Abstract

Cementless stem designs in total hip arthroplasty differ in relation to geometry and area of fixation. We utilised radiostereometric analysis (RSA) to evaluate the 2-year migration of a novel, short, proximally coated femoral stem.

30 participants undergoing primary total hip replacement for any cause (rheumatoid or inflammatory arthritis, osteoarthritis) were prospectively recruited in this study. Osteoporotic patients and cases of suspected infection were excluded. All patients received a short blade stem, proximally coated with a reduced lateral shoulder and narrow triple taper geometry to minimise bone removal. RSA radiographs were performed post-operatively and at 6 weeks, 6 months, 1- and 2 years. The Harris Hip Score (HHS), Oxford Hip Score (OHS) and EQ-5D were collected at baseline and at 2 years post-operatively. The stability of implants and complications were captured during each follow-up visit.

A total of 14 female and 16 male patients were recruited with a mean age of 64.8 (range 47 to 75). At two years the mean subsidence of the stem was 0.34 mm (SD 0.62) and the total migration 0.74 mm (SD 0.60). The mean medial translation at two years was 0.059 (0.24) and the mean anterior translation 0.12 (0.59) respectively. Baseline PROM scores improved significantly at 2-years from pre-operatively (median and interquartile range): HHS from 33 (18.25) to 92 (19), EQ5D from 0.5 (0.35) to 0.94 (0.17), OHS from 21 (18.25) to 42 (4.25). P-value for all comparisons was <0.001. 2-year follow up data revealed no complications. There were no stem revisions in study participants and no heterotopic ossifications were identified on radiographs.

2-year migration results of a cementless, short blade, proximally coated tapered femoral stem using RSA, showed the stem exhibits a predictable migration pattern and achieves initial stability. This is highly likely to translate to mid and long-term stability, which needs to be corroborated by long-term outcome studies. Furthermore, participants demonstrated excellent clinical, patient reported and radiological outcomes after 2 years of follow up to support expansion in the use of this prosthesis.

MOXIMED KineSpring® Knee Implant System is an Orthopaedic device designed for younger or highly active patients with osteoarthritis. The device is placed under the skin, is attached to the tibia and femur, and contains springs which help limit some of the forces that are transmitted through the knee during activities such as walking or running and thereby relieve pain that may be experienced by patients with early arthritis of the knee. The aim of this study is to determine the long term safety and efficacy of the KineSpring knee implant system.

This is a prospective case series involving two centres in Glasgow. 29 patients (mean age of 45.1 years and range 18-65 years) were recruited into the study between 2011 and 2016. The Primary outcome measure was Oxford knee score (OKS) at 2, 5 and 10 years post-operatively. Secondary outcome measures include device related complications and survival, patient reported functional outcome measures, patient satisfaction, pain levels and change in radiographic classification of osteoarthritis

At 2-year follow-up, 7 implants were removed (74.1% survival). Complications include deep infection, requiring removal in 1 patient, 2 implant failures requiring removal and one spring breakage. In comparison to pre-operative measures there was an improvement in the pain (3.58 vs. 5.20, p=0.02), stiffness (4.16 vs. 4.47, p=0.6) and OKS (32.4 vs. 36.9, p=0.03).

The KineSpring improves overall pain, stiffness and functional outcome at 2 years following surgery, however there was a high rate of removal and further long-term follow up analysis is required regarding its effectiveness.

Objective

Mortality rates reported by the National Joint Registry for England and Wales (NJR) were higher following cemented total knee replacement (TKR) compared with uncemented procedures. The aim of this study is to examine and compare the effects of cemented and uncemented TKR on the activation of selected markers of inflammation, endothelium, and coagulation, and on the activation of selected cytokines involved in the various aspects of the systemic response following surgery.

We report the survival, functional and radiological outcome of a series of Birmingham hip resurfacing procedures performed by a single surgeon at a district general hospital. The aim of this study was to retrospectively report the medium term outcome and survival of our patients.

There were 45 hip resurfacings performed in 38 patients between 2004 and 2010. Patients were followed for a mean duration of four years. Mean age of 52.6 years (range 26 to 65). Although no patients were lost to follow up, four did not complete the oxford hip scoring assessment.

The median Oxford hip score was 16.25 points (range 12–39 points, standard deviation 5.9) at 48 months follow up (range 11.5–84.2 months). The mean acetabular inclination was 46.9 (range 40.9–59.9) in the 45 hip resurfacings post operatively.

There was one patient with varus subsidence of the prosthesis and one patient with persistent hip pain post operatively under investigation currently. There was no definite radiological evidence of loosening or of narrowing of the femoral neck. No cases were revised and no cases developed any other complications.

These medium-term results from a district general hospital are comparable to the other studies performed. Few independent studies have reported the outcome of resurfacing arthroplasty of the hip in a district general hospital. Further evaluation and follow up of these patients is required to address the concerns raised by other centers related to fracture and metal debris.

Rivaroxaban has been recommended for routine use as a thromboprophylactic agent in patients undergoing lower-limb arthroplasty. Starting January 2011, our unit has converted from aspirin to Rivaroxaban use routinely following lower-limb arthroplasty for venous thromboembolism (VTE) prophylaxis. The aim of this audit was to retrospectively review its efficacy and the morbidity associated with its use.

All patients undergoing primary and revision lower-limb arthroplasty between February 2011 and July 2011 were reviewed. All patients undergoing total knee replacement surgery and total hip replacement surgery received oral rivaroxaban 10 mg daily post-operatively for 14 days and 35 days respectively. Outcome measures recorded were; investigation for DVT/PE, rate of DVT/PE, wound complications (infection, dehiscence, leaking, bleeding), blood transfusion rate and readmission rate within 6 weeks of surgery.

Of the 162 patients identified, 19 were excluded due to insufficient information or because they did not receive rivaroxaban as VTE prophylaxis. 141 patients (mean age 71.7 years) were included. 69 primary and 5 revision total knee replacements were performed. 60 primary and 7 revision total hip replacements were performed. 9 patients (6.4%) underwent Doppler USS for a painful swollen leg with 1 (0.7%) DVT diagnosed. None were investigated for a pulmonary embolus. 25 (17.7%) patients developed wound complications: 10 superficial infections requiring oral antibiotics, 2 deep infections requiring theatre washout, 1 wound dehiscence, 5 continuously leaking wounds, 5 bleeding wounds/haematomas. 26 (18.4%) patients required post-operative blood transfusion (average 2.2 units). 12 (8.5%) patients were re-admitted within 6 weeks with post-op complications (6 wound complications, 5 painful/swollen limbs, 1 large per-vaginal bleed).

In keeping with previous literature, the rate of VTE following lower-limb arthroplasty using rivaroxaban as prophylaxis is low. However, the rate of morbidity was higher when compared with the use of aspirin in our centre between April and September 2010.