Robert U. Hartzler

Tendon Transfer Options About the Shoulder in Patients with Brachial Plexus Injury

BACKGROUND The purpose of this study was to evaluate the early outcome of shoulder tendon transfer in patients with brachial plexus injury and to determine the factors associated with favorable outcomes. METHODS Fifty-two patients with traumatic brachial plexus injury and a paralytic shoulder were included in the study. All patients were evaluated at a mean of nineteen months (range, twelve to twenty-eight months) postoperatively. Twelve patients had a C5-6 injury, twenty-two had a C5-7 injury, five had a C5-8 injury, and thirteen had a C5-T1 injury. Transfer of the lower portion of the trapezius muscle was performed either in isolation or as part of multiple tendon transfers to improve shoulder function. Additional muscles transferred included the middle and upper portions of the trapezius, levator scapulae, upper portion of the serratus anterior, teres major, latissimus dorsi, and pectoralis major. RESULTS All patients had a stable shoulder postoperatively. Shoulder external rotation improved substantially in all patients from no external rotation (hand-on-belly position) to a mean of 20° (p = 0.001). Patients who underwent additional transfers had marginal improvement of shoulder flexion, from a mean of 10° preoperatively to 60° postoperatively, and of shoulder abduction, from a mean of 10° to 50° (p = 0.01 for each). Mean pain on a visual analog scale improved from 6 points preoperatively to 2 points postoperatively. The mean Disabilities of the Arm, Shoulder and Hand (DASH) score improved from 59 to 47 points (p = 0.001). The mean Subjective Shoulder Value improved from 5% to 40% (p = 0.001). Greater age, higher body mass index, and more extensive nerve injury were associated with a poorer DASH score in a multivariate analysis (p = 0.003). CONCLUSIONS Tendon transfers about the shoulder can improve shoulder function in patients with brachial plexus injury resulting in a paralytic shoulder. Significant improvement of shoulder external rotation but only marginal improvements of shoulder abduction and flexion can be achieved. The outcome can be expected to be better in patients with less severe nerve injury.

Reverse shoulder arthroplasty for massive rotator cuff tear: risk factors for poor functional improvement

BACKGROUND Some patients unexpectedly have poor functional improvement after reverse shoulder arthroplasty (RSA) for massive rotator cuff tear without glenohumeral arthritis. Our aim was to identify risk factors for this outcome. We also assessed the value of RSA for cases with poor functional improvement vs. METHODS The study was a retrospective case-control analysis for primary RSA performed for massive rotator cuff tear without glenohumeral arthritis with minimum 2-year follow-up. Cases were defined as Simple Shoulder Test (SST) score improvement of ≤1, whereas controls improved SST score ≥2. Risk factors were chosen on the basis of previous association with poor outcomes after shoulder arthroplasty. Latissimus dorsi tendon transfer results were analyzed as a subgroup. Value was defined as improvement in American Shoulder and Elbow Surgeons (ASES) score per

Surgical capsular release reduces flexion contracture in a rabbit model of arthrofibrosis

10,000 hospital cost. RESULTS In a multivariate binomial logistic regression analysis, neurologic dysfunction (P = .006), age <60 years (P = .02), and high preoperative SST score (P = .03) were independently associated with poor functional improvement. Latissimus dorsi tendon transfer patients significantly improved in active external rotation (-0.3° to 38.7°; P < .01). The value of RSA (ΔASES/

Glenosphere dissociation after reverse shoulder arthroplasty

10,000 cost) for cases was 0.8 compared with 17.5 for controls (P < .0001). CONCLUSIONS Young age, high preoperative function, and neurologic dysfunction were associated with poor functional improvement. Surgeons should consider these associations in counseling and selection of patients. Concurrent latissimus dorsi transfer was successful in restoring active external rotation in a subgroup of patients. The critical economic importance of improved patient selection is emphasized by the very low value of the procedure in the case group.

Clinical and radiographic factors influencing the results of revision rotator cuff repair.

Animal models of joint contracture may be used to elucidate the mechanisms of arthrofibrosis. Patients with joint contracture commonly undergo surgical capsular release. Previous animal models of joint contracture do not simulate this aspect of arthrofibrosis. We hypothesize that a surgical capsular release will decrease the severity of arthrofibrosis in this rabbit model. A capsular contracture was surgically created in 20 skeletally mature rabbits. Eight weeks later, ten rabbits underwent capsular release, which consisted of elevation of the posterior capsule through a lateral incision and manipulation under anesthesia. Ten rabbits had a sham incision, without release (control group). Immediately after release or sham surgery, extension loss (calculated by subtracting the knee extension angle (degrees) of the operative limb from the nonoperative, contralateral limb) was measured using fluoroscopy. All animals were sacrificed following 16 weeks of postoperative free cage activity. At sacrifice, joint contracture was measured using a custom, calibrated device. The histology of the posterior joint capsule was assessed at sacrifice. All animals survived both operations without complications. Immediately after surgical release or sham surgery, the average extension loss was 129.2 ± 10.7° in the control group versus 29.6 ± 8.2° in the capsular release group (p = 0.0002). Following 16 weeks of remobilization, the average extension loss of the control and capsular release animals were 49.0 ± 12.7° and 36.5 ± 14.2°, respectively (p = 0.035). There were no histological differences between the two groups. In this animal model, a surgical capsular release decreased the extension loss (flexion contracture) immediately after surgery, as well as following sixteen weeks of remobilization. There were no histological changes detected in the posterior joint capsule.

Medial Biceps Sling Takedown May Be Necessary to Expose an Occult Subscapularis Tendon Tear

BACKGROUND Reverse shoulder arthroplasty (RSA) is gaining popularity for the treatment of debilitating shoulder disorders. Despite marked improvements in patient satisfaction and function, the RSA complication rate is high. Glenosphere dissociation has been reported and may result from multiple mechanisms. However, few RSA retrieval studies exist. METHODS We reviewed our RSA database and identified patients with glenosphere dissociation between 1999 and 2013. Prosthesis type, glenosphere size, and contributing factors to dissociation were noted. Five retrieved implants were available for analysis, and evidence of wear or corrosion on the Morse taper was documented. Further, we biomechanically investigated improper Morse taper engagement that may occur intraoperatively as a potential cause of acute dissociation. RESULTS Thirteen patients with glenosphere dissociation were identified (0.5 months to 7 years postoperatively). Glenosphere size distribution was as follows: 32 mm (n = 1), 36 mm (n = 4), 40 mm (n = 6), and 44 mm (n = 2). Incidence of dissociation was correlated to glenosphere size (P < .001). Taper damage was limited to fretting wear, and there was minimal evidence of taper corrosion. Biomechanically, improper taper engagement reduced the torsional capacity of the glenosphere-baseplate interface by 60% from 19.2 ± 1.0 N-m to 7.5 ± 1.5 N-m. CONCLUSION We identified several mechanisms contributing to glenosphere dissociation after RSA, including trauma and improper taper engagement. Limited evidence of corrosive wear on the taper interface was identified. Although it is rare, the incidence of glenosphere dissociation was higher when 40- and 44-mm glenospheres were implanted compared with smaller glenospheres (32 and 36 mm), probably because of the larger exposed surface area for potential impingement.

Superior Capsular Reconstruction

Purpose: Historically, results of open revision of rotator cuff repair have been mixed and often poor. We reviewed the outcomes of revision rotator cuff repair with a detailed analysis of clinical and radiographic risk factors in order to improve patient selection for this type of surgery. Materials and Methods: Thirty-six patients (37 shoulders) underwent first-time, open revision rotator cuff repair between 1995 and 2005. Average follow-up was 7.0 years (range 1-14.9 years). The tear size was small in 1 shoulder, medium in 8, large in 22 and massive in 6. Associations of 29 clinical and radiographic factors with the outcomes of pain, motion, and function were assessed. Results: Satisfactory outcome occurred in 22 shoulders (59%): An excellent result in 2, a good result in 7, and a fair result in 13. Unsatisfactory, poor results occurred in 15. Pain was substantially reduced in 25 (68%). Median pain scores decreased to five from a pre-operative eight (P = 0.002). Median motion did not change from pre-operative to post-operative. The chance of a satisfactory outcome and improved post-operative motion were associated with males, greater pre-operative motion, increased acromial humeral distance, the absence of glenohumeral arthritis, or a degenerative re-tear. Conclusions: Revision rotator cuff repair, although a safe operation, with a low re-operative rate, has very mixed overall results. By knowing the factors associated with success, surgeons can better counsel patients and with this increased knowledge, consider alternative treatment choices.

Kinematic impact of size on the existing glenohumeral joint in patients undergoing reverse shoulder arthroplasty

With a systematic approach to diagnosis, including a thorough history, physical examination, advanced imaging, and arthroscopic evaluation, most subscapularis tendon tears may be readily discovered. Occult tears, on the other hand, may escape arthroscopic detection if a high index of suspicion and certain intraoperative examination steps are lacking. We describe an occult tear pattern in which a subscapularis tendon tear was completely hidden by an intact medial biceps tendon sling. Takedown of the sling, which was expendable because a tenodesis was planned, was required to expose this occult tear. Awareness of occult subscapularis tear patterns makes diagnosis and repair possible.

Pathoanatomy of Rotator Cuff Tears

Superior capsular reconstruction (SCR) of the shoulder has recently gained popularity as an option for joint-preserving shoulder surgery for patients with an irreparable rotator cuff tear. In the absence of glenohumeral arthritis, rotator cuff tear irreparability should only be diagnosed for most patients after a careful diagnostic arthroscopy. Superior capsular reconstruction adds biological, passive, superior constraint to the glenohumeral joint, thereby optimizing the rotator cuff force couples and improving joint kinematics. At short-term follow-up, SCR has been shown to be effective for pain relief and restoration of active shoulder motion, even in the worst cases of shoulder dysfunction (true shoulder pseudoparalysis). The rapid early adoption and expansion of SCR is justified by its excellent anatomical, biomechanical, and short-term clinical results. The techniques for arthroscopic SCR using dermal allograft continue to improve; however, the operation remains technically demanding. Patients with risk factors for irreparability and who might benefit from reconstruction of the superior capsule should be counseled about the operation as an additional, joint-preserving procedure that can be done in conjunction with arthroscopic, partial rotator cuff repair. [Orthopedics. 2017; 40(5):271-280.].

Massive Rotator Cuff Lesion: Arthroscopic Repair

BACKGROUND Glenohumeral relationships in reverse shoulder arthroplasty patients have not been previously reported. The purpose of this study was to quantify and compare the shoulder spatial relationships and moment arms. Measurements were used to define general size categories and determine if sizes scale linearly for all metrics. METHODS Ninety-two shoulders of patients undergoing primary reverse shoulder arthroplasty for functionally-deficient massive rotator cuff tear without bony deformity or deficiency were evaluated using three-dimensional CT reconstructions and computer-aided design software. Multiple glenohumeral relationships (including moment arm) were measured and evaluated for size stratification and linearity. Generalized linear modeling was used to investigate how predictive glenoid height, coronal humeral head diameter, and gender were of greater tuberosity positions. FINDINGS The 92 shoulders were grouped based on glenoid height: small (<33.4mm), medium (33.4-38.0mm), and large (>38.0mm). All relationships varied between groups. The humeral head size, glenoid width, lateral offset, and moment arm all independently increased linearly (r(2)≥0.92) but the rate of increase varied (slope range: 0.59-1.92). Glenoid height, coronal humeral head diameter and gender predicted the greater tuberosity position within mean 1.09mm (standard deviation (SD) 0.84mm) of actual position in 90% of the population. INTERPRETATION Distinct groups exist based on the size of the glenoid in shoulder arthroplasty patients. Shoulder modeling should account for size groups, sex, and non-uniform linear scaling of morphometric parameters. Prediction of the greater tuberosity offset can be made using sex and size parameters. Clinical implications include appropriate prosthetic size selection and avoiding large deviations in non-anatomic reconstructions.