Improvements in prosthetic materials, designs, and implant fixation for THA have led to bearing surface wear being the limitation of this technology. Hard-on-hard bearings promise decreased wear rates and increased survival. However, there may be different survival rates based on bearing materials, manufacturing technologies, and femoral component designs. Additionally, survival rate variability may be based on study design.
Dislocation remains a serious complication in hip arthroplasty. Resurfacing proponents tout anatomic femoral head restoration as an advantage over total hip arthroplasty. However, advances in bearings have expanded prosthetic head options from traditional sizes of 22, 26, 28, and 32 mm to diameters as large as 60 mm. Large heads reportedly enhance stability owing to increased range of motion before impingement and increased jump distance to subluxation. Available larger diameter material combinations include metal- or ceramic-on-highly crosslinked polyethylene and metal-on-metal, each with distinct advantages and disadvantages.
Various clinical and biomechanical studies suggest certain acetabular positions may be associated with higher wear and failure rates in modern metal-on-metal hip resurfacing arthroplasties. However, there are no widely available, reliable, and cost-effective surgical techniques that ensure surgeons are able to place an acetabular component within the safe range of inclination angles after hip resurfacing surgeries.
Reports in the literature have linked high acetabular inclination angles to increased wear of ceramic-on-ceramic bearings. However, many of these studies were only conducted in vitro and did not address the clinical relevance of such findings.
High survival has been reported for resurfacing arthroplasty in patients with femoral deformities. Also, hardware removal may not always be necessary with resurfacing arthroplasty and may eliminate some of the difficulties performing total hip arthroplasty (THA) in patients with posttraumatic osteoarthritis.
The direct anterior approach (DAA) for hip resurfacing arthroplasty is a technically difficult approach but theoretically reduces the soft tissue trauma to the hip because it does not require muscle detachments from the bone. Furthermore, the patient is in the supine position facilitating fluoroscopy to control component placement. However, the complications associated with the learning curve and functional outcome scores are not well defined in the literature.
Young patients with osteonecrosis (ON) treated with THA often have suboptimal function and radiographic failure with eventual revision. Resurfacing may be an option because of potentially increased functionality and decreased radiographic failure, although neither has been confirmed in the literature.
Is Mid-head Resection a Durable Conservative Option in the Presence of Poor Femoral Bone Quality and Distorted Anatomy?
High medium-term survivorship of hip resurfacing arthroplasty in young patients has led to its increased usage. To achieve high survival rates, selecting patients with appropriate proximal femoral morphology and bone quality is important. For patients with poor bone quality or abnormal morphology, the mid-head resection technique is an alternative, bone-conserving procedure but whether this technique results in acceptable complications and survival is unknown.
Squeaking is reportedly a complication in patients having ceramic-on-ceramic total hip implants. The etiology remains unknown and multifactorial with recent studies suggesting a relationship between the audible squeak and implant design. When we evaluated our ceramic-on-ceramic cohort, we noticed squeaking primarily in patients receiving an acetabular system designed with an elevated titanium rim.
High rates of heterotopic ossification have been associated with hip resurfacing as compared to THA. Bone debris from femoral head reamings is cited as one of the risk factors linked to increased rates of heterotopic ossification.
Heterotopic ossification (HO) is a concern for patients undergoing hip surgery, especially surface replacement arthroplasty (SRA) who tend to be younger, more active, and anticipate good motion. It is unclear, however, whether HO occurs more frequently after SRA than traditional total hip arthroplasty (THA) and whether aspirin influences the risk.
Femoral neck fracture in hip resurfacing has been attributed to technical error during femoral head preparation. In the absence of fracture, several radiographic findings have been speculated to increase the risk of femoral component failure.
Short-term studies report comparable complication rates of one-stage bilateral versus two-stage procedures in hip resurfacing, although the long-term effects of such procedures on survivorship, quality of life, and disease-specific scores are currently unknown.
Metal-on-metal bearings in surface arthroplasty are associated with prolonged periods of elevated ion circulation. However, there exists some controversy regarding the effect of different surgical variables on the concentration of metal ions in whole blood of patients after hip resurfacing.
Metal-on-metal articulations can release substantial amounts of particles containing cobalt and chromium into the surrounding milieu, causing concern for cellular toxicity and adverse local soft tissue reactions. The diameter of the femoral head has been one of the variables that inversely affects wear of metal-on-metal total hip arthroplasty (THA). The oxidative stress of increased metal ions can be measured with serum markers. It is still controversial if larger femoral head diameters decrease wear rates in patients with metal-on-metal THA and if the increased metal ions alter the body’s antioxidant status.
Metal ions released from arthroplasty devices are largely cleared in urine, leading to high exposure in renal tissues. Validated early markers of renal damage are routinely used to monitor workers in heavy metal industries, and renal risk can be quantified in these industries. It is unclear if the ion levels in patients with metal-on-metal hips are sufficient to cause renal damage.
Functional Recovery Period after Arthroscopic Rotator Cuff Repair: Is it Predictable Before Surgery?
Several studies have reported functional recovery of the shoulder after arthroscopic rotator cuff repair (ARCR). Preoperative estimation of the time required for functional recovery is important for determining surgical indications and for planning timing of the surgery and an appropriate postoperative physical therapy.
Previous studies reporting the impact of osteoarthritis (OA) on pain and function after hip arthroscopy largely predate resection of femoroacetabular impingement (FAI).
Pelvic radiographs are helpful in assessing limb-length discrepancy (LLD) before and after THA but are subject to variation. Different methods are used to determine LLDs. As a pelvic reference, both ischial tuberosities and the teardrops are used, and as a femoral reference, the lesser trochanter and center of the femoral head are used.
CT allows for accurate measurement of acetabular orientation and shape, but malpositioning of the pelvis may lead to measurement variance.
A combination mechanical-pharmacologic regimen is an accepted prophylactic treatment against symptomatic venous thromboembolism for patients undergoing total hip and knee arthroplasties. Foot pumps have been recognized as effective mechanical devices. Research suggests pharmacologic prophylaxis for venous thromboembolism is associated with complications and foot pumps offer an adjunct or alternative approach. Presumably the effectiveness of foot pumps relate to enhancement of venous flow.
Some commercial simulators are available for training basic arthroscopic skills. However, it is unclear if these simulators allow training for their intended purposes and whether the perception of usefulness relates to level of experience.
Posterior-stabilized TKAs, which use a polyethylene tibial post to articulate against a metal femoral cam, are used regularly. Reported complications are related to the patellofemoral articulation or the tibial post-cam mechanism. Fracture of the tibial post is an uncommon but disabling complication after posterior-stabilized TKA that requires operative treatment.
Studies of minimally invasive surgery (MIS) approaches to TKA have shown decreased postoperative pain, earlier return to function, and shorter lengths of stay in the hospital. However, it is unclear whether these differences translate into decreased costs or charges associated with care.
Total ankle arthroplasty (TAA) implantation is increasing, as the potential for pain relief and restoration of function and risks are compared with those for ankle fusion. A previous analysis with a simple decision tree suggested TAA was cost-effective compared with ankle fusion. However, reevaluation is warranted with the availability of newer, more costly implants and longer-term patient followup data.
The iliocapsularis muscle is a little known muscle overlying the anterior hip capsule postulated to function as a stabilizer of dysplastic hips. Theoretically, this muscle would be hypertrophied in dysplastic hips and, conversely, atrophied in stable and well-constrained hips. However, these observations have not been confirmed and the true function of this muscle remains unknown.
Although a wide variety of acetabular deformities in developmental dysplasia of the hip (DDH) have been reported, the morphologic features of the entire pelvis in DDH are not well characterized and their correlation with acetabular deformity is unknown.
Pelvic Rotation and Tilt Can Cause Misinterpretation of the Acetabular Index Measured on Radiographs
Radiographic diagnosis and followup studies of developmental dysplasia of the hip are commonly performed by measuring the acetabular index on radiographs using Hilgenreiner’s method. The outcome of the measurement, however, depends on the orientation of the subject’s pelvis relative to the xray source. The influence of pelvic rotation and tilt on the measurement error has been evaluated separately but not in combination.
Web-based questionnaires have become popular, however, access to the Internet can be biased regarding age, gender, and education, among other factors. Therefore, it is unknown whether this is a reasonable avenue to administer a questionnaire to patients or whether Web-based can be a reliable alternative to paper-based.
2010 Mid-America Orthopaedic Association Physician in Training Award: Healing Complications Are Common After Locked Plating for Distal Femur Fractures
Several mechanical studies suggest locking plate constructs may inhibit callus necessary for healing of distal femur fractures. However, the rate of nonunion and factors associated with nonunion are not well established.
Corrective osteotomy using dorsal plates and structural bone graft usually has been used for treating symptomatic distal radius malunions. However, the procedure is technically demanding and requires an extensive dorsal approach. Residual deformity is a relatively frequent complication of this technique.
Patients have high reinjury rates after ACL reconstruction. Small knee flexion angles and large peak posterior ground reaction forces in landing tasks increase ACL loading.
Recent advances in technology and the use of image archiving and communication systems (PACS) has led some institutions to abandon conventional plain film radiography and rely solely on digital computed radiography. The level of accuracy of digital radiography in measuring distances for orthopaedic applications is unclear.
Abnormal development and growth of the capital femoral epiphysis and acetabulum are associated with a wide variety of underlying etiologies, one of which is Legg-Calvé-Perthes disease.
Muscle atrophy impacts almost every patient seen for orthopaedic conditions. Unfortunately, no effective treatment is available to date. Matrix metalloproteinases (MMPs), especially MMP-2, are involved in skeletal muscle atrophy. MMP-2 null mice reportedly have substantially reduced muscle atrophy after tendon transection compared with wild-type mice, suggesting MMP-2 plays an important role in muscle atrophy. Although the exact mechanisms remain unknown, a newly-discovered intracellular form of MMP-2 suggests a possible novel mechanism of MMP-2 digesting muscle matrix during muscle atrophy. I propose a new pharmacologic treatment for muscle atrophy using selective MMP-2 inhibitors.