The American Journal of Sports Medicine

Patients with osteoarthritis of the knee are at risk for poorer outcomes after arthroscopic meniscectomy. Intra-articular corticosteroid injections have been shown to be efficacious both in patients with osteoarthritis and postarthroscopy patients.

A postoperative, intra-articular methylprednisolone and lidocaine injection in patients with chondromalacia undergoing meniscectomy will improve patient-rated pain and function compared with control patients.

Randomized, controlled trial; Level of evidence, 1.

A total of 58 patients (59 knees) were randomized in a double-blinded fashion to receive either saline plus lidocaine (saline) or methylprednisolone plus lidocaine (steroid) after arthroscopic meniscectomy in which chondromalacia (modified Outerbridge grade 2 or higher) was confirmed. Preoperatively and at follow-up—6 weeks and 6, 9, and 12 months—patients underwent an examination and completed a subjective functioning survey. Scores were calculated using several validated scoring systems including the Lysholm, International Knee Documentation Committee (IKDC), and Short Form–12 (SF-12).

No statistically significant differences were observed between the saline (n = 30) and steroid (n = 29) groups in their demographics and preoperative scores. At 6 weeks, the steroid group had higher scores than the saline group on multiple scales, including the IKDC. No differences in outcome scores existed at later time points. At 12 months, 86% of the steroid and 69% of the saline group were completely or mostly satisfied with the procedure (P = .01). In the saline group, 4 patients required reinjection and 2 underwent joint replacements within 12 months, while the steroid group had 3 reinjections and 2 meniscus transplants.

The addition of a postoperative corticosteroid injection resulted in improved pain and function at an early time point; however, it provided no lasting difference compared with only local anesthetic injection.

Patellofemoral lesions represent a very troublesome condition to treat for orthopaedic surgeons; however, second-generation autologous chondrocyte implantation (ACI) seems to offer an interesting treatment option with satisfactory results at short-term follow-up.

Hyaluronan-based scaffold seeded with autologous chondrocytes is a viable treatment for the damaged articular surface of the patellofemoral joint.

Case series; Level of evidence, 4.

Among a group of 38 patients treated for full-thickness patellofemoral chondral lesions with second-generation ACI, we investigated 34 who were available for final follow-up at 5 years. These 34 had chondral lesions with a mean size of 4.45 cm². Twenty-one lesions were located on the patella, 9 on the trochlea, and 4 patients had multiple lesions: 3 had patellar and trochlear lesions, and 1 had patellar and lateral femoral condyle lesions. Twenty-six lesions (76.47%) were classified as International Cartilage Repair Society (ICRS) grade IV A or B, 5 lesions (14.70%) were grade IIIC, and 3 (8.82%) were lesions secondary to osteochondritis dissecans (OCD). Results were evaluated using the International Knee Documentation Committee (IKDC) 2000 subjective and objective scores, EuroQol (EQ) visual analog scale (VAS), and Tegner scores at 2 and 5 years. Eight patients had second-look arthroscopy and biopsies.

All the scores used demonstrated a statistically significant improvement (P < .0005) at 2 and 5 years’ follow-up. Objective preoperative data improved from 8 of 34 (23.52%) normal or nearly normal knees to 32 of 34 (94.12%) at 2 years and 31 of 34 (91.17%) at 5 years after transplantation. Mean subjective scores improved from 46.09 points preoperatively to 77.06 points 2 years after implantation and 70.39 at 5 years. The Tegner score improved from 2.56 to 4.94 and 4.68, and the EQ VAS improved from 56.76 to 81.47 and 78.23 at 2 and 5 years’ follow-up, respectively. A significant decline of IKDC subjective and Tegner scores was found in patients with multiple and patellar lesions from 2 to 5 years’ follow-up. Second-look arthroscopies in 8 cases revealed the repaired surface to be nearly normal with biopsy samples characterized as hyaline-like in appearance.

Hyaluronan-based scaffold seeded with autologous chondrocytes can be a viable treatment for patellofemoral chondral lesions.

Although labrum lesions in patients with chronic anterior shoulder instability may not only involve detachment of the anteroinferior labrum but a lesion of the superior glenoid labrum as well, no studies have compared the clinical outcome between patients with a lesion of the anteroinferior labrum and patients with a combined lesion of the anterior and superior labrum after arthroscopic shoulder stabilization.

Arthroscopic repair of a combined lesion of the anterior and superior labrum may have inferior clinical outcome to repair of an anterior lesion only in patients with anterior shoulder instability.

Cohort study; Level of evidence, 2.

Sixty-three patients operated on for anterior shoulder instability between April 2002 and June 2006 were included in this study. Patients with bone deficiency were excluded. Fixation of the detached labrum was performed using suture anchors. Thirty-eight patients had a lesion of the anterior labrum (group A), and 25 had a combined lesion of the anterior and superior labrum (group B). Patients were evaluated after a 2-year minimum follow-up with Constant and Rowe scores. Failure was defined as a redislocation or a subluxation episode.

Patients in group B experienced a significantly higher number of dislocations preoperatively (P < .05). However, there was no difference between the 2 groups regarding the failure rate postoperatively. One patient from each group had a failed result. A mean loss of 5° and 8° of external rotation at 90° of abduction was noted in patients in groups A and B, respectively (P = .113). The Constant score was 94 in group A and 93 in group B (P = .435). The Rowe score was 91 in group A and 90 in group B (P = .338).

There are no differences in shoulder stability and function in patients with anterior shoulder instability and a lesion of the anteroinferior labrum and patients with an extended lesion of the anterior and superior labrum after arthroscopic shoulder stabilization.

Delayed onset of vastus medialis obliquus activity has been described in patellofemoral pain patients. No prospective study investigating the development of patellofemoral pain has tested the onset timing of electromyographic activity of the vastus medialis obliquus and vastus lateralis muscles during a functional task.

Before the development of patellofemoral pain, subjects demonstrate an altered firing order of the vastus medialis obliquus and vastus lateralis muscles compared with healthy subjects during a functional task.

Cohort study; Level of evidence, 2.

The onset of vastus medialis obliquus and vastus lateralis activity was measured with surface electromyography during a functional task (rocking back on the heels) in 79 healthy subjects subsequently submitted to a 6-week strenuous basic military training. Afterward, these subjects were reassessed.

Thirty-two percent of the recruits developed patellofemoral pain during training. Patellofemoral pain subjects demonstrated a significant delay of onset of vastus medialis obliquus electromyographic activity compared with the healthy controls (P = .023), even before basic military training. In healthy subjects, no significant differences in electromyographic activity onset of the vastus medialis obliquus compared with the vastus lateralis could be identified before and after basic military training. A significant (P < .001) delay could be demonstrated in the patellofemoral pain group after basic military training. A binary logistic regression could be constructed wherein the onset of the electromyographic activity of the vastus medialis obliquus and vastus lateralis was withheld in the model. The most optimal cutoff value, which is based on the receiver operating characteristic curve, is a timing difference of −0.67 milliseconds (vastus medialis obliquus – vastus lateralis). The area under the receiver operating characteristic curve is considered as fair (0.68).

Delayed onset of electromyographic activity of the vastus medialis obliquus–vastus lateralis is one of the contributing risk factors to the development of patellofemoral pain.

The reported failure rate of arthroscopic rotator cuff repair varies widely. The influence of repair technique on failure rates and functional outcomes after arthroscopic cuff repair remains controversial.

To determine the functional outcome of arthroscopic knotless fixation using the Opus AutoCuff device for rotator cuff repair and to compare our results with those reported in the literature.

Case series; Level of evidence, 4.

Fifty-six consecutive patients underwent arthroscopic rotator cuff repair using an Opus AutoCuff device (Arthrocare, Sunnydale, California) with greater than 2 years’ follow-up. Subjective and objective clinical examinations were performed to include the University of California at Los Angeles (UCLA) shoulder score, the American Shoulder and Elbow Surgeons (ASES) rating scale, the visual analog scale (VAS), and the Tegner Activity Level scale.

Forty-eight patients were evaluated at a mean follow-up of 26 months (range, 24–35 months). The mean UCLA shoulder score was 33.1 of 35 (SD, 2.89) possible points, and the mean ASES rating scale was 94.2 of 100 (SD, 7.76) compared with a mean preoperative score of 65.7 (P < .001). Postoperative UCLA shoulder scores had 42 of 45 (93.3%) patients with good and excellent results. The mean preoperative ASES pain score was 1.3 (SD, 1.0), and the mean postoperative score was 4.4 (SD, 1.0) (P < .001). The Tegner Activity Level scores demonstrated restoration of function to preinjury status. There were 3 failures (6.3%), 2 by anchor failure (1 with specific trauma), and 1 by rotator cuff retear, all requiring revision surgery.

Arthroscopic knotless suture fixation with the Opus AutoCuff device results in good to excellent results similar to those reported in the literature with conventional suture anchors.

Meniscal repair is performed in an attempt to prevent posttraumatic arthritis resulting from meniscal dysfunction after meniscal tears. The socioeconomic implications of premature arthritis are significant in the young patient population. Investigations and techniques focusing on meniscus preservation and healing are now at the forefront of orthopaedic sports medicine.

Concomitant meniscal repair with anterior cruciate ligament reconstruction is a durable and successful procedure at 2-year follow-up.

Case series; Level of evidence, 4.

All unilateral primary anterior cruciate ligament reconstructions entered in 2002 in a cohort who had meniscal repair at the time of anterior cruciate ligament reconstruction were evaluated. Validated patient-oriented outcome instruments were completed preoperatively and then again at the 2-year postoperative time point. Reoperation after the index procedure was also documented and confirmed by operative reports.

A total of 437 unilateral primary anterior cruciate ligament reconstructions were performed with 82 concomitant meniscal repairs (54 medial, 28 lateral) in 80 patients during the study period. Patient follow-up was obtained on 94% (77 of 82) of the meniscal repairs, allowing confirmation of meniscal repair success (defined as no repeat arthroscopic procedure) or failure. The overall success rate for meniscal repairs was 96% (74 of 77 patients) at 2-year follow-up.

Meniscal repair is a successful procedure in conjunction with anterior cruciate ligament reconstruction. When confronted with a “repairable” meniscal tear at the time of anterior cruciate ligament reconstruction, orthopaedic surgeons can expect an estimated >90% clinical success rate at 2-year follow-up using a variety of methods as shown in our study.

In cases of multiple ligament injury or severe medial collateral ligament (MCL) lesion, nonoperative treatment of the MCL lesion may lead to chronic valgus instability or rotatory instability.

In a retrospective case series after isolated and combined MCL reconstructions using a novel MCL reconstruction technique that addresses both the MCL and the posteromedial corner, an acceptable clinical outcome is expected 2 years after MCL reconstruction.

Case series; Level of evidence, 4.

From July 2002 to December 2005, 61 patients with grade 3 or 4 medial instability were treated with MCL reconstruction. Median age was 33 years (range, 14–62). Thirteen underwent isolated MCL reconstructions, 34 had combined MCL and anterior cruciate ligament (ACL) reconstruction, and 14 had multiple ligament reconstructions. All patients had reconstruction of the medial collateral and the posteromedial complex using ipsilateral semitendinosus autografts. Fifty patients were available for follow-up more than 24 months postoperatively and were examined by an independent observer using objective International Knee Documentation Committee (IKDC) measures and subjective Knee Injury and Osteoarthritis Outcome Score (KOOS).

At follow-up, medial stability according to the IKDC score showed 98% normal or nearly normal (grade A or B), and for overall IKDC score, patients improved from 5% with grade A or B preoperatively to 74% with grade A or B at follow-up. There were 91% who were satisfied or very satisfied with the result; 88% would go through surgery again. The KOOS improved primarily for sports and quality of life subscales with approximately 10-point improvements.

Acceptable clinical results with the MCL reconstruction technique were achieved in patients suffering from chronic valgus instability.

The medial collateral ligament is a broad ligament that functions as the primary stabilizer against valgus knee stress, particularly at 30° of flexion.

A double-bundle reconstruction technique that better restores the native medial collateral ligament anatomy will restore valgus and external rotation stability to a medial collateral ligament–deficient knee.

Controlled laboratory study.

Seven fresh-frozen cadaveric knees were studied. A surgical navigation system was used to determine valgus opening and external rotation at 0° and 30° with a 9.8-N·m valgus stress applied to the tibia graft isometry at multiple points on the tibia and femur. Intact and disrupted medial collateral ligament knees were used as controls. Four repair techniques were tested: Bosworth, modified Bosworth, anatomical single bundle, and anatomical double bundle.

Complete sectioning of the medial collateral ligament resulted in an increase in valgus opening of 5° at 0° and 7.7° at 30°. External rotation increased 4.6° at 0° and 9.7° at 30°. Single-bundle techniques (Bosworth, anatomical single bundle) did not restore valgus laxity at 0° or 30°; the anatomical single bundle did not restore external rotation at 0°. Double-bundle techniques (modified Bosworth, anatomical double bundle) restored valgus laxity and external rotation to the native knee conditions at 0° and 30°. At 30°, the modified Bosworth was 0.3° tighter and the anatomical double bundle 0.2° tighter than was the intact knee. The center of the medial collateral ligament origin on the femur to the proximal insertion of the superficial medial collateral ligament resulted in the most isometric graft position.

Medial collateral ligament reconstruction configurations that use a double-bundle reconstruction better resist valgus and external rotations in response to valgus stress than do single-bundle techniques.

Although the medial collateral ligament often heals without surgical intervention, surgical reconstruction is occasionally necessary in grade III medial collateral ligament and combined ligamentous injuries to the knee. Double-bundle reconstruction of the medial collateral ligament better resists valgus forces across the knee and may allow for better surgical outcome after medial collateral ligament reconstruction.

The preservation of meniscal tissue is important to protect joint surfaces.

We have an aggressive approach to meniscal repair, including repairing tears other than those classically suited to repair. Here we present the medium- to long-term outcome of meniscal repair (inside-out) in elite athletes.

Case series; Level of evidence, 4.

Forty-two elite athletes underwent 45 meniscal repairs. All repairs were performed using an arthroscopically assisted inside-out technique. Eighty-three percent of these athletes had ACL reconstruction at the same time. Patients returned a completed questionnaire (including Lysholm and International Knee Documentation Committee [IKDC] scores). Mean follow-up was 8.5 years. Failure was defined by patients developing symptoms of joint line pain and/or locking or swelling requiring repeat arthroscopy and partial meniscectomy.

The average Lysholm and subjective IKDC scores were 89.6 and 85.4, respectively. Eighty-one percent of patients returned to their main sport and most to a similar level at a mean time of 10.4 months after repair, reflecting the high level of ACL reconstruction in this group. We identified 11 definite failures, 10 medial and 1 lateral meniscus, that required excision; this represents a 24% failure rate. We identified 1 further patient who had possible failed repairs, giving a worst-case failure rate of 26.7% at a mean of 42 months after surgery. However, 7 of these failures were associated with a further injury. Therefore, the atraumatic failure rate was 11%. Age and size and location of the tears were not associated with a higher failure rate. Medial meniscal repairs were significantly more likely to fail than lateral meniscal repairs, with a failure rate of 36.4% and 5.6%, respectively (P < .05).

Meniscal repair and healing are possible, and most elite athletes can return to their preinjury level of activity.

Standard nonoperative therapy for acute muscle strains usually involves short-term rest, ice, and nonsteroidal anti-inflammatory medications, but there is no clear consensus on how to accelerate recovery.

Local delivery of platelet-rich plasma to injured muscles hastens recovery of function.

Controlled laboratory study.

In vivo, the tibialis anterior muscles of anesthetized Sprague-Dawley rats were injured by a single (large strain) lengthening contraction or multiple (small strain) lengthening contractions, both of which resulted in a significant injury. The tibialis anterior either was injected with platelet-rich plasma, was injected with platelet-poor plasma as a sham treatment, or received no treatment.

Both injury protocols yielded a similar loss of force. The platelet-rich plasma only had a beneficial effect at 1 time point after the single contraction injury protocol. However, platelet-rich plasma had a beneficial effect at 2 time points after the multiple contraction injury protocol and resulted in a faster recovery time to full contractile function. The sham injections had no effect compared with no treatment.

Local delivery of platelet-rich plasma can shorten recovery time after a muscle strain injury in a small-animal model. Recovery of muscle from the high-repetition protocol has already been shown to require myogenesis, whereas recovery from a single strain does not. This difference in mechanism of recovery may explain why platelet-rich plasma was more effective in the high-repetition protocol, because platelet-rich plasma is rich in growth factors that can stimulate myogenesis.

Because autologous blood products are safe, platelet-rich plasma may be a useful product in clinical treatment of muscle injuries.

Human circus arts are gaining increasing popularity as a physical activity with more than 500 companies and 200 schools. The only injury data that currently exist are a few case reports and 1 survey.

To describe injury patterns and injury rates among Cirque du Soleil artists between 2002 and 2006.

Descriptive epidemiology study.

The authors defined an injury as any work-related condition recorded in an electronic injury database that required a visit to the show therapist. Analyses for treatments, missed performances, and injury rates (per 1000 artist performances) were based on a subset of data that contained appropriate denominator (exposure) information (began in 2004).

There were 1376 artists who sustained a total of the 18 336 show- or training-related injuries. The pattern of injuries was generally similar across sex and performance versus training. Most injuries were minor. Of the 6701 injuries with exposure data, 80% required ≤7 treatments and resulted in ≤1 completely missed performance. The overall show injury rate was 9.7 (95% confidence interval, 9.4–10.0; for context, published National Collegiate Athletic Association women’s gymnastics rate was 15.2 injuries per 1000 athlete-exposures). The rate for injuries resulting in more than 15 missed performances for acrobats (highest risk group) was 0.74 (95% confidence interval, 0.65–0.83), which is much lower than the corresponding estimated National Collegiate Athletic Association women’s gymnastics rate.

Most injuries in circus performers are minor, and rates of more serious injuries are lower than for many National Collegiate Athletic Association sports.

Treatment of tibial stress fractures in elite dancers is centered on rest and activity modification. Surgical intervention in refractory cases has important implications affecting the dancers’ careers.

Refractory tibial stress fractures in dancers can be treated successfully with drilling and bone grafting or intramedullary nailing.

Case series; Level of evidence, 4.

Between 1992 and 2006, 1757 dancers were evaluated at a dance medicine clinic; 24 dancers (1.4%) had 31 tibial stress fractures. Of that subset, 7 (29.2%) elite dancers with 8 tibial stress fractures were treated operatively with either intramedullary nailing or drilling and bone grafting. Six of the patients were followed up closely until they were able to return to dance. One patient was available only for follow-up phone interview. Data concerning their preoperative treatment regimens, operative procedures, clinical union, radiographic union, and time until return to dance were recorded and analyzed.

The mean age of the surgical patients at the time of stress fracture was 22.6 years. The mean duration of preoperative symptoms before surgical intervention was 25.8 months. Four of the dancers were male and 3 were female. All had failed nonoperative treatment regimens. Five patients (5 tibias) underwent drilling and bone grafting of the lesion, and 2 patients (3 tibias) with completed fractures or multiple refractory stress fractures underwent intramedullary nailing. Clinical union was achieved at a mean of 6 weeks and radiographic union at 5.1 months. Return to full dance activity was at an average of 6.5 months postoperatively.

Surgical intervention for tibial stress fractures in dancers who have not responded to nonoperative management allowed for resolution of symptoms and return to dancing with minimal morbidity.

The injury rate in soccer is high, and studies have shown that the injury rate among players aged 16 years or older approaches that of adult players. However, little is known about the injury risk among the youngest players, that is, players between 6 and 12 years.

To examine the risk of injuries in children 6 to 16 years old playing organized soccer.

Descriptive epidemiological study.

Injuries were recorded prospectively throughout 1 season among 121 soccer teams (1879 players, aged 6–16 years) from 2 communities in the southeastern part of Norway.

A total of 159 players sustained 200 injuries, corresponding to an overall injury incidence of 2.2 per 1000 playing hours (95% confidence interval, 1.8–2.6) among boys and 2.0 injuries per 1000 hours (95% confidence interval, 1.4–2.5) among girls. The overall injury incidence was significantly higher (relative risk, 1.7; 95% confidence interval, 1.3–2.2) among older players (13–16 years; 2.6 injuries per 1000 hours, 95% confidence interval, 2.2–3.0) than among younger players (6–12 years; 1.6 injuries per 1000 hours, 95% confidence interval, 1.2–1.9). The injuries recorded in the youngest group were few and mainly mild.

The injury risk among young players (6–12 years) playing organized 5- or 7-a-side soccer is low, lower than that of adolescents and much lower than at the elite level. Soccer is a safe sport for children.

Various shoulder outcome instruments have been used despite lack of information on their measurement properties; reliability, responsiveness, and validity; and correlation with health-related quality of life.

Most shoulder outcome instruments have poor correlation with Short Form−36, a general measure of health-related quality of life, and with each other.

Cohort study (diagnosis); Level of evidence, 2.

A consecutive group of 285 patients who had undergone shoulder surgery completed several shoulder outcome instruments—Short Form−36; University of California, Los Angeles shoulder score; American Shoulder and Elbow Surgeons shoulder evaluation form; Constant score; Simple Shoulder Test; Western Ontario Shoulder Instability Index; and the rating sheet for Bankart repair (Rowe score)—preoperatively and at 3, 6, 9, and 12 months postoperatively. Internal consistency, standardized response mean, effect size, and Pearson correlation were used to evaluate reliability, responsiveness, and validity.

The American Shoulder and Elbow Surgeons form, Simple Shoulder Test, and Western Ontario Shoulder Instability Index displayed good internal consistency. The University of California, Los Angeles shoulder score and American Shoulder and Elbow Surgeons form exhibited good responsiveness, whereas Short Form−36 showed the least responsiveness. Pearson correlation coefficients between the shoulder outcome instruments and Short Form−36 were less than excellent (r < .60). Pearson correlation coefficients between the outcome instruments were generally low except for the Constant score and University of California, Los Angeles shoulder score (r = .673, P < .01).

There was no single shoulder outcome instrument that was superior to the others in terms of the measurement properties. Most of the tested shoulder outcome instruments did not reflect health-related quality of life well and poorly correlated with each other. This meant that the comparison of a given surgical result with different outcome instruments might be of little practical utility. Further prospective and serial studies should be conducted to develop better shoulder outcome instruments that have significant reliability, responsiveness, validity, and correlation with health-related quality of life. A careful combination of outcome instruments might be necessary to compensate the current evaluation systems.

It has been speculated that the hormonal cycle may be correlated with higher incidence of ACL injury in female athletes, but results have been very contradictory.

Knee joint loads are influenced by knee joint laxity (KJL) during the menstrual cycle.

Controlled laboratory study.

Serum samples and KJL were assessed at the follicular, ovulation, and luteal phases in 26 women. Knee joint mechanics (angle, moment, and impulse) were measured and compared at the same intervals. Each of the 26 subjects had a value for knee laxity at each of the 3 phases of their cycle, and these were ordered and designated low, medium, and high for that subject. Knee joint mechanics were then compared between low, medium, and high laxity.

No significant differences in knee joint mechanics were found across the menstrual cycle (no phase effect). However, an increase in KJL was associated with higher knee joint loads during movement (laxity effect). A 1.3-mm increase in KJL resulted in an increase of approximately 30% in adduction impulse in a cutting maneuver, an increase of approximately 20% in knee adduction moment, and a 20% to 45% increase in external rotation loads during a jumping and stopping task (P < .05).

Changes in KJL during the menstrual cycle do change knee joint loading during movements.

Our findings will be beneficial for researchers in the development of more effective ACL injury prevention programs.

Commonly performed arthroscopic rotator interval closure techniques that imbricate the rotator interval in a superior-inferior direction have been unable to reproduce the stabilizing effects of an open medial-lateral rotator interval imbrication.

The medial-lateral rotator interval closure will allow less inferior and posterior glenohumeral translation than the superior-inferior rotator interval closure, and the medial-lateral rotator interval closure will result in less loss of external rotation than the superior-inferior closure.

Controlled laboratory study.

Eight match-paired cadaveric shoulders were stretched to 10% beyond the maximum range of motion in 0° and 60° of glenohumeral abduction to create a multidirectional instability model. Shoulders were then repaired using a superior-inferior rotator interval closure or an arthroscopic medial-lateral rotator interval closure with an anchor in the humeral head. Rotational range of motion, glenohumeral translation, and humeral head apex position were measured for intact, stretched, and repaired conditions in both 0° and 60° of glenohumeral abduction.

In 0° of abduction, after both rotator interval closure techniques, external rotation decreased significantly (by 4.4%; P < .05) relative to the stretched state and was restored to the intact state. In 60° of abduction, only the medial-lateral rotator interval closure restored range of motion to the intact state. In 60° of abduction, the medial-lateral rotator interval closure was more effective in reducing posterior translation than was the superior-inferior closure (P = .03).

The medial-lateral rotator interval closure restored range of motion to the intact state better than the superior-inferior closure. Compared with the superior-inferior rotator interval closure, the medial-lateral closure significantly decreased posterior translation with the shoulder in abduction and external rotation.

Arthroscopic medial-lateral rotator interval closure with a suture anchor in the humeral head can be considered in the surgical treatment of patients with multidirectional instability, especially those with a component of posterior instability, without concern for excessive loss of range of motion.

Limited research in cricket bowlers and baseball pitchers has shown a correlation between workload and injury risk.

Acute high bowling workload in cricket leads to increased risk of bowling injury in future matches.

Cohort study (prognosis); Level of evidence, 2.

One hundred twenty-nine pace (fast) bowlers who bowled in 2715 player matches over a period of 10 seasons were followed to compare overs bowled in each match and injury risk subsequent to the match.

Bowlers who bowled more than 50 overs in a match had an injury incidence in the next 21 days of 3.37 injuries per 1000 overs bowled, a significantly increased risk compared with those bowlers who bowled less than 50 overs (relative risk [RR], 1.77; 95% confidence interval [CI]: 1.05–2.98). Bowlers who bowled more than 30 overs in the second inning of a match had a significantly increased injury risk per over bowled in the next 28 days (RR, 2.42; 95% CI: 1.38–4.26). Time periods of less than 21 days or more than 28 days after the match in question did not yield significant differences in injury risk per over bowled between high and low workload bowlers.

High acute workload in cricket fast bowlers may lead to a somewhat delayed increased risk of injury up to 3 to 4 weeks after the acute overload, possibly via a mechanism of damaging immature (repair) tissue.

Cricket fast bowling and possibly baseball pitching workloads require scrutiny not just for acute injuries but also for injury prevention in the subsequent month.

Junior rowers have competed internationally for over 4 decades, and there are no epidemiological data available on traumatic and overuse injury in this population.

To define the types of musculoskeletal problems present in international elite-level junior rowers and to determine whether gender, physical stature, rowing discipline, and training programs affect the incidence of reported injuries.

Descriptive epidemiology study.

Injury data were obtained from a total of 398 rowers (42% female, 58% male) who completed a 4-page questionnaire on injury incidence while participating at the Junior World Rowing Championships in Beijing, People’s Republic of China, in August 2007.

Overall, 290 (73.8%) reported injuries involved overuse, and 103 (26.2%) were related to a single traumatic event. Female rowers were injured more frequently than male rowers (110.2 vs 90.5 injuries per 100 rowers). In both genders, the most common injury site was the low back followed by the knee and the forearm/wrist. The severity of reported injuries was incidental in 65.1%, minor in 21.4%, moderate in 10.4%, and major in 3.1% of cases. The rowers with traumatic injuries had less rowing experience than the uninjured rowers (median [C] ± interquartile range [Q] = 3 ± 3 years vs 4 ± 3 years; P = .043, Mann-Whitney test). Sweep rowers who changed rowing side during the current season had significantly more acute-onset low back injuries (P = .012, χ² test) than those who did not change rowing side during the same period. The incidence of traumatic injuries was significantly lower in rowers who regularly performed more than 10 minutes of posttraining stretching (P = .030, χ² test). Athletes who ran more than once a week had more overuse knee injuries than those who ran once or less per week (P = .033, χ² test).

Elite junior rowers attending the World Rowing Championships reported predominantly overuse injuries of low severity during the current rowing season. Low back injuries were the most frequent complaint of elite-level junior rowers.

Ankle foot orthoses are used for postoperative treatment of Achilles tendon ruptures and decrease calf muscle electromyography activity during walking.

Achilles tendon load decreases with increased restriction of dorsiflexion and is associated with decreased triceps surae activity.

Controlled laboratory study.

In 8 subjects, the maximum force and rate of force development in the Achilles tendon were measured with an optic fiber technique, and the activity of the gastrocnemius, soleus, and tibialis anterior muscles was recorded using electromyography. Trial conditions were walking barefoot and wearing an ankle-foot orthoses set in 3 different positions: (1) locked at 20° of plantar flexion and with free plantar flexion but restricted dorsiflexion to (2) 10° plantar flexion and (3) 10° dorsiflexion, respectively. The design of the ankle foot orthoses did not provide heel support when fixed in a plantarflexed position.

Maximum Achilles tendon force was highest at the ankle-foot orthoses setting of 20° plantar flexion (3.1 times body weight) and decreased to 2.1 times body weight during barefoot walking (P < .01). The rate of Achilles tendon force showed an increasing trend with less-restricted dorsiflexion. Soleus activity was 52% of mean barefoot walking activity at 3 20° plantar flexion (P < .001) and then increased as dorsiflexion was less restricted.

Weightbearing in ankle-foot orthoses when dorsiflexion is restricted beyond neutral may result in increased forces in the Achilles tendon compared with barefoot walking, despite reduced electromyography activity in the triceps surae and decreased rate of force development.

If patients bear full weight in an ankle-foot orthoses locked at 20° plantar flexion without heel support, the maximum force in the tendon may exceed that encountered during barefoot walking.

Previous imaging studies have shown that degenerative disk disease is more common in the competitive female gymnast than in asymptomatic nonathletic people of the same age training to any degree. However, results of exposure-discordant monozygotic and classic twin studies suggest that physical loading specific to occupation and sport has a relatively minor role in disk degeneration, beyond that of upright postures and routine activities of daily living.

Intensive, regular, and prolonged dancing causes strain on the lumbar spine and can trigger or accelerate the development of degenerative diskopathy.

Cross-sectional study; Level of evidence, 3.

Forty volunteer female dancers (20 ballet and 20 flamenco) aged between 18 and 31 years (mean = 24.2) underwent magnetic resonance imaging of the lumbar spine. They were compared against a control group of 20 women of the same age. A descriptive analysis was done, and the 2 groups were compared by contingency table analysis using the Pearson chi-square test complemented by an analysis of residuals.

Nine of the 20 women (45%) in the control group had disk degeneration compared with 13 of the 40 (32.5%) women in the dancer group, with a chi-square of 0.897 (not significant). There were 12 degenerated disks of the 100 explored (12%) in the control group compared with 21 of the 200 explored (10.5%) in the dancer group (chi-square = 0.153; not significant).

Dancing cannot be considered a risk factor for lumbar disk degeneration in women.

The present study indicates that dancing has no negative effect on the development of degenerative diskopathy.

Treatment of midportion Achilles tendinopathy is hampered by limited knowledge of the pathophysiology.

Chondrogenic differentiation of tendon cells might take place in midportion Achilles tendinopathy and could be used as a target for drug treatment. An in vitro model for chondrogenic differentiation would be useful to evaluate existing and future treatment opportunities.

Descriptive and controlled laboratory study.

Perioperatively harvested tissue from human midportion Achilles tendinotic lesions and healthy Achilles tendons was analyzed by microscopy and real-time reverse transcription polymerase chain reaction. In vitro chondrogenic differentiation of tendon explants was induced using transforming-growth-factor beta. This model was modulated by removing the chondrogenic stimulus or adding triamcinolone or platelet-rich plasma.

Midportion Achilles tendinotic lesions had increased glycosaminoglycan staining and more rounded cell nuclei. Chondrogenic markers (sex-determining region Y)–box9, aggrecan, collagen 2, and RUNT-related transcription factor 2 were upregulated, but collagen 10 was not. Nondegenerative tendon explants cultured on chondrogenic medium had higher expression of aggrecan, collagen 2, and collagen 10 but not (sex-determining region Y)–box9 and RUNT-related transcription factor 2. Removing the chondrogenic stimulus decreased expression of aggrecan, collagen 2, and collagen 10. Both triamcinolone and platelet-rich plasma influenced the chondrogenic gene expression pattern in the in vitro model.

Chondrogenic differentiation is present in midportion Achilles tendinopathy. An in vitro model to study this chondrogenic differentiation was developed.

This model can be used to investigate chondrogenic differentiation as a possible target for drug treatment, contributing to the development of more successful mechanism-based treatment opportunities.