Patients › General-Health
体重、肥胖与关节健康
How body weight and obesity affect joint load, osteoarthritis, and the risks and outcomes of joint surgery — including the role of weight loss before an operation.
什么是体重与关节健康¶
体重与关节健康密切相关。体重超标会让更多负荷通过您的关节,尤其是膝关节内侧。这有助于解释为什么在肥胖人群中,膝关节内侧的磨损性关节炎(骨关节炎)很常见 [1]。多余的体重还会影响您的全身,而不仅仅是关节。肥胖是一种会在全身引发炎症的疾病,而这种炎症也会波及您的关节 [2]。
本页面适合所有体重超标并有关节疼痛的人,或正在考虑关节手术的人。它也适合家长阅读,因为儿童肥胖是一种可以改变的状况,加以干预可以改善孩子的关节健康和整体健康 [3]。好消息是,体重是您可以采取行动加以改变的因素之一。减重可以缓解关节症状,并降低手术相关的某些风险。
多余的体重主要通过两种方式影响关节。第一种是机械性的:每走一步,通过关节的负荷都会更大。第二种是化学性的:肥胖带来的炎症会磨损关节内部的光滑表面,而在患有肥胖的成年人中,这层表面可能无法很好地适应更高的负荷 [4]。另一方面,体重过轻也有风险,其中一些与肥胖相关的风险相重叠 [5]。
体重与手术之间的关联是双向的。超重或肥胖的人往往比体重正常的人在更年轻时就需要进行髋关节和膝关节置换 [6]。但多余的体重并不意味着不能手术。一项观察髋关节置换术后十年结果的研究发现,没有理由仅凭 BMI 就限制患者接受手术 [7]。处理好其他健康问题并仔细规划手术,可以获得与 BMI 正常的患者相近的效果 [8]。
它有效吗?¶
坦白地说,证据不一,而且其中一些证据还很薄弱。减重可以缓解关节症状,并降低手术相关的某些风险。这一总体结论是站得住脚的。但当研究人员仔细研究具体的手术时,情况就不那么明确了。
对于髋关节和膝关节置换,在某些手术中,多余的体重会增加需要再次进行修复手术的可能性。研究发现,肥胖人群在部分膝关节置换术后的翻修率更高 [9],因骨折而进行的反式肩关节置换术后的翻修率也更高 [10]。对于髋关节置换,一项研究发现,肥胖分级与再次手术的风险、创伤程度或时间无关 [11]。诸如此类的结果并不都指向同一方向,而且许多研究规模较小或随访时间较短。
有些发现简单来说是令人安心的。在髋关节镜(微创)手术后,肥胖人群在疼痛和功能方面获得的长期改善,与体重正常的人相当 [12]。在腕部骨折手术后,一项研究发现,体重正常者与肥胖者之间的关节活动度没有差异 [13]。另一方面,膝关节镜(微创)手术在肥胖人群中的效果往往较差,尤其是在已经存在关节炎的情况下 [14]。
此外也存在空白。对于 BMI 为 45 或以上的人,针对某一类膝关节置换的研究规模太小,无法得出确切结论 [15]。对于某些手术选择,现有数据太弱,无法支持任何一方面的明确指导 [16]。
对您而言,要点如下。多余的体重会改变关节手术相关的某些风险,但并不意味着不能手术,许多肥胖人群在手术后恢复良好。您的医生可以与您讨论这些发现中哪些适用于您的关节和您的情况。
风险有哪些?¶
关节手术最可能出现的风险,是您在术后最初几天和几周内会注意到的那些:伤口问题、僵硬以及恢复较慢。多余的体重可能使其中一些问题更容易发生。在手臂和手部骨折手术后,肥胖人群在最初 90 天内以及 2 年时的并发症发生率都更高 [17]。在 2 年时,这些并发症包括骨骼在错误的位置愈合、骨骼未能愈合,以及需要再次手术 [17]。
有些风险取决于具体的关节和手术。在部分膝关节置换术后,肥胖人群更常需要进行修复手术 [9]。因骨折而进行的反式肩关节置换术后也是如此,多余的体重与总体修复手术更多以及关节脱出原位(脱位)的问题更多有关 [10]。在某一类机器人辅助膝关节置换中,肥胖仍然是假体松动或发生机械性失效的一个风险因素 [18]。
并非所有风险都指向同一方向,有些发现确实结论不一。在另一项关于机器人辅助膝关节置换的研究中,严重肥胖(BMI 35 或以上)人群并发症较多的趋势在统计学上并不明确 [19]。膝关节置换术后僵硬是一个已知的担忧,但一项研究发现,在接受松解僵硬膝关节的操作后,较高的体重与更多僵硬或更差的结果并无关联 [20]。体重过轻同样存在风险,其中一些与肥胖的风险相重叠 [5]。
对于目前已知的情况,也确实存在空白。对于 BMI 为 45 或以上的人,针对某一类膝关节置换的研究规模太小,无法就安全性得出确切结论 [15]。对于下肢骨折的儿童,肥胖意味着住院时间更长,以及出现更多家属不希望的出院安排 [21]。
总体情况是这样的。多余的体重会增加手术相关的某些风险,但并不意味着不能手术,而且通过处理好其他健康问题并仔细规划手术,其中许多风险是可以降低的 [8]。您的医生可以与您讨论其中哪些适用于您。
这适合您吗?¶
如果您体重超标并有关节疼痛,本页面正是为您而写的。多余的体重并不意味着不能手术。许多肥胖人群在髋关节和膝关节置换术后恢复良好,尤其是在其他健康问题得到控制、手术经过仔细规划的情况下 [8]。在手术前减重可以缓解关节症状,并降低手术相关的某些风险。
手术并不是唯一的途径。对于某些关节和某些手术,多余的体重会增加日后需要进行修复手术的可能性 [9]。您的医生可以与您一起比较各种选择,包括运动和体重管理等非手术治疗,并帮助您权衡每种选择能带来什么。
这是一个共同作出的决定。您带来的是您的目标、您的疼痛和您的日常生活。您的医生带来的是关于您的关节和您的情况的证据。您和医生可以共同决定适合您的治疗时机和治疗方式。
核心要点¶
体重超标会影响您的关节以及手术相关的某些风险,但并不意味着不能手术。减重可以缓解关节症状并降低其中一些风险,值得作为您治疗方案的一部分,与运动和其他治疗一起考虑。现实的期望是稳步改善,而不是速效解决,因为效果因人而异。最重要的提醒是,关于具体手术的证据结论不一,因此请与您的医生讨论哪些发现适用于您的关节和您的情况。
参考文献¶
[1] Cartilage contact characteristics of the knee during gait in individuals with obesity. Journal of Orthopaedic Research. 2022. DOI: 10.1002/jor.25288
[2] Reframing Obesity in Knee Osteoarthritis: A Call for a Transdisciplinary Approach Beyond Biomechanics. Arthroscopy. 2026. DOI: 10.1002/arj.70051
[3] The Role of Obesity in Pediatric Orthopedics. JAAOS: Global Research and Reviews. 2019. DOI: 10.5435/jaaosglobal-d-19-00036
[4] Body mass index moderates the association between gait kinetics, body composition, and femoral knee cartilage characteristics. Journal of Orthopaedic Research. 2020. DOI: 10.1002/jor.24655
[5] Weight on the fixation: the influence of body mass index on lower extremity fracture fixation outcomes. Injury. 2025. DOI: 10.1016/j.injury.2025.112864
[6] Overweight and Obese Patients Require Total Hip and Total Knee Arthroplasty at a Younger Age. Journal of Orthopaedic Research. 2019. DOI: 10.1002/jor.24460
[7] Do the Ten-Year Functional Outcomes and Revision Rates of Total Hip Arthroplasty in Obese and Morbidly Obese Patients Justify Restricting Their Access to Surgery?. The Journal of Arthroplasty. 2026. DOI: 10.1016/j.arth.2025.07.044
[8] Body Mass Index > 40 Is Not Correlated With Early Complications in Patients Undergoing Primary Total Joint Arthroplasty at an Ambulatory Surgical Center. The Journal of Arthroplasty. 2026. DOI: 10.1016/j.arth.2025.08.065
[9] Obesity is Associated with Higher Rates of Revision Following Unicompartmental Knee Arthroplasty. Orthopaedic Journal of Sports Medicine. 2026. DOI: 10.1177/2325967125s00336
[10] Revision rates between obese and nonobese total shoulder arthroplasty patients: an Australian registry data study. Journal of Shoulder and Elbow Surgery. 2026. DOI: 10.1016/j.jse.2025.05.036
[11] Obesity Class Does Not Associate With Incidence, Timing, or Invasiveness of Reoperations After Total Hip Arthroplasty. The Journal of Arthroplasty. 2026. DOI: 10.1016/j.arth.2025.07.026
[12] Obese Patients Treated by Hip Arthroscopy for Femoroacetabular Impingement Syndrome — 10-Year Functional Outcomes and Conversion Rates to Arthroplasty Compared With Normal-Weight Patients. The American Journal of Sports Medicine. 2026. DOI: 10.1177/03635465251392585
[13] Influence of body mass index on health-related quality of life after surgical treatment of intra-articular distal radius fractures. A retrospective 7-year follow-up study. Hand Surgery and Rehabilitation. 2019. DOI: 10.1016/j.hansur.2019.09.004
[14] Editorial Commentary: Obesity and Osteoarthritis Are Risk Factors for Conversion to Arthroplasty, With or Without Previous Knee Arthroscopic Surgery. Arthroscopy. 2025. DOI: 10.1016/j.arthro.2025.04.036
[15] Body Mass Index of 45 Is a Safe Cut-Off for Cementless Total Knee Arthroplasty. The Journal of Arthroplasty. 2025. DOI: 10.1016/j.arth.2025.12.038
[16] Reply to: "Letter to the Editor Commenting on: 'Current Evidence Does Not Support the Use of Tibial Stem Extension in Total Knee Arthroplasty of Obese Patients: A Systematic Review'". The Journal of Arthroplasty. 2026. DOI: 10.1016/j.arth.2025.11.056
[17] Obesity is associated with higher 90-day and 2-year complication rates following surgical fixation of upper extremity fractures: A nationwide analysis. Injury. 2025. DOI: 10.1016/j.injury.2025.112891
[18] Impact of high body mass index on functionally aligned image-based robotic total knee arthroplasty: Comparable functional outcomes but higher mechanical failures. Journal of ISAKOS. 2025. DOI: 10.1016/j.jisako.2025.100861
[19] Impact of body mass index on robotic-assisted total knee arthroplasty outcomes: A retrospective cohort analysis. Journal of ISAKOS. 2025. DOI: 10.1016/j.jisako.2025.100927
[20] Obesity Severity and Stiffness After Total Knee Arthroplasty Revisited: A Contemporary Analysis of Patients Requiring Manipulation Under Anesthesia. The Journal of Arthroplasty. 2026. DOI: 10.1016/j.arth.2026.03.080
[21] Impact of pediatric obesity on surgical outcomes of lower extremity fractures: a nationwide analysis (2010–2019). BMC Musculoskeletal Disorders. 2026. DOI: 10.1186/s12891-025-09349-6
Evidence & references
This is the clinical evidence summary written for health professionals. It is technical, and it lists the research this page was built from. You do not need to read it to understand your treatment or to make a decision about it.
Overview¶
- Obesity is a modifiable condition, and addressing it can improve the orthopaedic and overall health of children [1].
- Obesity is a systemic disease with profound inflammatory consequences on joint health, extending beyond mechanical burden [11].
- There is significant confusion regarding the relationship between energy intake, energy expenditure, and obesity, with greater attention historically focused on diet than physical inactivity [5].
- Physical activity equivalent to approximately 30–35 minutes of vigorous intensity per week appears to offset the association between abdominal obesity and incident cardiovascular disease [10].
- Each 1-unit increase in body mass index is associated with a 9% reduction in osteoporosis risk [2].
- Obesity affects knee cartilage contact location primarily in the medial compartment, which explains part of the high prevalence of medial knee osteoarthritis in the obese population [17].
- Increased CDC weight category is associated with worsening clinical outcomes across all measures following meniscus repair in pediatric and adolescent populations [8].
- Increased body mass index among patients with total joint replacement is associated with decreased ambulatory activity [13].
- Overweight and obese patients require total hip and total knee arthroplasty at a significantly younger age than normal-weight patients [18].
- Obese and overweight patients convert to total hip arthroplasty at significantly higher rates compared with normal-weight patients following hip arthroscopy for femoroacetabular impingement syndrome [22].
- Underweight patients demonstrate an elevated risk for complications that overlap with those seen in obese patients following lower extremity fracture fixation, yet experience lower rates of other complications [6].
- In a cohort of obese patients undergoing total hip arthroplasty, WHO obesity class was not associated with the risk, invasiveness, or timing of reoperations [21].
- Ten-year functional outcomes and revision rates of total hip arthroplasty do not justify restricting access to surgery on the basis of body mass index [51].
- Increasing obesity severity is not associated with higher rates of postoperative stiffness or inferior outcomes following manipulation under anesthesia after total knee arthroplasty [12].
- Focusing on management of preoperative comorbidities and custom surgical planning can achieve outcomes comparable to those of patients with normal body mass index in ambulatory surgical centers, questioning body mass index as an exclusion criterion for primary total joint arthroplasty [3].
- Current evidence does not support the routine use of tibial stem extensions in obese total knee arthroplasty patients due to insufficient, heterogeneous, and very low certainty data, though specific designs may benefit selected populations [15].
- The absence of direct comparative studies precludes causal inference regarding the role of weight-bearing timing in medial meniscus posterior root tear repair [7].
- Mortality did not decrease in association with increasing body mass index in isolated blunt abdominal trauma, as this may be offset by the increase in co-morbidities in this population [4].
- The Arthritis Committee recognizes the profound importance of arthritic disorders to the general population, not only as a health problem, but for their social and economic impact [25].
- Both the individual and the physician have many options from which to choose when selecting an appropriate weight loss program [14].
How It Works¶
Systemic and Metabolic Mechanisms¶
- Obesity is a systemic disease with profound inflammatory consequences on joint health [11].
- Obesity promotes lipid accumulation in mouse cartilage via acetyl-CoA carboxylase (ACC) mediated chondrocyte de novo lipogenesis [41].
- Inhibition of ACC ameliorates lipid accumulation in chondrocytes, suggesting ACC could be targeted to treat obesity-associated osteoarthritis [41].
- Diet-induced obesity alters bone morphology and mineral density in a manner dependent on dietary free fatty acid content [40].
- Adolescent murine obesity alters structural, mechanical, and compositional properties of bone, which may have lasting implications on bone health even after obesity is corrected [36].
- There is confusion regarding the relation of energy intake and energy expenditure to obesity, with more attention focused on diet than physical inactivity [5].
- An aggregate exercise programme energy expenditure greater than 10,000 kcal may be required to promote reductions in intrahepatic fat [20].
- When combined with liraglutide treatment, exercise results in a more holistic state of health that may enhance adherence and promote longer-term weight-loss maintenance [19].
Biomechanical and Cartilage Effects¶
- Obesity affects knee cartilage contact location mainly in the medial compartment, explaining part of the high prevalence of medial knee osteoarthritis in the obese population [17].
- Articular cartilage may not adapt to higher joint loads in adults with obesity [39].
- Aging and obesity are associated with a loss of the positive relationship between cartilage thickness and ambulatory loads [23].
- Under weight-bearing conditions, patellofemoral joint contact areas increased by an average of 24% [43].
- Obesity did not enhance cartilage degeneration in the absence of fracture or surgical trauma [34].
Clinical Outcomes and Complications¶
- Each 1-unit increase in BMI is associated with a 9% reduction in osteoporosis risk [2].
- Following medial meniscus posterior root tear repair, osteoarthritis progression occurs at higher rates with elevated BMI [38].
- Obese patients demonstrate increased risks of malunion, nonunion, and revision at 2 years following surgical fixation of upper extremity fractures [26].
- Underweight patients demonstrate an elevated risk for complications that overlap with those seen in obese patients following lower extremity fracture fixation [6].
- Obesity remains a critical risk factor for mechanical failures in functionally aligned image-based robotic total knee arthroplasty [28].
- A nonsignificant trend toward a higher complication rate was observed in patients with severe obesity (BMI ≥35 kg/m2) undergoing robotic-assisted total knee arthroplasty [42].
- A statistically significant increase in arthrofibrosis was found in patients with BMI <25 kg/m2 undergoing robotic-assisted total knee arthroplasty [42].
- Modern surgical practices and implant designs may have mitigated traditional obesity-related risks regarding loosening and mechanical failure in total knee arthroplasty [24].
- Increasing obesity severity is not associated with higher rates of postoperative stiffness or inferior outcomes following manipulation under anesthesia for total knee arthroplasty [12].
- Focusing on management of preoperative comorbidities and custom surgical planning can achieve outcomes comparable to those of patients with normal BMIs at ambulatory surgical centers for primary total joint arthroplasty [3].
- Body mass index has a weak-to-moderate association with peri-incisional adiposity in primary total joint arthroplasty patients [27].
- The soft tissue-to-bone ratio reflects local anatomical factors that directly influence surgical exposure and wound healing, unlike BMI [35].
- No significant differences were observed between above-average and below-average BMI groups regarding clinical improvements following arthroscopically assisted posterior latissimus dorsi tendon transfer [16].
Trauma and Mortality¶
- Mortality did not decrease in association with increasing BMI in isolated blunt abdominal trauma, potentially offset by increased co-morbidities [4].
- The "Obesity Paradox" in major trauma is explained by biomechanical protection resulting in a lower Injury Severity Score, which neutralizes the increased physiological and comorbidity burden of the obese state [37].
Modifiability and Management¶
- Obesity is modifiable, and addressing the issue can improve the orthopaedic and overall health of children [1].
- Both individuals and physicians have many options from which to choose when selecting an appropriate weight loss program [14].
What the Evidence Shows¶
Pediatric Orthopedics¶
- Increased CDC weight category is associated with worsening clinical outcomes across all measures in pediatric and adolescent populations following meniscus repair [8].
- Pediatric obesity substantially lengthened length of stay and encouraged undesirable discharge when compared to non-obese individuals in lower extremity fracture cases [32].
Bone Density and Systemic Effects¶
- Each 1-unit increase in BMI was associated with a 9% reduction in osteoporosis risk based on a dose–response analysis of nine studies [2].
- Obesity is more than a mechanical burden on the knee; it is a systemic disease with profound inflammatory consequences on joint health [11].
Total Joint Arthroplasty: Knee¶
- Focusing on management of preoperative comorbidities and custom surgical planning can achieve outcomes comparable to those of patients who have normal BMIs at ambulatory surgical centers for primary total knee arthroplasty, questioning BMI as an exclusion criterion [3].
- Increasing obesity severity is not associated with higher rates of postoperative stiffness or inferior outcomes following manipulation under anesthesia, and concern for stiffness alone should not serve as a categorical barrier to total knee arthroplasty or manipulation under anesthesia when clinically indicated [12].
- Obesity remains a critical risk factor for mechanical failures in functionally aligned image-based robotic total knee arthroplasty, despite comparable functional outcomes [28].
- Obese patients are at increased risk of higher rate of revision following unicompartmental knee arthroplasty based on AOANJRR data [33].
- Total weight loss percentage was higher in bariatric surgery patients (28.7%, P < 0.001) compared to immediate total knee arthroplasty in patients with severe obesity and advanced knee osteoarthritis [47].
- The numbers were too small to draw conclusions in patients who have a BMI ≥ 45 regarding the safety of cementless total knee arthroplasty [9].
Total Joint Arthroplasty: Hip¶
- In a cohort of obese patients who underwent total hip arthroplasty, the WHO obesity class was not associated with risk, invasiveness, or timing of reoperations [21].
- In morbidly obese patients, dual mobility implants demonstrated excellent five-year survivorship with outcomes comparable or slightly superior to fixed-bearing constructs [44].
- Semaglutide appears to be a safe alternative to bariatric surgery for weight management before total hip arthroplasty, with similar implant survival and postoperative complication rates [30].
Total Joint Arthroplasty: Shoulder¶
- Obesity has an increased risk of all-cause revisions and revision for instability or dislocation in patients receiving reverse total shoulder arthroplasty indicated for fractures [29].
Arthroscopy and Soft Tissue¶
- Obese and overweight patients converted to total hip arthroplasty at significantly higher rates compared with normal-weight patients following hip arthroscopy for femoroacetabular impingement syndrome [22].
- Hip arthroscopy for the treatment of femoroacetabular impingement and labral tears in patients with obesity yielded significant and sustainable long-term improvements, which were equivalent to those of a benchmark matched control group of normal-weight patients [45].
- No significant differences were observed between above-average and below-average BMI groups, and BMI was not correlated with clinical improvements following arthroscopically assisted posterior latissimus dorsi tendon transfer for irreparable posterosuperior rotator cuff tears [16].
- Obesity and preexisting osteoarthritis are known risk factors for predicting poor outcomes and conversion to arthroplasty after knee arthroscopy, but the study lacks a control group and specific procedural details to determine if the surgery itself drives progression versus patient factors [50].
Fracture Fixation and Trauma¶
- Underweight patients demonstrated an elevated risk for complications that overlapped with those seen in obese patients, yet experienced lower rates of others, in lower extremity fracture fixation [6].
- At 2 years, obese patients demonstrated increased risks of malunion, nonunion, and revision following surgical fixation of upper extremity fractures [26].
- Mortality did not decrease in association with increasing BMI in isolated blunt abdominal trauma, as this may be offset by the increase in co-morbidities in this population [4].
Patient Selection and Preoperative Factors¶
- BMI has a weak-to-moderate association with peri-incisional adiposity in primary total joint arthroplasty patients [27].
- Women had decreased odds of losing greater than five pounds before surgery despite increased odds of having preoperative bariatric surgery [31].
- Increased body mass index among patients with a total joint replacement is associated with decreased ambulatory activity [13].
Weight Management and Lifestyle¶
- There is enormous confusion about the relation of energy intake and energy expenditure to obesity, with much more attention focused on diet and obesity than on physical inactivity and obesity [5].
- Physical activity equivalent to approximately 30–35 min of vigorous intensity per week appears to offset the association between abdominal obesity and incident cardiovascular disease [10].
- When combined with liraglutide treatment, exercise results in a more holistic state of health that may result in improved longer-term health and may enhance adherence to the treatment and promote longer-term weight-loss maintenance [19].
- An aggregate exercise programme energy expenditure (>10 000 kcal) may be required to promote reductions in intrahepatic fat in adults who are overweight or exhibit fatty liver disease [20].
- Women with high-intensity interval training had significant reduction in their weight and BMI compared to those who followed moderate-intensity continuous training protocol in post-bariatric surgery patients with sarcopenic obesity [48].
Practical Considerations¶
Preoperative Management and Weight Loss¶
- Obesity is a modifiable condition, and addressing it can improve orthopaedic and overall health in children [1].
- There is significant confusion regarding the relationship between energy intake, energy expenditure, and obesity, with greater attention focused on diet than on physical inactivity [5].
- Both individuals and physicians have multiple options available when selecting an appropriate weight loss program [14].
- When combined with liraglutide treatment, exercise results in a more holistic state of health that may improve longer-term health, enhance treatment adherence, and promote longer-term weight-loss maintenance [19].
Arthroplasty Outcomes and Complications¶
- Focusing on management of preoperative comorbidities and custom surgical planning can achieve outcomes comparable to those of patients with normal BMIs at ambulatory surgical centers, questioning BMI as an exclusion criterion [3].
- The numbers in the study were too small to draw conclusions in patients who have a BMI ≥ 45 regarding cementless total knee arthroplasty [9].
- Increasing obesity severity is not associated with higher rates of postoperative stiffness or inferior outcomes following manipulation under anesthesia, and concern for stiffness alone should not serve as a categorical barrier to TKA or MUA when clinically indicated [12].
- Obesity is associated with higher rates of revision following unicompartmental knee arthroplasty based on AOANJRR data [33].
- Overweight and obese patients require total hip and total knee arthroplasty at a significantly younger age compared to normal-weight patients [18].
Fracture and Trauma Outcomes¶
- Underweight patients demonstrated an elevated risk for complications that overlapped with those seen in obese patients, yet experienced lower rates of other complications in lower extremity fracture fixation [6].
- Obesity substantially lengthened length of stay and encouraged undesirable discharge when compared to non-obese individuals in pediatric lower extremity fractures [32].
Joint Health and Biomechanics¶
- Obesity is a systemic disease with profound inflammatory consequences on joint health, extending beyond a mechanical burden on the knee [11].
- Obesity affects the contact location mainly in the medial compartment of the knee, which explains, in part, the high prevalence of medial knee osteoarthritis in the obese population [17].
- Aging and obesity are both associated with a loss of the positive relationship between cartilage thickness and ambulatory loads, and this relationship is dependent on the compartment and whether the load is generated by body size or subject-specific gait mechanics [23].
Soft Tissue and Arthroscopic Outcomes¶
- The absence of direct comparative studies precludes causal inference regarding the role of weight-bearing timing in medial meniscus posterior root tears repair [7].
Key Evidence¶
- [L5] Obesity is modifiable, and addressing the issue can improve the orthopaedic and overall health of children. [1] (10.5435/jaaosglobal-d-19-00036)
- [L1] Based on our dose–response analysis of nine studies, each 1-unit increase in BMI was associated with a 9% reduction in osteoporosis risk. [2] (10.1186/s12891-026-09675-3)
- [L3] Focusing on management of preoperative comorbidities and custom surgical planning can achieve outcomes comparable to those of patients who have normal BMIs at ASCs, questioning BMI as an exclusion criterion and advocating for more inclusive, evidence-based patient selection. [3] (10.1016/j.arth.2025.08.065)
- [L3] Mortality did not decrease in association with increasing BMI, as this may be offset by the increase in co-morbidities in this population. [4] (10.1016/j.injury.2024.111612)
- [L5] There is enormous confusion about the relation of energy intake and energy expenditure to obesity, with much more attention focused on diet and obesity than on physical inactivity and obesity. [5] (10.1136/bjsports-2015-094911)
- [L3] Underweight patients demonstrated an elevated risk for complications that overlapped with those seen in obese patients, yet experienced lower rates of others. [6] (10.1016/j.injury.2025.112864)
- [L4] However, the absence of direct comparative studies precludes causal inference regarding the role of weight-bearing timing. [7] (10.1002/arj.70529)
- [L3] Increased CDC weight category is associated with worsening clinical outcomes across all measures. [8] (10.1016/j.injury.2026.113122)
- [L3] However, the numbers were too small to draw conclusions in patients who have a BMI ≥ 45. [9] (10.1016/j.arth.2025.12.038)
- [L3] Physical activity equivalent to approximately 30–35 min of vigorous intensity per week appears to offset the association between abdominal obesity and incident CVD. [10] (10.1136/bjsports-2023-107252)
- [L5] Obesity is more than a mechanical burden on the knee; it is a systemic disease with profound inflammatory consequences on joint health. [11] (10.1002/arj.70051)
- [L3] These findings suggest that increasing obesity severity is not associated with higher rates of postoperative stiffness or inferior outcomes following MUA and that concern for stiffness alone should not serve as a categorical barrier to TKA or MUA when clinically indicated. [12] (10.1016/j.arth.2026.03.080)
- [L4] We therefore conclude that increased body mass index (greater obesity) among patients with a total joint replacement is associated with decreased ambulatory activity. [13] (10.1002/jor.1100180106)
- [Paper] Both the individual and the physician have many options from which to choose when selecting an appropriate weight loss program. [14] (10.1016/s0278-5919(05)70176-9)
- [L5] The authors conclude that current evidence does not support the routine use of tibial stem extensions in obese total knee arthroplasty patients due to insufficient, heterogeneous, and very low certainty data, though specific designs may benefit selected populations. [15] (10.1016/j.arth.2025.11.056)
- [L2] No significant differences were observed between above-average and below-average BMI groups, and BMI was not correlated with clinical improvements. [16] (10.1016/j.xrrt.2025.100634)
- [L4] These findings suggest that obesity affects the contact location mainly in the medial compartment, which explains, in part, the high prevalence of medial knee OA in the obese population. [17] (10.1002/jor.25288)
- [L3] This is the first study to demonstrate the significantly earlier age at which THA and TKA are required for overweight patients and those in obese category 1, in addition to those in obesity categories 2 and 3. [18] (10.1002/jor.24460)
- [Paper] It is clear that, when combined with liraglutide treatment, exercise results in a more holistic state of health that may result in improved longer-term health and may enhance adherence to the treatment and promote longer-term weight-loss maintenance. [19] (10.1136/bjsports-2021-104754)
- [L1] An aggregate exercise programme energy expenditure (>10 000 kcal) may be required to promote reductions in intrahepatic fat. [20] (10.1136/bjsports-2016-096197)
- [L3] In this cohort of obese patients who underwent THA, the WHO obesity class was not associated with risk, invasiveness, or timing of reoperations. [21] (10.1016/j.arth.2025.07.026)
- [L3] Obese and overweight patients converted to THA at significantly higher rates compared with normal-weight patients. [22] (10.1177/03635465251400355)
- [L4] These results suggest that aging and obesity are both associated with a loss of the positive relationship between cartilage thickness and ambulatory loads, and that the relationship is dependent on the compartment and whether the load is generated by body size or subject-specific gait mechanics. [23] (10.1002/jor.22530)
- [L3] These findings suggest modern surgical practices and implant designs may have mitigated traditional obesity-related risks. [24] (10.1016/j.arth.2026.04.031)
- [Paper] The Arthritis Committee recognizes the profound importance of arthritic disorders to the general population, not only as a health problem, but for their social and economic impact. [25] (10.1016/s0363-5023(83)80245-7)
- [L3] At 2 years, obese patients demonstrated increased risks of malunion, nonunion, and revision. [26] (10.1016/j.injury.2025.112891)
- [L3] BMI has a weak-to-moderate association with peri-incisional adiposity in primary total joint arthroplasty patients. [27] (10.1016/j.arth.2024.08.020)
- [L3] However, obesity remains a critical risk factor for mechanical failures. [28] (10.1016/j.jisako.2025.100861)
- [L3] Obesity has an increased risk of all-cause revisions and revision for instability or dislocation in patients receiving rTSA indicated for fractures. [29] (10.1016/j.jse.2025.05.036)
- [L3] Semaglutide appears to be a safe alternative to bariatric surgery for weight management before THA, with similar implant survival and postoperative complication rates. [30] (10.1016/j.arth.2025.08.068)
- [L3] Women had decreased odds of losing greater than five pounds before surgery despite increased odds of having preoperative bariatric surgery. [31] (10.1016/j.arth.2026.06.021)
- [L4] Obesity substantially lengthened length of stay and encouraged undesirable discharge when compared to non-obese individuals. [32] (10.1186/s12891-025-09349-6)
- [L3] Based on AOANJRR data, obese patients are at increased risk of higher rate of revision following UKA. [33] (10.1177/2325967125s00336)
- [Paper] Obesity did not enhance cartilage degeneration in the absence of fracture or surgical trauma. [34] (10.1002/jor.24799)
- [L3] Unlike BMI, the STiB ratio reflects local anatomical factors that directly influence surgical exposure and wound healing. [35] (10.1016/j.arth.2025.09.022)
- [Paper] Adolescent murine obesity alters structural, mechanical and compositional properties of the bone, which may have lasting implication on bone health even after the obesity is corrected. [36] (10.1002/jor.25378)
- [L3] Our findings strongly suggest that the "Obesity Paradox" in major trauma is not a mere statistical anomaly, but a reproducible phenomenon with a distinct mechanistic explanation: Biomechanical protection, which results in a lower ISS, neutralizes the increased physiological and comorbidity burden of the obese state. [37] (10.1016/j.injury.2025.112913)
- [L1] Following MMPRT repair, repairs show progression of osteoarthritis with higher rates seen with elevated BMI. [38] (10.1002/arj.70028)
- [L4] These findings suggest that articular cartilage may not adapt to higher joint loads in adults with obesity. [39] (10.1002/jor.24655)
- [Paper] Diet-induced obesity significantly altered bone morphology and mineral density in a manner that was dependent on dietary free fatty acid content. [40] (10.1002/jor.24219)
- [Paper] This was supported by the observation that ACC inhibition ameliorated lipid accumulation in chondrocytes, thereby suggesting that ACC could potentially be targeted to treat obesity-associated OA. [41] (10.1002/jor.25322)
- [L2] However, a nonsignificant trend toward a higher complication rate was observed in patients with severe obesity (BMI ≥35 kg/m2), while a statistically significant increase in arthrofibrosis was found in patients with BMI <25 kg/m2. [42] (10.1016/j.jisako.2025.100927)
- [L4] Under weight-bearing conditions, contact areas increased by an average of 24% (p < 0.05). [43] (10.1016/j.orthres.2004.08.003)
- [L3] In morbidly obese patients, DM implants demonstrated excellent five-year survivorship with outcomes comparable or slightly superior to fixed-bearing constructs. [44] (10.1016/j.arth.2026.03.075)
- [L3] Hip arthroscopy for the treatment of FAI and labral tears in patients with obesity yielded significant and sustainable long-term improvements, which were equivalent to those of a benchmark matched control group of normal-weight patients. [45] (10.1177/03635465251392585)
- [L1] Total weight loss % was higher in bariatric surgery patients (28.7%, P < 0.001). [47] (10.1016/j.arth.2026.05.033)
- [L1] Additionally, women with HIIT training had significant reduction in their weight and BMI compared to those who followed MICT training protocol. [48] (10.1186/s12891-026-09722-z)
- [L5] Obesity and preexisting osteoarthritis are known risk factors for predicting poor outcomes and conversion to arthroplasty after knee arthroscopy, but the study lacks a control group and specific procedural details to determine if the surgery itself drives progression versus patient factors. [50] (10.1016/j.arthro.2025.04.036)
- [L3] The ten-year functional outcomes and revision rates of THA do not justify restricting access to surgery on the basis of BMI. [51] (10.1016/j.arth.2025.07.044)
References¶
[1] The Role of Obesity in Pediatric Orthopedics. JAAOS: Global Research and Reviews. 2019. DOI: 10.5435/jaaosglobal-d-19-00036
[2] The association between body mass index and osteoporosis, with consideration of sex differences: a systematic review and dose-response meta-analysis. BMC Musculoskeletal Disorders. 2026. DOI: 10.1186/s12891-026-09675-3
[3] Body Mass Index > 40 Is Not Correlated With Early Complications in Patients Undergoing Primary Total Joint Arthroplasty at an Ambulatory Surgical Center. The Journal of Arthroplasty. 2026. DOI: 10.1016/j.arth.2025.08.065
[4] An evaluation of the “Obesity Paradox” in isolated blunt abdominal trauma in the United States. Injury. 2024. DOI: 10.1016/j.injury.2024.111612
[5] It is time to bust the myth of physical inactivity and obesity: you cannot outrun a bad diet. British Journal of Sports Medicine. 2015. DOI: 10.1136/bjsports-2015-094911
[6] Weight on the fixation: the influence of body mass index on lower extremity fracture fixation outcomes. Injury. 2025. DOI: 10.1016/j.injury.2025.112864
[7] Suboptimal Clinical and Radiologic Outcomes After Medial Meniscus Posterior Root Tears Repair With Early Partial Weight‐Bearing: A Systematic Review. Arthroscopy. 2026. DOI: 10.1002/arj.70529
[8] Increased weight and BMI are associated with increased failure following meniscus repair in the pediatric and adolescent populations. Injury. 2026. DOI: 10.1016/j.injury.2026.113122
[9] Body Mass Index of 45 Is a Safe Cut-Off for Cementless Total Knee Arthroplasty. The Journal of Arthroplasty. 2025. DOI: 10.1016/j.arth.2025.12.038
[10] Joint associations of device-measured physical activity and abdominal obesity with incident cardiovascular disease: a prospective cohort study. British Journal of Sports Medicine. 2023. DOI: 10.1136/bjsports-2023-107252
[11] Reframing Obesity in Knee Osteoarthritis: A Call for a Transdisciplinary Approach Beyond Biomechanics. Arthroscopy. 2026. DOI: 10.1002/arj.70051
[12] Obesity Severity and Stiffness After Total Knee Arthroplasty Revisited: A Contemporary Analysis of Patients Requiring Manipulation Under Anesthesia. The Journal of Arthroplasty. 2026. DOI: 10.1016/j.arth.2026.03.080
[13] Relationship between body mass index and activity in hip or knee arthroplasty patients. Journal of Orthopaedic Research. 2000. DOI: 10.1002/jor.1100180106
[14] POPULAR WEIGHT LOSS DIETS. Clinics in Sports Medicine. 1999. DOI: 10.1016/s0278-5919(05)70176-9
[15] Reply to: "Letter to the Editor Commenting on: 'Current Evidence Does Not Support the Use of Tibial Stem Extension in Total Knee Arthroplasty of Obese Patients: A Systematic Review'". The Journal of Arthroplasty. 2026. DOI: 10.1016/j.arth.2025.11.056
[16] Body mass index does not affect clinical outcomes following arthroscopically assisted posterior latissimus dorsi tendon transfer for irreparable posterosuperior rotator cuff tears: a minimum 5-year follow-up study. JSES Reviews, Reports, and Techniques. 2026. DOI: 10.1016/j.xrrt.2025.100634
[17] Cartilage contact characteristics of the knee during gait in individuals with obesity. Journal of Orthopaedic Research. 2022. DOI: 10.1002/jor.25288
[18] Overweight and Obese Patients Require Total Hip and Total Knee Arthroplasty at a Younger Age. Journal of Orthopaedic Research. 2019. DOI: 10.1002/jor.24460
[19] Exercise in the maintenance of weight loss: health benefits beyond lost weight on the scale. British Journal of Sports Medicine. 2021. DOI: 10.1136/bjsports-2021-104754
[20] Effect of exercise training on liver function in adults who are overweight or exhibit fatty liver disease: a systematic review and meta-analysis. British Journal of Sports Medicine. 2016. DOI: 10.1136/bjsports-2016-096197
[21] Obesity Class Does Not Associate With Incidence, Timing, or Invasiveness of Reoperations After Total Hip Arthroplasty. The Journal of Arthroplasty. 2026. DOI: 10.1016/j.arth.2025.07.026
[22] The Effect of Body Mass Index on Outcomes After Hip Arthroscopy for Femoroacetabular Impingement Syndrome: A Matched Analysis With 10-Year Follow-up. The American Journal of Sports Medicine. 2026. DOI: 10.1177/03635465251400355
[23] Age and obesity alter the relationship between femoral articular cartilage thickness and ambulatory loads in individuals without osteoarthritis. Journal of Orthopaedic Research. 2013. DOI: 10.1002/jor.22530
[24] Obesity and Total Knee Arthroplasty Revisited: Minimal Impact on Loosening and Mechanical Failure in the Modern Era. The Journal of Arthroplasty. 2026. DOI: 10.1016/j.arth.2026.04.031
[25] Report of the Arthritis Committee. The Journal of Hand Surgery. 1983. DOI: 10.1016/s0363-5023(83)80245-7
[26] Obesity is associated with higher 90-day and 2-year complication rates following surgical fixation of upper extremity fractures: A nationwide analysis. Injury. 2025. DOI: 10.1016/j.injury.2025.112891
[27] Body Mass Index is Not an Appropriate Proxy for the Condition of Peri-Incisional Adiposity in Primary Total Joint Arthroplasty Patients. The Journal of Arthroplasty. 2025. DOI: 10.1016/j.arth.2024.08.020
[28] Impact of high body mass index on functionally aligned image-based robotic total knee arthroplasty: Comparable functional outcomes but higher mechanical failures. Journal of ISAKOS. 2025. DOI: 10.1016/j.jisako.2025.100861
[29] Revision rates between obese and nonobese total shoulder arthroplasty patients: an Australian registry data study. Journal of Shoulder and Elbow Surgery. 2026. DOI: 10.1016/j.jse.2025.05.036
[30] Is Semaglutide a Safer Weight-Management Option Than Bariatric Surgery for Patients Undergoing Total Hip Arthroplasty (THA)?. The Journal of Arthroplasty. 2026. DOI: 10.1016/j.arth.2025.08.068
[31] Disparities in Preoperative Weight Loss and Obesity Treatment Before Total Joint Arthroplasty. The Journal of Arthroplasty. 2026. DOI: 10.1016/j.arth.2026.06.021
[32] Impact of pediatric obesity on surgical outcomes of lower extremity fractures: a nationwide analysis (2010–2019). BMC Musculoskeletal Disorders. 2026. DOI: 10.1186/s12891-025-09349-6
[33] Obesity is Associated with Higher Rates of Revision Following Unicompartmental Knee Arthroplasty. Orthopaedic Journal of Sports Medicine. 2026. DOI: 10.1177/2325967125s00336
[34] Obesity and load‐induced posttraumatic osteoarthritis in the absence of fracture or surgical trauma. Journal of Orthopaedic Research. 2020. DOI: 10.1002/jor.24799
[35] Soft Tissue-To-Bone Ratio Outperforms Body Mass Index in Predicting Periprosthetic Joint Infection in Total Knee Arthroplasty: A Retrospective Case-Control Study. The Journal of Arthroplasty. 2026. DOI: 10.1016/j.arth.2025.09.022
[36] Adolescent obesity incurs adult skeletal deficits in murine induced obesity model. Journal of Orthopaedic Research. 2022. DOI: 10.1002/jor.25378
[37] Neutralizing the odds: Biomechanical protection by adiposity offsets physiological burden to explain the trauma ’obesity-paradox’. Injury. 2026. DOI: 10.1016/j.injury.2025.112913
[38] Medial Meniscus Posterior Root Tear Repairs Show Osteoarthritis Progression Over Time With Higher Rates Seen With Higher Body Mass Index. Arthroscopy. 2026. DOI: 10.1002/arj.70028
[39] Body mass index moderates the association between gait kinetics, body composition, and femoral knee cartilage characteristics. Journal of Orthopaedic Research. 2020. DOI: 10.1002/jor.24655
[40] Effects of dietary fatty acid content on humeral cartilage and bone structure in a mouse model of diet‐induced obesity. Journal of Orthopaedic Research. 2019. DOI: 10.1002/jor.24219
[41] Obesity promotes lipid accumulation in mouse cartilage—A potential role of acetyl‐CoA carboxylase (ACC) mediated chondrocyte de novo lipogenesis. Journal of Orthopaedic Research. 2022. DOI: 10.1002/jor.25322
[42] Impact of body mass index on robotic-assisted total knee arthroplasty outcomes: A retrospective cohort analysis. Journal of ISAKOS. 2025. DOI: 10.1016/j.jisako.2025.100927
[43] Patellofemoral joint contact area increases with knee flexion and weight‐bearing. Journal of Orthopaedic Research. 2005. DOI: 10.1016/j.orthres.2004.08.003
[44] Primary Total Hip Arthroplasty in Patients Who Have Morbid Obesity: A Propensity-Weighted Analysis of Dual Mobility and Standard Fixed-Bearing Implants. The Journal of Arthroplasty. 2026. DOI: 10.1016/j.arth.2026.03.075
[45] Obese Patients Treated by Hip Arthroscopy for Femoroacetabular Impingement Syndrome — 10-Year Functional Outcomes and Conversion Rates to Arthroplasty Compared With Normal-Weight Patients. The American Journal of Sports Medicine. 2026. DOI: 10.1177/03635465251392585
[47] Impact Of Prior Bariatric Surgery Versus Immediate Total Knee Arthroplasty On Knee Function Among Patients Who Have Severe Obesity And Advanced Knee Osteoarthritis: The SWIFT Trial. The Journal of Arthroplasty. 2026. DOI: 10.1016/j.arth.2026.05.033
[48] Impact of high-intensity interval training vs. moderate-intensity continuous training combined with strength training on physical and metabolic outcomes in post-bariatric surgery patients with sarcopenic obesity. BMC Musculoskeletal Disorders. 2026. DOI: 10.1186/s12891-026-09722-z
[50] Editorial Commentary: Obesity and Osteoarthritis Are Risk Factors for Conversion to Arthroplasty, With or Without Previous Knee Arthroscopic Surgery. Arthroscopy. 2025. DOI: 10.1016/j.arthro.2025.04.036
[51] Do the Ten-Year Functional Outcomes and Revision Rates of Total Hip Arthroplasty in Obese and Morbidly Obese Patients Justify Restricting Their Access to Surgery?. The Journal of Arthroplasty. 2026. DOI: 10.1016/j.arth.2025.07.044