Empiric antibiotic treatment for periprosthetic joint infections: a national survey in The Netherlands.

Early periprosthetic joint infection (PJI) is generally treated by means of debridement, antibiotics and implant retention (DAIR). Subsequently, empiric antibiotic therapy is commenced directly after surgery which is important for the successful treatment of PJI. The aim of this study is to evaluate current nationwide empiric antibiotic treatment regimens for PJI in the Netherlands. An electronic 15-question survey addressing the empiric antibiotic treatment strategy for PJI following THA or TKA was sent to orthopaedic surgeons in all Dutch hospitals in April 2019. Orthopaedic surgeons active in every single Dutch orthopaedic hospital (n=69) were approached. At least one surgeon in every hospital completed the survey (100% response rate). A protocol dictating the empiric antibiotic treatment following DAIR was used in 87% (60 hospitals). Among all hospitals, 72% (50 hospitals) used antibiotic monotherapy and 28% (19 hospitals) used combination therapy. Cefazolin was the most commonly used regimen in centres opting for monotherapy (42%, 29 hospitals). Similar regimens were used for the empiric treatment of suspected early PJI after revision surgery and for acute hematogenous PJI. In septic patients, combination therapy was preferred (64%). 81% (56 hospitals) incubated tissue biopsies for a minimum of 10 days whereas 16% (9 hospitals) indicated an incubation period of 7 days or less. Even in a small country such as the Netherlands there seems to be no uniformity regarding empiric antibiotic treatment for PJI. Increased uniformity regarding empiric treatment could be an important first step in improving PJI treatment.

Complications and survival of conversion to total hip arthroplasty after failed primary osteosynthesis compared to primary total hip arthroplasty in femoral neck fractures.

INTRODUCTION: Surgical treatment options for patients with an intracapsular fracture of the femoral neck (FFN) are primary osteosynthesis as a femoral head-spearing technique or primary (hemi)arthroplasty. The most common complications after primary osteosynthesis, such as avascular necrosis (AVN) or non-union, can result in conversion to Total Hip Arthroplasty (cTHA). Data concerning complications and survival rates of cTHA in comparison to primary Total Hip Arthroplasty (pTHA) after FFN are limited due to the absence of well-designed studies. METHODS: A multicentre retrospective cohort study was conducted in three Dutch hospitals comparing the rate of postoperative dislocations, periprosthetic fractures, prosthetic joint infections, blood loss during surgery (>1000 mL), postoperative cardiac- and pulmonary complications after pTHA and cTHA in the first year after surgery. As a secondary outcome implant survival of pTHA and cTHA in terms of revision rates was evaluated. RESULTS: In total 548 patients were included (pTHA n = 264 and cTHA n = 284) with a mean follow-up of 5 years (±3.5 SD). No significant differences were found in postoperative complications rates. The revision rate in the pTHA group was 7.2% in comparison to 7.7% in the cTHA group (p = 0.81). No difference in the short-term implant survival was found between both groups (p = 0.81). CONCLUSION: This study showed no significant differences in terms of postoperative complication rates in the first year after pTHA and cTHA in patients with FFN. Also, no significant difference in short-term implant survival of primary and conversion total hip arthroplasty was found.

Long-term (> 10 years) clinical outcomes of instrumented posterolateral fusion for spondylolisthesis.

PURPOSE: Despite the rapid increase in instrumented spinal fusions for a variety of indications, most studies focus on short-term fusion rates. Long-term clinical outcomes are still scarce and inconclusive. This study investigated clinical outcomes > 10 years after single-level instrumented posterolateral spinal fusion for lumbar degenerative or isthmic spondylolisthesis with neurological symptoms. METHODS: Cross-sectional long-term follow-up among the Dutch participants of an international multicenter randomized controlled trial comparing osteogenic protein-1 with autograft. Clinical outcomes were assessed using the Oswestry Disability Index (ODI), EQ-5D-3L and visual analogue scale (VAS) for leg and back pain, as well as questions on satisfaction with treatment and additional surgery. RESULTS: The follow-up rate was 73% (41 patients). At mean 11.8 (range 10.1-13.7) years after surgery, a non-significant deterioration of clinical outcomes compared to 1-year follow-up was observed. The mean ODI was 20 ± 19, mean EQ-5D-3L index score 0.784 ± 0.251 and mean VAS for leg and back pain, respectively, 34 ± 33 and 31 ± 28. Multiple regression showed that diagnosis (degenerative vs. isthmic spondylolisthesis), graft type (OP-1 vs. autograft) and 1-year fusion status (fusion vs. no fusion) were not predictive for the ODI at long-term follow-up (p = 0.389). Satisfaction with treatment was excellent and over 70% of the patients reported lasting improvement in back and/or leg pain. No revision surgeries for non-union were reported. CONCLUSION: This study showed favourable clinical outcomes > 10 years after instrumented posterolateral spinal fusion and supports spondylolisthesis with neurological symptoms as indication for fusion surgery.

Low conversion rates toward total hip arthroplasty after hemiarthroplasty in patients under 75 years of age.

INTRODUCTION: An intracapsular fracture of the femoral neck is frequent in the elderly. Patients can be treated with either total hip arthroplasty or hemiarthroplasty. There is a continuous discussion about the treatment in elderly patients who are still healthy, active and mentally untroubled. A potential consequence of hemiarthroplasty, especially in the relatively young elderly, could be conversion to total hip arthroplasty. The conversion rate must be acceptable, and clinical outcome must be sufficient to justify the treatment with hemiarthroplasty in this group of patients. This study evaluates the conversion rate of hemiarthroplasty to total hip arthroplasty and clinical outcome in patients under 75 years of age. METHODS: This study identified 248 patients, younger than 75 years at time of operation, with a fracture of the femoral neck treated with hemiarthroplasty. Patient-reported outcome measurements (VAS pain during rest and activity and WOMAC) were assessed by telephone interviews. Furthermore, radiographic evaluation for the presence of acetabular wear was performed. RESULTS: At a follow-up of 5.1 (0.9-9.6) years, the conversion rate was 7.3%. Mean VAS pain in rest was 0.89 (0-10), the mean VAS pain during activity was 2.2 (0-10), and the WOMAC showed a mean of 16.51 (0-64). At time of follow-up, 38.7% of patients had died. Radiographic evaluation of the unrevised group showed in one patient signs of acetabulum wear. CONCLUSION: Hemiarthroplasty in the relatively young elderly after a fracture of the femoral neck demonstrates an acceptable conversion rate. Furthermore, unrevised patients show low complaints of pain. To prevent one conversion to total hip arthroplasty, 13.7 patients should be treated with total hip arthroplasty that will not undergo a conversion at a later stage. Therefore, hemiarthroplasty remains a viable treatment of femoral neck fractures in relatively young patients. There seems to be no space for standardized decision making concerning the choice of treatment. An individual approach is required.

No decline in high patient satisfaction after total hip arthroplasty at long-term follow-up.

INTRODUCTION: Patient satisfaction is gaining popularity as an important outcome parameter in today's healthcare system and in particular in evaluating the outcome of joint arthroplasty. Total hip arthroplasty (THA) is a very successful procedure with reports on high patient satisfaction at short-term follow-up. Commonly used clinical outcome parameters remain good at long-term follow-up; however, whether this also accounts for patient satisfaction remains unclear. This study presents a prospective follow-up of patient satisfaction after THA, and a possible correlation with common outcome parameters was established. METHODS: This study entails a concise follow-up of an earlier study on patient satisfaction 2.5 years after THA. Patient satisfaction was repeatedly measured with a visual analogue scale (VAS) after a mean follow-up of 13.5 (12.6-14.2) years in a prospective cohort of 147 patients (153 THAs). In addition, VAS pain and common clinical outcome parameters (WOMAC, OHS and SF-36) were also reassessed and were compared with short-term results after a mean follow-up of 2.5 (1.3-3.0) years. RESULTS: At a follow-up of 13.5 (12.6-14.2) years, the median VAS for satisfaction was 95 (26-100) compared to a median VAS satisfaction of 98 (0-100) at earlier follow-up (p = 0.781). Overall, the clinical outcome parameters also remained good at long-term follow-up without significant changes. However, a rather low correlation with VAS satisfaction was encountered. Pain during activity showed the highest correlation (- 0.686) with VAS satisfaction. CONCLUSION: Patient satisfaction after THA remains high after prolonged follow-up. Apparently patients do not get used to the successful results of their THA. A rather low correlation with common clinical outcome parameters suggests that patient satisfaction is a separate entity. Since patient satisfaction correlated best with pain during activity, this is probably the most important aspect in patient satisfaction. Measurement of patient satisfaction has additional value and may even replace some of the more commonly used questionnaires.

Similar incidence of periprosthetic fluid collections after ceramic-on-polyethylene total hip arthroplasties and metal-on-metal resurfacing arthroplasties: results of a screening metal artefact reduction sequence-MRI study.

Patients from a randomised trial on resurfacing hip arthroplasty (RHA) (n = 36, 19 males; median age 57 years, 24 to 65) comparing a conventional 28 mm metal-on-metal total hip arthroplasty (MoM THA) (n = 28, 17 males; median age 59 years, 37 to 65) and a matched control group of asymptomatic patients with a 32 mm ceramic-on-polyethylene (CoP) THA (n = 33, 18 males; median age 63 years, 38 to 71) were cross-sectionally screened with metal artefact reducing sequence-MRI (MARS-MRI) for pseudotumour formation at a median of 55 months (23 to 72) post-operatively. MRIs were scored by consensus according to three different classification systems for pseudotumour formation. Clinical scores were available for all patients and metal ion levels for MoM bearing patients. Periprosthetic lesions with a median volume of 16 mL (1.5 to 35.9) were diagnosed in six patients in the RHA group (17%), one in the MoM THA group (4%) and six in the CoP group (18%). The classification systems revealed no clear differences between the groups. Solid lesions (n = 3) were exclusively encountered in the RHA group. Two patients in the RHA group and one in the MoM THA group underwent a revision for pseudotumour formation. There was no statistically significant relationship between clinical scoring, metal ion levels and periprosthetic lesions in any of the groups. Periprosthetic fluid collections are seen on MARS-MRI after conventional CoP THA and RHA and may reflect a soft-tissue collection or effusion. Currently available MRI classification systems seem to score these collections as pseudotumours, causing an-overestimatation of the incidence of pseudotumours.

Metal ion levels in patients with a lumbar metal-on-metal total disc replacement: should we be concerned?

The purpose of this study was to evaluate whether concerns about the release of metal ions in metal-on-metal total hip replacements (THR) should be extended to patients with metal-bearing total disc replacements (TDR). Cobalt and chromium levels in whole blood and serum were measured in ten patients with a single-level TDR after a mean follow-up of 34.5 months (13 to 61) using inductively-coupled plasma mass spectrometry. These metal ion levels were compared with pre-operative control levels in 81 patients and with metal ion levels 12 months after metal-on-metal THR (n = 21) and resurfacing hip replacement (n = 36). Flexion-extension radiographs were used to verify movement of the TDR. Cobalt levels in whole blood and serum were significantly lower in the TDR group than in either the THR (p = 0.007) or the resurfacing group (p < 0.001). Both chromium levels were also significantly lower after TDR versus hip resurfacing (p < 0.001), whereas compared with THR this difference was only significant for serum levels (p = 0.008). All metal ion levels in the THR and resurfacing groups were significantly higher than in the control group (p < 0.001). In the TDR group only cobalt in whole blood appeared to be significantly higher (p < 0.001). The median range of movement of the TDR was 15.5° (10° to 22°). These results suggest that there is minimal cause for concern about high metal ion concentrations after TDR, as the levels appear to be only moderately elevated. However, spinal surgeons using a metal-on-metal TDR should still be aware of concerns expressed in the hip replacement literature about toxicity from elevated metal ion levels, and inform their patients appropriately.

Changes in bone mineral density in the proximal femur after hip resurfacing and uncemented total hip replacement: A prospective randomised controlled study.

We undertook a randomised prospective follow-up study of changes in peri-prosthetic bone mineral density (BMD) after hip resurfacing and compared them with the results after total hip replacement. A total of 59 patients were allocated to receive a hip resurfacing (n = 29) or an uncemented distally fixed total hip replacement (n = 30). The BMD was prospectively determined in four separate regions of interest of the femoral neck and in the calcar region corresponding to Gruen zone 7 for the hip resurfacing group and compared only to the calcar region in the total hip replacement group. Standardised measurements were performed pre-operatively and after three, six and 12 months. The groups were well matched in terms of gender distribution and mean age. The mean BMD in the calcar region increased after one year to 105.2% of baseline levels in the resurfaced group compared with a significant decrease to 82.1% in the total hip replacement group (p < 0.001) by 12 months. For the resurfaced group, there was a decrease in bone density in all four regions of the femoral neck at three months which did not reach statistical significance and was followed by recovery to baseline levels after 12 months. Hip resurfacing did indeed preserve BMD in the inferior femoral neck. In contrast, a decrease in the mean BMD in Gruen zone 7 followed uncemented distally fixed total hip replacement. Long term follow-up studies are necessary to see whether this benefit in preservation of BMD will be clinically relevant at future revision surgery.

A prospective, randomized, controlled, multicenter study of osteogenic protein-1 in instrumented posterolateral fusions: report on safety and feasibility.

STUDY DESIGN: A prospective, randomized, controlled, multicenter clinical study. OBJECTIVE: To evaluate the safety and feasibility of osteogenic protein (OP)-1 in 1-level lumbar spine instrumented posterolateral fusions. SUMMARY OF BACKGROUND DATA: Instrumented posterolateral fusion with the use of autograft is a commonly performed procedure for a variety of spinal disorders. However, harvesting of bone from the iliac crest is associated with complications. A promising alternative for autograft are bone morphogenetic proteins. METHODS: As part of a larger prospective, randomized, multicenter study, 36 patients were included, who received a 1-level instrumented posterolateral fusion of the lumbar spine. All patients had a degenerative or isthmic spondylolisthesis with symptoms of neurologic compression. There were 2 treatment arms: OP-1 combined with locally available bone from laminectomy (OP-1 group) or iliac crest autograft (autograft group). The primary outcome was the fusion rate based on a computed tomography scan after 1-year follow-up. The clinical outcome was measured using the Oswestry Disability Index. Additionally, the safety of OP-1 was evaluated by comparing the number and severity of adverse events that occurred between both groups. RESULTS: Using strict criteria, fusion rates of 63% were found in the OP-1 group and 67% in the control group (P = 0.95). There was a decrease in Oswestry scores at subsequent postoperative time points compared with preoperative values (P > 0.001). There were no significant differences in the mean Oswestry scores between the study group and control group at any time point (P = 0.56). No product-related adverse events occurred. CONCLUSION: The results demonstrate that OP-1 combined with locally obtained autograft is a safe and effective alternative for iliac crest autograft in instrumented single-level posterolateral fusions of the lumbar spine. The main advantage of OP-1 is that it avoids morbidity associated with the harvesting of autogenous bone grafts from the iliac crest.

Partial versus unrestricted weight bearing after an uncemented femoral stem in total hip arthroplasty: recommendation of a concise rehabilitation protocol from a systematic review of the literature.

The aim of this systematic review was to find evidence-based support in the literature to allow immediate unrestricted weight bearing after primary uncemented total hip arthroplasty (THA). Accelerated rehabilitation programs for THA are becoming increasingly popular to shorten hospital stay and to facilitate rapid restoration of function. The goals of these rehabilitation programs could be more easily achieved if immediate unrestricted weight bearing (UWB) could be allowed after a THA. So far, however, immediate weight bearing is frequently contraindicated in widely accepted protocols for uncemented THA due to fear for subsidence and absence of osseous integration of the femoral stem. Thus, frequently protected weight bearing and restricted activities are still advocated for at least 6 weeks after surgery. In addition, we analyzed the literature to come to a recommendation on gait pattern and walking aid. From a systematic search in several electronic databases 13 studies met the inclusion criteria. These studies were reviewed according to the Cochrane methodology. We found moderate to strong evidence that no adverse effects on subsidence and osseous integration of the femoral stem after uncemented THA occur after immediate UWB. Based on this literature review, we recommend early rehabilitation after uncemented THA with a reciprocally gait pattern using crutches, one cane for independency in ADL in case patients walk limp-free and walking without crutches as soon as possible. During the first weeks after surgery only stair climbing should be performed with protected weight bearing because of high torsion loads on the hip.

Crosslinked type II collagen matrices: preparation, characterization, and potential for cartilage engineering.

The limited intrinsic repair capacity of articular cartilage has stimulated continuing efforts to develop tissue engineered analogues. Matrices composed of type II collagen and chondroitin sulfate (CS), the major constituents of hyaline cartilage, may create an appropriate environment for the generation of cartilage-like tissue. In this study, we prepared, characterized, and evaluated type 11 collagen matrices with and without CS. Type II collagen matrices were prepared using purified, pepsin-treated, type II collagen. Techniques applied to prepare type I collagen matrices were found unsuitable for type II collagen. Crosslinking of collagen and covalent attachment of CS was performed using 1-ethyl-3-(3-dimethyl aminopropyl)carbodiimide. Porous matrices were prepared by freezing and lyophilization, and their physico-chemical characteristics (degree of crosslinking, denaturing temperature, collagenase-resistance, amount of CS incorporated) established. Matrices were evaluated for their capacity to sustain chondrocyte proliferation and differentiation in vitro. After 7 d of culture, chondrocytes were mainly located at the periphery of the matrices. In contrast to type I collagen, type II collagen supported the distribution of cells throughout the matrix. After 14 d of culture, matrices were surfaced with a cartilagenous-like layer, and occasionally clusters of chondrocytes were present inside the matrix. Chondrocytes proliferated and differentiated as indicated by biochemical analyses, ultrastructural observations, and reverse transcriptase PCR for collagen types I, II and X. No major differences were observed with respect to the presence or absence of CS in the matrices.