Minimally invasive distal linear metatarsal osteotomy combined with selective release of lateral soft tissue for severe hallux valgus.

BACKGROUND: Minimally invasive techniques for hallux valgus have been widely used to treat mild to moderate hallux valgus deformities. The purpose of this study was to evaluate the clinical and radiographic outcomes of distal linear metatarsal osteotomy (DLMO), which is one of the minimally invasive techniques, for severe hallux valgus. METHODS: 95 patients (141 feet) with severe hallux valgus underwent DLMOs. Lateral soft tissue release (LSTR) was performed at the same time for the cases selected by an original manual test. The satisfaction level, the Japanese Society of Surgery of the Foot (JSSF) hallux scale score, and weight-bearing radiographs of the foot were assessed preoperatively and after more than 24 months. In addition, the clinical and radiographic outcomes were compared among three groups divided by the kind of LSTR: no LSTR; manual correction; and open release through skin incision. RESULTS: Although the first metatarsal bone was significantly shortened, dorsiflexed, and elevated on postoperative radiographs, the rate of satisfaction was 87.2% (123/141), and the mean JSSF hallux scale score improved significantly from 60.4 (44-73) to 90.4 (65-100). The mean hallux valgus and intermetatarsal angles also improved significantly from 45.5° (40.0-60.0°) to 10.3° (-28.0-40.9°) and from 19.9° (14.0-28.7°) to 8.3° (-1.6-18.5°), respectively. Delayed union (18 feet), metatarsalgia (16 feet), recurrence (22 feet), and hallux varus (22 feet) were observed, and they were more obvious in DLMO combined with open release through a skin incision. CONCLUSIONS: DLMO combined selectively with LSTR is an effective procedure for correcting severe hallux valgus. However, the indication for open release with DLMO should be considered carefully.

Comparison between cylindrical axis-reference and articular surface-reference femoral bone cut for total knee arthroplasty.

PURPOSE: Reproducing a functional flexion-extension axis (FEA) of the femur is key to achieving successful collateral ligament balance and joint line in total knee arthroplasty (TKA). This study compared the feasibility of cylindrical axis (CA)-reference bone cut and articular surface-reference bone cuts in reproducing the FEA for Japanese osteoarthritis patients. METHODS: The study enrolled 122 knees from 86 patients who underwent primary TKA due to grade III or IV osteoarthritis. Data from pre-operative CT were reconstructed into three-dimensional (3D) models using 3D-planning software. Cylindrical radii of the condyles were measured, and femoral bone cut angles relative to anatomical landmarks were determined in the coronal and axial reference planes based on CA-reference and articular surface-reference methods. RESULTS: Mean cylindrical radii for medial and lateral femoral condyles were 17.4 ± 1.6 and 17.3 ± 1.4 mm, respectively. Of the 122 knees, 46 exhibited >1 mm of difference between condyles. Fifty-three and 22 knees exhibited >2° of angular difference between CA-reference and articular surface-reference bone cuts in the coronal and axial planes. Mean angle of the CA and surgical epicondylar axis in 3D space was 4.6 ± 2.1°. As practical parameters for TKA, the angle between CA and IM rod was significantly larger than that between the distal articular surface line and IM rod in the coronal plane (p < 0.0001), indicating that CA-reference involves a smaller valgus bone cut of the distal femur than articular surface reference. CONCLUSIONS: CA-reference bone cut of the femur is preferable to articular surface-reference bone cut for reproducing FEA in Japanese OA patients, in whom more than one-third of knees exhibited asymmetry of radii between medial and lateral condyles. In clinical practice, the CA-reference bone cut represents a good technical option for kinematically aligned TKA in the Japanese population.

Effects of femoral bone tunnel characteristics on graft-bending angle in double-bundle anterior cruciate ligament reconstruction: a comparison of the outside-in and transportal techniques.

PURPOSE: Bone tunnel creation techniques influence the 3-dimensional (3D) position of bone tunnels and graft-bending angle in anterior cruciate ligament (ACL) reconstruction. This study assessed graft-bending angle and 3D characteristics of femoral bone tunnels and compared them between outside-in (OI) and transportal (TP) techniques. METHODS: Participants comprised 64 patients who underwent anatomic double-bundle ACL reconstruction, allocated to OI and TP groups (n = 32 each). The graft orientation plane exhibiting the largest graft-bending angle at the femoral tunnel aperture with the knee in extension was reconstructed from CT data using 3D imaging software. In this plane, graft-bending angle was compared between the OI and TP techniques. RESULTS: Although positionings of the intra-articular apertures of the femoral and tibial bone tunnels were similar, several spatial parameters of bone tunnels differed between techniques. Graft-bending angles of both anteromedial and posterolateral bundles were significantly more acute with the OI technique than with the TP technique. On coronal-plane CT, angle of the bone tunnel axis relative to the distal condylar axis correlated negatively with graft-bending angle, while in the axial plane, angle of the bone tunnel axis relative to the posterior condylar axis correlated positively with graft-bending angle. Lysholm score, pivot shift test, and anteroposterior laxity at >2.5-year follow-up demonstrated no significant differences between techniques. DISCUSSION: Different bone tunnel directions in OI and TP techniques substantially affected graft-bending angle , despite similar positionings of the intra-articular apertures. Graft-bending angle with the OI technique was acute, but risk of posterior blowout of the lateral femoral condyle was decreased. Surgeons should create the femoral tunnel while considering an obtuse graft-bending angle without increasing the risk of posterior blowout. LEVEL OF EVIDENCE: III.

Responsiveness of the Self-Administered Foot Evaluation Questionnaire (SAFE-Q) in patients with hallux valgus.

BACKGROUND: In this study, we investigated the responsiveness of the Self-Administered Foot Evaluation Questionnaire (SAFE-Q) for patient's assessment before and after hallux valgus surgery. METHODS: Patient-reported answers on the SAFE-Q and Short Form-36 (SF-36) before and at a mean of 3-4 and 9-12 months after hallux valgus surgery were analyzed. Data of 100 patients (92 women, eight men) from 36 institutions throughout Japan were used for analysis. RESULTS: In all subscales of the SAFE-Q, the trend of increased scores after surgery was statistically significant (P < 0.001). Among the patients with available scores both before and at 9-12 months after surgery (n = 66), the largest effect sizes (ESs) were observed for shoe-related (1.60), pain and pain-related (1.05), and general health and well-being (0.84) scales. In the SF-36 (n = 64), the largest ES was observed for the bodily pain scale (0.86). Less notable changes were observed for the remaining SF-36 domains. CONCLUSION: The SAFE-Q is the first patient-reported outcome measure which includes a quality of life assessment of shoes. In our cohort, the most remarkable responsiveness was observed for the shoe-related subscale. Based on its responsiveness, the SAFE-Q appears to be sufficient for evaluation of foot-related quality of life before and after surgery.

Effects of Reduction Osteotomy on Gap Balancing During Total Knee Arthroplasty for Severe Varus Deformity.

This study aimed to assess the effects of down-sizing and lateralizing of the tibial component (reduction osteotomy) on gap balancing in TKA, and the clinical feasibility of an uncemented modular trabecular metal tibial tray in this technique. Reduction osteotomy was performed for 39 knees of 36 patients with knee OA with a mean tibiofemoral angle of 21° varus. In 20 knees, appropriate gap balance was achieved by release of the deep medial collateral ligament alone. Flexion gap imbalance could be reduced by approximately 1.7° and 2.8° for 4-mm osteotomy and 8-mm osteotomy, respectively. Within the first postoperative year, clinically-stable tibial component subsidence was observed in 9 knees, but it was not progressive, and the clinical results were excellent at a mean follow-up of 3.3 years.

Factors affecting the achievement of Japanese-style deep knee flexion after total knee arthroplasty using posterior-stabilized prosthesis with high-flex knee design.

BACKGROUND: Achievement of very deep knee flexion after total knee arthroplasty (TKA) can play a critical role in the satisfaction of patients who demand a floor-sitting lifestyle and engage in high-flexion daily activities (e.g., seiza-sitting). Seiza-sitting is characterized by the knees flexed >145º and feet turned sole upwards underneath the buttocks with the tibia internally rotated. The present study investigated factors affecting the achievement of seiza-sitting after TKA using posterior-stabilized total knee prosthesis with high-flex knee design. METHODS: Subjects comprised 32 patients who underwent TKA with high-flex knee prosthesis and achieved seiza-sitting (knee flexion >145º) postoperatively. Another 32 patients served as controls who were capable of knee flexion >145º preoperatively, but failed to achieve seiza-sitting postoperatively. Accuracy of femoral and tibial component positions was assessed in terms of deviation from the ideal position using a two-dimensional to three-dimensional matching technique. Accuracies of the component position, posterior condylar offset ratio and intraoperative gap length were compared between the two groups. RESULTS: The proportion of patients with >3º internally rotated tibial component was significantly higher in patients who failed at seiza-sitting (41 %) than among patients who achieved it (13 %, p = 0.021). Comparison of intraoperative gap length between patient groups revealed that gap length at 135º flexion was significantly larger in patients who achieved seiza-sitting (4.2 ± 0.4 mm) than in patients who failed at it (2.7 ± 0.4 mm, p = 0.007). Conversely, no significant differences in gap inclination were seen between the groups. CONCLUSIONS: From the perspective of surgical factors, accurate implant positioning, particularly rotational alignment of the tibial component, and maintenance of a sufficient joint gap at 135º flexion appear to represent critical factors for achieving >145º of deep knee flexion after TKA.

Asymmetry of the knee extension deficit in standing affects weight-bearing distribution in patients with bilateral end-stage knee osteoarthritis.

PURPOSE: The aim of this study was to evaluate weight-bearing distribution in patients with bilateral end-stage knee osteoarthritis (OA) and to clarify the gait parameters affecting the weight-bearing distribution during both standing and walking using gait analysis. METHODS: Twenty-five patients (averaged 71 years) with symptomatic bilateral end-stage medial knee OA participated in this study. They performed relaxed standing, placing one foot on a force plate and thereafter, level walking. First, knee resultant force was calculated on bilateral knees during standing. The knees in each patient were divided into Higher and Lower force side for the definition of dominant side limb. Second, gait parameters in each subject were compared between both sides. RESULTS: Each patient had large weight-bearing asymmetry, though passive range of motion, subjective pain level, femorotibial angle and radiographic disease severities were not significantly different between both sides. In standing, knees on Higher force side were significantly extended (11.2 ± 6.5°) than on Lower force side (14.4 ± 7.3°, P = 0.0086). Similarly, knees on Higher force side were also significantly extended at heel strike during gait. Besides, peak values of extension moment, knee adduction moment, knee adduction moment impulse and vertical force during gait were significantly greater on Higher force side. CONCLUSIONS: Ability to extend the knee in standing was considered to be an essential factor to decide loading condition. It is clinically important to examine the ability to extend the knee in standing when considering loading asymmetry during gait in patients with bilateral knee OA. LEVEL OF EVIDENCE: III.

Comparison of postoperative morbidity between simultaneous bilateral and staged bilateral total knee arthroplasties: serological perspective and clinical consequences.

The present study compared simultaneous and two-staged (stages 1 and 2 with 8-month interval on average) bilateral TKAs in terms of postoperative serological status and clinical consequences. The decrease in hemoglobin over 2 weeks postoperatively was similar between groups. C-reactive protein levels and creatine phosphokinase index peaking on day 2 were significantly higher in the simultaneous group than in either staged group (P<0.05). Incidence of DVT on day 7 tended to be higher in the simultaneous group, but the difference was not significant. Considering the approximately 8-month interval and 2-month earlier functional recovery with stage 2 TKAs, 6 months were saved with the simultaneous bilateral TKA group. Collectively, simultaneous bilateral TKA is likely to offer a safe and effective procedure in appropriate clinical settings involving anti-bleeding and anti-venous thromboembolism prophylaxis.

Female recreational athletes demonstrate different knee biomechanics from male counterparts during jumping rope and turning activities.

BACKGROUND: A variety of athletic exercises are performed in sports training or rehabilitation after knee injuries. However, it remains unclear whether males and females exhibit similar joint loading during the various athletic motions. The purpose of this study was to identify gender differences in knee biomechanics during the athletic motions. METHODS: Three-dimensional knee kinematics and kinetics were investigated in 20 recreational athletes (10 males and 10 females) while jumping rope, backward running, side running, side-to-side running, side-to-forward running, inside turning, and outside turning. The strengths of the quadriceps and hamstring muscles, the knee joint force, the knee joint angle, and the knee joint moment were compared between males and females using one-tailed t tests. RESULTS: Peak knee anterior force was greater in female recreational athletes than in their male counterparts during jumping rope, side-to-forward running, inside turning, and outside turning. Female subjects displayed greater peak knee abduction angles and greater peak knee flexion moments while jumping rope compared to their male counterparts. There were no significant differences between the sexes in knee kinematics and kinetics in the frontal and transverse planes during running and turning motions. CONCLUSIONS: Female recreational athletes exhibited significantly different knee biomechanics compared with male counterparts during jumping rope and turning motions.

Standard growth of the foot arch in childhood and adolescence--derived from the measurement results of 10,155 children.

BACKGROUND: The definition of flatfoot remains analytically vague. Toward the purpose of establishing the standard values of the foot length and arch height in childhood and adolescence, large-scale measurement and investigation of the foot arch were conducted using a three-dimensional foot-measuring device. METHODS: Measurements of foot structure were performed on 5311 boys and 4844 girls, for a total of 20,310 ft. of 10,155 children aged from 6 to 18 years during the 2006-2008 year period. The foot length (FL) and the navicular height (NH) were measured, and the arch height ratio (AHR (%)=NH×100/FL) was calculated. RESULTS: The FL in boys showed an extension from the age of 6 to 14 and nearly reached a plateau at 14 years old. In girls, the extension was observed from the age of 6 to 13, and the FL came to a plateau at 13 years old. The NH in boys increased from the age of 6 to 13. In girls, the NH increased from the age of 8 to 13. The AHR, presented a normal distribution, and no differences were observed in the distribution for all ages in boys and girls. In boys, the AHR was almost flat until 11 years old, but elevated in the 11-13 year age period. In girls, the AHR was almost flat until 10 years old, but elevated in the 10-12 year age period. CONCLUSIONS: We are certain that the data demonstrating the normal growth of the foot contribute to the diagnosis and treatment of the failure of the foot to thrive.

Lower limb kinematic changes during gait after hallux valgus surgery: A prospective observational study.

BACKGROUND: Patients with hallux valgus are known to alter lower limb joint kinematics during gait. However, little information is available about gait changes following hallux valgus surgery. We aimed to longitudinally investigate lower limb kinematic changes at the mid and terminal stances of gait after hallux valgus surgery. METHODS: This prospective observational study included 11 female patients (17 feet), who underwent first metatarsal osteotomy. Gait analyses were performed preoperatively and 1- and 2-year postoperatively using a three-dimensional motion capture system. Toe-out angle, ankle, knee, and hip joint angles during gait were calculated from the recorded data. The spatiotemporal parameters and these angles at the mid and terminal stances of gait were statistically compared between preoperative and postoperative periods. FINDINGS: All spatiotemporal parameters remained unchanged postoperatively. The toe-out angle was significantly greater at 1- and 2-year postoperatively. The ankle pronation angle, the knee abduction angle, and the hip adduction angle at the mid and terminal stances of gait were smaller postoperatively compared to the preoperative. These angular changes showed a similar trend at 1 and 2 years postoperatively. However, the postoperative changes of the sagittal joint angles were relatively small. INTERPRETATION: Hallux valgus surgery can affect the toe-out angle and the lower limb coronal kinematics at the mid and terminal stances of gait in patients with hallux valgus. However, surgical correction of hallux valgus deformity did not directly improve the gait characteristics in patients with hallux valgus.

A novel and reproducible reference axis for distal tibial axial rotation.

We hypothesized that the tibial plafond revealed a novel anatomical reference axis associated with the axial alignment through an image processing technique. The plafond axis (PLA) was defined as the line connecting the midpoints of the medial and lateral plafond margin. In terms of intraclass correlation coefficient, the reproducibility to identify the PLA was not less than that to identify a conventional trans-malleolar axis (TMA). When the proximal medial-lateral axis was applied, the tibial torsion with reference to the PLA and the TMA was 12.0° ± 8.4°, and 23.3° ± 8.6°, respectively. The PLA can be considered a reproducible reference and is expected to be applicable in preoperative planning as well as postoperative evaluation of the implant alignment in total knee arthroplasty.

Validity and reliability of a self-administered foot evaluation questionnaire (SAFE-Q).

BACKGROUND: The Japanese Society for Surgery of the Foot (JSSF) is developing a QOL questionnaire instrument for use in pathological conditions related to the foot and ankle. The main body of the outcome instrument (the Self-Administered Foot Evaluation Questionnaire, SAFE-Q version 2) consists of 34 questionnaire items, which provide five subscale scores (1: Pain and Pain-Related; 2: Physical Functioning and Daily Living; 3: Social Functioning; 4: Shoe-Related; and 5: General Health and Well-Being). In addition, the instrument has nine optional questionnaire items that provide a Sports Activity subscale score. The purpose of this study was to evaluate the test-retest reliability of the SAFE-Q. PATIENTS AND METHODS: Version 2 of the SAFE-Q was administered to 876 patients and 491 non-patients, and the test-retest reliability was evaluated for 131 patients. In addition, the SF-36 questionnaire and the JSSF Scale scoring form were administered to all of the participants. Subscale scores were scaled such that the final sum of scores ranged between zero (least healthy) to 100 (healthiest). RESULTS: The intraclass correlation coefficients were larger than 0.7 for all of the scores. The means of the five subscale scores were between 60 and 75. The five subscales easily separated patients from non-patients. The coefficients for the correlations of the subscale scores with the scores on the JSSF Scale and the SF-36 subscales were all highly statistically significantly greater than zero (p < 0.001). The means for the five JSSF Scale classification groups fell within a relatively narrow range, indicating that the SAFE-Q labels are sufficiently similar to permit their use for all of the JSSF Scale classifications. CONCLUSION: The present study revealed that the test-retest reliability is high for each subscale. Consequently, the SAFE-Q is valid and reliable. In the future, it will be beneficial to test the responsiveness of the SAFE-Q.

Admission screening form and osteoporosis educational appointment: a novel fracture liaison service system for identifying osteoporosis patients and facilitating medication initiation.

Our FLS team aimed to ensure that patients admitted to the orthopedic department were promptly initiated for medication and identify and initiate medication for patients admitted to other departments. Our innovative FLS system along with admission screening and osteoporosis education have proven effective in identifying patients with osteoporosis and initiating medication. PURPOSE: The fracture liaison service (FLS) plays a crucial role in the secondary prevention of fragility fractures by involving various medical professionals. Our FLS team had two goals for preventing primary and secondary fractures: ensuring that patients admitted to the orthopedic department were promptly initiated on medication and identifying and initiating medication for patients admitted to other departments. METHODS: From April 2020 to March 2023, we analyzed the number of dual-energy X-ray absorptiometry (DEXA) scans performed, the DEXA rate among patients with proximal femoral fractures, and the rate of medication initiation each year. Our hospital implemented the FLS system in April 2022. It is a unique system utilizing admission screening form and osteoporosis educational appointments conducted by rehabilitation staff to initiate medication for orthopedic and non-orthopedic patients. RESULTS: The average monthly number of DEXA scans increased significantly, with 47.7 in 2020, 57.0 in 2021, and 90.8 in 2022. The DEXA rate among proximal femoral fracture patients increased from 23.3% in 2020 to 88.1% in 2021 and 100% in 2022. The rate of treatment initiation also increased remarkably, from 21.7% in 2020, to 68.7% in 2021, reaching 97.8% in 2022. We performed 504 interventions, resulting in 251 patients diagnosed with osteoporosis, of whom 134 (56 from non-orthopedic departments) successfully started medication. CONCLUSIONS: Our innovative FLS system, incorporating an admission screening form and osteoporosis educational appointments, proved effective in identifying patients with osteoporosis and facilitating medication initiation, which will prevent both primary and secondary fractures.

Semaphorin 3A is expressed in human osteoarthritic cartilage and antagonizes vascular endothelial growth factor 165-promoted chondrocyte migration: an implication for chondrocyte cloning.

OBJECTIVE: Vascular endothelial growth factor 165 (VEGF165) and its receptors, including neuropilin 1 (NRP-1), are overexpressed in human osteoarthritic (OA) articular cartilage, although their functional roles in the cartilage are not fully understood. An axon-guidance molecule, semaphorin 3A (Sema3A), which binds to NRP-1, acts as an antagonist of VEGF signaling in endothelial cells. The aim of this study was to examine the expression of Sema3A and the functions of the VEGF165/Sema3A/NRP-1 axis in OA cartilage. METHODS: The expression of Sema3A in OA and normal cartilage samples was examined by real-time polymerase chain reaction and immunohistochemical analyses. Functional analyses of VEGF165 and Sema3A were carried out using OA chondrocytes in culture. The migration activity of chondrocytes was examined in a monolayer wound assay. The effects of Sema3A on VEGF165-induced up-regulation of matrix metalloproteinases (MMPs) and intracellular signaling were also studied in cultured chondrocytes. RESULTS: Sema3A expression was significantly elevated in OA cartilage as compared to normal cartilage. Sema3A immunoreactivity directly correlated with the Mankin score and with chondrocyte cloning. VEGF165 promoted the migration of chondrocytes, and this activity was suppressed by VEGF receptor 2 tyrosine kinase inhibitors. Sema3A antagonized the chondrocyte migration promoted by VEGF165, and the activity was blocked by a selective inhibitor of, or small interfering RNA for, Sema3A. VEGF165-induced overexpression of MMPs and phosphorylation of ERK and focal adhesion kinase in chondrocytes were inhibited by Sema3A. CONCLUSION: Our findings provide the first evidence that Sema3A is overexpressed, with a direct correlation with cloning, in OA cartilage and that it suppresses the VEGF165-promoted migration of chondrocytes. Our findings also suggest that Sema3A plays a role in chondrocyte cloning through inhibition of cell migration in OA cartilage.

Factors affecting anterior knee pain following anatomic double-bundle anterior cruciate ligament reconstruction.

PURPOSE: The purpose of this study was to evaluate the prevalence of anterior knee pain in anatomic double-bundle anterior cruciate ligament (ACL) reconstruction and to identify critical factors affecting postoperative anterior knee pain development. METHODS: Subjects comprised 171 patients (171 knees) who underwent anatomic double-bundle ACL reconstruction with a follow-up period of ≥2 years. The procedure used bone-patellar tendon-bone plus gracilis tendon (BTB-G) in 56 knees, semitendinosus tendon (ST) in 71 knees, and ST-G in 44 knees. Clinical results and prevalence and severity of anterior knee pain were assessed at 3 months and 2 years postoperatively. Clinical variables influencing anterior knee pain development at each postoperative period were subjected to univariate analysis, followed by logistic regression analysis to identify risk factors for anterior knee pain. RESULTS: Overall prevalences of anterior knee pain at 3 months and 2 years postoperatively were 42.0 and 11.1%, respectively. Use of BTB-G graft represented the highest prevalence of anterior knee pain between the 3 different grafts (P = 0.001); however, this statistical significance disappeared at 2 years postoperatively. Prevalence of postoperative extension deficit was significantly higher in anterior knee pain-positive cohort than in anterior knee pain-negative cohort at 3 months postoperatively. Level of quadriceps strength was significantly lower, and Lysholm score was significantly worse in anterior knee pain-positive cohort than in anterior knee pain-negative cohort at 2 years postoperatively. According to logistic regression analysis, knee extension deficit was a predisposing factor for the development of anterior knee pain at 3 months postoperatively (odds ratio, 2.76; P = 0.004); however, there was no significant predisposing factor for anterior knee pain at 2 years postoperatively. CONCLUSIONS: Knee extension deficit was an important predisposing factor for postoperative anterior knee pain in the early postoperative period, and anterior knee pain was associated with impaired quadriceps function and inferior subjective results over 2 years postoperatively. Early recovery of full extension may prevent postoperative development of anterior knee pain and achieve successful outcomes for ACL reconstruction. LEVEL OF EVIDENCE: Retrospective comparative study, Level III.

Effects of four different surgical approaches on intra-operative joint gap in posterior-stabilized total knee arthroplasty.

PURPOSE: The effects of surgical approaches and patellar positions on joint gap measurement during total knee arthroplasty (TKA) remain unclear. We hypothesized that joint gap changes with different knee flexion angles would not be consistent within four different approaches and two different patellar positions. METHODS: This study enrolled 80 knees undergoing posterior-stabilized TKA. For 60 varus knees, parapatellar, midvastus, and subvastus approaches were used in 20 knees each. For 20 valgus knees, a lateral subvastus approach was used. Component gap length and inclination were measured intra-operatively using a specific tensor device under 40 lb with the patella reduced or shifted laterally, at 0°, 45°, 90°, and 135° of knee flexion. RESULTS: Mean gap lengths at 45° and 90° of knee flexion were significantly larger with the parapatellar approach than with midvastus or lateral subvastus approaches (P < 0.05). Regarding gap inclination, varus angle increased linearly through the entire arc of flexion in all four approaches. When the patella was shifted laterally, gap lengths at 45°, 90°, and 135° were significantly reduced compared with those for the patella reduced in the subvastus approach, whereas gap length was constant in the parapatellar approach, regardless of patellar position. CONCLUSION: Joint gap kinematics was not consistent within four different approaches and two different patellar positions. Relatively large gaps at 45° and 90° were unique features for the parapatellar approach. Surgeons should be aware that the flexion gap is reduced when the patella is shifted laterally in vastus medialis-preserving approaches such as the subvastus approach. LEVEL OF EVIDENCE: II.

Effect of the posterior tibial and peroneal longus on the mechanical properties of the foot arch.

BACKGROUND: The mechanical properties of the foot are controlled by many structures including muscles, tendons, ligaments, tarsal joints and bones. Among them, muscles make the dynamic changes of foot alignment, especially the posterior tibial (PT) and peroneal longus (PL) which contribute to maintaining the foot arch. The purpose of this study was to quantify the effect of PT and PL on the foot mechanical properties. METHODS: The mechanical properties with a longitudinal load to the tibia was measured in eight cadaveric feet. The measurement was carried out with absence of tendon traction (control), the presence of isolated traction of each tendon of the PT or PL, and finally after simultaneous traction of both tendons. RESULTS: The bone displacement significantly decreased with tendon traction. The stiffness significantly increased with PT traction compared to control, and significantly decreased with PL traction and with traction of both tendons. Among the four testing conditions, the energy during loading was least with isolated PT traction. The energy dissipation rate was significantly increased with PL traction and with traction on both tendons, whereas no significant difference existed with PT traction compared to control. CONCLUSIONS: The PT increased the stiffness and reduces the energy stored in the foot. The PT acted to improve the energy efficiency of the load transmission. The PL decreased the stiffness and increased the energy stored. CLINICAL RELEVANCE: PT and PL muscles affect the foot arch. Excessive or insufficient traction may cause some foot disorders.

Patient-Reported Outcomes of Minimally Invasive Distal Linear Metatarsal Osteotomy for Hallux Valgus.

BACKGROUND: Modified Bösch osteotomy, or distal linear metatarsal osteotomy (DLMO), is one of the minimally invasive correctional operations for hallux valgus deformity. Although the clinical and radiographic results of DLMO have been previously shown, the relationship between clinical outcomes using a validated patient-reported outcome measure and radiographic corrections have yet to be evaluated. METHODS: A total of 70 patients (97 feet) treated at our hospital were included in the study. The Self-Administered Foot Evaluation Questionnaire (SAFE-Q) and radiographic data were evaluated at a minimum 1-year follow-up. RESULTS: Scores of all five SAFE-Q subscales showed a statistically significant improvement: pain and pain-related (from 63.3 to 86.6), physical functioning and daily living (from 81.3 to 92.7), social functioning (from 79.5 to 94.4), shoe-related (from 43.1 to 72.3), and general health and well-being (from 67.7 to 92.1). The mean hallux valgus angle improved from 39.1° to 9.3°, and the mean intermetatarsal angle improved from 16.6° to 7.0°. Recurrence and hallux varus at the final follow-up occurred in nine feet (9.3%) and 15 feet (15.5%), respectively. Four of the five SAFE-Q subscale scores improved significantly even in patients with hallux varus. CONCLUSIONS: Distal linear metatarsal osteotomy improves foot-related quality of life in patients with hallux valgus deformity despite of the high rate of postoperative radiographic complication, especially hallux varus. Patients might be willing to tolerate mild hallux varus after DLMO, as indicated by patient-centered clinical results.

Isolated Talonavicular Arthrodesis for Traumatic Talonavicular Arthritis: Report of 2 Cases With Gait Analyses.

Isolated talonavicular arthrodesis is one of the surgical procedures for patients with talonavicular arthritis. However, the 3-dimensional kinematic behavior of the hip, knee, and foot/ankle complex during walking after the arthrodesis remains unclear. The clinical outcomes and gait analyses of 2 cases who underwent isolated arthrodesis for talonavicular osteoarthritis with chronic dislocated navicular fracture are presented. Gait analysis was carried out in both cases 1 year after surgery to clarify the side-to-side differences in the ranges of motion of the hip, knee, and foot/ankle complex during walking. Both cases showed good clinical results and radiographic bone union. The kinematic data of the gait analyses showed considerable restriction in the range of motion of the ankle in all 3-dimensional planes for the fused foot compared with the contralateral side. Additionally, hyperextension of the knee in the late stance of gait on the operated side was observed in both cases. When talonavicular arthrodesis was performed for talonavicular osteoarthritis with chronic dislocated navicular fracture, postoperative generalized stiffness of the ankle and future disorder of the knee should be considered.Levels of Evidence: Level V: Case report.