Incidence of and risk factors for deep vein thrombosis in patients undergoing osteotomies around the knee: comparative analysis of different osteotomy types.

PURPOSE: To examine the incidence of and risk factors for deep vein thrombosis (DVT) among different types of osteotomies around the knee. It was hypothesized that DVT would be detected at a substantial rate after the osteotomy, and there would be differences in the incidences among the different osteotomy procedures. METHODS: Consecutive patients who underwent knee osteotomies for varus osteoarthritis and met the inclusion criteria were included in the study. Ultrasonographic evaluation was performed to detect DVT on bilateral whole leg at 1 month before and 7 days after surgery. Statistical comparison of the demographic and clinical parameters between the patients with and without DVT as well as multivariate analysis using logistic regression was conducted to identify risk factors related to the incidence of postoperative DVT. RESULTS: The study subjects comprised 159 knees in 135 patients with medial opening wedge high tibial osteotomy (MOW-HTO), 93 knees in 78 patients with lateral closed wedge high tibial osteotomy (LCW-HTO), and 74 knees in 54 patients with double level osteotomy (DLO). In the postoperative evaluation, DVT was detected in 19 of 159 knees (11.9%) in MOW-HTO, 21 of 93 knees (22.6%) in LCW-HTO, and 5 of 74 knees (6.8%) in DLO. The incidence of DVT was significantly higher after LCW-HTO than after MOW-HTO and DLO (p < 0.01). DVT at a level above the knee was noted in one case after MOW-HTO, while DVT in the remaining cases developed at a level below the knee. No cases of symptomatic pulmonary embolism were encountered during the study period. Among the potential risk factors assessed for correlation with the incidence of DVT, LCW-HTO was identified as a significant risk factor (odds ratio: 2.54; 95% CI 1.334-4.836; p < 0.01). CONCLUSIONS: This study demonstrated that DVT occurred at a substantial rate (overall incidence of 13.8%) after osteotomy around the knee even with the use of prophylactic anticoagulant. Among the different osteotomy types, the DVT rate was significantly higher after LCW-HTO than after MOW-HTO and DLO. LEVEL OF EVIDENCE: Prospectively designed observational cohort study, Level III.

Return to sports rate after opening wedge high tibial osteotomy in athletes.

PURPOSE: We hypothesized that patient treated with OWHTO who participate in high-impact sports would attain satisfactory outcome. The purpose of this study was to examine the clinical and radiological outcomes in a consecutive series of opening-wedge high tibial osteotomy (OWHTO) in highly active patients. METHODS: Seventy-seven consecutive patients who underwent OWHTO with varus osteoarthritic knees were included in the study. The mean age of the study population was 56.1 years. All patients were followed for a minimum of 2 years. Clinical and radiological evaluations were performed at 12 and 24 months after surgery. The clinical results were evaluated using the Knee Injury and Osteoarthritis Outcome Score (KOOS) and the International Knee Documentation Committee (IKDC) Subjective Score. In regards to radiological assessment, the following parameters were measured in full-length weightbearing radiographs both pre- and postoperatively; mechanical tibiofemoral angle (mTFA), mechanical lateral distal femoral angle (mLDFA), and weight bearing line (WBL) ratio. RESULTS: Fifty-eight patients (75.3%) returned to the same high-impact sports activities as before surgery, with a mean time to return of 8.7 ± 2.7 months (6-14 months). In the clinical assessments, the IKDC subjective score and KOOS both improved from the mean preoperative scores of 38.4 and 217.4 points to the mean postoperative scores of 74.5 and 421.6 points, respectively. The mean pre-symptomatic Tegner activity scale was 5.3 ± 0.6 and significantly decreased to 4.8 ± 1.2 at 2 years postoperative (p < 0.05). In the radiological evaluation, the postoperative mTFA, mMPTA, and WBL ratio values averaged 1.3° ± 2.2° valgus, 90.7° ± 2.9°, and 51.6% ± 8.4°, respectively, at 24 months after surgery. CONCLUSIONS: Clinical outcomes based on postoperative patient-reported outcome measures and rate of return to high-impact sports activities were favorable after OWHTO in patients with knee OA who desired to continue sporting activities with the Tegner activity score of ≥ 5 points. LEVEL OF EVIDENCE: Retrospective case series, IV.

Physiologic knee joint alignment and orientation can be restored by the minimally invasive double level osteotomy for osteoarthritic knees with severe varus deformity.

PURPOSE: The purpose of this study was to examine early radiological and clinical outcomes following minimally invasive double level osteotomy (DLO) procedure performed for osteoarthritic knees with severe varus deformity. METHODS: Twenty consecutive patients who underwent DLO for varus osteoarthritic knees were included in the study. All patients could be tracked for a minimum of 1 year. Periodical radiological and clinical evaluations were performed at 6 and 12 months after surgery. In the radiological assessment, the following parameters were measured on full-length weight-bearing radiographs both pre- and postoperatively: mechanical tibiofemoral angle (mTFA), mechanical lateral distal femoral angle (mLDFA), mechanical medial proximal tibial angle (mMPTA), and joint-line convergence angle (JLCA). In addition, subjective clinical results were evaluated using the Knee Injury and Osteoarthritis Outcome Score (KOOS) and the International Knee Documentation Committee (IKDC) Subjective Score. RESULTS: The mean age of the study population was 62.5 ± 6.8 years (range 45-76 years). In the radiological evaluation, the preoperative mTFA, mLDFA, mMPTA, and JLCA values averaged 13.5° ± 3.1° varus, 91.1° ± 1.4°, 82.3° ± 2.0°, and 5.8° ± 2.3°, respectively. At 6 and 12 months, all of the radiological parameters significantly improved and corrected to the values within normal range. In the clinical assessments at the follow-up evaluations, both the KOOS and IKDC subjective scores significantly improved from the preoperative values. No significant changes were noted between the 6 and 12-month results in the radiological and clinical assessments. CONCLUSIONS: The minimally invasive DLO technique is a valuable surgical technique accomplishing restoration of physiologic knee joint alignment and orientation with significant improvement in patient-registered clinical outcomes in early postoperative evaluation. Although the follow-up period is still short, the excellent clinical and radiological outcomes shown in the present study support the efficacy of this procedure. LEVEL OF EVIDENCE: Retrospective case series, Level IV.

Achievement of optimal implant alignment using taper wedge stems with cup-first THA through the MIS antero-lateral approach.

PURPOSE: Combined anteversion (CA) technique (stem-first procedure) has become generally accepted as an ideal means to achieve optimal CA value in THA. However, we hypothesized that CA technique for patients with various native femoral anteversions could pose a risk of anterior or posterior cup protrusion. In the present study, we examined whether it is possible to use the taper wedge stem to change the stem version to achieve optimal CA while avoiding cup protrusions with the cup-first procedure through minimally invasive (MIS) antero-lateral approach. METHODS: Eighty-one patients underwent cup-first THA with a taper wedge stem. The acetabular cup was placed following the preoperative planning of the cup alignment to avoid anterior cup protrusions using CT-based navigation. Following the CA theory, anteversion of the taper wedge stem was changed to the target anteversion from the patient's native femoral anteversion. The native femoral anteversion, the change in version angle of the stem, postoperative CA and the length of anterior cup protrusions were evaluated in postoperative CT measurements. RESULTS: The native femoral anteversion averaged 25.7° ± 8.9° (range 8°-45°). Cases with increased and decreased stem anteversion were observed in 42 hips (51.8%) and 33 hips (40.7%), respectively. The amount of increased and decreased version angles averaged 7.7° ± 4.8° (range 2°-21°) and 7.8° ± 5.1° (range 2°-20°), respectively. Postoperative CA values averaged 36.7° ± 3.4° (range 29.4°-44.2°) and anterior cup protrusion length averaged 2.0 mm ± 2.6 mm (0 ~ 8.8 mm) in axial view and 0.4 mm ± 1.0 mm (0 ~ 3.6 mm) in sagittal view. Anterior cup protrusion of more than 10 mm was not observed in any hips. CONCLUSION: This procedure can be considered as an option to achieve optimal CA anteversion while avoiding anterior cup protrusion in THA.

New combined anteversion technique in hybrid THA: cup-first procedure with CT-based navigation.

PURPOSE: Combined anteversion (CA) technique (stem-first procedure) is generally accepted as the optimal technique to attain an appropriate CA value in total hip arthroplasty (THA). However, cup anteversion is strongly influenced by the native femoral anteversion. Accordingly, anterior protrusion of the cup in the acetabulum might occur. The purpose of the present study is to investigate the achievement of the optimal CA while avoiding anterior cup protrusion and examine the significance of our new CA technique with cup-first procedure in hybrid THA. METHODS: Seventy-nine hybrid THAs with the cup-first procedure used a CT-based navigation system for cup positioning. In the preoperative planning, cup anteversion was aimed at approximately 20°. However, in actuality, sufficient cup coverage in the original acetabulum based on individual anatomy is given priority over cup placement based on CT-based planning to ensure adequate cup coverage. The target stem anteversion was determined following Widmer's mathematical formula (37.3 = femoral stem anteversion × 0.7 + cup anteversion). Cemented stem was inserted according to the target stem anteversion angle. RESULTS: Regarding the assessment of overall alignment, the calculated Widmer's CA values during surgery and postoperative CT evaluation were 34.1° ± 6.0° (range 20.7°-51.2°) and 35.1° ± 6.7° (range 21.6°-50.7°). There were 72 hips (91.1%) within 25°-50° of CA. Cup protrusion length averaged 2.0 mm ± 2.6 mm (0-8.8 mm) in the axial view and 0.4 mm ± 1.0 mm (0-3.6 mm) in the sagittal view. Cup protrusion length of more than 5 mm was indicated in 10 hips, and no hips observed more than 10 mm. CONCLUSION: Our new CA technique (cup-first procedure) with hybrid THA was able to achieve optimal CA value while avoiding anterior cup protrusion.

Characteristic Poses in Ballet in the Case of a Retired Classical Ballerina after Bilateral THA: A Case Report and Review of Literature.

BACKGROUND: Ballet dance involves extreme range of motion (ROM) in the hip joint. This ROM can cause injuries including labral strain, tears, and subluxation episodes. Case Presentation. A 69-year-old female classical ballet dance instructor presented bilateral hip pain. The plain radiograph showed end-stage osteoarthritic change in the bilateral hip. She could neither dance nor perform daily activities. Bilateral hybrid total hip arthroplasty (THA) was performed. After surgery, she was able to demonstrate the split position on the floor as an active classical ballerina. The plain radiograph was taken in the split position, and the radiograph did not show any characteristics of impingement or subluxation of the femoral head. CONCLUSION: She was able to continue working as a classical ballet instructor after bilateral THA. Additionally, any characteristics of impingement or subluxation of the femoral head were not revealed in the postoperative radiograph in the split position.

Three dimensional CT analysis of the change in rotational alignment in double level osteotomy after double level osteotomy performed for varus osteoarthritic knees.

PURPOSE: To analyze the change in rotational alignment caused by double level osteotomy (DLO) based on comparative three-dimensional image analysis of pre- and postoperative CT images. METHODS: Pre- and postoperative CT examination of the lower extremities were performed with informed consent for 39 consecutive knees undergoing DLO for varus knee deformity. The DLO procedure consisted of closed wedge distal femoral osteotomy (CWDFO) and open wedge high tibial osteotomy (OWHTO). Among those cases, 20 knees complicated with hinge fracture at the osteotomy site were excluded from the analysis to eliminate a confounding factor affecting the results. Consequently, data obtained from 19 knees were subjected to the study analysis while osteotomies with hinge fractures complications were excluded from the study. In the three-dimensional CT image analysis of axial plane images, femoral torsion (the angle between midline along the femoral neck axis and the tangent of the posterior edges of the medial/lateral femoral condyles) and tibial torsion (the angle between the tangent of the posterior edges of the medial/lateral tibial condyles and the transmalleolar axis) were measured. The torsion angle was measured in each of the femurs and the tibias on both pre- and postoperative CT axial images, and the change induced by the osteotomy was calculated and statistically(using Wilcoxon signed-rank test) compared. RESULTS: The mean pre- and postoperative femoral torsion (anteversion) angles were 29.3° and 31.4° with a significant postoperative increase in internal rotation of the bony segment distal to the osteotomy(P = 0.002). On the tibial side, the mean pre- and postoperative torsion angles were 26.5° and 25.7°, indicating no significant postoperative change(P = 0.199)（NS）. CONCLUSIONS: This study showed that the DLO procedure (combining CWDFO and OWHTO) increased torsion (anteversion) of the femur by 2.1° on average while inducing no significant rotational change on the tibial side.

Double-level osteotomy for severe varus osteoarthritic knees can prevent change in leg length and restore physiological joint geometry.

BACKGROUND: It is unclear whether double-level osteotomy (DLO) combining closed-wedge osteotomy in the distal femur and open-wedge osteotomy in the proximal tibia deformity can prevent change in leg length and excessive coronal inclination of the tibial articular surface in surgical correction of the severe varus knee. The purpose of this study was to examine the postoperative change in leg length as well as radiological and clinical outcomes following DLO compared with the results obtained from knees undergoing isolated open-wedge high tibial osteotomy (OW-HTO). METHODS: In cases of severe varus knee deformity (hip-knee-ankle angle (HKA) > 10°) 29 patients undergoing DLO and 35 patients undergoing OW-HTO were included. If the predicted mechanical medial proximal tibial angle (mMPTA) was 95° or greater or the wedge size was 15 mm or greater in the surgical simulation, then DLO was considered as the surgical of option. In cases where these criteria were not met, OW-HTO was selected. All patients were followed up for a minimum of 2 years. RESULTS: The changes in the length of the whole leg in the DLO and OW-HTO groups averaged 2.3 ±â€¯4.8 mm and 9.3 ±â€¯7.2 mm, respectively (P < 0.001). mMPTA of more than 95° was found in no knee in the DLO group. CONCLUSIONS: This study showed that DLO could avoid leg length change and non-physiologic joint lines when performed in patients with varus HKA > 10°, and the predicted mMPTA was 95° or greater or the wedge size was 15 mm or greater in the surgical simulation.

Radiological Evaluation of the Relationship Between Cortical Hypertrophy and Stress Shielding After Total Hip Arthroplasty Using a Cementless Stem.

BACKGROUND: Unloading of the proximal medial femoral cortex is usually associated with an increased bone strain at the distal part of the prosthesis, which may cause distal femoral cortical hypertrophy (CH). The objective of this study was to determine the factors that may be considered a predisposition to distal femoral CH and its effect on the stress shielding (SS) or durability of the fixation of the stem. METHODS: A total of 240 total hip arthroplasties were performed between January 2006 and December 2016, with all hips implanted with a Bicontact stem. The minimum follow-up period was more than 2 years, and the mean follow-up period was 7.2 years. The radiographic outcome was assessed on an anteroposterior hip radiograph. CH and SS were assessed on postoperative radiographs in the Gruen zone. We defined CH that appeared in zone 3 or 5 as 'the focal type' and defined CH that appeared in zones 2, 3, 4, 5, and 6 as 'the diffuse type.' SS followed the procedures from the Engh classification. RESULTS: CH was found in 72 hips (30% of the 240 hips), the focal type was found in 23 hips (9.6% of the 240 hips), and the diffuse type was found in 49 hips (20.4% of the 240 hips). SS was found in 41 hips (17.1% of 240 hips), including 32 hips with SS, which was found after the development of CH. One hip was from the focal-type CH and 31 hips were from the diffuse-type CH. SS, which is typically found in Engh classification types 1 and 2 developed in 13 hips, and SS, which is widely seen in Engh classification types 3 and 4 developed in 19 hips. All 19 hips with progressed SS were found after the diffuse-type CH had developed. In addition, among the 19 hips with progressed SS, Dorr type A was found in 0 hips, Dorr type B in 8 hips, and Dorr type C in 11 hips. CONCLUSIONS: According to the results of our radiological evaluation, development of the diffuse-type CH after total hip arthroplasty using Bicontact stems is one of the critical causes of the later development of SS and could be predicted to progress to SS. To prevent the development of the diffuse-type CH, the indication to choose a Bicontact stem for a Dorr type C with osteoporotic bone should be considered.

Influence of Spinopelvic Alignment on Pelvic Tilt after Total Hip Arthroplasty.

OBJECTIVE: To evaluate the impact of spinopelvic parameters and hip contracture on change in the pelvic tilt (PT) after Total hip arthroplasty (THA). METHODS: One hundred patients (15 male and 85 female) who underwent THA were included in this prospective study. Radiographic data were obtained preoperatively and 1 year after THA. Radiographic parameters included sagittal anterior pelvic plane (APP), sagittal vertical axis (SVA), sacral slope (SS), pelvic inclination (PI), and lumbar lordosis angle (LL). The APP was defined as the angle between the anterior pelvic plane and the vertical plane. A positive value indicates pelvic retroversion. Postoperative changes in PT were divided into three groups: the PA group (pelvic anteversion, ΔAPP < -5°), the PR group (pelvic retroversion, ΔAPP > 5°), and the PT group (minimal change, ΔAPP ≤ ± 5°). The Kruskal-Wallis test and the Steel-Dwass test were used to compare the preoperative and postoperative spinopelvic parameters among the three groups. The Spearman's rank correlation coefficient was used to evaluate the correlation between ΔAPP and spinopelvic parameters. RESULTS: Minimal change in pelvic tilt was observed in 59% of patients, while pelvic anteversion was observed in 16% of patients and pelvic retroversion was observed in 25% of patients. There were no significant changes in the spinopelvic parameters, including TK, LL, SVA, LL, SS, and APP after THA. The Femoral angle (FA) was significantly decreased after THA (P < 0.001). Preoperative APP was significantly more retroverted in the PA group than the PR group, and the PT group (6.8 ± 12.2, 0.2 ± 9.9, -8.3 ± 8.3, P < 0.001). Preoperative SS, PI-LL, and PI were significantly smaller in the PA group than the PT group and the PR group. A significant negative correlation was identified between preoperative APP and ΔAPP (r = -0.418, P < 0.001). CONCLUSION: Approximately 60% of the patients did not have any marked change in PT after THA. Preoperative APP was the only predictive factor associated with marked anterior or posterior change in PT.