Weak associations between body mass index and self-reported disability in people with unilateral anterior cruciate ligament reconstruction

Body Mass Index Between 15 and 30 Does Not Influence Patient-Reported Outcomes After Anterior Cruciate Ligament Surgery Using a 10-mm-Diameter Bone-Tendon-Bone Graft

Purpose

To investigate the relation between body mass index (BMI) and outcomes after anterior cruciate ligament reconstruction (ACLR) using 10-mm-diameter bone-patellar tendon-bone grafts.

Methods

In this retrospective study, the Surgical Outcome System was used to measure patient-reported outcomes before and after ACLR between 2015 and 2019. The inclusion criteria consisted on patients undergoing primary ACLR performed by the senior surgeon, with recorded age of 15 years or older and BMI of 15.0 to 30. The exclusion criteria included revisions, concomitant procedures, age younger than 15 years, and unknown BMI. Patients were divided into cohorts to evaluate the Marx Activity Rating Scale (MARS), Tegner, International Knee Documentation Committee (IKDC), and Lysholm scores at various time points from injury to 2 years postoperatively.

Results

A total of 137 patients (100 male and 37 female patients) with an average age of 33 years (95% confidence interval, 30.6-35.4 years) and average BMI of 23.58 (95% confidence interval, 23.1-24.0) were divided into those with a BMI of 15 to 23.4 (group A, n = 69) and those with a BMI of 23.5 to 30 (group B, n = 68). A significant difference in MARS scores was found between the BMI groups before treatment, with mean scores of 11.55 (group A) and 9.41 (group B) (P = .011), and Tegner scores showed significance at 2 years, with scores of 6.45 and 5.41 for groups A and B, respectively (P = .009). Daily function scores were all insignificant. Female patients exhibited no significant differences across any patient-reported outcome measures or time points. Contrarily, male patients showed a significant difference in pretreatment MARS scores (14.30 in group A vs 9.96 in group B, P = .011). Additionally, scores at 2 years depicted Tegner values of 7.40 in group A versus 5.30 in group B (P = .012) and IKDC values of 96.92 in group A versus 90.47 in group B (P = .048). All results for female and male patients aged 30 years or younger indicated no significance.

Conclusions

Regardless of patient age or sex, BMI is not significantly associated with patient-reported outcomes after ACLR using 10-mm-diameter bone-patellar tendon-bone grafts.

Level of Evidence

Level III, retrospective cohort study.

The influence of body mass index on physical activity engagement following anterior cruciate ligament reconstruction: A systematic literature review

Background

The objective of this study was to summarize available literature that explored the impact of body mass index (BMI) on physical activity participation among individuals who were subjected to the anterior cruciate ligament reconstruction (ACLR).

Methods

A total of three electronic databases, including Web of Science, Scopus, and PubMed, were comprehensively searched to identify relevant investigations. The following inclusion criteria were applied: (1) study design was observational; (2) participants underwent the ACLR; (3) BMI was estimated as a predictor variable; and (4) outcomes evaluated referred to physical activity. The risk of bias was assessed with the National Institutes of Health Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies.

Results

After a database search, 787 studies were found, and only 10 of them met each of the eligibility criteria and were included in the qualitative analysis. Regarding respondents' characteristics, 7171 individuals underwent ACLR, 4080 males and 3091 females, with a mean age of 25.5 years. Most importantly, the average BMI of the examined population was 24.9 kg/m2. In all studies, physical activity was evaluated subjectively using the Tegner activity scale and the Marx activity scale. The main findings unambiguously demonstrated that a negative relationship between BMI and physical activity engagement was observed. More specifically, there is convincing evidence that BMI over 25 kg/m2 harmfully affected subjectively assessed physical activity in individuals with a history of ACLR.

Conclusion

The results obtained in the presented research indicated that increased values of BMI were a factor that correlated with reduced physical activity levels in the ACLR population. Hence, taking into account the clinical and health implications of reduced physical activity participation, stimulation of a healthy lifestyle, such as a combination of adequately designed physical exercise and nutrition, seems necessary for the analyzed population.

Risk of Postoperative Stiffness Following Multiligamentous Knee Injury Surgery Is Not Affected by Obesity: A Multicenter Study

PURPOSE

The purpose of this study was to examine the relationship between obesity and postoperative stiffness following surgical management of multiligamentous knee injuries (MLKIs) using a large two-center cohort, by both 1) using binary cutoffs at various body mass indexes (BMIs) and 2) a linear regression model.

METHODS

190 consecutive patients who underwent surgical management of MLKIs between January 2001 and March 2020 were reviewed at two level 1 academic trauma centers. Patient demographics, surgical characteristics, and manipulation under anesthesia (MUA)/lysis of adhesions (LOA) were reviewed. Patients were stratified by obesity grades: grade 1 (BMI 30 to <35) grade 2 (BMI 35 to <40); grade 3 (BMI >40), and compared with a nonobese comparison group with BMI <30. Multivariate logistic regressions were performed, including the covariates of age, gender, BMI, acute versus chronic injury, external fixator, vascular injury, knee dislocation, and Schenck Classification. Fisher's exact test was used to compare rate of MUA between grades of obesity. Analyses were performed with R. Statistical significance was set at P < .05.

RESULTS

The mean BMI of the cohort was 29.2 kg/m². The mean overall follow-up was 27.2 ± 7.2 months (range: 14-142 months). There were 55 (29.1%) MUA procedures observed at a mean 3.77 ± 2.18 months (range: 1.8-9.7 months) after final MLKI surgery. No significant difference was found in BMI of patients who underwent a MUA compared to patients who did not (30.2 vs 28.8; P = .67). There was no significant difference in rate or time to MUA following MLKI surgery between groups, with logistic regression demonstrating no significance (P = .144). Use of external fixation at the index surgery (OR = 3.3 [95% CI: 2.2, 4.7; P < .0001]) and vascular injury (OR = 6.2 [95% CI: 1.8, 24.5; P = .005]) were found to be independent predictors for need for MUA.

CONCLUSION

No difference in risk for postoperative stiffness requiring MUA following surgery for MLKI was found based on BMI. At all BMI levels, there were no significant increase in need for postoperative MUA, suggesting at minimum a neutralizing effect of obesity on postoperative stiffness. In addition, patients with external fixator use and vascular injury at index surgery were found to be at significantly higher risk for postoperative stiffness requiring MUA following surgery for MLKI. Surgeons should be aware of the risk factors for arthrofibrosis when proceeding with surgical repair or reconstruction of two or more ligaments of the knee.

LEVEL OF EVIDENCE

III, multicenter retrospective cohort study.

Satisfaction with playing pre-injury sports 1 year after anterior cruciate ligament reconstruction using a hamstring autograft

BACKGROUND

Few studies have examined patient satisfaction with playing pre-injury sports after anterior cruciate ligament (ACL) reconstruction. The purpose of this study was to investigate patient satisfaction with playing pre-injury sport and identify factors associated with satisfaction.

METHODS

A total of 97 patients underwent unilateral ACL reconstruction using a hamstring autograft and returned to pre-injury sports 1 year after surgery. Patient satisfaction with playing pre-injury sport was assessed by a visual analog scale (VAS) and an ordinal four-grade scale. Problems related to the operated knee were also assessed. Knee muscle strength, single leg hop distance, knee laxity, subjective knee pain, and fear of movement/reinjury using Tampa Scale for Kinesiophobia-11 (TSK-11) were measured. Multivariate linear regression analysis was performed to determine the factors associated with patient satisfaction with playing pre-injury sport 1 year after surgery.

RESULTS

The average VAS score for patient satisfaction with playing pre-injury sports 1 year after surgery was 77.8 ± 20.2. Of the 97 patients, 87 patients (89.7%) answered "satisfied" or "mostly satisfied", whereas 51 patients (52.6%) had one or more problems. Multivariate linear regression analysis identified that the TSK-11 score was associated with patient satisfaction with playing a pre-injury sport 1 year after surgery.

CONCLUSION

Most of the patients who returned to pre-injury sports were satisfied with their outcomes. In contrast, approximately half of the patients had one or more problems after returning to play pre-injury sports. In particular, fear of movement/reinjury was significantly associated with patient satisfaction with playing pre-injury sport 1 year after surgery.

Higher Body Mass Index Adversely Affects Knee Function After Anterior Cruciate Ligament Reconstruction in Individuals Who Are Recreationally Active

OBJECTIVE

Our aim was to investigate the effect of body mass index (BMI) levels on quadriceps and hamstring strength and functional outcomes up to 6 months after anterior cruciate ligament reconstruction (ACLR) with hamstring tendon autograft (HTG).

DESIGN

Prospective, controlled study.

SETTING

University clinical laboratory.

PATIENTS

Ninety-one participants who had undergone unilateral ACLR with HTG were divided into 2 groups according to their BMI. The participants whose BMI were between 18.5 and 24.9 kg/m were included in group 1 (n = 50, age: 27.2 ± 6.7 years, BMI: 22.3 ± 1.6 kg/m) and those whose BMI > 24.9 kg/m were included in group 2 (n = 41, age: 30.2 ± 6.9 years, BMI: 28.0 ± 2.4 kg/m).

INTERVENTIONS

Quadriceps and hamstring strength, functional performance including hop, jump, and balance performance, and IKDC score.

MAIN OUTCOME MEASURES

Maximum voluntary isometric contraction of the quadriceps and hamstring muscles and the body mass were measured at 1, 3, and 6 months after surgery. Absolute peak torques and normalized peak torques to body weight for both limbs were recorded. Functional outcomes were evaluated at 6 months after surgery.

RESULTS

Normalized quadriceps strength improvement was lower in group 2 when compared with group 1 (F(2,178) = 6.23, P = 0.003). Group 2 also demonstrated lower scores in functional performance (P < 0.05). Normalized hamstring and absolute quadriceps and hamstring strength improvement was not affected by higher BMI level (P > 0.05).

CONCLUSIONS

Higher BMI levels adversely affect quadriceps strength capacity and performance in patients who have undergone ACLR with HTG. Clinicians should consider BMI levels of patients when assessing and targeting muscle recovery because it could negatively affect the success of the ACLR rehabilitation.

Younger age and hamstring tendon graft are associated with higher IKDC 2000 and KOOS scores during the first year after ACL reconstruction

PURPOSE

Although reference values in healthy subjects have been published for both the International Knee Documentation Committee 2000 subjective knee form (IKDC 2000) and the Knee injury and Osteoarthritis Outcome Score (KOOS), data obtained during the first year after anterior cruciate ligament reconstruction (ACL-R) are sparse. The aim was to establish patient reference values for both questionnaires at different time points and depending on nine individual patient characteristics during the first year after ACL-R.

METHODS

Prospectively recorded data from a hospital-based registry were retrospectively extracted from the database. IKDC 2000 and KOOS questionnaires were self-administered pre-operatively and 6 weeks, 3 months, and 6 and 12 months following primary ACL-R. Score values were compared according to nine individual patient criteria: gender, age, body mass index, level of activity, involvement in competition, previous contralateral knee injury and/or surgery, graft type, meniscal repair and/or cartilage lesions. The feature which had a significant and consistent impact on the outcomes was considered as main reference.

RESULTS

Two-hundred and nighty-eight patients met the inclusion criteria. Overall, the score values increased over time after ACL-R. At 12 months, they were significantly greater than at any other time point (p < 0.05). The main individual feature influencing the IKDC 2000 score was age. Patients below 30 years of age had up to 9 points higher IKDC 2000 score values at all time points (p < 0.05). The main individual characteristic influencing the KOOS score was graft type. Patients with hamstring tendon grafts (STGR) had up to 15 points higher KOOS score values than patients with bone-patellar tendon-bone (BPTB) grafts during the first months after ACL-R (p < 0.05). At 12 months, no differences in KOOS score values could be identified anymore.

CONCLUSIONS

Younger age (< 30 years) and STGR grafts were related to higher IKDC 2000 and KOOS score values within the first year after primary ACL-R. The patient reference values adjusted to age and graft provided in this study may help to identify patients with lower outcomes within the first year after ACL-R.

LEVEL OF EVIDENCE

Level III.

No effect of graft size or body mass index on risk of revision after ACL reconstruction using hamstrings autograft

PURPOSE

The current study investigated the distribution of hamstrings graft size and body mass index and any potential effect on the risk of revision surgery in a large prospective cohort of patients undergoing ACL reconstruction. More specifically, the aim of the study was to investigate whether larger graft size or smaller BMI would decrease the risk of revision after ACL reconstruction.

METHODS

A total of 4029 patients, prospectively registered in the Norwegian Knee Ligament Registry, were included in the study. Univariate Kaplan-Meier survival analyses (with log-rank tests) and the Cox proportional hazard (PH) regression model were applied to compare risk of revision between groups of patients. Mutual adjustment for gender, age, activity at the time of injury and fixation method of the graft was performed.

RESULTS

Graft sizes spanned from 5.5 to 11.0 mm and the median of 8.0 mm was reported in 42% of patients in the cohort. BMI was reported from 15 to 57 with a median of 25. 46% of patients were classified as overweight (WHO standards), while 23% of patients were obese. At a median of 2.5 years after surgery, 150 patients had undergone revision surgery. Although certain effects were seen in the unadjusted analyses, neither graft size (diameter) nor patient BMI did affect the risk of undergoing revision surgery in the adjusted analyses.

CONCLUSIONS

Graft size and BMI was not found to be independent risk factors for undergoing ACL revision surgery. In contrast to other studies, graft size of 8 mm or larger did not have a better outcome than smaller graft sizes. A relatively large group of overweight patients undergoing ACL surgery reflects the general increase in weight seen in Western societies. Although the current study differs from previous findings, it might indicate that graft diameter is less important than previously stated.

LEVEL OF EVIDENCE

Cohort study, II.

MRI analysis of peripheral soft tissue composition, not body mass index, correlates with outcomes following anterior cruciate ligament reconstruction

PURPOSE

To utilize MRI to assess the relationship between BMI, peripheral soft tissue composition about the knee, and surgical outcomes in patients undergoing primary ACL reconstruction. It was hypothesized that a fatty periarticular soft tissue composition may be better than BMI at predicting poor outcomes after ACL reconstruction.

METHODS

Fifty-eight patients who underwent primary acute ACL reconstruction were identified from the surgical database and their data were retrospectively reviewed. Patients were selected based on availability of 2-year IKDC outcome scores, BMI data, and preoperative MRI studies. To approximate peripheral soft tissue composition, novel measurements of axial MRI images were employed using PACS ROI measurement tool. Relationships were assessed between IKDC outcome scores and measures of body habitus including BMI, total knee area, knee fatty-connective tissue area, and fatty-connective tissue to bone size ratio.

RESULTS

The median BMI was 24.3 kg/m² (range 18.5-36.9). Median IKDC score was 81.0 (range 46-100). BMI was correlated with total knee area (R = 0.72) and periarticular fat (R = 0.53). Neither continuous BMI (n.s.) nor total knee area (n.s.) was predictor of IKDC outcomes scores. Periarticular fatty-connective tissue trended towards predicting negative outcomes (n.s.). Periarticular fatty-connective tissue to bone size ratio was a significant negative predictor of IKDC scores (p = 0.03). Patients with more fat than bone on axial MRI (ratio > 1, N = 34) reported a lower mean IKDC score compared to patients with a ratio < 1 (N = 24) (77.2 vs. 87.7, p = 0.0028). The top quartile (N = 14) of these ratios reported a mean IKDC score of 68.9, compared to 87.3 of the bottom quartile (p = 0.0001).

CONCLUSIONS

Periarticular soft tissue composition, as approximated by the novel MRI analysis of this study, is a better predictor of outcomes following ACL reconstruction than is BMI. This information can be utilized in guiding surgeon and patient expectations following surgery, either via a direct application of these measurements or heightened awareness of the importance of peripheral body habitus.

LEVEL OF EVIDENCE

III.