Lars Weidenhielm

Revision Hip Arthroplasty with the Use of Cement and Impaction Grafting. Histological Analysis of Four Cases

The findings of radiographic studies have suggested that the cementing of an implant with a polished tapered stem into a bed of impacted bone allograft may provide adequate function of the joint and may restore bone in the proximal part of the femur. However, radiographs of hips with cancellous bone graft adjacent to cement are difficult to interpret, and the viability of impacted bone graft that is adjacent to cement and its capability for remodeling are unclear. To evaluate this interface further, we obtained biopsy specimens from the proximal part of the femur at the time of removal of trochanteric wires from four patients eleven to twenty-seven months after revision hip arthroplasty with cement and impaction grafting. Three relatively ill defined zones were identified histologically: an inner zone consisting of bone cement, fibrous tissue, and partially necrotic trabeculae with evidence of bone-remodeling; a middle zone consisting of viable trabecular bone and probable formation of so-called neocortex with fewer particles of bone cement; and an outer zone consisting of viable cortex. Fibrous tissue was present around some of the incorporating fragments of bone graft, but no continuous fibrous membrane was seen. Particles of cement were identified, but no polyethylene debris was visible on examination with light microscopy. The results demonstrated remodeling of bone and at least partial restoration of bone stock in the proximal part of the femur after revision arthroplasty with cement and impaction grafting.

Complex cemented revision using polished stem and morselized allograft. Minimum 5-years' follow-up.

Abstract The aim of this study was to evaluate the results of complex hip revision using a cemented, collarless and polished femoral stem design (CPT, Zimmer, Warsaw, In.) within a tightly impacted morselized allograft. We have now been using the impaction grafting technique in combination with the CPT stem (Zimmer) for 10 years in complex cases of severe bone loss. In this study we have elected to report only those patients who have been revised at least once before revision using the impaction grafting technique. All the patients in the study group have a minimum follow-up of 5 years after the impaction grafting revision. In total, 43 consecutive hips in 40 patients, 22 men and 18 women, with a follow-up time of between 5 and 7 years are included in the study. The complications related to the revised hip consist of three early dislocations managed by closed reduction. Two patients suffered from periprosthetic fracture, both managed with plate osteosynthesis. Two cementless sockets were revised due to aseptic socket loosening. The Endoklinik rating of preoperative bone loss for the revised hips was 2 in 13 hips, 3 in 23 hips, and 4 in 7 hips. During the first year 29 stems subsided 2–4 mm within the cement mantle. In 8 cases, a subsidence of 5–9 mm was measured. The subsidence was nonprogressive, and no subsidence occurred after the 1st year. The Charnley, D’Aubigne, Postel scoring (maximum 6 points) for pain improved from 2.2 points preoperatively to 4.4 postoperatively, function from 2.3 to 4.3, and movement from 2.3 to 4.1. In conclusion, the concept of impaction grafting in THR revision in our study has so far proven to be successful with good clinical results at 5 years despite the relatively high early subsidence of the femoral component.

Femoral bone regeneration subsequent to impaction grafting during hip revision : histologic analysis of a human biopsy specimen

Cemented revision with impaction grafting shows encouraging early clinical results; postoperative biopsy specimens taken from the proximal femur in humans have demonstrated viable trabecular and cortical bone. Human radiographic studies also illustrate density changes within the proximal femur, consistent with remodeling of bone-graft. In an animal experiment, bone incorporation was shown in the proximal femur, but graft lysis was reported around the distal portion of the implant. We report on a patient who sustained a traumatic femoral fracture at the level of the tip of the femoral component 27 months after revision with impaction grafting and a collarless polished taper stem. At the time of open reduction and internal fixation of the fracture, we obtained circumferential biopsy specimens from the fracture site. Three distinct zones could be identified histologically: i) an inner zone consisting of bone-cement, fibrous tissue, and partially necrotic trabeculae with evidence of bone remodeling; ii) a middle zone consisting of viable trabecular bone and probable neocortex formation with fewer particles of bone-cement; and iii) an outer zone with viable cortex. Fibrous tissue was present around some of the incorporating bone-graft fragments, but no continuous fibrous membrane was present. Cement particles were identified, but no polyethylene debris was found by light microscopy. Biopsy specimens from the distal aspect of the prosthesis may not reflect changes seen proximally, but based on the available tissue, this case illustrated histological evidence of bone-graft remodeling after impaction grafting. These results are consistent with our expectations based on radiographic findings and clinical results.

Cemented collarless (Exeter-CPT) versus cementless collarless (PCA) femoral components. A 2- to 14-year follow-up evaluation.

The purpose of this study was to compare the intermediate results of total hp arthroplasty with a cemented, collarless, femoral prosthesis design (Exeter, Howmedica, Middlesex, UK and CPT, Zimmer, Warsaw, IN) with those of a cementless, collarless, porous-coated femoral component (PCA, Howmedica). A total of 151 hips in 128 patients were reviewed. In the cemented group, 85 Exeter-CPT prostheses were used in 71 patients with an average follow-up period of 6.5 years. In the uncemented group, 66 PCA prostheses were placed in 57 patients with an average follow-up period of 7 years. Harrington hip scores improved from 50.1 to 80.7 for the PCA group and from 49.5 to 87.3 for the Exeter-CPT group. The patient satisfaction rates were 89 and 96%, respectively. Sixty-eight patients with Exeter or CPT prostheses had excellent function and no significant thigh pain after 2 years. One Exeter stem was revised 10 years after the primary surgery because of aseptic osteolysis due to cement defect. Two Exeter sockets were revised because of aseptic loosening. In the PCA group, the incidence of thigh pain that persisted beyond 2 years was 39.4%, and there were high incidences of distal cortical hypertrophy (66.6%) and bead loosening (45.5%). Sixteen hips were revised for aseptic stem loosening of the socket. The cementless ingrowth stems failed earlier (around 5 years), whereas the cemented stems continued to perform well past 14 years. In this study, the cemented, collarless, tapered, femoral prosthesis gave results superior to those of the uncemented collarless, porous-coated anatomic design at an average follow-up period of 7 years (range, 2-14 years).

Surgical correction of leg alignment in unilateral knee osteoarthrosis reduces the load on the hip and knee joint bilaterally.

Seventeen patients with strictly unilateral medial knee osteoarthrosis that justified surgical treatment constituted the study group. No patient had any symptoms from the hip or ankle joints or from the other knee. Eight patients were operated with high tibial osteotomy and nine were operated with unicompartmental prosthetic replacement (Brigham model). The forces and the external moment about the hip, knee, and ankle joints of the involved and uninvolved leg were calculated before and 1 year after corrective surgery and compared to the external moment in 10 normal controls. Clinical examinations was performed and the hip-knee-ankle angle in the involved leg was determined from whole-leg weightbearing radiographs before and 1 year after surgery. The external moments about the hip, knee, and ankle joints and the knee moment arms at mid-stance in the frontal plane during gait were determined with a Kistler force plate and a videorecording system. All patients improved clinically after surgery. The mean hip-knee-ankle angle changed from 11 degrees of varus to 0 degrees. In the uninvolved leg the mid-stance adduction moments about the hip and knee joints were significantly increased compared to normal subjects in the control group before surgery, but reduced to a normal level 1 year after surgery. This reduction was mainly due to a significant reduction of the medially directed force. The moments about the ankle joints were not found to be changed by the knee deformity or by the corrective surgery. RELEVANCE: This study demonstrates that a varus malalignment in the osteoarthrotic knee is accompanied by increased load about the uninvolved hip and knee joint. One might expect a more rapid progression of degenerative changes in joint cartilage as a consequence of such increased load. The reduced load after surgical correction of leg alignment might be beneficial to patients with osteoarthrosis of their hip and knee joints.

Knee motion after tibial osteotomy for arthrosis: Kinematic analysis of 7 patients

The in vivo kinematics of the knee in 7 patients with moderate medial gonarthrosis was analyzed before and 6 months after high tibial osteotomy using roentgen stereophotogrammetric analysis. The inclination of the femorotibial helical axis of rotation did not change with knee flexion or after surgery. The femorotibial rotation increased after surgery. No consistent change in patellar position after surgery was found. Patella translated laterally as the knee was flexed with a maximum patellar translation of about 15 mm and rotated internally with a maximum patellar internal rotation of about 15 degrees. There was no significant change in patellar translation or rotation after surgery. There was a good concordance regarding the size of the tibial wedge removed during surgery, calculated from the Hip-Knee-Ankle radiographs and from the roentgen stereophotogrammetric measurements.

Analysis of the retrieved hip after revision with impaction grafting

Departments of 1Orthopaedic Surgery, Karolinska Hospital, SE-171 76 Stockholm, Sweden, E-mail: lars.weidenhielm@ks.se, 2Orthopaedic Biomedical Engineering Research and Orthopaedic Surgery, Medical College of Ohio, Toledo, Ohio, USA, 3Cumberland Orthopaedics, 1007 South Main St, Crossville, TN 38555, USA, 4Pathology and Orthopaedic Surgery, The Cleveland Clinic Foundation, Cleveland, Ohio, USA Submitted 00-12-28. Accepted 01-04-13