The Impact of Dorsal Root Ganglion Stimulation on Pain Levels and Functionality in Patients With Chronic Postsurgical Knee Pain.

BACKGROUND: Chronic postsurgical pain is a considerable source of disabling neuropathic pain. Rates of knee replacement surgeries are increasing, and many patients report chronic postsurgical pain in their wake. When conventional therapies prove ineffective, neuromodulation options such as dorsal root ganglion stimulation (DRGS) may be used. However, little is known about the effect of DRGS on improvements in quantitative functional outcome parameters. MATERIALS AND METHODS: In a prospective observational study at two pain centers, patients with chronic postsurgical knee pain underwent implantation with a DRGS system after an interdisciplinary multimodal pain program. Ratings of pain, mood, quality of life, and function were captured at baseline and through 12 months of treatment. Quantitative measures (range of motion, walking distance, and pain medication usage) were also recorded. RESULTS: Visual analog scale ratings of pain decreased from 8.6 to 3.0 (p < 0.0001; N = 11), and other pain measures agreed. Quality of life on the 36-Item Short Form Health Survey questionnaire improved from 69.3 to 87.6 (p < 0.0001), whereas the improvement in depression ratings was nonsignificant. International Knee Documentation Committee questionnaire ratings of function improved from 27.7 to 51.7 (p < 0.0001), which aligned with other functional measures. On average, knee range of motion improved by 24.5°, and walking distance dramatically increased from 125 meters to 1481. Cessation of opioids, antidepressants, and/or anticonvulsants was achieved by 73% of participants. CONCLUSIONS: Both subjective-based questionnaire and quantitative examination-based variables were in broad agreement on the value of DRGS in improving functionality and chronic postsurgical pain in the knee. Although this finding is limited by the small sample size, this intervention may have utility in the many cases in which pain becomes problematic after orthopedic knee surgery.

Evaluation of two different semi-automated homogenization techniques in microbiological diagnosis of periprosthetic joint infection: disperser vs. bead milling method.

BACKGROUND: In microbiological diagnosis of periprosthetic joint infection (PJI) there is no consensus regarding the most suitable and optimal number of specimens to be cultured or the most effective technique of tissue processing. This comparative study analysed the accuracy of two semi-automated homogenization methods with special focus on the volume and exact origin of each sample. METHODS: We investigated a total of 722 periprosthetic tissue samples. PJI was defined according to the new scoring system for preoperative and intraoperative criteria. We compared the performance of our routinely used single tissue processing by disposable high-frequency disperser with the bead milling method. RESULTS: Eighty patients were included. Among forty classified PJIs, 34 patients yielded positive culture results. In 23 cases (68%) exact concordant results were generated with both techniques. However, in seven cases (20%) processing by the disperser and in four cases (12%) by bead milling provided additional positive samples, but without significant difference since the major definition criteria were met in all cases. The percentage of positive results was influenced by the volume and origin of the tissue samples. Results for small tissue samples tended to be better using the bead milling method. This might lead to improved preoperative arthroscopic diagnosis, as the volume of biopsies is generally limited. Six patients had negative results due to previous antimicrobial therapy. Forty other patients were classified as aseptic failures. Neither procedure resulted in any contamination. CONCLUSION: Both methods enable reliable processing of tissue samples for diagnosis of PJI and are suitable for routine use.

Microbiological diagnosis of polymicrobial periprosthetic joint infection revealed superiority of investigated tissue samples compared to sonicate fluid generated from the implant surface.

OBJECTIVES: In the microbiological diagnosis of periprosthetic joint infection (PJI), there is much discussion about the methodology of obtaining proper specimens, the processing technique, and suitable culture media. This retrospective study was conducted to analyse the accuracy of our culture techniques. METHODS: Tissue samples and components from 258 patients after revision arthroplasty of the hip, knee, and shoulder were investigated, and the results of tissue cultures (TC) were compared to those of sonicate fluid cultures (SFC). Furthermore, an evaluation was performed of the influence of different culture media on the detection rate. RESULTS: PJI was confirmed in 186 patients. The overall sensitivity of TC was no different to that of SFC (91.3% vs 90.8%, P = 1). In 153 cases (82.3%), TC and SFC showed concordant positive results. Results were discordant in 33 cases (17.7%). When differentiated according to the type of infection, TC showed significantly better results than SFC in detecting polymicrobial infections (97.0% vs 67.0%, P = 0.004). There were also significant differences between the culture media regarding the yield of microorganisms. CONCLUSIONS: TC was more effective in detecting co-infections. The best results were obtained using both TC and SFC. The choice of culture media has a significant influence on the quality of results.

Sonicate fluid inoculated into blood culture bottles does not improve diagnosis of periprosthetic joint infection caused by anaerobes. A retrospective analysis.

BACKGROUND: In microbiological diagnosis of periprosthetic joint infection (PJI) there is much controversial discussion about culture media and incubation time, especially if anaerobic bacteria are the causative agents. This retrospective analysis was conducted to compare the results obtained by inoculation of sonicate fluid from prosthetic components into BD Bactec blood culture bottles with those obtained by our culture method using sensitive supplemented growth media. METHODS: Twenty-eight cases were included in this study. For definition of PJI, the criteria of the Musculoskeletal Infection Society (MSIS) were considered. The quantity and time to positivity of anaerobes detected in sonicate fluid were monitored both from inoculated supplemented liver thioglycollate broth and anaerobic blood culture bottles. Furthermore, phenotypic testing was performed on the antimicrobial activity within the sonicate fluid. RESULTS: The most frequently isolated microbes were Cutibacterium species, followed by Finegoldia magna, Parvimonas micra, Robinsoniella peoriensis, Clostridium species, Peptoniphilus harei and Slackia exigua. In 24 cases, the microorganisms became detectable within five days (median time 3.2 days) when sonicate fluid was incubated in supplemented liver thioglycollate broth, regardless of whether the patients had taken antimicrobial agents prior to surgery. However, when sonicate fluid was inoculated into anaerobic Bactec bottles, the median time to positivity was 7.4 days and only 12 cases (43%) were correctly identified. Sixteen cases remained negative after 14 days of incubation. CONCLUSION: Depending on the pathogen, incubation of sonicate fluid using blood culture bottles can support diagnosis of PJI but compared with our culture medium it is less efficient if anaerobes are the suspected cause of infection. Microbiological expertise is therefore indispensable to ensure reliable detection of these microorganisms in PJI until a gold standard for laboratory handling of anaerobes has been established.

Long-term results of an anatomically implanted hip arthroplasty with a short stem prosthesis (MiniHipTM).

AIM: To evaluate the clinical and radiological outcome nine and ten years after short-stemmed, bone preserving and anatomical hip arthroplasty with the MiniHipTM system. METHODS: In a prospective study, 186 patients underwent hip arthroplasty with a partial neck preserving short stem (MiniHipTM, Corin). Elderly patients were not excluded from this study, thus the mean age at the time of surgery was 59.3 years (range 32 to 82 years). Surgery and the follow-up assessments were performed at two Centers. Up until now, the mean follow-up was 112.5 ± 8.2 mo. The Oxford Hip Score (OHS) and the Hip Dysfunction Osteoarthritis and Outcome Score (HOOS) was assessed pre- and each year after surgery. The clinical follow-up was accompanied by standardized a.p. and axial radiological examinations. Periprosthetic lucencies, hypertrophies within the Gruen zones one to fourteen were assessed. A subsidence of the stem was investigated according to Morray and heterotopic ossifications were assessed according to Brooker. RESULTS: The OHS and HOOS improved from 18 ± 3.3 to 46 ± 2.0 and from 30 ± 8.3 to 95 ± 4.6 points, P < 0.001 respectively. There were no differences regarding age, etiology, friction pairings, etc., (P > 0.05). Two stems were revised due to a symptomatic subsidence four and twelve months postoperatively. Thus, the survivorship for aseptic loosening at nine to ten years was 98.66%. Including one stem revision due to a symptomatic exostosis, bursitis and thigh pain as well as one revision because of a septic stem loosening, the overall survival for the stem with revision for any reason was 97.32%. Besides one asymptomatic patient, radiological signs of a proximal stress-shielding, such as bone resorptions within the proximal Gruen zones, were not noticed. Findings suggesting a distal loading, e.g., bony hypertrophies or bone appositions of more than 2 mm, were also not detected. CONCLUSION: Regarding these first long-term results on the MiniHipTM, the implant performed exceedingly well with a high rate of survivorship for aseptic loosening. Our radiological results within the Gruen zones support the design rationale of the Minihip to provide a reliable metaphyseal anchoring with the expected proximal, more physiological load transfer. This might minimize or exclude a stress shielding which might be associated with thigh pain, proximal bone loss and an increased risk of aseptic loosening. The MiniHipTM is a reliable partial-neck retaining prosthesis with good a clinical long-term outcome in younger as well as elderly patients.

Restoration of the joint geometry and outcome after stemless TESS shoulder arthroplasty.

AIM: To evaluate the joint geometry and the clinical outcome of stemless, anatomical shoulder arthroplasty with the TESS system. METHODS: Twenty-one shoulders with a mean follow-up 18 of months were included. On scaled digital radiographs the premorbid center of rotation (CoR) was assessed and compared to the CoR of the prosthesis by using the MediCAD® software. Additionally, the pre- and post-operative geometry of the CoR was assessed in relation to the glenoid, the acromion as well as to the proximal humerus. Radiological changes, such as radiolucencies, were also assessed. Clinical outcome was assessed with the Constant and DASH score. RESULTS: Both, the Constant and DASH scores improved significantly from 11% to 75% and from 70 to 30 points, P < 0.01 respectively. There were no significant differences regarding age, etiology, cemented or metal-backed glenoids, etc. (P > 0.05). The pre- and postoperative humeral offset, the lateral glenohumeral offset, the height of the CoR, the acromiohumeral distance as well as neck-shaft angle showed no significant changes (P > 0.05). The mean deviation of the CoR of the prosthesis from the anatomic center was 1.0 ± 2.8 mm. Three cases showed a medial deviation of more than 3 mm. These deviations of 5.1, 5.7 and 7.6 mm and were caused by an inaccurate humeral neck cut. These 3 patients showed a relatively poor outcome scoring. CONCLUSION: TESS arthroplasty allows an anatomical joint reconstruction with a very good outcome. Outliers described in this study sensitize the surgeon for an accurate humeral neck cut.