A metallic hemiarthroplasty resurfacing prosthesis for the hallux metatarsophalangeal joint.

Two-hundred seventy-nine arthritic hallux metatarsophalangeal joints treated surgically with a metallic resurfacing hemiarthroplasty over a 40-year period were reviewed. The implant, which is made available in three evenly graded sizes, is designed to replace only the articular surface of the proximal phalanx, with minimal resection of bone stock. The pathologic indications for surgery included classical hallux rigidus, rheumatoid arthritis, and degenerative changes associated with hallux valgus and bunion deformity. Follow-up at 8 months to 33 years after surgery revealed good or excellent clinical results in 95%. The time to follow-up was in excess of 5 years in 101 (36%) of the procedures, beyond 10 years in 62 (22%), and longer than 20 years in 23 (8%). Unlike other available surgical options for this debilitating condition, biomechanics of the hallux metatarsophalangeal joint remained unaffected and problems associated with prosthetic wear or mechanical failure were not encountered.

Total knee arthroplasty. A personal retrospective and prospective review.

The author's current concepts of total knee arthroplasty evolved from the design and subsequent 20 years' experience with a metallic tibial plate in more than 170 knees between 1953 and 1972. The rationale for this resurfacing device and, later on, for the development of the author's total knee replacement ensemble was based on certain basic principles that were directed to the preservation of bone stock and the reconstitution of the normal knee joint modalities. Sixteen subsequent years of personal experience in the implantation of more than 1700 total knee replacements commencing in 1972, using both cemented and uncemented fixation technique, have clearly established the direct relationship between the successful results and the degree of precision in the implementation of correct anatomic principles.

The free synovial graft as a shield for collagen ingrowth in cruciate ligament repair.

The anterior cruciate ligament (ACL) was excised bilaterally in the knee joint of three dogs and was replaced in a conventional manner with a composite polyglycolic acid (PGA) and Dacron braided ligament prosthesis. In one knee of each dog, the ligaments were wrapped with a free synovial graft taken from the suprapatellar pouch in an attempt to keep the prosthesis extrasynovial, while the ligaments in the opposite three knees were left uncovered and thus directly exposed to synovial fluid. The dogs were killed at approximately one year postoperation, and microscopic sections of all ligaments were taken. The three knees with the synovial sheath showed a significantly greater bulk of fibrous tissue along the ligament scaffold grossly and a greater abundance of collagen producing cells microscopically, compared to the unwrapped ligaments. The gross and microscopic findings were identical in each of the three knees with the covered ligaments and were equally consistent in the three that had been left unprotected from the synovial fluid. These findings suggest that a free synovial graft may simulate the normal protective role of the synovial membrane and allow and/or induce collagen ingrowth in synthetic or autogeneic tissue stints for the repair of acute cruciate ligament tears.

The anatomic total knee resurfacing arthroplasty.

The long-term results of total knee arthroplasty are largely dependent on the degree to which the implants and the technique for their insertion duplicate the normal joint anatomy, mechanics, and kinematics. Aberrations in these modalities, occasioned by technical malalignment of the joint or by nonanatomic designing, sizing, or positioning of the implants, are the predominant causes of postoperative limitation of motion and loosening of the implants. Although inadequacies in the bonding effect of cement and in the structural strength of polyethylene have been cited as contributing factors in the incidence of loosening of the tibial component, this complication occurred in less than 2% of 532 cemented Anatomic Total Knee (ATK) replacements that were available for review at a follow-up period of two to 11 years. The long-term follow-up results, based on pain relief, motion, and level of activity, were judged excellent or good in 89% of the knees. Problems related to the patella and loosening of the tibial component were the predominant mechanical complications that required revision. The incidence of loosening was routinely related to technical malalignment of the knee joint or the prosthesis. However, experimental and recent clinical studies indicate that porous-surfaced implants may provide a more durable and long-lasting mode of stabilization. Except for the adaptation of the implants to the porous-coated, noncemented technique, the ATK arthroplasty ensemble has remained essentially unchanged from the original 1972 design.