Robotic Arthroplasty Clinical and cost Effectiveness Randomised controlled trial (RACER-knee): a study protocol

INTRODUCTION

Robotic-assisted knee replacement systems have been introduced to healthcare services worldwide in an effort to improve clinical outcomes for people, although high-quality evidence that they are clinically, or cost-effective remains sparse. Robotic-arm systems may improve surgical accuracy and could contribute to reduced pain, improved function and lower overall cost of total knee replacement (TKR) surgery. However, TKR with conventional instruments may be just as effective and may be quicker and cheaper. There is a need for a robust evaluation of this technology, including cost-effectiveness analyses using both within-trial and modelling approaches. This trial will compare robotic-assisted against conventional TKR to provide high-quality evidence on whether robotic-assisted knee replacement is beneficial to patients and cost-effective for healthcare systems.

METHODS AND ANALYSIS

The Robotic Arthroplasty Clinical and cost Effectiveness Randomised controlled trial-Knee is a multicentre, participant-assessor blinded, randomised controlled trial to evaluate the clinical and cost-effectiveness of robotic-assisted TKR compared with TKR using conventional instruments. A total of 332 participants will be randomised (1:1) to provide 90% power for a 12-point difference in the primary outcome measure; the Forgotten Joint Score at 12 months postrandomisation. Allocation concealment will be achieved using computer-based randomisation performed on the day of surgery and methods for blinding will include sham incisions for marker clusters and blinded operation notes. The primary analysis will adhere to the intention-to-treat principle. Results will be reported in line with the Consolidated Standards of Reporting Trials statement. A parallel study will collect data on the learning effects associated with robotic-arm systems.

ETHICS AND DISSEMINATION

The trial has been approved by an ethics committee for patient participation (East Midlands-Nottingham 2 Research Ethics Committee, 29 July 2020. NRES number: 20/EM/0159). All results from the study will be disseminated using peer-reviewed publications, presentations at international conferences, lay summaries and social media as appropriate.

TRIAL REGISTRATION NUMBER

ISRCTN27624068.

Does degree of trochlear dysplasia and position of femoral tunnel influence outcome after medial patellofemoral ligament reconstruction?

BACKGROUND

The medial patellofemoral ligament (MPFL) is the main restraining force against lateral patellar displacement. It is disrupted after patellar subluxation or dislocation. Reconstruction of the MPFL is frequently performed when nonoperative management fails and the patient experiences recurrent patellar dislocation.

PURPOSE

To determine the relationship between the degree of trochlear dysplasia and femoral tunnel position and outcome after MPFL reconstruction.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 68 patients (72 knees) with recurrent dislocation of the patella underwent MPFL reconstruction. The mean follow-up was 31.3 months (range, 13-72 months). Clinical and functional outcomes were recorded using the Kujala, Lysholm, and Tegner scores. Postoperative complications, participation in sporting activity, and overall patient satisfaction were determined. Radiographs were analyzed to evaluate congruence angle, lateral patellofemoral angle, patellar height, trochlear dysplasia, trochlear boss height, and position of the femoral tunnel.

RESULTS

The mean Kujala, Lysholm, and Tegner scores postoperatively were 76.2, 73.8, and 3.6, respectively (n = 61). The mean congruence angle (n = 30) improved from 22.5° to 1.0° postoperatively (P = .000038), the lateral patellofemoral angle (n = 30) improved from 7.4° to 7.8° postoperatively (P = .048), and the patellar height (n = 46) using the Caton-Deschamps method improved from 1.1 to 1.0 postoperatively (P = .000016). Mild trochlear dysplasia grade A/B was found in 89% of patients (n = 54), and 11% of patients (n = 7) had severe grade C/D dysplasia. The mean distance from the anatomic insertion of the MPFL to the center of the tunnel was 9.3 mm (range, 0.5-28.2 mm), with 71.7% thought to be within 10 mm of the anatomic position defined by Schottle (n = 46). When patients with high-grade trochlear dysplasia were excluded, anatomically placed femoral tunnels demonstrated significantly better clinical scores than did tunnels not placed anatomically (Kujala score, P = .028; Lysholm score, P = .012). A multivariate logistic regression analysis also demonstrated that the distance of the femoral tunnel from the anatomic position predicted clinical outcome (Kujala score, P = .043; Lysholm score, P = .028). All of the patients with severe trochlear dysplasia (n = 7) suffered from recurrent dislocations postoperatively, compared with only 9.3% of patients (n = 5) with mild trochlear dysplasia (P = .0001). Four patients had patellar fractures postoperatively. Of patients with mild dysplasia, 83% were either very satisfied or satisfied with the outcome of their surgery compared with only 57% with severe dysplasia (P = .05). Of patients with mild trochlear dysplasia, 56% returned to sport postoperatively compared with only 43% of patients with severe trochlear dysplasia (P = .526).

CONCLUSION

This study demonstrates the importance of restoration of the anatomic insertion point of the MPFL when performing MPFL reconstruction and proposes that this procedure should not be performed in isolation in patients with high-grade trochlear dysplasia.

The changing epidemiology of acute and subacute haematogenous osteomyelitis in children

We have reviewed the incidence of bacteriologically or radiologically confirmed acute haematogenous osteomyelitis in children under 13 years of age resident in the area of the Greater Glasgow Health Board between 1990 and 1997. In this period there was a fall of 44% in the incidence of both acute and subacute osteomyelitis, mainly involving the acute form (p = 0.005). This mirrors the decline of just over 50% previously reported in the same population between 1970 and 1990. Using multiple regression analysis a decline in incidence of 0.185 cases per 100,000 population per year was calculated for the 28-year period (p < 0.001). Staphylococcus was the most commonly isolated pathogen (70%). Only 20% of patients required surgery and there was a low rate of complications (10%). In general, patients with a subacute presentation followed a benign course and there were no complications or long-term sequelae in this group. Haematogenous osteomyelitis in children in this area is becoming a rare disease with an annual incidence of 2.9 new cases per 100,000 population per year.

Dorsal wedge osteotomy in the treatment of hallux rigidus

The results of 18 dorsal wedge osteotomies in the treatment of hallux rigidus are presented. Patients were retrospectively interviewed and examined, and an assessment was made in a number of key functional areas. Good or excellent results were obtained in 14 or 18 cases at a mean follow-up time of 4 years with only one patient requiring further surgery. Pain (p = 0.00014), activity levels (p = 0.0019), footwear difficulties (p = 0.0016), and joint range of motion (p = 0.0001) were all significantly improved; tiptoeing was the only activity assessed (p = 0.23) for which the improvement was not significant. These results compare well with other published series. We recommend dorsal wedge osteotomy as a useful alternative in the treatment of hallux rigidus.

Diabetes and trigger finger

Trigger finger is a stenosing tenovaginitis in which there is a constriction of the annular sheath associated with a nodule in the digital flexor tendon. Clinically this can present as triggering or snapping of the nodule as it passes through the tight constricting tendon sheath. Although many triggering fingers settle spontaneously, and others respond to local anesthetic and steroid injection, others require surgical decompression. The association between diabetes and trigger finger, although not widely known, has been described and forms part of the "diabetic hand syndrome". We studied 100 adult patients in the group that required surgery. Eighteen of the 100 patients were diabetic with six insulin dependent diabetics (IDDM) and 12 non-insulin dependent diabetics (NIDDM). In the current climate of day case surgery this has significant implications both for the management of known diabetics as well as the preoperative detection of those with the condition.

Bier's block: a change of injection site

Bier's block or intravenous regional anesthesia is a well-proven technique that is useful in the traumatic setting to provide upper limb anesthesia in the manipulation of distal radial fractures. In this situation, the traditional injection site in the dorsum of the hand can present difficulties with subsequent plaster application and with venous access caused by swelling or pain. One hundred patients were randomly allocated into two groups of 50. The first group was injected into the dorsum of the hand and the second into the antecubital fossa, in each case on the injured side. Effectiveness of anesthesia at both the fractures site and the cuff was assessed using a visual analog scale. Results analyzed using Student's t test, showed no difference in anesthesia between the two groups. In addition, there were fewer technical problems associated with venous access and subsequent plaster application in the antecubital fossa group.