Sara L. Edwards

Two-part surgical neck fractures of the proximal part of the humerus. A biomechanical evaluation of two fixation techniques.

BACKGROUND Successful internal fixation of fractures of the surgical neck of the humerus can be difficult to achieve because of osteopenia of the proximal aspect of the humerus. The purpose of this study was to compare the biomechanical stability of a proximal humeral intramedullary nail and a locking plate for the treatment of a comminuted two-part fracture of the surgical neck in a human cadaver model. METHODS Twenty-four cadaveric humeri were instrumented with use of either a titanium proximal humeral nail (PHN) or a 3.5-mm locking compression plate for the proximal part of the humerus (LCP-PH). The specimens were matched by bone mineral density and were separated into four experimental groups with six humeri in each: PHN bending, LCP-PH bending, PHN torsion, or LCP-PH torsion. Comminuted fractures of the surgical neck were simulated by excising a 10-mm wedge of bone. Bending specimens were cyclically loaded from 0 to 7.5 Nm of varus bending moment at the fracture site. Torsion specimens were cyclically loaded to +/-2 Nm of axial torque. The mean and maximum displacement in bending, mean and maximum angular rotation in torsion, and stiffness of the bone-implant constructs were compared. RESULTS In bending, the LCP-PH group demonstrated significantly less mean displacement of the distal fragment than did the PHN group over 5000 cycles (p = 0.002). In torsion, the LCP-PH group demonstrated significantly less mean angular rotation than did the PHN group over 5000 cycles (p = 0.04). A significant number of specimens in the PHN group failed prior to reaching 5000 cycles (p = 0.04). The LCP-PH implant created a significantly stiffer bone-implant construct than did the PHN implant (p = 0.007). CONCLUSIONS The LCP proximal humeral plate demonstrated superior biomechanical characteristics compared with the proximal humeral nail when tested cyclically in both cantilevered varus bending and torsion. The rate of early failure of the proximal humeral nail could reflect the high moment transmitted to the locking proximal screw-bone interface in this implant. CLINICAL RELEVANCE The high failure rate in torsion of the proximal humeral nail-bone construct is concerning, and, with relatively osteoporotic bone and early motion, the results could be poor.

Nonoperative Treatment of Superior Labrum Anterior Posterior Tears Improvements in Pain, Function, and Quality of Life

Background: Although there are multiple reports documenting successful outcomes with operative treatment of superior labrum anterior posterior (SLAP) tears, there are few reports on the results of nonoperative treatment. Hypothesis: Nonoperative treatment of SLAP tears will result in improved outcomes over pretreatment values using validated, patient-derived outcome instruments. Study Design: Case series; Level of evidence, 4. Methods: A total of 371 patients with a diagnosis of labral tear at our institution were mailed a questionnaire that included the following validated, patient-derived outcome assessment instruments: Short Form 36 (SF-36), European Quality of Life measure (EuroQol), visual analog pain scale (VAS), American Shoulder and Elbow Surgeons (ASES) score, and simple shoulder test (SST). Sixty-six surveys did not reach the patients because of incorrect addresses, and 50 surveys were returned, for a 16.4% (50 of 305) response rate. Of the patients with a clinically documented SLAP lesion (positive O’Brien test, pain at the bicipital groove, and positive magnetic resonance imaging) and sufficient follow-up data (minimum 1 year), 39 patients who met the criteria returned the survey and 19 had nonoperative treatment. Twenty patients (51%) from the overall surveyed group were considered nonoperative treatment failures and had arthroscopic surgical reconstruction. Nonoperative treatment consisted of nonsteroidal anti-inflammatory drugs and a physical therapy protocol focused on scapular stabilization exercises and posterior capsular stretching. Statistical analysis was performed using the paired t test; values of P < .05 were considered significant. Results: At an average follow-up of 3.1 years, function improved significantly (ASES function 30.8 to 45.0 [P < .001]; ASES total 58.5 to 84.7 [P = .001], SST 8.3 to 11.0 [P = .02]) in those patients with successful nonoperative treatment. Quality of life also improved after treatment (EuroQol 0.76 to 0.89, P = .009). Pain relief was significant, as VAS pain scores decreased from 4.5 to 2.1 (P = .043). All patients with successful nonoperative treatment returned to sports. Seventy-one percent of all athletes were able to return to preparticipation levels, but only 66% of overhead athletes returned to their sport at the same or higher level. Conclusion: Using validated, patient-derived outcome instruments, the present study shows that successful nonoperative treatment of superior labral tears results in improved pain relief and functional outcomes compared with pretreatment assessments. Although 20 patients (51%) in this group elected surgery and may be considered nonoperative treatment failures, those patients with successful nonoperative treatment had significant improvements in pain, function, and quality of life. Return to sports was comparable with patients with successful surgical treatment, although return to overhead sports at the same level was difficult to achieve (66%). Based on these findings, a trial of nonoperative treatment may be considered in patients with the diagnosis of isolated superior labral tear. In overhead athletes and in those patients where pain relief and functional improvement is not achieved, surgical treatment should be considered.

Infection After Shoulder Surgery

Abstract Infection after shoulder surgery is rare but potentially devastating. Normal skin flora, including Staphylococcus aureus, Staphylococcus epidermidis, and Propionibacterium acnes, are the most commonly isolated pathogens. Perioperative measures to prevent infection are of paramount importance, and clinical acumen is necessary for diagnosis. Superficial infections may be managed with local wound measures and antibiotics; deep infections require surgical débridement in combination with antibiotic treatment. Treating physicians must make difficult decisions regarding antibiotic duration and the elimination of the offending organisms by resection arthroplasty, direct implant exchange, or staged revision arthroplasty. Eradication of a deep infection is usually successful, but the course of treatment is often protracted, and tissue destruction and scar may adversely affect functional outcome.

Treatment of glenohumeral osteoarthritis.

This clinical practice guideline is based on a systematic review of published studies on the treatment of glenohumeral osteoarthritis in the adult patient population. Of the 16 recommendations addressed, nine are inconclusive. Two were reached by consensus-that physicians use perioperative mechanical and/or chemical venous thromboembolism prophylaxis for shoulder arthroplasty patients and that total shoulder arthroplasty not be performed in patients with glenohumeral osteoarthritis who have an irreparable rotator cuff tear. Four options were graded as weak: the use of injectable viscosupplementation; total shoulder arthroplasty and hemiarthroplasty as treatment; avoiding shoulder arthroplasty by surgeons who perform fewer than two shoulder arthroplasties per year (to reduce the risk of immediate postoperative complications); and the use of keeled or pegged all-polyethylene cemented glenoid components. The single moderate-rated recommendation was for the use of total shoulder arthroplasty rather than hemiarthroplasty. Management of glenohumeral osteoarthritis remains controversial; the scientific evidence on this topic can be significantly improved.

Biologic and pharmacologic augmentation of rotator cuff repairs.

As rotator cuff repair techniques have improved, failure of the tendon to heal to the proximal humerus is less likely to occur from weak tendon-to-bone fixation. More likely causes of failure include biologic factors such as intrinsic tendon degeneration, fatty atrophy, fatty infiltration of muscle, and lack of vascularity of the tendons. High failure rates have led to the investigation of biologic augmentation to potentially enhance the healing response. Histologic studies have shown that restoration of the rotator cuff footprint during repair can help reestablish the enthesis. In animal models, growth factors and their delivery scaffolds as well as tissue engineering have shown promise in decreasing scar tissue while maintaining biomechanical strength. Platelet-rich plasma may be a safe adjuvant to rotator cuff repair, but it has not been shown to improve healing or function. Many of these strategies need to be further defined to permit understanding of, and to optimize, the biologic environment; in addition, techniques need to be refined for clinical use.

Infant and child motor development

Identifying infant and child developmental delay is a skill important for orthopaedic surgeons to master because they often are asked to distinguish between normal and abnormal movement. An emphasis has been placed on early detection and referral for intervention, which has been shown to enhance the lives of the infant or child and his or her family. Appropriate recognition of delay is necessary for referral to early intervention services, which serve to help these children overcome or improve motor dysfunction and to help families grow more confident in caring for children with special needs. We define early intervention, discuss normal and abnormal motor development, and provide useful examination tools to assess motor development.

Biomechanical Comparison of 3 Methods to Repair Pectoralis Major Ruptures

Background: Pectoralis major ruptures are closely associated with weight lifting and participation in sports. The anatomy of the pectoralis major tendon is unique with an elongated thin footprint requiring multiple points of fixation to restore the native anatomy. Multiple options exist for tendon repairs, but the strongest construct has yet to be identified. Purpose: The intent of this study was to compare the load to failure of bone trough, cortical button, and suture anchor repairs of the pectoralis major tendon in the extended and abducted position. Study Design: Controlled laboratory study. Methods: Thirty fresh-frozen cadaveric shoulders were divided equally into 3 groups based on the repair technique to be performed. Bone mineral density of the surgical neck of the proximal humerus was assessed before each repair. Bone trough, suture anchor, and cortical button repairs were performed as dictated by computerized randomization. Each specimen was loaded to failure and mode of failure was noted. Results: The majority of failures occurred through the suture used for tendon repair. One specimen in the bone trough group failed via fracture of the proximal humerus. The suture anchor group failed at the implant in 5 of 9 specimens and through the suture in 4 of 9 specimens. Load to failure was greatest in bone trough repairs at 596 N, followed by cortical button at 494 N, and finally suture anchor repairs with 383 N. Load to failure was significantly greater in the bone trough group when compared with suture anchor repairs (P = .007). No correlation was found between bone mineral density and load to failure. Conclusion: Bone trough repair of the pectoralis major tendon was stronger than suture anchor repair. Clinical Relevance: Identification of the strongest repair may help guide surgical repair.

The anterior deltoid's importance in reverse shoulder arthroplasty: a cadaveric biomechanical study.

BACKGROUND Frequently, patients who are candidates for reverse shoulder arthroplasty have had prior surgery that may compromise the anterior deltoid muscle. There have been conflicting reports on the necessity of the anterior deltoid thus it is unclear whether a dysfunctional anterior deltoid muscle is a contraindication to reverse shoulder arthroplasty. The purpose of this study was to determine the 3-dimensional (3D) moment arms for all 6 deltoid segments, and determine the biomechanical significance of the anterior deltoid before and after reverse shoulder arthroplasty. METHODS Eight cadaveric shoulders were evaluated with a 6-axis force/torque sensor to assess the direction of rotation and 3D moment arms for all 6 segments of the deltoid both before and after placement of a reverse shoulder prosthesis. The 2 segments of anterior deltoid were unloaded sequentially to determine their functional role. RESULTS The 3D moment arms of the deltoid were significantly altered by placement of the reverse shoulder prosthesis. The anterior and middle deltoid abduction moment arms significantly increased after placement of the reverse prosthesis (P < .05). Furthermore, the loss of the anterior deltoid resulted in a significant decrease in both abduction and flexion moments (P < .05). CONCLUSION The anterior deltoid is important biomechanically for balanced function after a reverse total shoulder arthroplasty. Losing 1 segment of the anterior deltoid may still allow abduction; however, losing both segments of the anterior deltoid may disrupt balanced abduction. Surgeons should be cautious about performing reverse shoulder arthroplasty in patients who do not have a functioning anterior deltoid muscle.

Heat Generated With Pegged or Keeled Glenoid Components Fixed With Defined Amounts of Cement

Glenoid component loosening is a common complication of total shoulder arthroplasty and has been associated with the progression of radiolucent lines at the glenoid bone-cement interface. Generation of heat during the exothermic reaction of cement curing may cause osteonecrosis of bone, potentially leading to the development of radiolucent lines. The purpose of this study was to measure the heat generated with various defined amounts of cement used for glenoid component fixation.Ten fresh-frozen cadaver scapulas were randomized to receive a keeled or pegged component with 1, 2, 3, 5, or 7 g of cement for fixation. An infrared camera was used to record the surface temperature generated during the cement curing process to an accuracy of ±2.0°C. Computed tomography was used to evaluate the cement mantle. The maximum temperatures generated did not exceed the critical value for osteonecrosis (56°C) in any of the specimens. The 4 specimens without a complete mantle were those fixed with a smaller quantity of cement (1, 2, or 3 g), and the largest cement mantle thicknesses were observed with the use of 7 g of cement.Up to 7 g of cement can be used without significant concern for thermal necrosis. Incomplete cement mantles were observed when ≤3 g of cement was used for fixation. Our results suggest that surgeons should use >3 g of cement to avoid incomplete cement mantles and that up to 7 g of cement can safely be used for glenoid fixation.

Incidence of Injury Based on Sports Participation in High School Athletes

ABSTRACT Objectives: Youth participation in competitive athletics has significantly increased in the past two decades. There has also been a recent rise in the number of sports injuries that physicians are seeing in young athletes. The objective of this study was to assess the likelihood of sports injuries based on several risk factors in a general sample of athletes at a suburban-area high school. Methods: This was a cross-sectional study. An online survey was distributed to 2,200 student-athletes at a local high school with a mean age of 15.9 years. Four hundred eighty four (22%) complete responses were received. Data collected in the survey included demographics, frequency of sports participation, level of participation, types of sports played, participation in cross-training, injuries incurred, use of non-steroidal anti-inflammatory drugs, and treatment for sports injuries. Results: Athletes played an average of 1.6 different sports. The average number of hours of participation in sports annually was 504.3 ± 371.6 hours. The average total number of sports injuries experienced by athletes in our study was 1.7 per participant. 80.8% of respondents reported having sustained at least one sports injury. A higher total number of hours per year of sports participation and playing a contact sport were significantly associated with more reported lifetime sports injuries. Older age, playing a contact sport, and playing on a travel/club team were associated with students using NSAIDs for sports injuries. Older age, playing a contact sport, and doing cross training are also associated with having had surgery for a sports injury. Conclusions: Although more hours of participation and playing a contact sport may lead to an increased number of injuries, this risk must be weighed against the myriad of benefits that sports provide for young athletes.