Stephen J. Nicholas

Quantification of Posterior Capsule Tightness and Motion Loss in Patients with Shoulder Impingement

The relationship between posterior capsule tightness and dysfunction has long been recognized clinically but has not been biometrically quantified. The purpose of this study was to quantify changes in range of motion and posterior capsule tightness in patients with dominant or nondominant shoulder impingement. Measurements of posterior capsule tightness and external and internal rotation range of motion were made in 31 patients with shoulder impingement and in 33 controls without shoulder abnormality. Patients with impingement in the nondominant arm had increased posterior capsule tightness and decreased internal and external rotation range of motion compared with controls. Patients with impingement in their dominant arm had increased posterior capsule tightness and reduced internal rotation range of motion but no significant loss of external rotation range of motion compared with controls. Posterior capsule tightness in impingement patients showed a significant correlation with loss of internal rotation range of motion. Patients with shoulder impingement in their nondominant arm had a more global loss of range of motion compared with patients having impingement in their dominant arm. We believe we have described a valid clinical measurement for identifying posterior capsule tightness in patients with shoulder impingement.

The association of hip strength and flexibility with the incidence of adductor muscle strains in professional ice hockey players.

This prospective study was conducted to determine whether hip muscle strength and flexibility play a role in the incidence of adductor and hip flexor strains in National Hockey League ice hockey team players. Hip flexion, abduction, and adduction strength were measured in 81 players before two consecutive seasons. Thirty-four players were cut, traded, or sent to the minor league before the beginning of the season. Injury and individual exposure data were recorded for the remaining 47 players. Eight players experienced 11 adductor muscle strains, and there were 4 hip flexor strains. Preseason hip adduction strength was 18% lower in the players who subsequently sustained an adductor muscle strain compared with that of uninjured players. Adduction strength was 95% of abduction strength in the uninjured players but only 78% of abduction strength in the injured players. Preseason hip adductor flexibility was not different between players who sustained adductor muscle strains and those who did not. These results indicate that preseason hip strength testing of professional ice hockey players can identify players at risk of developing adductor muscle strains. A player was 17 times more likely to sustain an adductor muscle strain if his adductor strength was less than 80% of his abductor strength.

Reconstruction of the Coracoclavicular Ligaments with Tendon Grafts A Comparative Biomechanical Study

Background Numerous surgical techniques have been described to address injuries to the coracoclavicular ligaments. Purpose To compare the biomechanical properties of tendon graft reconstructions with those of the native coracoclavicular ligaments and various other repair methods. Study Design Controlled laboratory study. Methods Eleven fresh-frozen human cadaveric shoulders were tensile tested to failure to compare the biomechanical properties of the native coracoclavicular ligaments, coracoacromial ligament transfer, No. 5 Mersilene suture repair, 5-mm Mersilene tape repair, and tendon graft reconstructions with gracilis, semitendinosus, and long toe extensor tendons. Results Reconstructions with semitendinosus, gracilis, or long toe extensor tendon grafts were found to have superior initial biomechanical properties compared with coracoacromial ligament transfer; failure strengths were as strong as those of the native coracoclavicular ligaments. Failure of the tendon grafts occurred through the midsubstance of the tendon graft, not at the fixation site. Conclusions Tendon graft reconstruction may be an alternative to coracoacromial ligament transfer and may provide a permanent biologic reconstruction with superior initial biomechanical properties, including that of tensile strength. Clinical Relevance Use of tendon graft reconstruction may limit the need for postoperative immobilization and lead to an accelerated rehabilitation program.

The Role of Passive Muscle Stiffness in Symptoms of Exercise-Induced Muscle Damage

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.

The role of hip muscle function in the treatment of patellofemoral pain syndrome.

Background Previous literature has associated hip weakness with patellofemoral pain syndrome. Hypothesis Improvements in hip strength and flexibility are associated with a decrease in patellofemoral pain. Study Design Cohort study; Level of evidence, 2. Methods Thirty-five patients with patellofemoral pain syndrome, aged 33 ± 16 years (29 women, 6 men; 43 knees), were evaluated and placed on a 6-week treatment program. Hip flexion, abduction, and adduction strengths, Thomas and Ober test results, and visual analog scale scores for pain with activities of daily living as well as with exercise were documented on initial evaluation and again 6 weeks later. Treatment consisted of strength and flexibility exercises primarily focusing on the hip. Results Hip flexion strength improved by 35% ± 8.4% in 26 lower extremities treated successfully, compared with –1.8% ± 3.5% in 17 lower extremities with an unsuccessful outcome (P< .001). Before treatment, there were positive Ober test results in 39 of 43 lower extremities; positive Thomas test results were seen in 31 of 43 lower extremities. A successful outcome with a concurrent normalized Ober test result was seen in 83% (20/24) of lower extremities, and successful outcomes with normalized Thomas test results were seen in 80% (16/20) of lower extremities. A combination of improved hip flexion strength (> 20%) as well as normal Ober and Thomas test results was seen in 93% of successfully treated cases (14/15 lower extremities), compared with 0% success (0/5 lower extremities) if there was no change in hip flexion strength (< 20%) and if Ober and Thomas test results remained positive. Conclusions Improvements in hip flexion strength combined with increased iliotibial band and iliopsoas flexibility were associated with excellent results in patients with patellofemoral pain syndrome.

Risk Factors for Noncontact Ankle Sprains in High School Football Players The Role of Previous Ankle Sprains and Body Mass Index

Background In a previous study, we noted a possible connection between an athletes weight and risk of ankle sprain. Hypothesis A high body mass index and a history of a previous ankle sprain increase the risk of a subsequent noncontact sprain. Study Design Cohort study; Level of evidence, 2. Methods One hundred fifty-two athletes from 4 football teams were observed (2 varsity and 2 junior varsity). Two teams were observed for 3 seasons, and 2 teams were observed for 1 season. Before each season, body mass, height, history of previous ankle sprains, and ankle tape or brace use were recorded. Results There were 24 ankle sprains, of which 15 were noncontact inversion sprains (11 grade I, 3 grade II, 1 grade III; incidence, 1.08 per 1000 athlete-exposures). Injury incidence was higher in athletes with previous ankle injuries (2.60 vs 0.39; P< .001). Body mass index was also a risk factor (P< .05): injury incidence was 0.52 for players with a normal body mass index, 1.05 for players at risk of overweight, and 2.03 for overweight players. Injury incidence was 0.22 for normal-weight players with no previous ankle sprain compared with 4.27 for overweight players who had a previous sprain. Conclusion An overweight player who had a previous ankle sprain was 19 times more likely to sustain a noncontact ankle sprain than was a normal-weight player with no previous ankle sprain. Clinical Relevance Ankle sprain prevention strategies should be targeted at football players with a high body mass index and a history of previous ankle sprains.

The Effectiveness of a Preseason Exercise Program to Prevent Adductor Muscle Strains in Professional Ice Hockey Players

Background: Adductor strains are among the most common injuries in ice hockey. Hip adductor weakness has been identified as a strong risk factor. Hypothesis: An intervention program including muscle strengthening can reduce the incidence of adductor strains in professional ice hockey players. Study Design: Prospective risk factor prevention study. Methods: Thirty-three of 58 players from the same National Hockey League team were identified as “at risk” on the basis of preseason hip adductor strength and participated in an intervention program. The program consisted of 6 weeks of exercises aimed at functional strengthening of the adductor muscles. Injury and individual exposure data were recorded for all players. Results: There were 3 adductor strains in the 2 seasons subsequent to the intervention, compared with 11 in the previous 2 seasons (0.71 versus 3.2 per 1000 player-game exposures). All adductor strains were first-degree strains and occurred during games. Conclusions: A therapeutic intervention of strengthening the adductor muscle group appears to be an effective method for preventing adductor strains in professional ice hockey players.

Risk Factors for Noncontact Ankle Sprains in High School Athletes The Role of Hip Strength and Balance Ability

Background Ankle sprains are among the most common sports injuries. Hypothesis Poor balance as measured on a balance board and weakness in hip abduction strength are associated with an increased risk of noncontact ankle sprains in high school athletes. Study Design Cohort study; Level of evidence, 2. Methods One hundred sixty-nine high school athletes (101 male athletes, 68 female athletes) from football, mens basketball, mens soccer, womens gymnastics, womens basketball, and womens soccer were observed for 2 years. Balance in single-limb stance on an instrumented tilt board and hip flexion, abduction, and adduction strength (handheld dynamometer) were assessed in the preseason. Body mass, height, generalized ligamentous laxity, previous ankle sprains, and ankle tape or brace use were also documented. Results There were 20 noncontact inversion ankle sprains. Balance ability (P= .72), hip abduction strength (P= .66), hip adduction strength (P= .41), and hip flexion strength (P= .87) were not significant risk factors for ankle sprains. The incidence of grade II and grade III sprains was higher in athletes with a history of a previous ankle sprain (1.12 vs 0.26 per 1000 exposures, P< .05). A higher body mass index in male athletes was associated with increased risk (P< .05). The combination of a previous injury and being overweight further increased risk (P< .01). Conclusion Balance as measured on a balance board and hip strength were not significant indicators for noncontact ankle sprains. The apparent high injury risk associated with the combination of a history of a previous ankle sprain and being overweight in male athletes warrants further examination.

Correction of Posterior Shoulder Tightness Is Associated With Symptom Resolution in Patients With Internal Impingement

Background Glenohumeral internal rotation deficit (GIRD) and posterior shoulder tightness have been linked to internal impingement. Purpose To determine if improvements in GIRD and/or decreased posterior shoulder tightness are associated with a resolution of symptoms. Study Design Cohort study; Level of evidence, 3. Methods Passive internal rotation and external rotation (ER) range of motion (ROM) at 90° of shoulder abduction and posterior shoulder tightness (cross-chest adduction in side lying) were assessed in 22 patients with internal impingement (11 men, 11 women; age 41 ± 13 years). Treatment involved stretching and mobilization of the posterior shoulder. The Simple Shoulder Test (SST) was administered on initial evaluation and discharge. Changes in GIRD, ER ROM, and posterior shoulder tightness were compared between patients with complete resolution of symptoms versus patients with residual symptoms using independent t tests. Results Patients had significant GIRD (35°), loss of ER ROM (23°), and posterior shoulder tightness (35°) on initial evaluation (all P < .01). Physical therapy (7 ± 2 weeks; range, 3-12 weeks) improved GIRD (26° ± 14°; P < .01), ER ROM loss (14° ± 20°), and posterior shoulder tightness (27° ±19°). The SST improved from 5 ± 3 to 11 ± 1 (P < .01). A greater improvement in posterior shoulder tightness was seen in patients with complete resolution of symptoms (n = 12) compared with patients with residual symptoms (35° vs 18°; P < .05). Improvements in GIRD and ER ROM loss were not different between groups (GIRD, 25° vs 28°, P = .57; ER ROM, 14° vs 15°, P = .84). Conclusion Resolution of symptoms after physical therapy treatment for internal impingement was related to correction of posterior shoulder tightness but not correction of GIRD.

The Effectiveness of a Balance Training Intervention in Reducing the Incidence of Noncontact Ankle Sprains in High School Football Players

Background A high body mass index and previous ankle sprains have been shown to increase the risk of sustaining noncontact inversion ankle sprains in high school football players. Hypothesis Stability pad balance training reduces the incidence of noncontact inversion ankle sprains in football players with increased risk. Study Design Cohort study; Level of evidence, 2. Methods Height, body mass, history of previous ankle sprains, and current ankle brace/tape use were documented at the beginning of preseason training in 2 high school varsity football teams for 3 consecutive years (175 player-seasons). Players were categorized as minimal risk, low risk, moderate risk, and high risk based on the history of previous ankle sprain and body mass index. Players in the low-, moderate-, and high-risk groups (ie, any player with a high body mass index and/or a previous ankle sprain) were placed on a balance training intervention on a foam stability pad. Players balanced for 5 minutes on each leg, 5 days per week, for 4 weeks in preseason and twice per week during the season. Postintervention injury incidence was compared with preintervention incidence (107 players-seasons) for players with increased risk. Results Injury incidence for players with increased risk was 2.2 injuries per 1000 exposures (95% confidence interval, 1.1-3.8) before the intervention and 0.5 (95% confidence interval, 0.2-1.3) after the intervention (P < .01). This represents a 77% reduction in injury incidence (95% confidence interval, 31%-92%). Conclusion The increased risk of a noncontact inversion ankle sprain associated with a high body mass index and a previous ankle sprain was eliminated by the balance training intervention.