Treatment of anterior cruciate ligament injuries in older adults: A clinical review

Abstract

The anterior cruciate ligament (ACL) is essential for knee joint stability. Although ACL injuries primarily affect young and middle-aged athletes, their incidence among older adults is increasing. Substantial or complete ACL rupture may cause persistent instability despite conservative treatment; in such cases, ACL reconstruction (ACLR) surgery is generally considered the standard surgical treatment. Because older adults often have osteoporosis, joint degeneration, and comorbidities, as well as lower functional demands than younger patients, some surgeons recommend conservative treatment. However, recent studies have found that patients who undergo ACLR and ACL repair have better postoperative functional recovery than those who receive conservative treatment, although there remains no clear consensus regarding the optimal treatment. This review examines the characteristics of ACL injuries in older adults and compares treatment methods, with the aim of improving the management of these patients. Current evidence indicates that older adults who undergo ACLR achieve comparable functional outcomes to younger patients, suggesting that treatment decisions should focus on functional needs and overall health rather than age or comorbidities alone. All-inside techniques may provide better outcomes in older adults, while supplementary reinforcement fixation may benefit patients with osteoporosis.

Key Words: Older adults; Anterior cruciate ligament injury; Knee osteoarthritis; Anterior cruciate ligament reconstruction; Anterior cruciate ligament repair

Core Tip: Advanced age, generally defined as ≥ 50 years, is no longer considered a contraindication to surgical treatment of anterior cruciate ligament (ACL) injuries. ACL reconstruction, particularly using all-inside techniques, can achieve outcomes in older adults comparable to those in younger patients. Less-invasive ACL repair may be appropriate for selected patients with proximal ACL tears. Treatment decisions should be based on activity level, functional demands, comorbidities, and the extent of knee degeneration rather than chronological age alone.

INTRODUCTION

The anterior cruciate ligament (ACL) is essential for anteroposterior and rotational knee stability[1]. ACL injuries commonly result from sports-related trauma or accidents, and ACL reconstruction (ACLR) is one of the most commonly performed orthopedic procedures worldwide[2,3]. Inadequately treated ACL injuries can cause pain, persistent instability, functional limitation, and progressive joint degeneration. As quality of life and participation in recreational sports have increased, a growing number of older adults remain physically active and are consequently at greater risk of sports-related injury. This trend has contributed to the increasing incidence of ACL injuries in older populations[3,4]. In older adults, ACL injuries may also result from low-energy mechanisms, such as twisting or falls, rather than the higher-energy sports-related mechanisms more typical of younger patients. Arthroscopic ACLR is the most common surgical treatment and can help to restore knee stability and function through a minimally invasive approach[5]. However, differences in surgical technique, graft selection, and fixation strategy may influence outcomes, and no consensus has been reached regarding optimal treatment in older adults. Historically, concerns about poor bone quality, lower activity demands, and graft failure led many surgeons to recommend non-surgical management for older adults. Subsequent studies, however, have reported suboptimal outcomes and impaired quality of life following non-surgical treatment[6-8]. As older adults increasingly seek to maintain active lifestyles, interest in surgical treatment has grown, although further evidence is needed to clarify ACLR outcomes in this population[9]. This review synthesizes current evidence on ACL injuries in older adults and provides clinically relevant guidance for their management. We define “older adults” as individuals aged ≥ 50 years, consistent with the majority of recent ACL studies in this population.

This review examined existing publications on the characteristics and management of ACL injuries in older adults. We used a structured approach to identify relevant studies. PubMed, EMBASE, the Cochrane Library, and Web of Science were searched from inception through June 2026 using keywords, subject headings, and related terms, including “anterior cruciate ligament”, “ACL injury”, “elderly” (as well as “older”), “ACL reconstruction”, “conservative care”, “non-surgical management”, “clinical outcomes”, and “rehabilitation”, all of which were combined using the Boolean operators “AND” and “OR”. Studies were eligible if they met the following criteria: (1) Inclusion of older adults with ACL injuries (studies that defined the population as middle-aged and older were also included when their content and findings met the objectives of this review, and these studies were clearly identified); (2) Comparative studies (randomized controlled trials, cohort studies, or case-control studies), case series, or systematic reviews/meta-analyses with at least ten patients; (3) Reporting of more than one clinical outcome (e.g., functional scores, satisfaction, complication rates, or level of functional recovery); and (4) Publication in English. Case reports were excluded. We assessed the quality of included studies using the Oxford Centre for Evidence-Based Medicine levels of evidence and, where applicable, the Methodological Index for Non-Randomized Studies. The available evidence was then synthesized systematically, paying particular attention to clinically relevant outcomes and the practical application of different treatments for ACL injuries in older adults.

CHARACTERISTICS AND EVALUATION

Although older adults do not constitute the largest group of patients with ACL injuries, the number of knee ligament injuries among older adults is steadily increasing. This trend may reflect demographic changes, improved living conditions, and increased participation by older adults in physical activity and sports. ACL injuries in older adults tend to result from low-energy events, such as twisting while walking, slipping, or falling on stairs, whereas high-energy sports injuries occur almost exclusively in younger patients. Consequently, clinical signs may be less apparent in older patients, some of whom cannot recall the mechanism of injury, potentially resulting in persistent symptoms and delayed medical consultation[10]. In addition, older adults often have degenerative changes in the knee, and the signs of an ACL tear may resemble those of osteoarthritis (OA), complicating the initial differentiation. Furthermore, the location and type of ACL tear vary significantly between age groups. Silverman et al[11] found that type I tears are more common in older adults, whereas type III tears are more common in younger patients. In general, most ACL injuries involve tears within the ligament substance, whereas proximal ACL tears appear to be more common in older adults. Vermeijden et al[12] found a strong association between older age and proximal tears. Evidence regarding tear location remains limited. One proposed explanation is that age-related reductions in ACL vascularity may lead to mucoid degeneration, potentially increasing the tendency toward proximal tears. Other investigators suggest that older adults participate less frequently in sports involving forceful twisting and vigorous movements and that differences in movement patterns may influence tear location. Clinically, the higher frequency of proximal tears in older patients is important because these tears may be suitable for ACL repair, potentially offering selected older adults an alternative to reconstruction. Bone bruise patterns may also provide insight into the injury mechanism; bruises on the medial side of the knee are often associated with tears within the ligament substance, suggesting that different injury mechanisms may influence tear location[13].

Figure 1 presents a magnetic resonance imaging (MRI) image of ACL tears at different locations in older adults. A key characteristic of older adults with ACL injuries is the higher prevalence of concomitant meniscal and cartilage damage compared with younger patients[14]. Meniscal injuries are particularly common in older patients with ACL injuries, and advanced age is an independent risk factor for meniscal and cartilage damage. A high body mass index (BMI) also substantially increases the risk of meniscal and cartilage injuries[15]. The interval from injury to surgery also influences the prevalence of concomitant injuries in older adults. Studies have shown that among patients aged 40 years or older, those who underwent surgery 12 months or more after injury had a 93.9% prevalence of medial meniscal tears, compared with 43.3% among those who underwent surgery within 12 months. Medial meniscal bucket-handle tears were also markedly more common in the delayed group[16,17]. Notably, a delay of 90 days or more has not been shown to increase the risk of meniscal or cartilage injury in patients older than 40 years; however, when the delay exceeds 1 year, the risk of medial meniscal injury increases substantially. These findings suggest that for older patients with ACL injuries, surgery should not be delayed indefinitely, particularly in the presence of knee instability[15].

Figure 1 Preoperative sagittal T2-weighted fat-suppressed magnetic resonance imaging images of three older adults (≥ 50 years) with anterior cruciate ligament tears at different locations. A: Tear near the femoral insertion of the anterior cruciate ligament (ACL); B: Midsubstance tear of the ACL; C: Tear near the tibial insertion of the ACL.

Physical examination of older adults requires particular attention. The potential effects of joint degeneration, stiffness, and muscle loss on examination findings should be considered. Older patients may also have difficulty relaxing because of pain or tension, which can affect the examination. Bilateral comparison is important because examination of the unaffected knee allows ligamentous laxity to be assessed more accurately. If arthritis severity differs substantially between the knees, further evaluation is required. MRI is a reliable modality for evaluating ACL injuries; it can directly demonstrate the ACL’s morphology and abnormal signal and can also detect meniscal tears, cartilage damage, and other ligament injuries[18].

Since older adults have a higher prevalence of concomitant meniscal and cartilage injuries, MRI is particularly important in this population. Previous studies have proposed MRI-based classification systems for ACL tear location, and recent evidence has demonstrated that tear location can be reliably quantified on MRI by evaluating distal and proximal remnant lengths, helping surgeons select treatment options preoperatively[18-20].

In older adults with ACL injuries, assessment of comorbidities requires particular attention and should be considered as important as assessment of the injury itself. Older adults often have comorbidities such as cardiovascular disease, diabetes, chronic lung disease, and osteoporosis. Clinical studies have shown that advanced age, high BMI, greater comorbidity burden, and smoking are associated with a higher likelihood of recommendation for conservative treatment.

TREATMENT DECISION-MAKING

In the past, many surgeons have used broad indications for conservative treatment of older adults with ACL injury. However, selection of non-surgical treatment in older adults with ACL injury should be approached with caution and should adhere strictly to established indications. According to existing guidelines and expert consensus, non-surgical treatment is suitable for nonathletic patients older than 40 years with low physical activity demands[3]. Non-surgical treatment may be considered for patients with the following characteristics: No symptoms of knee instability, no meniscal or cartilage injury requiring surgical treatment, a low level of physical activity (such as a low Tegner activity score), surgical contraindications, or unwillingness to undergo surgery. Advanced age, high BMI, greater comorbidity burden, and smoking are associated with selection of non-surgical treatment. However, this tendency may delay surgical intervention in some patients who require it[21]. Therefore, recommendations for non-surgical treatment should be based on adequate clinical evaluation rather than solely on age or the presence of comorbidities. Standardized non-surgical treatment does not consist simply of rest and brace protection but should include an individualized rehabilitation program. Its core components include structured physical therapy, brace protection, activity modification, and lifestyle changes[22]. Successful non-surgical treatment requires the patient’s active participation and long-term adherence, which may make treatment more challenging. In a cohort study of 448 patients with complete ACL injury, van der List et al[23] found that 60% of patients who initially received non-surgical treatment eventually required ACLR. The failure rate of non-surgical treatment varied significantly by age: 88.9% in patients younger than 25 years, 56.0% in patients aged 25-40 years, and 32.9% in patients older than 40 years.

Satisfaction after non-surgical treatment may represent a “false positive”, because satisfaction is assessed mainly through subjective surveys and does not necessarily indicate objective, stable recovery of knee function. Studies have shown that rotational stability was not restored in 83% of patients after non-surgical treatment[8]. Ehlinger et al[6] conducted a prospective study of 320 patients older than 50 years with ACL injuries. Although functional scores improved in the non-surgical treatment group, pivot-type exercises remained nearly impossible, and activity scores decreased significantly.

In addition to the widely used ACLR, ACL repair has garnered increasing attention. Arthroscopic primary repair of proximal ACL tears avoids tunnel drilling and graft harvesting, thereby preserving the native ligament and bone stock; these potential advantages have led some investigators to advocate for this approach, with early case series reporting favorable short-term outcomes in appropriately selected patients[24-26]. Notably, successful repair has also been reported in individual cases with chronic injuries or in athletes requiring rapid return to high-level competition, suggesting that the indications for this technique may continue to evolve[27,28]. Although earlier studies reported high failure rates with primary repair in young patients[12], several ACL repair techniques have been developed based on tear location. These techniques predominantly involve suture repair of femoral-sided ACL tears. Previous studies have demonstrated that femoral-sided tears can be approximated directly to the femoral wall and may have superior healing potential compared with midsubstance tears. Given that older adults more commonly present with femoral-sided tears, ACL repair may result in fewer complications and less surgical trauma than ACLR in this population. Van der List et al’s systematic review and meta-analysis[29] also confirmed that arthroscopic one-stage repair is a safe option in specific patients, with a failure rate of approximately 7%-11%.

Appropriate indications must be considered when selecting patients for ACL repair. A systematic review and meta-analysis by Rilk et al[30] demonstrated that revision rates after primary ACL repair were higher than those after reconstruction in skeletally mature patients younger than 21 years, whereas no significant difference was observed in adults older than 21 years. Furthermore, a recent meta-analysis comparing suture-augmented ACL repair with ACLR found that repair was associated with a significantly higher failure rate (9.8% vs 3.3%; odds ratio = 4.00)[31]. These findings suggest that ACL repair may be suitable for older patients with acute proximal tears, but the risk of failure is higher in patients with chronic injuries or midsubstance tears. ACL repair should therefore be performed only in patients who meet strict indications.

The indications for ACLR in older adults are generally consistent with those in younger populations, although individualized assessment of each older patient is required. Numerous studies have demonstrated that older adults can achieve outcomes comparable to those of younger patients following ACLR[32], a finding corroborated by a 10-year follow-up study[33]. Osteoporosis increases surgical complexity and the risk of fixation failure, prompting surgeons to approach ACLR with caution in affected patients. However, recent evidence indicates that osteoporosis does not significantly increase failure rates following ACLR and that all-inside tunnel preparation techniques offer several potential advantages over full tibial tunnel approaches. These advantages include better preservation of bone stock due to reduced tunnel widening[34], and the technique is supported by favorable clinical outcomes in comparative studies and systematic reviews[35,36]. The safety and efficacy of the all-inside technique have been further supported by expert commentary and technical reviews[37-39], with the graft-link technique providing a specific method for achieving these results[40]. Lubowitz et al[40] described an anatomic single-bundle all-inside ACL graft-linking technique utilizing second-generation FlipCutter guide pins (Arthrex, Inc., FL, United States), which can be reversed to function as retrograde drills and preserve additional bone stock. The technique also uses second-generation cortical suspensory fixation devices with adjustable graft-loop lengths, allowing graft tension to be increased after fixation. Theoretically, this technique is particularly advantageous for older adults with osteoporosis. Additionally, some investigators have proposed supplementary fixation to reduce the risk of fixation failure and cortical depression in osteoporotic patients[41,42].

For patients with confirmed osteoporosis (T-score ≤ -2.5), we recommend combining an all-inside reconstruction technique, bilateral cortical suspensory fixation, and additional fixation devices to enhance stability. This approach preserves bone stock and reduces tunnel enlargement and the risk of cortical fracture. In patients with very poor bone quality, bone nails or suture buttons may also be considered for supplementary reinforcement. Several studies have found that graft type does not significantly influence postoperative outcomes in older patients; however, this finding requires further validation through longterm followup and larger sample sizes[9,43]. Given concerns regarding graft rejection and healing, we recommend prioritizing autografts whenever feasible. Nevertheless, allografts may be considered according to individual patient needs and preferences.

Given the often insidious presentation of ACL injuries in older adults, some patients experience a prolonged interval between the initial injury and definitive diagnosis, complicating treatment decisions. Mueller et al[44] demonstrated that chronic proximal ACL injuries do not adversely affect delayed ACLR outcomes; thus, older adults remain candidates for surgical intervention even when diagnosis is delayed. Regarding graft selection, such concern may be unwarranted because clinical evidence indicates that graft type does not significantly influence clinical outcomes. Figure 2 presents the decision-making algorithm.

Figure 2 Clinical decision-making algorithm for anterior cruciate ligament injuries in older adult patients. ACL: Anterior cruciate ligament; MRI: Magnetic resonance imaging; BMI: Body mass index; HT: Hamstring tendon; LET: Lateral extra-articular tenodesis; ACLR: Anterior cruciate ligament reconstruction; OA: Osteoarthritis.

CLINICAL OUTCOMES IN OLDER ADULTS

D’Ambrosi et al[9] reported that in patients aged ≥ 50 years, mean postoperative IKDC scores ranged from 78.1 to 81.4, and Lysholm scores reached 91.2. In their cohort, 63.8% of patients returned to their pre-injury activity level, 83.9% rated their outcome as “very good” or “excellent”, 91.5% reported that the surgery met their expectations, and 88.2% achieved an acceptable symptomatic state. An age-stratified study demonstrated no statistically significant differences among three groups (20-29 years, 40-49 years, and 50-65 years) in terms of range of motion, clinical scores, or stability testing; however, graft failure rates varied across groups, with 10-year survival rates of 93.5%, 90.3%, and 82.4%, respectively[33]. Other investigators have similarly shown no significant differences between patients aged ≥ 60 years and those aged 40-59 years regarding revision surgery rates, re-rupture rates, range of motion, or IKDC improvement; furthermore, no significant differences were observed between patients older than 60 years and those aged 50-60 years[45]. Collectively, these findings indicate that age is not an independent predictor of prognosis.

The outcomes of ACL repair and reconstruction in older adults require further study. Available evidence suggests that short-term functional outcomes may be similar between repair and reconstruction, although the risk of re-rupture after repair is higher in younger patients[12,30]. Among older adults (≥ 50 years), the failure rate of primary suture-augmented repair is approximately 6%[31], lower than the 17% reported in younger patients and comparable to reconstruction outcomes in this age group. These age-stratified data support ACL repair as a feasible option for older adults with proximal tears.

Reported complication and revision rates varied widely (0%-40.4%), with the highest rates observed in studies with a greater prevalence of preoperative chondral lesions; overall, the graft re-rupture rate remained low at 0.3%[9]. An analysis of 46545 patients identified advanced age, male sex, elevated BMI, bone-patellar tendon-bone grafts, meniscectomy, prolonged injury-to-surgery interval, and concomitant meniscal or cartilage injuries as factors that increase the risk of postoperative knee OA[46]. A study with more than 20 years of follow-up study demonstrated that the vast majority of patients who developed knee OA following ACLR demonstrated only mild OA in the long term, with fewer than one-third progressing to moderate or severe disease[47]. Another study demonstrated that symptomatic ACL-deficient patients older than 60 years can benefit from ACLR, even in the presence of mild-to-moderate preoperative OA[48]. Table 1 summarizes the key outcomes of the three treatment approaches.

Table 1 Objective to compare the results of non-surgical treatment, anterior cruciate ligament repair and anterior cruciate ligament reconstruction in older adults.

Outcome metric	Non-operative treatment	ACL repair	ACL reconstruction
Patient selection	Low activity demand, no instability, surgical contraindications	Acute proximal femoral-side tears	Most surgical candidates, including chronic tears and midsubstance tears
Knee stability restoration	Poor (83% rotational instability persists)[8]	Good in selected patients	Excellent and predictable
Return to pre-injury activity	Limited (pivot activities almost infeasible)[6]	Moderate, depends on selection	Approximately 64%[9]
Failure/re-rupture rate	33%-60% eventually require surgery[23]	Approximately 6% in older adults (age-dependent)[12]	0.3%-7.1%[9]
10-year survival	N/A	Limited long-term data	82.4% (≥ 50 years)[31]
Conversion to TKA	Not well documented	Limited data	Limited data
Advantages	Avoids surgical risks	Preserves native ligament, less invasive, bone stock preservation	Most predictable outcomes, applicable to all tear types
Limitations	High failure rate, persistent instability	Strict selection required, limited evidence	More invasive, graft-related morbidity, OA risk

TKA: Total knee arthroplasty; OA: Osteoarthritis; ACL: Anterior cruciate ligament; N/A: Not applicable.

Advanced age itself is a recognized risk factor for OA; however, further long-term follow-up studies are needed to fully elucidate the risk of OA progression. Based on current evidence, ACLR does not appear to prevent OA, yet the majority of patients develop only mild degenerative changes that do not substantially compromise long-term quality of life.

Special attention should be paid to postoperative rehabilitation in older adults. Given their reduced physiological reserve, greater burden of complications, and increased risk of falls, older adults require rehabilitation programs tailored to their needs rather than those of younger patients. Current evidence indicates that early rehabilitation progression in older adults is slower than in younger patients. Neuromuscular and balance training is particularly important for reducing fall risk and compensating for age-related muscle atrophy. Decisions regarding return to daily activities should be based on functional tests (e.g., jump tests with a limb symmetry index ≥ 85%) rather than on time alone. Preoperative physical therapy (prehabilitation) has also been shown to improve postoperative outcomes. Current evidence on rehabilitation guidance and functional follow-up in older adults after ACLR remains insufficient to meet clinical needs. More detailed rehabilitation protocols are required, particularly for different treatment strategies[48,49].

FUTURE DIRECTIONS

Management of ACL injuries in older adults remains an important area for future orthopedic research. Despite recent advances, in-depth clinical evidence remains limited. Larger multicenter studies with longer follow-up are needed to compare the outcomes of ACLR and repair for tears at different locations in older adults. Evidence on postoperative rehabilitation programs tailored to specific age groups and surgical methods remains insufficient. Future research should focus on developing and validating programs suited to the physiological characteristics and functional goals of older adults. Graft suturing techniques in older adults warrant further investigation[50]. The long-term risks of surgery also remain insufficiently studied. Not all older adults with ACL injury need surgical treatment. The optimal indications for non-surgical management and tailored rehabilitation programs for older adults undergoing non-surgical management warrant further study.

OA remains a major concern in older adults following ACL injury because its high prevalence in this population, particularly among those with a history of ACL injury, substantially impairs quality of life. Although appropriate treatment may help slow OA progression, comprehensive long-term follow-up studies examining OA incidence and overall treatment costs are urgently needed to guide clinical decision-making.

CONCLUSION

ACL injuries are increasingly common in older adults in clinical practice, and patient outcomes warrant attention. Although non-surgical treatment is successful in some older adults, it is not generally recommended because nearly one-third of patients subsequently require surgical treatment, and knee stability often remains poor. Arthroscopic ACL repair is a viable option for older adults with proximal tears. Arthroscopic all-inside ACLR has yielded favorable outcomes in older adults, with postoperative outcomes comparable to those in younger patients. Treatment decisions for older adults with ACL injury should not be based on age alone but should be individualized according to patients’ functional needs, knee stability, and overall health status. Surgical treatment can therefore be considered a first-line option for older adults. Future studies should investigate rehabilitation programs tailored to older adults after ACLR.