Outcomes of Primary Anterior Cruciate Ligament (ACL) Repair for Proximal Tears: A Systematic Review and Meta-Analysis.

The purpose of this study is to compare failure rates among different techniques of primary anterior cruciate ligament (ACL) repair for the treatment of proximal ACL ruptures. Meta-analysis and systematic review were completed, and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. Studies from Embase, Cochrane, and PubMed published between June 2011 and June 2022 reporting outcomes of primary ACL repair on proximal tears with a minimum two-year follow-up were included. Primary ACL repair was divided into dynamic, static, and non-augmented repair. The primary outcome was failure rates, and the secondary outcomes included patient-reported outcomes (PROs) and anterior tibial stability (ATT). Eighteen studies on primary ACL repair were included, with a total of 614 patients (ages ranging from 6 to 65, 60% male). Only two studies were level 1 randomized controlled clinical trials. The static repair had a failure rate of 33 out of 261 (12.6%), non-augmented was 17 out of 179 (9.4%), and dynamic repair was 31 out of 174 (17.8%); no statistically significant difference was found comparing the failure rates (p = 0.090). PROs using the International Knee Documentation Committee (IKDC) and Lysholm scores had weighted averages of 91.7 (95% confidence interval (CI): 89.6-93.8) and 94.7 (95% CI: 92.7-96.7), respectively. ATT had a weighted average of 1.668 mm (95% CI: 1.002-2.334). The primary findings of this paper include a 12.6% combined failure rate for primary proximal ACL repair with no significant difference in failure rate or PROs when accounting for the methodology of repair at a minimum two-year follow-up. It is important to note the lack of high-quality randomized controlled trials, the heterogeneity of included studies, and the lack of long-term data. Despite these limitations, the findings of the current analysis suggest that primary repair may be a useful treatment option for indicated candidates with proximal ACL ruptures. Further long-term and higher-quality comparative studies on ACL reconstruction are warranted.

Chronic exertional compartment syndrome is frequently diagnosed through static compartment pressure measurements and managed with fasciotomy: A systematic review.

OBJECTIVES: Chronic exertional compartment syndrome (CECS) can be diagnosed either clinically or with intra-compartmental pressure monitor measurements and can be treated surgically or conservatively. METHODS: A systematic review was performed on diagnostic and treatment modalities for CECS. Included studies were those that reported both their specific diagnostic modality and treatment regimens. Both surgical and conservative treatment strategies were considered. Demographic variables, diagnostic modalities, patient satisfaction and return to sport, the number of surgical incisions used for the anterior compartment fasciotomy, and the specific conservative treatment regimens were also recorded. Diagnostic modalities were grouped into one of three groups: 1) static compartment pressure monitor, 2) dynamic pressure monitoring, and 3) strictly clinical diagnosis. RESULTS: The literature search identified 373 studies, of which 29 were included for final analysis. In total, there were 1270 total patients. Twenty-four studies used static compartment pressure monitors, 5 studies used dynamic pressure monitors and 2 studies used a strictly clinical diagnosis. Surgical management with fasciotomy was performed in 25 studies with a total of 1018 patients, while conservative management was used in 252 patients in 9 studies (5 studies included surgical and conservative treatments). Among surgical studies, 15 used a single-incision technique for anterior compartment fasciotomy, while 6 used a 2-incision technique. The reported satisfaction after fasciotomy was 42-94% while the return to sport was 26-100%. The reported return to sport in conservative management studies was 25-35%. CONCLUSION: This systematic review found that the majority of clinical reports utilize static compartment pressure measurements to diagnose CECS, with fewer studies using dynamic intra-compartment pressure monitors. Additionally, surgical fasciotomy using a single-incision technique was the most common treatment strategy for anterior compartment CECC, with some studies reporting success with the two-incision technique. STUDY DESIGN: Systematic review, level 4.

Implementing the Lever Sign in the Emergency Department: Does it Assist in Acute Anterior Cruciate Ligament Rupture Diagnosis? A Pilot Study.

BACKGROUND: Within the emergency department (ED) setting, anterior cruciate ligament (ACL) rupture is commonly misdiagnosed, leading to improper treatment and potential meniscal injury and total joint replacement. Utilizing traditional clinical tests to diagnosis ACL rupture leads to the correct diagnosis in about 30% of cases. The lever sign is a new and effective clinical test used to diagnose ACL rupture with 100% sensitivity. OBJECTIVE: We aim to study if the lever sign used in the ED setting is more sensitive to diagnose ACL rupture than traditional tests. METHODS: Patients between 12 and 55 years of age were examined utilizing either traditional methods or the lever sign. Diagnostic findings in the ED were compared with those of a sports medicine specialist using magnetic resonance imaging as the diagnostic standard. A survey was given to ED providers to collect data on diagnosis and physician confidence in diagnosis. RESULTS: The sensitivity of the lever sign was 100% (94.7% accuracy, 93.75% specificity), whereas the sensitivity of the anterior drawer/Lachman test was 40% (87.5% accuracy, 100% specificity). Physician confidence in diagnosis was higher utilizing the lever sign vs. the anterior drawer/Lachman test at 8.45 (±1.82) compared with 7.72 (±1.82) out of 10, respectively. There was no statistically significant association between diagnostic accuracy with either test and level of training of the ED provider. CONCLUSION: Implementation of the lever sign in the ED setting resulted in a higher sensitivity, higher physician confidence in screening test diagnosis, and a decrease in the number of undiagnosed ACL ruptures.

A Biomechanical and Structural Comparison of Articular Cartilage and Subchondral Bone of the Glenoid and Humeral Head.

BACKGROUND: The underlying cause of glenohumeral arthritis is poorly understood. Glenohumeral arthrosis patterns have been classified and described, and differential contact stresses within the joint have been implicated as a cause of joint degeneration, but the intrinsic cause of degeneration patterns in the glenohumeral joint (GHJ) remains largely unknown. PURPOSE/HYPOTHESIS: The purpose of this study was to assess morphological and mechanical differences in articular cartilage (AC) and subchondral bone (SCB) of the glenoid and humeral head in matched cadaveric specimens. We hypothesized that there would be significant zone-dependent differences between the intrinsic characteristics (AC thickness, SCB thickness, compressive forces) of the glenoid and humeral head. STUDY DESIGN: Descriptive laboratory study. METHODS: Ten human cadaveric GHJs (mean age, 60.2 years) were dissected to expose articular surfaces to facilitate biomechanical testing. A 2-mm and 6-mm osteochondral plug was harvested at 5 zones (central, anterior, posterior, inferior, superior) on the glenoid and humeral head (N = 200 plugs). Each 2-mm core was histologically sectioned and stained with hematoxylin and eosin. AC thickness measurements were taken using light microscopy. The 6-mm plugs were imaged using micro-computed tomography to measure SCB thickness. After imaging, AC specimens were removed from the SCB and tested in confined compression. The compressive aggregate modulus (HA0), compressive stiffening coefficient (ß), and compressive modulus at 16% strain (HA0.16) and at 50% strain (HA0.50) were calculated. RESULTS: The overall AC thickness was significantly greater on the glenoid. The glenoid also had significantly thicker AC at the inferior, posterior, and superior zones as well as significantly higher SCB thickness overall and significantly greater SCB thickness at the anterior and central zones. The glenoid had significantly greater overall HA0.50 and HA0.50 values at the superior zone and had a significantly greater overall compressive stiffening coefficient (ß). CONCLUSION: The glenoid had thicker AC, thicker SCB, and greater compressive stiffness at high strain. CLINICAL RELEVANCE: These intrinsic differences may help better elucidate the cause of differential degeneration patterns between the glenoid and humeral head.

Bilateral Superior Labrum Anterior to Posterior (SLAP) Tears With Abnormal Anatomy of Biceps Tendon.

There have been several descriptions of variant anatomy of the long head of the biceps tendon (LHBT). A recent literature review identified 8 cases of anomalous intracapsular attachment of the LHBT. In this report, we discuss a distinctive case of a young athlete who presented with symptoms consistent with bilateral superior labrum anterior to posterior (SLAP) tears that were unresponsive to conservative measures. Magnetic resonance imaging and arthroscopic findings of this patient confirmed that the patient had type II SLAP tears, a Buford complex anteriorly, and perhaps most important, confluence of the biceps tendon itself to the undersurface of the capsule within the rotator interval. Our case proposes that anomalous insertion of the LHBT, as well as other labral and biceps anchor variations, are not always a benign finding at the time of arthroscopy. In this particular case, the tethering of the biceps tendon to the capsule is thought to have increased stress on the superior labrum and contributed to the development of the bilateral symptomatic type II SLAP tears that were identified and treated in this young athlete.

A review of the anterolateral ligament of the knee: current knowledge regarding its incidence, anatomy, biomechanics, and surgical dissection.

PURPOSE: To systematically review current literature on the anterolateral ligament (ALL) of the knee. METHODS: We searched the PubMed/Medline database for publications specifically addressing the ALL. We excluded studies not written in English, studies not using human cadavers or subjects, and studies not specifically addressing the ALL. Data extraction related to the incidence, anatomy, morphometry, biomechanics, and histology of the ALL and its relation to the Segond fracture was performed. RESULTS: The incidence of the ALL ranged from 83% to 100%, and this range occurs because of small discrepancies in the definition of the ALL's bony insertions. The ALL originates anterior and distal to the femoral attachment of the lateral collateral ligament. It spans the joint in an oblique fashion and inserts between the fibular head and Gerdy tubercle on the tibia. Exact anatomic and morphometric descriptions vary in the literature, and there are discrepancies regarding the ALL's attachment to the capsule and lateral meniscus. The ALL is a contributor to tibial internal rotation stability, and histologically, it exhibits parallel, crimped fibers consistent with a ligamentous microstructure. The footprint of the ALL has been shown to be at the exact location of the Segond fracture. CONCLUSIONS: The ALL is a distinct ligamentous structure at the anterolateral aspect of the knee, and it is likely involved in tibial internal rotation stability and the Segond fracture. LEVEL OF EVIDENCE: Level IV, systematic review of anatomic and imaging studies.

Risk-Prone Pitching Activities and Injuries in Youth Baseball: Findings From a National Sample.

BACKGROUND: There are relatively few published epidemiological studies that have correlated pitching-related risk factors with increased pitching-related arm problems as well as injuries. HYPOTHESIS: High pitching volume and limited recovery will lead to arm fatigue, thus placing young pitchers at a greater risk for elbow and shoulder problems and, subsequently, an increased risk for arm injuries. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A national survey was conducted among 754 youth pitchers (ages 9 to 18 years) who had pitched in organized baseball leagues during the 12 months before the survey. Self-reported risk-prone pitching activities were identified and compared with recommendations by the American Sports Medicine Institute. Relationships between self-reported pitching activities, shoulder and elbow problems, and injuries were assessed using multivariable logistic regression. RESULTS: Of the 754 participating pitchers, 43.4% pitched on consecutive days, 30.7% pitched on multiple teams with overlapping seasons, and 19.0% pitched multiple games a day during the 12 months before the study. Pitchers who engaged in these activities had increased risk of pitching-related arm pain (odds ratio [OR] = 2.53, 95% confidence interval [CI] = 1.14-5.60; OR = 1.85, 95% CI = 1.02-3.38; OR = 1.89, 95% CI = 1.03-3.49, respectively). Nearly 70% of the sample reported throwing curveballs, which was associated with 1.66 (95% CI = 1.09-2.53) greater odds of experiencing arm pain while throwing. Pitching-related arm tiredness and arm pain were associated with increased risk of pitching-related injuries. Specifically, those who often pitched with arm tiredness and arm pain had 7.88 (95% CI = 3.88-15.99) and 7.50 (95% CI = 3.47-16.21) greater odds of pitching-related injury, respectively. However, pitching on a travel baseball club, playing baseball exclusively, or playing catcher were not associated with arm problems. CONCLUSION: The results of this study, along with those of others, reinforce the importance of avoiding risk-prone pitching activities to prevent pitching-related injuries among youth pitchers.

T1ρ magnetic resonance imaging for detection of early cartilage changes in knees of asymptomatic collegiate female impact and nonimpact athletes.

OBJECTIVE: To determine if T1ρ magnetic resonance imaging (T1ρ MRI) could assess early articular cartilage changes in knees of asymptomatic female collegiate athletes. It was hypothesized that impact cohort would demonstrate greater changes than nonimpact cohort. DESIGN: An institutional review board-approved prospective cohort study. Blinded MRI analyses. SETTING: Participants from collegiate athletic program. Imaging at university hospital, February 2008 to July 2009. PARTICIPANTS: Inclusion criteria were female collegiate athletes in athletic season and asymptomatic. Exclusion criteria were previous/current knee injuries/surgeries. Twenty-one female NCAA Division I athletes, 11 impact (basketball players) and 10 nonimpact (swimmers) participants were consented and imaged with 3.0-T MRI (Siemens) and T1ρ sequence (University of Pennsylvania). One patient was removed (injury diagnosis). Final roster was 10 impact and 10 nonimpact participants. No difference in cohort body mass index, height, or weight. MAIN OUTCOME MEASURES: Average T1ρ relaxation times (ART) for patellar and femoral cartilage to analyze defined regions and depth and modified International Cartilage Repair Society classification. RESULTS: Statistical analyses showed that ART of radial zone of central third weight-bearing region of cartilage in basketball players was significantly greater (P = 0.041) than swimmers and ART of the superficial zone in basketball players was significantly less (P = 0.003) than that of swimmers. For both groups, the ART of superficial zones were significantly greater than that of radial zones (P < 0.001). Four impact athletes showed macroscopic changes (none in nonimpact cohort). CONCLUSIONS: T1ρ MRI detected early changes in articular cartilage of asymptomatic collegiate female impact athletes, with significant differences between cohorts in radial zone of central third weight-bearing region and superficial zones ART. Both cohorts showed increased ART in superficial zone. Four impact athletes showed macroscopic changes. CLINICAL RELEVANCE: This study demonstrates a quantitative MRI sequence able to detect signal differences in articular cartilage in asymptomatic athletes.

The acute effect of bipolar radiofrequency energy thermal chondroplasty on intrinsic biomechanical properties and thickness of chondromalacic human articular cartilage.

Radio frequency energy (RFE) thermal chondroplasty has been a widely-utilized method of cartilage debridement in the past. Little is known regarding its effect on tissue mechanics. This study investigated the acute biomechanical effects of bipolar RFE treatment on human chondromalacic cartilage. Articular cartilage specimens were extracted (n = 50) from femoral condyle samples of patients undergoing total knee arthroplasty. Chondromalacia was graded with the Outerbridge classification system. Tissue thicknesses were measured using a needle punch test. Specimens underwent pretreatment load-relaxation testing using a spherical indenter. Bipolar RFE treatment was applied for 45 s and the indentation protocol was repeated. Structural properties were derived from the force-time data. Mechanical properties were derived using a fibril-reinforced biphasic cartilage model. Statistics were performed using repeated measures ANOVA. Cartilage thickness decreased after RFE treatment from a mean of 2.61 mm to 2.20 mm in Grade II, II-III, and III specimens (P < 0.001 each). Peak force increased after RFE treatment from a mean of 3.91 N to 4.91 N in Grade II and III specimens (P = 0.002 and P = 0.003, respectively). Equilibrium force increased after RFE treatment from a mean of 0.236 N to 0.457 N (P < 0.001 each grade). Time constant decreased after RFE treatment from a mean of 0.392 to 0.234 (P < 0.001 for each grade). Matrix modulus increased in all specimens following RFE treatment from a mean 259.12 kPa to 523.36 kPa (P < 0.001 each grade). Collagen fibril modulus decreased in Grade II and II-III specimens from 60.50 MPa to 42.04 MPa (P < 0.001 and P = 0.005, respectively). Tissue permeability decreased in Grade II and III specimens from 2.04 ∗10(-15) m(4)/Ns to 0.91 ∗10(-15) m(4)/Ns (P < 0.001 and P = 0.009, respectively). RFE treatment decreased thickness, time constant, fibril modulus, permeability, but increased peak force, equilibrium force, and matrix modulus. While resistance to shear and tension could be compromised due to removal of the superficial layer and decreased fibril modulus, RFE treatment increases matrix modulus and decreases tissue permeability which may restore the load- bearing capacity of the cartilage.

Biomechanical verification that PCL reconstruction is unnecessary in the muscle-stabilized knee.

Treatment of isolated posterior cruciate ligament (PCL) injuries is controversial. This is due in part to the discrepancy between clinical and biomechanical studies in the literature. Clinically, isolated PCL injuries are treated nonoperatively, and patients do well as long as they have adequate quadriceps function. Biomechanically, however, PCL injuries have been shown in cadavers to lead to altered kinematics and increased contact pressures. These studies, however, did not simulate weight-bearing muscle forces, which can compensate for the PCL deficiency. We sought to study the biomechanical effects of PCL deficiency and reconstruction in a cadaveric knee, but with reproduction of the muscle-stabilizing effects of the quadriceps and hamstring muscles. We used a novel 6 degrees of freedom testing system to simulate a muscle-stabilized cadaveric knee and recorded both kinematics and contact pressure data. Four conditions were tested: normal, PCL-deficient, and PCL single- and double-bundle reconstructed states. We found that with muscle stabilization, there were no significant changes in kinematics or contact pressures in the knee between any of these conditions. This corroborates clinical findings and verifies that PCL reconstruction is unnecessary in the muscle-stabilized knee.

Failure of coracoclavicular artificial graft reconstructions from repetitive rotation.

PURPOSE: To assess how suture type and suture construct in an augmented Weaver-Dunn reconstruction affect coracoclavicular sling failure and rotary stability. METHODS: Fifteen cadaveric shoulders were tested in rotation about the long axis of the clavicle with 10 lb of simulated arm weight. The clavicle was rotated 50 degrees about its long axis, and the applied torque was recorded. Next, modified Weaver-Dunn reconstruction was conducted. Two types of coracoclavicular sling (opposed drill holes through the clavicle and complete loop around the clavicle) were tested by use of 3 different sutures (FiberWire [Arthrex, Naples, FL], Mersilene tape [Ethicon, Somerville, NJ], and braided polydioxanone [PDS] [Ethicon]). For each sling-suture combination, the joint was retested over 50 degrees of rotation and then cycled over 40 degrees of rotation for 15,000 cycles or until failure. RESULTS: After modified Weaver-Dunn reconstruction with either sling construct, mean torque over 50 degrees of acromioclavicular rotation was significantly reduced in posterior (P < .0001) and anterior (P < .0001) rotation, with any suture material tested. When the coracoclavicular sling was placed through opposed drill holes, no wear to the bone or suture was observed. When the sling material was looped around the clavicle, FiberWire and PDS resulted in abrasion of soft tissue and periosteum. In all cases sawing motion between bone and suture was observed at the coracoid. The FiberWire itself failed at a mean of 8,213 cycles. Some wear was noted in the Mersilene tape. PDS suture showed no wear. CONCLUSIONS: In a cadaveric model of modified Weaver-Dunn reconstruction, a coracoclavicular suture loop was used to augment coracoacromial ligament transfer. Suture loops secured around the entire clavicle were shown to contribute to increased abrasive wear. Securing suture loops through opposed drill holes in the clavicle resulted in decreased abrasive wear. CLINICAL RELEVANCE: Proper selection of suture type and suture construct may affect the failure rate of augmented Weaver-Dunn reconstructions.

Effects of zone-specific superior labral detachment on biceps anchor stability.

PURPOSE: This study aimed to elucidate the degree of biceps anchor displacement that occurs when specific zones of the superior labrum are detached from the glenoid. STUDY DESIGN: Descriptive laboratory study. METHODS: Twelve cadaveric scapulae with intact labrums were prepared by removing the surrounding musculature with the labrum, biceps anchor, and biceps tendon carefully preserved. Pulleys were used to apply traction in 3 different directions- superior, lateral, and combined posterior/superior/lateral, to simulate the "peel-back" mechanism-while a continuous 1.13 kg of traction was applied to the biceps tendon. Labral tears were created by sharp incisions in isolation and in combinations of 3 zones defined relative to the glenoid fossa: anterior, posterior, or superior. The displacement of the biceps anchor (position of the marker after the simulated lesion relative to the marker position with the labrum intact) was measured relative to a rigid reference frame. RESULTS: The greatest degree of displacement occurred with the sectioning of all 3 zones, followed by the sectioning of 2 adjacent zones. Superior traction created the least displacement in all combinations, while lateral traction created maximal displacement, with one exception: in the setting of anterosuperior/superior lesions, maximal displacement was observed using the peel-back mechanism. CONCLUSION: Biceps anchor displacement, particularly the degree and direction of displacement, is affected by the labral detachment pattern. All 3 labral zones assessed in this study have important biomechanical contributions to biceps anchor displacement. CLINICAL SIGNIFICANCE: These findings have important implications relating to the clinician's arthroscopic assessment of superior labrum anterior and posterior (SLAP) tears, as well as the determination of need for stabilization. This information is particularly useful when treating SLAP tears in certain laborers and athletes, whose activities may cause specific biceps anchor displacement patterns.

The triad of varus malalignment, meniscectomy, and chondral damage: a biomechanical explanation for joint degeneration.

This biomechanical study evaluates the effect of varus malalalignment on knees with a chondral defect, both pre- and post-medial meniscectomy. Eight fresh-frozen cadaveric knees were first loaded physiologically. The knees were next loaded in increasing increments of varus. This loading cycle then was repeated after a chondral defect had been created, both pre- and post-medial meniscectomy. We found that a relatively small degree of varus malalignment caused a dramatic alteration in articular surface contact pressure and medial compartment loading, especially in the presence of chondral damage and/or medial meniscectomy. These findings may have important implications relating to the treatment of younger individuals with varus knees who have sustained meniscal and/or chondral damage.

Fifth metatarsal stress fractures in elite basketball players: evaluation of forces acting on the fifth metatarsal.

Our hypothesis in this study was that significant forces act on the fifth metatarsal during certain maneuvers commonly performed while playing basketball and that medial arch support influences these forces. Eleven male collegiate basketball players participated in this study. Electronic pressure sensors capable of dynamic readings were inserted into the players' shoes, and surface electromyographic (EMG) electrodes were placed over the peroneus longus and brevis muscles. The players performed 3 common maneuvers postulated to place maximal stress on the fifth metatarsal. The maneuvers were performed in a standard basketball shoe, then in a shoe with an orthosis supporting the arch. During each of these maneuvers, EMG activity of the ankle everters was recorded, along with maximal force, total work, and time elapsed beneath the fifth metatarsal.

Muscle transfers involving the shoulder.

Muscle transfer provides a viable treatment option for several difficult problems involving the shoulder. Muscle transfer is often the only alternative to a salvage procedure such as shoulder fusion, and whereas salvage procedures provide pain relief at the cost of function, muscle transfer can provide pain relief while retaining acceptable function. The five most commonly encountered shoulder problems for which muscle transfer can be utilized are subscapularis rupture, irreparable rotator cuff tear, deltoid injury and dysfunction, trapezial paralysis, and serratus anterior scapular winging. Although numerous muscle transfer procedures have been described, the following procedures have proven the most reliable and are the focus of this article: 1) transfer of the pectoralis major for subscapularis rupture, 2) transfer of the latissimus dorsi for irreparable rotator cuff tears, 3) latissimus dorsi transfer for deltoid injury or dysfunction, 4) modified Eden-Lange procedure for trapezial paralysis, and 5) modified Marmor-Bechtol pectoralis major transfer for serratus anterior scapular winging.

Dynamic evaluation of contact pressure and the effects of graft harvest with subsequent lateral release at osteochondral donor sites in the knee.

PURPOSE: To dynamically evaluate contact pressure about the periphery of the lateral femoral condyle in intact knees, to qualify the effects of osteochondral donor graft harvest on this contact pressure, and to quantify the effects of lateral release on contact pressure after graft harvest. TYPE OF STUDY: Cadaveric analysis. METHODS: Digital electronic pressure-sensing cells were used to measure contact pressure over the periphery of the lateral femoral condyle in 10 fresh-frozen knee specimens. Nonweightbearing resistive extension was simulated as the knees were placed through a functional range of motion. Dynamic pressure readings were evaluated over intact cartilage, around the rims of four 5-mm osteochondral defects, and after lateral release. RESULTS: The pressure cells were all subjected to contact pressures as the knees were placed through a functional range of motion. Average maximal contact pressure progressed distally as the knees were flexed. The creation of 5-mm osteochondral defects did not lead to a significant increase in rim stress concentration over the surrounding cartilage. Lateral release resulted in small decreases in contact pressure over the osteochondral defects. CONCLUSIONS: The creation of 5-mm donor defects about the lateral aspect of the lateral femoral condyle does not lead to significant alterations in local contact pressure. CLINICAL RELEVANCE: Our biomechanical findings may have important implications relating to cartilage restoration using osteochondral autografting procedures. Donor-site morbidity may be minimized if donor-site defects are limited to 5 mm and smaller.

Anterior cruciate ligament injuries in children with open physes: evolving strategies of treatment.

Injury to the anterior cruciate ligament is one of the most common sports-related injuries of the knee. Before the 1980s, the incidence of this injury in skeletally immature patients was thought to be rare. However, with the increasing participation of children in sports-related activities and an increased awareness and diagnostic capability of the medical community, midsubstance tears of the anterior cruciate ligament have become more common in patients with open physes. Significant controversy exists regarding management of anterior cruciate ligament injuries in children with open physes. Traditional management has been nonoperative, consisting of physical therapy, bracing, and activity modification. Surgical reconstruction has generally been postponed until the patient is nearing, or has reached, skeletal maturity. In contrast to this traditional treatment algorithm, the recent literature uniformly indicates that nonoperative management of anterior cruciate ligament tears in children results in less than optimal results. Compliance is certainly an issue, and even though patients may refrain from organized sports activities, they are still going to be "kids." Recurrent instability, pain, and an inability to return to the preinjury level of athletics often result. Even more worrisome are the risks of secondary meniscal tears and the possibility of early degenerative joint disease. Recently, there has been an increased interest in early, aggressive operative management to restore stability to the immature knee. Proponents of nonoperative treatment point to the risk of growth arrest associated with violation of the physis. Proponents of early operative stabilization advocate that restoration of stability provides for opportunity to return to full activity and provides good long-term outcomes, all with minimal risk to the physis. This article reviews both the basic science and clinical research on this controversial topic.

Hyperconcavity of the lumbar vertebral endplates in the elite football lineman.

BACKGROUND: Hyperconcavity of the vertebral endplates is a previously unreported radiologic phenomenon. PURPOSE: To analyze hyperconcavity of the vertebral endplates with expansion of the disk space in pre-National Football League lineman and to determine its clinical significance. STUDY DESIGN: Descriptive anatomical study. METHODS: Over a 2-year period (1992-1993), 266 elite football linemen were evaluated at the National Football League scouting combine held in Indianapolis, Indiana. Evaluation focused on the lumbosacral spine and included history, physical examination, and lateral radiographs. Measurements were taken of all the vertebral endplate defects of involved vertebrae and compared with an age-matched control group of 110 patients. RESULTS: The analyzed data revealed the following: (1) hyperconcavity of the vertebral endplates appeared as a distinct entity in a high percentage of pre-National Football League lineman (33%) compared with age-matched controls (8%), (2) there was a trend toward a lower incidence of lumbosacral spine symptoms in those players who displayed hyperconcavity of the vertebral endplates (16%) versus those who did not (25%), and (3) when hyperconcavity of the vertebral endplates was present, all 5 lumbosacral disk spaces were commonly affected. CONCLUSIONS: Hyperconcavity of the vertebral endplates and hypertrophy of the disk space are likely adaptive changes occurring over time in response to the repetitive high loading and axial stress experienced in football line play.

Osteochondral defects in the human knee: influence of defect size on cartilage rim stress and load redistribution to surrounding cartilage.

PURPOSE: To determine the influence of osteochondral defect size on defect rim stress concentration, peak rim stress, and load redistribution to adjacent cartilage over the weightbearing area of the medial and lateral femoral condyles in the human knee. METHODS: Eight fresh-frozen cadaveric knees were mounted at 30 degrees of flexion in a materials testing machine. Digital electronic pressure sensors were placed in the medial and lateral compartments of the knee. Each intact knee was first loaded to 700 N and held for 5 seconds. Dynamic pressure readings were recorded throughout the loading and holding phases. Loading was repeated over circular osteochondral defects (5, 8, 10, 12, 14, 16, 18, and 20 mm) in the 30 degrees weightbearing area of the medial and lateral femoral condyles. RESULTS: Stress concentration around the rims of defects 8 mm and smaller was not demonstrated, and pressure distribution in this size range was dominated by the menisci. For defects 10 mm and greater, distribution of peak pressures followed the rim of the defect with a mean distance from the rim of 2.2 mm on the medial condyle and 3.2 mm on the lateral condyle. An analysis of variance with Bonferroni correction revealed a statistically significant trend of increasing radius of peak pressure as defect size increased for defects from 10 to 20 mm (P = .0011). Peak rim pressure values did not increase significantly as defects were enlarged from 10 to 20 mm. Load redistribution during the holding phase was also observed. CONCLUSIONS: Rim stress concentration was demonstrated for osteochondral defects 10 mm and greater in size. This altered load distribution has important implications relating to the long-term integrity of cartilage adjacent to osteochondral defects in the human knee. Although the decision to treat osteochondral lesions is certainly multifactorial, a size threshold of 10 mm, based on biomechanical data, may be a useful adjunct to guide clinical decision making.

Traumatic posterior hip subluxation in American football.

BACKGROUND: Traumatic posterior hip subluxation is a potentially devastating injury that is often misdiagnosed as a simple hip sprain or strain. The purpose of the present study was to outline the injury mechanism, pathoanatomy, clinical and radiographic findings, and treatment of traumatic hip subluxation in an athletic population. METHODS: Over a nine-year period, eight participants in American football who had sustained a traumatic posterior hip subluxation were evaluated and treated. The injury mechanism, clinical findings, and radiographic findings were reviewed. The mean duration of follow-up was thirty-four months. RESULTS: The most common mechanism of injury was a fall on a flexed, adducted hip. Physical examination revealed painful limitation of hip motion. Initial radiographs demonstrated a characteristic posterior acetabular lip fracture. Initial magnetic resonance images revealed disruption of the iliofemoral ligament, hemarthrosis, and a viable femoral head. Two players were treated acutely with hip aspiration, and all eight players were treated with a six-week regimen of toe-touch weight-bearing with use of crutches. Six players recovered and returned to the previous level of competition. Two players had development of severe osteonecrosis and ultimately required total hip arthroplasty. CONCLUSION: The pathognomonic radiographic and magnetic resonance imaging triad of posterior acetabular lip fracture, iliofemoral ligament disruption, and hemarthrosis defines traumatic posterior hip subluxation. Patients in whom large hemarthroses are diagnosed on magnetic resonance images should undergo acute aspiration, and all players should be treated with a six-week regimen of toe-touch weight-bearing with use of crutches. Patients who have no sign of osteonecrosis on magnetic resonance imaging at six weeks can safely return to sports activity. Patients in whom osteonecrosis is diagnosed at six weeks are at risk for collapse and joint degeneration, and they should be advised against returning to sports.