bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of the Femoral Tunnel Location and Angle on the Contact Pressure in the Femoral Tunnel in Anterior Cruciate Ligament Reconstruction
Authors: Segawa Hiroyuki , Koga Yoshio , Omori Go , Sakamoto Makoto , Hara Toshiaki
Published: July 2017

Background

The causes of bone tunnel enlargement after anterior cruciate ligament reconstruction have not been thoroughly investigated.

Hypothesis

A malpositioned femoral tunnel and an acute femoral tunnel angle may increase the mechanical stress in the femoral tunnel.

Study Design

Controlled laboratory study.

Methods

Three femoral tunnels (normal, anterior, and acute) and the tibial tunnel were made in four fresh-frozen cadaveric knees. Aluminum cylinders containing pressure-sensitive conductive rubber sensors at the joint entrance were inserted into the femoral tunnels. Dynamic changes in the contact pressure of the graft in the femoral tunnel were measured.

Results

Peak contact pressures and dynamic changes in contact pressure for the normal and anterior femoral tunnels demonstrated no differences. Maximum contact pressure of the graft was observed at the anterior portion with the knee in full extension and at the posterior portion with deep knee flexion. Consistent contact pressure occurred at the anterior aspect of the acute femoral tunnel throughout the range of motion. Mean contact pressure at the anterior region of the acute femoral tunnel was significantly higher than that of the normal femoral tunnel at 60°, 90°, and 120° of knee flexion.

Conclusions

The consistent contact pressure in the anterior aspect of the acute femoral tunnel may erode the anterior portion of the femoral tunnel, resulting in bone tunnel enlargement.

Clinical Relevance

The femoral tunnel direction in anterior cruciate ligament reconstruction is an important factor in reducing femoral tunnel enlargement.
Differences in Kinematics and Electromyographic Activity between Men and Women during the Single-Legged Squat
Authors: Zeller Brian L. , McCrory Jean L. , Ben Kibler W. , Uhl Timothy L.
Published: July 2017

Background

Numerous factors have been identified as potentially increasing the risk of anterior cruciate ligament injury in the female athlete. However, differences between the sexes in lower extremity coordination, particularly hip control, are only minimally understood.

Hypothesis

There is no difference in kinematic or electromyographic data during the single-legged squat between men and women.

Study Design

Descriptive comparison study.

Methods

We kinematically and electromyographically analyzed the single-legged squat in 18 intercollegiate athletes (9 male, 9 female). Subjects performed five single-legged squats on their dominant leg, lowering themselves as far as possible and then returning to a standing position without losing balance.

Results

Women demonstrated significantly more ankle dorsiflexion, ankle pronation, hip adduction, hip flexion, hip external rotation, and less trunk lateral flexion than men. These factors were associated with a decreased ability of the women to maintain a varus knee position during the squat as compared with the men. Analysis of all eight tested muscles demonstrated that women had greater muscle activation compared with men. When each muscle was analyzed separately, the rectus femoris muscle activation was found to be statistically greater in women in both the area under the linear envelope and maximal activation data.

Conclusions

Under a physiologic load in a position commonly assumed in sports, women tend to position their entire lower extremity and activate muscles in a manner that could increase strain on the anterior cruciate ligament.
Athletic Injuries of the Wrist and Hand
Authors: Rettig Arthur C.
Published: July 2017

Hand and wrist injuries in sports are some of the most common injuries reported. This review discusses briefly the causes of hand and wrist injuries in sports and discusses pertinent biomechanical findings regarding the range of motion required in different sports activities. The bulk of the review discusses specific traumatic and overuse injuries to the hand and wrist commonly seen in the athlete. Emphasis is placed on problematic traumatic injuries such as carpal scaphoid fractures and hook of the hamate fractures, as well as ligament injuries to the wrist with regard to diagnosis, treatment, and return to athletic competition.
Catastrophic Cheerleading Injuries
Authors: Boden Barry P. , Tacchetti Robin , Mueller Frederick O.
Published: July 2017

Background: There are few epidemiologic studies of cheerleading injuries.

Purpose: To develop a profile of catastrophic injuries in cheerleading and to describe relevant risk factors.

Study Design: Retrospective cohort study.

Methods: We reviewed 29 of 39 incidents of cheerleading injuries reported to the National Center for Catastrophic Sports Injury Research from 1982 to 2002.

Results: Twenty-seven of the injured cheerleaders were women. There were 1.95 direct catastrophic injuries per year or 0.6 injuries per 100,000 participants. The rate of injuries among college cheerleaders was five times that of high school participants. The most common stunts performed at the time of injury were a pyramid (9) or a basket toss (8). Catastrophic injuries included 17 severe head injuries, resulting in 13 skull fractures and 2 deaths; 8 cervical fractures or major ligament injuries; 3 spinal cord contusions; and 1 concomitant head injury and cervical fracture.

Conclusions: Suggestions for reducing catastrophic injuries in cheerleaders include enhancing the number and training of spotters, mandating floor mats for complex stunts, restricting complex stunts when surfaces are wet, and encouraging safety certification of coaches. Pyramids and basket tosses should be limited to experienced cheerleaders who have mastered all other skills and should be performed with spotters and landing mats.
Prospective Comparison of Arthroscopic Medial Meniscal Repair Technique
Authors: Spindler Kurt P. , McCarty Eric C. , Warren Todd A. , Devin Clinton , Connor Jason T.
Published: July 2017

Background: Medial meniscal repairs are commonly performed with inside-out sutures and entirely arthroscopic with arrows, but few comparative evaluations on failures have been performed.

Hypothesis: No differences in failure rates exist between medial meniscal repairs performed with inside-out suture or entirely arthroscopic at the time of anterior cruciate ligament reconstruction.

Study Design: Prospective cohort study.

Materials: A single surgeon performed 47 consecutive inside-out suture repairs from August 1991 to June 1996 and 98 consecutive entirely arthroscopic repairs with arrows from June 1996 to December 1999. All data were derived from a prospective database and rehabilitation was held constant (nonweightbearing 5 weeks). Clinical success was defined as no reoperation for failed medial meniscal repair. Statistical evaluation was by Kaplan-Meier curves and Cox proportional hazards model.

Results: The inside-out suture group had 85% follow-up (40 of 47) with a median 68 months and the entirely arthroscopic group had 87% follow-up (85 of 98) with a median 27 months. There were seven failures in each group. Both Kaplan-Meier curves and the Cox proportional hazards model showed no difference in time to reoperation between techniques (P = 0.85). Three-year success rates (proportions with no reoperations) were 88% for sutures versus 89% for arrows.

Conclusions: Repairs of the longitudinal posterior horn of the medial meniscus during an anterior cruciate ligament reconstruction with nonweightbearing for 5 weeks can be performed with an equivalent high degree of clinical success for both repair techniques.
Diagnostic and Prognostic Value of Clinical Findings in 83 Athletes with Posterior Thigh Injury
Authors: Verrall Geoffrey M. , Slavotinek John P. , Barnes Peter G. , Fon Gerald T.
Published: July 2017

Background

Little is known about the clinical features of posterior thigh injuries and their contribution to accurate diagnosis and prognostic assessment of hamstring muscle strain injury.

Hypotheses

The clinical features of posterior thigh injury can be used to diagnose hamstring muscle strain and to predict duration of absence from competition.

Study Design

Prospective clinical study.

Methods

For two playing seasons, the clinical features of posterior thigh injury, timing of injury, and playing days lost were recorded for Australian Rules football players. Magnetic resonance imaging was used to confirm hamstring muscle injury.

Results

Posterior thigh injuries associated with pain and tenderness were recorded for 83 players, with magnetic resonance imaging confirming hamstring injury in 68 (82%). Most of the hamstring injuries were sudden onset (62; 91%) and occurred after a significant warm-up period (57; 84%). Of the patients whose injuries were sudden onset and occurred after the warm-up period (N = 59), 57 (97%) had hamstring muscle strain detected on magnetic resonance imaging. Hamstring muscle injury confirmed by magnetic resonance imaging was associated with a longer absence from competition (mean, 27 days) than injuries where no hamstring injury was detected (mean, 16 days).

Conclusions

The clinical features of hamstring injury typically include sudden onset, pain, and tenderness, although exceptions do occur. Muscle fatigue may be important in the pathogenesis of hamstring injury.
The Effects of Muscle Fatigue on Shoulder Joint Position Sense
Authors: Carpenter James E. , Blasier Ralph B. , Pellizzon Gregory G.
Published: July 2017

Proprioception, or joint position sense, probably plays an important role in shoulder joint function. In this study, we assessed the effect of muscle fatigue on shoulder proprioception in 20 volunteers with no shoulder abnormalities. Shoulder proprioception was measured as the threshold to first detection of humeral rotation with the joint at 90° of abduction and 90° of external rotation. Subjects were tested while rested, exercised on a isokinetic testing machine until fatigued, and then retested in an identical fashion. Both shoulders were tested, and the order of dominant and non-dominant shoulder was randomized. Shoulder proprioception was analyzed for its dependence on arm dominance, direction of rotation, and muscle fatigue. Subjects detected external rotation after significantly less movement than they did internal rotation. Overall, before exercise, motion was detected after a mean of 0.92° of rotation. After exercise, this threshold to detection of movement increased to 1.59°, an increase of 73%. This significant increase occurred with both internal and external rotation. The decrease in proprioceptive sense with muscle fatigue may play a role in decreasing athletic performance and in fatigue-related shoulder dysfunction. It remains to be determined if training can lessen this loss in position sense.
The Snowboarder's Foot and Ankle
Authors: Kirkpatrick Douglas P. , Hunter Robert E. , Janes Peter C. , Mastrangelo Jackie , Nicholas Richard A.
Published: July 2017

We undertook a prospective study to determine the type and distribution of foot and ankle snowboarding injuries. Reports of 3213 snowboarding injuries were collected from 12 Colorado ski resorts between 1988 and 1995. Of these, 491 (15.3%) were ankle injuries and 58 (1.8%) were foot injuries. Ankle injuries included 216 (44%) fractures and 255 (52%) sprains. Thirty-three (57%) of the foot injuries were fractures and 16 (28%) were sprains. The remaining injuries were soft tissue injuries, contusions, or abrasions. There was no significant correlation between boot type (soft, hybrid, or hard) and overall foot or ankle injury rate. There were significantly fewer ankle sprains in patients wearing hybrid boots and fewer fractures of the lateral process of the talus in patients wearing soft boots. An unexpectedly high number of fractures of the lateral process of the talus were noted. These 74 fractures represented 2.3% of all snowboarding injuries, 15% of all ankle injuries, and 34% of the ankle fractures. Many of these fractures are not visible on plain radiographs and require computed tomography imaging to be diagnosed. Diagnosis of this fracture pattern is paramount; the physician should be very suspicious of anterolateral ankle pain in the snowboarder, where subtle fractures that may require surgical intervention can be confused with anterior talofibular ligament sprains.
Results of Derotational Humeral Osteotomy in Posterosuperior Glenoid Impingement
Authors: Riand Nicolas , Levigne Christophe , Renaud Eric , Walch Gilles
Published: July 2017

We identified 20 throwing athletes who continued to have pain after articular debridement for posterosuperior impingement syndrome. These patients were unable to resume sports, and we subsequently performed a derotational humeral osteotomy with a myorraphy of the subscapularis muscle. Patients were observed for an average of 46 months (range, 12 to 69). Eleven patients were able to resume the same sport at the same level, five resumed the same sport at a lower level, three changed sport secondary to persistent pain, and the last patient did not resume any sport and was worse after surgery. Patients returned to sports at an average of 6 months postoperatively (range, 4 to 44) and to their previous level of sports at an average of 12 months (range, 8 to 18). The mean increase in humeral retroversion was 29° (range, 18° to 44°). Three women with preoperative multidirectional hyperlaxity were considered to have failed results. Derotational humeral osteotomy can be considered in the throwing athlete with posterosuperior impingement after failure of all other means of treatment. Careful patient selection and preoperative evaluation of humeral retroversion is important. Best results can be achieved in a motivated patient with low retroversion ( 10°). If retroversion is normal (20° to 30°), the surgical indication is unclear. We do not recommend this surgery for patients with hyperlaxity.
Association Between the Menstrual Cycle and Anterior Cruciate Ligament Injuries in Female Athletes
Authors: Wojtys Edward M. , Huston Laura J. , Lindenfeld Thomas N. , Hewett Timothy E. , Greenfield Mary Lou V. H.
Published: July 2017

Anterior cruciate ligament injury rates are four to eight times higher in women than in men. Because of estrogen's direct effect on collagen metabolism and behavior and because neuromuscular performance varies during the menstrual cycle, it is logical to question the menstrual cycle's effect on knee injury rates. Of 40 consecutive female athletes with acute anterior cruciate ligament injuries (less than 3 months), 28 (average age, 23 11 years) met the study criteria of regular menstrual periods and noncontact injury. Details concerning mechanism of injury, menstrual cycle, contraceptive use, and previous injury history were collected. A chi-square test was used to compute observed and expected frequencies of anterior cruciate ligament injury based on three different phases of the menstrual cycle: follicular (days 1 to 9), ovulatory (days 10 to 14), and luteal (day 15 to end of cycle). A significant statistical association was found between the stage of the menstrual cycle and the likelihood for an anterior cruciate ligament injury (P 0.03). In particular, there were more injuries than expected in the ovulatory phase of the cycle. In contrast, significantly fewer injuries occurred in the follicular phase. These hormones may be a factor in the knee ligament injury dilemma in women.
Analysis of Collagen and Elastic Fibers in Shoulder Capsule in Patients with Shoulder Instability
Authors: Rodeo Scott A. , Suzuki Katsunori , Yamauchi Mitsuo , Bhargava Madhu , Warren Russell F.
Published: July 2017

This study examined collagen cross-links, collagen fibril diameter and density, amino acid composition, and elastic fibers in shoulder capsule and skin in four patient groups: 1) unidirectional anterior instability (N 8); 2) multidirectional instability/primary surgery (N 6); 3) multidirectional instability/revision surgery (N 6); and 4) no history of instability (N 5). Compared with normal capsule, capsule from groups 1 and 2 had more stable and reducible collagen cross-links, significantly greater mean collagen fibril diameter, more cysteine, and a higher density of elastin staining. Compared with shoulder capsule in groups 1 and 2, shoulder capsule from group 3 contained significantly more reducible cross-links, smaller-diameter collagen fibrils, decreased collagen fibril density, and an increased density of elastin staining. There were no significant differences in any parameters between groups 1 and 2. We hypothesized that repeated capsular deformation in patients with shoulder instability results in changes in the capsule that increase its strength and resistance to stretching. Skin analyses demonstrated a significantly smaller mean collagen fibril diameter in skin from group 2 compared with group 1, suggesting the possibility of an underlying connective tissue abnormality.
Injuries in Collegiate Wrestling
Authors: Jarrett Glenn J. , Orwin John F. , Dick Randall W.
Published: July 2017

We evaluated the data of the National Collegiate Athletic Association Injury Surveillance System on collegiate wrestling with a focus on musculoskeletal injuries. Over 800,000 athlete-exposures during an 11-year period compose these data. Findings particular to wrestling and a comparison with other collegiate sports are included. Collegiate wrestling had a relatively high rate of injury at 9.6 injuries per 1000 athlete-exposures. It was second to spring football in total injury rate. Most injuries in this study were not serious, with 6.3% resulting in surgery and 37.6% resulting in a week or more off from wrestling. There was only one catastrophic, nonfatal injury. The knee, shoulder, and ankle were the most commonly injured regions, and injuries to them were often the more serious. Sprains, strains, and contusions were the most common injury types. Takedowns and sparring were the most common activities at the time of injury. Mechanism of injury was evaluated; rotation about a planted foot and contact with environmental objects were identified as areas needing further attention. Illegal action accounted for only 4.6% of injuries in competition. Competition had a significantly higher injury rate than practice, but the injury profiles of these two areas showed both to be equally important. The preseason and regular season had higher injury rates than the postseason, but, again, the injury profiles of these periods were similar. Injury percentages were similar among the 10 weight classes.
Conscious Neurosensory Mapping of the Internal Structures of the Human Knee Without Intraarticular Anesthesia
Authors: Dye Scott F. , Vaupel Geoffrey L. , Dye Christopher C.
Published: July 2017

The conscious neurosensory characteristics of the internal components of the human knee were documented by instrumented arthroscopic palpation without intraarticular anesthesia. With only local anesthesia injected at the portal sites, the first author (SFD) had both knees inspected arthroscopically. Subjectively, he graded the sensation from no sensation (0) to severe pain (4), with a modifier of either accurate spatial localization (A) or poor spatial localization (B). The nature of the intraarticular sensation was variable, ranging from 0 on the patellar articular cartilage to 4A on the anterior synovium, fat pad, and joint capsule. The sensation arising from the cruciate ligaments ranged from 1 to 2B in the midportion, and from 3 to 4B at the insertion sites. The sensation from the meniscal cartilages ranged from 1B on the inner rim to 3B near the capsular margin. Innervation of most intraarticular components of the knee is probably crucial for tissue homeostasis. Failure of current intraarticular soft tissue reconstructions of the knee may be due, in part, to the lack of neurosensory restoration. Research studies of the knee designed to delineate factors that restore neurosensory characteristics of the musculoskeletal system may lead to techniques that result in true restoration of joint homeostasis and function.
Functional Knee Brace Effects During Walking in Patients With Anterior Cruciate Ligament Reconstruction
Authors: DeVita Paul , Lassiter Tally , Hortobagyi Tibor , Torry Michael
Published: July 2017

The purpose of this study was to compare lower extremity joint kinematics and kinetics during walking with and without a functional knee brace in patients with recent anterior cruciate ligament reconstructions. Seven volunteers walked at 1.26 m/s with and without one of two functional knee braces 3 weeks after surgery. Eleven uninjured subjects were also tested as a control group. Video and ground-reaction data were collected and combined with inverse dynamics to estimate the joint positions, moments, and powers during the stance phase. Patients with ligament reconstructions were more erect with the brace, using 19% less knee flexion compared with walking without the brace. Areas under the internal extensor moment curve (angular impulse) and power curve (work) at the hip increased 40% and 44%, respectively, while walking with the brace. Extensor angular impulse decreased 41% at the knee while using the brace, and plantar flexor angular impulse and work increased 21% and 30%, respectively, at the ankle. While walking with the brace, the patients still had different kinematics, moments, and powers than the control subjects. The reduced extensor moment at the knee in the braced condition indicated that the load on the recently reconstructed ligament was reduced and that the brace protected the ligament during the stance phase of walking. We concluded that functional knee braces may be one means of developing neuromuscular adaptations during gait after anterior cruciate ligament reconstruction surgery.
The Effects of Overuse Combined With Intrinsic or Extrinsic Alterations in an Animal Model of Rotator Cuff Tendinosis
Authors: Carpenter James E. , Flanagan Colleen L. , Thomopoulos Stavros , Yian Edward H. , Soslowsky Louis J.
Published: July 2017

An in vivo animal model was used to evaluate overuse and overuse plus intrinsic tendon injury or extrinsic tendon compression in the development of rotator cuff injury. Forty-four male Sprague-Dawley rats were divided into groups of 22. Each left shoulder received an intrinsic or extrinsic injury plus overuse (treadmill running), and each right shoulder received only overuse. Eleven rats from each group were sacrificed at 4 and 8 weeks. Supraspinatus tendons were evaluated histologically or geometrically and biomechanically. Ten rats constituted a cage-activity control group. Both supraspinatus tendons of the experimental groups had increases in cellularity and collagen disorganization and changes in cell shape compared with control tendons. Tendons with injury plus overuse exhibited a worse histologic grade than those with overuse alone. The cross-sectional area of both supraspinatus tendons of the experimental rats was significantly more than in control tendons. The area of the injury plus overuse tendons was increased on average compared with overuse-alone tendons. Biomechanically, the tissue moduli of overuse/intrinsic injury tendons at 4 weeks and those of the overuse/extrinsic injury tendons at 8 weeks were significantly lower than in control tendons. Tissue moduli of the overuse/injury tendons were significantly lower than in the overuse-alone tendons at 8 weeks. This study demonstrated that damage to the supraspinatus tendon can be caused by overuse and intrinsic injury, overuse and extrinsic compression, and overuse alone.
Open Meniscal Repair: Clinical and Magnetic Resonance Imaging Findings After Twelve Years
Authors: Muellner Thomas , Egkher Alexander , Nikolic Ajsa , Funovics Martin , Metz Viktor
Published: July 2017

The purpose of this study was to document the long-term clinical, radiographic, and magnetic resonance imaging results after open meniscal repair. Twenty-two patients, with 23 open meniscal repairs, were evaluated after a mean follow-up of 12.9 years using patient history, physical examination, KT-1000 arthrometer testing, the “Orthopaedische Arbeitsgemeinschaft Knie” knee evaluation scheme, Tegner activity score, weightbearing radiographs, and magnetic resonance imaging. Two of the 22 patients had retears and both occurred in unstable knees. Radiographs revealed no degenerative changes in 17 of the 23 compartments. Grade III and IV signal alterations were present on magnetic resonance imaging scans in more than 50% of the repaired menisci. We concluded that the long-term survival rate of repaired menisci was 91%, and that magnetic resonance imaging is unsuitable for diagnosis of the healing process of a repaired meniscus.
Isolation of the Vastus Medialis Oblique Muscle During Exercise
Authors: Mirzabeigi Edwin , Jordan Christopher , Gronley JoAnne K. , Rockowitz Neal L. , Perry Jacquelin
Published: July 2017

The purpose of this study was to selectively challenge the vastus medialis oblique muscle in comparison with the vastus lateralis, the vastus intermedius, and the vastus medialis longus muscles by performing nine sets of strengthening exercises. These knee rehabilitation exercises included isometric knee extension with the hip at neutral, 30° external, and 30° internal rotation; isokinetic knee extension through full range; isokinetic knee extension in the terminal 30° arc; sidelying ipsilateral and contralateral full knee extension; and stand and jump from full squat. Electrical activity of the vastus medialis oblique, the vastus lateralis, the vastus intermedius, and the vastus medialis longus muscles was measured in eight uninjured subjects. Our study showed that isometric exercises in neutral and external rotation of the hip will challenge both the vastus medialis oblique and the vastus lateralis muscles. The results suggest that the electromyographic activity of the vastus medialis oblique muscle was not significantly greater than that of the vastus lateralis, the vastus intermedius, and the vastus medialis longus muscles during the nine sets of exercises. Results suggest that the vastus medialis oblique muscle cannot be significantly isolated during these exercises.
Which is More Useful, the “Full Can Test” or the “Empty Can Test,” in Detecting the Torn Supraspinatus Tendon?
Authors: Itoi Eiji , Kido Tadato , Sano Akihisa , Urayama Masakazu , Sato Kozo
Published: July 2017

The purpose of this study was to determine the clinical usefulness of the full can and empty can tests for determining the presence of a torn supraspinatus tendon. The two tests were performed in 143 shoulders of 136 consecutive patients. In each test, the muscle strength was determined by manual muscle testing, and the presence of pain during the maneuver was recorded. We interpreted the tests as positive when there was 1) pain, 2) muscle weakness, or 3) pain or muscle weakness or both. Shoulders were examined by high-resolution magnetic resonance imaging with 95% accuracy for full-thickness rotator cuff tears. There were 35 shoulders with full-thickness tears of the supraspinatus tendon. The accuracy of the tests was the greatest when muscle weakness was interpreted as indicating a torn supraspinatus tendon in both the full can test (75% accurate) and the empty can test (70% accurate). However, there was no significant difference between the accuracy of the tests when this criterion was used. Pain was observed in 62 shoulders (43%) during the full can test and in 71 shoulders (50%) during the empty can test, but the difference was not statistically significant. Muscle weakness should be interpreted as indicative of supraspinatus tendon tear. Using this indicator, both tests are equivalent in terms of accuracy, but considering pain provocation, the full can test may be more beneficial in the clinical setting.
The Effect of Knee Bracing After Anterior Cruciate Ligament Reconstruction
Authors: Risberg May Arna , Holm Inger , Steen Harald , Eriksson Jan , Ekeland Arne
Published: July 2017

The purpose of this prospective, randomized, clinical trial was to evaluate the effect of knee bracing after anterior cruciate ligament reconstruction. Sixty patients were randomized into one of two groups: Patients in the braced group wore rehabilitative braces for 2 weeks, followed by functional braces for 10 weeks, and patients in the nonbraced group did not wear braces. Data were recorded preoperatively, and postoperatively after 6 weeks, 3 and 6 months, and 1 and 2 years. The following outcome measures were used: KT-1000 arthrometry, the Cincinnati knee score, goniometry to record range of motion, computed tomography to determine thigh atrophy, Cybex 6000 isokinetic testing to evaluate muscle strength, three functional knee tests, and a visual analog scale to evaluate pain. At all follow-up times there were no significant differences between the two groups with regard to knee joint laxity, range of motion, muscle strength, functional knee tests, or pain. However, the Cincinnati knee score showed that patients in the braced group had significantly improved knee function compared with patients in the nonbraced group at the 3-month follow-up, even though the braced group showed significantly increased thigh atrophy compared with the nonbraced group at 3 months.
Injury Risk in First-Time Snowboarders Versus First-Time Skiers
Authors: Fulham O'Neill Daniel , McGlone Mark R.
Published: July 2017

Between 1994 and 1996 we studied injury patterns in more than 22,000 first-time snowboarders and first-time skiers to determine the comparative injury risk of these two popular sports coexisting in winter resort areas. The first-time participants included in this study had no previous experience in their activity of choice and enrolled in Learn to Snowboard and Learn to Ski programs in two major northeastern ski resorts. Data were gathered from physician evaluations at the medical clinics at each mountain. Two hundred seventy-three (4%) of the first-time snowboarders (N 6585), and 641 (4%) of the first-time skiers (N 15,795) sustained an injury. Injuries were further evaluated by location (upper extremity, lower extremity, head, and trunk area) and severity (emergent versus nonemergent). Snowboarders had a higher percentage of upper extremity injuries (53%), while skiers had a higher percentage of lower extremity injuries (63%). Snowboarders, however, sustained a significantly higher incidence of emergent injuries (such as fracture, concussion, dislocation, lost teeth) necessitating immediate intervention. While there have been other reports describing injuries in these activities, no previous study attempted to look at the first-time participants with similar age, experience, and equipment to determine comparative risk. We conclude that for the first-time participant, snowboarding does show a higher incidence of emergent injuries.
Evaluation of Knee Stability Before and After Participation in a Functional Sports Agility Program During Rehabilitation After Anterior Cruciate Ligament Reconstruction
Authors: Shelbourne K. Donald , Davis Thorp J.
Published: July 2017

We sought to determine whether participation in a functional sports agility program as early as 4 weeks after anterior cruciate ligament reconstruction with autogenous patellar tendon graft would affect objective knee stability in 603 patients. The rehabilitation program prescribed a functional sports agility program at a mean of 5.1 1.0 weeks postoperatively when full knee hyperextension, knee flexion to 120°, and quadriceps muscle strength of 60% of the normal leg had been achieved. The patients had KT-1000 arthrometer testing before beginning the program and at subsequent follow-up after they had performed the sport activity. The mean manual maximum KT-1000 arthrometer difference was 1.9 1.3 mm at initial testing and 1.9 1.2 mm at follow-up testing. The frequency distribution of the KT-1000 arthrometer scores revealed that 92.7% of patients at initial testing and 93.2% of patients at follow-up testing had displacement difference of 3 mm or less. The results of this study show that functional sports agility programs during the early rehabilitation period after anterior cruciate ligament reconstruction with a correctly placed autogenous patellar tendon graft do not cause a change in graft stability.
Reconstruction of the Anterior and Posterior Cruciate Ligaments After Knee Dislocation
Authors: Wascher Daniel C. , Becker Jeremy R. , Dexter James G. , Blevins Field T.
Published: July 2017

We reviewed the results in 13 patients who underwent simultaneous allograft reconstruction of both the anterior and posterior cruciate ligaments after a knee dislocation (nine acute and four chronic injuries). Seven patients sustained related medial collateral ligament injuries and six patients had posterolateral complex injuries. Ligament reconstructions were performed using fresh-frozen Achilles or patellar tendon allografts. At follow-up evaluation (mean of 38 months), only one patient described the reconstructed knee as normal. Six patients had returned to unrestricted sports activities and four had returned to modified sports. The average extension loss was 3° (range, 0° to 10°) and average flexion loss was 5° (range, 0° to 15°). The KT-1000 arthrometer measurements at 133 N anterior-posterior tibial load showed a mean side-to-side difference of 4.5 mm (range, 0 to 10) at 20° and 5.0 mm (range, 0 to 9) at 70°. The mean Lysholm score was 88 (range, 42 to 100). International Knee Documentation Committee ratings were six nearly normal, five abnormal, and one grossly abnormal. Two patients required manipulations for knee stiffness. This study demonstrates that reconstruction of both cruciate ligaments can restore stability sufficient to allow sports activity in most patients with knee dislocations, but “normal” results are difficult to achieve.
The Incidence of Injury in Texas High School Basketball
Authors: Messina Douglas F. , Farney William C. , DeLee Jesse C.
Published: July 2017

Recent publications have reported differences in the incidence, rate, risk, and type of sports injury among men and women. We undertook a prospective study to determine the incidence of injury among high school basketball players and to examine the differences in injury type, incidence, rate, and risk between male and female athletes. During a single basketball season, an injury survey of girls' varsity teams at 100 class 4A and 5A high schools in Texas was conducted. These data were previously reported. We surveyed the same 100 high schools during a subsequent season to gather injury data from the boys' varsity teams. The athletic trainer collected data on each reportable injury and reported the data weekly to the University Interscholastic League. A reportable injury was defined as one that occurred during a practice or a game, resulted in missed practice or game time, required physician consultation, or involved the head or the face. The boys' and girls' data were compared and statistically analyzed. The rate of injury was 0.56 among the boys and 0.49 among the girls. The risk of injury per hour of exposure was not significantly different between the two groups. In both groups, the most common injuries were sprains, and the most commonly injured area was the ankle, followed by the knee. Female athletes had a significantly higher rate of knee injuries including a 3.79 times greater risk of anterior cruciate ligament injuries. For both sexes, the risk of injury during a game was significantly higher than during practice.
Magnetic Resonance Imaging as a Tool to Predict Meniscal Reparability
Authors: Matava Matthew J. , Eck Kevin , Totty William , Wright Rick W. , Shively Robert A.
Published: July 2017

One hundred six patients who underwent high field strength magnetic resonance imaging and subsequent arthroscopy of the knee were evaluated to determine the accuracy of magnetic resonance imaging in predicting meniscal tear reparability. Each scan was independently read by three examiners with varying degrees of expertise: a musculoskeletal radiologist, a senior orthopaedic surgeon, and a general radiologist. Each suspected tear was characterized by its morphologic type, maximum length, and minimum distance from the meniscosynovial junction. A prediction was then made of whether the tear was reparable. There were 115 meniscal tears noted in the 106 patients studied. The examiners' ability to correctly estimate tear type was only fair, with correct estimates made only 14% to 67% of the time. The overall correlation of the three examiners to correctly predict the method of treatment was fair. The average accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of magnetic resonance imaging in predicting meniscal reparability were 74%, 29%, 89%, 50%, and 80%, respectively; for predicting meniscectomy, these values were 69%, 68%, 75%, 90%, and 43%, respectively. There were no significant differences between the three examiners in the accuracy of their treatment predictions. The results of this study suggest that magnetic resonance imaging is only moderately reliable for the prediction of meniscus reparability. In addition, the training of the reader does not appear to significantly influence the results.
The Effects of Grade III Posterolateral Knee Complex Injuries on Anterior Cruciate Ligament Graft Force
Authors: LaPrade Robert F. , Resig Scott , Wentorf Fred , Lewis Jack L.
Published: July 2017

To determine if untreated grade III injuries of the posterolateral structures contribute to increased force on an anterior cruciate ligament graft, we measured the force in the graft in cadaveric knees during joint loading after reconstruction with otherwise intact structures and in the same reconstructed knees after selected cutting of specific posterolateral knee structures. Tests were first performed on the knee with the posterolateral structures intact and then after sequential sectioning of the fibular collateral ligament, popliteofibular ligament, and popliteus tendon. The graft force was significantly higher after fibular collateral ligament transection during varus loading at both 0° and 30° of knee flexion than it was for the same loading of the joint with intact posterolateral structures. In addition, coupled loading of varus and internal rotation moments at 0° and 30° of flexion further increased graft force beyond that with varus force alone. The increase in graft force remained significant with additional sequential cutting of the popliteofibular ligament and popliteus tendon. We believe this study supports the clinical observation that untreated grade III posterolateral structure injuries contribute to anterior cruciate ligament graft failure by allowing higher forces to stress the graft.
The Role of Passive Muscle Stiffness in Symptoms of Exercise-Induced Muscle Damage
Authors: McHugh Malachy P. , Connolly Declan A. J. , Eston Roger G. , Kremenic Ian J. , Nicholas Stephen J. , Gleim Gilbert W.
Published: July 2017

We examined whether passive stiffness of an eccentrically exercising muscle group affects the subsequent symptoms of muscle damage. Passive hamstring muscle stiffness was measured during an instrumented straight-leg-raise stretch in 20 subjects (11 men and 9 women) who were subsequently classified as “stiff” (N 7), “normal” (N 6), or “compliant” (N 7). Passive stiffness was 78% higher in the stiff subjects (36.2 3.3 N m rad 1) compared with the compliant subjects (20.3 1.8 N m rad 1). Subjects then performed six sets of 10 isokinetic (2.6 rad s 1) submaximal (60% maximal voluntary contraction) eccentric actions of the hamstring muscle group. Symptoms of muscle damage were documented by changes in isometric hamstring muscle strength, pain, muscle tenderness, and creatine kinase activity on the following 3 days. Strength loss, pain, muscle tenderness, and creatine kinase activity were significantly greater in the stiff compared with the compliant subjects on the days after eccentric exercise. Greater symptoms of muscle damage in subjects with stiffer hamstring muscles are consistent with the sarcomere strain theory of muscle damage. The present study provides experimental evidence of an association between flexibility and muscle injury. Muscle stiffness and its clinical correlate, static flexibility, are risk factors for more severe symptoms of muscle damage after eccentric exercise.
Effects of Hyperbaric Oxygen on a Human Model of Injury
Authors: Staples James R. , Clement Douglas B. , Taunton Jack E. , McKenzie Donald C.
Published: July 2017

To determine whether intermittent exposures to hyperbaric oxygen enhance recovery from delayed-onset muscle soreness of the quadriceps, we conducted a randomized, controlled, double-blinded, prospective study using 66 untrained men between the ages of 18 and 35 years. After the induction of muscle soreness, these subjects were treated in a hyperbaric chamber over a 5-day period in two phases, with four groups (control, hyperbaric oxygen treatment, delayed treatment, and sham treatment) in the first phase; and three groups (3 days of treatment, 5 days of treatment, and sham treatment) in the second phase. The hyperbaric exposures involved 100% oxygen for 1 hour per day at 2.0 atm. The sham treatments involved 21% oxygen for 1 hour per day at 1.2 atm. We monitored recovery using a leg dynamometer to test eccentric torque of the nondominant quadriceps muscle before and immediately after exercise and at 48 and 96 hours after exercise. Pain was tested daily using visual analog pain scales. In phase 1 a significant difference in recovery of eccentric torque was noted in the treatment group compared with the other groups. In phase 2, the recovery of eccentric torque for the 5-day treatment group was significantly greater than for the sham group from immediately after exercise to 96 hours after exercise. The pain data did not differ significantly in any comparison in either phase. The results suggest that treatment with hyperbaric oxygen may enhance recovery of eccentric torque of the quadriceps muscle from delayed-onset muscle soreness.
Monopolar Radiofrequency Energy Effects on Joint Capsular Tissue: Potential Treatment for Joint Instability
Authors: Hecht Paul , Hayashi Kei , Yan Lu  , Fanton Gary S. , Thabit George , Vanderby Ray , Markel Mark D.
Published: July 2017

The purpose of this study was to evaluate the thermal effect of monopolar radiofrequency energy, a potential treatment means for joint instability, on the mechanical, morphologic, and biochemical properties of joint capsular tissue in an in vivo ovine model. The energy was applied arthroscopically to the synovial surface of the femoropatellar joint capsule of 24 sheep. The sheep were sacrificed at 0, 2, 6, and 12 weeks after surgery (6 per group). Monopolar radiofrequency energy initially caused a significant decrease in tissue stiffness and an increase in tissue relaxation properties, followed by gradual improvement in the tissue's mechanical properties by 6 weeks after surgery. Microscopic examination illustrated that radiofrequency energy initially caused collagen hyalinization and cell necrosis, followed by active tissue repair. Biochemical analysis revealed that treated collagen was significantly more trypsin-susceptibile than untreated collagen at 0 and 2 weeks after surgery, indicating early collagen denaturation. This study demonstrated that this treatment initially caused a significantly deleterious effect on the mechanical properties of the joint capsule, which was associated with partial denaturation of joint capsular tissue. This was followed by gradual improvement of the mechanical, morphologic, and biochemical properties of the tissue over time.
The Effect of Cyclic Displacement On the Biomechanical Characteristics of Anterior Cruciate Ligament Reconstructions
Authors: Yamanaka Masanori , Yasuda Kazunori , Tohyama Harukazu , Nakano Hideaki , Wada Tatuhiko
Published: July 2017

This study was conducted to clarify the influence of cyclic displacement on the structural properties of four types of femur-graft-tibia complexes used to reconstruct the anterior cruciate ligament. Forty hindlimbs from pigs were used. In two groups, bone-patellar tendon-bone grafts were secured with interference screws (group A) or the suture-post technique (group B). In two groups, multistrand flexor tendons were fixed using the tape-staple technique (group C) or the sutures-tied-over-a-button technique (group D). In each group, five femur-graft-tibia complexes underwent tensile failure tests without cyclic displacement. The other five complexes underwent 5000 cycles of cyclic elongation for 2 mm, and then underwent the tensile failure tests. The initial stiffness significantly decreased after cyclic displacement in each group, although there were no significant differences in the linear stiffness and the ultimate failure load between the tests with and without cyclic displacement. These findings suggest that 5000 cycles of repetitive elongation of the femur-graft-tibia complex by 2 mm does not jeopardize the graft fixed with the procedures used in this study, despite a slight but significant increase of an anterior-posterior laxity of the knee.
Cyclic Pull-Out Strength of Hamstring Tendon Graft Fixation with Soft Tissue Interference Screws
Authors: Stadelmaier Denise M. , Lowe Walter R. , Ilahi Omer A. , Noble Philip C. , Kohl Harold W.
Published: July 2017

Blunt-threaded interference screws used for fixation of hamstring tendons in anterior cruciate ligament reconstructions provide aperture fixation and may provide a biomechanically more stable graft than a graft fixed further from the articular surface. It is unknown if soft tissue fixation strength using interference screws is affected by screw length. We compared the cyclic and time-zero pull-out forces of 7 25 mm and 7 40 mm blunt-threaded metal interference screws for hamstring graft tibial fixation in eight paired human cadaveric specimens. A four-stranded autologous hamstring tendon graft was secured by a blunt-threaded interference screw into a proximal tibial tunnel with a diameter corresponding to the graft width. Eight grafts were secured with a 25-mm length screw while the other eight paired grafts were secured with a 40-mm length screw. During cyclic testing, slippage of the graft occurred as the force of pull became greater with each cycle until the graft-screw complex ultimately failed. All grafts failed at the fixation site, with the tendon being pulled past the screw. There were no measurable differences in the mean cyclic failure strength, pull-out strength, or stiffness between the two sizes of screws. Although use of the longer screw would make removal technically easier should revision surgery be necessary, it did not provide stronger fixation strength than the shorter, standard screw as had been postulated.
The Value of Weighted Views of the Acromioclavicular Joint
Authors: Yap John J. L. , Curl Leigh Ann , Kvitne Ronald S. , McFarland Edward G.
Published: July 2017

One hundred twelve practicing members of the American Shoulder and Elbow Surgeons in the United States and Canada were surveyed regarding use of weighted views of the acromioclavicular joint. They were also asked about treatment for hypothetical patients seen in the emergency department or office with grade II or III acromioclavicular separations. One hundred five physicians (94%) responded to the survey. Eighty-five members (81%) did not recommend obtaining weighted views in the emergency department. Sixty members (57%) did not use weighted views, and the majority commented that weighted views had no influence on their decision-making regarding treatment. Forty-five members (43%) used weighted views, but most did not use the results of this test to determine surgical intervention. Physicians recommending weighted views averaged 21 years of practice, compared with 16 years for those who did not obtain weighted views. Only nine physicians (9%) had changed treatment on the basis of weighted views. The patient's arm dominance, work, or athletic status did not influence most surgeons' decision to perform surgery when weighted views revealed a grade III separation. We found no correlation between obtaining weighted views and performing surgical reconstruction for patients with grade III acromioclavicular separations.