Martin Clauss

Influence of leg length discrepancy on clinical results after total hip arthroplasty - A prospective clinical trial

The effect of leg length differences on early clinical outcome after total hip arthroplasty remains uncertain. We performed a prospective study on 94 patients who were evaluated preoperatively and one year after surgery for clinical leg length differences, which were then compared with radiological measurements. The effect of leg length differences on walking ability, limp, pain and patient satisfaction was studied. The mean clinical leg length difference after operation was 0.05 cm (–1.5 to 1.5, SD 0.5). Clinical and radiological measurements correlated poorly (ω=0.36 pre- and ω=0.186 postoperatively). Patients with a shorter operated leg on clinical assessment were more prone to limping (p<0.05), and patients with a longer leg had more pain compared to patients with equal leg lengths (p<0.05). Walking ability, Harris Hip Score and patient satisfaction were only marginally affected by leg length differences. Virtually equal leg length was achieved for most patients but small differences had a negative influence in relation to limping and pain. Patients should be counselled pre-operatively about possible leg length differences and associated symptoms.

Isothermal microcalorimetry: a novel method for real‐time determination of antifungal susceptibility of Aspergillus species

We evaluated microcalorimetry for real-time susceptibility testing of Aspergillus spp. based on growth-related heat production. The minimal heat inhibitory concentration (MHIC) for A. fumigatus ATCC 204305 was 1 mg/L for amphotericin B, 0.25 mg/L for voriconazole, 0.06 mg/L for posaconazole, 0.125 mg/L for caspofungin and 0.03 mg/L for anidulafungin. Agreement within two 2-fold dilutions between MHIC (determined by microcalorimetry) and MIC or MEC (determined by CLSI M38A) was 90% for amphotericin B, 100% for voriconazole, 90% for posaconazole and 70% for caspofungin. This proof-of-concept study demonstrated the potential of isothermal microcalorimetry for growth evaluation of Aspergillus spp. and real-time antifungal susceptibility testing.

High bacterial load in negative pressure wound therapy (NPWT) foams used in the treatment of chronic wounds

No earlier study has investigated the microbiology of negative pressure wound therapy (NPWT) foam using a standardized manner. The purpose of this study is to investigate the bacterial load and microbiological dynamics in NPWT foam removed from chronic wounds (>3 months). To determine the bacterial load, a standardized size of the removed NPWT foam was sonicated. The resulting sonication fluid was cultured, and the colony‐forming units (CFU) of each species were enumerated. Sixty‐eight foams from 17 patients (mean age 63 years, 71% males) were investigated. In 65 (97%) foams, ≥ 1 and in 37 (54%) ≥2 bacterial types were found. The bacterial load remained high during NPWT treatment, ranging from 104 to 106 CFU/ml. In three patients (27%), additional type of bacteria was found in subsequent foam cultures. The mean bacterial count ± standard deviation was higher in polyvinyl alcohol foam (6.1 ± 0.5 CFU/ml) than in polyurethane (5.5 ± 0.8 CFU/ml) (p = 0.02). The mean of log of sum of CFU/ml in foam from 125 mmHg (5.5 ± 0.8) was lower than in foam from 100 mmHg pressure (5.9 ± 0.5) (p = 0.01). Concluding, bacterial load remains high in NPWT foam, and routine changing does not reduce the load.

Standard transgluteal versus minimal invasive anterior approach in hip arthroplasty: a prospective, consecutive cohort study

A minimally invasive anterior approach (MIS) was compared to a standard lateral approach in primary total hip arthroplasty. Clinical and radiological outcomes were analyzed 6 weeks, 12 weeks, one year and two years after surgery. The duration of surgery was longer, mobility one week after surgery was better and time of hospitalization was shorter for minimally invasive-treated patients. They had less pain during movement, limping, better Harris Hip Score and satisfaction after 6 weeks, which remained after 12 weeks and 1 year, but not after two years. There were two deep infections in the MIS group. Radiological results were not affected. The infections might be a point of concern, but there were no other disadvantages of the MIS approach. In fact, early rehabilitation was facilitated and clinical results were improved. Our results encourage the continuous use of the MIS anterior approach instead of the lateral approach.

Fixation and loosening of the cemented Müller straight stem: A LONG-TERM CLINICAL AND RADIOLOGICAL REVIEW

The original forged Müller straight stem (CoNiCr) has shown excellent ten- to 15-year results. We undertook a long-term survival analysis with special emphasis on radiological changes within a 20-year period of follow-up. In all, 165 primary total hip replacements, undertaken between July 1984 and June 1987 were followed prospectively. Clinical follow-up included a standardised clinical examination, and radiological assessment was based on a standardised anteroposterior radiograph of the pelvis, which was studied for the presence of osteolysis, debonding and cortical atrophy. Survival of the stem with revision for any reason was 81% (95% confidence interval (CI), 76 to 86) at 20 years and for aseptic loosening 87% (95% CI, 82 to 90). At the 20-year follow-up, 15 of the surviving 36 stems showed no radiological changes. Debonding (p = 0.005), osteolysis (p = 0.003) and linear polyethylene wear (p = 0.016) were associated with aseptic loosening, whereas cortical atrophy was not associated with failure (p = 0.008). The 20-year results of the Müller straight stem are comparable to those of other successful cemented systems with similar follow-up. Radiological changes are frequently observed, but with a low incidence of progression, and rarely result in revision. Cortical atrophy appears to be an effect of ageing and not a sign of loosening of the femoral component.

Debridement and implant retention in the management of hip periprosthetic joint infection: outcomes following guided and rapid treatment at a single centre

Aims To analyse the effectiveness of debridement and implant retention (DAIR) in patients with hip periprosthetic joint infection (PJI) and the relationship to patient characteristics. The outcome was evaluated in hips with confirmed PJI and a follow‐up of not less than two years. Patients and Methods Patients in whom DAIR was performed were identified from our hip arthroplasty register (between 2004 and 2013). Adherence to criteria for DAIR was assessed according to a previously published algorithm. Results DAIR was performed as part of a curative procedure in 46 hips in 42 patients. The mean age was 73.2 years (44.6 to 87.7), including 20 women and 22 men. In 34 hips in 32 patients (73.9%), PJI was confirmed. In 12 hips, the criteria for PJI were not fulfilled and antibiotics stopped. In 41 (89.1%) of all hips and in 32 (94.1%) of the confirmed PJIs, all criteria for DAIR were fulfilled. In patients with exogenous PJI, DAIR was performed not more than three days after referral. In haematogenous infections, the duration of symptoms did not exceed 21 days. In 28 hips, a single debridement and in six hips two surgical debridements were required. In 28 (87.5%) of 32 patients, the total treatment duration was three months. Failure was noted in three hips (9%). Long‐term follow‐up results (mean 4.0 years, 1.4 to 10) were available in 30 of 34 (88.2%) confirmed PJIs. The overall successful outcome rate was 91% in 34 hips, and 90% in 30 hips with long‐term follow‐up results. Conclusion Prompt surgical treatment with DAIR, following strict diagnostic and therapeutic criteria, in patients with suspected periprosthetic joint infection, can lead to high rates of success in eradicating the infection.

Long-Term Femoral Bone Remodeling After Cemented Hip Arthroplasty With the Müller Straight Stem in the Operated and Nonoperated Femora

We investigated the cortical bone changes in 35 patients with total hip arthroplasty operated on only for osteoarthritis with more than 10 years of follow-up and with nonrevised femoral components and without radiologic signs of loosening. The mean follow-up was 16 ± 5 years. The thicknesses of femoral cortices were measured medially and laterally at 6 levels from the first postoperative and the last follow-up x-rays. A comparison with 10 patients who had a nonoperated contralateral hip was performed. We found a significant decrease in cortical thicknesses in total hip arthroplasty. The cortical thinning was significant at all periprosthetic levels but less expressed distally. Prosthetic femora were associated with greater cortical thinning as compared with the contralateral nonoperated femora, exceeding that caused by natural aging.

Prospective five-year subsidence analysis of a cementless fully hydroxyapatite-coated femoral hip arthroplasty component

Early subsidence >1.5 mm is considered to be a predictive factor for later aseptic loosening of the femoral component following total hip arthroplasty (THA). The aim of this study was to assess five-year subsidence rates of the cementless hydroxyapatite-coated twinSys® stem (Mathys Ltd., Bettlach, Switzerland). This prospective single-surgeon series examined consecutive patients receiving a twinSys® stem at Maria Middelares Hospital, Belgium. Patients aged >85 years or unable to come to follow-up were excluded. Subsidence was assessed using Ein Bild Roentgen Analyse – Femoral Component Analysis (EBRA-FCA). Additional clinical and radiographic assessments were performed. Follow-ups were prospectively scheduled at two, five, 12, 24, and 60 months. In total, 218 THA (211 patients) were included. At five years, mean subsidence was 0.66 mm (95% CI: 0.43-0.90). Of the 211 patients, 95.2% had an excellent or good Harris Hip Score. There were few radiological changes. Kaplan-Meier analysis indicated five-year stem survival to be 98.4% (95% CI: 97.6-100%). Subsidence levels of the twinSys® femoral stem throughout the five years of follow-up were substantially lower than the 1.5 mm level predictive of aseptic loosening. This was reflected in the high five-year survival rate.

Management of Asymptomatic Bacteriuria, Urinary Catheters and Symptomatic Urinary Tract Infections in Patients Undergoing Surgery for Joint Replacement: A Position Paper of the Expert Group 'Infection' of swissorthopaedics.

In this position paper, we review definitions related to this subject and the corresponding literature. Our recommendations include the following statements. Asymptomatic bacteriuria, asymptomatic leukocyturia, urine discolouration, odd smell or positive nitrite sediments are not an indication for antimicrobial treatment. Antimicrobial treatment of asymptomatic bacteriuria does not prevent periprosthetic joint infection, but is associated with adverse events, costs and antibiotic resistance development. Urine analyses or urine cultures in asymptomatic patients undergoing orthopaedic implants should be avoided. Indwelling urinary catheters are the most frequent reason for healthcare-associated urinary tract infections and should be avoided or removed as soon as possible.