Postoperative Lower Limb Alignment Research Articles

Pulsed electromagnetic fields after intramedullary nailing of tibial fractures: a case control study.

To compare clinical and functional outcomes of two groups of patients undergoing reduction and nailing fixation for diaphyseal fractures of the tibia with (PEMF group) and without (control group) post-operative pulsed electromagnetic field (PEMF) application. This is a retrospective study on 50 patients (mean age 43.3years, 28 males and 22 females) with diaphyseal tibial fractures managed between 2017 and 2019. Twenty-five patients underwent reduction, nailing fixation, and PEMF application post-operatively (PEMF group) and 25 patients underwent nailing fixation. Radiographic imaging assessment was performed every month until fracture healing had been evident. Use of analgesics, fracture healing time, post-operative lower limb alignment, and post-operative complications were recorded. Patients were asked about return to preinjury activity. All patients were assessed at 3months and at an average follow-up of 13months. The VAS scale and Johner-Wruhs criteria were used for pain assessment and functional recovery, respectively. Comparing groups, VAS values were significantly lower in the PEMF group at threemonths and comparable at oneyear. The patients in the PEMF group took an average of 4.1months to resume their preinjury activities, and control patients took an average of 5.3months (P < 0.0001). According to the Johner-Wruhs score, the effective rate was 100% (25/25) in the PEMF group and 92% (23/25) in the control group (P = 0.14). PEMF application after intramedullary nailing is safe and reduces post-operative pain, use of analgesics, and the time of healing fracture. At oneyear, there is no difference in outcome measures, regardless of PEMF application.

Periprosthetic fractures after medial unicompartmental knee arthroplasty: a narrative review.

On rare occasions, fractures of the tibial plateau may occur after uni-compartmental knee arthroplasty (UKA) and account for 2% of total UKA failures. The purpose of this narrative review is to identify and discuss potential risk factors that might lead to prevention of this invalidating complication. Electronic database of Pubmed, Scopus, Cochrane and Google Scholar were searched. A total of 457 articles related to the topic were found. Of those, 86 references were included in this narrative review. UKA implantation acts as a stress riser in the medial compartment. To avoid fractures, surgeons need to balance load and bone stock. Post-operative lower limb alignment, implant positioning, level of resection and sizing of the tibial tray have a strong influence on load distribution of the tibial bone. Pain on weight-bearing signals bone-load imbalance and acts as an indicator of bone remodeling and should be a trigger for unloading. The first three months after surgery are critical because of transient post-operative osteoporosis and local biomechanical changes. Acquired osteoporosis is a growing concern in the arthroplasty population. Split fractures require internal fixation, while subsidence fractures differ in their management depending of the amount of bone impaction. Loose implants require revision knee arthroplasty. Peri-prosthetic fracture is a rare, but troublesome event, which can lead to implant failure and revision surgery. Better knowledge of the multifactorial risk factors in association with a thorough surgical technique is key for prevention.

Influence of hindfoot alignment on postoperative lower limb alignment in medial opening wedge high tibial osteotomy.

We have experienced unexpected under-correction after medial opening wedge high tibial osteotomy (MOWHTO). Although the tibia was corrected accurately, the postoperative mechanical axis (MA) was less than 57%. The purpose of this study was to evaluate the relationship between hindfoot alignment and postoperative lower limb alignment, and to reveal whether hindfoot alignment affects lower limb alignment after MOWHTO. Our hypothesis was that hindfoot alignment influences the postoperative MA in MOWHTO. This study was a retrospective comparative study. The study cohort comprised 43 knees in 43 patients who underwent MOWHTO and had standing long-leg anteroposterior view and hindfoot alignment view radiographs taken preoperatively and at 3months postoperatively. To evaluate the hindfoot alignment, the absolute value of the ankle joint line orientation relative to the ground was added to the absolute value of the hindfoot angle. We defined a postoperative MA of 57-67% as acceptable correction (A group) and a MA of < 56% as under-correction (U group). The two groups were analyzed to identify factors that affected postoperative limb alignment. The preoperative hindfoot alignment angle was significantly larger in the U group than the A group. The preoperative hindfoot alignment angle was a significant predictive factor of the postoperative MA, and the cut-off value that distinguished under-correction from acceptable correction was 15.9 degrees. Abnormal hindfoot alignment is one of the causes of under-correction after MOWHTO. Attention should be paid to the preoperative ankle joint line orientation relative to the ground and hindfoot angle. If the preoperative hindfoot alignment angle is ≥ 15.9 degrees, surgeons should reconsider the operative procedure and correction angle. Therapeutic level III, retrospective study.

Contralateral Lower-Limb Functional Status Before Total Hip Arthroplasty: An Important Indicator for Postoperative Gait Speed.

Postoperative gait speed, especially comfortable gait speed, is an important factor for predicting function after total hip arthroplasty (THA). In this study, we examined factors related to gait speed, including preoperative lower and upper-limb functional parameters and postoperative lower-limb alignment. In addition, we examined factors related to postoperative good comfortable gait speed (≥1.34 m/s: one indicator of a good clinical outcome). The purpose of this study was to determine if better preoperative functional parameters had a positive effect on postoperative gait speed. This prospective case-control study included 91 patients with hip osteoarthritis who underwent unilateral THA. Patients who had undergone a prior hip surgical procedure or had Crowe type-3 and 4 hips, complications after THA, knee osteoarthritis-related pain, and severe lumbar conditions were excluded. The 1-leg standing time (OLST) and knee extensor strength of the operatively treated side and the contralateral side and the functional reach test were examined preoperatively and at 1 year postoperatively. The leg-length discrepancy and global offset compared with the contralateral side and leg lengthening were examined using 3-dimensional models captured through computed tomographic scans. The preoperative contralateral side OLST was a significant factor (p < 0.001) for postoperative comfortable gait speed, and the preoperative contralateral-side knee extensor strength was a significant factor (p = 0.018) for postoperative maximum gait speed. Leg-length discrepancy and differences in global offset after THA were not significant factors for postoperative gait speed. The preoperative comfortable gait speed with a cutoff value of 1.115 m/s (area under the receiver operating characteristic curve, 0.690 [95% confidence interval, 0.569 to 0.810]; p = 0.003; sensitivity of 65.5% and specificity of 74.2%) was an independent factor associated with a good postoperative comfortable gait speed. Preoperative contralateral-side OLST was a significant factor (p = 0.027) for preoperative comfortable gait speed. The preoperative contralateral-side, lower-limb functional status is a significant factor for postoperative gait speed. Early surgical intervention before the contralateral-side function declines or a preoperative rehabilitation intervention on the contralateral side may improve THA outcome. Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Mechanical Alignment in Knee Replacement Homogenizes Postoperative Coronal Hip-Knee-Ankle Angle in Varus Knees: A Navigation-Based Study.

After knee replacement, postoperative lower limb alignment is influenced by the geometry of the prosthesis position and surrounding soft tissue that contributes to the hip-knee-ankle (HKA) angle. The purpose of this study is to determine the dynamic coronal HKA angle after mechanical alignment in total knee replacement using computer navigation. We conducted a pre-post design study of 71 patients with varus osteoarthritic knees on which total knee arthroplasty was performed. The HKA was measured before and at the end of the surgical procedure with the patient in the supine position using a navigation system at 30, 60, and 90 degrees of knee flexion. Postoperative implant position and flexion and extension gaps were assessed. HKA was clustered in three preoperative dynamic patterns (PDPs; Varus-Neutral, Varus-Valgus, and Varus-Varus). There were statistically significant differences in the dynamic coronal HKA between the preoperative and postoperative statuses after mechanically aligned knee replacement (with p < 0.0001) Before the surgical procedure, statistically significant differences were found between patterns at any angle of flexion confirming a well-differentiated preoperative dynamic behavior between the three groups. Postoperatively, 98.6% (71 out of 72) of the knees were within ± 3 degrees of the HKA at full extension. Fifty-eight knees (80.6%) were assessed to a "within-range" postoperative dynamic alignment at any grade of flexion considered. There are differences between the preoperative and postoperative status of the dynamic coronal HKA angle after mechanically aligned knee replacement. We proposed that an excellent dynamic HKA alignment is achieved not only at full extension within the range of 0 ± 3 degrees but also when this alignment is maintained at 30, 60, and 90 degrees.

Valgus Correctability and Meniscal Extrusion Were Associated With Alignment After Unicompartmental Knee Arthroplasty.

Appropriate postoperative lower limb alignment is one important element of a successful unicompartmental knee arthroplasty (UKA). To predict postoperative alignment, it is important to investigate the association between preoperative imaging evaluations and lower limb alignment after medial UKA. (1) Do preoperative valgus stress radiographic and MRI measurements (% mechanical axis, hip-knee-ankle angle, medial meniscal extrusion distance, and osteophyte area at the medial femur and tibia) correlate with postoperative lower limb alignment after UKA; and (2) Can useful cutoffs be calculated in advance of surgery for those findings that were associated with coronal-plane overcorrection? We retrospectively analyzed 125 patients with medial knee pain who underwent UKA from January 2012 to October 2018. Valgus stress radiography and MRI were performed routinely to assess the knee. Valgus stress radiography was obtained with the patient supine with the knee in full extension and a firm manual valgus force applied to the knee. Full-length weightbearing radiography was performed 3 months after surgery. There were 12% (15) of patients who did not undergo MRI, and 4% (five) of patients who did not receive the postoperative full-length weightbearing radiograph and they were excluded, leaving 84% (105) of patients available for analysis. There were 27 men and 78 women with a mean (range) age of 77 years ± 6 years (60 to 87). The preoperative diagnosis was medial osteoarthritis in 99 patients and osteonecrosis of the medial femoral condyle in six. To investigate the associations, we routinely measured % mechanical axis using radiography, and also measured the medial meniscal extrusion distance and osteophyte area at the medial femur and tibia using MRI after surgery. Medial meniscus extrusion distance was defined as the distance from the outermost edge of the medial meniscus to a line connecting the femoral and tibial cortices. From these parameters, postoperative alignment was estimated using regression and receiver operating characteristic curve analyses. Variables with p < 0.05 were included. The % mechanical axis on the valgus stress radiograph and medial meniscal extrusion distance were correlated with postoperative lower limb alignment after UKA (adjusted correlation coefficient 0.72; p < 0.001, adjusted correlation coefficient 0.2; p = 0.003, respectively). The estimated % mechanical axis on the postoperative weightbearing radiograph was equal to -0.27 + 0.86% (% mechanical axis on valgus stress radiograph) + 1.14 mm (medial meniscal extrusion distance). Using a cutoff point of 36%, the % mechanical axis on valgus stress radiograph was associated with overcorrection after UKA (area under the curve: 0.89; odds ratio 14 [95% CI 0.75 to 0.95]; p < 0.001, sensitivity 77.8%, specificity 80.9%). The overcorrection of a varus knee on a valgus stress radiograph before UKA and the increased extrusion of the medial meniscus on preoperative MRI was associated with a greater likelihood of overcorrected alignment after UKA. Future studies should conduct long-term follow-up of malalignment patients to assess the possible complications. Level III, diagnostic study.

Total Knee Arthroplasty in Patients With Extra-Articular Deformity: Restoration of Mechanical Alignment Using Accelerometer-Based Navigation System

BackgroundTotal knee arthroplasty (TKA) in patients with post-traumatic extra-articular deformity (EAD) is difficult to manage using conventional instrumentation techniques. In this study, we evaluate whether accelerometer navigation system can be a valuable option to make accurate bone resections and restore the neutral mechanical axis in complex TKA patients with EAD. MethodsFrom May 2015 to June 2017, 18 consecutive TKA were performed in 18 patients with knee osteoarthritis with associated EAD. An accelerometer-based navigation system was used to guide tibial and femoral resection in the coronal and sagittal plane. Postoperative lower limb alignment in coronal plane and component position in coronal and sagittal plane was measured through full-leg weight-bearing X-ray. Clinical score were recorded using the Knee Society Score at the final follow-up. ResultsThe mean hip-knee-ankle angle was 0.9° ± 1.4° varus alignment. The coronal alignment of the femoral component was 89.2° ± 1.9°, and the coronal alignment of the tibial component was 89.4° ± 2.1°. The sagittal alignment of the femoral component was 93.2°± 1.9°, and the sagittal alignment of the tibial component was 84.4° ± 3.1°. At the final follow-up, the Knee Society Score was 89 points (range, 82-100), and the functional score was 86.7 points (range, 60-100). No intraoperative and postoperative surgical complications were reported using this technology. ConclusionAccelerometer-based navigation is accurate in achieving neutral mechanical alignment and optimal implant position after TKA in patients with EAD. This system should be considered a valuable option to the more complex technique of computer navigation or robotic surgery.

MRI-detected osteophyte is a predictor for receiving total knee arthroplasty in patients with end-stage knee osteoarthritis

in 84 knees and rheumatoid arthritis in 6 knees. The pre-operative mechanical alignment of the lower limbwas in 13.4 6.3 (0-30) varus. The knees were randomized in 1:1:1 ratio into one of the three groups conventional instruments (CON), computer navigation (NAV) and patient specific instruments (PSI). They were also randomized with regard to the 3 surgeons. Each surgeon performed 10 CON, 10 NAV and 10 PSI TKA. The three groups were matched, except there were more male patients in the PSI group. The prostheses and surgical routines were standardized. Post-operative standing long films of the entire lower limbs were taken.We recorded the tourniquet time and the operative time (skin-to-skin). We measured the femoral and tibial component positions in the coronal and axial planes and the overall lower limb alignment of the lower limb after TKA. Results: The mean tourniquet times were 49.2 12.7 minutes for CON, 68.6 14.8 minutes for NAV and 49.1 15.3 minutes for PSI groups (p < 0.001, Oneway ANOVA). Conventional instrument was more likely to result in an excessively flexed femoral component (p 1⁄4 0.001, Oneway ANOVA). Number of outliers in postoperative lower limb alignment, and other components positions in the coronal and sagittal plane showed no statistically significant difference. Conclusion: We found that the tourniquet time and operation time of using patient specific instrument in TKA were similar to that of conventional instrument, and shorten than computer navigation. The postoperative lower limb alignment and individual component positions were similar in all 3 groups except in sagittal plane where conventional instrument resulted in a significantly flexed femoral component. Although statistical significance was not achieved, the incidence of outliers was the highest in the conventional instrument group, followed by patient specific instrument and finally computer navigation. The current studied identifiedmarginal benefit of PSI in isolated component position compared to conventional instrument. A prospective study with a larger sample size and better post-op imaging modality (e.g. CT or MRI) may be needed to prove the efficacy of PSI. 860 MRI-DETECTED OSTEOPHYTE IS A PREDICTOR FOR RECEIVING TOTAL KNEE ARTHROPLASTY IN PATIENTS WITH END-STAGE KNEE OSTEOARTHRITIS L. Liu y,z, H. Kaneko y, R. Sadatsuki y, S. Hada y, A. Yusup y, M. Kinoshita y, I. Futami y, Y. Shimura x, H. Kurosawa x, Y. Saita y, Y. Takazawa y, H. Ikeda y, K. Kaneko y,z, M. Ishijima y,z. yDept. of Med. for Orthopaedics and Motor Organ, Juntendo Univ. Graduate Sch. of Med., Tokyo, Japan; z Sportology Ctr., Juntendo Univ. Graduate Sch. of Med., Tokyo, Japan; xDept. of Orthopaedic Surgery, Juntendo Tokyo Metropolitan Koto Geriatric Med. Ctr., Tokyo, Japan

Differences in Measurement of Lower Limb Alignment Among Different Registration Methods of Navigation and Radiographs in TKA Using the OrthoPilot System

The purposes of this study were (1) to compare lower limb alignment measurements between radiographs and computer-assisted surgery and (2) to evaluate the discrepancy in lower limb alignment between computer-assisted surgery with a high tibial osteotomy protocol and computer-assisted surgery with a total knee arthroplasty (TKA) protocol in the same knee. Seventy-one TKAs were performed on patients with primary osteoarthritis using computer-assisted surgery. Preoperative lower limb alignment was measured using the mechanical axis during bipedal, weight-bearing, whole-leg anteroposterior radiography (measure 1). The intraoperative mechanical axis was measured with computer-assisted surgery according to the high tibial osteotomy protocol before joint exposure (measure 2). After changing the software and joint exposure, the intraoperative mechanical axis was measured with computer-assisted surgery according to TKA protocol (measure 3). After final TKA implantation, the lower limb mechanical axis was measured with computer-assisted surgery following the TKA protocol (measure 4). Postoperative lower limb alignment was measured using the mechanical axis on whole-leg standing anteroposterior radiographs (measure 5). The mechanical axis and median value from each group were compared. Factors affecting the mechanical axis measurement were also analyzed. The difference in the mechanical axis between measures 1 and 2, measures 1 and 3, and measures 2 and 3 was significant (P<.0001, <.0001, and =.0007, respectively). The difference between measures 4 and 5 was also significant (P<.0001). Factors affecting the mechanical axis measurement, such as age, height, weight, and range of motion, showed no correlation (R(2)=.07244 and adjusted R(2)=.01622). The pre- and postoperative radiological measurements of limb alignment using the mechanical axis were different from the intraoperative measurements with navigation.

Total knee arthroplasty coincident with high tibial osteotomy

Established lower limb alignment and knee stability are the two main prognosis factors influencing good functional result and prosthesis life. During Total Knee Arthroplasty (TKA), correction of tibial extra-articular deformity cannot be achieved without ligament balancing. Excessive valgus deformity after a failed high tibial osteotomy (HTO) necessitates a much larger resection of bone from the medial tibial plateau resulting in a trapezoidal extension gap. In overcorrected valgus knee patients after failed HTO, meticulous preoperative planning is required to predict complementary procedures needed to achieve flexion-extension balance with optimal postoperative lower limb alignment. This article details the preoperative planning involved and the intraoperative technique used in such cases. We describe a planning methodology consisting of measuring medial and lateral distance between future femoral and tibial orthogonal resection lines, drawn on valgus and varus stress radiographs (arrows). If the medial distance (medial arrows) on the valgus stress radiographs is longer than the lateral arrows on the varus stress radiographs, a lateral release will be necessary to achieve a rectangular extension gap during TKA procedure. However, the lateral release needed to compensate medial bone resection is limited. This limit must not exceed 10 millimeters (about 8 to 10° of valgus malunion). Over this limit, total knee arthroplasty plus corrective tibial osteotomy is one of the solutions. We prefer to insert prosthesis inside the “ligament box”; without any ligamentous release. The limb alignment is achieved with corrective tibial osteotomy. We propose and describe how to carry out TKA based on a rectangular extension gap, associated, in the same procedure, with a HTO to restore a neutral alignment of the leg.