Interobserver reliability of radiographic assessment after radial head arthroplasty

Midterm follow-up of the Nexel total elbow arthroplasty

BACKGROUND

Aseptic loosening is one of the most common complications of total elbow arthroplasty (TEA). Modern implants, such as the Nexel, have been designed in an attempt to decrease loosening. The present study aims to report implant survivorship, radiographic assessment of loosening and lucency, and patient-reported outcome measures (PROMs) in patients treated with the Nexel TEA at midterm follow-up.

METHODS

Consecutive series of adult patients underwent TEA using the Nexel by a single surgeon via standardized technique. Patients with minimum 3-year follow-up with radiographic and PROM data were included. Survivorship was defined by the absence of revision. Loosening was assessed via the Wrightington method by 3 independent fellowship-trained shoulder and elbow surgeons. Lucency was analyzed across individual radiographic zones on orthogonal radiographs. PROMs included the Quick Disabilities of the Arm, Shoulder, and Hand questionnaire (QuickDASH), Patient-Rated Elbow Evaluation (PREE), and EuroQoL-5 Dimensions (EQ-5D).

RESULTS

Thirty-eight consecutive patients (22 female, 16 male) with a mean age of 67 years underwent TEA via a triceps-sparing isolated medial window approach. Mean follow-up was 5.5 years (range 3-9). Primary diagnoses were as follows: 19 osteoarthritis (OA), 9 rheumatoid arthritis (RA), 9 post-traumatic arthritis (PA), and 1 conversion of elbow arthrodesis. Overall survivorship was 97.4%, with 1 patient undergoing revision for infection. Loosening was found in 5.3% of elbows, averaged across 3 observers. Lucency was most pronounced at the level of the humeral condyles. PROMs demonstrated significant and clinically meaningful improvements in 76%, 92%, and 73% of patients for QuickDASH, PREE, and EQ-5D, respectively. No significant correlations were found between patient age, gender, loosening, lucency, and PROMs.

CONCLUSION

At midterm follow-up, the Nexel TEA demonstrated excellent overall survivorship and low rate of implant loosening. The single failure requiring revision for infection was conversion of a prior elbow arthrodesis. PROMs overall exhibited marked and consistent improvement from preoperative to final postoperative follow-up. Although promising, these results should be interpreted with some caution as long-term data regarding this prosthesis are still lacking.

Interobserver and Intraobserver Reliability of Classification Systems for Radiographic Complications After Radial Head Arthroplasty

PURPOSE

Although several classifications are used to assess radiographs following radial head arthroplasty (RHA), including the Popovic classification for radiolucency, the Chanlalit classification for stress shielding (SS), the Brooker classification for heterotopic ossification (HO), and the Broberg-Morrey classification for radiocapitellar arthritis, little is known about the reliability of these classification systems. The purpose of this study was to determine the interobserver and intraobserver reliability of these classifications.

METHODS

Six orthopedic surgeons at various levels of training reviewed elbow radiographs of 20 patients who underwent RHA and classified them according to the Popovic, Chanlalit, Brooker, and Broberg-Morrey classifications for radiolucency, SS, HO, and RHA, respectively. Four weeks after initial review, radiographic reviews were repeated. Reliability was measured using the Fleiss kappa and the intraclass correlation coefficient. Agreement was interpreted as none (<0), slight (0.01-0.2), fair (0.21-0.4), moderate (0.41-0.6), substantial (0.61-0.8), and almost perfect (0.81-1) based on agreement among attending surgeons.

RESULTS

Among fellowship-trained attending surgeons, interobserver reliability was slight for SS (Chanlalit) and the categorical interpretation of radiolucency (Popovic), fair for radiocapitellar arthritis (Broberg-Morrey) and HO (Brooker), and substantial for the ordinal interpretation of radiolucency (Popovic). Residents had a higher interobserver reliability than attending physicians when using the Brooker classification. Mean intraobserver reliability was fair for SS (Chanlalit) and the categorical interpretation of radiolucency (Popovic), moderate for HO (Brooker) and radiocapitellar arthritis (Broberg-Morrey), and almost perfect for the ordinal interpretation of radiolucency (Popovic). Trainees had higher intraobserver reliability than attending surgeons using the SS (Chanlalit) classification.

CONCLUSIONS

The number of Popovic zones is reliable for communication between physicians, but caution should be taken with the Brooker, Chanlalit, Broberg-Morrey, and categorical interpretation of the Popovic classifications. All the classifications had better intraobserver than interobserver reliability.

CLINICAL RELEVANCE

Reliability of classification systems for radiographic complications after RHA is less than substantial except the number of zones of radiolucency; therefore, caution is required when drawing conclusions based on these classifications.

Radial head fractures

The shape and size of the radial head is highly variable but correlates to the contralateral side. The radial head is a secondary stabilizer to valgus stress and provides lateral stability. The modified Mason-Hotchkiss classification is the most commonly used and describes three types, depending on the number of fragments and their displacement. Type 1 fractures are typically treated conservatively. Surgical reduction and fixation are recommended for type 2 fractures, if there is a mechanical block to motion. This can be done arthroscopically or open. Controversy exists for two-part fractures with >2 mm and <5 mm displacement, without a mechanical bloc as good results have been published with conservative treatment. Type 3 fractures are often treated with radial head replacement. Although radial head resection is also an option as long-term results have been shown to be favourable. Radial head arthroplasty is recommended in type 3 fractures with ligamentous injury or proximal ulna fractures. Failure of primary radial head replacement may be due to several factors. Identification of the cause of failure is essential. Failed radial head arthroplasty can be treated by implant removal alone, interposition arthroplasty, revision radial head replacement either as a single stage or two-stage procedure.