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J H Lonner

Publications and source records attributed to J H Lonner.

At least 19 recordsLinked to original sources
PubMed2006

T1rho relaxation mapping in human osteoarthritis (OA) cartilage: comparison of T1rho with T2.

PURPOSE: To quantify the spin-lattice relaxation time in the rotating frame (T1rho) in various clinical grades of human osteoarthritis (OA) cartilage specimens obtained from total knee replacement surgery, and to correlate the T1rho with OA disease progression and compare it with the transverse relaxation time (T2). MATERIALS AND METHODS: Human cartilage specimens were obtained from consenting patients (N = 8) who underwent total replacement of the knee joint at the Pennsylvania Hospital, Philadelphia, PA, USA. T2- and T1rho-weighted images were obtained on a 4.0 Tesla whole-body GE Signa scanner (GEMS, Milwaukee, WI, USA). A 7-cm diameter transmit/receive quadrature birdcage coil tuned to 170 MHz was employed. RESULTS: All of the surgical knee replacement OA cartilage specimens showed elevated relaxation times (T2 and T1rho) compared to healthy cartilage tissue. In various grades of OA specimens, the T1rho relaxation times varied from 62 +/- 5 msec to 100 +/- 8 msec (mean +/- SEM) depending on the degree of cartilage degeneration. However, T2 relaxation times varied only from 32 +/- 2 msec to 45 +/- 4 msec (mean +/- SEM) on the same cartilage specimens. The increase in T2 and T1rho in various clinical grades of OA specimens were approximately 5-50% and 30-120%, respectively, compared to healthy specimens. The degenerative status of the cartilage specimens was also confirmed by histological evaluation. CONCLUSION: Preliminary results from a limited number of knee specimens (N = 8) suggest that T1rho relaxation mapping is a sensitive noninvasive marker for quantitatively predicting and monitoring the status of macromolecules in early OA. Furthermore, T1rho has a higher dynamic range (>100%) for detecting early pathology compared to T2. This higher dynamic range can be exploited to measure even small macromolecular changes with greater accuracy compared to T2. Because of these advantages, T1rho relaxation mapping may be useful for evaluating early OA therapy.

Arthroplasty, Replacement, Knee↗
PubMed2001

Changes in bone density after cemented total knee arthroplasty: influence of stem design.

Total knee arthroplasty has shown excellent survivorship in short-term and intermediate-term studies. With longer follow-up, however, aseptic loosening becomes an increasing cause of failure. Dual-energy x-ray absorptiometry scanning has shown that stress shielding occurs from altered mechanical loading. The purpose of this study is to determine if tibial stem design affects bone density in the longterm. Bone densities in the proximal tibia with and without cemented stems were compared at an average of 94 months after surgery. The bone quality under the Miller-Galante I prosthesis, which has 4 0.5-cm pegs, was compared with the bone quality under a Press-Fit Condylar prosthesis with a single 4-cm stem. Each group was also compared with the unoperated contralateral tibia. Results showed that there is a significantly reduced density of bone in the tibial metaphysis in the cemented stemmed group but not in the pegged group. There were no changes distally in the diaphyseal bone. This study supports the contention that the use of a cemented stem reduces proximal stresses and may result in proximal bone resorption. Although the use of a stem provides excellent resistance to lift-off and shear, it comes at a price. The proximal resorption may contribute to the persistence of tibial component loosening as a primary threat to survivorship. This bone loss may complicate revision surgery. Consideration should be given to using shorter tibial stems, less cement, or alternative designs that avoid long-stem fixation.

Absorptiometry, Photon↗
PubMed2001

A meta-analysis of thromboembolic prophylaxis in total knee arthroplasty.

Deep venous thrombosis (DVT) is common in total knee arthroplasty (TKA). Because of the rarity of the most serious outcomes, most randomized controlled trials lack the power to analyze these outcomes. A meta-analysis was performed for agents used in DVT prophylaxis in TKA employing a Medline literature search. Study inclusion criteria were randomized controlled trials comparing prophylactic agents in elective TKA with mandatory screening for DVT by venography. Fourteen studies (3,482 patients) met inclusion criteria. For total DVT, all agents except dextran and aspirin protected significantly better than placebo (P < .0001). For proximal DVT rates, low-molecular-weight heparin was significantly better than warfarin (P = .0002). There was a trend that aspirin was better than warfarin (P = .0106). No significant difference was found for symptomatic pulmonary embolism, fatal pulmonary embolism, major hemorrhage, or total mortality.

Aged↗
PubMed2001

The Internet as a communication tool for academic orthopaedic surgery departments in the United States.

BACKGROUND: The Internet's appeal as an affordable, accessible medium for information transfer makes it a potentially useful tool for practicing physicians. In the past several years, Internet-based health-care companies have proliferated, and many medical centers have established individual web sites. The purpose of the present study was to evaluate academic orthopaedic surgery departments in the United States with respect to Internet visibility and content. METHODS: We reviewed existing web sites for the 154 departments or divisions of orthopaedic surgery currently accredited for resident education by the Accreditation Council for Graduate Medical Education. The study sample consisted of the 113 departments that had a web page listed in the FREIDA (Fellowship and Residency Electronic Interactive Database) database. Each web site was assessed with regard to its informational value in the categories of clinical services, resident education, and physician recruitment. In addition, three commonly employed browsing engines were used to search for individual web sites and to determine their ease of accessibility. RESULTS: In the category of clinical services, sixty-five (57.5%) of the 113 sites provided faculty listings and forty-nine (43.4%) provided office telephone numbers and locations. Only thirteen sites provided information on common orthopaedic conditions, and five had links to other patient-education sites. In the category of resident education, twenty-four sites (21.2%) had online academic schedules, but only two provided access to complete conferences or teaching files. In the category of physician recruitment, ninety-one provided a description of their residency program and fifty-four had information on the application process, but only twenty-six web pages offered detailed departmental statistics. In terms of accessibility, fifty-three programs (46.9%) were identified by one of three popular search engines, seventeen (15%) were identified by more than one search engine, and two (1.8%) were identified by all three. CONCLUSIONS: Academic orthopaedic surgery departments in the United States underutilize the Internet as a source of clinical and educational services. In addition, existing orthopaedic web sites are difficult to access with use of popular search engines. Thus, academic orthopaedic surgery departments in the United States are missing a valuable opportunity to promote awareness of their institutions and to become educational resources for the community.

Academic Medical Centers↗
PubMed2001

Role of knee aspiration after resection of the infected total knee arthroplasty.

Recognizing persistent infection after resection arthroplasty and implantation of cement spacers in the infected total knee arthroplasty is often difficult. The purpose of this study was to determine whether aspiration of the knee after resection arthroplasty is valuable for determining the presence of ongoing infection. Thirty-four previously infected knees that were aspirated and cultured after resection arthroplasty, implantation of cement spacers, and intravenous antibiotics for an average of 6.3 weeks were identified. There were 8 cases of persistent infection-none identified on preoperative aspiration. Two preoperative cultures were false positive for Staphylococcus epidermidis. Preoperative cultures were negative in 32 knees, with 8 false-negative results. The antibiotic-free interval among all cases averaged 20 days; the cases with false-negative results from aspiration had an antibiotic-free interval averaging 11.5 days, compared with an average of 26 days among all other cases. Aspiration of knees after resection arthroplasty had sensitivity of 0%, positive predictive value of 0%, and accuracy of 71%. Specificity was 92%, and negative predictive value was 75%. A negative result from joint aspiration after resection arthroplasty does not necessarily rule out the presence of ongoing infection. False-negative results may be observed if joint aspiration is not delayed more than 2 to 3 weeks.

Aged↗
PubMed2001

Tibial osteonecrosis.

Spontaneous osteonecrosis of the tibial plateau involves a continuum of change observed in the subchondral zone that is commonly associated with early and mid stages of osteoarthritis. The typical patient is an elderly woman who experiences a sudden onset of pain in the medial aspect of the knee. The diagnosis of this under-appreciated clinical entity may be difficult, but careful examination and judicious use of imaging studies, as well as a high index of suspicion, may facilitate the accurate diagnosis. Although the radiographs may initially be normal (with the exception of mild arthrosis), radionuclide scans and MRI can be of great value. The MRI studies usually show a decreased signal intensity on a T1-weighted image, but may be normal in the early course of the disease. The T2-weighted images and fat suppression views are helpful in establishing a diagnosis and determining the extent of involvement. Recognition of this problem may help to avoid unnecessary intra-articular surgery. Many of these patients have complete or partial resolution of symptoms by 1 year, after a period of protected weight bearing. Nonetheless, surgery may be necessary for more advanced lesions and in those patients with progressive arthrosis.

Adult↗
PubMed2001

Lateral patellar chamfer in total knee arthroplasty.

Derangement of the anterior compartment of the knee can cause patellofemoral dysfunction in up to 50% of secondary surgeries after total knee arthroplasty. A technique of patellar chamfering is described that can minimize the risk of anterior knee pain from lateral patellar impingement without compromising bone stock for future operations.

Arthroplasty, Replacement, Knee↗
PubMed2000

The predictive value of indium-111 leukocyte scans in the diagnosis of infected total hip, knee, or resection arthroplasties.

To evaluate the usefulness of the indium-111 scan in detecting actually or potentially infected total hip, knee, and resection arthroplasties, 153 scans were performed on 143 patients who underwent reoperation for a loose or painful total joint arthroplasty or a resection arthroplasty between 1990 and 1996. Scans were interpreted as infected, not infected, or equivocal by an experienced nuclear medicine radiologist. Patients were considered to be infected if they met any 2 of the following criteria: i) positive intraoperative cultures, ii) final permanent histologic section indicating acute inflammation, and iii) intraoperative findings of gross purulence within the joint. Twenty-six patients (17%) met the infection criteria at the time of reoperation. Indium scans were found to have a 77% sensitivity, 86% specificity, 54% and 95% positive and negative predictive values, and 84% accuracy for the prediction of infection. Of 6 equivocal scans, none were infected. The results of this study suggest limited indications for the use of the indium-111 scan in the evaluation of painful hip, knee, or resection arthroplasties. A negative indium scan may be helpful in suggesting the absence of infection in cases in which the diagnosis is not otherwise evident.

Adult↗
PubMed2000

Total knee arthroplasty in patients 40 years of age and younger with osteoarthritis.

The results of 32 total knee arthroplasties performed for osteoarthritis in 32 patients who were 40 years of age or younger are reviewed. At a mean followup of 7.9 years (minimum, 5 years), the Knee Society knee scores increased from an average of 47 to 88 points, and the function scores increased from 45 to 70 points. Overall, Knee Society knee scores were considered good or excellent in 82% of patients (26 knees) and fair or poor in 18% (six knees). Postoperative function scores were good or excellent in only 40% (13 knees). The average postoperative flexion arc was 110 degrees. If patients involved in worker's compensation cases are excluded from analysis, the results improved substantially, with range of motion averaging 113 degrees, and Knee Society knee scores and function scores averaging 92 points and 77 points, respectively. Excluding the five patients involved in workmen's compensation cases, knee scores were good or excellent in 91% of patients (25 knees) and function scores were good or excellent in 50% of patients (14 knees). Three revisions were performed for aseptic failure; one additional patient has radiographic evidence of tibial loosening, representing an aseptic failure rate of 12.5% at 8 years. Although slightly higher than observed in older patients, this failure rate still may be considered acceptable for this population of patients with severely affected knees who are not considered candidates for nonarthroplasty surgery. Despite a slightly higher tendency for aseptic failures in this group of patients, cemented total knee arthroplasty may provide some patients younger than 40 years of age with severe debilitating and recalcitrant osteoarthrosis, an important option with reasonable mid- and long-term results.

Adult↗
PubMed2000

Simultaneous femoral osteotomy and total knee arthroplasty for treatment of osteoarthritis associated with severe extra-articular deformity.

BACKGROUND: In the presence of large extra-articular deformity, complex imbalance of the collateral ligaments may result if standard techniques of soft-tissue releases and intra-articular bone resection are used during total knee arthroplasty. The purpose of this paper is to review our experience with simultaneous corrective osteotomy and total knee arthroplasty for the treatment of severe extra-articular femoral deformity associated with ipsilateral osteoarthritis of the knee. METHODS: The results of simultaneous corrective osteotomy and total knee arthroplasty in eleven knees with osteoarthritis and associated extra-articular angular deformity of the femur were reviewed retrospectively. The femoral deformity resulted from fracture malunion in ten knees and from hypophosphatemic rickets in one. There were five primarily uniplanar deformities (four varus deformities and one antecurvatum deformity), five biplanar (varus and antecurvatum) deformities, and one triplanar (varus, antecurvatum, and internal rotation) deformity. Four knees were approached through a standard medial parapatellar arthrotomy and seven, through an anterolateral subvastus approach with an osteotomy of the tibial tubercle. The site of the femoral osteotomy was fixed with a blade-plate in seven patients, a press-fit long-stemmed femoral component in two, and a retrograde femoral nail in two. An extramedullary alignment system was utilized in eight patients, and intramedullary alignment was used in three. RESULTS: The duration of follow-up averaged forty-six months (range, twenty-six to eighty-eight months). According to the classification system of the Knee Society, the mean function score increased from 22 points preoperatively to 81 points at the time of follow-up and the mean knee score increased from 10 points preoperatively to 87 points at the time of follow-up. The mean flexion contracture decreased from 19 degrees preoperatively to 2 degrees at the time of follow-up. The arc of motion averaged 56 degrees (range, 30 to 75 degrees) preoperatively and 89 degrees (range, 65 to 115 degrees) at the time of follow-up. The mechanical alignment in the coronal plane was restored to within 2 degrees of normal in each patient. Ten femoral osteotomy sites healed, and one, in a patient treated with a press-fit long-stemmed femoral component, had not healed by the time of follow-up. All seven sites of the tibial tubercle osteotomies healed. There were no complete radiolucent lines at the prosthetic interfaces, and no total knee arthroplasty was revised. One patient had a nonfatal postoperative pulmonary embolism. As determined by clinical examination and the patients' assessment of function, no ligament imbalance was noted at the time of the most recent follow-up. CONCLUSIONS: Simultaneous femoral osteotomy and total knee arthroplasty is a technically difficult but effective treatment for patients with severe femoral deformity associated with ipsilateral osteoarthritis of the knee. We recommend that the femoral osteotomy site be secured with a plate or a locked intramedullary nail, depending on the location of the deformity and the subsequent osteotomy.

Adult↗
PubMed2000

A meta-analysis of thromboembolic prophylaxis following elective total hip arthroplasty.

BACKGROUND: Although several agents have been shown to reduce the risk of thromboembolic disease, there is no clear preference for thromboembolic prophylaxis in elective total hip arthroplasty. The purpose of this study was to define the efficacy and safety of the agents that are currently used for prophylaxis against deep venous thrombosis -- namely, low-molecular-weight heparin, warfarin, aspirin, low-dose heparin, and pneumatic compression. METHODS: A Medline search identified all randomized, controlled trials, published from January 1966 to May 1998, that compared the use of one of the prophylactic agents with the use of any other agent or a placebo in patients undergoing elective total hip arthroplasty. For a study to be included in our analysis, bilateral venography had to have been performed to confirm the presence or absence of deep venous thrombosis. Fifty-two studies, in which 10,929 patients had been enrolled, met the inclusion criteria and were included in the analysis. The rates of distal, proximal, and total (distal and proximal) deep venous thrombosis; symptomatic and fatal pulmonary embolism; minor and major wound-bleeding complications; major non-wound bleeding complications; and total mortality were determined for each agent in each study. The absolute risk of each outcome was determined by dividing the number of events by the number of patients at risk. A general linear model with random effects was used to calculate the 95 percent confidence interval of risk. A crosstabs of study by outcome was performed to test homogeneity (ability to combine studies). The risk of each outcome was compared among agents and between each agent and the placebo. RESULTS: With prophylaxis, the risk of total (proximal and distal) deep venous thrombosis ranged from 17.7 percent (low-molecular-weight heparin) to 31.1 percent (low-dose heparin); the risk with prophylaxis with any agent was significantly lower than the risk with the placebo (48.5 percent) (p < 0.0001). The risk of proximal deep venous thrombosis was lowest with warfarin (6.3 percent) and low-molecular-weight heparin (7.7 percent), and again the risk with any prophylactic agent was significantly lower than the risk with the placebo (25.8 percent) (p < 0.0001). Compared with the risk with the placebo (1.51 percent), only warfarin (0.16 percent), pneumatic compression (0.26 percent), and low-molecular-weight heparin (0.36 percent) were associated with a significantly lower risk of symptomatic pulmonary embolism. There were no significant differences among agents with regard to the risk of fatal pulmonary embolism or of mortality with any cause. The risk of minor wound-bleeding was significantly higher with low-molecular-weight heparin (8.9 percent) and low-dose heparin (7.6 percent) than it was with the placebo (2.2 percent) (p < 0.05). Compared with the risk with the placebo (0.28 percent), only low-dose heparin was associated with a significantly higher risk of major wound-bleeding (2.56 percent) and total major bleeding (3.46 percent) (p < 0.0001). CONCLUSIONS: The best prophylactic agent in terms of both efficacy and safety was warfarin, followed by pneumatic compression, and the least effective and safe was low-dose heparin. Warfarin provided the lowest risk of both proximal deep venous thrombosis and symptomatic pulmonary embolism. However, there were no identifiable significant differences in the rates of fatal pulmonary embolism or death among the agents. Significant risks of minor and major bleeding complications were observed with greater frequency with certain prophylactic agents, particularly low-molecular-weight heparin (minor bleeding) and low-dose heparin (both major and minor bleeding).

Aged↗
PubMed1999

Total knee arthroplasty in patients 90 years of age and older.

With increasing longevity, more patients older than age 90 now are becoming candidates for total knee arthroplasty. This article reviews our experience with the perioperative morbidity and early outcomes in 12 patients older than age 90, undergoing 15 total knee surgeries. Postoperative Knee Society clinical and functional scores showed excellent outcomes, and the quality of life is enhanced. There were no significant surgical complications; however, there were several nonsurgical complications, including mental confusion (3), urinary retention (3), atrial fibrillation (2), atrial flutter (1), and gallstone retention and gastrointestinal bleed (1). Most of these complications stemmed directly from the preoperative medical condition. These are predictive and therefore may be recognized early and treated aggressively. Total knee surgery can be performed safely in patients older than 90 years old with excellent pain relief and enhanced quality of life. The surgeon should be aware of the patient's past medical history because this predisposes to postoperative morbidity.

Aged↗
PubMed1999

Total knee arthroplasty for post-traumatic arthrosis.

The outcomes of total knee arthroplasty for post-traumatic arthrosis were studied in 31 knees. The average age at arthroplasty was 60 years old (range, 36-78 years). The interval from fracture to total knee arthroplasty averaged 13 years. Simultaneous corrective osteotomy was necessary in 4 patients to correct axial alignment and preserve ligamentous integrity. Follow-up averaged 46 months. Mean arc of motion increased significantly, from 94 degrees to 100 degrees (P = .027). Average function score improved from 44 to 72 points. This change was statistically significant (P<.0001). Knee Society knee scores also improved significantly, from 36 to 78 points (P<.0001). At most recent follow-up, the functional scores were considered excellent or good in 58%; knee scores were considered excellent or good in 71% of cases. All periarticular osteotomies and tibial tubercle osteotomies healed uneventfully within 16 weeks. Complications occurred in 57% of cases, including aseptic failure (26%), septic failure (10%), patellar tendon rupture (3%), patellar subluxation (6%), thromboembolism (6%), and wound breakdown requiring debridement and muscle flap coverage (6%). Despite significant improvements in motion and function, patients with post-traumatic arthrosis are susceptible to high rates of complications. Adverse outcomes can be minimized by restoring limb alignment, soft tissue balance, and component alignment and by preserving vascularity of the skin and subcutaneous tissues.

Adult↗
PubMed1999

Prodromes of failure in total knee arthroplasty.

A total of 102 revision total knee arthroplasties (TKAs) were reviewed to determine the prodromal symptoms and radiographic findings associated with failure. Presenting symptoms included pain (84%); swelling (76%); progressive varus or valgus deformity (19%); instability (17%); stiffness (17%); clicking or grinding (7%); catching (4%); and patellar pain, subluxation, or clicking (4%). Radiographs were diagnostic in 91% of cases, demonstrating complete radiolucencies (80%), polyethylene wear (43%), component breakage (5%), metallic debris (3%), patellar subluxation or dislocation (4%), and osteolysis (4%). Gross intraoperative findings included polyethylene wear (72%), osteolysis (22%), metal-wear synovitis (9%), component breakage (6%), patellar wear and dissociation (4%), and occult sepsis (5%). The average duration of symptoms was 13 months; the interval between orthopedic evaluations averaged 23 months. Based on this information, we recommend that an annual questionnaire and weight-bearing radiographs be used to ensure adequate surveillance of TKA patients and avoid complications associated with delay in diagnosis of polyethylene wear or implant loosening.

Aged↗
PubMed1999

The surgeon as a hand patient: the clinical and psychological impact of hand and wrist fractures.

To gain insight into the management of patients with hand and wrist injuries, a series of clinical and psychological analyses was performed on 9 surgeons, each of whom underwent operative fixation of a hand or wrist fracture. The results of these analyses suggest that the functional outcome after hand surgery was affected by the surgeons' personality, motivation, and ability to accept and adapt to the injury; the nature of the injury; and the importance of the hand to the surgeons' careers. Surgeons are highly motivated and compulsive individuals who consider their career involvement a major source of identity and self-worth. Most returned to their operative duties ahead of the schedule set by their hand surgeons (average, 25 days after surgery), regarded their injuries as a positive challenge, and changed their lifestyles after injury to protect their hands.

Adult↗
PubMed1999

Analysis of frozen sections of intraoperative specimens obtained at the time of reoperation after hip or knee resection arthroplasty for the treatment of infection.

BACKGROUND: Despite the effectiveness of a two-stage exchange protocol for the treatment of deep periprosthetic infection, infection can persist after resection arthroplasty and treatment with antibiotics, leading to a failed second-stage reconstruction. Intraoperative analysis of frozen sections has been shown to have a high sensitivity and specificity for the identification of infection at the time of revision arthroplasty; however, the usefulness of this test at the time of reoperation after resection arthroplasty and treatment with antibiotics is, to our knowledge, unknown. METHODS: The medical records of sixty-four consecutive patients who had had a resection arthroplasty of either the knee (thirty-three patients) or the hip (thirty-one patients) and had had intraoperative analysis of frozen sections of periprosthetic tissue obtained at the time of a second-stage operation were reviewed. The mean interval between the resection arthroplasty and the attempted reimplantation was nineteen weeks. The results of the intraoperative analysis of the frozen sections were compared with those of analysis of permanent histological sections of the same tissues and with those of intraoperative cultures of specimens obtained from within the joint. The findings of the analyses of the frozen sections and the permanent histological sections were considered to be consistent with acute inflammation and infection if a mean of ten polymorphonuclear leukocytes or more per high-power field (forty times magnification) were seen in the five most cellular areas. RESULTS: The intraoperative frozen sections of the specimens from two patients (one of whom was considered to have a persistent infection) met the criteria for acute inflammation. Four patients were considered to have a persistent infection on the basis of positive intraoperative cultures or permanent histological sections. Overall, intraoperative analysis of frozen sections at the time of reimplantation after resection arthroplasty had a sensitivity of 25 percent (detection of one of four persistent infections), a specificity of 98 percent, a positive predictive value of 50 percent (one of two), a negative predictive value of 95 percent, and an accuracy of 94 percent. CONCLUSIONS: A negative finding on intraoperative analysis of frozen sections has a high predictive value with regard to ruling out the presence of infection; however, the sensitivity of the test for the detection of persistent infection is poor.

Arthroplasty, Replacement, Hip↗