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Background: Anterior cruciate ligament (ACL) tears are common knee injuries. Despite undergoing extensive rehabilitation after ACL reconstruction (ACLR), many patients have persistent quadriceps muscle weakness that limits their successful return to play and are also at an increased risk of developing knee osteoarthritis (OA). Human growth hormone (HGH) has been shown to prevent muscle atrophy and weakness in various models of disuse and disease but has not been evaluated in patients undergoing ACLR. Hypothesis: Compared with placebo treatment, a 6-week perioperative treatment course of HGH would protect against muscle atrophy and weakness in patients undergoing ACLR. Study Design: Randomized controlled trial; Level of evidence, 2. Methods: A total of 19 male patients (aged 18-35 years) scheduled to undergo ACLR were randomly assigned to the placebo (n = 9) or HGH (n = 10) group. Patients began placebo or HGH treatment twice daily 1 week before surgery and continued through 5 weeks after surgery. Knee muscle strength and volume, patient-reported outcome scores, and circulating biomarkers were measured at several time points through 6 months after surgery. Mixed-effects models were used to evaluate differences between treatment groups and time points, and as this was a pilot study, significance was set at P < .10. The Cohen d was calculated to determine the effect size. Results: HGH was well-tolerated, and no differences in adverse events between the groups were observed. The HGH group had a 2.1-fold increase in circulating insulin-like growth factor 1 over the course of the treatment period ( P < .05; d = 2.93). The primary outcome measure was knee extension strength, and HGH treatment increased normalized peak isokinetic knee extension torque by 29% compared with the placebo group ( P = .05; d = 0.80). Matrix metalloproteinase–3 (MMP3), which was used as an indirect biomarker of cartilage degradation, was 36% lower in the HGH group ( P = .05; d = –1.34). HGH did not appear to be associated with changes in muscle volume or patient-reported outcome scores. Conclusion: HGH improved quadriceps strength and reduced MMP3 levels in patients undergoing ACLR. On the basis of this pilot study, further trials to more comprehensively evaluate the ability of HGH to improve muscle function and potentially protect against OA in patients undergoing ACLR are warranted. Registration: NCT02420353 ( ClinicalTrials.gov identifier)

Introduction Patients with anterior cruciate ligament (ACL) tears have persistent quadriceps strength deficits that are thought to be due to altered neurophysiological function. Our goal was to determine the changes in muscle fiber contractility independent of the ability of motor neurons to activate fibers. Methods We obtained quadriceps biopsies of patients undergoing ACL reconstruction, and additional biopsies 1, 2, and 6 months after surgery. Muscles fiber contractility was assessed in vitro, along with whole muscle strength testing. Results Compared with controls, patients had a 30% reduction in normalized muscle fiber force at the time of surgery. One month later, the force deficit was 41%, and at 6 months the deficit was 23%. Whole muscle strength testing demonstrated similar trends. Discussion While neurophysiological dysfunction contributes to whole muscle weakness, there is also a reduction in the force generating capacity of individual muscle cells independent of alpha motor neuron activation. Muscle Nerve, 2018.

Background: Focal cartilage defects of the knee are a substantial cause of pain and disability in active patients. There has been an emergence of randomized controlled trials evaluating surgical techniques to manage such injuries, including marrow stimulation (MS), autologous chondrocyte implantation (ACI), and osteochondral autograft transfer (OAT). Purpose: A meta-analysis was conducted to determine if any single technique provides superior clinical results at intermediate follow-up. Study Design: Systematic review and meta-analysis of randomized controlled trials. Methods: The MEDLINE, EMBASE, and Cochrane Library databases were systematically searched and supplemented with manual searches of PubMed and reference lists. Eligible studies consisted exclusively of randomized controlled trials comparing MS, ACI, or OAT techniques in patients with focal cartilage defects of the knee. The primary outcome of interest was function (Lysholm score, International Knee Documentation Committee score, Knee Osteoarthritis Outcome Score) and pain at 24 months postoperatively. A meta-analysis using standardized mean differences was performed to provide a pooled estimate of effect comparing treatments. Results: A total of 12 eligible randomized trials with a cumulative sample size of 765 patients (62% males) and a mean (±SD) lesion size of 3.9 ± 1.3 cm2 were included in this review. There were 5 trials comparing ACI with MS, 3 comparing ACI with OAT, and 3 evaluating different generations of ACI. In a pooled analysis comparing ACI with MS, there was no difference in outcomes at 24-month follow-up for function (standardized mean difference, 0.47 [95% CI, –0.19 to 1.13]; P = .16) or pain (standardized mean difference, –0.13 [95% CI, –0.39 to 0.13]; P = .33). The comparisons of ACI to OAT or between different generations of ACI were not amenable to pooled analysis. Overall, 5 of the 6 trials concluded that there was no significant difference in functional outcomes between ACI and OAT or between generations of ACI. Conclusion: There is no significant difference between MS, ACI, and OAT in improving function and pain at intermediate-term follow-up. Further randomized trials with long-term outcomes are warranted.

Background: In the diagnosis and surgical treatment of cam-type femoroacetabular impingement (FAI), 3-dimensional (3D) imaging is the gold standard for detecting femoral head-neck junction malformations preoperatively. Intraoperative fluoroscopy is used by many surgeons to evaluate and verify adequate correction of the deformity. Purpose: (1) To compare radial reformatted computed tomography (CT) scans with 6 defined intraoperative fluoroscopic views before surgical correction to determine whether fluoroscopy could adequately depict cam deformity, and (2) to define the influence of femoral version on the clock-face location of the maximum cam deformity on these views. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: A consecutive series of 50 hips (48 patients) that underwent arthroscopic treatment for symptomatic FAI by a single surgeon were analyzed. Each patient underwent a CT scan and 6 consistent intraoperative fluoroscopy views: 3 views in hip extension and 3 views in hip flexion of 50°. The alpha angles of each of the fluoroscopic images were compared with the radial reformatted CT using a 3D software program. Femoral version was also defined on CT studies. Statistical analysis was performed using the Student t test, with P < .05 defined as significant. Results: Fifty-two percent of patients were male, average age 28 years (range, 15-56 years). The maximum mean alpha angle on fluoroscopy was 65° (range, 37°-93°) and was located on the anteroposterior (AP) 30° external rotation (ER) fluoroscopy view. In comparison, the mean CT-derived maximum alpha angle was 67° and was located at 1:15 ( P = .57). The mean clock-face positions of each of the fluoroscopy views (standardized to the right hip) were AP 30° internal rotation, 11:45; AP 0° (neutral) rotation, 12:30; AP 30° ER, 1:00; flexion/0° (neutral) rotation, 1:45; flexion/40° ER, 2:15; and flexion/60° ER, 2:45. Increased femoral anteversion (>20°) was associated with a significant change in the location of the maximum alpha angle (1:45 vs 1:15; P = .002). Conclusion: The described 6 fluoroscopic views are very helpful in localization and visualization of the typical cam deformity from 11:45 to 2:45 and can be used to reliably confirm a complete intraoperative resection of cam-type deformity in most patients. These views correlate with preoperative 3D imaging and may be of even greater importance in the absence of preoperative 3D imaging.

Background:Tendons are viscoelastic tissues that deform (elongate) in response to cyclic loading. However, the ability of a tendon to recover this elongation is unknown.Hypothesis:Tendon length significantly increases after in vivo or in vitro cyclic loading, and the ability to return to its original length through a cell-mediated contraction mechanism is an age-dependent phenomenon.Study Design:Controlled laboratory study.Methods:In vitro, rat tail tendon fascicles (RTTfs) from Sprague-Dawley rats of 3 age groups (1, 3, and 12 months) underwent 2% cyclic strain at 0.17 Hz for 2 hours, and the percentages of elongation were determined. After loading, the RTTfs were suspended for 3 days under tissue culture conditions and photographed daily to determine the amount of length contraction. In vivo, healthy male participants (n = 29; age, 19-49 years) had lateral, single-legged weightbearing radiographs taken of the knee at 60° of flexion immediately before, immediately after, and 24 hours after completing eccentric quadriceps loading exercises on the dominant leg to fatigue. Measurements of patellar tendon length were taken from the radiographs, and the percentages of tendon elongation and subsequent contraction were calculated.Results:In vitro, cyclic loading increased the length of all RTTfs, with specimens from younger (1 and 3 months) rats demonstrating significantly greater elongation than those from older (12 months) rats ( P = .009). The RTTfs contracted to their original length significantly faster ( P < .001) and in an age-dependent fashion, with younger animals contracting faster. In vivo, repetitive eccentric loading exercises significantly increased patellar tendon length ( P < .001). Patellar tendon length decreased 24 hours after exercises ( P < .001) but did not recover completely ( P < .001). There was a weak but significant ( R2= 0.203, P = .014) linear correlation between the amount of tendon contraction and age, with younger participants (30 years).Conclusion:Cyclic tendon loading results in a significant increase in tendon elongation under both in vitro and in vivo conditions. Tendons in both conditions demonstrated an incomplete return to their original length after 24 hours, and the extent of this return was age dependent.Clinical Relevance:The age- and time-dependent contraction of tendons, elongated after repetitive loading, could result in transient alterations in the mechanobiological environment of tendon cells. This, in turn, could induce the onset of catabolic changes associated with the pathogenesis of tendinopathy. These results suggest the importance of allowing time for contraction between bouts of repetitive exercise and may explain why age is a predisposing factor in tendinopathy.

Purpose The primary purpose was to compare ipsilateral hip internal rotation (IR) in male and female athletes with or without an anterior cruciate ligament (ACL) tear. A secondary purpose was to compare radiographic markers of femoroacetabular impingement (FAI) in patients with or without an ACL tear. Methods In this prospective case-control study, based on a power analysis, a convenience sample of 25 ACL-injured and 25 control patients matched by age and gender were examined over 14 months. The ACL injury group included preoperative patients 12-40 years old with an ACL rupture within the previous 3 months with no prior lower extremity injuries, ligamentous laxity, or arthralgias. Controls included patients presenting with an upper extremity complaint with no history of knee injury. In the outpatient clinic, hip axial rotation range of motion was measured with a goniometer on physical examination and hip radiographs were evaluated for morphologic variations consistent with FAI. Univariate analysis of variance was used to examine differences between groups. Results Each group had 13 males and 12 females, average ages of 22.8 ± 7.2 years (ACL group) versus 24.5 ± 7.9 years (controls; P = .439). The average sum of hip rotation (internal plus external) in patients with an ACL tear was 60.3 ± 12.4° compared with 72.6 ± 17.2° in controls ( P = .006). ACL-injured patients had decreased hip IR compared with controls, with respective mean measurements of 23.4 ± 7.6° versus 30.4 ± 10.4° ( P = .009). For every 10° increase in hip IR, the odds of having an ACL tear decreased by a factor of 0.419 ( P = .015). Conclusions Risk of ACL injury is associated with restricted hip IR, and as hip IR increases, the odds of having an ACL tear decreases. In addition, ACL injury is associated with FAI in a generalized population of male and female athletes, although causality cannot be determined and most ACL-injured patients do not exhibit hip complaints. Level of Evidence Level II, prognostic, prospective cohort study.

Background A persistent atrophy of muscle fibers and an accumulation of fat, collectively referred to as fatty degeneration, commonly occur in patients with chronic rotator cuff tears. The etiology of fatty degeneration and function of the residual rotator cuff musculature have not been well characterized in humans. We hypothesized that muscles from patients with chronic rotator cuff tears have reduced muscle fiber force production, disordered myofibrils, and an accumulation of fat vacuoles. Methods The contractility of muscle fibers from biopsy specimens of supraspinatus muscles of 13 patients with chronic full-thickness posterosuperior rotator cuff tears was measured and compared with data from healthy vastus lateralis muscle fibers. Correlations between muscle fiber contractility, American Shoulder and Elbow Surgeons (ASES) scores, and tear size were analyzed. Histology and electron microscopy were also performed. Results Torn supraspinatus muscles had a 30% reduction in maximum isometric force production and a 29% reduction in normalized force compared with controls. Normalized supraspinatus fiber force positively correlated with ASES score and negatively correlated with tear size. Disordered sarcomeres were noted, along with an accumulation of lipid-laden macrophages in the extracellular matrix surrounding supraspinatus muscle fibers. Conclusions Patients with chronic supraspinatus tears have significant reductions in muscle fiber force production. Force production also correlates with ASES scores and tear size. The structural and functional muscle dysfunction of the residual muscle fibers is independent of the additional area taken up by fibrotic tissue. This work may help establish future therapies to restore muscle function after the repair of chronically torn rotator cuff muscles.

This study aimed to characterize the radiographic deformity observed in a consecutive series of butterfly goalies with symptomatic mechanical hip pain and to use computer-based software analysis to identify the location of impingement and terminal range of motion. We also compared these analyses to a matched group of positional hockey players with symptomatic femoroacetabular impingement (FAI).A consecutive series of 68 hips in 44 butterfly-style hockey goalies and a matched group of 34 hips in 26 positional hockey players who underwent arthroscopic correction for symptomatic FAI were retrospectively analyzed. Each patient underwent preoperative anteroposterior (AP) and modified Dunn lateral radiographs and computed tomography (CT) of the affected hips. Common FAI measurements were assessed on plain radiographs. Patient-specific, CT-based 3-dimensional (3D) models of the hip joint were developed, and the femoral version, alpha angles at each radial clock face position, and femoral head coverage were calculated. Maximum hip flexion, abduction, internal rotation in 90° flexion (IRF), flexion/adduction/internal rotation (FADIR), and butterfly position were determined, and the areas of bony collision were defined.Butterfly goalies had an elevated mean alpha angle on both AP (61.3°) and lateral radiographs (63.4°) and a diminished beta angle (26.0°). The mean lateral center-edge angle (LCEA) measured 27.3° and acetabular inclination was 6.1°. A crossover sign was present in 59% of the hips. The maximum alpha angle on the radial reformatted computed tomographic scan was significantly higher among the butterfly goalies (80.9° v 68.6°; P.0001) and was located in a more lateral position (1:00 o'clock v. 1:45 o'clock; P.0001) compared with positional players.Symptomatic butterfly hockey goalies have a high prevalence of FAI, characterized by a unique femoral cam-type deformity and noted by an elevated alpha angle and loss of offset, which is greater in magnitude and more lateral when compared with that in positional hockey players. Associated acetabular dysplasia is also common among hockey goalies.Level IV, prognostic case series.

Objectives: A common pathophysiological change that occurs in torn rotator cuff muscles is atrophy of muscle fibers and an accumulation of intramuscular fat, collectively referred to as "fatty degeneration." For many patients with chronic rotator cuff tears that undergo surgical repair, fatty degeneration is not resolved. The etiology of fatty degeneration has not been characterized in humans, and gaining greater insight into the mechanisms that lead to the development of atrophy and fat accumulation will likely improve the recovery of patients who undergo surgical repair of a torn rotator cuff. The purpose of this study was to gain a greater understanding of the changes in muscle fiber contractility, myofibril architecture and fat accumulation in patients with rotator cuff tears. We hypothesized that torn rotator cuff muscles have reduced muscle fiber force production, disordered myofibrils and an accumulation of fat vacuoles and lysosomes. Methods: This study was approved by our institution's IRB. Prior to enrollment in the study, informed consent was obtained from patients with a full thickness supraspinatus tear as verified by MRI or ultrasound by a fellowship-trained musculoskeletal radiologist. Biopsies of the supraspinatus and anterior deltoid were obtained at the time of repair and prepared for muscle contractility testing or microscopy. The contractility of permeabilized muscle fibers was performed as previously described, and force values of torn supraspinatus and intact deltoid muscles were compared to age-matched force values of healthy fibers sampled from the vastus lateralis muscle in a previous study. Scanning electron micrographs and immunohistochemistry were also performed on select muscle biopsies. Results: Compared with healthy muscle fibers from the vastus lateralis, there was a 29% reduction in specific force (maximum isometric force normalized to fiber cross-sectional area) in torn supraspinatus muscles, and a 34% reduction in specific force for deltoid muscle fibers (Figure 1A, PConclusion: Combined, these results identify chronic structural and mechanical changes in torn rotator cuff muscles that may explain the poor functional capacity of the muscles after repair. While the supraspinatus muscle had reduced force production, a reduction in force was also noted in the deltoid which may parallel symptomatic rotator cuff disease. Further, the accumulation of fat in large lipid vacuoles and high lysosome densities near myofibrils suggest that a portion of the intramyocellular fat that accumulates in torn cuff muscles likely comes as a result of myofibril degradation. We have also identified for the first time that a portion of the extramyocellular fat in torn rotator cuff muscles accumulates in fatty macrophages/foam cells. Future therapies that target lysosomal-mediated myofibril degradation or macrophage accumulation may help to ameliorate the severity of fatty degeneration in patients with rotator cuff tears.

Femoroacetabular impingement (FAI) is one of the most common causes of early cartilage and labral damage in the nondysplastic hip. Biomarkers of cartilage degradation and inflammation are associated with osteoarthritis. It was not known whether patients with FAI have elevated levels of biomarkers of cartilage degradation and inflammation.Compared with athletes without FAI, athletes with FAI would have elevated levels of the inflammatory C-reactive protein (CRP) and cartilage oligomeric matrix protein (COMP), a cartilage degradation marker.Controlled laboratory study.Male athletes with radiographically confirmed FAI (n = 10) were compared with male athletes with radiographically normal hips with no evidence of FAI or hip dysplasia (n = 19). Plasma levels of COMP and CRP were measured, and subjects also completed the Short Form-12 (SF-12) and Hip Disability and Osteoarthritis Outcome Score (HOOS) surveys.Compared with controls, athletes with FAI had a 24% increase in COMP levels and a 276% increase in CRP levels as well as a 22% decrease in SF-12 physical component scores and decreases in all of the HOOS subscale scores.Athletes with FAI demonstrate early biochemical signs of increased cartilage turnover and systemic inflammation.Chondral injury secondary to the repetitive microtrauma of FAI might be reliably detected with biomarkers. In the future, these biomarkers might be used as screening tools to identify at-risk patients and assess the efficacy of therapeutic interventions such as hip preservation surgery in altering the natural history and progression to osteoarthritis.

Background: After anterior cruciate ligament (ACL) reconstruction, there is significant atrophy of the quadriceps muscles that can limit full recovery and place athletes at risk for recurrent injuries with return to play. The cause of this muscle atrophy is not fully understood. Hypothesis: Circulating levels of proatrophy, proinflammatory, and cartilage turnover cytokines and biomarkers would increase after ACL reconstruction. Study Design: Descriptive laboratory study. Methods: Patients (N = 18; mean age, 28 ± 2.4 years) underwent surgical reconstruction of the ACL after a noncontact athletic injury. Circulating levels of biomarkers were measured along with Short Form−12, International Knee Documentation Committee, and objective knee strength measures preoperatively and at 6 postoperative visits. Differences were tested using repeated-measures 1-way analysis of variance. Results: Myostatin, TGF-β, and C-reactive protein levels were significantly increased in the early postoperative period and returned to baseline. Cartilage oligomeric matrix protein levels decreased immediately after surgery and then returned to baseline. CCL2, CCL3, CCL4, CCL5, EGF, FGF-2, IGF-1, IL-10, IL-1α, IL-1β, IL-1ra, IL-6, myoglobin, and TNF-α were not different over the course of the study. Conclusion: An increase in potent atrophy-inducing cytokines and corresponding changes in knee strength and functional scores were observed after ACL reconstruction. Clinical Relevance: Although further studies are necessary, the therapeutic inhibition of myostatin may help prevent the muscle atrophy that occurs after ACL reconstruction and provide an accelerated return of patients to sport.

Ross JR, Bedi A, Stone RM, Sibilsky Enselman E, Leunig M, Kelly BT, Larson CM. Intraoperative fluoroscopic imaging to treat cam deformities: correlation with 3-dimensional computed tomography. Am J Sports Med. 2014;42(6):1370-1376. (Original DOI: 10.1177/0363546514529515 )

IN THE past decade, obstructive emphysema occurring in infants and children has gained recognition as a definite clinical entity and at times a surgical emergency. Although this condition had been described before, the first successful lobectomy for obstructive emphysema in infancy was performed by Fischer, Tropea, and Bailey, in 1943. 1 Since that time, there have been occasional case reports. These authors were able to find an additional 14 cases reported in the literature. Whitesell and White 3 reported another case in 1952. Sloan 4 reported his findings on four cases in 1953. In the discussion that followed his paper, an additional 16 cases were reported. Our case makes a total of 41 cases reported in the literature. Because this condition is of interest to both the pediatrician and the surgeon, the following case is reported. It demonstrates how well infants tolerate major thoracic surgery. It is of interest to