Short Stems and Stemless Shoulder Arthroplasty: Current Concepts Review.

Historically, the shoulder arthroplasty humeral component has been designed for the management of infections, tumours and fractures. In all these cases the stem was needed as a scaffold. Original humeral components were not developed for use in shoulder arthritis, so these designs and derivates had a long stem. The newest humeral implants innovations consist in shortening of the implant, or even removing the whole stem, to rely on stemless fixation at the level of the metaphysis. This implies the advantages of preserved bone stock, less stress shielding, eliminating the diaphyseal stress riser, easier implant removal at revision, and humeral component placement independent from the humeral diaphyseal axis. Nowadays, surgeons try to balance the need for a stable fixation of the humeral component with the potential need for revision surgery. Complications of revision shoulder arthroplasty are related to the need for removing a well-fixed humeral stem, the length of the procedure, and the need to treat severe bone loss.

Focal inlay resurfacing for full-thickness chondral defects of the femoral medial condyle may delay the progression to varus deformity.

INTRODUCTION: Full-thickness chondral defects at the knee joint predispose to the beginning of a degenerative process which final consequence is the compartment collapse and finally the deviation to varus, because the cartilage of the medial femoral condyle is the most frequently affected area. Likewise, people with these chondral defects are more likely to develop tricompartmental osteoarthritis, reason why early surgical management should be the treatment of choice. The aim of this study was to compare the pre- and post-operative lower limb alignment (mechanical axis), in cases of full-thickness chondral defects of the femoral medial condyle that have been managed by means of a prosthetic focal inlay resurfacing, at a minimum follow-up of five years. METHODS: A retrospective study of patients treated for chondral defects in the medial femoral condyle was performed. The inclusion criteria were patients who had undergone a focal inlay resurfacing and minimum follow-up of 5 years. Patients that required a concomitant valguizing tibial osteotomy were finally excluded. The follow-up analysis was performed by means of radiological examinations performed prior to surgery and at the last follow-up visit. The mean limb mechanical axis of the operated knees was calculated both pre- and post-operatively, and comparisons between these two settings were performed. RESULTS: Ten patients were included: eight men and two women. The mean age at the time of surgery was 55 (40-65) years. The mean follow-up was 9 years (range 5-15). The mean limb mechanical axis was 1.33 ± 4.16 in the pre-operative setting and 2.40 ± 5.50 in the post-operative setting (p = 0.441). CONCLUSION: In the setting of small to moderate size, unique femoral medial condyle full-thickness chondral lesions, filling the defect with an inlay prosthetic resurfacing may protect against the progression to varus deformity. LEVEL OF EVIDENCE: Therapeutic case series, Level IV.

Is there a significant decrease in the femoral cortical bone around Furlong® stems after 18 years of follow-up?

INTRODUCTION: In the context of total hip arthroplasty (THA), there are several reasons that have motivated the development of short stems. It has been postulated that short stems allow a better conservation of the bone stock if compared to conventional stems. As far as we have knowledge, the quantitative loss of diaphyseal bone stock in patients with standard femoral stems has not been fully described. The aim of this study was to provide evidences about the thickness of the cortical bone at the diaphysis in patients who have undergone unilateral THA with Furlong® stems with a minimum follow-up of 18 years. PATIENTS AND METHODS: A retrospective study of patients who underwent THA in a single hospital was performed. The inclusion criteria were patients who had undergone a non-cemented elective THA with a Furlong® stem, minimum follow-up of 18 years, and contralateral femur and hip without history of previous surgical procedures. The follow-up analysis was performed by means of radiological examinations performed at the last follow-up visit. Data related to the sex, age at surgery and adverse events registered during the follow-up were gathered. The cortical thickness index (CTI) and cortical thickness (CT) assessed at the last follow-up visit in anteroposterior pelvic X-rays were analyzed, both in the operated hip and in the non-operated hip (which was used as control). Calibration of the measurements was done by means of using the circumference of the head of the THA. RESULTS: The total number of patients who met the inclusion criteria was 22. There were 14 women and eight men. There were 12 left hips. The mean age at the time of surgery was 59.32 ± 6.83 (range 50-70) years. The mean follow-up was 20.86 ± 1.90 (range 18-24) years. The CTI was found to be 11.93% greater in the non-operated hips. The CT measured at 3 cm and 6 cm from lesser trochanter, and at 9 cm from the greater trochanter, was found to be 21.64%, 15.33% and 18.73% greater in the non-operated hips, respectively. CONCLUSION: After a minimum of 18 years from the implantation of a Furlong® stem, the bone density that surrounds the implant seems to involve a cortical bone ten percent less thick than the cortical bone of the non-operated contralateral side. With this stem, the cortical zones with less CT seem to be the lateral cortex at 9 cm from the greater trochanter, and the medial cortex at 3 and 6 cm from the lesser trochanter. LEVEL OF EVIDENCE: III, retrospective case-control study.