Non operative ACL management

Non-Operative ACL Management: Strategies and Considerations

introduction

Anterior cruciate ligament (ACL) rupture is a musculoskeletal knee injury that is common in sports and patients frequently undergo ACL reconstruction.  There are often unrealistic expectations that prior knee function will be restored, prior activity levels attained, and further injury avoided [1].  Unfortunately, these goals are not often achieved after ACL reconstruction [2]. Previous systematic reviews highlighted that only 65% of patients return to their preinjury levels of sport and 36% develop knee osteoarthritis within 10 years of ACL reconstruction, a number that increases to 48% within the first 20 years after reconstruction [2]. 

Case Vignette

A 33 year old recreational runner presents with right knee pain and swelling since an injury three days ago. He was helping a friend move and his knee twisted while carrying a couch. He had knee swelling initially that worsened the following day. You examine him and his Lachman shows grade I laxity. He has not complained of any instability over the past few days. An MRI confirms your initial diagnosis of a full thickness ACL tear, but there was no meniscus tear or other ligament tear. Which of the following is true?

A) This should be a joint decision on solely operative management between provider and patient with balanced up to date information
B) He is not a candidate for nonoperative treatment due to this injury
C) A meniscus repair would be warranted along with an ACL reconstruction
D) If he does not plan on playing any sports involving cutting or jumping, he may be a candidate for nonoperative management

Both operative and nonoperative treatments of an ACL injury continue to evolve due to improved understanding of the structure and function of the native ACL and this has supported the development and adoption of anatomic ACL reconstruction techniques. In parallel, increased recognition of the resilience of the neuromuscular system in achieving dynamic, functional knee stability despite ACL deficiency has concurrently supported nonoperative treatment as a viable strategy in some patients [3,4].

ACL Anatomy

Image 1: ACL Anatomy.  ACL appears as a broad flat structure, shown here in the femoral notch, with its relations to the posterior cruciate ligament (PCL), medial femoral condyle (MFC), and lateral femoral condyle (LFC). MM (medial meniscus), AHLM (anterior horn lateral meniscus, LM (lateral meniscus)

The concept of differential patient presentation after ACL injury was first discussed by Noyes et al. in 1983 [5]. These authors introduced the “rule of thirds,” which hypothesized as many as 1/3 of patients with ACL deficiency could function well with some level of pivoting and cutting activity without having functional instability or “giving way.”  The other ⅔ would either function well only on the Activity of Daily Living Scale (ADLS) necessitating some level of activity modification or they would be unable to function at all with ACL deficiency due to instability. These patients would likely be indicated for surgical reconstruction. Essentially, these authors identified that a continuum of functional instability may exist in patients after ACL injury, ranging from grossly unstable to functionally stable with no giving way.

Identification of patients for potential non-operative management can be challenging. It should be a shared decision-making process.  This will likely necessitate a conversation with the patient, family, goals and expectations.  Indications for non-operative management include patients with partial tears, young children with wide-open physes, and patients with low-risk activity levels, isolated ACL injuries, and mild pathologic laxity [5].  There are also many other factors that matter to the deciding team including age, time of season (potential last season of competitive play), coach or parent influence and possibly other recommendations from people close to the individual that has suffered the injury.

screening

The theory of potential “copers” has advanced through a series of studies out of the University of Delaware over the last two decades [6]. This work proposed a comprehensive screening tool to identify patients likely to be able to successfully return to pivoting and cutting activity without an ACL reconstruction.  Unfortunately, no single assessment tool has been successful at identifying this subset of the ACL-deficient patient population who has potential to succeed with a non-operative course. 

This necessitated a more dynamic screening tool [7]. The screening tool proposed by Fitzgerald et al.  included four one-legged hop tests previously identified by Noyes et al. (single leg hop for distance, single leg triple hop, single leg triple crossover hop, and the 6-m timed hop test [8]), the incidence of knee giving way, a self-report functional survey (Knee outcome survey-Activity of Daily Living Scale—KOS-ADLS [9]), and a self-report global knee function rating.  Patients who presented without concomitant injuries who achieved a minimum score of 80% limb symmetry on all hop testing, >80% on the KOS-ADLS, >60 on the self-report of knee function, and ≤1 subjective report of knee giving way were considered “potential copers” [7].

With this particular protocol, Hurd et al. [7] published a 10-year outcome study on patients undergoing this screening to participate in non-operative care. These authors reported 54% of patients with an ACL injury were not eligible to participate in the screening due to concomitant injury, such as meniscal injury, chondral damage, other ligamentous injuries, or other factors. Of the remaining 46% of patients with ACL deficiency, less than half (20% of the population) were labeled as potential copers and even fewer successfully completed rehabilitation and were able to return to activity without surgical reconstruction.

current data

Other contrasting data has been reported as well.  A randomized controlled trial comparing operative and nonoperative treatment in 121 young, active, nonelite patients with isolated ACL tears demonstrated no superiority of either treatment with regard to patient-reported outcomes at 2- and 5-year follow-up [10].  However, almost 40% of the patients who were initially assigned to the nonoperative treatment group required delayed ACL reconstruction, and 32% of the patients (29 menisci in 19 patients) had subsequent surgery for meniscal injuries during the 2-year followup period. In contrast, 34 patients (56%) who underwent early ACL reconstruction also had meniscal treatment (24 partial resection, 10 fixation) simultaneously with the ACL reconstruction, but only 10% (6 meniscal injuries in 5 patients) in the operative group had meniscal injuries that required surgical treatment during followup [11].

Most studies investigating non operative ACL treatment or studies comparing nonoperative and operative treatment are limited to isolated ACL tears [10-12].   Based on clinical and biomechanical studies, an ACL reconstruction with concomitant meniscal repair may restore knee kinematics and result in improved patient-reported outcomes at short- and long-term follow-up. In contrast, simultaneously performing meniscectomy with ACL reconstruction is associated with poorer clinical outcome, inferior knee kinematics, and a high rate (48%-100%) of osteoarthritis in the long-term follow-up [13]. The presence of concomitant knee injuries should therefore always be considered in the decision-making process, given the worse outcomes for meniscal injuries with delayed ACL reconstruction and higher rate of osteoarthritis in the long term follow-up. In case of concomitant meniscal injury repair, anatomic ACL reconstruction with additional treatment of the meniscal injury is recommended.

In case of multiple ligament injuries involving the ACL and at least 1 other ligament, the literature has consistently demonstrated that operative management is superior to nonoperative management.  Based on a recent systematic review, early (within 3 weeks after injury) reconstruction in a multiple ligament–injured knee was superior to delayed reconstruction with regard to clinical outcome measurements (Lysholm score: 90 vs 82, respectively, of 100 points) and resulted in higher rate of excellent/good International Knee Documentation Committee (IKDC) scores (47% vs 31%, respectively) [14].  It is generally recommended to pursue ACL reconstruction if multiple ligament injuries exist.

Straight-plane activities are less demanding on the ligamentous stabilizers of the knee and therefore are amenable to nonoperative treatment. Examples of straight-plane activities include running, cycling, swimming and weight lifting.  With specific neuromuscular training (perturbation training) additional to standard rehabilitation, unphysiological muscular co-contractions during walking can be minimized and normalize the knee kinematics in the ACL-deficient knee [15]. In a matched-pair study, nonoperative treatment resulted in an earlier return (3-4 months vs 6-12 months, respectively) and a higher return to level II sports as compared with operative treatment [16].  Another study demonstrated a significantly higher number of nonoperatively treated patients returned to level II and level III sports compared with operative treatment [17].  Level I sports in these studies included handball, soccer, basketball and floorball.  Level II included volleyball, martial arts, gymnastics, hockey, tennis, skiing, snowboarding, dancing and level III included running, cycling, swimming and strength training. 

Therefore, the current evidence suggests a small percentage of patients can successfully return to pivoting and cutting sports, in the absence of an intact ACL. If a patient decides to pursue non-operative management in hopes of returning to pivoting and cutting sports, he/she should either participate in the successful completion of a rigorous screening tool.  If more straight-plane or lower level activity is anticipated and there are no meniscus or additional ligamentous injury, non-operative treatment is an option.

nonoperative protocols

Many protocols have been suggested in regards to acute and subacute treatment if non-operative management has been decided.  Each will have an initial phase that progresses activity and attempts to restore neuromuscular responses and proprioception. 

Many protocols have been suggested in regards to acute and subacute treatment if non-operative management has been decided.  Each will have an initial phase that progresses activity and attempts to restore neuromuscular responses and proprioception.

The initial or acute phase (phase I) is normally described as the first couple weeks and the goal is to restore knee impairments related to swelling and restore range of motion.  Patients with ACL injury typically present with a significant acute hemarthrosis, loss of motion, acute weakness in the involved extremity, and reflex inhibition of the quadriceps femoris musculature. Utilization of therapeutic exercise and appropriate modalities during the acute phase are essential to address these impairments [13].

Therapeutic interventions at this phase are often focused on restoration of full range of motion and key foundational strength deficits which must be addressed prior to implementing more dynamic interventions. The most common of these is quadriceps musculature weakness [15].  Typically, a combination of both open kinetic chain (OKC) activities to address residual isolated quadriceps weakness as well as closed kinetic chain (CKC) exercises to strengthen the quadriceps muscle while dynamically incorporating lower extremity movement is appropriate. The utilization of both OKC and CKC activities is seen as critical as OKC quadriceps strengthening may be more effective at addressing the isolated weakness [19].  Hamstring, core and hip weakness will also likely need to be addressed in a similar manner.

Nonoperative ACL protocol

Image 2.  Proposed nonoperative ACL protocol.  Adopted from [22].

Typically, a combination of both open kinetic chain (OKC) activities to address residual isolated quadriceps weakness as well as closed kinetic chain (CKC) exercises to strengthen the quadriceps muscle while dynamically incorporating lower extremity movement is appropriate. The utilization of both OKC and CKC activities is seen as critical as OKC quadriceps strengthening may be more effective at addressing the isolated weakness [19].  Hamstring, core and hip weakness will also likely need to be addressed in a similar manner.

Progression to the neuromuscular training phase of rehabilitation (phase 2) occurs when the patient has achieved full range of motion, resolution of effusion, and sufficient lower extremity strength to participate in more dynamic weight-bearing exercises [13]. During this phase, the patient continues to focus on maximizing lower extremity and core strength, but now can progress to participate in additional advanced balance, proprioception, cardiovascular conditioning, and neuromuscular interventions. 

As mentioned earlier, perturbation training is popular during ACL rehabilitation.  Perturbation training is designed to challenge the patient with ACL deficiency through a series of balance tasks enhanced with unanticipated perturbations to the unstable surface. It is classically described as a 10-session program and the patient begins with a stance on a rocker board and then progresses to a roller board [7].

Prior to progression to the return to sport phase (phase 3) of rehabilitation, the patient must demonstrate a successful completion of the neuromuscular training phase of rehabilitation with no episodes of giving way. In addition, the patient must present with sufficient quadriceps and hamstring strength, as demonstrated by isokinetic strength symmetry of >90% compared to the contralateral limb. Once these factors are achieved, the patient is ready to progress to the final phase of rehabilitation [13].

The final phase focuses on returning to sport-specific activities and will likely be variable depending on the level of activity one is returning to.  If the patient is attempting to return to pivoting and cutting sports, a functional brace is recommended to enhance stability.  Although the mechanism by which the brace enhances stability is not clear, some data suggests marginal reduction in anterior tibial translation and enhanced proprioception, both of which may contribute to a feeling of stability by the patient [20]. 

Agility tasks should begin in a straight line at sub-maximal speed and then be progressed with increased intensity of movement and more dynamic directions. Ultimately, full speed maneuvers in three planes of movement should be executed and mastered if returning to cutting or pivoting. These activities can then be progressed into sport-specific tasks based on the individual needs of the patient. For example, weight lifters may start with lower weights and movements and progress the weights and depth of their lifts.  A complimentary cardiovascular conditioning program is also recommended to reduce fatigue and future injury risk.

Summary

In summary, the evidence behind both operative and non operative management for ACL injuries are evolving.  There are many factors that come into play when making a decision and it should be a joint decision between the patient and provider with a realistic presentation of the current data.  This should include goals, expectations, concomitant injuries,  and many others.   Successful outcomes after both operative and nonoperative treatments necessitate progressive rehabilitation, which entails staged and phase-adjusted physical therapy with the aim to address impairments, achieve functional stability, and safely return to sport. There are still many that will attempt nonoperative treatment that may go on to have surgery if there is continued instability of the knee.

Case Conclusion

Answer D. There are many factors that come into play when making a decision and it should be a joint decision between the patient and provider with a realistic presentation of the current data. This is true for both operative AND nonoperative management of isolated ACL tears. Indications for non-operative management include patients with partial tears, young children with wide-open physes, and patients with low-risk activity levels, isolated ACL injuries, and mild pathologic laxity. In the vignette, running is considered a straight plane activity and is a low risk activity. If there is a meniscus injury or multiple ligaments involved, he would likely benefit most from ACL reconstruction. Nonoperative treatments necessitate progressive rehabilitation, which entails staged and phase-adjusted physical therapy with the aim to address impairments, achieve functional stability, and safely return to sport.

Beynnon BD, Johnson RJ, Abate JA, Fleming BC, Nichols CE (2005) Treatment of anterior cruciate ligament injuries, part I. Am J Sports Med 33(10):1579–1602
Paterno, Mark V. “Non-operative care of the patient with an ACL-deficient knee.” Current reviews in musculoskeletal medicine 10.3 (2017): 322-327.
– More Knee Pain from Sports Medicine Review: https://www.sportsmedreview.com/by-joint/knee/

– Read More @ Wiki Sports Medicine: https://wikism.org/ACL_Injury

References

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