Purpose

Two-stage re-implantation after infection of Total Knee Arthroplasty (TKA), remains the gold standard to which other forms of treatment should be compared. The primary purpose of this study was to determine the rates of failure and functional outcome of two stage revision TKA for treatment of infection comparing cemented posterior stabilized compared to constrained condylar implants.

Purpose

Infection following total knee arthroplasty is a devastating complication, requiring considerable effort on the part of the surgeon to eradicate the infection and restore joint function. Two-stage revision is the standard of care in the treatment of peri-prosthetic infection, using a temporary antibiotic-impregnated spacer between procedures. However, controversy remains concerning the use of static versus dynamic spacers, as well as the spacer material. The purpose of this study was to evaluate the clinical outcomes and complications of two-stage revision total knee arthroplasty in patients treated with a metal-on-polyethylene articulating spacer, as compared to those treated with a static antibiotic-impregnated cement spacer at the same centre.

Purpose

The literature indicates that the tibial component in total knee arthroplasty (TKA) should be placed in internal rotation not exceeding 18 to the line connecting the geometrical center of the proximal tibia and the middle of the tibial tuberosity. These landmarks may not be easily identifiable intraoperatively. Moreover, an angle of 18 is difficult to measure with the naked eye.

Purpose: Component malrotation is a recognized cause of post total knee arthroplasty (TKA) pain. The objective of this study was to evaluate the functional outcomes of TKA revision for component malrotation, and to compare it to revision surgeries for aseptic loosening as a control comparison group.

Method: Twenty four patients who had TKA revision due to component malrotation as the only objective abnormality were reviewed. Only patients with preoperative computerized tomography (CT) documentation of 3° or more malrotation of at least one of the components were included. Mean combined rotation was 6.8° (range, − 12 − 3) excessive internal rotation. Twenty four matched control patients had TKA revision due to aseptic loosening.

Results: Mean follow up was 37 months (range, 24–65). Mean interval from index surgery was 41 months (range, 24–65) for the study group and 98 months (range, 11–222) for the control group (p=0.0003). Preoperative Knee Society Score (KSS) improved by 49 points (range, 16–80) at 6 months postoperatively for the malrotation patients and by 39 (range, − 7–78) for the loosening patients (p=0.08). At last follow-up, KSS was 80 (range, 60–89) for the malrotation group and 75 (range, 26–90) for the loosening group (p=0.14).

Conclusion: We recommend the use of CT scans in evaluation of all patients with early painful TKA’s and no objective evidence of infection. When component malrotation is demonstrated, we believe the results of this study validate consideration of early revision.

Purpose: The literature regarding the outcome of total knee arthroplasty following distal femoral varus osteotomy is limited. The largest published series to date of eleven such patients suggested that medio-lateral constrained implants are commonly required as ligament balancing is difficult. This study presents mid-term outcomes of patients treated with total knee arthroplasty following distal femoral varus osteotomy at a single center.

Method: Twenty-two consecutive distal femoral varus osteotomies (21 patients) converted to total knee arthroplasties were reviewed at a mean follow-up of five years (range, two to 14 years). The mean duration between osteotomy and conversion to arthroplasty was 12 years (range, three to 21 years). In 14 patients (15 knees) the underlying etiology for the femoral osteotomy was primary knee osteoarthritis with valgus deformity, while in seven patients the procedure was performed to unload a fresh osteochondral allograft of either the lateral tibia (five patients) or femur (two patients). It is the authors’ routine to use posterior stabilized implants were used in all total knee arthroplasty surgeries. Femoral stems were used in six knees in which the bone quality was clinically determined by the surgeon to be sufficiently deficient to predispose to periprosthetic fractures, while the remaining sixteen knees were treated with unstemmed components. Modified knee society scores were used to evaluate the clinical outcomes preoperatively and at most recent follow-up.

Results: The mean knee society knee and function scores in surviving knees improved from 50 points (range, 10 to 75 points) and 50 points (range, 30 to 70 points) pre-operatively, to 91 points (range, 67 to 100 points) and 64 points (range, 50 to 70 points) at final follow-up, respectively. The mean arc of motion improved from 94 degrees (range, 70 to 115 degrees) to 114 degrees (range, 90 to 130 degrees). Two patients underwent revision arthroplasty for polyethylene wear and component loosening at eight and 11 years following the index arthroplasty, respectively. There were no fractures, infections or wound complications.

Conclusion: Total knee arthroplasty following distal femoral varus osteotomy reliably decreases pain and improves knee function. Standard posterior stabilized components provide satisfactory stability after appropriate ligamentous balancing, without the need for stemmed or highly constrained components in the majority of patients.

Purpose: Single anesthetic bilateral total knee arthroplasty (SABTKA) is a controversial procedure with a questionable safety profile. The purpose of this study was to determine if specific, individual preoperative medical co-morbidities can predict perioperative complications in patients undergoing SABTKA.

Method: The records of all SABTKA performed between 1997 and 2007 at 1 large community hospital and 1 academic, university hospital were retrospectively reviewed. Complete demographic data, preoperative co-morbidities (cardiovascular disease, COPD, diabetes, and hypertension), and perioperative complications for 156 patients were collected and analyzed using logistic multivariate regression analysis. Comparison was made to an age, gender, and co-morbidity matched cohort of patients treated with unilateral TKA.

Results: In the SABTKA group only 11% of patients had a preoperative history of cardiovascular disease yet 89% of all post operative myocardial infarctions (MI) occurred in this population (p< 0.001, Odds Ratio 57.8). Cardiovascular disease also predicted need for admission to ICU (p< 0.001, Odds Ratio 50.8), and number of days spent in the ICU (p< 0.001). In those patients without preoperative cardiovascular disease or COPD the rate of MI was only 0.64%. All differences were significant when compared to the matched unilateral TKA cohort. Age, gender, diabetes, and hypertension did not predict perioperative complications in the SABTKA cohort.

Conclusion: The literature indicates there are certain populations of patients at higher risk for perioperative complications after SABTKA. This study clearly identifies a subpopulation of patients that have cardiovascular disease and are at an unacceptably high risk of perioperative MI. Cardiovascular disease should likely be considered an absolute contraindication to SABTKA.

Purpose: Acetabular component revision in the context of large, contained bone defects with less than 50% host-bone-contact traditionally required roof reinforcement or antiprotrusio cages. Trabecular Metal (TM) cups (Zimmer, Warsaw, Indiana) may offer a viable treatment alternative. The objective of this study was to evaluate the clinical and radiological outcome of this mode of treatment.

Method: Fifty-four hip revision acetabular arthroplasty procedures performed with TM cups for contained defects offering ≤50% contact with native bone were prospectively followed. Average follow-up was 45 months (range 24–71). All patients were clinically and radiographically evaluated for evidence of loosening or failure.

Results: Contact with bleeding host bone ranged from 0 to 50% (average 23%). At latest follow up 43 (79.6%) arthroplasties had excellent or good results, 8 (14.8%) cases had medium or fair results and 3 cases (5.6%) had poor results. Two cups failed and had to be revised. Two additional cups had radiological evidence of probable loosening. Overall preliminary survivorship of the revision acetabulae was 96%. Complications included 4 dislocations and 1 sciatic nerve palsy.

Conclusion: Treatment of cavitary defects with less than 50% host-bone contact with using TM cups, without structural support by augments or structural bone grafts, is a viable option.

Purpose: Pelvic discontinuity associated with bone loss is a complex challenge in acetabular revision surgery. Reconstruction with anti protrusion cages, Trabecular Metal (Zimmer, Warsaw, Indiana) cups and morselized bone (Cup-Cage) constructs is a relatively new technique used by the authors for the past 6 years. The purpose of the study was to examine the clinical outcome of these patients.

Method: Thirty-two consecutive acetabular revision reconstructions in 30 patients with pelvic discontinuity and bone loss treated by cup cage technique between January 2003 and September 2007 were reviewed. Average clinical and radiological follow up was 38.5 ± 19 months (range 12 – 68, median 34.5). Failure was defined as component migration > 5mm.

Results: In 29 (90.6%) patients there was no clinical or radiographic evidence indicative of loosening at latest follow up. Harris Hip Scores improved significantly (p< 0.001) from 46.6 ± 10.4 to 78.7 ± 10.4 at 2 year follow up. In 3 patients the construct migrated at 1 year post surgery. One construct was revised to anti protrusion cage with a structural graft while the other was revised to a large Trabecular Metal cup. The third patient is scheduled for revision. Complications included 2 dislocations, 1 infection and 1 partial peroneal nerve palsy. Two patients died due to unrelated reasons at 1 and 3 years post surgery, respectively.

Conclusion: Treatment of pelvic discontinuity by Cup-Cage construct is a reliable option based on preliminary results which suggest restoration of the pelvic mechanical stability. However, patients should be followed closely in order to detect cup migration until satisfactory bony ingrowth into the cup takes place.