Abstract

Joint arthroplasty is a common surgical procedure, with over 185,000 primary hip and knee arthroplasties performed in England, Wales and Northern Ireland in 2014. After total hip or knee arthroplasty, about 1% of patients develop deep prosthetic joint infection (PJI), which usually requires further major operations to clear the infection. Although PJI affects only a small percentage of patients it is one of the most devastating complications associated with this procedure. Research evidence has focussed on clinical effectiveness of revision surgery while there has been less focus on the impact on patients and support needs. Using a systematic review approach, the aim of this study was to assess support needs and evaluate what interventions are routinely offered to support patients undergoing treatment for PJI following hip or knee arthroplasty.

We systematically searched MEDLINE, Embase, Web of Science, PsycINFO, Cinahl, Social Science Citation Index, and The Cochrane Library from 1980 to February 15, 2015 for observational (prospective cohort, nested case-control, case-control, and retrospective cohort) studies, qualitative studies, and clinical trials that report on the support needs and interventions for patients being treated for PJI or other major adverse occurrences following joint arthroplasty. Data were extracted by two independent investigators and consensus reached with involvement of a third.

Of 4,161 potentially relevant citations, we identified one case-control, one prospective cohort and two qualitative studies for inclusion in the synthesis. Patients report that PJI and treatment had a profoundly negative impact affecting physical, emotional, social and economic aspects of their lives. No study evaluated support interventions for PJI or other major adverse occurrences following hip and knee arthroplasty.

The interpretation of study results is limited by variation in study design, outcome measures and the small number of relevant eligible studies. Findings show that patients undergoing treatment for PJI have extensive physical, psychological, social and economic support needs. Our review highlights a lack of evidence about support strategies for patients undergoing treatment for PJI and other adverse occurrences. There is a need to design, implement and evaluate interventions to support these patients.

Around 1% of the 185,000 primary hip and knee arthroplasties performed in the UK are followed by prosthetic joint infection (PJI). Although PJI affects a small percentage of patients, it is one of the most devastating complications associated with this procedure. Treatment usually involves further major surgery which can adversely affect patients' quality of life. Understanding current service provision provides valuable information needed to design and evaluate support interventions for patients. The aim of this survey was to identify usual care pathways and support in UK NHS orthopaedic centres for this population.

The 20 highestvolume UK NHS orthopaedic centresfor hip and knee arthroplasty account for 33–50% of all cases treated for prosthetic joint infection. Infection leads at each centre were invited to participate in a survey about usual care provision and support for PJI. Questions exploredfollow up time-points; use of standard outcome measures; multidisciplinary care plans; supportive in-patient care and care after treatment; and onward referrals. Survey responses were recorded on a standardised proforma. Data were entered into Excel for analysis, then reviewed and coded into categories and frequency statistics to describe categorical data. A descriptive summary was developed based on these categories.

Eleven of the highestvolume orthopaedic centres completed the survey. Follow-up of patients varied greatly across centres; some centres reviewed patients at weekly or 2 week intervals, while all centres saw patients at 6 weeks. Long-term follow-up varied across centres from 3–4 monthsto 12 monthly. Length of follow-up period varied from until the infection had cleared toindefinitely. Follow-up timepoints were only standardised in 4 out of 11 centres. Only 1 centre had a dedicated infection clinic. Advice on who patients should contact if they had concerns included the consultant, community nurse, extended scope practitioner or the ward, while 3 centres told patients to avoid calling their GP. Only half of the centres routinely used standardised outcome measures with patients with PJI. The majority of centres provided standard physiotherapy and occupational therapy (OT) to in-patients while approximately half also offered social support. Only one centre provided dedicated physiotherapy and OT on a separate infection ward. Three centres provided hospital at home or community services to patients in-between operative stages. Only 3 out of 11 centres stated they had specific multidisciplinary care plans in place for patients. Once discharged most patients were provided with physiotherapy, OT and social services if needed. Common barriersto referral included complexities of referring patients outside the hospital catchment area;lack of availability of community services, and shortage of staff including physiotherapists. Delays in rehab and social services could also be problematic.

Findings show wide variation intreatment pathways and support for patients treated for PJI, both as inpatients and in the community. Only one of the 11 centreswho participated had a dedicated infection clinic. Only one centre suggested they individualised their physiotherapy support. A number of barriers exist to referring patients on to other support services after revision surgery.

Purpose: Accurate determination of the flexion-extension axis of the elbow is critical to the successful placement of elbow arthroplasties, articulated external fixators and ligament reconstructions. We expect axis alignment using computer-assisted techniques to improve the outcome of these procedures. For image-based procedures, registration (i.e. the transformation needed to align two sets of points) during surgery is critical for accurate alignment. A surface-based registration technique, employing a hand-held laser scanner, was evaluated against a stand-alone paired-point registration method to determine whether it led to improved alignment of the elbow’s flexion-extension axis.

Methods: Twelve cadaveric distal-humeri were selected for registration. To perform paired-point (TP-PP) registration, key anatomical landmarks (capitellum, trochlear sulcus and distal humeral shaft) were digitized using a tracked-probe (TP) and an electromagnetic tracking device (Flock of Birds, Ascension Tech). Using the geometric centers of these landmarks, TP-PP registration to CT data was performed. Surface registration was achieved using the iterative closest point (ICP) least-squares algorithm and the results were evaluated for two devices; registration employing the tracked-probe (TP-ICP) and registration employing a hand-held laser scanner, HHS-ICP (FastSCAN, Polhemus). For surface registration, to be consistent with the amount of the joint exposed during a typical surgical procedure, only the articular surface was used for alignment.

Results: Registration error (Figure 1) was lowest for the HHS-ICP method with a mean of 0.8±0.3-mm (maximum error, 1.4-mm) in translation, compared with a mean error of 1.5±0.5-mm (maximum error, 2.4-mm) for the TP-ICP method and 1.9±1.0-mm (maximum error, 4.4-mm) for the TP-PP method (p< 0.001). Errors in TP-PP registration were greatest in the coronal plane while TP-ICP registration often resulted in an error along the transverse plane (Figure 2).

Conclusions: Overall, the reliability of surface-based registration combined with the implementation of the hand-held laser scanner demonstrated greater registration accuracy. A reliable surface-based registration technique may lead to a more accurate determination of the elbow’s flexion-extension axis during surgical procedures, leading to improved joint motion and implant longevity. The implications of these results can also be extended to other joints that employ comparable computer-assisted surgical techniques.