Background: Short femoral stems designed to spare bone stock and improve load transfer at the proximal femur have been introduced in the last years. However, little is known on the long-term results of these stems. Hypothesis: short cementless stems have low rate of revision at mid term follow up with limited bone remodelling in relation to the physiological loading in the proximal femur. Materials and Methods: We prospectively followed 64 patients (72 hips) undergoing total hip arthroplasty with a femoral stem designed to achieve a pure metaphyseal fixation. Patients with hip fracture, femoral neck deformity and osteoporotic bone were excluded. Clinical evaluations were performed annually until the last follow-up, a minimum of nine years after surgery. At each follow-up, implant positioning was assessed on conventional plain films with a computed radiographic evaluation. Results: Harris hip score, Womac and SF-36 were significantly improved compared to preoperative status. Computed radiographic analysis showed a neutral alignment of the stem in 56% of cases, a varus-valgus alignment < 5° in 36% and ≥ 5° in 8%. Stem subsidence was observed in 12 hips but was less than 4mm in all cases. Calcar height remained unchanged over time. Adaptive bone remodelling, including proximal bone resorption and distal cortical hypertrophy were not observed at follow-up. No patients had aseptic loosening of the stem nor were radiolucent lines detectable at the level of the porous coating. Survivorship analysis showed a 100% survival rate of the stem at nine years. Discussion: The results of this study showed that a femoral stem designed to achieve a pure metaphyseal fixation may obtain satisfactory clinical outcomes in high rates of patients without compromise implant stability. The limited periprosthetic bone remodelling observed after a minimum of 9 years follow-up suggest that this type of implant my improve mechanical stresses on host bone compared with standard stems with diaphyseal fixation. Level of evidence: IV. Key words: total hip arthroplasty; femoral stem; proximal fixation; bone remodeling; thigh pain
THIGH PAIN, SUBSIDENCE AND SURVIVAL USING A SHORT CEMENTLESS FEMORAL STEM WITH PURE METAPHYSEAL FIXATION AT MINIMUIM 9-YEAR FOLLOW-UP / Cinotti, Gianluca; Della Rocca, A; Sessa, Pasquale; Ripani, Fr; Giannicola, G.. - In: ORTHOPAEDICS & TRAUMATOLOGY: SURGERY & RESEARCH. - ISSN 1877-0568. - STAMPA. - 99:1(2013), pp. 30-36. [10.1016/j.otsr.2012.09.016]
THIGH PAIN, SUBSIDENCE AND SURVIVAL USING A SHORT CEMENTLESS FEMORAL STEM WITH PURE METAPHYSEAL FIXATION AT MINIMUIM 9-YEAR FOLLOW-UP
CINOTTI, Gianluca;SESSA, PASQUALE;Giannicola G.
2013
Abstract
Background: Short femoral stems designed to spare bone stock and improve load transfer at the proximal femur have been introduced in the last years. However, little is known on the long-term results of these stems. Hypothesis: short cementless stems have low rate of revision at mid term follow up with limited bone remodelling in relation to the physiological loading in the proximal femur. Materials and Methods: We prospectively followed 64 patients (72 hips) undergoing total hip arthroplasty with a femoral stem designed to achieve a pure metaphyseal fixation. Patients with hip fracture, femoral neck deformity and osteoporotic bone were excluded. Clinical evaluations were performed annually until the last follow-up, a minimum of nine years after surgery. At each follow-up, implant positioning was assessed on conventional plain films with a computed radiographic evaluation. Results: Harris hip score, Womac and SF-36 were significantly improved compared to preoperative status. Computed radiographic analysis showed a neutral alignment of the stem in 56% of cases, a varus-valgus alignment < 5° in 36% and ≥ 5° in 8%. Stem subsidence was observed in 12 hips but was less than 4mm in all cases. Calcar height remained unchanged over time. Adaptive bone remodelling, including proximal bone resorption and distal cortical hypertrophy were not observed at follow-up. No patients had aseptic loosening of the stem nor were radiolucent lines detectable at the level of the porous coating. Survivorship analysis showed a 100% survival rate of the stem at nine years. Discussion: The results of this study showed that a femoral stem designed to achieve a pure metaphyseal fixation may obtain satisfactory clinical outcomes in high rates of patients without compromise implant stability. The limited periprosthetic bone remodelling observed after a minimum of 9 years follow-up suggest that this type of implant my improve mechanical stresses on host bone compared with standard stems with diaphyseal fixation. Level of evidence: IV. Key words: total hip arthroplasty; femoral stem; proximal fixation; bone remodeling; thigh painI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
