Eclipse stemless shoulder prosthesis vs. Univers II shoulder prosthesis: a multicenter, prospective randomized controlled trial.

BACKGROUND: Total shoulder arthroplasty is an accepted treatment for glenohumeral osteoarthritis. The Arthrex Eclipse shoulder prosthesis is a stemless, canal-sparing humeral prosthesis with bone ingrowth capacity on the trunnion, as well as through the fenestrated hollow screw, that provides both diaphyseal and metaphyseal load sharing and fixation. METHODS: Between 2013 and 2018, 16 sites in the United States enrolled 327 patients (Eclipse in 237 and Arthrex Univers II in 90). All patients had glenohumeral arthritis refractory to nonsurgical care. Strict exclusion criteria were applied to avoid confounding factors such as severe patient comorbidities, arthritis not consistent with osteoarthritis, and medical or prior surgical treatments that may have affected outcomes. Patients were randomized to the Eclipse or Univers II group via block randomization. RESULTS: In total, 149 Eclipse and 76 Univers II patients reached 2-year follow-up (139 Eclipse patients [93.3%] and 68 Univers II patients [89.5%] had complete data). The success rate using the Composite Clinical Success score was 95% in the Eclipse group vs. 89.7% in the Univers II group. No patient exhibited radiographic evidence of substantial humeral radiolucency, humeral migration, or subsidence at any point. Reoperations were performed in 7 patients (3.2%) in the Eclipse group and 3 (3.8%) in the Univers II group. CONCLUSION: The Arthrex Eclipse shoulder prosthesis is a safe and effective humeral implant for patients with glenohumeral arthritis at 2-year follow-up, with no differences in outcomes compared with the Univers II shoulder prosthesis.

Biomechanical Analysis of Superior and Anterior Precontoured Plate Fixation Techniques for Neer Type II-A Clavicle Fractures.

OBJECTIVE: There are limited biomechanical data supporting the use of anterior or superior-lateral precontoured clavicle plates for the treatment of displaced Neer type II-A clavicle fractures. The objectives of this study were as follows: (a) compare noncontoured versus precontoured superior plating; (b) compare use of locking versus nonlocking screws in the lateral fragment for superior precontoured plates; and (c) compare superior versus anterior precontoured plates with locking lateral fragment screws. METHODS: The following constructs were tested on a synthetic clavicle model simulating a Neer type II-A fracture: (a) superior precontoured plate with locking (SUP-L, n = 6); (b) superior precontoured plate with nonlocking (SUP-NL, n = 8); (c) anterior precontoured plate with locking (ANT-L, n = 7); and (d) superior noncontoured locking compression plate (SUP-LCP, n = 6). Constructs were subjected to cyclical cantilever loads. Construct stiffness and survival (cycles to failure) were documented. Mann-Whitney U tests were performed for group-wise statistical comparison (α = 0.05) of data. RESULTS: The SUP-L construct was significantly stiffer than both SUP-LCP and ANT-L constructs (P < 0.02). The SUP-NL construct was stiffer than the SUP-L (P = 0.03) construct. Both SUP-L and ANT-L precontoured constructs survived longer than the noncontoured SUP-LCP construct (P < 0.022). The SUP-L construct survived longer than the SUP-NL (P = 0.013) and the ANT-L (P = 0.008) constructs. CONCLUSIONS: Superior precontoured plates yielded biomechanically superior constructs compared with anterior precontoured and superior noncontoured plates. Using locking screws in the lateral fragment over nonlocking screws may improve overall superior precontoured plate construct survivability. However, our results were limited to a synthetic biomechanical model and require further investigation to establish a clinical correlation.

In vitro assessment of phthalate acid esters-trypsin complex formation.

In this work, interactions of three phthalate acid esters (PAEs), including dimethyl phthalate (DMP), diethyl phthalate (DEP) and dibutyl phthalate (DBP), with trypsin have been studied in vitro, under simulated physiological conditions using multi-spectroscopic techniques and molecular modeling. The results show that these PAEs can bind to the trypsin, forming trypsin-PAEs complexes, mainly via hydrophobic interactions, with the affinity order of DMP > DEP > DBP. Binding to the PAEs is found to result in molecular deformation of trypsin. The modeling results suggest that only DBP can bind with the amino acid residues of the catalytic triad and S1 binding pocket of trypsin, leading to potential competitive enzyme inhibition.

The outcome of examination (manipulation) under anesthesia on the stiff elbow after surgical contracture release.

HYPOTHESIS: We have used a technique of elbow examination under anesthesia in select patients after surgical release to assess the smoothness of the articulation, evaluate stability, and to stretch the flexion and rotation arcs. MATERIALS AND METHODS: The study comprised 51 consecutive patients who underwent an examination under anesthesia between January of 1996 and December of 2001. RESULTS: The examination occurred a mean of 40 days after surgery. Forty-four patients with a minimum of 12 months follow-up revealed a mean pre-examination arc of 33 degrees , which improved to 73 degrees at the final assessment. Three patients had no appreciable change (<10 degrees ) in the total arc, and 1 patient lost motion. Four patients underwent a second examination under anesthesia at a mean of 119 days after the first examination. The average pre-examination arc of 40 degrees increased to 78 degrees at the final assessment (mean improvement, 38 degrees ). The only complication was worsening of ulnar paresthesias in 3; with 2 resolving spontaneously, and 1 patient requiring anterior ulnar nerve transposition. CONCLUSIONS: Examination (manipulation) under anesthesia can be a valuable adjunctive procedure to help regain the motion obtained at the time of surgical release. Because this was not a controlled series, additional studies might be conducted to refine those not benefiting from this procedure. In our series no permanent complications were noted.

The effect of cartilage-derived morphogenetic protein 2 on initial healing of a rotator cuff defect in a rat model.

This animal study evaluated the healing of supraspinatus tendon tears by use of a cartilage-derived morphogenetic protein 2 growth factor (CDMP-2) delivered to the repair. Forty-eight rats had bilateral, surgically created complete tears repaired by sutures with the growth factor introduced on one side. They were killed at 2, 3, 4, and 6 weeks, and the strength of the repairs was determined and histologic analysis performed. At 4 and 6 weeks, the CDMP-2-treated repairs were significantly stronger than the untreated repairs and histologic analysis showed more organized healing. The use of growth factors introduced at the time of rotator cuff repair might promote more rapid healing and subsequent, rapid patient rehabilitation.

Recurrent anterior glenohumeral instability with onset after forty years of age: the role of the anterior mechanism.

Recurrent instability in patients over forty years of age is felt to occur primarily as a result of an associated rotator cuff tear. This is often referred to as the "posterior mechanism." We reviewed our patients over the age of forty who underwent an anterior shoulder repair to identify the incidence of capsulolabral detachments and the role of an "anterior mechanism" in this patient population. A retrospective review of all patients from 1985 to 2000 was performed to identify patients who had surgery for recurrent instability that began after forty years of age. Of the 265 patients records reviewed, 11 patients were identified who fulfilled the inclusion criteria. Of the 11 patients identified, 9 patients underwent anterior capsulolabral reconstruction for recurrent instability; the remaining two patients underwent repair of large rotator cuff tears. All 9 patients had a capsulolabral detachment, 4 had a rotator interval defect, 2 had anterior and inferior capsular redundancy, 1 had a small rotator cuff tear and 1 had an anterior capsular avulsion from the humeral head. At minimum follow-up of 32 months none of the patients reported episodes of instability. The reported incidence of rotator cuff tears in patients over the age of forty following an initial traumatic anterior glenohumeral dislocation ranges from 35% to 100%. When recurrent instability occurs, it is postulated to occur via a "posterior mechanism" (i.e., secondary to a significant full-thickness rotator cuff tear). However, all of our patients had an anterior capsulolabral detachment as the "common lesion" associated with recurrent instability. Although small, this series emphasizes the role of the "anterior mechanism" in patients who develop recurrent instability after the age of forty. A high rate of success was achieved by addressing the pathoanatomic changes identified.

Revision anterior shoulder repair for recurrent anterior glenohumeral instability.

Although the operative management of recurrent anterior glenohumeral instability has received significant attention in literature, the outcome of revision anterior shoulder repair is much less frequently reported. We report the results of our experience with this challenging problem. Retrospective chart review identified 29 patients who underwent revision anterior shoulder repair. Prior procedures included eight Bankart repairs, seven capsular shifts, 10 combined Bankart and capsular shift procedures, three Putti-Platt procedures, two staple capsulorrhaphies, two Bristow procedures, seven arthroscopie procedures, and one Magnuson-Stack. The average age of the patients was 31.6 years (range: 18 to 52 years) and the dominant extremity was involved in 69%. Findings at the time of revision anterior shoulder repair included 22 patients with capsulolabral detachment, 24 with capsular redundancy, and 14 with rotator interval defects. Twenty-three of the 29 patients were available for at least a two-year follow-up. Twenty-one (91%) remain stable. One patient was non-compliant with the postoperative immobilization and re-dislocated within the first month. The second patient, who had a prior Bankart procedure followed by a capsular shift two years later, underwent a capsular shift for significant capsular laxity. He re-dislocated approximately 15 months postoperatively. Our success rate of 91% in this small series approaches the results of primary open repair for recurrent glenohumeral instability. To achieve a successful outcome, it is essential to address all pathology at the time of revision repair.