Total knee arthroplasty after distal femoral osteotomy long-term survivorship and clinical outcomes.

AIMS: There is little literature about total knee arthroplasty (TKA) after distal femoral osteotomy (DFO). Consequently, the purpose of this study was to analyze the outcomes of TKA after DFO, with particular emphasis on: survivorship free from aseptic loosening, revision, or any re-operation; complications; radiological results; and clinical outcome. PATIENTS AND METHODS: We retrospectively reviewed 29 patients (17 women, 12 men) from our total joint registry who had undergone 31 cemented TKAs after a DFO between 2000 and 2012. Their mean age at TKA was 51 years (22 to 76) and their mean body mass index 32 kg/m2 (20 to 45). The mean time between DFO and TKA was ten years (2 to 20). The mean follow-up from TKA was ten years (2 to 16). The prostheses were posterior-stabilized in 77%, varus-valgus constraint (VVC) in 13%, and cruciate-retaining in 10%. While no patient had metaphyseal fixation (e.g. cones or sleeves), 16% needed a femoral stem. RESULTS: The ten-year survivorship was 95% with aseptic loosening as the endpoint, 88% with revision for any reason as the endpoint, and 81% with re-operation for any reason as the endpoint. Three TKAs were revised for instability (n = 2) and aseptic tibial loosening (n = 1). No femoral component was revised for aseptic loosening. Patients under the age of 50 years were at greater risk of revision for any reason (hazard ratio 7; p = 0.03). There were two additional re-operations (6%) and four complications (13%), including three manipulations under anaesthetic (MUA; 10%). The Knee Society scores improved from a mean of 50 preoperatively (32 to 68) to a mean of 93 postoperatively (76 to 100; p < 0.001). CONCLUSION: A cemented posterior-stabilized TKA has an 88% ten-year survivorship with revision for any reason as the endpoint. No femoral component was revised for aseptic loosening. Patients under the age of 50 years have a greater risk of revision. The clinical outcome was significantly improved but balancing the knee was challenging in 13% of TKAs requiring VVC. Overall, 10% of TKAs needed an MUA, and 6% of TKAs were revised for instability. Cite this article: Bone Joint J 2019;101-B:660-666.

Uniformly low serum cobalt levels after modular dual-mobility total hip arthroplasties with ceramic heads: a prospective study in high-risk patients.

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.

Intravenous tranexamic acid safely and effectively reduces transfusion rates in revision total hip arthroplasty.

AIMS: Tranexamic acid (TXA) has been shown to significantly reduce transfusion rates in primary total hip arthroplasties (THAs), but high-quality evidence is limited in the revision setting. The purpose of the current study was to compare the rate of blood transfusions and symptomatic venous thromboembolic events (VTEs) in a large cohort of revision THAs treated with or without intravenous (IV) TXA. PATIENTS AND METHODS: We performed a retrospective review of 3264 revision THAs (2645 patients) between 2005 and 2014, of which 1142 procedures received IV TXA (1 g at incision and 1 g at closure). The mean age in the revision group with TXA was 65 years (28 to 95), with 579 female patients (51%). The mean age in the revision group treated without TXA was 67 years (21 to 98), with 1160 female patients (55%). Outcomes analyzed included rates of transfusion and symptomatic VTEs between procedures undertaken with and without TXA. These comparisons were performed for the overall cohort, as well as within cases subcategorized for aseptic or septic aetiologies. A propensity score was developed to minimize bias between groups and utilized age at revision THA, sex, body mass index, American Society of Anesthesiologists (ASA) score, preoperative anticoagulation, and year of surgery. RESULTS: Tranexamic acid significantly and substantially reduced the rate of blood transfusions after revision THA overall from 54% to 26% (p < 0.001; adjusted relative risk (RR) 1.6; 95% confidence interval (CI) 1.3 to 1.9), with a significant reduction in both aseptic (49% to 18%; p < 0.001) and septic (73% to 53%; p = 0.04) revisions. The rate of VTE was minimal overall, with three events (0.3%) in the TXA group and four events (0.2%) in the non-TXA group. There were no significant differences in VTE rates based on TXA use or aetiology of revision. CONCLUSION: Intravenous TXA significantly reduced transfusion rates during all-cause revision THAs, including a subgroup analysis of both aseptic and septic cohorts. Adjusted risk using propensity modelling showed no statistical difference in rates of VTEs between either group. Cite this article: Bone Joint J 2019;100-B(6 Supple B):104-109.

Reliable outcomes and survivorship of unicompartmental knee arthroplasty for isolated compartment osteonecrosis.

Aims: Primary (or spontaneous) and secondary osteonecrosis of the knee can lead to severe joint degeneration, for which either total or unicompartmental arthroplasty may be considered. However, there are limited studies analyzing outcomes of unicompartmental knee arthroplasties (UKAs) for osteonecrosis involving an isolated compartment of the knee. The aims of this study were to analyze outcomes of UKAs for osteonecrosis with specific focus on 1) survivorship free of any revision or reoperation, 2) risk factors for failure, 3) clinical outcomes, and 4) complications. Patients and Methods: A total of 45 patients underwent 46 UKAs for knee osteonecrosis between 2002 and 2014 at our institution (The Mayo Clinic, Rochester, Minnesota). Twenty patients (44%) were female; the mean age of the patients was 66 years, and mean body mass index (BMI) was 31 kg/m2. Of the 46 UKAs, 44 (96%) were medial UKAs, and 35 (76%) were fixed-bearing design. Mean mechanical axis postoperatively was 1.5° varus (0° to 5° varus); 41 UKAs (89%) were performed for primary osteonecrosis. Mean follow-up was five years (2 to 12). Results: Survivorship free of any revision in the cohort was 89% (95% CI 77 to 99) and 76% (95% CI 53 to 99) at five and ten years, respectively. In patients undergoing UKA for primary osteonecrosis survivorship free of any revision was 93% (95% CI 83 to 100)at both five and ten years. Secondary osteonecrosis was a significant risk factor for poorer survivorship free of any revision or reoperation (hazard ratio 7.7, p = 0.03). Three medial UKAs (6.5%) were converted to total knee arthroplasties (TKAs): two for lateral compartment degeneration and one for development of lateral osteonecrosis. No implants were revised for loosening, fracture, or wear. Knee Society scores improved from a mean of 60 (44 to 72) preoperatively to a mean of 94 postoperatively (82 to 100) (p < 0.001). There were no surgical complications. Conclusion: When done for primary osteonecrosis of the knee, UKA resulted in reliable clinical improvement, minimal complications, and durable estimated implant survivorship free of revision at ten years. UKA done for secondary osteonecrosis was substantially less durable at mid-term follow-up. Progression of knee degeneration, rather than implant failure or loosening, was most common indication for conversion to TKA. Cite this article: Bone Joint J 2018;100-B:450-4.

A randomized controlled trial of fixed- versus mobile-bearing total knee arthroplasty: a follow-up at a mean of ten years.

Aims: It has been suggested that mobile-bearing total knee arthroplasty (TKA) might lead to better outcomes by accommodating some femorotibial rotational mismatch, thereby reducing contact stresses and polyethylene wear. The aim of this study was to determine whether there is a difference between fixed- and mobile-bearing versions of a contemporary TKA with respect to durability, range of movement (ROM) and function, ten years postoperatively. Patients and Methods: A total of 240 patients who were enrolled in this randomized controlled trial (RCT) underwent a primary cemented TKA with one of three tibial components (all-polyethylene fixed-bearing, modular metal-backed fixed-bearing and mobile-bearing). Patients were reviewed at a median follow-up of ten years (IQR 9.2 to 10.4). Results: There was no difference in durability, as measured by survivorship free of revision for any reason, nor in mean maximal ROM at ten years (p = 0.8). There was also no difference in function, as measured by Knee Society (KS) function scores (p = 0.63) or the prevalence of patellar tilt (p = 0.12). Conclusion: In this clinical RCT, the mobile-bearing design of TKA was found to be reliable and durable, but did not provide better maximum knee flexion, function or durability ten years postoperatively compared with a posterior-stabilized, fixed-bearing design incorporating either an all-polyethylene or a modular-metal-backed tibial component. Cite this article: Bone Joint J 2018;100-B:925-9.

Neutral mechanical alignment: Is it Necessary?

The cause of dissatisfaction following total knee arthroplasty (TKA) remains elusive. Much attention has been focused on static mechanical alignment as a basis for surgical success and optimising outcomes. More recently, research on both normal and osteoarthritic knees, as well as kinematically aligned TKAs, has suggested that other specific and dynamic factors may be more important than a generic target of 0 ± 3º of a neutral axis. Consideration of these other variables is necessary to understand ideal targets and move beyond generic results.

Greater inadvertent muscle damage in direct anterior approach when compared with the direct superior approach for total hip arthroplasty.

AIMS: We wished to quantify the extent of soft-tissue damage sustained during minimally invasive total hip arthroplasty through the direct anterior (DA) and direct superior (DS) approaches. MATERIALS AND METHODS: In eight cadavers, the DA approach was performed on one side, and the DS approach on the other, a single brand of uncemented hip prosthesis was implanted by two surgeons, considered expert in their surgical approaches. Subsequent reflection of the gluteus maximus allowed the extent of muscle and tendon damage to be measured and the percentage damage to each anatomical structure to be calculated. RESULTS: The DA approach caused substantially greater damage to the gluteus minimus muscle and tendon when compared with the DS approach (t-test, p = 0.049 and 0.003, respectively). The tensor fascia lata and rectus femoris muscles were damaged only in the DA approach. There was no difference in the amount of damage to the gluteus medius muscle and tendon, piriformis tendon, obturator internus tendon, obturator externus tendon or quadratus femoris muscle between approaches. The posterior soft-tissue releases of the DA approach damaged the gluteus minimus muscle and tendon, piriformis tendon and obturator internus tendon. CONCLUSION: The DS approach caused less soft-tissue damage than the DA approach. However the clinical relevance is unknown. Further clinical outcome studies, radiographic evaluation of component position, gait analyses and serum biomarker levels are necessary to evaluate and corroborate the safety and efficacy of the DS approach. Cite this article: Bone Joint J 2016;98-B1036-42.

Poor outcomes of isolated tibial insert exchange and arthrolysis for the management of stiffness following total knee arthroplasty.

BACKGROUND: Severe stiffness after total knee arthroplasty is a debilitating problem. In patients with securely fixed and appropriately aligned components, arthrolysis of adhesions and exchange to a thinner tibial polyethylene insert may appear to be a reasonable and logical solution. We reviewed our experience with this procedure to determine its efficacy. METHODS: From 1992 through 1998, seven knees with marked stiffness after total knee arthroplasty were treated at our institution with arthrolysis of adhesions and conversion to a thinner tibial polyethylene insert. Only patients in whom the total knee prosthesis was well aligned, well fixed, and not associated with infection were included. There were five women and two men with a mean age at revision of sixty-one years (range, thirty-eight to seventy-four years). The average time to revision was twelve months, and the mean arc of motion prior to revision was 38.6 degrees (range, 15 degrees to 60 degrees ). The duration of follow-up after the insert exchange averaged 4.2 years (range, two to eight years). RESULTS: Mean Knee Society pain and function scores changed from 44 and 36.4 points preoperatively to 39.6 and 46 points at the time of final follow-up. Two knees were rerevised, one because of infection and the other because of aseptic loosening of the components. The five remaining knees were painful and stiff at the time of final follow-up. Four of these five knees were severely painful, and one knee was moderately and occasionally painful. The mean arc of motion of these five knees was 58 degrees (range, 40 degrees to 70 degrees ) at the time of final follow-up. CONCLUSION: Isolated tibial insert exchange, arthrolysis, and débridement failed to provide a viable solution to the difficult and poorly understood problem of knee stiffness in a group of carefully selected patients following total knee arthroplasty. We therefore have little enthusiasm for the continued use of this strategy.

Role of the posterior cruciate ligament in total knee arthroplasty.

Since the introduction of condylar knee designs, total knee arthroplasty has become a remarkably successful and durable procedure. Improvements in instrumentation systems, fixation, and patellar resurfacing have been widely applied and have made total knee arthroplasty a reproducible procedure. The appropriate role for the posterior cruciate ligament in total knee arthroplasty, however, continues to be debated. Proponents of both cruciate substitution and cruciate retention can point to excellent clinical and radiographic results in the literature with knee designs of both types. Recent research findings in the areas of biomechanics, histology, and gait analysis, combined with refinements in intraoperative technique, have further sharpened the focus of the posterior cruciate ligament debate.

Minimising blood loss and transfusion in contemporary hip and knee arthroplasty.

Despite advances in contemporary hip and knee arthroplasty, blood loss continues to be an issue. Though blood transfusion has long been used to treat post-operative anemia, the associated risks are well established. The objective of this article is to present two practical and effective approaches to minimising blood loss and transfusion rates in hip and knee arthroplasty: the use of antifibrinolytic medications such as tranexamic acid and the adoption of more conservative transfusion indications.

Varus tibial joint line obliquity: a potential cause of femoral component malrotation.

In 60 consecutive total knee arthroplasties done in 52 patients with primary osteoarthritis and varus or neutral tibiofemoral alignment, the posterior condylar angle was calculated intraoperatively and averaged 3.98 degrees (range, 0 degrees-9 degrees). Eighteen knees had a posterior condylar angle value less than 3 degrees whereas 27 knees had a posterior condylar angle value of 5 degrees or greater. Final rotational alignment of the femoral component was set parallel to the transepicondylar axis. Only one of these 60 knees required a lateral retinacular release for proper patellar tracking during the knee arthroplasty. When compared with three previously defined angles measured on the radiographs taken preoperatively, only the tibial plateau-tibial shaft angle values were correlated significantly with the value of the posterior condylar angle. As the tibial varus joint line obliquity increased, there was a distinct tendency for the transepicondylar axis to be rotated more externally relative to the posterior condylar axis. This variance suggests that the use of the posterior condylar axis as a rotational reference is inappropriate in many knees with arthritis with varus or neutral tibiofemoral alignment. In particular, varus tibial joint line obliquity of more than 4 degrees increases the likelihood of femoral component malrotation when the posterior femoral condyles are used to reference femoral component rotation.

Asymmetric patella resurfacing in total knee arthroplasty.

Three hundred consecutive primary, cemented, condylar total knee arthroplasties (TKAs) were reviewed for the presence of asymmetric patella resurfacing using a postoperative Merchant or sunrise patellar radiograph. Twenty-one knees in 14 patients were found to have the patella asymmetrically resurfaced. Asymmetric resurfacing typically involved the inadvertent preferential resurfacing of the lateral facet with underresection of bone from the medial patellar facet. All patients underwent follow-up for a minimum of 5 years, with a mean follow-up of 7.5 years. Of the 21 knees, 3 revisions were required for patellar complications. One patellar component was loose on radiographs and there was marked patellofemoral pain in 6 knees. Overall, 11 of 21 knees (52%) underwent revision or were recommended for revision for patellar complications or had anterior knee pain that limited activities. Inadvertent asymmetric patella resurfacing using the kinematic condylar implant adversely affects the outcome after TKA.

Outcome after reinfection following reimplantation hip arthroplasty.

Between 1976 and 1992, reinfection developed in 34 patients treated for an infected total hip arthroplasty with removal of the prosthesis and implantation of another prosthesis. These patients included 15 men and 19 women with a mean age of 62 years. Infection recurred an average of 2.2 years after reimplantation of the new prosthesis. Followup after the diagnosis of reinfection averaged 5.1 years. Reinfection after an attempt at reimplantation total hip arthroplasty was seldom compatible with a good functional outcome. Resection arthroplasty was reliable in eradicating reinfection but led to poor function and was associated with persistent pain. Although reimplantation of a third prosthesis allowed 3 patients to achieve an excellent result, the 8 hips that failed a third reimplantation attempt had the worst functional results in this study. The results from the present series suggest that reinfection after an attempt at reimplantation is a contraindication to further attempts at a 1-stage reimplantation of another prosthesis. Those patients in whom the same single microorganism has been identified from the failed primary total hip and from the failed first reimplantation, however, may be reasonable candidates for an attempt at a 2-stage reimplantation of a third prosthesis, particularly when a deficiency in prior antibiotic therapy or surgical technique can be identified.

Patellar component resection in revision and reimplantation total knee arthroplasty.

Between 1979 and 1995, 34 knees in 31 patients had a revision or reimplantation total knee arthroplasty in which the patellar component could not be reinserted. The patellar bone stock in each of those cases was compromised markedly and precluded adequate prosthetic fixation. The mean followup after the revision operation was 3.5 years (range, 2-14 years). The Knee Society knee score improved from a mean of 59 points preoperatively to a mean of 75 points postoperatively. The function score improved from a mean of 46 points preoperatively to a mean of 69 points postoperatively. Complications occurred in five patients: one patient sustained a patellar fracture that required no additional treatment; one experienced intermittent episodes of patellar subluxation; one had a recurvatum deformity develop and was treated with a brace; one had persistent knee stiffness and had four manipulations; and one patient had an extensor lag of 30 degrees develop. Twenty-six patients were satisfied with the results of their revision operations and five were dissatisfied. Ten patients had persistent knee symptoms referable to the patellofemoral articulation: mild pain in three; moderate pain in six; and severe pain in one. This study suggests that resection of the patellar component during revision or reimplantation total knee arthroplasty may be a reasonable approach for patients with markedly compromised patellar bone stock; however, mild or moderate anterior knee pain can be expected to persist in as much as 1/3 of these patients.

Tibial wedge augmentation for bone deficiency in total knee arthroplasty. A followup study.

This report constitutes a followup of a previous study of 28 knees in 25 patients with metal wedge augmentation for tibial bone deficiency. Those patients were reviewed 2.3 years after surgery; 79% had excellent results, and 21% had good results. Twenty-four knees in 21 patients with a metal wedge augmentation for tibial bone deficiency were reviewed 5.6 years clinically and 4.8 years radiographically after surgery. Clinical results were excellent in 67%, good in 29%, and poor in 4%. The only poor result was in 1 knee that required 2 revision procedures: the first for failure of a metal-backed patellar component and the second for aseptic loosening of the femoral component. Radiolucent lines at the cement bone interface beneath the metal wedge were present in 13 knees. Eleven of those radiolucencies were < 1 mm in width, and 2 were 1 to 3 mm in width. None of those lucent lines were progressive. Metal wedge augmentation for tibial bone deficiency is a useful option. No deterioration of the wedge-prosthesis or wedge-cement-bone interface was seen at midterm followup.

Total knee arthroplasty after ipsilateral peripheral arterial bypass graft: acute arterial occlusion is a risk with or without tourniquet use.

A retrospective review was done of the total joint registry at the Mayo Clinic, Rochester, Minnesota, which contains the computerized records of 19,808 consecutive total knee arthroplasties (TKAs) including primary and revision that were performed from 1970 to 1997. From that database, 9 patients were found to have had a TKA after an ipsilateral peripheral arterial reconstruction. One patient had had bilateral peripheral arterial reconstruction followed by bilateral TKA, and 10 TKAs were reviewed. The medical records were reviewed retrospectively with particular attention given to the type of peripheral bypass surgery performed, the bypass graft source, the timing of the bypass surgery relative to TKA, the use of a tourniquet at the time of TKA, and the occurrence of complications after TKA. Of the 10 TKAs, 2 patients had acute arterial occlusion. One patient had a tourniquet, and the other patient did not. There was not a statistical correlation between graft type, tourniquet use, timing of surgery, postoperative anticoagulation, and occurrence of arterial occlusion. There is a marked risk of acute thrombosis of an ipsilateral arterial bypass graft after TKA that cannot be eliminated by performing the TKA without a tourniquet. Careful monitoring of the vascular status of the limb is required in the early postoperative period to detect arterial compromise. Should limb ischemia be suspected, an emergent vascular surgery consultation is required, and arterial flow to the lower extremity must be re-established.

Cemented all polyethylene tibial components in patients age 75 years and older.

Between 1976 and 1980, 81 knees in 59 patients 75 years of age or older, underwent primary total knee arthroplasty with a cemented, condylar femoral component and a cemented, moderately conforming, all polyethylene tibial component. All patients were followed up until death, revision surgery, or for a minimum of 10 years. Mean clinical followup was 8.1 years for the entire group and 14.6 years for those patients still alive. At final followup one patient (one knee) required revision surgery (for medial instability), and one patient (one knee) had marked pain but no radiographic evidence of loosening. No patients required revision surgery for aseptic loosening and no patients had symptomatic aseptic loosening at last followup. The mean Knee Society knee and function scores were 78 and 64 points, respectively at last followup. The mean postoperative range of motion was 101 degrees. The Kaplan-Meier survival of the index total knee arthroplasty at 14 years was 100% with symptomatic aseptic loosening as the end point; and 98% with revision for any cause as the end point. Cemented all polyethylene tibial components with a moderately conforming tibiofemoral articulation implanted in patients older than 75 years of age showed a high rate of survivorship without the need for revision surgery and without symptomatic loosening.