Introduction

There is current debate concerning the most biomechanically advantageous knee implant systems, and there is also currently great interest in improving patient satisfaction after knee arthroplasty. Additionally, there is no consensus whether a posterior-stabilized (PS) total knee device is superior to a more congruent, cruciate-substituting, medially-stabilized device (MS). This study compared the clinical outcomes of two such devices. The primary hypothesis was that the clinical outcomes, and specifically the patient satisfaction as measured by the Forgotten Joint Score, would be better in the MS group.

Introduction

Mid-flexion stability is believed to be an important factor influencing successful clinical outcomes in total knee arthroplasty. The post of a posterior-stabilizing (PS) knee engages the cam in >60° of flexion, allowing for the possibility of paradoxical mid-flexion instability in less than 60° of flexion. Highly-conforming polyethylene insert designs were introduced as an alternative to PS knees. The cruciate-substituting (CS) knee was designed to provide anteroposterior stability throughout the full range of motion.

At our district general hospital in the southwest of England, around 694 total knee replacements (TKR) are performed annually. Since spring 2013 we have been using an enhanced recovery protocol for all TKR patients, yet we have neither assessed compliance with the protocol nor whether its implementation has made a discernible and measurable difference to the delivery of care in this patient population. Enhanced recovery after surgery (ERAS) protocols are multi-modal care pathways designed to aid recovery. They are based on best evidence and promote a multi-disciplinary approach which standardises care and encompasses nutrition, analgesia and early mobilisation throughout the pre, intra and postoperative phases of an inpatient stay. ERAS has been found to reduce length of stay (LOS), readmission rates and analgesic requirements following surgery.^{1, 2, 3} Additionally, they have been shown to improve range of knee movement following TKR and improve mobility, patient satisfaction whilst reducing mortality and morbidity.^{4, 5, 6} With these benefits in mind, we sought to investigate how well our trauma and orthopaedic department was complying with a local ERAS protocol and whether we could replicate the benefits seen within the literature.

Following approval from our local audit office in September 2015 we generated a patient list of elective TKR patients under the same surgeon before and after the implementation of the ERAS protocol. Using discharge summaries and patient notes we extracted data for 39 patients operated on prior to the ERAS implementation between January 2011 and December 2012 and 27 patients following its introduction between January 2014 and September 2015. Data collected included length of stay, time to discharge from inpatient physiotherapy and use of analgesia and antiemetics. Alongside this we audited the compliance with all facets of the local ERAS protocol.

There was no statistically significant difference between the 2 groups in terms of demographics or pre-operative morbidity. Overall compliance with the ERAS protocol was good but there was some variability, especially with intraoperative medication and type of anaesthesia which was likely due to individual patient factors. Compliance with postoperative analgesia was especially good with 93% of patients receiving all 4 suggested analgesics within the ERAS group. Length of stay (LOS) was significantly reduced by 0.5 days per patient (p value < 0.4).

Overall compliance with the ERAS protocol was good but there was some variability, especially with intraoperative medication and type of anaesthesia, which was likely due to individual patient factors. Compliance with postoperative analgesia was especially good with 93% of patients receiving all suggested analgesics within the ERAS group. In terms of LOS, we found a statistically significant difference between the pre-ERAS and ERAS group of 0.5 days per patient. Within the context of our DGH, a 0.5 day reduction in LOS translates to around 350 bed days per year and a potential saving of GBP 105,000 (EUR 132,000) making this a clinically significant finding.

Introduction:

There is no consensus whether a traditional post and cam-style posterior stabilized (PS) total knee device is superior to a deep-dish, more congruent cruciate-substituting (CS) device. This study compared the clinical and radiographic outcomes of two such devices. The primary hypothesis was that the clinical outcomes would be equivalent and the secondary hypothesis was that there would be measurable differences in the tourniquet time and intraoperative blood loss.

Introduction:

Significant proximal femoral remodeling occurs after total hip arthroplasty (THA), with regions of bone loss, and regions of hypertrophy. This study compared three implants for changes in femoral bone mineral density over 2 years following primary uncemented hip arthroplasty with a conventional stem (THA), a novel femoral neck-sparing short hip stem (NS-THA), and resurfacing hip arthroplasty (RHA).

Introduction and Aims: This study evaluated the proximal femoral remodelling associated with three uncemented femoral prostheses of different designs and surface treatments. We hypothesised that less bone loss will occur over time with a titanium implant designed for proximal stress transfer compared to a more rigid stem that produces diaphyseal loading.

Method: During total hip arthroplasty (THA), patients were implanted with either: AML cobalt-chrome alloy porous-coated stem (11 patients), Osteonics titanium alloy hydroxyapatite-coated stem (13 patients), or Sulzer titanium alloy hydroxyapatite-coated stem (eight patients). All patients followed the same surgical and post-surgical protocol for THA. Dual energy x-ray absorptiometry (DEXA) scans of the operated proximal femur were performed on all patients pre-operatively, three to seven days post-operatively, and then six weeks, six months, and annually up to five years post-operatively. Longitudinal changes in bone mineral density (BMD) were compared within and between the two groups.

Results: Using the first post-op DEXA scan as baseline, the percent change in BMD (g/cm²) at one year was −17.06% in patients implanted with the AML stem. The percent change in BMD at one year was −3.06% in the Osteonics group and in the Sulzer group, the percent change in BMD at one year was −4.11%. The greater bone loss observed with the AML stem was found to be statistically different than the bone loss observed with the other two stems. These findings continued at three and five years post-operatively.

Conclusion: There was a trend toward less bone atrophy and preservation of bone stock in patients implanted with both the HA and Sulzer stems. Extensively coated, diaphyseal-fitting, CoCr stems (AML) definitely caused greater bone loss, both proximally and in the diaphysis.

Introduction and Aims: This study evaluates the effect of risedronate (Actonel) on proximal femoral bone loss after total hip arthroplasty (THA). Studies have shown that alendronate (Fosamax) reduces periprosthetic bone loss after primary THA. We hypothesise that patients who take risedronate, post-THA, will have less bone loss than patients not taking risedronate.

Method: All patients in this prospective study undergo uncemented THA and follow the same post-operative protocol. Patients in the study group take five mg of risedronate daily, beginning five to seven days pre-operatively, and continuing for 24 months after surgery. Patients randomised to the control group do not receive risedronate. Dual energy x-ray absorptiometry (DEXA) scans of the operated proximal femur are performed on all patients pre-operatively, three to seven days post-operatively, and then six weeks, six months, one year and two years post-operatively. Longitudinal changes in bone mineral density (BMD) are compared within and between the two groups.

Results: Analysis of data for female subjects showed the percent change in BMD (g/cm²) for the control group at six months was −9.71% and for the study group −4.55%. Longitudinal changes in BMD between groups were examined using repeated measures analysis within each gender and were found to be significantly different between groups of females (p=.05). A similar trend was observed among the male subjects. One and two-year prospective data will be presented at the meeting.

Conclusion: Bone loss after THA can increase the rate of failure of THA and cause revision surgery to be more complex and have compromised outcomes. Short-term data reveal significantly decreased bone loss after uncemented THA among patients taking risedronate.

1. A lateral intermuscular approach to the hip joint is described for replacement of the head of the femur by a prosthesis.

2. Advantages claimed for it are that it is attended by little or no shock, because the operation is rapid and relatively bloodless; that adequate exposure can be gained without dividing muscle or tendon; and that muscle function is unimpaired and so walking can be allowed early. The exposure is easily extended if unexpected difficulty is encountered.

3. Prosthetic replacement of the femoral head through this incision is advocated as a primary measure for elderly or unfit patients with fractured femoral neck.