Daniele Mazza

Extra-articular ACL reconstruction and pivot shift: In vivo dynamic evaluation with navigation

Background: The pivot-shift test is considered a reliable examination to evaluate the results of anterior cruciate ligament (ACL) reconstruction, as it strongly correlates with patient satisfaction, giving-way episodes, and activity level. The addition of lateral tenodesis (LT) to current techniques of intra-articular reconstruction with a hamstring graft could potentially improve knee laxity in cases of severe rotational instability. Purpose: To biomechanically investigate the effect of intra- and extra-articular ACL reconstructions on knee laxity and the pivot-shift phenomenon. Study Design: Controlled laboratory study. Methods: Twenty patients underwent anatomic single-bundle ACL reconstruction with doubled semitendinosus and gracilis tendons with the addition of extra-articular reconstruction. In patients in group A, intra-articular reconstruction was performed first and LT thereafter; in patients in group B, LT was performed first and intra-articular reconstruction thereafter. A navigator equipped with software designed for both static and dynamic evaluations was used to measure maximum anterior tibial translation (ATT) and axial tibial rotation (ATR) at 30° of flexion (static evaluation) and during the pivot-shift test (dynamic evaluation). Measurements were performed before reconstruction, after the first procedure, and after the second procedure. Results: For the static evaluation, in group A, the mean ATT significantly decreased from 14.1 ± 3.7 mm in the preoperative (ACL-deficient) condition to 6.0 ± 1.9 mm after ACL reconstruction and to 5.3 ± 1.6 mm after LT. The mean ATR at 30° of knee flexion significantly decreased from 35.7° ± 4.8° to 28.9° ± 4.1° and to 20.9° ± 4.8°, respectively. In group B, the mean ATT significantly decreased from 13.5 ± 6.5 mm in the preoperative (ACL-deficient) condition to 10.2 ± 3.2 mm after LT and to 4.0 ± 1.6 mm after ACL reconstruction. The mean ATR at 30° of knee flexion significantly decreased from 36.7° ± 4.8° to 26.2° ± 6.2° and to 23.5° ± 4.9°, respectively. For the dynamic evaluation (pivot-shift test), in group A, the mean ATT significantly decreased from 15.0 ± 6.8 mm in the preoperative (ACL-deficient) condition to 9.4 ± 6.4 mm after ACL reconstruction and to 8.5 ± 5.4 mm after LT. The mean ATR significantly decreased from 16.9° ± 4.7° to 11.6° ± 4.1° and to 6.1° ± 2.2°, respectively. In group B, the mean ATT significantly decreased from 12.5 ± 3.3 mm in the preoperative (ACL-deficient) condition to 9.1 ± 5.9 mm after LT and to 8.1 ± 5.4 mm after ACL reconstruction. The mean ATR significantly decreased from 16.0° ± 4.5° to 9.2° ± 4.3° and to 7.5° ± 4.0°, respectively. Conclusion/Clinical Relevance: Extra-articular reconstruction had little effect in reducing the anterior displacement of the tibia at 30° of flexion, but it was more effective than intra-articular reconstruction in reducing ATR. Anatomic ACL reconstruction and LT were synergic in controlling the pivot-shift phenomenon.

Are MRI-based, patient matched cutting jigs as accurate as the tibial guides?

PurposeThe aim of this study is to evaluate the accuracy of VISIONAIRE (Smith & Nephew Inc., Memphis, TN, USA) Patient Matched cutting tibial jigs in comparison with extramedullary (EM) tibial instrumentation by analysing data as detected by intra-operative use of VectorVision knee navigation software from BrainLAB (Redwood City, CA, USA).MethodsTwelve patients were selected for unilateral total knee replacement (TKR). They underwent a full-length weight-bearing anteroposterior (AP) radiograph and magnetic resonance imaging (MRI). During surgery, once the EM guides were placed and fixed on the tibia, the orientation in the coronal and sagittal planes was checked by the navigator and then compared with the data obtained by measuring the orientation of VISIONAIRE Patient Matched cutting tibial jigs. An unsatisfactory result was considered an error ≥2° in both coronal and sagittal planes for the tibial component as a possible error of 4° could result.ResultsIn the coronal plane the mean deviation of the EM tibial guides from the ideal alignment (0°) was 0.7 ± 0.39° and of the VISIONAIRE was 129 ± 1.55° (P = 0.22). In the sagittal plane the mean deviation of the EM tibial guides from 3° of posterior slope was −1.62 ± 1.78° and of the VISIONAIRE was +1.16 ± 4.29° (P < 0.05). Negative values indicate a more posterior slope from the ideal and positive values an anterior slope.ConclusionsThis preliminary study documented only a fair accuracy of the method with a consistent risk of error of more of 3° especially in the sagittal plane. We could speculate that the problem in the sagittal plane was due to the fact that the pre-operative protocol does not include a lateral X-ray projection of the knee and only includes an AP standing X-ray of the straight leg and MRI.

Patient-specific instruments in total knee arthroplasty

PurposeIn recent years, patient-specific instruments (PSI) has been introduced with the aim of reducing the overall costs of the implants, minimising the size and number of instruments required, and also reducing surgery time. The purpose of this study was to perform a review of the current literature, as well as to report about our personal experience, to assess reliability of patient specific instrument system in total knee arthroplasty (TKA).MethodsA literature review was conducted of PSI system reviewing articles related to coronal alignment, clinical knee and function scores, cost, patient satisfaction and complications.ResultsStudies have reported incidences of coronal alignment ≥3° from neutral in TKAs performed with patient-specific cutting guides ranging from 6 % to 31 %.ConclusionsPSI seem not to be able to result in the same degree of accuracy as the CAS system, while comparing well with standard manual technique with respect to component positioning and overall lower axis, in particular in the sagittal plane. In cases in which custom-made cutting jigs were used, we recommend performing an accurate control of the alignment before and after any cuts and in any further step of the procedure, in order to avoid possible outliers.

Computer-assisted surgery: A teacher of TKAs

INTRODUCTION The hypothesis of this study is that computer-aided navigation experience could improve the ability to better place components in the coronal plane and to improve visual/spatial awareness based on the ability of navigation to provide instant feedback. The purpose of this study is to demonstrate the educational role of the navigation system to obtain a better alignment of the prosthetic components with standard instrumentation after a computer-aided navigation experience. MATERIALS AND METHODS One hundred fifty patients were operated by the same surgeon, with more than 5 years experience with TKA. They were equally divided in three groups: group A (operated with non-navigated technique by surgeon without computer-assisted experience); group B (operated with computer-assisted surgery by the same surgeon); group C (operated with non-navigated technique by the same surgeon after the computer-navigated experience). We evaluated by full-length weight-bearing radiographs the overall alignment of the lower limb in the coronal plane. The optimum placement of the components was considered when the angle was within the limits of ±3° varus/valgus on the coronal x-rays. Comparison between groups was done using one-way ANOVA followed by post hoc Bonferroni test and Pearson chi-square statistics for proportions of optimum placement (P<0.05). RESULTS In the group A 34 patients (68%) had the optimum placement on the coronal x-rays; in the group B they were 46 (92%) and in the group 41 (82%). The difference is statistically significant in comparing group A and Group B (<0.001), group A and group C (P=0.04), but not for group B and C (P=0.2). CONCLUSION We believe that the navigation system has an educational role to improve the ability of surgeon of positioning prosthetic components precisely in the coronal plane.

Surgical Treatment of Segond Fractures in Acute Anterior Cruciate Ligament Reconstruction

Background: The Segond fracture is an avulsion-type fracture located on the anterolateral aspect of the tibia associated with a ligament recently termed the anterolateral ligament. This injury has been described as pathognomonic for an anterior cruciate ligament (ACL) tear and is associated with a higher grade pivot shift. Purpose: To present and report 2-year clinical outcomes of a surgical technique for acute ACL reconstruction with fixation of a concomitant Segond fracture. Study Design: Case series; Level of evidence, 4. Methods: A retrospective chart review was performed of patients who underwent acute reconstruction for a complete ACL tear with concomitant Segond fracture fixation between January 2010 and December 2014; surgery was performed by a single surgeon. Patients underwent direct Segond fracture repair by either suture alone, suture anchor, or cannulated screw fixation based on the size of the lesion, followed by a 2-incision hamstring autograft intra-articular reconstruction. Pre- and postoperative KT-1000 arthrometer assessment, Lachman test, and pivot-shift test were performed, and patients were administered validated subjective outcome surveys. Results: Twelve patients met inclusion criteria for this review. The measured pre- and postoperative objective and subjective scores were significantly improved in all patients. Side-to-side anterior laxity was significantly improved in all patients based on Lachman and KT-1000 arthrometer testing. A significant pivot shift demonstrated preoperatively (3+, n = 11 [92%]; 2+, n = 1 [8%]) was corrected after fixation, except in 1 patient (8%), who maintained a 1+ pivot shift. Lysholm, Tegner, and International Knee Documentation Committee subjective and objective scores were significantly improved. At a minimum 2-year follow-up, no patients reported rerupture, and only 1 patient (8%) underwent a subsequent procedure (a meniscectomy). No major or minor complications were reported, and all patients returned to their previous activity levels at a mean of 6 months postoperatively. Conclusion: Direct repair of the Segond fracture and plication of the anterolateral capsule in patients with an ACL rupture and a high-grade pivot shift demonstrate good clinical outcomes, restoration of rotational stability, and maintenance of knee range of motion at 2 years postoperatively, with no major complications.

I.S.Mu.L.T. First-time patellar dislocation guidelines

Primary traumatic patellar dislocation is common, particularly in young active individuals. A consensus on its management is still lacking. The present work provides easily accessible guidelines to be considered as recommendations for a good clinical practice developed through a process of systematic review of the literature and expert opinion, to improve the quality of care and rationalize the use of resources. LEVEL OF EVIDENCE Ia.

The Fascia Lata Anterolateral Tenodesis Technique

A technique for anatomic reconstruction of the anterolateral complex addressing anterolateral rotatory instability both in primary anterior cruciate ligament reconstruction and in revision cases is presented. The extra-articular reconstruction is performed with a pedicle strip of iliotibial tract, fixed on the anatomic origin and insertion points of the anterolateral ligament of the knee in a double-bundle V-shaped fashion.

High-speed gateable image pipeline

We present the results obtained with a prototype of a high speed gateable Vacuum Image Pipeline (VIP) for selection of non-repetitive images from a continuous stream. It allows snapshots with a very short exposure time (of the order of 10 nanoseconds) to be accepted (or rejected) after a decision time of a few microseconds. The VIP is a vacuum tube equipped with a photocathode, a system of metallic grids and a phosphor screen. Photoelectrons produced by the images focused on the photocathode are guided by a uniform magnetic field parallel to the tube axis. By acting on the grid potentials, the drift time of the photoelectrons inside the tube can be adjusted between 0.3 and 2 microseconds. An image among many others can then be selected by an external trigger with a time resolution between 4 and 30 ns depending on the delay time. The selected photoelectrons are finally accelerated by a high potential (+15 kV) onto the phosphor screen where they reproduce the triggered image. A spatial resolution of 33 lp/mm at a magnetic field of 0.1 T has been measured. The VIP is a useful tool for high energy physics and astrophysics experiments as well as in high speed photography.

Chest pain caused by multiple exostoses of the ribs: A case report and a review of literature

The aim of this paper is to report an exceptional case of multiple internal exostoses of the ribs in a young patient affected by multiple hereditary exostoses (MHE) coming to our observation for chest pain as the only symptom of an intra-thoracic localization. A 16 years old patient with familiar history of MHE came to our observation complaining a left-sided chest pain. This pain had increased in the last months with no correlation to a traumatic event. The computed tomography (CT) scan revealed the presence of three exostoses located on the left third, fourth and sixth ribs, all protruding into the thoracic cavity, directly in contact with visceral pleura. Moreover, the apex of the one located on the sixth rib revealed to be only 12 mm away from pericardium. Patient underwent video-assisted thoracoscopy with an additional 4-cm mini toracotomy approach. At the last 1-year follow-up, patient was very satisfied and no signs of recurrence or major complication had occured. In conclusion, chest pain could be the only symptom of an intra-thoracic exostoses localization, possibly leading to serious complications. Thoracic localization in MHE must be suspected when patients complain chest pain. A chest CT scan is indicated to confirm exostoses and to clarify relationship with surrounding structures. Video-assisted thoracoscopic surgery can be considered a valuable option for exostoses removal, alone or in addiction to a mini-thoracotomy approach, in order to reduce thoracotomy morbidity.

Endoscopic Excision of Symptomatic Os Trigonum in Professional Dancers

Abstract The present study reports the clinical results of excision of a symptomatic os trigonum using an endoscopic procedure in professional ballet dancers. The hypothesis was that posterior endoscopic excision of the os trigonum would be safe and effective in treating posterior ankle impingement syndrome related to the os trigonum. Twelve professional dancers underwent excision of a symptomatic os trigonum for PAIS using a posterior endoscopic technique after failure of conservative treatment. The patients were evaluated pre‐ and postoperatively according to the American Orthopaedic Foot and Ankle Society hindfoot scale score, the Tegner activity scale score, and the visual analog scale score. The surgical time, timing of a return to sports, patient satisfaction, and any complications related to the procedure were recorded. The average postoperative follow‐up duration was 38.9 ± 20.6 (range 12 to 72) months. The mean Tegner activity scale score increased from 4.3 ± 0.8 (range 3 to 5) preoperatively to 9 ± 0.2 postoperatively (p < .05). The mean American Orthopaedic Foot and Ankle Society scale score increased from 67.8 ± 6.0 (range 58 to 76) preoperatively to 96 ± 5.1 (range 87 to 100) postoperatively, with 7 of 12 patients (58.3%) reporting the maximum score of 100 points (p < .05). The return to sports was 8.7 ± 0.7 (range 8 to 10) weeks. No major complications were recorded. The results of the present study demonstrate that the endoscopic excision of symptomatic os trigonum using a 2‐portal technique after failure of conservative treatment is characterized by excellent results with low morbidity. &NA; Level of Clinical Evidence: 4