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William M Mihalko

Publications and source records attributed to William M Mihalko.

17 recordsLinked to original sources
PubMed2006

Acute sciatic neuritis following total hip arthroplasty: a case report.

Nerve injuries after total hip arthroplasty are relatively uncommon, but a higher prevalence has been reported in revision arthroplasties, in women and in patients with dysplastic hips. We report a case of a patient who had a painful neuritis of the sciatic nerve after primary arthroplasty, without any objective evidence of motor or sensory deficit and had complete relief of pain after the limb lengths were matched to the contra-lateral side after revision arthroplasty.

Acute Disease↗
PubMed2006

Primary total knee arthroplasty with condylar allograft and MCL reconstruction for a comminuted medial condyle fracture in an arthritic knee--a case report.

Fractures of the distal femur in the elderly are usually due to low energy ground level fall onto a flexed knee. Pre-existing osteoarthritis and juxta-articular osteopenia in this age group result in high levels of comminution and articular damage at the time of injury, which challenges the management and treatment outcome. Preservation of knee function and early weight bearing should be the objectives of management in the geriatric population. We present in this case report of an elderly patient with comminuted medial condyle fracture with arthritic changes who had primary total knee arthroplasty utilizing condylar allograft and MCL reconstruction as an alternative to internal fixation.

Accidental Falls↗
PubMed2006

Differences between extramedullary, intramedullary, and computer-aided surgery tibial alignment techniques for total knee arthroplasty.

Traditionally, intramedullary and extramedullary tibial alignment techniques are used to obtain neutral alignment during total knee arthroplasty. Computer-assisted techniques are available to aid in obtaining alignment intraoperatively. This study analyzed the difference in tibial alignment using intramedullary and extramedullary techniques, and compared them to the resulting tibial axis as determined by a computer navigation system. The tibial alignment standard measure was determined by a spiral computed tomography (CT) study of each lower extremity. Intramedullary techniques resulted in a 1.3 degrees +/- 1.4 degrees of varus alignment and 4 degrees +/- 2.1 degrees increase in posterior slope while the extramedullary techniques resulted in 1.5 +/-1.8 degrees of valgus alignment and 1.8 degrees +/-1.1 degrees increase in posterior slope compared to the navigation system alignment. Direct measurement of metal markers on CT-scan analysis using the navigation system resulted in <0.5 degrees difference from the navigation data. Although the traditional alignment techniques are within a few degrees, the addition of the errors in all planes gives a much higher degree of error. Direct measurement of the mechanical axis using computer-guided surgical techniques for the tibia give a greater degree of accuracy compared to traditional alignment techniques.

Arthroplasty, Replacement, Knee↗
PubMed2006

Flexion and extension gap balancing in revision total knee arthroplasty.

UNLABELLED: Revision total knee arthroplasty presents a unique set of problems when attempting to balance flexion and extension gaps. Loss of soft tissue support and established deformity can make balancing difficult. One needs to balance the flexion and extension gap heights as well as medial and lateral symmetry, which may not always be attainable. We used a set of stepwise techniques to reestablish the joint line in extension using femoral augments, and then balanced the flexion gap using different sized femoral components. We retrospectively analyzed 45 patients who had revision total knee replacement with an average of 4 years followup. These patients had a mean flexion of 105 degrees and none had signs of instability in flexion or extension or on clinical exam. Despite the complex nature of revision knee arthroplasty, cases utilizing an algorithm to balance the extension and flexion gaps, with increased implant constraint when necessary, can aid in obtaining a good outcome. LEVEL OF EVIDENCE: Therapeutic study, level IV (case series). See Guidelines for Authors for a complete description of levels of evidence.

Aged↗
PubMed2006

Outcomes of total and unicompartmental knee arthroplasty for secondary and spontaneous osteonecrosis of the knee.

BACKGROUND: The reported outcomes of patients who underwent total or unicompartmental knee arthroplasty for secondary and spontaneous osteonecrosis of the knee are often from studies that lack the number of subjects necessary to generate meaningful conclusions. We systematically reviewed the available literature in order to define the outcomes of patients after total knee arthroplasty for secondary osteonecrosis and after total or unicompartmental knee arthroplasty for spontaneous osteonecrosis of the knee. METHODS: A literature review yielded twenty cohorts with demographic patient information and outcome scores (global knee scores, radiographic outcomes, and revision rates) for patients who had knee arthroplasty as treatment for either secondary or spontaneous osteonecrosis of the knee. The mean preoperative and postoperative global knee scores, the mean revision rate, and the categorization of the mean "poor" and mean "good" outcomes for the knees with each underlying disease were tabulated and reported. The demographic data and the reported mean global knee scores were weighted by the number of knees in each study. RESULTS: Total knee arthroplasty was performed in 150 knees with secondary osteonecrosis and 148 knees with spontaneous osteonecrosis, and unicompartmental knee arthroplasty was performed in sixty-four knees with spontaneous osteonecrosis. Total knee arthroplasty for spontaneous osteonecrosis of the knee was associated with the best outcomes (higher "good" and postoperative global knee scores and lower revision [3%] and "poor" outcome [6%] rates compared with the other two groups). The outcomes after total knee arthroplasty in knees with secondary osteonecrosis as well as in knees with spontaneous osteonecrosis were better in the cohorts operated on during or after 1985 than in those operated on before 1985. Similarly, the outcomes after unicompartmental knee arthroplasty in knees with spontaneous osteonecrosis of the knee were also better in the cohorts operated on during or after 1985 than in those operated on before 1985. CONCLUSIONS: Total knee arthroplasty performed as treatment for either secondary osteonecrosis or spontaneous osteonecrosis and unicompartmental knee arthroplasty performed as treatment for spontaneous osteonecrosis were associated with improved outcomes in cohorts with more recent operative dates. The evidence suggests that the use of contemporary cemented implants in total knee arthroplasty and the selective use of stems and augments in patients who have development of secondary osteonecrosis after total knee arthroplasty are producing outcomes that are comparable to those seen after total knee arthroplasty for osteoarthritis. Although the outcomes of patients who have total knee arthroplasty for the treatment of spontaneous osteonecrosis of the knee have historically been favorable, such outcomes have also shown particular improvement in the studies from more recent operative periods. Although poor outcomes were seen after unicompartmental knee arthroplasty in earlier studies of patients with spontaneous osteonecrosis of the knee, it is possible that those results were secondary to inappropriate patient selection, as the authors of the most recent and, to our knowledge, the only study to follow established operative indications regarding the use of unicompartmental knee arthroplasty reported excellent results. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions to Authors on jbjs.org for a complete description of levels of evidence.

Adult↗
PubMed2006

Effect of one- and two-pin reference anchoring systems on marker stability during total knee arthroplasty computer navigation.

OBJECTIVE: This study investigated different infrared marker reference base attachments in cadaveric bone and their effects on alignment outcome when different loads were applied. MATERIAL AND METHODS: Five cadaveric specimens were used to test four reference base attachments: a locking one-pin (4.0 mm and 5.0 mm pins) and a two-pin clamp (Hoffman fixator, 3.0 mm and 5.0 mm pins, Stryker Inc., NJ). Each was tested with metaphyseal and diaphyseal attachments. A navigation system (Stryker Navigation, MI) was used for testing with applied incremental loads and torques (65 N and 1.0 Nm) to the different reference base configurations. RESULTS: With 65 N the maximum change in distance to a verification point was 4.3 + 1.6 mm with the 4.0 mm locking pin in metaphyseal bone. No difference in verification point distances was found with any two-pin configuration. Alignment changes greater than 4 degrees resulted with the 65 N loads and a 4.0 mm pin. CONCLUSION: The results may prove beneficial in comparing the resulting error of different manufacturers and allow surgeons to realize the variability that may occur through incidental contact in the operating room.

Arthroplasty, Replacement, Knee↗
PubMed2006

Pelvic tracker effects on hip center accuracy using imageless navigation.

OBJECTIVE: Imageless computer assisted total knee surgical systems have commonly relied on determination of the functional rotational center of the femoral head as a landmark for determining the lower extremity mechanical axis. This has been accomplished through range of motion and center of rotation calculations for the femur with respect to the pelvis as the lower extremity is taken through a range of motion. Our study evaluated the use of this algorithm with and without a pelvic tracker attached to the iliac crest. MATERIALS AND METHODS: The functional center of the hip joint was also compared to the true radiographic center as determined by spiral CT data. Evaluating the different methods on six lower extremities from three whole-body cadavers revealed significant differences in the location of the calculated hip joint center, but little difference in the resulting lower extremity mechanical axis determination. The functional hip joint centers measured with and without a pelvic tracker differed from one another and from the CT-determined hip center. RESULTS: No differences were found in the coronal plane measurements, but statistically significant differences were found in the sagittal plane measurements. CONCLUSION: Algorithms that reduce the noise generated by pelvic movement should be devised to eliminate the need for a pelvic tracker.

Algorithms↗
PubMed2005

The variability of intramedullary alignment of the femoral component during total knee arthroplasty.

Intramedullary instrumentation for femoral component alignment during total knee arthroplasty is readily used. Newer alignment techniques using computer navigation are now available. This study assesses the difference in the sagittal and coronal plane alignments using a cadaveric model with 3 different entry points for intramedullary alignment compared with a navigation system. Seven cadaveric limb's results show that the anterior starting point resulted in recurvatum (-2.2 degrees +/- 1.4 degrees ), the middle starting point resulted in 1.9 degrees +/- 2.2 degrees of flexion, and the posterior starting point in 3.8 degrees +/- 2.6 degrees of flexion compared with the calculated femoral axis by the computer navigation system. When comparing the valgus angle, no statistical difference between any methods resulted (average 5.2 degrees +/- 0.9 degrees valgus). The anterior and posterior starting points were significantly different in the sagittal plane. These data suggest that alignment can be significantly affected by the starting point chosen for intramedullary instrumentation.

Arthroplasty, Replacement, Knee↗
PubMed2005

Effect of end-cutting intramedullary reamers on host-allograft contact area.

Use of large allografts in the diaphyseal region can be complicated by nonunion of the host bone to the allograft. Increasing the contact area at this interface can help prevent this from happening. This study investigated the resulting contact area with use of end-cutting reamers to prepare the interface of host and allograft bone in the daiphyseal region, as compared with hand preparation using a sagittal saw. Using a sawbone model, it was demonstrated that the end-cutting reamers produced a significantly greater contact area, compared with hand-cutting techniques.

Bone Transplantation↗
PubMed2004

Hip mechanics after posterior structure repair in total hip arthroplasty.

This study investigated the rotational response of the hip with different repairs of posterior structures after using the posterior approach in total hip replacement. Five groups were tested: (1) the normal hip without a replacement, (2) the normal hip with a vented capsule, (3) no repair of the capsule and external rotators after total hip replacement, (4) repair of only the piriformis tendon, and (5) repair of the capsule and external rotators as a flap of tissue (capsule, piriformis, obturator internus, gemellae, and quadratus) to the posterior aspect of the greater trochanter. Hemipelvis cadaveric specimens were attached to a joint testing device for testing at full extension, 30 degree, 60 degree and 90 degree hip flexion as internal and external rotation was applied to the femur and the load deflection curves were recorded. Specimens after total hip replacement were externally rotated in full extension until dislocation occurred and the maximum torque was recorded. Each specimen then was rotated internally at 90 degree flexion to the point of dislocation and the maximum torque was recorded for comparison as well. The posterior approach had significantly decreased internal rotational support with no repair or only piriformis repair. When the capsule and external rotators were repaired, a more normal load deflection curve resulted when comparing the full repair group with the normal hip. Significantly higher torque was needed to dislocate the hip in flexion when a full posterior repair was done, and most specimens dislocated in flexion without complete failure of the repair.

Arthroplasty, Replacement, Hip↗
PubMed2003

Bone resection and ligament treatment for flexion contracture in knee arthroplasty.

A retrospective study of 103 knees (88 patients) who had primary total knee arthroplasty with a flexion contracture ranging from 20 degrees to 60 degrees was done to tabulate the primary soft tissue structures released during surgery and to identify any residual deformity. The average flexion contracture preoperatively was 27.1 degrees +/- 8 degrees and postoperatively was 2.7 degrees +/- 3.4 degrees (range, 0 degrees -10 degrees ). The average followup was 70.4 months (range, 12-180 months). Only medial or lateral soft tissue balancing procedures were necessary to correct the flexion contracture in 37 knees (35.9%) and no medial or lateral release was necessary in 25 knees (24.3%), of which 16 had a balanced posterior cruciate ligament. The posterior capsule was released on the deformity side of the knee in 15 knees (14.6%) and on the opposite side of the deformity in seven knees (6.8%). The posterior cruciate ligament was balanced in 21 knees (20.4%) and was released in four knees (3.9%). For all knees in which the posterior cruciate ligament was released or balanced, it was done for excessive rollback and tightness in flexion and not for flexion contracture management. In two patients (2%) an additional 4 mm of distal femur was resected for a 45 degrees and a 25 degrees flexion contracture. The data suggest that a contracted collateral ligament is the most likely primary structure whose effective release allows correction of the flexion contracture in most cases.

Arthroplasty, Replacement, Knee↗
PubMed2003

Osteonecrosis after powered core decompression.

A 44-year-old man with alcohol-related osteonecrosis of his left femoral head, Ficat Stage 2, was treated by femoral head decompression. During this procedure the (1/4)-inch trephine driven by a power reamer became lodged in the femoral head and became hot to the touch. The trephine eventually was removed with difficulty after the decompression was completed. Four and a half years later, the patient continued to have progressive pain and difficulty ambulating. A radiograph at the time revealed a wide zone of symmetric increased density about the core decompression track. A total hip arthroplasty was done, yielding the femoral head and neck for study. Histologic sections of the femoral head and neck showed that the entire length of the core decompression track in the specimen was surrounded by 2.7 cm of unrepaired necrotic bone. The evidence suggests that extensive additional necrosis was produced iatrogenically during the core decompression with the powered trephine. Necrosis secondary to either heat generation or increased pressure along the trephine track is presented as possible mechanisms for this unusual finding.

Adult↗
PubMed2002

Ranawat Award paper. Effect of selective lateral ligament release on stability in knee arthroplasty.

The current authors evaluated a fundamental approach to balancing the lateral ligaments of the knee that begins with aligning the implants correctly in flexion and extension, proceeds to assessing stability in flexion and extension, and concludes with releasing tight structures based on their function throughout the arc of flexion. Seventeen knees from cadavers were used to evaluate stability at various degrees of flexion after total knee arthroplasty, and then stability was reevaluated after release of selected ligaments. The iliotibial band and posterior capsule were effective lateral stabilizers only in full extension. The lateral collateral ligament had a major stabilizing effect throughout the arc from 0 degrees to 90 degrees flexion. The iliotibial band and popliteus tendon and posterolateral corner capsule had little effect when the other ligaments were intact. When tested in the absence of the other lateral ligaments, the popliteus tendon and posterolateral corner capsule had significant stabilizing effects throughout the flexion arc. The popliteus tendon exerted its effect mostly from 60 degrees to 90 degrees flexion. The posterolateral corner capsule was effective mostly at 0 degrees to 30 degrees flexion. The iliotibial band had a significant stabilizing effect from 0 degrees to 30 degrees flexion.

Arthroplasty, Replacement, Knee↗
PubMed2002

Surgical procedure for flexion contracture and recurvatum in total knee arthroplasty.

A specific protocol for dealing with flexion contracture and recurvatum in total knee arthroplasty surgery was evaluated. In cases of flexion contracture, this protocol included choosing the larger femoral size when the femur was between sizes to make the flexion space smaller and to allow overresection of the tibial surface to correct the flexion contracture. In all cases, bone resection was done first, osteophytes were resected next, and ligaments were balanced after the trials were in place. Extra bone was resected from the distal femur to correct residual flexion contracture only if ligament balancing failed to correct the deformity. In cases of recurvatum, the smaller femoral size was chosen to enlarge the flexion space, allowing underresection of the tibia to stabilize the knee in extension. The cutting guides were positioned so that 3 to 5 mm less than the distal thickness of the femoral component was removed to stabilize the knee in extension. To evaluate this protocol, a computerized database was used to review records of 530 patients (552 knees) who had flexion contracture (542 knees) or recurvatum (10 knees) before surgery. Ligament release and correction of varus or valgus contracture corrected flexion contracture to less than 3 degrees in 515 knees (95%). Sixteen knees (3%) had release of the posterior capsule to correct residual flexion contracture, and 11 knees (2%) required overresection of the distal femoral surface to achieve correction of flexion contracture. By 1 year the flexion contracture was 2 degrees +/- 1 degree. In the knees with preoperative recurvatum, none had residual recurvatum at the conclusion of surgery, and none had recurrent deformity. None of the knees required a hinge or a stabilized component with a highly conforming central post.

Aged↗
PubMedDate not supplied

Proximal femoral physis shear in slipped capital femoral epiphysis--a finite element study.

The following finite element study was conducted to determine whether increased body weight, femoral retroversion, and varus hip loading could sufficiently raise physeal shear strains and stresses above the yield point and predispose an adolescent hip to a slip. A computer tomography scan of a 13-year-old child with slipped capital femoral epiphysis was used to generate a solid model of the proximal femur and physis. The model was parameterized using 3-dimensional software to generate three difference angles of femoral neck version-neutral, 15 degrees retroversion, and 15 degrees anteversion. Loads of 2.7 times body weight in a 46- and 86-kg child were applied to the proximal femur to model stance on one leg. In addition, the loading vector was reoriented at various degrees of varus to study the effect of varus loading on physis shear. The results demonstrated that physis stress, strain, and displacement increased with greater body weight, retroversion, and varus displacement of the loading vector. Physis shear strain in hips with a combination of varus loading and femoral neck retroversion exceeded the reported ultimate strain values for cartilaginous soft tissues. The finite element models suggest that in an overweight child, the combination of retroversion and varus hip load may be sufficient to increase physeal strains above the yield point and result in a slip.

Adolescent↗
PubMedDate not supplied

Total knee arthroplasty in the valgus knee.

The valgus knee presents a unique set of problems that must be addressed during total knee arthroplasty. Both bone and soft-tissue deformities complicate restoration of proper alignment, positioning of components, and attainment of joint stability. The variables that may need to be addressed include lateral femoral condyle or tibial plateau deficiencies secondary to developmental abnormalities, and/or wear; primary or acquired contracture of the lateral capsular and ligamentous structures; and, occasionally, laxity of the medial collateral ligament. Understanding the specific pathologic anatomy associated with the valgus knee is a prerequisite to selecting the proper surgical method to optimize component position and restore soft-tissue balance.

Arthroplasty, Replacement, Knee↗