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Biomedical subjects

Scott P Steinmann

Publications and source records attributed to Scott P Steinmann.

At least 19 recordsLinked to original sources

The effect of glenoid component size on the stability of total shoulder arthroplasty.

Frequently, during the course of total shoulder arthroplasty, the measurement of the patient's native glenoid is between the available prosthetic glenoid sizes. Technically, it may be easier for the surgeon to implant a smaller glenoid component. Currently, there is no information regarding the difference in joint stability by use of glenoid components of different sizes. Stability ratio measurements were performed by use of a multiaxis testing machine with 3 different glenoid sizes (small, medium, and large) and compared by use of analysis of variance and the Tukey HSD test. Changes in the size of the glenoid component were found to have a significant effect on the stability ratio. At a load of 50 N, the stability ratio increased by 18% from the small to the medium glenoid component and by 15% from the medium to the large glenoid in the superoinferior axis. In the anteroposterior axis, the stability ratio increased by 17% from small to medium and by 10% from medium to large. The results from this study indicate a modest increase in stability when one chooses the larger of the 2 glenoid components.

Arthroplasty, Replacement↗

Locking plate fixation for proximal humeral fractures: initial results with a new implant.

Treatment of proximal humeral fractures remains controversial, with multiple reported techniques and variable results. Recently, locking plates have become available for fixation of osteopenic and comminuted fractures. This study reports our initial experience with a new locking plate designed specifically for proximal humeral fractures. We observed 16 patients until union or revision with a mean of 12 months' follow-up. Of the 16 patients, 9 had high-energy injuries. There were nine 3-part, five 2-part, and two 4-part fractures. Twelve of sixteen patients healed without complications. There were 4 nonunions; all occurred in patients with 3-part fractures with metadiaphyseal comminution, 3 of whom were heavy smokers. In patients with united fractures, mean elevation was 132 degrees and mean external rotation was 43 degrees, with mean internal rotation to T11. Locking plate fixation achieved union in 75% of patients in this series. Risk factors for delayed union or nonunion included comminution, smoking, and 3-part fractures. These fractures remain challenging despite the availability of locked plating systems.

Adolescent↗

Scaphoid fractures and nonunions: diagnosis and treatment.

BACKGROUND: Scaphoid fractures are commonly seen in orthopedic practice. An organized and thoughtful approach to diagnosis and treatment can facilitate good outcomes. However, despite optimal treatment, complications may ensue. In the setting of nonunion or an avascular proximal pole, vascularized bone grafting may be needed. METHODS AND RESULTS: In this article we review the literature regarding these injuries and describe an approach to diagnosis, treatment, and management of scaphoid fractures and nonunions. CONCLUSION: Scaphoid fractures and nonunions may present as challenging problems in practice, but a systematic and deliberate approach can facilitate optimal results.

Arthritis↗

Rotator cuff repair using an acellular dermal matrix graft: an in vivo study in a canine model.

PURPOSE: Large rotator cuff tears present a challenge to orthopaedic surgeons. Because tissue may be insufficient or of inadequate quality to undergo repair, a variety of materials have been used as adjuncts. Human dermal tissue may be processed to render it acellular, and thus less immunogenic, but with the extracellular matrix left intact, creating a collagen scaffold with favorable characteristics. Because of these traits, use in rotator cuff repair was proposed. METHODS: A canine model for a full-thickness infraspinatus tendon tear was used. Tendon was excised from the bony interface to the myotendinous junction, and a human acellular dermal matrix graft (experimental) or the autologous excised tendon (control) was used to bridge the defect. Animals were sacrificed, and shoulders were evaluated histologically and biomechanically. RESULTS: At time 0, strength of control and experimental repairs was similar. At 6 weeks, the strength of the experimental repair was half that of the control side. Strength of control specimens remained the same at 6 and 12 weeks, but by 12 weeks, the strength of the experimental repair was equal to that of the control. Histologically, cells infiltrated the control and experimental specimens by 6 weeks; chronic inflammation was consistent with surgery and repair. At 6 months, control and experimental specimens mimicked normal tendon structure grossly and histologically. CONCLUSIONS: Use of human acellular dermal matrix as a patch is a viable option in this model of large rotator cuff defects. Within 6 weeks, histologic evidence of native cell infiltration and neotendon development was observed. Within 12 weeks, the strength of the dermal matrix graft repair was equivalent to that of autologous tendon. At 6 months, control and graft specimens mimicked normal tendon structure grossly and histologically. CLINICAL RELEVANCE: This study provides in vivo animal data to support the use of this acellular dermal matrix graft for repair of full-thickness rotator cuff defects. Additional studies are indicated to determine the role of this material in the treatment of humans with rotator cuff tears.

Animals↗

Nerve injuries about the elbow.

Multiple neurovascular structures may be at risk during injuries or procedures about the elbow joint. An appreciation of the complex anatomy of the region, the appropriate evaluation procedures and processes to diagnose injury, and an understanding of treatment options are necessary for surgeons who treat elbow injuries. This article reviews the anatomy, diagnosis, and treatment options of injuries to neural structures about the elbow.

Arm Injuries↗

The anconeus flap transolecranon approach to the distal humerus.

The transolecranon approach for the treatment of distal humerus fractures and nonunions is commonly used. A complication of the standard osteotomy is denervation of the anconeus muscle, which provides dynamic stability to the lateral side of the elbow by preventing varus and posterolateral rotatory instability. This article describes the anconeus flap transolecranon (AFT) approach, which utilizes an internervous plane to preserve the anconeus muscle and a chevron-shaped osteotomy for maximal joint exposure. The approach is straightforward to perform with limited complications.

Dermatologic Surgical Procedures↗

Shoulder arthritis in the young adult: arthroscopy to arthroplasty.

Young adult patients with shoulder arthritis present challenging treatment decisions for the orthopaedic surgeon. Patients treated with shoulder arthroplasty have the youngest average age of all patients who undergo joint arthroplasty. However, in the young, active patient or in those without advanced disease, joint arthroplasty may not be appropriate. Arthroscopic treatment or interposition arthroplasty may provide symptomatic relief without radically compromising future procedures.

Arthritis↗

Arthroscopic treatment of the arthritic elbow.

Elbow arthroscopy is now being used with greater frequency to treat arthritis and contractures. The procedure is technically demanding and the potential for injury to neurovascular structures remains a concern. Potential advantages of arthroscopic treatment include improved articular visualization and decreased postoperative pain. Patients may also benefit from decreased morbidity and a faster postoperative recovery. Elbow arthroscopy can be performed for removal of loose bodies, resection of symptomatic plica, release of the capsule in patients with contracture, removal of osteophytes, treatment of synovectomy in inflammatory arthritis, treatment of osteochondritis dissecans, débridement of lateral epicondylitis, and treatment of elbow fractures.

Arthritis↗

Adult brachial plexus injuries: mechanism, patterns of injury, and physical diagnosis.

Most brachial plexus injuries involve the entire plexus. An injury to major cords or branches often contains a mixed injury pattern, with portions of the nerve being avulsed, ruptured, or stretched. An advancing Tinel's sign implies the possibility of neurologic recovery; however, the surgeon should combine this physical finding with that of electrodiagnostic studies to assess the extent of nerve injury to allow for expedient surgical intervention when necessary.

Brachial Plexus↗

Canine carpal joint fusion: a model for four-corner arthrodesis using a porous tantalum implant.

PURPOSE: Interest has focused on porous materials that promote bony ingrowth. In this study a porous tantalum implant was used as an adjunct to intercarpal stabilization in a canine model of wrist arthrodesis. METHODS: A defect was created at the junction of the radiocarpal, ulnocarpal, and fourth carpal bones, analogous to a four-corner fusion site in humans. A tantalum cylinder was press-fit and stabilized with K-wires. Controls were represented by creating the defect without implant placement. Animals were killed at 4, 8, and 12 weeks. RESULTS: Histology showed bony ingrowth as early as 4 weeks and mechanical testing showed a statistically significant increase in strength of the construct over time. Controls failed to achieve union at any time point. CONCLUSIONS: The implant served as an adjunct to stabilization of the carpus in this model of four-corner fusion, suggesting a novel application of this material in conditions in which bone graft has been required previously. This study represents a preliminary investigation of the use of a tantalum device for intercarpal stabilization; it does not compare this technique with conventional methods.

Animals↗

Adult traumatic brachial plexus injuries.

Adult traumatic brachial plexus injuries are devastating, and they are occurring with increasing frequency. Patient evaluation consists of a focused assessment of upper extremity sensory and motor function, radiologic studies, and, most important, preoperative and intraoperative electrodiagnostic studies. The critical concepts in surgical treatment are patient selection as well as the timing and prioritizing of restoration of function. Surgical techniques include neurolysis, nerve grafting, neurotization, and free muscle transfer. Results are variable, but increased knowledge of nerve injury and repair, as well as advances in microsurgical techniques, allow not only restoration of elbow flexion and shoulder abduction but also of useful prehension of the hand in some patients.

Adult↗

Gracilis free muscle transfer for restoration of function after complete brachial plexus avulsion.

OBJECT: The authors report the functional outcomes after functioning free muscle transfer (FFMT) for restoration of the upper-extremity movement after brachial plexus injury (BPI). METHODS: The authors conducted a retrospective review of 36 gracilis FFMT procedures performed in 27 patients with BPI between 1990 and 2000. Eighteen patients underwent a single gracilis FFMT procedure for restoration of either elbow flexion (17 cases) or finger flexion (one case). Nine patients underwent a double free muscle transfer for simultaneous restoration of elbow flexion and wrist extension (first muscle) and finger flexion (second muscle), combined with direct triceps neurotization. The results obtained in 29 cases of FFMT in which the follow-up period was 1 year are reported. Neurotization of the donor muscle was performed using the musculocutaneous nerve (one case), spinal accessory nerve (12 cases), or multiple intercostal motor nerves (16 cases). Two second-stage muscle flaps failed secondary to vascular insufficiency. Mean electromyography-measured reinnervation time was 5 months. At a minimum follow-up period of 1 year, five muscles achieved less than or equal to Grade M2, eight Grade M3, four Grade M4, and 12 Grade M5. Transfer for combined elbow flexion and wrist extension compared with elbow flexion alone lowered the overall results for elbow flexion strength. Seventy-nine percent of the FFMTs for elbow flexion alone (single transfer) and 63% of similarly innervated muscles transferred for combined motion achieved at least Grade M4 elbow flexion strength. CONCLUSIONS: Functioning free muscle transfer is a viable reconstructive option for restoration of upper-extremity function in the setting of severe BPI. It is possible to achieve good to excellent outcomes in terms of muscle grades with the simultaneous reconstruction of two functions by one FFMT, making restoration of basic hand function possible. More reliable results are obtained when a single FFMT is performed for a single function.

Adolescent↗

Arthroscopic resection in the management of dorsal wrist ganglions: results with a minimum 2-year follow-up period.

PURPOSE: The purpose of this report is to review the results of arthroscopic resection of dorsal wrist ganglions. METHODS: Forty-one patients with dorsal wrist ganglions had arthroscopic resection: 24 women and 17 men. The average patient age was 29.8 years. All of the patients had some or all of the following: pain, localized swelling, and limited range of motion. Along with clinical examination, 19 wrists had ultrasound or magnetic resonance imaging to confirm diagnosis. Twelve patients had previous injections with recurrence. The average follow-up time to date is 47.8 months (range, 28-97 months). RESULTS: Overall postoperative motion improved compared with preoperative values. No cases of scapholunate instability were noted. The average postoperative grip strength improved significantly. Only 2 ganglions recurred and required 2 attempts at open resection for successful eradication the ganglion. No major intraoperative or postoperative complications occurred. CONCLUSION: Arthroscopic ganglionectomy is a safe and reliable alternative to open resection.

Adolescent↗

Use of the 1,2 intercompartmental supraretinacular artery as a vascularized pedicle bone graft for difficult scaphoid nonunion.

Fourteen patients with established scaphoid nonunion were treated with vascularized pedicle bone grafting. All nonunions healed at a mean of 11.1 weeks (range, 8-16 weeks). Wrist motion was minimally affected by surgery. Intercarpal and scaphoid angles were improved after surgery, particularly in patients with preoperative humpback deformity who had previous interposition grafting. Outcome, based on a self-assessment questionnaire administered at a mean 30 months of follow-up (range, 19-53 months), showed 2 excellent, 7 good, 4 fair, and 1 poor result. Three patients showed progressive radioscaphoid arthrosis. Vascularized bone grafts are indicated in proximal pole fracture nonunions, in the presence of avascular necrosis, and after conventional grafts. Radiocarpal arthritis, if present before surgery, is a poor prognostic sign.

Adolescent↗

Shoulder arthroplasty for osteoarthritis secondary to glenoid dysplasia.

BACKGROUND: Between 1980 and 1997, six patients (seven shoulders) with glenoid dysplasia and osteoarthritis underwent shoulder arthroplasty at our institution because of moderate or severe shoulder pain. There were four hemiarthroplasties and three total shoulder arthroplasties. METHODS: All six patients (seven shoulders) were followed for a minimum of two years or until the time of revision surgery. The average duration of follow-up was 7.3 years (range, 1.3 to sixteen years). RESULTS: One shoulder treated with total shoulder arthroplasty underwent revision surgery because of infection and loosening of the glenoid component 5.8 years following the arthroplasty. Three shoulders treated with hemiarthroplasty underwent revision to total shoulder arthroplasty as a result of glenoid arthrosis at sixteen months, twenty months, and thirty-four months. In each of these shoulders, glenoid deficiency and cartilage loss were not addressed at the time of the original hemiarthroplasty. The one shoulder that did not undergo revision after hemiarthroplasty had a glenoid osteotomy performed at the time of the hemiarthroplasty. CONCLUSIONS: The data from this study suggest that glenoid deficiency and cartilage wear should be addressed in some way at the time of shoulder arthroplasty in patients with glenoid dysplasia.

Adult↗

Free vascularized corticoperiosteal bone graft for the treatment of persistent nonunion of the clavicle.

Radiation-induced necrosis or infection can result in a persistent nonunion of the clavicle. We describe 3 cases in which a free vascularized corticoperiosteal flap was harvested from the medial aspect of the femoral condyle and transferred to the fractured clavicle by use of microvascular anastomoses. Healing was confirmed by tomography in all 3 patients. The function of the upper extremity was remarkably improved at final follow-up. Vascularized free corticoperiosteal bone flaps are an option in clavicle fracture treatment. The technique of periosteal grafting is ideally suited to chronic nonunions with poor chances of healing on their own. Rapid subperiosteal new bone and improved local blood flow serve to correct many of those changes attributed to necrosis of bone.

Adult↗