Abstract
Introduction
Total knee arthroplasty is very successful although the clinical assessment and rated outcome does not always match the patients reported satisfaction. One reason for patient dissatisfaction is less than desired range of motion. Poor postoperative motion inhibits many functional activities and may create a perception of dysfunction. Early in the postoperative period when patients are having trouble regaining motion (usually 6–8 weeks), manipulation under anesthesia can be used to advance range of motion by manually lysing adhesions.
Comorbidities have been used as predictors for outcome in total knee arthroplasty in population health studies. Likewise, predicting which patients are most susceptible to early postoperative stiffness/manipulation would be valuable for patient education and to predict outcome.
Methods
Prospectively collected data was retrieved from the hospital's MARCQI database (Michigan Arthroplasty Collaborative Quality Initiative) for the years 2014–2018. There were 3098 primary total knees performed during the study period and 139 manipulations (4.44%). The registry specifically abstracts patients’ preoperative comorbidities, operative data, and 90-day postoperative complications.
Results
There were 2118 Cruciate Retaining/Cruciate Stabilized knees (105 MUA), 801 Posterior Stabilized (33), and 41 Total Stabilized/Hinge (1), 2160 knees were cemented (91) and 799 uncemented (48).
No differences were found between the manipulation and non-manipulation groups for gender, race, alcohol consumption, bleeding disorders, history of DVT or PE, Diabetes, or use of pre-op narcotics or anti-coagulents.
Patients undergoing manipulation were younger (67.2 vs. 63.8, p= 0.00001), had a lower BMI (32.6 vs. 30.9 p= 0.0007), and were more likely to be non or former (quit) smokers. There were no differences noted for the constraint of the component (cr/ps), or whether the implants were cemented or uncemented (35% vs. 27%, p= 0.064).
Conclusions
Understanding the risk for postoperative stiffness and the potential for manipulation is helpful in the preoperative period for patient education and outcome prediction. Assessing comorbidities and patient characteristics may help avoid the need for manipulations postoperatively. This patient cohort may be biased since the manipulations were not based on predetermined criteria. The cohort represents patients whose range of motion was poor enough to cause the surgeon to perform the procedure. The findings do however highlight a patient pool that was surprisingly at risk: younger, thinner, nonsmokers regardless the implant design or use of cement.
