Cadera / Hip: cada milímetro cuenta

Restoration of the Hip Center During THA Performed for Protrusio Acetabuli Is Associated With Better Implant Survival
Yaser M. K. Baghdadi MD, A. Noelle Larson MD, Rafael J. Sierra MD
Clin Orthop Relat Res (2013) 471:3251–3259
DOI 10.1007/s11999-013-3072-x

Abstract

Background
Acetabular protrusio is an uncommon finding in hip arthritis. Several reconstructive approaches have been used; however the best approach remains undefined. Questions/purposes Our purposes in this study were to (1) describe the THA survivorship for protrusio as a function of the acetabular component, (2) evaluate survi- vorship of the cup as a function of restoration of radiographic hip mechanics and offset, and (3) report the long-term clinical results.

Methods
One hundred twenty-seven patients (162 hips) undergoing primary THA with acetabular protrusio were retrospectively reviewed. The mean age of the patients at surgery was 66 ± 13 years, and the mean followup was 10 ± 6 years (range, 2–25 years).The cup fixation was uncemented in 107 (83 with bone graft) and cemented in 55 hips (14 with bone graft). Preoperative and postoperative radiographs were reviewed for restoration of hip mechanics and offset.

Results
The THA survival from aseptic cup revision at 15 years was 89% (95% CI, 75%–96%) for uncemented compared with 85% (95% CI, 68%–94%) for cemented cups. The risk of aseptic cup revision significantly increased by 24% (hazards ratio, 1.24; 95% CI, 1.02–1.5) for every 1 mm medial or lateral distance away from the native hip center of rotation to the prosthetic head center. Harris hip scores were improved by mean of 27 ± 20 points (n = 123) with a higher postoperative score for uncemented bone grafted compared with solely cemented cups (81 ± 16 versus 71 ± 20 points).

Conclusions
Restoring hip center of rotation using an uncemented cup with or without bone graft was associated with increased durability in our series. There was a 24% increase in the risk of aseptic cup revision for every 1 mm medial or lateral distance away from the native hip center to the prosthetic head center.

Level of Evidence
Level III, therapeutic study

Rodilla/Knee: Sin diferencias de riesgo de revisión con distintos polietilenos

Is There a Difference in Total Knee Arthroplasty Risk of Revision in Highly Crosslinked versus Conventional Polyethylene?

Paxton EW, Inacio MC, Kurtz S, Love R, Cafri G, Namba RS.

Clin Orthop Relat Res. 2015 Jan 8. [Epub ahead of print]

Abstract

BACKGROUND: 

Highly crosslinked polyethylene (HXLPE) was introduced to reduce wear and associated osteolysis in total knee arthroplasty (TKA). However, there is limited clinical evidence that HXLPE is more effective than conventional polyethylene (CPE) in TKA.

QUESTIONS/PURPOSES: 

(1) Do primary TKAs with HXLPE tibial inserts have a lower risk of revision (all-cause, aseptic, and septic) than TKAs with CPE tibial inserts? (2) In NexGen TKA (Zimmer Inc, Warsaw, IN, USA) bearings, do HXLPE tibial inserts have a lower risk of revision (all-cause, aseptic, and septic) than CPE tibial inserts? (3) In Press-Fit Condylar TKA (PFC or PFC Sigma; DePuy Inc, Warsaw, IN, USA), do HXLPE tibial inserts have a lower risk of revision (all-cause, aseptic, and septic) than procedures performed with CPE tibial inserts?

METHODS: 

The Kaiser Permanente Total Joint Replacement Registry was used to identify primary TKAs (N = 77,084) performed during the study period (April 2001 to December 2011) with cobalt-chromium alloy on CPE (CoCr-CPE) and CoCr-HXLPE bearings. The registry has 95% voluntary participation and less than 9% were loss to followup during the 10-year study period. A total of 60,841 (79%) had CoCr-CPE bearings, 11,048 (14%) had CoCr-HXLPE bearings, and 5195 (7%) were unknown. Specific knee implant designs (NexGen, Zimmer and PFC-Sigma, DePuy Inc) were also evaluated. These implants represented 41% (31,793) and 49% (37,457), respectively, of the 77,084 TKAs of known implant types registered during that period; implant selection was at the discretion of the attending surgeon. Descriptive statistics and marginal Cox regression models with propensity score adjustments were applied to compare risk of revision for CoCr-CPE versus CoCr-HXLPE TKA bearings.

RESULTS: 

At 5 years followup, cumulative incidence of revision for CoCr-CPE and CoCr-XLPE were 2.7% and 3.1%, respectively. Adjusted risks of all-cause (hazard ratio [HR], 1.05; 95% confidence interval [CI], 0.86-1.29; p = 0.620), aseptic (HR, 1.01; 95% CI, 0.77-1.32; p = 0.954), and septic revision (HR, 1.11; 95% CI, 0.81-1.51; p = 0.519) did not differ in patients with CoCr-XLPE bearings compared with CoCr-CPE. Within TKAs with NexGen components, the adjusted risks of all-cause (HR, 1.14; 95% CI, 0.86-1.51; p = 0.354), aseptic (HR, 1.14; 95% CI, 0.79-1.65; p = 0.493), and septic revision (HR, 1.14; 95% CI, 0.76-1.73; p = 518) were similar in patients with CoCr-XLPE compared with those with CoCr-CPE bearings. Finally, within the TKAs with PFC components, the adjusted risks of all-cause (HR, 0.80; 95% CI, 0.49-1.30; p = 0.369), aseptic (HR, 0.62; 95% CI, 0.62-1.14; p = 0.123), and septic revision (HR, 0.97; 95% CI, 0.51-1.85; p = 0.929) were also similar in patients with CoCr-XLPE compared with those with CoCr-CPE bearings.

CONCLUSIONS: 

In this large study, we did not find differences in risk of revision for CoCr-HXLPE compared with CoCr-CPE bearings at 5 years followup. In selecting HXLPE in TKA, clinicians should consider the increased cost and lack of available evidence of performance for greater than 10 years followup. Future studies are necessary to evaluate longitudinal outcomes of CoCr-HXLPE versus conventional TKA bearings.

LEVEL OF EVIDENCE: 

Level III, therapeutic study. 

Prótesis total articular / Total Joint Arthroplasty: ver las bacterias ocultas en el biofilm

Imaging bacteria and biofilms on hardware and periprosthetic tissue in orthopedic infections.

Nistico L, Hall-Stoodley L, Stoodley P

Methods Mol Biol. 2014;1147:105-26

Abstract

Infection is a major complication of total joint arthroplasty (TJA) surgery, and even though it is now as low as 1 % in some hospitals, the increasing number of primary surgeries translates to tens of thousands of revisions due to prosthetic joint infection (PJI). In many cases the only solution is revision surgery in which the hardware is removed. This process is extremely long and painful for patients and is a considerable financial burden for the health-care system. A significant proportion of the difficulties in diagnosis and treatment of PJI are associated with biofilm formation where bacteria attach to the surface of the prosthesis and periprosthetic tissue and build a 3-D biofilm community encased in an extracellular polymeric slime (EPS) matrix. Bacteria in biofilms have a low metabolic rate which is thought to be a major contributor to their recalcitrance to antibiotic treatment. The diagnosis of biofilm infections is difficult due to the fact that bacteria in biofilms are not readily cultured with standard clinical microbiology techniques. To identify and visualize in situ biofilm bacteria in orthopedic samples, we have developed protocols for the collection of samples in the operating room, for molecular fluorescent staining with 16S rRNA fluorescence in situ hybridization (FISH), and for imaging of samples using confocal laser scanning microscopy (CLSM). Direct imaging is the only method which can definitively identify biofilms on implants and complements both culture and culture-independent diagnostic methods.

Hombro/Shoulder: tenodesis para revisar la lesión SLAP

The Efficacy of Biceps Tenodesis in the Treatment of Failed Superior Labral Anterior Posterior Repairs.

Am J Sports Med. 2014 Feb 11

McCormick F1, Nwachukwu B, Solomon D, Dewing C, Golijanin P, Gross DJ, Provencher MT.

Abstract
BACKGROUND:The incidence and arthroscopic treatment of superior labral anterior posterior (SLAP) tears have increased over the past decade. Recent evidence has identified factors associated with poor outcomes, including age, overhead activity, and concomitant rotator cuff tears. Biceps tenodesis has also been suggested as an alternative treatment to repair. Moreover, there are no studies demonstrating effective treatment strategies for failed type II SLAP repairs.

PURPOSE:To prospectively evaluate the surgical outcomes of biceps tenodesis for patients who undergo elected revision surgery after an arthroscopically repaired type II SLAP tear. 

STUDY DESIGN:Case series; Level of evidence, 4.

METHODS:After institutional review board approval, 46 patients who met failure criteria for an arthroscopically repaired type II SLAP tear elected to undergo open subpectoral tenodesis by 2 fellowship-trained surgeons from 2006 to 2010 at a tertiary care military treatment facility. Objective outcomes were preoperative and postoperative assessments with the American Shoulder and Elbow Surgeons (ASES), Single Assessment Numeric Evaluation (SANE), and Western Ontario Shoulder Instability Index (WOSI) scores and an independent physical examination. Statistical analysis was performed via analysis of variance.

RESULTS:Of the 46 patients, 42 completed the study (91% follow-up rate). The mean age of the patients was 39.2 years, 85% were male, and the mean follow-up period was 3.5 years (range, 2.0-6.0 years). The rate of return to active duty and sports was 81%. There was a clinically and statistically significant improvement across all outcome assessments after revision surgery (preoperative mean scores: ASES = 68, SANE = 64, WOSI = 65; postoperative mean scores: ASES = 89, SANE = 84, WOSI = 81) (P < .0001) and shoulder range of motion (preoperative mean values: forward flexion = 135°, abduction = 125°; postoperative mean values: forward flexion = 155°, abduction = 155°) (P < .0001). There was 1 case of transient musculocutaneous nerve neurapraxia.

CONCLUSION:Biceps tenodesis is a predictable, safe, and effective treatment for failed arthroscopic SLAP tears at a minimum 2-year follow-up. The majority of patients obtained good to excellent outcomes using validated measures with a significant improvement in range of motion.