Donald P. Endrizzi

Shift of the posteroinferior aspect of the capsule for recurrent posterior glenohumeral instability.

Thirty-five shoulders in thirty-four patients were treated with a superior shift of the posteroinferior aspect of the capsule because of recurrent posterior glenohumeral subluxation and dislocation. The physical examination revealed three types of posterior instability in these patients preoperatively: unidirectional (six shoulders), bidirectional (posterior and inferior) (seven shoulders), and multidirectional (posterior and inferior dislocation with anterior subluxation) (twenty-two shoulders). Eleven shoulders had had previous operative procedures. At the time of the index operation, the most common abnormal findings in these shoulders were capsular redundancy and excessive volume of the glenohumeral joint. Complete detachment of the posterior aspect of the labrum was found in only four shoulders. There was no excessive glenoid retroversion in these patients. All thirty-four patients were available for follow-up at an average of five years (range, two to twelve and a half years) postoperatively. Over-all, the result for seventeen of the thirty-five shoulders was rated as excellent; eleven, as good; one, as fair; and six, as poor. Four shoulders became unstable again. Six of the seven unsatisfactory results were in shoulders that had had previous attempts at stabilization. A successful result was achieved in twenty-three of the twenty-four shoulders in which the superior shift of the posteroinferior aspect of the capsule was the initial repair.

Treatment of Tibial Defects and Nonunions Using Ipsilateral Vascularized Fibular Transposition

Eight patients had nine ipsilateral vascularized fibular transpositions (IVFTs) in the period 1978-1987. The procedure, which involves no microvascular anastomosis, was done for difficult problems of the tibia including two long-standing posttraumatic nonunions, three allograft nonunions after tumor surgery, and four segmental tibial defects also after tumor surgery. The average duration of problems before surgery was 3.5 years, and the patients averaged 3.1 procedures before IVFT. The patients were followed for an average of 52.4 months. The average time to union was 4.2 months, and in all patients the grafts healed within six months. Late fracture of the graft developed in two patients after fixation removal; one required an additional procedure, and both eventually healed. Ipsilateral vascularized fibular grafting is a useful alternative to conventional, nonvascularized grafts for difficult tibial nonunions and segmental defects. It offers the advantages of a vascularized graft (early healing and hypertrophy), yet avoids the time-consuming microvascular anastomosis and distant donor site morbidity of free fibular grafts.

Nonunion of the clavicle treated with plate fixation: A review of forty-seven consecutive cases

Forty-seven consecutive patients underwent superior plating for clavicular nonunion between 1995 and 2005. This retrospective analysis was performed to assess the efficacy of plate fixation and the need for iliac crest bone grafting. Forty-three patients were treated with pelvic reconstruction plates and four with straight dynamic compression plates. Of the patients, 30 were treated with local bone graft only, 14 with demineralized bone matrix, and 3 with distant autogenous bone graft. Of the fractures, 93% united after a single operation. Of the patients, 69% returned the Disabilities of the Arm, Shoulder and Hand questionnaire. The mean Disabilities of the Arm, Shoulder and Hand score was 14.6 (range, 0-53). Plate prominence or sensitivity resulted in removal in 20% of cases. We believe that superiorly applied plate fixation is effective for the treatment of clavicular nonunion. Distant autogenous bone graft is not necessary in most cases to obtain union.

Experimental Demonstration of the Collisionless Plasmoid Instability below the Ion Kinetic Scale during Magnetic Reconnection.

The spontaneous formation of magnetic islands is observed in driven, antiparallel magnetic reconnection on the Terrestrial Reconnection Experiment. We here provide direct experimental evidence that the plasmoid instability is active at the electron scale inside the ion diffusion region in a low collisional regime. The experiments show the island formation occurs at a smaller system size than predicted by extended magnetohydrodynamics or fully collisionless simulations. This more effective seeding of magnetic islands emphasizes their importance to reconnection in naturally occurring 3D plasmas.

Early Debris Formation with a Porous Tantalum Glenoid Component: Radiographic Analysis with 2-Year Minimum Follow-up.

BACKGROUND Porous tantalum has been used effectively in hip, knee, and reverse shoulder arthroplasty implants. However, a first-generation porous tantalum glenoid component for use in anatomic shoulder arthroplasty previously demonstrated failure, with failure usually preceded by the appearance of intra-articular metallic debris. After redesign, the component was reintroduced in 2009. The purpose of the current study was to evaluate the radiographic and clinical outcomes of the redesigned glenoid component. METHODS Sixty-eight patients undergoing total shoulder arthroplasty received a Trabecular Metal porous tantalum glenoid component (73 components; 5 patients underwent staged bilateral procedures). No polymethylmethacrylate cement was used (off-label usage in the U.S.). A grading system to assess metallic debris formation was developed using radiographs of the previous generation of porous tantalum glenoid components that failed. Radiographs from the current series were independently reviewed by 2 shoulder arthroplasty specialists, and their results were compared. Glenoid components were evaluated for signs of bone ingrowth and metallic debris formation. RESULTS Sixty-six (90%) of the 73 components were evaluated at a minimum of 2 years of follow-up (mean radiographic follow-up of 50.8 months; range, 24 to 68 months). Of these, 92.4% demonstrated minimal or no glenoid radiolucency. Overall, the prevalence of metallic tantalum debris formation was 44% (29 of 66). Sequential radiograph review demonstrated that the incidence of metallic debris formation increased for each year of follow-up, with radiographs from 2, 3, 4, and ≥5 years of follow-up demonstrating a metallic debris incidence of 23%, 36%, 49%, and 52%, respectively. Additionally, the severity of metallic debris formation increased with follow-up duration. There was no component dissociation or revision due to implant breakage in this series. CONCLUSIONS The porous tantalum glenoid component studied had excellent short-term component fixation. However, the development of metallic debris, increasing in both overall incidence and degree of severity over time, raises concern for potential failure of this glenoid component. Longer follow-up is required. LEVEL OF EVIDENCE Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Critical shoulder angle is associated with full-thickness rotator cuff tears in patients with glenohumeral osteoarthritis.

BACKGROUND Higher critical shoulder angle (CSA) is correlated with rotator cuff tears (RCTs), whereas lower CSA is associated with glenohumeral osteoarthritis (OA). Our goal was to investigate whether patients with concurrent glenohumeral OA and full-thickness RCTs demonstrate a higher CSA than patients with OA alone. METHODS Using a 2-surgeon shoulder arthroplasty registry, we identified 31 patients with glenohumeral OA and full-thickness RCTs confirmed by plain radiography and magnetic resonance imaging, respectively. Sixty-two age- and gender-matched controls (1:2 ratio) with glenohumeral OA and an intact rotator cuff were identified from the same registry. Two independent observers evaluated the radiographs for CSA and acromiohumeral index. RESULTS The average CSA was 30° in the OA control group and 35° in the concurrent RCT and OA group (P < .0001). Acromiohumeral index was comparable between the groups (P = .13). Interobserver reliability of the independent reviewers was excellent (κ = 0.89; Ρ = 0.95). The receiver operating characteristic curve for CSA demonstrated that a value >35° was 90% specific and 52% sensitive for a full-thickness RCT in the setting of OA (area under curve = 0.84). CONCLUSION Concurrent glenohumeral OA and full-thickness RCT are associated with greater CSA values compared with patients with glenohumeral OA alone. The CSA measurement may be useful in determining the need for magnetic resonance imaging to assess rotator cuff integrity in the arthritic population.

Ultrasound gel minimizes third body debris with partial hardware removal in joint arthroplasty

Hundreds of thousands of revision surgeries for hip, knee, and shoulder joint arthroplasties are now performed worldwide annually. Partial removal of hardware during some types of revision surgeries may create significant amounts of third body metal, polymer, or bone cement debris. Retained debris may lead to a variety of negative health effects including damage to the joint replacement. We describe a novel technique for the better containment and easier removal of third body debris during partial hardware removal. We demonstrate hardware removal on a hip joint model in the presence and absence of water-soluble gel to depict the reduction in metal debris volume and area of spread.

Periprosthetic Fractures of the Shoulder

Periprosthetic fractures after shoulder arthroplasty are extremely challenging. Fractures may occur intraoperatively or in the postoperative setting and more commonly involve the humerus but can also affect the glenoid and the scapula. The surgeon will need skills in both fracture fixation and shoulder arthroplasty to manage these injuries. Poor bone quality, bone loss, loose components, and challenging exposure contribute to the difficulties of dealing with these fractures. Treatment options include conservative management using temporary immobilization, or surgical management, which can involve open reduction internal fixation, revision arthroplasty using a long-stem component, or combination of open reduction internal fixation and a long-stem revision implant. As the injuries are rare and highly variable, only level 4 and 5 evidence exists to help guide treatment plans.

Percutaneous screw fixation of humeral condylar fractures

The use of an indirect reduction technique and percutaneous fixation are demonstrated in fractures of the humeral condyle.