Less pain reported 5 years after cementless compared to cemented unicompartmental knee replacement: an analysis of pain, neuropathy, and co‐morbidity scores

Abstract

Purpose To compare patient-reported pain scores and assess the influence of neuropathy and co-morbidity, on knee pain following cemented and cementless medial unicompartmental knee replacement (UKR) 5 years after surgery. Method In this longitudinal study, 262 cemented and 262 cementless Oxford UKR performed for the same indications and with the same techniques were recruited. Patients were reviewed at five years, evaluating patient-reported pain and association with clinical outcomes. Intermittent and Constant Osteoarthritis Pain (ICOAP), PainDETECT (PD), Charnley score, Oxford Knee Score (OKS) and American Knee Society Score (AKSS) were compared. Results In both cohorts, intermittent pain was more common than constant pain (47% vs 21%). Cementless knees reported significantly less pain than cemented (ICOAP-Total 5/100 vs 11/100, p < 0.0001). A greater proportion of cementless knees experienced no pain at all (ICOAP = 0/100, 61% vs 43%, p < 0.0001) and 75% fewer experienced severe or extreme pain. Pain sub-scores in PD, OKS and AKSS follow this trend. Pain was unlikely to be neuropathic (PD positive: 5.26%), but patients reporting high levels of ‘strongest’ pain were three times more likely to be neuropathic. Patients with co-morbidities (Charnley C) experienced greater pain than those without (Charnley A+B) across all knee-specific scores, despite scores being knee specific. Conclusion Both cemented and cementless UKR in this study had substantially less pain than that reported in literature following TKR. Cementless UKR had significantly less pain than cemented UKR in all scores. Two-thirds of patients with a cementless UKR had no pain at all at 5 years, and pain experienced was most likely to be mild and intermittent with no patients in severe or extreme pain. Patients with cementless UKR that had higher levels of pain were more likely to have co-morbidity or evidence or neuropathic pain. It is unclear why cementless UKR have less pain than cemented; further study is necessary.

Unicompartmental knee replacement: controversies and technical considerations

“…Furthermore, regarding the extent of migration, Campi et al [ 115 ] and Kendrick et al [ 116 ] both reported no significant differences between the two components. In regard to pain, both cemented and cementless have profoundly decreased pain following UKR; however, cementless had significantly less pain than cemented UKR in all scores (Intermittent and Constant Osteoarthritis Pain [ICOAP], PainDETECT [PD], Charnley score, Oxford Knee Score [OKS] and American Knee Society Score [AKSS]) [ 117 ].…”

Microporous titanium and hydroxyapatite improve fixation of the tibial wall in unicompartmental knee replacement

“…Pain is relatively common early after all types of knee replacement, and in a few patients, it may persist [12,14,16]. Following UKR, if early pain occurs, it is usually anteromedial about 2 cm below the tibial component.…”

“…Early randomised studies comparing cemented and cementless fixation found no difference in outcome scores but had small sample sizes and were underpowered in assessing outcome scores [6]. A much larger comparative cohort study of 546 patients has shown that at 5 years, cementless components were more likely to have no pain at all reported (61% vs. 43%) and less likely to have substantial pain reported (0.41% vs. 4.6%) compared to cemented components [12]. This may be because they are achieving a better mechanical bond between the tibial component wall and the tibial eminence.…”