anterior Cruciate Ligament

The goal of this study was to arthroscopically identify and assess the progressive changes in isolated ruptures of the posterolateral bundle of the anterior cruciate ligament (ACL) over time. This prospective study investigated 174 patients for isolated posterolateral bundle tears during arthroscopic ACL reconstruction. The preoperative side-to-side anterior laxity was measured in all patients. The torn ACLs were inspected and analyzed arthroscopically to determine the tear pattern. Complete ACL tears were identified in 78.7% of patients and partial ACL tears in 21.3%. Isolated anteromedial bundle tears were identified in 22 patients and posterolateral bundle tears in 15 patients. Statistical analysis showed a significant difference in preoperative differential knee laxity between the group with complete ACL rupture and the group with partial ACL rupture. On arthroscopic evaluation, the posterolateral bundle had retracted distally toward the tibial surface over time. The amount of retraction was correlated to the time period from injury to reconstruction. In this study the exact diagnosis of an ACL partial tear was made at arthroscopy in all cases. Our observations confirm the evolution of the ruptured posterolateral bundle, which shows a retraction toward the tibia over time. Level II, development of diagnostic criteria based on consecutive patients with a universally applied gold standard.

3-T MR imaging of partial ACL tears: a cadaver study

Magnetic resonance imaging (MRI) is the most commonly used diagnostic imaging procedure for suspected injuries to the anterior cruciate ligament (ACL). However, MRI has less utility for the evaluation of partial ACL tears. The goal of this study was to evaluate the possibility of distinguishing partial ACL tears applying the double bundle concept by dividing the ACL anatomy in the anteromedial (AM) and posterolateral bundle (PL). Six human cadaver knees were used in this laboratory study. The protocol consisted of sagittal, oblique coronal, and oblique sagittal proton-density-weighted fast spin echo sequences. After MRI the AM and the PL bundle were severed to mimic different partial ACL rupture patterns. MRI scanning of each knee was repeated, to record the quantitative parameters tilt and ACL angles and discontinuity as a nonquantitative parameter. Three orthopaedic surgeons and two radiologists were enlisted as blinded observers to evaluate the images. The transection patterns could be differentiated by evaluating discontinuity both in the paracoronal and in the sagittal plane. Evaluating the transection patterns, the AM bundle reached a better result in both planes compared to the PL bundle and the paracoronal plane had a better result in assessing the transection patterns compared to the sagittal plane for the PL bundle. Partial ACL transections could predictably be recognized on oblique sagittal and oblique coronal planes utilizing 3-T MRI technology. This concept allows a more precise description of ACL rupture patterns and might lead to a more distinctive approach for reconstructive surgery. The presurgical planning could be improved by applying a treatment algorithm based on a description of each bundle as intact or ruptured, leading to a reconstruction of the torn and a preservation of the intact bundle.

Cyclops syndrome occurring after chronic partial rupture of the anterior cruciate ligament without surgical reconstruction

Cyclops syndrome is one of the specific causes of loss of extension of the knee following anterior cruciate ligament (ACL) reconstruction. This syndrome is manifest by progressive loss of knee extension associated with pain and audible clunk at terminal extension caused by a pedunculated nodule of fibrovascular proliferative tissue usually arising from a graft. Recent published reports, however, have described Cyclops syndrome also developing after a partial ACL rupture without surgical reconstruction. In most cases, Cyclops syndrome generally occurred within 2 months after reconstruction surgery or rupture. Here we report on the case of a patient with symptoms and arthroscopic and histological findings compatible with Cyclops syndrome that developed after a chronic partial ACL rupture that occurred 23 years ago. To our knowledge, this is the first case report of Cyclops syndrome occurring after chronic partial ACL rupture.

Cyclops syndrome occurring after partial rupture of the anterior cruciate ligament not treated by surgical reconstruction

Cyclops syndrome is one of the specific causes of loss of extension of the knee following anterior cruciate ligament (ACL) reconstruction. The syndrome is manifested by progressive loss of extension associated with pain and audible clunk at terminal extension caused by a pedunculated nodule of fibrovascular proliferative tissue usually arising from the graft. The entity has been described recently and has been reported exclusively as a complication of ACL reconstructions. We report the case of a patient with symptoms and arthroscopic and histological findings compatible with cyclops syndrome that developed after a partial ACL rupture that was not treated by surgical reconstruction. A different etiology and classical histological and immunohistological microscopic analysis of the nodule presented in this report may further clarify the pathogenesis of the cyclops syndrome.

Long-Term Prognosis for Acute Partial Anterior Cruciate Ligament Rupture

Long-Term Prognosis for Acute Partial Anterior Cruciate Ligament Rupture

Eighteen- to twenty-five-year follow-up after acute partial anterior cruciate ligament rupture.

Of 22 consecutive patients with minor knee instability after a partial rupture of the anterior cruciate ligament, all could be reexamined after a mean of 12 years and all but 1 could be reexamined after a mean of 20 years. Three patients needed surgery during the follow-up period, but nobody had an anterior cruciate ligament reconstruction. The Lysholm knee function score was excellent and did not change between 12 and 20 years. Patients had decreased their activities from contact sports before injury to physical fitness activities at the late follow-up. Four patients changed activities because of a knee problem. The quality of life score was somewhat higher than may be expected in an age-matched average population. At late follow-up, eight patients had a 1+ Lachman sign, two a 2+ Lachman sign, and one a positive pivot shift. Also at late follow-up, 7 knees showed no signs of radiographic osteoarthrosis, 10 had Fairbank's signs, and 3 had minor and 1 a major joint space reduction. Of the 12 patients with longitudinal radiographic observation, 3 knees had developed a higher degree of osteoarthrosis, and 9 had remained unchanged. The patients had a mean age of 48 years at the late follow-up. This suggests that the results may be regarded as final outcome after this specific knee injury.

Lumbar Meningioma in a Dog

Lameness may be the only detectable clinical sign in spinal meningiomas. An unusually young dog was diagnosed with lumbar meningioma whereas it had been referred for further evaluation of a previously treated partial anterior cruciate ligament rupture. Comparative aspects with the human counterpart are presented, showing prospects for improvement of treatment in the veterinary field.

Partial ACL rupture: an MR diagnosis?

We sought to clarify the ability of magnetic resonance imaging (MR) to show partial anterior cruciate ligament (ACL) ruptures and to allow distinction of partial from complete ACL ruptures. Eighty-eight patients were studied by arthroscopy and MR (36 with normal ACLs, 21 with partial ACL ruptures, and 31 with complete ACL ruptures). MR studies were interpreted by an experienced, blinded reader. MR examinations were also independently scored with respect to four primary and seven secondary signs, and these data were analyzed using discriminant analysis. The sensitivity of MR is lower for partial than for complete ACL ruptures. Most detected partial ACL ruptures resemble complete ruptures on MR. Secondary signs do not significantly improve detection of partial ACL ruptures, but they do help to distinguish partial from complete ACL ruptures. Displacement of the posterior horn of the lateral meniscus and popliteus muscle injury are indicative of complete ACL rupture. The majority of partial ACL ruptures are shown by MR, but MR is less sensitive for partial than for complete ACL rupture. The distinction of partial from complete ACL rupture on MR examination, while problematic, is slightly improved by assessment of secondary signs.

Function of the quadriceps and hamstrings muscles in knees with chronic partial deficiency of the anterior cruciate ligament. Isometric and isokinetic evaluation.

We assessed the isokinetic and isometric strength and power profile of the knees of 37 patients who had a previous grade II sprain (partial tear) of the anterior cruciate ligament. Of the 37 knees, 11 had an isolated partial anterior cruciate ligament rupture and 26 had a partial anterior cruciate ligament rupture combined with a partial medial collateral ligament rupture. The Cybex II isokinetic dynamometer was used in the measurements. Eight years after the injury, the mean strength deficit of the injured knees was minimal when compared with the uninjured side. In the hamstrings of both groups, the relative strength deficit increased significantly with a higher speed of isokinetic movement (P less than 0.05). Compared with the strength parameters (peak torques), the other functional parameters (total work, average power, and peak angular impulse) of the injured knees showed some, but not significantly greater, deficits (hamstrings, 7% to 10%; quadriceps, 4% to 10%). We found that the general thigh muscle function in knees with old grade II sprains of the anterior cruciate ligament appears adequate except in flexion where the strength deficits are significantly greater in higher speeds of isokinetic movement. Therefore, rehabilitation using high-speed flexion (and extension) exercises is recommended.