Performance of medial pivot, posterior stabilized and rotating platform total knee arthroplasty based on anteroposterior stability and patient-reported outcome measures; a multicentre double-blinded randomized controlled trial of 210 knees.

BACKGROUND: Despite advancements in total knee arthroplasty (TKA), 10-20% of patients remain dissatisfied after surgery. Improved anteroposterior (AP) stability provided by medial pivot (MP) implants may theoretically lead to higher patient satisfaction. METHODS: AP stability and patient-reported outcome measures (PROMs) at one-year postsurgery were compared between patients who underwent TKA with MP- (n = 121), posterior stabilized (PS; n = 53) and rotating platform (RP; n = 57) implants in a double-blind multicentre randomized controlled trial (Dutch Trial Register: NL6856, 21-02-2018). AP stability was assessed at 30°, 60° and 90° of knee flexion using a KT-2000 arthrometer. PROMs were measured preoperative and one-year postsurgery. RESULTS: MP-TKA provided significant better AP stability at early flexion (30°) compared to PS- and RP-TKA (median [IQR]; 1.79 [1.14-2.77] mm vs. 3.31 [2.51-4.08] mm vs. 2.82 [1.80-4.03] mm, p < 0.001). Additionally, MP-TKA provided significant better AP stability at mid-flexion (60°) compared to PS-TKA (1.75 [1.23-2.36] mm vs. 2.14 [1.49-2.83] mm, p = 0.014). PROM improvements were comparable between implant designs. AP laxity of ≥ 4 mm at early flexion was independently of implant design associated with significantly worse Kujala scores. The incidence of ≥ 4 mm AP laxity at any knee angle was however not significantly different between implant designs. CONCLUSION: MP-, PS- and RP-TKA all provide excellent and comparable results. Although MP-TKA provided better AP stability at early flexion compared to PS- and RP-TKA, this was found to be unrelated to improved PROMs in favour of MP-TKA. More studies focusing on early and mid-flexion performance based differences between MP and other TKA designs are required to confirm our findings. Other non-implant related factors may play a more important role in the performance of TKA and are potentially worthwhile examining.

Do tibiofemoral contact point and posterior condylar offset influence outcome and range of motion in a mobile-bearing total knee arthroplasty?

PURPOSE: The posterior condylar offset (PCO) and the tibiofemoral contact point (CP) have been reported as important factors that can influence range of motion and clinical outcome after total knee arthroplasty. A mobile-bearing knee implant with an anterior posterior gliding insert would in theory be more sensitive for changes in PCO and CP. For this reason, we analysed the PCO and CP and the relation with outcome and range of motion in 132 patients from a prospectively documented cohort in this type of implant. METHODS: The prosthesis used was a posterior cruciate retaining AP gliding mobile-bearing total knee replacement (SAL II Sulzer Medica, Switzerland). In 132 knees, the pre- and postoperative PCO and postoperative CP were evaluated. Measurements were made on X-rays of the knee taken in approximately 90° of flexion and with less than 3-mm rotation of the femur condyles. The outcome parameters, range of motion (ROM) and the knee society score (KSS), for each knee were determined preoperatively and at 5-year follow-up. RESULTS: The mean KSS improved from 91 to 161 at 5-year follow-up (p < 0.001) and the mean ROM from 102 to 108 (p < 0.05). The mean PCO difference (postoperative PCO-preoperative PCO) was--0.05 mm (SD 2.15). The CP was on average 53.9% (SD 5.5%). ROM was different between the 3 PCO groups (p = 0.05): patients with 3 or more mm decrease in PCO had the best postoperative ROM (p = 0.047). There was no statistical difference between the postoperative ROM between patients with a stable PCO and those with an increased PCO. There was no correlation between the difference in PCO and the difference in ROM; R Pearson = -0.056. There was no difference in postoperative ROM or postoperative total KSS between CP <60% and CP >60%: p = 0.22, p = 0.99, for ROM and KSS, respectively. Scatter plots showed uniform clouds of values: increase or decrease in PCO and CP had no significant influence on ROM or KSS. CONCLUSION: The hypotheses that a stable PCO and a more natural CP increase postoperative ROM and improve clinical outcome could not be confirmed. On the contrary, a decreased PCO seemed to improve knee flexion. Furthermore, a relationship between PCO and CP could not be found. LEVEL OF EVIDENCE: Prospective cohort study, Level II.

Survey of prophylactic use of uterotonics in the third stage of labour in the Netherlands.

OBJECTIVE: aim of this study was to investigate current knowledge and practice regarding AMTSL in midwifery practices and obstetric departments in the Netherlands. DESIGN: web-based and postal questionnaire. SETTING: in August and September 2011 a questionnaire was sent to all midwifery practices and all obstetric departments in the Netherlands. PARTICIPANTS: all midwifery practices (528) and all obstetric departments (91) in the Netherlands. MEASUREMENTS AND FINDINGS: the response was 87.5%. Administering prophylactic uterotonics was seen as a component AMTSL by virtually all respondents; 96.1% of midwives and 98.8% of obstetricians. Cord clamping was found as a component of AMTSL by 87.4% of midwives and by 88.1% of obstetricians. Uterine massage was only seen as a component of AMTSL by 10% of the midwives and 20.2% of the obstetricians. Midwifery practices routinely administer oxytocin in 60.1% of births. Obstetric departments do so in 97.6% (p<0.01). Compared to 1995, the prophylactic use of oxytocin had increased in 2011 both by midwives (10-59.1%) and by obstetricians (55-96.4%) (p<0.01). KEY CONCLUSIONS: prophylactic administration of uterotonics directly after childbirth is perceived as the essential part of AMTSL. The administration of uterotonics has significantly increased in the last decade, but is not standard practice in the low-risk population supervised by midwives. IMPLICATIONS FOR PRACTICE: the evidence for prophylactic administration of uterotonics is convincing for women who are at high risk of PPH. Regarding the lack of evidence of AMTSL to prevent PPH in low risk (home) births, further research concerning low-risk (home) births, supervised by midwives in industrialised countries is indicated. A national guideline containing best practices concerning management of the third stage of labour supervised by midwives, should be composed and implemented.

The Self-Aligning knee prosthesis: clinical and radiological outcome and survival analysis at 5-year follow up.

The purpose of this study is to evaluate the clinical and radiological results and the survival of the SAL II mobile bearing knee prosthesis at 5-year follow up. Between February 1995 and March 1998 a total of 246 SAL II total knee arthroplasties were performed in 232 patients. The mean follow up was 5.0 years. Thirteen revisions had been carried out (5%). The mean total Knee Society Score increased from 88 preoperatively to 153 and 155 at 1 and 5 years follow up, respectively. The mean flexion angles were 106 degrees and 107 degrees pre- and postoperatively. None of the prostheses showed radiological loosening. No dislocations or subluxations of inserts were seen. The Kaplan-Meier cumulative survival is 95% for revision for any reason at 5.0 years, with a worst case scenario of 91%. The survival for aseptic loosening is 99%. The results of SAL II after a minimum follow up of 5 years are favourable and comparable with fixed bearing and other mobile bearing designs in terms of Knee Society Score and survival. Noteworthy are the good radiological results of this device which showed a good fixation of the prosthesis at 5 years.

The incidence of dislocation after primary total hip arthroplasty using posterior approach with posterior soft-tissue repair.

BACKGROUND: Dislocation after total hip arthroplasty (THA) is one of the most common major complications, and occurs more often through a posterior approach. We performed a retrospective study to determine the incidence of early dislocation and the relationship to the type of prosthesis and the surgeon's experience. METHODS: A group of 884 consecutive primary THAs (746 cemented and 138 cementless) approached through a posterior incision with repair of the posterior soft tissues was followed for a mean of 30 months. RESULTS: The overall dislocation rate was 1.36% (cemented: 1.1%; cementless: 2.9%). All dislocations were posterior and occurred within 6 months after surgery, 91% within 6 weeks. Dislocations were most common in rheumatoid patients (3.8%). Two revisions (0.23%) of the acetabular cup were performed for recurrent dislocations. The dislocation rate was not higher in the operations performed by less experienced surgeons. CONCLUSION: The early dislocation rate after primary THA through a posterior approach with repair of the posterior soft tissues was low, especially in cemented THA. Less experienced surgeons were not associated with a higher dislocation rate.