Accurate surgical posterior tibial slope alteration can be achieved in total knee arthroplasty regardless of surgeon skill level or local soft tissue thickness-A retrospective radiograph-based study.

PURPOSE: To retrospectively report on the impact of local soft tissue thickness and surgeon skill level on the accuracy of surgical posterior tibial slope (PTS) alteration achieved in patients undergoing total knee arthroplasty (TKA) utilising lateral knee radiographs. METHODS: Pre- and postoperative radiographs of 82 patients undergoing primary TKA using conventional mechanical alignment technique were measured by two observers and subjected to quality criteria for accurate measurement of the PTS. All patients underwent a standardised surgical approach for PTS alteration: cruciate-retaining (CR) cases with preoperative PTS ≤ 10° were set for reconstruction of the preoperative PTS. Cases indicated for posterior-stabilised (PS) design and/or with a preoperative PTS > 10° were set for 3° of postoperative PTS. Pretibial subcutaneous fat (PSF) and surgeon skill level were analysed for their predictive quality regarding the accuracy of surgical PTS alteration achieved. RESULTS: The overall mean postoperative PTS was significantly lower than the preoperative values (6.2°, SD 2.7 vs. 7.7°, SD 3.2; p = 0.002103). Neither local soft tissue thickness, namely PSF, nor surgeon skill level was found to be a predictor of the accuracy of surgical PTS alteration achieved. Among cases set for PTS reconstruction, 25.9% and 42.6% achieved a postoperative PTS within ±1° and ±2° of preoperative values, respectively. In patients with a PTS > 10° or those indicated for PS design, slope reduction was achieved with a mean postoperative PTS of 6.5°. Furthermore, 14.3% and 32.1% of cases were within ±1° and ±2° of 3, respectively. CONCLUSION: This study demonstrates that accurate surgical alteration of the PTS is possible in TKA regardless of local knee soft tissue thickness or surgeon skill level. This proves the clinical feasibility of both targeted reduction as well as reconstruction of the PTS in TKA. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Identification of risk factors for treatment failure of closed reduction and abduction bracing after first-time total hip arthroplasty dislocation.

INTRODUCTION: After a first-time total hip arthroplasty (THA) dislocation, a closed reduction followed by partial immobilization in an abduction brace is the recommended therapy. Despite modern abduction braces the success rate of conservative therapy is limited and evidence is scarce. The aim of this study was to identify risk factors for failure of conservative treatment after THA dislocation. MATERIAL AND METHODS: Eighty-seven patients, with conservative treatment of a first-time dislocation of a primary or revision THA, were included in this retrospective cohort study. Success was defined as a stable THA for a minimum of 6 months. Re-dislocation, open reduction or revision was defined as failure. The following risk factors were analyzed: gender, age, body mass index (BMI), ASA (American Society of Anesthesiologists) score, time of dislocation, head size, cup orientation, leg length, center of rotation and offset. RESULTS: Sixty-seven percent of all patients experienced a re-dislocation, despite standardized conservative therapy. A BMI ≥ 25 kg/m2, early THA dislocation, and low cup anteversion were associated with a statistically significantly higher risk for re-dislocation. None of the other risk-factors achieved statistical significance. A multifactorial risk-factor analysis was performed to assess whether a cup position outside of Lewinnek's safe zone in combination with gender, BMI and time to dislocation showed statistical significance for re-dislocation. Both BMI ≥ 25 kg/m2 and early dislocation showed a statistically higher failure rate. Cup position and gender were not significant. CONCLUSIONS: BMI ≥ 25 kg/m2, early THA dislocation and low cup anteversion were identified as significant risk factors for failure of conservative treatment with an abduction brace for first-time THA dislocation.

Developmental Hip Dysplasia Treated with Cementless Total Hip Arthroplasty Using a Straight Stem and a Threaded Cup-A Concise Follow-Up, At a Mean of Twenty-Three Years.

We previously reported the 9-year follow-up results of 121 cementless total hip arthroplasties (THAs) from 1990 to 1994 in 93 patients with developmental dysplasia of the hip (DDH). The present study reports the updated long-term results after a mean follow-up of 23 years. Fifty-seven patients (72 hips) were alive and available for follow-up. Since our previous report, nine THAs had been revised. The cumulative implant survivorship of any component was 87% (95% CI, 78-92%). The cumulative probability of not having aseptic cup loosening was 87% (95% CI, 77-93%) and there was no revision surgery for aseptic stem loosening. In three hips (5%), an exchange of the ball and liner due to polyethylene wear was performed after a mean of 12 years. This study demonstrates that cementless THA for DDH with restoration of the hip joint center provides excellent long-term durability.

[Importance of the tibial slope in knee arthroplasty]. / Bedeutung des tibialen Slopes in der Knieendoprothetik.

Notwithstanding the contributions of soft tissue restraints on postoperative kinematics and long-term survival after total knee arthroplasty (TKA), there is an emerging consensus that the underlying anatomy, especially the posterior inclination of the tibial plateau in the sagittal plane (tibial slope), might just have a comparable impact. However, this has not been fully elucidated as yet. Therefore, a thorough literature search, analysis and presentation of current scientific data was conducted. The tibial slope has been shown to relate linearly to the postoperative range of motion and function of the extensor mechanism. Furthermore, it impacts wear of the tibial insert and loosening, as well as instability of the TKA. As no consensus has been reached on the ideal tibial slope, recommendations range from 0° to 10°. Notably, more recent studies favor reconstructing the native, preoperative tibial slope, and the majority of authors advocate that knowledge of this is crucial for optimal TKA surgery.

Assessment of the tibial slope is highly dependent on the type and accuracy of the preceding acquisition.

BACKGROUND: Precise measurement of the tibial slope (TS) is crucial for realignment surgery, ligament reconstruction, and arthroplasty. However, there is little consensus on the ideal assessment. It was hypothesized that the tibial slope changes according to the acquisition technique and both tibial length as well as femoral rotation serve as potential confounders. METHODS: 104 patients (37 women, 67 men; range 12-66 years) were retrospectively selected, of which all patients underwent a 1.5-Tesla MRI and either additional standard lateral radiographs (SLR, n = 52) or posterior stress radiographs (PSR, n = 52) of the index knee. Two blinded observers evaluated the medial tibial slope as the medial TS is primarily used in clinical practice. Additionally, the length of the diaphyseal axis and the extent of radiographic malrotation were measured. RESULTS: Mean TS on MRI was significantly lower compared to radiographs (4.2° ± 2.9° vs. 9.1° ± 3.6°; p < 0.0001). There was a significant correlation between MRI and PSR (p < 0.0001 with r = 0.7), but not with SLR (p = 0.93 with r = 0.24). Tibial length was a significant predictor for the difference between MRI and SLR (regression coefficient ß = - 0.03; p = 0.035), yet not between MRI and PSR (ß = - 0.003; p = 0.9). Femoral rotation proved to be a significant predictor for the agreement between both observers (PSR: ß = 0.14; p = 0.001 and SLR: ß = 0.08; p = 0.04). ICC indicated a high interrater agreement for the radiographic assessment (ICC ≥ 0.72). CONCLUSIONS: There is a substantial variance between MRI and radiographic measurement of the tibial slope. However, as MRI assessment is time-consuming and requires specialized software, instrumented radiographs might be an alternative. Due care has to be taken to ensure that radiographs contain a sufficient tibial length, and femoral rotation is avoided. STUDY DESIGN: Case series (diagnosis); Level of evidence, 4.

Outcome of short versus long interval in two-stage exchange for periprosthetic joint infection: a prospective cohort study.

INTRODUCTION: A two-stage exchange is the standard treatment approach for chronic periprosthetic joint infection (PJI). While a 6-8 week interval is commonly used before reimplantation, the optimal length of the prosthesis-free interval has not yet been determined. We evaluated the influence of a short (< 4 weeks) and long (≥ 4 weeks) interval on reinfection rate and functional outcome of hip and knee PJI. METHODS: In this prospective cohort, patients undergoing two-stage revision for PJI were assigned to prosthesis reimplantation after a short (< 4 weeks) or long (≥ 4 weeks) interval. All patients received standardized antimicrobial therapy, which consisted of antibiogram-adapted, non-biofilm-active antibiotics during the interval and an antimicrobial combination therapy with biofilm-active antibiotics after reimplantation. Follow-up was performed for infection, joint function, pain, need for care and quality of life. RESULTS: Thirty-eight patients undergoing two-stage revision for PJI (18 hips and 20 knees) were included. Short interval was used in 19 patients having a mean interval of 17.9 days (range 7-27 days), long interval in 19 patients having a mean interval of 63.0 days (range 28-204 days). At a mean follow-up of 39.5 months (range 32-48 months), 37 of 38 patients (97.4%) were infection-free. One failure occurred among patients with long interval and none among patients with short interval. Functional results (ROM, HHS, KSS, VAS) and quality of life (SF-36) were similar in both groups. Patients treated with long interval required cumulatively additional 204 inpatient days for nursing care compared to patients with short interval. CONCLUSIONS: This study suggests that two-stage exchange with short interval has a similar outcome than with long interval, when highly active antibiotic therapy is used. Patient inconvenience and care costs due to immobilization were lower when strategies with a short interval were used.

Cerclages after Femoral Osteotomy Are at Risk for Bacterial Colonization during Two-Stage Septic Total Hip Arthroplasty Revision.

Aims: In cases of a two-stage septic total hip arthroplasty (THA) exchange a femoral osteotomy with subsequent cerclage stabilization may be necessary to remove a well-fixed stem. This study aims to investigate the rate of bacterial colonization and risk of infection persistence associated with in situ cerclage hardware in two-stage septic THA exchange. Patients and Methods: Twenty-three patients undergoing two-stage THA exchange between 2011 and 2016 were included in this retrospective cohort study. During the re-implantation procedure synovial fluid, periprosthetic tissue samples and sonicate fluid cultures (SFC) of the cerclage hardware were acquired. Results: Seven of 23 (30%) cerclage-SFC produced a positive bacterial isolation. Six of the seven positive cerclage-SFC were acquired during THA re-implantation. Two of the seven patients (29%) with a positive bacterial isolation from the cerclage hardware underwent a THA-revision for septic complications. The other five patients had their THA in situ at last follow-up. Conclusions: Despite surgical debridement and antimicrobial therapy, a bacterial colonization of cerclage hardware occurs and poses a risk for infection persistence. All cerclage hardware should be removed or exchanged during THA reimplantation.

Reduced culture time and improved isolation rate through culture of sonicate fluid in blood culture bottles.

BACKGROUND AND OBJECTIVE: The aim of this study was to investigate if the cultivation of sonicate fluid (SFC) in blood culture bottles (BCB) leads to a higher rate of bacterial isolations than agar plate culture (APC) and to investigate whether the utilization of BCB leads to a reduction in culture time. METHODS: We performed a retrospective analysis of 206 revision total knee and total hip arthroplasty patients comparing the results of both synovial fluid culture and SFC in both BCB and conventional APC. RESULTS: The use of BCB improved both the rate of positive bacterial isolations and reduced the culture time for synovial fluid as well as SFC. Fifty-one patients showed a bacterial isolation in SFC-APC and 101 in SFC-BCB. For synovial fluid 24 patients showed a bacterial isolation on APC and 37 showed a bacterial isolation in BCB. The synovial fluid cultures showed growth on APC after an average of 2.8 days vs. 1.8 days in BCB. The SFC-APC showed growth after an average of 4.2 days vs. 2.9 days for SFC-BCB. CONCLUSIONS: The culture of synovial and sonicate fluid in BCB leads to more positive bacterial isolations and quicker bacterial growth than conventional agar plate cultures.

Inadequacy of Joint Aspiration for Detection of Persistent Periprosthetic Infection During Two-Stage Septic Revision Knee Surgery.

Despite the lack of validation, synovial aspiration remains a common practice during 2-stage septic revision total knee arthroplasty (TKA). The goal of this study was to investigate the diagnostic validity of synovial polymethylmethacrylate (PMMA) spacer aspiration of temporary knee arthrodesis to detect persistent periprosthetic joint infection before TKA reimplantation. This retrospective cohort study included 73 consecutive patients who underwent 2-stage septic revision TKA according to a standard protocol. After explantation surgery, including temporary arthrodesis with an intramedullary stabilized PMMA spacer, all patients had synovial aspiration 2 weeks before reimplantation to exclude persistent periprosthetic joint infection. Patients had a 2-week antibiotic holiday before aspiration. Sensitivity and specificity of the synovial PMMA spacer joint aspiration for the detection of periprosthetic joint infection were determined and referenced against intraoperative microbiologic and histologic samples obtained at second-stage surgery. Sensitivity of the synovial PMMA spacer aspiration was 21%. Because of poor diagnostic validity, synovial PMMA spacer aspiration cannot be recommended for routine exclusion of persistent periprosthetic joint infection before TKA reimplantation. Therefore, exclusion of persistent periprosthetic joint infection should be supplemented by other diagnostic methods, and it is not necessary to delay TKA reimplantation for PMMA spacer aspiration. [Orthopedics. 2017; 40(4):231-234.].

Increased rate of bacterial colonization on PE-components in total joint arthroplasty: An evaluation through sonication.

BACKGROUND: It is currently unclear if an isolated exchange of the mobile components, in cases of periprosthetic joint infection (PJI), leads to a complete eradication of all bacteria or if residual bacteria remain attached to the retained components? OBJECTIVE: The purpose of this study was to investigate if bacteria only adhere to certain components or materials, or if they are ubiquitously distributed throughout the joint. METHODS: Twenty hundred and eighty four patients undergoing revision total hip or total knee arthroplasty surgery were included in this retrospective cohort study. Synovial fluid cultures, periprosthetic tissue cultures, histological samples and sonicate fluid cultures (SFC) from the individual endoprosthetic components were acquired. The isolated bacterial species were recorded according to their endoprosthetic component of origin. RESULTS: In 72% of all cases with multiple SFC, the cultures were concordant with all samples being either homogenously negative or showing positive bacterial growth. The polyethylene (PE) components showed a significantly higher rate of bacterial isolation than the non-mobile components. All components and materials showed bacterial colonization, however between all other components or materials were not statistically significant. CONCLUSIONS: PE-components show a higher rate of bacterial isolation than other components. If an isolated bearing exchange is performed this should be supplemented by adequate antimicrobial therapy.

Postoperative Increased Loading Leads to an Alteration in the Radiological Mechanical Axis After Total Knee Arthroplasty.

BACKGROUND: Standing long-leg radiographs allow assessment of the mechanical axis in the frontal plane before and after total knee arthroplasty (TKA). An alteration in loading, and hence in the forces acting on the knee joint, occurs postoperatively. We therefore postulated that the mechanical axis measured in the long-leg standing radiograph would change within the first year after TKA. METHODS: Standing long-leg radiographs of 156 patients were performed 7 days, 3 months, and 12 months after TKA with determination of mechanical axis of the lower limb. RESULTS: Seven days after surgery, the mechanical axis amounted 0.8° ± 1.7° valgus. Three months after the operation, at 1.3° ± 1.3° varus, it was significantly different (P < .001) from the primary measurement. No further alteration in the mechanical axis occurred during the first year after TKA. This difference was even more pronounced (P < .001) in patients with a postoperative lack of complete extension. Seven days after surgery, they had a valgus axis deviation of 1.6° ± 1.6°; after 3 months, the measurement amounted 1.2° ± 1.3° varus. CONCLUSION: Measured by a standing long-leg radiograph, the frontal mechanical axis after TKA changes over time. The predictive power of a standing long-leg radiograph in the first week after surgery is limited because limb loading is altered because of pain and is therefore nonphysiological. The actual mechanical axis resulting after TKA can only be assessed in a standing long-leg radiograph at physiological loading.

Validation of Synovial Aspiration in Girdlestone Hips for Detection of Infection Persistence in Patients Undergoing 2-Stage Revision Total Hip Arthroplasty.

BACKGROUND: The aim of this study was to assess the diagnostic performance of synovial aspiration in Girdlestone hips, without a Polymethylmethacrylate (PMMA) spacer, for the detection of infection persistence before total hip arthroplasty (THA) reimplantation. METHODS: Seventy-four patients undergoing stage revision THA surgery were included in this retrospective cohort study. Both synovial cultures and serum C-reactive protein values were acquired before explantation of the THA and of the Girdlestone hip before reimplantation. RESULTS: The diagnostic performance of the synovial aspiration of the Girdlestone hip achieved a sensitivity of only 13% and a specificity of 98%. The determination of the serum C-reactive protein value for Girdlestone hips achieved a sensitivity of 95% and a specificity of only 20%. CONCLUSIONS: Our data show that the Girdlestone aspiration can neither reliably confirm nor exclude a persistence of infection.

Influence of the Type of Sagittal Profile on Clinical Results of Lumbar Total Disk Replacement After a Mean Follow-Up of 39 Months.

STUDY DESIGN: Retrospective analysis of clinical and radiologic data of a prospective cohort study. OBJECTIVE: To research the clinical differences after lumbar total disk replacement (TDR) with respect to the preoperative global and the adaptation at the local sagittal profile (SP) of the spine. SUMMARY OF BACKGROUND DATA: It was suggested that facet loads and degeneration are dependent on epidemiologically defined types of SP. Moreover, the success of TDR was related to segmental facet joint loads. The influences of the preoperative SP or of the changes of the local SP after TDR on the clinical outcome after TDR remain unclear. METHODS: Fifty-two patients included in a prospective cohort study regarding lumbar single-level TDR L4/5 (n=22) or L5/S1 (n=30) because of degenerative disk disease (Modic ≤2 degrees) were clinically (visual analog scale for back, leg, and overall pain; Oswestry Disability Index) and radiologically (extension-flexion radiographs, plain-spine, and whole-spine lateral radiographs in upright standing position) reevaluated after a minimum follow-up of 24 (24-69) months. On the basis of preoperative plain radiographs in upright standing position, patients were retrospectively assigned to 4 groups according to the individual sagittal profile type (SPT). In patients with persistent back pain, a facet infiltration at the index level was performed. RESULTS: For all patients, an SPT could be defined. Global SP did not change compared with the preoperative state. All groups improved clinically over follow-up. At the last follow-up, types 1 and 4 demonstrated significantly inferior scores for pain and function. TDR-induced changes at the superior adjacent segment and the posterior disk height at the index level were also correlated to inferior clinical results. Infiltration test was positive in type 1-4: 67%, 40%, 33%, and 75%, respectively, of the symptomatic patients. CONCLUSIONS: We suggest SPTs 1 and 4 to represent a contraindication for lumbar TDR of levels L4/5 or L5/S1. Local adaptation in the adjacent segment to TDR may influence the clinical outcome as well.

Can discoblock replace discography for identifying painful degenerated discs?

OBJECTIVES: The aim of the present study was to intra-individually compare provocative discography and discoblock (disc analgesia) of idiopathic degenerated discs (IDD) results to each other, to clinical parameters, and to MRI findings. By this the value of both diagnostic features should be critically reevaluated. METHODS: 31 intervertebral IDD (Pfirrmann III°-IV°) of 26 patients were analyzed for surgery decision making by combined discoblock/discography procedure in an open MRI at 1T. A correlation analysis was performed between the Dallas Discogram Scale, pain discrimination score (PDS: concordant/discordant/no pain), positive discoblock (Numerical Rating Scale [NRS] reduction by ≥ 3, 60 min after intervention), presence of Modic changes or high intensity zones (HIZ), patient sex and age, intervention level, injection pressure and discography endpoint analysis (pain/pressure/anatomic/volume). RESULTS: Concordant pain could be evoked in 35% of the IDDs whereas discoblock was positive in 64%. Patients' age, sex, Dallas I, Dallas II, and Pfirrmann scores, as well as the presence of HIZ did not correlate to PDS or discoblock results. Discoblock correlated positively to concordant pain. Further positive correlation was found between PDS and intervention level/pressure, between discoblock and Modic changes/discography endpoint as well as between HIZ and discography endpoint. CONCLUSIONS: We suggest discoblock to be an additional tool for surgery decision making in patients with IDD because it correlates to concordant pain evoked by provocative discography as well as to presence of Modic changes. Additionally, assessment of a release instead of provocation of pain can be of advantage.

Stand-alone anterior versus anteroposterior lumbar interbody single-level fusion after a mean follow-up of 41 months.

STUDY DESIGN: Prospective cohort study comparing evaluations of single-level anterior lumbar interbody fusion (ALIF) versus anteroposterior lumbar fusion (APLF). OBJECTIVE: To clinically and radiologically compare the outcome after angle-stable, locked, stand-alone ALIF with that obtained after APLF, in cases with degenerative disc disease (DDD). SUMMARY OF BACKGROUND DATA: Fusion rates have been reported to be highest after interbody fusion with transpedicular fixation. However, transpedicular fixation is linked to significant damage of the paravertebral muscles, to screw displacement-related neurological and vascular complications, and to an increased rate of adjacent segment degeneration. When performed as a stand-alone procedure, the disadvantages of transpedicular fixation can be completely avoided by ALIF. METHODS: Eighty patients with chronic low-back pain due to a single-level DDD (Modic ≥2) and facet joint arthritis (Fujiwara ≥3) were enrolled in this study. Forty patients received an anteroposterior fusion (ALIF with transpedicular fixation: APLF group) and 40 patients (ALIF group) were treated with a stand-alone ALIF using the Synfix-LR device. At 7 days, 3, 6, 12, and 24 months, and at a mean follow-up of 41 months, patients were clinically (visual analog scale, Oswestry Low Back Pain Disability Index, satisfaction) and radiologically (x-ray, and at 12 months, thin-slice computed tomography) compared. RESULTS: Blood loss and duration of surgery were significantly lower in the ALIF group (P<0.001). Visual analog scale and Oswestry Low Back Pain Disability Index improved significantly over time (analysis of variance, P<0.001) in both groups, but both scores were significantly better in ALIF group (analysis of variance, P<0.001). Patients' satisfaction consistently ranked higher in the ALIF group (P=0.042 at 12 mo). No significant difference was found in the fusion rate throughout the study. CONCLUSIONS: Stand-alone ALIF leads to better clinical results than APLF, without differences in fusion rates after 41 months. Therefore, when a posterior approach is not needed for decompression or reposition, we suggest performing a stand-alone ALIF in cases with single-level DDD.