Association Between Neuromuscular Variables and Graft Harvest in Soft Tissue Quadriceps Tendon Versus Bone–Patellar Tendon–Bone Anterior Cruciate Ligament Autografts

Background: Quadriceps tendon (QT) autografts are increasingly popular for anterior cruciate ligament reconstruction (ACLR). However, no study has compared QT autografts with bone–patellar tendon–bone (BTB) autografts regarding the electromechanical delay (EMD), the peak torque (PT), and the rate of force development (RFD) in the superficial quadriceps muscles (rectus femoris [RF], vastus medialis [VM], and vastus lateralis [VL]). Hypotheses: We hypothesized (1) there would be a significantly lower PT, lower RFD, and longer quadriceps EMD of the operative limb for the QT versus the BTB autograft; (2) the PT, the RFD, and the quadriceps EMD of the operative limb would be significantly depressed compared with those of the nonoperative limb, regardless of the surgical technique; and (3) there would be greater increases in the RF EMD than in the VM or the VL EMD. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 34 patients (age, 18-40 years), who had undergone ACLR (QT, n = 17; BTB, n = 17) at least 1 year before testing and performed 3 perceived maximal effort isometric tests, which were time synchronized with surface electromyography (EMG) on their operative and nonoperative limbs, were included in this study. EMD, PT, and RFD data were analyzed using a 2 (limb) × 2 (graft) × 3 (repetition) mixed repeated-measures analysis of variance. Results: The EMD, the PT, and the RFD were not significantly affected by graft choice. For the VL, a significant repetition × graft × limb interaction was detected for the VL EMD ( P = .027; ηp = 0.075), with repetition 3 having longer EMD than repetition 2 (mean difference [MD], 16 milliseconds; P = .039). For the RF EMD, there was a significant repetition × limb interaction ( P = .027; ηp = 0.074), with repetition 3 being significantly longer on the operative versus the nonoperative limb (MD, 24 milliseconds; P = .004). Further, the operative limb EMD was significantly longer for repetition 3 versus repetition 2 (MD, 17 milliseconds; P = .042). For the PT, there was a significant effect for repetition ( P = .003; ηp = 0.114), with repetition 1 being significantly higher than both repetitions 2 (MD, 8.52 N·m; P = .001) and 3 (MD, 7.79 N·m; P = .031). For the RFD, significant limb ( P = .034; ηp = 0.092) and repetition ( P = .010; ηp = 0.093) effects were seen, with the nonoperative limb being significantly faster than the operative limb (MD, 23.7 N·m/s; P = .034) and repetition 1 being significantly slower than repetitions 2 (MD, -20.46 N·m/s; P = .039) or 3 (MD, −29.85 N·m/s; P = .002). Conclusion: The EMD, the PT, and the RFD were not significantly affected by graft type when comparing QT and BTB autografts for ACLR; however, all neuromuscular variables were affected regardless of the QT or the BTB harvest.

ESTIMATED PERFORMANCE FOR AGE: A NOVEL CRITERION FOR RETURN TO SPORT AFTER ANTERIOR CRUCIATE RECONSTRUCTION AND ITS PERFORMANCE COMPARED TO LIMB SYMMETRY INDICES

INTRODUCTION: The use of physical performance tests (PPT) for assessing readiness for return to sport (RTS) after ACL reconstruction in children is typically assessed based on a limb symmetry index (LSI). However, recent data show that: 1) healthy pediatric athletes have significant limb asymmetries at baseline and 2) the non-operative limb deconditions after ACLR, so return of LSI is not synonymous with return to pre-injury performance. We previously established a cohort of 100 healthy pediatric athletes and created growth curves for performance on 7 common PPT, allowing for the calculation of a performance percentile (PP) for any given individual based on their age. The current study explores the use of PP in a cohort of pediatric patients 6 months out from ACLR. We hypothesized that return to expected performance for age (EPFA, defined as the 50th percentile of performance among healthy volunteers of a given age) would be a more stringent criterion than 90% LSI. METHODS: We performed a retrospective analysis of a prospective cohort of consecutive patients (< 19 years) undergoing ACL reconstruction between 2016-2019. Patients were excluded if they did not have RTS testing 6 months after surgery (+/- 6 weeks). RTS testing consisted of 7 PPT (Figure 1). Patients were then categorized into passing and failing groups based on two cutoffs: 1) LSI > 90% and 2) PP > EPFA (50th percentile). The prevalence of passing based on these two criteria were compared using contingency analysis. A multivariable linear regression was performed to assess the effects of demographic variables on PP. RESULTS: Sixty-three patients were included (57% male, mean age 14.2 ± 2.4 years). Mean time from surgery to RTS testing was 181.5 ± 15.1 days. More patients were able to achieve 90% LSI than EPFA for all PPT except the timed hop (Figure 1). On average, 58% met LSI > 90% compared to only 41% meeting EPFA. Reaching 90% LSI correlated weakly with reaching EPFA for 4 of the 7 PPTs. However, of patients that would have passed based LSI, only 36.2-63.2% would have passed based on meeting EPFA (Figure 2). There was no consistent effect of age, sex, or graft type on PP. CONCLUSION: Six months after ACL reconstruction, fewer pediatric athletes can meet EPFA than can meet 90% LSI. Additionally, PP does not clearly correlate with LSI, suggesting that these criteria provide complementary information. Future studies investigating the use of EPFA as a cutoff for RTS are warranted. [Figure: see text][Figure: see text]

Sex-Specific Difference in Dynamic Balance Following Total Hip Replacement

Background and Objectives Total hip replacement (THA) is a common surgical procedure in older adults (65 years or older). THA has high patient satisfaction, but little is known about balance and mobility limitations after surgery and if outcomes are sex-specific. To evaluate post-THA asymmetry during unilateral standing and a dynamic balance and reach test and test the hypotheses that balance performance would be decreased on the surgical limb and that balance deficits would be greater in women than men. Research Design and Methods Primary, unilateral THA (70 male, 57 female) patients completed a bilateral 10-second single leg stance test. Sixty male but only 34 female participants could maintain unilateral balance for 10 seconds or greater. The cohort who successfully completed the 10-second single limb stance test then completed a Lower Quarter Y-Balance Test (YBT-LQ) in which the maximum anterior (ANT), posteromedial (PM) and posterolateral (PL) reach distances were obtained bilaterally and used to calculate the asymmetry score. All variables were compared using a mixed-model repeated-measures ANOVA (sex by limb), while independent samples t-tests were used to assess sex-specific asymmetry. Results Women failed single leg stance at a higher rate than men (85.7% vs. 59.6%; p=0.001). Reach distance was different between limbs for all reach directions (p&lt;0.004) with greater reach distance on the non-operative limb for all patients. Men had a greater reach distance in the ANT (p=0.004), and PM (p=0.006) directions. Discussion and Implications These results indicate that post-THA the operative limb and female patients have greater balance limitations. These results are novel and reveal sex-specific patterns that emphasize the need for sex-specific post-operative rehabilitation programs to improve long-term outcomes, especially in older adults with muscle weakness and balance deficits.

Pre- and Post-Operative Limb Symmetry Indexes and Estimated Preinjury Capacity Index of Muscle Strength as Predictive Factors for the Risk of ACL Reinjury: A Retrospective Cohort Study of Athletes after ACLR

Long-term muscle weakness may increase the risk of knee reinjury after anterior cruciate ligament reconstruction (ACLR) and of osteoarthritis. The incidence of secondary injuries after ACLR and the predictive value of preoperative and postoperative limb symmetry index (LSI) and estimated preinjury capacity (EPIC) index were studied for predicting the risk of reinjury in a retrospective study. Sixty-three recreational and professional athletes after ACLR with hamstring autograft were followed for secondary injury in the period from 2012 to 2014, 5 years after ACLR. Peak torque values of knee extensor and flexor muscle strength of the involved and uninvolved limb were measured with an isokinetic dynamometer at 60 degrees per second before ACLR and 6 months after ACLR and were used to calculate LSI and EPIC index. The results suggest that the preoperative LSI and EPIC indexes predict a secondary ACL injury better than the postoperative LSI for extensor muscles which is often used as a criterion to determine the time for returning to normal sports activities. Individuals with secondary ACL injuries suffer greater loss of knee extensor muscle strength of the uninvolved limb between preoperative and postoperative ACLR testing compared to the individuals without secondary injury.

Single-Leg Squat After Anterior Cruciate Ligament Reconstruction: An Analysis of the Knee Valgus Angle at 6 and 12 Months

Background: Deficits in neuromuscular control are common after anterior cruciate ligament (ACL) reconstruction and may be associated with further knee injury. The knee valgus angle during a single-leg squat (SLS) is one measure of neuromuscular performance. Purpose: To determine whether the knee valgus angle during SLS changes between 6 and 12 months after ACL reconstruction and to assess how the operative knee valgus angle compares with that of the contralateral side. Study Design: Case series; Level of evidence, 4. Methods: A cohort of 100 patients with uninjured contralateral knees were assessed at 6 and 12 months after primary hamstring autograft ACL reconstruction. Participants performed the SLS on each leg, and the knee valgus angle was measured via frame-by-frame video analysis at 30° of flexion and at each patient’s maximum knee flexion angle. Results: For the operative limb at 30° of flexion, a small but statistically significant reduction was noted in the valgus angle between 6 and 12 months (5.46° vs 4.44°; P = .002; effect size = 0.24). At 6 months, a slightly higher valgus angle was seen in the operative limb compared with the nonoperative limb (5.46° vs 4.29°; P = .008; effect size = 0.27). At maximum flexion, no difference was seen between limbs in the valgus angle at either 6 or 12 months, and no change was seen in the operative limb between 6 and 12 months. At 6 months and 30° of knee flexion, 13 patients had a valgus angle greater than 10°. This group also had a higher mean valgus angle in the contralateral limb compared with the contralateral limb in the other 87 patients (8.5° vs 3.65°; P < .001). Conclusion: During a controlled SLS, the knee valgus angle remained essentially constant, and minimal limb asymmetries were present over the 6- to 12-month postoperative period, a time when athletes typically increase their activity levels. Whether changes or asymmetries will be seen with more dynamically challenging tasks remains to be determined. When present, high valgus angles were commonly bilateral.

Femoral Tunnel Fixation for Medial Patellofemoral Ligament Reconstruction in the Growing Patient is Safe for Future Growth

Objectives: Medial patellofemoral ligament (MPFL) reconstruction has been shown to be a successful treatment for patients with recurrent patellar instability and is increasingly used to treat skeletally immature patients. The purpose of this study is to compare radiographic parameters prior to and following an MPFL reconstruction with femoral tunnel fixation in the skeletally immature patient to investigate potential effects on the physis and future growth. Methods: Skeletally immature patients undergoing isolated MPFL reconstruction were retrospectively reviewed. Fixation of proximal MPFL was performed as a femoral socket using Schottle’s point with the entry approximately 5 mm distal to the physis. Patients with open growth plates and 1-year postoperative standing alignments were included. Radiographic measures of patellar tilt, patellar height, patellar subluxation, and trochlear dysplasia were compared pre-operatively and post-operatively on the operative limb. Pre- and post-operative coronal alignment and limb length measurements were compared between the operative and non-operative limbs. Results: Nineteen skeletally immature patients with an average age of 11.6 years (range 5-15 years old) underwent isolated MPFL reconstruction. The average follow-up time was 24 months. No significant differences were found between the change in femur (0.49 mm, p=0.526) or total limb length (1.08 mm, p=0.241) when comparing the operative to the non-operative limb, with an average of 47 mm of growth in the operative limb seen during the time period. There was no significant difference in the change in LDFA between operative and non-operative limb as well as symmetric changes noted in the mechanical axis. The change in patellar tilt on the operative limb was found to be significant (12.78°, p=0.030), and the change in patellar height by Caton-Deschamps approached significance (0.08mm, p= 0.077). No significant difference was found with trochlear dysplasia measures. Conclusion: The present study suggests MPFL reconstruction with femoral tunnel fixation is safe and does not result in growth disturbance in skeletally immature patients. [Table: see text]

6-MONTH RETURN TO SPORTS TESTING FOLLOWING ACL RECONSTRUCTION IN ADOLESCENTS WITH QUADRICEPS TENDON AUTOGRAFT VERSUS HAMSTRING AUTOGRAFT

Background: Quadriceps tendon autograft represents an increasingly popular graft option for ACL reconstruction (ACLR). However, there is a paucity of literature regarding the early post-operative effects of this graft technique on functional recovery, particularly in adolescents. Purpose/Hypothesis: To quantify post-operative strength, dynamic balance, and functional hop test performance in adolescents 6 months following ACLR with a quadriceps tendon autograft (ACLR-Q) and compare to an adolescent control group who underwent ACLR with hamstring autograft (ACLR-HS). Methods: Patients 12-19 years-old who underwent primary ACLR-Q from 2017-2019 by a single surgeon at a pediatric tertiary care hospital and performed return to sports (RTS) assessments between 5-9 months post-operatively were included. Exclusion criteria were prior ipsilateral or contralateral ACLR and concomitant procedures other than meniscal repair or meniscectomy. RTS tests included manual muscle testing of strength (hamstring, quadriceps, hip abductor), dynamic-Y-balance, and functional hop tests (single-hop, triple-hop, crossover, 6-meter timed hop). Limb Symmetry Index (LSI) was calculated for all measures and each was compared with an ACLR-HS control group using T-tests. One-way between-group multivariate analysis of covariance (MANCOVA) was utilized to control for any baseline differences. Results: There were no significant differences in age, BMI, sex, or rates of meniscal procedures between cohorts (Table 1). The small difference in time of RTS testing was controlled by MANCOVA model. ACLR-Q patients demonstrated a significantly smaller hamstring strength deficit (-3.6%) than the ACLR-HS group (-35.8%, p<0.001, Table 2). The ACLR-Q group showed a significantly greater deficit in quadriceps strength (-11.9% vs. 0.9%, p<0.001). Hamstring-to-quadriceps strength ratios (HS:Q) were lower in the ACLR-HS (operative limb: 0.34 +/- 0.13, non-operative limb: 0.52 +/- 0.01) than the ACLR-Q group (operative limb: 0.61 +/- 0.16, non-operative limb: 0.56 +/- 0.12). Deficits in anterior reach, composite Y-balance score, cross-over hop, timed hop, and single hop were significantly greater in the ACLR-Q group. The deficit in 6-meter timed hop was significantly greater in the ACLR-HS group. Conclusion: Quadriceps strength deficits were greater in adolescents undergoing ACLR-Q (LSI of approximately -12%), while hamstring strength deficits were greater in adolescents undergoing ACLR-HS (LSI of approximately -33%). Hamstring-to-quad ratios were greater in the ACLR-Q patients’ operative knees than their nonoperative knees, while they were significantly lower in the ACLR-HS patients’ operative knee than their nonoperative knees. Hop testing performance was mixed between the 2 graft cohorts. The degree to which these performance metrics influence eventual athletic performance and graft-retear remains a critical area of continued investigation. [Table: see text][Table: see text]

FEMORAL TUNNEL FIXATION FOR MEDIAL PATELLOFEMORAL LIGAMENT RECONSTRUCTION IN THE GROWING PATIENT IS SAFE FOR FUTURE GROWTH

Background: Medial patellofemoral ligament (MPFL) reconstruction has been shown to be a successful treatment for patients with recurrent patellar instability and is increasingly used to treat skeletally immature patients. Purpose: The purpose of this study is to compare radiographic parameters prior to and following an MPFL reconstruction with femoral tunnel fixation in the skeletally immature patient to investigate potential effects on the physis and future growth. Methods: Skeletally immature patients undergoing isolated MPFL reconstruction were retrospectively reviewed. Fixation of proximal MPFL was performed as a femoral socket using Schottle’s point with the entry approximately 5 mm distal to the physis (Figure 1). Patients with open growth plates and 1-year post-operative standing alignments were included. Radiographic measures of patellar tilt, patellar height, patellar subluxation, and trochlear dysplasia were compared pre-operatively and post-operatively on the operative limb. Pre- and post-operative coronal alignment and limb length measurements were compared between the operative and non-operative limbs. Results: Nineteen skeletally immature patients with an average age of 11.6 years (range 5-15) underwent isolated MPFL reconstruction. The average follow-up time was 24 months. No significant differences were found between the change in femur (0.49 mm, p=0.526) or total limb length (1.08 mm, p=0.241) when comparing the operative to the non-operative limb, with an average of 47 mm of growth in the operative limb seen during the time period. There was no significant difference in the change in LDFA between operative and non-operative limb as well as symmetric changes noted in the mechanical axis. The change in patellar tilt on the operative limb was found to be significant (12.78°, p=0.030), and the change in patellar height by Caton-Deschamps approached significance (0.08mm, p= 0.077). No significant difference was found with trochlear dysplasia measures. Conclusion: The present study suggests MPFL reconstruction with femoral tunnel fixation is safe and does not result in growth disturbance in skeletally immature patients. [Figure: see text]

Inter and Intra-Rater Reliability of Using Computed Tomography to Assess Prosthesis Position Post Shoulder Arthroplasty

Background Computer models and cadaveric studies have demonstrated that humeral version has a significant impact on the impingement, stability, and range of motion of the prosthetic shoulder joint. Computed tomography (CT) has been used to measure native humeral version, however the reliability of using CT to measure humeral version post reverse total shoulder replacement has not yet been established. Aims To investigate the inter and intra-rater reliability of using CT to assess the post-operative humeral version following shoulder arthroplasty. Methodology Patients underwent a limited CT scan of the operative limb; positioned and protocoled by one consultant radiologist on one machine. The humeral version of the prostheses was calculated individually by two experienced, board certified consultant radiologists. They were blinded to each other’s measurements. The humeral version was calculated using the epicondylar axis. Data Overall, 20 shoulders are included; 12 females (60%), and 10 left-sided (50%). The median anteversion was 0° (range 33° retroversion–27° anteversion; IQ 6.75° retroversion–4.75° anteversion). The inter-rater reliability was 0.985 (95% CI: 0.964–0.994). The intra-rater reliability for radiologist A was 0.988 (95% CI: 0.969–0.995), and the intra-rater reliability for radiologist B was 0.976 (95% CI: 0.942–0.991). Conclusion The use of post operative CT has excellent inter and intra-rater reliability in measuring humeral version following shoulder arthroplasty. This study will facilitate future research regarding impact of the humeral version on patient outcomes.