Papers by Takafumi Hiranaka
Medicina
Background and Objectives: Unrestricted kinematic alignment total knee arthroplasty (KA-TKA) with... more Background and Objectives: Unrestricted kinematic alignment total knee arthroplasty (KA-TKA) with a soft-tissue respecting technique (STRT) is a soft-tissue-dependent tibial resection entailing the restoration of the original soft-tissue tension using ligamentotaxis after resurfacing the femur, based on the concept of restoring the native or pre-osteoarthritis alignment in each patient. However, there is no consensus on the indications of unrestricted KA-TKA with the STRT. We modified the STRT, followed by an investigation of the effects of surgery on the postoperative hip–knee–ankle angle (HKAA). Materials and Methods: We retrospectively analyzed the clinical background data, including the preoperative and postoperative HKAA, of 87 patients who underwent unrestricted KA-TKA with the modified STRT. Univariate and multivariate analyses were performed to determine the factors affecting the postoperative HKAA. A receiver operating characteristic (ROC) curve was plotted to investigate t...
Knee surgery & related research, Mar 14, 2022
The bone & joint journal, Jul 1, 2020
Aims. This multicenter study attempts to make recommendations as to when cementless Oxford Unicom... more Aims. This multicenter study attempts to make recommendations as to when cementless Oxford Unicompartmental Knee Arthroplasty (OUKA) tibial components can safely be used in an Asian population. Methods. 212 knees in 174 patients in six hospitals who underwent cementless OUKA were studied. On pre-operative radiographs the medial eminence line (MEL), which is a line parallel to the tibial axis passing through the tip of medial intercondylar eminence, was drawn. Knees were classified as having an overhanging condyle if the MEL passed medial to the medial tibial cortex and very small if a size A /AA tibial component was used. Results. Overall the fracture rate was 8%. With overhanging condyles the odds ratio of fracture was 13 (p<0.0001) and with very small components it was 7 (p=0.0004). With both overhanging condyles and very small components the odds ratio was 21 (p=0.0001). 69% of knees had neither overhanging nor very small components and in these the fracture rate was 1%. Conclusion. It is recommended that in Asia cemented tibial fixation should be used for cases that have overhanging condyles or need very small components. In the remaining 70% of cases cementless fixation can be used.
Knee Surgery & Related Research, 2022
Background Indication for mobile-bearing partial knee replacement (PKR) is made on the basis of a... more Background Indication for mobile-bearing partial knee replacement (PKR) is made on the basis of a radiological decision aid. This study aimed to reveal the inter-rater reproducibility and accuracy of the decision aid when used by experienced surgeons. Patients and methods Anonymised radiographic image sets (anteroposterior, lateral, varus/valgus stress in 20° knee flexion, and skyline views) from 20 consecutive patients who underwent knee replacement were assessed by 12 experienced surgeons. Agreements of each section and accuracy were compared by intra-operative inspection of the status of the anterior cruciate ligament (ACL) and medial and lateral cartilage according to the protocol of Radiographic Assessment for Medial Oxford PKR. Fleiss’ kappa (κ) values were used as a statistical measure. Results Full-thickness medial cartilage had the best agreement between the surgeons (κ = 94.7%) and best accuracy (94.2%). Although functioning ACL (90.8%), intact cartilage (91.7%) and full-t...
There are mixed views as to whether knee alignment can consistently predict incidence and/or prog... more There are mixed views as to whether knee alignment can consistently predict incidence and/or progression of tibiofemoral osteoarthritis (TFOA). Much of the literature on this subject reports knee alignment as either hip-knee-ankle angle (HKA-mechanical axis) or femoral-shaft tibial-shaft angle (FSTS-anatomical axis). This approach fails to take into account subjects where the overall angular deformity between the mechanical and anatomical axis differ. For example, there exists a population of individuals with medial compartment OA (MOA) that have a varus mechanical axis but valgus anatomical axis. If one were to compare the angular deformity to the location of TFOA in such a cohort, two very different outcomes are possible depending on which variable is used as a surrogate for overall knee alignment. Some of the current inconsistencies in the literature that compare the association of knee alignment to TFOA may be explained by failure to take into account angular orientation of both mechanical and anatomical axes, and also a lack of information regarding additional anatomical variables that may influence such axes. Femoral neck-shaft angle (NSA), femoral anteversion (FA), and tibial torsion (TT) are all likely to influence HKA and FSTS, yet there is little to no information about their association with different patterns of knee alignment or TFOA. Differences in such variables may help explain why there is a difference in anatomical versus mechanical axis in some patients with TFOA. The identification of all variables that influence knee alignment will help to more specifically define combinations that predispose TFOA. The aims of the current study are: 1) explore the various combinations of mechanical versus anatomical alignment among a cohort of subjects with primary end-stage knee OA, and 2) determine if NSA, FA, and TT are associated with differences in knee alignment. Methods: This retrospective, observational study reports on 48 subjects (96 hips/knees) with primary end-stage knee OA who presented to a single surgical centre for either total knee arthroplasty (TKA) or medial unilateral knee arthroplasty (UKA). All patients operated on by an author surgeon (TH) between November 2011 and August 2012 were included. Subjects were excluded if radiographic (N=8) or computed tomography (N=8) scans were unavailable. FA and TT were assessed from computed tomography (CT) imaging by previously defined methods. The HKA, FSTS, and NSA were assessed from full-limb, standing anteroposterior radiographs using OsiriX software (Orthopaedic Studio (customized version), Spectronic Medical AB, Helsingborg, Sweden). Both limbs from all patients were included in the analysis. Individual limbs were categorized based on the combination of angular deformity of both mechanical and anatomical axes. The four possible combinations of mechanical:anatomical axes included: 1) varus:varus, 2) varus:valgus, 3) valgus:varus, and 4) valgus:valgus. Femoral NSA, FA, and TT were then compared independently among the groups via analysis of covariance (ANCOVA), controlling for age, sex, and body mass index (BMI). Additionally, HKA and FSTS were compared to NSA, FA, and TT using Pearson bivariate correlation analysis. Results: Based on radiographic assessment of 10 subjects, the intra-class correlation coefficient for HKA, FSTS, NSA, FA, and TT were 0.99, 0.99, 0.91, 0.95, and 0.99 respectively. There were 48 knees in varus:varus alignment, 24 knees in varus:valgus alignment, and 10 knees in valgus:valgus alignment. Fourteen knees were unable to be categorized due to subluxation of the femur on the tibia. The ANCOVA analysis showed that between groups there was a significant difference in HKA (p<0.001), FSTS (p<0.001), NSA (p=0.014), and FA (p=0.002) (Table I). Pearson bivariate analysis showed a positive correlation between HKA and FA (r=0.412, p<0.001) and also HKA and TT (r=0.295, p=0.004). Additionally, there was a positive correlation between FSTS and FA (r=0.430, p<0.001) and also FSTS and TT (r=0.322, p=0.003). Therefore, as FA and TT increase, so do HKA and FSTS. An increase in FA was associated with an increase in TT (r=0.254, p=0.013). There was no correlation between NSA and either HKA or FSTS. Discussion: Our results illustrate the variability between the mechanical and anatomical axis of the knee in subjects with endstage OA. Even among this smaller cohort of subjects, nearly 30% of knees had mechanical and anatomical axes that differed in the direction of angular deformity. An increase in NSA, FA, and TT was more associated with a valgus:valgus alignment. The varus:valgus group also had an increased FA and TT as compared to the varus:varus group, but there was no difference in NSA between these latter two groups. These findings suggest FA and TT influence the anatomical axis more than the mechanical axis. The Pearson correlations confirm this, showing that FSTS has a stronger positive correlation with FA and TT than does HKA. This study demonstrates that the simple classification of a knee as either "varus" or "valgus" based on a single alignment in one
The Bone & Joint Journal, 2020
Aims Cementless unicompartmental knee arthroplasty (UKA) has advantages over cemented UKA, includ... more Aims Cementless unicompartmental knee arthroplasty (UKA) has advantages over cemented UKA, including improved fixation, but has a higher risk of tibial plateau fracture, particularly in Japanese patients. The aim of this multicentre study was to determine when cementless tibial components could safely be used in Japanese patients based on the size and shape of the tibia. Methods The study involved 212 cementless Oxford UKAs which were undertaken in 174 patients in six hospitals. The medial eminence line (MEL), which is a line parallel to the tibial axis passing through the tip of medial intercondylar eminence, was drawn on preoperative radiographs. Knees were classified as having a very overhanging medial tibial condyle if this line passed medial to the medial tibial cortex. They were also classified as very small if a size A/AA tibial component was used. Results The overall rate of fracture was 8% (17 out of 212 knees). The rate was higher in knees with very overhanging condyles (O...
Orthopaedics & Traumatology: Surgery & Research
Revue de Chirurgie Orthopédique et Traumatologique
Bone & Joint Research
The Knee, 2022
BACKGROUND Restricted kinematically-aligned total knee arthroplasty (KA-TKA) is a reasonable modi... more BACKGROUND Restricted kinematically-aligned total knee arthroplasty (KA-TKA) is a reasonable modification to avoid the alignment outlier that may cause implant failure. However, despite a noted high incidence of constitutional varus in Japanese individuals, there has been no investigation into how many knees require the restriction in restricted KA-TKA (RKA-TKA) among Japanese patients. Therefore, we conducted a study using preoperative long-leg radiograms. METHODS We studied long-leg radiographs of 228 knees in 114 consecutive patients. The numbers of knees within the safety range and their corrective osteotomy angle in the restriction algorithms advocated by Almaawi et al. (2017) and MacDessi et al. (2020) were evaluated. RESULTS According to the algorithms used by Almaawi et al. and MacDessi et al., out of 228 knees, 46 (20%) and 39 (17%) fell within the safety range, respectively. The mean correction angles of the hip-knee-ankle angle, lateral distal femoral angle and medial proximal tibial angle were 2.8 ± 3.4°, 0.4 ± 1.4° and 2.4 ± 2.8° in the algorithm used by Almaawi et al., while they were -4.9 ± 4.7°, 1.1 ± 2.5° and -6.0 ± 3.4° in the algorithm used by MacDessi et al. Most of the knees needed to be restricted in order to perform RKA-TKA, regardless of the algorithm used. CONCLUSIONS Based on a preoperative analysis of long-leg radiograms in a Japanese population, most knees fall out of the safety range in RKA-TKA. Surgeons must consider whether to allow component outlier or to perform corrective osteotomy that likely requires soft tissue release.
Archives of Orthopaedic and Trauma Surgery, 2022
Changes in bone mineral density (BMD) around the fully hydroxyapatite (HA)-coated compaction broa... more Changes in bone mineral density (BMD) around the fully hydroxyapatite (HA)-coated compaction broached and triple-tapered stem, namely, Polarstem, after total hip arthroplasty (THA) are currently unknown. Therefore, the aims of this study were to investigate clinical outcomes of Polarstem, mainly postoperative temporal changes in BMD around the stem for 2 years, and to compare them with those of HA-coated and non-HA-coated tapered-wedge stems. This retrospective cohort study enrolled 100 consecutive patients who underwent THA using Polarstem (n = 38), HA-coated Anthology (n = 31), and non-HA-coated Anthology (n = 31). BMD was evaluated using dual-energy X-ray absorptiometry in seven regions according to the Gruen zones. Postoperatively, BMD around the stem was assessed within 2 months (baseline BMD) and at 6, 12, and 24 months. A change in BMD was defined as the value calculated by dividing each postoperative BMD value at 6, 12, and 24 months by the baseline BMD value. Changes in BMD and radiographic parameters such as stress shielding and spot welds were compared among the three stems. The incidence rate of stress shielding in the Polarstem group was significantly lower than those in the other two groups (p = 0.007). The change in BMD in Zone 7 of Polarstem was significantly more than that of the other two groups at 12 and 24 months postoperatively (p = 0.030 and p = 0.009, respectively). Polarstem, a fully HA-coated compaction broached and triple-tapered stem, maintained BMD around the femoral calcar until 2 years postoperatively and could reduce the risk of stress shielding compared with tapered-wedge stems.
Clinics in Orthopedic Surgery, 2021
In Oxford unicompartmental knee arthroplasty, the relationship between the mobile bearing and the... more In Oxford unicompartmental knee arthroplasty, the relationship between the mobile bearing and the vertical wall of the tibial tray is important in preventing bearing dislocation. Separation of the bearing from the vertical wall can cause spinning of the bearing with an increased risk of subsequent dislocation. We report on intraoperative adjustment of the tibial tray performed to prevent the bearing from spinning. After tibial and femoral bone cutting and adjustment of the flexion and extension gap, the trial bearing is inserted and the bearing-vertical wall distance is evaluated before the preparation using the tibial template and bearing trial. In the case of separation, it can be resolved by medialization with or without rotational adjustment. The technique is useful and can be easily performed, it is therefore recommendable for all cases of Oxford mobile-bearing unicompartmental arthroplasty.
The ligament balance as well as the alignment is essential for successful total knee arthroplasty... more The ligament balance as well as the alignment is essential for successful total knee arthroplasty (TKA). However it is usually assessed and adjusted only at 0? and 90?. In order to evaluate the ligament balance at the other angles we have used a navigation system. Twenty-one patients underwent posterior stabilised mobile bearing TKA using a CT-based navigation system were included in this study. Immediately post-operation and still under anaesthesia, varus and valgus stresses were applied on operated knees manually at 0?, 30?, 60?, 90? and 120?. The ligament balance was calculated based on the angles under varus and valgus stress displayed on the navigation screen, presenting a relationship between the femoral and tibial cutting planes. The mean ligament balance angle at 0?, 30?, 60?, 90? and 120? were −2? ± 3.6?, −5.8? ± 7.9?, 5.0? ± 6.9?, −1.3? ± 5.4?, 7.9? ± 7.2?, respectively. At 0? and 90? balance was well adjusted, however in the other angles, it was quite varied. At 30? and 1...
The Knee, 2020
Protein kinase C signals thromboxane induced increases in fibronectin synthesis and TGF.p bioacti... more Protein kinase C signals thromboxane induced increases in fibronectin synthesis and TGF.p bioactivity in mesangial cells. Previous studies have demonstrated that thromboxane (TX) stimulates matrix protein synthesis in mesangial cells (MC), and that this action is signalled by receptor mediated activation of protein kinase C (PKC). In the present study, we examined the hypothesis that activation of PKC by TX signals increases in transforming growth factor /3 (TGF-/3) bioactivity, which in turn induces enhanced matrix protein synthesis. In cultured rat MC, the TXAJ prostaglandin endoperoxide analogue U-46619, but not exogenous human platelet TGF-/31, activated PKC as reflected by enhanced in situ phosphorylation of MARCKS protein, an endogenous substrate of PKC. U-46619 and TGF-/31 stimulated fibronectin (Fn) synthesis in MC, as shown by [35S]methionine incorporation into immunoprecipitable Fn. Pan-specific rabbit anti-TGF-f3 antibody blocked the increases in Fn synthesis induced by exogenous TGF-/3 and those induced by U-46619 at 24 to 72 hours after addition. Anti-TGF-/3 antibody did not block the small increases in Fn synthesis observed six hours after addition of U-46619, suggesting that this acute response was not dependent on TGF-/3. Anti-TGF-13 antibody also failed to block activation of PKC by U-46619. U-46619 and 50 n of the PKC agonist phorbol dibutyrate (PDBu) significantly increased both the active fraction and total (latent plus active) TGF-/3 in MC culture media, as assayed with the mink lung epithelial cell bioassay system. PKC inhibition with bisindolylmaleimide GF 109203X (GFX) or down-regulation of PKC in MC by prior exposure to a high concentration (0.5 j.tM) of phorbol myristate acetate (PMA) blocked increases in TGF-/3 bioactivity induced by either U-46619 or PDBu. PKC down-regulation in MC also blocked increases in Fn synthesis induced by U-46619. By contrast, exogenous TGF-/3 stimulated Fn synthesis in both intact MC and in MC with down-regulated PKC. The findings indicate that activation of PKC by U-46619 signals an increase in TGF-j3 bioactivity, which in turn stimulates Fn synthesis in MC by processes not dependent on PKC. examined the possibility that TX activation of PKC is a signal to increase TGF-/3 bioactivity in MC, which in turn mediates the sustained increases in Fn synthesis observed in response to TX. Methods Rat MC culture
Journal of Bone and Joint Surgery-british Volume, 2013
Introduction In most cases of stable type medial femoral neck fracture and some cases of dislocat... more Introduction In most cases of stable type medial femoral neck fracture and some cases of dislocated medial femoral neck fracture, internal fixation was undertaken. Dual SC Screw (DSCS) System is an internal fixation device which has sliding mechanism and preventing mechanism of back out of the screw. The purpose of this study is to evaluate the results and complication of medial femoral neck fracture treated with DSCS. Methods Fifty two patients operated for fractures of the medial femoral neck with DSCS were identified as the study population. All patients followed up at least 2years. Outcome measures included the period of bone union, revision surgery, operating times and clinical symptoms and complication. Results The average operation time was 37 minutes and 49 cased achieved union. Moreover all patients could regain the pre-injury walking ability. Three patient did not achieve union and two patients suffered displacement of reduced fracture and three patients had avascular necr...
Clinics in Orthopedic Surgery, 2021
In surgical treatment of femoral neck fractures, arthroplasty (AR) allows for low complication ra... more In surgical treatment of femoral neck fractures, arthroplasty (AR) allows for low complication rates and high postoperative functional improvement and is thus preferred to internal fixation (IF). 1) Conversely, IF has been reported to cause comparatively minor damage to soft tissue, require shorter operation times, and result in less intraoperative blood loss than AR. 2) In the IF technique, fixation is typically performed using multiple screws (MS) 3) or compression hip screws (CHS). Hanson pins 4) are often used instead of MS in Sweden and Japan. Compared to CHS, the MS technique has advantages (less invasiveness and less blood loss), but its stability is dependent on the three-point theory. 5) The reoperation rate when using CHS is, therefore, lower than that when using MS, and many reports recommend the use of CHS. 3,6
Surgical Innovation, 2017
Background. Smart glasses (SG) are a wearable device consisting of a small computer built into a ... more Background. Smart glasses (SG) are a wearable device consisting of a small computer built into a head-mounted monitor (HMM) that can display various kinds of information. Lateral side visualization is displayed on the HMM of SG so the operator may also see it and the anteroposterior (AP) direction simultaneously. The present pilot study aimed to investigate the usefulness of SG in wire insertion for bone fracture. Methods. We marked both the front and lateral sides of the shaft of an artificial femur bone. From the tip of the greater trochanter, we inserted a 2.4-mm Kirschner wire (K-wire) so that it could be directed toward the marks in both planes. Three surgeons enrolled in the study each performed 10 trials, both with SG (SG arm) and without (direct vision arm). We defined the error angle as the angle between the K-wire and the line connecting the marking point from the insertion point in both the front and lateral view images. We also measured the time it took to insert the K-wire in both arms. Results. The SG had a significantly reduced (mean = 3.2°) error angle (P = .02) when compared to the direct vision group (mean = 4.8°). However, no significant difference was found between direct vision (mean = 17.5 seconds) and SG arms (mean = 14.9 seconds) in the insertion time. Conclusion. While keeping the AP image view in primary focus, simultaneously viewing the lateral side of the surgical field using SG helps achieve more accurate wire insertion in surgery.
The Knee, 2021
BACKGROUND Lateral unicompartmental knee arthroplasty (UKA) leads to good clinical outcomes for i... more BACKGROUND Lateral unicompartmental knee arthroplasty (UKA) leads to good clinical outcomes for isolated lateral osteoarthritis. However, the impact of the tibial component position on postoperative outcomes in lateral UKA is yet to be determined. PURPOSE This study investigated the influence of tibial component malposition on clinical outcomes in lateral UKA. MATERIALS This was a retrospective study of 50 knees (mean age 73.5 years) who underwent lateral UKA between September 2013 and January 2019. The Oxford Knee Score (OKS), Knee Society Score - Knee (KSSK), and Knee Society Score - Function (KSSF) were evaluated. The coronal alignment, posterior slope of tibial component, tibial component rotation relative to Akagi's line (angle α), and femoral anteroposterior (AP) axis (angle β) were measured postoperatively. The average follow up period was 2.3 (range, 1-4.9) years. RESULTS Clinical scores were significantly improved after lateral UKA. The mean coronal alignment was 0.9° ± 3.2° varus (range, 9.1° varus to 5.5° valgus), the mean posterior slope was 6.8° ± 3.8° (range, 0.8° to 14.8°). The mean α and β angles, were 4.1° ± 5.8° (range, -9.7° to 16.5°) and 6.7° ± 7.1° (range, -7.0° to 20.5°) external rotation. The angle α had significant negative correlations with postoperative OKS (r = -0.36), KSSK (r = -0.28), and KSSF (r = -0.39), and angle β had significant negative correlations with postoperative OKS (r = -0.34) and KSSK (r = -0.46). CONCLUSION Excessive external rotation of the tibial component could negatively influence the postoperative outcomes of lateral UKA.
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Papers by Takafumi Hiranaka