Optimal Timing for Hemoglobin Concentration Determination after Total Knee Arthroplasty: Day 1 versus Day 2

PURPOSE: Postoperative hemoglobin (Hb) determination remains an essential parameter for quantifying blood loss following total knee replacement (TKR) surgery and guiding transfusion practice. In this study we aimed to ascertain the optimal timing for Hb determination postoperatively and assess its relationship to serum hematocrit (Hct). MATERIALS AND METHODS: This was a retrospective cohort analysis of 61 consecutive patients undergoing preoperative, day 1 and day 2 Hb and Hct concentration determination following TKR surgery. This was a single centre study in the United Kingdom. RESULTS: The mean fall in Hb concentration at day 1 was 2.9 g/dL in comparison to 3.3 g/dL at day 2. This indicated a significant difference of 0.39 g/dL (p=0.023). A total of 5 patients required blood transfusions following day 2 Hb determination. Postoperative Hct values varied in close relation with the Hb concentration with no significant differences demonstrated. Our study reveals a significant change between day 1 and day 2 Hb concentrations following TKR surgery, with no significant differing information provided through Hct determination. CONCLUSIONS: Our results support the use of delayed routine testing at day 2 following surgery as it is likely to more accurately reflect ongoing hidden blood loss into the joint cavity and within soft tissue planes.

Are "Patellofemoral Symptoms" Truly Related to the Patellofemoral Joint?

PURPOSE: The pattern of symptoms of knee osteoarthritis has been thought to be indicative of specific compartment involvement. This study investigated whether there was a true correlation between patellofemoral joint (PFJ) symptoms and unicompartmental patellofemoral arthritis. MATERIALS AND METHODS: A prospective analysis of 34 patients rendered to be suffering from PFJ osteoarthritis and subsequently undergoing unicompartmental patellofemoral arthroplasty (PFA) was performed. A control cohort of 32 patients suffering from medial tibiofemoral joint (MTFJ) osteoarthritis was included in the analysis. Four questions derived from the Oxford knee score questionnaire, traditionally deemed to be indicative of PFJ osteoarthritis, were combined to create a PFJ subscore and statistically analyzed for their potential relationship with PFJ osteoarthritis and outcomes following PFA. RESULTS: The PFJ subscore indicated slightly worse pathology in patients undergoing PFA compared to MTFJ replacement, but the difference was not significant (9.7 and 9.6, respectively; p=0.851). The improvement in PFJ symptoms was higher in those undergoing PFA compared to MTFJ surgery; however, the difference was not statistically significant (3.7 and 2.2 respectively, p=0.074). CONCLUSIONS: We were unable to prove that these symptoms were predictive of PFJ pathology in the preoperative setting, nor were they useful in interpreting which symptoms would likely improve following PFA.