Douglas J. McDonald

Reasons for revision hip surgery : A retrospective review

The purpose of this study was to determine the indications for contemporary revision hip surgery in a consecutive series of patients. We retrospectively reviewed the clinical records and radiographs of 439 revision hip surgeries done between 1996 and 2003. Fifty-five percent of the surgeries were for aseptic loosening, 14% were for instability, 13% were for osteolysis around a well-fixed implant, 7% were for infection, 5% were for periprosthetic fracture, 3% were for conversion of a hemiarthroplasty, 1% was for psoas impingement, 1% was for loose recalled implants, and 1% was for implant fracture. As expected, aseptic loosening was the most common reason for revision surgery. Instability was a common reason for early revision whereas revision for osteolysis around a well-fixed implant was a more common reason for late revision.

Two-stage reconstruction of a total hip arthroplasty because of infection.

From 1969 to 1985, eighty-one patients (eighty-two hips) who had an infection after a previous total hip arthroplasty were treated with a resection arthroplasty, followed by delayed reconstruction in the form of a repeat total hip arthroplasty. For all of the reconstructions, the femoral and acetabular components were fixed to bone with cement that did not contain antibiotics. An average of 5.5 years (range, 2.0 to 13.6 years) after reimplantation, infection had recurred in eleven hips (13 per cent). The presence of retained cement at the time of the resection arthroplasty appeared to be associated with recurrent sepsis, as three of seven patients who had retained cement had a recurrent infection, compared with only eight (11 per cent) of seventy-five patients from whom the cement had been completely removed (p less than 0.01). The twenty-six patients (twenty-six hips) who had the reimplantation less than one year after the resection arthroplasty had seven recurrent infections (27 per cent), while the fifty-six patients who had reimplantation more than one year after the resection arthroplasty had only four recurrences (7 per cent) (p less than 0.001). Three of the seven patients in whom the infection was caused by gram-negative bacilli and group-D streptococcal organisms (which are considered highly virulent) and who received systemic antimicrobial therapy for less than twenty-eight days had a recurrence. In contrast, only one of the thirteen patients in whom the infection was caused by a virulent organism and who were treated for longer than twenty-eight days had a recurrence (p = 0.055). The two-stage reconstruction is an effective, safe technique even when the infection is caused by a virulent organism.

Accuracy of acetabular component position in hip arthroplasty.

BACKGROUND Acetabular component malposition is linked to higher bearing surface wear and component instability. Outcomes following total hip arthroplasty and surface replacement arthroplasty depend on multiple surgeon and patient-dependent factors. The purpose of this study was to examine the frequency in which acetabular components are placed within a predetermined target range. METHODS We evaluated postoperative anteroposterior pelvic radiographs for every consecutive primary total hip arthroplasty and surface replacement arthroplasty completed from 2004 to 2009 at a single institution. Acetabular component abduction and anteversion angles were determined using Martell Hip Analysis Suite software. We defined target ranges for abduction and anteversion for both total hip arthroplasty (30° to 55° and 5° to 35°, respectively) and surface replacement arthroplasty (30° to 50° and 5° to 25°, respectively). Surgeon and patient-related factors were analyzed for risk associated with placing the acetabular component outside the target range. RESULTS Of the 1549 total hip arthroplasties, 1435 components (93%) met our abduction target, 1472 (95%) met our anteversion target, and 1363 (88%) simultaneously met both targets. Of the 263 surface replacement arthroplasties, 233 components (89%) met our abduction target, 247 (94%) met our anteversion target, and 220 (84%) simultaneously met both targets. When previously published target ranges of abduction (30° to 45°) and anteversion (5° to 25°) angles were used, only 665 total hip replacements (43%) met the abduction target, 1325 (86%) met the anteversion target, and 584 (38%) simultaneously met both targets. Of the surface replacement arthroplasties, 181 (69%) met the abduction target, 247 (94%) met the anteversion target, and 172 (65%) simultaneously met both targets. Low-volume surgeons were 2.16 times more likely to miss target component position compared with high-volume surgeons (p = 0.002). The odds of missing the target increased by ≥ 0.2 for every 5 kg/m2 increase in body mass index. Minimally invasive approaches, diagnosis, years of surgical experience, femoral head size, and age of the patient did not affect component position. CONCLUSIONS Increased odds of component malposition were found with lower-volume surgeons and higher body mass index. No other variables had a significant effect on component placement. LEVEL OF EVIDENCE Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Chronic recurrent multifocal osteomyelitis: an evolving clinical and radiological spectrum.

Abstract Objective. To describe unusual clinical and radiological features in patients with chronic recurrent multifocal osteomyelitis (CRMO). Design and subjects. Based on radiographic and microscopic findings, three patients were prospectively diagnosed as having chronic recurrent multifocal osteomyelitis (CRMO). They form the basis of this report because of either the unusualness of the clinical presentation, hitherto undescribed associated diseases or the unusual age of presentation and sites of lesions. Results. One patient developed pyoderma gangrenosum at the site of one of the skeletal lesions and then went on to develop ulcerative proctitis. A second patient presented with a soft tissue mass, which on MRI mimicked a sarcoma. The final patient presented with lesions in the wrist and phalanges of the toes at the unusual age of 38. None of the patients was treated with steroids or antibiotics for the skeletal lesions. Steroids were administered to one patient for treatment of pyoderma gangrenosum. Conclusions. The pattern and distribution of skeletal lesions in CRMO are well recognized in the pediatric age group. The unusual clinical and/or radiological features discussed herein suggests that this is a disease that continues to evolve with a broader spectrum of features than recognized.

Myxoid liposarcoma: magnetic resonance imaging appearances with clinical and histological correlation

Myxoid liposarcoma is the most common type of liposarcoma. The magnetic resonance imaging (MRI) features of this tumor were evaluated and correlated with its clinical and histological features in seven patients to determine under what circumstances the tumor should be considered in differential diagnosis and why its signal intensity differs from those of lipoma and lipoma-like (lipoblastic) liposarcoma. In all patients the tumor presented in a lower extremity (5 thigh, 2 calf) as a painless, slowly growing mass which had been present for several months to several years. MRI examination revealed the tumors to be encapsulated, noninfiltrating, and usually septated. On T1-weighted sequences five of seven lesions (71%) showed lacy, amorphous, or linear foci of high signal within a low signal mass. These foci are believed to represent fat within the tumor and distinguish it from several other benign and malignant masses. If an indolent mass in a lower extremity demonstrates a predomiantly low signal with a few amorphous or linear high signal foci on T1-weighted sequences, one should consider the possibility of myxoid liposarcoma even if it appears benign by all other criteria. Histologic evaluation showed that myxoid liposarcomas contain less than 10% mature fat, which accounts for their low signal on T1-weighted sequences in contrast to the high signal of lipomas and lipoblastic liposarcomas.

Influence of chemotherapy on perioperative complications in limb salvage surgery for bone tumors.

From 1970 to 1986, 304 patients underwent limb salvage resections for 271 malignant and 33 benign tumors of the extremities. Reconstruction was with a prosthesis or nonbiologic spacer. Nonmechanical complications were analyzed to determine the influence of the site and method of reconstruction and the use of chemotherapy on their incidence and severity. There were 82 shoulder resections, 53 proximal femur resections, and 169 knee resections. No chemotherapy was used in 115 patients; neoadjuvant therapy was used in 128 patients and adjuvant therapy was used in 61. There were 120 complications. The most common complication was infection (36 of 304 patients; 11.8%), which led to amputation in eight patients. Resections about the knee led to more complications than the other sites, particularly if reconstructed with a large cement spacer. Patients who did not receive any chemotherapy had a 25.2% (29 of 115) incidence of complications and those who received adjuvant treatment had a 32.8% (20 of 61) incidence. This compares with a 55.4% (71 of 128) incidence in the neoadjuvant group. After neoadjuvant chemotherapy, reconstruction with an uncemented prosthesis led to the fewest complications.

Fibular reconstruction for giant cell tumor of the distal radius

The management of giant cell tumors involving the distal radius has always been a difficult problem. After resection to eradicate a primary or recurrent lesion, transplantation of a nonvascularized fibular autograft was used in 12 patients. Of these patients, ten had good to excellent functional results. The procedure can restore a functionally useful wrist.

Unsuspected metastases presenting as solitary soft tissue lesions: a fourteen-year review.

Abstract Objective. To describe a series of patients with no known primary malignancy who presented with a solitary unsuspected soft tissue metastasis masquerading as a soft tissue sarcoma, and secondarily to describe the imaging appearance of these lesions. Design. Records of two academic hospitals with active orthopedic oncology services were reviewed for patients meeting the above criteria. Clinical charts were examined, and the imaging appearance of the soft tissue lesions retrospectively reviewed. Patients. Of 1421 patients examined for soft tissue lesions, 11 were found who met the above criteria. Results. Of the 11 patients whose initial presentation was a solitary soft tissue metastasis, eight were found to have a primary lung cancer, two were diagnosed with adenocarcinoma of unknown primary, and adenocarcinoma of the colon was discovered in the remaining patient. Conclusions. The clinical presentation of a solitary soft tissue metastasis without a known primary malignancy is a rare occurrence, with an incidence of approximately 0.8%. Lung cancer is the primary neoplasm in a high percentage of these cases.

Magnetic resonance imaging in symptomatic Paget's disease

Four patients with symptomatic Pagets disease of the appendicular skeleton were evaluated by magnetic resonance (MR) imaging. The plain film findings in each case were advanced but dissimilar. All patients had progressive symptoms of pain, and one presented with excruciating pain of short duration. The radiographic features included diffuse progressive osteolysis, cortical resorption, insufficiency fractures, bowing, and cortical and trabecular thickening. In three of the patients, MRI was performed to exclude sarcoma, revealing preservation of fatty marrow signal in all phases of Pagets disease except in patients with an acute fracture (demonstrated by MRI) and sarcoma. Small, focal, linear or oval areas of low signal seen against a background of normal marrow signal on short or long TR/ TE do not mimic tumor. These findings suggest that fatty marrow signal is preserved in advanced Pagets disease unless an acute fracture or tumor is present.

The effect of quadriceps excision on functional results after distal femoral resection and prosthetic replacement of bone tumors

Although resection and reconstruction with a prosthesis is an accepted form of treatment for tumors of the distal femur, minimal effort has been made to correlate the functional result with the degree of adjacent muscle excision. From 1983 to 1986, 65 patients had distal femoral resection and prosthetic reconstruction. Ten patients had only the vastus intermedius excised (Group A), 30 patients had excision of the vastus intermedius plus either the vastus medialis or lateralis (Group B), nine patients had only the rectus femoris spared (Group C), and 16 patients had the entire quadriceps excised or conversion of the previous arthrodesis (Group D). Based on the rating system of the Musculoskeletal Tumor Society, satisfactory results were obtained in 70% of Group A patients (30% excellent and 40% good), with no poor results. In group B, 80% had good or excellent results and 7% poor results. In Group C, 78% of the patients had good results but no excellent results, whereas Group D had only 50% satisfactory results. The parameters that most often led to functional impairment were restricted motion and inadequate extensor powers. Muscle transfers, however, (flexors to extensors) were effective only in Group C patients. With proper technique and prosthetic design, satisfactory results can be achieved after distal femoral resection and prosthetic reconstruction, even after extensive quadriceps excision.