Introduction
The all-epiphyseal anterior cruciate ligament (ACL) reconstruction techniques are efficacious alternatives to traditional ACL reconstruction (ACLR) techniques in skeletally immature patients. Current trends in pediatric orthopedics show the growing popularity of the all-epiphyseal ACLR. In a survey study of 71 members of Pediatric Research in Sports Medicine, 33% of pediatric orthopedic surgeons recommended an all-epiphyseal ACLR technique in a hypothetical 8-year-old patient with a complete ACL tear.
The all-epiphyseal reconstruction primarily consists of tibial and femoral tunnels or sockets isolated to the epiphyses. We typically employ an all-epiphyseal ACLR technique in patients with a significant degree of remaining growth, usually with a skeletal bone age of 13 years and younger in males and 12 years and younger in females. Several variations of the all-epiphyseal technique have been developed because it was initially described by Anderson et al. Together, the all-epiphyseal techniques share a common objective: to achieve the most anatomic graft placement within the notch and decrease the risk of iatrogenic physeal damage by securing the graft within the epiphysis without compromising the metaphysis. Fig. 14.1 shows two types of all-epiphyseal reconstruction: the transepiphyseal technique (Anderson technique) and the all-inside all-epiphyseal technique.
Although we believe pediatric epiphyseal ACLR techniques have shown a good safety profile in early studies, , , numerous preoperative, intraoperative, and postoperative considerations must be considered to minimize the incidence of complications. In this chapter, we will discuss the incidence of the following complications of all-epiphyseal ACLR: growth arrest, angular deformity, limb length discrepancy, graft failure/rerupture, contralateral ACL rupture, arthrofibrosis, and infection.
Additionally, we will describe preoperative, intraoperative, and postoperative considerations when utilizing the all-epiphyseal ACLR techniques in the pediatric population.
Complications
Growth Arrest
In a series of 12 patients (mean age 13.3 years) who underwent transepiphyseal ACLR using hamstring autograft, Anderson et al. reported no significant growth disturbances. More recently, Nawabi et al. performed a physeal-specific magnetic resonance imaging (MRI) technique to quantify the zone of physeal injury following all-epiphyseal reconstruction techniques. It was concluded that all-epiphyseal reconstruction results in minimal growth plate compromise does did not supersede the published thresholds for growth arrest.
Although the all-epiphyseal techniques were developed to provide femoral and tibial reconstruction tunnels or sockets that avoid crossing the physes, the risk of iatrogenic physeal injuries still exists. Measures to decrease this likelihood of growth disturbance include the use of soft tissue grafts in place of bone tendon grafts. Numerous authors have described success of the all-epiphyseal reconstruction with soft tissues grafts. , , Cordasco, Mayer, and Green described a case series of 23 patients treated with the all-inside all-epiphyseal reconstruction, in which a small physeal violation (<5% surface area of the physis) by either the femoral or tibial tunnel was seen in 12 patients. Although no clinically significant growth disturbances were noted, six patients had a limb-length discrepancy of more than 5 mm that did not require treatment. The largest retrospective series to date of all-epiphyseal ACLR outcomes by Cruz et al. noted growth arrest in a single patient out of the 103 that were followed for an average of 21 months postoperatively. As with many complications associated with all-epiphyseal ACLR, larger studies with long-term follow-up are necessary to establish the true incidence of growth disturbances.
Angular Deformity
Angular deformity is a rare complication of all-inside all-epiphyseal reconstruction relative to transphyseal reconstruction techniques. Koch et al. described a case series of 12 patients who underwent all-epiphyseal reconstruction in which one patient developed a significant limb-length discrepancy with 20 mm of overgrowth and varus malalignment after a second reconstruction. Although angular deformity could be the result of all-epiphyseal reconstruction, mechanical axes data was only available postoperatively, and physiological limb axes differences could not be excluded in this patient. We discuss a rare case of angular deformity secondary to all epiphyseal ACLR in the case presentation later.
Limb-Length Discrepancy
Limb overgrowth after all-epiphyseal ACLR has been observed in numerous independent case series of all-epiphyseal reconstruction. , , Theoretical explanations of this phenomena include a possible mechanical stimulation of the physeal growth plate zone via adjacent surgery in addition to an increase in epiphyseal blood flow. Out of 23 cases of all-inside all-epiphyseal ACLR, Cordasco, Mayer, and Green found overgrowth of more than 5 mm and less than 20 mm in six patients (26%). Similarly, Koch et al. described a series of 12 patients where six (50%) patients demonstrated overgrowth, two of which presented with a limb-length discrepancy greater than 20 mm. Preoperative and frequent postoperative radiographs are thus recommended to monitor growth disturbance to initiate timely clinical management or surgical management if necessary.
Rerupture
The risk of rerupture either because of reinjury or construct failure is not uncommon among the pediatric and adolescent populations after initial ACLR, and can occur via contact or noncontact mechanisms. , Anderson reported two instances of graft failure and one meniscal tear out of 13 patients, whereas Cruz et al. found a rerupture rate of 10.7% and a subsequent meniscal injury rate of 2.9% in 103 patients. Cordasco, Mayer, and Green noted a single case of rerupture and meniscal injury in a series of 23 patients.
Age has been identified as an independent risk factor for both reinjury of the reconstructed ACL and contralateral ACL injury with high rates of overall secondary ACL injury in younger cohorts. , , In a study of 561 patients with a mean follow-up of 4.8 years, Webster found that patients under the age of 20 years at the time of surgery were six times more likely to sustain a graft retear compared with the older cohort. Furthermore, Kaeding et al. reported that the odds of sustaining an ipsilateral ACL retear decreased by 0.09 for every year increase in age. ,
Returning to high-level competitive sports involving sprinting, cutting, and pivoting, such as soccer and football, can greatly increase the risk of rerupture. Young athletes in particular need to be cautious when returning to competitive levels of activity because of nonmodifiable risk factors including generalized joint laxity, knee recurvatum, increased lateral tibial slope, and decreased intercondylar notch width. Preinjury biomechanical/functional risk factors, in addition to compensatory changes during rehabilitation, are often missed by the quantitative measures of knee function. , , Although quantitative measures are essential for monitoring progress toward return to sport, these measures do not appropriately capture the quality of motion. Graziano et al. investigated the effectiveness of a criteria-based rehabilitation program that included a time-specific progression of strength goals with a focus on improving neuromuscular coordination. Patients were cleared for full activity only when both qualitative and quantitative motion milestones were met. Of the 42 patients included in the study, all but three returned to their primary sport within a year of ACLR. Of the six patients in the study who sustained reinjury, three engaged in sports for which they had not been cleared. Of note, all ACL reinjuries occurred in the setting of cutting sports.
Contralateral Rupture and Non-Anterior Cruciate Ligament Injuries
Contralateral ACL rupture postreconstruction is a well described occurrence following ACLR. In a retrospective review of 103 patients treated with all-epiphyseal ACLR, Cruz et al. noted two cases of contralateral ACL ruptures, indicating an incidence of 2%. Shelbourne et al. highlighted this concern, citing a contralateral ACL injury rate of 5.3% in a study of 1415 patients with 5-year follow-up. In a case series of 23 patients treated with all-epiphyseal reconstruction followed over 2 years, it was noted that many patients had strength and neuromuscular control deficits on the contralateral limb that were addressed with the goal of decreasing the likelihood of future injury. Although qualitative motion assessment and postoperative rehabilitation can help minimize the risk of contralateral ACL injury, nonmodifiable risk factors such as ligament laxity, intrinsic hormonal differences, and biomechanical tendencies may put the patient at risk for secondary ACL injury.
To assess pediatric patient outcomes after index ACLR surgery, Dodwell et al. conducted a statewide epidemiological study in New York to determine rates of ipsilateral ACL reinjury and subsequent reconstruction, contralateral ACLR, and other non-ACL knee surgery and to identify potential risk factors associated with these additional surgeries. Of the 23,912 patients included in the study, 1955 (8.2%) underwent subsequent ACLR, and 3341 (14%) had subsequent non-ACL knee surgery on the same side or on the contralateral side. Risk factors for additional ACL knee surgery included younger age at the time of primary ACLR, white race, and private insurance. The authors concluded that higher rate of reoperation in younger patients could in part be attributed to higher-risk activities in younger children and nonanatomic reconstruction techniques used in younger patients.
Arthrofibrosis
Arthrofibrosis is a well-documented complication of ACLR. Risk factors include early operative treatment and concomitant meniscal damage associated with ACL tears. , Koch et al. noted a single case of arthrofibrosis in a series of 12 patients who underwent all-epiphyseal reconstruction; Cruz et al. described the largest case series of 103 patients who underwent all-epiphyseal reconstruction and noted two cases of arthrofibrosis necessitating manipulation under anesthesia. The prevention of arthrofibrosis requires an early and aggressive rehabilitation after ACLR. Physical therapy must be personalized to each patient’s functional status postoperatively. A progressive rehabilitation program that emphasizes flexion, extension, early weight bearing, and range-of-motion exercises can be initiated a few weeks after surgery. Pace et al. conducted a review of 74 patients with arthrofibrosis after a knee procedure that did not resolve with physical therapy. It was noted that over half of these patients had undergone ACLR. Dynamic splinting constructs decreased the need for manipulation under anesthesia and lysis of adhesions in 58% of patients included in the study. Further studies investigating the potential role of dynamic splints in this population are necessary. It is our protocol to proceed with lysis of adhesions and manipulation under anesthesia if there is a significant knee contracture after 3 months of postoperative physical therapy.
Infection
Although rare, superficial infections have been documented in the setting of ACLR at a frequency of about 1% to 2%. , Intraoperative infection leading to a septic joint is also rare, but remains a possible complication. More commonly cited are postoperative skin infections, which occur secondary to stitch infection and are often painful and/or discolored. It is essential to maintain intraoperative sterility measures to avoid joint infection. Patients should also be educated about appropriate dressing changes and postoperative wound care. Postoperative septic arthritis should be treated with urgent arthroscopic debridement and intravenous antibiotics.
Case Presentation
This is an 11-year-old boy who sustained a right ACL tear while playing a contact sport and underwent all-epiphyseal ACLR with a hamstring autograft. Preoperative examination revealed a knee with ACL insufficiency, a 2B Lachman, and a 2+ pivot shift. Mild bilateral symmetrical valgus was noted on preoperative standing radiographs ( Fig. 14.2 ). Immediate postsurgical radiographs show epiphyseal placement of the ACL graft ( Fig. 14.3A ).
