Evaluation of fever in the immediate post-operative period following shoulder arthroplasty.

AIMS: To determine the incidence and timing of post-operative fevers following shoulder arthroplasty and the resulting investigations performed. PATIENTS AND METHODS: A retrospective review was conducted of all patients undergoing shoulder arthroplasty over a nine-year period. The charts of all patients with a post-operative fever (≥ 38.6°C) were reviewed and the results of all investigations were analysed. RESULTS: A total of 2167 cases (in 1911 patients) were included of whom 92 (4.2%) had a documented fever. Obese cases had a significantly greater risk for fever (relative risk 1.53; 95% confidence interval 1.02 to 2.32; p = 0.041). Investigations were performed in 43/92 cases (46.7%), with a diagnosis being made in six cases (6.6% of the total, two of whom had their diagnosis made post-discharge). CONCLUSION: Around one in 25 cases develop a fever following shoulder arthroplasty; most have no infective aetiology. These patients may be being over-investigated; investigations should be performed in patients with persistent fever or on those with an identifiable source of infection on clinical examination. Cite this article: Bone Joint J 2017;99-B:1515-19.

Comparison of radiofrequency treatment and mechanical debridement of fibrillated cartilage in an equine model.

OBJECTIVE: To compare a radiofrequency energy (RFE) prototype probe to mechanical debridement (MD) and a commercially available RFE system used for chondroplasty in the treatment of an experimentally created partial thickness cartilage lesion in horses. The study design was experimental, randomized complete block, n=8, using fifteen mature ponies. METHODS: Grade 2 to 3 cartilage lesions were prepared in both patellae. After 10 months duration, the injuries were used to study the effects of MD, a commercially available bipolar RFE device (CoVac 50; ArthroCare Corporation) and a prototype monopolar RFE device (Smith & Nephew Endoscopy). Six months after treatment the patellae were examined for chondrocyte viability and cartilage structure. RESULTS: Mean depth of cell death was significantly different among groups (controls, MD

The chemical defensome: environmental sensing and response genes in the Strongylocentrotus purpuratus genome.

Metazoan genomes contain large numbers of genes that participate in responses to environmental stressors. We surveyed the sea urchin Strongylocentrotus purpuratus genome for homologs of gene families thought to protect against chemical stressors; these genes collectively comprise the 'chemical defensome.' Chemical defense genes include cytochromes P450 and other oxidases, various conjugating enzymes, ATP-dependent efflux transporters, oxidative detoxification proteins, and transcription factors that regulate these genes. Together such genes account for more than 400 genes in the sea urchin genome. The transcription factors include homologs of the aryl hydrocarbon receptor, hypoxia-inducible factor, nuclear factor erythroid-derived 2, heat shock factor, and nuclear hormone receptors, which regulate stress-response genes in vertebrates. Some defense gene families, including the ABCC, the UGT, and the CYP families, have undergone expansion in the urchin relative to other deuterostome genomes, whereas the stress sensor gene families do not show such expansion. More than half of the defense genes are expressed during embryonic or larval life stages, indicating their importance during development. This genome-wide survey of chemical defense genes in the sea urchin reveals evolutionary conservation of this network combined with lineage-specific diversification that together suggest the importance of these chemical stress sensing and response mechanisms in early deuterostomes. These results should facilitate future studies on the evolution of chemical defense gene networks and the role of these networks in protecting embryos from chemical stress during development.

The anatomy and histology of the rotator interval capsule of the shoulder.

Forty-seven rotator interval regions from fetuses and 10 fresh-frozen rotator interval regions from adult cadavers were evaluated by gross dissection and light microscopy. Specimens from adults also were evaluated with ultrasound and magnetic resonance imaging. An analysis of 37 fetal specimens (> 14 weeks gestation) revealed two rotator interval types: Type I (9 of 37) was defined by a contiguous bridge of capsule consisting of poorly organized collagen fibers. A Type II rotator interval (28 of 37) had a complete defect covered by only a thin layer of synovium. Similar to the Type II rotator interval in the fetus, a rotator interval defect was present in six of eight specimens from adults. Histologically, the capsular tissue within the rotator interval consisted of poorly organized collagen fibers in specimens from the fetus and adult. Maximal opening of the rotator interval was seen by ultrasound with internal rotation and downward traction of the hyperextended arm in the coronal, oblique, and sagittal planes. Magnetic resonance imaging of the rotator interval region permitted anatomic evaluation. The complete absence of tissue in 28 of 37 fetuses suggests that the rotator interval defect is congenital. The authors recommend that surgeons carefully evaluate the integrity of the tissue within the rotator interval. When rotator interval closure is desired such as in patients with a persistent sulcus sign after arthroscopic stabilization, suturing the edges of more substantial tissue immediately adjacent to the boundaries of the rotator interval region would seem prudent.

Arthroscopic shoulder stabilization with suture anchors: technique, technology, and pitfalls.

Arthroscopic treatment of anterior shoulder instability has evolved significantly during the past decade. Currently, most techniques include the use of suture and suture anchors. A successful outcome is highly dependent on accurate patient selection. Preoperative evaluation, examination with the patient under anesthesia, and defining the pathoanatomy by a thorough arthroscopic examination determine the most effective treatment strategy. Technical skills include the surgeon's ability to accomplish anchor placement, suture passage, and arthroscopic knot tying. Various instruments and techniques are available to facilitate arthroscopic reconstruction. In properly selected patients and with good surgical technique, outcomes should approximate or exceed traditional open stabilization techniques.

Outpatient anterior cruciate ligament reconstruction: an analysis of charges and perioperative complications.

All outpatient anterior cruciate ligament (ACL) reconstructions using patellar tendon autograft performed at an accredited outpatient surgical center between 1994 and 1998 were prospectively studied. Hospital charges pertaining to the procedures were examined, and perioperative morbidities that might be attributed to an outpatient procedure were evaluated. The study group comprised 284 patients; average patient age at surgery was 28.7 years. Patients were subgrouped into group 1 (isolated ACL reconstructions; n=163), group 2 (ACL reconstructions and meniscal repair; n=48), and group 3 (ACL reconstructions and partial meniscectomy; n=73). Surgicenter facility charges, reoperation rate, complication rate, motion, pain management, hospital emergency room visits, hospital admission, and outpatient surgical facility visits were analyzed. Historical controls from our hospital and our initial outpatient pilot study (May 1994 through November 1995) were used as financial controls. The average surgical center charge for all patients was $3,443. On average, there was a $600 increase for all subgroups from May 1994 through November 1995 compared to December 1995 through August 1998. In the latter time interval, the fixed facility charges were $3,150, $4,075, and $4,275 for groups 1, 2, and 3, respectively. Overall, 19 (7%) patients required a reoperation including 7 (2.5%) patients who required arthroscopic debridement for symptomatic motion deficits. This study expands on our initial published report regarding hospital charges pertaining to an outpatient ACL reconstruction. Extended over another 4 years, we noted slight increases reflective of regional inflationary increases. Compared to our initial inpatient study (1988-1993), significant charge reductions were maintained. This study demonstrated a low complication rate and high patient subjective satisfaction level.

Male size, sperm transfer, and colony fitness in the western harvester ant, Pogonomyrmex occidentalis.

Mating success in the western harvester ant, Pogonomyrmex occidentalis, increases with male size. We tested the hypothesis that increased mating success increases male fitness and the fitness of colonies that make large males by comparing the sperm content of males prior to and at the conclusion of the mating swarm. The number of sperm a male initially possesses is a function of male size, and large males transfer a greater proportion of their sperm than do small males. For colonies, the payoff per unit of investment is an increasing function of male size, and investment in large males is not equivalent to investing in a larger number of small males. Allocation ratios in species that show size variation in reproductives may need to be modified by the individual fitness functions.

Thermal chondroplasty with radiofrequency energy. An in vitro comparison of bipolar and monopolar radiofrequency devices.

The purpose of this study was to examine the in vitro effects of three radiofrequency energy devices (two bipolar devices and one monopolar device) for the performance of thermal chondroplasty. Thirty-two fresh bovine femoral osteochondral sections (approximately 3 x 4 x 5 cm) from eight cows were divided into four groups (three treatment patterns and one sham-operated group with eight specimens per group). The three treatment patterns consisted of 1) radiofrequency energy delivered by a mechanical jig at 1 mm/sec in a contact mode (50 g of pressure), 2) radiofrequency energy delivered by a mechanical jig at 1 mm/sec in a noncontact mode (1 mm between probe tip and articular cartilage surface), and 3) radiofrequency energy smoothing of abraded cartilage during arthroscopic visualization. Thermal smoothing of the abraded cartilage surface was accomplished with all three devices. Significant chondrocyte death, as determined by confocal laser microscopy and cell viability staining, was observed with each device. The bipolar radiofrequency systems penetrated 78% to 92% deeper than the monopolar system. The bipolar systems penetrated to the level of the subchondral bone in all osteochondral sections during arthroscopically guided paintbrush pattern treatment. Radiofrequency energy should not be used for thermal chondroplasty until further work can establish consistent methods for limiting the depth of chondrocyte death while still achieving a smooth articular for thermal chondroplasty until further work can establish consistent methods for limiting the depth of chondrocyte death while still achieving a smooth articular surface.

Effect of bipolar radiofrequency energy on human articular cartilage. Comparison of confocal laser microscopy and light microscopy.

PURPOSE: To evaluate chondrocyte viability using confocal laser microscopy (CLM) following exposure to bipolar radiofrequency energy (bRFE) and to contrast CLM with standard light microscopy (LM) techniques. TYPE OF STUDY: In vitro analysis using chondromalacic human cartilage. METHODS: Twelve fresh chondral specimens were treated with the ArthroCare 2000 bRFE system (ArthroCare, Sunnyvale, CA) coupled with 1 of 2 types of probes and at 3 energy delivery settings (S2, S4, S6). A sham-operated group was treated with no energy delivered. Specimens were analyzed for chondrocyte viability and chondral morphology with CLM using fluorescent vital cell staining and with LM using H&E and safranin-O staining. RESULTS: LM with H&E staining showed smoothing of fine fronds of fibrillated cartilage; thickened fronds were minimally modified. Chondrocyte nuclei were present and not morphologically different than nuclei within sham-operated and adjacent untreated regions. LM with safranin-O staining showed a clear demarcation between treated and untreated regions. CLM, however, showed chondrocyte death: the depth and width of chondrocyte death increased with increasing bRFE settings. CONCLUSIONS: CLM showed that bRFE delivered through the probes investigated created significant chondrocyte death. These changes were not apparent using LM techniques.

Arthroscopic Bankart repair with the Suretac device for traumatic anterior shoulder instability in athletes.

Arthroscopic treatment of anterior shoulder instability in the athlete has evolved tremendously over the past decade. Currently, most techniques include the use of suture and suture anchors. However, the variety of arthroscopic instruments and techniques that are available shows the complexity of intra-articular tissue fixation, which includes anchor placement, suture passing, and knot tying. Stabilization using the Suretac device (Acufex Microsurgical, Mansfield, MA) simplifies tissue fixation by eliminating the need for arthroscopic suture passing and intra-articular knot tying. However, a successful outcome is highly dependent on accurate patient selection. Preoperative evaluation, examination under anesthesia, and the pathoanatomy defined by a thorough arthroscopic examination suggest the most effective treatment strategy. The ideal candidate for shoulder stabilization using the Suretac device is an athlete with a relatively pure traumatic anterior instability pattern with detachment pathology (e.g., Bankart lesion) and minimal capsular deformation.

Comparison of arthroscopic and open anterior shoulder stabilization. A two to six-year follow-up study.

BACKGROUND: Sixty-three consecutive patients with recurrent traumatic anterior shoulder instability underwent operative repair. The decision to select either arthroscopic Bankart repair or open capsular shift was based on the findings of an examination under anesthesia and the findings at the time of arthroscopy. Thirty-nine patients with only anterior translation on examination under anesthesia and a discrete Bankart lesion underwent arthroscopic Bankart repair with use of absorbable transfixing implants. Twenty-four patients with inferior translation in addition to anterior translation on examination under anesthesia and capsular laxity or injury on arthroscopy underwent an open capsular shift. METHODS: Treatment outcomes for each group were determined according to the scoring systems of Rowe et al., the American Shoulder and Elbow Surgeons, and the Short Form-36. Failure was defined as recurrence of dislocation or subluxation or the finding of apprehension. Fifty-nine (94 percent) of the sixty-three patients were examined and filled out a questionnaire at a mean of fifty-four months (range, twenty-seven to seventy-two months) following surgery. RESULTS: There were no significant differences between the two groups with regard to the prevalence of failure or any of the other measured parameters of outcome. An unsatisfactory outcome occurred after nine (24 percent) of thirty-seven arthroscopic repairs and after four (18 percent) of twenty-two open reconstructions. All cases of recurrent instability resulted from a reinjury in a contact sport or a fall less than two years postoperatively. The treatment groups did not differ with regard to patient age, hand dominance, mechanism of initial injury, duration of follow-up, or delay until surgery. Measured losses of motion were minimal and, with the exception of forward elevation, slightly more of which was lost after the open capsular shifts (p = 0.05), did not differ between the two forms of treatment. Approximately 75 percent of the patients in each group returned to their favorite recreational sports with no or mild limitations. As rated by the patients, the result was good or excellent after thirty-one (84 percent) of the arthroscopic procedures and after twenty (91 percent) of the open procedures. CONCLUSIONS: Arthroscopic and open repair techniques for the treatment of recurrent traumatic shoulder instability yield comparable results if the procedure is selected on the basis of the pathological findings at the time of surgery.

Arthroscopic versus open Bankart repair for traumatic anterior shoulder instability.

After more than 15 years of experience, arthroscopic shoulder stabilization is becoming less controversial. Historically, recurrence rates following arthroscopic stabilization have been higher than with open stabilization. Although a negligible advantage may exist in terms of expedited postoperative rehabilitation and improved postoperative recovery of motion, critics suggest that its use in contact athletes be limited. The indications for arthroscopic stabilization are expanding, in part, because of improved understanding of the pathophysiology of shoulder instability. Understanding the mechanism of recurrent instability following arthroscopic stabilization offers clues to how physicians can prevent unsatisfactory results in the future. With newer instrumentation and the ability to thermally treat capsular tissue, coexisting pathology, such as capsular plastic deformation, rotator interval lesions, and unrecognized intra-articular pathology, can now be addressed arthroscopically. The judicious use of these techniques is warranted until long-term study results become available. Ideal patients for arthroscopic Bankart repair have a discrete Bankart lesion; a robust, well-developed IGHL; no significant capsular laxity or intraligamentous injury; and an absence of concomitant intra-articular pathology. Additional findings on MR imaging or CT evidence of a discrete labral lesion and pure unidirectional anterior instability during EUA are also good prognostic indicators for arthroscopic Bankart repair. Arthroscopic criteria that render patients less appropriate for an arthroscopic repair include capsular injury, capsular laxity, a bony Bankart lesion, glenohumeral arthritis, and a rotator cuff tear. The authors' believe that either absent or patulous, poorly developed glenohumeral ligaments represent a poor prognostic indicator for a successful outcome following standard arthroscopic Bankart repair. Individuals with poor-quality tissue are more predictably managed using open capsulorrhaphy. Patients with pathologic ligamentous laxity in the absence of a Bankart lesion or any apparent intraligamentous injury to the IGHL are also good candidates for treatment with an open capsulorrhaphy. Findings determined from a thorough physical examination, EUA, and the pathology appreciated during diagnostic arthroscopy help to appropriately choose the surgical procedure that effectively addresses pathology in patients who present with recurrent traumatic anterior instability. Patient preferences and surgical experience are important determinants of procedure selection, and current arthroscopic techniques lack the versatility to uniformly address the entire spectrum of pathology that may be associated with traumatic anterior shoulder instability. Surgeons should always be prepared to convert to an open-stabilization technique if the arthroscopic technique is deficient in addressing all pathology identified at the time of surgery.

Bone marrow and recombinant human bone morphogenetic protein-2 in osseous repair.

Bone marrow stem cells and recombinant human bone morphogenetic protein-2 each has the capacity to repair osseous defects. Recombinant human bone morphogenetic proteins require the presence of progenitor cells to function. It is hypothesized that a composite graft of recombinant human bone morphogenetic protein-2 and marrow would be synergistic and could result in superior grafting to autogenous bone graft. Syngeneic Lewis rats with a 5-mm critical sized femoral defect were grafted with recombinant human bone morphogenetic protein-2 and marrow, recombinant human bone morphogenetic protein-2, marrow, syngeneic cancellous bone graft, or carrier alone (control). Serial radiographs (3, 6, 9, 12 weeks) and torque testing (12 weeks) were performed. Bone formation and union were determined. The recombinant human bone morphogenetic protein-2 and marrow composite grafts achieved 100% union at 6 weeks. Recombinant human bone morphogenetic protein alone achieved 80% union by week 12. Both groups yielded a higher union rate and superior mechanical properties than did either syngeneic bone graft (38%) or marrow (47%) alone. The superior performance of recombinant human bone morphogenetic protein-2 combined with bone marrow in comparison with each component alone strongly supports a biologic synergism. This experimentation shows the clinical importance of establishing operative site proximity for the osteoinductive factors and responding progenitor cells.

The multiple ligament injured knee.

Knee dislocations are complex cases requiring careful initial management to prevent devastating consequences caused by limb ischemia from vascular injury. Initial treatment includes gentle reduction and neurovascular assessment including an arteriogram and vascular reconstruction when necessary. Evaluation by examination and MR imaging will help define all ligamentous and associated pathology. All combined instabilities are repaired or reconstructed at the time of surgery. Early intervention within 3 weeks is preferred, as acute reconstruction is technically easier and more predictable than chronic reconstruction. Allografts are particularly helpful in these complex and time consuming knee injuries. Postoperative rehabilitation consists of initial immobilization followed by a supervised rehabilitation program emphasizing range of motion and strengthening.

Degenerative arthritis of the knee in active patients: evaluation and management.

The natural history and treatment of degenerative arthritis of the knee in active patients is a topic of great interest, with continually evolving concepts and techniques. Osteoarthritis is a spectrum of clinical entities, ranging from focal chondral defects to established arthrosis resulting from biologic and biomechanical hyaline cartilage failure. Evaluation of the active patient with knee arthritis should include a comprehensive history emphasizing symptom manifestation, activity level, and previous surgical treatment. The physical examination must include an evaluation of extremity alignment, gait patterns, and coexisting disorders of the spine and adjacent joints. Diagnostic testing is usually straightforward and should include the 45-degree flexion weight-bearing posteroanterior plain radiograph. Nonsurgical treatment modalities include rehabilitation, lifestyle modification, bracing, supportive devices, and medical management, including use of the new chondroprotective oral and injectable agents. Several surgical options exist, each with specific indications. Arthroscopic debridement can provide a positive, but often short-lived, reduction in the severity of symptoms. Tibial or femoral osteotomy may maintain the patient's active lifestyle and delay the need for arthroplasty. Unicompartmental and total knee arthroplasty can each provide reliable relief of symptoms but may not permit a return to the activities that the patient values.

Optimizing hospital reimbursement through physician awareness: a step toward better patient care.

We instituted a training program to improve the overall accuracy of medical record coding through greater physician awareness to enhance hospital reimbursement and maintain quality patient care. A physician-targeted course reviewed the prospective payment system, diagnosis-related group guidelines, ambulatory surgery reimbursement, and the relationship between accurate physician documentation and medical record coding. Annual increases in charges from prospective surgical case assignment, proper conversion of outpatient to inpatient status, and more accurate coding of inpatient comorbidities and complications led to an estimated increase in hospital charges of $1.6 million.

Knee arthritis in active individuals: matching treatment to the diagnosis.

Even among the active middle-aged population, knee arthritis is a common condition that can greatly decrease quality of life. The 45 degrees flexion weight-bearing radiograph, a crucial diagnostic step, can show joint space loss. Each patient must be treated individually, but conservative treatment with medication, activity modification, exercise, physical therapy, braces, and joint injections may be effective for long periods. Operative modalities include joint arthroscopy and reconstructive procedures such as osteotomy and joint arthroplasty. In injured knees, meniscus and cartilage transplants may prevent the development or progression of osteoarthritis. Total knee arthroplasty should be considered in active patients only when all other options have been exhausted.

Malignant fibrous histiocytoma at the site of a total hip replacement: review of the literature and case report.

Tumors developing in association with metallic implants are being reported with increasing frequency in the orthopedic literature. The authors report the tenth case of malignant fibrous histiocytoma associated with a total hip replacement. The diagnosis was made during an evaluation for rapid radiographic osteolysis surrounding the femoral component detected less than 1 year after revision of a hemiarthroplasty to a total hip replacement. The short latency period and aggressiveness of this tumor mimicking rapid osteolysis prompted a review of the literature, etiology and significance of implant-associated malignant fibrous histiocytoma.

Use of bone morphogenetic protein 2 on ectopic porous coated implants in the rat.

The ability of recombinant human bone morphogenetic protein 2 to remain osteoinductive and stimulate appositional bone formation on a porous coated implant was tested in a rat quadriceps muscle pouch. Implants with or without hydroxyapatite were used to compare the effects on bone formation of two different does (23 micrograms or 46 micrograms) of recombinant human bone morphogenetic protein 2 against controls as evidenced by contact radiography, histologic examination, and backscatter scanning electron microscopic analysis. Cylindrical plasma sprayed porous titanium implants were placed bilaterally within a muscle pouch surgically created in 48 Lewis rats. Implants treated with recombinant human bone morphogenetic protein 2 formed significantly more bone than did control implants independent of the dose or presence of hydroxyapatite. In all implants with bone formation, osteoinduction via endochondral ossification began within 7 days. By 21 days, cartilage largely was replaced by bone and marrow. The results of this ectopic, nonweightbearing in vivo assay suggest that recombinant human bone morphogenetic protein 2 remains biologically active after application to a titanium implant and may be used to enhance appositional bone formation by direct application to the implant surface.

AMPA antagonists differ from NMDA antagonists in their effects on operant DRL and delayed matching to position tasks.

The effects of NBQX (1.56-7.5 mg/kg, i.p.), a competitive antagonist at the AMPA type of glutamate receptor, were studied in two operant behavioural paradigms, differential reinforcement of low response rates (DRL), and delayed matching to position (DMTP), which have been shown to be sensitive to the antagonists of the NMDA type of glutamate receptor. Additionally, the non-competitive AMPA antagonist, GYKI 52466 (7.5-15 mg/kg, i.p.), was studied in the DRL procedure. As a positive control, the non-competitive NMDA antagonist, MK 801 (0.0125-0.1 mg/kg, i.p.) was studied in both procedures. During performance of the DRL schedule, MK 801 increased response rates in a dose dependent manner, and decreased the number of reinforcers obtained. The increase in response rates could be attributed to both a shift in the median inter-response time (IRT) to shorter intervals, and to a marked, dose dependent increase in the occurrence of bursts of responses (responses occurring within 3 s of a previous response). In contrast, NBQX and GYKI 52466 both decreased response rates in a dose dependent fashion, and did not shift the distribution of the IRTs, or increase the occurrence of burst responding. In the DMTP procedure, accuracy of matching decreased with increasing delay (up to 30 s, between presentation of sample and opportunity to respond). NBQX disrupted responding at a dose of 7.5 mg/kg, but lower doses were ineffective in influencing accuracy of performance of the discrimination. In contrast, MK 801 (0.1 and 0.2 mg/kg) reduced accuracy of matching at all delays, while tending to increase the speed of responding. These data demonstrate differences in the effects of AMPA and NMDA antagonists on performance of well trained operant behaviour.