Pyrocarbon interposition shoulder arthroplasty in advanced collapse of the humeral head.

BACKGROUND: Pyrocarbon (PyC) interposition shoulder arthroplasty can be used to treat advanced collapse of the humeral head after avascular necrosis. OBJECTIVES: We examined outcomes for this bone-preserving implant which has a PyC coating and a novel biomechanical concept. MATERIALS AND METHODS: For a minimum of 2 years, we followed 10 patients (4 men, 6 women, 55.6 ± 12.9 years) treated with a free interposition PyC arthroplasty ("snookerball") due to advanced humeral head collapse but with an intact glenoid and rotator cuff. Anteroposterior radiographs, the Constant score (CS), adjusted CS, DASH score, and the EuroQol 5D-5L score from the preoperative and the latest follow-up presentation were compared. RESULTS: At a mean of 3.6 years (±15 months), the mean absolute CS was 70.6 (±13.6; adjusted CS 81.4 ± 16.4), the DASH score was 25.6 (±16.1), the mean EQ subjective VAS score was 72.6 (±15.9), and the EQ index score was 0.9 (±0.11). Scores improved: CS: +63.2 ± 12.9; adjusted CS: +72.9 ± 15.5; DASH: +47.2 ± 14.7; EQ VAS: +42.6 ± 16.8; EQ index score +0.52 ± 0.23. Mean glenoid erosion was 1.4 mm (±1.3 mm), thinning of the tuberosities was -0.8 mm (±3.3 mm), and superior migration of the implant was 2.0 mm (±2.2). A thin radiolucent zone around the implant with bone densification on the metaphyseal side was observed in all cases (mean 1.8 ±â€¯0.6 mm). CONCLUSIONS: Excellent improvement of function and quality of life which are comparable to total shoulder arthroplasty data were observed. Significant bone remodeling occurs in the metaphysis around the implant. Further studies are needed to evaluate longevity and applicability of the implant. These results indicate that advanced collapse of the humeral head with an intact glenoid and rotator cuff are an optimal indication for this implant.

Progressive glenoid bone loss caused by erosion in humeral head resurfacing.

BACKGROUND: Cementless surface replacement of the shoulder represents an alternative to conventional stemmed anatomic prostheses. Glenoid erosion is a well-known complication in hemiarthroplasty. However, there is limited data concerning radiographic evaluation and prognostic factors for this phenomenon. OBJECTIVES: The aim of our study was to determine the development of glenoid erosion following shoulder resurfacing using a new measurement technique and detect potential prognostic factors. MATERIALS AND METHODS: We performed a retrospective analysis on 38 shoulders undergoing humeral head resurfacing with a mean follow-up of 65.4 ± 43 months. Clinical and radiographic evaluation followed a standardized protocol including pre- and postoperative Constant score, active range of motion, and X­rays in true anteroposterior view. Three independent observers performed measurements of glenoid erosion. RESULTS: We found good interobserver reliability for glenoid erosion measurements (intraclass correlation coefficient [ICC] 0.74-0.78). Progressive glenoid erosion was present in all cases, averaging 5.5 ± 3.9 mm at more than 5 years' follow-up. Male patients demonstrated increased glenoid bone loss within the first 5 years (p < 0.04). The mean Constant score improved to 55.4 ± 23.6 points at the latest follow-up. Younger age was correlated to increased functional outcome. Revision rate due to painful glenoid erosion was 37%. CONCLUSIONS: Glenoid erosion can be routinely expected in patients undergoing humeral head resurfacing. Painful glenoid erosion leads to deterioration in functional outcome and necessitates revision surgery in a high percentage of cases.

[Endoprosthesis infections of the shoulder: diagnosis and therapy algorithm]. / Endoprotheseninfektionen der Schulter : Diagnose und Therapiealgorithmus.

Periprosthetic shoulder joint infections are encountered by orthopedic surgeons mainly as complex situations which are highlighted by difficult treatment modalities. In a confirmed infection the general therapeutic principle is a surgical procedure. Several strategies orientate on the cause of an infection, the time course of postoperative symptoms, the pathogenicity of the isolated species and the specific comorbidities of the patient. An arthroscopic joint lavage with open debridement and component change may suffice in selected acute cases whereas a two-stage revision augmented by an articulating antibiotic spacer is mandatory in chronic infections. Early recognition is of paramount importance in order to prevent further spread, sepsis or even fatal outcome. Low grade infections are challenging conditions in terms of diagnosis and treatment. This article summarizes the principles of current classification, detection and treatment strategies for periprosthetic shoulder joint infections.

Is noncontact ACL injury associated with the posterior tibial and meniscal slope?

BACKGROUND: The risk of noncontact ACL injury reportedly is increased in patients with a greater posterior tibial slope (PTS), but clinical data are inconsistent. It is unclear whether the medial and lateral PTSs have a different impact on this connection. It also is unknown whether the meniscal slope (MS) is associated with ACL injury. PATIENTS/METHODS: Using MRI, we compared the medial and lateral PTSs and MSs separately in 55 matched pairs of patients with isolated noncontact ACL injuries and a control group. RESULTS: Neither the PTS nor the relative difference between the medial and lateral PTSs differed between groups. In contrast, the lateral MS was greater with ACL injuries: 2.0° versus -2.7° in males with and without ACL injury and 1.7° versus -0.9 in females. Uninjured females had a greater PTS than males: 4.9° versus 3.0° in females and males medially, respectively; 5.7° versus 4.0° lateral. CONCLUSIONS: There is no obvious link between the medial or lateral PTSs and ACL injury, and there is no obvious link between the relative difference in the medial and lateral PTSs and noncontact ACL injury. However, a greater lateral MS may indicate a greater risk of injury. The PTS can differ between the genders but the average difference is small. LEVEL OF EVIDENCE: Level II, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.