Is Total Knee Arthroplasty Surgical Performance Enhanced Using Augmented Reality? A Single-Center Study on 76 Consecutive Patients.

BACKGROUND: Augmented reality (AR) is a powerful multipurpose tool. With a dedicated visor, AR allows the visualization of a series of information and/or images superimposed on the user's field of vision. For this reason, it was recently introduced as a surgical assistant tool. This single-center study aimed to evaluate the intraoperative outcomes of total knee arthroplasties performed with AR assistance in terms of time required and the difference between preplanned and achieved implant positioning (in terms of tibial cut varus and slope angles). METHODS: A total of 76 consecutive patients was selected. Preplanning was performed according to the AR protocol, and the target varus and slope angles were defined to instruct the device, which subsequently guided the tibial cuts intraoperatively. Surgeries were performed starting from the tibial cut, and the time required to perform the calibration, registration, and fixation of the resection block was recorded. The varus and slope angles achieved were recorded to compare with the preplanned ones to determine the means and SDs of the differences. RESULTS: The mean usage time of the AR tool was 5 ± 1 minutes. Results showed a mean difference of 0.59 ± 0.55° for varus angles and 0.70 ± 0.75° for the slope. For varus angles, the differences were <1° for 96% of the cases. Concerning the slope, 89% of the cases were <1°. CONCLUSION: The results showed excellent accuracy of the surgical cuts and a limited increase in surgery duration. Therefore, these outcomes highlighted the potential of this new technology as a valid option for surgical assistance.

Bankart Repair With Subscapularis Augmentation in Athletes With Shoulder Hyperlaxity.

PURPOSE: The purpose of this study was to demonstrate that arthroscopic Bankart repair with associated arthroscopic subscapularis augmentation (ASA) could be a valid surgical option in the treatment of anterior shoulder instability, in collision and contact sports athletes, affected by shoulder hyperlaxity. METHODS: In total, 591 arthroscopic Bankart repairs plus ASA were performed in 6 shoulder centers from 2009 to 2017. Inclusion criteria were the following: collision and contact sports activities, recurrent anterior instability associated with hyperlaxity and glenoid bone loss (GBL) < 15%. Exclusion criteria were GBL > 15%, voluntary instability, multidirectional instability, pre-existing osteoarthritis and throwing athletes. The minimum follow-up was 24 months. Hyperlaxity was clinically evaluated according to Neer and Coudane-Walch tests. Before surgery, all patients underwent magnetic resonance imaging and computed tomography scanning. Pico area method was used to assess the percentage of GBL. Patients were operated on by 6 surgeons, and their functional outcomes were evaluated by 2 independent observers. The Western Ontario Shoulder Instability Index (WOSI), Rowe, American Shoulder and Elbow Surgeons (ASES) scores were used to assess results. RESULTS: Overall, 397 patients with evidence of shoulder hyperlaxity (positive sulcus sign in ER1 position and Coudane-Walch test > 85°) met all inclusion criteria. The mean WOSI score was 321; the mean Rowe score rose from 68.5 to 92.5 (P = .037), and the ASES score rose from 71.5 to 97.4 (P = .041). Seven patients (1.6%) had atraumatic redislocation, and 9 patients (2.2%) had post-traumatic redislocation. At final follow-up the mean functional deficit of external rotation was 15° with the arm in adduction (ER1 position) and 10° in abduction (ER2 position). CONCLUSIONS: The Bankart repair plus ASA has been demonstrated to be safe and effective for restoring joint stability in patients practicing collision and contact sports or affected by chronic anterior shoulder instability associated with GBL (<15%) and hyperlaxity, without compromising external rotation. LEVEL OF EVIDENCE: Level IV, case series.

A simple technique to perform total knee replacement without violating the femoral canal: early clinical results on a cohort of 303 patients.

BACKGROUND: It is becoming increasingly common to find patients candidate for total knee replacement with inaccessible femoral canal due to long femoral hip stems, osteo-synthetic hardware or diaphyseal mal-unions. To treat those patients avoiding complex and expensive procedures, we developed an innovative surgical technique based on a novel device called extra-medullary alignment system. We initially employed this technique in 18 cases with inaccessible femoral canal. Early results were so encouraging that we adopted this technique also for our standard cases. MATERIALS AND METHODS: We report here our findings with a first series of 303 consecutive patients performed employing this technique. All patients received a cemented cruciate-retaining mobile-bearing total knee. Patients were followed for a minimum of 2 years and evaluated employing the Knee Society Score and the Oxford questionnaire. We also recorded the surgical time and any complication occurred intra-operatively and postoperatively. Patients' X-rays were as well evaluated. RESULTS: No patient was lost to follow-up. Patients group average Knee Society and Oxford scores improved, respectively, from 45 and 16 pre-op to 92 and 45 at 2-year follow-up. Those results were compared and found aligned to those reported by similar historic control groups. Prosthetic implant alignment and surgical time demonstrated to be similar the one obtained using endo-medullary-referenced instruments. In this series, we did not observe any meaningful complication. CONCLUSIONS: The extra-medullary alignment system seems to be a simple and reliable technique enabling to perform total knee replacement in a truly minimal invasive manner avoiding femoral canal violation. LEVEL OF EVIDENCE: IV.

Asymmetric polyethylene inserts promote favorable kinematics and better clinical outcome compared to symmetric inserts in a mobile bearing total knee arthroplasty.

PURPOSE: This study aims at comparing the effects of symmetric and asymmetric designs for the polyethylene insert currently available and also for mobile bearing total knee arthroplasty (TKA). The investigation was performed both clinically and biomechanically through finite element analysis. METHODS: 303 patients, with a mobile bearing TKA, were analyzed retrospectively. All patients received the same femoral and tibial components; for the insert, 151 patients received a symmetric design (SD) and 152 an asymmetric design (AD). Additionally, a 3D finite element model of a lower leg was developed, resurfaced with the same TKAs and analysed during gait and squat activities. TKA kinematics, and bone-stresses were investigated for the two insert solutions. RESULTS: After surgery, patients' average flexion improved from 105°, with 5° of preoperative extension deficit, to 120° (AD-group) and 115° (SD-group) at the latest follow-up. There was no postoperative extension deficit. No pain affected the AD-group, while an antero-lateral pain was reported in some patients of the SD-group. Patients of the AD-group presented a better ability to perform certain physical routines. Biomechanically, the SD induced higher tibial-bone stresses than the AD. Both designs replicated similar kinematics, comparable to literature. However, SD rotates more on the tray, reducing the motion between femoral and polyethylene components, while AD permits greater insert rotation. CONCLUSION: The biomechanical analysis justifies the clinical findings. TKA kinematics is similar for the two designs, although the asymmetric solution shows less bone stress, thus resulting as more suitable to be cemented, avoiding lift-off issues, inducing less pain. Clinically, and biomechanically, an asymmetric mobile bearing insert could be a valid alternative to symmetric mobile bearing insert. LEVEL OF EVIDENCE: Case-control study retrospective comparative study, III.

Biomechanical analysis of different levels of constraint in TKA during daily activities.

BACKGROUND: Numerous total knee prosthetic implants are currently available on the orthopedic market, and this variety covers a set of different levels of constraint: among the various models available, a significant role is covered by mobile bearing cruciate-retaining design with an ultra-congruent insert, mobile bearing cruciate-retaining design, fixed-bearing posterior stabilized prosthesis and fixed-bearing constrained condylar knee. A biomechanical comparative study among them could therefore be helpful for the clinical decision-making process. This study aimed to compare the effect of these different levels of constraint in the knee biomechanics of a patient, in three different configurations representing the typical boundary conditions experienced by the knee joint during daily activities. METHOD: The investigation was performed via finite element analysis with a knee model based on an already published and validated one. Four different types of prosthesis designs were analyzed: two mobile-bearing models and two fixed-bearing models, each one having a different level of constraint. The different designs were incorporated in to the 3D finite element model of the lower leg and analyzed in three different configurations reproducing the landing and the taking-off phases occurring during the gait cycle and chair-rising. Implant kinetics (in terms of polyethylene contact areas and contact pressure), polyethylene and tibial bone stresses were calculated under three different loading conditions for each design. RESULTS: The tibial stress distribution in the different regions of interest of the tibia remains relatively homogeneous regardless of the type of design used. The main relevant difference was observed between the mobile and fixed-bearing models, as the contact areas were significantly different between these models in the different loading conditions. As a consequence, significant changes in the stress distribution were observed at the interface between the prosthetic components, but no significant changes were noted on the tibial bone. Moreover, the different models exhibited a symmetrical medial and lateral distribution of the contact areas, which was not always common among all the currently available prostheses (i.e. medial pivot designs). CONCLUSION: The changes of the prosthetic implant did not induce a big variation of the stress distribution in the different regions of the tibial bone, while they significantly changed the distribution of stress at the interface between the prosthetic components.

The effect of different insert design congruencies on the kinematics of a mobile bearing TKA: A cadaveric study.

Introduction: Total knee arthroplasty has proved to be a safe, effective and reproducible surgical treatment for patients with serious/advanced degenerative joint disease of the knee, but the optimal results after these implants can be achieved only if the joint kinematics and kinetics are carefully respected and not significantly altered after the replacement. In order to enhance the capability of matching the healthy configuration, therefore, different prosthesis models in terms of constraints and designs are available for the surgeons to choose among. As an example of this variety, mobile bearing models allow the surgeon to choose among different insert designs in terms of geometry and relative biomechanical approaches, with the relative performances depending on which one is adopted.This article aims to analyse the effect of different levels of congruency of mobile bearing inserts through an experimental activity performed on an ultra-congruent insert design, also referred as deep-dished. Methods: The experimental activity followed the same protocol used in a previous study focused on the effect of symmetricity/asymmetricity (in order to allow a comparison among the results obtained), i.e. it analysed passive squat on 5 cadaveric knee specimens; internal-external rotations of femur and tibial insert respect to the tibia tray were thus measured via a motion capture system in order to compare the insert-femur relative rotation among the different congruency configurations. Results: The overall knee kinematic (in terms of flexion-extension and internal-external rotation ranges of motion) with an ultra-congruent insert did not differ from the ones found for the other inserts; the insert-femur rotation values, instead, returned to be between the ones obtained with the other two inserts. Conclusion: In terms of adaptability to tibio-femoral rotation, therefore, this insert represents a valid option for the surgeon seeking for an intermediate solution among the opposed approaches of the other two.

The use of mobile bearing TKA in valgus deformities - A clinical study.

BACKGROUND: The number of patients presenting valgus deformities undergoing total knee arthroplasty (TKA) represents approximately 10% of the total number of TKAs performed: the presence of valgus deformity requires the implant to have proper alignment, stability and balance to achieve successful clinical outcomes, especially for knees with high coronal deformities, but these have proven to be difficult goals to achieve and therefore the use of constrained prostheses is often recommended for these cases. However, even though the use of unconstrained mobile bearing for severe knee deformities is rare, it has been shown to give successful outcomes and therefore the aim of this study is to evaluate whether this surgical technique can achieve satisfactory clinical results and correct alignment, as well as good patient satisfaction. METHODS: This study presents the results of 69 TKA performed with cemented mobile bearing implants by a single surgeon on knee affected by valgus deformities. Asymmetric inserts were adopted for all the implants and an alignment surgical tool, dedicated for valgus patients, was used during the operation. Angles of valgus, WOMAC surveys and Numeric Rating Scale for pain were recorded to evaluate the results of the operations. RESULTS: A total of 67 pre-op WOMAC questionnaire surveys were collected, with the mean result of this evaluation being 15.9 points. The Numeric Rating Scale for pain had an average of 2.2 for 68 tests. The deformities were corrected from a mean total preoperative valgus angle of 12.5° to a postoperative valgus deformity average of 0.6°. During follow-up, only one patient had serious complications due to the rupture of the extensor apparatus following a domestic accident involving falling. Further 10 patients have mild complications related to injuries such as pain of varying intensity, burning, or swelling of the knee. The level of satisfaction from 0 to 10 (0 not at all satisfied and 10 perfectly satisfied) had an average score of 7.7. CONCLUSIONS: The surgical approach presented, involving a less constrained model if compared to the ones usually chosen, allowed to achieve correct alignment and high patient satisfaction using mobile bearing implants on valgus knee deformities; further patient follow-up will be performed to evaluate long-term outcomes, but the results achieved already represent a significative finding.

Experimental and clinical analysis of the use of asymmetric vs symmetric polyethylene inserts in a mobile bearing total knee arthroplasty.

PURPOSE: This study compared the effects of symmetric and asymmetric designs for mobile bearing polyethylene insert for total knee arthroplasty (TKA), both clinically and biomechanically through experimental cadaver tests. METHODS: 303 patients implanted with a mobile bearing TKA were retrospectively analyzed up to 2-year follow-up with relative scores. The same femoral and tibial components were used for all the patients; 151 patients received a Symmetric Design (SD) insert and 152 an Asymmetric Design (AD). A biomechanical experimental test was performed to improve the comprehension of the clinical results, analyzing passive squat on 5 cadaveric knee specimens: internal-external rotations of femur and tibial insert respect to the tibia tray were analyzed in native and implanted configurations (with both symmetrical and asymmetrical inserts for each specimen). RESULTS: After surgery, patients' average flexion improved from 105° (with preoperative extension deficit of 5°), to 115° (SD-group) and 120° (AD-group) at the 2-year follow-up. There was no postoperative extension deficit. AD-group presented better ability to perform certain routines and wasn't affected by any pain, while antero-lateral pain was reported in some SD-group patients. The experimental tests returned no statistically relevant difference in tibio-femoral flexion-extension and internal-external rotations among all the three configurations tested; a statistically significant difference is found for insert-tray internal-external rotations between SD and AD configurations; in details, the AD insert showed insert-tray angles comparable to the ones found for femoral component-tibial tray, while the SD insert returned lower angular values. CONCLUSION: Clinically and biomechanically, an asymmetric mobile bearing insert could represent a valid alternative to symmetric mobile bearing insert. LEVEL OF EVIDENCE: III, Case-control study Retrospective comparative study.

A novel surgical technique to perform total knee arthroplasty in patients with inaccessible femoral medullary canal.

Not seldom Surgeons have to deal with total knee cases where the femoral intramedullary canal is not accessible due to hardware still in place, long hip stems or diaphyseal mal-unions, so intra-medullary referenced instrumentations cannot be employed. We developed a novel instrument called EMAS (Extra Medullary Alignment System) able to help addressing those cases in a simple and reproducible way avoiding the use of more complex and expensive technologies. We present the results achieved using EMAS on 18 of those difficult cases with a maximum follow-up of 7 years as well as our experience using EMAS in our standard practice.

Standard sonography and arthrosonography in the study of rotator cuff tears.

PURPOSE: The aim of this study was to evaluate the sensitivity of ultrasonography, integrating standard ultrasound and arthrosonography after injecting a saline solution into the glenohumeral cavity in cases of suspected rotator cuff tears. MATERIALS AND METHODS: We prospectively examined 40 patients awaiting shoulder arthroscopy for suspected or diagnosed tears of the rotator cuff. A radiologist, unaware of the pre-operative diagnosis, performed an ultrasound scan on all the patients before and after the injection of saline solution into the glenohumeral cavity. The parameters considered were presence or absence of a rotator cuff injury; type of injury according to Snyder and its extent along the longitudinal and transverse planes; presence or absence of effusion into the articular cavity; subacromial/subdeltoid bursal distension. All the patients underwent arthroscopy either the same day or the day after the ultrasound examination. RESULTS: Standard sonography showed 26 complete rotator cuff tears (type C according to Snyder), 2 partial tears (type B according to Snyder) and 12 intact rotator cuffs. Arthrosonography detected 31 complete rotator cuff tears (type C according to Snyder), 1 partial tear (type B according to Snyder) and 8 intact rotator cuffs.Arthroscopy identified 32 complete rotator cuff tears (type C according to Snyder), 1 partial tear (type B according to Snyder) and 8 intact rotator cuffs. Analysis of the results shows that, taking arthroscopy as the gold standard, the sensitivity of normal sonography is 81.2%, whereas that of arthrosonography is 96.8% (p < 0.05). CONCLUSIONS: On the basis of the data obtained in this study, standard sonography, integrated with the injection of a saline solution into the glenohumeral cavity, considerably increases the diagnostic sensitivity for rotator cuff tears. The authors suggest that arthrosonography can be used in the event of suspected rotator cuff tears, when MRI is contraindicated.

Manipulation and arthroscopy under general anesthesia and early rehabilitative treatment for frozen shoulders.

OBJECTIVE: To evaluate the efficacy of manipulation followed by arthroscopic release of the glenohumeral joint in conjunction with an immediate and intensive rehabilitation program. DESIGN: Retrospective, descriptive study. SETTING: A free-standing, university-affiliated orthopedics and rehabilitation hospital. PARTICIPANTS: Forty patients with a clinical diagnosis of adhesive capsulitis resistant to pharmacologic and physical therapy (PT). INTERVENTIONS: Patients underwent manipulation and arthroscopic release of the capsular joint and were given an intensive PT program on the first postoperative day. MAIN OUTCOME MEASURES: All patients were evaluated pre- and postoperatively at follow-up at an average of 42 months by using the Simple Shoulder Test (SST), the Constant-Murley system score, and passive (PROM) and active (AROM) range of motion. RESULTS: The SST, which showed a mean preoperative score of 2.2+/-0.7, was 10.8+/-0.7 (P<.001) after surgery. Preoperatively, the mean Constant-Murley score was 33.2%+/-1.9%; postoperatively, the mean score was 91.7%+/-2.9% (P<.001). PROM increased from 90 degrees to 165 degrees for anterior elevation, from 85 degrees to 160 degrees for abduction, from 20 degrees to 60 degrees for external rotation, and from 10 degrees to 40 degrees for internal rotation. AROM improved for anterior elevation from 82 degrees to 155 degrees; for abduction from 77 degrees to 143 degrees, and for external rotation, with the arm along the patient's side, from 5 degrees to 50 degrees. CONCLUSIONS: Results support the efficacy of manipulation follow by arthroscopic release and rehabilitative treatment for patients with resistant adhesive capsulitis of the shoulder.