Comparison of the outcomes of navigation-assisted revision of unicompartmental knee arthroplasty to total knee arthroplasty versus navigation-assisted primary TKA.

PURPOSE: Revision of unicompartmental knee arthroplasty (UKA) to total knee arthroplasty (TKA) is technically demanding but can be performed with computer navigation system guidance. The purpose of this study was (1) to compare the outcomes of revision of UKA to TKA to those of primary TKA and (2) to describe a surgical technique for the revision of UKA to TKA using a navigation system. METHODS: From May 2011 to April 2014, a total of 298 knees underwent primary navigation-assisted TKA (group 1), and navigation-assisted UKA revision to TKA was performed in 15 patients (group 2). One to three propensity score matching was performed to compare the two groups after a minimum of three years of follow-up. Radiographic and clinical outcomes in addition to radiolucent lines were evaluated during follow-up. RESULTS: In group 1, there was one case that required metal block augmentation with the long stem under the tibial plate due to severe bone loss, while in other cases, short stems were used, and cement and autogenous bone grafts were used to fill bone defects due to minimal bone loss. Pre- and post-operative outcomes were significantly improved in both groups (p < 0.001). There were no statistical differences between groups in pre- and post-operative outcomes except post-operative Knee Society Function Score (KSFS) (p = 0.008). There were no radiolucent lines in the tibia or femur in either group during follow-up. CONCLUSIONS: With the use of an appropriate surgical technique, navigation-assisted revision of UKA to TKA can yield clinical and radiologic outcomes comparable to those of primary navigation-assisted TKA. LEVEL OF EVIDENCE: Level IV.

No influence of femoral component rotation by the lateral femoral posterior condylar cartilage remnant technique on clinical outcomes in navigation-assisted TKA.

PURPOSE: To investigate whether cartilage thickness in the lateral femoral posterior condyle affects the femoral rotation angles on navigation and clinical outcomes of navigation-assisted total knee arthroplasty (TKA). METHODS: This is a prospective randomized study of navigation-assisted TKA. Fifty cases underwent TKA without removal of the lateral posterior femoral cartilage (Group 1), and 56 cases underwent TKA with removal of the lateral posterior femoral cartilage (Group 2). The femoral rotation was evaluated using CT and compared with navigation values. The angle between the clinical transepicondylar axis and posterior condylar axis measured on CT was defined as the femoral rotation angle on CT. Elevation of the joint line and patellar measurements were also evaluated. RESULTS: The clinical outcomes were not statistically different in the two groups. The radiographic measurements were not statistically different except femoral rotation angle on navigation. The mean femoral rotation angle of navigation was 4.0° ± 2.2° without cartilage removal and 5.1° ± 2.5° with cartilage removal. The reliability and validity were high between the femoral rotation angle on navigation in the cartilage removal group and that on CT, but there were no differences in clinical outcomes between the two groups. CONCLUSION: There was little effect of navigation-assisted TKA on radiographic and clinical outcomes, although femoral rotational differences were caused by the lateral femoral posterior condylar cartilage. Although the rotational differences due to cartilage would be within the clinical safety margin, surgeons should consider that difference during TKA. LEVEL OF EVIDENCE: Lower quality randomized trial (no masking), Level II.

Comparison of double-bundle anterior cruciate ligament (ACL) reconstruction and single-bundle reconstruction with remnant pull-out suture.

PURPOSE: The purpose of this study was to evaluate the stability and functional outcomes of anterior cruciate ligament (ACL) reconstruction by tensioning of the ACL remnant using pull-out sutures compared with ACL double-bundle reconstruction. METHODS: Forty-four patients were included in single-bundle reconstruction with remnant tensioning group (Group 1), and 56 patients were included in the double-bundle reconstruction group (Group 2). The remnant tissue was tensioned to the direction of posterolateral bundle, which unrelated to the type of remnant bundle. Objective knee stability was evaluated by anterior stress radiography, KT-1000 and lateral pivot shift tests. The Tegner activity scale, International Knee Documentation Committee and OrthopädischeArbeitsgruppeKnie scoring systems were used for clinical evaluation. RESULTS: No statistically significant intergroup differences were observed in mechanical stability and clinical results (n.s). However, surgical time of remnant tensioning group is shorter than double-bundle reconstruction group (P = 0.005). CONCLUSION: Remnant tensioning suture with single-bundle reconstruction could be used with positive results as good as double-bundle technique if a good ACL remnant was found bridging the femur and tibia, rather than debride or damage to the remnant tissue during operation. LEVEL OF EVIDENCE: Retrospective, comparative cohort study, Level IV.

Which orally administered antithrombotic agent is most effective for preventing venous thromboembolism after total knee arthroplasty? A propensity score-matching analysis.

PURPOSE: Even today, total knee arthroplasty (TKA) is associated with venous thromboembolism (VTE). The purpose of our study is to report the incidence of postoperative VTE and to compare the efficacy of commonly used orally administered antithrombotic agents. MATERIALS AND METHODS: Seven hundred ad ninety-nine patients who underwent primary TKA were retrospectively reviewed. The patients were prescribed one of three antithrombotic agents: aspirin (n = 168), rivaroxaban (n = 117), or apixaban (n = 514). Before surgery, patient demographics and risk factors were matched via propensity scoring. After surgery, all three groups took the agent for 7 days and underwent ultrasonography to check for VTE. RESULTS: The overall incidence of postoperative VTE was 15.4% (123/799). Only one patient developed symptomatic VTE. Female sex and staged bilateral TKA were risk factors for postoperative VTE. The postoperative VTE rates in the aspirin, rivaroxaban, and apixaban groups were 16.2%, 6.0%, and 17.1%, respectively, significantly lower in the rivaroxaban group (p <  0.02). The majority of VTEs in all three groups were calf-vein thromboses. CONCLUSIONS: All agents showed enough efficacy as antithrombotic agents. Considering that aspirin is inexpensive, aspirin is a cost-effective option for preventing postoperative VTE.

Use of the Bridge Plate Technique for the Treatment of Hamatometacarpal Fracture-Dislocations.

Background: This study aimed to describe a novel surgical technique in which a bridge plate was used for the treatment of hamatometacarpal fracture-dislocations and to assess its radiologic and clinical outcomes. Methods: A retrospective review of 16 patients treated with the bridge plate technique for hamatometacarpal fracture-dislocations was performed between 2010 and 2015. Clinical and radiographic evaluations were performed at months 3, 6, and 12 postoperatively. Active wrist and metacarpophalangeal joint ranges of motion and Quick Disabilities of Arm, Shoulder, and Hand (DASH) scores were recorded for the injured hands. Grip strength data were collected for both the injured hands and the contralateral uninjured hands. Results: All patients included in our study were male (mean age 31 years). The average Quick DASH score was 24.3 ± 9.1 at 3 months, 12.3 ± 7.3 at 6 months, and 6.2 ± 6.6 at 12 months. All patients returned to their original jobs within 5 weeks of the procedure. Grip strength eventually recovered to 90% of that of the uninjured hand, and none of the patients complained of finger or wrist joint stiffness. Conclusions: The use of the bridge plate technique may be an effective alternative treatment for patients with comminuted hamatometacarpal fracture-dislocations.

Reliability and Validity of the Femorotibial Mechanical Axis Angle in Primary Total Knee Arthroplasty: Navigation versus Weight Bearing or Supine Whole Leg Radiographs.

PURPOSE: To evaluate the reliability and validity of the femorotibial mechanical axis angle from radiographs in the weight bearing (WB) and supine positions compared with navigation-measured values. MATERIALS AND METHODS: Sixty-eight cases of navigation-assisted total knee arthroplasty (TKA) were included. The pre- and postoperative whole leg radiographs (WLRs) in WB and supine positions were compared with the initial and final navigation values. RESULTS: The mean mechanical axis angle from the preoperative WBWLR and navigation were not statistically different (p=0.079) and were correlated strongly with each other (intraclass correlation [ICC], 0.818). However, on postoperative measurements, although the WBWLR and navigation values were not different (p=0.098), they were not correlated with each other (ICC, 0.093). The standard error of measurement was 1.8°±3.6° for the preoperative WBWLR and 2.5°±4.8° for the postoperative WBWLR. The validity that was determined by the Bland-Altman plot was not acceptable for both pre- and postoperative measurements. CONCLUSIONS: The preoperative WBWLR could provide accurate but not precise measurement value of the femorotibial mechanical axis angle for navigation-assisted TKA, and postoperative measurements in navigation were not comparable with radiographic measurements. The lack of agreement was found between the radiographic and navigation measurements of the coronal alignment regardless of pre- or postoperative evaluation although the accuracy was found acceptable. LEVEL OF EVIDENCE: Level 4.

Time-dependent clinical results of rotating-platform total knee arthroplasty according to mechanical axis deviation.

PURPOSE: We hypothesized that the low contact stress (LCS) posterior stabilization system in knees with ≤3° deviation of coronal alignment would provide more favorable clinical outcomes and survival rate over the course of time. MATERIALS AND METHODS: A retrospective study was performed on 253 consecutive cases of primary total knee arthroplasty (TKA). Patients were classified according to the degree of deviation of coronal alignment on the initial postoperative radiograph as Group 1 (≤3° deviation) and Group 2 (>3° deviation). The clinical assessments were performed using the Knee Society score and Hospital for Special Surgery systems and Western Ontario and McMaster Universities index. RESULTS: The survival rate was 97.4% in Group 1 and 96.8% in Group 2. No statistically significant intergroup difference was observed in the clinical scores before surgery and since 1 year after surgery (p>0.05). However, a significant intergroup difference was noted between 6 months to 1 year after surgery (p<0.001). Less than 2 mm radiolucent lines were found more frequently in Group 2. Time-dependent improvement was noted within one year after TKA in both groups. CONCLUSIONS: Most of the expected improvements were achieved at 6 months after surgery in Group 1 and at 1 year after surgery in Group 2. The present study suggests that the LCS system yields time-dependent improvement regardless of coronal alignment deviation.