High tibial osteotomy with modern PEEK implants is safe and leads to lower hardware removal rates when compared to conventional metal fixation: a multi-center comparison study.

PURPOSE: Various implant materials have been used in medial, opening-wedge high tibial osteotomy (HTO) including traditional metal and modern polyetheretherketone (PEEK) implants. The purpose of this study was to compare metal and PEEK implants and determine safety, varus deformity correction, as well as short- to mid-term hardware removal and arthroplasty rates. METHODS: HTO performed with metal and PEEK implants were reviewed between 2000 and 2015 at two institutions with a minimum of 2 years follow-up. Postoperative complications, radiographic measures, and osteotomy union were compared between groups using Kruskal-Wallis and Fisher's exact testing. Survival free of hardware removal and arthroplasty was compared between groups using Kaplan-Meier testing. Risk factors for HTO conversion to arthroplasty were examined using Cox proportional hazards regression. RESULTS: Ninety-five HTOs were performed in 90 patients (59 M, 31 F) using 50 metal and 45 PEEK implants. Mean follow-up was 4.2 years (range 2.0-16.5). Two metal and two PEEK HTO patients experienced nonunions, resulting in revision HTO at a mean of 1.0 years postoperatively (range 0.4-1.4 years). Both implant groups demonstrated similar, significant improvements in coronal deformity, with mean angulation improving from 6.0° and 5.4° varus preoperatively to 1.1° and 1.0° valgus postoperatively for the metal (p < 0.01) and PEEK groups (p < 0.01), respectively. 2- and 5-year hardware removal-free survival was 94% and 94% for PEEK, which was significantly superior to 80% and 73% observed for metal (p = 0.02). 2- and 5-year arthroplasty-free survival was similar for the metal (98% and 94%) and PEEK groups (100% and 78%) (n.s.). HTO performed for focal cartilage defects was observed to demonstrate decreased arthroplasty risk (HR 0.36, p = 0.03) when compared to HTO performed for osteoarthritis. CONCLUSIONS: Both metal and PEEK implants were found to be effective in obtaining and maintaining coronal varus deformity correction, with 88% overall arthroplasty-free survival at 5 years. Metal fixation demonstrated a higher rate of hardware removal while HTO performed for medial compartment osteoarthritis predicted conversation to arthroplasty. LEVEL OF EVIDENCE: III.

Trends in the Surgical Management of Acromioclavicular Joint Arthritis Among Board-Eligible US Orthopaedic Surgeons.

PURPOSE: (1) Define the epidemiologic trend of distal clavicle excision (DCE) for acromioclavicular (AC) joint arthritis among board-eligible orthopaedic surgeons in the United States, (2) describe the rates and types of reported complications of open and arthroscopic DCE, and (3) evaluate the effect of fellowship training on preferred technique and reported complication rates. METHODS: The American Board of Orthopaedic Surgery (ABOS) database was used to identify DCE cases submitted by ABOS Part II Board Certification examination candidates. Inclusion criteria were predetermined using a combination of ICD-9 and CPT codes. Cases were dichotomized into 2 groups: open or arthroscopic DCE. The 2 groups were then analyzed to determine trends in annual incidence, complication rates, and surgeon fellowship training. RESULTS: From April 2004 to September 2013, there were 3,229 open and 12,782 arthroscopic DCE procedures performed and submitted by ABOS Part II Board Eligible candidates. Overall, the annual incidence of open DCE decreased (78-37 cases per 10,000 submitted cases, P = .023). Although the annual number of arthroscopic DCE remained steady (1160-1125, P = .622), the percentage of DCE cases performed arthroscopically increased (65%-79%, P = .033). Surgeons without fellowship training were most likely to perform a DCE via an open approach (31%) whereas surgeons with sports medicine training were more likely to perform DCE arthroscopically compared with other fellowship groups (88%, P < .001). Open DCE was associated with a higher surgical complication rate overall when compared with arthroscopic DCE (9.4% vs 7.6%, respectively; P < .001). When compared with other fellowship-trained surgeons, sports medicine surgeons maintained a lower reported surgical complication rate whether performing open or arthroscopic DCE (5.5%, P = .027). CONCLUSIONS: In recent years, open management of AC joint arthritis has declined among newly trained, board-eligible orthopaedic surgeons, possibly because of an increased complication rate associated with open treatment. Fellowship training was significantly associated with the type of treatment (open vs arthroscopic) rendered and complication rates. LEVEL OF EVIDENCE: Level IV, case series.

Increased Femoral Head Offset is Associated With Elevated Metal Ions in Asymptomatic Patients With Metal-on-Polyethylene Total Hip Arthroplasty.

BACKGROUND: Predisposing factors for trunnionosis and elevated metal ion levels in metal-on-polyethylene (MOP) total hip arthroplasty (THA) are currently unknown. METHODS: This retrospective cohort study enrolled 80 consecutive patients (43 males) with an asymptomatic MOP THA at 2- to 5-year follow-up and no other metal implants. Serum cobalt (Co) and chromium (Cr) levels were collected at the time of enrollment, and retrospective review was performed regarding demographic, implant, and surgical characteristics. Mean age at the time of surgery was 65.7 years (range 35.6-85.9 years), and mean postoperative follow-up was 28.7 months (range 24.4-58.9 months). RESULTS: Femoral head offset was the only evaluated factor shown to increase serum Co ion levels above baseline within the cohort. Mean difference in Co level for high and low offset implants was 0.58 ppb (95% confidence interval [CI] = 0.05-1.11 ppb; P = .03). Mean difference in Cr level for high and low offset implants was 0.19 ppb (95% CI = -0.23 to 0.60 ppb; P = .37). Mean difference in Co level for small and large femoral heads was 0.20 ppb (95% CI = -0.41 to 0.81 ppb; P = .59). Mean difference in Cr level for small and large femoral heads was 0.28 ppb (95% CI = -0.18 to 0.74 ppb; P = .06). Age, gender, Harris Hip Score, and implant duration were not associated with changes in metal ion levels. CONCLUSION: Femoral head offset appears to be an important source of elevated metal ion levels in MOP THA. Further studies will be needed to understand if increasing femoral head offset is associated with subsequent adverse local tissue reactions.

High Tibial Osteotomy with a Modern Polyetheretherketone (PEEK) System: Mid-Term Results at a Mean of 6 Years Follow-Up.

The purpose of this study was to determine patient-reported outcomes, hardware removal rates, as well as conversion to arthroplasty at mid-term follow-up following high tibial osteotomy (HTO) with a modern polyetheretherketone (PEEK) system. All PEEK system-based HTOs performed at a single institution between January 2010 and January 2016 with a minimum of 2 years follow-up were reviewed. Rates of postoperative complications, hardware removal and conversion to arthroplasty were calculated. Patient-reported outcomes including visual analog pain scale (VAS), Tegner activity scale, Lysholm, Knee Injury and Osteoarthritis Outcome Score (KOOS), and 36-Item Short Form Survey (SF-36) were obtained. Forty-seven HTOs in 43 patients (mean age: 37.6 ± 10.8 years; 30 M, 13 F) were followed for a mean of 6.0 ± 1.5 years. A total of four postoperative complications occurred in three patients, resulting in an overall complication rate of 6.4%. Hardware removal occurred in three patients at a mean of 0.73 ± 0.53 years after surgery, with overall survival free of hardware removal of 96% (95% confidence interval [CI]: 85-99) at 1 year, 94% (95% CI: 82-98) at 2 years, and 94% (95% CI: 82-98) at 8 years. Conversion to arthroplasty occurred in three patients at a mean of 3.2 ± 1.0 years after surgery, with mean survival of 100% (95% CI: 94-100) at 1 year, 100% (95% CI: 94-100) at 2 years, and 93% (95% CI: 81-98) at 8 years. VAS at rest improved, from 3.1 ± 2.5 preoperatively to 1.1 ± 1.6 postoperatively (p < 0.001). Patients remained active, with a mean Tegner activity scale of 4.4 ± 1.4 at final follow-up and satisfactory Lysholm, KOOS, and SF-36 scores. At mid-term follow-up, medial opening-wedge HTO using a modern PEEK-based system was found to be safe, efficacious, and durable, with satisfactory outcome scores and a low rate of conversion to arthroplasty. PEEK-based implants were found to have low hardware removal rates of 6% at 5 years, which compares favorably to historic metal fixation. This is a Level III study.