Robot assisted surgery is becoming a widely popular technology and is now entering the total knee replacement. The development of total knee replacement and the operation system structure are introduced in this paper. The vision position technology and the related calibration technology, which are very important, are also analyzed. The experiments of error analysis in our WATO system demonstrate that the position and related calibration technologies have a high precision and can satisfy surgical requirement.
Arthroplasty, Replacement, Knee ; instrumentation ; methods ; Humans ; Pattern Recognition, Automated ; methods ; Robotics ; instrumentation ; Surgery, Computer-Assisted ; instrumentation ; methods

OBJECTIVE: To analyze the conventional application of using comprehensive hemostatic methods during the perioperative period, and the effect of autologous blood transfusion (ABT) device compared with non-negative pressure drainage on preventing blood loss and allogenic blood transfusion after primary total knee arthroplasty (TKA). METHODS: A total of 131 patients (131 knees) with severe knee osteoarthritis who underwent unilateral primary TKA by the same surgeon in Peking University Third Hospital from June 2014 to June 2015 were enrolled in this study. The patients were divided into ABT group (64 patients) and control group (67 patients). ABT devices were used for drainage and blood transfusion in the ABT group while the control group used the non-negative pressure drainage only. The results of the drainage fluid volume, the decrease of hemoglobin, the total blood loss, the hidden blood loss and blood transfusion after TKA were compared between the two groups. RESULTS: The drainage fluid volume in ABT group was significantly higher than that in control group [515 mL (80-1 610 mL) vs. 260 mL (40-670 mL), P<0.001]. The autologous blood transfusion in ABT group was 245 mL (60-1 070 mL). There were no significant differences between the two groups in the value of hemoglobin decrease 1 day after surgery (P=0.340) and 3 days after surgery (P=0.524). There were no significant differences in the total blood loss (P=0.101) and the hidden blood loss (P=0.062) between the two groups either. There were 9 patients in the 131 patients who received allogeneic blood transfusion, of whom 5 in the ABT group (5/64, the blood transfusion rate was 7.8%) and 4 in the control group (4/67, the blood transfusion rate was 6.0%), and no significant differences in the blood transfusion rate between the two groups (P=0.943). CONCLUSION With the conventional application of using comprehensive hemostatic methods during perioperative period, the ABT device did not show the effective result of controlling postoperative blood loss and failed to reduce the rate of allogeneic blood transfusion in patients with unilateral primary TKA. However, the ABT device could increase the drainage fluid volume and improve the patient's hospitalization expenses. Therefore, there is no need for routine application of ABT device in unilateral primary TKA.
Arthroplasty, Replacement, Knee ; Blood Loss, Surgical/prevention & control* ; Blood Transfusion ; Blood Transfusion, Autologous/instrumentation* ; Hemostatics ; Humans

BACKGROUND: The efficacy of saline-coupled bipolar sealing devices in joint arthroplasty is uncertain, and the utility in simultaneous bilateral total knee arthroplasty (TKA) has not been reported. METHODS: This study compares the use of bipolar sealing and conventional electrocautery in 71 consecutive patients. The experimental and control groups were matched for age, sex, body mass index, American Society of Anesthesiologists (ASA) classification, and preoperative hemoglobin. Variables of interest included blood loss, transfusion requirements, and operative characteristics. RESULTS: In comparison to patients treated with conventional electrocautery, those treated with the bipolar sealer were 35% less likely to require transfusion. The median number of transfusions per case was also significantly lower in the experimental group. Hemoglobin change, total blood loss, and length of stay were not significantly different between the groups. The experimental group had longer operative times. CONCLUSIONS: Bipolar sealing shows promise as a blood loss reduction tool in simultaneous bilateral TKA. The marginal savings attributed to reduced transfusion rates with use of the bipolar sealer did not exceed the additional per-case expense of using the device. The decision to use the device with the goal of less blood loss must come with the additional expense associated with its use.
Adult ; *Arthroplasty, Replacement, Knee ; Blood Loss, Surgical/*prevention & control ; Catheter Ablation/instrumentation ; Electrocoagulation/*instrumentation ; Female ; Humans ; Male

Finding the position of caput femoris center by exact and fast method is a key technique in total knee replacement navigation surgery. A method for finding the position of caput femoris center is described in this paper. The main idea is abstracting this problem to a geometrical model in which the center of a sphere can be easily worked out with a few known spherical points. Experiments show that the method is feasible and the precision satisfies the requirements of navigation surgery.
Algorithms ; Arthroplasty, Replacement, Knee ; instrumentation ; methods ; Biomechanical Phenomena ; Computer Simulation ; Humans ; Models, Biological ; Surgery, Computer-Assisted ; instrumentation ; methods

Artificial knee joint simulation test is an important form in the research and evaluation of prosthetic material and design. Natural knee joint could not be tested by conventional instruments because of complex motion and load in movement. Simulation test designed for artificial knee is needed. At present, two kinds of simulation, namely simplification method and complete simulation, are widely used. Complete simulation can be used for simultaneous evaluation of material and design of prosthesis, whereas simplification method is only useful in evaluating the material of prosthesis. In international standards, there are already two protocols for artificial knee joint experiment, namely load control and displacement control. This paper also reviews the evaluation criteria and measurement standards for artificial knee joint simulation test, and then envisages the researches in future.
Arthroplasty, Replacement, Knee ; instrumentation ; Computer Simulation ; Computer-Aided Design ; Equipment Failure Analysis ; methods ; Humans ; Knee Prosthesis ; Prosthesis Design ; methods

BACKGROUND: Clinical and radiologic evaluation and analyses of the surgeries using Buechel and Pappas (B-P) knee implants. METHODS: The study was conducted on 60 patients who underwent 94 total knee replacement arthroplasty with B-P knee implants from May 2009 to December 2010. The results were compared to the results of 41 patients who underwent 60 knee joint surgeries using NexGen-LPS implants from January 2008 to August 2009. RESULTS: The American Knee Society score of the B-P knee group increased from an average of 66.9 (clinical score) and 65.5 (functional score) to 93.4 and 90.3, respectively; while those for the NexGen-LPS group increased from an average of 68.8 (clinical score) and 62.4 (functional score) to 86.3 and 76, respectively. The average ranges of motion of the B-P knee group and the NexGen-LPS group were 119.1degrees and 114.8degrees, respectively, before surgery and improved to 121.0degrees and 123.0degrees at final follow-up after the surgery. The visual analogue scale scores for the B-P knee group and the NexGen-LPS group improved from 4.7 and 4.6 to 1.4 and 1.8, respectively. The flexion contracture also improved from 5.1degrees and 6.3degrees to 0.64degrees and 1.72degrees. The tibio-femoral angle for the B-P knee group and the NexGen-LPS group also improved greatly after the surgery, from varus 0.34degrees and 0.73degrees each to valgus 6.7degrees and 6.9degrees, respectively. CONCLUSIONS: The evaluation of more than 2 years of total knee replacement arthroplasty using B-P knee implants showed good results. B-P knee implants showed a relatively higher degree of satisfaction in clinical knee score and less intraoperative bone mass removal than NexGen-LPS implants.
Aged ; Aged, 80 and over ; Arthroplasty, Replacement, Knee/*instrumentation ; Female ; Follow-Up Studies ; Humans ; Knee Joint/radiography/*surgery ; *Knee Prosthesis ; Male ; Middle Aged ; Osteoarthritis, Knee/radiography/*surgery

INTRODUCTIONThe use of robotics in total knee arthroplasty (TKA) has been shown to minimise human error, as well as improve the accuracy and precision of component implantation and mechanical axis alignment. The present study aimed to demonstrate that robot-assisted TKA using ROBODOC® is safe and capable of producing a consistent and accurate postoperative mechanical axis.

METHODSWe prospectively recruited 27 consecutive patients who underwent robot-assisted TKA between May and December 2012. Two patients were excluded from the study due to intraoperative technical problems with the robot. Long-leg radiography and computed tomography were performed prior to surgery, and used for mechanical axis measurements and component sizing. DigiMatch™ ROBODOC® Surgical System software version 4.3.6 (Curexo Technology Corp, Fremont, CA, USA) was used in all cases to perform bone cuts in accordance with the preoperative plan.

RESULTSThe postoperative coronal mechanical alignment was within 3 degrees, with a mean alignment of -0.4 ± 1.7 degrees, confirming the accuracy of the preoperative surgical plan and bone cuts. The mean operating time was 96 ± 15 min, and preoperative planning yielded 100% implant sizing accuracy.

CONCLUSIONRobotics has the potential to enable surgeons to consistently attain ideal postoperative alignment. The use of bone movement monitors and an integrated navigation system enhances the safety profile of ROBODOC® by minimising errors. However, the role of the surgeon in TKA is still vital, as the surgeon is ultimately in charge of planning the surgery, its execution and ensuring soft tissue balance during TKA.

Aged ; Arthroplasty, Replacement, Knee ; instrumentation ; Female ; Humans ; Knee Joint ; diagnostic imaging ; Male ; Middle Aged ; Prospective Studies ; Robotic Surgical Procedures ; instrumentation ; Tibia ; surgery ; Tomography, X-Ray Computed

OBJECTIVETo compare clinical efficacy of individual osteotomy instrument and total knee arthrolplasty (TKA) in treating patients with knee osteoarthritis.

METHODSFrom June 2014 to December 2014, 40 patients with unilateral knee osteoarthritis were randomly divided into two groups and 20 cases were in each group. One group (individual group) were treated with TKA with individual osteotomy instrument,including 5 males and 15 females with an average age of (67.3 ± 6.5) years old; 8 cases on the left side and 12 cases on the right side. Another group (conventional group) were treated with conventional TKA , including 6 males and 14 females with an average age of (66.8 ± 7.3) years old; 9 cases on the left side and 11 cases on the right side. Operative time, blood loss, postoperative HSS score at 6 months, and changes of mechanical alignment before and after operation were analyzed.

RESULTSOperative time in individual group was (79.3 ± 4.7) min, and (83.5 ± 3.2) min in conventional group; blood loss in individual group was (287.1 ± 24.9) ml and (363.4 ± 47.2) ml in conventional group, there were statistical differences between two groups in these two items. There was no significant difference in postoperative HSS score at 6 months between individual group (84.8 ± 3.2) and conventional group (84.2 ± 2.5). Postoperative limb alignment in individual group was (2.8 ± 0.6)°, and (2.8 ± 0.6)° in conventional group, with no significant difference between two groups.

CONCLUSIONTKA with individual osteotomy instrument could reduce operative time and blood loss, but there was no differences in knee function, changes of mechanical alignment compared with TKA.

Adult ; Aged ; Arthroplasty, Replacement, Knee ; methods ; Case-Control Studies ; Female ; Humans ; Knee Joint ; surgery ; Male ; Operative Time ; Osteoarthritis, Knee ; surgery ; Osteotomy ; instrumentation ; methods ; Treatment Outcome

OBJECTIVETo summarize experience of using screws and cement to rebuild tibial bone defect in primary total knee arthroplasty (TKA) and to discuss the relationship between the number of required screws and the severity of tibial bone defects.

METHODSFrom July 2009 to May 2015, 34 patients (40 knees) with varus knees underwent TKA, and the screw and cement technique was used to rebuild medial tibia plateau during operation. There were 8 males (8 knees) and 26 females (32 knees), and the average age was (65.00 +/- 7.25) years old (ranged,55 to 82 years old). One to 6 screws were used in each case. Extension stems were used in 2 cases (4 and 5 screws was used respectively). The area percentages of the bone defects measured as defect area/tibia plateau area, depth of each defect, the number of screws needed in each case, were all used to determine the relationship between the number of screws and the area percentage in certain depth of bone defect by statistic methods, as well as the relationship between screw number and defect depth.

RESULTSAll the patients were followed up and the average duration was 24 months (ranged, 1 to 72 months). The average preoperative HSS score was 43.33 +/- 6.11 (ranged, 32 to 51 scores). Whereas the average postoperative HSS score was 92.15 +/- 4.64 (ranged,83 to 96 scores). The preoperative individual scores including pain, function, activity, nuscle strength, flexion deformity and stability were all improved compared with preoperation,and the differences were statistically significant. All the patients received normal alignment postoperatively, femoraltibial angle was improved from (167.00 +/- 6.39) degrees preoperatively to (175.00 +/- 2.69) degrees postoperatively, the tibial angle was improved from (78.09 +/- 4.51) degrees preoperatively to (88.75 +/- 1.24) degrees postoperatively. Both area percentage and depth of bone defect in a fitting Ologistic model had a significant statistical relationship with the screw number, and a rectangular coordinate system could be formed according to the relationship.

CONCLUSIONScrews and cement technique is a simple, safe and convenient method to rebuild tibial bone defects in primary TKA and its short-term and midterm effect are both reliable. During opera- tion, according to the rectangular coordinate system, the screw number needed in the operation can be inferred form th area and depth of tibia defect, which could have a guiding function in surgery.

Aged ; Aged, 80 and over ; Arthroplasty, Replacement, Knee ; instrumentation ; methods ; Bone Screws ; utilization ; Female ; Fracture Fixation, Internal ; Humans ; Knee Injuries ; surgery ; Knee Joint ; surgery ; Male ; Middle Aged ; Tibia ; surgery

OBJECTIVETo compare the preliminary effectiveness of mobile-bearing prosthesis and fixed-bearing prosthesis by literature review and observation of cases.

METHODSNinety-eight knees of 94 patients undergoing total knee arthroplasty (TKA) by using cemented and PCL-substitute prosthesis were reviewed from February 2003 to October 2004. The diagnosis of all patients were osteoarthritis. All cases were followed up at least one year. Group A (fixed-bearing prosthesis): 30 knees of 29 patients, 4 males, 25 females, 20 DePuy Prosthesis, 10 Centerpulse Prosthesis. Group B (mobile-bearing prosthesis): 68 knees of 65 patients, 11 males, 54 females, 68 Centerpulse Prosthesis. Make sure statistical comparability between 2 groups by HSS, age and gender, respectively. Postoperation 6 weeks, 3 months, 6 months, 1 year, all cases were evaluated according to Hss and self-satisfaction.

RESULTSThe grades of Hss in different stage were performed statistical analysis. P value in different stage was 0.414 (6 weeks), 0.108 (3 months), 0.235 (6 months), 0.452 (1 year). There were no significant difference between group A and B in different stage by statistical analysis. In one year after operation, the range of motion in 2 groups, group A: 108 degrees (95 degrees - 118 degrees), group B: 107 degrees (90 degrees - 120 degrees), there were no significant difference by ROM (P > 0.05). At the latest follow-up examination, group A: 13.7% of the patients (4 knee joint) complained mild pain, the percent of the patients' self-satisfaction was 90%; group B: 13.1% of the patients (9 knee joint) complained mild pain, the percent of the patients' self-satisfaction was 88%.

CONCLUSIONSAlthough it is certain about the effectiveness of preliminary clinical outcomes with mobile-bearing prosthesis, it is still uncertain about the advantage of mobile-bearing prosthesis over fixed-bearing prosthesis. The reason for preferring to the former still need being demonstrated.

Aged ; Arthroplasty, Replacement, Knee ; instrumentation ; Female ; Follow-Up Studies ; Humans ; Knee Prosthesis ; Male ; Middle Aged ; Osteoarthritis, Knee ; surgery ; Retrospective Studies ; Treatment Outcome