Thomas N. Lindenfeld

The Effect of Neuromuscular Training on the Incidence of Knee Injury in Female Athletes A Prospective Study

To prospectively evaluate the effect of neuromuscular training on the incidence of knee injury in female athletes, we monitored two groups of female athletes, one trained before sports participation and the other not trained, and a group of untrained male athletes throughout the high school soccer, volleyball, and basketball seasons. Weekly reports included the number of practice and competition exposures and mechanism of injury. There were 14 serious knee injuries in the 1263 athletes tracked through the study. Ten of 463 untrained female athletes sustained serious knee injuries (8 noncontact), 2 of 366 trained female athletes sustained serious knee injuries (0 noncontact), and 2 of 434 male athletes sustained serious knee injuries (1 noncontact). The knee injury incidence per 1000 athlete-exposures was 0.43 in untrained female athletes, 0.12 in trained female athletes, and 0.09 in male athletes (P 0.02, chi-square analysis). Untrained female athletes had a 3.6 times higher incidence of knee injury than trained female athletes (P 0.05) and 4.8 times higher than male athletes (P 0.03). The incidence of knee injury in trained female athletes was not significantly different from that in untrained male athletes (P 0.86). The difference in the incidence of noncontact injuries between the female groups was also significant (P 0.01). This prospective study demonstrated a decreased incidence of knee injury in female athletes after a specific plyometric training program.

Association Between the Menstrual Cycle and Anterior Cruciate Ligament Injuries in Female Athletes

Anterior cruciate ligament injury rates are four to eight times higher in women than in men. Because of estrogens direct effect on collagen metabolism and behavior and because neuromuscular performance varies during the menstrual cycle, it is logical to question the menstrual cycles 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.

Incidence of Injury in Indoor Soccer

All injuries occurring over a 7-week period at a local indoor soccer arena were documented for analysis of incidence rates. All injury rates were calculated per 100 player-hours. The overall injury rates for male and fe male players were similar, 5.04 and 5.03, respectively. The lowest injury rate was found among the 19- to 24- year-old athletes and the highest injury rate was found among the oldest age group (≥25 years). Collision with another player was the most common activity at the time of injury, accounting for 31 % of all injuries. The most common injury types were sprains and muscle contu sions, both occurring at a rate of 1.1 injuries per 100 player-hours. Male players suffered a significantly higher rate of ankle ligament injuries compared with fe male players (1.24 versus 0.43, P< 0.05), while female players suffered a significantly higher rate of knee liga ment injuries (0.87 versus 0.29, P< 0.01). Goalkeepers had injury rates (4.2) similar to players in nongoalkeeper positions (4.5).

The Effect of the Menstrual Cycle on Anterior Cruciate Ligament Injuries in Women as Determined by Hormone Levels

Anterior cruciate ligament injury rates are reported to be two to eight times higher in women than in men within the same sport. Because the menstrual cycle with its monthly hormonal fluctuations is one of the most basic differences between men and women, we investigated the association between the distribution of confirmed anterior cruciate ligament tears and menstrual cycle phase. Sixty-nine female athletes who sustained an acute anterior cruciate ligament injury were studied within 24 hours of injury at four centers. The mechanism of injury, menstrual cycle details, use of oral contraceptives, and history of previous injury were recorded. Urine samples were collected to validate menstrual cycle phase by measurement of estrogen, progesterone, and luteinizing hormone metabolites and creatinine levels at the time of the anterior cruciate ligament tear. Results from the hormone assays indicate that the women had a significantly greater than expected percentage of anterior cruciate ligament injuries during midcycle (ovulatory phase) and a less than expected percentage of those injuries during the luteal phase of the menstrual cycle. Oral contraceptive use diminished the significant association between anterior cruciate ligament tear distribution and the ovulatory phase.

Joint loading with valgus bracing in patients with varus gonarthrosis

The purpose of this study was to determine whether a brace designed to unload varus degenerative knees actually alters medial compartment loads by decreasing the adduction moment. Eleven patients who had arthrosis confined to the medial compartment were fitted with a valgus brace and tested before and after brace wear with pain and function scoring instruments and by automated gait analysis. The biomechanical data from these patients were compared with those from 11 healthy control subjects. Scores from an analog pain scale decreased 48% with brace wear, and function with activities of daily living increased 79%. Mean adduction moment without the brace measured 4.0 ± 0.8% body weight times height versus 3.6 ± 0.8% body weight times height when wearing the brace (10% decrease). The mean adduction moment for control subjects was 3.5 ± 0.6% body weight times height. Thus, the mean adduction moment decreased from approximately one standard deviation from the normal mean to a value that is similar to the control value. Nine of 11 patients had a decrease in the adduction moment with the brace, five of 11 patients had a reduction higher than 10%, and decreases in this moment were as high as 32%. This study shows that pain, function, and biomechanical knee loading can be altered by a brace designed to unload the medial compartment of the knee.

Medial approach in elbow arthroscopy

The author undertook a cadaveric dissection study to confirm the hypothesis that starting with the anterior medial portal in elbow arthroscopy is safer than starting with the anterior radial portal. In six cadaveric elbows, the capsule was distended with saline. Both anterior medial and anterior radial approaches were made with the elbow flexed to 90°. Four and one-half millimeter arthroscopic sheaths were inserted and obturators were then left in place while the saline was drained; expanding polyurethane foam was used to distend the capsule. We allowed the polyurethane foam to harden and then dissected all elbows, with special attention given to exposure of the radial and medial nerve and the brachial artery. The hardened foam allowed for continued capsular distension during these dissections and recreated nor mal distances from instrument portals to neurovascular bundles. The minimum distance from the path of the arthroscopic sheath to the large neurovascular struc tures was then measured. The distance from the medial portal to the nearest neurovascular structure (median nerve, brachial artery) averaged 23 mm. The distance from the radial portal to the nearest neurovascular structure (radial nerve) averaged 3 mm. The ulnar nerve averaged a 25 mm clearance from the medial portal. Even when the medial portal was made by an incorrect method, the minimum clearance to the median nerve averaged 11 mm. The most frequently recommended current standard technique for elbow arthroscopy involves beginning with an anterior radial portal. However, the findings in this study suggest that an anterior medial portal is a superior starting point. The medial portal allows good visualization of the joint and helps with safe and accu rate placement of the radial portal. Most importantly, the medial portal may be placed a safe distance from important neurovascular bundles.

Knee and hip loading patterns at different phases in the menstrual cycle: implications for the gender difference in anterior cruciate ligament injury rates.

Background Menstrual cycle phase has been correlated with risk of noncontact anterior cruciate ligament injury in women. The mechanism by which hormonal cycling may affect injury rate is unknown. Hypotheses Jumping and landing activities performed during different phases of the menstrual cycle lead to differences in foot strike knee flexion, as well as peak knee and hip loads, in women not taking an oral contraceptive but not in women taking an oral contraceptive. Women will experience greater normalized joint loads than men during these activities. Study Design Controlled laboratory study. Methods Twenty-five women (13 using oral contraceptives) and 12 men performed repeated trials of a horizontal jump, vertical jump, and drop from a 30-cm box on the left leg. Lower limb kinematics (foot strike knee flexion) and peak externally applied moments were calculated (hip adduction moment, hip internal rotation moment, knee flexion moment, knee abduction moment). Men were tested once. Women were tested twice for each phase of the menstrual cycle (follicular, luteal, ovulatory), as determined from serum analysis. An analysis of variance was used to examine differences between phases of the menstrual cycle and between groups (α = .05). Results No significant differences in moments or knee angle were observed between phases in either female group or between the 2 female groups or between either female group and the male controls. Conclusions Variations of the menstrual cycle and the use of an oral contraceptive do not affect knee or hip joint loading during jumping and landing tasks. Clinical Relevance Because knee and hip joint loading is unaffected by cyclic variations in hormone levels, the observed difference in injury rates is more likely attributable to persistent differences in strength, neuromuscular coordination, or ligament properties.

Instructional Course Lectures, The American Academy of Orthopaedic Surgeons - Reflex Sympathetic Dystrophy and Pain Dysfunction in the Lower Extremity*†

Most orthopaedic surgeons have faced the challenge of managing patients who have marked limitation of motion of the knee. Others have managed patients who have a disability because of sympathetically maintained pain—that is, reflex sympathetic dystrophy. Both of these conditions can be difficult to treat. When sympathetically maintained pain and severe contractures occur together in the knee, the problems of diagnosis and treatment are magnified. Sympathetically maintained pain can be disproportionately severe and associated with periarticular swelling as well as with muscle inhibition23,47, which may lead to a slow and painful course in physical therapy. The relative lack of progress in rehabilitation of the knee, as well as the sympathetically maintained pain itself, frequently produce anxiety and depression in these patients, which can lead to poor compliance and worsening stiffness. Increasing stiffness in the knee often limits the ability of a patient to walk, kneel, climb, sit, work, or participate in sports activities and leads to additional emotional stress and upset. As the depression worsens, a vicious cycle results. Unless early and appropriate measures are taken to break the cycle, both the patient and the treating physician will be faced with anger, frustration, and ultimately, an unsatisfactory outcome. Although hand surgeons have long dealt with sympathetically maintained pain the upper extremity14, the syndrome has not been as well recognized or treated as frequently in the lower extremity9,15,33,40. However, recent reports2,5,10,11,20,23,25 have helped to delineate sympathetically maintained pain in the lower extremity, and we now have a better understanding of the pathophysiology and treatment of the condition. The keystone of treatment for this type of stiff and painful knee is early recognition27. …

Instructional Course Lectures, The American Academy of Orthopaedic Surgeons - Operative Treatment of Arthrofibrosis of the Knee*†

The term arthrofibrosis has been used to describe a spectrum of knee conditions in which loss of motion is the major finding18,25,33,35,38,41-43,45. Because different characteristics have been used historically to define this term18,25,33,35,38,41-43,45, the universally accepted definition of this condition remains in question. We believe that arthrofibrosis is best defined as a condition of restricted knee motion characterized by dense proliferative scar formation, in which intra-articular and extra-articular adhesions can progressively spread to limit joint motion. This dense scar tissue can obliterate the parapatellar recesses, suprapatellar pouch, intercondylar notch, and eventually the articular surfaces9. Scarring of the infrapatellar fat pad and fibrosis of the patellar ligament can occur, with varying degrees of capsular and quadriceps contracture. Patella infera and chronic patellar entrapment may also develop as a consequence of this process9. We consider loss of motion that is due to a localized intra-articular lesion as a separate clinical entity. Many patients who have this condition primarily lack full extension as the result of a so-called cyclops lesion22 or other anterior intra-articular scarring following reconstruction of the anterior cruciate ligament9. Normal knee motion has been described as 0 degrees of extension to 135 degrees of flexion, although hyperextension is frequently present to varying degrees4. In general, however, the best way to ascertain normal motion is to examine the contralateral knee if it has no abnormal conditions. Maintaining a full range of knee motion requires congruent articular surfaces; adequate muscle function; an articular capsule with suitable capacity and flexibility; effective space in the medial and lateral articular recesses, intercondylar notch, and …

Spinal Process Apophysitis Mimics Spondylolysis Case Reports

Overuse injuries of the spine commonly occur in gymnasts. According to Garrick and Requa, 13% (14 of 106) of gymnastic injuries occur in the spine and trunk. Similarly, the retrospective study by Dixon and Fricker noted that 16% (52 of 331) of injuries in 74 elite Australian female gymnasts occurred in the spine. Often, gymnasts suffer from spondylolytic injuries that require them to discontinue practice sessions for long periods of time and, occasionally, to end careers prematurely. These injuries may have ominous sequelae. We describe two cases of spinous process physeal injuries in competitive gymnasts that mimicked spondylolysis but appeared to have a faster recovery and a benign course. These spinous process injuries have not been previously described in the English scientific literature.