Unicondylar osteoarticular allografts of the knee

BACKGROUND

In the management of a resected distal femoral or proximal tibial condyle as the result of tumor or trauma, a unicondylar osteoarticular allograft is currently the only reconstructive option that avoids the sacrifice of the unaffected condyle. The purposes of this study were to perform a survival analysis of unicondylar osteoarticular allografts of the knee and to evaluate the complications.

METHODS

We retrospectively reviewed the results of forty large unicondylar osteoarticular allograft procedures in thirty-eight patients who were followed for a mean of eleven years. Twenty-nine allografts were femoral transplants and included eleven medial and eighteen lateral femoral condyles. Eleven allografts were tibial transplants, including four medial and seven lateral tibial condyles. The procedure was performed after a tumor resection in thirty-six patients and to replace condylar loss after a severe open fracture in the remaining two patients. Complications were analyzed, and allograft survival from the date of implantation to the date of revision or the time of the latest follow-up was determined. Functional and radiographic results were documented according to the Musculoskeletal Tumor Society scoring system at the time of the latest follow-up.

RESULTS

One patient died of tumor-related causes without allograft failure before the two-year follow-up evaluation. The global rate of allograft survival at both five and ten years was 85%, with a mean follow-up of 148 months. In six patients, the allografts were removed at an average of twenty-six months (range, six to forty-eight months) and these were considered failures. All six patients underwent a second allograft procedure including two new unicondylar and four bicondylar reconstructions. The mean radiographic score for the thirty-three surviving allografts evaluated was 89%, with an average functional score of 27 of a possible 30 points.

CONCLUSIONS

Unicondylar osteoarticular allografts of the knee appear to be a reliable alternative for patients in whom reconstruction of massive osteoarticular bone loss is limited to one condyle of the femur or the tibia.

Osteochondral transplantation to treat osteochondral lesions in the elbow

BACKGROUND

Effective treatment of osteochondral lesions in the elbow remains challenging. Arthroscopic débridement and microfracture or retrograde drilling techniques are often insufficient and provide only temporary symptomatic relief. The purpose of this study was to evaluate the treatment of these lesions with osteochondral autografts.

METHODS

From 1999 to 2002, seven patients with osteochondral lesions of the capitellum humeri (five patients), trochlea (one patient), or radial head (one patient) were treated with cylindrical osteochondral grafts, which were harvested from the non-weight-bearing area of the proximal aspect of the lateral femoral condyle. The patients (three female and four male patients with an average age of seventeen years) were evaluated preoperatively and postoperatively, with an average follow-up of fifty-nine months. The Broberg and Morrey score was chosen for functional evaluation of the elbow (with regard to motion, pain, strength, activities of daily living, and stability), and the American Shoulder and Elbow Surgeons score was used for the analysis of pain. All patients had imaging studies done preoperatively to evaluate the defect and postoperatively to assess the ingrowth and viability of the graft. The ipsilateral knee was examined for donor-site morbidity.

RESULTS

The Broberg and Morrey score improved from a mean (and standard deviation) of 76.3 +/- 13.2 preoperatively to 97.6 +/- 2.7 postoperatively, and pain scores were significantly reduced (p < 0.05). The mean elbow extension lag of 4.7 degrees +/- 5.8 degrees was reduced to 0 degrees postoperatively. Compared with the contralateral side, there was a mean preoperative flexion lag of 12.9 degrees +/- 13.8 degrees . At the time of the final follow-up, flexion was free and was equal bilaterally in all patients. None of the plain radiographs made at the time of follow-up showed any degenerative changes or signs of osteoarthritis. The postoperative magnetic resonance imaging scans showed graft viability and a congruent chondral surface in all seven patients. No donor-site morbidity was noted at one year postoperatively.

CONCLUSIONS

The osteochondral autograft procedure described in the present study provides the opportunity to retain viable hyaline cartilage for the repair of osteochondral lesions in the elbow while restoring joint congruity and function and perhaps reducing the risk of osteoarthritis. These medium-term results suggest that the risks of a two-joint procedure are modest and justifiable. In addition, the described technique provides an option for revision surgery after the failure of other surgical procedures.

Intercalary femoral reconstruction with extracorporeal irradiated autogenous bone graft in limb-salvage surgery

Between 1996 and 2003, 16 patients (nine female, seven male) were treated for a primary bone sarcoma of the femur by wide local excision of the tumour, extracorporeal irradiation and re-implantation. An additional vascularised fibular graft was used in 13 patients (81%). All patients were free from disease when reviewed at a minimum of two years postoperatively (mean 49.7 months (24 to 96). There were no cases of infection. Primary union was achieved after a median of nine months (interquartile range 7 to 11). Five host-donor junctions (16%) united only after a second procedure. Primary union recurred faster at metaphyseal junctions (94% (15) at a median of 7.5 months (interquartile range 4 to 12)) than at diaphyseal junctions (75% (12) at a median of 11.1 months (interquartile range 5 to 18)). Post-operatively, the median Musculoskeletal Tumour Society score was 85% (interquartile range 75 to 96) and the median Toronto Extremity Salvage score 94% (interquartile range 82 to 99). The Mankin score gave a good or excellent result in 14 patients (88%). The range of movement of the knee was significantly worse when the extracorporeally irradiated autografts were fixed by plates rather than by nails (p = 0.035). A total of 16 (62%) of the junctions of the vascularised fibular grafts underwent hypertrophy, indicating union and loading. Extracorporeal irradiation autografting with supplementary vascularised fibular grafting is a promising biological alternative for intercalary reconstruction after wide resection of malignant bone tumours of the femur.

Intramedullary step-cut osteotomy for revision total hip arthroplasty with allograft-host bone size mismatch

Eleven revision total hip arthroplasties were treated with proximal segmental femoral allograft reconstruction in which the diameter of the distal host bone was larger than the largest long-stem femoral component which could fit into the segmental allograft. A long, lateral step-cut osteotomy of the allograft was used with placement of the lateral cortical allograft inside the distal host bone. All allograft-host bone junctions healed. The average time to union was 6.7 months. The long step-cut osteotomy provides stability of the allograft-host bone junction when the diameter of the host bone is larger than the allograft. The osteotomy also provides a large surface area of contact between the allograft and host bone.

Segmental bony defect of the proximal phalanx in the great toe reconstructed by free vascularized bone graft from the supracondylar region of the femur: a case report

We report the case of a 24-year-old man with a segmental bone defect of the proximal phalanx of the great toe that was successfully reconstructed by free vascularized bone graft (FVBG) from the supracondylar region of the femur after initial stabilization with external fixation and temporary antibiotic-impregnated bone cement. His functional outcome at 22 months follow-up was excellent. On the basis of this experience, FVBG from the supracondylar region of the femur can be used as an option for treating segmental bone defects of the great toe.

Transplantation of the hand, face, and composite structures: evolution and current status

This article reviews the world experience in the newly emerging field of composite tissue allotransplantation. These allografts contain multiple tissues that are usually musculoskeletal structures with a skin or epithelial surface, such as hand, facial structures, larynx, tongue, ear, knee/femur, abdominal wall, and penis. They represent a new transplantation field, with only a 10-year experience and just over 50 clinical cases. This review of the 10-year world experience found uniform technical success, immunologic biology, and immunosuppression regimens very similar to solid organ transplants, and success strongly correlated with adherence to guidelines for psychiatric screening, thorough preparation of patient and families, intense postoperative monitoring, and assurance of medication access. All failures reported have been caused by lapses in these parameters. This early experience shows a great potential for application of these new procedures to the most challenging reconstructive needs.

Bone Dowels in Anterior Lumbar Interbody Fusion

Since the Food and Drug Administration approved the Babgy-Kuslich BAK cage for anterior lumbar interbody fusion (ALIF), various threaded interbody fusion devices have been introduced. Bone dowels offer several theoretical advantages over cages with regard to stress shielding; the purpose of this study was to assess the efficacy of bone dowels in interbody fusion. All patients undergoing ALIF performed by the senior author between 1998 and 2001 were retrospectively reviewed. Patients' preoperative and postoperative neurologic status, functional status, and both back and radicular pain were assessed according to a previously published outcome measure. Between 1998 and 2000, 23 patients underwent ALIF with cortical femoral allograft bone dowels. One patient underwent simultaneous bone dowel and titanium cage placements and was therefore excluded from further analysis. The 22 remaining patients underwent a total of 33 fused segments; of these, 21 patients were available for follow-up. Mean clinical follow-up was 30.6 months. Mean imaging follow-up was 21 months. There were 5 instances of radiographic nonunion (3 symptomatic and 2 asymptomatic). The incidence of technical failures and complications related to the bone dowels was 17%. Bone dowels failed and caused symptoms only in patients with a stand-alone ALIF. There were no clinical failures in patients treated with supplemental anterior or posterior spinal fixation. These data demonstrate that marginal fusion rates and functional success rates can be achieved using stand-alone bone dowels for ALIF. The clinical success and fusion rates are significantly higher if ALIF dowels are shielded from stress with rigid spinal instrumentation.

Severe tacrolimus toxicity in rabbits

OBJECTIVES

Tacrolimus is an effective immunosuppressant, safely administered in clinical practice by monitoring blood levels. In experimental transplants, many dosage regimens have been reported, often without such determinations. Anorexia and organ toxicity commonly occur. We report the toxic effects of tacrolimus in rabbits receiving intramuscular injections (1 mg/kg/d) and the subsequent dosage modifications that resulted in improved animal survival without toxic effects.

MATERIALS AND METHODS

To obtain nontoxic drug concentrations in the blood, 3 dosage regimens were required. Drug concentrations were targeted using therapeutic human values as a guide (range, 5-20 ng/mL). First, a group of 12 Dutch-Belted rabbits received vascularized femoral allografts and were treated with intramuscular dosages of tacrolimus (1 mg/kg/d) for 14 days. Subsequently, dosage reductions in 10 more rabbits, to 0.2 mg/kg/d for 14 days, were necessary. Finally, another group of 20 rabbits was treated with 0.08 mg/kg for 3 days, and then every other day thereafter. Weight loss > 30%, cardiopulmonary failure, and/or creatinine levels > 221 micromol/L were the criteria approved by our local Institutional Animal Care and Use Committee for euthanizing the animals. Treated animals were compared with 20 nonimmunosuppressed controls that underwent the same operation.

RESULTS

At an intramuscular dosage of 1 mg/kg/d, the mean tacrolimus blood level was 90.7 ng/mL. Ten of the 12 animals in the original group died or required euthanasia. At necropsy, renal failure, cardiac abnormalities, and pulmonary edema were found. The tacrolimus dosage of 0.2 mg/kg/d produced a mean tacrolimus blood level of 17.6 ng/mL; however, 8 of the subsequent 10 rabbits died when given this dosage. Ultimately, the 0.08 mg/kg regimen in 20 rabbits permitted survival of 18 animals with a mean tacrolimus blood level of 6.8 ng/mL. None of 20 nonimmunosuppressed controls died after surgery.

CONCLUSIONS

For successful immunosuppression, Dutch-Belted rabbits require intramuscular tacrolimus dosages lower those required in other rabbit breeds. This has not been reported previously. The 0.08 mg/kg/d dosage combined with intermittent drug level monitoring permits survival without significant complications.

Fresh osteochondral allografting in the treatment of osteochondritis dissecans of the femoral condyle

BACKGROUND

The treatment of osteochondritis dissecans in the adult knee can be challenging. As part of our comprehensive treatment program, fresh osteochondral allografts have been used in the surgical management of osteochondritis dissecans of the femoral condyle.

HYPOTHESIS

Fresh osteochondral allograft transplantation will provide a successful surgical treatment for osteochondritis dissecans of the femoral condyle.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Sixty-six knees in 64 patients underwent fresh osteochondral allografting for the treatment of osteochondritis dissecans. Each patient was evaluated both preoperatively and postoperatively using an 18-point modified D'Aubigné and Postel scale. Subjective assessment was performed using a patient questionnaire. Radiographs were evaluated preoperatively and postoperatively.

RESULTS

Mean follow-up was 7.7 years (range, 2-22 years). There were 45 men and 19 women with a mean age of 28.6 years (range, 15-54 years). All patients had undergone previous surgery. Forty-one lesions involved the medial femoral condyle, and 25 involved the lateral femoral condyle. All were osteochondritis dissecans type 3 or 4. The mean allograft size was 7.5 cm(2). One knee was lost to follow-up. Of the remaining 65 knees, 47 (72%) were rated good/excellent, 7 (11%) were rated fair, and 1 (2%) was rated poor. Ten patients (15%) underwent reoperation. The mean clinical score improved from 13.0 preoperatively to 16.4 postoperatively (P < .01). Fifty-nine of 64 patients completed questionnaires. Subjective knee function improved from a mean of 3.4 to 8.4 on a 10-point scale (P < .01).

CONCLUSION

With greater than 70% good or excellent results, fresh osteochondral allograft transplantation is a successful surgical treatment for osteochondritis dissecans of the femoral condyle.

Vascularised corticoperiosteal grafts from the medial femoral condyle for difficult non-unions of the upper limb

The vascularised corticoperiosteal graft was introduced by Sakai and Doi, in 1991, as a means to achieve bony union under unfavourable conditions. We present our experience with this vascularised graft, taken from the femoral condyle, in six patients with difficult non-unions (5) or other bony problems (1) in the upper limb. In five cases, a long bone defect--two humeral, two ulnar and one radial--was involved. All had had between three and seven previous operations. Two of the non-unions were secondary to infection. The others had had conventional grafting on two or three previous occasions each. In the sixth case, a corticoperiosteal graft was used to promote healing in a combined carpometacarpal and intercarpal dislocation with a very poor bed. All of the grafts survived without complications and all of the bones healed radiologically in less than three months. Three patients achieved a normal range of motion and two obtained a functional range of motion with only slight limitations. The carpometacarpal arthrodesis was healed soundly at five weeks.

Cartilage thickness matching of selected donor and recipient sites for osteochondral autografting of the medial femoral condyle

Osteochondral transplantation requires a careful assessment of the location of donor plugs. A mismatch of cartilage thickness between the donor and recipient site may lead to abnormal stresses and poor function. The objective of this study was to characterize the recommended donor and recipient sites with respect to cartilage thickness in younger individuals. Nineteen arthro CT (13 men, 6 women), which had been carried out in a population of less than 50 years old were studied. Recommended donor sites have included the posterior femoral condyles, the medial and lateral aspect of the trochlea and central, medial and lateral sides of the intercondylar notch. Recipient sites were studied at four regions of interest on the medial femoral condyle usually involved in osteochondritis dissecans. Average cartilage thickness was calculated on the digital version of the reference cuts for each site and compared. The sensitivity of the precision of the measurements to observer variability was evaluated using intra- and inter-observer correlation coefficient tests. The femoral cartilage in the knee was thickest in the recipient sites (2.49 mm, SD 0.64) than in donor sites (1.79 mm, SD 0.43) (P<0.0001). There was no differences between the different donor sites, unless for the antero lateral intercondylar notch which was significantly thinner (1.3 mm, SD 0.29) than the other sites (P<0.05). The cartilage of the donor site was consistently thinner than the cartilage of the recipient sites. Between the different donor sites, the lateral side of the intercondylar notch was significantly thinner than the other donor sites and should not be harvested in priority.

Treatment of persistent non-union of the humerus using a vascularized bone graft from the supracondylar region of the femur

Six patients with recalcitrant post-traumatic humeral shaft non-unions were treated using vascularized bone grafts from the supracondylar region of the femur. The initial state of injury showed that four fractures were closed, while two were open fractures. At the acute stage, five fractures were fixed using intramedullary nailing, while one was fixed with a plate. In all patients, a bony flap was placed on the cortex after decortication. The size of the harvested bone flap ranged between 4 x 2.5 cm and 5 x 3 cm. After fixation of the bony flap, the inferior genicular artery and vein were anastomosed to the deep brachial artery and vein. The mean time required to obtain radiographic bone union was 3.3 months. The only graft-site complication involved transient mild paresthesia in the saphenous nerve area in one patient. This procedure was useful for atrophic nonunions without substantial bone defects of the humeral shaft.

Proximal femoral allograft treatment of Vancouver type-B3 periprosthetic femoral fractures after total hip arthroplasty. Surgical technique

BACKGROUND

Periprosthetic femoral fractures following total hip arthroplasty are becoming more prevalent. When a fracture occurs in a femur with substantial proximal bone deficiency, the surgical options for revision are limited. One option includes the use of a proximal femoral allograft.

METHODS

We retrospectively assessed the results and complications of the use of a proximal femoral allograft to treat twenty-five Vancouver type-B3 periprosthetic fractures in twenty-four patients. The mean duration of follow-up was 5.1 years. Clinical results were graded with use of the Harris hip score. Radiographs were assessed for evidence of trochanteric union, host-allograft union, allograft resorption, and component loosening or fracture. Failure of the procedure was defined as the need for revision surgery requiring graft removal.

RESULTS

The mean postoperative Harris hip score was 70.8. At the time of the final follow-up, twenty-one of the twenty-four patients reported no or mild pain and twenty-three patients were able to walk; fifteen required a walking aid. The greater trochanter united in seventeen of the twenty-five hips (68%), and osseous union of the allograft to the host femur occurred in twenty hips (80%). There was mild graft resorption in four hips and moderate graft resorption in two. Four (16%) of the twenty-five hips required repeat revision.

CONCLUSIONS

The use of a proximal femoral allograft for the treatment of a Vancouver type-B3 periprosthetic femoral fracture can provide a satisfactory result in terms of pain relief and function at five years.

Comparison of polyetheretherketone cages with femoral cortical bone allograft as a single-piece interbody spacer in transforaminal lumbar interbody fusion

OBJECT

Transforaminal lumbar interbody fusion (TLIF) is an accepted alternative to circumferential fusion of the lumbar spine in the treatment of degenerative disc disease, spondylolisthesis, and recurrent disc herniation. To maintain disc height while arthrodesis takes place, the technique requires the use of an interbody spacer. Although titanium cages are used in this capacity, the two most common spacers are polyetheretherketone (PEEK) cages and femoral cortical allografts (FCAs). The authors compared the clinical and radiographic outcomes of patients who underwent TLIF with pedicle screw fixation, in whom either a PEEK cage or an FCA was placed as an interbody spacer.

METHODS

The charts and x-ray films obtained in 39 patients (age range 33-68 years, mean 44.7 years) who underwent single-level TLIF between October 2001 and April 2004 and in whom either a PEEK cage (18 patients) or FCA (21 patients) was placed as an interbody spacer were evaluated in a retrospective study. Radiological outcome was based on fusion rate and a comparison of the initial postoperative lordotic angle on standing lateral radiographs with that at long-term follow up (mean follow up 15.1 months, minimum 12 months). To control for variations in radiographic magnification, the authors used lordotic angle as an indirect measure of disc space height. Clinical outcome was assessed using the Oswestry Disability Index (ODI). There were no major complications in either group. Radiographically documented fusion occurred in all patients in the PEEK group and 95.2% of those in the FCA group. Pseudarthrosis developed in one patient in the FCA group, and this patient underwent additional surgery. In both groups, the mean lordotic angle changed by less than 2.20 degrees during the postoperative period, and the mean postoperative ODI score was more than 40 points lower than the mean preoperative score. There was no significant difference between the two groups in mean change in lordotic angle (p = 0.415) and mean change in ODI score (p = 0.491).

CONCLUSIONS

Both PEEK cages and FCAs are highly effective in promoting interbody fusion, maintaining postoperative disc space height, and achieving desirable clinical outcomes in patients who undergo TLIF with pedicle screw fixation. The advantages of PEEK cages include a lower incidence of subsidence and their radiolucency, which permits easier visualization of bone growth.

The superficial inferior epigastric artery fascia flap in the rabbit

In reconstructive surgery, fascial flaps provide thin, pliable tissue for mucosal closure or serve as a highly vascularized support for skin grafts. Their angiogenic potential is used for experimental neovascularization of avascular tissue grafts. However, most fascial flaps in animal surgery have random pattern design with short reach. As a pilot study for a femur revascularization project in rabbits, a new axial fascial flap is described based on the superficial inferior epigastric (SIE) vessels. They were used in this species previously only as ligated bundles or in fasciocutaneous flaps. The topographical anatomy of the SIE-vessels, lower abdominal fascia, and panniculus carnosus are outlined. The angiogenic capabilities are demonstrated microangiographically by abundant vessel formation in a femur allograft. Used in a pedicled fashion, this flap is an alternative to femoral and saphenous vessels for prefabrication or revascularization procedures in the lower abdomen, genital area, and thigh. Distant recipient sites seem possible with microsurgical transfer.

Allopeptide-pulsed dendritic cells and composite tissue allograft survival

Composite tissue allografts (CTAs) contain their own reservoir of vascularized bone marrow, offering novel aspects for the induction of donor-specific tolerance. Additionally, the manipulation of recipient dendritic cells, pulsed with donor allopeptide, has been shown to engender solid organ allograft survival. To exploit these modalities, we have developed a protocol utilizing injection of recipient bone marrow-derived dendritic cells (BMDCs) pulsed with a donor-derived peptide for use in CTA transplantation. Six days prior to orthotopic hind-limb transplantation, Lewis rats received IV injection of donor allopeptide-pulsed, recipient BMDCs, in conjunction with a single dose of anti-lymphocyte serum. Control groups displayed signs of allograft rejection within 5 days postoperatively. Animals within the primary experimental cohort demonstrated prolongation of graft survival to an average of 8 days, and exhibited low numbers of donor T cells. The use of BMDCs in conjunction with transient immunosuppression has potential therapeutic application for induction of donor-antigen-specific tolerance to hind limb allografts.

Chimerism induction in vascularized bone marrow transplants augmented with bone marrow cells

Composite tissue allografts (CTAs) are currently accepted in the clinic; however, long-term immunosuppression is still needed for allograft survival. The presence of donor-specific chimerism may induce tolerance. Thirty-six vascularized bone marrow transplantation (VBMT) allotransplantation were performed across MHC barrier under short-term protocol of 7-day alphabeta-TCRmAb and Cyclosporin A therapy to determine the efficacy of VBMT alone and VBMT augmented with donor bone marrow transplantation (BMT) in chimerism induction. Flow cytometry analysis revealed that VBMT supported with donor BMT directly into the bone resulted in chimerism augmentation and maintenance compared to VBMT. In vivo and in vitro tolerance testing showed prolonged survival of donor skin graft up to 35 days and moderate reactivity in MLR assay that suggests only tolerance induction. Transplantation of vascularized bone without chronic immunosuppression provides a substantial source of bone marrow cells, leading to the development of stable donor-specific chimerism.

The morbidity associated with osteochondral harvest from asymptomatic knees for the treatment of osteochondral lesions of the talus

BACKGROUND

Mosaic autogenous osteochondral transplantation has been used to treat large osteochondral defects.

HYPOTHESIS

There is potential, previously unrecognized donor-site morbidity associated with osteochondral harvest from asymptomatic knees for the treatment of talar osteochondral defect lesions.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Fifteen patients underwent mosaic osteochondral transplantation to treat a talar osteochondral defect lesion, with 11 patients available for follow-up. A Lysholm knee score was used to assess donor-site morbidity at a mean follow-up of 47 months (range, 7-77 months). Mean age was 29 years (range, 21-44 years). A single surgical team performed the mosaicplasties. Significance was determined using the Student t test.

RESULTS

All patients had asymptomatic knees preoperatively. Mean postoperative Lysholm score was 81 (range, 49-100). By Lysholm criteria, 5 rated as excellent, 2 as good, and 4 as poor. No significant difference was detected in terms of the harvest method or the number of grafts obtained from those having an excellent rating versus those having a good/poor rating. Patients rated as good/poor cited knee instability in daily activities as the most common problem. One had knee pain and patellar instability after osteochondral harvest by lateral arthrotomy that required a subsequent lateral retinacular release and tibial tubercle osteotomy.

CONCLUSION

This study demonstrates that donor-site morbidity after osteochondral harvest can be significant. In this population, those who experienced a decline in knee function had problems performing activities of daily living. When performing these procedures, the authors recommend that surgeons consider these risks and discuss them with their patients.

Effect of hydrogen peroxide on osteoinduction by demineralized bone

The osteoinductive capacity of demineralized bone matrix (DBM) has led to wide use of this material for surgical reconstruction. Preparation of DBM often includes sterilization with ethylene oxide, disinfection with various chemical agents, or irradiation. Exposure to hydrogen peroxide (H2O2) is used for both sterilization and bleaching of bone, the latter primarily for cosmetic reasons. We investigated the effect of H2O2, on the osteoinductive capacity of DBM. Cortical bone implants prepared from rat femurs were placed into 3% H2O2 solution. Control specimens were not exposed to H2O2. Bones were then lipid-extracted, demineralized, sterilized with ethylene oxide, and freeze-dried in an identical manner. Allografts were implanted into rat hosts for 1 to 3 weeks. Osteoinduction proceeded rapidly in implants not exposed to H2O2, with chondrocytes and new bone appearing in the implant. After 3 weeks, perforations in the implant were largely replaced with new bone. In contrast, osteoinduction did not occur in implants treated with H2O2. Perforations in H2O2-treated implants were filled with vascularized fibrous tissue, but no cartilage or bone. These findings reveal that H2O2 used for disinfection or bleaching of DBM can abolish its osteoinductive capacity in rats.

[Result of hydrodissection of the paratendon of the patellar tendon during bone-tendon-bone graft reconstruction of the anterior cruciate ligament]

BACKGROUND

We undertook this study to evaluate the clinical and functional effect of hydrodissetion of the paratendon in the postoperative period of patients submitted to surgery of reconstruction of anterior cruciate ligament.

METHODS

A non-controlled clinical study was conducted at the Unidad de Alta Especialidad de Ortopedia y Traumatología "Magdalena de las Salinas," Instituto Mexicano del Seguro Social, Mexico City. Twenty two patients and 23 controls were included. Surgical intervention consisted of a bone-tendon-bone technique with hydrodissection and without hydrodissection of the paratendon.

RESULTS

The following results were obtained: functionality of the knee, pain, extension and flexion. Male: 20 vs. 22; female: 2 vs. 1 (p = 0.581), age: 29 +/- 4.6 years vs. 26 +/- 6.2 (0.946); weight: 68 +/- 8.8 vs. 72 +/- 6.2 (p = 0.190); height: 1.60 m +/- 4.8 vs. 1.62 m +/- 7.5 (p =0.909). Side: right: 5 vs. 5; left: 17 vs. 18 (p = 0.937). Evaluation scale of Knee Index: 84 +/- 4 vs. 70 +/- 8; pain: 10 days: 3.7 +/- 1.6 vs. 6.2 +/- 1.4, 4 weeks: 1.3 +/- 1.6 vs. 4.1 +/- 2.1 (p <0.001) flexion: 95 +/- 6.7 degrees vs. 86 +/- 6.1 degrees (p <0.001) group of hydrodissection vs. no hydrodissection, respectively.

CONCLUSIONS

In the immediate postoperative period (4 weeks), pain is diminished and range of mobility increases as a result of the decrease of pain.

Bone allograft non-union is related to excessive osteoclastic bone resorption: a sheep model study

Using a sheep femoral allograft model we have investigated the cellular and molecular mechanisms associated with non-union of bone allografts. Histomorphometric analysis revealed that allograft non-unions featured both marked increases in osteoclast (OC) numbers and total eroded bone surface as compared to allografts which had undergone direct union. Three distinct cellular layers lying adjacent to the allograft bone surface were identified in all non-union cases. The outer or fibroblastic layer contained an abundance of fibroblasts and connective tissue. Circumscribing this layer was a band of synovial-like cells consisting mainly of large spindle-shaped mononuclear cells mixed with scattered round-shaped mononuclear cells. The third layer, which was directly juxtaposed to the allograft bone surface, consisted predominantly of multinuclear OCs which were positively identified by calcitonin receptor immunohistochemistry. Interestingly, in-situ hybridisation revealed that surrounding synovial-like cells in non-union allografts, expressed abundant gene transcripts for receptor activator NF-kappaB ligand (RANKL), a membrane bound factor critical for both the induction of OC activity and osteoclastogenesis. We propose that excessive bone resorption by host OCs contributes, at least partially, to the failure of bone allografts. The production of RANKL by synovial-like fibroblasts may be the driving force responsible for the elevated generation and activation of OCs. Based on such evidence novel therapeutic strategies for the treatment of non-union bone allografts using anti-bone resorbing agents may be devised.

Self-reported patient outcomes at a minimum of 5 years after allograft anterior cruciate ligament reconstruction with or without medial meniscus transplantation: an age-, sex-, and activity level-matched comparison in patients aged approximately 50 years

PURPOSE

Patient outcomes at a minimum of 5 years after medial meniscus transplantation and primary anterior cruciate ligament (ACL) reconstruction via allograft tissues were compared with those of age-, sex-, and activity level-matched patients who underwent meniscal repair or partial meniscectomy and primary ACL reconstruction via allograft tissues.

METHODS

Eight patients (mean age, 51 +/- 5 years; three women and five men) at 5.5 +/- 0.5 years after medial meniscus transplantation and ACL reconstruction (group 1) and eight matched patients (mean age, 50 +/- 5 years; three women and five men) at 5.1 +/- 0.5 years after meniscal repair or partial meniscectomy and ACL reconstruction (group 2) completed the meniscus allograft clinical registry questionnaire, which combined the modified Lysholm knee scoring scale, the 1999 International Knee Documentation Committee subjective knee evaluation, and the knee pain level score on a 10-cm visual analog scale.

RESULTS

Both groups displayed similar improvements in the modified Lysholm knee scoring scale components of pain, knee stability, squatting, stair climbing, and limping, as well as overall score (P < .05). Only group 2 displayed significant reductions in swelling. The groups displayed similar improvements in the 1999 International Knee Documentation Committee subjective knee evaluation components of sitting, rising from a chair, running, jumping, and stopping quickly, as well as overall score (P < .05). They also displayed significant improvements in the visual analog scale knee pain level score; however, group 1, which displayed greater preoperative pain levels, had considerably larger reductions. Most group 1 patients (7/8 [87.5%]) and all group 2 patients (8/8 [100%]) considered their surgery to be a success and would undergo the same procedure again if necessary.

CONCLUSIONS

Although group 1 had greater preoperative knee pain levels, their pain levels at 5 years postoperatively were comparable to those in group 2. With the exception of swelling, comparable improvements were observed between groups for all other variables.

LEVEL OF EVIDENCE

Level III, retrospective, case-control study.

Use of distal femoral osteoarticular allografts in limb salvage surgery. Surgical technique

BACKGROUND

As diagnostic and therapeutic techniques improve, patients with a musculoskeletal sarcoma should expect longer survival, fewer complications and side effects, and an improved quality of life. Functional longevity of the reconstruction after resection of the tumor becomes a major concern, especially in young and physically active patients. The purpose of this study was to analyze the mid-term and long-term survival of reconstructions with a distal femoral osteoarticular allograft in a series of patients.

METHODS

We retrospectively reviewed the results of eighty reconstructions with a distal femoral osteoarticular allograft following resection of a bone tumor in seventy-six patients. The mean duration of follow-up was eighty-two months. The rates of survival of the allograft and the joint surface were estimated with use of the Kaplan-Meier method. Cox regression analysis was performed to determine whether age, gender, the percentage of the femur that had been resected, and the use of chemotherapy were independent prognostic factors. Functional and radiographic results were documented according to the Musculoskeletal Tumor Society scoring system at the time of the latest follow-up.

RESULTS

Five patients were lost to follow-up, leaving seventy-five allografts in seventy-one patients available for study. Thirteen patients (thirteen allografts) died of tumor-related causes without allograft failure before a two-year radiographic follow-up could be performed. Of the remaining sixty-two allografts, fourteen failed: six failed as a result of infection; four, because of local recurrence; one, because of massive resorption; and three, as a result of fracture. At the time of final follow-up, at a mean of 125 months, forty-eight allografts were still in place. The overall rate of allograft survival was 78% at both five and ten years, and the rate of allograft survival without the need for resurfacing with a knee prosthesis was 71% at both five and ten years. With the numbers available, age, gender, the percentage of the femur that had been resected, and the use of chemotherapy were not found to have a significant effect on the overall allograft survival rates. The patients who retained the original allograft had good or excellent functional and radiographic results.

CONCLUSIONS

The life expectancy for most patients with a highly aggressive or malignant tumor in the distal part of the femur is now several decades. In this study, we found a high rate of survival of distal femoral allograft reconstructions at both five and ten years.

Mapping of donor and recipient site properties for osteochondral graft reconstruction of subchondral cystic lesions in the equine stifle joint

REASONS FOR PERFORMING STUDY

To improve osteochondral graft reconstruction of subchondral cystic lesions in the medial and lateral femoral condyles by matching the material properties of donor and recipient sites.

OBJECTIVES

To measure biomechanical and biochemical parameters that influence the function and healing of osteochondral grafts used to reconstruct subchondral cystic lesions.

HYPOTHESIS

Suitable donor sites are available within the stifle joint for reconstructing the femoral condyles, despite considerable regional property variation.

METHODS

Fifty-six osteochondral cores were harvested from 6 distal femurs for initial studies that determined subchondral bone modulus of elasticity and ultimate stress. In a second study, 28 osteochondral cores were harvested from 6 distal femurs to measure cartilage aggregate modulus, thickness and sulphated glycosaminoglycan (sGAG) content. Using micro-CT imaging, subchondral bone mineral density and bone volume fraction were also measured. In both studies 2-dimensional contour plots using a bicubic interpolation method and normalised data were generated to allow visual comparison of joint surface characteristics. Statistical comparisons between donor and recipient site raw data were made using an ANOVA for repeated measures with a post hoc Tukey test.

RESULTS

Material properties of cartilage and bone vary considerably over the surface of the stifle joint but the central region of the medial condyle, where subchondral cystic lesions freqdently occur, typically demonstrated bone strength and modulus values of the highest observed. Cartilage thickness and aggregate modulus were highest in the medial femoral condyle and axial aspect of the lateral condyle.

CONCLUSIONS

Material properties of the grafts from the trochlear groove and axial aspect of the lateral trochlear ridge were the closest match for those found in the medial condyle, whereas properties of the lateral condyle were most similar to those found in the trochlear groove and axial aspect of the medial trochlear ridge.

Autologous osteochondral mosaicplasty for capitellar osteochondritis dissecans in teenaged patients

BACKGROUND

Autologous osteochondral mosaicplasty is a new technique to provide hyaline repair for articular defects. Although recent studies have reported the successful treatment of articular defects in the knee and ankle joints with this surgical procedure, little attention has been given to the surgical efficacy of mosaicplasty in the treatment of osteochondritis dissecans of the humeral capitellum.

PURPOSE

To clarify the clinical outcomes of mosaicplasty for teenaged patients with advanced lesions of capitellar osteochondritis dissecans.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Eight teenaged patients with advanced lesions of capitellar osteochondritis dissecans underwent mosaicplasties. All patients were baseball players who were affected on the right side, which was also their throwing side. The surgical technique involves obtaining small-sized cylindrical osteochondral grafts from the lateral periphery of the femoral condyles and transplanting them to prepared osteochondral defects. At a mean follow-up of 24 months, all patients were evaluated clinically and radiographically.

RESULTS

Seven of the 8 patients were free from elbow pain, and the remaining patient had mild pain occasionally. The mean clinical score described by Timmerman and Andrews (a maximum of 200 points) significantly improved from 140 points to 183 points postoperatively. All patients except one had excellent or good clinical results. Radiographically, the graft incorporation and a normal contour of the subchondral cortex were found in all patients. Magnetic resonance imaging showed that the preoperative heterogeneity of the lesion had disappeared and the signal intensity returned to normal. Six of the 8 patients, including all 3 pitchers, returned to competitive-level baseball.

CONCLUSION

Mosaicplasty for advanced lesions of capitellar osteochondritis dissecans in teenaged baseball players can provide satisfactory clinical and radiographic results.