Fracture risk after intralesional curettage of atypical cartilaginous tumors.

INTRODUCTION: The need for curettage of atypical cartilaginous tumors (ACT) is under debate. Curretage results in defects that weaken the bone potentially leading to fractures. The purpose of this study was to retrospectively determine postoperative fracture risk after curettage of chondroid tumors, including patient-specific characteristics that could influence fracture risk. METHODS: A total of 297 adult patients who underwent curettage of an ACT followed by phenolisation and augmentation were retrospectively evaluated. Explanatory variables were, sex, age, tumor size, location, augmentation type, and plate fixation. The presence of a postoperative fracture was radiologically diagnosed. Included patients had at least 90 days of follow-up. RESULTS: A total of 183 females (62%) were included and 114 males (38%), with an overall median follow-up of 3.2 years (IQR 1.6-5.2). Mean diameter of the lesions was 4.5 (SD 2.8) cm. Patients received augmentation with allograft bone (n = 259, 87%), PMMA (n = 11, 3.7%), or did not receive augmentation (n = 27, 9.1%). Overall fracture risk was 6%. Male sex (p = 0.021) and lesion size larger than 3.8 cm (p < 0.010) were risk factors for postoperative fracture. INTERPRETATION: Curettage of ACT results in an overall fracture risk of 6%, which is increased for males with larger lesions.

Prospective study for establishing minimal clinically important differences in patients with surgery for lower extremity metastases.

BACKGROUND: The clinical relevance of patient-reported outcomes score changes is often unclear. Especially in patients undergoing surgery due to lower extremity metastases - where surgery is performed in the palliative setting and the goal is to optimize functional mobility, relieve pain and improve overall quality of life. This study assessed the minimal clinically important difference (MCID) of Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Interference, Cancer-specific Physical Function, and Global (Physical and Mental Health) in patients treated surgically for impending or completed pathologic fractures. METHODS: Patients undergoing surgery for osseous metastasis of the lower extremity because of an impending or completed pathologic fracture were consecutively enrolled in this tertiary center study. Patients completed the three PROMIS questionnaires preoperatively (n = 56) and at postoperative follow-up (n = 33) assessment one to three months later. Of the 23 patients that did not complete the postoperative survey, 5 patients died within 1-3 months and 18 patients were alive at 3-months but did not respond or show up at their postoperative consult. Thirty-one patients (94%) of the 33 included patients reported at least minimal improvement and two patients (6.1%) no change 1-3 months after the surgery based on an anchor-based approach. RESULTS: The PROMIS MCIDs (95% confidence interval) for Pain Interference was 7.5 (3.4-12), Physical Function 4.1 (0.6-7.6), Global Physical Health 4.2 (2.0-6.6), and Global Mental Health 0.8 (-4.5-2.9). CONCLUSION: This prospective study successfully defined a MCID for PROMIS Pain Interference of 7.5 (3.4-12), PROMIS Physical Function of 4.1 (0.6-7.6), and Global Physical Health of 4.2 (2.0-6.6) in patients with (impending) pathological fractures due to osseous metastases in the lower extremity; no MCID could be established for PROMIS Global Mental Health. Defining a narrower MCID value for each subpopulation requires a large, prospective, multicenter study. Nevertheless, the provided MCID values allow guidance to clinicians to evaluate the impact of surgical treatment on a patient's QoL. LEVEL OF EVIDENCE: Level II Diagnostic study.

Multiflora and Gram-Negative Microorganisms Predominate in Infections Affecting Pelvic Endoprostheses Following Tumor Resection.

BACKGROUND: Periprosthetic infections after pelvic reconstruction are common, with reported rates ranging from 11% to 53%. Management of these infections is troublesome, as they commonly necessitate multiple surgical interventions and implant removal. The epidemiology and outcomes of these infections are largely unknown. The aim of this study was to analyze the causative microorganisms and the clinical outcome of treatment in a series of patients with pelvic endoprostheses affected by infection following tumor resection. METHODS: In this retrospective, multicenter cohort study, we identified all patients who developed an infection after endoprosthetic reconstruction in periacetabular tumor resection, between 2003 and 2017. The microorganisms that were isolated during the first debridement were recorded, as were the number of reoperations for ongoing infection, the antimicrobial treatment strategy, and the outcome of treatment. RESULTS: In a series of 70 patients who underwent pelvic endoprosthetic reconstruction, 18 (26%) developed an infection. The type of pelvic resection according to the Enneking-Dunham classification was type P2-3 in 14 (78%) of these patients and type P2 in 4 (22%). Median follow-up was 66 months. Fourteen (78%) of the 18 patients with infection had a polymicrobial infection. Enterobacteriaceae were identified on culture for 12 (67%). Of a total 42 times that a microorganism was isolated, the identified pathogen was gram-negative in 26 instances (62%). Microorganisms associated with intestinal flora were identified 32 times (76%). At the time of latest follow-up, 9 (50%) of the patients had the original implant in situ. Of these, 2 had a fistula and another 2 were receiving suppressive antibiotic therapy. In the remaining 9 (50%) of the patients, the original implant had been removed. At the time of final follow-up, 3 of these had a second implant in situ. The remaining 6 patients had undergone no secondary reconstruction. CONCLUSIONS: Infections that affect pelvic endoprostheses are predominantly polymicrobial and caused by gram-negative microorganisms, and may be associated with intestinal flora. This differs fundamentally from mono-bacterial gram-positive causes of conventional periprosthetic joint infections and may indicate a different pathogenesis. Our results suggest that prophylaxis and empiric treatment may need to be re-evaluated. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Complications and reoperations after surgery for 647 patients with spine metastatic disease.

BACKGROUND CONTEXT: Postoperative morbidity may offset the potential benefits of surgical treatment for spine metastatic disease; hence, risk factors for postoperative complications and reoperations should be taken into considerations during surgical decision-making. In addition, it remains unknown whether complications and reoperations shorten these patients' survival. PURPOSE: We aimed to describe and identify factors associated with having a complication within 30 days of index surgery as well as factors associated with having a subsequent reoperation. Furthermore, we assessed the effect of 30-day complications and reoperations on the patients' postoperative survival, as well as described neurologic changes after surgery. STUDY DESIGN: Retrospective cohort study. PATIENT SAMPLE: We included 647 patients 18 years and older who had surgery for metastatic disease in the spine between January 2002 and January 2014 in one of two affiliated tertiary care centers. OUTCOME MEASURES: Our primary outcomes were complications within 30 days after surgery and reoperations until final follow-up or death. METHODS: We used multivariate logistic regression to identify risk factors for 30-day complications and reoperations. We used the Cox regression analysis to assess the effect of postoperative complications and reoperations on survival. RESULTS: From 647 included patients, 205 (32%) had a complication within 30 days. The following variables were independently associated with 30-day complications: lower albumin levels (odds ratio [OR]: 0.69, 95% confidence interval [CI]=0.49-0.96, p=.021), additional comorbidities (OR=1.42, 95% CI=1.00-2.01, p=.048), pathologic fracture (OR=1.41, 95% CI=0.97-2.05, p=.031), three or more spine levels operated upon (OR=1.64, 95% CI=1.02-2.64, p=.027), and combined surgical approach (OR=2.44, 95% CI=1.06-5.60, p=.036). One hundred and fifteen patients (18%) had at least one reoperation after the initial surgery; prior radiotherapy (OR=1.56, 95% CI=1.07-2.29, p=.021) to the spinal tumor was independently associated with reoperation. 30-day complications were associated with worse survival (hazard ratio [HR]=1.40, 95% CI=1.17-1.68, p<.001), and reoperation was not significantly associated with worse survival (HR=0.80, 95% CI=0.09-1.00, p=.054). Neurologic status worsened in 42 (6.7%), remained stable in 445 (71%), and improved in 140 (22%) patients after surgery. CONCLUSIONS: Three or more spine levels operated upon and prior radiotherapy should prompt consideration of a preoperative plastic surgery consultation regarding soft tissue coverage. Furthermore, if time allows, aggressive nutritional supplementation should be considered for patient with low preoperative serum albumin levels. Surgeons should be aware of the increase in complications in patients presenting with pathologic fracture, undergoing a combined approach, and with any additional preoperative comorbidities. Importantly, 30-day complications were associated with worsened survival.

Management of metastatic humeral fractures: Variations according to orthopedic subspecialty, tumor characteristics.

HYPOTHESIS: This study assessed, if there was a difference in surgical decision making for metastatic humeral lesions based on; orthopaedic subspecialty, tumor characteristics. STUDY TYPE: Cross sectional survey study. MATERIALS AND METHODS: Twenty-four case scenarios were created by combining: tumor type, life expectancy, fracture type, and anatomical location. Participants were asked for every case: what treatment would you recommend? Participants were 78 (48%) orthopaedic oncologists and 83 (52%) orthopaedic surgeons that were not regularly involved in the treatment of bone tumors. RESULTS: There was a difference between orthopaedic oncologists and other subspecialty surgeons in recommendation for specific treatments: intramedullary nailing was less often recommended by orthopaedic oncologists (53%, 95%CI: 47-59) compared to other surgeons (62%, 95%CI: 57-67) (p=0.023); while endoprosthetic reconstruction (orthopaedic oncologists: 8.8% [95%CI: 6.6-11], other surgeons: 3.6%[95%CI: 2.3-4.8], p<0.001) and plate-screw fixation (orthopaedic oncologists: 19%[95%CI: 14-25], other surgeons: 9.5%[95%CI: 5.9-13], p=0.003) were more often recommended by orthopaedic oncologists. There was no difference in recommendation for nonoperative management. There were differences in recommendation for specific treatments based on tumor type, life expectancy, and anatomical location, but not fracture type. DISCUSSION: Subspecialty training and patient and tumor characteristics influence the decision for operative management and the decision for a specific implant in metastatic humeral fractures. LEVEL OF EVIDENCE: Level 3.

Quality of life after bone sarcoma surgery around the knee: A long-term follow-up study.

It remains unclear if quality of life (QoL) improvements could be expected in young patients after malignant bone tumour surgery after 2 years. To assess the course of QoL over time during a long-term follow-up, malignant bone tumour survivors of a previous short-term study were included. Assessments were done at least 5 years after surgery. QoL was measured with Short-form (SF)-36, TNO-AZL Questionnaire for Adult's Quality of Life (TAAQOL) and Bone tumour (Bt)-DUX. QoL throughout the follow-up was analysed by linear mixed model analysis. From the original cohort of 44 patients; 20 patients were included for this study, 10 males; mean age at surgery 15.1 years and mean follow-up 7.2 years. Twenty-one patients of the initial cohort (47%) deceased. Fifteen patients (75%) underwent limb-salvage and five (25%) ablative surgery. QoL improved significantly during follow-up at Physical Component Summary Scale scale of the SF-36 and TAAQOL and all subscales of the Bt-DUX (p < .01). No significant differences were found between current evaluations and previous evaluations at 2 years after surgery (p = .41-.98). Significant advantages after limb-salvage were seen at the PCS scale of the SF-36 (MD 13.7, p = .05) and the cosmetic scale of the Bt-DUX (MD 17.7, p = .04).

What Factors are Associated With Quality Of Life, Pain Interference, Anxiety, and Depression in Patients With Metastatic Bone Disease?

BACKGROUND: It would be helpful for the decision-making process of patients with metastatic bone disease to understand which patients are at risk for worse quality of life (QOL), pain, anxiety, and depression. Normative data, and where these stand compared with general population scores, can be useful to compare and interpret results of similar patients or patient groups, but to our knowledge, there are no such robust data. QUESTIONS/PURPOSES: We wished (1) to assess what factors are independently associated with QOL, pain interference, anxiety, and depression in patients with metastatic bone disease, and (2) to compare these outcomes with general US population values. METHODS: Between November 2011 and February 2015, 859 patients with metastatic bone disease presented to our orthopaedic oncology clinic; 202 (24%) were included as they completed the EuroQOL-5 Dimension (EQ-5DTM), PROMIS® Pain Interference, PROMIS® Anxiety, and PROMIS® Depression questionnaires as part of a quality improvement program. We did not record reasons for not responding and found no differences between survey respondents and nonrespondents in terms of age (63 versus 64 years; p = 0.916), gender (51% men versus 47% men; p = 0.228), and race (91% white versus 88% white; p = 0.306), but survey responders were more likely to be married or living with a partner (72%, versus 62%; p = 0.001). We assessed risk factors for QOL, pain interference, anxiety, and depression using multivariable linear regression analysis. We used the one-sample signed rank test to assess whether scores differed from US population averages drawn from earlier large epidemiologic studies. RESULTS: Younger age (ß regression coefficient [ß], < 0.01; 95% CI, 0.00-0.01; p = 0.041), smoking (ß, -0.12; 95% CI, -0.22 to -0.01; p = 0.026), pathologic fracture (ß, -0.10; 95% CI, -0.18 to -0.02; p = 0.012), and being unemployed (ß, -0.09; 95% CI, -0.17 to -0.02; p = 0.017) were associated with worse QOL. Current smoking status was associated with more pain interference (ß, 6.0; 95% CI, 1.6-11; p = 0.008). Poor-prognosis cancers (ß, 3.8; 95% CI, 0.37-7.2; p = 0.030), and pathologic fracture (ß, 6.3; 95% CI, 2.5-7.2; p = 0.001) were associated with more anxiety. Being single (ß, 5.9; 95% CI, 0.83-11; p = 0.023), and pathologic fracture (ß, 4.4; 95% CI, 0.8-8.0; p = 0.017) were associated with depression. QOL scores (0.68 versus 0.85; p < 0.001), pain interference scores (65 versus 50; p < 0.001), and anxiety scores (53 versus 50; p = 0.011) were worse for patients with bone metastases compared with general US population values, whereas depression scores were comparable (48 versus 50; p = 0.171). CONCLUSIONS: Impending pathologic fractures should be treated promptly to prevent deterioration in QOL, anxiety, and depression. Our normative data can be used to compare and interpret results of similar patients or patient groups. Future studies could focus on specific cancers metastasizing to the bone, to further understand which patients are at risk for worse patient-reported outcomes. LEVEL OF EVIDENCE: Level III, prognostic study.

The vascularised fibular graft for limb salvage after bone tumour surgery: a multicentre study.

Vascularised fibular grafts (VFGs ) are a valuable surgical technique in limb salvage after resection of a tumour. The primary objective of this multicentre study was to assess the risk factors for failure and complications for using a VFG after resection of a tumour. The study involved 74 consecutive patients (45 men and 29 women with mean age of 23 years (1 to 64) from four tertiary centres for orthopaedic oncology who underwent reconstruction using a VFG after resection of a tumour between 1996 and 2011. There were 52 primary and 22 secondary reconstructions. The mean follow-up was 77 months (10 to 195). In all, 69 patients (93%) had successful limb salvage; all of these united and 65 (88%) showed hypertrophy of the graft. The mean time to union differed between those involving the upper (28 weeks; 12 to 96) and lower limbs (44 weeks; 12 to 250). Fracture occurred in 11 (15%), and nonunion in 14 (19%) patients. In 35 patients (47%) at least one complication arose, with a greater proportion in lower limb reconstructions, non-bridging osteosynthesis, and in children. These complications resulted in revision surgery in 26 patients (35%). VFG is a successful and durable technique for reconstruction of a defect in bone after resection of a tumour, but is accompanied by a significant risk of complications, that often require revision surgery. Union was not markedly influenced by the need for chemo- or radiotherapy, but should not be expected during chemotherapy. Therefore, restricted weight-bearing within this period is advocated.

Hemicortical resection and inlay allograft reconstruction for primary bone tumors: a retrospective evaluation in the Netherlands and review of the literature.

BACKGROUND: Selected primary tumors of the long bones can be adequately treated with hemicortical resection, allowing for optimal function without compromising the oncological outcome. Allografts can be used to reconstruct the defect. As there is a lack of studies of larger populations with sufficient follow-up, little is known about the outcomes of these procedures. METHODS: In this nationwide retrospective study, all patients treated with hemicortical resection and allograft reconstruction for a primary bone tumor from 1989 to 2012 were evaluated for (1) mechanical complications and infection, (2) oncological outcome, and (3) failure or allograft survival. The minimum duration of follow-up was twenty-four months. RESULTS: The study included 111 patients with a median age of twenty-eight years (range, seven to seventy-three years). The predominant diagnoses were adamantinoma (n = 37; 33%) and parosteal osteosarcoma (n = 18; 16%). At the time of review, 104 patients (94%) were alive (median duration of follow-up, 6.7 years). Seven patients (6%) died, after a median of twenty-six months. Thirty-seven patients (33%) had non-oncological complications, with host bone fracture being the most common (n = 20, 18%); all healed uneventfully. Other complications included nonunion (n = 8; 7%), infection (n = 8; 7%), and allograft fracture (n = 3; 3%). Of ninety-seven patients with a malignant tumor, fifteen (15%) had residual or recurrent tumor and six (6%) had metastasis. The risk of complications and fractures increased with the extent of cortical resection. CONCLUSIONS: Survival of hemicortical allografts is excellent. Host bone fracture is the predominant complication; however, none of these fractures necessitated allograft removal in our series. The extent of resection is the most important risk factor for complications. Hemicortical resection is not recommended for high-grade lesions; however, it may be superior to segmental resection for treatment of carefully selected tumors, provided that it is possible to obtain adequate margins. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Nonbacterial osteitis of the clavicle: longitudinal imaging series from initial diagnosis to clinical improvement.

Nonbacterial osteitis is a rare autoinflammatory disease. Often it is mistaken for a tumor or osteomyelitis. We present a case of a twelve-year-old girl referred to our hospital because of a lesion of the right clavicle. The differential diagnoses were sarcoma, osteitis, and Langerhans cell histiocytosis. After biopsy the diagnosis nonbacterial osteitis (NBO) was established. Treatment of choice is a nonsteroidal anti-inflammatory drug. This case report gives a complete follow-up of the disease, showing the pitfalls of the diagnosis.

Clinical outcome of pedestal cup endoprosthetic reconstruction after resection of a peri-acetabular tumour.

Peri-acetabular tumour resections and their subsequent reconstruction are among the most challenging procedures in orthopaedic oncology. Despite the fact that a number of different pelvic endoprostheses have been introduced, rates of complication remain high and long-term results are mostly lacking. In this retrospective study, we aimed to evaluate the outcome of reconstructing a peri-acetabular defect with a pedestal cup endoprosthesis after a type 2 or type 2/3 internal hemipelvectomy. A total of 19 patients (11M:8F) with a mean age of 48 years (14 to 72) were included, most of whom had been treated for a primary bone tumour (n = 16) between 2003 and 2009. After a mean follow-up of 39 months (28 days to 8.7 years) seven patients had died. After a mean follow-up of 7.9 years (4.3 to 10.5), 12 patients were alive, of whom 11 were disease-free. Complications occurred in 15 patients. Three had recurrent dislocations and three experienced aseptic loosening. There were no mechanical failures. Infection occurred in nine patients, six of whom required removal of the prosthesis. Two patients underwent hindquarter amputation for local recurrence. The implant survival rate at five years was 50% for all reasons, and 61% for non-oncological reasons. The mean Musculoskeletal Tumor Society score at final follow-up was 49% (13 to 87). Based on these poor results, we advise caution if using the pedestal cup for reconstruction of a peri-acetabular tumour resection.

Giant cell tumors of the sacrum--a nationwide study on midterm results in 26 patients after intralesional excision.

PURPOSE: Evaluation of recurrences, complications and function at mid-term follow-up after curettage for sacral giant cell tumor (GCT). METHODS: We retrospectively studied all 26 patients treated for sacral GCT in the Netherlands (from 1990 to 2010). Median follow-up was 98 (6-229) months. All patients underwent intralesional excision, 21 with local adjuvants, 5 radiotherapy, 3 IFN-α, 1 bisphosphonates. Functional outcome was assessed using Musculoskeletal Tumor Society (MSTS) score. Statistics were performed with Kaplan-Meier, Cox regression, log rank and Mann-Whitney U. RESULTS: Recurrence rate was 14/26 after median 13 (3-139) months and was highest after isolated curettage (4/5). Soft tissue masses >10 cm increased recurrence risk (HR = 3.3, 95 % CI = 0.81-13, p = 0.09). Complications were reported in 12/26 patients. MSTS was superior in patients without complications (27 vs. 21; p = 0.024). CONCLUSION: Recurrence rate for sacral GCT was highest after isolated curettage, indicating that (local) adjuvant treatment is desired to obtain immediate local control. Complications were common and impaired function.

Intercalary allograft reconstructions following resection of primary bone tumors: a nationwide multicenter study.

BACKGROUND: Favorable reports on the use of massive allografts to reconstruct intercalary defects underline their place in limb-salvage surgery. However, little is known about optimal indications as reports on failure and complication rates in larger populations remain scarce. We evaluated the incidence of and risk factors for failure and complications, time to full weight-bearing, and optimal fixation methods for intercalary allografts after tumor resection. METHODS: A retrospective study was performed in all four centers of orthopaedic oncology in the Netherlands. All consecutive patients reconstructed with intercalary (whole-circumference) allografts after tumor resection in the long bones during 1989 to 2009 were evaluated. The minimum follow-up was twenty-four months. Eighty-seven patients with a median age of seventeen years (range, 1.5 to 77.5 years) matched inclusion criteria. The most common diagnoses were osteosarcoma, Ewing sarcoma, adamantinoma, and chondrosarcoma. The median follow-up period was eighty-four months (range, twenty-five to 262 months). Ninety percent of tumors were localized in the femur or the tibia. RESULTS: Fifteen percent of our patients experienced a graft-related failure. The major complications were nonunion (40%), fracture (29%), and infection (14%). Complications occurred in 76% of patients and reoperations were necessary in 70% of patients. The median time to the latest complication was thirty-two months (range, zero to 200 months). The median time to full weight-bearing was nine months (range, one to eighty months). Fifteen grafts failed, twelve of which failed in the first four years. None of the thirty-four tibial reconstructions failed. Reconstruction site, patient age, allograft length, nail-only fixation, and non-bridging osteosynthesis were the most important risk factors for complications. Adjuvant chemotherapy and irradiation had no effects on complication rates. CONCLUSIONS: We report high complication rates and considerable failure rates for the use of intercalary allografts; complications primarily occurred in the first years after surgery, but some occurred much later after surgery. To reduce the number of failures, we recommend reconsidering the use of allografts for reconstructions of defects that are ≥15 cm, especially in older patients, and applying bridging osteosynthesis with use of plate fixation.

Prognostic factors in localized extremity osteosarcoma: a systematic review.

AIM: Finding reliable prognostic factors for osteosarcoma remains problematic. A systematic review [Davis AM, Bell RS, Goodwin PJ. Prognostic factors in osteosarcoma: a critical review. Journal of Clinical Oncology 1994; 12(2): 423-431.] showed chemotherapy response as only independent factor. We tried to identify evidence-based prognostic factors in the literature since 1992 and to establish pooled relative risks of factors. METHODS: MEDLINE and Embase search (1992-August 2006). Two reviewers independently selected papers addressing prognostic factors in localized extremity osteosarcoma, which were studied for methodological quality, and valuable new factors. An attempt was made to pool results. RESULTS: Of 1777 "hits", 93 papers were studied in depth. Several "new" prognostic factors were found. Only 7 papers were of sufficient quality to analyze. Chemotherapy response, tumor size and site, alkaline phosphatase level and p-glycoprotein expression seemed to be independent factors. Some new factors looked promising. CONCLUSIONS: Although the literature is abundant, it is disappointing that only few papers are of sufficient quality to allow hard conclusions. Because of heterogeneity of the studies pooling results is hardly possible. There is a need for standardization of studies and reports.

Do pathological fractures influence survival and local recurrence rate in bony sarcomas?

The influence of pathological fracture on surgical management, local recurrence and survival was established in patients with high grade, localised, extremity osteosarcoma (n=484), chondrosarcoma (n=130) and Ewing's sarcoma (n=156). Limb salvage was possible in 79% of patients with a fracture compared to 84% of patients without a fracture (p=0.17). No difference in local recurrence was found between fracture and control groups. In univariate analysis, survival in the fracture group was lower than in the control group for osteosarcoma (34% versus 58%, p<0.01) and chondrosarcoma (35% versus 63%, p=0.04), but not for Ewing's sarcoma (75% versus 64%, p=0.80). In multivariate analysis, fracture remained a significant predictor of survival for osteosarcoma, but not for chondrosarcoma, where dedifferentiated subtype appeared to be decisive. Pathological fracture independently predicts worse survival in osteosarcoma, but not chondrosarcoma and Ewing's sarcoma. Limb saving surgery seems safe, if adequate resection margins are achieved.

Increased external tibial torsion and osteochondritis dissecans of the knee.

In the past, osteochondritis dissecans of the knee was associated with increased tibial exotorsion, established with a clinical measuring method. Now the gold standard for determining tibial torsion is computed tomography. The aim of the current study was to establish whether the abovementioned association could be confirmed in the current patients, measured with computed tomography. Confounding aberrations of femoral torsion were ruled out. Twenty-three patients with osteochondritis dissecans in 27 knees were treated between 1991 and 1999. Symptoms and treatment results were comparable with those reported in the literature. Femoral and tibial torsion were measured with a computed tomography scan. The average femoral antetorsion was comparable with that in the literature. The average tibial exotorsion was significantly higher than the control value. Exotorsion was increased more in patients with bilateral osteochondritis, and extremely high in patients with persisting complaints. Increased tibial exotorsion could play a role in development of osteochondritis dissecans of the knee. Extreme exotorsion might be prognostic for persistent complaints.

Effect of recombinant human osteogenic protein-1 on the healing of a freshly closed diaphyseal fracture.

Osteogenic protein-1 (OP-1), or bone morphogenetic protein-7, is an osteoinductive morphogen that is involved in embryonic skeletogenesis and in bone repair. In bone defect models without spontaneous healing, local administration of recombinant human OP-1 (rhOP-1) induces complete healing. To investigate the ability of rhOP-1 to accelerate normal physiologic fracture healing, an experimental study was performed. In 40 adult female goats a closed tibial fracture was made, stabilized with an external fixator, and treated as follows: (1) no injection; (2) injection of 1 mg rhOP-1 dissolved in aqueous buffer; (3) injection of collagen matrix; and (4) injection of 1 mg rhOP-1 bound to collagen matrix. The test substances were injected in the fracture gap under fluoroscopic control. At 2 and 4 weeks, fracture healing was evaluated with radiographs, three-dimensional computed tomography (CT), dual-energy X-ray absorptiometry, biomechanical tests, and histology. At 2 weeks, callus diameter, callus volume, and bone mineral content at the fracture site were significantly increased in both rhOP-1 groups compared with the no-injection group. As signs of accelerated callus maturation, bending and torsional stiffness were higher and bony bridging of the fracture gap was observed more often in the group with rhOP-1 dissolved in aqueous buffer than in uninjected fractures. Treatment with rhOP-1 plus collagen matrix did not result in improved biomechanical properties or bony bridging of the fracture gap at 2 weeks. At 4 weeks there were no differences between groups, except for a larger callus volume in the rhOP-1 plus collagen matrix group compared with the control groups. All fractures showed an advanced stage of healing at 4 weeks. In conclusion, the healing of a closed fracture in a goat model can be accelerated by a single local administration of rhOP-1. The use of a carrier material does not seem to be crucial in this application of rhOP-1.