Intraoperative Neurophysiological Monitoring in Total Hip Arthroplasty for Crowe Types 3 and 4 Hips.

Background: Crowe types 3 and 4 dysplastic hips usually need total hip arthroplasty (THA) with femoral shortening osteotomy (FSO) to facilitate reduction, equalize limb length, and decrease the traction stress in nerves. The frequency of peripheral nerve palsy after primary THA has been reported to range from 0.08% to 3.7%. Apart from direct trauma to the nerve, the excessive extension of the extremity is also reported as a common cause of nerve damage. The current study aimed to evaluate the outcomes of intraoperative neurophysiological monitoring (IONM) in THA for Crowe types 3 and 4 hips. Methods: The data of patients who underwent primary THA with IONM were retrospectively reviewed using our medical records. Patients with Crowe types 3 and 4 dysplastic hips were included in the study. Motor-evoked potentials and somatosensory-evoked potentials were assessed intraoperatively. Preoperative dislocation height and postoperative trochanter minor differences were measured using preoperative and postoperative radiographs. Results: Twenty-three hips of 19 patients (4 bilateral THAs) with a mean age of 45 years participated in the study. Ten hips (43%) were classified as Crowe type 4, whereas 13 hips (57%) were Crowe type 3. The mean preoperative dislocation height was 41.6 mm (range, 15-100 mm). Postoperatively, only 6 patients had a difference between trochanter minor levels with a mean of 8.5 mm (range, 3-17 mm). Three patients underwent a subtrochanteric FSO to achieve reduction. Postoperatively, no patient had any motor and sensory nerve dysfunction. Conclusions: According to the results acquired from this study, no nerve palsy was observed after THA for Crowe types 3 and 4 hips, and subtrochanteric FSO was not performed in all Crowe type 3 hips and 70% of Crowe type 4 hips with the aid of IONM.

A comparison of robotic-assisted and manual techniques in restricted kinematically aligned total knee arthroplasty: coronal alignment improvement with no significant clinical differences.

PURPOSE: The purpose of this study was to compare radiographic and clinical outcomes of robotic-assisted and conventional manual techniques in restricted kinematically aligned TKA. METHODS: Patients who underwent either manual or robotic-assisted restricted kinematically aligned TKA between 2019 and 2020 were included in this retrospective comparative study. Radiographic outcomes comprised coronal plane measurements performed through standing full-length anteroposterior radiographs. The Knee Injury and Osteoarthritis Outcome Score (KOOS), Oxford score, Visual Analog Scale pain and satisfaction score, and Forgotten Joint Score were used to determine the clinical outcome. The continuous data were compared by Student's t test according to the Kolmogorov‒Smirnov normality test. RESULTS: The manual group consisted of 46 patients (38 females, eight males) with a mean age of 68.1 years, and the robotic group consisted of 70 patients (58 females, 12 males) with a mean age of 65.7 years (n.s.). Preoperatively, no significant difference was observed between groups concerning demographic characteristics, radiographic measurements, and clinical scores except for the symptom and pain domains of the KOOS score, which was significantly worse in the manual group (p = 0.011 and 0.035, respectively). At the postoperative 2-year follow-up, we observed significant differences between groups with respect to the mean HKA angle, mMPTA, and mLDFA (p = 0.034, 0.041, and 0.005, respectively). A comparison of clinical scores at the postoperative 2-year follow-up demonstrated no significant differences between groups. CONCLUSION: The current study demonstrated that using robotic-assisted technique for restricted kinematically aligned total knee arthroplasty (TKA) resulted in significantly better outcomes compared to the conventional manual technique in achieving normal ranges of lower extremity coronal alignment measurements. While the robotic-assisted group demonstrated better clinical scores, there was no statistically significant difference in clinical outcomes between the robotic-assisted group and the control group at the two-year follow-up. Concerning clinical relevance, the restoration of original anatomy and coronal alignment, a crucial concern in restricted kinematically aligned TKA, may be better achieved by the robotic-assisted technique. LEVEL OF EVIDENCE: Level III (Retrospective cohort study).

Preliminary outcomes of kinematically aligned robot-assisted total knee arthroplasty with patient-specific cartilage thickness measurement.

This study aimed to assess the preliminary outcomes of kinematically aligned robot-assisted total knee arthroplasty (TKA) with patient-specific cartilage thickness measurement. Patients who underwent kinematically aligned robot-assisted TKA were included in this study. Robot-assisted total knee arthroplasties were performed by NAVIO Surgical System (Smith & Nephew, Memphis, USA), an image-free handheld robotic system. The kinematic alignment technique was performed according to our intraoperative cartilage thickness measurement technique. Hip-knee-ankle angle (HKA), mechanical lateral distal femoral angle (mLDFA), mechanical medial proximal tibial angle (mMPTA), joint-line orientation angle (JLOA), and joint-line convergence angle (JLCA) were measured through standing full-length anteroposterior radiographs. Knee Injury and Osteoarthritis Outcome Score, Oxford score, VAS pain and satisfaction score, and Forgotten Joint Score were used to assess clinical outcomes. A total of 142 knees of 109 patients (92 females and 17 males) were evaluated in this study. There was a significant correction in HKA, JLCA, and mMPTA postoperatively (p ≤0.001, < 0.001, and 0.029, respectively). We observed no significant change in mLDFA and JLOA measurements. All clinical scores significantly increased at the latest follow-up. Our results demonstrated that kinematically aligned robot-assisted TKA with patient-specific cartilage thickness measurement demonstrated no significant change in mLDFA and JLOA, as expected; however, significantly corrected the deformity in HKA, mMPTA, and JLCA measurements.

Biomechanical Comparison of Polymethylmethacrylate Augmentation Methods in Failed Pedicle Screw Revision.

AIM: To compare biomechanical results between different polymethylmethacrylate (PMMA) augmentation methods on failed lumbar pedicle screw models of animal vertebrae. MATERIAL AND METHODS: Thirty lumbar vertebrae were harvested from six calves, and their bone mineral density was measured. 60 Polyaxial pedicle screws were inserted to all vertebrae. Pull-out tests were performed to all specimens on an Instron machine. The specimens were randomly divided into four groups. The same screws used in primary screwing process were labeled and used in revision. Screws in the first group were augmented by injecting PMMA into the failed screw hole with a syringe; screws in the second group by inserting bone graft and roll-shaped PMMA, screws in the third group by inserting bone graft and injecting PMMA with a syringe; and the fourth group by inserting bone graft and injecting PMMA through a fenestrated pedicle screw. The pull-out strength (POS) results of all specimens were recorded and compared with statistical analyses. RESULTS: The mean BMD of the vertebrae was 1.31 ± 0.225 g/cm < sup > 2 < /sup > and no significant difference was found between the groups (p > 0.05). The mean POS of the primary screws in the first, second, third, and fourth groups were 2166,5 N/m < sup > 2 < /sup > , 2183,5 N/m2, 2508,5 N/m < sup > 2 < /sup > , and 2005c N/m < sup > 2 < /sup > respectively. After the augmentation, the mean POS in the first, second, third and fourth groups were 3839 N/m < sup > 2 < /sup > , 2874 N/m < sup > 2 < /sup > , 2929 N/m < sup > 2 < /sup > and 3826 N/m < sup > 2 < /sup > respectively. No statistical difference was found between the groups in post-revision POS values (p > 0.05). CONCLUSION: There was no significant statistical difference found in POS between the augmentation methods.