Implant and limb alignment outcomes for conventional and navigated unicompartmental knee arthroplasty.

Accurate implant positioning and restoration of lower limb alignment are major requirements for successful long-term results in unicompartmental knee arthroplasty (UKA). Alignment accuracy was compared between navigated-UKA (nUKA) and conventional-UKA (cUKA) groups using a retrospective matched case-control study (n=129, 58 nUKA, 71 cUKA). Mechanical axis (MA), hip-knee-ankle angle (HKA°), coronal implant alignment, and tibial implant posterior slope were measured. No statistically significant difference was observed when comparing MA, HKA° or coronal implant alignment (p>0.05). Statistical significance was seen with tibial component posterior slope (p=0.04, nUKA 4.2°, cUKA 2.9°); and between intra-operative navigationally determined HKA° and post-operative whole-leg standing (WLS) film HKA°. Navigation does not significantly improve UKA alignment compared to conventional methods. Further studies are needed to justify the use of this technology in UKA.

Knee pain and leg-length discrepancy after retrograde femoral nailing.

We retrospectively studied postoperative knee function and leg-length discrepancy (LLD) in 31 patients with femoral diaphyseal fractures treated with retrograde intramedullary nailing (IMN) between October 1998 and April 2000. Mean follow-up was 25 months, mean knee range of motion was 126 degrees, mean Hospital for Special Surgery knee scores were 89.2 (pain) and 78.3 (function), and mean LLD was 1.19 cm. Despite the theoretically higher knee pain and LLD rates associated with retrograde IMN, we believe it may offer a viable treatment option when the antegrade nailing technique is restricted.

Sexual activity, pregnancy, and childbirth after periacetabular osteotomy.

The purpose of the current study was to determine the effect periacetabular osteotomy has on sexual activity, pregnancy, and childbirth. Eighty-eight female patients who had periacetabular osteotomy were asked to complete a questionnaire concerning the presence of hip pain and changes in the frequency, positions, and satisfaction of sexual activity after periacetabular osteotomy. They also were asked about hip pain during pregnancy and after childbirth, type of delivery, and complications during childbirth. Eighty-four patients (89%) either were very satisfied or satisfied with the surgery. Thirty-eight (40%), 44 (46%), and 24 (25%) patients reported changes in the frequency, positions, and satisfaction of sexual intercourse, respectively. Sixteen women had 24 pregnancies. Fifteen women had vaginal deliveries and eight had Cesarean sections. Less than 5-mm medialization of hip center after correction was associated with pain (in seven of seven patients) and decreased range of motion (in eight of nine patients) during sexual activity. Acetabular retroversion was found in 16 patients postoperatively, and 15 of them had hip pain after periacetabular osteotomy. None of the patients who reported an increased frequency of sexual intercourse had retroversion. The majority will be able to deliver a child vaginally.

Complications in long-term survivors of Ewing sarcoma.

BACKGROUND: Multimodality treatment has dramatically improved the outcome of patients with Ewing sarcoma. However, there appears to be little information concerning treatment-related complications in patients who are long-term survivors. METHODS: Forty-one patients with Ewing sarcoma who were treated between 1960-1980 and who survived the disease by at least 20 years were included in the current study. In a retrospective analysis, all complications related to the multimodality treatment of Ewing sarcoma were assessed. RESULTS: The patient group was comprised of 17 men and 24 women, with a mean age at the time of presentation of 16.8 years (range, 5-51 years). Approximately 20% of the lesions were located in the pelvis. All but 9 patients (78%) received chemotherapy as part of their treatment. The overall follow-up period averaged 25 years (range, 20-36 years). All except 1 patient were alive at the time of final follow-up, with the latter patient dying of radiation-induced secondary malignancy after 33 years. Only 17 patients (41%) were found to be free of any complication. These included metastases, local recurrence, secondary malignancies, pathologic fractures, and radiation-associated and chemotherapy-associated morbidities. CONCLUSIONS: Although the patients in the current study were treated successfully in terms of surviving an aggressive tumor, the high complication rate in this group of long-term survivors is noteworthy and indicates that long-term follow-up should be mandatory.

Pathologic fracture as a complication in the treatment of Ewing's sarcoma.

The purpose of the current study was to define the outcome of patients with Ewing's sarcoma who sustained a fracture either at initial presentation or subsequent to multimodal treatment, and to identify parameters that may influence the treatment of these patients. The age of the 21 males and 14 females who sustained a fracture during the treatment for Ewing's sarcoma averaged 15 years (range, 4-30 years) at diagnosis. Fourteen patients presented with a pathologic fracture, whereas 21 patients had a fracture develop subsequent to the initial treatment at a mean of 4 years (range, 1-19 years). The femur was the most common location (50%). At a mean followup of 10 years (range, 1-33 years), 21 of 35 patients (60%) were alive and free of disease. There was no local recurrence, but there was one postradiation sarcoma associated with the fracture. Comparing the followup of patients who sustained the fracture at presentation with the followup of patients who subsequently had a fracture, no statistically significant difference was found (117 months versus 124 months). Overall, pathologic fracture in association with Ewing's sarcoma does not seem to be a negative prognostic parameter with respect to survival in this series. Therefore, a fracture at presentation may not mandate amputation. However, it occurs frequently subsequent to initial multimodal treatment because of delayed fracture healing. Because conservative or minimal osteosynthesis have high failure rates, more aggressive resection and reconstruction have to be considered carefully.

Ewing's sarcoma and the development of secondary malignancies.

The multimodality treatment approach for patients with Ewing's sarcoma during the last decades has dramatically improved patient long-term survival. With improved survival, late consequences and morbidity associated with treatment have become apparent. Among the morbidity associated with treatment is the increased risk of development of secondary malignancies. Therefore, the purpose of the current study was to define the outcome of patients who had secondary malignancy develop subsequent to the diagnosis and treatment of Ewing's sarcoma. Of the 397 patients treated for Ewing's sarcoma at our institution during the past 25 years, 26 patients (6.5%) had 29 secondary malignancies develop. The mean age of the 13 males and 13 females averaged 16 years (range, 6-51 years), and the interval from the diagnosis of the Ewing's sarcoma to the development of the secondary malignancy averaged 9.5 years (range, 1-32.5 years). The secondary malignancies included eight hematopoietic cancers, 12 sarcomas, and nine carcinomas. Although carcinomas most likely represent the general risk of developing cancer in the healthy population, the sarcomas were caused by radiation therapy and the hematopoietic tumors caused by chemotherapy. The latter occurred at a mean latent period of 4.8 years (range, 1.7-12.9 years), and the sarcomas occurred after a mean of 10.9 years (range, 1.5-32.5 years). At the mean followup of 15 years (range, 2-33 years) from diagnosis of Ewing's sarcoma and at a mean followup of 5 years (range, 0.5-28 years) from diagnosis of the second malignancy, 14 patients are alive (43%); however, patients with either sarcomas or hematopoietic secondary malignancies had not only a significantly shorter interval from secondary malignancy to followup (3.3 and 1.2 years, respectively, versus 7.3 years), but also a more dismal prognosis (eight of 12 or six of eight patients died, respectively, versus one of nine). Although the risk of having secondary malignancy develop after the treatment of a Ewing's sarcoma may be only slightly greater than the risk compared with other childhood cancers, patients with hematopoietic and radiation-induced secondary malignancies have a detrimental prognosis. Patients with Ewing's sarcoma need to be followed up carefully and frequently.

Detection of chimerism following vascularized bone allotransplantation by polymerase chain reaction using a Y-chromosome specific primer.

Chimerism following allogeneic organ transplantation is a phenomenon known to occur and be associated with development of immunologic tolerance in allotransplantation. However, little is known about graft cell migration following vascularized bone allografting. In this study, chimerism was assessed following vascularized tibia transplantation from male DA or PVG donors to female PVG rat recipients using a semi-quantitative polymerase chain reaction for the Y-chromosome. FK-506 (Tacrolimus) was administered after transplantation for immunosuppression. All immunosuppresssed PVG rat recipients of PVG bone grafts showed a high level of chimerism (1%) in the thymus, spleen, liver and cervical lymph nodes at 18 weeks post-transplant. Donor cells were also detected in the contralateral tibia and humerus. In non-immunosuppressed PVG rat recipients of DA bone grafts, donor cells were detected in the spleen in three of five rats within 2 weeks post-transplant. In these animals the bone grafts were severely rejected. In immunosuppressed PVG rat recipients of DA bone grafts, two of five, four of eight and eight of 10 rats showed low level chimerism (0.1%) in peripheral blood at 1, 12, and 18 weeks post-transplant. Six rats showed a high level of chimerism in the spleen and thymus. Histological studies revealed no rejection findings through 18 weeks post-transplant. Our results indicate that chimerism, or the presence of graft cells in host tissue, may occur in the face of acute rejection and be demonstrable following vascularized isograft and allograft living bone transplantation when chronic immunosuppression is maintained. Graft vascular patency during the short-term likely allows cellular migration, even in the face of acute rejection. Long-term survival and proliferation of graft marrow elements in host tissue may be possible with adequate immunosuppression.

Fate of donor cells in vascularized bone grafts: identification of systemic chimerism by the polymerase chain reaction.

Systemic chimerism, or the movement of cells from a transplanted tissue into host organs, is a phenomenon known to occur in association with development of immunological tolerance in allotransplantation. However, little is known about the fate and movement of cells into or out of autogenous free tissue transfers, including vascularized bone grafts. The purpose of this study was to identify systemic chimerism in vascularized bone grafts by transplantation of a vascularized tibiofibular graft from isogenous (inbred) male Lewis rats to female recipients. Donor (male) cells could be identified in the recipient (female) tissues by semiquantitative polymerase chain reaction analysis for a Y chromosome-specific DNA sequence. Chimerism was assessed at 1, 12, 18, and 24 weeks after transplantation. Competitive polymerase chain reaction study using the specific primers for a Y-chromosome marker ( gene) and an autosomal gene (GAPDH) allowed detection of small amounts of male cells in a large pool of female cells and measurement of their relative proportions as a function of time. Of 19 nonimmunosuppressed recipients, nine animals (47 percent) showed low-level chimerism (<0.1 percent) in the peripheral blood. Nine (47 percent), three (16 percent), and two (11 percent) recipients showed high-level chimerism (>1 percent) in the spleen, liver, and thymus, respectively, at final assessment. Donor cells were detected in all bone grafts and in six contralateral tibial bones (i.e., 67 percent of sampled contralateral tibial bones) at 18 and 24 weeks after transplantation. Twenty-four recipients were immunosuppressed with FK506 (tacrolimus) to suppress reaction to a minor histocompatibility barrier present on the Y chromosome. In this group, 14 animals (58 percent) showed low-level chimerism in peripheral blood and 12 (50 percent), eight (33 percent), and one (4 percent) recipients showed high-level chimerism in the spleen, thymus, and liver, respectively. Transplanted cells were detected in nine contralateral tibial bones (i.e., 60 percent of sampled contralateral tibial bones) at 12 and 18 weeks after surgery. The results indicate that polymerase chain reaction for the Y chromosome is a useful tool for differentiating between donor and recipient cell populations experimentally using sex-mismatched tissues in a rat model. This study demonstrated that systemic chimerism occurs after successful vascularized bone transplantation. Transplanted cells not only survive in the graft but also gradually migrate into the recipient's body.