Assessment of rotator cuff repair integrity using ultrasound and magnetic resonance imaging in a multicenter study.

BACKGROUND: This study compared ultrasound and magnetic resonance imaging (MRI) evaluation of the repaired rotator cuff to determine concordance between these imaging studies. METHODS: We performed a concordance study using the data from a prospective nonrandomized multicenter study at 13 centers. A suture bridge technique was used to repair 113 rotator cuff tears that were between 1 and 4 cm wide. Repairs were evaluated with MRI and ultrasound at multiple time points after surgery. The MRI scans were read by a central radiologist and the surgeon, and the ultrasounds were read by a local radiologist or the surgeon who performed the ultrasound. RESULTS: The concordance between the central radiologist's MRI reading and the investigator's MRI readings at all time points was 89%, with a κ coefficient of 0.60. The concordance between the central radiologist's MRI and ultrasound readings at all time points was 85%, with a κ coefficient of 0.40. The concordance between the investigator's MRI and ultrasound readings was 92%, with a κ coefficient of 0.70. CONCLUSIONS: In the community setting, ultrasound may be used to evaluate the integrity of a repaired rotator cuff tendon and constitutes a comparable alternative to MRI when evaluating the integrity of a rotator cuff repair. Clinical investigators should compare their postoperative ultrasound results with their postoperative MRI results for a certain time period to establish the accuracy of ultrasound before relying solely on ultrasound imaging to evaluate the integrity of their rotator cuff repairs.

The effect of screw position on the initial fixation of a reverse total shoulder prosthesis in a glenoid with a cavitary bone defect.

Patients with rotator cuff tear arthropathy can be treated successfully with a reverse total shoulder prosthesis. In patients with significant glenoid bone loss, achieving stable bone fixation can be challenging, as the surgeon must know when bone grafting is necessary and when the plan to implant the reverse total shoulder prosthesis should be abandoned because of the likelihood of early implant loosening. The purposes of this study were (1) to determine the initial stability of a metal glenoid implant fixed in a glenoid with a central cavitary defect and (2) to determine whether an altered screw configuration would sufficiently resist implant micromotion and, thereby, allow bone ingrowth to occur. The Delta III reverse total shoulder glenoid implant was fixed into foam scapulae with a uniform density similar to normal glenoid bone density. The control group implants were fixed into foam scapulae without a glenoid defect, by use of the standard surgical technique for screw placement. The second group was fixed into foam scapulae containing a central cavitary glenoid defect, by use of the standard surgical technique for screw placement. The central cavitary defect was meant to simulate the bone loss typically found after the removal of a loose pegged glenoid implant, and it was created with a 4-pegged glenoid drill guide. A third group was fixed into foam scapula with a central cavitary glenoid defect, with an experimental screw configuration by use of a posterior screw directed toward the spine of the scapula and an anterior screw directed inferior to the central peg. All specimens were loaded with 500 cycles of 1 body weight (70 kg) to simulate the forces generated during arm elevation that occur during the first 3 months after surgery. Micromotion between the implant and the foam bone was measured with a digital video motion analysis system (accuracy, +/- 2.6 microm). After loading of the implant with 70 kg for 500 cycles in the superior direction, the mean micromotion was 54 microm (SD, 22) in the control group, 159 microm (SD, 70) in the second group, and 86 microm (SD, 32) in the third group (P = 0.003). Fixing the posterior screw into the spine of the scapula and directing the anterior screw below the central peg decreased the micromotion of a metal glenoid implant fixed in a glenoid with a cavitary defect by 46% and, more importantly, reduced the micromotion below the critical threshold of 150 microm, which is necessary for bone ingrowth and long-term survival of the implant.

Inter-rater reliability of an arthritic glenoid morphology classification system.

To our knowledge, no independent analysis of the inter-rater agreement of the widely used Walch classification for osteoarthritic glenoid morphology has been performed. The computed tomography scans of 24 shoulders with primary osteoarthritis were used by 4 experienced shoulder surgeons to classify the glenoids independently according to Walch et al. The weighted kappa statistic was calculated to determine the inter-rater and intrarater agreement among observers. The overall inter-rater agreement for the Walch classification was fair (kappa = 0.37) when classified into the 5 types (A1, A2, B1, B2, and C). Agreement for the various subclassifications was as follows: A1, kappa = 0.22; A2, kappa = 0.33; B1, kappa = 0.17; B2, kappa = 0.32; and C, kappa = 0.86. When the classification system was simplified to just the 3 major types (A, B, and C), overall agreement was moderate (kappa = 0.44). Agreement for each type was moderate for A (kappa = 0.59) and B (kappa = 0.59) and almost perfect for C (kappa = 0.89). Overall intrarater agreement was fair (kappa = 0.37). We conclude that only fair agreement was found among experienced shoulder surgeons when classifying arthritic shoulders using the classification system of Walch et al. A glenoid classification scheme that relies more upon glenoid morphology and less upon humeral head position may demonstrate greater observer agreement and, therefore, may offer greater value.

The three-dimensional glenoid vault model can estimate normal glenoid version in osteoarthritis.

Glenohumeral arthroplasty can involve correcting pathologic glenoid tilt or version. Predicting the physiologic glenoid version for a particular individual can be difficult. We propose using a previously validated, 3-dimensional, glenoid vault model as a template to predict normal glenoid version. Computed tomography scans of both shoulders were obtained in 14 subjects with unilateral glenohumeral osteoarthritis. Custom-developed graphic software was used to create a 3-D reconstruction of each scapula. Within the software, the vault model was placed in a best-fit orientation into each glenoid vault independently by 3 observers who were blinded to the contralateral scapula. Measurement differences between the glenoid and vault model were analyzed by repeated-measures analysis of variance. Standard errors of measurement (SEM) were calculated. Interobserver and intraobserver reliabilities were assessed. The healthy glenoid version averaged -7.0 degrees (SEM, 0.7 degrees ; range, 0 degrees to -14 degrees ). The arthritic glenoid version averaged -15.6 degrees (SEM, 0.7 degrees ; range, 1 degrees to -33 degrees ; P < .0001). The version of the implanted vault model measured -7.1 degrees (SEM, 0.7 degrees ; range, -1 degrees to -15 degrees ) on the healthy side and -7.2 degrees (SEM, 0.7 degrees ; range -2 degrees to -11 degrees ) on the arthritic side. Measurements between observers were not significantly different (P = .98). Interobserver and intraobserver correlation coefficients were 0.79 (P < .001) and 0.80 (P < .001). In the arthritic glenoid, the vault model reproducibly closely approximated the version of the normal contralateral glenoid, -7.2 degrees vs -7.0 degrees (P = .99) and is a novel and accurate method of estimating the normal glenoid version. This technique may be valuable in correcting pathologic glenoid version due to arthritis.

Normal glenoid vault anatomy and validation of a novel glenoid implant shape.

Current glenoid implants are designed to be secured to the articular surface. When the articular surface is compromised, a glenoid component could be implanted if it obtained fixation from the endosteal surface of the glenoid vault. The first step for designing such a glenoid implant is to define the normal three-dimensional anatomy of the glenoid vault. The purpose of this study was to define the variations in glenoid vault shape in a large group of cadaver scapula. Computed tomographic (CT) scans of 61 normal scapulae (mean, 25-34 years) from the Haman-Todd Osteological Collection, with a wide range of sizes, were examined to define the normal glenoid vault anatomy. A custom software program was used to manipulate and measure the scans to determine the morphologic variations among the different glenoid vaults. From these data, we defined a unique glenoid vault shape and empirically developed 5 sizes to represent the study population of the 61 scapulae. A second group of 11 cadaver scapulae were used to validate the shape defined using the other 61. Prototype implants were placed into the real 11 scapulae using standard surgical techniques and then CT-scanned to analyze the shape of the glenoid vault. In the 61 scapulae, 85% of the points defining the endosteal surfaces vary among scapulae by less than 2 mm. For each of the 11 cadaver scapulae, the implant size used in the virtual computer implantation was the same size used for the plastic components placed into the cadaver scapulae. Fifty percent of the measured distances between the outer dimensions of the plastic models was within 2.4 mm of the glenoid endosteal surface. Eighty percent of the surface area of the plastic models was within 3.1 mm of the glenoid endosteal surface. Five percent of the dimensions were less than 1 mm and were considered to be areas of point contact. Before designing implants that can be used in pathologic glenoids, the shape of the normal glenoid vault must first be defined. This study defined a normal glenoid vault shape that can accommodate different sized scapula with 5 sizes. This glenoid shape may be used as a template to design a glenoid implant that obtains fixation within the glenoid vault.

Latissimus dorsi tendon transfer for irreparable posterosuperior rotator cuff tears. Surgical technique.

BACKGROUND: The purpose of this study was to evaluate the clinical results of latissimus dorsi tendon transfer in patients with an irreparable posterosuperior rotator cuff tear to help determine which patient and anatomic factors affect clinical outcome. METHODS: Fourteen patients with a latissimus dorsi tendon transfer were clinically evaluated with use of the PENN (University of Pennsylvania) shoulder score as well as with quantitative measurement of isometric muscle strength and the range of motion of both shoulders at a minimum of twenty-four months postoperatively. The anatomic results were evaluated with postoperative magnetic resonance imaging and electromyography. RESULTS: Nine patients were satisfied with the outcome, had significant clinical improvement, and reported that they would have the operation again under similar circumstances. The other five patients were dissatisfied with the result and had significantly worse PENN scores, active elevation, and objective measures of strength. Eight of the nine patients with a good clinical result were male, and four of the five with a poor result were female. Patients with a good clinical result had had significantly better preoperative function in active forward flexion and active external rotation compared with the patients with a poor result. The magnetic resonance imaging demonstrated healing of the tendon to the greater tuberosity in twelve patients and equivocal healing in two. There was no significant atrophy of any of the transferred muscles. Electromyography demonstrated clear activity in the transferred latissimus muscle during humeral adduction in all fourteen patients, some electrical activity with active forward elevation in only one patient, and some electrical activity with active external rotation in six of the nine patients with a good clinical result. None of the patients with a poor clinical result demonstrated electrical activity of the transferred muscle with active forward flexion or external rotation. CONCLUSIONS: Synchronous in-phase contraction of the transferred latissimus dorsi is a variable finding following the surgical treatment of irreparable posterosuperior rotator cuff tears, but when it is present it is associated with a better clinical result. Preoperative shoulder function and general strength influence the clinical result. Female patients with poor shoulder function and generalized muscle weakness prior to surgery have a greater likelihood of having a poor clinical result.

The painful shoulder: when to inject and when to refer.

Physicians can usually diagnose the cause of shoulder pain by performing a focused history and physical examination and ordering anteroposterior and lateral radiographs. Treatment depends on the cause and can include physical therapy, injections of corticosteroids into the joint space or bursa, and surgery. This paper reviews the diagnosis and treatment of impingement syndrome, adhesive capsulitis, rotator cuff tears, and arthritis of the glenohumeral joint and acromioclavicular (AC) joint.

Assessment of the canine model of rotator cuff injury and repair.

Animal shoulder models are used to systematically investigate the factors influencing rotator cuff injury and repair. Each model has advantages and disadvantages that must be considered in the context of the specific research questions being asked. This study evaluated the utility of the canine model for studies of acute, full-thickness rotator cuff tendon injury and repair. We found that time-zero failure load is dependent on the suture type and configuration used for repair. Acute, full-width tendon repairs fail anatomically within the first days after surgery in the canine model, regardless of suture type, suture configuration, or postoperative protocol. Robust scar tissue forms in the gap between the failed tendon end and the humerus, which can be visually, mechanically, and histologically misconstrued as tendon if an objective test of repair connectivity is not performed. We conclude that a full-width injury and repair model in the canine will provide a rigorous test of whether a new repair strategy or postoperative protocol, such as casting or temporary muscle paralysis, can maintain repair integrity in a high-load environment. Alternatively, a partial-width tendon injury model allows loads to be shared between the tendon repair and the remaining intact portion of the infraspinatus tendon and prohibits complete tendon retraction. Thus a partial-width injury in the canine may model the mechanical environment of many single tendon tears in the human injury condition and warrants further investigation.

Locations for screw fixation beyond the glenoid vault for fixation of glenoid implants into the scapula: an anatomic study.

Screw fixation is often required for glenoid implants and glenoid bone grafting, yet no study has evaluated the complex and irregular anatomy of the scapula to determine the best positions for the screws. Current implants rely solely on the bone in the glenoid vault for screw fixation, but in cases with glenoid bone loss, screw fixation may not confer adequate stability. The purpose of this study was to find the best positions for screws that are secured in bone beyond the glenoid vault. Twenty-seven scapulae from the Hamann-Todd osteologic collection underwent a computed tomography scan, and the images were transferred to a custom computer program that allowed 3-dimensional manipulation of the scapular images. Virtual screws were inserted into the scapula through the glenoid fossa, and the starting points and screw lengths were recorded. The coordinates of the starting points were scaled to allow comparisons among the different sizes of scapula. Once the ideal screw position was found, the angle of insertion was altered by 15 degrees in 4 directions, and the resulting screw length was recorded to show the effects of screw insertion error. Three screws could be inserted through the glenoid fossa into bone beyond the glenoid vault. The superior screw had a median length of 29 mm and exited at the junction of the coracoid and the suprascapular notch. The middle screw had a median length of 60 mm and exited at the junction of the spine and the scapular body. The inferior screw had a median length of 75 mm and exited posterior to the tip of the scapula. When the starting positions were constrained by a symmetric implant, the median superior screw length was 19 mm, the median inferior screw length was 61 mm, and the median middle screw length was 55 mm. Screw fixation in bone beyond the glenoid vault can be used for fixation of glenoid implants or glenoid bone grafting. Future studies are required to test the biomechanical stability of this new screw configuration, as well as methods and tools for precise implantation of the screws into the described locations. Once these studies are completed revision total shoulder arthroplasty with severe glenoid bone loss may be treated in 1 stage with screw fixation of a glenoid implant over bulk allograft.

Porcine small intestine submucosa augmentation of surgical repair of chronic two-tendon rotator cuff tears. A randomized, controlled trial.

BACKGROUND: Evidence to justify the use of porcine small intestine submucosa to augment repairs of large and massive rotator cuff tears is based on favorable results found in studies of Achilles tendon and infraspinatus tendon repairs in canines. The purpose of this study was to determine the effectiveness of a small intestine submucosal patch to augment the repair of chronic two-tendon rotator cuff tears in humans. METHODS: Thirty shoulders with a chronic two-tendon rotator cuff tear that was completely repairable with open surgery were randomized to be treated with either augmentation with porcine small intestine mucosa or no augmentation. All patients completed a PENN shoulder-score questionnaire preoperatively and at the time of the latest follow-up (at an average of fourteen months). Magnetic resonance imaging showed that nine shoulders had a large tear and twenty-one had a massive tear. All patients underwent a magnetic resonance imaging scan with intra-articular gadolinium one year after the repair to assess the status of the rotator cuff. RESULTS: The rotator cuff healed in four of the fifteen shoulders in the augmentation group compared with nine of the fifteen in the control group (p = 0.11). The median postoperative PENN total score was 83 points in the augmentation group compared with 91 points in the control group (p = 0.07). Healing of the defects in both groups demonstrated a strong correlation with the patients' clinical scores. The median postoperative PENN total score was 96 points in the group with a healed repair and 81 points in the group with a failed repair (p = 0.007). The percentage change between the preoperative and postoperative patient satisfaction scores was 400% in the group with a healed repair, and 50% in the group with a failed repair (p = 0.04). CONCLUSIONS: Augmentation of the surgical repair of large and massive chronic rotator cuff tears with porcine small intestine submucosa did not improve the rate of tendon-healing or the clinical outcome scores. On the basis of these data, we do not recommend using porcine small intestine submucosa to augment repairs of massive chronic rotator cuff tears done with the surgical and postoperative procedures described in this study.

Thermal capsulorrhaphy for the treatment of shoulder instability.

Thermal capsulorrhaphy has been used to treat many different types of shoulder instability, including multidirectional instability, unidirectional instability, and microinstability in overhead-throwing athletes. A device that delivers laser energy or radiofrequency energy to the capsule tissue causes the collagen to denature and the capsule to shrink. The optimal temperature to achieve the most shrinkage without causing necrosis of the tissue is between 65 degrees and 75 degrees centigrade. This treatment causes a significant decrease in mechanical stiffness for the first 2 weeks, and then, after the tissue undergoes active cellular repair from the surrounding uninjured tissue, the mechanical properties return to near normal by 12 weeks. If the thermal energy is applied in a grid pattern, then the tissue heals with more stiffness by 6 weeks. Clinical studies on thermal capsulorrhaphy for the treatment of multidirectional instability have shown a high rate of recurrent instability (12%-64%). The clinical studies on unidirectional instability showed much better recurrence rates (4%-25%), but because most of the patients also underwent concomitant Bankart repairs and superior labral anterior posterior lesion repairs, the efficacy of the thermal treatment cannot be ascertained. A randomized controlled trial would be needed to assess whether instability with Bankart lesions requires augmentation with thermal capsulorrhaphy. For the patients with microinstability who are overhead-throwing athletes, thermal capsulorrhaphy has shown varying results from a 97% rate of return to sports to a 62% rate of return to sports. Complications of this technique include temporary nerve injuries that usually involve the sensory branch of the axillary nerve and thermal necrosis of the capsule, which is rare.

Rotator cuff repair augmentation in a canine model with use of a woven poly-L-lactide device.

BACKGROUND: Despite advances in surgical treatment options, failure rates of rotator cuff repair have continued to range from 20% to 90%. Hence, there is a need for new repair strategies that provide effective mechanical reinforcement of rotator cuff repair as well as stimulate and enhance the intrinsic healing potential of the patient. The purpose of this study was to evaluate the extent to which augmentation of acute repair of rotator cuff tendons with a newly designed poly-L-lactide repair device would improve functional and biomechanical outcomes in a canine model. METHODS: Eight adult, male mongrel dogs (25 to 30 kg) underwent bilateral shoulder surgery. One shoulder underwent tendon release and repair only, and the other was subjected to release and repair followed by augmentation with the repair device. At twelve weeks, tendon retraction, cross-sectional area, stiffness, and ultimate load of the repair site were measured. Augmented repairs underwent histologic assessment of biocompatibility. In addition, eight pairs of canine cadaver shoulders underwent infraspinatus injury and repair with and without device augmentation with use of identical surgical procedures and served as time-zero biomechanical controls. Eight unpaired, canine cadaver shoulders were included as normal biomechanical controls. RESULTS: At time zero, repair augmentation significantly increased the ultimate load (23%) (p = 0.034) but not the stiffness of the canine infraspinatus tendon repair. At twelve weeks, the poly-L-lactide scaffold was observed to be histologically biocompatible, and augmented repairs demonstrated significantly less tendon retraction (p = 0.008) and significantly greater cross-sectional area (137%), stiffness (26%), and ultimate load (35%) than did repairs that had not been augmented (p < 0.001, p = 0.002, and p = 0.009, respectively). CONCLUSIONS: While limiting but not eliminating tendon repair retraction, the augmentation device provided a tendon-bone bridge and scaffold for host tissue deposition and ingrowth, resulting in improved biomechanical function of the repair at twelve weeks.

The influence of three-dimensional computed tomography images of the shoulder in preoperative planning for total shoulder arthroplasty.

BACKGROUND: Arthritic changes to glenoid morphology can be difficult to fully characterize on both plain radiographs and conventional two-dimensional computer tomography images. We tested the hypothesis that three-dimensional imaging of the shoulder would increase inter-rater agreement for assessing the extent and location of glenoid bone loss and also would improve surgical planning for total shoulder arthroplasty. METHODS: Four shoulder surgeons independently and retrospectively reviewed the preoperative computed tomography scans of twenty-four arthritic shoulders. The blinded images were evaluated with conventional two-dimensional imaging software and then later with novel three-dimensional imaging software. Measurements and preoperative judgments were made for each shoulder with use of each imaging modality and then were compared. The glenoid measurements were glenoid version and bone loss. The judgments were the zone of maximum glenoid bone loss, glenoid implant fit within the glenoid vault, and how to surgically address abnormal glenoid version and bone loss. Agreement between observers was evaluated with use of intraclass correlation coefficients and the weighted kappa coefficient (kappa), and we determined if surgical decisions changed with use of the three-dimensional data. RESULTS: The average glenoid version (and standard deviation) measured -17 degrees +/- 2.2 degrees on the two-dimensional images and -19 degrees +/- 2.4 degrees on the three-dimensional images (p < 0.05). The average posterior glenoid bone loss measured 9 +/- 2.3 mm on the two-dimensional images and 7 +/- 2 mm on the three-dimensional images (p < 0.05). The average anterior bone loss measured 1 mm on both the two-dimensional and the three-dimensional images. However, the intraclass correlation coefficients for anterior bone loss increased significantly with use of the three-dimensional data (from 0.36 to 0.70; p < 0.05). Observers were more likely to locate mid-anterior glenoid bone loss on the basis of the three-dimensional data (p < 0.05). The use of three-dimensional data provided greater agreement among observers with regard to the zone of glenoid bone loss, glenoid prosthetic fit, and surgical decision-making. Also, when the judgment of implant fit changed, observers more often determined that it would violate the vault walls on the basis of the three-dimensional data (p < 0.05). CONCLUSIONS: The use of three-dimensional imaging can increase inter-rater agreement for the analysis of glenoid morphology and preoperative planning. Important considerations such as the extent and location of glenoid bone loss and the likelihood of implant fit were influenced by the three-dimensional data.