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Biomedical subjects

W C Head

Publications and source records attributed to W C Head.

52 records · Page 3Linked to original sources
PubMed1991

Comparison of the early healing course of porous titanium with hydroxyapatite-coated porous titanium hip implants: clinical considerations for the use of hydroxyapatite coating in total hip replacement.

The role of hydroxyapatite (HA) coating in the fixation of human total joint prostheses remains to be established. Results of animal studies have been favorable, showing very rapid bone formation with a corresponding increase in bone-implant bond strength. In addition, the quantity of bone may be increased. This study compared identical porous titanium primary total hip implants with and without HA in similar patient populations. All of these patients were healthy and reliable, and had optimal bone geometry and bone quality for cementless fixation. The purpose of the study was to contrast the sequence of events, in the first year after surgery, between the two implant groups to identify the contribution of HA to early patient function and early radiographic appearance of the prosthesis. No significant clinical difference could be demonstrated between the two groups at 1 year from surgery. However, the HA group progressed more rapidly when comparing clinical scores at 6 months (P = .0058), and appeared to demonstrate more rapid bone remodeling at 6 months on the femoral side, although this observation did not quite make statistical significance (P = .0618). There was no difference between the acetabular components during the course of this study.

Female↗
PubMed1991

Failure mechanisms of unicompartmental knee replacement: the impact of changes in operative technique and component design.

Reliable unicompartmental knee replacement requires knowledge of the common failure mechanisms of this type of arthroplasty. The problem in the past has been loosening of components because of design flaws and technical failure. Whereas recent reports are very encouraging in terms of clinical results and enhanced durability of unicompartmental replacements, the current study confirms the observation that nonparallel orientation of femoral and tibial components is common and may produce excessive polyethylene wear and clinical failure. Newer unicompartmental designs with meniscal bearings may be the answer to this problem.

Evaluation Studies as Topic↗
PubMed1990

Massive allografts in salvage revisions of failed total knee arthroplasties.

Ten patients with failed total knee arthroplasties and severe bone loss were treated with massive whole distal femur and proximal tibial allografts in combination with prosthetic implants. Fourteen allografts were inserted either as invaginated or segmental grafts and were rigidly fixed to the host bone. Clinically and roentgenographically, 12 of 14 grafts (86%) seemed to have united to the host bone. The average range of motion was 92 degrees. Five patients developed complications; two of these involved the allograft (nonunion and fracture) and two were caused by inadequate healing at the ligament-allograft junction. One patient had a late infection. With careful planning and improved surgical techniques, these complications can be avoided. The massive allograft-prosthesis composite techniques is a viable reconstructive alternative worthy of further clinical trials.

Aged↗
PubMed1990

Reconstruction of patellar tendon rupture after total knee arthroplasty with an extensor mechanism allograft.

Although patellar tendon rupture after total knee arthroplasty (TKA) is a rare complication, the consistently poor outcome of conventional tendon repair has convinced some to abandon such reconstruction in favor of a prospective protocol using an allograft distal extensor mechanism. The graft consists of a quadriceps tendon, a patella with a cemented prosthesis, a patellar tendon, and a tibial tubercle. Since December 1985, 13 knees in 12 patients were reconstructed using this method. Ten knees were followed for six to 51 months; five of these knees were followed for more than 24 months. Knee extension power and improved function were ultimately attained in all cases, although minimal extensor lags were present in three cases. Preoperative motion returned in all but one knee. Healing of the allograft to the host tissue was attained primarily at all of the tibial junctions. Two graft complications occurred, both in the first three months after surgery: one quadriceps junction treated by resuture failed at the one-month mark, and the other graft had to be revised for extensor weakness from rupture of the graft at the patella-patellar tendon junction, which was attributed to surgical damage to the tendon. After completion of healing to the host and rehabilitation of the knee joint, no grafts in the series failed during the course of normal daily activities. One patient fractured the allograft patella in a severe fall. The long-term durability of this construct needs to be studied further.

Aged↗
PubMed1989

Noncemented acetabular revision arthroplasty using allograft bone.

The authors retrospectively reviewed a series of 106 acetabular revisions for failed cemented total hip arthroplasties followed from 12 to 56 months. All of the sockets had extensive bone deficiency requiring bone graft surgery. The deficiencies were classified as cavitary, combined cavitary and segmental, and pelvic discontinuity. The purpose was to evaluate clinical experience with three different acetabular components. In chronological order, the three components tested were bipolar type, truncated-cone screw-in type, and porous-coated titanium press-fit type with fins. These were combined with four different bone augmentation constructs, using nonstructural morselized fresh-frozen allograft or segmental freeze-dried allograft. Follow-up evaluation of both the bipolar and screw-in designs showed frequent migration with bone graft resorption, compromising the clinical scores and leading to some revisions. The press-fit design had little migration, reliable graft healing, and better clinical scores. No revisions have been done. The nonstructural morselized bone allograft fared better under stable cups. The large segmental grafts did much better when buttress plating was combined with interfragmentary screw fixation compared to screws alone.

Acetabulum↗
PubMed1987

Extensile exposure of the hip for revision arthroplasty.

The authors describe a lateral approach to the hip without trochanteric osteotomy that allows sufficient access to the femur and acetabulum for revision total hip arthroplasty. When bone loss is extensive, this approach permits massive autograft/allograft arthroplasty of the proximal femur and acetabulum. This approach follows anatomic muscle planes, maintains abductor function, and allows wound closure with a viable muscle cuff around the acetabulum and upper femur. The exposure is adequate for anatomic placement of components and correction of leg length discrepancy.

Follow-Up Studies↗
PubMed1987

Proximal femoral allografts in revision total hip arthroplasty.

Patients with total hip arthroplasty (THA) and aseptic loosening associated with severe bone deficiency were treated with freeze-dried bone allografts of the proximal one-third of the femur. Twenty-two of the first 25 patients were available for review with an average follow-up period of 28 months. Significant functional improvement was obtained in 16 patients (73%). The following complications occurred with allograft revisions: dislocation, wound hematoma, joint instability, nonunion, implant failure, and acetabular loosening. Nine patients required additional surgical procedures. There have been no infections or rapid lysis indicative of an allograft rejection phenomenon. The 73% success at the two-year postoperative interval of incorporation of freeze-dried allografts for salvage situations has been encouraging. However, the long-term durability of these grafts is not known and will require further follow-up study.

Adult↗
PubMed1987

Freeze-dried proximal femur allografts in revision total hip arthroplasty. A preliminary report.

Failure of cemented total hip arthroplasty can emerge from several causes and may be associated with severe bone loss in the proximal femur with a marked diminution in functional capacity of the limb. This is a preliminary report of 14 patients with revision operations for failed total hip arthroplasty. Freeze-dried allograft bone ws implanted for restoration of extensive bone loss in the proximal for restoration of extensive bone loss in the proximal femur. All 14 patients were operated on to salvage failed cemented total hip arthroplasties. Allografts were employed only for large proximal femoral deficiencies. In these patients the alternatives were either an unstable excision arthroplasty or a femoral deficient prosthesis. After revision, all patients had complete bony union and ambulated with the assistance of a cane with greatly increased function and pain relief. There were no infection. Functionally, the patients have shown marked improvement. At this time there is no radiologic evidence of resorption of the graft. The use of bone allografts in this procedure has been encouraging to date; however, the follow-up period has been only 16-30 months. the success or failure of this procedure will be determined in time.

Adult↗
PubMed1984

Total articular resurfacing arthroplasty. Analysis of component failure in sixty-seven hips.

Total articular resurfacing arthroplasty with the Tara device was performed on sixty-seven hips in sixty-three patients from 1978 to 1981. I analyzed the results, paying particular attention to prosthetic failure. Loosening of the femoral component occurred in one hip and loosening of the acetabular component, in seven hips. All eight required revision to conventional total hip replacement. Fifteen other patients in the series had radiographic evidence of component failure but have had no significant pain to date. They were regarded as having impending failure. Four of the fifteen showed significant stress-shielding on the femoral side, two with simultaneous acetabular lucency at the bone-cement interface. The other eleven showed progressive acetabular lucency. The total anticipated failure rate was 34.3 per cent (11.9 per cent definite and 22.4 per cent anticipated). The ages of the patients at surgery averaged 49.1 years in the actual failure group and 34.2 years in the impending failure group. Factors that may have been responsible for the unacceptably high incidence of component failure include the young age of the patients in whom this operation was performed and their high activity level. Additional reasons for mechanical failure (both definite and anticipated) on the acetabular side include poor cement distribution with resultant micromotion and increased frictional torque with the larger-diameter component of the prosthesis.

Adolescent↗
PubMed1982

The Wagner surface replacement arthroplasty.

The Wagner resurfacing arthroplasty was designed to provide a more conservative means of treatment for patients with debilitating hip disease, while at the same time providing functional results similar to those of conventional total hip arthroplasty. The Wagner procedure is conservative on the femoral side, as it is successful in preserving the head and neck while providing options for salvage should the system fail. The design of the acetabular component, however, makes revision most difficult because of sacrifice of a relatively large surface area of bone that is necessary for implantation with the Wagner device. If the acetabular component fails, there is further destruction of bone that severely compromises revision surgery. Although the basic design premise of closely simulating the normal anatomy of the hip is sound, the results in this series do not support the long-term stability of such a system at the present time.

Acetabulum↗
PubMed1981

Wagner surface replacement arthroplasty of the hip. Analysis of fourteen failures in forty-one hips.

Wagner resurfacing arthroplasty of the hip was performed on forty-one hips in forty patients from 1977 to 1979. Results were analyzed with particular attention to prosthetic failures, which occurred in fourteen hips. Loosening of the femoral component occurred in five hips; loosening of both the femoral and the acetabular component, in two hips; loosening of the acetabular component, in two hips; loosening of the acetabular component, in two hips; avascular necrosis of the femoral head (with no concomitant femoral-component loosening), in two hips; and femoral neck fracture, in three hips. Time to failure averaged eighteen months (range, three months to two and one-half years). The over-all failure rate of 34 per cent is considered unacceptably high and therefore I do not recommend the Wagner arthroplasty for routine use. Factors tht may be responsible for the increased failure rate include a high susceptibility to avascular necrosis of the femoral head, the younger age of patients in whom this operation is performed, and the biomechanical design properties of the prosthesis.

Adolescent↗
PubMed1977

A versatile surgical approach to the hip.

A versatile surgical approach to the hip is presented which allows for total accessibility to the anterior, the lateral, or the posterior aspect of the hip through a single skin and fascial incision. The approach through an S-shaped incision is recommended for total hip replacement arthroplasty, femoral head replacement, hip nailings, fracture dislocations of the hip, and sciatic nerve explorations.

Arthroplasty↗
PubMed1977

Ipsilateral hip and knee replacements as a single surgical procedure.

A total of thirteen surgical procedures were performed on eight patients, all of whom had a history of rheumatoid arthritis. Five patients had bilateral hip and knee replacements and three patients had ipsilateral hip and knee replacements for a total of twenty-six joint replacements. Ambulatory status for all patients was significantly improved and all patients subjectively reported a great reduction in pain postoperatively. Complications included two transient peroneal-nerve palsies in the same patient from which she recovered spontaneously, and one questionable pulmonary embolus which resolved with heparin therapy. The relative advantages of this type of procedure and the indications for and against surgery are discussed.

Adult↗
PubMedDate not supplied

Autologous transfusion following frozen storage at -85 degrees.

Two cases are presented in which frozen autologous blood stored at -85 degrees was used in surgical autologous transfusions. No complications were encountered in either patient intraoperatively or postoperatively. At the time of discharge hemoglobin and hematocrit were normal. Frozen autologous blood is recommended when more than 4 units of blood are required; it is particularly useful when crossmatching is not possible owing to presence of antibodies in the blood.

Aged↗