Biomechanical Response to Distraction of Hip Capsular Reconstruction With Human Acellular Dermal Patch Graft.

PURPOSE: To quantify the biomechanical properties of the hip capsule with human dermal allograft reconstruction to determine whether a dermal patch restored capsular resistance to distraction. METHODS: Nine cadaveric hip specimens were dissected until capsule and bony structures remained and were then mounted in a testing fixture in neutral flexion and abduction. Four states of the hip capsule were sequentially tested under axial distraction of 5 mm measured with video analysis and with resultant force measurement: (1) intact hip capsule, (2) interportal capsulotomy, (3) capsulectomy to the zona orbicularis, and (4) capsular reconstruction with human dermal allograft using acetabular anchors and capsule-to-patch sutures. RESULTS: Capsulectomy was different from intact (P = .036), capsulotomy differed from capsulectomy (P = .012), and the repair was statistically significantly different from capsulectomy (P = .042); intact and reconstructed cases were not statistically significantly different. The force required for 5 mm of distraction decreased after interportal capsulotomy by an average of 9% compared with the intact state and further decreased after capsulectomy by 30% compared with the intact state. After capsular reconstruction using dermal allograft, force requirements increased by an average of 36% from the capsulectomy state, only 5% below the intact state. CONCLUSIONS: Human dermal allograft tissue graft provides restoration of distractive strength for use during hip capsule reconstruction with acetabular anchor fixation and distal soft-tissue fixation after capsulectomy in a cadaveric model. CLINICAL RELEVANCE: Capsular repair or reconstruction with a dermal patch offers time-zero restoration of function; intact and reconstructed cases showed no difference, and reconstruction restored a capsulectomy to a biomechanical equivalent of the intact case when distraction was applied.

Reconstruction of the Acromioclavicular Ligament Complex Using Dermal Allograft: A Biomechanical Analysis.

PURPOSE: To analyze the posterior translational and rotational stability of the acromioclavicular (AC) joint following reconstruction of the superior acromioclavicular ligament complex (ACLC) using dermal allograft. METHODS: Six fresh-frozen cadaveric shoulders were used (mean age of 65.3 ± 6.9 years). The resistance force against posterior translation (10 mm) and torque against posterior rotation (20°) was measured. Specimens were first tested with both the intact ACLC and coracoclavicular ligaments. The ACLC and coracoclavicular ligaments were then transected so simulate a Type III/V AC joint dislocation. Each specimen then underwent 3 testing conditions, performed in the following order: (1) ACLC patch reconstruction alone, (2) ACLC patch with an anatomic coracoclavicular reconstruction (ACCR) using semitendinosus allograft, and (3) the transected ACLC with an ACCR only. Differences in posterior translational and rotational torque across testing conditions were analyzed with a one-way repeated analysis of variance analysis. RESULTS: Mean resistance against posterior translation in the intact condition was 65.76 ± 23.8 N. No significant difference found between the intact condition compared with specimens with the ACLC-patch only (44.2 ± 11.3 N, P = .06). The ACCR technique, when tested alone, had significantly less posterior translational resistance compared with the intact condition (38.5 ± 8.94 N, P = .008). ACLC patch in combination with an ACCR was closest in restoring native posterior translation (57.1 ± 19.2 N, P = .75). For rotational resistance, only the addition of the ACLC patch with an ACCR (0.51 ± 0.07 N-m) demonstrated similar torque compared with the intact joint (0.89 ± 0.5 N-m, P = .06). CONCLUSIONS: The ACLC-patch plus ACCR technique was able to closest restore the percent of normal posterior translational and rotational stability. CLINICAL RELEVANCE: Recurrent posterior instability of the AC joint is a potential complication after coracoclavicular reconstruction surgery. In the in vitro setting, this study demonstrated increased AC joint stability with the addition of an ACLC reconstruction using dermal allograft.

Posterior shoulder tightness can be a risk factor of scapular malposition: a cadaveric biomechanical study.

BACKGROUND: Scapular malposition and posterior shoulder tightness are key pathologic processes in the shoulder of throwing athletes. The objective of this study was to investigate the effects of posterior capsule tightness, posterior rotator cuff muscle tightness, or both on scapular position. METHODS: Ten shoulders from 5 fresh frozen cadaveric male torsos were tested in maximum internal, neutral, and maximum external shoulder rotations at 0°, 45°, and 90° of shoulder abduction. Scapular rotation-namely, upward and downward rotation, internal and external rotation, and anterior and posterior tilt-and the scapula-spine distance were measured by using a MicroScribe digitizer (Revware, Raleigh, NC, USA). Each shoulder underwent 4 experimental stages: intact; isolated posterior rotator cuff muscle (infraspinatus and teres minor) tightness; both posterior rotator cuff muscle and capsule tightness; and isolated posterior capsule tightness. RESULTS: Posterior muscle tightness significantly decreased upward rotation (P< .05) only in maximum shoulder internal rotation at 45° or 90° of shoulder abduction, whereas posterior capsule tightness did not affect upward rotation (P= .09 to .96). Posterior capsule tightness significantly increased scapular internal rotation (P< .01), but posterior muscle tightness did not change scapular internal rotation (P= .62 to .89). Posterior capsule tightness significantly increased both the superior and inferior scapula-spine distance (ie, caused scapular protraction) in maximum shoulder external rotation at 90° of abduction (P< .01). CONCLUSION: Posterior shoulder tightness resulted in scapular malposition. However, the muscular and capsular components of that tightness affected the scapular position differently. For the treatment of scapula malposition, stretching of the posterior shoulder capsule and muscles is recommended.

Anatomical superficial medial collateral ligament reconstruction with posteromedial capsule reefing successfully restores valgus knee laxity.

The goal of this study was to present the results of an anatomical superficial medial collateral ligament (sMCL) reconstruction combined with reefing of the posteromedial capsule in a series of 10 patients with symptomatic valgus instability complaints in combined injuries of the knee. All patients under- went an sMCL reconstruction with reefing of the posteromedial capsule. If cruciate ligament insuf- ficiency was present, this was reconstructed as well. Pre- and postoperatively, multiple subjective knee outcome scores were obtained, and valgus stress radiographs objectively evaluated laxity. Median valgus laxity of the injured knee on valgus stress radiographs improved significantly. There was no statistically significant difference between post- operative valgus laxity of the injured knee and valgus laxity of the uninjured knee. All subjective knee outcome scores improved significantly compared with the preoperative situation. The described procedure restores valgus laxity to a level comparable to the uninjured knee.

Magnetic resonance imaging predictors of shoulder instability in adolescents.

BACKGROUND: Managing recurrent shoulder instability in an athlete of any age is challenging. The pediatric literature regarding recurrence of instability is difficult to interpret because of the variable treatment protocols and varying ages. The adult literature suggests that bone loss on the humerus, glenoid or both, as detected by CT, has high rates of recurrence following surgical intervention. OBJECTIVE: The purpose of this study was to evaluate risk factors for recurrence following arthroscopic capsulorrhaphy in adolescent athletes using preoperative MR arthrograms. MATERIALS AND METHODS: We reviewed a retrospective shoulder instability database for adolescents (age ≤18 years), who underwent an isolated arthroscopic capsulorrhaphy from 2006 to 2011. We recorded preoperative MRI measurements regarding the dimensions of the glenohumeral joint, as well as glenoid, humeral and labral pathologies. We performed statistical analysis to determine MRI findings that might have predicted recurrence of shoulder instability following capsulorrhaphy. RESULTS: We reviewed a total of 50 patients (13-18 years) and found 22 patients (44%) to have recurrent instability following capsulorrhaphy. Presence of glenoid bone loss or a bipolar bone lesion (defined as bone loss on both the glenoid and humerus) significantly predicted recurrence of shoulder instability (both P=0.03). There was not a threshold size of glenoid bone loss or bipolar lesion that predicted recurrence. All remaining glenohumeral dimensions or presence or size of an isolated Hill-Sachs did not significantly predict recurrence of instability. CONCLUSION: Athletes ≤18 years old have a high rate of failure following arthroscopic capsulorrhaphy in the presence of glenoid bone loss or a bipolar lesion on MRI. Surgeons should consider addressing these lesions in adolescent athletes with shoulder instability. Additionally, MRI is a valid imaging tool to diagnose and measure osseous lesions of the shoulder.

Symptomatic medial synovial plica of the knee joint: an underestimated pathology in young patients.

INTRODUCTION: To prospectively evaluate the outcome of arthroscopic resection of a symptomatic medial plica in patients under 30 years with evaluating the influence of sports, knee trauma and plica type. METHODS: 35 consecutive patients (38 knees), mean age 16.2 ± 4.7 years (9-26 years), 28 females (73.7%) were prospectively included. Patients with any additional surgical procedures or cartilage lesions > ICRS grade I were excluded. The influence of trauma to the knee, level of sport and the morphologic plica type on the outcome was evaluated in addition to standard knee scores before and 20.1 ± 9.3 months (12-44 months) after surgery. RESULTS: The Knee Injury and Osteoarthritis Outcome Score improved significantly from 50.2 ± 19.1% (12.5-94.6) to 80.7 ± 15.3% (48.2-100; p < 0.001). The Tegner Activity Scale improved significantly from 2.2 ± 1.5 (0-6) to 4.9 ± 1.7 (3-10; p < 0.001) and the Kujala Anterior Knee Pain Scale improved significantly from 52.6 ± 16.6 (16-86) to 80.7 ± 16.5 (46-100; p < 0.001). The level of pain in the knee decreased from 7.9 ± 2.0 (1-10) to 3.1 ± 2.6 (0-9; p < 0.001) at follow-up on a numeric rating scale (0-10). Neither trauma to the knee, high impact sport, cartilage lesions to the medial femoral condyle nor the plica type or associated ICRS grade I cartilage lesion to the medial femoral condyle had a significant effect on the outcome parameters. CONCLUSION: Arthroscopic resection of a symptomatic medial plica provides excellent clinical results in young patients. Trauma, high impact sports, ICRS grade I cartilage lesions to the medial femoral condyle or the plica type are not associated with a poorer outcome. LEVEL OF EVIDENCE: Level IV, prospective case series with no control group.

[Arthroscopic Superior Capsule Reconstruction Using the DX Reinforcement Matrix in Patients with Irreparable Rotator Cuff Tears - Pilot Data]. / První výsledky artroskopické rekonstrukce horní kapsuly ramenního kloubu u nereparabilní ruptury manzety rotátoru pomocí DX Reinforcement Matrix.

PURPOSE OF THE STUDY Irreparable rotator cuff tear continues to be a point of discussion. Several surgical techniques have been proposed so far. None of them, however, can be considered the method of choice. This study presents the first clinical results of superior capsule reconstruction (SCR) using the DX Reinforcement Matrix. MATERIAL AND METHODS The evaluation included patients with the minimum follow-up of 6 months. The follow-up period in these patients was 1 year (6-18 months) on average. The active (AROM) and passive (PROM) ranges of motion were assessed-anterior flexion, abduction, external rotation and external rotation at 90° abduction. The patients were assessed using clinical scores before and after the surgery-pain assessment scale (VAS), UCLA (University of California at Los Angeles) Shoulder Rating Scale and ASES (American Shoulder and Elbow Surgeons) Shoulder Score. RESULTS In the period from October 2016 to October 2018, a total of 20 SCRs were performed. The mean age of patients was 61 years. Nine patients were clinically assessed, with the mean follow-up of 1 year. The mean UCLA Shoulder Score was 10 points preoperatively. Postoperatively, the values went up to 29 points on average. The reported ASES score was 23.8 points preoperatively. Postoperatively, the mean score was 73.2 points. The VAS subjective pain score ranged around 7 points before the surgery. After the surgery, the mean VAS score was 2 points. The mean active shoulder flexion was 74° preoperatively and 161° postoperatively. The mean active abduction was 74° preoperatively and 161° postoperatively. The mean active external rotation of the shoulder joint was 20° preoperatively and 56° postoperatively. The mean active external rotation at 90° abduction was 21° preoperatively and 82° postoperatively. The changes in all the followed-up mean parameters of UCLA, ASES, VAS, AROM and PROM reported by our group show a relatively high level of substantive significance. DISCUSSION Results of arthroscopic superior capsule reconstruction using the DX Reinforcement Matrix have not been published in literature so far. Compared to the results for fascia lata published in literature, our results are slightly worse. By contrast, our results are similar to those achieved by human dermal allograft. CONCLUSIONS Arthroscopic superior capsule reconstruction currently appears to be the method of choice in unreconstructed supraspinatus and infraspinatus tear. Our group of patients shows that early clinical outcomes of SCR using xenograft are very promising. A significant pain relief and a considerable improvement in the range of motion of the operated shoulder joint were observed. No complication specifically associated with the use of xenograft has been reported as yet. A longer follow-up period and assessment of a larger group of patients will be necessary to confirm the success of this surgical procedure. Key words: massive rotator cuff tears; irreparable rotator cuff tears; superior capsular reconstruction; xenograft; DX Reinforcement Matrix.

Temporal Patterns of Motion in Flexion-extension and Pronation-supination in a Rat Model of Posttraumatic Elbow Contracture.

BACKGROUND: The elbow is highly susceptible to contracture, which affects up to 50% of patients who experience elbow trauma. Previously, we developed a rat model to study elbow contracture that exhibited features similar to the human condition, including persistently decreased ROM and increased capsule thickness/adhesions. However, elbow ROM was not quantitatively evaluated over time throughout contracture development and subsequent mobilization of the joint. QUESTIONS/PURPOSES: The purposes of this study were (1) to quantify the time-dependent mechanics of contracture, including comparison of contracture after immobilization and free mobilization; and (2) to determine what changes occur in capsule and joint surface morphology that may support the altered joint mechanics. METHODS: A total of 96 male Long-Evans rats were randomized into control and injury (unilateral soft tissue injury/immobilization) groups. Flexion-extension and pronation-supination joint mechanics (n = 8/group) were evaluated after 3, 7, 21, or 42 days of immobilization (IM) or after 42 days of IM with either 21 or 42 days of free mobilization (63 or 84 FM, respectively). After measuring joint mechanics, a subset of these limbs (n = 3/group) was prepared for histologic analysis and blinded sections were scored to evaluate capsule and joint surface morphology. Joint mechanics and capsule histology at 42 IM and 84 FM were reported previously but are included to demonstrate the full timeline of elbow contracture. RESULTS: In flexion-extension, injured limb ROM was decreased compared with control (103° ± 11°) by 21 IM (70° ± 13°) (p = 0.001). Despite an increase in injured limb ROM from 42 IM (55° ± 14°) to 63 FM (83° ± 10°) (p < 0.001), injured limb ROM was still decreased compared with control (103° ± 11°) (p = 0.002). Interestingly, ROM recovery plateaued because there was no difference between injured limbs at 63 (83° ± 10°) and 84 FM (73° ± 19°) (p > 0.999). In pronation-supination, increased injured limb ROM occurred until 7 IM (202° ± 32°) compared with control (155° ± 22°) (p = 0.001), representative of joint instability. However, injured limb ROM decreased from 21 (182° ± 25°) to 42 IM (123° ± 47°) (p = 0.001), but was not different compared with control (155° ± 22°) (p = 0.108). Histologic evaluation showed morphologic changes in the anterior capsule (increased adhesions, myofibroblasts, thickness) and nonopposing joint surfaces (surface irregularities with tissue overgrowth, reduced matrix), but these changes did not increase with time. CONCLUSIONS: Overall, flexion-extension and pronation-supination exhibited distinct time-dependent patterns during contracture development and joint mobilization. Histologic evaluation showed tissue changes, but did not fully explain the patterns in contracture mechanics. Future work will use this rat model to evaluate the periarticular soft tissues of the elbow to isolate tissue-specific contributions to contracture to ultimately develop strategies for tissue-targeted treatments. CLINICAL RELEVANCE: A rat model of posttraumatic elbow contracture quantitatively described contracture development/progression and reiterates the need for rehabilitation strategies that consider both flexion-extension and pronation-supination elbow motion.

What Are the Effects of Capsular Plication on Translational Laxity of the Glenohumeral Joint: A Study in Cadaveric Shoulders.

BACKGROUND: Surgical treatment for shoulder instability generally involves labral repair with a capsular plication or imbrication. Good results are reported in both open and arthroscopic procedures, but there is no consensus on the amount or location of capsular plication that is needed to achieve stability and anatomic anterior, posterior, and inferior translation of the joint. QUESTIONS/PURPOSES: (1) What are the separate and combined effects of increasing plication magnitude and sequential additive plications in the anterior, posterior, and inferior locations of the joint capsule on glenohumeral joint translation in the anterior, posterior, and inferior directions? (2) What plication location and magnitude restores anterior, posterior, and inferior translation to a baseline level? METHODS: Fourteen cadaveric shoulders were dissected down to the glenohumeral capsule and underwent instrumented biomechanical testing. Each shoulder was loaded with 22 N in anterior, posterior, and inferior directions at 60° abduction and neutral rotation and flexion and the resulting translation were recorded. Testing was done over baseline (native), stretched (mechanically stretched capsule to imitate a lax capsule), and 5-mm, 10-mm, and 15-mm plication conditions. Individually, for each of the 5-, 10-, and 15-mm increments, plications were done in a fixed sequential order starting with anterior plication at the 3 o'clock position (Sequence I), then adding posterior plication at the 9 o'clock position (Sequence II), and then adding inferior plication at the 6 o'clock position (Sequence III). Each individual sequence was tested by placing 44 N (10 pounds) of manual force on the humerus directed in an anterior, posterior, and inferior direction to simulate clinical load and shift testing. The effect of plication magnitude and sequence on translation was tested with generalized estimating equation models. Translational differences between conditions were tested with paired t-tests. RESULTS: Translational laxity was highest with creation of the lax condition, as expected. Increasing plication magnitude had a significant effect on all three directions of translation. Plication location sequence had a significant effect on anterior and posterior translation. An interaction effect between plication magnitude and sequence was significant in anterior and posterior translation. Laxity in all directions was most restricted with 15-mm plication in anterior, posterior, and inferior locations. For anterior translational laxity, at 10-mm and 15-mm plication, there was a progressive decrease in translation magnitude (10-mm plication anterior only: 0.46 mm, plus posterior: 0.29 mm, plus inferior, -0.12 mm; and for 15-mm anterior only: -0.53 mm, plus posterior: -1.00 mm, plus inferior: -1.66 mm). For posterior translational laxity, 10-mm and 15-mm plication also showed progressive decrease in magnitude (10-mm plication anterior only: 0.46 mm, plus posterior: -0.25 mm, plus inferior: -1.94; and for 15-mm anterior only: 0.14 mm, plus posterior: -1.54 mm, plus inferior: -3.66). For inferior translational laxity, tightening was observed only with magnitude of plication (anterior only at 5 mm: 0.31 mm, at 10 mm: -1.39, at 15 mm: -3.61) but not with additional plication points (adding posterior and inferior sequences). To restore laxity closest to baseline, 10-mm AP/inferior plication best restored anterior translation, 15-mm anterior plication best restored posterior translation, and 5 mm posterior with or without inferior plication best restored inferior translation. CONCLUSIONS: Our results suggest that (1) a 10-mm plication in the anterior and posterior or anterior, posterior, and inferior positions may restore anterior translation closest to baseline; (2) 10-mm anterior and posterior or 15-mm anterior plications may restore posterior translation closest to baseline; and (3) 5-mm anterior and posterior or anterior, posterior, and inferior plications may restore inferior translation closest to baseline. Future studies using arthroscopic techniques for plication or open techniques via a true surgical approach might further characterize the effect of plication on glenohumeral translation. CLINICAL RELEVANCE: This study found that specific combinations of plication magnitude and location can be used to restore glenohumeral translation from a lax capsular state to a native state. This information can be used to guide surgical technique based on an individual patient's degree and direction of capsular laxity. In vivo testing of glenohumeral translation before and after capsular plication will be needed to validate these cadaveric results.

The Superior Glenohumeral Joint Capsule Alone Does Not Prevent Superior Translation of the Humeral Head: An In Vitro Biomechanical Study.

PURPOSE: To answer 2 questions: What is the main structure that prevents the superior translation of the humeral head, the supraspinatus or the superior capsule (SC)? And what mechanism does the principal structure rely on to prevent the superior translation of the humeral head, the spacer effect or the tensional hammock effect? METHODS: Eight shoulder specimens were assessed using a custom biomechanical testing system. Glenohumeral superior translation and subacromial peak pressure were compared using 6 models: the intact joint model, supraspinatus dysfunction model, supraspinatus defect model, SC tear model, SC defect model, and irreparable rotator cuff tear (IRCT) model. RESULTS: Compared with the intact joint model, the supraspinatus defect model significantly increased the superior translation (by 2.6 mm; P < .001) and subacromial peak pressure (by 0.43 MPa; P = .013) at 0° glenohumeral abduction, while the SC defect model unremarkably altered the superior translation at 0° (by 0.6 mm; P = .582) and 45° (by 0.3 mm; P = .867) of glenohumeral abduction and the subacromial peak pressure at 0° (by 0.11 MPa; P = .961), 30° (by -0.03 MPa; P = .997), and 45° (by -0.33 MPa; P = .485) of glenohumeral abduction. The supraspinatus dysfunction model significantly increased the superior translation at 0° (by 1.7 mm; P < .001), 30° (by 1.2 mm; P = .005), and 45° (by 0.8 mm; P = .026) of glenohumeral abduction, but not the subacromial peak pressure compared with the intact joint model. However, no significant differences were found between the supraspinatus defect model and the supraspinatus dysfunction model with respect to the superior translation or subacromial peak pressure (all P > .05). CONCLUSIONS: The anatomic SC has a negligible role in preventing the superior translation of the humeral head. CLINICAL RELEVANCE: SC reconstruction is not a simple anatomic reconstruction, and its promising clinical outcome may be due to tensional fixation technique and choice of graft.

The contribution of the posterolateral capsule to elbow joint stability: a cadaveric biomechanical investigation.

BACKGROUND: Elbow posterolateral rotatory instability occurs after an injury to the lateral collateral ligament complex (LCLC) in isolation or in association with an osteochondral fracture of the posterolateral margin of the capitellum (Osborne-Cotterill lesion [OCL]). The contribution to elbow stability of the posterolateral capsule, attached to this lesion, is unknown. This study quantified the displacement of the radial head on simulated posterior draw with sectioning of the posterior capsule (a simulated OCL) or LCLC. METHODS: Biomechanical testing of the elbow was performed in 8 upper limb cadavers. With the elbow 0°, 30°, 60°, and 90° degrees of flexion, posterior displacement of the radius was measured at increments of a load of 5 N up to 50 N. A simulated OCL and LCLC injury was then performed. RESULTS: A simulated OCL results in significantly more displacement of the radial head compared with the intact elbow at 30° to 60° of elbow flexion. LCLC resection confers significantly more displacement. An OCL after LCLC resection does not create further displacement. CONCLUSIONS: The degree of radial head displacement is greater after a simulated OCL at 30° to 60° of flexion compared with the intact elbow with the same load but not as great as seen with sectioning of the LCLC. This study suggests that the posterior capsule attaching to the back of the capitellum is important to elbow stability and should be identified as the Osborne-Cotterill ligament. Clinical studies are required to determine the importance of these biomechanical findings.

Stretching After Heat But Not After Cold Decreases Contractures After Spinal Cord Injury in Rats.

BACKGROUND: Contractures are a prevalent and potentially severe complication in patients with neurologic disorders. Although heat, cold, and stretching are commonly used for treatment of contractures and/or spasticity (the cause of many contractures), the sequential effects of these modalities remain unclear. QUESTIONS/PURPOSES: Using an established rat model with spinal cord injury with knee flexion contracture, we sought to determine what combination of heat or cold before stretching is the most effective for treatment of contractures derived from spastic paralyses and investigated which treatment leads to the best (1) improvement in the loss of ROM; (2) restoration of deterioration in the muscular and articular factors responsible for contractures; and (3) amelioration of histopathologic features such as muscular fibrosis in biceps femoris and shortening of the joint capsule. METHODS: Forty-two adolescent male Wistar rats were used. After spasticity developed at 2 weeks postinjury, each animal with spinal cord injury underwent the treatment protocol daily for 1 week. Knee extension ROM was measured with a goniometer by two examiners blinded to each other's scores. The muscular and articular factors contributing to contractures were calculated by measuring ROM before and after the myotomies. We quantitatively measured the muscular fibrosis and the synovial intima length, and observed the distribution of collagen of skeletal muscle. The results were confirmed by a blinded observer. RESULTS: The ROM of heat alone (34° ± 1°) and cold alone (34° ± 2°) rats were not different with the numbers available from that of rats with spinal cord injury (35° ± 2°) (p = 0.92 and 0.89, respectively). Stretching after heat (24° ± 1°) was more effective than stretching alone (27° ± 3°) at increasing ROM (p < 0.001). Contrastingly, there was no difference between stretching after cold (25° ± 1°) and stretching alone (p = 0.352). Stretching after heat was the most effective for percentage improvement of muscular (29%) and articular (50%) factors of contractures. Although quantification of muscular fibrosis in the rats with spinal cord injury (11% ± 1%) was higher than that of controls (9% ± 0.4%) (p = 0.01), no difference was found between spinal cord injury and each treatment protocol. The total synovial intima length of rats with spinal cord injury (5.9 ± 0.2 mm) became shorter than those of the controls (7.6 ± 0.2 mm) (p < 0.001), and those of stretching alone (6.9 ± 0.4 mm), stretching after heat (7.1 ± 0.3 mm), and stretching after cold (6.7 ± 0.4 mm) increased compared with rats with spinal cord injury (p = 0.01, p = 0.001, and p = 0.04, respectively). The staining intensity and pattern of collagen showed no difference among the treatment protocols. CONCLUSIONS: This animal study implies that heat or cold alone is ineffective, and that stretching is helpful for the correction of contractures after spinal cord injury. In addition, we provide evidence that heat is more beneficial than cold to increase the effectiveness of stretching. CLINICAL RELEVANCE: Our findings tend to support the idea that stretching after heat can improve the loss of ROM and histopathologic features of joint tissues. However, further studies are warranted to determine if our findings are clinically applicable.

Could Disruption of the Shoulder Superior Capsule Be the "Essential Lesion" of Rotator Cuff Disease? Possibly, but Questions Remain .

Rotator cuff disease remains a complex clinical problem with significant variation in pathology, clinical presentation, and management options. Functionally, humeral head depression is critical in restoring or maintaining arm elevation, and the shoulder superior capsule serves in this important function. Could disruption of the shoulder superior capsule be the "essential lesion" of rotator cuff disease? Possibly, but many questions remain unanswered, and substantial scientific evidence is required before we can assert with certainty that disruption of the superior capsule with resultant superior instability of the humeral head is the essential lesion of rotator cuff disease.

The Rotator Cuff and the Superior Capsule: Why We Need Both.

Tears of the rotator cuff are frequent. An estimated 250,000 to 500,000 repairs are performed annually in the United States. Rotator cuff repairs have been successful despite fatty infiltration and atrophy of the rotator cuff muscles. Although the emphasis in rotator cuff repair has historically focused on re-establishing the tendon attachment, there is growing interest in and understanding of the role of the superior capsule. The superior capsule is attached to the undersurface of the supraspinatus and infraspinatus muscle-tendon units, and it resists superior translation of the humeral head. Herein, we propose that it is the defect in the superior capsule that is the "essential lesion" in a superior rotator cuff tear, as opposed to the defect in the rotator cuff itself. We propose that rotator cuff repair must restore the normal capsular anatomy to provide normal biomechanics of the joint and thus a positive clinical outcome.

Biomechanical effects of anterior capsular plication and rotator interval closure in simulated anterior shoulder instability.

PURPOSE: The purpose of this study was to determine the effect of a stepwise arthroscopic anterior plication and arthroscopic-equivalent rotator interval (RI) closure on glenohumeral range of motion, kinematics, and translation in the setting of anterior instability. METHODS: Six cadaveric shoulders were stretched to 10 % beyond maximum external rotation (ER) to create an anterior shoulder instability model. Range of motion, kinematics, and glenohumeral translations were recorded for the following conditions: (1) intact, (2) stretched, (3) after anterior capsular plication, and (4) after RI closure. RESULTS: The total range of motion after capsular stretching increased significantly in the 60° abduction position (p = 0.037). Average ER and total rotation were significantly decreased from the intact and stretched conditions by both repair conditions at 60° and 0° of glenohumeral abduction (p < 0.05), with no significant difference between plication and additional RI closure. At 0° abduction and 0° ER, glenohumeral translation decreased significantly from the stretched condition after RI closure with 10 and 15 N anterior and 10 N posterior loads (p < 0.05). At 30° ER, translation after RI closure was significantly less than both the intact and stretched conditions with 10 N anterior loads (p = 0.009; p = 0.004). These changes in translational stability were not seen with plication alone. CONCLUSIONS: Anterior capsular plication reduced glenohumeral range of motion back to the intact state, and often tighter. RI closure did not contribute significantly to the reduction in the range of motion, but had implications regarding glenohumeral translation. Caution should be taken when performing anterior plication and combined repairs to avoid overtightening. Intraoperative translations could be useful when debating RI closure in patients with unidirectional anterior glenohumeral instability.

Effect of posterior shoulder tightness on internal impingement in a cadaveric model of throwing.

PURPOSE: Posterior shoulder tightness is common in throwing athletes, especially those with symptomatic shoulder internal impingement. The role of posteroinferior capsular contracture in the pathoetiologies of throwing-related injuries caused by shoulder internal impingement remains unclear. The purpose of this study was to assess effect of posterior shoulder tightness on internal impingement in a cadaveric model of throwing. METHODS: Seven fresh-frozen cadaveric shoulders were tested with the shoulder abducted to 90° and at maximum external rotation to simulate the late cocking phase of throwing motion. Glenohumeral joint contact pressure and area through internal impingement, humeral head shift, and the maximum humeral rotation angle were measured. Posteroinferior capsular plication was performed to simulate posteroinferior capsular tightness and induce glenohumeral internal rotation deficit. RESULTS: Following generation of simulated posteroinferior capsular tightness with resultant glenohumeral internal rotation deficit, glenohumeral contact pressure was significantly increased (P < 0.05), the impinged area of rotator cuff tendon was significantly decreased (P < 0.05), and the humeral head shifted posteriorly (P < 0.05) during shoulder internal impingement. CONCLUSION: Excessive posteroinferior capsular tightness can cause forceful internal impingement of the shoulder at maximum external rotation position.

Effectiveness of sustained stretching of the inferior capsule in the management of a frozen shoulder.

BACKGROUND: Physiotherapy treatment of frozen shoulder is varied, but most lack specific focus on the underlying disorder, which is the adhered shoulder capsule. Although positive effects were found after physiotherapy, the recurrence and prolonged disability of a frozen shoulder are major factors to focus on to provide the appropriate treatment. QUESTIONS/PURPOSES: We wished to study the effectiveness of a shoulder countertraction apparatus on ROM, pain, and function in patients with a frozen shoulder and compare their results with those of control subjects who received conventional physiotherapy. METHODS: A total of 100 participants were randomly assigned to an experimental group and a control group, with each group having 50 participants. The control group received physiotherapy and the experimental group received countertraction and physiotherapy. The total treatment time was 20 minutes a day for 5 days per week for 2 weeks. The outcome measures used were goniometer measurements, VAS, and the Oxford Shoulder Score. RESULTS: Improvements were seen in the scores for shoulder flexion (94.1° ± 19.79° at baseline increased to 161.9° ± 13.05° after intervention), abduction ROM (90.4° ± 21.18° at baseline increased to 154.8° ± 13.21° after intervention), and pain (8.00 ± 0.78 at baseline decreased to 3.48 ± 0.71 after intervention) in the experimental group. Sixty percent of the participants (n = 30) were improved to the fourth stage of satisfactory joint function according to the Oxford Shoulder Score in the experimental group compared with 18% (n = 9) in the control group (p < 0.001). CONCLUSIONS: Incorporating shoulder countertraction along with physiotherapy improves shoulder function compared with physiotherapy alone for the treatment of a frozen shoulder. Additional studies are needed focusing on this concept to increase the generalizability of the counter-traction apparatus in various groups. LEVEL OF EVIDENCE: Level II, prospective comparative study. See the Instructions for Authors for a complete description of levels of evidence.

Total dorsal capsulectomy for the treatment of mucous cysts.

PURPOSE: To describe the technique of total dorsal capsulectomy alone for mucous cysts of the distal interphalangeal (DIP) joint and evaluate its outcomes and complications. METHODS: Nineteen patients (18 women and 1 man) with 19 mucous cysts were treated by a total dorsal capsulectomy without cyst excision or osteophyte removal. The average age at surgery was 63 years. The thumb was involved in 4 patients, index finger in 1, middle finger in 7, ring finger in 4, and little finger in 3. Twelve patients had nail deformities associated with the mucous cyst. The average period of postoperative follow-up was 26 months. The dorsal half of the DIP joint capsule was resected with a punch and curette. The cyst and osteophytes were left intact. RESULTS: The average preoperative range of motion for the DIP joint was from 10° of extension to 45° of flexion. Radiographs showed osteophytes at the DIP joint in all affected digits. After surgery, all cysts disappeared at an average of 3 weeks. There was no recurrence at the time of final follow-up. All nail deformities had resolved at an average of 5 months after surgery. The average motion for the DIP joint at the time of final follow-up was from 8° of extension to 56° of flexion. There were no acquired nail deformities or other complications. CONCLUSIONS: A total dorsal capsulectomy alone was a simple treatment for mucous cysts and did not lead to any recurrence. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Role of the superior shoulder capsule in passive stability of the glenohumeral joint.

BACKGROUND: The shoulder capsule is the main static stabilizer of the glenohumeral joint. However, few studies specifically address the function of the superior shoulder capsule, which is usually damaged in patients with complete rotator cuff tears. Therefore, the purpose of this study was to determine the biomechanical contribution of the superior shoulder capsule to passive stability of the glenohumeral joint. METHODS: Seven cadaveric shoulders were tested with a custom testing system. Glenohumeral translations, subacromial contact pressure, and glenohumeral external and internal rotations were quantified at 5°, 30°, and 60° of glenohumeral abduction. Data were compared among 3 conditions: (1) intact superior capsule, (2) after detaching the superior capsule from the greater tuberosity (tear model), and (3) after complete removal of the superior capsule from the greater tuberosity to the superior glenoid (defect model). RESULTS: A tear of the superior capsule significantly (P < .05) increased anterior and inferior translations compared with those in the intact capsule. Creation of a superior capsular defect significantly (P < .05) increased glenohumeral translation in all directions, subacromial contact pressure at 30° of glenohumeral abduction, and external and internal rotations compared with those of the intact capsule. CONCLUSION: The superior shoulder capsule plays an important role in passive stability of the glenohumeral joint. A tear in the superior capsule at the greater tuberosity, which may be seen with partial rotator cuff tears, increased anterior and inferior translations. A defect in the superior capsule, seen in massive cuff tears, increased glenohumeral translations in all directions.

The extensor hallucis capsularis tendon--a prospective study of its occurrence and function.

BACKGROUND: There is inhomogeneous data about the hallucal extensor apparatus and the occurrence of accessory tendon slips and their function. We performed this study to clarify its anatomical features and make conclusions about its function. METHODS: Investigations were performed prospectively during operative correction of severe hallux valgus and interphalangeus in 60 consecutive cases. The occurrence, topographic location and size of accessory extensor tendons as well as the insertion patterns were recorded. After dissection traction of the accessory tendon was carried out to gain information about its function. RESULTS: In contradiction to previous studies reporting numerous variations in the distal attachments of the hallucal extensor apparatus with different accessory tendons described, our investigations showed constant anatomical features. In all but one case (98.3%) there was an accessory medial extensor hallucis longus tendon adjacent to the main tendon, always inserting on the dorsomedial aspect of the metatarsophalangeal joint capsule. We therefore chose the terminology extensor hallucis capsularis (EHC) used in previous studies. The intraoperative testing of the tendon showed it to exert a pretension of the metatarsophalangeal (MTP) joint capsule. CONCLUSION: Our study showed consistent anatomical features with an occurrence of the EHC tendon in 98.3%. We determined that its function is to pretension the MTP joint capsule, therefore avoiding capsular impingement during hallucal extension. The high incidence of the EHC tendon in our study may also postulate a correlation with MTP joint deformities and further cadaveric studies will be necessary to evaluate a possible predisposition for hallux valgus genesis.