Clinical Orthopaedics and Related Research ®

A Publication of The Association of Bone and Joint Surgeons ®

Published in
Clinical Orthopaedics and Related Research®
Volume 466 | Issue 6 | Jun, 2008
Articles

Predicting Distal Femur Bone Strength in a Murine Model of Tumor Osteolysis

Kenneth A. Mann PhD, John Lee MS, Sarah A. Arrington BS, Timothy A. Damron MD, Matthew J. Allen VetMB, PhD [object Object]

Mirels’ Rating for Humerus Lesions is Both Reproducible and Valid

Andrew R. Evans MD, John Bottros MD, William Grant EdD, Benjamin Y. Chen BS, Timothy A. Damron MD Mirels’ rating system is commonly used to predict risk of fracture in patients with metastatic bone lesions to long bones, but it has not been independently validated for use in humeral bone lesions. We asked whether this system was a valid and reproducible instrument for predicting impending pathologic fractures in the humerus. We presented 17 case histories and plain radiographs of 16 patients with humeral metastases through a web-based survey to 39 physicians with varying training and experience. Participants scored each case using Mirels’ criteria and provided a fracture prediction, which was compared with actual outcome in the subset of 12 patients with three fractures not treated prophylactically. Using Mirels’ definition of impending pathologic fracture (nine points or greater), the sensitivity and specificity for determining the likelihood of pathologic humeral fracture were 14.5% and 82.9%, respectively. When we used seven or more points as the definition of impending pathologic humeral fracture, sensitivity improved to 81% but specificity was reduced to 32%. Kappa analysis suggested moderate reproducibility across groups for prediction of pathologic fracture. The Mirels rating system for humeral lesions is reproducible and valid, but low specificity at acceptable sensitivity levels as reported remains a problem as for femoral lesions.,[object Object]

Attenuated Salmonella typhimurium with IL-2 Gene Reduces Pulmonary Metastases in Murine Osteosarcoma

Brent S. Sorenson BS, MS, Kaysie L. Banton MD, Natalie L. Frykman BS, Arnold S. Leonard MD, PhD, Daniel A. Saltzman MD, PhD [object Object]

Intraarterial Chemotherapy for Extremity Osteosarcoma and MFH in Adults

Ronald R. Hugate MD, Ross M. Wilkins MD, Cynthia M. Kelly MD, Walt Madsen MD, Ioana Hinshaw MD, Anne B. Camozzi BA The neoadjuvant treatment of osteosarcoma using intravenous agents has resulted in survival rates of 55% to 77% [3, 5, 6, 20, 22, 35]. We designed a neoadjuvant chemotherapy protocol using combined intraarterial and intravenous agents to treat high-grade osteosarcoma and malignant fibrous histiocytoma of bone in an attempt to improve survival. We report the results of treating 53 adults (age 18–77 years) diagnosed with nonmetastatic extremity osteosarcoma or malignant fibrous histiocytoma. Preoperative chemotherapy consisted of intravenous doxorubicin followed by intraarterial cisplatinum administered repetitively every 3 weeks for three to five cycles, depending on tumor response assessed by serial arteriography. Dose and duration of cisplatin were adjusted for tumor size. After resection, good responders (90% or greater necrosis) underwent treatment with the same agents and poor responders were treated with alternative agents for longer duration. Minimum followup was 24 months (mean, 111 months; range, 24–235 months). Estimated Kaplan-Meier survival at 10 years was 82% and event-free survival was 79%. Forty-one patients (77%) had a good histologic response and 92% (49 of 53) underwent limb-sparing procedures. Local recurrence occurred in two patients (4%). These results compared favorably with those reported in the current literature.,[object Object]

Complications and Risk Factors for Failure of Rotationplasty: Review of 25 Patients

Chigusa Sawamura MD, Francis J. Hornicek MD, PhD, Mark C. Gebhardt MD Rotationplasty is one treatment option for femoral bone sarcomas in skeletally immature patients. This procedure enables patients to avoid phantom pain, limb length discrepancy, or loosening of an endoprosthesis, and good functional outcome has been reported. However, rotationplasty is only rarely indicated and the surgical complications or risk factors for failure of the procedure that might influence choices of treatment or patient counseling have not been well described. We reviewed 25 patients who underwent rotationplasty focusing on risk factors for failure and postoperative complications. Three of 25 patients had vascular compromise resulting in amputation. All three had vascular anastomosis and were resistant to chemotherapy with less than 95% of tumor necrosis. Two of the three patients who underwent amputation had a pathologic fracture before surgery. Late complications included one patient with a tibial fracture, two with wound complications treated with skin grafts, one with nonunion, and one with subsequent slipped capital femoral epiphysis. Rotationplasty was successfully accomplished in 22 of the 25 patients. Patients with large tumors unresponsive to chemotherapy or preoperative pathologic fracture appear at higher risk for failure of rotationplasty presumably as a result of compromise of venous drainage of the leg.,[object Object]

Does the Second-generation Intercalary Humeral Spacer Improve on the First?

Timothy A. Damron MD, Taninnit Leerapun MD, Ronald R. Hugate MD, Thomas C. Shives MD, Franklin H. Sim MD Since publication of the results of a first-generation intercalary humeral spacer, a newer design has been available that addressed the weaknesses of the first. This study evaluated the hypothesis that the second-generation lap joint junction intercalary humeral spacer reduced complications compared with the original male-female taper design. We retrospectively reviewed the charts of 32 consecutive patients who had undergone placement of an intercalary humeral spacer. Twenty-one with the male-female taper (minimum followup 0 months, mean 19.2 months) were compared with 11 with the lap joint configuration (minimum followup 0 months, mean 20.3 months). Demographic, tumor, treatment, and radiographic variables were similar between groups. We observed a lower complication rate in the lap joint group (three of 11 versus 11 of 21). The most common complications in the male-female group, neuropraxia, periprosthetic fracture, and disengagement, were not seen in the lap joint group. Aseptic loosening was more frequent in the lap joint group. There were no differences in blood loss, operative time, or Musculoskeletal Tumor Society scores between groups. We noted improvement in Musculoskeletal Tumor Society scores from preoperatively to postoperatively in both groups. Use of these implants should be reserved for patients with limited life expectancy.,[object Object]

A Comparison of Intramedullary and Juxtacortical Low-grade Osteogenic Sarcoma

Joseph H. Schwab MD, Cristina R. Antonescu MD, Edward A. Athanasian MD, Patrick J. Boland MD, John H. Healey MD, Carol D. Morris MD, MS While low-grade juxtacortical and low-grade intramedullary osteogenic sarcomas are histologically indistinguishable, they have been studied as separate entities. We retrospectively reviewed the clinical, radiographic, histologic features and treatment of 59 patients treated surgically to compare the rate of local recurrence, grade progression, and survival between low-grade intramedullary and low-grade juxtacortical osteogenic sarcoma. Forty-five (76%) patients were treated for low-grade juxtacortical osteogenic sarcoma and 14 (24%) were treated for low-grade intramedullary osteogenic sarcoma. Local recurrence rates of 7% were similar for both groups studied. The rate of distant metastases was also similar for both groups. . The rate of dedifferentiation for the entire group was 29%. Dedifferentiated lesions were treated with adjuvant chemotherapy in 16 of 17 cases. Recurrence preceded dedifferentiation in four cases. Five-year survival was over 90% in both groups. Low-grade intramedullary and low-grade juxtacortical osteogenic sarcoma were clinically indistinguishable with identical rates of local recurrence, distant metastases, dedifferentiation, and survival.,[object Object]

Analysis of the Pathology Section of the OITE Will Aid in Trainee Preparation

Frank J. Frassica MD, Derek Papp MD, Edward McCarthy MD, Kristy Weber MD We analyzed the tumor-related questions on the Orthopaedic In-Training Examinations (OITE) over a 5-year period (2002–2006). Each year approximately 27 of the 275 examination questions (10%) are tumor-related. Malignant conditions are tested more than benign ones (1.2:1). Approximately nine questions per year are immediate recall of specific entities, while eight questions tested the examinees’ ability to establish a diagnosis from imaging studies with or without biopsy material. Participants were required to establish a diagnosis from imaging studies and/or biopsy material and then choose treatment an average of seven times per examination. The examinees’ abilities in evaluation and decision making of patients was only tested an average of twice during each examination. Analysis of the content and type of question on the OITE might enable trainees to prepare more systematically. We determined the content, classified the questions, and quantified the interpretive material.

FDG-PET Imaging Can Diagnose Periprosthetic Infection of the Hip

Timothy Chryssikos BS, Javad Parvizi MD, FRCS, Elie Ghanem MD, Andrew Newberg MD, Hongming Zhuang MD, Abass Alavi MD A battery of diagnostic tests is often required to differentiate aseptic loosening from periprosthetic infection since the gold standard remains elusive. We designed a prospective study to determine the accuracy of fluorodeoxyglucose positron emission tomography (FDG-PET) imaging in diagnosing periprosthetic infection in a large multicenter setting. One hundred and thirteen patients with 127 painful hip prostheses were evaluated by FDG-PET. Images were considered positive for infection if PET demonstrated increased FDG activity at the bone-prosthesis interface of the femoral component. A combination of preoperative tests, intraoperative findings, histopathology, and clinical followup constituted the gold standard for diagnosing infection. Among the 35 positive PET scans, 28 hips were confirmed infected according to our criteria for diagnosing periprosthetic infection. Of the 92 hip prostheses with negative FDG-PET findings, 87 were considered aseptic. The sensitivity, specificity, positive and negative predictive values for FDG-PET were 0.85 (28 of 33), 0.93 (87 of 94), 0.80 (28 of 35), and 0.95 (87 of 92), respectively. The overall accuracy of this novel noninvasive imaging modality reached 0.91 (115 of 127). Based on our results, FDG-PET appears a promising and accurate diagnostic tool for distinguishing septic from aseptic painful hip prostheses.,[object Object]

A Preoperative Decolonization Protocol for Staphylococcus aureus Prevents Orthopaedic Infections

Nalini Rao MD, FACP, FSHEA, Barbara Cannella RN, Lawrence S. Crossett MD, A. J. Yates MD, Richard McGough MD Staphylococcus aureus (S. aureus) is an independent risk factor for orthopaedic surgical site infection (SSI). To determine whether a preoperative decolonization protocol reduces S. aureus SSIs, we conducted a prospective observational study of patients undergoing elective total joint arthroplasty (TJA) at our institution, with two control groups. The concurrent control group comprised patients of surgeons who did not participate in the intervention study. The preintervention control group comprised patients of participating surgeons who had undergone elective TJA during the year before the study. Patients in the intervention group were screened preoperatively for S. aureus by nasal swab cultures. S. aureus carriers were decolonized with mupirocin ointment to the nares twice daily and chlorhexidine bath once daily for 5 days before surgery. All 164 of 636 participants (26%) who tested positive completed the decolonization protocol without adverse events and had no postoperative S. aureus SSIs at 1-year followup. In contrast, 1330 concurrent control patients had 12 S. aureus infections. If these infections had occurred in the 26% of patients expected to be nasal carriers of S. aureus at a given time, the infection rate would have been 3.5% (12 of 345) in the control group. In addition, the overall infection rate of the participating surgeons, including nonstaphylococcal infections, decreased from 2.6% during the preintervention period to 1.5% during the intervention period, translating to an adjusted economic gain of $231,741 for the hospital. The data suggest a preoperative decolonization protocol reduces S. aureus SSIs in patients undergoing TJA.,[object Object]

Staphylococcus aureus Nasal Decolonization in Joint Replacement Surgery Reduces Infection

Donna M. Hacek MT (ASCP), William J. Robb MD, Suzanne M. Paule BS, James C. Kudrna MD, Van Paul Stamos MD, Lance R. Peterson MD Surgical site infections (SSIs) with Staphylococcus aureus are a recognized adverse event of hip and knee replacements. We evaluated the impact of a program to detect S. aureus nasal carriers before surgery with preoperative decolonization (using mupirocin twice daily for 5 days prior to surgery) of carriers. Nasal swab samples were obtained from patients prior to surgery from 8/1/2003 through 2/28/2005. Samples were tested using real-time PCR technology to detect S. aureus. The group that developed S. aureus SSI was compared to a combined concurrent and historical control for one year following the operation. S. aureus caused 71% of SSIs in the combined control groups. Of the 1495 surgical candidates evaluated, 912 (61.0%) were screened for S. aureus; 223 of those screened (24.5%) were positive and then decolonized with mupirocin. Among the 223 positive and decolonized patients, three (1.3%) developed a SSI. Among the 689 screen-negative patients, four (0.6%) developed SSIs for an overall rate of 0.77%. Among the 583 control patients who were not screened or decolonized, 10 (1.7%) developed S. aureus SSIs. SSIs from other organisms were 0.44% and 0.69%, respectively.,[object Object]

Multidrug-resistant Organisms in Military Wounds from Iraq and Afghanistan

Jason H. Calhoun MD, FACS, Clinton K. Murray MD, FIDSA, Maj., M. M. Manring PhD Mortality from battlefield wounds has historically declined, thanks to better surgical management, faster transport of casualties, and improved antibiotics. Today, one of the major challenges facing U.S. military caregivers is the presence of multidrug-resistant organisms in orthopaedic extremity wounds. The most frequently identified resistant strains of bacteria are Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter calcoaceticus-baumannii complex. Overuse of broad-spectrum antibiotics may be an important factor in building resistant strains. Acinetobacter infections appear to hospital-acquired and not from an initial colonization of the injury. More research is required to give military physicians the tools they require to reduce the infection rate and defeat multidrug-resistant organisms.

Infection Associated With Hematoma Formation After Shoulder Arthroplasty

Emilie V. Cheung MD, John W. Sperling MD, Robert H. Cofield MD Hematoma formation requiring operative treatment after shoulder arthroplasty may be associated with higher patient morbidity. We therefore determined whether there was an association of hematoma formation requiring operative treatment with deep infection after shoulder arthroplasty. Between 1978 and 2006, we performed 4147 shoulder arthroplasties in 3643 patients. Of these, 12 shoulders (0.3%) underwent reoperation for hematoma formation. The mean time interval from arthroplasty to surgery for the hematoma was 7 days (range, 0.5–31 days). Among nine cases in which cultures were taken, six had positive cultures; the organisms included Propionibacterium acnes in three, Staphylococcus epidermidis in one, Streptococcus species in one, and Staphylococcus epidermidis with Peptostreptococcus in one. The minimum followup was 12 months (mean, 68 months; range, 12 to 294 months). Two of the 12 patients eventually underwent resection arthroplasty for deep infection. The Neer score was excellent in one, satisfactory in six, and unsatisfactory in five patients. The data suggest hematoma formation after shoulder arthroplasty is often accompanied by positive intraoperative cultures. The surgeon should be aware of the high rate of unsatisfactory results associated with this complication as well as the possibility of developing a deep infection requiring additional surgery.,[object Object]

Procrastination of Wound Drainage and Malnutrition Affect the Outcome of Joint Arthroplasty

Fereidoon M. Jaberi MD, Javad Parvizi MD, C. Thomas Haytmanek BS, Ashish Joshi MD, MPH, James Purtill MD The association between wound drainage and subsequent periprosthetic infection is well known. However, the most appropriate treatment of wound drainage is not well understood. We retrospectively reviewed the records of 10,325 patients (11,785 procedures), among whom 300 patients (2.9%) developed persistent (greater than 48 hours postoperatively) wound drainage. Wound drainage stopped spontaneously between 2 and 4 days in 217 patients treated with local wound care and oral antibiotics. The remaining 83 patients (28%) underwent further surgery. A single débridement resulted in cessation of drainage without subsequent infection in 63 of 83 patients (76%), whereas 20 (24%) patients continued to drain and underwent additional treatment (repeat débridement, resection arthroplasty, or long-term antibiotics). Timing of surgery and the presence of malnutrition predicted failure of the first débridement. There were no differences between the success and failure groups with regard to all other examined parameters, including demographic or surgical factors.,[object Object]

Generic Tobramycin Elutes From Bone Cement Faster Than Proprietary Tobramycin

R. L. McLaren BA, A. C. McLaren MD, B. L. Vernon PhD Elution of antibiotics from antibiotic-loaded polymethylmethacrylate (AL-PMMA) increases when soluble particulate filler is added to increase the permeability of the PMMA. Antibiotic powder is in itself soluble particulate filler. For greater volume fractions of filler, greater elution occurs. The volume of generic tobramycin powder is more than 3.5 times the volume of proprietary tobramycin powder for a 1.2 g dose leading to the question: Does generic tobramycin elute from AL-PMMA faster than proprietary tobramycin? We performed elution studies on AL-PMMA beads made with 1.2 g of either generic tobramycin or proprietary tobramycin per batch of PMMA. Generic tobramycin eluted more than two times faster than proprietary tobramycin. The release mechanism started as dissolution-driven zero-order release for the generic bead set but for the proprietary bead set the released mechanism started as anomalous diffusion. The release mechanism progressed to diffusion-driven first-order release in both. The increased volume of the generic tobramycin caused more tobramycin to be available for release. The increased elution of tobramycin associated with the greater volume of generic tobramycin powder could lead to clinically higher levels of tobramycin in wound fluid and local tissues; however, the higher volume of powder could potentially cause greater mechanical compromise of the PMMA.

Chitosan Films: A Potential Local Drug Delivery System for Antibiotics

Scott P. Noel MS, Harry Courtney PhD, Joel D. Bumgardner PhD, Warren O. Haggard PhD Local antibiotic delivery is an emerging area of study designed to provide alternative methods of treatment to clinicians for compromised wound sites where avascular zones can prevent the delivery of antibiotics to the infected tissue. Antibiotic-loaded bone cement is the gold standard for drug-eluting local delivery devices but is not ideal because it requires a removal surgery. Chitosan is a biocompatible, biodegradable polymer that has been used in several different drug delivery applications. We evaluated chitosan as a potential localized drug delivery device. We specifically determined if chitosan could elute antibiotics in an active form that would be efficacious in inhibiting S. aureus growth. Elution of amikacin was 24.67 ± 2.35 μg/mL (85.68%) after 1 hour with a final cumulative release of 27.31 ± 2.86 μg/mL (96.23%) after 72 hours. Elution of daptomycin was 10.17 ± 3.83 μg/mL after 1 hour (31.61% release) and 28.72 ± 6.80 μg/mL after 72 hours (88.55%). The data from the elution study suggested effective release of amikacin and daptomycin. The activity studies indicated the eluants inhibited the growth of S. aureus. Incorporating antibiotics in chitosan could provide alternative methods of treating musculoskeletal infections.

Daptomycin Eluted From Calcium Sulfate Appears Effective Against Staphylococcus

Nathan D. Webb BS, Jonathan D. McCanless BS, Harry S. Courtney PhD, Joel D. Bumgardner PhD, Warren O. Haggard PhD The emergence of resistant strains of Gram-positive organisms in osteomyelitis creates treatment challenges. Daptomycin is an antibiotic that shows promise for treating some resistant strains of Gram-positive infections; however, it has not been widely used clinically for the treatment of osteomyelitis. We determined whether daptomycin eluted from calcium sulfate—a local delivery vehicle used for the treatment of osteomyelitis—retained activity against Gram-positive bacteria. Daptomycin was mixed with calcium sulfate hemihydrate, with both laboratory powder and a commercial kit, to form a hardened pellet. Daptomycin was eluted from calcium sulfate and retained its ability to inhibit bacterial growth of Staphylococcus aureus and Staphylococcus epidermidis for eluates gathered up to 28 days. Our preliminary data demonstrates sterilized pellets with daptomycin retained their ability to inhibit bacterial growth of certain strains of Gram-positive organisms.

Hematogenous Septic Ankle Arthritis

Paul D. Holtom MD, Lawrence Borges BS, C. G. Zalavras MD Ankle infection is a serious problem with limited published information on microbiology and associated morbidities. We describe the laboratory findings, microbiology, and occurrence of adjacent osteomyelitis in patients with hematogenous septic ankle arthritis. We retrospectively reviewed 30 patients with hematogenous septic arthritis of the ankle admitted over a 10-year period. Twenty-two patients were male and eight female. The mean age was 46 years (range, 23–67 years). C-reactive protein and erythrocyte sedimentation rate were elevated in all patients, but the peripheral white blood cell count was elevated in only 47% of patients. Staphylococcus aureus (S. aureus) was the most common pathogen, isolated in 13 (54%) of the 24 patients with positive cultures; four of these isolates (four of 24; 17% of positive cultures) were oxacillin-resistant. Four (17%) of the 24 patients with positive cultures had a mycobacterial infection. We identified adjacent osteomyelitis in 30% of patients, which was considerably associated with the presence of patient comorbidities. S. aureus is the most common pathogen in septic ankle arthritis and empiric antibiotic therapy is recommended. Adjacent osteomyelitis may be present and a high index of suspicion is necessary in patients with comorbidities.,[object Object]

Treatment of Primary Isolated Shoulder Sepsis in the Adult Patient

Scott F. M. Duncan MD, MPH, John W. Sperling MD, MBA Isolated shoulder sepsis is an uncommon clinical problem with little information in the literature on causative organisms and potential sequelae. We examined the organisms involved, surgical treatments, antibiotic treatments rendered, and complications in these cases. We retrospectively reviewed the records of 19 adult patients (19 shoulders) who underwent operative treatment of isolated shoulder sepsis from 1996 to 2005. Patient age, gender, laboratory studies, previous treatment, surgical procedures, surgical findings, cultured organism, antibiotic treatment, and complications were reviewed. The organisms included methicillin-susceptible Staphylococcus aureus (five), Streptococcus B beta hemolytic (five), Staphylococcus epidermidis (three), negative cultures (two), Streptococcus viridans (one), Escherichia coli (one), methicillin-resistant S. aureus (one), and Propionibacterium acnes (one). We treated patients with intravenous antibiotics an average of 4.2 weeks (range, 3–8 weeks). One patient underwent humeral head resection with an antibiotic spacer. Another patient died during hospitalization. Open or arthroscopic débridement in conjunction with appropriate antibiotics appears effective in eradicating infection in most adults who present with shoulder sepsis. Functional outcome is poor in those patients with irreparable rotator cuff tears and/or cartilage loss.,[object Object]

Polymicrobial Prosthetic Joint Infections: Risk Factors and Outcome

Camelia E. Marculescu MD, MSCR, J. Robert Cantey MD Limited data are available regarding the risk factors and outcome of polymicrobial prosthetic joint infection (PJIs) when compared with monomicrobial PJI. Between January 1998 and November 2006, we retrospectively identified 34 of 174 prosthetic joint infections (19%) were polymicrobial. The 2-year cumulative probability of success of treating polymicrobial and monomicrobial PJIs was 63.8% and 72.8%, respectively. Twenty-six percent, 38%, and 29% of PJIs were treated with two-stage exchange, débridement and retention, or resection arthroplasty, respectively, and the 2-year survival rate free of treatment failure in each group was 77.7% (95% confidence interval, 42.8%–94.2%), 52.7% (95% confidence interval, 28.4%–75.9%), and 64.2% (95% confidence interval, 28.7%–88.9%). Methicillin-resistant Staphylococcus aureus (26.4% versus 7.1%) and anaerobes (11.7% versus 2.8%) were more common in polymicrobial PJIs. Polymicrobial PJIs occurred in patients with a soft tissue defect/dehiscence (23.5% versus 2.8%), drainage (79.4% versus 39.2%), or prior local irradiation (8.8% versus 0.71%). We found the following factors associated with polymicrobial prosthetic joint infections: the presence of a soft tissue defect/wound dehiscence (odds ratio, 5.9), drainage (odds ratio, 5.0), and age 65 years or older (odds ratio, 2.8).,[object Object]

Increased Oxacillin Resistance in Thigh Pyomyositis in Diabetic Patients

C. G. Zalavras MD, N. Rigopoulos MD, L. Poultsides MD, M. J. Patzakis MD Thigh abscesses due to pyomyositis are uncommon. To guide empiric antibiotic therapy in diabetics we determined the rate of such infections due to oxacillin-resistant Staphylococcus aureus and Gram-negative organism infections, and whether the occurrence of oxacillin-resistant pathogens increased during the study period. We retrospectively reviewed 39 adult patients with diabetes mellitus treated for a deep thigh abscess. There were 29 men and 10 women; their mean age was 45 years. Comorbidities were present in 15 patients. S. aureus was the most common pathogen, present in 82% (32/39) of our patients. Gram-negative organisms were cultured in 14% (6/39) of patients and anaerobes in 10% (4/39). The infection was polymicrobial in 12 of 39 patients (31%). Oxacillin-resistant S. aureus comprised 25% (8/32) of infections due to S. aureus. Oxacillin-resistance increased during the last 3 years of this study from one of 18 S. aureus isolates from 1994 to 2004 to seven of 14 isolates from 2004 to 2006. In diabetic patients with thigh pyomyositis, empiric antibiotic therapy should provide broad spectrum coverage for oxacillin-resistant S. aureus, Gram-negative, as well as anaerobic organisms.,[object Object]

Consequences of Scapular Anatomy for Reversed Total Shoulder Arthroplasty

Bart Middernacht MD, Pieter-Jan Roo BSc, Georges Maele MD, PhD, Lieven F. Wilde MD, PhD The reverse total shoulder prosthesis provides successful functional outcome in many patients with rotator cuff tear arthropathy. However, scapular notching, a direct consequence of mechanical impingement between the humeral prosthesis and the glenoid, remains a major concern. We presumed a better knowledge of the anatomy of the scapula would enable design or placement modifications to minimize this phenomenon. After establishing a uniform spatial reference system using easy locatable surgical reference points and planes, we analyzed 200 dry bony scapulae and defined the glenoid and infraglenoid anatomy relative to the reference system. The bony rim of the two inferior quadrants of the glenoid forms a semicircle the center of which can be used perioperatively as an easy locatable bony reference point. The infraglenoid tubercle varies in width and length, and can interfere with the humeral part of the reverse prosthesis, creating scapular notching. To avoid notching, we suggest using a convex base plate with a smaller radius than currently used, placing it as low as possible with a 42-mm glenosphere eccentrically assembled to create a posterior offset. If prosthetic overhang cannot be obtained, we suggest removing part of the infraglenoid tubercle.

Correction of Forearm Malunion Guided by the Preoperative Complaint

Ladislav Nagy MD, Linas Jankauskas MD, Charles E. Dumont MD, PhD Diaphyseal malunion of the forearm may cause loss of pronation and supination, a painful distal radioulnar joint, and aesthetic problems. Seventeen patients (10 males, seven females; mean age, 20.6 ± 9.3 years) were operated on because of symptomatic malunion after a pediatric forearm fracture. Six patients had predominant loss of pronation (Group 1), four had predominant loss of supination (Group 2), and seven had a painful distal radioulnar joint (Group 3). An osteotomy of the radius was performed in seven patients and of both forearm bones in 10. All patients were available for clinical and radiologic assessments at a minimum followup of 6 months (mean ± standard deviation, 3.7 ± 2.3 years; range, 0.5–9.9 years). Release of the contracted interosseous membrane frequently was necessary for patients in Groups 1 and 2 to allow for correction and did not result in weakness, instability of the distal radioulnar joint, or synostosis. The overall improvement in range of motion after osteotomies for patients with a supination deficit was much better than in those with a pronation deficit. All patients in Group 3 gained a pain-free and stable distal radioulnar joint and their range of motion was unchanged. Therefore, ability to improve overall range of motion through forearm osteotomies is dependent on the patients’ preoperative complaint.,[object Object]

Small Stem Total Hip Arthroplasty in Hypoplasia of the Femur

F. Harald R. Man MD, Daniel Haverkamp MD, PhD, Harm M. Vis MD, PhD, Philip P. Besselaar MD, PhD, René K. Marti MD, PhD Total hip arthroplasty in hypoplastic femurs is technically difficult and the incidence of complications and aseptic loosening is relatively high. Cemented, uncemented, off-the-shelf, and custom-made stems all have been advocated in these cases. From 1978 to 1997, we performed 86 total hip arthroplasties in 77 patients with a hypoplastic femur using a cemented, off-the-shelf, small, curved, cobalt-chromium stem. We hypothesized results equaled those of the identical but larger-sized stems in normal-sized femora which were used as comparisons. Clinical and radiographic evaluations were performed. Minimum followup was 4.2 years (mean, 12 years; range, 4.2–20.3 years); mean Harris hip score was 88, and mean hip flexion was 104°. Six stems were revised: four because of aseptic loosening, one after a femoral fracture, and one because of malpositioning. Complications included one perforation and one fracture of the femur, one fracture, one nonunion of the greater trochanter, and one deep infection. Implant survivorship for all hips at 15 years with aseptic revision of the stem as the end point was 90% (confidence interval, 82–99) which equaled results of the larger stems. The small off-the-shelf cemented Weber stem has a high long-term survival and a low complication rate. Survival compares favorably with other small-sized total hip systems.,[object Object]

High Incidence of Squeaking in THAs with Alumina Ceramic-on-ceramic Bearings

J. C. Keurentjes MD, R. M. Kuipers MD, D. J. Wever MD, PhD, B. W. Schreurs MD, PhD Ceramic-on-ceramic bearings in THA are a popular alternative to overcome wear concerns in traditional metal-polyethylene bearings. However, squeaking is a potentially worrisome phenomenon in ceramic-on-ceramic THAs which we observed in some of our patients. We reviewed all 42 patients who underwent 43 ceramic-on-ceramic noncemented THAs during the time of the study. Squeaking, defined as a reproducible sound of squeaking, clicking, or grating, occurred in nine of 43 implants (20.9%). Standard radiographs were normal. We used CT imaging to determine cup anteversion and inclination angles, comparing the squeaking hips with those of a randomly selected control group, but found no differences. We then hypothesized specific design features (stem size, cup size, head size, and neck length of the head) would be risk factors for squeaking. We found a difference in neck length between squeaking and nonsqueaking implants. A neck length of −4 mm or shorter resulted in a relative risk of 5.56 (95% confidence interval, 1.14–27.01) for squeaking. We found a high incidence of squeaking in our population, and we believe this phenomenon is an underreported side effect of these types of bearings. A short neck length of the femoral implant was a risk factor for squeaking in ceramic-on-ceramic THA.,[object Object]

A New Technique to Reattach an Extended Trochanteric Osteotomy in Revision THA Using Suture Cord

Renuka Reddy Kuruvalli MRCS, Ronald Landsmeer MD, Ujjwal Kanti Debnath FRCS, Shivakolundu Pachai Suresh FRCS, Tudor Lloyd Thomas FRCS The extended trochanteric osteotomy (ETO) is widely used for revision total hip arthroplasty (THA). We describe a novel technique to reattach the extended trochanteric osteotomy using a suture cord. We retrospectively reviewed 20 patients who underwent revision by this technique with a minimum followup of 2 years (mean, 2.2 years; range, 2–4 years). Bony union of the osteotomy occurred in 19 patients and fibrous union in one patient who remained asymptomatic. We observed proximal migration of the osteotomy fragment in one patient (5 mm) who had bony union of the osteotomy. This technique of anchoring the osteotomy fragment directly onto the prosthetic stem using a suture cord provides a secure fixation and does not endanger the blood supply of the osteotomy. It also has the advantage of avoiding the morbidity associated with cerclage wires and the costs associated with cabling systems.,[object Object]

Simultaneous Bilateral MIS-TKA Results in Faster Functional Recovery

Ilkyu Han MD, PhD, Sang Cheol Seong MD, PhD, Sahnghoon Lee MD, PhD, Jae Ho Yoo MD, Myung Chul Lee MD, PhD Simultaneous bilateral TKAs subject patients to more arduous and painful functional recovery and increased risk of hemodynamic complications than staged bilateral TKAs. Minimally invasive TKA (MIS-TKA) reportedly results in more rapid return of function by limiting the amount of soft tissue disruption. We asked whether bilateral MIS-TKA had advantages over conventional TKA with respect to faster functional recovery. We prospectively randomized 30 patients into an MIS group (mini-medial parapatellar approach, 15 patients) and a conventional group (conventional medial parapatellar approach, 15 patients). We recorded range of motion and the time required to regain the ability to walk without assistance. Functional recovery in the MIS group was faster in rehabilitation milestones of walking without assistance and gain in range of motion. Minimally invasive TKA may benefit patients undergoing simultaneous bilateral procedures with faster functional recovery.,[object Object]

New Tendon Transfer for Correction of Drop-foot in Common Peroneal Nerve Palsy

Adolfo Vigasio MD, Ignazio Marcoccio MD, Alberto Patelli MD, Valerio Mattiuzzo MD, Greta Prestini MD Common peroneal nerve palsy has been reported to be the most frequent lower extremity palsy characterized by a supinated equinovarus foot deformity and foot drop. Dynamic tendon transposition represents the gold standard for surgical restoration of dorsiflexion of a permanently paralyzed foot. Between 1998 and 2005, we operated on a selected series of 16 patients with traumatic complete common peroneal nerve palsy. In all cases, we performed a double tendon transfer through the interosseous membrane. The posterior tibialis tendon was transferred to the tibialis anterior rerouted through a new insertion on the third cuneiform and the flexor digitorum longus was transferred to the extensor digitorum longus and extensor hallucis longus tendons. All 16 patients were reviewed at a minimum followup of 24 months (mean, 65 months; range, 24–114 months). The results were assessed using the Stanmore system questionnaire and were classified as excellent in eight, good in five, fair in two, and poor in one. Postoperative static and dynamic baropodometric evaluations also were performed. The proposed procedure, which provides an appropriate direction of pull with adequate length and fixation, is a reliable new method to restore balanced foot dorsiflexion correcting the foot and digit drop and producing a normal gait without the use of orthoses.,[object Object]

Reconstruction Technique Affects Femoral Tunnel Placement in ACL Reconstruction

Maria K. Kaseta MD, Louis E. DeFrate ScD, Brian L. Charnock AB, Robert T. Sullivan MD, William E. Garrett MD, PhD Grafts placed too anteriorly on the femur are reportedly a common cause of failure in anterior cruciate ligament reconstruction. Some studies suggest more anatomic femoral tunnel placement improves kinematics. The ability of the transtibial technique and a tibial tunnel-independent technique (placed transfemorally outside-in) to place the guide pin near the center of the femoral attachment of the anterior cruciate ligament was compared in 12 cadavers. After arthroscopic placement of the guide pins, the femur was dissected and the three-dimensional geometry of the femur, anterior cruciate ligament footprint, and positions of each guide pin were measured. The transtibial guide-pin placement was 7.9 ± 2.2 mm from the center of the footprint (near its anterior border), whereas the independent technique positioned the guide pin 1.9 ± 1.0 mm from the center. The center of the footprint was within 2 mm of an anteroposterior line through the most posterior border of the femoral cartilage in the notch and a proximodistal line through the proximal margin of the cartilage at the capsular reflection. More accurate placement of the femoral tunnel might reduce the incidence of graft failure and might reduce long-term degeneration observed after reconstruction although both would require clinical confirmation.

Ligament Reconstruction versus Distal Realignment for Patellar Dislocation

Petri Sillanpää MD, Ville M. Mattila MD, PhD, Tuomo Visuri MD, PhD, Heikki Mäenpää MD, PhD, Harri Pihlajamäki MD, PhD Recently, medial patellofemoral ligament reconstruction has been emphasized for the treatment of patellar dislocation. This study compared the results of medial patellofemoral ligament reconstruction by adductor magnus tenodesis with distal patellar realignment in patients with recurrent patellar dislocation. Additionally, the development of patellofemoral osteoarthrosis was compared for these two procedures at a median 10-year followup. Between 1994 and 2000, 47 consecutive patients were treated for recurrent patellar dislocation by adductor magnus tenodesis (18 knees) or Roux-Goldthwait procedure (29 knees). Redislocations, subjective symptoms, and functional outcomes were evaluated. Magnetic resonance imaging was performed at followup. The incidence of patellar redislocation after surgery was 7% in the adductor magnus group and 14% in the Roux-Goldthwait group. Median Kujala scores were 88 for the adductor magnus group and 86 for the Roux-Goldthwait group. Magnetic resonance imaging revealed patellofemoral articular cartilage lesions in 22 knees (73.3%) at followup, including 14 (46.6%) with full-thickness cartilage loss. Radiographs revealed patellofemoral osteoarthritis in five patients in the Roux-Goldthwait group and in none of the patients in the adductor magnus group. Adductor magnus tenodesis is a reliable method to treat recurrent patellar dislocation. The medial patellofemoral ligament reconstruction seems to reduce the risk of osteoarthrosis compared with distal realignment surgery.,[object Object]

Sclerosing Epithelioid Fibrosarcoma: Case Presentation and a Systematic Review

Christian Ossendorf MD, Gabriela M. Studer MD, Beata Bode MD, Bruno Fuchs MD, PhD In sclerosing epithelioid fibrosarcoma (SEF), a rare variant of low-grade fibrosarcoma, treatment results and therapeutic options are poorly characterized. We systematically analyzed the data of all 89 patients (43 female, 46 male; mean age, 47 years [range, 14–87 years]) reported in the literature concerning clinical presentation, histopathology, differential diagnosis, treatment, survival rates, and prognosis, and we present an additional case. Information detailing treatment, disease control, and followup was available in 60 (67%), 75 (84%), and 68 patients (76%), respectively. Case history was variable with one-third of patients reporting a painful, enlarging mass. Ten patients (13%) presented with metastases, 23 (31%) had metastases develop after diagnosis, and 28 (37%) had local recurrence. Low cellularity, mild pleomorphy, and sclerotic hyaline matrix of SEF suggest a benign clinical behavior, and cell morphology allows for the wide differential diagnosis of benign, pseudosarcomatous, and malignant proliferations. In addition to surgery, 11 patients (15%) had chemotherapy, 22 (29%) had postoperative radiation therapy, and three (4%) had a combination of both. Twenty-three patients (34%) died from their disease after a mean of 46 months, 24 (35%) were alive with disease, and 20 (31%) were alive without evidence of disease. Patients with SEF of the head and neck had the worst prognosis.,[object Object]

Copal Bone Cement Is More Effective in Preventing Biofilm Formation than Palacos R-G

Geert T. Ensing MD, PhD, Jim R. Horn MD, PhD, Henny C. Mei PhD, Henk J. Busscher PhD, Daniëlle Neut PhD Bone cements loaded with combinations of antibiotics are assumed more effective in preventing infection than bone cements with gentamicin as a single drug. Moreover, loading with an additional antibiotic may increase interconnectivity between antibiotic particles to enhance release. We hypothesize addition of clindamycin to a gentamicin-loaded cement yields higher antibiotic release and causes larger inhibition zones against clinical isolates grown on agar and stronger biofilm inhibition. Antibiotic release after 672 hours from Copal bone cement was more extensive (65% of the clindamycin and 41% of the gentamicin incorporated) than from Palacos R-G (4% of the gentamicin incorporated). The higher antibiotic release from Copal resulted in a stronger and more prolonged inhibition of bacterial growth on agar. Bacterial colony counting and confocal laser scanning microscopy of biofilms grown on the bone cements suggest antibiotic release reduced bacterial viability, most notably close to the cement surface. The gentamicin-sensitive Staphylococcus aureus formed gentamicin-resistant small colony variants on Palacos R-G and therefore Copal more effectively decreased biofilm formation than Palacos R-G.

Case Report

Peter Bonutti MD, Daniel Dethmers MD, James B. Stiehl MD Computer-assisted navigation is a surgical tool that may decrease malalignment outliers in TKA. With any new surgical technique, there is the possibility of unexpected complications that raise caution. We report two patients with displaced femoral fractures at optical tracker pin placement sites created for routine performance of navigated TKA. Our experience suggests single bicortical 5-mm pins placed in the femoral shaft have the added risk of creating a stress riser leading to the potential for fracture. Females may have a higher risk for this complication. We believe bicortical pin fixation in the femur or tibia no longer is indicated.

Case Report

Matthew B. Dobbs MD, Stephanie Boehm MD, Dorothy K. Grange MD, Christina A. Gurnett MD We treated a patient with multiple congenital joint dislocations and facial dysmorphisms consistent with Larsen syndrome. Sequencing of the FLNB gene resulted in identification of a novel, de novo 508G>C point mutation resulting in substitution of proline for a highly conserved alanine (A170P). This mutation has not been described previously but is likely causative because this alanine is highly conserved and is located in the calponin homology domain where other mutations have been described. We also report the successful use of a minimally invasive technique in achieving initial correction of bilateral congenital knee dislocations in this patient. The technique consists of serial manipulations and castings followed by an open quadriceps tenotomy. Longer followup is needed to ensure maintenance of correction and to avoid the need for more extensive surgery, which has been the traditional treatment for congenital knee dislocation associated with Larsen syndrome.

A Slow-growing Prepatellar Mass in a 31-year-old Woman

J. L. Bron MD, W. J. Mooi MD, PhD, R. Saouti MD, P. I. J. M. Wuisman MD, PhD
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