Various short hip stems have been introduced with differing implant concepts of femoral fixation and implant length. There is a lack of proper classification for short hip stems, with a clear and accepted definition for implant length and extent of bone preservation in the metaphyseal and diaphyseal femur. This study analyzed the length of short hip stems. Stems were divided into collum, partial collum, and trochanter-sparing implants. An additional category was added, trochanter harming, which was defined as interruption of the circumferential integrity of the femoral neck. For all of the femoral components described, the designs were compared, excluding stems with insufficient clinical data. The 15 finally selected stems were classified as collum (1 stem), partial collum (7 stems), trochanter sparing (4 stems), and trochanter harming (3 stems). Mid-term results (>5 years of follow-up) were available for only 3 designs in the partial collum group. Taking into account the results of short-term studies (<5 years of follow-up), the femoral revision rate per 100 observed component years was <1 for most total hip arthroplasties. However, the studies varied greatly regarding level of significance, and short hip stems without published results are available commercially. Short hip stems cannot be circumscribed by a simple length limit. For some designs, clinical data collected from large patient cohorts showed a survivorship comparable to traditional stems. In cases that must be revised, this often can be performed with a conventional primary stem, fulfilling the promise to preserve bone for potential future revisions in younger patients.

Total hip replacement is showing, during the last decades, a progressive evolution toward principles of reduced bone and soft tissue aggression. These principles have become the basis of a new philosophy, tissue sparing surgery. Regarding hip implants, new conservative components have been proposed and developed as an alternative to conventional stems. Technical and biomechanical characteristics of metaphyseal bone-stock-preserving stems are analyzed on the basis of the available literature and our personal experience. Mayo, Nanos and Metha stems represent, under certain aspects, a design evolution starting from shared concepts: reduced femoral violation, non-anatomic geometry, proximal calcar loading and lateral alignment. However, consistent differences are level of neck preservation, cross-sectional geometry and surface finishing. The Mayo component is the most time-tested component and, in our hands, it showed an excellent survivorship at the mid-term follow-up, with an extremely reduced incidence of aseptic loosening (partially reduced by the association with last generation acetabular couplings). For 160 implants followed for a mean of 4.7 years, survivorship was 97.5% with 4 failed implants: one fracture with unstable stem, 1 septic loosening and 2 aseptic mobilizations. DEXA analysis, performed on 15 cases, showed a good calcar loading and stimulation, but there was significant lateral load transfer to R3–R4 zones, giving to the distal part of the stem a function not simply limited to alignment. Metaphyseal conservative stems demonstrated a wide applicability with an essential surgical technique. Moreover, they offer the options of a “conservative revision” with a conventional primary component in case of failure and a “conservative revision” for failed resurfacing implants.

The choice between different surgical options depends on bone defect dimension and characteristics but are also patient-related. Reestablishment of well-aligned and stable implants is necessary for successful reconstruction, but this can't be accomplished without a sufficient restoration of an eventual bone loss.

Introduction Biophysical stimulation is a non-invasive therapy used in orthopaedic practice to increase and enhance reparative and anabolic activities of tissue. Methods A sistematic web-based search for papers was conducted using the following titles: (1) pulsed electromagnetic field (PEMF), capacitively coupled electrical field (CCEF), low intensity pulsed ultrasound system (LIPUS) and biophysical stimulation; (2) bone cells, bone tissue, fracture, non-union, prosthesis and vertebral fracture; and (3) chondrocyte, synoviocytes, joint chondroprotection, arthroscopy and knee arthroplasty. Results Pre-clinical studies have shown that the site of interaction of biophysical stimuli is the cell membrane. Its effect on bone tissue is to increase proliferation, synthesis and release of growth factors. On articular cells, it creates a strong A 2A and A 3 adenosine-agonist effect inducing an anti-inflammatory and chondroprotective result. In treated animals, it has been shown that the mineralisation rate of newly formed bone is almost doubled, the progression of the osteoarthritic cartilage degeneration is inhibited and quality of cartilage is preserved. Biophysical stimulation has been used in the clinical setting to promote the healing of fractures and non-unions. It has been successfully used on joint pathologies for its beneficial effect on improving function in early OA and after knee surgery to limit the inflammation of periarticular tissues. Discussion The pooled result of the studies in this review revealed the efficacy of biophysical stimulation for bone healing and joint chondroprotection based on proven methodological quality. Conclusion The orthopaedic community has played a central role in the development and understanding of the importance of the physical stimuli. Biophysical stimulation requires care and precision in use if it is to ensure the success expected of it by physicians and patients.

Pre-clinical studies have shown that treatment by pulsed electromagnetic fields (PEMFs) can limit the catabolic effects of pro-inflammatory cytokines on articular cartilage and favour the anabolic activity of the chondrocytes. Anterior cruciate ligament (ACL) reconstruction is usually performed by arthroscopic procedure that, even if minimally invasive, may elicit an inflammatory joint reaction detrimental to articular cartilage. In this study the effect of I-ONE PEMFs treatment in patients undergoing ACL reconstruction was investigated. The study end-points were (1) evaluation of patients' functional recovery by International Knee Documentation Committee (IKDC) Form; (2) use of non-steroidal antiinflammatory drugs (NSAIDs), necessary to control joint pain and inflammation. The study design was prospective, randomized and double blind. Sixty-nine patients were included in the study at baseline. Follow-up visits were scheduled at 30, 60 and 180 days, followed by 2-year follow-up interview. Patients were evaluated by IKDC Form and were asked to report on the use of NSAIDs. Patients were randomized to active or placebo treatments; active device generated a magnetic field of 1.5 mT at 75 Hz. Patients were instructed to use the stimulator (I-ONE) for 4 h per day for 60 days. All patients underwent ACL reconstruction with use of quadruple hamstrings semitendinosus and gracilis technique. At baseline there were no differences in the IKDC scores between the two groups. At follow-up visits the SF-36 Health Survey score showed a statistically significant faster recovery in the group of patients treated with I-ONE stimulator (P \ 0.05). NSAIDs use was less frequent among active patients than controls (P \ 0.05). Joint swelling resolution and return to normal range of motion occurred faster in the active treated group (P \ 0.05) too. The 2-year follow-up did not shown statistically significant difference between the two groups. Furthermore for longitudinal analysis the generalized linear mixed effects model was applied to calculate the group 9 time interaction coefficient; this interaction showed a significant difference (P \ 0.0001) between the active and placebo groups for all investigated variables: SF-36 Health Survey, IKDC Subjective Knee Evaluation and VAS. Twenty-nine patients (15 in the active group; 14 in the placebo group) underwent both ACL reconstruction and meniscectomy; when they were analysed separately the differences in SF-36 Health Survey scores between the two groups were 123Knee Surg Sports Traumatol Arthrosc (2008) 16:595-601 DOI 10.1007 larger then what observed in the whole study group (P \ 0.05). The results of this study show that patient's functional recovery occurs earlier in the active group. No side effects were observed and the treatment was well tolerated. The use of I-ONE should always be considered after ACL reconstruction, particularly in professional athletes, to shorten the recovery time, to limit joint inflammatory reaction and its catabolic effects on articular cartilage and ...

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Periprosthetic bone loss is a major cause for concern in patients undergoing total hip arthroplasty (THA). There are many different factors that may determine the pattern of bone loss and bone remodelling following THA, such as the quality of the bone before the hip replacement, skeletal bone mass at the time of the operation, material and method of fixation and implant design. Recent developments in dual-energy X-ray absorptiometry (DXA) have made it possible to quantify bone mineral density (BMD) to evaluate changes around the prosthesis and to measure bone stock and bone density redistribution after a total hip replacement. In this cross-sectional multicentre clinical study the DXA method was used to compare bone mass after uncemented THA of a custom-made stemless design with five groups of conventional cementless implants (Alloclassic, Mayo, CFP, IPS, ABG). The adaptive bone changes of the proximal femur three years after implantation were evaluated. Periprosthetic BMD was measured in 130 subjects in the seven regions of interest (ROI) based on Gruen zones. Significant differences were found between the stemless implant and the other five groups in zones 1, 4 and 7. The CFP, IPS, and ABG groups showed decreased BMD in ROI 1, and the Mayo, IPS and Alloclassic in ROI 7. An increased BMD in ROI 4 was observed in the Mayo, IPS, ABG and Alloclassic groups. The results of the present study suggest that a conservative stemless implant with complete proximal load transfer produces a homogeneous and more physiological redistribution of bone density, allowing maintenance of proximal periprosthetic bone stock.

Periprosthetic bone loss is a major cause for concern in patients undergoing total hip arthroplasty (THA). There are many different factors that may determine the pattern of bone loss and bone remodelling following THA, such as the quality of the bone before the hip replacement, skeletal bone mass at the time of the operation, material and method of fixation and implant design. Recent developments in dual-energy X-ray absorptiometry (DXA) have made it possible to quantify bone mineral density (BMD) to evaluate changes around the prosthesis and to measure bone stock and bone density redistribution after a total hip replacement. In this cross-sectional multicentre clinical study the DXA method was used to compare bone mass after uncemented THA of a custom-made stemless design with five groups of conventional cementless implants (Alloclassic, Mayo, CFP, IPS, ABG). The adaptive bone changes of the proximal femur three years after implantation were evaluated. Periprosthetic BMD was measured in 130 subjects in the seven regions of interest (ROI) based on Gruen zones. Significant differences were found between the stemless implant and the other five groups in zones 1, 4 and 7. The CFP, IPS, and ABG groups showed decreased BMD in ROI 1, and the Mayo, IPS and Alloclassic in ROI 7. An increased BMD in ROI 4 was observed in the Mayo, IPS, ABG and Alloclassic groups. The results of the present study suggest that a conservative stemless implant with complete proximal load transfer produces a homogeneous and more physiological redistribution of bone density, allowing maintenance of proximal periprosthetic bone stock.