The effect of stem design on end of stem pain in revision TKA

A consecutive series of revision TKA performed for aseptic loosening was evaluated with a Knee Society clinical score, radiographic assessment and satisfaction questionnaire. Patients also completed a pain drawing of their lower extremity regarding the location and severity of any pain they experienced at a minimum two-year follow-up. Pain localized to the diaphyseal region of the femur or tibia was defined as end of stem pain. Two stem designs were used: a solid, fluted cobalt chrome stem was utilized in 112 cases (224 stems) and a slotted titanium stem was utilized in 31 cases (62 stems). End of stem pain was associated with 42 of 224 (18.8%) solid cobalt chrome stems. A significantly lower incidence of end of stem pain was associated with slotted titanium stems (five of 62 stems, 8.1%; p<0.05). Symptoms were intermittent, and activity related in all but two cases, and none were severe enough to require component revision. The presence of end of stem pain did appear to be clinically significant, since patients with this finding were more likely to be only somewhat satisfied or dissatisfied with their degree of pain relief, compared to those without end of stem pain (18% vs. 7%, p<0.05). Stem design does appear to impact the incidence of end of stem pain in revision TKA.