Hanssen, Arlen D.

Aims There is little information regarding the risk of a patient developing prosthetic joint infection (PJI) after primary total knee arthroplasty (TKA) when the patient has previously experienced PJI of a TKA or total hip arthroplasty (THA) in another joint. The goal of this study was to compare the risk of PJI of primary TKA in this patient population against matched controls. Patients and Methods We retrospectively reviewed 95 patients (102 primary TKAs) treated between 2000 and 2014 with a history of PJI in another TKA or THA. A total of 50 patients (53%) were female. Mean age was 69 years (45 to 88) with a mean body mass index (BMI) of 36 kg/m 2 (22 to 59). In total, 27% of patients were on chronic antibiotic suppression. Mean follow-up was six years (2 to 16). We 1:3 matched these (for age, sex, BMI, and surgical year) to 306 primary TKAs performed in 306 patients with a THA or TKA of another joint without a subsequent PJI. Competing risk with death was used for statistical analysis. Multivariate analysis was followed to evaluate risk factors for PJI in the study cohort. Results The cumulative incidence of PJI in the study cohort (6.1%) was significantly higher than the matched cohort (2.6%) at ten years (hazard ratio (HR) 3.3; 95% confidence interval 1.18 to 8.97; p = 0.02). Host grade in the study group was not a significant risk factor for PJI. Patients on chronic suppression had a higher rate of PJI (HR 15; p = 0.002), with six of the seven patients developing PJI in the study group being on chronic suppression. The new infecting microorganism was the same as the previous in only two of seven patients. Conclusion In this matched cohort study, patients undergoing a clean primary TKA with a history of TKA or THA PJI in another joint had a three-fold higher risk of PJI compared with matched controls with ten-year cumulative incidence of 6.1%. The risk of PJI was 15-fold higher in patients on chronic antibiotic suppression; further investigation into reasons for this and mitigation strategies are recommended. Cite this article: Bone Joint J 2019;101-B(7 Supple C):91–97

Background: Marlex mesh reconstruction of the extensor mechanism via a stepwise surgical approach is a viable option to treat disruption of the extensor mechanism after total knee arthroplasty (TKA). Description: Extensor mechanism reconstruction with mesh involves a stepwise surgical approach with a particular monofilament polypropylene mesh (Marlex; C.R. Bard). Prior to incision, the 10 × 14-in (25 × 36-cm) sheet of Marlex mesh is rolled onto itself 8 to 10 times and sewn together. If the tibia is not being revised, a burr is utilized to create a trough in the tibia. Five centimeters of the tapered portion of the mesh are predipped in bone cement. The remaining cement is inserted into the trough. The tapered portion of the mesh is inserted into the tibial trough, ensuring that the mesh is fully seated. After the cement has cured, a lag screw is placed across the mesh and cement and into host bone. If the tibia is being revised at the time of the Marlex mesh reconstruction, the 5 cm of predipped mesh is placed anteriorly in the medullary canal in line with the tibial crest. The remaining procedure is similar regardless of whether the components are revised. At the level of the joint, it is essential to ensure that the mesh is covered with host tissue. Next, the proximal reconstruction, which involves mobilizing the vastus lateralis and vastus medialis obliquus (VMO) distally by releasing all ventral and dorsal soft-tissue adhesions off the muscle bellies, is completed. Finally, the mesh is unitized to the vastus lateralis. With the limb maintained in full extension, the mesh is pulled directly proximally while another assistant pulls the vastus lateralis distally and medially. The vastus lateralis is deep, and the mesh is directly on top of it. Multiple nonabsorbable sutures are placed through the mesh and vastus lateralis. The VMO is then pulled distally and laterally over the mesh (which is now unitized to the vastus lateralis) by an assistant. Multiple nonabsorbable sutures (usually 8) are placed through the VMO, through the mesh, and through the vastus lateralis, unitizing the entire construct. Alternatives: Nonoperative treatments include a drop-lock hinge brace or knee immobilizer. Operative treatments include whole extensor mechanism allograft reconstruction or Achilles tendon allograft reconstruction. Rationale: The procedure avoids the limitations of allograft with regard to availability, cost, and risk of disease transmission. The technique is reproducible and cost-effective, and it has excellent functional and survivorship outcomes.

Aims Modular dual-mobility constructs reduce the risk of dislocation after revision total hip arthroplasty (THA). However, questions about metal ions from the cobalt-chromium (CoCr) liner persist, and are particularly germane to patients being revised for adverse local tissue reactions (ALTR) to metal. We determined the early- to mid-term serum Co and Cr levels after modular dual-mobility components were used in revision and complex primary THAs, and specifically included patients revised for ALTR. Patients and Methods Serum Co and Cr levels were measured prospectively in 24 patients with a modular dual-mobility construct and a ceramic femoral head. Patients with CoCr heads or contralateral THAs with CoCr heads were excluded. The mean age was 63 years (35 to 83), with 13 patients (54%) being female. The mean follow-up was four years (2 to 7). Indications for modular dual-mobility were prosthetic joint infection treated with two-stage exchange and subsequent reimplantation (n = 8), ALTR revision (n = 7), complex primary THA (n = 7), recurrent instability (n = 1), and periprosthetic femoral fracture (n = 1). The mean preoperative Co and Cr in patients revised for an ALTR were 29.7 μg/l (2 to 146) and 21.5 μg/l (1 to 113), respectively. Results Mean Co and Cr levels were 0.30 μg/l and 0.76 μg/l, respectively, at the most recent follow-up. No patient had a Co level ≥ 1 μg/l. Only one patient had a Cr level ≥ 1 μg/l. That patient’s Cr level was 12 μg/l at 57 months after revision THA for ALTR (and decreased ten-fold from a preoperative Cr of 113 μg/l). Conclusion At a mean of four years, no patient with a modular dual-mobility construct and ceramic femoral head had elevated Co levels, including seven patients revised specifically for ALTR. While further studies are required, we support the selective use of a modular dual-mobility construct in revision and complex primary THAs for patients at high risk for instability. Cite this article: Bone Joint J 2019;101-B(6 Supple B):57–61.

Background: Cementation of a constrained liner is a viable option for treating instability after total hip arthroplasty (THA) when the acetabular component is well fixed and well aligned. However, concerns regarding long-term mechanical failure and recurrent instability remain. The aim of this study was to evaluate the long-term survivorship, complications, and clinical and radiographic outcomes of constrained polyethylene liners cemented into well-fixed acetabular components at the time of revision THA. Methods: We identified 125 cases in which a constrained liner of 1 design was cemented into a retained, osseointegrated acetabular component during revision THA between 1998 and 2006. The mean patient age at revision was 70 years. Mean follow-up was 7 years. Survivorship data, risk of instability, and clinical and radiographic outcomes were analyzed. Results: Survivorship free from revision for instability was 86% at 5 years and 81% at 10 years. Survivorship free from aseptic acetabular component revision was 78% at 5 years and 65% at 10 years, with the most common failure mechanism being dissociation of the constrained liner from the acetabular component. Survivorship free from revision for any reason was 76% at 5 years and 60% at 10 years. The most common complications were instability and periprosthetic joint infection, with cumulative incidences at 7 years of 18% and 11%, respectively. Harris hip scores did not significantly improve. Cup position did not affect implant survivorship or risk of dislocation. Conclusions: Cementing a constrained liner into a retained acetabular shell at the time of revision THA has durable long-term results, with 8 in 10 patients free from instability at 10 years. Aseptic acetabular survivorship was worse (65%) at 10 years, primarily due to dissociation of the constrained liner from the acetabular component. Level of Evidence: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Background: Two-stage exchange is the most common form of treatment of chronic infection following total hip arthroplasty (THA). We examined the prevalence of, and risk factors associated with, hip instability following 2-stage exchange as well as the fate of reimplanted hip prostheses that dislocated. Methods: Data on 515 2-stage exchange THAs performed between 2000 and 2014 at a single institution were retrospectively reviewed. Risk factors for instability as well as postoperative reoperations and revisions were analyzed. The impact of dislocation on these outcomes was evaluated as well. The mean age at the time of reimplantation was 65 years, and the mean duration of follow-up was 5 years (range, 2 to 15 years). Results: Dislocation occurred in 52 hips following reimplantation (cumulative probability = 8.9% at 1 year). There was a higher risk of instability in women (hazard ratio [HR] = 1.8, p = 0.038) and in those who had a history of dislocation prior to the 2-stage revision (HR = 5.1, p < 0.001). Younger age, body mass index, number of previous operations, spacer type, surgical approach, use of a constrained liner, femoral head diameter, and persistent or recurrent infection were not found to be significant risk factors. Patients with an absent or ununited greater trochanter or abductor deficiency also had a higher rate of dislocation (HR = 30, p < 0.001), as did patients who underwent reimplantation with a megaprosthesis (HR = 6.0, p < 0.001). The risk of additional reoperations (HR = 121, p < 0.001) and revision surgery (HR = 13, p < 0.001) was significantly higher in patients who experienced a dislocation after the 2-stage exchange. Conclusions: Dislocation after 2-stage exchange THA continues to be a major concern, with the 1-year cumulative probability found to be 9% in the present study. Female sex, a history of dislocation, an absent or ununited greater trochanter or abductor deficiency, and reimplantation with a megaprosthesis were identified as risk factors for dislocation. There is a remarkable 121-fold increase in the rate of reoperations and a 13-fold increase in the rate of revisions in hips that dislocated after 2-stage exchange THA. Level of Evidence: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Background: For patients undergoing 2-stage exchange for the treatment of periprosthetic joint infection (PJI) following total knee arthroplasty, the long-term risk of reinfection and mechanical failure and long-term clinical outcomes are not well known. The purpose of our study was to determine the long-term clinical results of 2-stage exchange for PJI following total knee arthroplasty. Methods: We identified 245 knees that had undergone total knee arthroplasty and were subsequently treated with 2-stage exchange due to infection during the period of 1991 to 2006; the cohort had no prior treatment for PJI. Major, or 4 of 6 minor, Musculoskeletal Infection Society (MSIS) diagnostic criteria were fulfilled by 179 (73%) of the knees. The cumulative incidence of reinfection and of aseptic revision, accounting for the competing risk of death, were calculated. Risk factors for reinfection were evaluated using Cox proportional hazards regression. Knee Society Score (KSS) values were calculated. The mean age at spacer insertion was 68 years; 50% of the patients were female. The mean follow-up was 14 years (range, 2 to 25 years) following reimplantation. Results: The cumulative incidence of reinfection was 4% at 1 year, 14% at 5 years, 16% at 10 years, and 17% at 15 years. Factors that were predictive of reinfection included a body mass index of ≥30 kg/m 2 (hazard ratio [HR], 3.1; p < 0.01), previous revision surgery (HR, 2.8; p < 0.01), and a McPherson host grade of C (HR, 2.5; p = 0.04). The cumulative incidence of aseptic revision for loosening was 2% at 5 years, 5% at 10 years, and 7% at 15 years. Femoral (HR, 5.0; p = 0.04) and tibial (HR, 6.7; p < 0.01) bone-grafting at reimplantation were predictive of aseptic failure. The most common complications were wound-healing issues, requiring reoperation in 12 (5%) of the knees. The rate of death at 2 years following reimplantation was 11%. The mean KSS improved from 45 at PJI diagnosis to 76 at 10 years following reimplantation (p < 0.01). Conclusions: Long-term reinfection rates following 2-stage exchange for PJI after total knee arthroplasty were similar to those of shorter-term reports and were maintained out to 15 years. Mechanical failure rates were low if bone loss was addressed at the time of reimplantation. Improvements in clinical outcomes were maintained at long-term follow-up. Level of Evidence: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Background: Limited data exist that show the long-term risks of reinfection and mechanical failure with a contemporary 2-stage exchange protocol for periprosthetic joint infection following total hip arthroplasty. The purpose of this study was to determine the long-term reinfection and mechanical failure rates of 2-stage exchange for periprosthetic joint infection after total hip arthroplasty. Methods: We identified 164 hips (162 patients) with infection after total hip arthroplasty between 1991 and 2006 treated with a 2-stage exchange protocol with no prior treatment for periprosthetic joint infection. With regard to Musculoskeletal Infection Society diagnostic criteria, at least 1 major criterion or 4 of 6 minor criteria were fulfilled in 129 hips (79%). The cumulative incidence with a competing risk of death was calculated for reinfection, aseptic revisions, and all-cause revisions. The risk factors for reinfection were evaluated using Cox proportional hazards regression. Harris hip scores were calculated. The mean age at the time of spacer insertion was 68 years, and 35% of the patients were female. Excluding the patients with <2 years of follow-up, the mean follow-up was 12 years (range, 2 to 21 years). Results: The cumulative incidence of recurrence of infection was 10% at 1 year, 14% at 5 years, and 15% at 10 and 15 years. Seventeen patients (11%) used chronic antibiotic suppression (>6 months), with 7 (41%) of these having recurrent infection at the time of the latest follow-up. Use of chronic antibiotic suppression was the only predictive factor for reinfection (hazard ratio, 4.5 [95% confidence interval (CI), 1.9 to 10.9]; p = 0.001). The cumulative incidence of aseptic femoral and acetabular revisions was 2.6% at 5 years and 3.3% at 10 and 15 years. The cumulative incidence of all-cause revisions was 15% at 5 years and 16% at 10 and 15 years. Dislocation was the most common complication, with 28 dislocations occurring in 20 patients (12%). The mean Harris hip score improved from 52 points prior to spacer insertion to 70 points at 15 years after reimplantation (p < 0.01). Conclusions: The rate of recurrence of infection of 15% for up to 15 years after total hip arthroplasty was similar to previous shorter-term reports of 2-stage exchange for periprosthetic joint infection. Surgeons should anticipate mitigating instability after reimplantation. Implant survivorship free of aseptic loosening and clinical outcomes were preserved for the long term. The role of chronic antibiotic suppression in the long-term treatment of periprosthetic joint infection requires further investigation. Level of Evidence: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

AimsThe results of irrigation and debridement with component retention (IDCR) in the treatment of acutely infected total knee arthroplasties (TKAs) have been variable. The aim of this study was to assess the outcome after IDCR when combined with chronic antibiotic suppression. We also evaluated survivorship free from subsequent infection, removal of the components, and death, as well as the risk factors for failure.Patients and MethodsThis was a single-centre retrospective review of 134 infected primary TKAs that were treated with IDCR. Infections within four weeks of the procedure were defined as acute postoperative infections, and those occurring more than four weeks after the procedure with symptoms for less than three weeks were defined as acute haematogenous infections. Patients were treated with intravenous antibiotics for four to six weeks, followed by chronic oral antibiotic suppression. Estimates of survival were made using a competing risk analysis. The mean follow-up was five years (2.1 to 13).ResultsThe infection was an acute postoperative infection in 23 TKAs and an acute haematogenous infection in 111 TKAs. The incidence of subsequent infection was 36% in those with an acute postoperative infection and 33% in those with a haematogenous infection, five years postoperatively (p = 0.40). Age < 60 years increased the risk of subsequent infection (hazard ratio (HR) 2.4; p = 0.009) and removal of the components (HR 2.8; p = 0.007). Infection with a staphylococcal species increased the risk of subsequent infection (HR 3.6; p < 0.001), and removal of the components (HR 3.2; p = 0.002). Musculoskeletal Infection Society host type and local extremity grade, body mass index (BMI), the duration of symptoms, gender, and the presence of a monoblock tibial component had no significant effect on the outcome.ConclusionIn a rigorously defined group of acute periprosthetic infections after TKA treated with IDCR and chronic antibiotic suppression, the infection-free survival at five years was 66%. The greatest risk factor for failure was an infection with a staphylococcal species, followed by age of < 60 years. Cite this article: Bone Joint J 2018;100-B:1471–76.

Background: Periprosthetic joint infection (PJI) of the knee with concurrent disruption of the extensor mechanism is a devastating complication. Historically, knees with such complications have been salvaged with use of an arthrodesis or amputation. The purpose of this study was to assess the survival and functional outcomes of a 2-stage exchange arthroplasty combined with knitted monofilament polypropylene (Marlex; C.R. Bard) mesh reconstruction of the extensor mechanism. Methods: From 2000 to 2015, 16 patients underwent a 2-stage exchange arthroplasty and Marlex-mesh reconstruction for PJI with an extensor mechanism disruption. The study included 9 male patients and 7 female patients with a mean age at the time of reimplantation and mesh reconstruction of 64 years. The mean follow-up was 4 years. PJI was diagnosed on the basis of the Musculoskeletal Infection Society criteria. Clinical outcomes, including survivorship, Knee Society Score (KSS) results, and complications, were assessed. Results: Of 16 reconstructions, 13 were in place at the time of the latest follow-up. At 2 years, survivorship free of mesh failure was 86%, survivorship free of PJI was 87%, and survivorship free of PJI or mesh failure was 75%. The mean KSS improved from 48 prior to resection to 74 after mesh reconstruction and reimplantation. The mean extensor lag improved from 31° prior to resection to 3° after mesh reconstruction. Two patients required mesh revision, 1 patient required an above-the-knee amputation for complex wound complications related to reinfection, 1 patient developed a reinfection requiring irrigation and debridement, and 1 patient developed a superficial infection that required debridement. Conclusions: Two-stage exchange arthroplasty combined with Marlex-mesh reconstruction of the extensor mechanism is a viable alternative to knee arthrodesis or amputation. At 2 years, 75% of mesh reconstructions were in place and without evidence of PJI. Moreover, the functional outcomes were improved, with a negligible extensor lag. Level of Evidence: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Background: Disruption of the extensor mechanism after total knee arthroplasty (TKA) is debilitating, and the reported results of numerous reconstructive options have varied. We previously reported the early results of 13 patients who underwent reconstruction of the extensor mechanism with use of Marlex mesh. The purpose of the current study was to assess results in a larger cohort of patients, with an emphasis on the survivorship of the mesh, clinical results, and complications. Methods: During the period of 2000 to 2015 at a single tertiary care academic institution, 77 patients (77 TKAs) underwent reconstruction with use of Marlex mesh for an extensor mechanism disruption (27 quadriceps tendon disruptions, 40 patellar tendon disruptions, and 10 patellar fractures). The mean patient age at the time of reconstruction was 65 years; 70% of the patients were female. The mean body mass index was 35 kg/m 2 . The mean follow-up was 4 years. Eighteen (23%) of the patients underwent mesh reconstruction with the primary TKA in place, and 59 (77%) had mesh reconstruction at the time of revision TKA. The mean time between disruption and reconstruction was 7 months. Twenty (26%) of the patients had previously undergone attempted extensor mechanism reconstruction at outside institutions. Results: Sixty-five of the 77 mesh reconstructions were in place at the time of the latest follow-up. Twelve patients experienced a failure that required mesh revision: 5 for patellar tendon rupture, 5 for quadriceps tendon rupture, and 2 for symptomatic lengthening. Four additional patients with mesh failure were treated nonoperatively with bracing. The 2-year survivorship free of mesh revision was 86% for patients with no prior reconstruction and 95% for patients with previous reconstructions of the extensor mechanism that did not involve Marlex mesh. Knee Society Score (KSS) results significantly improved following reconstruction (p < 0.001). Extensor lag improved by a mean of 26°, with mean postoperative extensor lag measuring 9° (p < 0.001). Conclusions: Reconstruction of the extensor mechanism with use of Marlex mesh is a viable option in patients with catastrophic disruption after TKA. At the time of the latest follow-up, 84% of the mesh reconstructions were in place and the functional outcomes were excellent, with mean improvement in extensor lag of 26°. Extended follow-up is required, but the results of this large series with a mean follow-up of 4 years are encouraging. Level of Evidence: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.