Development and Preclinical Trials of a Novel Steerable Cannula for 360° Arthroscopic Capsular Release in Minimally Invasive Surgery

Arthroscopic device with bendable tip for the controlled extrusion of hydrogels on cartilage defects

Advanced tools for the in situ treatment of articular cartilage lesions are attracting a growing interest in both surgery and bioengineering communities. The interest is particularly high concerning the delivery of cell-laden hydrogels. The tools currently available in the state-of-the-art hardly find an effective compromise between treatment accuracy and invasiveness. This paper presents a novel arthroscopic device provided with a bendable tip for the controlled extrusion of cell-laden hydrogels. The device consists of a handheld extruder and a supply unit that allows the extrusion of hydrogels. The extruder is equipped with a disposable, bendable nitinol tip (diameter: 4 mm, length: 92 mm, maximum bending angle: 90°) that guarantees access to hard-to-reach areas of the joint, which are difficult to get to, with conventional arthroscopic instruments. The tip accommodates a biocompatible polymer tube that is directly connected to the cartridge containing the hydrogel, whose plunger is actuated by a volumetric or pneumatic supply unit (both tested, in this study). Three different chondrocyte-laden hydrogels (RGD-modified Vitrogel®, methacrylated gellan gum, and an alginate-gelatine blend) were considered. First, the performance of the device in terms of resolution in hydrogel delivery was assessed, finding values in the range between 4 and 102 µL, with better performance found for the pneumatic supply unit and no significant differences between straight tip and bent tip conditions. Finite element simulations suggested that the shear stresses and pressure levels generated during the extrusion process were compatible with a safe deposition of the hydrogels. Biological analyses confirmed a high chondrocyte viability over a 7-day period after the extrusion of the three cell-laden hydrogel types, with no differences between the two supply units. The arthroscopic device was finally tested ex vivo by nine orthopedic surgeons on human cadaver knees. The device allowed surgeons to easily deliver hydrogels even in hard-to-reach cartilage areas. The outcomes of a questionnaire completed by the surgeons demonstrated a high usability of the device, with an overall preference for the pneumatic supply unit. Our findings provide evidence supporting the future arthroscopic device translation in pre-clinical and clinical scenarios, dealing with osteoarticular treatments.

Effect of Remote Control Augmented Reality Multimedia Technology for Postoperative Rehabilitation of Knee Joint Injury

This study was aimed at exploring the application value of augmented reality (AR) in postoperative rehabilitation training for patients with knee joint injury. 40 patients who underwent knee joint injury surgery were selected as the research objects, and the patients were randomly divided into two groups: an experimental group (20 cases) and a control group (20 cases). Patients in the experimental group were treated with AR-based rehabilitation methods, while those in the control group were treated with traditional rehabilitation methods. Afterwards, the two groups of patients were compared with various indicators such as pain value, swelling, structural and functional recovery, time to complete weight bearing, time to return to work, and X-ray examination results. The main evaluation tools used were Hospital for Special Surgery (HSS) score and Visual Analogue Scale (VAS) score. The results showed that after six weeks, the HSS score of the control group was 82.88 ± 3.07, and the HSS score of the experimental group was 85.46 ± 3.21. The difference between the two groups was statistically significant (P < 0.05). After three months, the HSS score of the control group was 89.96 ± 3.76, and that of the experimental group was 93.21 ± 4.33. The difference between the two groups was statistically significant (P < 0.05). There was a significant difference in pain scores between the two groups at 7 days (3.81 ± 0.48 vs. 5.06 ± 0.66) and 14 days (2.03 ± 0.45 vs. 3.61 ± 0.63) after surgery, with statistical significances (P < 0.05). There were statistically significant differences between the two groups in terms of time to complete weight bearing (7 ± 0.87 weeks vs. 8.82 ± 0.88 weeks) and time to return to work (8.69 ± 0.94 vs. 9.93 ± 0.88 weeks) (P < 0.05). One month after surgery, the X-ray examination results of both groups showed recovery. The AR-based rehabilitation training system showed a good application effect and prospect in the postoperative structural and functional recovery of patients with knee joint injury.