The American Journal of Sports Medicine

Verdonk R, Verdonk P, Huysse W, Forsyth R, Heinrichs E-L. Tissue ingrowth after implantation of a novel, biodegradable polyurethane scaffold for treatment of partial meniscal lesions. Am J Sports Med. 2011;39(4):774-782. (Original DOI:10.1177/0363546511398040)

In the above article, there is an error on page 775, introduction section, in the penultimate paragraph of the first column. The sentence reads “Therefore, the approximately 20-year degradation time for the collagen scaffold may be too short.”

The corrected sentence should read “Therefore, the approximately 2-year degradation time for the collagen scaffold may be too short.”

Background: A double-network (DN) gel, which was composed of poly-(2-acrylamido-2-methylpropanesulfonic acid) and poly-(N,N′-dimetyl acrylamide) (PAMPS/PDMAAm), has the potential to induce chondrogenesis both in vitro and in vivo.

Purpose: To establish the efficacy of a therapeutic strategy for an articular cartilage defect using a DN gel.

Study Design: Controlled laboratory study.

Methods: A 4.3-mm-diameter osteochondral defect was created in rabbit trochlea. A DN gel plug was implanted into the defect of the right knee so that a defect 2 mm in depth remained after surgery. An untreated defect of the left knee provided control data. The osteochondral defects created were examined by histological and immunohistochemical evaluations, surface assessment using confocal laser scanning microscopy, and real-time polymerase chain reaction (PCR) analysis at 4 and 12 weeks. Samples were quantitatively evaluated with 2 scoring systems reported by Wayne et al and O’Driscoll et al.

Results: The DN gel–implanted defect was filled with a sufficient volume of the hyaline cartilage tissue rich in proteoglycan and type 2 collagen. Quantitative evaluation using the grading scales revealed a significantly higher score in the DN gel–implanted defects compared with the untreated control at each period (P < .0001). The mean relative values of type 2 collagen mRNAs in the regenerated tissue were obviously higher in the DN gel–implanted defect than in the untreated control at each period. The mean surface roughness of the untreated control was significantly higher than the normal cartilage at 12 weeks (P = .0106), while there was no statistical difference between the DN gel–implanted and normal knees.

Conclusion: This study using the mature rabbit femoral trochlea osteochondral defect model demonstrated that DN gel implantation is an effective treatment to induce cartilage regeneration in vivo without any cultured cells or mammalian-derived scaffolds.

Clinical Relevance: This study has prompted us to develop a potential innovative strategy to repair cartilage lesions in the field of joint surgery.

Background: There are currently several approaches being pursued to treat focal defects of articular cartilage, each having specific advantages or challenges. A single-stage procedure that uses autologous cartilage fragments, Cartilage Autograft Implantation System (CAIS), is being evaluated in patients and may offer a clinically effective option.

Purpose: To establish the safety of CAIS and to test whether CAIS improves quality of life by using standardized outcomes assessment tools.

Study Design: Randomized controlled trial; Level of evidence, 2.

Methods: Patients (n = 29) were randomized (1:2) with the intent to treat with either a control (microfracture [MFX]) or an experimental (CAIS) procedure. Patients were followed at predetermined time points for 2 years using several standardized outcomes assessment tools (SF-36, International Knee Documentation Committee [IKDC], Knee injury and Osteoarthritis Outcome Score [KOOS]). Magnetic resonance imaging was performed at baseline, 3 weeks, and 6, 12, and 24 months.

Results: Lesion size and International Cartilage Repair Society (ICRS) grade were similar in both groups. General outcome measures (eg, physical component score of the SF-36) indicated an overall improvement in both groups, and no differences in the number of adverse effects were noted in comparisons between the CAIS and MFX groups. The IKDC score of the CAIS group was significantly higher (73.9 ± 14.72 at 12 months and 82.95 ± 14.88 at 24 months) compared with the MFX group (57.78 ± 18.31 at 12 months and 59.5 ± 13.44 at 24 months). Select subdomains (4/5) in the KOOS instrument were significantly different at 12 and 18 months, and all subdomains (Symptoms and Stiffness, Pain, Activities of Daily Living, Sports and Recreation, Knee-related Quality of Life) were significantly increased at 24 months in CAIS with scores of 88.47 ± 11.68, 90.64 ± 7.87, 97.29 ± 3.8, 78.16 ± 22.06, and 69 ± 23.15 compared with 75 ± 9.31, 78.94 ± 13.73, 89.46 ± 8.13, 51.67 ± 26.01, and 37.15 ± 21.67 in the MFX group. These significant improvements were maintained at 24 months in both IKDC and KOOS. Qualitative analysis of the imaging data did not note differences between the 2 groups in fill of the graft bed, tissue integration, or presence of subchondral cysts. Patients treated with MFX had a significantly higher incidence of intralesional osteophyte formation (54% and 70% of total number of lesions treated) at 6 and 12 months when compared with CAIS (8% and 25% of total number of lesions treated).

Conclusion: The first clinical experience in using CAIS for treating patients with focal chondral defects indicates that it is a safe, feasible, and effective method that may improve long-term clinical outcomes.

Background: In recent years, there has been an increasing interest in and awareness of the importance of subchondral bone, for its role in the pathogenesis of articular surface damage and for the care that should be taken when treating such damage.

Purpose: The objective of this pilot clinical study was to test the safety and performance of a newly developed type I collagen-hydroxyapatite nanostructured biomimetic osteochondral scaffold that aims to regenerate cartilage and subchondral bone.

Study Design: Case series; Level of evidence, 4.

Methods: A multilayer gradient nano-composite scaffold was obtained by nucleating collagen type I fibrils with hydroxyapatite nanoparticles. Thirty patients (9 female, 21 male; mean age, 29.3 years) with knee chondral or osteochondral lesions were treated with scaffold implantation. Lesion size varied from 1.5 cm² to 6.0 cm². Twenty-eight patients were followed for 2 years and were clinically evaluated using the International Knee Documentation Committee and Tegner scores. At final follow-up, magnetic resonance imaging evaluation was performed in 24 patients, and they were evaluated with the MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) score.

Results: The Tegner and International Knee Documentation Committee objective and subjective scores improved significantly from the baseline evaluation to the 6-, 12-, and 24-month follow-ups. Further analysis showed a slower recovery but the same results for patients who presented with adverse events, for older patients, for patients who underwent previous surgery, and for those with patellar lesions. In contrast, a faster recovery was observed in active patients. At magnetic resonance imaging evaluation, complete filling of the cartilage and complete integration of the graft was shown in 70% of the lesions. However, the subchondral lamina and bone were considered intact in a minority of cases (7% and 47%, respectively).

Conclusion: This open 1-step procedure was used for the treatment of chondral and osteochondral knee defects. The present pilot study highlighted the safety and potential clinical benefit of the graded biomimetic osteochondral scaffold in promoting bone and cartilage tissue restoration by itself and with good clinical and magnetic resonance imaging results at the 2-year follow-up.

Background: Patellar tendinopathy is a common overuse injury among jumping athletes. No evidence-based treatment guidelines exist. Extracorporeal shockwave therapy (ESWT) appears to be a promising treatment but its effectiveness has not been studied in athletes with patellar tendinopathy who have symptoms for 3 to 12 months and are still playing.

Purpose: The TOPGAME study was created to determine the effectiveness of ESWT on pain, symptoms, and function in athletes with early symptomatic patellar tendinopathy who are still in training and competition.

Study Design: Randomized controlled trial; Level of evidence, 1.

Methods: Athletes playing volleyball, basketball, or handball with patellar tendinopathy for 3 to 12 months were randomized into the ESWT or placebo group during the first half of the season. The ESWT group received 3 ESWT treatments while the placebo group received sham ESWT. In-season follow-up measurements were 1, 12, and 22 weeks after treatment. The primary outcome was severity of patellar tendinopathy determined with the Victorian Institute of Sport Assessment–Patella (VISA-P) questionnaire. Secondary outcome measures were pain during activities of daily living and sports and after functional knee-loading tests rated on a visual analog scale and subjective improvement. Multilevel analyses were performed to determine differences between groups over time.

Results: Of the 127 symptomatic athletes invited to participate, 62 were eligible, gave consent, and were randomized into the ESWT (n = 31) or placebo group (n = 31). Mean VISA-P scores before and 1, 12, and 22 weeks after treatment were 59.4 (±11.7), 66.8 (±16.2), 66.7 (±17.5), and 70.5 (±18.9) for the ESWT group and 62.4 (±13.4), 66.3 (±19.0), 68.9 (±20.3), and 72.7 (±18.0) for the placebo group. For the VISA-P, there was a significant effect for time (P < .01) but no treatment × time interaction effect (P = .82). The same pattern was seen in visual analog scale pain scores. One week after final treatment, significantly more athletes in the ESWT group reported subjective improvement (65% vs 32%; χ² = 6.46, P = .01). This was the only difference noted between the 2 groups.

Conclusion: Extracorporeal shockwave therapy as a solitary treatment during the competitive season has no benefit over placebo treatment in the management of actively competing jumping athletes with patellar tendinopathy who have symptoms for less than 12 months.

Background: Platelet-rich plasma (PRP) has been shown to be a general stimulation for repair and 1-year results showed promising success percentages.

Purpose: This trial was undertaken to determine the effectiveness of PRP compared with corticosteroid injections in patients with chronic lateral epicondylitis with a 2-year follow-up.

Study Design: Randomized controlled trial; Level of evidence, 1.

Methods: The trial was conducted in 2 Dutch teaching hospitals. One hundred patients with chronic lateral epicondylitis were randomly assigned to a leukocyte-enriched PRP group (n = 51) or the corticosteroid group (n = 49). Randomization and allocation to the trial group were carried out by a central computer system. Patients received either a corticosteroid injection or an autologous platelet concentrate injection through a peppering needling technique. The primary analysis included visual analog scale (VAS) pain scores and Disabilities of the Arm, Shoulder and Hand (DASH) outcome scores.

Results: The PRP group was more often successfully treated than the corticosteroid group (P < .0001). Success was defined as a reduction of 25% on VAS or DASH scores without a reintervention after 2 years. When baseline VAS and DASH scores were compared with the scores at 2-year follow-up, both groups significantly improved across time (intention-to-treat principle). However, the DASH scores of the corticosteroid group returned to baseline levels, while those of the PRP group significantly improved (as-treated principle). There were no complications related to the use of PRP.

Conclusion: Treatment of patients with chronic lateral epicondylitis with PRP reduces pain and increases function significantly, exceeding the effect of corticosteroid injection even after a follow-up of 2 years. Future decisions for application of PRP for lateral epicondylitis should be confirmed by further follow-up from this trial and should take into account possible costs and harms as well as benefits.

Background: Concussions affect an estimated 136 000 high school athletes yearly. Computerized neurocognitive testing has been shown to be appropriately sensitive and specific in diagnosing concussions, but no studies have assessed its utility to predict length of recovery. Determining prognosis during subacute recovery after sports concussion will help clinicians more confidently address return-to-play and academic decisions.

Purpose: To quantify the prognostic ability of computerized neurocognitive testing in combination with symptoms during the subacute recovery phase from sports-related concussion.

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

Methods: In sum, 108 male high school football athletes completed a computer-based neurocognitive test battery within 2.23 days of injury and were followed until returned to play as set by international guidelines. Athletes were grouped into protracted recovery (>14 days; n = 50) or short-recovery (≤14 days; n = 58). Separate discriminant function analyses were performed using total symptom score on Post-Concussion Symptom Scale, symptom clusters (migraine, cognitive, sleep, neuropsychiatric), and Immediate Postconcussion Assessment and Cognitive Testing neurocognitive scores (verbal memory, visual memory, reaction time, processing speed).

Results: Multiple discriminant function analyses revealed that the combination of 4 symptom clusters and 4 neurocognitive composite scores had the highest sensitivity (65.22%), specificity (80.36%), positive predictive value (73.17%), and negative predictive value (73.80%) in predicting protracted recovery. Discriminant function analyses of total symptoms on the Post-Concussion Symptom Scale alone had a sensitivity of 40.81%; specificity, 79.31%; positive predictive value, 62.50%; and negative predictive value, 61.33%. The 4 symptom clusters alone discriminant function analyses had a sensitivity of 46.94%; specificity, 77.20%; positive predictive value, 63.90%; and negative predictive value, 62.86%. Discriminant function analyses of the 4 computerized neurocognitive scores alone had a sensitivity of 53.20%; specificity, 75.44%; positive predictive value, 64.10%; and negative predictive value, 66.15%.

Conclusion: The use of computerized neurocognitive testing in conjunction with symptom clusters results improves sensitivity, specificity, positive predictive value, and negative predictive value of predicting protracted recovery compared with each used alone. There is also a net increase in sensitivity of 24.41% when using neurocognitive testing and symptom clusters together compared with using total symptoms on Post-Concussion Symptom Scale alone.

Background: The arthroscopic double-row transosseous-equivalent (TOE) rotator cuff repair is growing in popularity. The current body of literature supports this technique; however, the number of patients in these studies is relatively small. The authors conducted this study to learn more about the natural history of this construct in a large sample of patients.

Hypothesis: The double-row TOE rotator cuff repair will have an acceptable structural failure rate with improved clinical outcomes at 1-year follow-up.

Study Design: Case series; Level of evidence, 4.

Methods: Between June 2006 and October 2007, 225 patients underwent an all-arthroscopic rotator cuff repair at 2 surgical centers. A total of 155 TOE primary rotator cuff repairs were performed, and 154 of these patients met the inclusion criteria. Assessment of structural integrity was based on evaluation of postoperative magnetic resonance imaging or computed tomography arthrogram at a minimum of 12 months after surgery. The Constant scores, visual analog pain scale, range of motion, strength, and complications were the clinical outcomes analyzed for the study. Seventeen patients (of 154) had postoperative shoulder stiffness at follow-up.

Results: The 154 patients were clinically and radiologically evaluated at a mean of 15 months postoperatively (range, 12-26.1 months). The study included 47 small (30.5%), 89 large (57.1%), and 19 massive (12.3%) rotator cuff tears. Analysis of postoperative imaging demonstrated that 92%, 83%, and 84% of the small, large, and massive rotator cuff tears, respectively, were intact. The mean Constant score improved from 44.42 points preoperatively to 80.47 points postoperatively (P < .001). The mean preoperative pain score improved from 3.83 to 12.77 (P < .001) postoperatively. The mean forward flexion improved from 123.06° preoperatively to 162.39° postoperatively (P < .001). Seventeen patients (of 154) had postoperative shoulder stiffness at follow-up.

Conclusion: The short-term results of this study indicate that the clinical outcomes and structural integrity of TOE double-row rotator cuff repair (the suture-bridge technique) have results that compare favorably with those reported for other double-row suture anchor techniques employed in rotator cuff repairs. Long-term follow-up will be necessary to determine if the durability of these repairs and the structural integrity of these constructs maintain their performance over time.

Background: Muscle injuries constitute a large percentage of all injuries in football.

Purpose: To investigate the incidence and nature of muscle injuries in male professional footballers.

Study Design: Cohort study; Level of evidence, 2.

Methods: Fifty-one football teams, comprising 2299 players, were followed prospectively during the years 2001 to 2009. Team medical staff recorded individual player exposure and time-loss injuries. The first-team squads of 24 clubs selected by the Union of European Football Associations as belonging to the best European teams, 15 teams of the Swedish First League, and another 15 European teams playing their home matches on artificial turf pitches were included. A muscle injury was defined as “a traumatic distraction or overuse injury to the muscle leading to a player being unable to fully participate in training or match play.”

Results: In total, 2908 muscle injuries were registered. On average, a player sustained 0.6 muscle injuries per season. A squad of 25 players can thus expect about 15 muscle injuries per season. Muscle injuries constituted 31% of all injuries and caused 27% of the total injury absence. Ninety-two percent of all muscle injuries affected the 4 major muscle groups of the lower limbs: hamstrings (37%), adductors (23%), quadriceps (19%), and calf muscles (13%). Sixteen percent of the muscle injuries were reinjuries. These reinjuries caused significantly longer absences than did index injuries. The incidence of muscle injury increased with age. When separated into different muscle groups, however, an increased incidence with age was found only for calf muscle injuries and not for hamstring, quadriceps, or hip/groin strains.

Conclusion: Muscle injuries are a substantial problem for players and their clubs. They constitute almost one third of all time-loss injuries in men’s professional football, and 92% of all injuries affect the 4 big muscle groups in the lower limbs.

Background: Medial elbow distraction during pitching as the primary mechanism contributing to adaptations in ulnar collateral ligament (UCL) appearance during magnetic resonance imaging (MRI) evaluation has not been established.

Hypothesis: Uninjured high school–aged pitchers with unilateral adaptations of the UCL exhibit a higher peak internal elbow adduction moment than those without UCL adaptations.

Study Design: Cohort study (Prevalence); Level of evidence, 2.

Methods: Twenty uninjured, asymptomatic high school–aged pitchers underwent bilateral elbow MRI examinations. Three-dimensional motion analysis testing was performed to collect throwing arm biomechanics as participants pitched from an indoor mound. Nonparametric tests were performed to compare peak internal elbow adduction moment in uninjured participants with and without adaptations in UCL appearance and to determine the nature of the relationship between the peak internal adduction moment and UCL appearance.

Results: Uninjured participants with UCL thickening exhibited a higher peak internal elbow adduction moment of 53.3 ± 6.8 N·m compared with uninjured participants without adaptations in UCL appearance, 38.8 ± 10.9 N·m (P = .05), as higher moments were correlated with ligament thickening (correlation coefficient, 0.45) (P = .02).

Conclusion: This study establishes the association between medial elbow distraction captured by the internal adduction moment during pitching and UCL adaptations visible during MRI evaluation.

Background: Rehabilitation after anterior cruciate ligament reconstruction is a key determinant affecting patient return to usual activity levels. Neuromuscular electrical stimulation is a treatment that can counteract strength loss and serve as an adjunct to conventional therapy.

Purpose: To compare the effect of adding traditional neuromuscular electrical stimulation (Polystim) or a novel garment-integrated neuromuscular electrical stimulation (Kneehab) to a standard postoperative rehabilitation program (control).

Study Design: Randomized controlled trial; Level of evidence, 1.

Methods: Ninety-six patients, of a total enrolled cohort of 131 patients randomized to 1 of 3 intervention groups, completed a standard rehabilitation program. In addition, the 2 neuromuscular electrical stimulation groups underwent 20-minute sessions of neuromuscular electrical stimulation 3 times a day, 5 days a week, for 12 weeks, in which stimulation was superimposed on isometric volitional contractions. Outcome measures including isokinetic strength of the knee extensors of the injured and uninjured leg at 90 and 180 deg/s, along with functional tests of proprioception, were assessed at baseline and at 6 weeks, 12 weeks, and 6 months postoperatively.

Results: The Kneehab group achieved significantly better results at each time point compared with the Polystim and control groups (P < .001). Extensor strength of the Kneehab group at speeds of 90 and 180 deg/s increased by 30.2% and 27.8%, respectively, between the preoperative measurements and the 6-month follow-up point in the injured leg. The corresponding changes for Polystim were 5.1% and 5%, whereas for the control group they were 6.6% and 6.7%, respectively. The mean single-legged hop test hop score of the Kneehab group improved by 50% between the 6-week and 6-month follow-up, whereas the corresponding changes for the Polystim and control groups were 26.3% and 26.2%, respectively. Although there was no significant difference between the groups with respect to the Tegner score and the International Knee Documentation Committee 2000 knee examination score, the Kneehab group showed a significant difference in mean improvement for the baseline corrected Lysholm score compared with the control group (P = .01; 95% confidence interval, 1.12-8.59) and with the Polystim group (P < .001; 95% confidence interval, 1.34-9.09) with no significant difference evident between Polystim and control groups (P = .97; 95% confidence interval, −4.23 to 3.51).

Conclusion: Intensive garment-integrated stimulation combined with standard rehabilitation is effective at accelerating recovery after knee surgery.

Background: Rotational laxity control is one of the different options to improve functional results after anterior cruciate ligament reconstruction. Lateral extra-articular tenodesis has been proposed to reduce the rotational laxity, especially in challenging situations such as revision reconstruction after biological failure. We currently lack the practical clinical tools to objectively assess knee rotational laxities.

Hypothesis: Addition of a lateral tenodesis to anatomic single-bundle anterior cruciate ligament reconstruction with hamstring tendon graft could improve the knee laxity control, particularly the internal rotation, compared with a standard single-bundle anterior cruciate ligament reconstruction.

Study Design: Controlled laboratory study.

Methods: Twenty patients underwent navigated anatomic anteromedial bundle revision anterior cruciate ligament reconstruction with addition of percutaneous extra-articular tenodesis using the same hamstring tendon graft. The navigation was used to optimize femoral and tibial tunnel positions and to measure the knee kinematics in response to the anterior drawer test, Lachman test, maximum internal/external rotation test, and pivot-shift test. All patients underwent revision after failure without any technical error found or new trauma. Two sequential reconstruction protocols were used to assess the contribution of the extra-articular tenodesis and single anteromedial bundle anterior cruciate ligament reconstruction to restrain tibial translations and coupled axial rotation occurring with the manually performed clinical laxity tests. In group A, the intra-articular reconstruction was fixed first and then the lateral tenodesis was fixed, and in group B, the protocol was reversed. Measurements were performed before the reconstruction, after the first part was fixed, and after the second part was fixed in each protocol.

Results: At 90° of flexion, addition of lateral tenodesis had a significant effect on coupled internal rotation (P = .003). Addition of the intra-articular reconstruction to lateral tenodesis had a significant effect (P = .001) in reducing anterior tibial translation of the medial compartment, and the effect was also significant (P = .0001) in reduction of lateral compartment translation. For the rotational envelope, lateral tenodesis had a significant effect (P = .0001) in reducing maximum internal rotation at 90° of flexion.

Conclusion: Addition of an extra-articular procedure provided no significant improvement to anterior tibial translation and improved internal tibial rotation control only at 90° of flexion.

Background: Results of arthroscopic repair of isolated subscapularis tendon tears have not been widely studied. A detailed evaluation of subscapularis function with subscapularis strength quantification has not been performed to date.

Purpose: To evaluate postoperative subscapularis muscle function and to assess the clinical outcome and structural tendon integrity with postoperative magnetic resonance imaging after arthroscopic repair of isolated subscapularis tears.

Study Design: Case series; Level of evidence, 4.

Methods: In a prospective study, isolated subscapularis tendon tears in 21 patients were treated with an all-arthroscopic repair. The average age of the study population was 43 years. The mean interval between trauma and surgery was 5.8 months. In 19 patients, a traumatic event caused the onset of symptoms. Subscapularis muscle function was assessed with specific clinical tests and the Constant scoring system. Postoperative subscapularis strength was evaluated with a custom-made electronic force measurement plate. All patients underwent postoperative magnetic resonance imaging to assess structural integrity of the repair.

Results: The average duration of follow-up was 27 months. The Constant score increased from 50 points preoperatively to 82 points postoperatively (P < .01). Most positive preoperative lift-off and belly-press tests were reversed by surgery, with a rate of 5 (24%) persistent positive tests after surgery. In operated shoulders, subscapularis strength in the belly-press (65 vs 87 N; P < .05) and the lift-off position (44 vs 68 N; P < .05) was significantly reduced compared with the contralateral shoulder. Magnetic resonance imaging revealed an intact repair in 20 patients. Atrophy of the upper subscapularis muscle portion was present in about one-fourth of the patients and in all patients with a positive postoperative belly-press test.

Conclusion: Arthroscopic repair of isolated subscapularis tendon tears achieves substantial improvement of shoulder function and a low rerupture rate. Despite excellent clinical results, a significant postoperative subscapularis strength deficit compared with the contralateral shoulder persists that can be quantified with use of the force measurement plate. Atrophy of the upper subscapularis muscle is present in 25% of the patients in the postoperative course.

Background: Recent studies have emphasized the importance of anatomic tunnel placement during anterior cruciate ligament (ACL) reconstruction in an effort to restore normal knee kinematics and stability. Secondary to the constraints imposed by a coupled drilling technique, the ability to achieve an anatomic femoral tunnel during transtibial hamstring ACL reconstruction may be limited.

Hypothesis: The size limitations imposed by the small-diameter tibial tunnel used in hamstring ACL reconstruction would preclude the ability to place an anatomic femoral tunnel.

Study Design: Descriptive laboratory study.

Methods: In a descriptive laboratory study, fresh-frozen human cadaveric knees fixed at 90° of flexion were dissected to expose the centers of the native femoral and tibial ACL insertions. The geometry and location of each insertion were evaluated. Using a standardized starting point, tibial tunnels were drilled to the center of the tibial insertion using an 8-mm reamer. Next, a 6-mm over-the-top guide was used to position as close as possible to the anatomic femoral ACL insertion on the lateral wall, and femoral tunnels were drilled with the 8-mm reamer. For each tunnel, the location, geometry, and percentage overlap with the native insertion site were evaluated using a 3-dimensional laser scanner.

Results: The reamed tibial tunnel was central within the insertion site, occupying 40.4% ± 2.0% of the native tibial insertion. Transtibial drilling resulted in femoral tunnels that were superior and posterior compared with the native femoral insertion. Thefemoral tunnel had a mean ± SD overlap of 30.0% ± 12.6% with the femoral insertion, with the center of the tunnel 7.6± 0.5 mm from the center of the native ACL femoral insertion.

Conclusion: Based on our data using our specific starting point, during hamstring ACL reconstructions, the constraints imposed by a coupled drilling technique result in nonanatomic femoral tunnels that are superior and posterior to the native femoral insertion.

Clinical Relevance: Anatomic femoral tunnel placement during hamstring ACL reconstructions may not be possible using a coupled, transtibial drilling approach.

Background: Sterile surgical marker pens are commonly used in cartilage repair surgery to aid in the placement of periosteal patches or collagen membranes in autologous chondrocyte implantation.

Purpose: To investigate the effects that methylene blue and crystal violet marker pen ink have on human chondrocytes when cultured on collagen membranes in vitro.

Study Design: Controlled laboratory study.

Methods: Human chondrocytes were applied to Chondro-Gide collagen membranes at a volume of 12 million cells. In the first experiment, 2 sterile marker pens, one containing methylene blue and the other crystal violet inks, were used to mark membranes immediately before the addition of cells. In the second experiment, the same marker pens marked the membranes after 7 days of cell culture. In each experiment, 3 groups of membrane were tested for each pen. Group A consisted of no ink mark, group B had only the uppermost “smooth” layer marked, and group C had the lower “porous” layer marked. All membranes were then cultured in standard growth media for 24 hours. Cell viability was assessed at 24 hours on all membranes using a live/dead-cell viability assay. Cell viability was quantified with florescent microscopy with mean percentage of live cells in each marker pen group compared with control membranes using the Student t test (P < .05).

Results: Control membranes (group A) with no ink showed cell viability approaching 100%. A statistically significant reduction in cell viability with both methylene blue (23.1%; P < .0001) and crystal violet (18.9%; P < .0001) was found adjacent to the ink mark on the smooth side (group B) and on the porous side remote from the ink (group C) in both experiments (<30%; P < .0001). Areduction in cell viability was noted on the smooth side remote from the ink mark but did not reach statistical significance. Marked cell death was seen with both dyes (<15%; P < .0001) adjacent to the ink on the porous side.

Conclusion: Chondrocyte viability is significantly reduced when cells are cultured in vitro on collagen membranes marked with methylene blue and crystal violet pen ink.

Clinical Relevance: Surgeons should be aware of the potential negative effect of marker pens in cell-based therapies.

Background: Although stress radiography is frequently used to assess abnormal knee instability, the reliability and reproducibility for an evaluation of anterior-posterior instability of the knee may be affected by a variety of factors.

Hypothesis: Different measurement methods result in different levels of reliability and reproducibility for instability; there may be a novel method that is more reliable and relatively unaffected by slight changes in flexion and rotation.

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

Methods: Stress radiographs of 40 patients with anterior cruciate ligament injury or reconstruction and 40 patients with posterior cruciate ligament injury or reconstruction were taken using the Telos device. The values of 4 conventional methods (medial-medial, lateral-lateral, middle-middle, and peripheral-central) and 1 newly devised method (Blumensaat line–anterior tibia) were compared. Intraclass correlation coefficients were examined to assess intraobserver and interobserver reliability of the measurements. For an evaluation of the reproducibility of each method, stress radiographs were taken twice (before and after the examination at the outpatient clinic) on the same day, and the values from the first and second stress radiographs were compared.

Results: In the anterior drawer test, as to measurement reliability, the ranges of intraclass correlation coefficients were 0.713 to 0.889 for medial-medial, 0.624 to 0.812 for lateral-lateral, 0.834 to 0.932 for middle-middle, 0.722 to 0.892 for peripheral-central, and 0.891 to 0.963 for Blumensaat line–anterior tibia. As to test-retest reproducibility, the mean differences (SD) of displacement between the first and second radiograph were 1.0 (0.8) mm for medial-medial, 2.4 (2.3) mm for lateral-lateral, 1.7 (1.6) mm for middle-middle, 1.2 (0.6) mm for peripheral-central, and 0.5 (0.7) mm for Blumensaat line–anterior tibia. In the posterior drawer test, as to measurement reliability, the ranges of intraclass correlation coefficients were 0.859 to 0.958 for medial-medial, 0.773 to 0.915 for lateral-lateral, 0.859 to 0.951 for middle-middle, 0.852 to 0.958 for peripheral-central, and 0.893 to 0.961 for Blumensaat line–anterior tibia. Asto test-retest reproducibility, the mean differences (SD) of displacement between the first and second radiographs were 1.6 (1.3)mm for medial-medial, 1.8 (1.7) mm for lateral-lateral, 1.7 (1.5) mm for middle-middle, 1.4 (1.1) mm for peripheral-central, and 1.1 (1.2) mm for Blumensaat line–anterior tibia.

Conclusion: Different methods of measuring stress radiographs resulted in different levels of reliability and reproducibility. In the anterior drawer test, the Blumensaat line–anterior tibia method showed the best measurement reliability and test-retest reproducibility. In the posterior drawer test, the Blumensaat line–anterior tibia method showed favorable measurement reliability and reproducibility, but the superiority could not be demonstrated.

Background: Rotator cuffs heal through a scar tissue interface after repair that makes them prone to failure. Scleraxis (Scx) is a basic helix-loop-helix transcription factor that is thought to direct tendon development during embryogenesis. The purpose of this study was to determine if the application of mesenchymal stem cells (MSCs) transduced with adenoviral-mediated scleraxis (Ad-Scx) could improve regeneration of the tendon-bone insertion site in a rat rotator cuff repair model.

Hypothesis: Bone marrow–derived cells transduced with Scx would improve the structure of the healing tendon-bone interface and result in increased tendon attachment strength.

Study Design: Controlled laboratory study.

Methods: Sixty Lewis rats underwent unilateral detachment and repair of the supraspinatus tendon. Thirty animals received MSCs in a fibrin glue carrier, and 30 received Ad-Scx-transduced MSCs. Animals were sacrificed at 2 weeks and 4 weeks and evaluated for the presence of fibrocartilage and collagen fiber organization at the insertion. Biomechanical testing was performed to determine the structural and material properties of the repaired tissue. Statistical analysis was performed with a Wilcoxon rank sum test with significance set at P = .05.

Results: There were no differences between the Scx and MSC groups in terms of histologic appearance at 2 weeks. However, the Scx group had higher ultimate stress-to-failure (2.6 ± 0.9 vs 1.7 ± 0.3 MPa; P = .03) and stiffness (8.4 ± 2.9 vs 5.0 ± 1.9 N/mm; P = .01) compared with the MSC group. At 4 weeks, the Scx group had more fibrocartilage (728.7 ± 50.4 vs 342.6 ± 217.0 mm²; P = .04), higher ultimate load to failure (26.7 ± 4.6 vs 20.8 ± 4.4 N; P = .01), higher ultimate stress to failure (4.7 ± 1.3 vs 3.5 ± 1.0 MPa; P < .04), and higher stiffness values (15.3 ± 3.4 vs 9.3 ± 2.2 N/mm; P < .001) as compared with the MSC group.

Conclusion: Mesenchymal stem cells genetically modified with Scx can augment rotator cuff healing at early time points.

Clinical Relevance: Biologic augmentation of acutely injured rotator cuffs with Scx-transduced MSCs may improve rotator cuff tendon healing and reduce the incidence of re-tears. However, further studies are needed to determine if this remains safe and effective in larger models.

Background: Outcomes of arthroscopic type II superior labral anterior posterior (SLAP) repairs have been reported with success. However, published data regarding outcomes of revision arthroscopic type II SLAP repairs are lacking.

Hypothesis: Outcomes of revision arthroscopic type II SLAP repairs are inferior to those of primary repairs.

Study Design: Case series; Level of evidence, 4.

Methods: A retrospective chart review was performed to identify patients who had undergone revision arthroscopic type II SLAP repairs at our institution. Patients who underwent concomitant rotator cuff repairs or labral repairs for instability were excluded. Twelve patients were contacted, and the following outcome data were prospectively gathered: American Shoulder and Elbow Surgeons (ASES) score, patient satisfaction level, return to work, return to sports, and physical examination. Demographics and intraoperative report data were also collected from the charts.

Results: The mean age at the time of revision arthroscopic type II SLAP repairs was 32.6 years (range, 19-67 years) with a mean follow-up of 50.5 months (range, 8-81 months). There were 5 workers’ compensation patients and 6 overhead athletes. Pain was the chief complaint at the time of initial and revision SLAP repairs. The mean ASES score was 72.5, patient satisfaction level was 6.4 (scale of 0-10), mean return to work was at 57.8% of the previous level, and mean return to sports was at 42.2% of the previous level. In overhead athletes, mean return to sports was at 41.3% of the previous level, and none of the 4 baseball players returned to preinjury level. The mean values for all outcome data and range of motion values were lower in workers’ compensation patients. There were no reported complications, but 2 patients required additional arthroscopic surgeries.

Conclusion: Arthroscopic revision type II SLAP repairs yield worse results than primary repairs as reported in the literature, with workers’ compensation patients and overhead athletes doing especially worse. A larger prospective study of this relatively rare procedure is needed to better determine which patients may benefit from this procedure.

Background: Internal fixation is a popular first-line treatment method for proximal fifth metatarsal Jones fractures in athletes; however, nonunions and screw breakage can occur, in part because of nonspecific fixation hardware and poor blood supply.

Purpose: To report the results from 26 patients who underwent percutaneous internal fixation with a specialized screw system of a proximal fifth metatarsal Jones fracture (zones II and III) and bone marrow aspirate concentrate.

Study Design: Case series; Level of evidence, 4.

Methods: Percutaneous internal fixation for a proximal fifth metatarsal Jones fracture (zones II and III) was performed on 26 athletic patients (mean age, 27.47 years; range, 18-47). All patients were competing at some level of sport and were assessed preoperatively and postoperatively using the Foot and Ankle Outcome Score and SF-12 outcome scores. The mean follow-up time was 20.62 months (range, 12-28). Of the 26 fractures, 17 were traditional zone II Jones fractures, and the remaining 9 were zone III proximal diaphyseal fractures.

Results: The mean Foot and Ankle Outcome Score significantly increased, from 51.15 points preoperatively (range, 14-69) to 90.91 at final follow-up (range, 71-100; P < .01). The mean physical component of the SF-12 score significantly improved, from 25.69 points preoperatively (range, 6-39) to 54.62 at final follow-up (range, 32-62; P < .01). The mean mental component of the SF-12 score also significantly improved, from 28.20 points preoperatively (range, 14-45) to 58.41 at final follow-up (range, 36-67; P < .01). The mean time to fracture healing on standard radiographs was 5 weeks after surgery (range, 4-24). Two patients did not return to their previous levels of sporting activity. One patient experienced a delayed union, and 1 healed but later refractured.

Conclusion: Percutaneous internal fixation of proximal fifth metatarsal Jones fractures, with a Charlotte Carolina screw and bone marrow aspirate concentrate, provides more predictable results while permitting athletes a return to sport at their previous levels of competition, with few complications.

Background: Calcium deposits within the tendons of the rotator cuff are common and usually asymptomatic. Symptomatic cases that do not respond to nonoperative measures need removal of the calcium deposits.

Purpose: In this study, the results of arthroscopic removal of the calcium deposits within the rotator cuff, without rotator cuff repair, are evaluated after a minimum 7-year follow-up. This may help clarify whether rotator cuff repair in such cases is necessary for the relief of pain and good cuff function in the long run.

Study Design: Case series; Level of evidence, 4.

Methods: Fifty-six patients with calcium deposits within the rotator cuff were included in this study. Fifty-four patients were managed by arthroscopic removal of the calcium deposits without rotator cuff repair.

Results: The patients were followed up over a period of at least 7 years. At the final follow-up, all patients were able to return to their level of activity before the beginning of their complaint, with significant improvement in the University of California at Los Angeles (UCLA), American Shoulder and Elbow Surgeons (ASES), and Constant scores. The UCLA score improved from a mean (SD) of 52.8 (7.5) to 95.0 (8.2) (P ≤ .001), whereas the ASES score improved from 57.2 (8.3) to 95.0 (8.2) (P ≤ .001). The Constant score improved from a mean (SD) of 63.3 (9.3) to 97.8 (6.2) (P ≤ .001). Only 3.7% of cases developed rotator cuff tears over the period of follow-up.

Conclusion: The results of this study indicate that arthroscopic removal of as much as possible of symptomatic calcium deposits of the rotator cuff is a safe and effective treatment when nonoperative methods fail.

Background: Recent reports have suggested that a traditional transtibial technique cannot practically accomplish an anatomic anterior cruciate ligament (ACL) reconstruction.

Hypothesis: The degree to which a transtibial technique can anatomically position both tibial and femoral tunnels is highly dependent on tibial tunnel starting position.

Study Design: Descriptive laboratory study.

Methods: Eight fresh-frozen adult knee specimens were fixed at 90° of flexion and then dissected to expose the femoral and tibial ACL footprints. After the central third patellar tendon length was measured for each specimen, computer-assisted navigation was used to identify 2 idealized tibial tunnel starting points, optimizing alignment with the native ligament in the coronal plane but distal enough on the tibia to provide manageable bone-tendon-bone autograft–tibial tunnel mismatch (point A = 10-mm mismatch; point B = 0-mm mismatch). Tibial tunnels were then reamed to the center of the tibial insertion using point A in half of the knees and point B in the other half. Guide pin positioning on the femoral side was then assessed before and after tibial tunnel reaming, after beveling the posterolateral tibial tunnel rim, and after performing a standard notchplasty. After the femoral tunnel was reamed, the digitized contours of the native insertions were compared with those of both tibial and femoral tunnels to calculate percentage overlap.

Results: Starting points A and B occurred 15.9 ± 4.5 mm and 33.0 ± 3.3 mm distal to the joint line, respectively, and 9.8 ± 2.4 mm and 8.3 ± 4.0 mm from the medial edge of the tibial tubercle, respectively. The anterior and posterior aspects of both tibial tunnels’ intra-articular exits were within a few millimeters of the native insertion’s respective boundaries. After the tibial tunnel was reamed from the more proximal point A, a transtibial guide pin was positioned within 2.1 ± 1.6 mm of the femoral insertion’s center (vs 9.3 ± 1.9 mm for point B; P = .02). After beveling a mean 2.6 mm from the back of the point A tibial tunnels, positioning improved to within 0.3 ± 0.7 mm from the center of the femoral insertion (vs 4.2 ± 1.1 mm for the point B tibial tunnels; P = .008). Compared with the more distal starting point, use of point A provided significantly greater insertional overlap (tibial: 97.9% ± 1.4% vs 71.1% ± 15.1%, P = .03; femoral: 87.9% ± 9.2% overlap vs 59.6% ± 8.5%, P = .008). No significant posterior femoral or tibial plateau breakthrough occurred in any specimen.

Conclusion: Tibial and femoral tunnels can be positioned in a highly anatomic manner using a transtibial technique but require careful choice of a proximal tibial starting position and a resulting tibial tunnel that is at the limits of practical. Traditional tibial tunnel starting points will likely result in less anatomic femoral tunnels.

Clinical Relevance: A transtibial single-bundle technique can accomplish a highly anatomic reconstruction but does require meticulous positioning of the tibial tunnel with little margin for error and some degree of graft-tunnel mismatch.

Background: Cold water immersion reduces exercise-induced muscle damage. Benefits may partly arise from a decline in limb blood flow; however, no study has comprehensively investigated the influence of different degrees of cooling undertaken via cold water immersion on limb blood flow responses.

Purpose: To determine the influence of cold (8°C) and cool (22°C) water immersion on lower limb and cutaneous blood flow.

Study Design: Controlled laboratory study.

Methods: Nine men were placed in a semireclined position and lowered into 8°C or 22°C water to the iliac crest for two 5-minute periods interspersed with 2 minutes of nonimmersion. Rectal and thigh skin temperature, deep and superficial muscle temperature, heart rate, mean arterial pressure, thigh cutaneous blood velocity (laser Doppler), and superficial femoral artery blood flow (duplex ultrasound) were measured during immersion and for 30 minutes after immersion. Indices of vascular conductance were calculated (flux and blood flow/mean arterial pressure).

Results: Reductions in rectal temperature (8°C, 0.2° ± 0.1°C; 22°C, 0.1° ± 0.1°C) and thigh skin temperature (8°C, 6.2° ± 0.5°C; 22°C, 3.2° ± 0.2°C) were greater in 8°C water than in 22°C (P < .01). Femoral artery conductance was reduced to a similar extent immediately after immersion (~30%) and 30 minutes after immersion (~40%) under both conditions (P < .01). In contrast, there was less thigh cutaneous vasoconstriction during and after immersion in 8°C water compared with 22°C (P = .01).

Conclusion: These data suggest that immersion at both temperatures resulted in similar whole limb blood flow but, paradoxically, more blood was distributed to the skin in the colder water. This suggests that colder temperatures may be associated with reduced muscle blood flow, which could provide an explanation for the benefits of cold water immersion in alleviating exercise-induced muscle damage in sports and athletic contexts.

Clinical Relevance: Colder water temperatures may be more effective in the treatment of exercise-induced muscle damage and injury rehabilitation because of greater reductions in muscle blood flow.

Background: Ballet movements require a limited base of support; thus, ballet dancers require a high level of postural control. However, postural stability in ballet dancers is still unclear and needs to be understood.

Purpose: To evaluate ballet dancers’ postural stability in performing single-leg standing, the en pointe task, and the first and fifth positions and to determine differences in task performance among healthy nondancers, healthy dancers, and dancers with ankle sprains.

Study Design: Controlled laboratory study.

Methods: Injured dancers, uninjured dancers, and nondancers were recruited for this study (N = 33 age-matched participants; n= 11 per group). The tasks tested were single-leg standing with eyes open and closed, first position, fifth position, and en pointe. Center of pressure parameters were calculated from the ground-reaction force collected with 1 force plate. Analysis of variance was used to assess the differences of center of pressure parameters among 3 groups in single-leg standing; independent t test was used to examine the differences of center of pressure parameters between injured and uninjured dancers.

Results: During single-leg standing, injured dancers had significantly greater maximum displacement in the medial-lateral direction and total trajectory of center of pressure, compared with the uninjured dancers and nondancers. During the first and fifth positions, the injured dancers demonstrated significantly greater standard deviation of center of pressure position in the medial-lateral and anterior-posterior directions, compared with the uninjured dancers. During en pointe, the injured dancers had significantly greater maximum displacement in the medial-lateral direction and the anterior-posterior direction, compared with the uninjured dancers.

Conclusion: The injured and uninjured dancers demonstrated differences in postural stability in the medial-lateral direction during single-leg standing and the ballet postures. Although the injured dancers received ballet training, their postural stability may still be inferior to that of the nondancers.

Clinical Relevance: This study is a first step in understanding that injured ballet dancers do not have the same postural stability as uninjured dancers and that it is even inferior to that of nondancers, which is important to understand for further study on rehabilitation. The future development of effective balance training programs for ballet dancers with ankle injuries should emphasize improvements in medial-lateral directional balance.

Injury to the posteromedial corner (PMC) of the knee differs anatomically and biomechanically from isolated injury to the medial collateral ligament. Newer anatomic and biomechanical studies are refining the field’s understanding of the medial side of the knee, as well as its role in multiple ligament injuries. Valgus instability places additional strain on a reconstructed anterior or posterior cruciate ligament, which can contribute to late graft failure. Injuries to the PMC may not heal without surgical repair or reconstruction, particularly when part of a multiple-ligament injury. Identification of PMC injury before cruciate reconstruction is important so that appropriate repair or reconstruction of the PMC and medial collateral ligament can be undertaken at the same time. This article reviews the relevant literature on the PMC, discusses reasons for selective operative management, and illustrates reconstructive strategies for PMC injuries occurring as part of a medial-sided or multiligament injury to the knee.

Groin injuries are a common occurrence in elite-level athletes. These injuries can cause significant pain and disability, leading to prolonged periods of inactivity and consternation among athletes, coaches, athletic trainers, and physicians alike. The differential diagnosis for groin pain is vast and spans multiple disciplines, including orthopaedics, general surgery, urology, gynecology, and neurology.

Sports hernias are one cause of chronic groin pain in athletes and are distinct entities from classic hernias. They are often caused by a deficient posterior wall of the inguinal canal, but may also involve concurrent injuries, such as conjoint and adductor tendinopathies and nerve entrapment. Understanding the complex lower abdominal, pelvic, and hip anatomy and pathophysiology of sports hernias is crucial to making an accurate diagnosis and providing appropriate treatment options. Newer, less invasive surgical repair techniques show promising early results in improving pain and decreasing recovery time.