Objective To introduce the concept and clinical applications of rotational alignment of the femoral prosthesis in total knee arthroplasty (TKA) so as to avoide the postoperative complications caused by rotational alignment. Methods The clinical and experimental research literature about rotational alignment of the femoral prosthesis in TKA was extensively reviewed and analyzed. Results Femoral prosthesis malrotation can lead to flexion gap unbalanced and undesirable patellar track. Rotation alignment of the femoral prosthesis is defined with radiological and computer assisted technique at pre- and post-operation, which can make the rotation alignment of the femoral prosthesis and the function of the knee favorable. Conclusion In recent years, many surgical skills and new techniques of defining the rotational alignment are developed, and good clinical results are achieved.
The clinical performance and failure issues are significantly influenced by prosthetic malposition in unicompartmental knee arthroplasty (UKA). Uncertainty exists about the impact of the prosthetic joint line height in UKA on tibial insert wear. In this study, we combined the UKA musculoskeletal multibody dynamics model, finite element model and wear model to investigate the effects of seven joint line height cases of fixed UKA implant on postoperative insert contact mechanics, cumulative sliding distance, linear wear depth and volumetric wear. As the elevation of the joint line height in UKA, the medial contact force and the joint anterior-posterior translation during swing phase were increased, and further the maximum von Mises stress, contact stress, linear wear depth, cumulative sliding distance, and the volumetric wear also were increased. Furthermore, the wear area of the insert gradually shifted from the middle region to the rear. Compared to 0 mm joint line height, the maximum linear wear depth and volumetric wear were decreased by 7.9% and 6.8% at –2 mm joint line height, and by 23.7% and 20.6% at –6 mm joint line height, the maximum linear wear depth and volumetric wear increased by 10.7% and 5.9% at +2 mm joint line height, and by 24.1% and 35.7% at +6 mm joint line height, respectively. UKA prosthetic joint line installation errors can significantly affect the wear life of the polyethylene inserted articular surfaces. Therefore, it is conservatively recommended that clinicians limit intraoperative UKA joint line height errors to –2−+2 mm.
ObjectiveTo investigate the risk factors of skin necrosis around incision after total knee arthroplasty (TKA),and explore the measures of prevention and treatment. MethodsBetween June 2007 and June 2013,7 patients with skin necrosis around incision after TKA were treated.There were 5 males and 2 females with an average age of 69 years (range,59-78 years),including osteoarthritis in 4 cases,traumatic arthritis in 2 cases,and rheumatoid arthritis in 1 case.Two cases complicated by diabetes,and 2 cases by hypertension; 1 case received long-term hormone therapy; and 2 cases had a history of smoking.Scar was seen near knee joint in 2 cases.The skin necrosis ranged from 10 cm×2 cm to 13 cm×8 cm.The time from TKA to debridement was 7-15 days (mean,12 days).After thorough debridement,the saphenous artery skin flap,medial head of gastrocnemius muscle flap,lateral head of gastrocnemius muscle flap were used in 4 cases,2 cases,and 1 case respectively; reconstruction of patellar ligament was performed in 2 cases.Donor sites were repaired by split-thickness skin graft. ResultsAll the flaps and myocutaneous flaps survived well,and all wounds healed by first intention.At donor site,the grafted skins survived and wounds healed by first intention.No early complication occurred.All cases were followed up 6-12 months (mean,7.8 months).The flaps and myocutaneous flaps had good texture and appearance; no prosthetic loosening and displacement happened,no secondary infection was observed after operation.The knee range of motion was 45-110° (mean,85°) at 6 months after operation.According to the Knee Society Score (KSS),the results were excellent in 3 cases,good in 2 cases,general in 1 case,and poor in 1 case at 6 months after operation. ConclusionEarly discovery,thoroughly debridement,and timely repair with axial pattern flap or myocutaneous flap are the key factors to treat skin necrosis around incision after TKA and save the artificial prosthesis.
Objective To explore the technique of the soft tissue balancing inthe total knee arthroplasty (TKA) for the patients with the knees of varus deformity and flexion contracture. Methods From January 2001 to December 2005, 86 patients (19 males, 67 females; age, 57-78 years;average, 66 years) with the knees of varus deformity and flexion contracture underwent primary TKA and the balancing of the soft tissues. All the patients had suffered from osteoarthritis. The unibilateral affection was found in 68 patients and the bilateral affection in 18. The varus deformity angle was averaged 12.3° (range, 6-34°). The soft tissue varus accounted for 56.7% and the bony varus accounted for 43.3%. The flexion contracture lt; 10° was found in 21 knees, 10-19° in 45 knees, 20-29° in 22 knees, and gt;30° in 16 knees, with an average angle of 18.9°. Results The flexion contractures were improved. Before operation the average angle ofthe flexion contracture was 18.9° but after operation only 4 patients had a residual flexion contracture of 5° and the remaining patients had a complete correction. The follow-up for 37 months (range, 6-72 months) in all the patients revealed that only 6 patients had a residual flexion contracture of 5-10° and the others had a full extension. Before operation the average varus angle was 12.3°(range, 6-34°) and the average tibiofemoral angle was 174.7° (range, 70.3-175.6°), but after operation the residual varus angle gt; 3° was only found in 2 patients. The complications occurring during operation and after operation were found in 6 patients, injuries to the attachment of the medial collateral ligaments in 2, patellar clunk syndromes in 2, cerebral embolism in 1, and lacunar infarction in 1, with no nerve disorders left after the medical treatment. No skin necrosis, the cut edge infection or deep infection occurred. Conclusion The balancing of the soft tissues is a major management for correction of the varus deformity and the flexion contracture. The proper balancing of the softtissues can achieve an obvious recovery of the function and correction of the varus deformity after TKA.
Objective To observe the posterior condylar offset (PCO) changes and anteroposterior femorotibial translation, to investigate the influence of them on the maximum knee range of flexion (ROF) in patients with posterior cruciatesacrificingself al ignment bearing total knee arthroplasty (TKA). Methods The cl inical data were analyzed retrospectively from 40 patients (40 knees) undergoing primary unilateral TC-PLUSTM SB posterior cruciate-sacrificing self al ignment andbearing TKA for osteoarthritis between January 2007 and June 2009. There were 18 males and 22 females with an average age of 70.6 years (range, 56-87 years). The disease duration was 5-14 years (mean, 9.1 years). The locations were the left side in 11 cases and the right side in 29 cases. Preoperative knee society score (KSS) and ROF were 48.0 ± 5.5 and (77.9 ± 9.0)°, respectively. The X-ray films were taken to measure PCO and anteroposterior femorotibial translation. Multi ple regression analysis was performed based on both the anteroposterior femorotibial translation and PCO changes as the independent variable, and maximum knee flexion as the dependent variable. Results All incisions healed by first intention. The patients were followed up 12-19 months (mean, 14.7 months). At last follow-up, there were significant differences in the KSS (91.9 ± 3.7, t=— 77.600, P=0.000), the ROF [(102.0 ± 9.3)°, t=— 23.105, P=0.000] when compared with preoperative values. Significant difference was observed in PCO (t=3.565, P=0.001) between before operation [(31.6 ± 5.5) mm] and at last follow-up [(30.6 ± 5.9) mm]. At ast follow-up, the anteroposterior femorotibial translation was (— 1.2 ± 2.1) mm (95%CI: — 1.9 mm to — 0.6 mm); femoral roll forward occurred in 27 cases (67.5%), no roll in 1 case (2.5%), and femoral roll back in 12 cases (30.0%). By multiple regression analysis (Stepwise method), the regression equation was establ ished (R=0.785, R2=0.617, F=61.128, P=0.000). Anteroposterior femorotibial translation could be introducted into the equation (t=7.818, P=0.000), but PCO changes were removed from the equation (t=1.471, P=0.150). Regression equation was y=25.587+2.349x. Conclusion Kinematics after TC-PLUSTM SB posterior cruciate-sacrificing self al ignment bearing TKA with posterior cruciate l igament-sacrificing show mostly roll forwardof the femur relative to the tibia, which have a negative effect on postoperative range of motion. There is no correlation between PCO changes and postoperative change in ROF in TC-PLUSTM SB posterior cruciate-sacrificing self al ignment bearing TKA.
ObjectiveTo explore the short- and mid-term effectivenesses of combined unicompartmental knee arthroplasty (UKA) and anterior cruciate ligament (ACL) reconstruction for osteoarthritis (OA) and ACL injury. MethodsBetween January 2006 and January 2014, 32 patients with knee OA and ACL injury were treated by combined UKA and ACL reconstruction. There were 12 males and 20 females, aged 41-63 years (mean, 50 years); 17 left knees and 15 right knees were involved. The causes of ACL injury were sports injury (25 cases) and traffic accident injury (7 cases), including 27 cases of old injury and 5 cases of acute injury. Pain of the medial compartment of the knee and unstable knee joint were the main clinical symptoms. Preoperative X-ray films showed (3.1±0.6)° of varus deformity. ResultsAll incisions healed by first intention, without complication. The patients were followed up 16-112 months (mean, 55 months). Mobile bearing dislocation occurred in 2 cases after operation, and was cured after replacing much thicker mobile bearings. X-ray films showed (4.0±0.7)° of valgus at last follow-up. There was no loosening of the prosthesis. Physiological radiolucent line (<1 mm) was observed around the tibial component in 10 patients. The Oxford Knee Score (OKS), Knee Society Score (KSS) clinical score, KSS functional score, and Tegner activity score at last follow-up were improved significantly (P<0.05). The range of motion (ROM) of the operated knee was (123.5±2.8)°, and the posterior slope of the tibial component was (3.9±1.2)° at last follow-up; a significant correlation was found between ROM and posterior slope according to the Pearson's correlation (r=0.392, P=0.031). ConclusionCombined UKA and ACL reconstruction has good short- and mid-term effectivenesses for OA and ACL injury.
Objective To analyze formation of the varus angle of the knee dueto osteoarthritis and to explore techniques of the soft tissue balance in the total knee arthroplasty(TKA). Methods One hundred patients with145 varus knees (18 males, 25 varus knees; 82 females, 120 varus knees) underwent TKA from January 1999 to December 2003. Their ages averaged 62.4 years (range, 45.80 years), and their HSS（hospital of special surgery）scores were 38.0±3.2 points. Before operation，all the patients were measured in the alignment of the lower extremity, accurate bonecutting was performed, and their static alignment was achieved. Then, the soft tissue release was made. The release performance consisted of 3 steps: release before the bone-cutting, release during the bone-cutting, and release after the bonecutting. Release of themedial ligament and capsule, elimination of the osteophytes, and release of thelateral patellar retinaculum were more important. Results The varus angles in these patients were 9.2±3.1° before operation. Among them,the varus angles caused by the soft tissue imbalance accounted for 53.2%，and caused by the bone structure accounted for 46.8%； and the latter caused by thetibia varus, 22.8%, and by the tibia plateau destruction, 24.0%. There was nosignificant difference between the varus angles caused by the soft tissue imbalance and the varus angles caused by the bone structure deformity (P＞0.05). According to the postoperative imaging studies, the correction degree for the varus angles by the bone-cutting was 4.3°, which represented 27.9% of the total corrected angles, and the correction degree for the varus angles corrected by the soft tissue balance was 10.7°, which represented 72.1% of the total corrected angles. The HSS scores were 87.0±4.5 points after operation, and the difference between preoperation and postoperation was significant. Conclusion The varus knee due to osteoarthritis results from the varus angle in the bone structure and the angles caused by the imbalance of the collateral ligaments and the soft tissues around the knee. The latter causative factor is more important in the formation of the varus knee and should only be corrected through the soft tissue release. The more important part to be released isthe attachments of the medial ligament and the posterior capsule. The release performance should be followed by the principles, i.e., step by step, tests at all the time, and avoidance of the excessive release.
Objective To investigate the effect of lateral retinacular release on the clinical outcomes after total knee arthroplasty (TKA) without resurfacing of the patella. Methods A prospective randomized controlled study was performed on 132 patients with unilateral degenerative knee arthritis undergoing TKA bewteen October 2012 and October 2014, who met the selection criteria. During TKA, lateral retinacular release was used in 66 cases (trial group) and was not used in 66 cases (control group). Two patients were excluded from the study due to missing the follow-up in trial group. Four patients were excluded from the study due to lateral retinacular release in control group. Finally, 64 patients and 62 patients were included in the trial group and in the control group. There was no significant difference in gender, age, body mass index, side, disease duration, preoperative patellar morphology, grading of patellofemoral arthritis, grade of patellar cartilage degeneration, patellar malposition, patellar maltracking, patellar score, and Knee Society Score (KSS) between 2 groups (P>0.05). The operation time, postoperative drainage volume, hospitalization time, postoperative complications, and patient satisfaction were recorded. Postoperative anterior knee pain was assessed by visual analogue scale (VAS), and the knee joint function was evaluated by KSS score and patellar score. The femoral angle, tibial angle, femoral flexion angle, and tibial posterior slope angle were measured on the X-ray film for postoperative prosthetic alignment. The postoperative patellar tracking and patellar position, as well as the presence of osteolysis, prosthesis loosening, patellar fracture and patellar necrosis were observed. Results All patients were followed up for 24 months. There was no significant difference in operation time, postoperative drainage volume, hospitalization time, and patient satisfaction between 2 groups (P>0.05). The incidence of anterior knee pain in the trial group was better than that in the control group (P=0.033). KSS score and patellar score were significantly improved in both groups at 24 months after operation when compared with preoperative scores (P<0.05), but no significant difference was found between 2 groups (P>0.05). Complications included hematoma (2 cases in the trial group, and 1 case in the control group), mild wound dehiscence (2 cases in each group respectively), skin-edge necrosis (1 case in the trial group), and superficial wound infection (1 case in each group respectively), which were cured by conservative treatment. No patellar necrosis, patella fracture, or knee lateral pain occurred in 2 groups. There was no significant difference in complication rate between groups (P=0.392). Satisfactory implant alignment was observed in both groups during follow-up. There was no significant difference in femoral angle, tibial angle, femoral flexion angle, and tibial posterior slope angle between 2 groups (P>0.05). No radiolucent line at the bone-implant interface was seen around the tibial components and femoral components in both groups. The patellar maltracking was observed in 3 patients of the trial group and 5 patients of the control group, showing no significant difference (P=0.488). However, the incidence of patellar malposition in the trial group (18.8%) was significantly lower than that in the control group (35.5%) (χ2=0.173,P=0.034). Conclusion Lateral retinacular release during primary TKA without resurfacing of the patella can reduce postoperative knee pain without increasing complications.
ObjectiveTo evaluate the effectiveness of reduction osteotomy for correction of varus knee during total knee arthroplasty. MethodsA retrospective analysis was made on the clinical data of 16 patients (24 knees) who received reduction osteotomy for correcting varus knee during total knee arthroplasty between May 2010 and July 2012. There were 2 males (3 knees) and 14 females (21 knees), with an average age of 67 years (range, 57-79 years). The disease duration ranged from 3 to 15 years (mean, 9.1 years). The Knee Society Score (KSS) was 38.71±10.04 for clinical score and 50.31±14.31 for functional score. The range of motion (ROM) of the knee was (91.88±13.01)°. The tibiofemoral angle was (9.04±4.53)° of varus deformity. Reduction osteotomy was applied to correct varus knee. ResultsThe operation time was 85-245 minutes (mean, 165.5 minutes); the obvious blood loss was 10-800 mL (mean, 183.1 mL); the hospitalization time was 8-22 days (mean, 13.6 days). All incisions healed by first intention. No neurovascular injury or patellar fracture occurred. The follow-up duration ranged from 37 to 62 months (mean, 48 months). The tibiofemoral angle was corrected to (3.92±1.89)° of valgus at 48 hours after operation. The lower limb alignment recovered to normal. The X-ray films showed no evidence of obvious radiolucent line, osteolysis, or prosthesis subsidence. The results of KSS were significantly improved to 84.21±6.49 for clinical score and 85.31±6.95 for functional score (t=20.665, P=0.000; t=9.585, P=0.000); and ROM of the knee was significantly increased to (105.83±11.29)° (t=8.333, P=0.000) at last follow-up. ConclusionThe effectiveness of reduction osteotomy for varus knee deformity during total knee arthroplasty is satisfactory. Proper alignment, ROM, and function of knee can be achieved.
Objective To conduct a systematic bibliometric analysis of recent research on robot-assisted orthopedic surgery, in order to reveal the research trends, hotspots, main contributors, and future development directions in this field. Methods On August 27, 2024, WoSCC (Web of Science Core Collection Database) was searched and relevant literature on robot-assisted orthopedic surgery from 2003 to 2023 was included. Excel 2016, VOSviewer (version 1.6.10), and CiteSpace (version 6.2.R6) were used for data collection and analysis. Results The total citation frequency of 1718 retrieved literature was 28978 times, with an average citation frequency of 16.87 times per article. The total citation frequency of articles in 2019 was the highest (4330 times), and the publication volume in 2023 was the highest (315 articles). Among the top 5 countries in terms of publication volume, the United States had the highest publication volume and total citation frequency, while China ranked second in terms of publication volume, but had the lowest average citation frequency per article. Analysis of cooperation between countries showed that the United States, China, Germany, and other countries had the most cooperation. Babar Kayani’s articles were cited the most frequently. Among the top 10 institutions in terms of publication volume, the Hospital for Special Surgery (United States) had the highest publication volume, the Pennsylvania State System of Higher Education (United States) had the highest total citation frequency for publications, and the average citation frequency of each article published by the University of Pittsburgh (United States) was the highest. The dynamic evolution of research hotspots suggested that early research mainly focused on the combination of traditional surgical techniques and navigation, while in recent years, research had mainly focused on computer-aided surgery, augmented reality, and medical robotics technology. Conclusions In recent years, significant progress has been made in the research of robot-assisted orthopedic surgery, with the United States taking a leading position in this field and having extensive global cooperation. Research hotspots show that with the continuous development of computer-aided surgery, augmented reality, and robotics technology, the field of orthopedic surgery is evolving towards more precise, individualized, and minimally invasive directions.