Objective To evaluate the early effectiveness and summarize the initial application experiences of Mako robot-assisted total hip arthroplasty (THA) for developmental dysplasia of the hip (DDH) in adults. Methods Between August 2018 and January 2020, 55 cases of DDH (75 hips) were treated with Mako robot-assisted THA. There were 10 males and 45 females with an average age of 51 years (range, 30-73 years). There were 35 cases of unilateral hip and 20 cases of bilateral hips. The DDH was classified as Crowe type Ⅰin 29 hips, type Ⅱ in 20 hips, type Ⅲ in 6 hips, and type Ⅳ in 20 hips. The modified Harris score was 54.8±16.0, the hip joint range of motion was 90° (80°, 100°), and the leg length discrepancy (LLD) was 22.0 (10.5, 47.0) mm. The preoperative surgical plan was made in the robot system based on the CT data. The reaming and installation of the acetabular cup were completed with the assistance of the robot system. The distance between the rotation center of the hip joint and the teardrop (horizontal distance, vertical distance), inclination angle, and anteversion angle were measured on the pelvic X-ray film to evaluate the position of the acetabular prosthesis. The above indicators were compared with preoperative planning to evaluate the accuracy of robotic-assisted surgery. The modified Harris score, the range of motion, and the LLD were used to evaluate the early effectiveness. Results The 75 hips of THAs were completed with the assistance of Mako robots. There was no significant difference in the acetabular inclination angle, the horizontal distance and the vertical distance of the rotation center between the preoperative planning and the postoperative measurement values (P>0.05); the acetabular anteversion angle was significantly smaller than the postoperative measurement value (t=–2.482, P=0.015). Four hips located beyond the Lewinnek safety zone, and 71 hips located within the Lewinnek safety zone. All patients followed up 6-24 months (mean, 13 months). All incisions healed by first intention. At last follow-up, the modified Harris score was 85.5±11.2, the hip joint range of motion was 120° (110°, 120°), and the LLD was 3.8 (2.0, 8.1) mm; all improved significantly compared with preoperative ones (P<0.05). Except for one nerve injury case, there was no other complication. Conclusion Mako robot-assisted THA is a safe and effective method for adult DDH, which can optimize the acetabular cup positioning, hip function, and leg length, but the long-term effectiveness needs to be confirmed by further studies.
ObjectiveTo evaluate the early effectiveness of the robot-assisted total hip arthroplasty (THA) via direct superior approach (DSA).MethodsBetween March 2021 and April 2021, 11 patients (11 hips) were treated with a robot-assisted THA via DSA. There were 7 males and 4 females, with an average age of 55 years (range, 26-73 years). There were 5 patients of osteoarthritis secondary to hip dysplasia and 6 patients of osteonecrosis of femoral head. Preoperative hip Harris score was 55.8±6.3. The operation time, volume of blood loss, length of incision, postoperative blood transfusion and hospital stay, and the incidence of surgical complications were recorded. The visual analogue scale (VAS) score and Harris score were used to evaluate hip joint pain and function. The leg length discrepancy (LLD) was measured on the X-ray films. The inclination angle and anteversion angle of the acetabular component were also measured, and the difference between the planned and actual values were compared.ResultsOne THA was performed via conventional posterolateral approach finally because of poor exposure. The rest of 10 THAs were performed with assistance of robotic arm via DSA. The average operation time was 89 minutes (range, 65-120 minutes); the average length of incision was 10.5 cm (range, 9-13 cm); and the average blood loss was 400 mL (range, 110-740 mL). One patient was given a blood transfusion for 2 unit. All incisions healed by first intention and no neurovascular injury, deep vein thrombosis, or fracture occurred. The length of hospital stay after operation was 2-6 days (mean, 4.4 days). The duration of follow-up was 1-3 months (mean, 2.1 months). The VAS score was 0 in 9 patients and 2 in 1 patient at the day of discharge. At last follow-up, the hip Harris score was 84.9±6.7, showing significant difference when compared with that before operation (t=−8.717, P=0.000). The inclination and anteversion angles were (37.4±2.0)° and (17.1±4.5)°, respectively, and there was no significant difference when compared with the planned values [(38.2±1.6)°, (16.6±3.7)°] (t=1.809, P=0.104; t=–1.103, P=0.299). The LLD ranged from –2 to 4 mm. No complication such as dislocation, aseptic loosening, or periprosthetic joint infection occurred. ConclusionThe robot-assisted THA via DSA has encouraged early effectiveness.
Objective To compare the difference in the inclination and anteversion angles of the acetabular cup measured by intraoperative robot-assisted total hip arthroplasty (THA) and postoperative X-ray films and CT imaging. MethodsThe clinical data of 54 patients (54 hips) who underwent robot-assisted THA between May 2020 and December 2020 were retrospectively analyzed. Among them, there were 26 males (26 hips) and 28 females (28 hips), with an average age of 58.4 years (range, 39-71 years). The body mass index was 19.2-29.3 kg/m2, with an average of 25.2 kg/m2. All the patients had their first THA, including 31 cases of osteonecrosis of the femoral head, 12 cases of hip arthritis, 8 cases of femoral neck fracture, and 3 cases of developmental dysplasia of the hip. The anteversion and inclination angles of the acetabular cup were obtained through the surgical data in the robot host system. All patients underwent X-ray and CT scan examination within 2-7 days after operation to obtain the postoperative anteversion and inclination angles of the acetabular cup. According to the concept of “Lewinnek safe zone”, the proportion of acetabular in the safe zone intra- and post-operation were compared. ResultsThe operation time was 57.8-89.2 minutes, with an average of 68.3 minutes; the intraoperative blood loss was 125.0-450.0 mL, with an average of 204.8 mL. No adverse events such as dislocation of hip joint and infection occurred during hospitalization. The anteversion angle of acetabular cup was (40.8±0.6)° during operation and (41.2±2.8)° after operation, with no significant difference (t=1.026, P=0.307). The anteversion angle of acetabular cup measured during operation was (17.6±1.4)°, which was significantly smaller than that measured after operation (23.4±3.8)°(t=10.520, P=0.000). According to “Lewinnek safe zone”, 54 hips (100%) were in the safety zone during operation, and 16 hips were out of the safety zone, 38 hips were in the safty zone after operation, the ratio of the hips in the safty zone was 70.4%, showing a significant difference (χ2=18.783, P=0.000). ConclusionRobot-assisted THA can obtain accurate placement of the acetabular cup, but there is a large deviation between the anteversion angle of the acetabular cup in the lateral position during operation and the supine position after operation. Further study is needed to define the intraoperative placement position of the acetabular cup.