Long-Term Clinical Performance of an Uncemented, Mobile Bearing, Anterior Stabilized Knee System and the Impact of Previous Knee Surgery.

BACKGROUND: The aim of this study is to report long-term survival and patient-reported outcome measures (PROMs) of the uncemented low contact stress total knee system and explore the potential association between prior knee surgery and outcomes. METHODS: A total of 1,289 procedures in 1,068 patients performed between 2000 and 2010 (mean follow-up 11.1 years) were retrospectively identified. All patients received an uncemented, mobile bearing, anterior stabilized (cruciate sacrificing) knee implant with a porous coating on the bone-prosthesis surface. Implant survival was calculated using competing risk analyses at 5, 10, and 15 years. PROMs include the Oxford Knee Score, Knee Society Score (domain function), EuroQol 5D-3L, and Numeric Rating Scale for pain during rest and activity, and for overall satisfaction. The association between previous surgery (no surgery versus meniscectomy versus arthroscopy versus corrective osteotomies) and implant survival was assessed with multivariable Cox proportional hazards analysis; the association with PROMs was assessed with multivariable linear regression analyses. RESULTS: Survival after 5, 10, and 15 years was 97.0% (95% CI 96.0-98.0), 96.3% (95% CI 95.3-97.3), and 96.0% (95% CI 94.8-97.2), respectively. The most common reason for revision was aseptic loosening of the tibial tray (23/49 revisions, 47%). All PROMs were comparable with the reference values of the Dutch Arthroplasty Register. History of knee surgery prior to TKA was not associated with survival or PROMs. CONCLUSION: The low contact stress uncemented mobile bearing knee implant provides excellent survival and patient satisfaction in our cohort. Previous surgery does not seem to compromise results in our population.

Eighteen-Year Outcome of an Uncemented "Meniscal Bearing", Cruciate-Retaining Total Knee System.

BACKGROUND: The aim of this study is to evaluate the survival, radiographic, and functional outcomes of the uncemented "meniscal bearing" cruciate-retaining Low Contact Stress (LCS) (DePuy Synthes, Warsaw, IN, USA) total knee system after a long-term follow-up period. METHODS: A total of 56 patients (67 knees) who received an uncemented "meniscal bearing" cruciate-retaining LCS total knee system between 2000 and 2005 were retrospectively reviewed. Patients were 64 ± 7 years old with osteoarthritis as the indication for arthroplasty. The survivorship, radiographs, and patient-reported outcome measures (PROMs) were analyzed. RESULTS: The all-cause survival after 5, 10, 15, and 18 years was 97.0%, 93.8%, 92.0%, and 92.0%, respectively. Survival with revision for aseptic loosening as an end point was 98.4% at 5 years and 96.7% at 10, 15, and 18 years. Reasons of revisions and their interventions consisted of anterior knee pain requiring secondary patellar resurfacing (n = 3, 60%), polyethylene wear requiring an insert exchange (n = 2, 40%), and bearing spin-out requiring an insert exchange (n = 1, 20%). Two of the 5 revision cases developed aseptic loosening of the tibial component later on during the study period. A radiographic analysis demonstrated radiolucent lines in 14/47 implants (30%) after 12.0 ± 3.8 years, but were not revised, respectively. After a mean follow-up of 18.5 years, PROMs (n = 20) were found comparable with the 1-year postoperative PROMs of all implants reported by the LROI (Dutch Arthroplasty Register). CONCLUSION: This present study demonstrates good results of the uncemented "meniscal bearing" cruciate-retaining LCS total knee system toward survival and functional outcomes after a long-term median follow-up of 17.5 years. LEVEL OF EVIDENCE: Therapeutic retrospective cohort study, LEVEL III.

Evaluation of the 'Spaarne soft tissue procedure' as a treatment for recurrent patellar dislocations: a four-in-one technique.

PURPOSE: The 'Spaarne soft tissue procedure', is a 4-in-1 soft tissue procedure that treats recurrent patellar dislocations in the young and active population. The procedure has not yet described elsewhere. The purpose of this study is to analyse the redislocation rate and to evaluate the postoperative knee function and patient satisfaction. METHODS: Twenty-seven patients (34 knees) underwent the four-in-one SST-procedure. The 4-step technique required a minor change in 2010, including the use of a smaller strip of the patellar tendon for transposition. After a median follow-up of 10.4 years, the redislocation rate was evaluated as the primary outcome measure. Secondary outcome measures were functional outcome (IKDC, Kujala, Lysholm and Tegner activity scale) and Numeric Rating Scales for satisfaction and pain. RESULTS: Redislocation occurred in 8 cases (23.5%) and subluxation occurred in 13 cases (38.2%) post-surgery. A significant higher number of redislocations and subluxations were seen before 2010 (p = 0.04, p = 0.03). The median postoperative IKDC, Lysholm and Kujala scores for the total group were 54, 76 and 81 respectively. Pre- and postoperative Tegner activity scale were both level 3. Median NRS scores during rest, walking and sports were 1, 3 and 5 respectively. Satisfaction with the procedure was reported as 'excellent' or 'good' by 79% of the patients. CONCLUSION: Despite the high overall redislocation rate and increased pain scores, the SST-procedure shows to be a safe procedure in patients with recurrent patellar dislocations based on the cases after 2010. Mid- and long-term results show moderate to good functional outcomes and satisfaction. LEVEL OF EVIDENCE: Therapeutic retrospective cohort study, LEVEL III.

Autosomal dominant type I osteopetrosis is related with iatrogenic fractures in arthroplasty.

Autosomal dominant osteopetrosis (ADO) is a sclerotic bone disorder due to failure of osteoclasts. ADO poses difficulties during arthroplasty because of the increased chance for iatrogenic fractures due to sclerotic bone. ADO is divided into two types based on radiological findings, fracture risk, and osteoclast activity. These differences suggest less brittle bone in patients with ADO I compared to that of patients with ADO II, which suggests a smaller chance of preoperative fractures during cementless arthroplasty in ADO I compared with that in ADO II. A case of cementless total knee arthroplasty in a patient with ADO I is presented. Total hip arthroplasty was performed during follow-up, and known major problems related to ADO II were experienced. Therefore, the differences between ADO I and ADO II may not be clinically relevant for an iatrogenic fracture during arthroplasty in patients with ADO.

Tibial tubercle osteotomy with absorbable suture fixation in revision total knee arthroplasty: a report of 23 cases.

OBJECTIVE: Tibial tubercle osteotomy (TTO) is a well-known technique for improving exposure in difficult total knee arthroplasty (TKA). We have performed 23 revision TKAs with TTO. The tibial tubercle was fixated with only absorbable sutures afterwards. The aim of this study is to report on the clinical results and complications of this procedure. METHODS: We retrospectively evaluated 23 patients (mean age 69.6 years, range 43-84 years) who underwent TTO with only absorbable suture fixation. Clinic charts were reviewed to identify any complications that occurred. Obvious proximal migration and union of the tibial tubercle was evaluated on the postoperative radiographs. Knee Society scores and SF-36 were assigned at latest follow-up. RESULTS: The mean follow-up was 16.1 months (1-43). Two patients died of causes unrelated to surgery. In one case a fracture of the TTO occurred. No obvious migration of the osteotomy was detected. In two cases there was partial consolidation of the osteotomy, but without clinical consequences of pain or extension lag. In five patients a tibial plateau fracture occurred intraoperative which allowed partial weight bearing during 6 weeks. These fractures were not related to the surgical technique of the TTO. In 15 out of 23 patients a Knee Society Score could be assigned. The mean total knee score (maximum 200 points) after revision was 99.5 (17-166) (clinical KSS 52.1, functional KSS 47.3) at latest follow-up. SF-36 scores could be assigned to 16 patients; the mean SF-36 (maximum 100) was 88 (range 74-98). CONCLUSION: Tibial tubercle osteotomy with only absorbable suture fixation is a reliable and simple method of fixation and provides adequate stability. It is a straightforward surgical technique which is less time-consuming and expensive compared with screw and cerclage wire fixation and no hardware removal will be necessary. Therefore, this method is a beneficial technique for the enhancement of surgical exposure in difficult revision TKA.

Case report: Painless chronic liner dissociation of a total hip arthroplasty.

BACKGROUND: Dislocation or liner dissociation of a total hip prosthesis usually results in pain and discomfort. Although several reports describe chronic dislocation and its treatment, chronic liner dissociation is an unreported complication. CASE DESCRIPTION: We report an unrecognized dissociation and displacement of the liner of a total hip prosthesis after revision THA. The patient had virtually no pain or functional restrictions. The patient's only complaint was pain on the contralateral side, associated with a leg-length discrepancy. Since the patient had no complaints relative to the liner dissociation we elected not to pursue further treatment. The contralateral pain was treated successfully with a shoe lift. LITERATURE REVIEW: Chronic dislocation of a THA is a rare complication and we found reports of only seven cases in the literature. We found no reports of chronic liner dissociation. CLINICAL RELEVANCE: Orthopaedic surgeons should be aware of the possibility of this rare complication. Our case and the literature suggest treatment can be nonsurgical or surgical.