Treatment outcomes for infected juxta-articular knee nonunions.

PURPOSE: This retrospective case series assessed the results of a treatment protocol for patients with infected para-articular knee nonunions. The aim was to demonstrate that knee function and quality-of-life (QoL) can be improved. CASE SERIES: Between January 2001 and December 2011, eleven patients with septic proximal tibial nonunion and seven with septic distal femoral nonunion were managed at our institution. The treatment protocol included extensive debridement, skeletal stabilization, culture-specific antibiotic administration, and soft-tissue and bone-deficit reconstruction. Knee function was evaluated with the Knee Society Score (KSS) while the Knee injury and Osteoarthritis Outcome Score (KOOS) and SF-12 were used for QoL assessment at a mean follow-up of 37.2 (range: 12-149) months. Seventeen nonunions healed at a mean of 21.9 weeks. One patient needed above knee amputation. Knee Society function and knee scores were improved significantly, from 16.7 and 33.8, to 75.0 and 84.9 respectively (p <0.001). KOOS outcome and SF-12 physical and mental components scores confirmed the QoL improvement. CONCLUSIONS: Staged management can improve QoL and functional knee outcome. HIPPOKRATIA 2018, 22(4): 183-187.

An Experimental Model on the Biomechanical Behaviour of the Flexor Tendons in New Zealand Rabbits.

BACKGROUND: In order to introduce new pharmacological agents with the intent to inhibit the adhesion formation, it is important to test such products on laboratory animals under a protocol that can evaluate the quantitative and qualitative aspects of healing of the tendons. Most experimental models focus on the tensile strength and histological analysis of the tendons, failing to sufficiently quantify the degree of the adhesion formation. METHODS: The experiment included six male New Zealand rabbits that underwent surgery of their right forepaws. The deep flexor tendon of the middle finger was transected and repaired and after six weeks the rabbits were killed. In order to assess the extent of adhesions, the functional stiffness of the tendons and the range of motion of the specimens' fingers was studied using a tensile testing machine. The setup used allowed the simultaneous recording of the specimens' motion and the pulling force values. RESULTS: The mean values of the left and right forepaws were expressed in the same chart showing a clear difference between the operated and non operated forepaws. CONCLUSIONS: Using a relatively simple set up in the laboratory we had the chance to focus on a more elaborate analysis of the data with the help of low cost and accessible software.

Histological and biochemical evidence related to the collagen quality in torn rotator cuff tendons.

This study investigates the histological background of torn rotator cuff tendons, evaluates the stability of newly synthesized collagen by measuring the hydro-xyproline content and attempts to correlate these findings with the clinical outcome after reconstruction of the rotator cuff. Sixty-one patients underwent reconstruction for a -rotator cuff tear. They were evaluated preoperatively with the Constant-Murley score, MRI and ultrasound. Biopsy samples were taken from chronic rotator cuff tears and histological analysis was performed. Hydroxyprolin presence was evaluated in various -tissues. Mean follow-up was 46 months. Histological analysis revealed collagen fragmentation and thinning (90.2% of patients), myxoid degeneration (88%), hyaline degeneration (50.8%), chondroid metaplasia (44.3%), calcification (24.7%), fatty infiltration (20.4%) and vascular proliferation (62.3%). Hydroxyproline was under-represented in newly synthesized collagen in 57% of patients. In the majority of the patients with a low hydroxyproline/collagen ratio the histological findings were abnormal. None of the findings was related to the clinical outcome with a statistical significance. Histological and biochemical findings reflected the poor quality of the tendon. The good clinical outcome did not depend on the histological or biochemical findings but rather on the meticulous surgical reconstruction and physical therapy.

An 11- to 15-year clinical outcome study of the Advance Medial Pivot total knee arthroplasty: pivot knee arthroplasty.

AIMS: The Advance Medial-Pivot total knee arthroplasty (TKA) was designed to reflect contemporary data regarding the kinematics of the knee. We wished to examine the long-term results obtained with this prosthesis by extending a previous evaluation. PATIENTS AND METHODS: We retrospectively evaluated prospectively collected data from 225 consecutive patients (41 men and 184 women; mean age at surgery 71 years, 52 to 84) who underwent 284 TKAs with a mean follow-up of 13.4 years (11 to 15). Implant failure, complication rate, clinical (both subjective and objective) and radiological outcome were assessed. Pre- and post-operative clinical and radiographic data were available at regular intervals for all patients. A total of ten patients (4.4%; ten TKAs) were lost to follow-up. RESULTS: Survival analysis at 15 years showed a cumulative success rate of 97.3% (95% confidence interval (CI) 96.7 to 97.9) for revision for any reason, of 96.4% (95% CI 95.2 to 97.6) for all operations, and 98.8% (95% CI 98.2 to 99.4) for aseptic loosening as an end point. Three TKAs (1.06%) were revised due to aseptic loosening, two (0.7%) due to infection, one (0.35%) due to instability and one (0.35%) due to a traumatic dislocation. All patients showed a statistically significant improvement on the Knee Society Score (p = 0.001), Western Ontario and McMaster University Osteoarthritis Index (p = 0.001), Short Form-12 (p = 0.01), and Oxford Knee Score (p = 0.01). A total of 207 patients (92%) were able to perform age appropriate activities with a mean flexion of the knee of 117° (85° to 135°) at final follow-up. CONCLUSION: This study demonstrates satisfactory functional and radiographic long-term results for this implant. Cite this article: Bone Joint J 2016;98-B:1050-5.

RhBMP-7 for the treatment of nonunion of fractures of long bones.

We report the outcome of 84 nonunions involving long bones which were treated with rhBMP-7, in 84 patients (60 men: 24 women) with a mean age 46 years (18 to 81) between 2003 and 2011. The patients had undergone a mean of three previous operations (one to 11) for nonunion which had been present for a mean of 17 months (4 months to 20 years). The nonunions involved the lower limb in 71 patients and the remainder involved the upper limb. A total of 30 nonunions were septic. Treatment was considered successful when the nonunion healed without additional procedures. The relationship between successful union and the time to union was investigated and various factors including age and gender, the nature of the nonunion (location, size, type, chronicity, previous procedures, infection, the condition of the soft tissues) and type of index procedure (revision of fixation, type of graft, amount of rhBMP-7) were analysed. The improvement of the patients' quality of life was estimated using the Short Form (SF) 12 score. A total of 68 nonunions (80.9%) healed with no need for further procedures at a mean of 5.4 months (3 to 10) post-operatively. Multivariate logistic regression analysis of the factors affecting union suggested that only infection significantly affected the rate of union (p = 0.004).Time to union was only affected by the number of previous failed procedures (p = 0.006). An improvement of 79% and 32.2% in SF-12 physical and mental score, respectively, was noted within the first post-operative year. Rh-BMP-7 combined with bone grafts, enabled healing of the nonunion and improved quality of life in about 80% of patients. Aseptic nonunions were much more likely to unite than septic ones. The number of previous failed operations significantly delayed the time to union.

Surgical treatment of hip fractures: factors influencing mortality.

BACKGROUND: Data for osteoporotic hip fractures in Greece is limited and little is known upon the meaning of family support during the postoperative/rehabilitation period. OBJECTIVE: To identify the factors influencing the mortality after hip fractures in the elderly, the effect of rehabilitation and family support in the post-fracture course, and the impact of these fractures on the family of the injured elderly. METHODS: We conducted an observational study of 218 consecutive patients older than 60 years of age, who underwent surgical management of a unilateral hip fracture at a tertiary hospital of Central Greece, with follow-up contacts at 30 days, 3 months and one year. Demographic characteristics, pre- and post-fracture residential and functional status, assessment of basic activities of daily living (ADL), co-morbidities, type and mechanism of fracture and hospitalization data as well as the modification of activities of the patients' relatives were recorded. RESULTS: Fifteen patients (6.9%) died during hospitalization; thirty-nine (17.9%) died within one year of fracture. The factors that were predictive of in-hospital, 30-days and one-year mortality, based on multivariate analysis, were male sex, advanced age >85 and Charson index >3. There was a significant association between delayed surgery (>48 hours) and increased in-hospital mortality. The percentage of patients assessed as ADL A or B at baseline, decreased form 84% preoperatively to 50.4% one year postoperatively. Only one-third of patients walking without aid before the fracture returned to the previous state. Family members modified their activities in 48% of cases to assist their relatives with a hip fracture. CONCLUSIONS: One-year mortality in patients with hip fractures was 17.9%. Surgical delay (>48 hours) increased in-hospital mortality. Comorbidities >3, male sex, and advanced age increased the risk of in-hospital and post-discharge mortality during the 1st year. Twelve months postoperatively, half of patients walking without aid before the fracture returned to the previous state. Despite the beneficial effect of family support, the lack of organized rehabilitation programs and geriatric units are potential negative factors for patients' functional outcome. In addition, 48% of patients' relatives changed their daily activities to assist their relatives.

Smoking affects mRNA expression of bone morphogenetic proteins in human periosteum.

Periosteum is important for bone homoeostasis through the release of bone morphogenetic proteins (BMPs) and their effect on osteoprogenitor cells. Smoking has an adverse effect on fracture healing and bone regeneration. The aim of this study was to evaluate the effect of smoking on the expression of the BMPs of human periosteum. Real-time polymerase chain reaction was performed for BMP-2,-4,-6,-7 gene expression in periosteal samples obtained from 45 fractured bones (19 smokers, 26 non-smokers) and 60 non-fractured bones (21 smokers, 39 non-smokers). A hierarchical model of BMP gene expression (BMP-2 > BMP-6 > BMP-4 > BMP-7) was demonstrated in all samples. When smokers and non-smokers were compared, a remarkable reduction in the gene expression of BMP-2, -4 and -6 was noticed in smokers. The comparison of fracture and non-fracture groups demonstrated a higher gene expression of BMP-2, -4 and -7 in the non-fracture samples. Within the subgroups (fracture and non-fracture), BMP gene expression in smokers was either lower but without statistical significance in the majority of BMPs, or similar to that in non-smokers with regard to BMP-4 in fracture and BMP-7 in non-fracture samples. In smokers, BMP gene expression of human periosteum was reduced, demonstrating the effect of smoking at the molecular level by reduction of mRNA transcription of periosteal BMPs. Among the BMPs studied, BMP-2 gene expression was significantly higher, highlighting its role in bone homoeostasis.

Early results of a novel technique using multiple small tantalum pegs for the treatment of osteonecrosis of the femoral head: a case series involving 26 hips.

The introduction of a trabecular tantalum rod has been proposed for the management of early-stage osteonecrosis of the femoral head but serves as a single-point of support of the necrotic lesion. We describe a technique using two or three 4.2 mm (or later 4.7 mm) tantalum pegs for the prevention of collapse of the necrotic lesion. We prospectively studied 21 patients (26 hips) with non-traumatic osteonecrosis of the femoral head treated in this manner. Of these, 21 patients (24 hips) were available for radiological and clinical evaluation at a mean follow-up of 46 months (18 to 67). Radiological assessment showed that only eight hips deteriorated according to the Association Research Circulation Osseous classification, and four hips according to the Classification of the Japanese Investigation Committee of Health and Welfare. Functional improvement was obtained with an improvement in the mean Harris hip score from 65.2 (33.67 to 95) to 88.1 (51.72 to 100), the mean Merle D'Aubigné-Postel score from 13 (6 to 18) to 16 (11 to 18), a mean visual analogue score for pain from 5.2 (0 to 9.5) to 2.6 (0 to 7), and the mean Short-Form 36 score from 80.4 (56.8 to 107.1) to 92.4 (67.5 to 115.7). Of these 24 hips followed for a minimum of 18 months, three were considered as failures at the final follow-up, having required total hip replacement. One of the hips without full follow-up was also considered to be a failure. In more than two-thirds of the surviving hips a satisfactory clinical outcome was achieved with promising radiological findings. The estimated mean implant survival was 60 months (95% confidence interval 53.7 to 66.3).

Complex regional pain syndrome type I as a consequence of trauma or surgery to upper extremity: management with intravenous regional anaesthesia, using lidocaine and methyloprednisolone.

Complex regional pain syndrome type I (CRPS-I) is a known complication after surgery or trauma to the upper extremity and is difficult to treat. A simple and easily tolerated method of treatment that includes intravenous regional anaesthetic block with lidocaine and methyloprednisolone is presented. One hundred and sixty-eight patients with CRPS-I of the upper extremity were treated in a 5-year period. At the end of treatment 88% of the patients reported minimal or no pain. After a mean follow-up of 5 years (range 28 months to 7 years) complete absence of pain was reported by 92% of patients. The symptoms of the acute phase of the syndrome were reversed. Early recognition and prompt initiation of treatment is very important for the course of the disease as symptoms can be reversible when treatment starts early. Permanent results with a functional upper extremity and very satisfactory pain relief can be anticipated.

Skeletal muscle hydatid cysts presenting as soft tissue masses.

Muscle hydatidosis is rare, accounting only for 3-5% of all cases. We present a case series of 9 patients (8 male, one female, mean age 59.3 years, range 48-75 years) with primary echinococcosis of skeletal muscles. The cysts presented as soft tissue masses in 8 patients, whereas in one, the cyst was an incidental finding on a CT scan performed for investigation of a lung problem. All hydatid cysts were confined into muscles, without affecting the bone. The location was the thigh region in 6 patients (quadriceps in 4, biceps in 2), the popliteal fossa (gastrocnemius) in one, the humerus (triceps branchii) in one and the shoulder (infraspinatus) in one patient. MRI showed multi-vesicular cysts in all patients. Indirect hemagglutination serological test was positive in 6 out of 9 cases. En block surgical excision of the cysts was undertaken in all patients. Two patients received antihelminthic chemotherapy preoperatively. Histopathologic findings confirmed the diagnosis. No recurrence occurred during the follow-up period (1-8 years). Skeletal muscle echinococcosis should be considered in the differential diagnosis of limb masses, especially in endemic countries. A meticulous history taking and MRI imaging are essential, while pericystectomy is an effective method of treatment.

Use of a mini-external fixator for the treatment of hand fractures.

PURPOSE: To evaluate the outcome of hand fractures managed with mini-external fixators (MEFs) in order to assess their usefulness in different fracture types and to make recommendations regarding potential applications. METHODS: Fifty-one patients with 59 metacarpal and phalangeal fractures were treated with MEFs. Fixators were used to reduce the fracture or to achieve volar plate arthroplasty when anatomical joint reconstruction was impossible. The mean period from injury to MEF application was 4.5 days. RESULTS: The procedure was performed using regional anesthesia and fluoroscopic control, and it lasted 20 to 45 minutes. MEFs were removed in a mean period of 6 weeks, and follow-up was 18 to 55 months. Forty-nine patients with 57 fractures remained in the follow-up group. In all cases the skeleton was successfully reconstructed, whereas the clinical outcome varied according to the type of the original injury: intra-articular fractures had worse outcome than extra-articular (p=.035 for grip strength and p=.0005 for total active motion), and open fractures had worse outcome than closed (p=.06 for grip strength and p=.001 for total active motion). In all cases, patients' satisfaction was high; the Disabilities of the Arm, Shoulder, and Hand score was <7.9 and the visual analog scale score was <0.5. CONCLUSIONS: The findings of this series demonstrate the efficacy of versatile MEFs to establish union and correct alignment of hand skeleton with minimal tissue trauma while retaining a good clinical outcome even in the most complex injuries. MEFs can be considered for all hand fractures requiring surgical treatment, and especially for the intra-articular and comminuted fractures. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Injection injuries: seemingly minor injuries with major consequences.

BACKGROUND: High-pressure injection injuries are rare injuries, characterized by a small puncture wound that is often underestimated by physicians and patients. The injected substance leads to extensive tissue damage and sometimes to loss of the limb. AIM: To underline the severity of these injuries and to alert physicians to recognize them and treat them appropriately. METHODS: Eight patients with injection injuries from lubricants (6) or solvents (2) were treated in a University Orthopaedic Department in a 5-year period. In all patients the mild initial symptoms were aggravated over the next 4-6 hours leading to a severe compartment syndrome of the hand. Five patients were referred with a mean delay of 3.8 days and 3 were treated immediately; all with debridement and compartment release. RESULTS: The total number of procedures per patient was 2 to 5. In 3 patients a heterodigital flap was necessary whereas in one the second ray was amputated. Results were excellent in 5 cases and good in 3. CONCLUSIONS: In injection injuries, prompt diagnosis and immediate aggressive surgical intervention are necessary to save the patients' digit/limb. Patients should be informed about the severity of their injury, its potential complications and the multiple surgical procedures that may be required for a satisfactory functional result.

Treatment of intra-articular fractures of the distal radius: fluoroscopic or arthroscopic reduction?

In a randomised prospective study, 20 patients with intra-articular fractures of the distal radius underwent arthroscopically- and fluoroscopically-assisted reduction and external fixation plus percutaneous pinning. Another group of 20 patients with the same fracture characteristics underwent fluoroscopically-assisted reduction alone and external fixation plus percutaneous pinning. The patients were evaluated clinically and radiologically at follow-up of 24 months. The Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire and modified Mayo wrist score were used at 3, 9, 12 and 24 months postoperatively. In the arthroscopically- and fluoroscopically-assisted group, triangular fibrocartilage complex tears were found in 12 patients (60%), complete or incomplete scapholunate ligament tears in nine (45%), and lunotriquetral ligament tears in four (20%). They were treated either arthroscopically or by open operation. Patients who underwent arthroscopically- and fluoroscopically-assisted treatment had significantly better supination, extension and flexion at all time points than those who had fluoroscopically-assisted surgery. The mean DASH scores were similar for both groups at 24 months, whereas the difference in the mean modified Mayo wrist scores remained statistically significant. Although the groups are small, it is clear that the addition of arthroscopy to the fluoroscopically-assisted treatment of intra-articular distal radius fractures improves the outcome. Better treatment of associated intra-articular injuries might also have been a reason for the improved outcome.

Purulent flexor tenosynovitis: factors influencing the functional outcome.

This retrospective study aimed to evaluate the factors that influence the final outcome of treatment of purulent flexor tenosynovitis, viz. delay in treatment, severity of the condition, the infecting pathogen and the method of treatment. Of 41 patients with this condition treated by drainage and irrigation through two small incisions (16) and wide incision (25), 16 were treated after a delay. Continuous postoperative irrigation was applied in 26 patients. Re-operation was necessary in 11 patients. In most cases, Staphylococcus aureus was detected. The results were excellent in 32 cases and the mean Disabilities of the Arm, Shoulder and Hand score was 8.1. Irrigation through small incisions and continuous postoperative irrigation decreased the probability of an unfavourable outcome. Delayed treatment and infections with specific pathogens led to a worse outcome. Early diagnosis of purulent flexor tenosynovitis followed by drainage through small incisions and continuous postoperative irrigation appear, from this retrospective review, to lead to the best functional outcome.

Restoration of function and sensitivity utilizing a homodigital neurovascular island flap after amputation injuries of the fingertip.

Sixty-three fingertip amputations in 50 patients were reconstructed using a homodigital neurovascular island flap technique based on a single neurovascular pedicle without further shortening of the distal phalanx. The procedure was carried out under regional anaesthesia, using a tourniquet and magnifying loupes. All of the flaps survived and achieved normal or adequate two-point discrimination without any painful scar or cold hypersensitivity. Fifteen patients had some loss of distal interphalangeal joint extension. The technique is simple and presents an excellent method for fingertip reconstruction in Allen type II, III and IV injuries.

Scaphoid nonunions treated with vascularised bone grafts: MRI assessment.

PURPOSE: To assess the value of MR imaging (MRI) with regard to union, graft viability and proximal pole bone marrow status, after use of vascularized bone grafts for treating scaphoid nonunions. MATERIALS AND METHODS: Vascularized bone grafts from the distal radius were used to treat 47 scaphoid nonunions resulting from fractures or enchondromas. Clinical and imaging evaluation was used for the pre- and postoperative assessment of all patients. Apart of conventional radiographs obtained in all cases, 15 patients were also assessed postoperatively with MRI at 3 months. From these 15 patients, eight were assessed preoperatively with MRI whereas nine had serial MRI evaluations at 6 and 12 months. The clinical follow-up time of this subgroup of 15 patients ranged from 6 to 27 months. RESULTS: All patients showed clinical signs of union within 12 weeks form the procedure and at the latest follow-up they experienced complete (10 cases) or almost complete (five cases) relief from pain. Both plain and contrast-enhanced MRI obtained at 3 months showed viability of the bone graft in all cases. At 3 months union was established with plain radiographs in 12 patients at both sides of the graft and in three patients between the graft and proximal pole. At 3 months plain MRI showed nonunion in four patients (two between graft and proximal pole, two between graft and distal pole and one at both sides of the graft) whereas contrast-enhanced MRI revealed only one case of nonunion between graft and proximal pole. Four patients were considered to have osteonecrosis of the proximal pole intraoperatively. Two of them showed necrosis of the proximal pole with preoperative and postoperative plain radiographs and three of them with plain postoperative MRI. Contrast-enhanced MRI at 3 months showed postoperative reversal of necrotic changes in all four scaphoids. MRI also revealed bone marrow oedema of the carpal bones surrounding the scaphoid in 14 cases. Serial MRI at 6 and 12 months, obtained in nine patients, revealed resolution of the bone marrow oedema of the surrounding bones and full graft incorporation in all cases. CONCLUSION: Contrast-enhanced MRI is able to demonstrate the early union after treatment of scaphoid nonunions with vascularised bone grafts allowing thus earlier mobilisation. In addition, MRI can assess the viability of the proximal pole and the graft as well as the postoperative bone marrow oedema-like lesions of the surrounding bones.

Partial rupture of the distal biceps tendon.

We report on 7 cases of partial rupture of the distal biceps tendon. The mean patient age was 52 years (range, 38-58 years). There were 5 men and 2 women. The dominant arm was affected in all 7 patients. Pain was the chief complaint in all patients. Immobilization and physiotherapy were attempted in all patients, and 4 had at least 1 local steroid injection. No patient improved from the conservative treatment. All patients eventually underwent surgical debridement and reattachment of the biceps tendon with use of a 1-incision technique with suture anchors. After a mean follow-up of 31 months (range, 25-44 months), all patients reported a significant decrease in their pain. No complications were noted.

Classification of osteonecrosis of the femoral head. Reliability, reproducibility, and prognostic value.

The purpose of the current investigation was to determine interobserver and intraobserver reliability of the classification system of Steinberg et al for osteonecrosis of the femoral head. Sixty-five anteroposterior and lateral radiographs of hips were selected randomly from a pool of patients with confirmed osteonecrosis of the femoral head. Six fellowship-trained observers viewed the radiographs (Reading 1). The observers used six main stages of the classification excluding A, B, and C subgroups. The same observers viewed the radiographs 4 months later in reverse order (Reading 2). Reading 1 was used to calculate interobserver kappa values. Reading 2 was used to calculate intraobserver kappa values. Stage-specific kappa values for interobserver variation between all viewers were as follows: Stage I, k = 0.64; Stage II, k = 0.51; Stage III, k = 0.21; Stage IV, k = 0.49; Stage V, k = 0.36; and Stage VI, k = 0.80. Stage-specific kappa values for intraobserver variation between all viewers were as follows: Stage I, k = 0.74; Stage II, k = 0.60; Stage III, k = 0.46; Stage IV, k = 0.59; Stage V, k = 0.27; and Stage VI, k = 0.78. An average of 10 of 21 (48%) of these errors involved Stage III. An average of 6.3 of 21 (30%) intraobserver errors involved Stage V. The presence of the crescent sign in Stage III and joint space narrowing in Stage V markedly diminished the overall reliability of any four- to six-stage classification system. Based on the authors' experience and analysis of the current classifications of osteonecrosis of the femoral head, an easy and reproducible Pittsburgh classification system is proposed.

Treatment of recurrent compressive neuropathy of peripheral nerves in the upper extremity with an autologous vein insulator.

The treatment of entrapment neuropathy in the upper extremity with surgical decompression has generally provided good results. Recurrence of symptoms, however, is not uncommon and its management is both challenging and difficult. Nineteen patients with recurrent carpal tunnel and cubital tunnel syndrome were treated with the vein wrapping technique using the autogenous saphenous vein. The average number of surgeries before vein wrapping was 3.3. The mean patient age was 53 years (range, 28-75 years) and the mean follow-up period was 43 months (range, 24-78 months). All patients reported reduction in pain and the sensory disturbances secondary to the compression of the median or ulnar nerve. Two-point discrimination and electrodiagnostic findings also improved.

Vascularized orthotopic osteochondral transplantation of the canine proximal femur.

Osteochondral vascularized proximal femoral allografts were orthotopically transplanted in five adult beagles (four experimental and one control). The experimental animals were placed on 0.1 mg/kg of FK506 intravenously for 7 days, and then converted to 1.0 mg/kg orally. Biopsies of the femoral heads were taken at 3 weeks postoperatively and at 1-month intervals thereafter. The specimens were studied histologically with a hemotoxylin and eosin staining technique. Bone biopsies showed no microscopic evidence of rejection, and only minimal evidence of necrosis. Patency of the microvascular anastomosis was confirmed with bone scanning, using technitium 99m phosphate, arteriograms, and by Doppler flowmeter. All animals had an uneventful postoperative course, with achievement of full weight-bearing status by postoperative day 10, and normal activity by 1 month postoperatively. There were no infections or hip dislocations. One animal sustained a femoral neck fracture and was sacrificed at 4 months. At 6 months, the remaining animals were sacrificed. At necropsy, the experimental animals and the normal dog showed viable chondrocytes and osteocytes, with minimal bone necrosis. No dislocations or allograft rejections were observed. Based on this small series, a successful technique has been developed for orthotopic transplantation of a vascularized hip joint in a canine model.