Objective To investigate a modified robotized hydraulictensor for management of the ligament balance in the total knee arthroplasty. Methods The effect of the modified robotized hydraulic tensor on the mechanical behaviour of the ligament system balance in the total knee arthroplasty was analyzed andthe related information was obtained. Results The robotized hydraulic tensor acted as a tensorsensor system, which could assist the surgeon by providing thequantitative information to align the lower limb in extension, equalize the articular spaces in extension and flexion, balance the internal and external forces, and define the femoral component rotation, and by providing the information toplan the releasing of the soft tissues and the rotating of the femoral component. Conclusion The modified robotized hydraulic tensor can enable the surgeon to properly manage the ligament balance in the total knee arthroplasty.
The surgical installation accuracy of the components in unicompartmental knee arthroplasty (UKA) is an important factor affecting the joint function and the implant life. Taking the ratio of the medial-lateral position of the femoral component relative to the tibial insert (a/A) as a parameter, and considering nine installation conditions of the femoral component, this study established the musculoskeletal multibody dynamics models of UKA to simulate the patients’ walking gait, and investigated the influences of the medial-lateral installation positions of the femoral component in UKA on the contact force, joint motion and ligament force of the knee joint. The results showed that, with the increase of a/A ratio, the medial contact force of the UKA implant was decreased and the lateral contact force of the cartilage was increased; the varus rotation, external rotation and posterior translation of the knee joint were increased; and the anterior cruciate ligament force, posterior cruciate ligament force and medial collateral ligament force were decreased. The medial-lateral installation positions of the femoral component in UKA had little effect on knee flexion-extension movement and lateral collateral ligament force. When the a/A ratio was less than or equalled to 0.375, the femoral component collided with the tibia. In order to prevent the overload on the medial implant and lateral cartilage, the excessive ligament force, and the collision between the femoral component and the tibia, it is suggested that the a/A ratio should be controlled within the range of 0.427?0.688 when the femoral component is installed in UKA. This study provides a reference for the accurate installation of the femoral component in UKA.
ObjectiveTo evaluate the effect of the surgeon’s handedness on the distribution of prosthesis during primary total knee arthroplasty (TKA).MethodsA retrospective analysis was performed on 86 patients (100 knees) with primary TKA completed by the same right-handed surgeon between December 2016 and December 2018, including 72 cases of single knee and 14 of bilateral knees. The patients were divided into dominant group (right side) and non-dominant group (left side) according to the operating position of the surgeon and each group had 50 knees. There was no significant difference in gender, age, body mass index, disease duration, clinical diagnosis, preoperative Hospital for Special Surgery (HSS) score, and other general data between the two groups (P>0.05). The operation time and complications were recorded in both groups. The function of knee was evaluated by HSS score. Hip-knee-ankle angle (HKA), mechanical lateral distal femoral angle (mLDFA), and mechanical medial proximal tibial angle (mMPTA) were measured by using X-ray film of full-length lower extremity before TKA and at 2 weeks after TKA that were used to evaluate the coronal position of the prosthesis. Posterior distal femoral angle (PDFA) and posterior proximal tibial angle (PPTA) were measured by using lateral X-ray films at 3 months after operation that were used to evaluate the sagittal position of the prosthesis.ResultsThere was no significant difference in operation time between the two groups (t=?1.128, P=0.262). One case of posterior tibial artery thrombosis occurred in the dominant group, and 1 case of poor healing of the incision occurred in each of the dominant group and the non-dominant group. Patients in both groups were followed up 12-34 months with an average of 22.0 months. The HSS scores at last follow-up were 87.2±4.3 in the dominant group and 86.8±5.0 in the non-dominant group. There was no significant difference between the two groups (t=0.471, P=0.639). No complications such as periprosthetic infection, prosthetic loosening, or periprosthetic fracture occurred during follow-up. There was no significant difference in the HKA, mLDFA, and mMPTA between the two groups before and after operation (P>0.05). The differences in the incidence of sagittal femoral prosthesis malposition and PDFA between the two groups were significant (P<0.05); however, there was no significant difference in the PPTA, the rate of femoral prosthesis distributed in the neutral position, the incidence of over-flexed femoral prosthesis, and the incidence of anterior femoral notch (P>0.05).ConclusionThe surgeon’s handedness is one of the factors affecting the placement of the sagittal femoral prosthesis in primary TKA. The incidence of sagittal femoral prosthesis malposition could increase when the surgeon performs on the non-dominant side.
Objective To investigate the rotational mismatch of total kneereplacement with medial 1/3 of tibial tuberosity as bony landmark in osteoarthritic patients with varus or valgus deformity. Methods Axial images on computed tomography of 62 knees (including 55 varus deformities and 7 valgus deformities) in 32 Chinese osteoarthritic patients who had total knee arthroplasty were analyzed, compared with that of 10 healthy knees. On images of the distal femur, the angle between the lines of surgical epicondylar axis(SEA) and posterior condylar axis was measured as posterior condylar angle (PCA), and on images of the proximal tibia, a baseline for the anteriorposterior axis of each component was drawn based on the SEA for the femur and the medial 1/3 of the tibial tuberosity for the tibia. The angle between these lines (Angle α) was defined as therotational mismatch between the components when they were aligned to the anatomic landmarks of each bone. Results The sulcus of medial epicondyle of femur could be identified on CT images of over 80% osteoarthritic knees; the median value of PCA was +2.36°, with an individual variation of 0° to +7.5°. Angle α was +6.45±3.68°(range, 0° to +11.8°) in 10 healthy knees, which increased significantly to +10.85±10.47°(range, 0° to +28.1°)in 55 varus knees (P＜0.05), which also increased significantly to +11.6±7.3°(range, -6.5° to +26.8°) in 7 valgus knees (P＜ 0.05). Conclusion With the medial 1/3 of the tibial tuberosity as the rotational landmark for the tibial component, there was a tendency to align the tibial component in external rotational position relative to the femoral component in knees with normal alignment, the rotational mismatch increased in Chinese osteoarthritic knees with varus and valgus deformity.
ObjectiveTo investigate the correlation between graft maturity and knee function after anterior cruciate ligament (ACL) reconstruction.MethodsA total of 50 patients who underwent ACL reconstruction with autologous tendons between August 2016 and August 2018 were included in the study. There were 28 males and 22 females, with an average age of 31.0 years (range, 18-50 years). At 6 months and 2 years after operation, the signal to noise quotient (SNQ) values of tibial and femoral ends of graft were measured by MRI, and the mean value was taken as the SNQ value of graft. The function of knee joint was evaluated by Tegner, Lysholm, and International Knee Documentation Committee (IKDC) scores. The differences in SNQ values between tibial and femoral ends were analyzed at 6 months and 2 years after operation. The correlation between SNQ value at 6 months after operation and knee function score at 2 years after operation was analyzed. According to SNQ value at 6 months after operation, the patients were divided into group A (SNQ value≥12) and group B (SNQ value<12) and the correlation between SNQ value and knee function score was further analyzed.ResultsAll incisions healed primarily without infection or injury of blood vessels and nerves. All patients were followed up 24-28 months (mean, 26.6 months). The IKDC, Lysholm, and Tegner scores at 6 months and 2 years after operation were significantly higher than those before operation (P<0.05), and all scores at 2 years after operation were also significantly higher than those at 6 months (P<0.05). The SNQ values at 6 months and 2 years after operation were 12.517±6.272 and 10.900±6.012, respectively, and the difference was significant (t=1.838, P=0.007). The SNQ values of graft at 6 months after operation were significantly different from those at 2 years after operation (P<0.05), and the SNQ values of tibial and femoral ends of graft at the same time point were significantly different (P<0.05). The SNQ value of 50 patients at 6 months after operation was negatively correlated with Lysholm, IKDC, and Tegner scores at 2 years after operation (r=–0.965, P=0.000; r=–0.896, P=0.000; r=–0.475, P=0.003). The patients were divided into groups A and B according to the SNQ value, each with 25 cases; the SNQ values of the two groups at 6 months after operation were negatively correlated with Lysholm, IKDC, and Tegner scores at 2 years after operation (P<0.05).ConclusionAfter ACL reconstruction, the knee function scores and graft maturity of patients gradually improved. The lower the SNQ value in the early stage, the higher the knee function score in the later stage. The SNQ value of MRI in the early stage after ACL reconstruction can predict the knee function in the later stage.
Objective To compare the long-term effectiveness of patellar denervation by electrotomy combined with patellar replacement and patellar denervation by electrotomy alone in primary total knee arthroplasty (TKA). Methods A retrospective analysis was conducted on the clinical data of 30 patients treated with primary TKA of both knees between July 2013 and March 2015 who met the selection criteria. There were 11 males and 19 females, aged 56-79 years, with an average age of 67.6 years. One knee was randomly selected for patellar denervation by electrotomy combined with patellar replacement during TKA (combined group), while the other knee was treated with patellar denervation by electrotomy alone (control group). All patients adopted the same type of total knee prosthesis. After surgery, the patients were followed up regularly, and the occurrence of complications was recorded. The functions of the knee and patella were evaluated using the Knee Society Score (KSS) and Feller score, respectively. The position of the prosthesis, patella trajectory, and prosthesis loosening and wear were observed by imaging examination. Results All 30 patients were followed up 81.4-103.5 months, with an average of 90.4 months. The patellar thickness of the combined group ranged from 21 to 26 mm, with an average of 23.0 mm. The position of the prosthesis and patella trajectory in the combined group and the control group were good, without obvious loosening or wear. After operation, 2 sides (6.7%) in the combined group and 3 sides (10.0%) in the control group presented joint adhesion and poor activities. No complication such as lower limb deep vein thrombosis, aseptic fractures, and infections around the prosthesis occurred in both groups. At last follow-up, the KSS clinical score, KSS function score, and Feller score showed no significant difference between the two groups (P>0.05). According to the KSS score, 24 patients (80.0%) had no obvious preference for patellar denervation combined with patellar replacement, 3 patients (10.0%) preferred patellar replacement combined with patellar denervation, and 3 patients (10.0%) preferred no patellar replacement. Anterior knee pain occurred in 6 sides (20.0%) of both groups. Conclusion There is no significant difference in the long-term effectiveness between patellar denervation combined with patellar replacement and patellar denervation alone conducted in patients with knee osteoarthritis undergoing primary TKA.
ObjectiveTo evaluate the risk factors for postoperative indwelling catheter following enhanced recovery after primary unilateral total knee arthroplasty (TKA) under general anesthesia.MethodsPatients who underwent primary unilateral TKA under general anesthesia between January 2017 and August 2018 were enrolled in the study. Among them, 205 patients who met the selection criteria were included in the study, and the clinical data were collected, including gender, age, body mass index, preoperative range of motion, Hospital for Special Surgery (HSS) score, American Society of Anesthesiologists (ASA) score, disease type, comorbidity, hemoglobin, hematocrit, blood volume, length of operation and operation time, whether to keep drainage after surgery, intraoperative blood loss, total blood loss, and preoperative, intraoperative, postoperative fluid infusions, and total fluid infusion on the day of surgery, urine volume on the day of surgery. Univariate analysis and logistic regression analysis were used to screen the risk factors for postoperative indwelling catheter. Length of stay and incidences of complications (intermuscular vein thrombosis, deep vein thrombosis, pulmonary embolism, incision swelling and exudation, electrolyte disorder, nausea and vomiting, and urinary tract infection) were compared between the patients with or without indwelling catheter.ResultsIndwelling catheter occurred in 41 (20%) of 205 patients. Single factor analysis showed that the influence factors were age, gender, keeping drainage after surgery, total fluid infusion and urine volume on the day of surgery (P<0.05). The multiple factors analysis showed that the males and more urine volume on the day of surgery were the significant risk factors for indwelling catheter after primary TKA (P<0.05). In addition, postoperative length of stay was shorter and the incidence of urinary tract infection was lower in non-indwelling catheter group than in indwelling catheter group, showing significant differences (P<0.05).ConclusionThe male patients with more urine on the day of surgery have higher risk for indwelling catheter after primary unilateral TKA under general anesthesia with an enhanced recovery program.
Objective To determine the short-term effectiveness of matrix-induced autologous chondrocyte implantation (MACI) for femoral trochlea cartilage injury. Methods A retrospective analysis was performed on the clinical data of 10 patients with femoral trochlea cartilage injury treated with MACI between June 2012 and October 2014. There were 6 males and 4 females, aged from 15 to 48 years (mean, 33 years). The left knee was involved in 3 cases and the right knee in 7 cases. Nine patients had a history of trauma, and 1 case suffered from osteochondritis dissecans. Combined injuries included meniscus injury in 1 case, anterior cruciate ligament injury in 3 cases, and lateral collateral ligament tear in 2 cases. The mean lesion depth was 2.80 mm (range, 2-7 mm), with the mean defect size of 84.85 mm2 (range, 28.26-153.86 mm2). The mean duration of definite diagnosis was 14 days (range, 5 days to 3 months). By using arthroscopic biopsy, 200-300 mg healthy articular cartilage at non weight-bearing area of the knee femoral trochlea was collected as a source of seed cells, which were isolated and cultured to prepare MACI membrane. The adhesion activity, growth rate, and mechanical properties of the chondrocytes on the Bio-gide collagen scaffold were evaluated. In addition, the stretch rate, tensile strength, and suture strength of scaffold were tested. MACI membrane was implanted after 2 weeks to 6 months. The visual analogou scale (VAS), Lysholm score, and Tegner movement level score at preoperation and last follow-up were used to assess the function. Results The MACI membrane was successfully prepared, and the human chondrocytes adhered and grew well on the Bio-gide collagen scaffold. Mechanical test showed that MACI membrane had the stretch rate of 65.27%, the tensile strength of 26.81 MPa, and the suture strength of 6.49 N, indicating good mechanical properties. MACI membrane was successfully implanted. The mean operation time was 58.5 minutes (range, 43-99 minutes), and the mean hospitalization time was 7 days (range, 6-15 days). All incisions healed well. Ten cases were followed up 9 to 16 months (mean, 12 months). Four cases underwent iliac bone graft surgery. The mean healing time was 14 weeks (range, 12-16 weeks). No complications of osteochondrolysis, knee pain, nerve and vascular injury, deep vein thrombosis, and knee adhesion occurred during follow-up. The VAS score, Lysholm score, and Tegner score at last follow-up were significantly improved when compared with preoperative scores (t=12.060,P=0.000;t=–9.200,P=0.000;t=–14.000,P=0.000). Conclusion MACI for femoral trochlea cartilage injury has good short-term effectiveness, with less injury and fast function recovery.
Objective To investigate the feasibility and effectiveness of high tibial osteotomy (HTO) in treatment of chronic multi-ligament knee injury (MLKI) associated with lower extremity malalignment. Methods A clinical data of 14 patients (14 knees) of chronic MLKI associated with lower extremity malalignment, who were treated with HTO between January 2016 and September 2020, was retrospectively analyzed. There were 10 males and 4 females, with an average age of 30.5 years (range, 22-48 years). The causes of injury included traffic accident in 8 cases, bruising by a heavy object in 3 cases, falling from height in 2 cases, and twisting in 1 case. According to Schenck classification of knee dislocation (KD), there were 4 cases of KD-Ⅰ [2 cases of anterior cruciate ligament (ACL) and posterolateral complex (PLC) injuries and 2 cases of posterior cruciate ligament (PCL) and PLC injuries], 7 cases of KD-Ⅲ (all of ACL, PCL, and PLC injuries), and 3 cases of KD-Ⅳ. The preoperative hip-knee-ankle angle (HKA) was (167.1±4.7)°, and the posterior tibial slope angle (PTSA) was (16.3±2.7)°. The knee joint was severely unstable and the patients could not stand and walk normally. Among them, 5 cases of medial compartment cartilage were severely worn out (3 cases of Kellgren-Lawrence grading Ⅱ, 2 cases of grading Ⅲ) causing pain. After admission, 2 cases of KD-Ⅰ underwent HTO and ligament reconstruction in the first stage, 1 case of KD-Ⅲ and 1 case of KD-Ⅳ underwent HTO in the first stage and ligament reconstruction in the second stage; the remaining 10 patients only underwent HTO. Results All patients were followed up 12-50 months, with an average of 30 months. The incisions healed by first intention after operation, and no complications such as infection and deep vein thrombosis of the lower extremities occurred. At 12 months after operation, knee range of extension was –5°-0° (mean, –1.2°) and range of flexion was 110°-140° (mean, 125.5°). The Lachman test was negative in 11 cases and positive in 3 cases. The posterior drawer test was negative in 9 cases and positive in 5 cases. The 0/30° varus stress test was negative in 10 cases and positive in 4 cases. The 0/30° valgus stress test was negative in 13 cases and positive in 1 case. The visual analogue scale (VAS) score was significantly lower than that before operation (P<0.05), and the International Knee Documentation Committee (IKDC) score, Lysholm score, and Tegner score were all significantly higher than those before operation (P<0.05). The X-ray film reexamination at 12 months after operation showed that the HKA was (178.2±3.8)° and the PTSA was (8.6±2.4)°, which were significantly different from those before operation (P<0.05). All osteotomies achieved bone union, and the healing time was 3-11 months, with an average of 6.8 months. Conclusion For chronic MLKI associated with lower extremity malalignment, HTO can restore normal lower extremity alignment and improve knee joint function, which is a feasible salvage operation.
Objective To analyze the relationship between the collateral ligament attachment and the epicondylar axis with rotational alignment of the femoral component in the total knee arthroplasty(TKA).Methods Twenty normal cadaver knee joints were anatomized and 2 holes were drilled on the distal femur from the deep and superficial insertions of the medial collateral ligaments to the lateral condylar part, respectively. Then, all the knees were scanned by MRI on the sagittal plane, making the drilled hole located relatively to the posterior condylar joint surface on the axial plane, and the posterior condylar angle (PCA) and thecondylar twist angle (CTA) were measured.Results The colateral ligament had the deep and superficial parts, and the deep part was strained during the knee flexing. PCA and CTA were 4.50±1.26° and 7.10±0.30° respectively, and there was a significant difference between them(P＜0.05), which were significantly greater than those reported abroad. On the sagittal plane, there wasno significant difference between the radiuses of the posterior medial and lateral condylar circles (Pgt;0.05). The distance from the center of the posterior condylar circle to the deep insertion of the medial collateral ligament (MCL) (d1) was 4.22±0.20 mm, and the distance to the superficial insertionof MCL (d2) was 7.36±0.13 mm. The difference between d1 and d2 was significant(Plt;0.05). Conclusion The center of the posterior condylar circle passes from the deep insertion of the collateral ligament, which can be regarded as a fixed flexionextension axis of the knee. By releasing the different parts of the collateral ligaments, the balance of the flexion and extension gap canbe obtained, and then varus, valgus or flexed contracture deformity of the kneecan be realigned. Besides, the rotational orientation of the femoral prothesis can be made by a reference to the epicondylar insertion of the collateral ligament.