Faculty Bibliography

BACKGROUND: Total knee arthroplasty (TKA) for juvenile idiopathic arthritis is rare but is nonetheless indicated for many patients with this disease. Few reports exist on the results of TKA in patients with juvenile idiopathic arthritis. QUESTIONS/PURPOSES: It was sought to determine (1) survivorship and (2) functional outcomes of TKAs in patients with juvenile idiopathic arthritis. METHODS: Results were combined from patients treated by experienced surgeons at five hospitals between 1979 and 2011. Two hundred nineteen patients (349 TKAs) were identified and contacted to survey their outcomes at a minimum followup of 2 years (mean, 12 +/- 8 years; range, 2-33 years). The average age at surgery was 28.9 +/- 9.7 years (range, 11-58 years). Data on revision surgery and ability to perform daily activities were collected. RESULTS: The 10-year survivorship was 95%, decreasing to 82% by 20 years. At latest followup, 31 of 349 TKAs (8.9%) had been revised for either polyethylene failure or loosening (18 TKAs), infection (four), stiffness (three), periprosthetic fractures (two), bilateral amputation for vascular reasons (two), patellar resurfacing (one), and instability (one). Walking tolerance was unlimited in 49%, five to 10 blocks in 23%, and less than five blocks in 28%. Eleven percent could not manage stairs, and another 59% depended on railings. A cane was used by 12% and crutches by 7%; 12% were wheelchair-dependent. CONCLUSIONS: TKA survivorship in patients with juvenile idiopathic arthritis was inferior to that typically seen in younger patients with osteoarthritis or even rheumatoid arthritis confirming results of earlier studies with smaller patient numbers. This is especially disconcerting because younger patients require better durability of their TKAs.

Tumor necrosis factor-alpha antagonists (anti-TNFalpha) have become increasingly more common as a treatment for rheu- matoid arthritis (RA). However, there has been an increased incidence of severe infections in patients taking anti-TNFalpha therapy. We present a case series of RA patients treated with anti-TNFalpha therapy that had previously underwent TJA and subsequently developed periprosthetic infections. All patients had a well-functioning implant for a period of 1 to14 years prior to the development of infection. Each patient underwent two to five different joint replacements, and four patients developed infection in multiple sites. The infections proved difficult to eradicate with four patients requiring multiple procedures, and one patient ultimately requiring a hemipelvectomy. This study suggests that periprosthetic infections acquired by patients on anti-TNFalpha therapy are challenging to eradi- cate and treat; highlighting the need for the establishment of guidelines for perioperative and long-term management of anti-TNFalpha therapy, and infection monitoring in joint replacement patients.

INTRODUCTION: Previous reports in the literature from Europe and Asia cite an increased burden on the local emergency departments and orthopaedic services during the operational period of the ice skating rinks. This retrospective observational study was undertaken in order to report the incidence, characteristic, and severity of injuries during a full season at a large urban ice skating rink, as well as to quantify the added burden the ice skating rink places on the local emergency department and the orthopaedic service. METHODS: All patients seen at our emergency room who sustained an injury at the neighboring "free" ice rink were identified over the 4-month period when it was open. The data collected included type of injury, demographics, and need for surgical treatment. RESULTS: Over this period, 118 patients were seen in our ED (of the 135 referrals from the ice rink logbook); Of these, 43 (38%) required an orthopaedic consult and were evenly divided into upper (22) and lower extremity injuries (21). Sixty-seven percent of the patients were adults, and the most common fractures were ankle and distal radius fractures. There were two open fractures of the distal radius seen in the older patients (both in patients > 50). Overall 32% of patients needed operative treatment. Of the non-orthopaedic injuries, the most common was head injury (25%). CONCLUSIONS: An ice-rink may be "free" but adds sig- nificant burden to the healthcare system, and these costs should be factored in by both the sponsoring body and the healthcare system for treatment of these additional patients.

A 71-year-old female with a history of right total hip arthroplasty presented with an enlarging pseudotumor. Pseudotumor is a known complication following metal-on-metal and metal-on-conventional polyethylene and metal-on-highly cross-linked polyethylene implants. Revision total hip arthroplasty following resection of pseudotumor has resulted in an increase in incidence of postoperative complications. Despite stable implants, these complications arise from the amount of soft tissue damage combined with the loss of tissue support around the resected hip. Our case is a clear example of a major complication, recurrent dislocation, following resection and revision surgery.

Optimizing perioperative care to provide maximum benefit at minimum cost may be best achieved using a perioperative clinical pathway (PCP). Using our joint replacement surgical home (JSH) model PCP, we examined length of stay (LOS) following total joint arthroplasty (TJA) to evaluate patient care optimization. We reviewed a spectrum of clinical measurements in 190 consecutive patients who underwent TJA. Patients who had surgery earlier in the week and who were earlier cases of the day had a significantly lower LOS than patients whose cases started both later in the week and later in the day. Patients discharged home had significantly lower LOS than those discharged to a secondary care facility. Patients who received regional versus general anesthesia had a significantly lower LOS. Scheduling patients discharged to home and who will likely receive regional anesthesia for the earliest morning slot and earlier in the week may help decrease overall LOS.

BACKGROUND: The numbers of people requiring total arthroplasty is expected to increase substantially over the next two decades. However, increasing costs and new payment models in the USA have created a sustainability gap. Ad hoc interventions have reported marginal cost reduction, but it has become clear that sustainability lies only in complete restructuring of care delivery. The Perioperative Surgical Home (PSH) model, a patient-centered and physician-led multidisciplinary system of coordinated care, was implemented at UC Irvine Health in 2012 for patients undergoing primary elective total knee arthroplasty (TKA) or total hip arthroplasty (THA). This observational study examines the costs associated with this initiative. METHODS: The direct cost of materials and services (excluding professional fees and implants) for a random index sample following the Total Joint-PSH pathway was used to calculate per diem cost. Cost of orthopedic implants was calculated based on audit-verified direct cost data. Operating room and post-anesthesia care unit time-based costs were calculated for each case and analyzed for variation. Benchmark cost data were obtained from literature search. Data are presented as mean +/- SD (coefficient of variation) where possible. RESULTS: Total per diem cost was $10,042 +/- 1,305 (13%) for TKA and $9,952 +/- 1,294 (13%) for THA. Literature-reported benchmark per diem cost was $17,588 for TKA and $16,267 for THA. Implant cost was $7,482 +/- 4,050 (54%) for TKA and $9869 +/- 1,549 (16%) for THA. Total hospital cost was $17,894 +/- 4,270 (24%) for TKA and $20,281 +/- 2,057 (10%) for THA. In-room to incision time cost was $1,263 +/- 100 (8%) for TKA and $1,341 +/- 145 (11%) for THA. Surgery time cost was $1,558 +/- 290 (19%) for TKA and $1,930 +/- 374 (19%) for THA. Post-anesthesia care unit time cost was $507 +/- 187 (36%) for TKA and $557 +/- 302 (54%) for THA. CONCLUSIONS: Direct hospital costs were driven substantially below USA benchmark levels using the Total Joint-PSH pathway. The incremental benefit of each step in the coordinated care pathway is manifested as a lower average length of stay. We identified excessive variation in the cost of implants and post-anesthesia care.

Two-stage revision has been shown to be the most successful treatment in eradicating deep infection following total hiparthroplasty. We identified 62 patients treated by a two-stage revision. We defined "successful revision" as negative intraoperative cultures and no further infection-related procedure. We defined "eradication of infection" on the basis of negative cultures and clinical diagnosis at least one year after 2(nd) stage procedure. After a mean follow up of 2.7 years, eradication of the infection was documented in 91.1%, and a successful two-stage revision in 85.7% of patients. We observed no association between higher pre-reimplantation levels of ESR and C-reactive protein and lower likelihood of successful two-stage revision. We found an association between a history of another previous infected prosthetic joint and a failed 2(nd) stage procedure. Failure to achieve eradication of infection and successful two-stage revision occurs infrequently. Patients with prior history of a previous prosthetic joint infection are at higher risk of failure.

The goal of this study was to evaluate the efficacy of arthroscopic lysis of adhesions after total knee arthroplasty (TKA) in improving range of motion (ROM) and providing an improvement in knee function. The authors retrospectively examined 19 patients who underwent arthroscopic lysis of adhesions following TKA due to poor ROM. The criterion for lysis was the inability to flex to 90 degrees at 3 months. All patients were followed for at least 2 years after lysis. Patient demographics, postoperative and follow-up ROM,number of prior surgeries, Knee Society Scores, and Western Ontario and McMaster Universities Arthritis Index (WOMAC) functional scores were collected. Average ROM increased from 75.37 degrees preoperatively to 98.95 degrees postoperatively. The authors found an association between preoperative knee score and change in ROM between pre-arthroscopic lysis and ROM at final follow-up (P=.0188). When the authors examined the relationship between patient body mass index (BMI) and change in ROM,they found that patients with a BMI higher than 30 kg/m2 had a change of 26.44 degrees compared with patients with a BMI lower than 30 kg/m2, who had a change of only 8.75 degrees . A strong association was found between patient height and change in ROM and final ROM achieved (P=.0062 and .0032, respectively). The authors report a successful outcome among study patients. Furthermore, they found an association between patient height, BMI, and preoperative knee score and the improvement achieved after arthroscopic lysis of adhesions following TKA. The current study's results are comparable with those of published results. The authors recommend arthroscopic lysis of adhesions as a treatment option for stiff knees after TKA that fails after at least 3 months of nonoperative treatment.

INTRODUCTION: Total knee arthroplasty (TKA) is the preferred surgical treatment for end-stage osteoarthritis. However, substantial numbers of patients still experience poor outcomes. Consequently, it is important to identify which patient characteristics are predictive of outcomes in order to guide clinical decisions. Our hypothesis is that preoperative patient-reported outcome measures and radiographic measures may help to predict TKA outcomes. METHODS: Using cohort data from the Osteoarthritis Initiative, we studied 172 patients who underwent TKA. For each patient, we compiled pre- and postoperative Western Ontario and McMaster University Arthritis Index (WOMAC) scores. Radiographs were measured for knee joint angles, femorotibial angles, anatomical lateral distal femoral angles, and anatomical medial proximal tibial angles; Kellgren and Lawrence (KL) grades were assigned to each compartment of the knee. All studied measurements were compared to WOMAC outcomes. RESULTS: Preoperative WOMAC disability, pain, and total scores were positively associated with postoperative WOMAC total scores (P = .010, P = .010, and P = .009, respectively) and were associated with improvement in WOMAC total scores (P < .001, P < .001, and P < .001, respectively). For radiographic measurements, preoperative joint angles were positively associated with improvements in postoperative WOMAC total scores (P = .044). Combined KL grades (medial and lateral compartments) were negatively correlated with postoperative WOMAC disability and pain scores (P = .045 and P = .044) and were positively correlated with improvements in WOMAC total scores (P = .001). CONCLUSIONS: All preoperative WOMAC scores demonstrated positive associations with postoperative WOMAC scores, while among the preoperative radiographic measurements only combined KL grades and joint angles showed any correlation with postoperative WOMAC scores. Higher preoperative KL grades and joint angles were associated with better (lower) postoperative WOMAC scores, demonstrating an inverse correlation.

Knee malalignment during total knee arthroplasty (TKA) is commonly classified as either varus or valgus on the basis of a standing anteroposterior radiograph. Computer-assisted surgery (CAS) navigation TKA provides precise dynamic evaluation of knee alignment throughout the full range of motion (FROM). The goal of this study was to classify patterns of CAS-generated knee deformity curves that match specific soft tissue contracture combinations. This can then be applied as an algorithm for soft tissue balancing on the basis of the preoperative knee deformity curve. Computer navigation-generated graphs from 65 consecutive TKA procedures performed by a single surgeon were analyzed. A stress-strain curve of the coronal alignment of the knee was recorded throughout FROM before bony resection. All graphs were classified into groups according to their pattern. Cadaveric knee models were then used to test the correlation between isolated and combined ligamentous contractures and identified CAS deformity curves. An analysis of the intraoperative knee alignment graphs revealed four distinct patterns of coronal deformity on the basis of intraoperative data: 13% diagonal, 18.5% C-shaped, 43.5% comma shaped, and 25% S-shaped. Each represents the change in varus and valgus alignment during FROM. All patterns were reproduced with cadaveric knees by recreating specific contracture constellations. A tight posterior capsule gave an S-shaped curve, a tight lateral collateral ligament gave a C-shaped curve, tight medial collateral ligament gave a diagonal curve, and a tight posterior lateral corner gave a comma-shaped curve. Release of the specific contractures resulted in correction of all patterns of deformity as measured by CAS. We propose a new classification system for coronal plane knee deformity throughout FROM. This system intends to match individual and combined soft tissue pathological contractures to specific stress-strain curves obtained through routine knee CAS preparation. This classification system may provide surgeons with a general guide for soft tissue balancing during computer-navigated TKA.