Varus Laxity Research Articles

The Fibular Collateral Ligament Is a More Important Restraint to Varus Laxity Compared to the Anterolateral Complex in the Anterior Cruciate Ligament–Deficient Knee in a Cadaveric Biomechanical Study

PurposeThe purpose of this study was to compare the influence of the fibular collateral ligament (FCL) and the anterolateral complex (ALC) on varus knee laxity in paired anterior cruciate ligament (ACL)-deficient cadaveric knees using varus stress radiographs. MethodsVarus laxity in nine paired (N=18, mean age 73.8 years) human cadaveric knees was assessed using varus stress radiographs with a 12 Nm varus stress applied at 20° of knee flexion. All knees underwent testing in the intact state and following ACL sectioning. One knee of each pair was randomly assigned to undergo FCL sectioning and the contralateral knee was assigned to undergo ALC sectioning (anterolateral ligament [ALL] followed by the Kaplan fibers). ResultsBoth FCL sectioning and ALC (ALL and the Kaplan fibers) sectioning resulted in increased lateral compartment gapping compared to the intact state, 2.44 mm and 1.13 mm, respectively. ALL sectioning with intact Kaplan fibers did not result in increased lateral compartment gapping. Paired knee comparison revealed a significantly greater influence of the FCL than the ALC in restraining lateral compartment gapping under an applied varus stress (p=0.0003). ConclusionsSectioning the FCL resulted in significantly greater lateral compartment gapping under a varus stress than combined sectioning of the ALL and Kaplan fibers in an ACL deficient knee, although both scenarios resulted in significantly increased gapping compared to the intact state. Sectioning of the ALL with intact Kaplan fibers did not result in increased lateral compartment gapping. Clinical RelevanceThe FCL is the most important structure in restraining varus laxity in the ACL deficient knee and the ALC is of secondary importance in restraining varus laxity. In ACL deficient patients with a high-grade pivot shift, mild varus laxity on clinical examination, and an intact FCL on MRI, injury to the anterolateral complex should be considered and may be evaluated with varus stress radiographs. This study validates prior biomechanical studies of FCL deficiency and demonstrates that approximately 1 mm increase in lateral compartment gapping on varus stress radiographs may occur secondary to ALC injury and clinicians should be aware of this when considering treatment for ACL deficient patients with high-grade anterolateral laxity.

Poster 262: Biomechanical Evaluation of New Fixation Techniques for Posterolateral Corner Reconstruction

Objectives: Posterolateral corner (PLC) injuries intricately damage vital knee stabilizers. Both fibular and tibial-based reconstruction techniques are used and are classically described with use of interference screw fixation of the graft at the femur. However, adjustable loop buttons may conserve more bone stock, reduce the risk of tunnel convergence in the setting of multiligament reconstruction, and provide more versatile and reproducible tensioning ability compared to interference screws. Further, tape-reinforced graft suturing has been shown to have favorable biomechanical properties over traditional graft suturing techniques. There is no study comparing interference screw fixation to adjustable loop buttons in the context of tape-reinforced grafts in PLC reconstruction. Therefore, the purpose of this study is to biomechanically compare adjustable loop button fixation with interference screws for fibular collateral ligament and popliteal tendon fixation to the femur for PLC reconstruction. We hypothesize there will be no difference in varus or external rotation laxity between the two methods of fixation. Methods: The biomechanical study was conducted on 10 cadaveric knee specimens in a non-destructive repeated measures sequence using a 6-degree of freedom robotic arm (Fig. 1), under four conditions: (1) Native (2) PLC reconstruction with adjustable-loop suspensory button fixation, (3) PLC reconstruction interference screw fixation, and (4) PLC injured state. Reconstruction was performed using a fibular based technique as described by Arciero et al. FCL and popliteal tendon limbs were tensioned independently with 100N of force. The FCL was tensioned with the knee at 30° of flexion and 3 N∙m of valgus torque in neutral rotation. The popliteal tendon limb was tensioned at 60° of knee flexion with neutral rotation. Biomechanical evaluation consisted of a 5-N∙m external rotation test and a 10-N∙m varus test, performed at 0°, 30°, 60° and 90° of flexion. Results: All differences are presented in the order of 0°, 30°, 60° and 90° of flexion. Cutting the PLC significantly increased external rotation laxity (Fig. 2) (+3.8°, +9.7°, +9.9°, +7.6, all P<0.001) and varus laxity (Fig. 3) (+1.7°, +4.5°, +3.7°, all p<0.001, no significant difference at 90° of flexion) with respect to native. PLC reconstruction with suspensory fixation significantly over constrained external rotation (Fig. 2) (-3.5° P=0.002, -4.3° P<0.001, -4.1° P=0.002, -3.1° P=0.039) and varus (Fig. 3) (-1.5°, -2.1°, -2.4°, -2.1°, all P<0.001). PLC Reconstruction with interference screws similarly over constrained external rotation (Fig. 2) (-4.3°, -5.5°, -5.4°, -4.5°, all P<0.001) and varus (Fig. 3) (-1.8°, -2.5°, -2.9°, -2.8°, all P<0.001). There was no significant difference found between the suspensory fixation and the interference screw fixation in any test. Conclusions: Both reconstruction techniques restored the stability in external rotation and varus stress. No significant differences were found between the two fixation methods, validating both adjustable-loop suspensory buttons and interference screws as viable options for femoral fixation in the setting of PLC reconstruction. However, both methods over-constrained the knee in ER and Varus. This may be due to the increased stiffness of the tape-reinforced graft suturing, or over-tensioning of the grafts during fixation. The study tests a physiologic load but is limited since the specimen is not cyclically loaded or loaded to failure. This study evaluates and compares two PLC reconstruction techniques and their impact on knee stability. These findings provide quantifiable data to aid surgeons in making evidence-based, patient-specific decisions regarding appropriate PLCR technique. Biomechanically, the adjustable-loop suspensory fixation and the interference screw behave very similarly at time zero. Given this, surgeons may select an implant based on their comfort, training and/or patient specific needs. Further research is necessary to determine which implant performs the best in a clinical setting.

Autograft Versus Allograft in Posterolateral Corner Reconstruction: A Systematic Review and Meta-analysis.

Several approaches to surgical techniques and graft types exist in posterolateral corner (PLC) reconstruction. The literature lacks knowledge regarding outcomes after autograft versus allograft reconstruction for PLC injuries. To comprehensively review the current literature on PLC reconstruction and compare outcomes between autograft and allograft tissues. Systematic review; Level of evidence, 4. The PubMed and Scopus online databases were searched with the terms "PLC,""posterolateral knee,""posterolateral corner," and "reconstruction" in varying combinations. Patient characteristics, graft type, graft failure, surgical techniques, functional outcome scores, and varus laxity on stress radiographs were reviewed and compared between PLC reconstruction with autografts versus allografts. Included were 22 studies comprising 33 cohorts: 16 autografts (n = 280 knees) and 17 allografts (336 knees). There were 69 isolated PLC reconstructions (58 allografts and 11 autografts) and 493 multiligament reconstructions (269 autografts and 224 allografts). There was no difference in the mean patient age (30.5 vs 33.5 years, respectively; P = .11) or mean follow-up (39.5 vs 37.7 months, respectively; P = .68) between the autograft and allograft groups. There was no evidence to suggest a difference in graft failures between graft types (pooled mean autograft vs allograft: 0.44 vs 0.41 failures; P = .95). There was a significant difference in the mean postoperative Lysholm scores for autografts versus allografts (89.6 vs 85.5, respectively; P = .04). There was no difference between the cohorts in preoperative or postoperative International Knee Documentation Committee (IKDC) scores or postoperative varus laxity. Our review and meta-analysis indicated no significant differences in graft failure rates or objective outcomes after PLC reconstruction based on graft type alone. There was a significant difference in postoperative Lysholm scores in favor of the autograft group and no significant difference in IKDC subjective scores.

Anatomic Popliteus Tendon and Tibiofibular Joint Reconstructions

Background: The popliteus tendon is a primary stabilizer of external knee rotation and has been described as the “fifth ligament of the knee.” Injuries involving the posterolateral corner of the knee commonly involve the popliteus tendon; isolated injury to the popliteus tendon is relatively rare and usually involves a rotatory injury mechanism and symptoms of instability and pain. In this patient, there was a concomitant injury to the proximal tibiofibular joint. Indications: Popliteus tendon reconstruction is indicated for patients with abnormal external rotation on examination and symptoms of pain and instability. Proximal tibiofibular joint reconstruction is indicated for patients with instability of the tibiofibular joint. Technique Description: Preoperative examination under anesthesia is essential to determine the extent of external rotation and assess for additional posterolateral pathology. The popliteus tendon procedure begins with a meticulous common peroneal nerve neurolysis to minimize nerve irritation and decrease the risk of a postoperative foot drop. Semitendinosus and gracilis graft harvest is performed with at least 16 cm of graft length followed by tunnel reaming of the popliteus tendon femoral attachment and tibia tunnel identification and reaming. The femoral attachment of the popliteus tendon is secured, and the semitendinosus graft is anatomically oriented along the native path and passed from posterior to anterior through the femoral tunnel. The gracilis graft for anatomic proximal tibiofibular joint reconstruction requires an anterior to posterior tunnel through the fibular head. Finally, both grafts are secured in the tibial tunnel with the application of an anterior traction force. Results: A cadaveric study by LaPrade et al reported that an anatomic popliteus tendon reconstruction with a semitendinosus autograft significantly reduced external rotation laxity compared with the sectioned state. In addition, popliteus tendon reconstruction resulted in significantly decreased varus laxity, anterior tibial translation, and internal rotation. Discussion: This is a technique that effectively restores external rotation knee stability utilizing an anatomically oriented reconstruction of the popliteus tendon and tibiofibular joint. The popliteus tendon serves as a primary stabilizer to external rotation and facilitates static function of the knee. The proximal tibiofibular joint reconstruction restores the function of the posterior proximal tibiofibular joint ligaments. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Coronal Laxity at Flexion is Larger After Posterior-Stabilized Total Knee Arthroplasty Than With Cruciate-Retaining Procedures

BackgroundIt is unclear whether coronal stability differs between cruciate-retaining (CR) and posterior-stabilized (PS) total knee arthroplasty (TKA). The purpose of this study was to compare coronal laxity, radiological, and clinical outcomes between CR-TKA and PS-TKA. MethodsSeventy five CR-TKAs and 72 PS-TKAs with a minimum 2-year follow-up were retrospectively evaluated. Coronal laxity was assessed at knee extension and 80° of flexion on varus and valgus stress radiographs. Radiological evaluation included femoral-tibial angle, hip-knee-ankle angle, and positions of femoral and tibial components. Clinical evaluation included the modified Hospital for Special Surgery score, the Western Ontario and McMaster Universities Osteoarthritis index, and range of motion. ResultsPS-TKA resulted in significantly larger varus, valgus, and total laxities at 80° flexion (P = .034, .031, and 0.001, respectively) compared with CR-TKA, while no significant difference was found at extension (P = .513, .964, and .658, respectively). No statistical difference was found in radiological and clinical outcomes between CR-TKA and PS-TKA, but the functional scores were slightly better in CR-TKA. There were adverse correlations between varus laxity at flexion and the Western Ontario and McMaster Universities Osteoarthritis index, the modified Hospital for Special Surgery score, and range of motion (r = 0.933, −0.229, −0.472, respectively). ConclusionCoronal laxity at 80° of flexion was larger after PS-TKA than CR-TKA. In addition, clinical outcomes were adversely affected by the larger varus laxity at flexion. Care should be taken to maintain the coronal stability, especially at flexion, during surgery to obtain better patient-reported outcomes. Level of evidenceLevel III.

A Comprehensive Meta-analysis of Clinical and Biomechanical Outcomes Comparing Double-Bundle and Single-Bundle Posterior Cruciate Ligament Reconstruction Techniques

Background: Posterior cruciate ligament (PCL) reconstruction techniques have historically focused on single-bundle (SB) reconstruction of the larger anterolateral bundle without addressing the codominant posteromedial bundle. The SB technique has been associated with residual laxity and instability, leading to the development of double-bundle (DB) reconstruction techniques. Purpose: To perform a meta-analysis of comparative clinical and biomechanical studies to differentiate the pooled outcomes of SB and DB PCL reconstruction cohorts. Study Design: Meta-analysis and systematic review: Level of evidence, 3. Methods: Six databases were queried in February 2022 for literature directly comparing clinical and biomechanical outcomes for patients or cadaveric specimens undergoing DB PCL reconstruction against SB PCL reconstruction. Biomechanical outcomes included posterior tibial translational laxity, external rotational laxity, and varus laxity at 30° and 90° of knee flexion. Clinical outcomes included the side-to-side difference in posterior tibial translation during postoperative stress radiographs, risk of a major complication, and the following postoperative patient-reported outcome measures: Lysholm, Tegner, and International Knee Documentation Committee (IKDC) subjective and objective scores. A random-effects model was used to compare pooled clinical and biomechanical outcomes between the cohorts. Results: Fifteen biomechanical studies and 13 clinical studies were included in this meta-analysis. The DB group demonstrated significantly less posterior tibial translation at 30° and 90° of knee flexion (P < .00001). Additionally, the DB group demonstrated significantly less external rotation laxity at 90° of knee flexion (P = .0002) but not at 30° of knee flexion (P = .33). There was no difference in varus laxity between the groups at 30° (P = .56) or 90° (P = .24) of knee flexion. There was significantly less translation on stress radiographs in the DB group (P = .02). Clinically, there was no significant difference between the groups for the Lysholm score (P = .95), Tegner score (P = .14), or risk of a major complication (P = .93). DB PCL reconstruction led to significantly higher odds of achieving “normal” or “near normal” objective IKDC outcomes for the included prospective studies (P = .04) and higher subjective IKDC scores (P = .01). Conclusion: DB PCL reconstruction leads to superior biomechanical outcomes and clinical outcomes relative to SB PCL reconstruction. Re-creating native anatomy during PCL reconstruction maximizes biomechanical stability and clinical outcomes.

Comparison of three surgical techniques of posterolateral knee reconstruction: A cadaver study

BackgroundInjuries to the posterolateral corner (PLC) of the knee are often overlooked but, require reconstruction in order to restore stability in varus and external rotation. Among the many anatomic and non-anatomic PLC reconstruction techniques available, the modified Larson (mLR), LaPrade (LPR) and Versailles reconstruction (VR) procedures are widely used. HypothesisThe hypothesis was that anatomic PLC reconstruction (VR and LPR procedures) provides better restoration and control of external rotation. Patients and methodsFifteen fresh-frozen cadaveric knees were tested to compare the 3 procedures. Varus laxity on stress radiographs in full knee extension and external rotatory laxity on dial test at 30° flexion were quantified at 3 phases: intact knee, PLC sectioned and PLC reconstructed. ResultsMean varus laxity did not differ significantly between techniques in intact knees (p=.14), after PLC sectioning (p=.14) or after PLC reconstruction (p=.17). After PLC reconstruction, varus laxity was restored, with no statistical difference between mLR, VR and LPR compared to intact test values (respectively, -1.0, -1.3 and -1.5; p=.98). In all 3 groups, mean external rotation laxity on dial test at 30° flexion did not significantly differ between intact knees (p=.32) and after PLC sectioning (p=.15). After PLC reconstruction, the mLR technique was significantly less effective in restoring rotational stability than the VR and LPR techniques (p=.025). DiscussionThe VR technique provided similar outcomes to LPR for restoring stability in varus and external rotation. The 2 “anatomic” reconstruction procedures (VR and LPR) were significantly more effective than the modified Larson technique for external rotation control, confirming the study hypothesis. Consequently, it remains preferable to use anatomic techniques in multiligament injuries involving the PLC. Level of evidenceIV, cadaver study.

Postoperative Valgus Laxity and Medial Pivot Kinematics Are Significantly Associated With Better Clinical Outcomes.

The relative impact of soft tissue balance and knee laxity on clinical outcomes after total knee arthroplasty (TKA) is not fully understood. We analyzed associations among knee laxity, kinematics, and patient-reported outcomes. Knee Society Scores were recorded in 67 patients before and after primary TKA for osteoarthritis with varus deformity (N= 78). Varus and valgus laxity was measured in 78 knees using stress radiographs. Knee kinematics were measured fluoroscopically during stair ascent in 16 knees. On average, varus laxity decreased significantly, and valgus laxity increased significantly after TKA, although the net combined varus-valgus laxity did not change significantly. Postoperatively, the magnitude of valgus laxity correlated significantly with greater patient symptoms and satisfaction scores. Patients with medial pivot kinematics scored higher on patient satisfaction and standard activities. We found that postoperative valgus laxity and medial pivot kinematics were significantly associated with better clinical outcomes. These results emphasize the importance of careful preoperative planning and attention to intraoperative alignment and ligament balancing.

Effet synergique du ligament antérolatéral et de la capsule sur le contrôle de la laxité du genou dans les lésions traumatiques du ligament croisé antérieur : une étude cadavérique

IntroductionThere is much controversy about the practical role of the anterolateral ligament (ALL) and its relation to other anterolateral knee structures including the anterolateral capsule (ALC) and iliotibial band (ITB). The purpose of this cadaveric study was to investigate the effect of the ALL and ALC injuries on knee laxity with the iliotibial band (ITB) preserved in the anterior cruciate ligament (ACL)-injured knee. HypothesisThe ALL and ALC would contribute to knee joint stability during anterior translation and internal rotation of the tibia in an ACL-injured knee. Material and methodsFor 10 fresh-frozen cadaveric knees, we measured knee laxity with the following state of knee injuries with ITB preserved: (1) intact knee, (2) ACL-sectioned knee (ACL-), (3) additional sectioning of the ALL (ACL-/ALL-), and (4) additional sectioning of the ALC (ACL-/ALL-/ALC-). We did biomechanical measurements in internal-external rotation, anterior-posterior translation, and varus-valgus angulation for each condition at knee flexion angles of 0°, 30°, 60°, and 90°. ResultsAfter we sectioned the ALL (ACL-/ALL-), the mean IR at 0°, 30°, 60°, and 90° of knee flexion were significantly increased, compared to the intact knee (P=<0.001, <0.001, <0.001, and 0.002) and ACL- (p=<0.001, <0.001, <0.001, and 0.002). The additional transection of the ALC (ACL-/ALL-/ALC-) significantly increased IR laxity from the ACL-/ALL- at 30°, 60°, and 90° (p=0.005, 0.003, and 0.047). For anterior laxity, ACL-/ALL- resulted in significantly increased anterior laxity from the ACL- at 30° and 60° (P=0.003 and 0.019), and ACL-/ALL-/ALC- significantly increased anterior laxity even from the ACL-/ALL- at 30° and 60° (p=0.007 and 0.011). For varus laxity, ACL-/ALL- resulted in significantly increased varus laxity from both the intact knee and ACL- at 60° (P=0.004 and 0.007) and 90° (p=<0.001 and <0.001). ACL-/ALL-/ALC- resulted in significantly increased varus from ACL-/ALL- at 60° and 90° (p=<0.001 and 0.003). ConclusionThe anterolateral ligament and anterolateral capsule injuries in ACL-injured knees even with ITB preserved had a synergistic effect on knee laxity in the aspects of internal rotation, anterior translation, and varus angulation. Level of evidenceII, Controlled laboratory study.

Synergistic effect of the anterolateral ligament and capsule injuries on the knee laxity in anterior cruciate ligament injured knees: A cadaveric study

IntroductionThere is much controversy about the practical role of the anterolateral ligament (ALL) and its relation to other anterolateral knee structures including the anterolateral capsule (ALC) and iliotibial band (ITB). The purpose of this cadaveric study was to investigate the effect of the ALL and ALC injuries on knee laxity with the iliotibial band (ITB) preserved in the anterior cruciate ligament (ACL)-injured knee. HypothesisThe ALL and ALC would contribute to knee joint stability during anterior translation and internal rotation of the tibia in an ACL-injured knee. Material and methodsFor 10 fresh-frozen cadaveric knees, we measured knee laxity with the following state of knee injuries with ITB preserved: (1) intact knee, (2) ACL-sectioned knee (ACL-), (3) additional sectioning of the ALL (ACL-/ALL-), and (4) additional sectioning of the ALC (ACL-/ALL-/ALC-). We did biomechanical measurements in internal-external rotation, anterior-posterior translation, and varus-valgus angulation for each condition at knee flexion angles of 0°, 30°, 60°, and 90°. ResultsAfter we sectioned the ALL (ACL-/ALL-), the mean IR at 0°, 30°, 60°, and 90° of knee flexion were significantly increased, compared to the intact knee (p=<0.001, <0.001, <0.001, and 0.002) and ACL- (p=<0.001, <0.001, <0.001, and 0.002). The additional transection of the ALC (ACL-/ALL-/ALC-) significantly increased IR laxity from the ACL-/ALL- at 30°, 60°, and 90° (p=0.005, 0.003, and 0.047). For anterior laxity, ACL-/ALL- resulted in significantly increased anterior laxity from the ACL- at 30° and 60° (p=0.003 and 0.019), and ACL-/ALL-/ALC- significantly increased anterior laxity even from the ACL-/ALL- at 30° and 60° (p=0.007 and 0.011). For varus laxity, ACL-/ALL- resulted in significantly increased varus laxity from both the intact knee and ACL- at 60° (p=0.004 and 0.007) and 90° (p=<0.001 and<0.001). ACL-/ALL-/ALC- resulted in significantly increased varus from ACL-/ALL- at 60° and 90° (p=<0.001 and 0.003). ConclusionThe anterolateral ligament and anterolateral capsule injuries in ACL-injured knees even with ITB preserved had a synergistic effect on knee laxity in the aspects of internal rotation, anterior translation, and varus angulation. Level of evidenceII, Controlled laboratory study.

Biomechanical Assessment of Knee Laxity After a Novel Posterolateral Corner Reconstruction Technique

Background: Different techniques to restore knee stability after posterolateral corner (PLC) injury have been described. The original anatomic PLC reconstruction uses 2 separate allografts to reconstruct the PLC. Access to allograft tissue continues to be a significant limitation of this technique, which led to the development of a modified anatomic approach utilizing a single autologous semitendinosus graft fixed on the tibia with an adjustable suspensory loop to enable differential tensioning of the PLC components. Purpose/Hypothesis: The purpose of this study was to compare the modified anatomic technique with the original anatomic reconstruction in terms of varus and external rotatory laxity in a cadaveric biomechanical model. The hypothesis was that both techniques would restore varus and external rotatory laxity after a simulated complete PLC injury. Study Design: Controlled laboratory study. Methods: Eight pairs of fresh-frozen cadaveric knee specimens were tested to compare the 2 techniques. Varus and external tibial rotation laxity of the knee were measured while applying 10-N·m varus and 5-N·m external rotatory torques at 0°, 30°, 60°, and 90° of flexion. These measurements were tested under 3 conditions: (1) intact fibular collateral ligament, popliteal tendon, and popliteofibular ligament; (2) complete transection of the fibular collateral ligament, popliteal tendon, and popliteofibular ligament; (3) after PLC reconstruction with either the modified (n = 8) or the original (n = 8) technique. Results: After PLC reconstruction, varus laxity was restored with no statistically significant differences from the intact condition after both reconstruction techniques. Similar outcomes were observed for external rotation in extension; however, in terms of the external rotation limit with respect to the intact joint, significant reductions of mean ± SD 4.1°± 6.3° (P = .036) and 5.1°± 6.6° (P = .016) were recorded with the modified technique at 60° and 90° of flexion, respectively. No significant effect was observed on the neutral flexion kinematics from 0° to 90° of flexion, and no significant differences were observed between reconstructions (P = .222). Conclusion: Both PLC reconstruction techniques restored the normal native varus as compared with the intact knee. Although the modified technique constrained end-range external rotation at 60° and 90° of flexion, no differences were noted with neutral flexion kinematics. Care should be taken when tensioning in the modified technique so that the tibia is in a neutral position to avoid overconstraining the knee. Clinical Relevance: The modified technique may prove useful in situations where there are limited graft options, particularly where allografts are not available or are restricted.

Ultrasonographic Measurement of Elbow Varus Laxity With a Sequential Injury Model of the Lateral Collateral Ligament-Capsular Complex.

Background:There is no consensus how to determine the varus laxity due to the LCL injury using the ultrasonography. There is a risk of lateral collateral ligament injury during or after arthroscopic extensor carpi radialis brevis release for tennis elbow. The equator of the radial head has been suggested as a landmark for the safe zone to not increase this risk; however, the safe zone from the intra-articular space has not been established.Hypothesis:Increased elbow varus laxity due to lateral collateral ligament–capsular complex (LCL-cc) injury could be assessed reliably via ultrasound.Study Design:Descriptive laboratory study.Methods:Eight cadaveric elbows were evaluated using a custom-made machine allowing passive elbow flexion under gravity varus stress. The radiocapitellar joint (RCJ) space was measured via ultrasound at 30° and 90° of flexion during 4 stages: intact elbow (stage 0), release of the anterior one-third of the LCL-cc (stage 1), release of the anterior two-thirds (stage 2), and release of the entire LCL-cc (stage 3). Two observers conducted the measurements separately, and the mean RCJ space in the 3 LCL-cc injury models (stages 1-3) at both flexion angles was compared with that of the intact elbow (stage 0). We also compared the measurements at 30° versus 90° of flexion.Results:At 30° of elbow flexion, the RCJ space increased 2 mm between stages 0 and 2 (95% confidence interval [CI], 1-3 mm; P < .01) and 4 mm between stages 0 and 3 (95% CI, 2-5 mm; P < .01). At 90° of elbow flexion, the RCJ space increased 1 mm between stages 0 and 2 (95% CI, 1-2 mm; P < .01) and 2 mm between stages 0 and 3 (95% CI, 2-3 mm; P < .01).Conclusion:Elbow varus laxity under gravity stress can be reliably assessed via ultrasound by measuring the RCJ space.Clinical Relevance:Because ultrasonographic measurement of the RCJ space can distinguish the increasing varus laxity seen with release of two-thirds or more of the LCL-cc, the anterior one-third of the LCL-cc, based on the diameter of the radial head, can be considered the safe zone in arthroscopic extensor carpi radialis brevis release for tennis elbow.

STUDY ON FUNCTIONAL OUTCOME OF TIBIAL PLATEAU FRACTURES TREATED WITH LOCKING COMPRESSION PLATE

Proximal tibial fractures, one of the commonest intra articular fractures. Incidence of these fractures is increasing due to road trafc accidents. At the same time surgical treatment options for the same are also being modied continuously. Any fracture around the weight bearing joint like knee joint is of paramount importance as it would result in signicant morbidity. Hence the treatment of proximal tibial fractures has become a challenge for the orthopaedic surgeons. Methods: During the study period 31 patients were treated with locking compression plate on lateral side through anterolateral approach for varying types of tibial plateau fractures. Out of 31, 28 patients were available at nal follow up. The functional and radiological outcome assessed with Rasmussen scoring system. At the end of study stability of the knee joint assessed with standard stability tests. Results: Most of the patients were sustained injury following major road trafc accidents and most of them were males. At nal follow up the functional outcome was excellent in 65 % of patients and good to fair in 35% of patients. No patient had poor functional outcome, though 10% of patients had poor radiological outcome. At the end of study 3 patients had posterior laxity, 2 patients had lateral meniscal injury and 4 patients had varus laxity. Conclusion: The functional outcome of tibial plateau fractures treated with single lateral locking compression plate was satisfactory in all our patients. All patients had acceptable clinical outcome though few patients had poor radiological outcome. We found 32% of patients with instability at the end of our study

Characteristic kinematics of floor-sitting activities after posterior-stabilized total knee arthroplasty determined using model-based shape-matching techniques

BackgroundDetailed kinematics of floor-sitting activities after total knee arthroplasty (TKA) have not been well explored. Knee kinematics of cross-legged sitting, seiza-sitting, and side-sitting after TKA were examined to clarify the differences in tibiofemoral kinematics of each activity. MethodsSubjects were 40 knees in 20 osteoarthritic patients who underwent bilateral TKA with a high-flexion fixed-bearing posterior-stabilized prosthesis. Dynamic radiographs of floor-sitting activities were taken, and the knee kinematics were compared among the three activities. The patients were also divided into two groups (possible/easy group and impossible/no-try group) for each activity, and group comparisons were conducted. ResultsThe maximum implant flexion angle was significantly greater in seiza-sitting. In valgus/varus rotation, seiza-sitting demonstrated neutral rotation, while cross-legged sitting showed varus of about 10°, and side-sitting exhibited valgus. In tibial internal/external rotation, seiza-sitting demonstrated a constant rotational angle, while cross-legged sitting showed tibial internal rotation with flexion, and side-sitting exhibited tibial external rotation with flexion. The kinematic pathway during deep flexion illustrated the medial pivot pattern in cross-legged sitting, a small amount of bicondylar rollback in seiza-sitting, and the weak lateral pivot pattern in side-sitting. A greater flexion angle was the important factor for the performance of each floor-sitting activity followed by varus laxity at 10° knee flexion. ConclusionsThis study successfully revealed characteristic kinematic patterns of TKA knees in three floor-sitting activities. Obtaining a greater knee flexion with adequate lateral laxity is the key to enhancing postoperative floor-sitting activities.

Feasibility and technique of ultrasound traumatic elbow lesion assessment

IntroductionThe present study aimed to describe the technique of ultrasound traumatic elbow lesion assessment performed by an orthopedic surgeon. MethodsNine patients were included in a single-center study. Clinical examination assessed pain, ranges of elbow motion, neurovascular status and elbow ligament testing. Ultrasound was associated to radiography between days 7 and 15, screening for lesions of the bone, medial ligament (in 30-90° flexion), lateral ligament (elbow at 90° in cobra position) and epitrochlear and epicondylar muscle insertions. Ultrasound scanning time and echogenicity were assessed. ResultsFour radial head osteochondral fractures were detected on ultrasound in addition to the 4 fractures seen on radiography, without significant difference (p=0.071). Clinical examination found 2 cases of valgus laxity and 5 of varus laxity. Ultrasound, performed blind to radiography, found 1 medial collateral ligament anterior bundle lesion (in 1 of the 2 patients with valgus laxity) and 4 lateral collateral ligament ulnar bundle lesions (in 4 of the 5 patients with varus laxity). There were no epicondylar or epitrochlear tendon lesions. Scanning time decreased significantly over the study period, from a mean 30minutes in the first 5 cases to a mean 24.8minutes in the last 5 (p=0.046). Three patients could not be put in the cobra position, and 3 showed poor echogenicity. DiscussionUltrasound assessment of traumatic elbow lesions could be performed by an orthopedic surgeon on a well-defined protocol. Lesions on ultrasound matched clinical symptomatology. Inter- and intra-observer reproducibility remain to be assessed. Level of evidenceIV.

Greater postoperative relatively medial loose gap at 90° of flexion for varus knees improves patient-reported outcome measurements in anatomical bi-cruciate retaining total knee arthroplasty

BackgroundThe purpose of the present study was to measure the intraoperative joint gap using tensor device and pre- and, postoperative joint stability at 0, 30 and 90° of flexion using stress radiography and to identify whether these factors influence patient-reported outcome measurement (PROM) in anatomical bi-cruciate retaining (BCR) knee arthroplasty (TKA). MethodsFifty-three knees with preoperative varus osteoarthritis of the knee underwent anatomical BCR TKA with oblique three-degree angle femorotibial joint line. The intraoperative medial and lateral joint gap using a tensor device and gap difference (lateral minus medial; varus laxity) were also calculated. Postoperative joint stability was measured using stress radiographs. PROM was also evaluated at 1.5 years postoperatively. The effect of intraoperative and postoperative joint stabilities on PROMs were analyzed using Spearman's rank correlation analysis. ResultsIntraoperative greater difference between medial joint gap at 140° and 0° of flexion showed significant positive correlation with postoperative function of patellofemoral joint. Intraoperative varus laxity at extension improved postoperative symptoms in 2011 Knee Society Score (2011 KSS); greater postoperative lateral stability at 30 and 90° of flexion with the varus stress test was associated with the better patient expectation in 2011 KSS. Postoperative medial laxity at 90° of flexion with the valgus stress test positively correlated with the patient expectation and satisfaction in 2011 KSS. ConclusionsSurgeons should notice that the postoperative lateral stability and medial laxity at 90° of flexion improved PROM in anatomical BCR TKA.

Retrieval Analysis of Cruciate-Retaining and Posterior-Stabilized Total Knee Arthroplasty and Correlations to Laxity and Wear

BackgroundTotal knee arthroplasty (TKA) with posterior-stabilized (PS) or posterior cruciate-retaining (CR) implants has high success rates and survivorship. However, it is uncertain how laxity and constraint are associated with long-term polyethylene wear under physiological conditions. MethodsTo answer this question, we measured the laxity patterns of 47 harvested cadaver specimens with primary TKAs in a custom knee-testing machine at full extension and at 30°, 60°, and 90° of flexion. The wear patterns of the tibial inserts were assessed using a semiquantitative method which is a modified approach of that proposed by Hood et al in 1983. ResultsStatistical analysis found that the PS TKA cohort had a statistically significant increase in varus laxity at 60° and 90° of flexion, as well as total coronal laxity at 60° of flexion when compared to the CR cohort. Furthermore, analysis demonstrated a significant correlation between increased PS coronal laxity and increased tibial wear, a trend that was not seen in the CR specimens. ConclusionOur findings suggest that greater laxity in flexion after primary TKA may increase the wear realized over time and that PS TKAs may be more susceptible due to the loss of support the PCL affords to the flexion space. Whether a CR or PS TKA is used, surgeons need to avoid the pitfalls that may create greater flexion laxity during the procedure to optimize long-term polyethylene wear.

Posterolateral corner reconstruction in combined injuries of the knee: Improved stability with Larson's fibular sling reconstruction and comparison with LaPrade anatomical reconstruction

BackgroundThe goal of this prospective cohort study was to present the clinical results of a two-year follow-up of a Larson's posterolateral corner reconstruction (fibular sling) in patients with symptomatic instability of the knee. These data were compared with data of an anatomical reconstruction of the posterolateral corner as described by LaPrade et al. (combined tibial tunnel and fibular sling) [1]. MethodsEleven patients underwent a Larson's posterolateral corner reconstruction. Cruciate ligament ruptures were reconstructed if present. Multiple subjective knee outcome scores (VAS satisfaction score, Tegner, Lysholm, Noyes score, and IKDC subjective knee score) were obtained pre-operatively and two years after surgery. Laxity of the joint was measured using bilateral varus stress radiographs. ResultsAll patients had concomitant ACL or PCL surgery. VAS satisfaction, the Tegner, Noyes and the IKDC subjective knee score all improved significantly. Median varus laxity of the injured knee on varus stress radiographs improved significantly from 6.2° (3.1–10.1) to 3.9° (1.1–5.7), p = .0076. Post-operative varus laxity did not return to the level of the uninjured knee: 2.7° (1–5.7), p = .028. In comparison with our data on the reconstruction technique according to LaPrade, no statistically significant differences in clinical outcome were observed. ConclusionReconstruction of the posterolateral corner in combined injuries of the knee using a Larson fibular sling technique results in improved varus stability but not to the level of the uninjured knee. Functional knee scores improved significantly.We found no differences in functional and radiological outcome between the Larson's fibular sling reconstruction and LaPrade anatomical reconstruction. Level of evidenceIV

Coronal tibiofemoral subluxation is a risk factor for postoperative overcorrection in high tibial osteotomy

BackgroundSevere tibiofemoral (TF) subluxation > 10 mm is a contraindication for high tibial osteotomy (HTO). However, the relationship between the degree of preoperative TF subluxation at < 10 mm and postoperative radiographic/clinical outcomes remains unclear. MethodsSixty-seven patients who underwent open wedge HTO with a planned postoperative mechanical femorotibial angle (mFTA) of three degrees valgus were retrospectively studied. The minimal subluxation (MIN) group included 39 patients with TF subluxation < 5 mm, while the moderate subluxation (MOD) group included 28 patients with TF subluxation of five to 10 mm. The preoperative and one-year postoperative mFTA, TF subluxation, medial proximal tibial angle (MPTA), joint line convergence angle (JLCA), preoperative Kellgren-Lawrence (K–L) grade and varus-valgus laxity were evaluated. Clinical scores and pain visual analogue scale (VAS) were also analyzed. ResultsThe mean preoperative TF values in the MIN and MOD groups were 3.1±1.0 mm and 6.7±1.6 mm (mean±standard deviation, p < 0.001), respectively, with no significant difference in K–L grades. The MIN group demonstrated a significantly smaller varus preoperative mFTA (p < 0.001), larger MPTA (p = 0.011), smaller JLCA (p = 0.004), and less varus laxity (p = 0.023). Postoperative TF subluxation, MPTAs, and JLCAs did not differ significantly between the two groups, while the postoperative mFTA was significantly different (p = 0.001), with unintended overcorrection in the MOD group. No significant difference in clinical scores and VAS were observed. ConclusionsAfter HTO, compared to patients with TF subluxation < 5 mm, patients with TF subluxation of five to 10 mm were more likely to demonstrate unintended valgus overcorrection on one-year postoperative radiography.

L’alignement cinématique d’une prothèse totale de genou reproduit mieux le roulement-glissement et la laxité que l’alignement mécanique : une étude cadavérique comparative

BackgroundA growing body of evidence supports that kinematically aligned (KA) total knee arthroplasty (TKA) provides superior clinical outcomes and satisfaction than mechanically aligned (MA) TKA. In theory, KA TKA would restore knee kinematics closer to the native condition than MA TKA, but the current biomechanical evidence is lacking. HypothesisKA TKA would restore knee biomechanics to the native condition better than MA TKA. MethodsSeven pairs of cadavers were tested. For each pair, one knee was randomly assigned to KA TKA and the other to MA TKA. During KA TKA, the sizes of femur and tibia resections were equivalent to implant thickness to align with the patient-specific joint line. MA TKA was performed using conventional measured resection techniques. All specimens were mounted on a customized knee-testing system and digitized. Knee motions measured during flexion included rollback, axial tibiofemoral rotation, and laxities, specifically varus-valgus laxity, anterior-posterior translation, and internal-external rotation. ResultsThe pattern of knee motion following KA TKA was similar to the native knee. However, following MA TKA, both medial and lateral rollback and tibiofemoral axial rotation were decreased relative to those of the native knee. Valgus laxity was restored only after KA TKA, whereas varus laxity was restored only after MA TKA. Anterior translation was increased regardless of the alignment strategy. In addition, rotational laxities were restored after KA TKA, but external rotation laxity increased after MA TKA. ConclusionKA TKA restores femoral rollback and laxity to the native condition better than MA TKA. KA TKA may enhance functional performance and provide a more normal knee sensation. Level of evidenceII, Controlled laboratory study.