Comparison of Robotic and Conventional Unicompartmental Knee Arthroplasty Outcomes in Patients with Osteoarthritis: A Retrospective Cohort Study

Robotic-arm-assisted unicompartmental knee arthroplasty (RUKA) was developed to increase the accuracy of bone alignment and implant positioning. This retrospective study explored whether RUKA has more favorable overall outcomes than conventional unicompartmental knee arthroplasty (CUKA). A total of 158 patients with medial compartment osteoarthritis were recruited, of which 85 had undergone RUKA with the Mako system and 73 had undergone CUKA. The accuracy of component positioning and bone anatomical alignment was compared using preoperative and postoperative radiograph. Clinical outcomes were evaluated using questionnaires, which the patients completed preoperatively and then postoperatively at six months, one year, and two years. In total, 52 patients from the RUKA group and 61 from the CUKA group were eligible for analysis. The preoperative health scores and Kellgren–Lawrence scores were higher in the RUKA group. RUKA exhibited higher implant positioning accuracy, thus providing a superior femoral implant angle, properly aligned implant placement, and a low rate of overhang. RUKA also achieved higher accuracy in bone anatomical alignment (tibial axis angle and anatomical axis angle) than CUKA, but surgical time was longer, and blood loss was greater. No significant differences were observed in the clinical outcomes of the two procedures.

The morphology of the proximal femur in cementless short-stem total hip arthroplasty: No negative effect on offset reconstruction, leg length difference and implant positioning

Background Correct reconstruction of hip offset (HO) and leg length are important for clinical–functional outcome and patient satisfaction in total hip arthroplasty (THA). The morphology of the proximal femur can pose a risk for increased leg length difference (LLD) in cementless straight-stem THA. We therefore wanted to evaluate, if this is also applicable in THA with a cementless meta-diaphyseal short stem. Methods In a retrospective study, 106 patients (index surgery 2014–2019) with unilateral THA and a morphologically healthy hip as a reference (Kellgren–Lawrence ≤ 1) were included. The same cementless short stem with meta-diaphyseal fixation and cementless press-fit cup was implanted. The proximal femur was rated by Dorr’s classification, and subgroups were formed afterward. Measurements were carried out on preoperative and 3 months postoperative anterior–posterior radiographs of the pelvis. Kruskal–Wallis test, Fisher’s exact test and binary logistic regression were performed to evaluate the influence of the anatomical shape on postoperative leg length difference and offset reconstruction. Results The Dorr type did not show any significance influence on LLD (p = 0.532), or postoperative difference in femoral offset (p = 0.243), acetabular offset (p = 0.106) and hip offset (p = 0.698). Stem alignment (p = 0.705) and canal fill indices (CFI I: p = 0.321; CFI II: p = 0.411; CFI III: p = 0.478) were also without significant differences. Logistic regression did not show any significant increased risk for a LLD ≥ 5 mm or ≥ 10 mm as well as HO ≥ 5 mm or ≥ 10 mm. Conclusion Reconstruction of hip offset and postoperative leg length difference is not negatively influenced by Dorr type, canal flare index, cortical index and canal-to-calcar ratio in cementless short-stem THA. Implant positioning and canal fill are also not negatively affected by the anatomical shape of the proximal femur. Level of evidence: Level IV.

New Protocol for Auditory Brainstem Implant Positioning

Background: Surgery for applying the auditory brainstem implant is an otoneurosurgery that requires careful intraoperative monitoring to optimize the placement of the electrode paddle. This study aimed to validate a new method capable of increasing the accuracy of electrode array placement, reducing channel interaction, electrical artefacts, and saturation effects, and providing the largest number of electrodes that can be activated with the lowest possible electric charge. Materials and methods: Thirty-six subjects aged between 1.42 and 69.92 years were tested during surgery for auditory brainstem implantation. We recorded auditory electrical responses of the brainstem using the implant supplier's suggested stimulation protocol and the new protocol. Results: Saturations effects and electric artefacts were noticed respectively in 81.85% and 53.25% of recordings using implant supplier's method, while in 70.34% and 24.75% of recordings using the new method, with a percentage variation of 11.51% and 28.50%. Considering the amount of charge required to activate the electrodes, with the implant supplier's method an average charge of 14 nC was needed, while with the new protocol an average charge of 8 nC was necessary. Conclusions: The new method improves the coupling between the auditory brainstem implant and the surface of the cochlear nucleus.

Anterior Dislocation After Total Hip Arthroplasty: A Rare Complication

Anterior dislocation after total hip arthroplasty (THA) is a rare event and its treatment protocol is controversial. The most important factor responsible for this complication is malposition of the components. We present a rare case of early anterior dislocation after THA in a 72-year female due to excessive anteverted position of the acetabulum socket as confirmed by radiological evaluation. Closed reduction was not successful. Revision surgery with correction of acetabulum cup version and inclination within the ‘safe zone’ resulted in excellent stability of prosthesis intra-op which even precluded the use of advanced implant designs such as constrained liners. At one-year follow-up, the patient is mobilized with a walking stick and has no recurrence of dislocation. This highlights the role of proper implant positioning which can reduce the complexity of the surgical procedure and provide good functional outcome in such catastrophic events.

Biomolecular, Histological, Clinical, and Radiological Analyses of Dental Implant Bone Sites Prepared Using Magnetic Mallet Technology: A Pilot Study in Animals

Background. A new instrumentation exploiting magneto-dynamic technology (mallet) proposed for implant site preparation was investigated. Methods. In the tibias of three minipigs, two sites were prepared by mallet and two by drill technique. Primary stability (ISQ) was detected after implant positioning (T0) and at 14 days (T14). X-rays and computed tomography were performed. At T14, bone samples were utilized for histological and biomolecular analyses. Results. In mallet sites, histological evaluations evidenced a significant increase in the newly formed bone, osteoblast number, and a smaller quantity of fibrous tissue. These results agree with the significant BMP-4 augmentation and the positive trend in other osteogenic factors (biological and radiological investigations). Major, albeit IL-10-controlled, inflammation was present. For both techniques, at T14 a significant ISQ increase was evidenced, but no significant difference was observed at T0 and T14 between the mallet and drill techniques. In mallet sites, lateral bone condensation was observed on computed tomography. Conclusions. Using biological, histological, clinical, and radiological analyses, this study first shows that the mallet technique is effective for implant site preparation. Based on its ability to cause osseocondensation and improve newly formed bone, mallet technology should be chosen in all clinical cases of poor bone quality.

Image-Free Handheld Robot for Total Knee Arthroplasty Improves Early Functional Recovery Compared with Conventional Total Knee Arthroplasty

This study aimed to examine whether it is advantageous in robotic-assisted TKA (RA-TKA) compared with conventional TKA throughout a 14 postoperative days (PODs). A total of 113 knees (100 patients) were reviewed and divided into the control group (55 knees) and the RA-TKA group (58 knees). We assessed postoperative pain intensity using a visual analogue scale at rest (rVAS) and during movement (mVAS), evaluated lower extremity functional recovery through quadriceps muscle strength and knee range of motion (ROM), preoperatively and on PODs 3, 7, 10, and 14. We also assessed the rescue analgesia intake and postoperative implant coronal alignment. The mean rVAS and mVAS scores did not differ significantly between the two groups. Muscle strength recovery was significantly faster in the RA-TKA group than in the control group on every PODs. ROM recovery was better in the RA-TKA group than in the control group on POD 10. The amount of postoperative analgesia was significantly lower in the RA-TKA group than in the control group. Attainment of a β angle <2° significantly better in RA-TKA. This study demonstrated better functional recovery in RA-TKA, particularly for muscle strength and ROM. RA-TKA reduced rescue drug intake and provided better implant positioning.

Interobserver and Intraobserver Reliabilities of Three-Dimensional Postoperative Evaluation Software in Total Hip Arthroplasty

Background. In primary and revision total hip arthroplasty, to prevent perioperative complications, the prediction of the optimal implant size is essential. Using three-dimensional computed tomography-based postoperative evaluation software, we explored the accuracy and the precision of measurement of the size, alignment, and position of the prosthetic components after total hip arthroplasty. Methods. Using postoperative evaluation software, the postoperative computed tomography data from 20 hips in 20 patients were evaluated. The component size, alignment, and three-dimensional positioning of the cup and stem were assessed. The concordance rates of the component, repeatability (intraobserver reliability), and reproducibility (interobserver reliability) of postoperative evaluation were calculated. The radiographic inclination and radiographic anteversion of the cup, anteversion, varus–valgus angle, and flexion–extension angles of the stem were measured for alignment. The implant positioning was measured along three axes, namely, X-axis (transverse), Y-axis (sagittal), and Z-axis (longitudinal). Results. The concordance rates of all parts are above 94%. The intraobserver and interobserver intraclass correlation coefficients of alignment measurement were very good for both cup (0.879–0.964) and stem (0.973–0.996). The intraobserver and interobserver intraclass correlation coefficients of cup positioning were very good (0.961–0.987) for all axes. The intraobserver and interobserver intraclass correlation coefficients of implant positioning were very good for the stem (0.879–0.995) for all axes. Conclusions. Computed tomography-based postoperative evaluation software was able to evaluate the size and position of total hip implants with high reproducibility.

Functional and radiological assessment of total ankle replacement with infinity prosthesis

Objective: To present mid-term functional and radiological outcomes obtained with the use of Infinity prosthesis in Bogotá (Colombia). Methods: This cross-sectional observational study selected consecutive patients subjected to total ankle replacement with the fourth generation Infinity prosthesis (Wright Medical Technology). Results: Fifty-two patients with ankle arthrosis were followed for a mean period of 24 months, and the most frequently reported case of joint degeneration was trauma. Postoperative improvement was observed in perception of pain (visual analog scale increased from 8/10 to 2/10; p<0.0005), AOFAS functional scale (from 23 to 84.5; p < 0.0005), and range of motion (from 11° to 29°; p<0.0005). Similarly, radiological findings, implant positioning, and signs of loosening did not reveal implant failure. Conclusions: The use of fluoroscopically navigated prostheses allows us to achieve predictable outcomes, with satisfactory mid-term clinical and imaging results. Level of Evidence IV; Therapeutic Studies; Case Series.