Is there still a role for threaded acetabular cups?

INTRODUCTION:

Total hip arthroplasty (THA) is 1 of the most common procedures in orthopaedic surgery. Different options and implants are currently available. Uncemented hip cups need primary stability for bone ingrowth, the use of screws is required when the desired stability is not achieved. Another option is the use of a hemispherical threaded cup with enhanced primary stability. The purpose of our study was to compare the results of a 3rd-generation threaded cup versus a press-fit cup with a long track record.

MATERIALS AND METHODS:

A consecutive series of 300 THAs performed by 2 surgeons was retrospectively reviewed, 150 press-fit cups and 150 screwed cups. Minimum follow-up 27 months; maximum 78 months (mean 52.5 months). The primary endpoint was a stable and painless THA, secondary endpoints included Hip disability and Osteoarthritis Outcome Score, Junior and radiographic evaluation.

RESULTS:

Preliminary results showed no statistically significant differences between the 2 groups for all the evaluated parameters, the number of early mechanical loosening was higher for press-fit cups, but this value was not statistically significant. At a mean follow-up of 52.5 months 1 cup revision (0.3%) was seen in the screwed cup group and 2 (0.6%) in the press-fit cup; these results were not statistically significant.

DISCUSSION AND CONCLUSION:

The main concern for screwed cups is the greater bone loss and possible removal difficulties during revision surgery. This study has some limitations, in particular regarding follow-up, but is still ongoing. Our results showed no difference between the 2 systems.

A randomized double-blind clinical trial on the treatment of knee osteoarthritis: the efficacy of polynucleotides compared to standard hyaluronian viscosupplementation

BACKGROUND

This randomized, double-blind, parallel-group clinical trial aims to assess the equivalence of intra-articular polynucleotides compared to standard hyaluronic acid (HA) viscosupplementation in the treatment of knee osteoarthritis (OA).

METHODS

75 patients affected by knee OA were assessed for eligibility and 72 were enrolled and randomized to receive either intra-articular polynucleotides (Condrotide-36 patients) or hyaluronic acid (Hyalubrix-36 patients) at the Orthopedic Institute "Gaetano Pini" (Milan). All patients underwent three intra-articular injections of Condrotide or Hyalubrix with an interval of 1week. Participants, care givers, and investigators responsible for outcome assessment were all blinded to group assignment. Primary outcome measurements (KOOS and pain level (1) at rest, (2) at weight-bearing and (3) during physical activity) were evaluated at baseline (T0) and after one (T1), two (T2), six (T6), ten (T10), and 26 (T26)weeks. Secondary measurements included the determination of COMP serum levels at T0, T6 and T26.

RESULTS

The reduction of pain and the increase of KOOS values from baseline were statistically significant for both treatments; nevertheless, for parameter KOOS "symptoms" the treatment with Condrotide showed significant results already after twoweeks (at T2 p=0.003) while the results obtained with Hyalubrix became significant only after 18 weeks (at T18 p=0.01). No significant adverse events were reported.

CONCLUSIONS

Condrotide is as effective as Hyalubrix in reducing knee OA symptoms but showed an earlier response on pain reduction and can therefore be considered a valid alternative to the use of HA in the treatment of OA, avoiding the adverse events of NSAIDs and of intra-articular corticosteroids.