The Effect of Platelet-rich Fibrin Matrix on Rotator Cuff Healing in a Rat Model.

The purpose of the current study was to determine if the application of platelet-rich fibrin matrix could improve regeneration of the tendon-bone insertion site in a rat rotator cuff repair model. 25 Lewis syngeneic rats underwent bilateral tenotomy and repair of the supraspinatus tendon. 10 separate rats were used for PRFM harvest. All left (control) shoulders underwent transosseous rotator cuff repair, while all right (treatment) shoulders were repaired similarly with PRFM augmentation. 9 rats were sacrificed at 2-weeks and ten at 4-weeks for biomechanical testing. 3 separate rats were sacrificed at 2-weeks and 4-weeks each for histologic analysis of the insertion site. At 2 weeks, the experimental group repairs were significantly stronger in ultimate load to failure (P=0.01), stress (P=0.03), and stiffness (P=0.03). Differences in biomechanical testing were not found between the groups at 4 weeks. Histological analysis revealed less collagen organization and cartilage formation at the insertion site in the experimental group. Semiquantitative histologic analysis confirmed our qualitative assessment of the specimens. PRFM does not recapitulate the native enthesis, but rather induces an exuberant and disordered healing response that is characterized by fibrovascular scar tissue.

Change in Driving Performance following Arthroscopic Shoulder Surgery.

The current study aimed to measure perioperative changes in driving performance following arthroscopic shoulder surgery using a validated driving simulator.21 patients who underwent arthroscopic surgery for rotator cuff or labral pathology were tested on a driving simulator preoperatively, and 6 and 12 weeks postoperatively. An additional 21 subjects were tested to establish driving data in a control cohort. The number of collisions, centerline crossings, and off-road excursions were recorded for each trial. VAS and SPADI scores were obtained at each visit.The mean number of collisions in the study group significantly increased from 2.05 preoperatively to 3.75 at 6 weeks (p<0.001), and significantly decreased to 1.95 at 12 weeks (p<0.001). Centerline crossings and off-road excursions did not significantly change from preoperative through 12 weeks, although centerline crossings were statistically different from the controls at each time point (p<0.001). Surgery on the dominant driving arm resulted in greater collisions at 6 weeks than surgery on the non-dominant driving arm (p<0.001).Preliminary data shows that driving performance is impaired for at least 6 weeks postoperatively, with a return to normal driving by 12 weeks. Driving is more profoundly affected in conditions that require avoiding a collision and when the dominant driving arm is involved.

Anticoagulant treatment of thromboembolism with intravenous heparin therapy in the early postoperative period following total joint arthroplasty.

BACKGROUND: Treatment of thromboembolism with intravenous heparin therapy in the early postoperative period after total joint arthroplasty has been associated with a high rate of complications. The purpose of the present study was to compare the rate of bleeding complications in a group of patients who required intravenous heparin therapy for the treatment of thromboembolism after total hip or knee arthroplasty with the rate in a control group of patients who received only prophylactic anticoagulation. METHODS: The postoperative courses of forty-four consecutive patients who were managed with intravenous administration of heparin and oral administration of warfarin for the treatment of a thromboembolic event following unilateral total hip or knee arthroplasty were compared with those of a control group of 376 consecutive patients who had these same procedures but did not have a thromboembolic complication. The patients in the control group were managed with prophylactic anticoagulation with use of enoxaparin. Sixty-eight percent (thirty) of the forty-four patients in the heparin group received the initial dose of heparin on or before the fourth postoperative day, and 82 percent (thirty-six) received an initial bolus of 5000 units of heparin at the initiation of therapy. RESULTS: The rate of bleeding complications was 9 percent (four of forty-four) in the heparin group, compared with 6 percent (twenty-three of 376) in the control group (p = 0.44). The mean transfusion requirement in the heparin group (1.8 units of packed red blood cells) was significantly greater than that in the control group (0.8 unit) (p < 0.0001). Three of the four patients who had a bleeding complication while receiving heparin and warfarin had coagulation parameters that were substantially higher than recommended levels. The mean duration of hospitalization in the heparin group (fifteen days) was significantly longer than that in the control group (seven days) (p < 0.0001). CONCLUSIONS: The results of the present study suggest that the use of intravenous heparin therapy for the treatment of thromboembolism in the early postoperative period after total joint arthroplasty is associated with a rate of bleeding complications that is similar to that associated with the use of prophylactic anticoagulation with use of enoxaparin alone. One should expect an increased transfusion requirement and a longer duration of hospitalization for patients who require intravenous heparin therapy for the treatment of a thromboembolic event.

The use of an injectable, biodegradable calcium phosphate bone substitute for the prophylactic augmentation of osteoporotic vertebrae and the management of vertebral compression fractures.

STUDY DESIGN: A biomechanical study comparing two materials for augmentation of osteoporotic vertebral bodies and vertebral bodies after compression fracture. OBJECTIVES: To compare an injected, biodegradable calcium phosphate bone substitute with injected polymethylmethacrylate bone cement for strengthening osteoporotic vertebral bodies and improving the integrity of vertebral compression fractures. SUMMARY OF BACKGROUND DATA: Injection of polymethylmethacrylate bone cement into fractured vertebral bodies has been used clinically. However, there is concern about thermal damage to the neural elements during polymerization of the polymethylmethacrylate bone cement as well as its negative effects on bone remodeling. Biodegradable calcium phosphate bone substitutes have been studied for enhancement of fixation in fractured vertebrae. METHODS: Forty fresh osteoporotic thoracolumbar vertebrae were used for two separate parts of this study: 1) injection into osteoporotic vertebrae: intact control (n = 8), calcium phosphate (n = 8), and polymethylmethacrylate bone cement (n = 8) groups. Each specimen then was loaded in anterior compression until failure; 2) injection into postfractured vertebrae: calcium phosphate (n = 8) and polymethylmethacrylate bone cement (n = 8) groups. Before and after injection, the specimens were radiographed in the lateral projection to determine changes in vertebral body height and then loaded to failure in anterior bending. RESULTS: For intact osteoporotic vertebrae, the average fracture strength was 527 +/- 43 N (stiffness, 84 +/- 11 N/mm), 1063 +/- 127 N (stiffness, 157 +/- 21 N/mm) for the group injected with calcium phosphate, and 1036 +/- 100 N (stiffness, 156 +/- 8 N/mm) for the group injected with polymethylmethacrylate bone cement. The fracture strength and stiffness in the calcium phosphate bone substitute group and those in the polymethylmethacrylate bone cement group were similar and significantly stronger than those in intact control group (P < 0.05). For the compression fracture study, anterior vertebral height was increased 58.5 +/- 4.6% in the group injected with calcium phosphate and 58.0 +/- 6.5% in the group injected with polymethylmethacrylate bone cement as compared with preinjection fracture heights. No significant difference between the two groups was found in anterior vertebral height, fracture strength, or stiffness. CONCLUSION: This study demonstrated that the injection of a biodegradable calcium phosphate bone substitute to strengthen osteoporotic vertebral bodies or improve vertebral compression fractures might provide an alternative to the use of polymethylmethacrylate bone cement.

Alternative bearing surfaces for total joint arthroplasty.

The biologic response to polyethylene particulate debris generated from metal-on-polyethylene bearing surfaces is thought to be largely responsible for periprosthetic osteolysis and aseptic loosening in total joint arthroplasty. As a result, there has been an interest in developing polyethylene with improved wear characteristics, as well as a renewed interest in alternative bearing surfaces for total joint arthroplasty, including ceramic-polyethylene, metal-metal, and ceramic-ceramic articulations. These alternative surfaces have demonstrated less friction and lower wear rates than metal-on-polyethylene bearing surfaces in both clinical and laboratory experiments. Clinical results, although only short- to mid-term, have been encouraging. Alternative bearing surfaces, with lower wear rates and less particulate debris formation, may have the potential to improve total joint arthroplasty survivorship by decreasing periprosthetic osteolysis, especially in younger, high-demand patients.

Bone and cartilage formation in an experimental model of distraction osteogenesis.

OBJECTIVES: (a) To develop a reliable and reproducible system for distraction osteogenesis in the rat to establish a model for future investigations of bone repair and regeneration. (b) To describe and characterize the histological events in distraction osteogenesis in the rat and to determine whether cartilage development is a normal component of the process. STUDY DESIGN: Species-specific, longitudinal time study. METHODS: Twenty rats underwent production of a middiaphyseal femoral osteotomy and application of a monolateral external fixator specifically designed for distraction. Animals were divided into five groups based on the time and extent of lengthening. RESULTS: During distraction, gap tissue showed collagen bundles and fibroblasts that were oriented longitudinally to the direction of the distraction force. Woven bone appeared to be laid down on these collagen scaffolds, and the newly formed vascular sinuses appeared to be the sites from which bone formation was initiated within the distraction gap. All groups undergoing active distraction showed intramembranous ossification in the distraction gap and endochondral ossification peripherally. However, when distraction was discontinued, endochondral ossification was observed in the gap. CONCLUSION: Distraction produces an environment in the distraction gap that suppresses the formation of cartilage. The formation of cartilage by injured periosteum, however, is obligatory and does not appear to be influenced by distraction. Bone formation within the distraction gap occurs where angiogenesis develops.

Arthroscopic treatment of an intra-articular lipoma of the knee joint.

Intra-articular lipoma is an exceedingly rare diagnosis. There have been less than 15 documented cases of an intra-articular lipoma of the knee joint. This report presents the first description of an intra-articular knee lipoma treated entirely by arthroscopic methods. Preoperative history, examination, and imaging studies are reviewed. Intraoperative findings, treatment, and postoperative evaluation are discussed as well. Symptomatic intra-articular lipoma of the knee joint can be successfully treated by arthroscopic resection. Differentiating intra-articular lipoma from lipoma arborescens, a similar but more common condition, is important with regards to optimal treatment.

Distal biceps tendon ruptures: a historical perspective and current concepts.

Distal biceps tendon rupture is a relatively rare injury most commonly seen in the dominant extremity of men between 40 and 60 years of age. It occurs when an eccentric extension force is applied to a contracting biceps muscle. The hallmark finding is a palpable defect in the distal biceps, which is accentuated by elbow flexion. Radiographic evaluation is usually not necessary. Acute surgical repair is advocated for optimal return of function by either a one-incision or a modified two-incision muscle-splitting technique. The arm is protected for 6 to 8 eight weeks after surgery. Unrestricted range of motion and gentle strengthening may begin after the 6 - 8 week protection period. Return to unrestricted activity is usually allowed by 5 months after surgery.

Synovial chondromatosis of the elbow.

Synovial chondromatosis is an uncommon disorder with rare occurrence in the elbow. Case reports in the literature for elbow synovial chondromatosis have described presenting symptoms secondary to peripheral nerve compressions or localized bursitis. We discuss a case of synovial chondromatosis of the elbow that presented as an isolated soft-tissue mass over the radial head-more suggestive of a soft-tissue tumor than of synovial chondromatosis.

Hard bearing surfaces in total hip arthroplasty.

Periprosthetic osteolysis and aseptic loosening are serious problems affecting the outcome of total joint replacement. Polyethylene particulate debris generated from metal-on-polyethylene bearing surfaces and the resulting biologic response to this debris are thought to be largely responsible. As a result, there has been a renewal of interest in hard bearing surfaces for total joint arthroplasty, including both metal-on-metal and ceramic-on-ceramic components. The new-generation all-ceramic and all-metal prostheses have demonstrated, both clinically and in the laboratory, lower friction and wear rates than metal-on-polyethylene bearing surfaces. Theoretically, lower wear rates result in less particulate debris and decreased inflammatory response. Despite excellent tribologic (lubrication, friction, wear) properties, metal-on-metal bearings raise associated issues of metal sensitivity and toxicity. For ceramic-on-ceramic bearing surfaces, issues of ceramic quality and the possibility of brittle fracture must be considered.

Long-term follow-up of the one-bone forearm procedure.

The one-bone forearm procedure can be a successful salvage option for forearm stability in selected patients and is indicated if instability and bone loss are irreparable by other means. We report a case of a dysfunctional arm secondary to radical débridement of the ulna after osteomyelitis treated successfully with a one-bone forearm procedure and followed up for 8 years.

Arthroscopic stabilization of anterior shoulder instability: a historical perspective.

The role of arthroscopic procedures in the management of glenohumeral instability continues to evolve and represents an effective alternative for addressing the pathology associated with this condition. Patient selection criteria, operative techniques, and implants all continue to evolve and have resulted in improved rates of success. Arthroscopic procedures benefit patients by avoiding the common morbidities associated with the disruption of the anterior soft tissues, including a loss of external rotation associated with open procedures. Arthroscopic procedures remain technically demanding and require skills to address all of the existing pathology. The surgeon must be prepared to address many conditions beyond the Bankart lesions including glenoid bone lesions. capsular laxity, rotator interval lesions, and SLAP lesions. In addition to the documentation of recurrence, the success of this procedure must be evaluated within the context of retained ranges of motion, recovery time, proprioceptive control, and the return to prior levels of activity. Further studies are necessary to continue to validate the efficacy of arthroscopic stabilization.

Radiographic comparison of grit-blasted hydroxyaptite and arc-deposited hydroxyapatite acetabular components. A four-year follow-up study.

High rates of aseptic loosening have been reported for microstructured hydroxyapatite-coated acetabular components. A macrostructured component surface (arc-deposition) not only improves resistance to shear forces experienced by the acetabular component and increases initial stability, but also provides channels for bone ingrowth. The purpose of this investigation was to radiographically compare a series of grit-blasted (microstructured) and arc-deposited (macrostructured) hydroxyapatite-coated acetabular components. A minimum 4-year retrospective radiographic analysis of acetabular components was performed on a total of 50 total hip arthroplasties. At 4 years, arc-deposited components were associated with fewer radiolucent lines in all Charnley zones, particularly Charnley zone III. While the 4-year results for arc-deposited hydroxyapatite acetabular components are superior to their microstructured predecessors, long-term results are still unknown.

Spontaneous rib fracture during pregnancy. A case report and review of the literature.

No studies have demonstrated a direct relationship between pregnancy and rib fracture. A case of spontaneous rib fracture in the third trimester presents the opportunity to examine factors unique to pregnancy that may predispose the patient to stress fractures of the lower ribs. A 28-year old woman in week 31 of her pregnancy presented with the chief complaint of acute onset of right upper quadrant pain. A chest radiograph demonstrated a minimally displaced fracture of the right 10th rib. During pregnancy, the enlarging uterus causes certain opposing muscular forces to act on the ribs, making them more susceptible to fracture after minimal trauma or after repeated stresses such as a chronic cough.

Orthopaedic manifestations of systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is a chronic inflammatory autoimmune disease of unknown origin. It affects multiple organ systems, but most frequently the musculoskeletal system. Highly variable manifestations include small and large joint involvement, spinal involvement, periarticular tissue symptoms, and complications associated with chronic steroid use such as osteonecrosis, osteoporosis, and stress fractures. The following review summarizes the common orthopaedic manifestations of SLE.