SA Orthopaedic Journal
On-line version ISSN 2309-8309
Print version ISSN 1681-150X
HASSABALLA, MA; GBEJUADE, HO; PORTEOUS, AJ and MURRAY, JR. The effect of joint line restoration on kneeling ability after primary total knee replacement. SA orthop. j. [online]. 2012, vol.11, n.3, pp.79-83. ISSN 2309-8309.
BACKGROUND: Total knee replacement (TKR) surgery has become one of the commonest orthopaedic procedures undertaken. Pain relief and restoration of function are two major expectations following knee arthroplasty. Kneeling is a knee function required for many types of occupation and activities of daily living, making its restoration following knee arthroplasty essential. Restoration of joint line position is a surgical factor that has been reported to have an important impact on functional outcome after TKR. MATERIALS AND METHODS: We reviewed 100 (43 males and 57 females; with a mean patient age of 71 years) consecutive cemented Kinemax Plus TKRs (Stryker, Newbury, UK) performed in our unit with a minimum follow-up of two years. Joint line measurements were made on the pre-operative and post-operative X-rays. The kneeling ability component of the Oxford Knee Score questionnaire was analysed for all patients. The pre- and post-operative Oxford Knee Scores were prospectively recorded. Patients' ranges of movement (ROM) were measured. RESULTS: The mean pre-operative ROM for the group was 82° (std ± 15). Post-operatively, the mean ROM for the whole group was 109° (std ± 8). A joint line within ± 5 mm of the pre-operative measurement was considered 'restored' and more than 5 mm was considered 'elevated. Seventy-five per cent of patients had the joint line restored within 5 mm of their native joint line post-operatively. The mean ROM for restored and elevated groups was 116° and 108° respectively. This difference was statistically significant (P < 0.01). However, there was no significant difference in the total Oxford Knee Score between the groups. CONCLUSION: Seventy-five per cent of cases in this study showed a restored joint line position. In this group, the ROM was better than in the group with elevated joint line (116° for restored joint line versus 108° for elevated joint line). This study showed that restoring the joint line had a positive impact on the post-operative ROM and kneeling ability. However, kneeling ability can be affected by other factors and further studies are necessary to fully investigate this complex function of the knee joint.
Keywords : kneeling; total knee replacement; joint line restoration; range of motion.