早川 和恵

OBJECTIVES: Whether to resurface the patella in total knee arthroplasty for patients with rheumatoid arthritis remains controversial. This study evaluated long-term clinical and radiographic outcomes after total knee arthroplasty without patellar resurfacing. METHODS: Of 100 knees in 74 patients who underwent total knee arthroplasty without patellar resurfacing, 64 knees in 49 patients were available for follow-up (mean, 13.6 years). Clinical evaluations included the presence of anterior knee pain (AKP) at final follow-up, Knee Society Score, Knee Society Functional Score, and Kujala score. Plain radiographic evaluations assessed patellar thinning and its relationship with clinical outcomes. We also compared outcomes between remission and non-remission groups based on Disease Activity Score in 28 joints using C-reactive protein at final follow-up. RESULTS: The incidence of AKP was 9.3%. At follow-up, Knee Society Scores and Functional Scores had improved significantly (P < .05). Although patellar thinning progressed, it did not appear to affect clinical outcomes or incidence of AKP. Disease activity did not differ significantly between groups or by presence of AKP. CONCLUSIONS: Long-term outcomes of total knee arthroplasty without patellar resurfacing in rheumatoid arthritis were favourable, indicating that this approach is acceptable.

OBJECTIVES: Whether to resurface the patella in total knee arthroplasty for patients with rheumatoid arthritis remains controversial. This study evaluated long-term clinical and radiographic outcomes after total knee arthroplasty without patellar resurfacing. METHODS: Of 100 knees in 74 patients who underwent total knee arthroplasty without patellar resurfacing, 64 knees in 49 patients were available for follow-up (mean, 13.6 years). Clinical evaluations included the presence of anterior knee pain at final follow-up, Knee Society Score, Knee Society Functional Score and Kujala score. Plain radiographic evaluations assessed patellar thinning and its relationship with clinical outcomes. We also compared outcomes between remission and non-remission groups based on Disease Activity Score in 28 joints using C-reactive protein at final follow-up. RESULTS: The incidence of anterior knee pain was 9.3%. At follow-up, Knee Society Scores and Functional Scores had improved significantly (p < 0.05). Although patellar thinning progressed, it did not appear to affect clinical outcomes or incidence of anterior knee pain. Disease activity did not differ significantly between groups or by presence of anterior knee pain. CONCLUSIONS: Long-term outcomes of total knee arthroplasty without patellar resurfacing in rheumatoid arthritis were favourable, indicating that this approach is acceptable.

INTRODUCTION: With ongoing societal aging, the demand for regenerative medicine has increased. Recently, reports demonstrating the efficacy of knee regenerative therapies have increased, although substantial proportions of these studies involved relatively younger populations. However, in Japan, where our hospital is located, it is common for patients well beyond the WHO-defined elderly age of 65 years to present with a desire for regenerative therapy. This retrospective cohort study investigated the utility of autologous protein solution (APS) knee joint injections by comparing their effects in patients aged 80 years and older and those younger than 80 years. METHODS: From July 2021 to August 2023, we administered single APS injections into the knee joints of patients diagnosed with osteoarthritis. Clinical assessment was conducted at baseline and at one and six months post-injection. Forty-one patients (44 knees) who completed all scheduled assessments were included in this analysis. Subjects were stratified into group E (≥80 years old) or group Y (<80 years old). Clinical evaluations included assessments of joint range of motion, inflammatory biomarkers (C-reactive protein), radiographic Kellgren-Lawrence classification, MRI findings including bone marrow edema, and standardized patient-reported outcome measures (Knee Injury and Osteoarthritis Outcome Score {KOOS} and Knee Society Score {KSS}), with KSS subdomain scores normalized to a 100-point scale. RESULTS: No distinct intergroup differences were observed for knee range of motion, blood test parameters, or MRI findings. Group E had the highest scores on the KOOS activities of daily living and quality of life subscales at one month post-APS administration; both subscale scores decreased at six months post-administration, whereas these subscale scores consistently increased over time in group Y. Compared with the findings in prior research reporting the minimum clinically important difference after platelet-rich plasma administration, the findings at six months after APS administration were superior for all KOOS subscales, excluding sports, in both groups. Concerning KSS scores, most subscale scores consistently increased throughout the follow-up period in both groups, whereas the expectation subscale score tended to decrease over time, likely reflecting the evolution of expectations after surgery. CONCLUSIONS: Intra-articular APS injections demonstrated clinical efficacy in patients aged 80 years and older. When the analysis was limited to those who continued follow‑up at both one and six months after treatment, a tendency toward a shorter duration of effect was still observed, indicating the need for careful patient selection.

INTRODUCTION: Hallux hyperdorsiflexion and stiffness are typically associated with hallux rigidus. Although the underlying cause remains unclear, this case appears to have arisen in a patient undergoing treatment for schizophrenia, highlighting the importance of individualized and carefully tailored treatment approaches to achieve optimal patient outcomes and maintain high-quality care. CASE REPORT: A 71-year-old Asian woman undergoing treatment for schizophrenia presented with severe hyperdorsiflexion and stiffness of the right hallux, causing intense pain, which was particularly noticeable during gait and daily activities. Initially, the patient underwent rehabilitation to restore normal active motion of the right extensor hallucis longus (EHL). However, despite continuous rehabilitation, the stiffness persisted. Consequently, the patient underwent surgery involving dissection, lengthening of the distal EHL, and partial transposition of the proximal EHL. Postoperatively, the patient regained active hallux movement and showed significantly improved gait. CONCLUSION: Surgical treatment should be considered as an alternative option if symptoms persist for long in patients with hallux hyperdorsiflexion and stiffness. However, this approach is technically demanding and requires careful consideration of the strategy for successful recovery and optimal patient outcomes.

BACKGROUND: Fractures are a significant health concern for older adults, affecting their activities of daily living (ADL), physical function, and mental well-being, and contributing to the need for long-term care. However, the factors associated with fractures among independent older adults remain unclear. This study aimed to examine the association between fractures and the health status of independent older adults in a representative suburban city in Japan using data from a survey of community-dwelling residents and to identify factors associated with fractures. METHODS: A total of 15,853 survey questionnaires were mailed, and 11,346 valid responses were received, resulting in a response rate of 71.6%. The survey included questions on ADL, physical function, mental health, memory, medical conditions, and subjective complaints. For fractures, participants were asked the following question: "How many times have you experienced fractures since the age of 65?". Data were analyzed using Poisson regression models adjusted for age, sex, body mass index, family structure, and smoking history. RESULTS: Among the respondents, 15% reported fractures after age of 65 years. A decline in ADL, physical function, mental health, and memory were significantly associated with increased fracture frequency. Under medical conditions, the prevalence of depression (p for trend = 0.042), respiratory diseases (p for trend = 0.001), and ophthalmologic conditions (p for trend = 0.002) increased significantly with fracture number. Most subjective complaints were significantly associated with fracture number, with dysphagia demonstrating the strongest association. CONCLUSIONS: This study utilized a relatively large and highly representative sample of community-dwelling residents to identify factors associated with fractures in independent older adults. Even in independent older adults who were not certified as requiring long-term care, fractures were significantly associated with a decline in multiple health domains. These findings provide valuable insights that can inform efforts to promote healthy aging and reduce care dependency. CLINICAL TRIAL: Not applicable.

BACKGROUND: In total knee arthroplasty (TKA), cementless fixation is initially weaker than cement fixation. This study aimed to examine whether filling the tibial peg holes with bone improves initial fixation strength in cementless TKA. METHODS: This prospective, comparative study examined 88 joints in 66 patients randomized to the bone filling (48 joints) or conventional group (no bone filling; 40 joints). All patients underwent TKA with the NexGen® trabecular metal modular tibial component. In the bone filling group, resected cancellous bone was filled into the peg holes before insertion of the tibial component. We performed clinical and plain radiographic evaluations after the operation and measured bone mineral density (BMD) at five sites below the component at 1, 3, 6, and 12 months postoperatively. RESULTS: Operative time and clinical evaluations were not significantly different. Plain radiography showed significant longitudinal thickening of the trabecula below the peg (P<0.05) and decreased occurrence of reactive lines (P=0.07) in the bone filling group compared with the conventional group. BMD was significantly higher in the bone filling group in the medial region below the peg at 1, 3, and 6 months and in the central region at 1 and 3 months (all P<0.05). CONCLUSIONS: When using the NexGen trabecular metal modular tibial component, concurrent peg hole bone filling increases the initial component fixation strength. Possible effects on long-term stabilization warrant further study.

BACKGROUND: Managing medication use in older orthopedic patients is imperative to extend their healthy life expectancy in an aging society. However, the actual situation regarding polypharmacy, the intake of potentially inappropriate medications (PIMs), and fall risk-increasing drugs (FRIDs) among older orthopedic patients is not well characterized. This study aimed to investigate the medication-based profiles of older orthopedic patients to highlight the critical points of concern. METHODS: We retrospectively reviewed the clinical data of consecutive patients aged ≥ 65 years who underwent orthopedic surgery at two acute care hospitals between April 2020 and March 2021. The cutoff number of prescribed drugs for polypharmacy was set at 6. According to the specified guidelines, 19 categories of drugs were identified as PIMs, and 10 categories were classified as FRIDs. RESULTS: A total of 995 older patients with orthopedic surgery were assessed, of which 57.4% were diagnosed with polypharmacy, 66.0% were receiving PIMs, and 41.7% were receiving FRIDs. The prevalence of FRID intake did not significantly differ among patients with degenerative spinal disease (n = 316), degenerative disease of extremities (n = 331), and fractures (n = 272). Compared with patients with degenerative disease of the extremities, the multivariable-adjusted prevalence ratios (PRs) of polypharmacy and PIM intake were significantly higher in patients with degenerative spinal disease (1.26 [confidence intervals (CI): 1.11-1.44] and 1.12 [CI: 1.00-1.25]), respectively. Use of antiemetic drugs (adjusted PR, 13.36; 95% CI: 3.14-56.81) and nonsteroidal anti-inflammatory drugs (adjusted PR, 1.37; 95% CI: 1.05-1.78) was significantly higher in patients with degenerative spinal disease. Among patients with degenerative spinal disease, the prevalence of antiemetic drug intake was 8.7% in lumbar spinal patients and 0% in cervical spinal patients. CONCLUSIONS: More than half of the orthopedic patients in this study were affected by polypharmacy, and approximately two-thirds were prescribed some form of PIMs. Patients with degenerative spinal disease showed a significantly higher prevalence of polypharmacy and PIM use compared with other orthopedic diseases. Particular attention should be paid to the high frequency of antiemetic drugs and nonsteroidal anti-inflammatory drugs intake among patients with degenerative lumbar spine conditions.

BACKGROUND: In total knee arthroplasty (TKA), cementless fixation is initially weaker than cement fixation. This study aimed to examine whether filling the tibial peg holes with bone improves initial fixation strength in cementless TKA. METHODS: This prospective, comparative study examined 88 joints in 66 patients randomized to the bone filling (48 joints) or conventional group (no bone filling; 40 joints). All patients underwent TKA with the NexGen® trabecular metal modular tibial component. In the bone filling group, resected cancellous bone was filled into the peg holes before insertion of the tibial component. We performed clinical and plain radiographic evaluations after the operation and measured bone mineral density (BMD) at five sites below the component at 1, 3, 6, and 12 months postoperatively. RESULTS: Operative time and clinical evaluations were not significantly different. Plain radiography showed significant longitudinal thickening of the trabecula below the peg (P<0.05) and decreased occurrence of reactive lines (P=0.07) in the bone filling group compared with the conventional group. BMD was significantly higher in the bone filling group in the medial region below the peg at 1, 3, and 6 months and in the central region at 1 and 3 months (all P<0.05). CONCLUSIONS: When using the NexGen trabecular metal modular tibial component, concurrent peg hole bone filling increases the initial component fixation strength. Possible effects on long-term stabilization warrant further study.

INTRODUCTION: Fractures are often caused by falls in older people. Among various causes of falls, polypharmacy is known to be a risk of falls. Furthermore, potentially inappropriate medicines (PIMs), which interact with polypharmacy, include the drugs involved in falls. Here, we primarily aimed to investigate the prescribed drugs in older surgical patients with extremity fractures to determine the frequency of polypharmacy and identify PIMs. The second aim was to clarify the characterization of prescribed drugs of older patients with hip fracture. MATERIALS AND METHODS: We retrospectively collected the following clinical data of consecutive patients aged ≥65 years who underwent surgery for extremity fractures at our hospital between April 2019 and March 2021. A total of 19 categories were considered as PIMs. The Poisson regression models were used to examine the association between the number of prescribed drugs and hip fracture prevalence. RESULTS: A total of 590 patients were reviewed. Our data showed that 55% of older patients with extremity fractures took ≥6 prescription drugs. The frequency of prescription of hypnotics, antithrombotic drugs, diuretics, and non-steroidal anti-inflammatory drugs was comparatively high among the 19 categories of PIMs. Multivariable analysis revealed that polypharmacy was significantly associated with hip fractures. Among PIMs, antithrombotic drugs and diuretics were significantly associated with the prevalence of hip fractures. Finally, we found a significant positive association between the prevalence of hip fracture and the number of drug categories of PIMs among older patients with extremity fractures. CONCLUSIONS: The present study clarified the characterization of the prescribed drugs in older surgical patients with extremity fractures. Special attention should be paid to hip fractures of older patients with polypharmacy or prescribed with many drugs categories of PIMs, particularly antithrombotic drugs and diuretics.

INTRODUCTION: Efforts are being made to reduce doctors' working hours and implement reforms in the way doctors work. This study aims to determine the associations between depressive symptoms and work environment/lifestyle among <40-year-old male orthopedic physicians in Japan. METHODS: Participants were 1,343 male orthopedic physicians selected from a survey (N = 25,139) of all regular members conducted in 2019 by the Japanese Orthopaedic Association. Participants completed the Quick Inventory of Depressive Symptomatology and provided information about total working hours, number of on-call/night duties, number of patient complaints received, smoking habits, exercise habits, and sleep time. RESULTS: Of the participants, 6.6% had depressive symptoms. Factors associated with depressive symptoms were total working hours of ≥80 h per week (80-99 h: adjusted odds ratio [AOR] = 2.06; 95% confidence interval [CI], 1.02-4.18; ≥100 h: AOR = 3.89; 95% CI, 1.92-7.88), one or more unreasonable patient demands/complaints in the previous 6 months (AOR = 1.61; 95% CI, 1.00-2.60), current smoking (AOR = 2.98), no sweat-inducing exercise sessions of ≥30 min per week in the previous month (AOR = 2.50), and an average of <6 h of sleep per night in the previous month (AOR = 2.15). CONCLUSIONS: Work factors at the main medical institution (i.e., total working hours of ≥80 h per week) were associated with depressive symptoms. In addition, associations between depressive symptoms and unhealthy living conditions, such as smoking habits, lack of exercise, and <6 h of sleep per night, were observed.

AIMS: Elderly patients with musculoskeletal disorders are generally expected to receive many prescription drugs for non-musculoskeletal comorbidities and for alleviating chronic musculoskeletal pains. The aims of this study were to review the use of prescription drugs in elderly patients with elective surgeries for musculoskeletal disorders and to identify the factors associated with polypharmacy in elderly patients with musculoskeletal disorders. METHODS: We retrospectively collected the clinical data of patients aged ≥65 years who underwent knee arthroplasty, total hip arthroplasty, or spinal surgery for lumbar or cervical degenerative disorders at our institution. The following data were evaluated: age, body mass index, sex, surgical site, prescription drugs used, American Society of Anesthesiologists physical status grade, and medical history, including hypertension, hyperlipidemia, diabetes, stroke, malignancy, and smoking. Polypharmacy was defined as the use of six or more drugs. RESULTS: In the present study, 767 consecutive patients were evaluated retrospectively. The prevalence of polypharmacy was >50% in the elderly patients with musculoskeletal disorders. The mean numbers of total drugs and pain relief medications were significantly higher in the lumbar surgery group than in the other surgery groups. Multivariable analysis revealed that the factors associated with polypharmacy were lumbar surgery, hypertension, hyperlipidemia, diabetes, and malignancy. CONCLUSIONS: This is the first study to cross-sectionally review the drugs prescribed to patients with degenerative musculoskeletal disorders. It clearly identified the factors associated with polypharmacy in elderly patients with degenerative musculoskeletal disorders. Particular attention should be paid to polypharmacy in elderly patients with lumbar degenerative disorders. Geriatr Gerontol Int 2022; 22: 121-126.

当院では2020年9月にROSA Knee(ROSA)を導入した。今回、ROSAの有用性を検証するため、2019年3月〜2021年6月に同一術者が変形性膝関節症に対しセメントレスTKAを行った92例をROSA使用群(50例)と非使用群(42例)に分け、手術時間やHip knee ankle(HKA)を比較した。手術時間はROSA使用群93.4±24.4分、非使用群66.3±15.1分で、使用群は有意に長かったが、約20例目からは90分以内となっていた。HKA(絶対値)はROSA使用群1.2±1.5°、非使用群2.3±2.3°であり、使用群が有意に良好であった。使用群における術前計画(予定サイズ)と実際のサイズの一致率は、大腿骨が32%、脛骨が68%で、大腿骨は1サイズダウンが多かった。

モジュラータイプのpersona trabecular metal tibia(PTMT)を用いて人工膝関節全置換術を行った19例(男3例、女16例)30関節を対象として、短期成績と脛骨ペグ孔内への骨充填法の有効性を検討した。手術時平均年齢は74.7±5.9歳、BMIは26.1±4.0kg/m2、原疾患は変形性膝関節症28関節、関節リウマチ2関節であった。膝可動域、日本整形外科学会膝関節機能スコア、単純X線から評価したコンポーネントの設置角度、アライメントからみた短期成績は良好であった。脛骨ペグ孔内への骨充填は12関節で行ったが、充填しなかった18関節に比べてペグ周囲の骨密度が高値であった。PTMTの使用は骨密度の上昇により初期固定力を高める効果が期待できるが、長期経過観察が必要であると考えられた。

BACKGROUND: Although the incidence of symptomatic pulmonary thromboembolism after elective surgery for degenerative musculoskeletal disorders is comparatively low, it is extremely detrimental to both patients and health-care providers. Therefore, its prevention is mandatory. We aimed to perform a cross-sectional analysis of deep venous thrombosis (DVT) before elective surgery for degenerative musculoskeletal disorders, including total knee arthroplasty (TKA), total hip arthroplasty (THA), and spinal surgery, and identify the factors associated with the incidence of preoperative DVT. METHODS: The clinical data of patients aged ≥ 30 years who underwent TKA or THA, and spine surgery for lumbar or cervical degenerative disorders at our institution were retrospectively collected. D-dimer levels were measured preoperatively in all the patients scheduled for surgery. For the patients with D-dimer levels ≥ 1 µg/mL or who were determined by their physicians to be at high risk of DVT, the lower extremity vein was preoperatively examined for DVT on ultrasonography. RESULTS: Overall, we retrospectively evaluated 1236 consecutive patients, including 701 men and 535 women. Of the patients, 431 and 805 had D-dimer levels ≥ 1 and < 1 µg/mL, respectively. Of 683 patients who underwent lower extremity ultrasonography, 92 had proximal (n = 7) and distal types (n = 85) of DVT. The preoperative prevalence of DVT was 7.4 %. No patient had the incidence of postoperative symptomatic venous thromboembolism. A multivariate analysis revealed that age ≥ 80 years (odds ratio [OR], 95 % confidence interval [CI]: 2.8, 1.1-7.3), knee surgery (2.1, 1.1-4.0), American Society of Anesthesiologists (ASA) grade 2 (2.8, 1.2-6.8), ASA grades 3 or 4 (3.1, 1.0-9.4), and malignancy (1.9, 1.1-3.2) were significantly associated with DVT incidence. CONCLUSIONS: This is the first study to conduct a cross-sectional analysis of preoperative DVT data of patients scheduled for elective surgery for degenerative musculoskeletal disorders. Although whether screening for preoperative DVT is needed to prevent postoperative symptomatic pulmonary thromboembolism remains to be clarified, our data suggested that DVT should be noted before surgery in the patients with advanced age, knee surgery, high ASA physical status, and malignancy.

79歳女性。Vancouver分類type B1ステム周囲骨折に対するプレート固定術から3年後に転倒し、左大腿部痛を主訴に当院へ受診となった。単純X線およびCT画像よりプレート先端に生じた大腿骨骨折(AO分類A1)と診断され、横止めEnder釘2本を用いて固定した。その結果、術後は疼痛なく良好に経過し、骨折前と同等のADLが得られた。

27歳男性。3歳時に両側Blount病と診断され、その後、両下肢の内反変形が進行し、8歳時に両側の脛骨外反骨切り術、9歳時に右のみの高位脛骨骨切り術(HTO)が行われた。更に13歳時には左脛骨内側顆部の挙上と同種骨移植が行われたが、24歳頃より左膝痛が出現した。今回、内反再発を認めたため、ドーム状骨切りとTriS medial HTOプレート固定を施行した結果、術後1年7ヵ月経過で左膝関節痛はなく、JOAスコアは術前の80点から術後90点へ改善した。

When sizing the femoral component or determining its placement in total knee arthroplasty (TKA), if the anterior-posterior diameter of the femoral condyle is between component sizes, the selected size will differ depending on whether anterior referencing (AR) or posterior referencing (PR) is used. As a result, the amount of resected bone will also vary. In the present prospective study, we compared the two referencing methods to determine which is more suitable for individual patients. We recruited 58 patients (92 joints) who received TKA using the standard technique with intermediate-size components. AR was used in 26 joints, and PR in 23 joints. Seventeen of the patients underwent same-day bilateral TKA in which components of different sizes were used for the left and right joints. AR resulted in significantly smaller anterior and posterior offsets than PR. Preoperative clinical evaluation revealed no significant differences among cases in which intermediate-size components were indicated, or those in which components of different sizes were indicated. When an intermediate-sized component was indicated using the AR method, moving the sizer forward resulted in a larger posterior gap, but this technique was nevertheless considered acceptable. AR is likely to be more suitable than PR as it achieves more physiological anterior clearance.

When sizing the femoral component or determining its placement in total knee arthroplasty (TKA), if the anterior–posterior diameter of the femoral condyle is between component sizes, the selected size will differ depending on whether anterior referencing (AR) or posterior referencing (PR) is used. As a result, the amount of resected bone will also vary. In the present prospective study, we compared the two referencing methods to determine which is more suitable for individual patients. We recruited 58 patients (92 joints) who received TKA using the standard technique with intermediate-size components. AR was used in 26 joints, and PR in 23 joints. Seventeen of the patients underwent same-day bilateral TKA in which components of different sizes were used for the left and right joints. AR resulted in significantly smaller anterior and posterior offsets than PR. Preoperative clinical evaluation revealed no significant differences among cases in which intermediate-size components were indicated, or those in which components of different sizes were indicated. When an intermediate-sized component was indicated using the AR method, moving the sizer forward resulted in a larger posterior gap, but this technique was nevertheless considered acceptable. AR is likely to be more suitable than PR as it achieves more physiological anterior clearance.

当院における人工膝関節置換術後のリハビリテーションは早期回復を目指して、術後2日目から自主トレーニング指導、ROMや筋力増強訓練を行い、状態に合わせて歩行訓練、階段昇降、ADL訓練を進めている。今回、歩行訓練の方法を中心に紹介し、2019年10月〜2020年1月に人工膝関節置換術を施行した28例32関節のリハビリ成績を報告した。32関節の内訳はTKAが24関節、単顆置換術が7関節、再置換術が1関節であった。入院日数は平均17±3.4日、リハビリ日数は全例14日、自宅退院率は57%であった。術前/退院時/術後1ヵ月時のROMは、伸展がそれぞれ-10.9±14.8°/-4.4±6.7°/-4.1±7.5°、屈曲がそれぞれ118.4±12.8°/103±11.7°/115.5±22.5°であった。術前と術後平均3.9週時の四頭筋力はそれぞれ201±86.8N/226.6±69.4Nであった。代表例としてTKAの1例を提示した。

62歳男性。37歳時に膝関節calcium pyrophosphate dihydrate deposition disease(CPPD症)の診断を受けていた。左膝は10年前に他院で高位脛骨骨切り術を受けていたが、徐々に両膝痛が悪化したため、手術目的で当科へ紹介となった。所見では糖尿病の合併、高度関節水腫や骨内側顆の骨破壊像が認められ、高度変形を伴った膝関節CPPD症(type F)と診断された。治療として両膝に骨移植・ステムエクステンションを併用したCR型TKAを施行した。その結果、術後4日で転倒にて左膝の膝蓋腱断裂を生じ追加手術を要したが、その後の経過は順調であった。目下、術後3年経過で移植骨は同化し、JOAスコアは両側とも90点と良好であった。

BACKGROUND: An accelerometer-based portable navigation system was recently introduced to improve prosthetic alignment during total knee arthroplasty (TKA). The purpose of this multicenter prospective randomized controlled trial (RCT) was to evaluate the effects of this accelerometer-based portable navigation system for achieving more accurate alignment during TKA in the clinical setting. METHODS: One hundred patients with primary varus osteoarthritis of the knee were enrolled in this prospective RCT conducted in 5 hospitals. A navigation system was utilized in 50 patients (navigation group), and a conventional intramedullary femoral guide and an extramedullary tibial guide were utilized in 50 patients (conventional group). At 6 months postoperatively, weight-bearing radiographs were obtained of the whole operative leg. An experienced surgeon who was blinded to the treatment assignments then measured the alignment to 1 decimal place with use of computer software. Power analysis showed that 41 knees were required in each group. RESULTS: There were no complications as a result of the use of the accelerometer-based portable navigation system. Postoperative radiographs were obtained in 45 patients from each group. There were no significant differences in sex, age, height, body weight, body mass index, preoperative femorotibial angle, and operative time between groups. The absolute differences of the femoral prosthesis (p = 0.01), tibial prosthesis (p < 0.01), and hip-knee-ankle angle (p < 0.01) from a neutral mechanical axis were less in the navigation group compared with those in the conventional group. Alignment outliers (>2° away from the neutral mechanical axis) of the tibial prosthesis and hip-knee-ankle angle were less in the navigation group (9% and 27%, respectively) compared with those in the conventional group (31% and 49%; p = 0.01 and p = 0.04, respectively). CONCLUSIONS: To our knowledge, this is the first multicenter prospective RCT to evaluate an accelerometer-based portable navigation system. An accelerometer-based portable navigation system provides more accurate prosthetic and limb alignment in the coronal plane than conventional techniques, without extended operative time or an increased rate of complications. The results of this study may help orthopaedic surgeons decide whether or not to use an accelerometer-based portable navigation system. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

51歳女性。既往として49歳時に毛髪鼻指節骨症候群I型と診断された。今回、右膝痛と右股関節痛、歩行障害を主訴に当科へ受診となった。右下肢単純X線およびMRI所見より右変形性膝関節症と診断され、ドーム状骨切りとTris medial HTOプレートを用いて高位脛骨骨切り術が施行された。その結果、骨癒合が得られ、術後1年4ヵ月で抜釘となり、術後2年の時点で右膝関節痛は消失し、自宅内では杖や歩行器による歩行が可能となった。

当科では感染TKAや化膿性膝関節炎の手術において、関節内の十分な掻爬および洗浄に加え、術後持続洗浄を行ってきたが、術後臥床を要するという難点があった。近年、抗菌薬含有骨セメント(ALAC)の抗菌薬徐放効果が明らかにされ、感染治療において持続洗浄を上回る有用性があると考えられる。そこで当科では、感染膝関節の掻爬後にバンコマイシン含有骨セメントを大腿骨遠位前面に貼付する手術を行い、その成績について検討した。対象は感染TKA 5例と化膿性膝関節炎3例で、成績は、感染TKA群のうち3例で感染鎮静化が得られたが、残る2膝は鎮静化が得られず、最終的に抜去・再置換となった。化膿性膝関節炎群では、1例が初回手術で鎮静化、1例が2回目の手術で鎮静化したが、残る1例は感染が遷延化している。

症例1は62歳男で、左足部痛が突然出現し、14時間後に高熱と左足部の発赤・腫脹が出現し救急搬送された。蜂窩織炎の診断で皮膚科に緊急入院し、入院7時間後に敗血症性ショックとなり、腫脹は大腿部まで拡大しLRINECスコア5点であった。入院14時間後にLRINECスコア8点となり、救命のため緊急に左大腿近位部切断を行った。症例2は53歳男で、発熱と右足部痛が突然出現し、13時間後に意識障害とショックバイタルで救急搬送され、壊死性筋膜炎の疑いで皮膚科に緊急入院した。入院時のLRINECスコアは5点で、右下腿〜足関節に軟部組織の腫脹があり、病巣掻爬術を計画した。しかし入院7時間後に状態が増悪し、救命のため緊急で右大腿切断を行った。両例とも入院時からショックバイタルであったがLRINECスコアは5点であったため術式の選択に迷いが生じた。結果として大腿切断により救命できたが、もっと早い段階で切断を考慮していれば、切断高位を下げADLの向上ができたと考えられた。