We evaluated the efficacy of using the expandable nail for treating non-union and malunion of the tibial and femoral shafts. Records of 20 patients were retrospectively reviewed: 12 had femoral non-union, 7 had tibial non-union, and one had tibial malunion. The bones underwent reaming and the largest possible nail sizes were inserted during reoperation.

The mean age of the patients was 35 years (26-49) in the tibia group and 53 years (23-85) in the femur group. The fractures were defined according to AO/OTA classification and divided between open and closed. The initial treatment was 6 interlocking intramedullary nails and 2 external fixation in the tibia group, and 6 interlocking intramedullary nails, 3 plates and screws and 2 proximal femoral nails in the femoral group. The respective intervals between the original trauma and re-operation were 12 months and 15 months and the respective operation times were 59 minutes (35-70) and 68 minutes (20-120).

All fractures healed satisfactorily without the need for an additional procedure. Healing time was 26 weeks (6-52) and 14 weeks (6-26) in the tibia and femur group, respectively. Limb shortenings of 10cm and 4cm were recorded in one patient each in the tibia group and of 3cm in one patient in the femur group.

Using the expandable nail system permitted us to ream the bone and expand the nail to its maximal diameter, i.e. up to 16mm in the tibia and 19mm in the femur. We believe that using a bigger nail diameter contributes to better stabilisation of the fracture and promotes better and faster bone healing.

Based on our experience, we recommend the use of the expandable nail system to treat tibia and femur shaft non-unions and malunions.

We evaluated the efficacy of using the expandable nail for treating non-union and malunion of the tibial and femoral shafts.

Records of 20 patients were retrospectively reviewed: 12 had femoral non-union, 7 had tibial non-union, and one had tibial malunion. The bones underwent reaming and the largest possible nail sizes were inserted during reoperation.

The mean age of the patients was 35 years (26–49) and in the tibia group and 53 years (23–85) in the femur group. The fractures were defined according to AO/OTA classification and divided between open and closed. The initial treatment was 6 interlocking intramedullary nails and 2 external fixation in the tibia group, and 6 interlocking intramedullary nails, 3 plates and screws and 2 proximal femoral nails in the femoral group. The respective intervals between the original trauma and re-operation were 12 months and 15 months and the respective operation times were 59 minutes (35–70) and 68 minutes (20–120).

All fractures healed satisfactorily without the need of an additional procedure. Healing time was 26 weeks (6– 52) and 14 weeks (6–26) in the tibia and femur group, respectively. Limb shortenings of 10 cm and 4 cm were recorded in one patient each in the tibia group and of 3 cm in one patient in the femur group.

Using the expandable nail system permitted us to ream the bone and expand the nail to its maximal diameter, i.e., up to 16 mm in the tibia and 19 mm in the femur. We believe that using a bigger nail diameter contributes to better stabilization of the fracture and promotes better and faster bone healing.

Based on our experience, we recommend the use of the expandable nail system to treat tibia and femur shaft non-unions and malunions.

Medial transfer of the tibial Tuberosity remains the treatment of choice for skeletally mature patients with patellar malalignment (recurrent dislocation, subluxation with or without patellar tilt). As many patients with patellar malalignment have patellar articular cartilage lesion or patella alta, anteriorisation and distalisation of the tibial tuberosity is advised.

Material and Methods: Tibial tuberosity transfer was performed in our center on 80 knees in 66 patients (40 females, 26 males) during the past 13 years (mean age 23 range 15 – 52). One surgeon supervised all the operations. The average follows-up was 6.2 years (one to thirteen years). All patients were examined clinically for the purpose of this study. The Lisholm and Karlsson scoring system were used to evaluate the results. Radiographs of both knees were also taken. Fifteen knees had no dislocation of the patella prior to the operation, seventeen knees had 1 to 10 eleven knees had 10 to 50, ten knees 50 to 100, and twenty-seven knees had more than hundred dislocations of the patella prior to surgery. Ten of these knees had daily dislocations of the patella.

All operations were done either by selective epidural anesthesia (only sensory and not motor) or general anesthesia without muscle relaxant using quadriceps muscle stimulation. The mean tibial tuberosity medialisation, anteriorisation and distalisation was 1.4 cm (0–2.5 cm) 0.4cm (0–1.1cm) and 0.87cm (0–1.2cm) respectively.

Results: When interviewed by an independent examiner 87% of the patients reported improvement and only 4.3% (3 patients) reported worsening of their condition after the operation.

84% of the patients stated they would have the operation again. All patients had full active range of motion on both knees without extension lag.

At the final evaluation visit the Lisholm and Karlsson scores were good and excellent in 72% and 72.5%, 18.8% and 23.5% had fair results and only 8.7% and 4.4% had poor results respectively. The poor results correlated well with the degree of the patella cartilage damage found during surgery, poor selection of patients and extreme ligamentous laxity. There were two complications: one non-union of the tibial tuberosity treated successfully with bone grafting and one non displaced fracture bellow the osteotomy, treated conservatively. Both had excellent results.

Conclusion: We conclude that distal patella re-alignment done by tibial tuberosity transfer is a reliable technique for the treatment of patello femoral pain secondary to mal-alignment.

Study Design: The effect of Total Hip Replacement surgery (THR) upon spinal sagittal alignment and low back pain was assessed in patients with severe hip osteoarthritis.

Summary of Background Data: Osteoarthritis in the hip joint is associated with abnormal posture and gait due to hip flexion contracture and hip pain. This in turn may cause abnormal spinal sagittal alignment and secondarily induce low back and leg pain. However, there have been no reports regarding the corrective effect of Total Hip Replacement surgery upon spinal sagittal alignment in patients with osteoarthritis of the hip.

Methods: This study prospectively analyzed the results of 25 patients (15 females and 10 males, average age 67.4 years (32–84)) undergoing THR for severe osteoarthritis of the hip. Pre and post-surgical assessment included; sagittal measurement of Sacral Inclination (SI) and total Lumbar Lordosis (L1-S1) on standing lateral radiographs. Functional clinical outcomes for hip as well as low back were also evaluated using the Oswestry back Questionnaire, the Modified Harris Hip Score and Visual Analog Scale for lower back pain and hip pain accordingly.

All the radiographic and clinical evaluations were completed both before THR surgery and 3 months following the surgery during routine follow up.

Results: Mean Lumbar Lordosis before the surgery and in the follow up was 50.36 and 50.32 respectively. Mean sacral inclination before and after surgery were 39.06 and 38.16 respectively. Mean Functional outcomes as assessed by the HHS score before and after the surgery were 45.74 and 81.8 respectively. Mean Oswestry Questionnaire scores before and after the surgery were 36.72 and 24.08 respectively. Mean VAS scores for hip pain before and after the surgery were 7.08 and 2.52 respectively. Mean VAS scores for lower back pain before and after the surgery were 5.04 and 3.68 respectively.

Discussion: No Significant difference was found between the sagittal alignment of the spine before THR and 3 months following it. Interestingly, total hip replacement surgery significantly improved spinal functional outcome as well as relieved low back and hip pain.

TOH was first described by Curtis and Kinkade in 1959, in women in the 3rd trimester of pregnancy. Later the disease was described in middle-aged males (4th-6th decade). Very rare occurrence was described in children and in females not connected to pregnancy.

Thirty-six patients with sudden hip pain with normal radiographs but increase uptake on bone scan and bone marrow edema in the head and neck on MRI were investigated by the senior author. Two patients (age 16 and 18) had Osteoid osteoma in the neck and two elderly patients (72 female and 75 male) had stress fracture in the neck were excluded from the study. The rest, 32 patients (28 males and 4 females – not connected to pregnancy) are the study group. Three male patients had bilateral involvement 1 to 3 years apart. The initial symptoms were pain, limping with minimal or no restriction in range of motion. All patients had plain radiographs, bone scan and MRI. Bone scan was positive in all and MRI showed bone edema in the neck and head in all. All patients were initially treated by non-weight bearing for six weeks followed by additional MRI every 6 weeks till the bone edema and symptoms subsided. In all patients the third MRI showed improvement in bone edema and were allowed to weight bear. None of the patients showed progression from TOH to AVN even in 7 patients with Crescent lines on T-1 images.

The mean F.U. was 51 months (4 to 131 months). Five patients still complained of mild pain in the affected hip, all with the exception of one had full range of motion. None of the patients had limping. All the plain radiographs were normal, with no signs of AVN or deformity of the head. In contrast the Dexa measurements of all patients showed decreased bone density in the affected hip compared to the other.

Conclusion: TOH is a benign disease. Even when Crescent lines are present all patients heal successfully without signs of AVN. Excellent correlation was found between subsidence of pain and improvement of bone edema on MRI. AVN and TOH are two distinct entities and therefore the treatment of TOH should always be conservative.

Objective: To evaluate and present our experience using the expandable nail system for the treatment of tibial shaft fractures.

Design: Retrospective study.

Setting: Level 1 Trauma Center – University teaching hospital.

Methods: Fifty-nine consecutive patients treated by this nail system for tibia fracture, fifty-four were acute fractures and five non-unions that were not included in the study. Two nail diameters were used, 8.5mm and 10mm. Operation, hospitalization and healing times, reaming versus non-reaming, isolated versus multiple injuries and re-operations were recorded and analyzed statistically.

Results All fractures healed in an average time of 72 days. The average healing times for patients treated with an 8.5 mm and 10 mm nail were 77.2 days and 63.4 days respectively. Average operative time was 103 minutes if reamed and 56 minutes if unreamed. Average healing times were 65.4 if reamed and 79.5 days if unreamed. Hardware was removed in 6 patients, and one patient underwent exchange nailing due to a delayed union. Operative time was shorter in the motor-vehicle group, 74 minutes in comparison to 80 and 84 minutes for the fall and pedestrian group.

Conclusion: The expandable nail offers the theoretical advantages of improved load sharing and rotational control without the need for interlocking screws. This study demonstrates satisfactory healing and alignment for the treatment of tibial shaft fractures using this device.

Introduction: Long bone fracture treatment with interlocking intramedullary nails is associated with long operative procedures, re-operations and long periods of infirmity. We assessed the clinical and economical factors associated with tibial fracture fixation with interlocking nails in comparison to fixation with an expandable stainless steel intramedullary nail.

Methods: Eighty diaphysial tibial fractures were consecutively treated with either an interlocking intramedullary nail (n=53 patients) or an expandable nail (n=27 patients).

Results: The duration of surgery was 139 minutes with interlocking nails and 52.9 minutes with expandable nails (p< 0.001). Re-hospitalization and re-operations were required in 51% and 42% of patients with interlocking nails respectively, compared to one patient (3%) with an expandable nail (p< 0.0001). Complications related to the introduction of interlocking screws (e.g., neurological deficits, screw breakage and delayed or non-union requiring dynamization) occurred in 19 interlocking nail patients and in none of the expandable nail patients. Union was achieved after 17.5 weeks (mean) with the interlocking nails compared to 11.5 weeks for expandable nails (p=0.071). The beneficial economic ramifications of using expandable nails were a 39% reduction in hospital expenses.

Conclusions: The use of an expandable stainless steel intramedullary nail is associated with a substantial reduction in clinical complications and hospital costs. An expandable nail features a unique fixation modality, which has superior mechanical fixation strength and is better adapted to the physiological bone healing process.

Based on these advantages, as well as its simplicity in use and short surgical technique, we recommend it for treatment of long bone fractures.

Introduction: Meralgia paresthetica (MP) is a mononeuropathy of the lateral femoral cutaneous nerve, mainly associated with either injury or pressure to the nerve. Although this entity is well described, most clinical series have employed numerous treatment methods; therefore, the efficacy of individual modalities is unclear.

We describe our experience of 79 patients with complaints consistent with MP, treated, by the senior author, over a 13-year period.

Materials and Methods: Patients were managed in accordant to a structured protocol:

Initial management consisted of anti inflammatory agents, rest and redaction of aggravating factors.

Diagnostic nerve block test was carried out for those who were refractory to the above treatment. All patients who responded to the local anesthetic test were treated with local infiltration of corticosteroids.

Surgical intervention was reserved for patients who responded to the lidociane test but were refractory to repeated corticosteroids injections. Patients who failed to respond to the test injection were evaluated by CT-scan of the lumbar spine and by abdominal ultrasound (for female patients only). Follow-up ranged 1–13 years.

Results: Twenty-one patients (27%) reported satisfactory results flowing initial management. Local anesthetic yielded rapid relief of symptoms in 50 patients (86%), two additional patients responded to a second nerve block test (where a wider area was infiltrated).

In forty-two out of 52 patients (81%) who responded to the nerve block test and received treatment with corticosteroid injections, Long-lasting relief was obtained.

Three patients refractory to repeated injections of corticosteroid underwent surgery (neurolysis in one patient and nerve resection in two).

CT-scan of the lumbar spine revealed significant spinal stenosis and nerve root compression at the level of L1–3 in 3 out of 6 patients.

Conclusion: Idiopathic MP usually improves with nonoperative modalities. Temporary relief of symptoms following LFCN block is a specific diagnostic test, and is a good predictor of success following local corticosteroid injection. Surgery is seldom necessary and should be considered only if intractable pain persists despite such measures.

Purpose of Study: To evaluate the results of our first consecutive cases using Fixion nail for treatment of femoral shaft fractures.

Materials and Methods: Thirty consecutive patients treated at our department with the expandable Fixion nail for femoral fractures were evaluated in a prospective study. Demographic, preoperative, operative and follow-up data was collected from admission and out-patients files. The pre- and post-operative X-rays were evaluated by two senior authors to determine fracture classification (AO/ASIF-CCF), union and healing. This data was inserted into excel file for statistics and evaluation.

Results: The average age was 36 years. Fourteen fractures were due to MVA, 10-falls, 2-crush injuries, 2-non-unions, 1-pathological and one from gunshot wound. Six fractures were open. Twenty eight were middle shaft fractures and two were distal. Three primary nail diameters were used 8.5mm, 10mm and 12mm.

All fractures healed at an average time of 9.2 weeks (5–26) and for the open fractures 19 (12–26) weeks. Hardware was removed in 8 cases with no complications. In two cases re-operation was needed. In one early case the nail was fractured and replaced. In the second case the bone was circlaged due to fragmentation around the fracture site and a bigger nail was inserted few days later (wrong smaller nail was inserted previously).

Conclusions: This preliminary clinical study demonstrates our experience treating femoral fractures with Fixion nail. We find this nail to be simple for use and with satisfactory healing and alignment results.

No doubt that revision TKR is a challenging procedure. This procedure may be divided into three steps. First, a careful clinical examination is needed to assess range of motion, stiffness and possible difficulty in exposing and extracting the prosthesis. Second, an examination of joint stability is needed. Finally, radiographs should be evaluated for any bone deficiency that may require bone grafting or special prosthesis.

Exposure approaches may change in cases when second stage implantation is performed when an infected total knee replacement exists and when a cement spacer is used. In the cases when the cement spacer is left in place for a longer period of time, stiffness is much more prominent and therefore exposure may be even more difficult.

Subvastus and midvastus approaches are not suitable for this kind of revision. Usually in revision of total knee replacement or after cement spacer procedures, a larger exposure with the use of either snip incision, or osteotomy of the tibial tuberosity, or VY exposure is required. There are some cases where one can perform revision total knee without the extra exposure mentioned.

In revising total knee replacement, it is imperative that the joint line be restored to its original position. There are a few techniques that can be used to achieve this task by using a few landmarks. They include:

The residue of the menisci.

This can be done by comparing the other non-operated knee too.

The decision to which kind of prosthesis to use depends on the amount of bone loss and the injury to the surrounding structures and ligaments. One should be prepared for all options during surgery, in other words, using constrain or unconstraint prosthesis in the same patients. This depends solely on the findings during surgery.

In our hospital, we have used all the exposure approaches of the knee in revision surgery. We prefer the snip excision in the first stage, and if this is not sufficient then a tibial tuberosity osteotomy is preferred to the VY incision of the quadriceps mechanism. We found that using the meniscal residue is a very useful landmark for the joint line and we use it constantly.

The incidence of comminuted proximal femur fractures is increasing, due to the growing proportion of elderly people in the general population. Severely depleted cancellous bone in the femoral head and neck prevent stable proximal purchase, mandatory for intertrochanteric and subtrochanteric fractures. Osteoporotic bones are associated with high implant failure rates, evidenced by cutout and upward screw penetration of the hip joint.

A new method for femoral head fixation is described. The peg consists of a distal end that can expand in diameter from 7.8mm to 10.5mm by using pressurized saline, allowing good abutment into the femoral head. The peg may be connected to a side plate or an intramedullary device for inter or subtrochanteric fractures.

Materials and Methods: Ten femoral heads were retrieved from patients who underwent hip hemiarthroplasty due to subcapital fracture. The heads were covered with a transparent epoxy resin until full solidification was obtained. An 8mm drill-hole was used to drill from the distal femoral neck along the femoral head axis, not penetrating the subchondral bone and cartilage. Afterwards, 1.4mm drill was used to penetrate the cartilage and subchondral bone of the femoral head for insertion of a pressure gage. Intraosseous pressure measurements were then recorded. The peri-prosthetic bone density was evaluated by Dual Energy X-ray Absorptiometry (DEXA) and Microradiography Computer Analysis in two stages: 1) with the peg unexpanded, and 2) with the peg expanded. In addition, Instron 8871 tested axial load, pullout and rotatory strengths of the peg.

Results: Increased periprosthetic bone density following peg expansion was demonstrated on DEXA and microradiography with no increase in the intraosseous pressure. The friction coefficient of the bone implant interface, calculated by axial load measurements, was less than the coefficient of steel to steel. Pullout and rotatory strengths were as good as those reported for the Dynamic Hip Screw (DHS).

Conclusions: Bone stock preservation due to compression of the depleted cancellous bone (rather than removed bone by drilling) may improve the mechanical properties of the periprosthetic bone and the stability of the fixation. Due to the strong abutment of the peg, hardware failure, mainly bone cutout can be reduced. Due to its lower friction coefficient, the hip peg will begin to slide following axial load through the plate or the intramedullary device, rather than penetrating the femoral head.

Preliminary positive results indicate that this new method may be suitable for inter or subtrochanteric femoral fracture fixation.

Osteonecrosis (ON) around the knee joint can be spontaneous (primary), without comorbid medical conditions, or secondary. ON is characterized by sudden pain, usually self resolving after six months to a year, night pain, and involving mainly women older than 55 years of age.

Twenty seven patients with primary ON were retrospectively reviewed. The patients were evaluated clinically (physical examination and H.S.S. scoring) and radiographically (plain radiographs were done at the beginning and at the end of follow-up and MRI studies). The MRI study included calculations of the area and the volume of the lesion, osteoarthritic changes, bone collapse and meniscal pathologic findings.

The majority of the patients, 96% (26/27), complained of sudden pain. Night pain was observed in 46% of the patients. Osteoarthritic changes observed in 60% of the patients and further deterioration (37%) was noted at follow up radiographs. Osteoarthritic changes were more predominant in patients with tibial condyle involvement rather than those with femoral involvement, 61% vs. 43% (p=0.04), respectively. Diagnosis of osteonecrosis by the initial radiographs was more common in patients with femoral involvement (7 femurs vs. 1 tibia).

All ON lesions were diagnosed by MRI, from these, 17 meniscal tears (63%) were detected.

Several observations were noted in the volumetric analysis: Tibial lesions were larger than femoral lesions (8.1cm³ vs. 3.1cm³, respectively, p=0.026). Women had significantly larger lesions in volume and area than men (area – 5.09cm² vs 2.05cm², p=0.01; and volume – 6.6cm³ vs. 1.2cm³, p=0.001). Significant correlation was found between bone collapse and the need for total knee replacement (TKR): 40% collapse in the TKR patients versus 13.6% collapse without TKR (p=0.028). Patients that were diagnosed with collapse at the end of the follow up had a larger area (5.8cm² vs 3.7cm²) and a lower HSS score (68.5 points vs. 83 points, p=0.02) than those without. A significant correlation was noted between a larger lesion area and lower HSS scoring (p=0.037) at the end of the follow-up. Patients with tibial lesions had more meniscal pathologies involvement, 56.3% vs. 43.8%, however it was not statistically significant (p=0.68).

We conclude that MRI study for patients with ON and calculating the area and the volumetric data particularly, is an accurate predictive tool for the natural history of knee ON. The findings presented here may guide us in determining the best possible treatment.

Purpose of the Study: To determine the efficacy of using the Fixion Intramedullary Nail System – an inflatable, unreamed, self locking nail in humeral pathologic fracture stabilization. To our knowledge no clinical reports regarding this subject have been published.

Patients and Methods: The medical record and radiographs, of 14 patients treated with the “Fixion” Nail, since October 1999, for pathological or impending humeral fractures, were reviewed. Patients included 6 male and 8 female with mean age of 58.8 years (35–83). Skeletal survey or routine radiograms made diagnosis. Patients harboring tumors were evaluated with isotope bone scan. Loss of approximately 33% of the bone substance was the criteria for nailing procedure consideration. Nine acute pathological fractures and 5 impending fractures were treated. The fracture’s site distribution per distal, medial and proximal humeral shaft were as following: 1, 11, 2, accordingly. Nine patients were operated on via antegrade and 5 via retrograde.

All surgeries were minimally invasive using a single 2–4 cm skin incision.

Results: Excellent humeral anatomical reduction and stabilization were achieved in all patients. Reaming was needed in 4 patients (28.5%). No interlocking screws were used. Significant relief of pain and regained functionality were demonstrated. Average surgical time was 32.7 minutes (20–55). Mean X-Ray radiation time was 4.07 minutes (0.5–6.15). No wound dehisces or other complications were reported.

Conclusion: The unreamed in most of the cases, no interlocking screws, minimal invasiveness and high stabilization capacities in addition to perfect torsion resistance confer to this nail the ideal qualities to be used with excellent results in pathological fractures. Oncological patients that might be immunosuppressive due to different administered therapies could benefit from reduced postoperative infection rate because of minimizing entry point for infection.

Between the years 1999 and 2001, approximately 3000 expandable intramedullary nails were used worldwide in various surgical procedures. From this number, 250 of these nails were used for traumatic fractures and are the focus of the study presented here. The subjects consisted of 160 males and 90 females with a mean age of 41 years. Initial radiographs were obtained for all subjects. Additional X-rays and follow-up data were reported for only 75 patients (30%) with follow-up time averaging 18 weeks. Most of the fractures occurred in the midshaft (64%), followed by distal thirds (22%), and then proximal (14%). The group was then divided according to fracture location: humerus, tibial and femur.

The nail was used in 92 humerus fractures. Follow-up data was available for 35 patients with a follow-up time averaging 16 weeks. The nail was inserted retrograde in 61% of the patients and antigrade in 39% of the patients. Partial reaming was done in 42% of the cases. Mean operating time was 52 minutes and fluoroscopy time was 3.8 minutes. Anatomical reduction was achieved in 96% of the cases and in 4% of the cases, acceptable reduction was achieved with a varus < 10°. Surgical outcomes included 28 complete bone union, and 7 partial union. Eight nails were removed after complete union was achieved.

In addition, the inflatable nail was used for treatment of 114 tibial fractures. In 39% of the cases a partial reaming was done. Average operating time was 39 minutes and fluoroscopy time was 3.4 minutes. All the fractures were reduced anatomically. In 25 patients with mean follow-up of 18 weeks, 14 united completely and 11 united partially. Nine nails were removed after completion of the union.

Data on 44 patients with femoral fractures treated by the inflatable nail were also reported. Only 15 patients were available for follow-up with an average of 21 weeks follow-up time.

Nail insertion by the antegrade approach was used in 89% of the patients and the retrograde approach was used in 11% of the patients. Partial reaming was done in 44% of the cases.

Mean operating time was 60 minutes and fluoroscopy time 7.5 minutes. Anatomical reduction was achieved in all with the exception of two patients with mild valgus deformity (< 10°). By the end of the study period, 8 had complete union, 7 had partial union.

In summary, the nail was found to be very effective and safe. The surgeons who performed the surgery reported that surgical and fluoroscopy time were both reduced by half. Reaming was not mandatory and this contributed to the shortened operating time. No complications were encountered during extraction of all the nails after completion of union, even in those patients in whom the nail developed an hour glass configuration according to the size of the medullary canal.

It is still too early to conclude if this nail will produce better or equal results to the conventional interlocking nails. Nevertheless, the lack of reaming, locking, and the low contact area of the nail with the medullary canal, may explain the rapid healing observed in some cases.

The longitudinal arch between the heel and the forefoot and the transverse arch between the first and fifth metatarsal heads, absorb shock, energy and force. A device to measure plantar pressure was used in 66 normal healthy subjects and in 294 patients with various types of foot disorder. Only 22 (3%) of a total of 720 feet, had a dynamic metatarsal arch during the stance phase of walking, and all had known abnormality.

Our findings show that there is no distal transverse metatarsal arch during the stance phase. This is important for the classification and description of disorders of the foot.

In vitamin D-fed chicks 1,25-dihydroxyvitamin D3 and 24,25-dihydroxyvitamin D3 were implanted into experimentally-produced fractures of the mid-tibia. The mechanical and biochemical properties of the tibia were evaluated for two weeks, including torsion tests, measurement of alkaline phosphatase activity, 45Ca incorporation, and Ca2+ content. Both dihydroxylated metabolites of vitamin D3 had a direct effect on endochondral bone formation. 24,25(OH)2D3 strengthened the callus, and raised alkaline phosphate activity in the first seven days after fracture. 1,25(OH)2D3 decreased the strength of the callus concomitant with a reduction in 45Ca incorporation. It is suggested that local application of 24,25(OH)2D3 into fractures may accelerate healing and prevent non-union.

Vitamin D metabolite levels were measured in serum and bone samples obtained from 27 patients undergoing elective bony procedures and from 28 patients operated on after a fracture. Serum 25 hydroxyvitamin D3 (25-OH-D3) and 24,25-dihydroxyvitamin D3 (24,25(OH)2D3) did not differ significantly between the elective and fracture patients, but serum 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) was significantly reduced in the fracture patients. Very little 25-OH-D3 was found in bone, although it was the major vitamin D metabolite in serum (90%). In elective patients bone levels of 24,25(OH)2D3 and 1,25(OH)2D3 were similar to those in serum; however, in bone from around pertrochanteric fractures, but not from subcapital or patellar fractures, the concentrations of these compounds were considerably increased. These findings may shed light on the mechanism of callus formation and on the role of vitamin D metabolites in bone healing.

The levels of the active metabolites of vitamin D were measured in the callus and in the epiphyseal growth plate of chicks given radioactive cholecalciferol during fracture healing. Those levels were correlated with the histological findings. Three groups of chicks were studied: a control group with no fracture, chicks with fractures fixed by Kirschner wire, and chicks with unfixed fractures. A significant increase in the levels of the active metabolites was found in the callus during the first few days after fracture. The levels of 25-hydroxycholecalciferol [25(OH)D3] and of 24,25-dihydroxycholecalciferol [24,25(OH)2D3] were higher when there was no fixation, while those of 1,25-dihydroxycholecalciferol [1,25(OH)2D3] were higher after fixation. The concentrations of these metabolites in the proximal epiphysis of the tibia were similar to those found in the callus. Based on these findings it is suggested that the active metabolites of vitamin D are directly involved in the process of fracture repair.

The release of prostaglandins E and F from the tibiae of rabbits and the surrounding muscle in vitro after fracture and pinning, or pinning alone, has been compared to the release from unoperated tissues. The fractured tibiae released significantly more prostaglandins E and F than the control tibiae three to 14 days after operation. The pinned tibiae also released more of the two prostaglandins, although this was significant only after 14 days. Consequently it was only around the third day that the fractured tibiae released significantly more prostaglandin E than the tibiae which had been pinned, but not fractured. Similar results were obtained for the release from the muscles surrounding the tibiae. Prostaglandins are important mediators of inflammation as well as potent stimulators of bone resorption. Their increased formation in response to fracture and pinning may stimulate the vascular changes, bone resorption and the proliferation of osteogenic cells observed after trauma to bone.

Osteomyelitis was induced in the tibiae of rabbits by injecting a suspension of Staphylococcus aureus and sodium tetradecylsulphate, a sclerosing agent. These rabbits were then divided into two groups: one group remained untreated and the other was fed a diet containing sodium salicylate. Two and four weeks after induction of osteomyelitis the tibiae taken from untreated rabbits with osteomyelitis and incubated in vitro released significantly more prostaglandin E and F than the control uninjected or uninfected tibiae. Tibiae taken from rabbits treated with sodium salicylate showed minimal radiographic changes and a significantly decreased release of prostaglandin E and F compared to the untreated rabbits. Prostaglandins are known to be potent bone resorbing agents and the results of this study suggest that they may also be involved in the destruction of bone which is characteristic of osteomyelitis. The treatment of rabbits with osteomyelitis using anti-inflammatory drugs, which block synthesis of prostaglandins, in addition to antibiotics, may prevent the destruction of bone and possible sequestration thereby decreasing the risk of chronic disease.