Could surgical transepicondylar axis be identified accurately in preoperative 3D planning for total knee arthroplasty? A reproducibility study based on 3D-CT.

BACKGROUND: Surgical transepicondylar axis (sTEA) is frequently used for positioning of femoral component rotation in total knee arthroplasty (TKA). Previous studies showed that intraoperative identification of sTEA was not reliable. While surgeons or engineers need to identify sTEA with three-dimensional (3D) computer-aid techniques pre- or intraoperatively, the reproducibility of sTEA identification on preoperative 3D images has not been explored yet. This study aimed to investigate the reproducibility of identifying sTEA in preoperative planning based on computed tomography (CT). METHODS: Fifty-nine consecutive patients (60 knees involved) who received TKA in our center from April 2019 to June 2019 were included in this study. Six experienced TKA surgeons identified sTEA three times on 3D model established on the basis of knee CT data. The projection angle of each sTEA and the posterior condyle axis on the transverse plane were measured and analyzed. RESULTS: The overall intra-observer reproducibility was moderate. The median intra-observer variation was 1.27°, with a maximum being up to 14.07°. The median inter-observer variation was 1.24°, and the maximum was 11.47°. The overall intra-class correlation coefficient (ICC) for inter-observer was 0.528 (95% CI 0.417, 0.643). CONCLUSION: The identification of sTEA on a 3D model established on the basis of knee CT data may not be reliable. Combined with the previous cadaveric and surgical studies, caution should be exercised in determining femoral component rotation by referencing sTEA both preoperatively and intraoperatively. LEVEL OF EVIDENCE: III.

Clinical value of CT-based patient-specific 3D preoperative design combined with conventional instruments in primary total knee arthroplasty: a propensity score-matched analysis.

PURPOSE: To evaluate the operation and early clinical effect in primary total knee arthroplasty (TKA) about the novel combination of CT-based patient-specific three-dimensional (3D) preoperative design and conventional osteotomy instruments, compared with the conventional method. METHODS: After a 1:1 propensity score-matching (PSM), patients were matched to the novel technique group and the conventional group, 109 cases in each group. The conventional group adopted a preoperative design based on a full-length radiograph (FLX) and received TKA with conventional osteotomy instruments. The novel technique group used a CT-based patient-specific 3D preoperative design combined with conventional osteotomy instruments; during the surgery, the femoral entry point, femoral valgus osteotomy angle, the fix point of tibial plateau extramedullary guide pin, and the position of tibial extramedullary positioning rod were accurately selected according to the preoperative 3D design to ensure accurate intraoperative implementation. The lower limb alignment, component position, operation time, tourniquet time, hospital stay, blood loss volume, incidence of postoperative complications, visual analog scale (Vas) score, and New Knee Society Score System (NEW-KSS) at 1 day before operation and 1, 6, and 12 months after operation were recorded and compared. RESULTS: The novel technique group was significantly better than the conventional group in controlling lateral tibial component angle (LTC) (P < 0.001), and the novel technique group had lower percentages of hip-knee-ankle angle (HKA) outliers (P < 0.001) and overcorrection (P = 0.003). The operation time, tourniquet time, and hospital stay of the novel technique group was shorter (P < 0.05). In 1 month after the operation, the novel technique group achieved a significantly better VAS score (P < 0.05), but a similar NEW-KSS score (P > 0.05) when compared with the conventional group. But in 6 and 12 months after surgery, no statistical differences were seen in the above two scores (P > 0.05). CONCLUSION: The novel technique of CT-based patient-specific 3D preoperative design combined with conventional instruments can improve the accuracy of osteotomy in primary total knee arthroplasty, with benefits of significantly reducing pain and rapid recovery during the early postoperative period, but having no obvious effect on outcome after a 1-year follow-up.

A study of pre-operative presence of micro-organisms in affected knee joints of rheumatoid arthritis patients who need total knee arthroplasty.

BACKGROUND: To evaluate, by way of intraoperative tissue culture and pathological study, the pre-operative presence of micro-organisms in knee joints of patients with rheumatoid arthritis (RA) who need total knee arthroplasty (TKA). METHODS: From November 2012 to January 2014, 47 patients with RA (53 knees) who needed TKA were included in this study. Patients received routine pre-operative examination and joint fluid routine and culture. Each RA patient was match-paired with one osteoarthritis (OA) patient. During arthrotomy, synovial tissue was reserved and portioned for culture, frozen section, and routine pathologic examination. RESULTS: Pre-operative infection in all knees was ruled out. There were 12 RA patients (13 knees) with positive culture results: two Escherichia coli, two Staphylococcus epidermidis, two Staphylococcus aureus, one Proteus mirabilis, one Staphylococcus warneri, one Enterococcus faecalis, one Acinetobacter baumannii, one Candida albicans, one Ochrobactrum anthropi, and one Candida glabrata. Except for microabscess found in one RA patient, all pathological sections showed mild chronic inflammation but no infection. All patients with positive culture results were administered sensitive antibiotics for six weeks after surgery. Two patients had deep infection: one had a fused knee after a failed debridement, and the second was previously treated with an amphotericin injection. CONCLUSION: Pre-operative presence of micro-organism in knee joints of RA patients is common (24.5%). This finding of a high incidence of pre-operative presence of micro-organism in joints of RA patients before arthroplasty may suggest a role of micro-organism in the pathogenesis of prosthetic joint infection (PJI). Intraoperative synovial tissue culture is valuable for diagnosis of this condition and in instruction of antibacterial treatment.

[Analysis of HPA gene Polymorphisms in Children with Acute or Chronic ITP].

OBJECTIVE: To investigate the frequency distribution of human platelet antigen allele HPA-2 and HPA-15 among the pediatric patients with acute or chronic idiopathic thrombocytopenic purpura (ITP) in Chinese Guangxi area, and to explore the potential correlation of ITP with HPA-2 and HPA-15 gene polymorphisms. METHODS: The clinical and laboratorial data of 46 children diagnosed as acute ITP and 46 children diagnosed as chronic ITP between January 2007 and December 2014 were collected. Genotyping of HPA-2 and HPA-15 in 92 ITP patients and 48 healthy controls was performed by using polymerase chain reaction (PCR) combined with direct sequencing. RESULTS: The allele frequencies of HPA-2 and HPA-15 were significantly different among the acute, chronic and control groups; the allele frequencies were significantly different between the chronic ITP group and the control group (P<0.0167), while the difference was not statistically significant between the acute and chronic ITP groups as well as between the acute ITP and the control group (P>0.0167). CONCLUSION: The gene polymorphism of HPA-2 and HPA-15 may correlate with the risk of chronic ITP, but may not correlate with acute ITP in children.

An Arthroscopic Second-Look Study on the Effect of Remnant Preservation on Synovialization of Bone-Patellar Tendon-Bone Allograft in Anterior Cruciate Ligament Reconstruction.

PURPOSE: To assess the effects of preserved more anterior cruciate ligament (ACL) remnant on synovial coverage, knee stability, and function after bone patellar-tendon-bone (BPTB) allograft reconstruction through second-look arthroscopy and follow-up study. METHODS: From June 2007 to February 2009, 51 patients received single bundle BPTB allograft ACL reconstruction and second arthroscopic examination. The patients were divided into 4 types according to the types of ACL remnant: type 1, 18 had bridging between the posterior cruciate ligament and the tibia; type 2, 21 had bridging between the intercondylar notch roof and the tibia; type 3, 4 had bridging between the lateral condyle and the tibia; and type 4, 8 subjects had no ACL remnants. Clinical results were evaluated with the KT-1000 maximum displacement test and Lysholm scale at mean 12.3- and 53.5-month follow-up. Second-look synovium coverage was recorded as follows: covering 25% or less, 25% to 50%, 50% to 75%, and more than 75%. RESULTS: Mean percentage of synovium coverage, Lysholm scale, and KT-1000 side-to-side difference were poorer in types 3 and 4 than the other 2 types at mean 12.3-month follow-up without statistical differences. The result of the final follow-up was comparable with the first one. Four patients had ruptured grafts and accepted revision surgery. Three of them belonged to types 3 and 4, and 1 patient with sport trauma belonged to type 2. There were other 11 patients with different types of impingement and partial absorption of grafts. CONCLUSIONS: Although lack of statistical power, follow-up study and second-look arthroscopy showed that preserved type 3 and 4 ACL remnant caused poorer synovium coverage and might lead to earlier failure when using BPTB allograft. Early minor laxity at 12.3-month follow-up seemed to be not progressive at the final follow-up. LEVEL OF EVIDENCE: Level III, case-control study.