Increasing age is associated with worse sports function but not daily living function following arthroscopic anterior talofibular ligament repair

Abstract

Background

Arthroscopic anterior talofibular ligament repair (AATFLR) has been shown to restore ankle function effectively and to provide favourable clinical outcomes in chronic lateral ankle instability (CLAI). The present study was designed to identify variables associated with suboptimal postoperative sports-related functional recovery in patients with CLAI.

Methods

Patients who underwent AATFLR between December 2021 and February 2024 were included. Baseline characteristics including age, sex, body mass index, serum uric acid, concomitant avulsion/free bone fragments and osteochondral lesion of the talus were collected. Postoperative outcomes were assessed using the Foot and Ankle Ability Measure–Activities of Daily Living (FAAM-ADL), the FAAM-Sport score, the Karlsson score, the numeric rating scale pain score, and the Tegner score. Multivariable linear regression and ordinal logistic regression analyses were performed to identify variables associated with postoperative functional recovery. Regression coefficients are reported as β.

Results

A total of 197 patients were included, with a mean follow-up of 30.0 months. All functional outcomes improved significantly postoperatively (p < 0.001). Multivariate regression analyses demonstrated that increasing age was associated with lower postoperative FAAM-Sport score (β = − 0.51, 95% CI [− 0.78; -0.23], p < 0.001). However, no association was observed between age and the FAAM-ADL score (β = − 0.07, 95% CI [− 0.26; 0.12], p = 0.471). Increasing age significantly reduced odds of achieving higher postoperative Tegner activity levels (OR = 0.947, 95% CI [0.92–0.98], p = 0.002). Female sex was associated with lower postoperative Karlsson score (β = − 6.56, 95% CI [− 10.92; − 2.21], p = 0.003), which did not achieve the minimal clinically important difference. The overall complication rate was 31.0%, consisting predominantly of minor complications.

Conclusions

AATFLR significantly improved ankle function and reduced pain in patients with CLAI. Increasing age may be associated with poorer postoperative sports-related functional recovery after AATFLR. However, it may not affect activities of daily living. Sex may not be associated with postoperative functional recovery. Older patients with high athletic demands should be provided with more comprehensive preoperative risk counselling.

Level of evidence Level III, retrospective cohort study.

Supplementary Information

The online version contains supplementary material available at https://doi.org/10.1186/s13018-026-07079-6.

Introduction

Ankle sprain represents a common musculoskeletal injury in orthopaedics and sports medicine [1–4]. The anterior talofibular ligament (ATFL) is involved in the vast majority of ankle sprains [5–7]. In a substantial proportion of patients, inadequate ligament healing and incomplete restoration of joint stability may lead to chronic lateral ankle instability (CLAI) [6, 8, 9]. Patients with CLAI commonly present with persistent ankle pain, swelling, and subjective instability. Daily function, sports participation, and quality of life may therefore be markedly impaired.

Current clinical consensus recommends surgical intervention to restore ankle stability for CLAI patients who remain symptomatic after 6 months of standardised conservative treatment [10]. The open Broström-Gould procedure represents the traditional gold-standard technique and yields satisfactory clinical outcomes [11–13]. Over the past decade, arthroscopic anterior talofibular ligament repair (AATFLR) has been increasingly used for CLAI. This technique has several advantages. These include reduced postoperative pain, shorter rehabilitation time, simultaneous treatment of concomitant intra-articular pathology, improved cosmetic outcomes, and minimally invasive access [14–19].

Most clinical studies have shown that AATFLR effectively improves joint function and provides favourable clinical outcomes in patients with CLAI. Yet, marked interindividual variability in postoperative motor function recovery is observed in clinical practice. Clinical outcomes may also be affected by multiple factors [20–22]. Existing evidence suggests that outcomes following the AATFLR may be influenced by baseline patient characteristics and injury-related clinical factors [21, 23–25]. Clarification of the associations between these variables and postoperative functional recovery may help to identify prognostic determinants. It may also inform preoperative patient selection and individualised treatment planning. In addition, targeted therapeutic interventions may facilitate refinement of postoperative rehabilitation protocols. These measures may further improve the therapeutic efficacy of AATFLR and the prognosis of patients with CLAI. The aim of the present study was to determine which baseline characteristics were associated with suboptimal postoperative sports-related functional recovery in patients with CLAI. This retrospective cohort study was reported in accordance with the STROCSS 2025 guidelines for surgical observational studies.

Materials and methods

Study design

Patients with CLAI who underwent AATFLR at our institution between December 2021 and February 2024 were retrospectively enrolled. The study was based on retrospectively collected clinical data. Retrospective ethical approval was obtained from the institutional ethics committee (Approval No.: 2026-ER-037). Written informed consent was obtained from all included patients. The study was retrospectively registered on Research Registry (Registration number: researchregistry11964, available at: https://www.researchregistry.com/).

Eligibility and patient inclusion

The inclusion criteria were as follows: (1) diagnosis of CLAI and treatment with AATFLR; (2) fulfilment of the minimum diagnostic criteria for chronic ankle instability established by the International Ankle Consortium [26]; (3) a positive anterior drawer test confirming ATFL laxity and a negative inversion stress test; (4) ATFL injury confirmed by musculoskeletal ultrasound or magnetic resonance imaging (MRI).

The exclusion criteria were as follows: (1) significant lower-limb deformity or neuromuscular disease [27]; (2) generalised joint laxity identified on physical examination (Beighton score ≥ 4) [28]; (3) concomitant hip or knee disorders; and (4) new lower extremity injuries excluding ankle sprains during follow-up.

A total of 227 patients with CLAI underwent AATFLR between December 2021 and February 2024. Nine patients were excluded because of other lower-limb lesions or generalised joint laxity. A further 21 patients were lost to follow-up. Each patient was contacted at least three times by telephone and outpatient follow-up reminders. After repeated contact attempts, these patients either did not respond or explicitly declined further follow-up. Finally, 197 patients completed the full follow-up and were included in the study. An attrition analysis was performed to compare baseline characteristics between patients lost to follow-up and those who completed follow-up. No significant between-group differences were observed (Table S1). A detailed patient flow diagram is shown in Fig. 1.

Fig. 1.

Flowchart of patient enrolment. CLAI, Chronic lateral ankle instability; ATFL, anterior talofibular ligament

Data collection

Demographic and baseline clinical data were collected through medical record review. Baseline variables included age, sex, body mass index (BMI), and serum uric acid level. Injury-related variables included the injured side, associated avulsion or free bone fragments, and osteochondral lesions of the talus (OLT). In patients with concomitant OLT, all lesions measured less than 50 mm² on preoperative magnetic resonance imaging (MRI) and intraoperative arthroscopic assessment. According to the Hepple classification [29], 16 lesions were graded as stage I and 10 as stage IIa. Twenty-four lesions were located medially and two were located laterally. Arthroscopic debridement was performed in 16 patients. Microfracture was performed in 10 patients. These procedures were performed intraoperatively in accordance with clinical practice guidelines [30, 31]. The Foot and Ankle Ability Measure (FAAM, 0–100) comprising the Activities of Daily Living (FAAM‑ADL) and Sports (FAAM‑Sport) subscales, was used to assess functional outcomes, with the FAAM-Sport serving as the primary outcome measure. Additional secondary outcome measures included the Karlsson score (0–100), the Numeric Rating Scale for pain during exercise (NRS, 0–10), and the Tegner activity level score (0–10). Postoperative complications were categorised according to the Clavien-Dindo classification [32]. Preoperative functional scores were collected on the day of admission. Postoperative scores were obtained via telephone or outpatient interviews at the final follow-up.

Surgical technique

All procedures were performed by three well-trained foot and ankle surgeons with extensive clinical experience. Each surgeon had a similarly high arthroscopic caseload. Operations were performed under combined spinal-epidural anaesthesia and tourniquet control. The surgical technique was performed as described by Guo et al. [14]. Ankle arthroscopy used modified anteromedial (lateral to tibialis anterior) and anterolateral (lateral to peroneus tertius) portals. Synovial debridement preceded ATFL injury/laxity confirmation via probe. A 2.9-mm suture anchor was placed at the ATFL fibular footprint through the anterolateral portal. A lateral accessory portal was created 0.5–1 cm anterior to the lateral malleolus. A 22-gauge needle loaded with 3 − 0 PDS suture was passed through the ATFL remnant via this portal. A shuttle technique was then used. The anchor sutures were transferred from the anterolateral portal to the lateral accessory portal. One suture tail was configured as a lasso. The other tail was tensioned using the sliding mechanism of the anchor. Three square knots were tied to secure the repair. The second pair of suture tails was tightened using a simple suture technique to provide additional ligament reinforcement. If residual ligament laxity was confirmed by the hook test after repair, extensor retinaculum reinforcement was performed.

Concomitant intra-articular injuries identified during arthroscopy were documented and treated accordingly. These included OLT and associated avulsion or free bone fragments. Debridement or microfracture was performed for OLT. Avulsion or free bone fragments were removed intraoperatively.

Rehabilitation

An accelerated postoperative rehabilitation protocol (APRP) was implemented for all patients [33]. Briefly, the affected ankle was immobilised in a U-shaped plaster splint for 2 days. A semi-rigid ankle brace was then used for 3 weeks. This was followed by a soft ankle brace for an additional 4 weeks. Full weight-bearing was encouraged from the first postoperative day. Return to general exercise was permitted at 1 month after surgery. High-intensity sports activity was permitted at 3 months after surgery. Muscle strength, proprioception, and balance training were initiated as early as possible. The rehabilitation protocol was mainly home-based and was supervised by a physician. Routine outpatient follow-up and rehabilitation guidance were provided at 2 weeks, 1 month, 2 months, and 3 months after surgery. Telephone follow-up was used as an alternative for patients who did not attend outpatient visits.

Variable definition and screening

Continuous variables included age, follow-up duration, Karlsson score, FAAM-ADL score, FAAM-Sport score and NRS pain score. The Tegner score was defined as an ordinal categorical variable: low activity level (1–3), moderate activity level (4–6), and high activity level (7–10). Dichotomous variables included sex, affected side, overweight status (BMI ≥ 24 kg/m²), hyperuricemia (defined as serum uric acid > 420 µmol/L for men and > 360 µmol/L for women), presence of avulsed/free bone fragments, presence of OLT, and extensor retinaculum reinforcement. The cut-off values for BMI and hyperuricemia in the study were defined according to Chinese clinical diagnostic criteria [34, 35].

Statistical analysis

Statistical analyses were performed using SPSS version 26.0. Normally distributed continuous variables were presented as mean ± standard deviation (SD). Non-normally distributed variables were presented as median and range. All tests were two-sided. Statistical significance was set at p < 0.05. The paired t-test was used for longitudinal comparisons of normally distributed continuous variables between preoperative and postoperative data. The Wilcoxon signed-rank test was used for non-normally distributed or ordinal variables. Cohen’s d was reported to indicate the effect size of preoperative and postoperative comparisons.

Post-hoc power analysis was performed after data collection. With a two-tailed α of 0.05 and a target power of 0.90, the observed effect sizes of the FAAM-Sport score were used to calculate the statistical power of the present study. The results demonstrated that the current sample size (n = 197) achieved sufficient statistical power to detect clinically meaningful differences (Table S2). The minimal clinically important difference (MCID) values for the FAAM-Sport and FAAM-ADL subscales were 9 and 8 points, respectively. These values were derived from previous studies [36, 37]. The MCID of the Karlsson score was estimated using the 0.5*SD method [38]. The SD of the preoperative Karlsson scores in this study was 20.3. This yielded an approximate MCID of 10 points.

All continuous and dichotomous candidate variables were included as independent variables. Linear regression analyses were performed to identify correlates of continuous postoperative outcome measures. These outcomes included the FAAM-Sport score, FAAM-ADL score, Karlsson score, and NRS pain score. Univariate linear regression was first used to calculate regression coefficients (β) and 95% confidence intervals (95% CI) for each variable. All variables were then entered into multivariable linear regression models. Each multivariable model was adjusted for baseline demographic and clinical characteristics. These included age, sex, BMI, and hyperuricaemia. The models were also adjusted for concomitant injuries, including avulsion or free bone fragments and OLT, and for surgical factors, including extensor retinaculum reinforcement. The corresponding preoperative functional score was also included. These scores comprised the preoperative FAAM-Sport score, preoperative FAAM-ADL score, or preoperative Karlsson score. This adjustment was performed to account for baseline ankle functional status. Multicollinearity was assessed using the variance inflation factor (VIF). VIF values < 5 were considered acceptable.

Postoperative categorical Tegner activity scores were divided into low (1–3), moderate (4–6), and high (7–10) strata, with ordinal logistic regression used as the primary analytical method. Two supplementary binary logistic regression models with distinct Tegner score cutoffs were constructed; consistent effect estimates across these models provided indirect support for the proportional odds assumption. After univariable screening, multivariable ordinal logistic regression was fitted if the proportional odds assumption was satisfied. Identical covariates were adjusted in all regression models. Binary logistic regression stratified by different activity thresholds was also used as an alternative analysis. This was performed to examine whether the effect of age varied across activity levels. Odds ratios (ORs) and corresponding 95% CIs were reported for all models. Statistical significance was set at α = 0.05.

Results

Baseline characteristics

A total of 197 patients were enrolled in the present study, including 126 males and 71 females, with a mean age of 28.8 ± 9.1 years and a mean BMI of 23.3 ± 4.0. The affected ankle was left-sided in 101 patients and right-sided in 96, with a mean follow‑up duration of 30.0 ± 5.0 months (range, 24 to 43 months). Among them, 44 patients were associated with avulsion/free bone fragments, 26 with OLT, and 68 with hyperuricemia. Baseline characteristics are presented in detail in Table 1.

Table 1.

Demographic information (N = 197)

Characteristics	Results
Age, years	28.8 ± 9.1
Sex, n (%)
Male	126 (64.0)
Female	71 (36.0)
Side of operation, n (%)
Left	101 (51.3)
Right	96 (48.7)
BMI, kg/m²	23.3 ± 4.0
Hyperuricemia, n (%)	68 (34.5)
Associated injuries, n (%)
Associated avulsion/free bone fragments	44 (22.3)
Osteochondral lesion of the talus	26 (13.2)
Extensor retinaculum reinforcement, n (%)	108 (54.8)
Operation duration, minutes	54.5 ± 30.2
Latest follow-up, months	30.0 ± 5.0

BMI, body mass index

Clinical outcomes

All functional scores improved significantly after surgery. The FAAM-Sport score increased from 47.8 ± 32.9 preoperatively to 84.8 ± 18.2 postoperatively. The FAAM-ADL score increased from 71.8 ± 24.4 to 93.1 ± 10.1. The Karlsson score increased from 54.4 ± 20.3 to 86.1 ± 13.6. The NRS pain score decreased from 4.1 ± 2.4 to 0.7 ± 1.3. All preoperative-to-postoperative differences in pain and continuous functional scores were statistically significant (p < 0.001). Substantial to large effect sizes were observed (Cohen’s d = 0.88–1.32). These findings indicated marked postoperative improvement compared with baseline. Detailed data are shown in Table 2; Fig. 2.

Table 2.

Pain and functional outcomes (N = 197)

Functional Scores		Preoperative	Postoperative	Improvement	Cohen’s d c		p
NRS	4.1 ± 2.4		0.7 ± 1.3	3.3 ± 2.5	1.32	< 0.001a
Karlsson	54.4 ± 20.3		86.1 ± 13.6	32.5 ± 24.8	1.31	< 0.001a
FAAM-ADL	71.8 ± 24.4		93.1 ± 10.1	21.6 ± 24.6	0.88	< 0.001a
FAAM-Sport	47.8 ± 32.9		84.8 ± 18.2	37.1 ± 34.7	1.07	< 0.001a
Tegner	3 (2–6)		4 (3–6)	1 (0–2)	–	< 0.001b

NRS, numerical rating scale; FAAM, foot and ankle ability measure; ADL, abilities of daily living

^a Paired samples t test

^b Wilcoxon test

^c Cohen’s d represents the effect size for paired pre- vs. postoperative comparisons, calculated as the mean improvement divided by its standard deviation. Cohen’s d was not calculated for the Tegner score due to its ordinal nature

Fig. 2.

Comparison of preoperative and postoperative functional outcomes in CLAI patients after AATFLR. a Mean preoperative and postoperative Karlsson, FAAM-ADL, and FAAM-Sport scores. b Preoperative and postoperative NRS pain and Tegner activity scores. ***p < 0.001. AATFLR, arthroscopic anterior talofibular ligament repair; CLAI, chronic lateral ankle instability; FAAM-ADL, Foot and Ankle Ability Measure–Activities of Daily Living; FAAM-Sport, Foot and Ankle Ability Measure–Sport; NRS, Numeric Rating Scale

Prognostic analysis

Multivariable linear regression showed that increasing age was associated with a worse postoperative FAAM-Sport score. Each 1-year increase in age was associated with a 0.51-point decrease in the postoperative FAAM-Sport score (β = − 0.51, 95% CI − 0.78 to -0.23; p < 0.001). A higher preoperative FAAM-Sport score was associated with better postoperative sports function (β = 0.09, 95% CI 0.02 to 0.16; p = 0.019). Female sex was associated with a 4.67-point lower FAAM-Sport score. However, this association was not statistically significant (β = − 4.67, 95% CI − 10.31 to 0.93; p = 0.102) (Fig. 3). No other variables were significantly associated with postoperative FAAM-Sport score (Table 3). No variables included in this study were significantly associated with postoperative FAAM-ADL score (p > 0.05) (Table S3).

Fig. 3.

Identification of independent predictors associated with postoperative FAAM-Sport score in CLAI patients after AATFLR. a Forest plot displaying the regression coefficients (β) and 95% CIs for potential prognostic factors influencing postoperative FAAM-Sport score. Negative β values indicate poorer postoperative functional outcomes. b Scatter plot illustrating the correlation between age and postoperative FAAM-Sport score, with a fitted regression line showing a gradual decline in function score with increasing age. c Violin plot comparing the distribution of postoperative FAAM-Sport score between male and female patients. Value: ***p < 0.001; *p < 0.05. CLAI, Chronic lateral ankle instability; AATFLR, arthroscopic anterior talofibular ligament repair; BMI, body mass index; 95% CI, 95% confidence interval

Table 3.

Multivariate linear analysis of FAAM-Sport functional outcomes (N = 197)

Variable	VIF	β	95% CI	p a
Sex (male vs. female)	1.241	− 4.67	[− 10.31; 0.93]	0.102
Age (per 1-year increase)	1.095	− 0.51	[− 0.78; -0.23]	<0.001*
BMI	1.156	1.86	[− 3.45; 7.18]	0.490
Hyperuricemia	1.201	− 0.80	[− 6.38; 4.79]	0.778
Associated avulsion/free bone fragments	1.074	2.37	[− 3.22; 7.97]	0.404
Osteochondral lesion of the talus	1.040	− 1.23	[− 7.21; 4.75]	0.686
Extensor retinaculum reinforcement	1.075	− 3.55	[− 8.60; 1.50]	0.167
Preoperative FAAM-Sport score	1.021	0.09	[0.02; 0.16]	0.019*

VIF, variance inflation factor; BMI, body mass index; β = regression coefficient; 95% CI, 95% confidence interval; FAAM-Sport, Foot and Ankle Ability Measure sport

R² = 0.142, Adjusted R² = 0.105

VIF < 5 indicates no serious multicollinearity

^a Multivariate Linear regression analysis

* p < 0.05

Further, ordinal logistic regression showed that increasing age was significantly associated with lower odds of higher postoperative Tegner activity levels (OR = 0.947, 95% CI [0.92–0.98], p = 0.002), with a 5.3% reduction in odds per year. No significant associations were identified for other variables. The association between age and Tegner activity level remained statistically significant in binary logistic regression models, with the p value of 0.008 for the low versus combined moderate-to-high activity comparison, and 0.019 for the high versus combined low-to-moderate activity comparison. Further details are shown in Table 4.

Table 4.

Ordinal and binary logistic regression analyses of factors associated with postoperative Tegner activity level (N = 197)

Variable	Ordinal logistic regression				Model A(Low vs. Moderate+High)			Model B (Low+Moderate vs. High)
	OR	95% CI	p		OR	95% CI	p	OR		95% CI	p
Sex (male vs. female)	0.61	[0.34; 1.09]	0.096		0.58	[0.31; 1.08]	0.087	0.53		[0.19; 1.46]	0.219
Age (per 1-year increase)	0.95	[0.92; 0.98]	0.002*		0.95	[0.92; 0.99]	0.008*	0.94		[0.88; 0.99]	0.019*
BMI	1.18	[0.65; 2.12]	0.592		1.11	[0.58; 2.13]	0.746	1.13		[0.47; 2.70]	0.791
Hyperuricemia	1.35	[0.73; 2.51]	0.344		1.43	[0.72; 2.85]	0.308	1.34		[0.53; 3.41]	0.534
Associated avulsion/free bone fragments	1.21	[0.65; 2.25]	0.546		1.04	[0.53; 2.03]	0.921	2.21		[0.76; 6.44]	0.146
Osteochondral lesion of the talus	0.59	[0.31; 1.15]	0.124		0.60	[0.28; 1.26]	0.176	0.63		[0.25; 1.62]	0.340
Extensor retinaculum reinforcement	1.15	[0.65; 2.01]	0.635		1.40	[0.75; 2.60]	0.289	0.66		[0.28; 1.55]	0.338

OR, Odds Ratio; BMI, body mass index; 95% CI, 95% confidence interval

Model A: binary logistic regression comparing low versus moderate+high activity levels. Model B: binary logistic regression comparing low+moderate versus high activity levels

^a Multivariate ordinal logistic regression analysis, Wald test, the vertical dashed line at Odds ratio = 1 indicates no effect

* p < 0.05

Multivariable linear regression showed that female sex was associated with a worse postoperative Karlsson score. Female patients had a 6.56-point lower score than male patients (β = − 6.56, 95% CI − 10.92 to − 2.21; p = 0.003). No significant correlations were observed for age, BMI, hyperuricaemia, associated avulsion or free bone fragments, OLT, or extensor retinaculum reinforcement (Table 5; Fig. 4).

Table 5.

Multivariate linear analysis of Karlsson functional outcomes (N = 197)

Variable	VIF	β	95% CI	p a
Sex (male vs. female)	1.249	− 6.56	[− 10.92; -2.21]	0.003*
Age (per 1-year increase)	1.094	− 0.16	[− 0.38; 0.05]	0.139
BMI	1.154	− 0.13	[− 4.23; 3.97]	0.951
Hyperuricemia	1.205	0.43	[− 3.88; 4.75]	0.843
Associated avulsion/free bone fragments	1.074	0.08	[− 4.24; 4.40]	0.969
Osteochondral lesion of the talus	1.026	0.65	[− 3.94; 5.23]	0.781
Extensor retinaculum reinforcement	1.078	− 2.51	[− 6.42; 1.39]	0.206
Preoperative Karlsson score	1.022	0.01	[− 0.08; 0.10]	0.851

VIF, variance inflation factor; BMI, body mass index; β = regression coefficient; 95%CI, 95% confidence interval

R² = 0.085, Adjusted R² = 0.046

VIF < 5 indicates no serious multicollinearity

^a Multivariate Linear regression analysis

* p < 0.05

Fig. 4.

Identification of independent predictors associated with postoperative Karlsson score in CLAI patients after AATFLR. a Forest plot displaying the regression coefficients (β) and 95% CIs for potential prognostic factors influencing postoperative Karlsson score. Negative β values indicate poorer postoperative functional outcomes. b Scatter plot illustrating the correlation between age and postoperative Karlsson score, with a fitted regression line showing a gradual decline in function score with increasing age. c Violin plot comparing the distribution of postoperative Karlsson score between male and female patients. Value: **p < 0.01. CLAI, Chronic lateral ankle instability; AATFLR, arthroscopic anterior talofibular ligament repair; BMI, body mass index; 95% CI, 95% confidence interval

To eliminate potential confounding effects of concomitant injuries on the study outcomes, sensitivity analyses excluding patients with concomitant OLT and avulsion/free bone fragments were conducted, and no meaningful alterations were observed in the primary findings (Table S4–S6).

Complications

The overall postoperative complication rate was 31.0% (61/197). All recorded complications were classified as Clavien-Dindo grade I. No postoperative wound infection was observed. No symptoms related to nerve injury were reported at the final follow-up. The most frequent complications were mild limitation of ankle range of motion and occasional post-exercise ankle discomfort. Mild limitation of ankle range of motion was defined as limitation of ankle dorsiflexion or plantarflexion of no more than 10°. This complication occurred in 10.7% of patients (21/197). Occasional post-exercise ankle discomfort was reported in 8.6% of patients (17/197). These symptoms occurred after exercise rather than during daily activities. Persistent ankle swelling was reported in 7 patients (3.5%). Subjective ankle instability was reported in 9 patients (4.6%). Mechanical instability was identified in 7 patients (3.5%) (Table 6). No secondary surgical procedures were performed in any case. Binary logistic regression demonstrated that none of the variables showed significant correlations with either the overall incidence of postoperative complications (Table S7).

Table 6.

Complications

Complication Type	Total(N = 197)
Mild limited range of ankle motion, n (%)		21 (10.7%)
Post-exercise occasional ankle discomfort, n (%)		17 (8.6%)
Persistent ankle swelling, n (%)		7 (3.5%)
Subjective ankle instability, n (%)		9 (4.6%)
Mechanical ankle instability, n (%)		7 (3.5%)
Total complication cases, n (%)		61 (31.0%)

Discussion

The most important finding of the present study was that increasing age was associated with poorer sports-related function, but not with daily living function, after arthroscopic anterior talofibular ligament repair. In this large retrospective cohort, AATFLR significantly improved postoperative functional scores. These included the FAAM and Karlsson scores. Pain and activity levels also improved. Favourable clinical outcomes were achieved. Further multivariate analyses demonstrated that increasing age was significantly associated with poorer FAAM-Sport score but not FAAM-ADL score. Age was also associated with a lower likelihood of achieving a high postoperative Tegner activity level. Higher preoperative FAAM-Sport scores were associated with better postoperative sports function. However, the effect size was small and was unlikely to be clinically meaningful. Female sex was associated with a lower postoperative Karlsson score in multivariable analyses. However, the between-group difference did not reach the minimal clinically important difference. These findings suggest that age may be mainly associated with sports-related functional recovery after AATFLR. In contrast, age may not be associated with recovery in activities of daily living. The findings clarify the influence of baseline patient characteristics on surgical outcomes. They also provide evidence for individualised clinical assessment and optimised rehabilitation strategies.

With the continuous advancement of minimally invasive techniques, AATFLR has gradually become a widely used procedure for CLAI [39]. Most current studies have focused on optimisation of surgical approaches and improvement of suture anchor and knotting techniques. Generally satisfactory clinical outcomes have been reported [8, 15, 20, 22, 40, 41]. Nonetheless, with the wider use and expanded indications of AATFLR, baseline patient characteristics have also been recognised as potential determinants of postoperative functional recovery, in addition to technical factors [21, 24, 42]. Among various factors influencing postoperative recovery, the negative impact of age has been supported by multiple studies [20–22, 42]. Brilianto et al. analysed 75 patients and reported a significant negative correlation between age and both the postoperative Japanese Society for Surgery of the Foot (JSSF) score and the Karlsson score. Patients aged 40 years or older also had significantly poorer pain-related and general health scores than younger patients [42]. In a retrospective study involving 52 CLAI patients, Li et al. observed that older age was correlated with lower postoperative Karlsson and Tegner score [22].

The Karlsson score is a widely used composite scale for evaluating outcomes after AATFLR [43]. Pain, daily function, and subjective ankle stability are assessed with this scale. Yet, its validity evidence has been reported to be relatively limited [44]. In addition, only an overall functional score is provided. Therefore, differences between recovery in daily activities and recovery in sports function cannot be distinguished. In comparison, the FAAM score has been validated as a reliable tool for assessing outcomes in CLAI patients [45–47]. Notably, its ADL and Sport subscales allow clear differentiation between low-intensity daily activities and high-demand sports function. The FAAM-Sport subscale was designed specifically to assess sports-related functions. These include running, jumping, and cutting manoeuvres. Therefore, it may be more sensitive to postoperative sports recovery. Most previous studies have focused only on the negative impact of increasing age on the Karlsson score after AATFLR [21, 22]. However, no significant association between age and the postoperative Karlsson score was observed in the present study. Analyses using the FAAM scale showed that increasing age may mainly affect postoperative sports function rather than daily living function. This finding may have clinical implications. When outcomes after AATFLR are evaluated, use of the FAAM scale with stratified assessment may help to identify age-related differences in functional recovery more precisely. It may also provide more individualised evidence for postoperative rehabilitation planning and optimisation of recovery towards high-intensity sports activity.

This study yielded a notable finding complementary to prior evidence: increasing age was not significantly associated with the postoperative FAAM-ADL score. However, it was associated with a lower FAAM-Sport score. Each 1-year increase in age was associated with an average 0.51-point reduction in the FAAM-Sport score. Therefore, a 20-year age difference between patients would correspond to a difference of more than 10.2 points in the postoperative FAAM-Sport score. This exceeds the minimal clinically important difference [36]. Additionally, each 1-year increase in age was associated with an approximately 5% reduction in the likelihood of achieving a high postoperative Tegner activity level. Though a higher preoperative FAAM-Sport score was also associated with better postoperative sports function (β = 0.09, 95% CI 0.02 to 0.16; p = 0.019), each 1-point increase in the preoperative FAAM-Sport score was associated with only a 0.09-point postoperative improvement. This association was therefore unlikely to be clinically meaningful. These findings suggest that the potential adverse effect of increasing age on postoperative outcomes may be more evident in high-demand sports function. By contrast, relatively satisfactory recovery may still be achieved in low-intensity daily activities. This difference may be partly explained by several mechanisms. First, increasing age may be accompanied by gradual reductions in neuromuscular control, ankle dorsiflexion range of motion, and dynamic muscular stability, which might be inadequate to fulfil the precise coordination and explosive strength requirements of high-intensity athletic activities [48–50]. Second, studies have suggested that the healing capacity of the ATFL following CLAI may be relatively poorer with increasing age, which could potentially compromise the biomechanical stability after ligament repair [21, 51]. In parallel, age-related degenerative alterations within the ankle joint might further limit functional performance under high-load conditions [23]. High-intensity sports require greater muscular control, range of motion, and dynamic stability than daily activities. Therefore, age-related functional decline may be more pronounced in sports-related function. Its effect on basic daily living may be relatively mild. Age should therefore not be regarded as an absolute contraindication to surgery. However, patients should be informed before surgery that sports recovery may be limited. Intensified strength and proprioception training during rehabilitation may be considered to optimise postoperative activity levels.

Several previous studies have suggested a potential association between female sex and unfavourable clinical outcomes [20, 21]. In the present study, female sex was associated with a lower postoperative Karlsson score. Female patients had a mean score reduction of 6.56 points compared with male patients (p = 0.003). However, this between-group difference was lower than the minimal clinically important difference for the Karlsson score. Therefore, although statistical significance was reached, no clear clinically meaningful difference was observed between sexes. Further, no significant between-sex differences were detected in the FAAM-ADL or FAAM-Sport scores. Taken together, these findings suggest that sex may not have a clinically meaningful effect on overall postoperative functional recovery in the present cohort. In general, the relatively poorer functional recovery observed in female patients in previous studies may be explained by several factors. These include weaker peri-ankle muscle strength, reduced dynamic stability, potentially slower ligament healing, and sex-specific differences in gait biomechanics [48, 52, 53]. In the present study, sex appeared to have no significant correlation with postoperative outcomes, which may be attributed to the adopted accelerated postoperative rehabilitation protocol (APRP) [33]. Early full weightbearing and prompt initiation of range-of-motion and muscle strength training may have partially compensated for the inherent physiological disadvantages in females, such as muscle strength, stability, and ankle mobility [54]. The present rehabilitation protocol may also have improved subjective functional perception in female patients. As a result, the sex-related gap in functional recovery may have been narrowed. Future clinical practice may therefore benefit from more individualised rehabilitation strategies tailored to baseline characteristics, including sex [55]. In particular, intensified early training focusing on muscle strength, balance, and dynamic stability could be considered for female patients, with the aim of further optimising sports function recovery.

Whether the associated avulsion/free bone fragment in ATFL injury leads to differences in postoperative outcomes remains controversial [24, 56]. Xiong et al. retrospectively reviewed 39 patients with avulsion bone fragments who were treated by open repair. Combined avulsion fractures were associated with poorer postoperative Foot and Ankle Outcome Score (FAOS) [24]. By contrast, Feng et al. reported that arthroscopic repair for avulsion bone fragments achieved significantly better functional scores than open repair, implying that arthroscopic management may provide superior functional recovery in such patients [56]. In the present study, associated avulsion or free bone fragments showed no clear association with prognosis. This may be attributable to the all-inside arthroscopic repair technique and the APRP. These factors may have reduced the effect of avulsion or free bone fragments as potential limiting factors for functional recovery.

CLAI patients with OLT often present with more severe pain and relatively compromised sports function [57, 58]. Hua et al. reported that CLAI patients with OLT exhibited significantly lower postoperative AOFAS score than those without cartilage injury [17]. Cao et al. and Hua et al. also noted that OLT was associated with restricted ankle motion, increased joint loading, and uneven force distribution. These factors may hinder postoperative sports recovery [57]. In the present study, OLT did not appear to have a significant effect on prognosis. This may be explained by the relatively mild severity of OLT in this cohort. Among patients with concomitant OLT, all lesions measured less than 50 mm² and were classified as Hepple stage I–IIa. Weigelt et al. demonstrated that incidentally detected OLT without clinical symptoms had no adverse impact on long-term ankle functional outcomes [59]. Su et al. demonstrated that patients with small OLT lesions showed no significant differences in long-term pain or sports recovery compared with simple CLAI patients [60]. Chen et al. reported that larger OLT lesions were closely associated with unfavourable prognosis [21]. These findings suggest that OLT severity may be an important prognostic determinant. Mild lesions may recover satisfactorily with conservative or minimally invasive treatment. In contrast, large or deep lesions may contribute to increased pain and functional decline. Therefore, clinical evaluation should focus on the area, depth, and location of OLT, rather than only its presence. Given the relatively small sample size of the OLT subgroup in this study, further large-sample and well-designed studies are needed to investigate the relationship between OLT and surgical outcomes after AATFLR more robustly.

Ankle gouty arthritis has previously been misdiagnosed as ATFL injury [61]. However, no studies have investigated whether hyperuricaemia affects clinical outcomes after ATFL repair. Hyperuricaemia should be regarded only as a proxy indicator. Serum uric acid levels may remain normal during acute gout flares. In this study, no significant association was observed between hyperuricaemia and postoperative outcomes. Isolated hyperuricemia, in the absence of obvious gouty arthritis, synovial hyperplasia, or cartilage damage, may not be sufficient to adversely affect clinical outcomes following ATFL repair. The present analysis was purely exploratory. More rigorously designed studies are needed to clarify the effect of hyperuricaemia on surgical outcomes. In addition, BMI and extensor retinaculum reinforcement showed no significant associations with prognosis. These findings are consistent with previous studies [20, 62–64].

The overall postoperative complication rate in this cohort was 31.0%, which was higher than rates reported in previous studies [8, 21]. This discrepancy was likely due to comprehensive adverse event documentation in the present study. All complications were mild Clavien-Dindo grade I events. These included mild limitation of ankle dorsiflexion or plantarflexion, persistent ankle swelling, subjective and mechanical ankle instability, and intermittent exercise-related ankle discomfort. These symptoms did not interfere with daily activities. Notably, no cases of surgical site infection, permanent nerve injury, or secondary surgery were identified at the final follow-up. Binary logistic regression identified no variables associated with the occurrence of overall postoperative complications, suggesting that baseline clinical characteristics might not be associated with complication risk. Future studies should include larger sample sizes and complications of varying severity. This would improve statistical power and allow further exploration of variables associated with postoperative complications.

This study has several limitations. First, it was a single-centre retrospective study and was therefore subject to inherent selection bias. This included bias related to surgeons’ assessment of surgical indications and non-response bias. In addition, the analysis included only cases treated with arthroscopic ATFL suture anchor repair. Other viable surgical approaches, such as internal brace augmentation [11, 12] were not used in this cohort. Therefore, comparative analyses were not feasible. Second, not all potential clinical confounders could be included in the regression models because of the limited number of enrolled covariates. Small sample sizes in some subgroups may have led to insufficient statistical power. Variations in OLT characteristics, including lesion location, size, and depth, may have acted as unadjusted confounders and influenced the study outcomes. Surgical treatment for OLT may also have confounded postoperative outcomes. Third, although this study excluded patients with CFL rupture, we did not stratify by the presence of mild-to-moderate CFL injury. Systematic preoperative assessment of medial or multidirectional ankle instability was not performed. Psychological factors, including fear of reinjury, were also not assessed. Previous studies have shown that these factors can affect final clinical outcomes [65–67]. Additionally, although standardised postoperative rehabilitation guidance was provided, potential confounding effects from inconsistent rehabilitation implementation could not be fully excluded. Finally, longer follow-up is still needed to better assess long-term functional outcomes and prognosis.

Conclusion

The present study suggests that AATFLR significantly improves ankle function and relieves pain in patients with CLAI. Increasing age may be associated with poorer postoperative sports-related functional recovery after AATFLR. However, it may not be associated with recovery in activities of daily living. Sex may not be associated with postoperative functional recovery. In clinical practice, more comprehensive preoperative risk counselling should be provided to older patients with high athletic demands.

Supplementary Information

Below is the link to the electronic supplementary material.

Abbreviations

ADL

Activities of daily living

AATFLR

Arthroscopic anterior talofibular ligament repair

APRP

Accelerated postoperative rehabilitation protocol

ATFL

Anterior talofibular ligament

BMI

Body mass index

CI

Confidence interval

CLAI

Chronic lateral ankle instability

FAAM

Foot and ankle ability measure

FAOS

Foot and ankle outcome score

JSSF

Japanese society for surgery of the foot

MCID

Minimal clinically important difference

MRI

Magnetic resonance imaging

NRS

Numeric rating scale

OLT

Osteochondral lesion of the talus

OR

Odds ratio

SD

Standard deviation

Author contributions

HG and NS conceived the study. CZ and LL initiated the study design. All coauthors contributed to the refinement of the study protocol and to the implementation of the study. NS, CZ, LL, YC and XD drafted the manuscript. HG and BF revised the manuscript. All authors have reviewed and given their final approval of the submitted version.

Funding

This study was supported by Guangzhou Basic and Applied Basic Research Foundation (2025A04J3678), High-Tech Clinical Technology Projects of Guangzhou (2026P-GX013) and Key Clinical Techniques Projects of Guangzhou (2024P-ZD29).

Data availability

No datasets were generated or analysed during the current study.

Declarations

Ethics approval and consent to participate

This retrospective study was approved by the Ethics Committee of The Third Affiliated Hospital of Southern Medical University (approval number: 2026-ER-037). All patients included in the study provided informed consent.

Consent to participate

Written informed consent was obtained from all included patients before surgery.

Competing interests

The authors declare no competing interests.