Correlation between the rotational degree of the dial test and arthroscopic and physical findings in posterolateral rotatory instability

Rater agreement reliability of the dial test in the ACL-deficient knee

Background

Posterolateral rotatory instability (PLRI) of the knee can easily be missed, because attention is paid to injury of the cruciate ligaments. If left untreated this clinical instability may persist after reconstruction of the cruciate ligaments and may put the graft at risk of failure. Even though the dial test is widely used to diagnose PLRI, no validity and reliability studies of the manual dial test are yet performed in patients. This study focuses on the reliability of the manual dial test by determining the rater agreement.

Methods

Two independent examiners performed the dial test in knees of 52 patients after knee distorsion with a suspicion on ACL rupture. The dial test was performed in prone position in 30°, 60° and 90° of flexion of the knees. ≥10° side-to-side difference was considered a positive dial test. For quantification of the amount of rotation in degrees, a measuring device was used with a standardized 6 Nm force, using a digital torque adapter on a booth. The intra-rater, inter-rater and rater-device agreement were determined by calculating kappa (κ) for the dial test.

Results

A positive dial test was found in 21.2% and 18.0% of the patients as assessed by a blinded examiner and orthopaedic surgeon respectively. Fair inter-rater agreement was found in 30° of flexion, κ_F = 0.29 (95% CI: 0.01 to 0.56), p = 0.044 and 90° of flexion, κ_F = 0.38 (95% CI: 0.10 to 0.66), p = 0.007. Almost perfect rater-device agreement was found in 30° of flexion, κ_C = 0.84 (95% CI: 0.52 to 1.15), p < 0.001. Moderate rater-device agreement was found in 30° and 90° combined, κ_C = 0.50 (95% CI: 0.13 to 0.86), p = 0.008. No significant intra-rater agreement was found.

Conclusions

Rater agreement reliability of the manual dial test is questionable. It has a fair inter-rater agreement in 30° and 90° of flexion.

Dial Test: Unrecognized Predictor of Anterior Cruciate Ligament Deficiency

PURPOSE

To evaluate the effect of isolated anterior cruciate ligament (ACL) injury on tibial external rotation as measured by the dial test.

METHODS

Twenty-seven consecutive patients scheduled to undergo a primary ACL reconstruction were prospectively evaluated. Physical examination and magnetic resonance imaging findings were analyzed to exclude multiligamentous injury. The dial test was performed with the patient under anesthesia with a goniometer on both the affected and unaffected knees at 30° and 90°. Intraoperatively, the arthroscopic posterolateral corner gaps before reconstruction and after reconstruction were documented. Postoperatively, the dial test was again performed on both knees at 30° and 90°.

RESULTS

At 30°, there was a significantly larger dial test result in the affected knee before ACL reconstruction compared with after ACL reconstruction (27.6° vs 21.0°, P < .0001) and compared with the unaffected knee (27.6° vs 20.5°, P < .0001), but this difference was eliminated after reconstruction (21.0° vs 20.5°, P = .5089). At 90°, there was a significantly larger dial test result in the affected knee before ACL reconstruction compared with after ACL reconstruction (27.6° vs 21.1°, P < .0001) and compared with the unaffected knee (27.6° vs 20.9°, P < .0001), with this difference was eliminated after reconstruction (21.1° vs 20.9°, P = .7831).

CONCLUSIONS

Incompetence of the ACL accounts for nearly 7° of tibial external rotation found by the dial test. During examination of an injured knee, if the dial test is positive, an isolated ACL injury should not be excluded. Findings of the dial test should thus be interpreted with caution in the setting of ACL injury.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

The necessity of clinical application of tibial reduction for detection of underestimated posterolateral rotatory instability in combined posterior cruciate ligament and posterolateral corner deficient knee

PURPOSE

The purpose of this study was to evaluate the usefulness of tibial reduction during dial test for clinical detection of underestimated posterolateral rotatory instability (PLRI) in combined posterior cruciate ligament (PCL)-posterolateral corner (PLC) deficient knee in terms of external rotation laxity and clinical outcomes.

METHODS

Twenty-one patients who classified as grade I PLRI using dial test with subluxated tibia, but classified as grade II with tibial reduction evaluated retrospectively. The mean follow-up was 39.3 months (range 24-61 months). Each patient was evaluated by the following variables: posterior translation and varus laxity on radiograph, KT-1000 arthrometer, dial test (reduced and subluxated position), International Knee Documentation Committee, Orthopädische Arbeitsgruppe Knie scoring system and Tegner activity scale.

RESULTS

There were significant improvements in posterior tibial translation (8.6 ± 2.0 to 2.1 ± 1.0 mm; P < 0.001), varus laxity (3.3 ± 1.3 to 1.4 ± 0.5 mm; P < 0.001) and external rotation (13.2° ± 0.8° to 3.6° ± 1.1° at 30°, 13.3° ± 0.9° to 3.6° ± 0.9° at 90°; P < 0.001). The clinical scores were improved significantly at the last follow-up (P < 0.001). The external tibial rotation during dial test with tibial reduction increased from 6.8° ± 0.9 to 13.2° ± 0.8° at 30° of knee flexion, from 7.0° ± 0.8° to 13.3° ± 0.9° at 90° (P < 0.001).

CONCLUSIONS

The clinical application of reduction of posteriorly subluxated tibia during the dial test was essential for an appropriate treatment of underestimated PLRI in combined PCL-PLC deficient knee.

LEVEL OF EVIDENCE

Retrospective case series, Level IV.

Clinical, Functional, and Morphological Evaluations of Posterior Cruciate Ligament Reconstruction With Remnant Preservation: Minimum 2-Year Follow-up

BACKGROUND

Numerous posterior cruciate ligament (PCL) reconstruction techniques have evolved and have revealed satisfactory outcomes; however, the optimal operative method for PCL reconstruction remains controversial.

HYPOTHESIS

Transtibial PCL reconstruction with a remnant preservation technique would result in successful clinical, radiological, functional, and morphological outcomes. In addition, it was hypothesized that the results of combined PCL and posterolateral corner (PLC) reconstruction would be comparable with those of isolated PCL reconstruction.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 168 patients who underwent arthroscopic PCL reconstruction with or without reconstruction of the PLC between March 2006 and June 2011 were retrospectively reviewed. Ninety-two patients who met the inclusion criteria were enrolled, and 47 of 92 patients who underwent combined PCL and PLC reconstruction were evaluated as a subgroup. The PLC was reconstructed using the single fibular sling method. The patients were assessed by means of the Lysholm score, International Knee Documentation Committee (IKDC) subjective knee score, and Tegner activity score. Stability was evaluated using a KT-2000 arthrometer and Telos device. Proprioception was assessed using the Biodex System. Follow-up magnetic resonance imaging (MRI) was performed in 34 patients, and second-look arthroscopic surgery was conducted in 36 patients.

RESULTS

The minimum follow-up duration was 24 months in all patients. Clinical outcomes and posterior instability improved significantly. The mean Lysholm score improved from 56.7 ± 7.1 to 89.3 ± 7.3, the mean IKDC subjective knee score improved from 53.3 ± 9.6 to 86.2 ± 6.1, and the mean Tegner activity score was 2.5 ± 0.8 preoperatively and 5.1 ± 1.3 postoperatively (all P < .001). The mean side-to-side difference on posterior stress radiography with the Telos device improved significantly, decreasing from 12.1 ± 2.5 mm to 2.7 ± 1.3 mm (P < .001). The mean side-to-side difference on varus stress radiography was reduced from 5.9 ± 0.8 mm preoperatively to 1.3 ± 1.0 mm after combined PCL and PLC reconstruction (P < .001). Postoperative proprioception recovered to a level similar to that of the uninvolved side, and MRI and second-look arthroscopic surgery showed a high rate of complete healing and synovialization in patients who underwent either isolated PCL reconstruction or combined PLC and PCL reconstruction.

CONCLUSION

Transtibial PCL reconstruction with remnant preservation resulted in satisfactory clinical, functional, radiological, and morphological outcomes. The results of combined posterolateral rotatory instability were comparable with those for isolated PCL reconstruction with adequate PLC reconstruction.

Posterolateral corner reconstruction using the single fibular sling method for posterolateral rotatory instability of the knee

BACKGROUND

Recently, posterolateral corner (PLC) reconstruction techniques have been developed based on an anatomic study of cadaveric dissections. However, the best operative method for various anatomic reconstructions remains controversial.

HYPOTHESIS

The anatomic single fibular sling method for PLC reconstruction would be sufficiently strong to control posterolateral rotatory instability without an additional tibial sling.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

This retrospective cohort study analyzed 60 knees in 60 patients who underwent anatomic PLC reconstruction using the single fibular sling method with a tibialis anterior allograft, with a minimum follow-up period of 2 years. Ninety percent of the patients had concomitant reconstruction of one or both cruciate ligaments. Preoperative and postoperative dial test, varus stress test, and subjective clinical outcomes including Lysholm score, International Knee Documentation Committee (IKDC) subjective scores, and stress radiographs, including varus and posterior stress, were compared. In addition, intraoperative arthroscopic findings were analyzed.

RESULTS

The mean length of clinical follow-up was 35.6 months (range, 24-65 months). Forty-two (70%) patients showed no rotational instability postoperatively. Varus laxity improved, with 96.7% of the patients assessed as grade 0 or 1. The mean side-to-side difference in varus stress test was reduced from 2.32 ± 1.33 mm preoperatively to 0.37 ± 1.48 mm postoperatively. Posterior stress radiography in combined posterior cruciate ligament reconstruction showed a mean posterior tibial translation of 14.7 ± 2.83 mm preoperatively and 4.06 ± 1.40 mm at final follow-up. The Lysholm and IKDC subjective scores improved from 52 ± 6.7 to 87.7 ± 12.3 and from 44.8 ± 6.3 to 77.6 ± 14.2 (P < .001), respectively. There were no significant differences in clinical outcome or varus laxity between isolated PLC and combined injuries.

CONCLUSION

Anatomic PLC reconstruction using a single fibular sling method is an effective and relatively simple procedure for most patients with posterolateral rotatory instability, with the exception of those with severe multiple injuries.

Validity of a novel arthroscopic test to diagnose posterolateral rotational instability of the knee joint: the lateral gutter drive-through test

PURPOSE

The purpose of this study was to assess the validity of a newly developed arthroscopic test, termed the lateral gutter drive-through (LGDT) test, to diagnose posterolateral rotational instability (PLRI) of the knee joint.

METHODS

Between October 2009 and February 2012, 115 consecutive patients were enrolled into this prospective diagnostic study. The dial test was used as the gold standard for diagnostic reference. According to the dial test, the patients were divided into a study group (35 patients) and a control group (80 patients). The LGDT test was performed on all patients during arthroscopic surgery. The sensitivity and specificity of the LGDT test were calculated. Sensitivities were also calculated in subgroups defined by injury patterns and extents of tibial external rotational instability.

RESULTS

The sensitivity and specificity of the LGDT test were calculated as 91.4% and 93.8%, respectively. In subgroup analyses the sensitivity of detection for acute PLRI was 90% versus 92% in chronic cases (P = .849). Popliteus femoral "peel-off" lesions were detected with a sensitivity of 100% versus 87.0% in cases of non-peel-off lesions (P = .536). The sensitivity of detecting isolated external rotational instability versus combined instability (rotational and varus) was 90.5% versus 92.8% (P = .805). The sensitivity of the LGDT test was correlated with the extent of tibial external rotational instability (P < .001).

CONCLUSIONS

This study showed that the LGDT test is a reliable method and can be used for diagnosing PLRI of the knee joint. The highest sensitivity was observed in patients with the femoral peel-off injury pattern. The sensitivity of the LGDT test was correlated with the extent of tibial external rotational instability and was significantly higher in patients with an increase in tibial external rotation by more than 10°.

LEVEL OF EVIDENCE

Level I, diagnostic study: testing of previously developed criteria in a series of consecutive patients.

Evaluation of outcomes in conservatively managed concomitant Type A and B posterolateral corner injuries in ACL deficient patients undergoing ACL reconstruction

INTRODUCTION

There is paucity of literature regarding the outcomes of ACL reconstruction in ACL deficient knees with concomitant Type A and Type B PLC injuries.

MATERIALS AND METHODS

A total of 102 patients undergoing isolated ACL reconstruction for an ACL injury were evaluated prospectively in this study. The patients with divided into three groups: group A with isolated ACL injury, group B1 with concomitant Type A PLC injury and group B2 with concomitant Type B PLC injury. The associated PLC injury in all these patients was managed conservatively. Outcome assessment was based on IKDC scores measured preoperatively and at last follow up visits.

RESULTS

The mean age of the patients was 25.33 years (16-38 years) with 95 males and seven females. The average follow up was almost 2.5 years (13-46 months). Group A had 88 patients while groups B1 and B2 had six and eight patients respectively. The preoperative IKDC scores were comparable for all the groups. The follow up IKDC scores were similar (statistically insignificant, p value: 0.421) for group A and group B1. Group B2 had poorer follow up IKDC scores as compared to group A and this result was found to be statistically significant (p value: 0.0001).

CONCLUSION

Conservative management of a concomitant Type B PLC injury adversely affects the outcomes of ACL reconstruction in these patients. Type A PLC injuries, on the other, do well without surgery and can be left as such even when associated with a concomitant ACL tear.

LEVEL OF EVIDENCE

Level 2.

Can wedge osteotomy correct depression of the lateral tibial plateau mimicking posterolateral rotatory knee instability?

BACKGROUND

The literature suggests rotatory knee instability (pseudolaxity) can be associated with depressions of the lateral tibial plateau in patients despite an intact arcuate ligament complex. Correcting this bone deformity by an open-wedge osteotomy of the lateral tibia plateau, elevating the depressed bone may restore knee stability.

QUESTIONS/PURPOSES

We therefore asked whether: (1) knee stability is restored after this procedure; (2) Lysholm functional scores improve after this treatment; and (3) the limb alignment changes.

PATIENTS AND METHODS

We retrospectively evaluated 12 patients who underwent a subchondral open-wedge osteotomy of the lateral tibial plateau combined with a knee arthroscopic procedure for the treatment of a knee rotational instability secondary to a lateral compartment bone deficit between 2000 and 2007. Eleven patients with a mean age of 35 years were available for followup at a minimum of 2 years (average, 5.4 years; range, 2-9 years). Preoperatively and at last followup, patients were clinically and radiographically evaluated by the Lysholm score and with comparative knee radiographs. Complications were recorded.

RESULTS

At last followup all patients rated their knees as stable. All osteotomies healed uneventfully. The Lysholm score improved from 62 to 87. Followup radiographs showed no changes in the femorotibial axis as result of the osteotomy.

CONCLUSIONS

Patients with chronic depression of the posterolateral tibial plateau may exhibit symptoms of posterolateral knee instability, a sort of pseudolaxity. In these patients, an open-wedge osteotomy of the lateral tibia plateau, elevating the depressed bone, and tensioning posterolateral structures improves this secondary posterolateral knee instability.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Comparison between Single and Dual Femoral Fixation for Anterior Cruciate Ligament Reconstruction with a Hamstring Autograft

Purpose

The purpose of this study was to evaluate dual fixation with different fixation mechanisms, determine the advantages, and compare the outcomes between single and dual femoral fixation.

Materials and Methods

From April 2004 to September 2007, 19 patients who received single femoral fixation and 22 patients who received dual femoral fixation were enrolled in the study. Single femoral fixation was performed using a cross-pin expansion mechanism. Dual femoral fixation was performed using a cross-pin expansion mechanism and an EndoButton CL loop suspensory mechanism.

Results

No significant differences were found in the incidence of cross-pin problems between the two groups (p=0.35-0.83) or in the stability assessment using a KT-2000 arthrometer and pivot shift test preoperatively (p=0.79 and 0.77, respectively) or postoperatively (p=0.89 and 0.75, respectively). In addition, no significant differences were detected between the two groups in the Lysholm, Tegner activity, or International Knee Documentation Committee knee scores preoperatively (p=0.07-0.47) or postoperatively (p=0.15-0.89).

Conclusions

This study showed that dual fixation with different fixation mechanisms was not advantageous over the single fixation mechanism. Outcomes using the dual femoral fixation mechanism were not superior to those using the single femoral fixation mechanism.

Comparative outcome analysis of malpositioned and properly positioned fixation groups after hamstring autograft ACL reconstruction with femoral cross-pin fixation

Anterior cruciate ligament (ACL) reconstruction using soft tissue grafts has been gaining in popularity. Cross-pin fixation is used frequently, and its principle of fixation is an expansion mechanism. However, some malpositioned cases have been reported, and these malpositions may cause poor outcomes. Our aim was to compare the stability and clinical results between malpositioned and properly positioned cases. From November 2003 to December 2007, 41 patients were enrolled in this study. We divided these patients into malpositioned and properly positioned subgroups. The malpositioned group was defined by the presence of any finding among the following: posteriorly directed cross-pin to the posterior condylar line upon axial imaging, breakage upon coronal imaging, and outside-positioned cross-pin to the distal femoral posterior cortex upon sagittal imaging. We compared clinical and stability results between the two groups. Twenty-three patients were included in the properly positioned group, and 18 in the malpositioned group. The intra-class correlation coefficient for the intra- and inter-rater agreement ranged from 0.88 to 0.93 (0.88, 0.91, 0.91, and 0.93). No significant differences were found between the two groups in the stability assessment using a KT-2000 arthrometer and pivot-shift test (P=0.93 and 0.78, respectively). No significant differences were found between the two groups in the clinical knee scales (Ps=0.08-0.93). This study showed that some malpositions can occur with cross-pin femoral fixation. However, we obtained comparable good outcomes regardless of the fixation strategies if the initial fixation was correct.