Low-Dose Irradiation and Rotating-Hinge Revision for the Treatment of Severe Idiopathic Arthrofibrosis Following Total Knee Arthroplasty: A Review of 60 Patients With a Mean 6-Year Follow-Up.

BACKGROUND: Severe idiopathic arthrofibrosis after total knee arthroplasty (TKA) is a challenging problem to treat. Low-dose irradiation may decrease fibro-osseous proliferation, while rotating-hinge (RH) revision allows for distal femur shortening and collateral ligament sacrifice. This study reports the clinical outcomes and implant survivorship in patients treated with low-dose irradiation and RH revision for severe idiopathic arthrofibrosis following TKA. METHODS: A retrospective review was performed on 60 consecutive patients. Patients who had greater than 80° arc of knee motion or less than 15° flexion contracture were excluded. Mean follow-up was 6 years (range, 2 to 14). Kaplan-Meier survivorship analyses were performed, and logistic regressions were used to determine associations between preoperative patient characteristics and clinical outcomes. RESULTS: Median flexion contracture and median terminal flexion at presentation were 20 and 70°, respectively; at final follow-up, 59 of 60 patients (98%) had ≤10° flexion contracture and 49 of 60 patients (82%) had ≥90° of flexion. The 10-year survivorship free from reoperation for any reason, revision for any reason, and revision for aseptic loosening were 63, 87, and 97%, respectively. There were 27% percent of patients who underwent a manipulation under anesthesia postoperatively, which was the most common reason for return to the operating room. A greater number of prior surgeries was significantly associated with worse range of motion at the final follow-up (P = .004). There were no known radiation-associated complications. CONCLUSIONS: Patients with severe idiopathic arthrofibrosis following TKA treated with low-dose irradiation and RH revision maintained a gain in knee range of motion of 60° with reliable flexion contracture correction at a mean 6-year follow-up. A manipulation under anesthesia was common in the postoperative period. Survivorship free from revision for aseptic loosening was excellent at 10 years.

A supervisory controller intended to arrest dynamic falls with a wearable cold-gas thruster.

This article examines the feasibility of employing a cold-gas thruster (CGT), intended as a backpack-wearable device, for purposes of arresting backward falls, and in particular describes a supervisory controller that, for some motion described by an arbitrary combination of center-of-mass angle and angular velocity, both detects an impending fall and determines when to initiate thrust in the CGT in order to arrest the impending fall. The CGT prototype and the supervisory controller are described and experimentally assessed using a rocking block apparatus intended to approximate a backward-falling human. In these experiments, the CGT and supervisory controller restored upright stability to the rocking block in all experiment cases that would have otherwise resulted in a fall without the CGT assistance. Since the controller and experiments employ a reduced-order model of a falling human, the authors also conducted a series of simulations intended to examine the extent to which the controller might remain effective in the case of a multi-segment human. The results of these simulations suggest that the CGT controller would be nearly as effective on a multi-segment falling human as on the reduced-order model.

Low-dose Preoperative Unshielded Radiation Is Effective in Heterotopic Ossification Prophylaxis and Does Not Affect Porous Fixation in Total Hip Arthroplasty at 2 Years Minimum Follow-up: A Radiographic Study.

BACKGROUND: Heterotopic ossification (HO) is a frequent complication of total hip arthroplasty (THA). HO can cause pain, limitation of range of motion, and instability. Radiation therapy (RT) for HO prophylaxis is well established but may interfere with early porous ingrowth and pullout strength of implants, as suggested by two animal studies. Although shielding of the bone from irradiation may theoretically protect ingrowth, it has been found to reduce RT effectiveness. Despite the popularity of porous implants in THA, the frequency of HO, and use of RT in its prophylaxis, the effect of RT on porous implant fixation in THA has not been previously reported. At our institution, we use unshielded, single-dose, preoperative 700 to 800 centigrays RT for HO prophylaxis in high-risk patients. We hypothesize that this RT protocol is effective and the press-fit technique protects porous implants during early ingrowth; therefore, long-term implant fixation is not compromised. METHODS: This was a retrospective study aiming to determine fixation of porous THA implants, healing of trochanteric osteotomies, and efficacy of HO prophylaxis with this RT protocol. RESULTS: Thirty-nine patients with follow-up of 24 to 144 months (average 59.7 months) were included. All 26 porous-coated femoral implants (11 revisions and 15 primary) were well fixed. There were 33 porous-coated acetabular implants (18 revisions and 15 primary). Thirty (91%) were well fixed, and three revision implants (9%) demonstrated radiolucent lines in two zones, but patients were clinically asymptomatic. All nine trochanteric osteotomies healed uneventfully. RT provided effective HO prophylaxis in 33 of 39 hips (85%). CONCLUSIONS: Single, low-dose, preoperative RT without shielding does not increase aseptic loosening of porous implants manufactured with plasma porous spray or nonunion of extended trochanteric osteotomies. This protocol provides effective HO prophylaxis in high-risk patients undergoing primary and revision THA.

Porous Femoral Fixation in Total Hip Arthroplasty with Short Anatomical Stem: Radiographic Evaluation.

BACKGROUND: Hip prostheses with short anatomical stems were designed for metaphyseal fixation and to spare bone stock. We present a study of a short anatomical femoral stem used in all age groups of patients with Dorr A and B type of femora. METHODS: We reviewed radiographs of 85 hips in 74 patients who had a cementless total hip arthroplasty with a short anatomical 80 mm femoral stem designed to achieve pure metaphyseal fixation. A ream-only technique was used for femoral canal preparation in all patients. At each follow-up, radiological evaluation was performed for stem alignment, proximal metaphyseal fill, subsidence, status of biological fixation of the femoral stem, heterotrophic ossification, radiolucency, osteolysis, and limb length discrepancy of the stem. Acetabular components were evaluated for positioning, acetabular bone coverage, and radiolucent and osteolytic lesions. RESULTS: The final mean alignment of femoral stem was 2° valgus. The average intramedullary fill by the stem at the proximal level of the lesser trochanter was 93% in the coronal plane and 88% in the sagittal plane. No components were considered to be undersized. Thirteen hips (15.2%) presented radiolucent lines (10 hips < 1 mm in width and 3 hips [3.5%] 2 mm in width) and 100% of them were not progressive with respect to the last follow-up radiograph. All of the stems had excellent fixation by demonstrating bone ingrowth at the latest follow-up. At the last follow-up, heterotopic ossification was noted in 5 hips. The mean preoperative limb length discrepancy was 9.3 mm and the mean postoperative discrepancy was 3.8 mm. The mean acetabular component angle of the 85 components was 41.2° with a mean anteversion of 22.1°. At the last follow-up, there were no revisions of the femoral component. One patient, 25 months after the index operation, required an acetabular component revision because of recurrent hip dislocation. There were no radiological signs of loosening in any of the short-stem prostheses at the last examination. CONCLUSIONS: The short, metaphyseal-fitting anatomic cementless femoral stem provided stable fixation without relying on diaphyseal fixation.

Intermediate-Term Results of 142 Single-Design, Rotating-Hinge Implants: Frequent Complications May Not Preclude Salvage of Severely Affected Knees.

Rotating-hinge knee prostheses have low survivorship and high complications except in primary arthroplasties in elderly patients. We retrospectively reviewed 142 single third-generation design, rotating hinge prostheses (11 primary procedures and 131 revisions) at 57 months follow up. Implant survival was 73%. Successful two-stage reimplantation for prosthetic infection was 78.4% but new infection rate was 22%. The tibial component was durable while the femoral component was problematic. We observed only one patellar maltracking and no polyethylene wear. A third generation rotating-hinge arthroplasty reconstruction was reliable in complex problems. Outcomes in primary situations were excellent. Complications were the rule rather than the exception in revisions. With timely intervention, attention to soft tissue coverage, and realistic expectations, complications were contained and functional benefits were appreciable.

Low-dose irradiation and constrained revision for severe, idiopathic, arthrofibrosis following total knee arthroplasty.

Treatment options for arthrofibrosis following total knee arthroplasty include manipulation under anesthesia, open or arthroscopic arthrolysis, and revision surgery to correct identifiable problems. We propose preoperative low-dose irradiation and Constrained Condylar or Rotating-hinge revision for severe, idiopathic arthrofibrosis. Irradiation may decrease fibro-osseous proliferation while constrained implants allow femoral shortening and release of contracted collateral ligaments. Fourteen patients underwent fifteen procedures for a mean overall motion of 46° and flexion contracture of 30°. One patient had worsening range of motion while thirteen patients had 57° mean gain in range of motion (range 5°-90°). Flexion contractures decreased by a mean of 28°. There were no significant complications at a mean follow up of 34 months (range 24 to 74 months).

Intramedullary rod and cement static spacer construct in chronically infected total knee arthroplasty.

Two-stage reimplantation, with interval antibiotic-impregnated cement spacer, is the preferred treatment of prosthetic knee joint infections. In medically compromised hosts with prior failed surgeries, the outcomes are poor. Articulating spacers in such patients render the knee unstable; static spacers have risks of dislocation and extensor mechanism injury. We examined 58 infected total knee arthroplasties with extensive bone and soft tissue loss, treated with resection arthroplasty and intramedullary tibiofemoral rod and antibiotic-laden cement spacer. Thirty-seven patients underwent delayed reimplantation. Most patients (83.8%) were free from recurrent infection at mean follow-up of 29.4 months. Reinfection occurred in 16.2%, which required debridement. Twenty-one patients with poor operative risks remained with the spacer for 11.4 months. All patients, during spacer phase, had brace-free ambulation with simulated tibiofemoral fusion, without bone loss or loss of limb length.

A 17-year follow-up of modified "Harrington" reconstruction after acetabular resection.

Acetabular reconstruction after resection of advanced periacetabular metastatic lesion is a complex undertaking. Harrington (J Bone Joint Surg [Am]. 1981;63-653) described a reconstructive technique in class III- and IV-type resections using threaded Steinmann pins and acrylic cement. This technique, although effective for pain relief and restoration of function, is traditionally considered when patient's life expectancy is short because of its questionable durability. A 17-year follow-up of our patient with plasma cell cytoma of the ilium and acetabulum, treated with a modification of the above technique after intralesional curettage, showed no mechanical failure or loosening. This suggests that the construct can be durable where there is no recurrence of disease and can also be a valuable asset in selected nontumor cases in adjunct to contemporary techniques.

Neuroma of the infrapatellar branch of the saphenous nerve a cause of reversible knee stiffness after total knee arthroplasty.

Injury of the infrapatellar branch of the saphenous nerve (ISN) may be caused by a surgical laceration or trauma about the knee and can result in formation of a painful neuroma. There has been no report of knee stiffness after a total knee arthroplasty secondary to a painful neuroma of the ISN. In this report, we present a patient with pain and severe stiffness of her knee after a total knee arthroplasty. A neuroma of the ISN was resected, and the pain as well as the stiffness of the knee resolved. A source of pain such as a neuroma should be considered as a cause of reversible knee stiffness or "pseudoarthrofibrosis" after a total knee arthroplasty.

Immediate weight bearing after cementless total hip arthroplasty.

This study analyzed 399 Balance femoral stems to determine whether immediate full weight bearing following total hip arthroplasty affected radiographic osseointegration. Postoperatively, all patients were permitted unlimited weight bearing. Findings demonstrated osseointegration was successful in 99.5% of femoral components. Of these, 0.5% subsided in the first 6 postoperative weeks and then osseointegrated; 0.5% failed to osseointegrate. Patients with Dorr C bone had a significantly increased rate of subsidence (P=.006). These findings indicate the Balance stem reliably osseointegrates without subsidence in patients with Dorr A or B bone, despite immediate full weight bearing.

Femoral artery and vein injury after cerclage wiring of the femur: a case report.

Iatrogenic injuries to the vascular system are a rare but serious complication of primary and revision hip arthroplasty. These injuries usually occur during screw or retractor placement at the acetabulum or proximal femur. Although vascular injury during the passage of cerclage wires is a fear of all surgeons, its occurrence is yet to be described. This case report describes an unusual injury to the femoral artery and vein by a cerclage wire passed around the femoral midshaft during revision total-hip arthroplasty. It underscores the need for diligent comparison of preoperative and postoperative vascular examinations and emergent vascular surgery consultation when needed to avoid disastrous complications.

Medial gastrocnemius flap for reconstruction of knee extensor mechanism disruption after total knee replacement (TKR).

This chapter describes a technique for reconstruction of the knee extensor mechanism disruption after total knee replacement (TKR). Disruption of the knee extensor mechanism is an infrequent but serious complication. The options for treatment include observation, bracing, fixation with sutures or staples, autologous-tissue augmentation with use of the semitendinosus or gracilis tendon, turndown of the quadriceps tendon and reconstruction with an intercalary allograft. These options have been associated with a high risk of complications and have not addressed the associated problems of contracted devascularized skin flaps or deficient patellar bone stock. The medial gastrocnemius flap has been shown to be suitable for providing soft-tissue coverage of the proximal aspect of the tibia, knee, and distal aspect of the femur. Historically the technique for reconstruction of the extensor mechanism was described for limb salvage after resection of proximal aspect of the tibia for malignant tumors. This described technique is an adaptation of such previously accepted techniques for disruption of the extensor mechanism after total knee arthroplasty (TKA). The use of a medial or an extended medial gastrocnemius flap appears to be a reliable option for reconstruction of a ruptured extensor mechanism after TKA.

Hip-vagina fistula after acetabular revision.

A case of a fistula between the hip and the vagina in a 46-year-old woman after acetabular revision for a failed total hip arthroplasty (THA) is presented. This patient had undergone multiple revision procedures complicated by infection after a primary THA failed because of chronic recurrent dislocation. The patient 18 months after reconstruction of a pelvic discontinuity using an antiprotrusio cage. The chief complaint was weight-bearing groin pain and persistent atypical vaginal discharge. Plain radiographs showed a fracture of the antiprotrusio cage with medial and superior migration of the acetabular cage into the pelvis. An arthrogram showed a fistula between the hip joint and the vagina. To our knowledge, a hip-vaginal fistula has not been reported previously as a complication of THA.

Knee extensor mechanism reconstruction with medial gastrocnemius flap.

Infection after osteotomy of the tibial tubercle can lead to nonunion and chronic osteomyelitis of the tuberosity. Radical debridement for control of infection in this situation may require resection of the sequestrated tuberosity fragment with the resultant problem of disruption of the extensor mechanism of the knee. A review of the literature failed to identify any description of successful treatment of such a complication. The case of a 28-year-old woman with this complication is reported. After resection of the sequestrated tibial tuberosity and sinus tract, the extensor mechanism was reconstructed with the medial gastrocnemius flap in a one-stage procedure. The infection was eradicated successfully and excellent knee function was restored. The technique and 5-year result are presented.