INTRODUCTION: Range of motion following TKA is a commonly assessed and important outcome parameter. The reported knee ROM is often measured using manual goniometers. The accuracy of goniometer in measuring ROM of the knee is not known. We compared the knee ROM measured with a manual goniometer and compared that to measurements obtained from computer assisted navigation system.

METHODS: This prospective ongoing study has so far recruited 60 patients (71 knees) undergoing TKA by a single surgeon. Measurements of the ROM were performed intraoperatively using a 14 inch 360° Nexgen Baseline® goniometer, validated by physical therapists, and the Stryker knee navigation system^™. Consistent anatomical landmarks were used to obtain flexion and extension measurements. Each goniometer and navigation measurement was performed twice by the same reader.

RESULTS: Goniometer was more inaccurate in measuring the knee ROM than the navigation. There was a 5.07° difference between two measurements obtained with the goniometer compared to a mean discrepancy of 1.15° using the navigation system. Further, the ROM measured by navigation was on average 13.9° larger than that measured by the goniometer. BMI affected the ROM recording obtained by both the goniometer and the navigation system.

DISCUSSION AND CONCLUSION: This study indicates that goniometer is not an accurate tool for measurements of knee ROM as there is a marked discrepancy between two goniometer readings. The navigation system seemed to produce more consistent, but markedly higher, readings than a manual goniometer. Reported results on knee ROM in the literature need to be interpreted with caution and scrutinized for potential inaccuracy of the measuring tool.

Background: Total joint arthroplasty (TJA) is a successful procedure. With the demographic tendency towards an elderly society and a relatively high prevalence of arthritis, the number of joint replacement in the US will increase dramatically in the upcoming years. The orthopaedic surgeons need to be aware of the various types of complications in the early hospital setting associated with elective TJA.

Methods: This prospective study reviewed the systemic and local early complications occurring after 13133 TJA which included 7,438 hip arthroplasties (6,010 primary and 1,428 revisions) and 5,695 knee replacements (4,944 primary and 751 revisions). A standardized and detailed form intended to capture all medical and orthopedic complications was devised, plus a full-time research fellow was dedicated to this study. The hospital course of every patient was followed on a daily basis closely. The circumstances leading to the complications and the details of the therapeutic intervention for each complication were recorded.

Results: In general the incidences of complications were higher following TKA compared to THA. There was 26(0.19%) deaths in the cohort that occurred within 10 days after surgery. 329 major (life threatening) complications occurred in the cohort that included myocardial infarction (36), hypotensive crisis (11), pulmonary embolus (145), tachyarrhythmia (93), pulmonary edema (10), acute renal failure (24), stroke (6), bowel obstruction or perforation (3), and pneumothroax (1). There were 37 major local complications. 301 (91%) of these complications occurred within 4 days of index surgery. There were 453 minor systemic complications, mostly related to anemia, and 99 minor local complications in this cohort.

Conclusions: Total joint arthroplasty despite its success can be associated with serious and life threatening complications. The introduction of MIS surgery and the potential for very early discharge of patients undergoing arthroplasty needs to be scrutinized in light of these findings.

Introduction: Management of bone loss during revision total knee arthroplasty (TKA) can be challenging. The degree and location of bone loss often dictates the type of prosthesis that can be utilized during revision surgery. The aim of this prospective study was to determine if plain radiographs are adequate in assessing the degree of bone loss around TKA and identify the limitations of plain radiographs for this purpose, if any.

Methods: 205 patients undergoing revision TKA at our institution were included. The indication for revision was aseptic failure in 120 patients and septic failure in the remaining patients. The plain radiographs were evaluated by a research fellow and the attending surgeon. The degree and the location of bone loss around the TKA was determined using the UPenn Bone Loss chart. The degree of real bone loss was then determined intraoperatively.

Results: The predicted amount of bone loss for the tibia based on the AP (p=0.136) and lateral (p=0.702) radiographs correlated well with the intraoperative findings. However, plain radio-graphs underestimated the degree of bone loss around femur, particularly the condyles (p=0.005).

Discussion: Reconstructive surgeons performing revision TKA need to be aware of the limitations of routine radiographs in assessing the degree of bone loss around the femoral component. Hence, patients undergoing revision TKA with suspected bone loss may need to be evaluated by additional imaging techniques and/or alternative reconstructive options need to be available to deal with greater than expected degree of bone loss intraoperatively.