Parthiv Rathod

Large diameter heads

Large femoral heads have been used with increasing frequency over the last decade. The prime reason is likely the effect of large heads on stability. The larger head neck ratio, combined with the increased jump distance of larger heads result in a greater arc of impingement free motion, and greater resistance to dislocation in a provocative position. Multiple studies have demonstrated clear clinical efficacy in diminishing dislocation rates with the use of large femoral heads. With crosslinked polyethylene, wear has been shown to be equivalent between larger and smaller heads. However, the stability advantages of increasing diameter beyond 38 mm have not been clearly demonstrated. More importantly, recent data implicates large heads in the increasing prevalence of groin pain and psoas impingement. There are clear benefits with larger femoral head diameters, but the advantages of diameters beyond 38 mm have not yet been demonstrated clinically.

Similar improvement in gait parameters following direct anterior & posterior approach total hip arthroplasty.

We compared gait parameters prior to, at 6 months and 1 year following total hip arthroplasty (THA) performed via direct anterior approach (DAA) and posterior approach (PA) by a single surgeon in 22 patients. A gait analysis system involving reflective markers, infrared cameras and a multicomponent force plate was utilized. Postoperatively, the study cohort demonstrated improvement in flexion/extension range of motion (ROM) (P = 0.001), peak flexion (P = 0.005) and extension (P = 0.002) moments with no differences between groups. Internal/external ROM improved significantly in the DAA group (P = 0.04) with no change in the PA group. THA performed via DAA and PA offers similar improvement in gait parameters with the exception of internal/external ROM which might be related to the release and repair of external rotators during PA THA.

A Randomized, Controlled, Prospective Study Evaluating the Effect of Patellar Eversion on Functional Outcomes in Primary Total Knee Arthroplasty

BACKGROUND Patellar mobilization technique during total knee arthroplasty has been debated, with some suggesting that lateral retraction, rather than eversion, of the patella may be beneficial. We hypothesized that patients with knees surgically exposed using patellar lateral retraction would have comparable outcomes with patients with knees surgically exposed using patellar eversion. METHODS After an a priori power analysis, 120 patients with degenerative arthrosis were prospectively enrolled and were randomized to one of two patellar exposure techniques during the primary total knee arthroplasty: lateral retraction or eversion. The primary outcome measure was one-year, dynamometer-measured quadriceps strength. The secondary outcome measures evaluated during hospital stay included the ability to straight-leg raise, visual analog scale in pain, walking distance, and length of stay. The secondary outcome measures that were evaluated preoperatively and through a one-year follow-up included the Short Form-36 Physical Component Summary and Mental Component Summary scores, range of motion, quadriceps strength, and radiographic rate of patella baja and tilt. RESULTS A mixed-model analysis of variance showed no significant differences between the two groups in the one-year outcome measures. At one year postoperatively, quadriceps strength was not different between groups (p = 0.77), and the range of motion significantly improved (p < 0.01) from preoperative values by a mean value (and standard deviation) of 6° ± 17°, with no significant difference (p = 0.60) between groups. The Short Form-36 Physical Component Summary score and Mental Component Summary score significantly improved (p < 0.01) for both study groups from preoperatively to one year postoperatively with no significantly different effects between groups (time × group, p = 0.85 for the Physical Component Summary score and p = 0.71 for the Mental Component Summary score), and the scores were not different at one year after surgery. There were no significant differences between groups in the change in frequency of the radiographic patella baja (p = 0.99) or the radiographic patellar tilt (p = 0.77) from before surgery to one year after surgery. CONCLUSIONS Lateral retraction of the patella did not lead to superior postoperative results compared with eversion of the patella during total knee arthroplasty as evaluated using our primary outcome measure of one-year, dynamometer-measured quadriceps strength or our secondary outcome measures. LEVEL OF-EVIDENCE Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Early Failure of a Ceramic-on-Metal Total Hip Arthroplasty

The total hip arthroplasty procedure has improved substantially over the past two decades, including the design, materials used, and the fixation. Minimizing bearing surface wear has become a determinant of long-term implant survival. Approaches to minimize bearing surface wear have included improvement in polyethylene as well as the introduction of hard-on-hard bearing couples. Presently, the most commonly used hard bearing surfaces include metal-on-metal (MOM) and ceramic-on-ceramic (COC) couples. Both have excellent tribological properties, but they also have limitations. Second-generation MOM articulations have lower wear rates compared with metal-on-ultra-high-molecular-weight polyethylene (UHMWPE)1-3. However, despite lower volumetric wear, the wear particles are very small and their presence locally and systemically is concerning4-11. COC articulations have better wear properties than MOM and UHMWPE couples12-17, but issues such as squeaking18,19 and implant fracture remain problematic16,20,21. In the hope of overcoming the adverse issues of MOM and COC bearing couples, an innovative ceramic-on-metal (COM) articulation, utilizing a ceramic head and metal liner, has been recently introduced. Proposed advantages of COM couples include reduced wear, with resultant lower serum metal ion levels compared with MOM12,17,22-24, although COM and COC couples have similar wear rates12,24,25. Adverse soft-tissue reactions are a well-known complication of MOM hip resurfacing arthroplasty7,26-28 as well as contemporary MOM total hip arthroplasty29,30. Such soft-tissue reactions have not been reported with COM bearings; however, these devices have had limited use and only short-term follow-up. We report the case of a patient who experienced early failure of a COM total hip arthroplasty. The patient was informed that data concerning her case would be …