Alfredo Schiavone Panni

Minor varus alignment provides better results than neutral alignment in medial UKA.

INTRODUCTIONnFew data exist regarding the outcome and survivorship of medial UKA in patients with minor varus alignment. The purpose of this study was therefore to analyse the clinical results of medial UKA implanted with no more than 7° of varus, and to verify whether there was a relationship between limb alignment and overall outcomes.nnnMATERIAL AND METHODSnOne hundred and twenty five medial fixed-bearing UKAs with no more than 7° of varus were retrospectively analysed. The varus/valgus inclination and thickness of the bone cuts were performed relating to the proximal tibial epiphyseal axis. Patients were assessed with the IKS scores and range of knee motion. The subjects were classified into three groups according to the postoperative femoro-tibial mechanical alignment angle (group A: -2° to 1°; group B: 2° to 4°; group C: 5° to 7°).nnnRESULTSnThe mean follow-up was 7.6years (range, 3.5-9.3). IKS knee scores increased proportionally with increasing varus according to a linear relationship (p≪0.01). Additionally, IKS knee scores were significantly higher in group B and still higher in group C if compared to those in group A (p=0.003). Finally, a significantly higher frequency of IKS function scores>90 points in subjects with femoro-tibial mechanical alignment angle≥4° was found (p=0.009).nnnCONCLUSIONSnMinor varus alignment does not compromise the mid- to long-term outcome of a medial UKA, and gives better results compared to neutral or close-to-neutral alignment.nnnLEVEL OF EVIDENCEnIV - Retrospective case series study.

Modular augmentation in revision total knee arthroplasty

PurposeControversy exists about the real effectiveness of modular augmentation to manage bone defects in revision total knee arthroplasty. The purpose of this study was to determine whether use of modular augmentation to reconstruct severe defects (1) significantly increased overall outcomes, (2) caused radiolucency or osteolysis and (3) affected mid-term survivorship of knee revisions. The hypothesis was that modular augmentation provides a good survivorship of knee revisions.MethodsThirty-eight consecutive revision knee arthroplasties were followed for a median follow-up period of 7 (4.5–9)xa0years. Type 2 and 3 defects were treated with metal augments, tantalum cones and modular cementless stems. Patients were assessed using the IKS knee and function scores and the HSS score.ResultsThe median IKS knee and function scores and HSS score were 34 (15–58), 19.5 (13–39) and 30 (24–60) points before the operation, respectively, and 78 (49–97), 76 (58–90) and 80.5 (64–98) points (pxa0<xa00.001) at the latest follow-up. The median knee flexion increased from 82° (31°–110°) to 116° (100°–129°) (pxa0<xa00.01). Tibial radiolucencies were observed in 2 (5.2xa0%) cases. Re-revision was necessary in three (7.9xa0%) patients.ConclusionsModular augmentation may reduce the need for allografting to treat severe bone defects, providing a well-functioning and durable knee joint reconstruction.Level of evidenceCase-series study, Level IV.

Acute patellar dislocation. What to do

Acute patellar dislocation is a common knee injury that occurs most often in adolescents, frequently associated with sporting and physical activities. Patellar re-dislocation after the first episode appears to depend primarily on the medial patellofemoral ligament injury which represents the primary ligamentous restraint, providing about 50–60xa0% of the restraining force against lateral patellar displacement. Clinically, up to 94–100xa0% of patients suffer from medial patellofemoral ligament rupture after first-time patellar dislocation. Controversy regarding how patients with first patellar dislocation should be managed still exists. Though most authors have reported good results with the conservative treatment after a first-time dislocation, several circumstances may warrant surgical intervention. A surgical approach would be necessary in the presence of severe cartilage damage or a relevant disruption of the medial stabilizers with subluxation of the patella. In these cases, the repair/reconstruction of medial stabilizers should follow the treatment of the chondral injury. Medial patellofemoral ligament reconstruction may be a more reliable method of stabilizing the patella than its repair, which has limitations related to the medial patellofemoral ligament injury location. Nowadays, there is no evidence available where osseous abnormalities should be addressed in addition to restoring the medial patellofemoral ligament.

Wound complications in total knee arthroplasty. Which flap is to be used? With or without retention of prosthesis?

PurposeThe aim of our review paper is to present a possible algorithm of treatment of knee periprosthetic soft tissue defects, relative to their extent and depth. Different management of exposed total joints is also proposed, depending on the presence or loss of deep infection and on the timing of infection itself.MethodsIn accordance with literature and the experience of senior knee surgeon, the incidence and risk factors, and possible treatment options of wound complications following total knee arthroplasty have been throughly analyzed.ResultsThere is much controversy regarding the optimal management of wound necrosis around a total knee. Local wound care, debridement, and fasciocutaneous, muscle and perforator flaps have been differently used. Muscle coverage remains the standard to which all other flaps should be compared, especially in infected wounds. Perforator flaps have recently represented a true revolution in the soft tissue reconstruction around the knee, with peculiar advantages due to their low donor morbidity and long pedicles.ConclusionWhen wound complications occur, prompt management is mandatory. An algorithm for treatment of wound defects is presented, available for both primary and revision knee replacement.

Constraint choice in revision knee arthroplasty

PurposeAlong with the increase in primary total knee arthroplasty, there has been an increase in the number of revisions. The aim of this study was to propose a selection algorithm for the knee revision constraint according to the state of ligaments and to the bone defects Anderson Orthopaedic Research Institute Classification [AORI] classification. The hypothesis was that this algorithm would facilitate the appropriate choice of prosthesis constraint, thus providing stable components and a good long-term survivorship of the knee revisions.MethodsSixty consecutive revision knee arthroplasties in 57 patients were prospectively evaluated. Prostheses implanted at revision included postero-stabilised, condylar constrained and rotating hinged, relative to the state of the ligaments and of the bone loss around the knee. The median follow-up was nine years (range, 4–12).ResultsThe median IKS knee and function scores and HSS score were 41 (15–62), 21.5 (12–43) and 34 (23–65) points, respectively, before the operation, and 81 (48–97), 79 (56–92) and 83.5 (62–98) points (pu2009<u20090.001) at the latest follow-up evaluation. The median ROM increased from 74° (29–110°) preoperatively to 121° (98–132°) (pu2009<u20090.01) at the final follow-up. Re-revision was necessary in five (8.3xa0%) patients.ConclusionsA selection algorithm for the revision implant constraint based on the state of ligaments and the bone loss AORI classification could provide stable knee reconstructions and long-term success of knee revisions.

Unicompartmental knee replacement provides early clinical and functional improvement stabilizing over time

PurposeUnicompartmental knee replacement preserves uninvolved osteocartilaginous and soft tissue structures, thereby allowing a more physiological and early clinical and functional recovery. The aim of this study was to report the results of ZUK unicompartmental fixed metal-back prosthesis and how these results change over time.MethodsBetween 2005 and 2007, 80 ZUK prostheses were implanted in 80 patients for unicompartmental osteoarthritis or osteonecrosis. Patients were clinically assessed using the International Knee Society scores. Postoperative values of mechanical axis were calculated 12xa0months after surgery and compared to the preoperative ones.ResultsThe mean International Knee Society knee and function scores improved, respectively, from 46xa0±xa09 and 54xa0±xa08 preoperatively to 82xa0±xa05 and 94xa0±xa03 at the last follow-up (Pxa0<xa00.001). Average flexion increased from 110°xa0±xa09° to 127°xa0±xa08° (Pxa0<xa00.01). Patients with unicompartmental knee reached good clinical outcome very early and remained at the same level. Age did not significantly influence clinical and functional scores.ConclusionsHigh success rates of the modern unicompartmental knee implants depend on the materials and design evolution, improvement of the surgical technique, and the strong restriction of indications.Level of evidenceProspective non-randomized case-series study, Level IV.

Unicompartmental knee arthroplasty is effective: ten year results

PurposeUnicompartmental knee arthroplasty (UKA) presents low morbidity and complication risk and provides excellent outcomes and fast recovery. Despite these facts, knee-replacement registries have shown high failure rates for UKA, especially when compared with traditional TKA. The purpose of this study was therefore to report outcomes, complications, and ten year survivorship rate of medial ZUK unicompartmental knee prosthesis.MethodsWe retrospectively analysed 136 medial UKAs in 124 patients, with a maximum follow-up of tenxa0years. Patients were assessed through the International Knee Society (IKS) scores and range of motion (ROM). A complete X-ray study was performed in all patients. Limb alignment was assessed by measuring the femorotibial mechanical alignment. At surgery, bone resections were performed according to proximal tibial epiphyseal axis.ResultsMean IKS knee score improved from 45.7 (range 35–63) points preoperatively to 87.2 (range 71–100) points at the latest follow-up. Mean IKS function score improved from 50.9 (range 40–70) points to 89.1 (range 75–100) points (pu2009<u20090.05). Mean ROM increased from 106.1° (range 98–123°) to 128.6° (range 116–139°) (pu2009<u20090.01). Four cases (2.9xa0%) were revised due to failure for any cause, so that survivorship was 97.1xa0% at the latest follow-up.ConclusionsThis study demonstrates excellent outcomes and survivorship for the ZUK unicompartmental knee prosthesis. Based on our findings, we believe that the ZUK prosthesis offers an effective and durable solution for treating medial degeneration of the knee.Level of Evidence IV - Retrospective case series study

Bone loss following knee arthroplasty: potential treatment options

IntroductionThe management of bone loss is a crucial aspect of the revision knee arthroplasty. Bone loss can hinder the correct positioning and alignment of the prosthetic components, and can prevent the achievement of a stable bone–implant interface. There is still controversy regarding the optimal management of knee periprosthetic bone loss, especially in large defects for which structural grafts, metal or tantalum augments, tantalum cones, porous metaphyseal sleeves, and special prostheses have been advocated. The aim of this review was to analyze all possible causes of bone loss and the most advanced strategies for managing bony deficiency within the knee joint reconstruction.Materials and methodsMost significant and recent papers about the management of bone defects during revision knee arthroplasty were carefully analyzed and reviewed to report the most common causes of bone loss and the most effective strategies to manage them.ResultsModular metal and tantalum augmentation showed to provide more stable and durable knee revisions compared to allografts, limited by complications such as graft failure, fracture and resorption. Moreover, modular augmentation may considerably shorten operative times with a potential decrease of complications, above all infection which has been frequently associated to the use of allografts.ConclusionsModular augmentation may significantly reduce the need for allografting, whose complications appear to limit the long-term success of knee revisions.

Low-grade periprosthetic knee infection: diagnosis and management.

Diagnosis and management of low-grade periprosthetic knee infection are still controversial and debatable. The diagnosis of low-grade infection after total knee arthroplasty is often complex, as clinical symptomatology and diagnostic studies are highly conflicting and knees often exhibit well-fixed components. Although the criterion standard for staged reimplantation is interim placement of an antibiotic-loaded spacer, less-invasive surgical procedures have been advocated for managing infections caused by low-virulence bacteria. Debridement with polyethylene exchange and single-stage reimplantation could offer advantages, such as fewer surgeries, reduced potential for intraoperative complications, and lower direct social costs. The aim of this narrative review was to analyze the literature to evaluate the effectiveness of different surgical procedures in managing low-grade periprosthetic knee infections. Additionally, the most reliable investigations for diagnosing total knee infection caused by low-virulence bacteria were reviewed.Level of evidence Level V.

Prosthetic knee infection by resistant bacteria: the worst-case scenario.

AbstractPurposeThe aim of the present paper was to determine (1) the incidence of failure (defined as the persistence or the recurrence of the infection), (2) the incidence of prosthesis (or even limb) loss (defined as the final need for an arthrodesis, resection arthroplasty or amputation) and (3) what factors could influence the failure in patients treated with a two-stage reimplantation for periprosthetic knee infections caused by resistant bacteria.nMethodsThe authors retrospectively reviewed 29 total knee arthroplasties infected by resistant bacteria in 29 patients who underwent a two-stage revision. Between the stages, intravenous-targeted antibiotics were administered for a median period of 8 (range 6–12) weeks. Median follow-up was 10 (range 7–14) years.nResultsThe authors found that failure occurred in 5 of 29 patients (17.2xa0%). When methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative staphylococci (MR-CoNS) were involved, failure rate was 10xa0% (2 of 20). When vancomycin-resistant enterococcus (VRE), multidrug-resistant (MDR) Acinetobacter baumannii and MDR Pseudomonas aeruginosa were involved, the failure rate was 33.3xa0% (3 of 9). Of those five patients, two underwent amputations, one chronic suppressive antibiotic therapy, one arthrodesis and one resection arthroplasty; among them, three lost the limb (10.3xa0% of the overall group). Timing of reimplantation and patient comorbidities did not significantly influence the failure.ConclusionsTwo-stage protocol resulted in a viable option for patients with infections by some resistant organisms (MRSA and MR-CoNS). However, when highly resistant organisms were involved (VRE, MDR Acinetobacter Baumannii and MDR Pseudomonas aeruginosa), the failure rate was much higher. In all cases of failure of the two-stage reimplantation, prosthesis (or even limb) loss occurred. Consequently, patients should be counselled that when highly resistant bacteria are involved, two-stage reimplantation could not be successful, with high final risk of prosthesis (or even limb) loss.Level of evidenceRetrospective case series, Level IV.