Donald W. Hohman

Antimicrobial Susceptibility of Propionibacterium acnes Isolates from Shoulder Surgery

ABSTRACT Orthopedic surgeons at our institution have noticed an increase in the number of infections due to Propionibacterium acnes, especially following operations on the shoulder. We collected P. acnes isolates from our hospital microbiology laboratory for 1 year and performed antimicrobial susceptibility testing on 28 strains from the shoulder. Antibiotics with the lowest MIC values against P. acnes (MIC50 and MIC90) included penicillin G (0.006, 0.125), cephalothin (0.047 and 0.094), and ceftriaxone (0.016, 0.045), while others also showed activity. Strains resistant to clindamycin were noted.

Hemiarthroplasty of the distal humerus for acute and chronic complex intra-articular injuries

BACKGROUND Comminuted intra-articular distal humeral fractures represent a challenging upper extremity injury. This study reviews clinical and radiographic results in patients with distal humeral hemiarthroplasty (DHH). METHODS DHH with the Latitude prosthesis (Tornier, Saint-Ismier, France) was performed in 8 patients (mean age, 64 years; age range, 33-75 years) for unreconstructible fractures of the distal humerus or salvage of failed internal fixation. Clinical outcomes were assessed with the American Shoulder and Elbow Surgeons elbow instrument; Mayo Elbow Performance Index; and Disabilities of the Arm, Shoulder and Hand questionnaire at a mean of 36 months. Radiologic assessment included radiographs and computed tomography to evaluate olecranon wear and densitometry (dual-energy x-ray absorptiometry). Range of motion, pain, and elbow satisfaction were recorded, and descriptive statistics were used for analysis. RESULTS Seven patients were available to participate in the follow-up examination. Acute cases (5 patients) scored better than salvage cases (2 patients) on the Mayo Elbow Performance Score (80 points [range, 67-95 points] and 65 points [range, 50-80 points], respectively) and Disabilities of the Arm, Shoulder and Hand score (31 points [range, 2.5-68 points] and 39 points [range, 17-62 points], respectively). The mean arc of elbow flexion and extension was 96° (range, 70°-130°), with mean flexion of 120° (range, 90°-135°) and a mean extension loss of 19° (range, 5°-30°). The mean arc of forearm rotation was 160° (range, 140°-180°). Reoperation was required in 4 patients because of painful retained hardware. Five patients reported pain with activities of daily living. CONCLUSION DHH should be used with caution until such time as longer-term outcome studies are able to show the efficacy of this procedure.

Pathologic Tibia/Fibula Fracture Through a Suture Button Screw Tract Case Report

The management of injury to the distal tibiofibular syndesmosis remains controversial in the treatment of ankle fractures. Careful selection of the fixation method and surgical technique along with appropriate postoperative management is necessary to avoid complications. Suture button fixation has been developed as a minimally invasive method of stabilizing tibiofibular diastasis with the reported benefit of accelerated recovery and rehabilitation, as well as the potential maintenance of physiologic micro motion. This form of operative management, as opposed to rigid screw fixation, likely avoids implant removal, loosening, or breakage. Although it has been shown that there is a significant incidence of soft tissue complications with the use of Tightrope (Arthrex, Naples, Florida) fixation and subsequent need for removal, there exists no reported bony complication following this method of operative management in the existing clinical trials to date. We present the case of a pathologic tibia/fibula fracture through the fixation of a previously well-healed syndesmotic disruption.

Short Term Outcomes of a Hydroxyapatite Coated Metal Backed Patella

We retrospectively evaluated the records and radiographs of 101 knees with a hydroxyapatite coated metal backed patella (HAP) and 50 knees with a cemented polyethylene patella (CP) with minimum two year clinical follow up. There were no patellar revisions during the study period. Patients in both the HAP and CP groups had similar clinical outcomes at final follow-up. Forty-five percent of patients in the HAP group had 1-2mm areas of decreased trabecular bone density around the pegs, which were not observed in the CP group, and may represent stress shielding. This uncemented HAP component has satisfactory early clinical outcomes, but long-term follow up is necessary to determine the durability of this implant.

Biomechanical comparison of femoral fixation devices for anterior cruciate ligament reconstruction using a novel testing method

BACKGROUND A novel biomechanical test method was implemented to compare the mechanical performance of two femoral fixation anchors (AperFix(r), Cayenne Medical, Scottsdale, AZ, USA or the AppianFx(r), KFx Medical, Carlsbad, CA, USA) that were utilized in anterior cruciate ligament reconstruction. METHODS Anterior cruciate ligament reconstructions were performed in 20 porcine femurs by using bovine extensor tendon grafts secured with 9 mm femoral anchors (AperFix(r) or AppianFx(r)). 10 specimens were tested for each anchor type. Infrared position sensors determined the repair construct displacements during conditioning (20 cycles at 5-50 N at 0.25 Hz), cyclic loading (1500 cycles at 50-200 N at 1 Hz), and ultimate loading (150 mm/min). Outcomes included tendon elongation, anchor displacement, stiffness, maximum load, yield load, and load at 5mm of anchor displacement. It was hypothesized that there would be no differences in the outcomes of these two devices. Independent measure t-tests compared the performance of the devices (p<0.05). FINDINGS The performance of the two anchors was comparable during the cyclic loading. During ultimate loading, a statistically higher yield load (p<0.01) and a load at 5mm of anchor displacement (p<0.01) were demonstrated for the AppianFx(r) as compared to AperFix(r). Maximum load and stiffness were not significantly different. INTERPRETATION Given the good clinical track record of the AperFix(r), the comparable, and in some cases superior, the biomechanical data presented here for the AppianFx(r) are encouraging for their clinical implementation. This study also introduced a novel test method that directly tracks the relevant construct displacements during cyclic and ultimate loading tests of the anterior cruciate ligament reconstructions.

Brace Treatment Resulting in Overcorrection of Adolescent Idiopathic Scoliosis

Brace treatment for idiopathic scoliosis in skeletally immature children is the only effective nonoperative modality for the control of curve progression. The Charleston bending brace is a custom-molded spinal orthosis that holds the patient in a completely corrected or overcorrected position while worn at night. A 9-year-old girl presented with 10° right upper thoracic and 7° left lower thoracic curves and was Risser sign 0. Nighttime treatment with a Charleston bending brace was initiated when the left lower thoracic curve progressed to 19°. After 27 months of nighttime brace wear, the lower thoracic curve was 21° to the right. Further investigation, including magnetic resonance imaging of the spine, failed to diagnose an identifiable explanation for this atypical occurrence. Conservative treatment may improve radiographic and cosmetic appearance. Overcorrection of the curve, although not likely, is possible when part-time or nighttime bracing is implemented as a means of conservative management.

Chlorhexidine Gluconate Cleansing Has No Effect on the Structural Properties of Human Patellar Tendon Allografts

PURPOSE If an anterior cruciate ligament graft somehow becomes contaminated intraoperatively, soaking it in 4% chlorhexidine gluconate has been shown to be the most popular and efficacious method for sterilization before implantation. The purpose of this study was to evaluate the effects of a chlorhexidine soak on the structural properties of human patellar tendon allografts. METHODS Sixteen human patellar tendon allografts were randomly split into 2 groups of 8. Grafts in 1 group were soaked in 4% chlorhexidine gluconate for 30 minutes, and the other grafts were kept moist in normal saline-soaked gauze. Data on preload width, preload thickness, elongation, ultimate tensile load, and stiffness were obtained through measurement and mechanical testing of the grafts. RESULTS Graft donor ages ranged from 29 to 43 years. There was no difference in the mean values of graft dimensions of the chlorhexidine-exposed group versus the normal saline-exposed group before mechanical testing (width of 9.48 mm v 9.56 mm, P = .89; thickness of 4.01 mm v 4.57 mm, P = .34). Graft elongation was not statistically different between the groups (2.52 mm v 1.43 mm, P = .27). No statistically significant difference was noted between the ultimate tensile load (2,219 N v 1,878 N, P = .36) or stiffness (274.3 N/mm v 297.0 N/mm, P = .63) of the grafts in both groups. CONCLUSIONS Structural properties of human patellar tendon allografts are not significantly affected by soaking in 4% chlorhexidine gluconate for 30 minutes. CLINICAL RELEVANCE Surgeons wishing to treat an inadvertently contaminated graft intraoperatively with 4% chlorhexidine may do so without concern that such treatment will impact graft strength.

Arthritis and Synovitis of the Shoulder

By 2030, an estimated 67 million Americans ages 18 years or older are projected to have doctor-diagnosed arthritis. Osteoarthritis (OA) affects many joints throughout the body. Although not as common as other locations such as the hip and knee, shoulder OA can be equally troubling for patients. The loss of shoulder function and therefore associated limitations of upper extremity motion can lead to depression, anxiety, activity limitations, and job performance problems. Shoulder OA and the specific causes can be grouped into primary and secondary categories. Primary or idiopathic OA has no specific identifiable cause. Secondary OA results from an identifiable cause or predisposing factor, which include but are not limited to, shoulder trauma, dislocations, or chronic rotator cuff tear. Epidemiologic data has demonstrated that glenohumeral arthrosis typically manifests after the sixth decade of life and women are more likely to have primary glenohumeral OA than men. Younger patients, however, are also occasionally afflicted, and these patients represent a unique management challenge as many of these patients wish to maintain demanding lifestyles.