Remapping motion across modalities: tactile rotations influence visual motion judgments

Multisensory interactions between haptics and vision remain poorly understood. Previous studies have shown that shapes, such as letters of the alphabet, when drawn on the skin, are differently perceived dependent upon which body part is stimulated and on how the stimulated body part, such as the hand, is positioned. Another line of research within this area has investigated multisensory interactions. Tactile perceptions, for example, have the potential to disambiguate visually perceived information. While the former studies focused on explicit reports about tactile perception, the latter studies relied on fully aligned multisensory stimulus dimensions. In this study, we investigated to what extent rotating tactile stimulations on the hand affect directional visual motion judgments implicitly and without any spatial stimulus alignment. We show that directional tactile cues and ambiguous visual motion cues are integrated, thus biasing the judgment of visually perceived motion. We further show that the direction of the tactile influence depends on the position and orientation of the stimulated part of the hand relative to a head-centered frame of reference. Finally, we also show that the time course of the cue integration is very versatile. Overall, the results imply immediate directional cue integration within a head-centered frame of reference.     

Fluorescein angiographic findings and clinical features in Fuchs’ uveitis

Fuchs’ uveitis is very often diagnosed with substantial delay, which is at the origin of deleterious effects such as unnecessary treatment and its consequences. The aim of this study was to analyse the type and frequency of posterior inflammatory and fluorescein angiographic signs in Fuchs’ uveitis in conjunction with other clinical signs. Patients seen at the Centre for Ophthalmic Specialised Care (COS) in Lausanne and the Memorial A. de Rothschild, Clinique Générale-Beaulieu in Geneva between 1995 and 2008 with the diagnosis of Fuchs’ uveitis and who had undergone a fundus fluorescein angiography (FFA) were analysed. In addition to FFA signs, the data collected included age, gender, initial and final visual acuities, clinical findings at presentation, mean diagnostic delay and ocular complications. Between 1995 and 2008, 105 patients seen in our centres in Lausanne and Geneva were diagnosed with Fuchs’ uveitis. Forty of them (38.1%) had undergone at least one FFA. One patient was excluded because of a concomittant diagnosis of multiple sclerosis. In 28 of 39 patients (71.2%) diagnosis was not reached at presentation with a mean diagnosis delay of 3.67 ± 4.86 years (range: 1 month–24 years). The original erroneous diagnosis was intermediate uveitis in 16 patients (57.1%), posterior uveitis in two patients (7.1%), panuveitis in four patients (14.3%) and anterior granulomatous uveitis in six patients (21.4%). Fluorescein angiography demonstrated the presence of disc hyperfluorescence in 43/44 eyes (97.7%), sectorial peripheral retinal vascular leaking in 6/44 eyes (13.6%) and cystoid macular oedema in 4/44 eyes (9.1%), all of which were seen in eyes having undergone cataract surgery. Fuchs’ uveitis was bilateral in 5/39 patients (12.8%). The most frequent clinical signs were vitritis in 42/44 eyes (95.5%), stellate keratic precipitates in 41 eyes (93.2%), posterior subcapsular opacities or cataract in 19 eyes (43.2%), and heterochromia in 19 eyes (43.2%). Fuchs’ uveitis is a largely underdiagnosed uveitis, probably because the predominant vitreous involvement is ignored by many ophthalmologists. In addition, the nearly constant inflammatory fluorescein angiography findings reported here such as disc hyperfluorescence and, more rarely, peripheral retinal vascular leaking, are not well known and are not usually associated with Fuchs’ uveitis but represent an additional factor leading to misdiagnosis. These findings need to be recognised in order to reduce diagnostic delay.     

ACL mismatch reconstructions: influence of different tunnel placement strategies in single-bundle ACL reconstructions on the knee kinematics

To evaluate the influence of tibial and femoral tunnel position in ACL reconstruction on knee kinematics, we compared ACL reconstruction with a tibial and femoral tunnel in anteromedial (AM-AM reconstruction) and in posterolateral footprint (PL-PL reconstruction) with a reconstruction technique with tibial posterolateral and femoral anteromedial tunnel placement (PL-AM reconstruction). In 9 fresh-frozen human cadaveric knees, the knee kinematics under simulated Lachman (134 N anterior tibial load) and a simulated pivot shift test (10 N/m valgus and 4 N/m internal tibial torque) were determined at 0°, 30°, 60°, and 90° of flexion. Kinematics were recorded for intact, ACL-deficient, and single-bundle ACL reconstructed knees using three different reconstruction strategies in randomized order: (1) PL-AM, (2) AM-AM and (3) PL-PL reconstructions. Under simulated Lachman test, single-bundle PL-AM reconstruction and PL-PL reconstructions both showed significantly increased anterior tibial translation (ATT) at 60° and 90° when compared to the intact knee. At all flexion angles, AM-AM reconstruction did not show any statistical significant differences in ATT compared to the intact knee. Under simulated pivot shift, PL-AM reconstruction resulted in significantly higher ATT at 0°, 30°, and 60° knee flexion and AM-AM reconstructions showed significantly higher ATT at 30° compared to the intact knee. PL-PL reconstructions did not show any significant differences to the intact knee. AM-AM reconstructions restore the intact knee kinematics more closely when compared to a PL-AM technique resembling a transtibial approach. PL-PL reconstructions showed increased ATT at higher flexion angles, however, secured the rotational stability at all flexion angles. Due to the independent tibial and femoral tunnel location, a medial portal technique may be superior to a transtibial approach.     

The importance of quantitative measurement methods for uveitis: laser flare photometry endorsed in Europe while neglected in Japan where the technology measuring quantitatively intraocular inflammation was developed

Laser flare photometry (LFP) is an objective and quantitative method to measure intraocular inflammation. The LFP technology was developed in Japan and has been commercially available since 1990. The aim of this work was to review the application of LFP in uveitis practice in Europe compared to Japan where the technology was born. We reviewed PubMed articles published on LFP and uveitis. Although LFP has been largely integrated in routine uveitis practice in Europe, it has been comparatively neglected in Japan and still has not received FDA approval in the USA. As LFP is the only method that provides a precise measure of intraocular inflammation, it should be used as a gold standard in uveitis centres worldwide.     

Endotoxin-induced uveitis in the rat

Intraocular inflammation was induced in the rat by footpad injection of salmonella endotoxin in order to study the influence of chemical inflammation mediators in this uveitis model. Ocular inflammation was assessed 1, 6, 18, 24 and 72 h after endotoxin administration as well as in control rats, by measuring aqueous protein concentration, aqueous inflammatory cell content, and pupillary diameter. Thromboxane B2 (TXB2), prostaglandin E2 (PGE2), prostaglandin F2 alpha (PGF2-alpha), leukotriene B4 (LTB4), and substance P were simultaneously measured in the aqueous humor by radioimmunoassay. Inflammation parameters peaked at 18 h. TXB2 was already significantly elevated at 1 h. PGE2 peak values of 2.7 ng/ml were reached at 18 h. PGF2-alpha was never significantly raised over control values. LTB4 peaked at 18 h, together with a polymorphonuclear peak. Substance P was significantly elevated after 6 h. It is concluded that maximal uveitis in this model occurs at 18 h. TXB2 is an early mediator, and PGE2 is probably implicated in blood-ocular barrier disruption for which levels as high as 2.7 ng/ml in aqueous seem necessary. PGF2-alpha does not play a major role in this model, while LTB4 seems to be the main chemotactic factor for polymorphonuclears (PMNs) in the anterior chamber and substance P is clearly related to pupil miosis.     

Surgeon experience with dynamic intraligamentary stabilization does not influence risk of failure

Purpose

Studies on dynamic intraligamentary stabilization (DIS) of acute anterior cruciate ligament (ACL) ruptures reported failure rates similar to those of conventional ACL reconstruction. This study aimed to determine whether surgeon experience with DIS is associated with revision rates or patient-reported outcomes. The hypothesis was that more experienced surgeons achieved better outcomes following DIS due to substantial learning curve.

Methods

The authors prospectively enrolled 110 consecutive patients that underwent DIS and evaluated them at a minimum of 2 years. The effects of independent variables (surgeon experience, gender, age, adjuvant procedures, tear location, preinjury Tegner score, time from injury to surgery, and follow-up) on four principal outcomes (revision ACL surgery, any re-operation, IKDC and Lysholm score) were analyzed using univariable and multivariable regressions.

Results

From the 110 patients enrolled, 14 patients (13%) were lost to follow-up. Of the remaining 96 patients, 11 underwent revision ACL surgery, leaving 85 patients for clinical assessment at a mean of 2.2?±?0.4 years (range 2.0–3.8). Arthroscopic reoperations were performed in 26 (27%) patients, including 11 (11%) revision ACL surgeries. Multivariable regressions revealed: (1) no associations between the reoperation rate and the independent variables, (2) better IKDC scores for ‘designer surgeons’ (b?=?10.7; CI 4.9–16.5; p?<?0.001), higher preinjury Tegner scores (b?=?2.5, CI 0.8–4.2; p?=?0.005), and younger patients (b?=?0.3, CI 0.0–0.6; p?=?0.039), and (3) better Lysholm scores for ‘designer surgeons’ (b?=?7.8, CI 2.8–12.8; p?=?0.005) and preinjury Tegner score (b?=?1.9, CI 0.5–3.4; p?=?0.010).

Conclusion

Surgeon experience with DIS was not associated with rates of revision ACL surgery or general re-operations. Future, larger-scaled studies are needed to confirm these findings. Patients operated by ‘designer surgeons’ had slightly better IKDC and Lysholm scores, which could be due to better patient selection and/or positively biased attitudes of both surgeons and patients.

Level of evidence

Level II, prospective comparative study.

     

Changes in gait pattern and early functional results after ACL repair are comparable to those of ACL reconstruction

Purpose

Dynamic intraligamentary stabilization (DIS) has been introduced as a new technique to repair the torn anterior cruciate ligament (ACL) and to restore knee joint kinematics after an acute ACL tear. Aim of the present study was to compare the early post-operative activity, restoration of gait pattern and functional results after DIS in comparison with primary ACL reconstruction (ACLR) for acute ACL tears. It was hypothesized that functional results, post-operative activity and changes in gait pattern after DIS are comparable to those after ACLR.

Methods

Sixty patients with acute ACL tears were included in this study and underwent either DIS or ACLR with an anatomic semitendinosus autograft in a randomized manner. Patients were equipped with an accelerometric step counter for the first 6 weeks after surgery in order to monitor their early post-operative activity. 3D gait analysis was performed at 6 weeks and 6 months after surgery. Temporal-spatial, kinematic and kinetic parameters were extracted and averaged for each subject. Functional results were recorded at 6 weeks, 6 months and 12 months after surgery using the Tegner activity scale, International Knee Documentation Committee score and Lysholm score.

Results

Patients who underwent DIS showed an increased early post-operative activity with significant differences at week 2 and 3 (p = 0.0241 and 0.0220). No significant differences between groups were found for knee kinematic and kinetic parameters or the functional scores at any time of the follow-up. Furthermore, the difference in anterior tibial translation was not significantly different between the two groups (n.s.).

Conclusion

Early functional results and changes in gait pattern after DIS are comparable to those of primary ACLR. Therefore, ACL repair may be an alternative to ACLR in this cohort of patients.

Level of evidence

I.