Knee Arthroplasty After Subchondroplasty: Early Results, Complications, and Technical Challenges.

BACKGROUND: Calcium phosphate bone substitutes (CPBS) are commonly used to augment and repair bone voids and defects after fractures around the knee joint. The purpose of this study was to determine whether prior arthroscopic application of a CPBS, for repair of magnetic resonance imaging-identified subchondral fractures associated with osteoarthritis (procedure referred to as subchondroplasty) adversely affected the performance and/or outcome of subsequent knee arthroplasty. METHODS: Twenty-two patients who had arthroscopic repair of a periarticular fracture combined with use of a CPBS who later had knee arthroplasty were identified. Average follow-up for study patients was 23.5 months (range 12-52 months). These patients were matched demographically and for follow-up duration in a 2:1 ratio to a group of control subjects undergoing arthroplasty who had not undergone prior surgery. RESULTS: Technical challenges related to surgical performance, clinical outcomes, and complications were determined for both the groups. At most recent follow-up, study patients had an average Oxford score of 40.6 (range, 25-48) compared with control subjects with an average score of 40.1 (range, 12-48). There was no difference in complications or surgical complexity between groups, and only standard primary components were used. CONCLUSION: The results of our study suggest that prior arthroscopic repair combined with CPBS of periarticular fractures around the knee does not compromise the early outcomes and surgical performance or increase complications related to subsequent arthroplasty. However, longer follow-up of these patients is warranted to confirm that implant durability remains uncompromised.

Incidence of Infection and Inhospital Mortality in Patients With Chronic Renal Failure After Total Joint Arthroplasty.

BACKGROUND: Patients with chronic renal failure (CRF) may require total joint arthroplasty (TJA) to treat degenerative joint disease, fractures, osteonecrosis, or amyloid arthropathy. There have been conflicting results, however, regarding outcomes of TJA in patients with chronic renal disease. The aim of this case-controlled study was to determine the outcome of TJA in patients with CRF, with particular interest in the incidence of infections and inhospital mortality. METHODS: We queried our electronic database to determine which patients among the 29,389 TJAs performed at our institution between January 2000 and June 2012 had a diagnosis of CRF. A total of 359 CRF patients were identified and matched for procedure, gender, age (±4 years), date of surgery (±2 years), and body mass index (±5 kg/m2) in a 2:1 ratio to 718 control patients. RESULTS: The incidence of infection and inhospital mortality was not significantly different between the nondialysis CRF patients and controls, whereas it was significantly higher in dialysis-dependent end-stage renal failure patients compared to controls. Of the 50 CRF patients receiving hemodialysis, 10 (20%) developed surgical site infection, of which 4 (8%) were periprosthetic joint infection, and 4 (8%) died during hospital stay. The odds ratio for infection in the dialysis group was 7.54 (95% confidence interval: 2.83-20.12) and 10.46 (95% confidence interval: 1.67-65.34) for the inhospital mortality. CONCLUSION: We conclude that end-stage renal failure patients receiving hemodialysis have higher postoperative infection and inhospital mortality rates after an elective TJA procedure, whereas nondialysis CRF patients have similar outcomes compared with the general TJA population.

Modular Polyethylene Inserts for Total Knee Arthroplasty: Can Surgeons Detect 1-mm Thickness Increments?

BACKGROUND: Some manufacturers have introduced polyethylene (PE) inserts in 1-mm increment thickness options to allow for finer adjustments in total knee arthroplasty kinematics. METHODS: Two surgeons with extensive experience performed 88 total knee arthroplasties using implants with 1-mm PE inserts. After trial components were inserted and the optimal PE thickness was selected, the insert was removed and a trial insert size was randomly chosen from opaque envelopes (1-mm smaller, same size, and 1-mm larger). The knee was re-examined and the surgeon determined which size PE had been placed. RESULTS: Surgeons reliably determined insert thicknesses in 62.5% (55 of 88; P = .050) of trials. Surgeons were not able to accurately detect 1-mm incremental changes of trial PE implants on a consistent basis. CONCLUSION: The potential clinical usefulness of this concept should be further evaluated.

The Effect of Implementing a Multimodal Approach on the Rates of Periprosthetic Joint Infection After Total Joint Arthroplasty.

INTRODUCTION: We examined the efficacy of implementing a multimodal program aimed at reducing the incidence of periprosthetic joint infection (PJI) after total joint arthroplasty (TJA) in a mid-size community hospital. METHODS: An infection reduction committee (IRC) was formed at our hospital in November 2010. The IRC consisted of two orthopaedic surgeons, an infectious disease specialist, an internist with extensive experience in perioperative medical management of TJA patients, an anesthesiologist, the hospital infection control nurse, and two additional nurses. Their goals were to 1) evaluate the current incidence of PJI at our institution, compare it with the reported national data, and consider measures already in place directed at preventing PJI; 2) review and routinely evaluate recently published studies or information obtained from continuing medical education events related to PJI to determine if practice changes were warranted (based on intervention efficacy, cost, and safety) and then develop a plan to implement appropriate alterations in perioperative protocols using a multimodal strategy; and 3) evaluate the effect and safety of newly-introduced infection reduction strategies on the incidence of PJI. RESULTS: In 2008, the incidence of PJI at our hospital was 1.0%. By 2013, this rate had reduced to 0.4%. In absolute numbers, in 2009, 20 of 1,150 TJAs developed a PJI in the 12-month period following partial, primary, or revision TJA. In 2013, PJI occurred in only 4 of 1,053 TJA patients. CONCLUSION: We found that formation of an IRC focused on evaluating and implementing strategies to reduce PJI following TJA can be effective.

Serum Metal Ion Levels Following Total Hip Arthroplasty With Modular Dual Mobility Components.

Dual mobility acetabular components can reduce the incidence of total hip arthroplasty (THA) instability. Modular dual mobility (MDM) components facilitate acetabular component implantation. However, corrosion can occur at modular junctions. Serum cobalt and chromium levels and Oxford scores were obtained at minimum two year follow-up for 100 consecutive patients who had THA with MDM components. Average Oxford score was 43 (range 13-48). Average serum cobalt and chromium values were 0.7 mcg/L (range, 0.0 to 7.0) and 0.6 mcg/L (range, 0.1 to 2.7), respectively. MARS MRI was performed for four patients with pain and elevated serum cobalt levels. Two of these studies were consistent with adverse local tissue reaction. We recommend use of MDM implants in only patients at high risk for dislocation following THA.