Improved Outside-In Suture through the Joint Capsule to Repair the Palmer I-B Triangular Fibrocartilage Complex Superficial Injury.

BACKGROUND: The treatment of type I-B triangular fibrocartilage complex superficial injury is always a challenge to orthopedists. The traditional outside-in suture method often causes a risk of nervous irritation. We designed a modified outside-in suture through the joint capsule to repair the Palmer I-B triangular fibrocartilage complex superficial injury. METHODS: From December 2014 to December 2018, we retrospectively collected the medical records of 18 patients in our hospital who used the modified outside-in suture through the joint capsule to repair type I-B triangular fibrocartilage complex superficial injury. Among them, there were 12 males and 6 females, with an average age of 36.2 years. There were 6 cases on the left side and 12 cases on the right side. Record the healing time of all patients after surgery and the occurrence of related complications, and record the pain visual analogue scale (VAS), grip strength, wrist flexion and extension, radioulnar deviation and forearm rotation range of motion, modified Mayo wrist joint function score, and disability of arm-shoulder-hand (DASH) score before operation and at the last follow-up. RESULTS: One patient was lost to follow-up, and a total of 17 patients received the final follow-up. Patients were followed up for 24 to 36 months, with an average of 29.6 ± 3.0 months. No wound infection, nerve damage, or irritation occurred after the operation. At the last follow-up, 15 cases of wrist pain disappeared completely, and 2 cases had mild discomfort during exercise. At the last follow-up, VAS decreased from 3.8 ± 0.7 points before operation to 0.8 ± 0.7 points (P < 0.05); grip strength increased from 15.1 ± 3.1 kg before operation to 23.2 ± 1.5 kg (P < 0.05); wrist flexion and extension, radioulnar deflection, and forearm rotational mobility increased from 116.3 ± 2.2°, 37.0 ± 3.5°, and 141.6 ± 2.2° before operation to 117.2 ± 2.5° (P < 0.05), 38.9 ± 3.0° (P < 0.05), and 142.4 ± 1.9° (P < 0.05), respectively; the modified Mayo wrist joint function score increased from 66.1 ± 3.6 points to 82.5 ± 3.9 points (P < 0.05), of which 10 cases were excellent, 5 cases were good, 2 cases were fair, and the excellent and good rate was 88.2%; DASH score improved from 37.0 ± 5.7 points preoperatively to 8.0 ± 2.5 points (P < 0.05). CONCLUSION: The modified outside-in suture through the joint capsule to repair the superficial injury of Palmer I-B triangular fibrocartilage complex has a good clinical effect and is worthy of clinical widespread promotion.

Mechanisms of reducing joint stiffness by blocking collagen fibrillogenesis in a rabbit model of posttraumatic arthrofibrosis.

Posttraumatic fibrotic scarring is a significant medical problem that alters the proper functioning of injured tissues. Current methods to reduce posttraumatic fibrosis rely on anti-inflammatory and anti-proliferative agents with broad intracellular targets. As a result, their use is not fully effective and may cause unwanted side effects. Our group previously demonstrated that extracellular collagen fibrillogenesis is a valid and specific target to reduce collagen-rich scar buildup. Our previous studies showed that a rationally designed antibody that binds the C-terminal telopeptide of the α2(I) chain involved in the aggregation of collagen molecules limits fibril assembly in vitro and reduces scar formation in vivo. Here, we have utilized a clinically relevant arthrofibrosis model to study the broad mechanisms of the anti-scarring activity of this antibody. Moreover, we analyzed the effects of targeting collagen fibril formation on the quality of healed joint tissues, including the posterior capsule, patellar tendon, and subchondral bone. Our results show that blocking collagen fibrillogenesis not only reduces collagen content in the scar, but also accelerates the remodeling of healing tissues and changes the collagen fibrils' cross-linking. In total, this study demonstrated that targeting collagen fibrillogenesis to limit arthrofibrosis affects neither the quality of healing of the joint tissues nor disturbs vital tissues and organs.

Acupotomy treatment for finger joint contracture after immobilization: Case report.

INTRODUCTION: Contractures frequently occur in the finger joints after immobilization. This report describes the effect of acupotomy treatment in patients with joint contracture due to immobilization of the finger joints. PATIENT CONCERNS AND CLINICAL FINDINGS: Case 1 was of a 39-year-old male patient who had flexion limitation of the left thumb and difficulty in grasping. Case 2 was of a 41-year-old female patient who had flexion limitation of the right index finger and difficulty in typing. Stiffness occurred after tendon repair surgery and cast immobilization in both cases. In Case 1, the patient had limited flexion movement of the first metacarpophalangeal and interphalangeal joints after 5 weeks of immobilization of the left thumb in a cast. In Case 2, the patient had limited flexion movement after 3 weeks of immobilization of the second proximal interphalangeal joint of the left hand in a cast. DIAGNOSIS, INTERVENTIONS, AND OUTCOMES: We diagnosed both patients with finger joint contracture due to immobilization. Conservative treatment for approximately 4 weeks did not lead to improvement in either patient. Acupotomy is the key treatment for improving movement in Korean Medicine. Therefore, acupotomy was performed, and joint stiffness markedly improved without adverse events. Both patients reported that the daily use of the damaged fingers became comfortable. CONCLUSION: We found that acupotomy may be effective for finger joint contracture due to improper immobilization. We suggest it as a simple and safe treatment for joint contracture.

Capsular Management Techniques and Hip Arthroscopy.

There has been an increased emphasis on capsular management during hip arthroscopy in the literature in recent years. The capsule plays a significant role in the hip joint stability and studies have demonstrated that capsular closure can restore the biomechanics of the hip back to the native state. Capsular management also affects functional outcomes with capsular repair resulting in better clinical outcomes in some studies. Management of the capsule has evolved in recent years with more surgeons performing routine capsular closure. Management techniques and degree of capsular closure, however, can be quite variable between surgeons. This review will discuss hip capsular anatomy, the importance of the capsule in hip biomechanics, management of the capsule during arthroscopy, and functional outcomes as it relates to the various capsular closure techniques versus leaving the capsulotomy unrepaired.

Simulating the effect of glenohumeral capsulorrhaphy on kinematics and muscle function.

This study aimed to use a predictive simulation framework to examine shoulder kinematics, muscular effort, and task performance during functional upper limb movements under simulated selective glenohumeral capsulorrhaphy. A musculoskeletal model of the torso and upper limb was adapted to include passive restraints that simulated the changes in shoulder range of motion stemming from selective glenohumeral capsulorrhaphy procedures (anteroinferior, anterosuperior, posteroinferior, posterosuperior, and total anterior, inferior, posterior, and superior). Predictive muscle-driven simulations of three functional movements (upward reach, forward reach, and head touch) were generated with each model. Shoulder kinematics (elevation, elevation plane, and axial rotation), muscle cost (i.e., muscular effort), and task performance time were compared to a baseline model to assess the impact of the capsulorrhaphy procedures. Minimal differences in shoulder kinematics and task performance times were observed, suggesting that task performance could be maintained across the capsulorrhaphy conditions. Increased muscle cost was observed under the selective capsulorrhaphy conditions, however this was dependent on the task and capsulorrhaphy condition. Larger increases in muscle cost were observed under the capsulorrhaphy conditions that incurred the greatest reductions in shoulder range of motion (i.e., total inferior, total anterior, anteroinferior, and total posterior conditions) and during tasks that required shoulder kinematics closer to end range of motion (i.e., upward reach and head touch). The elevated muscle loading observed could present a risk to joint capsule repair. Appropriate rehabilitation following glenohumeral capsulorrhaphy is required to account for the elevated demands placed on muscles, particularly when a significant range of motion loss presents.

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.

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.

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.

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.

Shoulder adhesive capsulitis: diagnostic value of active and passive range of motion with volume of gleno-humeral capsule as a reference.

BACKGROUND: The diagnosis of adhesive capsulitis is currently based on restricted range of motion (ROM) but its diagnostic value has only been rarely investigated. AIM: The aim of this study is to assess the diagnostic value of active global and passive gleno-humeral ROM to diagnose shoulder adhesive capsulitis. DESIGN: Cross-sectional descriptive study. SETTING: One French center for Rehabilitation Medicine. POPULATION: Patients referred for treatment of shoulder adhesive capsulitis in our center were included. Inclusion criteria were: shoulder pain; limitation of active global ROM (abduction or flexion <180°); limitation of passive gleno-humeral ROM (abduction or flexion <90° or 25% reduction at less of lateral rotation versus the opposite shoulder); no gleno-humeral arthropathy on radiography. METHODS: The volume of the gleno-humeral capsule was assessed during a procedure of arthro-distension. The reference criterion for adhesive capsulitis was a volume <12 mL. We analyzed the correlation between the parameters of mobility and the volume of the gleno-humeral capsule; and the positive predictive value (PPV) of inclusion criteria, with the reference criterion for the diagnosis of adhesive capsulitis. RESULTS: We included 38 patients. Passive gleno-humeral ROM in abduction only was correlated with volume of the gleno-humeral capsule: r=0.33, P=0.043. The PPV of inclusion criteria was 82% for the diagnosis of shoulder adhesive capsulitis. Rather than 90°, when we considered 80°, 60° and 40° as the threshold of passive gleno-humeral ROM in abduction, the PPV increased from 83% to 100%. CONCLUSIONS: Passive gleno-humeral ROM in abduction is correlated with volume of the gleno-humeral capsule. The PPV is high for active global and passive gleno-humeral ROM for diagnosis of shoulder adhesive capsulitis. CLINICAL REHABILITATION IMPACT: Limitation of active and passive shoulder ROM, especially passive abduction gleno-humeral, is a good criterion to diagnose shoulder adhesive capsulitis, in patients with shoulder pain and no gleno-humeral arthropathy on radiography.

[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.

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.

Hip capsule biomechanics after arthroplasty: the effect of implant, approach, and surgical repair.

AIMS: The hip's capsular ligaments passively restrain extreme range of movement (ROM) by wrapping around the native femoral head/neck. We determined the effect of hip resurfacing arthroplasty (HRA), dual-mobility total hip arthroplasty (DM-THA), conventional THA, and surgical approach on ligament function. MATERIALS AND METHODS: Eight paired cadaveric hip joints were skeletonized but retained the hip capsule. Capsular ROM restraint during controlled internal rotation (IR) and external rotation (ER) was measured before and after HRA, DM-THA, and conventional THA, with a posterior (right hips) and anterior capsulotomy (left hips). RESULTS: Hip resurfacing provided a near-native ROM with between 5° to 17° increase in IR/ER ROM compared with the native hip for the different positions tested, which was a 9% to 33% increase. DM-THA generated a 9° to 61° (18% to 121%) increase in ROM. Conventional THA generated a 52° to 100° (94% to 199%) increase in ROM. Thus, for conventional THA, the capsule function that exerts a limit on ROM is lost. It is restored to some extent by DM-THA, and almost fully restored by hip resurfacing. In positions of low flexion/extension, the posterior capsulotomy provided more normal function than the anterior, possibly because the capsule was shortened during posterior repair. However, in deep flexion positions, the anterior capsulotomy functioned better. CONCLUSION: Native head-size and capsular repair preserves capsular function after arthroplasty. The anterior and posterior approach differentially affect postoperative biomechanical function of the capsular ligaments. Cite this article: Bone Joint J 2019;101-B:426-434.

The Influence of Glenohumeral Joint Posterior Capsule Tightness and Impingement Symptoms on Shoulder Impairments and Kinematics.

BACKGROUND: Posterior capsule tightness (PCT) and shoulder impingement syndrome (SIS) symptoms are both associated with altered shoulder biomechanics and impairments. However, their combined effect on kinematics, pain, range of motion (ROM), strength, and function remain unknown. OBJECTIVE: The purpose of this study was to determine if the combination of PCT and SIS affects scapular and humeral kinematics, glenohumeral joint ROM, glenohumeral joint external rotation strength, pain, and function differently than does either factor (PCT or SIS) alone. DESIGN: The design was a cross-sectional group comparison. METHODS: Participants were placed into 1 of 4 groups based on the presence or absence of SIS and PCT: control group (n = 28), PCT group (n = 27), SIS group (n = 25), and SIS + PCT group (n = 25). Scapular kinematics and humeral translations were quantified with an electromagnetic motion capture system. Shoulder internal rotation and external rotation ROM, external rotation strength, and pain and Shoulder Pain and Disabilities Index scores were compared between groups with ANOVA. RESULTS: The SIS group had greater scapular internal rotation (mean difference = 5.13°; 95% confidence interval [CI] = 1.53°-8.9°) and less humeral anterior translation (1.71 mm; 95% CI = 0.53-2.9 mm) than the other groups. Groups without PCT had greater internal rotation ROM (16.05°; 95% CI = 5.09°-28.28°). The SIS + PCT group had lower pain thresholds at the levator scapulae muscle (108.02 kPa; 95% CI = 30.15-185.88 kPa) and the highest Shoulder Pain and Disabilities Index score (∼ 44.52; 95% CI = 33.41-55.63). LIMITATIONS: These results may be limited to individuals with impingement symptoms and cannot be generalized to other shoulder conditions. CONCLUSIONS: Decreased ROM and lower pain thresholds were found in individuals with both impingement symptoms and PCT. However, the combination of factors did not influence scapular and humeral kinematics.

The Role of Anterior Capsular Laxity in Hip Microinstability: A Novel Biomechanical Model.

BACKGROUND: Hip microinstability is an increasingly recognized source of hip pain and disability. Although the clinical entity has been well described, the pathomechanics of this disease remain poorly understood. PURPOSE/HYPOTHESIS: The purpose of this study was to determine the role of capsular laxity in atraumatic hip microinstability. Our hypothesis was that cyclic stretching of the anterior hip capsule would result in increased hip range of motion and femoral head displacement. STUDY DESIGN: Controlled laboratory study. METHODS: In this study, 7 hip specimens met inclusion criteria (age, 18-46 years). Specimens were stripped of all soft tissue, aligned, cut, and potted by use of a custom jig. A materials testing system was used to cyclically stretch the anterior hip capsule in extension and external rotation while rotating about the mechanical axis of the hip. A motion tracking system was used to record hip rotation and displacement of the femoral head relative to the acetabulum in the anterior-posterior, medial-lateral, and superior-inferior directions. Testing was conducted at baseline, after venting, and after capsular stretching. RESULTS: With the hip in anatomic neutral alignment, cyclic stretching of the anterior hip capsule resulted in increased hip rotation ( P < .001). Femoral head displacement significantly increased relative to the vented state in the medial-lateral ( P < .001), anterior-posterior ( P = .013), and superior-inferior ( P = .036) planes after cyclic stretching of the anterior hip capsule. CONCLUSION: The anterior hip capsule plays an important role in controlling hip rotation and femoral head displacement. This study is the first to display significant increases in femoral head displacement through a controlled cyclic stretching protocol of the anterior hip capsule. CLINICAL RELEVANCE: This study is directly applicable to the treatment of atraumatic hip microinstability. The results quantitatively define the relative importance of the hip capsule in controlling femoral head motion. This allows for a better understanding of the pathophysiological process of hip microinstability and serves as a platform to develop effective surgical techniques for treatment of this disease.

Hip Joint Torsional Loading Before and After Cam Femoroacetabular Impingement Surgery.

BACKGROUND: Surgical management of cam femoroacetabular impingement (FAI) aims to preserve the native hip and restore joint function, although it is unclear how the capsulotomy, cam deformity, and capsular repair influence joint mechanics to balance functional mobility. PURPOSE: To examine the contributions of the capsule and cam deformity to hip joint mechanics. Using in vitro, cadaveric methods, we examined the individual effects of the surgical capsulotomy, cam resection, and capsular repair on passive range of motion and resistance of applied torque. STUDY DESIGN: Descriptive laboratory study. METHODS: Twelve cadaveric hips with cam deformities were skeletonized to the capsule and mounted onto a robotic testing platform. The robot positioned each intact hip in multiple testing positions: (1) extension, (2) neutral 0°, (3) flexion 30°, (4) flexion 90°, (5) flexion-adduction and internal rotation (FADIR), and (6) flexion-abduction and external rotation. Then the robot performed applicable internal and external rotations, recording the neutral path of motion until a 5-N·m of torque was reached in each rotational direction. Each hip then underwent a series of surgical stages (T-capsulotomy, cam resection, capsular repair) and was retested to reach 5 N·m of internal and external torque again after each stage. During the capsulotomy and cam resection stages, the initial intact hip's recorded path of motion was replayed to measure changes in resisted torque. RESULTS: Regarding changes in motion, external rotation increased substantially after capsulotomies, but internal rotation only further increased at flexion 90° (change +32%, P = .001, d = 0.58) and FADIR (change +33%, P < .001, d = 0.51) after cam resections. Capsular repair provided marginal restraint for internal rotation but restrained the external rotation compared with the capsulotomy stage. Regarding changes in torque, both internal and external torque resistance decreased after capsulotomy. Compared with the capsulotomy stage, cam resection further reduced internal torque resistance during flexion 90° (change -45%, P < .001, d = 0.98) and FADIR (change -37%, P = .003, d = 1.0), where the cam deformity accounted for 21% of the intact hip's torsional resistance in flexion 90° and 27% in FADIR. CONCLUSION: Although the capsule played a predominant role in joint constraint, the cam deformity provided 21% to 27% of the intact hip's resistance to torsional load in flexion and internal rotation. Resecting the cam deformity would remove this loading on the chondrolabral junction. CLINICAL RELEVANCE: These findings are the first to quantify the contribution of the cam deformity to resisting hip joint torsional loads and thus quantify the reduced loading on the chondrolabral complex that can be achieved after cam resection.

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.

Effects of Capsular Reconstruction With an Iliotibial Band Allograft on Distractive Stability of the Hip Joint: A Biomechanical Study.

BACKGROUND: The capsular ligaments and the labral suction seal cooperatively manage distractive stability of the hip. Capsular reconstruction using an iliotibial band (ITB) allograft aims to address capsular insufficiency and iatrogenic instability. However, the extent to which this procedure may restore hip distractive stability after a capsular defect is unknown. PURPOSE: To evaluate the biomechanical effects of capsular reconstruction on distractive stability of the hip joint. STUDY DESIGN: Controlled laboratory study. METHODS: Eight fresh-frozen cadaveric hip specimens were dissected to the level of the capsule and axially distracted in 3 testing states: intact capsule, partial capsular defect, and capsular reconstruction with an ITB allograft. Each femur was compressed with 500 N of force and then distracted 6 mm relative to the neutral position at 0.5 mm/s. Distractive force was continuously recorded, and the first peak delineating 2 phases of hip distractive stability in the force-displacement curve was analyzed. RESULTS: The median force at maximum distraction in the capsular reconstruction state (156 N) was significantly greater than that in the capsular defect state (89 N; P = .036) but not significantly different from that in the intact state (218 N; P = .054). Median values for distractive force at first peak (60 N, 72 N, and 61 N, respectively; P = .607), distraction at first peak (2.3 mm, 2.3 mm, and 2.5 mm, respectively; P = .846), and percentage decrease in distractive force (35%, 78%, and 63%, respectively; P = .072) after the first peak were not significantly different between the intact, defect, and reconstruction states. CONCLUSION: Capsular reconstruction with an ITB allograft significantly increased the force required to distract the hip compared with a capsular defect in a cadaveric model. To our knowledge, this is the first study to report an initial peak distractive force and to propose 2 distinct phases of hip distractive stability. CLINICAL RELEVANCE: The consequences of a capsular defect on distractive stability of the hip may be underappreciated among the orthopaedic community; with that said, capsular reconstruction using an ITB allograft provided significantly increased distractive stability and should be considered an effective treatment option for patients with symptomatic capsular deficiency.

The influence of posterior glenohumeral joint capsule tightness and humeral retroversion on clinical measurements.

OBJECTIVES: To assess the influence of posterior capsule tightness and humeral retroversion on shoulder motion measurements. DESIGN: Cross-Sectional study. SETTING: Controlled university laboratory. PARTICIPANTS: 75 asymptomatic individuals were assigned to one of 4 groups: control (n = 28); posterior capsule tightness only (n = 17); humeral retroversion only (n = 15); and combined posterior capsule tightness and retroversion (n = 15). MAIN OUTCOME MEASURES: Six clinical measurements were compared across groups: bicipital forearm angle, low flexion, glenohumeral internal and external rotation, horizontal adduction and extension with internal rotation. RESULTS: The group with both adaptations had decreased internal rotation compared to the control and retroversion only groups, as well as increased external rotation compared to the control and posterior capsule only groups. There were no between group differences for the horizontal adduction or extension with internal rotation measurements. The retroversion only and combined groups showed decreased bicipital forearm angle compared with the control and posterior tightness groups. The posterior capsule tightness and combined groups demonstrated decreased low flexion compared to the other groups. CONCLUSION: The combination of osseous and soft tissue adaptions alter shoulder motion measures more than a single adaption, making a comprehensive clinical assessment vital when managing individuals with shoulder pain.

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.