John P. Heiner

Distant soft tissue metastases: a series of 30 new patients and 91 cases from the literature.

Background: Thirty patients with soft-tissue metastases were reviewed retrospectively and compared with 91 cases previously reported. Soft tissue metastases were most commonly presented to the musculoskeletal oncologist as a painful mass in patients with no history of cancer. In this setting, lung carcinoma was the most frequent primary source. The purpose of this article is to report the largest single series of distant soft-tissue metastases and to compare the findings with those of the literature.Methods: Thirty consecutive patients were referred to musculoskeletal oncologists. Their cases were reviewed retrospectively for comparison with 91 cases from the clinical literature.Results: The most common clinical presentation of the soft-tissue mass was as the presenting symptom of previously undiagnosed cancer or concurrent with the primary source of cancer. A minority of cases were discovered in the setting of widespread metastases. Twenty-one new patients had carcinomas, 6 sarcomas, and 1 each multiple myeloma, lymphoma, and melanoma. Lung carcinoma was the most common primary source. The most common presenting symptom was that of a painful mass. Skeletal muscle of the thigh was the most common site. Radiological features were not specific. Soft tissue sarcoma was a common clinical misdiagnosis. Twenty-one new patients were dead of disease at a mean 5.4 months (range 1–19 months) after diagnosis of the metastasis: this percentage was similar to that reported in the literature.Conclusions: In this musculoskeletal oncology referral-based clinical series, soft tissue metastases most commonly occur in patients with a painful soft tissue mass and no history of cancer. Lung is the most frequent primary source. Treatment should be individualized according to the underlying disease and its prognosis.

Critical evaluation of Mirels' rating system for impending pathologic fractures.

This project examined the hypothesis that Mirels’ rating system for impending pathologic fractures is reproducible, valid, and applicable across various experience levels and training backgrounds. Twelve true clinical histories and corresponding radiographs for patients with femoral metastatic lesions were reviewed by 53 participants from five experience levels: orthopaedic residents, musculoskeletal radiologists, orthopaedic attendings, fellowship-trained practicing orthopaedic oncologists, and radiation or medical oncologists. Each examiner provided individual and total Mirels’ scores and independent determination of impending fracture using clinical judgment. A subset of seven histories without prophylactic fixation provided a natural history group. There was highly significant agreement across experience categories for overall Kappa and for the concordance for individual and overall scores. Kappa analysis showed good agreement for site, moderate agreement for type, and fair agreement for size and pain. There was no significant difference in overall scores across experience levels. The pooled odds ratio favored Mirels rating system over clinical judgment regardless of experience level. Overall sensitivity was 91% and specificity was 35%. Mirels’ system seems to be reproducible, valid, and more sensitive than clinical judgment across experience levels. However, although the system is a valuable screening tool, more specific parameters are needed.

Magnetic resonance imaging of muscle tears

Magnetic resonance scans were obtained on 17 patients with acute, subacute, or chronic muscle tears. These patients presented with complaints of persistent pain or a palpable mass. Magnetic resonance findings were characterized according to alterations in muscle shape and the presence of abnormal high signal within the injured muscle. These areas of high signal were noted on both T1-weighted and T2-weighted scans and were presumed to represent areas of intramuscular hemorrhage.

Histomorphometric description of allograft bone remodeling and union in a canine segmental femoral defect model: A comparison of rhBMP-2, cancellous bone graft, and absorbable collagen sponge

The purpose of this study was to determine the effect of recombinant human bone morphogenetic protein type 2 (rhBMP‐2) on the histomorphometry of femoral allograft‐host bone union and allograft remodeling. A 6 cm mid‐diaphyseal femoral defect was created and filled with an allograft stabilized with an interlocking nail in 21 dogs. Dogs were randomly divided into three equal groups and the allograft‐host bone junctions and the mid‐diaphyses of the allografts were treated with either an absorbable collagen sponge (ACS) loaded with rhBMP‐2 (BMP group), an autogenous cancellous bone graft (CBG group), or ACS loaded with buffer solution (ACS group). All dogs received daily tetracycline until sacrifice at 24 weeks to label new bone formation. Histomorphometric analyses on sections of proximal and distal allograft‐host bone junctions and the mid‐diaphyseal portion of allografts were performed using fluorescent and regular light microscopy. Analyses of the host bone and junctions between allograft and host bone revealed significantly greater new bone formation and larger osteon radii in the BMP group compared to CBG and ACS groups and contralateral intact bone. Porosity in CBG and ACS groups was significantly higher than in the BMP group, which had similar values to intact bone. In transverse sections of allografts, the largest pore diameters were present in the CBG group. Based on all parameters measured, significantly higher bone turnover occurred in the outer cortical area of the allograft in all groups as compared to the inner cortical and mid‐cortical areas. New bone formation and osteon radius/osteon width in allografts were similar for all three groups. Higher porosity and larger pore diameters in the CBG and ACS groups suggested higher bone resorption versus formation in these groups compared to the BMP group. The results of this study reveal more balanced allograft bone resorption and bone formation in the BMP group, with greater resorptive activity in the CBG and ACS groups. However, neither rhBMP‐2 nor autogenous bone graft increased allograft incorporation when compared to the negative control (ACS group).

The effect of recombinant human bone morphogenetic protein-2 on femoral reconstruction with an intercalary allograft in a dog model

This study compared the effect of augmentation of allograft–host bone junctions with recombinant human bone morphogenetic protein‐2 (rhBMP‐2) on an absorbable collagen sponge (ACS), autogenous cancellous bone graft (CBG), and a collagen sponge alone in a canine intercalary femoral defect model repaired with a frozen allograft. Outcome assessment included serial radiographs, dual energy X‐ray absorptiometry scans, and gait analyses, and mechanical testing and histology of post‐mortem specimens. The distal junction healed more quickly and completely with rhBMP‐2 than ACS alone based on qualitative radiography and histologic evaluations. The primary tissue in the unhealed gaps in the ACS group was fibrous connective tissue. The proximal allograft–host bone junction had complete bone union in the three treatment groups. There was significantly greater new bone callus formation at both junctions with rhBMP‐2 than with CBG or ACS alone that resulted in increased bone density around the allograft–host bone junctions. All dogs shifted their weight from the treated leg to the contralateral pelvic limb immediately after surgery. Weight bearing forces were redistributed equally between the pelvic limbs at 12 weeks after surgery with rhBMP‐2, at 16 weeks after surgery with CBG, and at 24 weeks after surgery with ACS alone. Bending and compressive stiffnesses of the whole treated femora were equal to the contralateral control femora in all treatment groups, whereas torsional rigidities of the whole treated femora for the CBG and ACS groups were significantly less than the control. Both the proximal and distal junctions the treated with rhBMP‐2 had torsional stiffnesses and strengths equal to intact control bones. Ultimate failure torques of the proximal junctions of the CBG group and of both junctions of the ACS group were significantly less than the BMP‐treated bones. Augmentation of the allograft–host bone junctions with rhBMP‐2 on an ACS gave results for all parameters measured that equaled or exceeded autogenous graft in this canine intercalary femoral defect model.

Adverse clinical events during cemented long-stem femoral arthroplasty.

The occurrence and risk factors for adverse clinical events associated with cemented long-stem femoral arthroplasty were studied. The hypothesis was that patients with femoral metastatic disease and previously uninstrumented canals were at higher risk for such adverse events. Fifty-five consecutive patients requiring long-stem femoral arthroplasty at two institutions were retrospectively reviewed. Adverse clinical events including hypotension, sympathomimetic administration, and O2 desaturation were subclassified according to the timing of their occurrence. Adverse events occurred in 34 of 55 patients (62%), including coma in two patients and death in a third patient. The three catastrophic events occurred in patients with metastatic disease involving previously uninstrumented femoral canals. Desaturation was more frequent in patients with metastatic disease and previously uninstrumented canals compared with patients who had revision arthroplasty and patients with previously instrumented femoral canals. Preexisting medical illness was a significant risk factor in total adverse clinical events that included cement-associated adverse clinical events and cement-associated and postoperative hypotension. In long-stem cemented femoral components risk factors for adverse clinical events included metastatic disease, uninstrumented femoral canals, and preexisting medical conditions. These findings underscore the importance of appropriate patient selection, patient and family education, and anesthesia preparation before long-stem cemented femoral arthroplasty.

Case report 803

In summary, a 36-year-old man presented with pain and limited motion in the shoulder. Clinical examination revealed obliteration of normal scapular landmarks in the conspicuous absence of any palpable soft tissue mass. Roentgenograms showed progressive osteolysis of the scapula. Biopsy confirmed the diagnosis of Gorhams disease. MRI played a key role in defining the extent of disease involvement and in displaying the distinct soft tissue anatomy. These MRI features are to our knowledge previously undescribed.

A biomechanical analysis of prophylactic fixation for pathological fractures of the distal third of the humerus.

Twenty-four matched pairs of fresh-frozen humeri from human cadavera were divided randomly into four groups, in order to determine the most biomechanically desirable construct for the prophylactic fixation of impending fractures of the distal third of the humerus. Group I comprised intact humeri and matched humeri in which a 50 per cent lateral, semicylindrical cortical defect of the distal third had been created, resulting in a reproducible model of an impending fracture due to a lytic defect involving 50 per cent cortical disruption at the distal end of the humeral medullary canal. In Group II, such a lateral defect was created in both the right and the left, matched humeri. Group III was composed of humeri in which the defect had been fixed prophylactically with a single plate and the contralateral humeri, which had been treated with double-plating. Group IV comprised specimens in which the defect had been fixed with double-plating as well as those fixed with Rush rods. The fixation of each specimen in Groups III and IV was supplemented with bone cement. Each specimen was tested in torsion to failure, and the resulting peak torque, torsional stiffness, and total energy absorbed were analyzed for each group. The Group-I specimens that had a defect had a significantly lower (p < 0.05) peak torque, torsional stiffness, and total energy absorbed than the intact specimens; all of the specimens with a defect failed at the defect, and all of the intact specimens failed proximally. In Group II, there was a high side-to-side association with respect to peak torque, torsional stiffness, and total energy absorbed.(ABSTRACT TRUNCATED AT 250 WORDS)

A Comparison of Single-Shot Adductor Canal Block vs Femoral Nerve Catheter for Total Knee Arthroplasty.

Abstract The aim of this study was to compare perioperative analgesia provided by single-injection adductor canal block (ACB) to continuous femoral nerve catheter (FNC) when used in a multimodal pain protocol for total knee arthroplasty (TKA). A retrospective cohort study compared outcome data for 148 patients receiving a single-injection ACB to 149 patients receiving an FNC. The mean length of stay (LOS) in the ACB group was 2.67 (±0.56) and 3.01 days (±0.57) in the FNC group ( P P P =0.01). Single-injection ACB offered similar pain control and earlier discharge compared to continuous FNC in patients undergoing TKA.

Alterations in femoral strain, micromotion, cortical geometry, cortical porosity, and bony ingrowth in uncemented collared and collarless prostheses in the dog

The effects of a collared femoral endoprosthesis in uncemented total hip arthroplasty were evaluated in 12 dogs. This experimental study compared the biomechanic and histologic responses between collared and collarless femoral prostheses 4 months after implantation. Implant stability (micromotion) and cortical surface strain were evaluated immediately and 4 months after implantation in a simulated postoperative condition, whereas bone ingrowth, cortical porosity, and cortical remodeling were assessed after 4 months only. There were no significant differences in implant stability or cortical surface strains when the collared and collarless groups were compared acutely or after 4 months (P > .05). There were also no significant differences in percent fill, bony ingrowth, or cortical geometry after 4 months (P > .05). There was a significant increase in cortical porosity measured from the proximal femur after 4 months for both the collared (P = .0002) and collarless groups (P = .009) and when both groups were compared (collarless, 8.2% and collared, 5.8%; P = .03). The results suggest that a collar may be beneficial in decreasing the cortical remodeling that occurs in the proximal femoral cortex after implantation of an uncemented total hip arthroplasty.