Does Matching Femoral Size and Shape Improve Bone Fit and Patient-reported Outcomes in TKA? A Matched Controlled Study.

BACKGROUND: Some researchers have suggested that achieving good component coverage over the host bone during TKA (while avoiding implant overhang) may help achieve durable implant fixation and may be associated with better outcomes scores. However, the evidence about this is limited and contradictory. Contemporary morphometric TKA includes a wide array of components with various shapes and sizes, based on large anatomic databases and specific software that simulates bone cuts. Morphometric tibial components have shown improved bone coverage and better clinical outcomes than standardized implants, but the role of morphometric femoral components in bone coverage has not been studied precisely. QUESTIONS/PURPOSES: In a retrospective, controlled study that used patient matching, we asked: (1) Does the use of a contemporary morphometric component with more available sizes provide better femoral component fit and bone coverage than an earlier design with fewer sizes? (2) Are component fit and the presence of component overhang or underhang associated with different Knee Society Score (KSS) or Knee Injury and Osteoarthritis Outcome Score (KOOS) for Joint Replacement? METHODS: From 2012 to 2013, we performed 403 TKAs according to the following criteria: TKA performed for primary tricompartmental arthritis of the knee; varus, valgus, and flexion deformity less than 15°; and age between 18 and 85 years on the day of surgery. Among these 403 TKAs, 237 were performed using a morphometric implant and 166 with the earlier nonmorphometric implant. At 2 years of follow-up, 3% of patients in the morphometric group and 5% in the nonmorphometric group were lost to follow-up. Based on age, BMI, gender, and preoperative KSS and KOOS, two groups of 30 patients were matched in a 1:1 ratio from this longitudinally maintained database. Clinical outcomes were measured preoperatively and at a minimum follow-up of 2 years in both groups, using the KSS and KOOS. We evaluated postoperative CT images for each patient to analyze femoral implant rotation, bone coverage, and overhang and underhang status. RESULTS: The overhang status was similar between the two groups (23% had an overhang component in the morphometric knee group and 27% had an overhang component in the nonmorphometric knee group), and overhang was most frequently found in the lateral distal zone and medial anterior chamfer. Better cortical bone coverage was found in the morphometric knee group, with a thinner bone margin between the component edge and cortical border (morphometric group: 3 mm versus nonmorphometric knee group: 5 mm; p = 0.01). In general, there were few between-group differences in terms of patient-reported outcomes; of the seven metrics we analyzed, only the KSS favored the morphometric knee implant by a margin larger than the minimum clinically important difference (KSS mean difference: 21 points for the morphometric knee group; p < 0.05). Overhang of the femoral component of > 2 mm was associated with poorer KOOS, but not KSS, whereas a thinner bone margin had a beneficial impact on pain and global clinical scores (KOOS and KSS: p < 0.05). CONCLUSION: The use of a morphometric femoral component design showed slightly improved bone fit and pain score according to the KSS at midterm follow-up compared with earlier implants with fewer sizes. Overhang > 2 mm was associated with worse KOOS. The tendency toward better outcomes in morphometric implants warrants longer-term evaluation before any definite conclusions about the association between bone fit and clinical results can be drawn.Level of Evidence Level III, therapeutic study.

Three- and four-part displaced proximal humeral fractures in patients older than 70 years: reverse shoulder arthroplasty or nonsurgical treatment?

BACKGROUND: The objective of our study was to evaluate the results of surgical treatment by reverse shoulder arthroplasty (RSA) compared with nonsurgical treatment after 2 years of follow-up in patients aged 70 years or older with displaced 3-part or 4-part proximal humeral fractures. METHODS: Two groups were formed: the RSA group (n = 28) and the nonsurgical group (n = 32). Minimum follow-up was 2 years. We included patients with 3-part or 4-part fractures according to the Neer classification. Main outcome measures were the Constant-Murley score, the 11-item version of the Disabilities of the Arm, Shoulder and Hand score, and the Subjective Shoulder Value score. An autonomy score, a cognitive assessment score, and a pain score were also measured. RESULTS: Clinical features in the 2 groups were not significantly different. The Constant-Murley mean score was significantly higher for the RSA group (82.1% vs. 76.8%; P = .03). Amplitudes were all higher in favor of the RSA group (P < .02). There was no significant difference in mean score on the 11-item version of the Disabilities of the Arm, Shoulder and Hand score, the preoperative and postoperative Subjective Shoulder Value score, the autonomy score, the cognitive assessment score, or the pain score in both groups at the last follow-up. The complication rate was higher for the RSA group. CONCLUSIONS: These results suggest that RSA treatment of proximal humeral fractures with 3-part or 4-part displaced fragments in elderly patients provides better functional outcomes than does nonsurgical treatment. However, the observed clinical difference was relatively small. This solution must be proposed only to patients who have a significant functional demand.

Morphometric Tibial Implant Decreases Posterior Overhang Rate and Improves Clinical Outcomes: Results of a Prospective, Matched Controlled Study.

BACKGROUND: Tibial implant's positioning in total knee arthroplasty (TKA) requires a compromise between implant's rotation and bone coverage. We hypothesized that morphometric tibial trays (MTTs) would improve implant positioning and clinical outcomes as compared with symmetrical tibial trays. METHODS: Thirty-three patients were included prospectively according to the following criteria: age from 18 to 85 years, body mass index <35 kg/m2, and posterostabilized cemented TKA performed for primary arthritis. Patients were matched for age, gender, body mass index, and preoperative international knee society (IKS) scoring system and Knee Injury and Osteoarthritis Outcome Score (KOOS) pain score, in a 1:1 fashion with patients from a prospectively collected database receiving a symmetrical tibial tray TKA. Tibial implant's rotation, bone coverage, and the percentage of patients with a posterior overhang (PO) >3 mm were assessed using computerized tomography. The IKS and the KOOS were compared at 3-year follow-up. RESULTS: Bone coverage (90% vs 88%, P = .07) and rotation (mean difference 0.7 ± 3°; P = .69) were not different between the 2 groups. The percentage of patient with a PO was lower in the morphologic group (2/33 vs 14/33, P = .01, odds ratio = 10.3 [2.12-50.24]). Functional scores were superior in the morphometric group: IKS (mean difference 20 ± 21 points; P = .0005), mainly due to a difference in the IKS pain subscore (mean difference 11 ± 15 points; P = .0002). According to the multivariate analysis, an MTT had a positive, independent effect on IKS pain (P = .006) and KOOS pain subscores (P = .03) at the last follow-up. CONCLUSION: The use of an MTT in TKA did not modify the tibial implant position in the axial plane; however, it decreased implant's posterior overhang and improved functional scores. The clinical improvement was mainly found on pain scores.

Fixed-hinge cemented modular implants: An effective reconstruction technique following primary distal femoral bone tumor resection. A 136-case multicenter series.

BACKGROUND: Reconstruction by endoprosthesis is widespread after bone tumor resection. The design and type of fixation and of hinge remain a matter of debate. The aim of the present study was to assess survival, complications and functional results in a homogeneous series of adult patients undergoing bone defect reconstruction following distal femoral tumor resection, using a single model of fixed-hinge cemented endoprosthesis, at a minimum 5 years' follow-up. HYPOTHESIS: The study hypotheses were that loosening and infection are the main causes of failure, and that this type of reconstruction is reliable following distal femoral resection. PATIENTS AND METHODS: All patients aged over 17 years undergoing reconstruction using the Stanmore Mets® fixed-hinge cemented modular endoprosthesis following distal femoral resection for primary bone tumor in 4 French reference centers between 2004 and 2013 were included. Epidemiological data, MSTS functional score, clinical and radiological examination results, complications and survival with types of failure according to the Henderson classification were assessed. RESULTS: One hundred and thirty-six patients (68 male, 68 female; mean age, 41.2 years [range, 17-77 years]) were included. Mean follow-up was 81 months [range, 61-134 months]. Thirty-two patients (38%) experienced a total 67 complications requiring surgical revision: mainly infection (n=28) or mechanical failure (n=26). Overall implant survival was 78% at 5 years. There were 30 implant failures on the Henderson classification. Mean MSTS score was 82%. DISCUSSION: The present results are comparable to those of the literature and for other types of reconstruction. Recent meta-analyses suggest that type of hinge and of stem fixation have little effect on implant survival. International comparative studies are needed to determine the exact role of each type of reconstruction according to the patient profile. LEVEL OF EVIDENCE: IV, multicenter retrospective series.