Seung-Jae Lim

Early Osteolysis Following Second-Generation Metal-on-Metal Hip Replacement

BACKGROUND Total hip arthroplasty with use of metal-on-metal bearings has been reintroduced as an alternative to the use of metal-on-polyethylene bearings because of theoretical advantages such as reduced wear and a lower prevalence of osteolysis. However, we observed early osteolysis in a cohort of patients who had been managed with second-generation metal-on-metal hip replacements and investigated the possible etiologic role of metal hypersensitivity. METHODS We retrospectively analyzed 165 patients (169 hips) who had undergone primary cementless total hip replacement with a contemporary metal-on-metal total hip design between 2000 and 2002. After a minimum duration of follow-up of twenty-four months, nine patients (ten hips) had an osteolytic lesion localized to the greater trochanter. Skin-patch tests for hypersensitivity to metals were performed on the nine patients and on nine randomly selected patients with total hip replacements who did not have osteolytic changes and who were matched to the study cohort for age and gender. Microbiological cultures, histopathologic examinations, and immunohistochemical analysis were performed on samples of periprosthetic tissue that were collected during revision arthroplasty on two hips with early osteolysis. RESULTS The patients with early osteolysis had a significantly higher rate of hypersensitivity reaction to cobalt compared with controls (p = 0.031). The retrieved periprosthetic tissues showed no evidence of metallic staining, but histologic analysis revealed a perivascular accumulation of CD3-positive T-cells and CD68-positive macrophages and an absence of both particle-laden macrophages and polymorphonuclear cells. Immunohistochemical analysis demonstrated that bone-resorbing cytokines such as IL-1beta and TNF-alpha were produced mainly by infiltrating lymphocytes and activated macrophages. CONCLUSIONS These findings raise the possibility that early osteolysis in patients with this second-generation metal-on-metal hip replacement is associated with abnormalities consistent with delayed-type hypersensitivity to metal. A prospective study in which a large group of patients is evaluated with multiple diagnostic methods is needed in order to establish whether there is a causal relationship between metal hypersensitivity and osteolysis.

Ceramic failure after total hip arthroplasty with an alumina-on-alumina bearing.

BACKGROUND The mechanical properties of alumina ceramic, now in its third generation, have been markedly improved through the evolution of design features and manufacturing processes and the introduction of proof-testing. Nonetheless, because of the lack of ductility of alumina ceramic, there is concern regarding the risk of fracture during insertion or in vivo use. The purpose of the present study was to present a multicenter review of primary total hip arthroplasties performed with use of a polyethylene-ceramic composite liner combined with a ceramic femoral head, with particular attention to failure of the ceramic bearing. METHODS We evaluated 357 primary total hip arthroplasties that had been performed in 319 patients with use of a contemporary alumina-on-alumina bearing design incorporating a polyethylene-ceramic composite liner within a titanium-alloy shell coupled with a 28-mm-diameter ceramic femoral head. The procedures were performed at four participating centers from 1998 to 2001. Ceramic failure without trauma occurred in six hips (1.7%). All of these hips were revised, and the retrieved alumina implants were examined by means of visual inspection and scanning electron microscopy equipped with energy-dispersive x-ray spectrometry. RESULTS Two femoral heads fractured during the first postoperative year, and four alumina liners fractured after an average of 36.8 months in vivo. All four of the explanted alumina liners revealed evidence of rim contact with the metal neck of the femoral component. Composition analysis confirmed that surface-stain materials were titanium particles transferred from the femoral component. CONCLUSIONS Despite the theoretical improvement in the fracture toughness of a polyethylene-alumina composite liner, a relatively high rate of catastrophic ceramic bearing surface failure was still observed at the time of short-term follow-up. This finding prompted us to discontinue the use of this type of alumina bearing design.

Operative Treatment of Primary Synovial Osteochondromatosis of the Hip

BACKGROUND Primary synovial osteochondromatosis of the hip, a rare benign condition characterized by multiple intra-articular osteochondral loose bodies and synovial hyperplasia, may result in mechanical symptoms and degenerative arthritis if untreated. The purpose of this study was to report the results of arthrotomy alone or combined with anterior dislocation of the hip to perform synovectomy and removal of loose bodies in patients with this condition. METHODS We retrospectively reviewed a consecutive series of twenty-one patients (twenty-one hips) with primary synovial osteochondromatosis of the hip treated with open surgical débridement. On the basis of the extent of extra-articular involvement as seen on preoperative magnetic resonance imaging, eight of the twenty-one patients underwent synovectomy and removal of loose bodies following anterior dislocation of the hip and thirteen underwent the same procedure with arthrotomy alone. At a mean of 4.4 years postoperatively, the patients were assessed clinically and radiographically with special attention to disease recurrence, osteoarthritis progression, and surgical complications. RESULTS The mean Harris hip score for the entire series of patients improved from 58 points preoperatively to 91 points at the time of the latest follow-up. Eighteen of the twenty-one patients had a good or excellent clinical result, and seventeen patients were satisfied with the result of the surgery. The clinical scores, patient satisfaction scores, and radiographic grades of osteoarthritis at the time of the latest follow-up did not differ significantly between the group treated with dislocation and the group treated without dislocation. Symptomatic disease recurred in two of the thirteen hips treated with arthrotomy alone and in none of the hips that had undergone dislocation. However, the surgical complication rate was higher in the group treated with dislocation than it was in the group treated without dislocation (p = 0.042). While patients with some signs of mild osteoarthritis at the initial procedure had a higher rate of osteoarthritis progression, severe osteoarthritis requiring arthroplasty had developed in only one patient at the time of follow-up. CONCLUSIONS At a mean of 4.4 years postoperatively, we found that open synovectomy and removal of loose bodies for the treatment of primary synovial osteochondromatosis of the hip is a reliable procedure that can effectively relieve symptoms. Our results also indicated that synovial osteochondromatosis may recur in patients with extensive involvement who are treated with synovectomy alone without dislocation of the hip; however, surgical complications are more likely to occur in patients managed with anterior dislocation of the hip and synovectomy.

Cementless Modular Total Hip Arthroplasty in Patients Younger than Fifty with Femoral Head Osteonecrosis: Minimum Fifteen-Year Follow-Up

This study aimed to report the outcome of total hip arthroplasty (THA) with a modular femoral component in patients younger than fifty years with osteonecrosis of femoral head. Sixty-four osteonecrotic hips in fifty-five patients were available for clinical and radiographic analyses at minimum follow-up of fifteen-years. The mean Harris hip score improved from 36 points preoperatively to 92.7 points at final follow-up. Sixty-two (95.3%) hips demonstrated stable bone ingrowth. No hips showed loosening or required revision for aseptic loosening. Survivorship with an end point of stem revision for any reason was 93.8% and for aseptic loosening was 100% at 16.8years. We believe that cementless THA with a modular stem is a promising procedure for young and active patients with osteonecrosis of the femoral head.

Cobalt-alloy implant debris induce HIF-1α hypoxia associated responses: a mechanism for metal-specific orthopedic implant failure.

The historical success of orthopedic implants has been recently tempered by unexpected pathologies and early failures of some types of Cobalt-Chromium-Molybdenum alloy containing artificial hip implants. Hypoxia-associated responses to Cobalt-alloy metal debris were suspected as mediating this untoward reactivity at least in part. Hypoxia Inducible Factor-1α is a major transcription factor involved in hypoxia, and is a potent coping mechanism for cells to rapidly respond to changing metabolic demands. We measured signature hypoxia associated responses (i.e. HIF-1α, VEGF and TNF-α) to Cobalt-alloy implant debris both in vitro (using a human THP-1 macrophage cell line and primary human monocytes/macrophages) and in vivo. HIF-1α in peri-implant tissues of failed metal-on-metal implants were compared to similar tissues from people with metal-on-polymer hip arthroplasties, immunohistochemically. Increasing concentrations of cobalt ions significantly up-regulated HIF-1α with a maximal response at 0.3 mM. Cobalt-alloy particles (1 um-diameter, 10 particles/cell) induced significantly elevated HIF-1α, VEGF, TNF-α and ROS expression in human primary macrophages whereas Titanium-alloy particles did not. Elevated expression of HIF-1α was found in peri-implant tissues and synovial fluid of people with failing Metal-on-Metal hips (n = 5) compared to failed Metal-on-Polymer articulating hip arthroplasties (n = 10). This evidence suggests that Cobalt-alloy, more than other metal implant debris (e.g. Titanium alloy), can elicit hypoxia-like responses that if unchecked can lead to unusual peri-implant pathologies, such as lymphocyte infiltration, necrosis and excessive fibrous tissue growths.

Treatment of periprosthetic hip infection caused by resistant microorganisms using 2-stage reimplantation protocol.

To determine the effectiveness of staged reimplantation for the treatment of periprosthetic hip infection caused by resistant microorganisms, we performed a retrospective case-control study on 37 consecutive patients who had a culture-proven periprosthetic hip infection treated using a 2-stage reimplantation protocol. Twenty-four patients infected by resistant microorganisms were compared with 13 patients infected by nonresistant microorganisms. The second-stage reimplantation procedure was possible in 34 (92%) of the 37 patients, but the remaining 3 required permanent resection because of persistent infection. At a mean follow-up of 4.4 years, there were 4 recurrent infections and 1 aseptic cup loosening. Overall treatment failure rate was 22%. All failures occurred only in the resistant microorganism group and none in the nonresistant microorganism group (33% vs 0%; P = .032). Current 2-stage reimplantation protocol showed a high rate of treatment failure in our patients with a periprosthetic hip infection caused by resistant microorganisms.

Ten-year Results After Cementless THA With a Sandwich-type Alumina Ceramic Bearing

We analyzed the long-term results of a single-surgeon series of 102 cementless total hip arthroplasties (THAs) performed using a sandwich-type alumina ceramic bearing. The prostheses involved a porous-coated acetabular socket, a polyethylene-alumina composite liner, a 28-mm alumina head, and a grit-blasted titanium-alloy stem. Mean patient age at the time of THA was 39 years (range, 18-66 years), and 76% of the patients were younger than 50 years. All procedures were performed with use of the same surgical technique and the same implant at a single center. Mean follow-up was 115 months (range, 84-133 months). When failure was defined as revision of either the acetabular or the femoral component for any reason, Kaplan-Meier survival probability at 10 years was 95.3% (95% confidence interval, 89.5%-100%). Mean Harris Hip Score improved from 47 points (range, 16-70 points) preoperatively to 95 points (range, 85-100 points) at final follow-up. No radiographically detectable osteolysis around the acetabular or femoral component was observed in any hip. No patient reported squeaking in the operated hip. During the follow-up period, 3 hips (3%) required revision surgery; 2 underwent acetabular revision because of a ceramic liner fracture and 1 underwent revision for early loosening of the acetabular cup. Ten-year results of cementless THA with a sandwich-type alumina ceramic bearing were encouraging, and no great increase in ceramic failure rate was observed, which contrasts with the findings of previously reported short-term follow-up studies.

Variability in Femoral Component Rotation Reference Axes Measured During Navigation-Assisted Total Knee Arthroplasty Using Gap Technique

The basic objective in total knee arthroplasty is to achieve the correct amount of femoral component rotation, and this can be achieved either with a measured resection technique or indirectly with a flexion/extension gap equalization technique. We studied variability in the reference axes (posterior condylar axis, Whitesides line, transepicondylar axis) when soft tissue tension was managed intraoperatively using a navigation system. The mean angles for the transepicondylar line, Whitesides line, and the posterior condylar line from the proximal tibia resection plane were 1.29 degrees +/- 3.67 degrees (mean +/- SD; range, -7 degrees to 10.5 degrees), 3.90 degrees +/- 4.17 degrees (mean +/- SD; range, -3 degrees to 15.5 degrees), and -4.03 degrees +/- 2.71 degrees (mean +/- SD; range, -9.5 degrees to 1.0 degrees), respectively. The coefficients of variation (SD/mean x100) for these 3 variables were 283%, 106%, and 67%, respectively. Of the 3 reference axes used widely for femoral component rotation, the angles from the posterior condylar line to the proximal tibia resection plane showed the smallest range of variance.

Perioperative Risk of Hip Arthroplasty in Patients with Cirrhotic Liver Disease

We retrospectively reviewed the complete medical records of 30 patients with a diagnosis of liver cirrhosis who had undergone hip arthroplasty at three academic institutions between October 1994 and May 2001. There were 26 males and 4 females with a mean age of 60 yr at index operation. Surgical procedures included 17 primary total hip arthroplasties (THA), 8 bipolar hemiarthroplasties, and 5 revision THAs. According to the Child-Pugh scoring system, 19 cirrhotic patients were categorized as class A, 9 as class B, and 2 as class C. Eight (26.7%) of the 30 patients had one or more perioperative complications. Of these, wound infection was the most common, with a rate of 10% (3 of 30 hips). Other perioperative complications included surgical site bleeding, coagulopathy, encephalopathy, gastrointestinal bleeding, pneumonia, and arrhythmia. Death occurred in 2 (6.7%) of the 30 patients; both were Child-Pughs C cirrhotics. A higher Child-Pugh score (p=0.0001) and a high level of creatinine (p=0.0499) were associated with significantly increased perioperative complications or death. Our findings suggest that surgeons should be vigilant about perioperative complications in patients with advanced cirrhotic liver disease who undergo hip arthroplasty, albeit the mortality rates are relatively low in less severe cirrhotics.

Robot-assisted Implantation Improves the Precision of Component Position in Minimally Invasive TKA

Minimally invasive and robot-assisted procedures have potential advantages when used for total knee arthroplasty (TKA). The purpose of this cadaveric study was to examine whether robot-assisted minimally invasive procedures improve TKA alignment after modifying the robotic techniques and instruments. Total knee arthroplasties were performed on 10 pairs of fresh cadaveric femora. Ten knees were replaced using the robot-assisted minimally invasive technique and 10 using the conventional minimally invasive technique. After prosthesis implantation, limb and prosthesis alignments were investigated by measuring mechanical axis deviation, femoral and tibial sagittal and coronal inclination, and femoral rotational alignment with 3-dimensional computed tomography scans. Postoperative alignment accuracy of the implanted prostheses was better in the robot-assisted minimally invasive TKA group than in the conventional minimally invasive TKA group as judged by the rotational alignment of the femoral component (0.7°±″.3° vs 3.6°±2.2°, respectively) and the tibial component sagittal angle (7.8°±1.1° vs 5.5°±3.6°, respectively). One sagittal inclination outlier for the tibial side existed in the robotic minimally invasive TKA group, and 2 outliers for the mechanical axis, 2 for the tibial side sagittal inclination, and 2 for the femoral rotational alignment existed in the conventional minimally invasive TKA group. Higher implanted prostheses accuracy and fewer outliers in postoperative radiographic alignments can be attained with robot-assisted TKA. Minimally invasive TKA in combination with an improved robot-assisted technique is an alternative option to compensate for the shortcomings of conventional minimally invasive TKA.