Posterolateral Structure Research Articles

Effect of modified Laprade technique on posterolateral ligament injury of knee

PurposeTo investigate the effect of modified Laprade technique on the reconstruction of posterolateral structure of knee and anterolateral ligament of knee in the treatment of posterolateral injury of knee.MethodsFrom December 2013 to June 2020, multiple ligament injury patients who received surgery in our hospital were collected in this research. These patients underwent a modified Laprade technique for posterolateral structural reconstruction of the knee. Lysholm scores of patients pre- and post-operation were recorded.ResultThe operations of the observation group or the control group patients were completed. There were no significant differences in gender, age, preoperative knee range of motion and preoperative Lysholm score. At the time of follow-up 1 month after operation, there was no significant difference in knee range of motion, dial-up test angle and Lysholm score between the observation and the control group. When followed up 1 year after operation, the Lysholm score of the observation group was higher than that of the control group. The difference was statistically significant. The same situation occurred in the range of motion of the knee in both groups. However, there was still no significant difference between the two groups in the dial-up test 1 year after operation, whether the knee flexion was 30° or 90°.ConclusionFor patients with posterolateral structure injury of knee, the modified Laprade technique is a feasible surgical technique.

Iatrogenic injury of posterolateral structures during femoral tunneling in anterior cruciate ligament reconstruction: A cadaveric study

ObjectiveCreating Femoral tunnel in Anterior Cruciate Ligament (ACL) reconstruction can be done through some portal. Transportal technique commonly preferred by Orthopedic Surgeon. However, this technique may possess some iatrogenic injury to knee structure especially in the posterolateral during the drilling. This study aim is to describe the most susceptible injured posterolateral structure of the knee during femoral tunneling from trans portal technique Anterior Cruciate Ligament (ACL) reconstruction. MethodsTwenty knees from ten cadavers was examined. Anterior Cruciate Ligament (ACL) reconstruction was simulated using the trans portal technique. Femoral drilling was performed with knee in 120 flexion. The cadaver was dissected to identify the injured posterolateral structure during femoral tunneling. The data collected was anatomy structure and the wound size. ResultsAll Twenty knees were included in the study. 90% of injured structure was iliotibial band. The next most common was plantaris (50%) dan gastrocnemius (45%) muscle. The other was biceps femoris muscle (20%). The least common injury was vastus lateralis (5%). No injury was observed in Lateral Collateral Ligament (LCL), popliteus tendon, and peroneal nerve. ConclusionTransportal technique during femoral drilling in Anterior Cruciate Ligament (ACL) reconstruction does do damage to some of the posterolateral structure. The injury was considered minimal and may not result in function deterioration. There is also no risk to common peroneal nerve.

Iatrogenic Injury to the Posterolateral Knee During Anterior Cruciate Ligament Reconstruction with Anteromedial Portal Technique

BACKGROUND: Femoral tunnel reaming through anteromedial portal, also known as transportal technique, allows for anatomic femoral tunnel placement in restoring anterior cruciate ligament (ACL) kinematics. This procedure may cause iatrogenic injury to the posterolateral structures of the knee.
 PURPOSE: This study aims to assess the risk of posterolateral structure injury in ACL reconstruction using transportal technique.
 METHODS: ACL reconstruction using transportal technique was performed in 20 patients. Clinical and radiological examination was performed preoperatively and 1 month postoperatively. Clinical examination included any pain or paresthesia on posterolateral area of the knee, varus alignment of the knee, abnormal gait, and specific tests for posterolateral stability. Radiological evaluation was plain radiography and stress radiography for posterolateral stability, and magnetic resonance imaging (MRI) for assessing structural damage.
 RESULTS: Post-operative evaluation showed pain in posterolateral area in five patients, numbness on posterolateral knee in one patient, both pain and numbness in two patients and lateral gastrocnemius muscle injury on MRI in six patients. We did not find varus knee alignment and abnormal gait. Specific tests were negative in post-operative evaluation. Post-operative radiographic imaging did not show the sign of lateral widening.
 CONCLUSION: Femoral tunnel drilling using transportal technique in ACL reconstruction is safe even it might risk to damage lateral gastrocnemius muscle, according to clinical and MRI findings.

Posterolateral structure reconstruction for the chronic multiple ligament injuries of the knee

Combined anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) injuries results in severe functional knee disability. The posterolateral structure (PLS) injuries are commonly associated with PCL and/or ACL injuries by traffic accident or high energy trauma. The PCL is the primary restraint structure to posterior tibial translation of the knee. The PLS injury promote the functional disability of the PCL insufficiency. However, the treatment strategy for combined ligamentous injuries of the knee with the PLS insufficiency remains controversial. The authors have been performed PLS reconstruction using an autogenous biceps femoris tendon (BFT) for the chronic posterolateral (PL) instability of the knee. In this article, the surgical technique, and clinical outcomes of PLS reconstruction for the chronic PLS insufficiency with PCL and/or ACL ruptures.

Midterm outcomes following anatomic-based popliteus tendon reconstructions

The purpose of this study was to document subjective outcomes following anatomic-based reconstruction of the popliteus tendon when the popliteus tendon was the only injured posterolateral knee structure. It was hypothesized that popliteus tendon reconstruction would result in improved patient outcomes after surgery regardless of the concurrent ligamentous or intra articular pathology. A consecutive series of 5 patients with a median age of 23years (range, 22-36years) who underwent anatomic popliteus tendon reconstruction along with concomitant ligament reconstruction or meniscus repair (if needed) were included in this study. All patients completed pre-operative and post-operative subjective questionnaires, which included the Lysholm score to document function, the Tegner activity scale to document activity level, and a patient satisfaction with outcome question. All patients were available for a final follow-up at a median time of 2.8years (range, 2-3.9years) following the index surgery. Three patients had a combined popliteus tendon and posterior cruciate ligament reconstruction. Two of the three PCL reconstructions were revision procedures. The Lysholm score improved to from 53 (range, 34-90) to 91 (range, 44-100) at post-operative follow-up. The median pre-operative Tegner activity scale improved from 3 (range, 0-9) to a median score of 4.8 (range, 2-7) at post-operative follow-up. The median patient satisfaction with outcome was 9 (range, 7-10). The dial test at 30° and 90° improved in all patients following surgery. Anatomic-based popliteus tendon reconstructions resulted in improved outcomes and a high patient satisfaction in patients with a complete tear of the popliteus tendon and symptomatic knee instability. IV, case series.

The effects of posterior cruciate ligament deficiency on posterolateral corner structures under gait- and squat-loading conditions: A computational knee model.

ObjectivesThe aim of the current study was to analyse the effects of posterior cruciate ligament (PCL) deficiency on forces of the posterolateral corner structure and on tibiofemoral (TF) and patellofemoral (PF) contact force under dynamic-loading conditions.MethodsA subject-specific knee model was validated using a passive flexion experiment, electromyography data, muscle activation, and previous experimental studies. The simulation was performed on the musculoskeletal models with and without PCL deficiency using a novel force-dependent kinematics method under gait- and squat-loading conditions, followed by probabilistic analysis for material uncertain to be considered.ResultsComparison of predicted passive flexion, posterior drawer kinematics and muscle activation with experimental measurements showed good agreement. Forces of the posterolateral corner structure, and TF and PF contact forces increased with PCL deficiency under gait- and squat-loading conditions. The rate of increase in PF contact force was the greatest during the squat-loading condition. The TF contact forces increased on both medial and lateral compartments during gait-loading conditions. However, during the squat-loading condition, the medial TF contact force tended to increase, while the lateral TF contact forces decreased. The posterolateral corner structure, which showed the greatest increase in force with deficiency of PCL under both gait- and squat-loading conditions, was the popliteus tendon (PT).ConclusionPCL deficiency is a factor affecting the variability of force on the PT in dynamic-loading conditions, and it could lead to degeneration of the PF joint.Cite this article: K-T. Kang, Y-G. Koh, M. Jung, J-H. Nam, J. Son, Y.H. Lee, S-J. Kim, S-H. Kim. The effects of posterior cruciate ligament deficiency on posterolateral corner structures under gait- and squat-loading conditions: A computational knee model. Bone Joint Res 2017;6:31–42. DOI: 10.1302/2046-3758.61.BJR-2016-0184.R1.

The popliteal fibular ligament in acute knee trauma: patterns of injury on MR imaging.

To describe the patterns of injury associated with injury to the popliteofibular ligament injury. A retrospective review was performed of 180 MRI scans undertaken for acute knee trauma. Scans were excluded if the time of injury was over 4 weeks from the time of the scan, or if there was a history of septic arthritis, inflammatory arthropathy, previous knee surgery, or significant artefact. An agreed criterion for assessing the structures of the posterolateral ligamentous complex was defined and in each scan, the popliteofibular ligament (PFL) was scored as normal or injured. The menisci, ligaments, and tendons of each knee were also assessed. The mean age was 25.7 years (range, 9-65 years) and 72.2% (n = 130) patients were male. The PFL was injured in 36 cases (20%). There is a significant association between PFL injury and ACL rupture (p = 0.0001), ITB injury (p = 0.0001), PCL injury (p = 0.0373), in addition to associations with injury to other posterolateral corner structures including the lateral collateral ligament (p = 0.0001), biceps femoris tendon (p = 0.0014), and popliteus tendon (p = 0.0014). Of our series of PFL injuries, nine cases (25%) were associated with further injuries of posterolateral corner structures and in 27 cases (75%) the PFL was the only posterolateral corner structure torn. PFL injury is not uncommon in acute knee trauma and is associated with significant internal derangement of the knee, especially anterior cruciate ligament rupture, ITB sprain, and injury to other structures within the posterolateral corner.

The "lateral gutter drive-through" sign revisited: a cadaveric study exploring its real mechanism based on the individual posterolateral structure of knee joints.

Although the validity of the "lateral gutter drive-through" (LGDT) test has been proved to offer high sensitivity and specificity in diagnosing the posterolateral rotational instability of knee joints, the real mechanism on how the injury pattern of individual posterolateral knee structure triggers the positive LGDT sign still remains unknown. A certain amount of popliteus tendon (POP-T) laxity resulted from specific injury patterns of individual posterolateral knee structure or some degree of medial structural injury will lead to positive LGDT sign. Controlled laboratory study. Seven non-paired intact cadaveric knees were divided into four groups and tested under unique sequential sectioning sequences including: (1) distal POP-T and popliteofibular ligament (PFL) (n = 2); (2) PFL and distal POP-T (n = 3); (3) lateral collateral ligament (LCL), distal POP-T and PFL (n = 1); (4) superficial medial collateral ligament (sMCL), deep MCL, posterior oblique ligament (POL), anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) (n = 1). The LGDT tests and the measurements of external tibial rotational angle (ETRA) were first performed on all the intact knees and then at each time point when an additional structure was sectioned. Results of each LGDT test and the absolute value of increased ETRA compared with the intact knee were recorded. Each knee was tested at 30° of flexion. A navigation system was used to measure motion changes of the tibia with respect to the femur. Initially, the LGDT tests all showed negative on each of the intact knee. Isolated sectioning of the distal POP-T, PFL or the LCL produced increased but insignificant ETRA with the LGDT tests still negative. However, simultaneous sectioning of the distal POP-T and PFL produced significantly increased ETRA with the LGDT tests changed to positive. In addition, for the knee with medial structural injuries, the LGDT test could also be positive only when the posteromedial structures (sMCL, deep MCL, POL) and the cruciate ligaments (ACL and PCL) were all sectioned. In this cadaveric sequential sectioning study, the LGDT test showed positive merely at the following two situations: (1) the distal POP-T and PFL were both sectioned; (2) the posteromedial structures (sMCL, deep MCL and POL) and the cruciate ligaments (ACL and PCL) were all sectioned. Accuracy of the LGDT test in diagnosing acute or chronic posterolateral corner (PLC) injuries will improve with the information in this study. It was the combined POP-T and PFL injuries that finally led to a positive LGDT sign. However, one should be cautious to use the LGDT test in diagnosing the PLC injuries when posteromedial structures and cruciate ligaments were all involved.

Anteromedial marginal fracture of medial tibial plateau without significant knee ligamentous injury in hypermobility patient: a case report and review of literature

Anteromedial rim fracture of medial tibial plateau is a rare fracture pattern with only a small number of case reports in the literature. However, it is highly likely that is associated with specific significant soft tissue injuries, especially posterior and posterolateral corner structure, and medial meniscus injury. It is thought this fracture is caused by hyperextension and varus rotation mechanism. The previous reports highlight the typical pattern of severe concomitant knee ligament injury associated with this fracture that always require surgical repair to restore knee stability and function. In this report, we present an unusual case with a history of generalized joint laxity and acute anteromedial marginal fracture of medial tibial plateau without associated significant ligament damage, together with a literature review of this condition. We believe this case report introduces new insights into this unique fracture pattern.

Technical note: ‘Glove assistant’ for ankle surgery

The approach to the fibula and softtissues around the posterolateral aspect of the ankle is commonly used in ankle surgery both in the elective and trauma settings. A simple technique is described that will assist the surgeon in positioning the ankle during surgery without the need for a surgical assistant. The technique also allows easy switching of ankle positions and places the ankle independently during fluoroscopic imaging of the ankle mortice. BACKGROUND The fibula is a posterolateral structure and therefore the surgical approach to the lateral malleolus is made simpler by internally rotating the leg. Routinely, a surgical assistant or a sandbag positioner under the ipsilateral buttock is used to maintain the leg in this position. When sandbags are used, the approach to medial aspect of the ankle may be impeded and invariably the sandbag is removed to allow external rotation of the leg. A simple and effective technique is described to assist the positioning of the ankle which allows easy switching of ankle positions without the need for a surgical assistant. TECHNIQUE The patient is positioned supine on the operating table and draped as per standard technique. A large sterile glove is used to envelope the contralateral foot with its’ overlying drape. Another sterile glove is used to cover the foot on the operative side and a kidney dish is positioned under the ankle. To internally rotate the leg, one finger extension from the glove on the operative side is tied to a finger extension on the contralateral glove (Figure 1). Figure 1 Figure 1: Operated ankle held in internal rotation using ‘glove assistant’ The degree of internal rotation can be varied by moving the ankle and kidney dish closer (less internal rotation) or further away (more internal rotation) from the other foot. When approach to the medial side of the ankle is required, the tied finger extension is simply cut. DISCUSSION The technique negates the need for a surgical assistant and also provides excellent positioning of the ankle for intraoperative fluoroscopic imaging of the ankle mortice.

The Reproducibility and Repeatability of Varus Stress Radiographs in the Assessment of Isolated Fibular Collateral Ligament and Grade-III Posterolateral Knee Injuries

Objective measures to quantitate the amount of lateral compartment opening for patients with lateral and posterolateral knee injuries have not been well documented. The purpose of the present study was to measure lateral compartment opening secondary to applied varus stresses following posterolateral corner structure sectioning and to develop radiographic guidelines to quantify the amount of lateral compartment gapping seen with these injuries.Ten nonpaired fresh-frozen cadaver lower extremities were used. Two varus loads, a 12-Nm moment and a clinician-applied varus stress, were applied to the intact knees and after sequential sectioning of the fibular collateral ligament, popliteus tendon, popliteofibular ligament, and anterior and posterior cruciate ligaments to simulate degrees of posterolateral knee and associated combined cruciate ligament injuries. The shortest distance between the most distal subchondral bone surface of the lateral femoral condyle and the corresponding lateral tibial plateau was measured to quantify lateral compartment opening and was analyzed on digital radiographs. Three observers were used to determine interobserver reproducibility and intraobserver repeatability.In the intact knee, the mean lateral compartment gapping due to a 12-Nm moment and a clinician-applied varus stress was 8.9 and 9.7 mm, respectively. Lateral gapping significantly increased by 2.1 and 2.7 mm in association with sectioning of the fibular collateral ligament and by 3.4 and 4.0 mm in knees with a simulated posterolateral corner injury for each respective load-application technique (p < 0.0001 for all comparisons). Intraobserver repeatability was high, with all observers independently obtaining an intraclass correlation coefficient of 0.99, whereas the analysis of interobserver reproducibility demonstrated an intraclass correlation coefficient of 0.97.Measurements with use of current clinical digital imaging systems can be used to quantify the amount of lateral compartment knee opening. Clinicians should suspect an isolated fibular collateral ligament injury if opening on clinician-applied varus stress radiographs increases by approximately 2.7 mm and a grade-III posterolateral corner injury if values increase by approximately 4.0 mm.Varus stress radiographs appear to provide an objective and reproducible measure of lateral compartment gapping that should prove useful for the diagnosis, management, and postoperative follow-up of patients with fibular collateral ligament and posterolateral knee injuries.

Simultaneous anterior and posterior cruciate ligament reconstruction in chronic knee instabilities: surgical concepts and clinical outcome

The purpose of this study was to evaluate the clinical results of simultaneous arthroscopically assisted reconstruction of anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) using autogenous tendon grafts in chronic knee injuries. Nineteen patients (17 men and 2 women) with chronic multi-ligamentous injuries underwent one-stage ACL and PCL reconstruction. ACL, PCL and medial collateral ligament were reconstructed in seven knees, and ACL, PCL and posterolateral structure were reconstructed in two knees. Function of the operated knee was evaluated according to the International Knee Documentation Committee (IKDC) and Lysholm scale. Anterior and posterior knee laxity was examined with a KT-2000 arthrometer. Eighteen of 19 patients were able to return for follow-up and were evaluated objectively and subjectively. The average patient age at surgery was 30.5 years, and the average postoperative follow-up was 3.5 years. No patients showed loss of knee extension more than 5 degrees , while three patients revealed loss of knee flexion more than 16 degrees . The mean postoperative total anterior-posterior side-to-side difference was 1.9 +/- 1.5 mm at 20 degrees and 2.1 +/- 1.9 mm at 70 degrees . The average of the Lysholm score was 95.1 points at the final follow-up. At the IKDC evaluation, three patients were grade A, 11 were grade B, 3 were grade C, and 1 patient was grade D. The results showed the effectiveness and safety of one-stage reconstruction of combined ligamentous injuries of the knee that can adequately restore satisfactory stability.

The Effect of a Proximal Tibial Medial Opening Wedge Osteotomy on Posterolateral Knee Instability

Background Increased stability of posterolateral corner knee injuries has been observed clinically after proximal tibial medial opening wedge osteotomies. Hypothesis Static varus and external rotatory stability will be significantly improved in a knee with a grade 3 posterolateral knee injury after a proximal tibial medial opening wedge osteotomy. Study Design Controlled laboratory study. Methods Biomechanical testing of 10 nonpaired, cadaveric knees was performed in the intact state, after transection of the posterolateral corner (fibular collateral ligament, popliteus tendon, and popliteofibular ligament), and after a 10-mm proximal tibial medial opening wedge osteotomy. Loading conditions consisted of 12 N.m varus moments and 6 N.m external rotation torques. Six degrees of freedom motion analysis was used to assess motion changes, and a buckle transducer was used to measure the force on the superficial medial collateral ligament during applied loads. Results After transection of the posterolateral corner structures, a significant increase in varus rotation was found to applied varus moments with a mean increased opening of 5.9° to varus stress at 30° and 5.8° at 90° of knee flexion. After proximal tibial medial opening wedge osteotomy, varus rotation was increased by a mean of 1.6° at 30° and 1.7° at 90° of knee flexion compared with the intact state. There was a significant decrease in varus rotation to a varus moment after osteotomy compared with the posterolateral sectioned state at both 30° and 90°. External rotation of the knee increased by 4.7° at 30° and 4.8° at 90° after posterolateral structure sectioning compared with the intact state. After the osteotomy, there was a significant decrease in external rotation compared with the posterolateral sectioned state, and there was no significant difference in external rotation compared with the intact state. There was a significant increase in force on the superficial medial collateral ligament after the osteotomy compared with both the intact and posterolateral corner cut state for both an applied varus moment and external rotation torque at both 30° and 90°. Conclusion Our results demonstrate that a proximal tibial medial opening wedge osteotomy decreased varus and external rotation laxity for posterolateral corner–deficient knees. Concurrently, an increase in force was observed on the superficial medial collateral ligament compared with the native state. Clinical Significance The improved stability observed in some patients with grade 3 posterolateral knee injuries after a proximal tibial medial opening wedge osteotomy appears to at least in part be due to tightening of the superficial medial collateral ligament. The long-term consequences of the increased force on the superficial medial collateral ligament on the medial compartment, and whether it elongates with time, merit further investigation.

A Prospective Magnetic Resonance Imaging Study of the Incidence of Posterolateral and Multiple Ligament Injuries in Acute Knee Injuries Presenting With a Hemarthrosis

The purpose of this study was to determine whether the incidence of posterolateral knee injuries, as well as other concurrent knee ligament injuries, could be obtained from a prospective evaluation of magnetic resonance imaging scans in patients with an acute knee injury with a hemarthrosis. We prospectively documented all patients with acute (within 30 days) knee injuries with a hemarthrosis over a 90-day period who underwent 1.5-T magnetic resonance imaging at a large referral imaging facility with 6 sites, effectively covering a large metropolitan area. The anterior cruciate ligament, superficial medial collateral ligament, and posterior cruciate ligament (PCL) and the following individual structures of the posterolateral corner were evaluated for high-grade injury: fibular collateral ligament, popliteus tendon, and popliteofibular ligament. Out of 331 consecutive acute knee injuries with a hemarthrosis, 265 ligament injuries occurred in 187 patients (56%). Of these 187 patients with ligament injuries, 126 had isolated ligament injuries and 61 (33%) had combined multiple ligament injuries. Of the 187 patients with knee ligament injuries, 83 (44%) had isolated anterior cruciate ligament tears, 28 (15%) had isolated superficial medial collateral ligament tears, 11 (5%) had isolated PCL tears, and 4 (2.1%) had isolated posterolateral knee tears. Of the patients with posterolateral knee structure injuries, 87% (26/30) had multiple ligament injuries, with the overall incidence of posterolateral knee injuries among all knee ligament injuries being 16% and among all acute knee injuries with a hemarthrosis being 9.1%. Of the 27 patients with PCL tears, 16 (52%) had combined multiple ligament injuries. This study shows that in this population, the incidence of posterolateral knee injuries in patients with acute knee ligament injuries with a hemarthrosis was 9.1%. It also verified that most PCL and posterolateral corner injuries occur in combination with other ligament injuries. Level II, development of diagnostic criteria on the basis of consecutive patients with a universally applied gold standard.

The role of posterolateral structure and posterior cruciate ligament in external rotatory stability of the knee

To investigate the changes of external rotation stability of the knee after the breaking and reconstruction of the posterolateral structure (PLS) of knee joint. The femurs of 16 fresh cadaveric lower limbs were fixed to the base of rotating holders with the knee joints in full extension, or at an angle of 30 degrees , 60 degrees , or 90 degrees ; while the tibia was attached to a free rotary holder. The external rotation of the tibia was measured with a 5 kg x m x s(-2) tibial torque. The external rotation angle of the tibia was measured after the transectioning of the popliteus tendon (PT), popliteus muscle (PM), popliteofibular ligament (PFL), fibular collateral ligament (LCL), or popliteus tendon (PT). Autogenous hamstring tendon was used to reconstruct the PCL, and the Achilles tendon was used to reconstruct the PFL and PT, then the external rotation angle of the tibia was measured again. The isolated sectioning of PCL did not increase the tibial external rotation angle. When the knee was flexed the external rotation angle was 14.1 degrees in the intact knee and was 14.57 degrees in the PCL transectioning group (q = 0.47, P > 0.05). After the PFL was sectioned, when the knee joint was flexed at 60 degrees the external rotation angle was 16.94 degrees (q = 2.84, P < 0.05). After the PT was sectioned (PCL + PFL + PT), when the knee joint was flexed at 60 degrees the external rotation angle was 28.1 degrees (q = 14.01, P < 0.05). After isolated PCL reconstruction the external rotation angle was still bigger than that of the normal knee: for example, when the knee joint was at the angle of 60 degrees the external rotation angle was 27.67 degrees (q = 0.425, P < 0.05). There was a significant decrease in external rotation compared with PT section (P < 0.05). After the combined PCL + PLS reconstruction when the knee joint was at the angle of 60 degrees the external rotation angle of the knee was 14.51 degrees (q = 0.412, P < 0.05), however, the range of change was less than 1 degree. Isolated PCL section produces no change in external rotation. Complex injury of PCL and PSL can produce instability in external rotation. PT has the greatest important role to resist external rotation, then the greatest increase in external rotation can be found after PT is sectioned. Isolated PCL reconstruction can not completely restore the posterolateral stability of the knee. PCL reconstruction can partly restore the stability of the external tibial rotation. Only the combined PC + PLS reconstruction can reset the knee to physiological stability of external rotation.

Anatomical study of the popliteofibular ligament and surrounding structures

Although the popliteofibular ligament (PFL) is an important posterolateral structure of the knee joint, the anatomical characteristics of this ligament remain unclear. We morphologically classified and measured the PFLs from 78 cadaver knees. The PFL was observed in all knees, and it was classified into type I (with one layer) or type II (with two layers). The mean lengths of the anterior and posterior margins were 12.7 and 6.8 mm, respectively; and the mean width and thickness were 10.4mm and 2.1mm, respectively. The PFL inclined forward at a mean sagittal angle of 20.7°, which is similar to the 21.2° of the posterior cruciate ligament, indicating that the PFL contributed to posterolateral rotatory stability.

Reconstruction of the Posterolateral Structure of the Knee.

Reconstruction of the Posterolateral Structure of the Knee.

The effects of grade III posterolateral knee complex injuries on anterior cruciate ligament graft force. A biomechanical analysis.

To determine if untreated grade III injuries of the posterolateral structures contribute to increased force on an anterior cruciate ligament graft, we measured the force in the graft in cadaveric knees during joint loading after reconstruction with otherwise intact structures and in the same reconstructed knees after selected cutting of specific posterolateral knee structures. Tests were first performed on the knee with the posterolateral structures intact and then after sequential sectioning of the fibular collateral ligament, popliteofibular ligament, and popliteus tendon. The graft force was significantly higher after fibular collateral ligament transection during varus loading at both 0 degree and 30 degrees of knee flexion than it was for the same loading of the joint with intact posterolateral structures. In addition, coupled loading of varus and internal rotation moments at 0 degree and 30 degrees of flexion further increased graft force beyond that with varus force alone. The increase in graft force remained significant with additional sequential cutting of the popliteofibular ligament and popliteus tendon. We believe this study supports the clinical observation that untreated grade III posterolateral structure injuries contribute to anterior cruciate ligament graft failure by allowing higher forces to stress the graft.