Kang, Louis S

Background: The limb symmetry index (LSI) is a measure comparing strength and functional movement between the surgical and nonsurgical limbs, used after anterior cruciate ligament reconstruction (ACLR) to guide rehabilitation and assess return-to-sport readiness. With increasing use of the quadriceps tendon autograft (QT-ACLR), limited data exist on whether the LSI score correlates with patient-reported outcome measures (PROMs). Hypothesis/Purpose: To evaluate the predictive value of postoperative strength and functional LSI tests at 3, 6, and 9 months for short-term PROMs, determine Patient Acceptable Symptom State (PASS) thresholds, and assess differences based on PASS achievement. It was hypothesized that quadriceps strength LSI score would more strongly predict 2-year PROMs than hamstring strength LSI score, and that higher 9-month isokinetic quadriceps LSI scores would be associated with higher International Knee Documentation Committee (IKDC) and Lysholm scores. Study Design: Case series; Level of evidence, 4. Methods: Patients undergoing primary QT-ACLR from 2021 to 2024 with LSI testing during rehabilitation (isometric and isokinetic lower extremity strength, Y-Balance, hop testing) and no revision or additional knee surgery were included. The LSI score was assessed at 3, 6, and 9 months, and PROMs, including Lysholm and IKDC scores, were collected at a mean follow-up of 2.0 ± 0.7 years. Multivariable linear regression was used to evaluate associations between LSI measures and PROMs after adjusting for age, sex, and body mass index (BMI). Receiver operating characteristic analysis was used to determine PASS thresholds. Results: A total of 100 knees in 100 patients (mean age, 25.3 ± 11.2 years; BMI, 25.9 ± 6.5 kg/m 2 ; 52% male) were included. Quadriceps and hamstring strength and functional performance progressively improved from 3 to 9 months, with the LSI score reaching 77% to 81% for quadriceps strength and 98% to 100% for hamstring strength by 9 months postoperatively. At a mean follow-up of 2.0 ± 0.7 years, the mean satisfaction score was 8.4 of 10, the Lysholm score was 90.7, and the IKDC score was 77.8. Linear regression, adjusted for age, sex, and BMI, demonstrated that 3-month isometric quadriceps LSI score had a strong effect on IKDC score, explaining substantial variance (β = 3.9; adjusted R 2 [Adj R 2 ] = 0.36; P < .03); 6-month isokinetic quadriceps and hamstrings showed moderate but significant effects (β = 2.9-3.7; Adj R 2 = 0.13-0.17; P < .05) on IKDC score; and 9-month fast quadriceps had a strong effect explaining substantial variance in Lysholm and IKDC scores (β = 3.9-4.7; Adj R 2 = 0.34-0.35; P ≤ .003). Lysholm and IKDC scores correlated with satisfaction and accurately discriminated PASS thresholds (area under the curve, 0.927-0.937; P < .001). Patients achieving the IKDC PASS demonstrated higher LSI scores across time points and all PROMs. Conclusion: After QT-ACLR, strength-associated LSIs were independently associated with PROMs at a mean 2-year follow-up, after adjusting for age, sex, and BMI. Early isometric quadriceps strength at 3 months predicted higher 2-year IKDC scores, with PASS achievers generally attaining a 60% to 70% LSI score by 3 months. Isokinetic quadriceps strength at 9 months predicted both IKDC and Lysholm scores. These findings highlight the importance of early quadriceps strength recovery and the value of LSI measures in predicting PROMs and informing early rehabilitation.

Purpose To assess the reliability, predictability, and discriminative capacity of 3 anatomic measurements, tibial tubercle‐trochlear groove (TT‐TG), tibial tubercle‐posterior cruciate ligament, and patellar tendon‐lateral trochlear ridge (PT‐LTR), where PT‐LTR may offer a complementary approach to assessing recurrent patellofemoral instability (PFI) risk. Methods Patients diagnosed with PFI before primary patellofemoral stabilization surgery at a single institution between 2022 and 2024 were included. A control group without PFI was propensity matched 1:1 for age, sex, and laterality. Magnetic resonance images were evaluated to measure TT‐TG, tibial tubercle‐posterior cruciate ligament, and PT‐LTR. A priori power analysis determined the cohort size. Statistical analyses compared differences between the PFI and control groups with Student t‐tests, receiver operating characteristic analyses, and area under the curve with resultant sensitivity, specificity, and an optimal cutoff. Results Patients included 50 knees with PFI (28 women, 22 men; mean age 18 ± 5 years). The control group included 50 knees (27 women, 23 men; mean age 18 ± 4 years). Excellent inter‐ and intra‐rater reliability (intraclass correlation coefficient > 0.7) was shown for TT‐TG and PT‐LTR in the PFI and control groups. The distances for TT‐TG, tibial tubercle‐posterior cruciate ligament, and PT‐LTR were significant predictors ( P ≤ .025) of PFI. The average PT‐LTR distance difference for the PFI and control groups was 7.0 mm ( P < .001). PT‐LTR showed an area under the curve of 0.80 and, when ≥4.6 mm, was 66% sensitive and 92% specific for PFI. Conclusions The PT‐LTR distance is a reliable and discriminative metric for identifying PFI in both pediatric and adult populations. A PT‐LTR cutoff value of 4.6 mm showed diagnostic discrimination and substantially high specificity for recurrent PFI, indicating strong ability to identify patients with instability. Level of Evidence Level III, retrospective case control study.

Purpose To evaluate implantation rates, time to implantation, and predictors of implantation following matrix‐induced autologous chondrocyte implantation (MACI) biopsy for knee chondral defects. Methods Patients undergoing MACI biopsy or implantation for symptomatic knee chondral defects from 2017 to 2024 at a single institution were reviewed. At a minimum 1‐year follow‐up, the decision to proceed with implantation, recurrent symptoms, complications, and reoperations were assessed. Kaplan‐Meier analysis estimated time to implantation, and multivariable logistic regression identified predictors of MACI implantation. Results A total of 208 knees in 202 patients (mean age 28.0 ± 10.9 years, range 11‐59) underwent MACI biopsy for 243 chondral defects (patella [38%], femoral condyle [34%], and trochlea [26%]). At a mean follow‐up of 4.3 years (range 1.0‐8.3), 64 knees (31%) proceeded to second‐stage MACI implantation. Among 144 knees not implanted, 87 (60%) reported symptom improvement, and 26 (18%) had persistent symptoms. The remaining 22% did not undergo implantation due to another cartilage procedure, insurance denial, or pending scheduling. Patients who underwent biopsy at the home institution had a shorter time from biopsy to implantation compared with those biopsied at outside institutions (6.1 vs 13.1 months, P = .001). Median time to implantation was 9.4 months (95% confidence level: 7.2‐12.2) for home biopsies. Lower body mass index was associated with progression to implantation after adjusting for covariates (odds ratios 0.92, P = .019). Patients implanted within 4 months had larger chondral defects (4.0 vs 3.0 cm 2 , P = .045). At a mean 4.1‐year follow‐up, 6 patients (8%) experienced postoperative complications, including 3 (4%) who required revision chondroplasty. Conclusions MACI biopsy for knee chondral defects resulted in approximately one‐third of patients proceeding to MACI implantation, at a median of 9.4 months after biopsy. Lower body mass index was associated with higher likelihood of progression to implantation, larger chondral defects with earlier implantation, and among patients who did not proceed to implantation, approximately 60% reported symptom improvement following concomitant chondroplasty at the time of biopsy. Level of Evidence Level IV, retrospective case series.

Purpose To evaluate return‐to‐sport (RTS) rates and patient‐reported outcome measures (PROMs) following hip arthroscopic labral repair for femoroacetabular impingement in active basketball players with a minimum of 2‐year follow‐up. Methods All patients who were active basketball players and underwent hip arthroscopy with labral repair for femoroacetabular impingement from 2009 to 2022 were identified. Patients were evaluated for postoperative RTS and revision surgery at a minimum 2‐year follow‐up. RTS was defined as resuming basketball participation, at any level. Modified Harris Hip Score (mHHS), Hip Outcome Score‐Activities of Daily Living (HOS‐ADL) and Sport (HOS‐Sport), and surgery satisfaction were also collected. Results Sixty‐seven hips in 54 athletes (29 male, 25 female) with a mean age of 22.2 years (range 13‐39 years) were included. Eighty‐six (86%) were recreational or high school basketball players. There was significant improvement in all PROMs from baseline to a minimum 2‐year follow‐up (all P < .001). After excluding for athletes who did not RTS for nonmedical reasons, 78% of athletes returned to basketball following hip arthroscopy. Including patients who cited nonmedical reasons for not returning, the overall RTS rate was 65%. Athletes who RTS had significantly higher mHHS ( P = .012), HOS‐ADL ( P = .006), and HOS‐Sport ( P = .002), as well as lower visual analog scale pain (2.2 vs 3.4, P = .037) than those who did not RTS. Calculated minimal clinically important difference values were 8.3 for mHHS, 7.2 for HOS‐ADL, and 13.4 for HOS‐Sport. Anchor‐based patient acceptable symptom state calculations yielded thresholds of 83.5 for mHHS, 92.6 for HOS‐ADL, and 79.2 for HOS‐Sport—with 70%, 63%, and 67% of patients achieving these thresholds, respectively. Conclusions Basketball players who undergo hip arthroscopic labral repair for femoroacetabular impingement show significant improvements in PROMs with 78% RTS rate at a minimum 2‐year follow‐up. Although many athletes discontinued basketball for reasons unrelated to the hip, 18% cited hip issues. Basketball players who successfully return to basketball report higher PROMs than nonreturners, and cohort‐specific minimal clinically important difference analysis indicates that most athletes achieve clinically meaningful improvements. Level of Evidence Level IV, therapeutic retrospective case series.

Purpose To investigate outcomes among patients undergoing total hip arthroplasty after hip arthroscopy (HA‐THA) compared with a matched cohort undergoing primary THA without prior arthroscopy (Only‐THA). Methods Patients who underwent THA after primary hip arthroscopic labral repair from 2009 to 2022 at a single institution were identified. Cases were propensity‐matched 1:4 to primary THA controls by age at THA, sex, body mass index (BMI), surgical approach, and year of surgery. At minimum 2‐year follow‐up, patient‐reported outcomes (PROs)—Forgotten Joint Score (FJS), modified Harris Hip Score (mHHS), and Hip Disability and Osteoarthritis Outcome Score Pain (HOOS‐Pain)—were analyzed. Results Sixty‐two hips (age: 47.5 ± 9.3 years, BMI: 29.7 ± 6.2 kg/m 2 ) were matched to 248 Only‐THA hips (age: 47.9 ± 10 years, BMI: 29.5 ± 5.8 kg/m 2 ). Although both HA‐THA and Only‐THA patients showed significant ( P < .001) postoperative improvements in PROs, HA‐THA patients reported significantly lower postoperative FJS, mHHS, HOOS‐Pain, and inferior Visual Analog Scale pain scores ( P < .001) compared with Only‐THA controls. A cohort‐specific minimal clinical important difference for mHHS was calculated as 9.6 points, with 75.7% of HA‐THA and 87.5% Only‐THA patients achieving this threshold ( P = . 077). At mean 6.6 ± 3.3 years follow‐up, HA‐THA patients with preoperative Tönnis grades 1 reported significantly decreased FJS, mHHS, and HOOS‐Pain compared with HA‐THA patients with preoperative Tönnis grade 2‐3 ( P ≤ .05). HA‐THA patients with Tönnis grade 1 also exhibited worse PROs ( P < .001) compared with Only‐THA controls. Although there were no differences in complication rates between HA‐THA and Only‐THA patients (8% vs. 5%, P = .49), all‐cause reoperation was greater amongst HA‐THA (10% vs. 2%, P = .01). Conclusions Patients undergoing THA after prior hip arthroscopy showed modestly inferior subjective outcomes at mid‐term follow up compared with an age‐matched cohort without prior arthroscopy. Although both groups showed meaningful improvement, a smaller proportion of HA‐THA patients achieved the cohort‐specific MCID for mHHS compared with Only‐THA controls. Level of Evidence Level III, retrospective cohort study.

Background: Acetabular overcoverage (pincer morphology) has been suggested to be both a source of pain and dysfunction and potentially protective against osteoarthritic change. Purpose: To compare the minimum 5-year clinical outcomes of patients undergoing primary hip arthroscopic labral repair with a lateral center edge angle (LCEA) of ≥40° as compared with nondysplastic controls with an LCEA of 25° to 40°. Study Design: Cohort study; Level of evidence, 3. Methods: A retrospective review was performed to identify all patients who underwent primary hip arthroscopic labral repair between 2009 and 2019 at a single academic institution. Patients with an LCEA of ≥40° (pincer) were propensity-matched to nondysplastic controls with an LCEA of 25° to 40° on a 1-to-2 basis by sex, age, body mass index, and surgery year. Patient-reported outcome measures (PROMs)—including visual analog scale, Tegner activity score, modified Harris Hip Score, International Hip Outcome Tool (iHOT-12), and Hip Outcome Score were analyzed—as were reoperations and conversions to total hip arthroplasty (THA). Results: A total of 55 patients with pincer morphology (preoperative LCEA: 41.9°± 2.1°) were matched to 110 nondysplastic controls (LCEA: 31.2°± 4.1°), resulting in a total of 165 hips in 163 patients (67% women, mean age: 37.7 ± 9 years). Pincer patients were corrected to a mean postoperative LCEA of 38.7°± 4.1º ( P < .001), with 22 pincer patients having residual overcoverage; namely, a postoperative LCEA ≥40° (range, 40°-45.8°). There were no differences between cohorts regarding intraoperative characteristics—including femoral and acetabular Outerbridge grade—as well as capsulotomy type and the presence of capsular repair ( P ≥ .210). At a mean 8-year follow-up (range, 5.1-13.2), there was no difference in any postoperative PROMs between pincers and controls ( P ≥ .215) and no difference in PROMs between patients with residual overcoverage and pincer patients with a postoperatively normalized LCEA ( P ≥ .291). At final follow-up, 4 patients in the pincer cohort (7%) and 21 controls (19%) converted to THA ( P = .046). Conclusion: Patients with lateral acetabular overcoverage demonstrated similar and satisfactory postoperative PROMs at a minimum 5-year follow-up compared with propensity-matched nondysplastic controls, regardless of whether the LCEA was corrected to <40°. Of note, nondysplastic controls demonstrated a higher rate of conversion to THA, suggesting a potentially chondroprotective role for acetabular overcoverage.

Purpose To use publicly available injured list (IL) data to 1) describe Major League Baseball injury trends from 2010 to 2024; 2) analyze injury types and body regions affected to report the highest impact injuries; and 3) report the financial implications of time lost due to injury over this 15‐year period. Methods IL data for every Major League Baseball player (pitchers and position players) from the 2010 to 2024 regular seasons were collected using publicly available sources, including player demographics, IL placements, body part injured, and length of each IL stay. Player salaries were compiled to determine the “financial loss” per injury. Results Across 15 seasons, 8078 players were placed on the IL, totaling 478,085 days. The mean IL placements/year was 634, and the annual number increased by an additional 27 injuries/year ( P < .001). Mean total IL days/season was 31,872, and this increased year‐over‐year ( P = .008). Shoulder injuries represented the most IL placements (n = 1555), followed by elbow (n = 1344) and upper leg (n = 769). Elbow injuries averaged the most days missed/IL placement (mean: 93, median: 74) and the greatest total days missed (129,610), followed by shoulder (95,189). Pitchers comprised 55% of IL placements and most commonly injured their shoulder or elbow. Infielders and outfielders accounted for 21% and 16% of IL placements, respectively. A total financial loss of $9,636,753,291 was accumulated over 15 seasons. Financial loss increased season‐to‐season (+$32,309,178/year, P = .002). Elbow injuries accounted for the highest financial loss at $1,932,048,168 ($1,379,049 lost/injury). In 2024, $2,220,432 was lost/elbow injury, $1,110,573/shoulder injury, $1,397,322/any injury, and $952,973,760 total for the season. Conclusions This study observed that the number of players, IL placements, days spent on the IL, and financial loss due to injury increased steadily each year. Pitchers were the most frequently injured players with shoulder and elbow injuries being most common. Over the 15‐season study period, there was a total financial loss of nearly $9.7 billion due to salary paid to injured players, with elbow injuries contributing the highest loss at just under $2 billion. Clinical Relevance Injury trends and financial data from Major League Baseball highlight the growing burden of shoulder and elbow injuries, particularly in pitchers. These findings underscore the need for orthopaedic surgeons to focus on prevention, early intervention, and optimized surgical management of high‐impact injuries to reduce long‐term morbidity and associated financial costs at the elite level.

Background: Frequent pivoting, rotation, and deep hip flexion place football players at high risk for femoroacetabular impingement (FAI), a leading cause of hip pain in this population. Previous studies have primarily focused on professional National Football League athletes undergoing mixed surgical techniques, including labral debridement. Limited data exist on outcomes in younger, amateur players treated with labral repair. Purpose: To report return to sport (RTS) rates and functional outcomes at a minimum 5-year follow-up in primarily active high school and college football players undergoing primary hip arthroscopy with labral repair for FAI. Study Design: Case series, Level of evidence, 4. Methods: All football players who underwent primary hip arthroscopy with labral repair for FAI between 2010 and 2019 were identified from an institutional database. Collected data included descriptive data, radiographic parameters, surgical details, and reoperations. At a minimum 5-year follow-up, RTS outcomes and patient-reported outcome measures (PROMs), such as the Modified Harris Hip Score (mHHS) and Hip Outcome Score (HOS), were evaluated. Results: A total of 36 hips in 27 male athletes (mean age, 18 years; body mass index, 28.1 kg/m 2 ) were included. The majority of athletes competed at the high school (70%) or collegiate level (26%). Mean preoperative radiographic measurements were as follows: lateral center-edge angle, 31.6°; Tönnis angle, 4.1°; and alpha angle, 61.4°. Femoroplasty and acetabuloplasty were performed in 100% and 86% of cases, respectively. Also, 84% of players returned to football, all at the same or higher level than before surgery. At a mean follow-up of 9.8 years, all PROMs improved significantly from baseline ( P < .002). Outcome scores at follow-up were as follows: mHHS 90.5; HOS-Activities of Daily Living, 94.5; HOS-Sports-Specific Subscale, 91.1; and visual analog scale (VAS) pain with use, 2.3/10; VAS pain at rest, 1.3/10; and surgical satisfaction, 8.5/10. No patients required revision surgery. However, 2 patients (7%) underwent reoperations—including 1 for heterotopic ossification excision and 1 for periacetabular osteotomy. Conclusion: American football players who underwent primary hip arthroscopy with labral repair for FAI achieved excellent long-term outcomes, with high RTS rates at the same or higher levels, and improvements in PROMs and patient satisfaction. Despite favorable outcomes, nonmedical factors, such as graduation, may influence RTS in competitive athletes, particularly at the high school and collegiate levels.

Background: Femoroacetabular impingement (FAI) is a common cause of hip pain in young, active athletes. American football players place high demands on the hip due to the sport's requirements for pivoting, cutting, and loading in deep flexion. Although arthroscopic treatment of FAI in professional National Football League (NFL) players has shown favorable outcomes, football-specific outcomes in non-NFL athletes remain limited. Purpose: To report the return-to-sport (RTS) rates and functional outcomes at a minimum 2-year follow-up for active American football players competing at multiple levels after primary hip arthroscopy for FAI. Study Design: Case series; Level of evidence, 4. Methods: An institutional database was queried to identify all active American football players who underwent primary hip arthroscopy with labral repair between 2010 and 2023. Demographic characteristics, radiographic parameters, procedure details, complications, and reoperations were collected. Follow-up was completed at a minimum of 2 years to obtain updated patient-reported outcome measures (PROMs) as well as football-specific data, including current participation and RTS status. PROMs were reported as mean ± standard deviation, and categorical variables, including RTS, were reported as frequencies. Pre- versus postoperative PROMs were compared using t tests or Mann-Whitney U tests to assess outcomes. Results: In total, 49 hips in 38 male football players (age, 18.1 years; range, 14-26 years) were included. Most athletes played at the high school (74%) or college level (21%). A total of 51% played as linemen. Labral repair was performed in all cases. At a mean 7.6 years, mean modified Harris Hip Score was 90 ± 13, Hip Outcome Score–Activities of Daily Living was 95 ± 7, and Hip Outcome Score–Sport was 89 ± 17. Overall mean surgery satisfaction was 8.7 ± 1.7 (out of 10). Significant postoperative improvements were observed in all PROMs ( P ≤ .002). Twelve players (32%) did not attempt RTS due to other nonmedical factors and were excluded from return to sport analysis. A total of 23 (88%) players achieved RTS, and 3 players (12%) did not. Two players (8%) cited other injuries, and 1 player (4%) continued to have hip limitations. Four hips (8%) underwent reoperation at a mean 4.9 years postoperative. Conclusion: Amateur American football players undergoing primary hip arthroscopy for FAI demonstrated excellent patient-reported outcomes and a high RTS rate of 88%, when excluding those who did not return for nonmedical reasons, at a mean 7.6-year follow-up. Notable positional differences were observed across multiple levels of play. Although outcomes were generally favorable, both medical and nonmedical factors could limit return to sport, particularly among high school and college athletes.

Background: Injury to the medial ulnar collateral ligament (MUCL) is a common setback for throwing athletes, often requiring reconstruction with 12 to 18 months of rehabilitation. The authors previously described a more anatomic technique with improved mechanical strength as compared with the docking technique, which may allow for an accelerated return to sport. Purpose: To evaluate return-to-sport rates, time to return to sport, and the effect on the functional performance of amateur and professional throwing athletes who underwent anatomic MUCL reconstruction with suture tape augmentation. Study Design: Case series; Level of evidence, 4. Methods: A retrospective case series was performed including baseball players who underwent anatomic MUCL reconstruction with suture tape augmentation by a single surgeon from 2018 to 2022. Inclusion criteria consisted of a minimum 2-year follow-up, participation in baseball, and utilization of autograft (palmaris longus or gracilis). Patients who underwent previous MUCL reconstruction were excluded from the study. All patients initially followed an accelerated rehabilitation protocol. Outcome measures were collected, including Kerlan-Jobe Orthopaedic Clinic (KJOC), Single Assessment Numeric Evaluation (SANE), and Conway-Jobe scores, as well as throwing metrics such as ball velocity and spin rate. Results: Thirty-four baseball players (mean ± SD age, 21 ± 3 years) underwent primary MUCL reconstruction. Time of final follow-up was 36.1 ± 10.3 months. Of these, 16 were professional athletes and 18 were amateur. All throwers returned to live gameplay at a mean 10.1 ± 2.0 months after reconstruction (professional, 10.6 ± 2.3; amateur, 9.7 ± 1.8). Furthermore, 97% (94% professional, 100% amateur) advanced through the accelerated postoperative protocol without issues, and 91% (88% professional, 94% amateur) returned to the same role and 85% (75% professional, 94% amateur) to the same level of play. Professional postinjury KJOC scores improved from 42.6 ± 16 to 87.5 ± 8.3 and SANE scores from 25.0 ± 11.2 to 95.6 ± 4.2. Amateur postinjury KJOC scores improved from 35.6 ± 10.7 to 90.9 ± 8.6 and SANE scores from 57.5 ± 16.9 to 95.2 ± 7.2. No significant difference was identified in preinjury versus postreconstruction throwing velocity, ball spin rate, or horizontal/vertical ball movement. The overall failure rate was 2.9%, with 1 professional pitcher requiring revision for graft rupture at 3 years postoperatively. Conclusion: Anatomic reconstruction of the MUCL with suture tape is a viable option for MUCL injuries, allowing an expedited return to sport at 10.1 ± 2.0 months (professional, 10.6 ± 2.3; amateur, 9.7 ± 1.8) in baseball players, with a low failure rate.