All-epiphyseal Reconstruction Research Articles

Anatomic all-epiphyseal ACL reconstruction with "inside-out" femoral tunnel placement in immature patients yields high return to sport rates and functional outcome scores a minimum of 24months after reconstruction.

To understand if anatomic physeal-sparing ACL reconstruction in the immature host preserves range of motion, permits a return to sports, and avoids limb length discrepancy and accelerated intra-articular degeneration with a cross-sectional radiographic, physical examination and patient-reported outcomes analysis. A cross-sectional recall study included 38 patients aged 7-15 who underwent all-epiphyseal ACL reconstruction with hamstring allograft performed by a single surgeon at a large academic medical center. All-epiphyseal reconstructions were performed using a modified Anderson physeal-sparing technique, with the femoral tunnel placed using an "inside-out" technique. Assessments consisted of a physical exam, long leg cassette radiographs, KT-1000 measurements, subjective patient metrics, and magnetic resonance imaging. Thirty-eight (56.7%) of 66 eligible patients returned for in-person clinical and radiographic exams. Patients were 11.4 ± 1.8years at the time of surgery. Five patients were females (13.2%). Mean follow-up was 5.5 ± 2.4years. ACL re-injuries occurred in four patients (10.5%), all of whom underwent revision reconstructions. Thirty-three of the remaining 34 (97.1%) patients returned to sports following their reconstruction, and 24 (70.6%) returned to their baseline level of competition. Mean limb length discrepancy (LLD) was 0.2 ± 1.4cm. Nine patients had an LLD of > 1cm (26.5%), which occurred at an equivalent age as those with < 1cm LLD (10.8 ± 2.0 vs. 11.7 ± 1.7, n.s.). Pre-operative Marx scores (13.1 ± 3.5) were not significantly different from post-operative values (12.3 ± 5.1, n.s.). Patients who required ACL revisions had significantly lower Marx scores than those with intact primary grafts (8.3 ± 7.1 vs. 13.4 ± 4.5, p = 0.047). Cohort mean International Knee Documentation Committee (IKDC) score was 89.7 ± 12.7. Anatomic all-epiphyseal anatomic ACL reconstruction appears to be useful in patients with significant projected remaining growth, with good return-to-sport outcomes and minimal risk of clinically significant physeal complications. However, given the limited patient recall possible in the present study, further large sample size, high-quality works are necessary to validate our findings. Level IV.

Anterior Cruciate Ligament Injuries in Skeletally Immature Patients: A Meta-analysis Comparing Repair Versus Reconstruction Techniques.

Anterior cruciate ligament (ACL) surgery remains challenging in the skeletally immature patient. Despite the widespread use of physeal-sparing reconstruction techniques, there has been renewed interest in the ACL repair. The purpose of this study was to systematically review the literature to better understand outcomes following all-epiphyseal (AE) reconstruction to extraphyseal reconstruction, while also evaluating ACL repair outcomes in skeletally immature patients. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, all studies in the literature from January 1970 to August 2019 reporting on skeletally immature patients undergoing ACL surgery were identified. Inclusion criteria were pediatric patients with open physes indicative of skeletal immaturity sustaining complete ACL ruptures treated with AE reconstruction, extraphyseal reconstruction or ACL repair. Chronologic age, bone age, postoperative outcomes scores, return to sport rate, and the incidence of complications, namely reruptures, were analyzed. A total of 14 studies comprising 443 patients were identified. No significant difference in chronologic age or postoperative outcome scores at final follow-up were appreciated between patients undergoing AE versus extraphyseal reconstruction. Return to activity rate was significant greater following extraphyseal reconstruction when compared with AE reconstruction. The incidence of any limb-length discrepancies and limb discrepancies measuring ≥10 mm were significant higher following AE reconstruction, while rerupture rates were more common following AE reconstruction. Patients undergoing AE reconstruction possessed significantly lower return to activity rates, higher incidences of limb-length discrepancies and more commonly experienced ACL reruptures when compared with patients undergoing extraphyseal reconstruction. Further investigations analyzing results following ACL repair in skeletally immature patients are warranted to allow for the comparison of outcomes with current physeal-sparing reconstruction techniques. Level IV-systematic review-therapeutic study.

ACLR GRAFT STRAND NUMBER: LONG-TERM FOLLOW-UP ON 400 PATIENTS

Background:Studies on pediatric anterior cruciate ligament reconstructions (ACLRs) often focus on graft choice, as rates of these injuries have risen in recent years. Large multicenter studies have found younger age and smaller graft size to be risk factors for graft failure and contralateral tears, but despite large sample sizes these studies have not looked specifically at graft strand number. Therefore the purpose of this study was to use a large sample size to ask whether ACLR graft strand number affects long-term outcomes.Hypothesis/Purpose:Examine long-term effects of ACLR graft strand number using a large cohort.Methods:This was a retrospective comparison study of all patients presenting between 1/1/2008 and 12/31/16 for a first-time ACLR at a single pediatric hospital. After querying medical records for all ACLRs using CPT codes, graft strand number, graft diameter, and other variables were abstracted. Long-term outcomes on graft rupture, contralateral ACL tear, and subsequent meniscus injury were collected via phone calls and REDCap emails. Patient groups were compared for differences in graft strand number and diameter using bivariate analyses, and differences in long-term outcomes were analyzed using multivariate regression.Results:436 patients met the inclusion criteria also completed the long-term follow-up on outcomes. Long-term follow-up ranged from 18 months post surgery to 10 years post surgery. Patients with larger graft diameter were significantly less likely to suffer a complication (graft rupture, contralateral ACL tear, or subsequent meniscus injury) in multivariate regression (p=0.03), while strand number, sex, weight, and age showed no significant difference. Transphyseal reconstructions had larger graft diameters (8.8mm) than partial hybrid (8.6mm) and all-epiphyseal reconstructions (8.3mm) (p<0.001), but had no differences in graft strand number. Males had larger graft diameters (8.9mm) than females (8.6mm) (p=0.03), but also had no differences in graft strand number. Obese patients had larger graft diameters (9.1mm) than overweight (8.9mm) and normal weight patients (8.6mm) (p=0.002). Obese patients also had more graft strands (6.9) than overweight (6.2) or normal weight patients (6.1), but this difference was not significant (p=0.051).Conclusion:This data supports the existing literature that pediatric ACLR patients with larger graft diameters are less likely to suffer long-term complications. Using both a large patient cohort and long-term follow-up, this data also showed that graft strand number was not significantly correlated with outcomes. This suggests that strand number is not important when constructing ACLR grafts, as long as sufficient graft diameter can be achieved.

BIOMECHANICAL COMPARISON OF ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION TECHNIQUES USING A NOVEL ROBOTICALLY SIMULATED PIVOT SHIFT: A CADAVERIC STUDY

INTRODUCTION: The robotically simulated clinical pivot shift (PS), a dynamic loading profile based on measurement of loads applied by a surgeon, was developed as a more robust test for detecting kinematic changes for evaluating ACL reconstructions [2]. Two ACL reconstruction techniques were evaluated in this study: the all-epiphyseal (AE) and over-the-top (OTT). These techniques are used exclusively in the pediatric population in lieu of traditional techniques so as not to disrupt the epiphyseal in growing patients. Both techniques’ effectiveness in restoring intact knee kinematics has been examined previously in a cadaveric study, concluding that both techniques provide anterior and rotational stability, but no conclusions were made as to which technique provided more stability [1]. This study aimed to use the simulated clinical PS to assess anterior and rotational stability provided by the AE and OTT surgical techniques. METHODS: Six fresh-frozen, cadaveric legs were transected mid-femur and mid-tibia and mounted to the Universal Musculoskeletal Simulator capable of real-time force feedback using simVITROTM software. Four surgical conditions were tested: Intact knee, deficient ACL, AE reconstruction and OTT reconstruction. The AE and OTT reconstruction order was randomized. For each surgical condition, three tests were performed: Anterior drawer (134 N anterior, 20 N compression) at 0, 15, 30, 60, and 90° of flexion Rotary loads (5 Nm internal rotation torque, 10 Nm valgus torque, 20 N compression) at 5, 15, and 30° of flexion Simulated clinical PS test [2] For each specimen, the kinematics from the intact knee for each respective test was subtracted from the kinematics of the three remaining surgical conditions to acquire kinematic response relative to the intact knee. Relative anterior tibial translation (ATT) and internal tibial rotation (ITR) were reported at each tested flexion angle for the Anterior Drawer and Rotary Loads tests and for the flexion angle initiating the shift in the simulated clinical PS test. This angle was at the peak ATT and corresponded to the start of the shift. Paired t-tests were used to determine significance (p&lt;0.05). In one specimen the simulated clinical PS could not induce a shift, even in the deficient state, and thus was excluded from the analysis. RESULTS: Figure 1A displays the ATT and ITR for the simulated clinical PS at the flexion angle initiating the shift. Neither surgery restored intact knee kinematics. OTT exhibited 4.2 mm more ATT compared to AE (p=0.021) and 7.2° more ITR (p=0.015). OTT had no significant kinematic difference compared to the deficient ACL. Figure 1B displays the ATT for the Anterior Drawer test. The AE surgery significantly reduced ATT compared to deficient at flexion angles of 0, 15 and 30°. No significant difference between OTT and deficient was established. Figure 1C and 1D display the ATT and ITR (respectively) for the Rotary Loads test. Neither surgery restored intact knee kinematics nor significantly reduced ATT or ITR compared to the other surgery, agreeing with previous work with similar loading conditions[1]. DISCUSSION: The all-epiphyseal technique, though unable to restore native kinematics, showed significantly improved stability (4.2 mm ATT, 7.2° ITR) compared to the over-the-top technique when tested with a robotically simulated clinical pivot shift. Analysis of the Anterior Drawer and Rotary Loads tests did not detect significant differences in these surgical techniques, and are in agreement with a previous study which utilized similar loading conditions [1]. Limitations of our study include the small sample size, and the removal of one of the specimens. More work is needed on refining the loading profile to ensure it is able to induce a pivot shift in all specimens. While there is still room for improvement, it is currently still more effective than Rotary Loads, especially in its ability to detect rotational instabilities. The results from our study agree with previous studies [1, 2] in that the Rotary Loads test does not induce large rotational changes amongst ACL surgical states. It also does not provide additional information compared to the Anterior Drawer test for measuring anterior laxity. It is our recommendation that the Rotary Loads test be replaced by the simulated clinical PS when comparing biomechanical advantages of ACL reconstruction techniques in in vitro testing. SIGNIFICANCE: This study provides evidence that the novel robotically simulated clinical pivot shift is a more robust test for detecting kinematic changes when evaluating ACL reconstructions compared to the traditional Anterior Drawer and Rotary Loads tests. It also provides evidence that the All-Epiphyseal technique for reconstructing the ACL restores native kinematics better than the Over-the-Top technique. REFERENCES: [1] McCarthy et al., Am J Sports Med. 41,6: 1330-1339,2013 [2] Colbrunn et al., Pro ASME SBC, SCC2013-14288, 2013

RE-TEAR AND RE-OPERATION RATES FOR PEDIATRIC AND ADOLESCENT ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

BACKGROUND Anterior cruciate ligament (ACL) injuries have become increasingly common in pediatric and adolescent patients over the last several decades, as this population has become more involved in athletic competition. ACL injuries in skeletally immature patients had historically been treated conservatively with bracing and activity modification; however, poor outcomes including extensive chondral and meniscal damage, increased recurrent instability, and increased sports drop out rates have been observed. Recognition of these poor outcomes has led to a shift towards early operative treatment, resulting in a significant rise in the number of pediatric ACL reconstructions being performed. Yet, a higher failure rate has been noted in this younger population within larger adult cohort studies. The purpose of this study was to evaluate the re-tear and re-operation rates in pediatric and adolescent ACL reconstruction. METHODS The was a retrospective review of pediatric and adolescent patients treated at a single tertiary children’s hospital for ACL reconstruction from 2011 to 2017 by the same pediatric orthopedic surgeon. Review of the electronic medical record was performed to obtain patient demographics, preoperative clinical and radiographic findings, operative notes, and postoperative outcomes. Re-tear and re-operation rates were calculated. RESULTS A total of 308 patients were identified during the study period of which sixty-six percent were female. The mean age of patients was 15.8 years with a mean follow-up of 1.8 +/- 0.8 years. Two-hundred fifty-three hamstring autografts (mean age 15.7+/- 4.1 years) and 55 bone tendon bone autograft (mean age 16.9 +/- 1.45 years) were performed. Two hundred forty-three patents had adult-style reconstructions performed, 40 had transphyseal reconstructions, 24 had partial transphyseal reconstruction, and 1 patient had an all-epiphyseal reconstruction. Average hamstring graft size was 8.3 mm +/- 0.5 mm and all BTB graft were 9 mm. The overall graft re-tear rate was 8.2%. The overall re-operation rate was 13.2% (17 revisions, 5 medial meniscus repairs, 3 I+D’s, 2 cyclops debridements, 1 removal of hardware, and 1 manipulation under anesthesia). The highest re-tear (12.5%) and re-operation (22.5%) rates were found in patients who underwent a transphyseal reconstruction. No growth disturbances which required surgical intervention were noted. CONCLUSIONS / SIGNIFICANCE Pediatric and adolescent ACL reconstruction can be performed safely without a risk of growth disturbance. Patients had a high re-tear and re-operation rate; particularly in patients who underwent transphyseal reconstruction. Strategies must be developed to decrease the re-tear and re-operation rate in this population.

VARIATION IN PREFERRED TECHNIQUE FOR ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION IN THE SKELETALLY IMMATURE: WHERE DO WE STAND?

Purpose: Despite several well-described operative techniques, the optimal management of anterior cruciate ligament (ACL) injuries in pediatric patients remains unclear. The goal of this study was to identify preferred techniques in skeletally immature patients of various ages and analyze differences in operative strategy based on surgeon and practice demographics. Methods: An electronic survey was administered to members of the Pediatric Research in Sports Medicine society, a cohort of experienced surgeons who perform a high volume of pediatric ACL reconstructions. The survey presented a scenario of a patient who had a physical exam and imaging consistent with an acute, isolated ACL tear. The respondent was asked to select their preferred reconstruction technique for females and males at consecutive skeletal ages from 8 to 15 years. Surgeon and practice demographic information was recorded. Univariate analysis was followed by stepwise multinominal logistic regression to control for confounders. Results: Eighty-eight of 103 surgeons (85%) responded to the survey, the majority of whom (68%) performed more than 25 pediatric ACL reconstructions annually. The greatest variation in technique was from ages 11 to 13 in females and 11 to 14 in males. The modified MacIntosh was the most frequently utilized from ages 8 to 10. An all-epiphyseal technique was preferred over a broader age range in males than females, with peak utilization at age 11 in both. A partial trans-physeal (hybrid) technique was preferred in slightly older patients, with peak utilization at age 12 in females and 13 in males. The trans-physeal technique was most widely used at age 13 and up in females and 14 and up in males. The impact of fellowship training on technique preference was statistically significant for males ages 11-13 and females 11 and 12 (p&lt;0.05 for all). Surgeons with pediatric orthopaedic training tended to prefer an all-epiphyseal reconstruction, while those with both pediatric and sports training preferred the modified MacIntosh. Conclusions: The preferred ACL reconstruction technique for skeletally immature patients varied considerably, especially in the 11-13 year-old age range, highlighting a lack of consensus among orthopedic surgeons for the optimal ACL reconstruction strategy in skeletally immature patients. Surgeon’s fellowship training was significantly associated with their preferred surgical technique.

OVER-THE-TOP VERSUS ALL-EPIPHYSEAL TECHNIQUE FOR PHYSEAL SPARING ACL RECONSTRUCTION

BACKGROUND A variety of techniques are utilized for physeal sparing ACL reconstruction, however, no clear consensus exists on the ideal surgical technique, the frequency of complications, and how to best avoid growth disturbance. The purpose of this systematic review is to compare outcomes and complications between over-the-top and all-epiphyseal ACL reconstruction techniques. METHODS The EMBASE and PubMed databases were queried for studies on ACL ruptures in the skeletally immature from 1985 to 2016. Full-text, English studies discussing operative intervention on skeletally immature patients with ACL tears were included (n = 160). Studies that reported re-rupture and/or complications after physeal sparing ACL reconstruction, specifically growth disturbance, were then included in a secondary analysis (n=10). Studies were separated into two groups: an all-epiphyseal group with femur and tibia fixation points within the epiphysis and a group that had over-the-top femur and tibia physeal-sparing reconstruction. Complications that were not specific to the pediatric population were excluded. Angular deformity greater than 3 degrees between the operative and non-operative extremities was used as the threshold. Patient demographics, evaluation of skeletal maturity and growth disturbance, graft type, surgical technique, follow up, growth disturbance, re-rupture, and patient reported outcome scores were collected. Data was analyzed in aggregate. RESULTS Ten studies were included with 280 knees in 279 patients. The average age was 11.8 years, 79% were male, and the mean post-operative follow up was 46.2 months. There were 178 patients who underwent all-epiphyseal reconstruction and 102 patients who underwent ACL reconstruction with the femoral graft placed in an over-the-top position. The overall re-rupture rate was 8.2% (23 of 280). There were 16 re-ruptures in the all-epiphyseal group (9%), and 7 re-ruptures in the over-the-top group (6.9%). Of those studies that specified treatment for re-rupture, 80% of patients required revision ACL reconstruction. Two studies did not conduct objective assessment of skeletal maturity. The majority of studies (50%) did not assess for baseline limb length inequality or angular deformity. 30% of studies performed routine hips-to-ankles bilateral lower extremity radiographs. 20% of studies assessed baseline LLD/angular deformity using clinical examination. Post-operatively, 50% of studies obtained routine hips-to-ankles lower extremity radiographs. 30% of studies obtained post-operative alignment imaging only if there was clinical suspicion of growth disturbance. There were ten total growth disturbances (3 required corrective surgery, or 30%). Seven knees developed limb overgrowth (six in the all-epiphyseal group (mean 1.8 cm) and one in the over-the-top group, 1.5 cm). Two of the patients with overgrowth from the all epiphyseal group required epiphysiodesis (28.6%). Five patients were observed. There were two angular deformities (one with 4 degrees of valgus, and another with 4 degrees varus), both in the over-the-top group which were treated with observation. There were no knees which developed angular deformity in the all epiphyseal group. One patient from the over-the-top group developed a multi-planar flexion-valgus deformity and required distal femoral osteotomy for correction. Five studies reported excellent Lysholm scores of 96.4. Six studies reported IKDC scores (range 88.5-100, 93% grade A or B). CONCLUSIONS / SIGNIFICANCE Growth disturbance after physeal sparing ACL reconstruction was overall uncommon and mild. The phenomenon of overgrowth was common likely due to younger patients receiving physeal sparing procedures. Overgrowth was more common in the all-epiphyseal group and angular deformity in the over-the-top group. Re-rupture rates were similar between the two groups. Evaluation of pre-operative skeletal maturity and comparison of baseline to post-operative growth disturbance was limited by lack of routine imaging assessment. We recommend routine PA hand radiographs, and pre- and post-operative hips-to-ankles alignment radiographs in all skeletally immature patients prior to undergoing ACL reconstruction. Further multi-center study with patient reported outcomes and long-term follow-up are necessary to determine the ideal reconstructive technique in the young, skeletally immature population.

Comparing Outcomes Between the Over-the-Top and All-Epiphyseal Techniques for Physeal-Sparing ACL Reconstruction: A Narrative Review.

A variety of techniques are used for physeal-sparing anterior cruciate ligament (ACL) reconstruction; however, there is no clear consensus on the ideal surgical technique, the frequency of complications, and how to best avoid growth disturbance. The purpose of this study was to compare outcomes and complications between over-the-top and all-epiphyseal ACL reconstruction techniques. The hypothesis was that both physeal-sparing reconstruction techniques are efficacious, with similar risk of growth disturbance and complications. The Embase and PubMed databases were queried for studies on ACL ruptures in the skeletally immature population from 1985 to 2018. Full-text English studies were included (N = 160). Studies reporting rerupture and/or complications after physeal-sparing ACL reconstruction, specifically growth disturbance, were included (n = 10). Studies were separated into 2 groups: an all-epiphyseal group with femoral and tibial fixation points within the epiphysis and a group that had over-the-top femoral and tibial physeal-sparing reconstruction. Complications not specific to the pediatric population were excluded. Demographics, evaluation of skeletal maturity, surgical technique, growth disturbance, rerupture, and patient-reported outcome scores were collected. Data were analyzed in aggregate. The 10 studies included 482 knees. The mean age was 12.0 years; 81% of patients were male; and mean follow-up was 47.7 months. A total of 178 patients underwent all-epiphyseal reconstruction, and 298 had the femoral graft placed over the top. The rerupture rate was 9.0% (16 of 178) in the all-epiphyseal group and 7.2% (14 of 195) in the over-the-top group, of which 82% required revision reconstruction. Six patients had overgrowth in the all-epiphyseal group (mean, 1.8 cm) and 1 patient in the over-the-top group (1.5 cm). Three angular deformities occurred, all of which were in the over-the-top group. Both physeal-sparing ACL reconstruction techniques are successful. Overgrowth was more common in the all-epiphyseal group and angular deformity in the over-the-top group. Rerupture rates were similar between the groups. The authors recommend standardization of skeletal age assessment and baseline lower extremity alignment films.

Le lesioni del legamento crociato anteriore del ginocchio del paziente in accrescimento

ACL injuries in prepubescent patients are being seen with increasing frequency. The reasons include intensive year round training regimens and early sport specialisation, but also a more precise diagnosis of the trauma and its causes. The traditional treatment was conservative, but with poor outcomes and an high rate of chondral and articular damages caused by prolonged instability. As a result, there is the need for surgical anterior cruciate reconstruction even in skeletally immature patients. Many surgical techniques have been described to achieve a physeal sparing reconstruction, thus avoiding iatrogenic damages of the limb growth. The proposed techniques can be divide into three groups: extra-epiphyseal, trans-epiphyseal and all-epiphyseal. Some issues are related to the non-anatomical stabilisation achieved with the extra-epiphyseal reconstruction. All-epiphyseal reconstruction, which involves some technical complexities, should be preferred in younger patients with fully open physes. The trans-epiphyseal approach has shown satisfactory outcomes in patients with older skeletal age, reducing the surgical impact on growth cartilages with some technical adjustments if compared with the usual technique for adults.

Factors Affecting the Preferred Surgical Technique in Pediatric Anterior Cruciate Ligament Reconstruction.

Background:Despite several well-described operative techniques, the optimal management of anterior cruciate ligament (ACL) injuries in pediatric patients remains unclear.Purpose:To identify surgeons’ preferred ACL reconstruction techniques and postoperative protocols for pediatric patients of various ages.Study Design:Cross-sectional study.Methods:An electronic survey was administered to surgeons in the Pediatric Research in Sports Medicine (PRiSM) society, resulting in a cohort of experienced respondents who performed a relatively high volume of ACL reconstructions in skeletally immature patients. Surgeon and practice demographic information was recorded. The survey presented the scenario of a patient who had a physical examination and imaging consistent with an acute, isolated ACL tear. The respondents were asked to select their preferred reconstruction technique for female and male patients at consecutive skeletal ages from 8 to 15 years. Surgeons were also asked about postoperative protocol.Results:Of 103 surgeons, 88 (85%) responded to the survey, the majority of whom (68%) performed more than 25 pediatric ACL reconstructions annually. The greatest variation in technique was from ages 11 to 13 years in female patients and from 11 to 14 years in male patients. The modified MacIntosh was the most frequently used technique for patients aged 8 to 10 years. An all-epiphyseal technique was preferred over a broader age range in male patients than female patients, with peak use at age 11 in both. A partial transphyseal (hybrid) technique was preferred in slightly older patients, with peak use at age 12 in female patients and 13 in male patients. The transphyseal technique was most widely used at age 13 and older in female patients and 14 and older in male patients. The impact of fellowship training (pediatrics, sports, or both) on technique preference was statistically significant for male patients aged 11 to 13 and female patients 11 and 12 (all P < .05). Surgeons with pediatric orthopaedic training tended to prefer an all-epiphyseal reconstruction, while those with both pediatric and sports medicine training preferred the modified MacIntosh.Conclusion:The preferred ACL reconstruction technique varied considerably, especially for patients aged 11 to 13 years. The modified MacIntosh reconstruction was favored in patients aged 10 years or younger, while the transphyseal technique was preferred in female patients aged 13 years and older and in male patients 14 years and older. The surgeon’s fellowship training was significantly associated with his or her preferred surgical technique.

Trends in Management and Complications of Anterior Cruciate Ligament Injuries in Pediatric Patients: A Survey of the PRiSM Society.

Anterior cruciate ligament (ACL) injuries have been recognized and treated with increasing frequency in children and adolescents. ACL reconstruction (ACLR) in skeletally immature patients has unique considerations and there is a large practice variation in the management of these injuries. The purpose of this study was to survey the members of the Pediatric Research in Sports Medicine (PRiSM) Society regarding their experience with the management and complications of pediatric ACL injuries. A 15-question survey was distributed to 71 orthopaedic members of the Pediatric Research in Sports Medicine study group. Regarding treatment of an 8-year-old child with a complete ACL tear, 53% of respondents recommended iliotibial band reconstruction, 33% recommended all-epiphyseal reconstruction, and only 3% would treat nonoperatively in a brace. In adolescent patients with 2 years of growth remaining, 47% of respondents recommended a physeal "respecting" technique, 31% recommended a physeal-sparing technique, and 19% would perform an adult-style ACLR. There were 29 new cases of growth arrest reported. This study demonstrates that there have been major changes in the trends in pediatric ACLR over the past 15 years, and the most treatment variability is found among adolescent patients with about 2 years of growth remaining. The study also demonstrates that while the overall incidence of growth disturbance after ACLR remains low, new cases of growth disturbance continue to be identified. Level V-survey of expert opinion and experience.

Sequential MRI Study of Graft Integrity and Signal Following Pediatric All-epiphyseal ACL Reconstruction: Does the “Sharp Turn” at the Socket of the Distal Femoral Aperture Matter?

Objectives:To analyze graft structure and signal with particular emphasis on the distal femoral socket aperture following all-epiphyseal ACLR using hamstring autografts with sequential MRI in skeletally immature athletes.Methods:Retrospective cohort study of 23 skeletally immature patients who underwent ACLR by the same surgical team at a tertiary center during 2011-2013. Athletes had at least two follow-up MRIs, the first MRI 6-12 months after surgery and the second MRI >18 months, were included. Exclusion criteria included those athletes with inMRI follow-up (6) or with a failure of their reconstructions (1). All athletes were treated with an arthroscopic all-inside, all-epiphyseal ACLR, using hamstring autograft, secured with adjustable loop cortical buttons on both tibia and femur. MRI images were analyzed independently and blinded by an orthopaedic surgery fellow and a musculoskeletal radiology fellow. Using a GE Functional Analysis Software, the signal intensity (SI) of the graft was measured in 5 different locations: 1) femoral tunnel, 2) intra-articular proximal turn, 3) midsubstance, 4) intra-articular distal turn, and 5) tibial tunnel. Values were normalized to cortical bone density. The amount of perigraft scarring and synovitis was analyzed. An intraclass correlation coefficient was used to quantify inter-rater reliability, non-parametric Wilcoxon test for perigraft scarring and synovitis, one-way ANOVA to test if significant differences of SI were seen between the different graft locations, and a 2-tailed student t-test for SI changes from 1st to 2nd MRI.Results:The study included 16 patients (5 girls and 11 boys), with an average age at surgery of 11.9 years (range 10-15). The first follow-up MRI was on average at 8.4 months (range 6-12 months), while the 2nd MRI was on average 30.7 months (range 18-40) after surgery. Intra-class correlation coefficients were above 0.7 for all measurements, indicating an excellent concordance between observers. Perigraft scarring tended to reduce with follow-up (p=0.057) though not significantly, while synovitis had a significant reduction over time (p=0.01). On average, normalized SI showed no significant differences between measurements taken in different regions of the graft (p=0.58). When comparing the graft SI from 1st to 2nd MRI, no significant differences were found in any of the locations: femoral tunnel (p=0.14), proximal turn (p=0.11), midsubstance (p=0,29), intra-articular distal (p=0.10), or tibial tunnel (p=0.15). All 16 athletes returned to their prior sport at the same level of performance without re-injury.Conclusion:ACL grafts in skeletally immature patients with all-epiphyseal reconstructions maintain a stable intensity signaling at long term MRI follow-up, with no significant signal reduction over time. Despite the sharp turn created at the distal femoral socket aperture in physeal-sparing reconstructions, no particular anatomic location of the graft presents significantly different signal intensity over others. This is the first sequential mri study in pediatric epiphyseal acl reconstructions demonstrating postoperative maintenance of graft integrity and graft signal.

Kinematics and Contact Stress Analysis of Pediatric Anterior Cruciate Ligament Reconstructions: Do the All-Epiphyseal and Complete Transphyseal Reconstructions Restore Anterior and Rotational Stability?

Objectives:Pediatric ACL reconstruction techniques have been described that can restore stability and contact pressures to the ACL deficient knee. The complete transphyseal (CT) reconstruction uses a more vertical graft to minimize physeal damage whereas the all-epiphyseal (AE) reconstruction uses sockets beginning at the ACL footprint and avoids the physis. The CT reconstruction may leave the knee unstable against pivot shift loads and leave contact stress abnormalities, whereas the AE may better resist rotational loads. A direct comparison of the kinematics and contact stresses after AE and CT ACL reconstructions have not been studied.Hypotheses:Both the AE and CT reconstructions will restore translational kinematics but the AE technique will better restore rotational kinematics. The AE reconstruction will more closely replicate the contact stresses of the ACL intact knee compared to the CT reconstruction because of the restoration of rotational stability.Methods:Seven fresh-frozen human cadaveric knees were tested using a robotic manipulator. Each of the specimens was tested with the intact ACL, the deficient ACL, and after each reconstruction. The AE utilized sockets oriented within the epiphysis. The CT had more central and vertical sockets in both the tibia and femur. Both reconstructions were fixed with suspensory cortical fixation devices using an all-inside technique and 10 mm diameter hamstring grafts. Reconstruction order was randomized. Anterior stability was assessed with 134N anterior force at 30, 90° of knee flexion simulating the Lachman and anterior drawer exams, respectively. The pivot shift exam was simulated by applying a combined 8 Nm and 4 Nm of abduction and internal rotation, respectively, at 15° of knee flexion. Tibiofemoral motions were recorded and mean contact stresses generated within the tibiofemoral compartments were measured using contact stress transducers. Outcomes were compared across conditions of the ACL using ANOVA and Kruskall-Wallis for normally and non-normally distributed data, respectively.Results:Both reconstructions had significantly decreased anterior translation, medial translation, and internal rotation compared to the ACL deficient knee (Figure 1) in response to loads simulating the pivot shift. However, internal rotation and medial translation remained elevated beyond intact levels following the CT reconstruction by 10.5% (P<0.05) and by 75.3% (P<0.05), respectively. During the simulated anterior drawer test at 30° and 90° of knee flexion both reconstructions restored anterior translation to that of the ACL intact knee. In response to the pivot-shift, the AE reconstruction decreased lateral posterior contact stresses compared to the ACL-deficient knee. However, following CT reconstruction, they remained elevated compared to the ACL-competent knee (P<0.05). Both reconstruction techniques offloaded the posterior aspect of the medial tibial plateau compared to the ACL deficient knee in response to anterior loading at 30 and 90° of knee flexion.Conclusion:While both AE and CT reconstructions reduced anterior translations and posteromedial contact stresses in response to an anterior load, the AE technique more effectively reduced axial rotation and posterolateral contact stresses during a simulated pivot shift exam. These findings are likely due to the more oblique orientation of the AE graft, which makes it a more effective stabilizer to rotational and medial-lateral loads.

Pediatric ACL

Intrasubstance anterior cruciate ligament (ACL) tears in skeletally immature patients are being reported with increasing frequency. Children and adolescents often are noncompliant with conservative treatment and have higher demands for knee stability than their adult counterparts. Consequently, nonsurgical or delayed surgical management has been associated with poor outcomes, including recurrent instability, increased meniscal and chondral damage, and decreased return to athletic participation. Even so, physicians often are faced with a treatment dilemma because clinical and basic science studies have demonstrated risk of limb-length discrepancy and angular deformity with ACL reconstruction. Prior to undergoing ACL reconstruction, skeletal maturity and growth potential should be determined so patients can be risk-stratified and the appropriate surgical technique can be selected. Vertical transphyseal drill tunnels have been used to decrease physeal damage and minimize the chance of growth deformity; however, these techniques result in nonanatomic ACL graft placement. Physeal sparing techniques that avoid damage to the growth plate by drilling anatomic tunnels completely within the epiphysis and have been shown to be biomechanically superior to extraarticular and modified physeal sparing procedures. These all-epiphyseal reconstruction techniques can be used to effectively and safely treat patients with significant growth remaining. Patients nearing skeletal maturity can be treated with adult type transphyseal reconstruction techniques with quadrupled hamstring autografts. When performing transphyseal ACL reconstruction in patients nearing skeletal maturity, soft-tissue grafts should be placed across the physis to minimize the risk of growth deformity.

Physeal-Sensitive MRI Analysis Shows that an All-Inside, Anterior Cruciate Ligament Reconstruction in Skeletally Immature Athletes is Safe to the Physis

Anterior cruciate ligament (ACL) reconstruction in skeletally immature patients poses a potential risk of growth disturbance due to iatrogenic physeal injury. Multiple physeal-sparing techniques have been described but none to our knowledge combine the benefits of anatomic reconstruction and socket fixation, without violation of either the femoral or tibial physis. The purpose of this study was to evaluate the safety and efficacy of an all-inside, physeal-sparing ACL reconstruction technique in skeletally immature athletes. Twenty-three skeletally immature patients (mean chronologic age 12.6 years, [range 10-15]) were prospectively evaluated following an all-inside ACL reconstruction utilizing hamstring autograft. The mean bone age (Greulich and Pyle method) was 13.5 years. There were 8 females and 15 males. Fifteen patients had an all-epiphyseal (AE) ACL reconstruction and 8 patients had a partial transphyseal (PTP) ACL reconstruction, which spared the femoral physis but crossed the tibial physis. The PTP option was reserved for patients with minimal proximal tibial growth remaining. The mean duration of residual distal femoral growth for patients in the AE group was 2.7 years compared to 1 year in the PTP group. At a mean follow-up of 12.6 months (range 6-24), graft survival, growth arrest, and the amount of physeal violation was quantified using a previously-validated model obtained from 3-D fat suppressed spoiled gradient-recalled echo (SPGR) MRI sequences. Angular deformity and leg length discrepancy were evaluated using full-length standing radiographs. Minimal post-operative tibial physeal changes were seen in 10 of 15 patients in the AE group and by definition; all patients in the PTP group. The mean area of tibial physeal disturbance (+/- SD) was 42.4 +/- 38.6 mm2 (mean 1.7% of total physeal area) in the AE group compared to 216.7 +/- 129.1 mm2 (mean 7.3% of total physeal area) in the PTP group (p = 0.003). Minimal post-operative femoral physis encroachment was seen in one case of both groups resulting in a mean physeal disturbance of 1.5%. No cases of growth arrest, tibial fracture, articular surface violation or avascular necrosis were noted on MRI in either group. Graft survival was 100% amongst the entire cohort. The mean leg length discrepancy was -0.7mm and there were no cases of angular deformity. Our data suggests all-inside ACL reconstruction is a safe and effective technique for skeletally immature athletes at short-term follow-up. Physeal-specific MRI reveals minimal growth plate disturbance following AE reconstruction relative to a PTP technique; however, both techniques reveal no evidence of significant complications.

Contact Stress and Kinematic Analysis of All-Epiphyseal and Over-the-Top Pediatric Reconstruction Techniques for the Anterior Cruciate Ligament

Background: Adult anterior cruciate ligament (ACL) reconstruction techniques may be inappropriate to treat skeletally immature patients because of the risk of physeal complications. “Physeal-sparing” reconstruction techniques exist, but their ability to restore knee stability and contact mechanics is not well understood. Purpose: (1) To assess the ability of the all-epiphyseal (AE) and over-the-top (OT) reconstruction techniques to restore knee kinematics, (2) to assess whether these reconstruction techniques decrease the high posterior contact stresses seen with ACL deficiency, and (3) to determine whether the AE or OT technique produces abnormal tibiofemoral contact stresses. Study Design: Controlled laboratory study. Methods: Ten fresh-frozen human cadaveric knees were tested using a robotic manipulator. Tibiofemoral motions were recorded with the ACL intact, after sectioning the ACL, and after both reconstructions in each of the 10 specimens. The AE technique consisted of tunnels exclusively within the epiphysis and was fixed with suspensory cortical fixation devices. The OT procedure consisted of a central and vertical tibial tunnel with an over-the-top femoral position and was fixed with staples and posts on both ends. Anterior stability was assessed with 134-N anterior force at 0°, 15°, 30°, 60°, and 90° of knee flexion. Rotational stability was assessed with combined 8 N·m and 4 N·m of abduction and internal rotation, respectively, at 5°, 15°, and 30° of knee flexion. Results: Both reconstruction techniques off-loaded the posterior aspect of the tibial plateau compared with the ACL-deficient knee in response to both anterior loads and combined moments as demonstrated by reduced contact stresses in this region at all flexion angles. Compared with the ACL-intact condition, both the AE and OT procedures had increased posteromedial contact stresses in response to anterior load at some flexion angles, and the OT technique had increased peripheral posterolateral contact stresses at 15° in response to combined moments. Neither reconstruction technique completely restored the midjoint contact stresses. Both techniques restored anterior stability at flexion angles ≤30°; however, neither restored anterior stability at 60° and 90° of flexion. Both reconstruction techniques restored coupled anterior translation under combined moments. Additionally, the AE procedure overconstrained internal rotation in response to combined moments by 12% at 15° of flexion. Conclusion: Both reconstruction techniques provide anterior and rotational stability and decrease posterior joint contact stresses compared with the ACL-deficient knee. However, neither restored the contact mechanics and kinematics of the ACL-intact knee. Clinical Relevance: Because the AE reconstruction technique has clinical advantages over the OT procedure, the results support this technique as a potential candidate for use in the skeletally immature athlete.

Dynamic Evaluation of Pivot-Shift Kinematics in Physeal-Sparing Pediatric Anterior Cruciate Ligament Reconstruction Techniques

Background: Conventional transphyseal anterior cruciate ligament (ACL) reconstruction techniques in skeletally immature patients have been questioned because of potential physeal injuries. Consequently, multiple alternative reconstruction options have been described to restore stability while sparing the physes in the skeletally immature patient. Hypothesis: All pediatric reconstruction techniques will restore knee stability to intact levels, and the knee stability index (KSI) will discriminate stability patterns between reconstruction techniques. Study Design: Controlled laboratory study. Methods: A novel mechanical pivot-shift device (MPSD) that consistently applies dynamic loads to cadaveric knees was used to study the effect of different physeal-sparing ACL reconstruction techniques on knee stability. Six adult cadaveric fresh-frozen knees were used. All knees were tested with 3 physeal-sparing reconstruction techniques: all epiphyseal (AE), transtibial over the top (TT), and iliotibial band (ITB). The MPSD was used to consistently perform a simulated pivot-shift maneuver. Tibial anterior displacement (AD), internal rotation (IR), posterior translational velocity (PTV), and external rotational velocity (ERV) were recorded using an Optotrak navigation system. The KSI (score range, 0-100; 0 = intact knee) was quantified using a regression analysis of AD, IR, PTV, and ERV. Repeated-measures analysis of variance and logistic regression were used for comparison of kinematics and derivation of KSI coefficients, respectively. Results: ACL deficiency resulted in an increase of 20% to 115% in all primary stability measures tested compared with the ACL-intact state. All reconstructions resulted in a decrease in ADmax and IRmax as well as PTVmax and ERVmax to within intact ranges, indicating that all reconstructions do improve stability compared with the ACL-deficient state. The ITB reconstruction overconstrained AD and IR by 38% and 52%, respectively. The mean (±SD) KSI for the ACL-deficient state was 61.7 ± 22.2 (range, 47-100), while the ITB reconstruction had a mean KSI of 0.82 ± 24.0 (range, −24 to 35), the TT reconstruction had a mean KSI of 13.3 ± 8.9 (range, 0.3-23), and the AE reconstruction had a mean KSI of −4.0 ± 15.2 (range, −24 to 14). The KSI was not significantly different between reconstructions, and all were significantly lower than the ACL-deficient state (P < .0001). Conclusion: Although all reconstruction techniques tested were able to partially stabilize an ACL-deficient knee, the AE reconstruction was most effective in restoring native knee kinematics under dynamic loading conditions that mimic the pivot-shift test. Clinical Relevance: This study provides orthopaedic surgeons with objective dynamic rotational data on the ability of physeal-sparing ACL reconstructions to better determine the ideal technique for ACL construction in skeletally immature patients.

All-Epiphyseal, All-Inside Anterior Cruciate Ligament Reconstruction Technique for Skeletally Immature Patients

Anterior cruciate ligament (ACL) injuries are an increasingly recognized problem in the juvenile population. Unfortunately, outcomes with conservative treatment are extremely poor. Adult reconstruction techniques are inappropriate to treat skeletally immature patients because of the risk of physeal complications, including limb-length discrepancy and angular deformities. “Physeal-sparing” reconstruction techniques exist, but their ability to restore knee stability is not well understood. We describe an all-epiphyseal ACL reconstruction for use in skeletally immature patients. This is an all-inside technique with the femoral tunnel drilled retrograde and the tibial tunnel drilled retrograde; both tunnels are entirely within the epiphysis. Fixation of the hamstring autograft is achieved with soft-tissue buttons on both the femur and tibia. We present case examples for 2 patients who underwent the all-inside, all-epiphyseal reconstruction and our postoperative rehabilitation protocol. We present a novel surgical technique for an all-inside, all-epiphyseal ACL reconstruction in skeletally immature patients.

All-epiphyseal ACL Reconstruction Improves Tibiofemoral Contact

Anterior cruciate ligament (ACL) injury alters tibiofemoral contact during function, with a posterior shift of the point of contact on the tibia. An all-epiphyseal approach to ACL reconstruction is performed in pediatric patients to improve tibiofemoral contact without disturbing the physis. The hypothesis of the study is that all-epiphyseal ACL reconstruction will shift contact anteriorly on the tibia, as compared with the ACL-deficient knee. Ten cadaver knees were tested with the ACL cut and with an all-epiphyseal reconstruction. The knees were set at multiple flexion angles (0, 15, 30, and 45 degrees) and loaded with a quadriceps force of 596 N in combination with an anterior force of 100 N, with the quadriceps loaded in isolation, and with the quadriceps loaded in combination with a hamstrings force of 200 N. Sensors under the menisci characterized the center of force on the tibia. Paired t tests were used to identify significant (P<0.05) differences between the reconstructed and cut conditions for all loading conditions at all flexion angles. On the medial plateau, the average center of force was 2 to 5 mm more anterior for the reconstructed condition than for the ACL cut, with the difference significant for all test conditions. The largest differences between the ACL conditions occurred for the combination of quadriceps forces plus an anterior force. On the lateral plateau, the anterior shift in the center of force from the ACL cut to reconstructed condition was significant for all flexion angles except 0 degree for all loading conditions, with an average difference of approximately 2 mm for all significant differences. All-epiphyseal ACL reconstruction shifts contact anteriorly on the tibia compared with the injured knee. The anterior shift of contact on the femur related to all-epiphyseal ACL reconstruction reduces changes related to ACL injury, which could reduce the risk of cartilage damage and meniscal injuries without violating the growth plate in pediatric patients.

Biomechanical Evaluation of Pediatric Anterior Cruciate Ligament Reconstruction Techniques

Background: Anterior cruciate ligament (ACL) reconstruction rates in skeletally immature patients have risen recently because of increased injury frequency combined with growing awareness of the importance of treating them in an acute setting. Concerns over potential growth disturbances caused by traditional tunnel placement have prompted the description of several partial and complete physeal-sparing techniques. Hypothesis: Native knee kinematics will most closely be restored by the all-epiphyseal technique because it best re-creates the intra-articular ACL anatomy. Study Design: Controlled laboratory study. Methods: Six cadaveric knees were subjected to static anteroposterior, varus, and internal rotation forces at 0°,15°, 30°, 45°, 60°, and 90° of flexion. Displacement and rotation of the tibia with respect to the femur were measured in the intact knee, after ACL disruption, and again after ACL reconstruction using all-epiphyseal, transtibial over-the-top, and iliotibial band physeal-sparing techniques. Results: Peak anteroposterior translation in the ACL intact and deficient states was 2.8 ± 1.4 mm and 7.2 ± 2.7 mm, respectively, at 30°. The all-epiphyseal reconstruction had a peak translation of 5.1 ± 2.3 mm at 30°, and the transtibial over-the-top reconstruction had a peak of 4.8 ± 1.8 mm at 30°, both significantly greater than the ACL intact state. The iliotibial band technique had a peak anteroposterior translation of 1.7 ± 1.1 mm at 45°, which was significantly less than the ACL-deficient state. Internal rotation was significantly increased in the all-epiphyseal reconstruction compared with the ACL intact state and significantly decreased at all flexion angles except 0° in the iliotibial band reconstruction. The only technique to affect varus rotation was the iliotibial band reconstruction, which significantly decreased varus rotation from the ACL-deficient state at flexion angles greater than 30°. Conclusion: All physeal-sparing reconstruction techniques restored some stability to the knee. The iliotibial band reconstruction best restored anteroposterior stability and rotational control, although it appeared to overconstrain the knee to rotational forces at some flexion angles. Clinical Relevance: This study provides orthopaedic surgeons with objective knee kinematic data to help guide them in making more informed decisions on the optimal technique for ACL reconstruction in skeletally immature patients.