Experiences with computer navigated total knee arthroplasty.
ABSTRACT: The successful outcome of total knee arthroplasty (TKA) is very much dependent on precise positioning of the components. Inaccuracy may result in complaints as well as in early mechanical failure. Between March 2003 and September 2005, 69 TKA procedures were performed by the computer navigated technique. The postoperative outcome of this cohort was compared with the same number of TKAs done by the traditional technique. The lower limb anatomical axis was determined in all cases pre- and postoperatively by weight-bearing anteroposterior (AP) and lateral full length X-rays. The positions of femoral and tibial components were recorded. Comparing the data in the navigation group on the AP view, 96.6% of femoral and 96.9% of tibial components and on the lateral view in 95.4% of femoral and in 95.4% of tibial components, the overall postoperative axis in 95.4% fell in the range considered in the literature as optimal. In the traditional group on the AP view, 75.7% of femoral and 68.1% of tibial components and on the lateral view 81.8% of femoral and 63.6% of tibial components, the overall postoperative axis in 60.6% fell between the values considered optimal in the literature. It seems to be proven that the computer navigated total knee arthroplasty technique ensures positioning of components significantly more precisely compared with the traditional surgical method. Accuracy of navigation depends on the software used, on the correct detection of anatomical reference points, and on a potentially uneven thickness of the cement layer during final insertion of the components. The computer navigated technique does not substitute professional skill and experience, since it merely transmits information for the surgeon. The decision is in the hands of the doctor during the entire procedure. The real benefits of the computer navigated technique require further research and can be determined only after long-term analyses.
Project description:UNLABELLED: Postoperative alignment of the implanted prosthesis in computer-navigated TKA has been reported to be superior to that using the conventional technique. There is an assumption that use of computer navigation techniques can make an inexperienced or occasional TKA surgeon perform more like an expert TKA surgeon. To assess improved accuracy in recreation of mechanical alignment in TKA performed using computer navigation, a retrospective review of the experience of one of the authors (WPY) before and after using computer navigation was performed. We reviewed the radiographic results of 104 TKAs (52 computer navigation, 52 conventional technique) and found the accuracy of postoperative radiographic alignment of the implanted prosthesis was not improved by using computer navigation as judged by (1) overall limb alignment (case: varus 1.3 degrees ; control: varus 0.3 degrees ); (2) femoral component alignment (case: 90.3 degrees ; control: 90.3 degrees ); and (3) tibial component alignment (case: 89 degrees ; control: 90 degrees ). Significant factors that affected postoperative overall mechanical alignment in the current navigation series included severity of the preoperative deformity, amount of error in making bone cuts, and experience of the surgeon in using the computer navigation system. LEVEL OF EVIDENCE: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.
Project description:UNLABELLED: Computer-navigated and minimally invasive TKAs are emerging technologies that have distinct strengths and weaknesses. We compared duration of surgery, length of hospitalization, Knee Society scores, radiographic alignments, and complications in two unselected groups of 81 consecutive knees that underwent TKA using either a minimally invasive approach or computer navigation. The two groups were operated on by two different surgeons over differing timeframes. The mean surgical time was longer in the navigated group by 63 minutes. The Knee Society scores and lengths of hospitalization of the two groups were similar. The postoperative component alignments of the two groups were similar; the mean femoral valgus and tibial varus angles of the navigation group changed from 96 degrees and 88 degrees preoperatively to 95 degrees and 89 degrees postoperatively, respectively, and in the minimally invasive group, the mean femoral valgus angles and tibial varus angles changed from 97 degrees and 88 degrees preoperatively to 95 degrees and 89 degrees postoperatively, respectively. There were 11 major and three minor complications in the navigation group, including one revision, two femoral shaft fractures, four reoperations for knee stiffness, and four instances of bleeding from tracker sites. We believe the higher incidence of complications in addition to the longer operative time in the navigated group may outweigh any potential radiographic benefits. LEVEL OF EVIDENCE: Level II, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.
Project description:Background:The use of navigation for total knee arthroplasty (TKA) improves limb alignment in the coronal and sagittal planes. However, similar improvements in femoral and tibial component rotation have not yet been realized using currently available systems. Methods:We developed a modified navigated TKA technique in which femoral rotation was set using the resected tibial plane as the reference with the aim of achieving a rectangular flexion gap. Limb alignment was assessed in a cohort of 30 knees using the navigation system. Post-operative limb alignment was measured using long-leg standing radiographs. Computed tomography was used to determine post-operative component orientation. Results:Sagittal alignment data improved from a mean of 7.8° varus (pre-operative) to 0.0° (post-operative), assessed by intra-operative navigation. Post-operative hip-knee-ankle axis alignment was 0.9° valgus (mean; standard deviation [SD] 1.7°). Mean femoral component rotation was 0.5° internally rotated (SD 2.6°), relative to the surgical transepicondylar axis. Mean tibial component rotation was 0.9° externally rotated (SD 5.5°). No soft tissue releases were performed. Conclusions:These results confirm that the desired femoral rotation, set using a tibia-first approach with the resected tibial plane as the reference, can be achieved without compromising overall limb alignment. Femoral component rotation was within a narrow range, with a moderate improvement in achieving more consistent tibial component rotation compared with other techniques. This technique may prove to be useful for surgeons wishing to employ a tibia-first philosophy for TKA while maximizing the benefits associated with computer-assisted navigation.
Project description:Combined cup and stem anteversion in THA based on femoral anteversion has been suggested as a method to compensate for abnormal femoral anteversion. We investigated the combined anteversion technique using computer navigation. In 47 THAs, the surgeon first estimated the femoral broach anteversion and validated the position by computer navigation. The broach was then measured with navigation. The navigation screen was blocked while the surgeon estimated the anteversion of the broach. This provided two estimates of stem anteversion. The navigated stem anteversion was validated by postoperative CT scans. All cups were implanted using navigation alone. We determined precision (the reproducibility) and bias (how close the average test number is to the true value) of the stem position. Comparing the surgeon estimate to navigation anteversion, the precision of the surgeon was 16.8 degrees and bias was 0.2 degrees ; comparing the navigation of the stem to postoperative CT anteversion, the precision was 4.8 degrees and bias was 0.2 degrees , meaning navigation is accurate. Combined anteversion by postoperative CT scan was 37.6 degrees +/- 7 degrees (standard deviation) (range, 19 degrees -50 degrees ). The combined anteversion with computer navigation was within the safe zone of 25 degrees to 50 degrees for 45 of 47 (96%) hips. Femoral stem anteversion had a wide variability.Level II, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.
Project description:<h4>Purpose</h4>The aim of this study is to investigate the prognostic value of tibial component coverage (over-hang and under-hang) and the alignment of total knee arthroplasty (TKA) components 1?week after surgery. We select patient-reported outcome measures (PROMS) (the Knee Society score (KSS score) and the Western Ontario and McMaster Universities Osteoarthritis Index-pain score (WOMAC pain score)) and tibial bone resorption (TBR) 2?years after surgery as the end points.<h4>Methods</h4>The study retrospectively analyzed 109 patients undergoing TKA (fixed-bearing prosthesis with asymmetrical tibial tray) from January 2014 to December 2017 in Huashan Hospital. By using standard long-leg X-rays, anteroposterior (AP) and lateral X-rays of the knee, tibial component coverage (under-hang or over-hang), AP tibial-femoral anatomical angle (AP-TFA), AP femoral angle (AP-FA), AP tibial angle (AP-TA), and lateral tibial angle (L-TA) were measured at 1?week after surgery, while TBR was measured through postoperative 1-week and 2-year AP and lateral radiographs of the knee on three sides (medial side, lateral side on AP radiograph, and anterior side on lateral radiograph). The Pearson correlation analysis, simple linear regression, multiple linear regression, the Student's t test, and one-way ANOVA together with Tukey's post hoc test (or Games-Howell post hoc test) were used in the analyses.<h4>Results</h4>Tibial under-hang was more likely to appear in our patients following TKA (42%, medially, 39%, laterally, and 25%, anteriorly). In multivariate linear regression analysis of TBR, tibial under-hang (negative value) 1?week after surgery was positively correlated with TBR 2?years later on the medial (p = 0.003) and lateral (p = 0.026) side. Tibial over-hang (positive value) 1?week after surgery on the medial side was found negatively related with KSS score (p = 0.004) and positively related with WOMAC pain score (p = 0.036) 2?years later in multivariate linear regression analysis of PROMS. Both scores were better in the anatomically sized group than in the mild over-hang group (or severe over-hang) (p < 0.001). However, no significant relationship was found between the alignment of TKA components at 1?week after surgery and the end points (TBR and PROMS) 2?years later.<h4>Conclusion</h4>Under-hang of the tibial component on both the medial and lateral sides can increase the risk of TBR 2?years later. Over-hang of tibial component on the medial side decreases the PROMS (KSS score and WOMAC pain score) 2?years later. An appropriate size of tibial component during TKA is extremely important for patient's prognosis, while the alignment of components might not be as important.
Project description:<h4>Background</h4>When using the gap-balancing technique for TKA, excessive medial release and varus proximal tibial resection can be associated with internal rotation of the femoral component. Previous studies have evaluated the causes of femoral component rotational alignment with a separate factor analysis using unadjusted statistical methods, which might result in treatment effects being attributed to confounding variables.<h4>Questions/purposes</h4>(1) What pre- and intraoperative factors are associated with internal rotation of the femoral component in TKA using the gap balancing technique? (2) To what degree does femoral component rotation as defined by the navigation system differ from rotation as measured by postoperative CT?<h4>Methods</h4>Three hundred seventy-seven knees that underwent computer-assisted primary TKA attributable to degenerative osteoarthritis with varus or mild valgus alignment in which medial soft tissue release was performed, and those with preoperative radiographs including preoperative CT between October 2007 and June 2014 were included in the study. To achieve a balanced mediolateral gap, the structures released during each medial release step were as follows: Step 1, deep medial collateral ligament (MCL); Step 2, superficial MCL (proximal, above the pes anserine tendon) and semimembranosus tendon; and Step 3, the superficial MCL (distal, below the pes anserine tendon). Knees with internal rotation of the femoral component, which was directed by navigation, to achieve a rectangular mediolateral flexion gap were considered cases, and knees without internally rotated femoral components were considered controls. Univariable analysis of the variables (age, sex, BMI, operated side, preoperative hip-knee-ankle angle, preoperative medial proximal tibial angle, preoperative rotation degree of the clinical transepicondylar axis [TEA] relative to the posterior condylar axis [PCA], coronal angle of resected tibia, resection of the posterior cruciate ligament, type of prosthesis, and extent of medial release) of cases and controls was performed, followed by a multivariable logistic regression analysis on those factors where p equals 0.15 or less. For an evaluation of navigation error, 88 knees that underwent postoperative CT were analyzed. Postoperative CT scans were obtained for patients with unexplained pain or stiffness after the operations. Using the paired t-test and Pearson's correlation analysis, the postoperative TEA-PCA measured with postoperative CT was compared with theoretical TEA-PCA, which was calculated with preoperative TEA-PCA and actual femoral component rotation checked by the navigation system.<h4>Results</h4>After controlling for a relevant confounding variable such as postoperative hip-knee-ankle angle, we found that the extent of medial release (Step 1 as reference; Step 2: odds ratio [OR], 5.7, [95% CI, 2.2-15]; Step 3: OR, 22, [95% CI, 7.8-62], p < 0.001) was the only factor we identified that was associated with internal rotation of the femoral component. With the numbers available, we found no difference between the mean theoretical postoperative TEA-PCA and the postoperative TEA-PCA measured using postoperative CT (4.8° ± 2.7º versus 5.0° ± 2.3º; mean difference, 0.2° ± 1.5º; p = 0.160).<h4>Conclusions</h4>Extent of medial release was the only factor we identified that was associated with internal rotation of the femoral component in gap-balancing TKA. To avoid internal rotation of the femoral component, we recommend a carefully subdivided medial-releasing technique, especially for the superficial MCL because once the superficial MCL has been completely released it cannot easily be restored.<h4>Level of evidence</h4>Level III, therapeutic study.
Project description:<h4>Background</h4>Computer-assisted surgery (CAS) has been developed to enhance prosthetic alignment during primary TKAs. Imageless CAS improves coronal and sagittal alignment compared with conventional TKA. However, the effect of imageless CAS on rotational alignment remains unclear.<h4>Questions/purposes</h4>We conducted a systematic and qualitative review of the current literature regarding the effectiveness of imageless CAS during TKA on (1) rotational alignment of the femoral and tibial components and tibiofemoral mismatch in terms of deviation from neutral rotation, and (2) the number of femoral and tibial rotational outliers.<h4>Methods</h4>Data sources included PubMed, MEDLINE, and EMBASE. Study selection, data extraction, and methodologic quality assessment were conducted independently by two reviewers. Standardized mean difference with 95% CI was calculated for continuous variables (rotational alignment of the femoral or tibial component and tibiofemoral mismatch). To compare the number of outliers for femoral and tibial component rotation, the odds ratio and 95% CI were calculated. The literature search produced 657 potentially relevant studies, 17 of which met the inclusion criteria. One study was considered as having high methodologic quality, 15 studies had medium, and one study had low quality.<h4>Results</h4>Conflicting evidence was found for all outcome measures except for tibiofemoral mismatch. Moderate evidence was found that imageless CAS had no influence on postoperative tibiofemoral mismatch. The measurement protocol for measuring tibial rotation varied among the studies and in only one of the studies was the sample size calculation based on one of the outcome measures used in our systematic review.<h4>Conclusions</h4>More studies of high methodologic quality and with a sample size calculation based on the outcome measures will be helpful to assess whether an imageless CAS TKA improves femoral and tibial rotational alignment and tibiofemoral mismatch or decreases the number of femoral and tibial rotational outliers. To statistically analyze the results of different studies, the same measurement protocol should be used among the studies.
Project description:Although the transtibial (TT) technique for single-bundle (SB) arthroscopic anterior cruciate ligament (ACL) reconstruction has been widely used, surgeons often disadvantageously create the femoral bone tunnel at the arthroscopically noon position, which is alleged the “ACL isometric point,” when the femoral bone tunnel could be created behind the resident’s ridge with TT-SB ACL reconstruction by paying attention to the location of the tibial tunnel inlet and the angle of tibial tunnel. This alternative approach preserves ACL remnant tissue, which might contribute to better postoperative remodeling and regeneration of proprioceptive mechanoreceptors. This technique reduces surgical invasiveness and can enhance postoperative graft remodeling and proprioceptive recovery. To successfully use the devices required for this procedure, surgeons must understand the proper techniques. Hence, this technical note aims to demonstrate TT-SB ACL reconstruction with remnant tissue preservation. Technique Video Video 1 Anterior cruciate ligament (ACL) reconstruction is carried out under regional or general anesthesia without a pneumatic tourniquet. The patient is placed in a supine position with the operative knee held in the leg drop position at 90° flexion. Standard anterolateral and anteromedial portals are made. After routine arthroscopic observation, the ACL remnant tissue is pulled with a probe and confirmed to be Crain type 3. The proximal end of the remnant femoral stump located behind the resident’s ridge is minimally debrided using a shaver, and a thermal device is used to create the femoral bone tunnel. During this procedure, careful attention should be made to the ACL remnant tissue so that it is not injured and to preserve the continuity and maximize the amount of ACL remnant tissue. Anatomic insertion of the femoral anteromedial bundle (AMB) is identified behind the resident’s ridge via the anteromedial portal. Then, a longitudinal slit is made at the center of the tibial ACL remnant tissue, into which the tibial ACL guide is inserted. The center of the tibial bone tunnel is placed at the AMB footprint from the lateral to the medial tibial spine. The center of the AMB insertion is defined according to 3 surrounding landmarks, namely, the anterior ridge, lateral groove, and intertubercular fossa, and bony prominences corresponding to the ACL tibial footprint are identified. The coronal angle relative to the tibial axis averages 25.5°, and the sagittal angle relative to the tibial axis was averages 52.3°. Then, a tibial tunnel with a diameter of 8.5 to 9 mm is made. The femoral bone tunnel insert is positioned inferior to the “over-the-top” position. The 6-mm femoral aimer is inserted through the tibial tunnel to prevent posterior wall blowout with varus and internal rotation of the tibia, thus resulting in a figure-four position. Hence, the femoral bone tunnel is created lower and deeper, thus placing it behind the resident’s ridge. The 2.4-mm guide pin insertion point is confirmed via anteromedial portal considering the location behind the resident’s ridge. Then, 4.5-mm arthroscopic drilling accompanied by an 8-mm over drilling is performed to create a socket-shaped tunnel. When the femoral tunnel cannot be created behind the resident’s ridge, surgeons should consider creating a femoral tunnel using the outside-in technique or transportal technique. The length of the femoral bone tunnel is measured using a depth gage and the length of suspensory fixation device is calculated. A hamstring graft is introduced into the joint cavity through the tibial tunnel and ACL remnant tissue and then placed in the femoral socket.
Project description:The anterior cruciate ligament suture augmentation technique is a method to augment anterior cruciate ligament reconstruction (ACLR) with autologous hamstring tendons using a braided ultrahigh-molecular weight polyester or polyethylene suture or suture tape and fixed on both the femoral and tibial sides independent of the graft to act as a backup or secondary stabilizer until complete integration and ligamentization of the graft take place. The technique is proposed to allow early rehabilitation and return to sports after ACLR and may be advantageous in patients with a high body mass index and in cases with small grafts (7 or 7.5 mm in diameter). In such situations the technique is supposed to decrease the risk of reinjury, as well as the degree of postoperative lengthening or stretching of the graft, in the early postoperative avascular phase. We describe graft preparation with the internal suture augmentation technique in arthroscopic ACLR using a cortical button system on the femoral side and a Bio-Interference Screw (Arthrex, Naples, FL) on the tibial side.
Project description:Measuring acetabular anteversion is relevant to routine follow-up of total hip arthroplasties (THAs) and for malfunctioning THAs. Imageless navigation facilitates acetabular component orientation relative to the anterior pelvic plane (APP) or to the APP adjusted for sagittal pelvic tilt (PT). The optimal plain radiographic method for the postoperative assessment of anteversion is not agreed upon.(1) Do anteversion measurements on plain radiographs correlate more with APP anteversion or PT-adjusted anteversion? (2) Do measurements of anteversion performed on supine anteroposterior (AP) radiographs more accurately reflect intraoperative anteversion values for navigated THA compared to anteversion measured on cross-table lateral (CL) radiographs?Seventy patients receiving primary navigated THA were included. APP and PT-adjusted anteversion were recorded; the latter defined the intraoperative target for anteversion. Postoperative anteversion was measured on supine AP pelvis radiographs with computer software and CL radiographs with conventional methods. Intraoperative measurements were used as the reference standards for comparisons.Mean intraoperative APP anteversion was 20.6°?±?5.6°. Mean intraoperative PT-adjusted anteversion was 22.9°?±?4.5°. Mean anteversion was 22.7°?±?4.7° on AP radiographs and 27.2°?±?4.2° on CL radiographs (p?<?0.001). Only correlations between PT-adjusted anteversion and radiographic assessments of anteversion were significant. The mean difference between PT-adjusted anteversion and anteversion on AP radiographs was -0.2°?±?4.3°, while the mean difference between the PT-adjusted anteversion and anteversion measured on CL radiographs was 4.3?±?5.1° (p?<?0.001).Plain film assessment of anteversion was more accurate on supine AP radiographs than on CL radiographs, which overestimated acetabular anteversion.