Extended duration regional analgesia for total knee arthroplasty: a randomised controlled trial comparing five days to three days of continuous adductor canal ropivacaine infusion.

There is a growing body of evidence in favour of continuous adductor canal block (CACB) for total knee arthroplasty. However, there are no studies describing the optimal duration of the infusion. At our institution the usual practice was to stop the infusion on day three. Our hypothesis was that extending the infusion to five days would improve analgesia and quality of recovery. A prospective, non-blinded, randomised trial was undertaken. Patients received a continuous infusion of 0.2% ropivacaine via an adductor canal catheter for either three or five days. Primary outcome was pain while walking during the 24-hour period up to day five (numeric rating scale from 0 to 10). The minimum clinically important difference was set at 1.5 on the numeric rating scale. Secondary outcome measures included quality of recovery, mobility, pain while walking on postoperative day six, Oxford Knee Scores, and complications. Eighty-six patients were recruited with 43 randomised to each group. Seventy-eight were analysed. Median pain scores reported on day five were significantly better in the intervention group (1 versus 3, P=0.003). Furthermore, quality of recovery (QOR-15) scores were significantly better in the intervention group (133.6 versus 123.4, P=0.017). No statistically significant difference between groups was identified for other secondary outcome measures. CACB prolonged to five days provides superior analgesia and a higher quality of recovery on postoperative days four and five compared to a three-day infusion. This benefit did not extend beyond the period of infusion.

Component alignment and clinical outcome following total knee arthroplasty: a randomised controlled trial comparing an intramedullary alignment system with patient-specific instrumentation.

AIMS: We conducted a randomised controlled trial to assess the accuracy of positioning and alignment of the components in total knee arthroplasty (TKA), comparing those undertaken using standard intramedullary cutting jigs and those with patient-specific instruments (PSI). PATIENTS AND METHODS: There were 64 TKAs in the standard group and 69 in the PSI group. The post-operative hip-knee-ankle (HKA) angle and positioning was investigated using CT scans. Deviation of > 3° from the planned position was regarded as an outlier. The operating time, Oxford Knee Scores (OKS) and Short Form-12 (SF-12) scores were recorded. RESULTS: There were 14 HKA-angle outliers (22%) in the standard group and nine (13%) in the PSI group (p = 0.251). The mean HKA-angle was 0.5° varus in the standard group and 0.2° varus in the PSI group (p = 0.492). The accuracy of alignment in the coronal and axial planes and the proportion of outliers was not different in the two groups. The femoral component was more flexed (p = 0.035) and there were significantly more tibial slope outliers (29% versus 13%) in the PSI group (p = 0.032). Operating time and the median three-month OKS were similar (p = 0.218 and p = 0.472, respectively). Physical and mental SF-12 scores were not significantly different at three months (p = 0.418 and p = 0.267, respectively) or at one year post-operatively (p = 0.114 and p = 0.569). The median one-year Oxford knee score was two points higher in the PSI group (p = 0.049). CONCLUSION: Compared with standard intramedullary jigs, the use of PSI did not significantly reduce the number of outliers or the mean operating time, nor did it clinically improve the accuracy of alignment or the median Oxford Knee Scores. Our data do not support the routine use of PSI when undertaking TKA. Cite this article: Bone Joint J 2016;98-B:1043-9.

A comparison of a less invasive piriformis-sparing approach versus the standard posterior approach to the hip: A randomised controlled trial.

We undertook a randomised controlled trial to compare the piriformis-sparing approach with the standard posterior approach used for total hip replacement (THR). We recruited 100 patients awaiting THR and randomly allocated them to either the piriformis-sparing approach or the standard posterior approach. Pre- and post-operative care programmes and rehabilitation regimes were identical for both groups. Observers were blinded to the allocation throughout; patients were blinded until the two-week assessment. Follow-up was at six weeks, three months, one year and two years. In all 11 patients died or were lost to follow-up. There was no significant difference between groups for any of the functional outcomes. However, for patients in the piriformis-sparing group there was a trend towards a better six-minute walk test at two weeks and greater patient satisfaction at six weeks. The acetabular components were less anteverted (p = 0.005) and had a lower mean inclination angle (p = 0.02) in the piriformis-sparing group. However, in both groups the mean component positions were within Lewinnek's safe zone. Surgeons perceived the piriformis-sparing approach to be significantly more difficult than the standard approach (p = 0.03), particularly in obese patients. In conclusion, performing THR through a shorter incision involving sparing piriformis is more difficult and only provides short-term benefits compared with the standard posterior approach.

A constrained acetabular component for recurrent dislocation.

We treated 34 patients with recurrent dislocation of the hip with a constrained acetabular component. Roentgen stereophotogrammetric analysis was performed to assess migration of the prosthesis. The mean clinical follow-up was 3.0 years (2.2 to 4.8) and the radiological follow-up was 2.7 years (2.0 to 4.8). At the latest review six patients had died and none was lost to follow-up. There were four acetabular revisions, three for aseptic loosening and one for deep infection. Another acetabular component was radiologically loose with progressive radiolucent lines in all Gruen zones and was awaiting revision. The overall rate of aseptic loosening was 11.8% (4 of 34). Roentgen stereophotogrammetric analysis in the non-revised components confirmed migration of up to 1.06 mm of translation and 2.32 degrees of rotation at 24 months. There was one case of dislocation and dissociation of the component in the same patient. Of the 34 patients, 33 (97.1%) had no further episodes of dislocation. The constrained acetabular component reported in our study was effective in all but one patient with instability of the hip, but the rate of aseptic loosening was higher than has been reported previously and requires further investigation.