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ABSTRACT: BACKGROUND: Computer-aided surgery aims to improve implant alignment in TKA but has only been adopted by a minority for routine use. A novel approach, navigated freehand bone cutting (NFC), is intended to achieve wider acceptance by eliminating the need for cumbersome, implant-specific mechanical jigs and avoiding the expense of navigation. QUESTIONS/PURPOSES: We determined cutting time, surface quality, implant fit, and implant alignment after NFC of synthetic femoral specimens and the feasibility and alignment of a complete TKA performed with NFC technology in cadaveric specimens. METHODS: Seven surgeons prepared six synthetic femoral specimens each, using our custom NFC system. Cutting times, quality of bone cuts, and implant fit and alignment were assessed quantitatively by CT surface scanning and computational measurements. Additionally, a single surgeon performed a complete TKA on two cadaveric specimens using the NFC system, with cutting time and implant alignment analyzed through plain radiographs and CT. RESULTS: For the synthetic specimens, femoral coronal alignment was within ± 2° of neutral in 94% of the specimens. Sagittal alignment was within 0° to 5° of flexion in all specimens. Rotation was within ± 1° of the epicondylar axis in 97% of the specimens. The mean time to make cuts improved from 13 minutes for the first specimen to 9 minutes for the fourth specimen. TKA was performed in two cadaveric specimens without complications and implants were well aligned. CONCLUSIONS: TKA is feasible with NFC, which eliminates the need for implant-specific instruments. We observed a fast learning curve. CLINICAL RELEVANCE: NFC has the potential to improve TKA alignment, reduce operative time, and reduce the number of instruments in surgery. Fewer instruments and less sterilization could reduce costs associated with TKA.
Clinical Orthopaedics and Related Research 09/2012; · 2.53 Impact Factor
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ABSTRACT: Background An increased incidence of osteonecrosis of the femoral head has been reported in patients infected with human immunodeficiency virus (HIV). The purpose of this study was to review the pathologic specimens of HIV-positive patients who had undergone total hip arthroplasty (THA) and compare them with those of THA patients who were HIV-negative. The surgical outcomes of these HIV-positive patients were also reviewed. Methods 40 HIV-positive patients who underwent 54 THAs at our institution were identified. The primary pathologic diagnosis for the femoral heads of these patients was osteonecrosis in 35 cases, degenerative joint disease in 11 cases, and other diagnoses in 8 cases. Results There was a higher incidence of osteonecrosis in HIV-positive patients. At the most recent follow-up, 4 patients had died and 1 patient had a significant Staphylococcus aureus infection of the hip. Interpretation There was a significant difference in the pathologic diagnoses of the HIV-positive group and the HIV-negative group, implicating HIV infection as a risk factor for osteonecrosis. Also, the risk of infectious complications is lower in our study than previously reported in other studies of HIV-positive patients who have undergone THA.
07/2009; 76(2):198-203.
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American journal of orthopedics (Belle Mead, N.J.) 03/2009; 38(2):E31-3.
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ABSTRACT: The Van Nes rotationplasty is a useful limb-preserving procedure for skeletally immature patients with distal femoral or proximal tibial malignancy. The vascular supply to the lower limb either must be maintained and rotated or transected and reanastomosed. We asked whether there would be any difference in the ankle brachial index or complication rate for the two methods of vascular management. Vessels were resected with the tumor in seven patients and preserved and rotated in nine patients. One amputation occurred in the group in which the vessels were preserved. Four patients died secondary to metastatic disease diagnosed preoperatively. The most recent ankle brachial indices were 0.96 and 0.82 for the posterior tibial and dorsalis pedis arteries, respectively, in the reconstructed group. The ankle brachial indices were 0.98 and 0.96 for the posterior tibial and dorsalis pedis arteries, respectively, in the rotated group. Outcomes appear similar using both methods of vascular management and one should not hesitate to perform an en bloc resection when there is a question of vascular involvement.
Clinical Orthopaedics and Related Research 06/2008; 466(5):1210-6. · 2.53 Impact Factor
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ABSTRACT: The objective of this study was to determine the ultimate outcome of patients who experienced immediate postoperative instability after primary total hip arthroplasty using regional anesthesia. Thirty-one patients whose radiographs demonstrated dislocation or subluxation immediately after total hip arthroplasty were evaluated as to the ultimate outcome of hip function and stability. Once a dislocation has occurred, the risk of redislocation is high. In this study, of the 29 patients who did not have revisions immediately after surgery, 3 (10.3%) have had recurrent dislocation and 1 (3.5%) has had a subluxation event. Recurrent instability or the need for revision surgery is significantly greater when compared with those patients who have no evidence of postoperative instability.
The Journal of Arthroplasty 02/2007; 22(1):79-82. · 2.38 Impact Factor
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ABSTRACT: Various studies have questioned the benefit of repairing the posterior structures after total hip arthroplasty because their integrity can appear disrupted at followup. However, these studies did not directly examine the posterior structures. We hypothesized that repaired posterior structures remain intact after total hip arthroplasty, and that their integrity could be evaluated by ultrasonography. We performed evaluations in the hips of 18 patients that had either the short external rotators and capsule repaired, or the capsule, short external rotators, and quadratus femoris repaired. Nine patients in each group were examined using ultrasonography at 6 weeks and 3 months postoperatively. The short external rotators and capsule were intact in 89% of patients in both groups at 6 weeks and 3 months postoperatively. At both time points, the quadratus femoris had continuity in 44% of hips with the standard posterior repair and 78% of hips with the enhanced posterior repair (p = 0.15). Ultrasonography can be used to effectively assess the integrity of the posterior repair after total hip arthroplasty. The posterior structures were intact in the majority of patients 3 months after total hip arthroplasty.
Clinical Orthopaedics and Related Research 07/2006; 447:43-7. · 2.53 Impact Factor
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ABSTRACT: The purpose of this study was to compare the cement mantles of 100 consecutive collared cemented stems with those of 100 consecutive collarless cemented stems of similar design. All stems were implanted by the same surgeon. Two independent examiners retrospectively reviewed the results. Between the 2 femoral stem types, there was no statistical difference in proximal medial cement mantle size, stem orientation, canal-fill percentage, or cement mantle grade, and there was no radiographic difference in cement mantle quality or stem position.
American journal of orthopedics (Belle Mead, N.J.) 06/2006; 35(5):235-6.
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ABSTRACT: An increased incidence of osteonecrosis of the femoral head has been reported in patients infected with human immunodeficiency virus (HIV). The purpose of this study was to review the pathologic specimens of HIV-positive patients who had undergone total hip arthroplasty (THA) and compare them with those of THA patients who were HIV-negative. The surgical outcomes of these HIV-positive patients were also reviewed.
40 HIV-positive patients who underwent 54 THAs at our institution were identified. The primary pathologic diagnosis for the femoral heads of these patients was osteonecrosis in 35 cases, degenerative joint disease in 11 cases, and other diagnoses in 8 cases.
There was a higher incidence of osteonecrosis in HIV-positive patients. At the most recent follow-up, 4 patients had died and 1 patient had a significant Staphylococcus aureus infection of the hip.
There was a significant difference in the pathologic diagnoses of the HIV-positive group and the HIV-negative group, implicating HIV infection as a risk factor for osteonecrosis. Also, the risk of infectious complications is lower in our study than previously reported in other studies of HIV-positive patients who have undergone THA.
Acta Orthopaedica 05/2005; 76(2):198-203. · 2.17 Impact Factor
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ABSTRACT: Femoral impaction allografting has been done with and without variations of the original description. The purpose of this study was to review Harris hip scores, radiographs, and complications in patients in whom we used the original technique without significant modifications. Preoperative and postoperative hip scores and radiographic data were available at a mean of 4.7 years for 43 of 44 hips that had femoral component impaction allografting with a collarless, polished, tapered stem. Bone stock was classified according to the Endo-Klinik classification. Survivorship, using femoral reoperation for symptomatic aseptic loosening as the end point, was 97%. The mean Harris hip score improved from 45 to 90 with pain improved in all. Subsidence 4 mm and greater occurred in only two hips, but neither has been revised. One hip was revised for mechanical loosening after a fall on the surgically treated extremity 6 years after surgery. Complications included three intraoperative fractures, one femoral fracture recognized postoperatively, one trochanteric nonunion, and one dislocation. Femoral component revision with impaction allografting and a collarless, polished, tapered stem was reproducible and improved Harris hip scores in patients with aseptic femoral component loosening and bone loss at a mean of 4.7 years after surgery.
Clinical Orthopaedics and Related Research 04/2005; · 2.53 Impact Factor
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ABSTRACT: Dislocation in primary total hip arthroplasty is common and problematic and is attributable to several factors, including previous hip surgery, neuromuscular disorders, cerebral dysfunction, psychosis, alcoholism, and female gender. Factors under the control of the surgeon include component orientation and restoration of soft-tissue tension. Prosthetic factors lowering the risk of dislocation include increasing the size of the prosthetic femoral head, keeping femoral neck circumference to a minimum, and optimizing the geometry of the acetabular component. Postoperatively, patients should be expected to comply with standard hip precautions. Treatment is with immediate closed reduction. Multiple dislocations can be treated by advancing the trochanter in the presence of inadequate soft-tissue tension, revision arthroplasty in the presence of malpositioned components, or the use of a constrained cup when intraoperative instability persists. Because the risk of redislocation is much higher than that for first-time dislocation, prevention is critical. An enhanced repair technique can be used to reconstruct the posterior soft-tissue sleeve during the posterior surgical approach. This technique has been successful in lowering the dislocation rate from 4% to 0% in a series of 395 consecutive patients.
Instructional course lectures 02/2003; 52:247-55.
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Orthopedics 02/2002; 25(1):83-5. · 2.66 Impact Factor
