Hand osteoid osteoma: evaluation of diagnosis and treatment

Abstract

Background: OO (osteoid osteoma) is a common, osteoblastic, benign bone tumor but rarely seen in the hand region. There is still some debate about the diagnosis and treatment of hand OOs. In the present study, we aimed to evaluate the epidemiology, radiologic features, surgical treatment options and functional outcomes.

Methods: Between January 2003 and December 2014, surgically treated and pathologically verifed 9 hand OO cases were investigated retrospectively. The preoperative and postoperative clinical outcome scores were calculated using the M2-DASH (Manchester-Modifed Disabilities of Arm Shoulder and Hand) Score.

Results: Lesion locations were as follows: middle phalanx in 2/9 (22%) patients (2nd and 4th digit), proximal phalanx in 6/9 (67%) patients (one 4th, two 2nd and three 5th digits) and metacarpal (2nd) in 1/9 (11%) patient. Incidence of nidus formation was 6/9 (67%) on X-ray, 7/9 (78%) on CT imaging and 2/9 (22%) on MR imaging. The mean time to diagnosis was 13.22±5.44 months. Preoperative mean M2-DASH score was 41±6 and postoperative was 7.4±8.6.

Conclusion: Osteoid osteoma is usually seen below 25 years, and rarely found over 40 years of age. There is male dominance with a male to female ratio of 3:1. Delay of diagnosis may be encountered because of many diferential diagnoses. When OO is suspected, CT imaging should be taken before the MR imaging. Because of superiority in soft tissue imaging, MR imaging should be an alternative tool in complex cases.

Keywords: Hand, Metacarpal, Osteoid, Osteoma, Phalangea

Background

Osteoid osteoma (OO) is a vascularized, osteogenic, benign bone tumor and was frst defned by Heine in 1927 [1] and frst described by Jafe in 1935 [2]. Te lesion is characterized as a well-defned lytic area with the vas[1]cularized central nidus which is surrounded by sclero[1]sis and cortical thickening in X-ray and computerized tomography (CT) imaging. Magnetic resonance (MR) imaging usually shows an extensive bone marrow and/ or soft tissue edema [3–5]. OO is rarely seen in the hand region. Delay of diagnosis can be experienced, because of diferent clinical, radiological and histological features from the long bone OOs [6, 7]. Further, diferential diag[1]nosis and nonspecifc fndings on radiographs complicate the diagnosis. Most of the papers are case reports, but still, there is a need for case series due to the rarity and difculties in diagnosing. In the present study, we aimed to evaluate the epidemiology, radiologic features, surgical treatment options and functional outcomes

Methods

Te study was performed in accordance with the ethical standards of the Declaration of Helsinki. All patients provided informed consent before inclusion in the study, and a local ethics committee approved the study protocol. Tis study was performed on sur[1]gically treated 9 hand OO patients from January 2003 to December 2014. Inclusion criteria were histologi[1]cally verifed metacarpal and phalangeal OO. Patients who had previous percutaneous or surgical treatment and patients with recurrence were excluded from the study. All patients were evaluated regarding swell[1]ing, pain, trauma history, night pain, response to pain relievers, duration of complaints and time to diagnosis. All patients were evaluated with X-ray, CT, MR and SPECT-CT imaging preoperatively. Te preoperative and postoperative clinical outcome scores were cal[1]culated using the M2-DASH (Manchester-Modifed Disabilities of Arm Shoulder and Hand) Score [8]. Sta[1]tistical analysis was performed using SPSS software (IBM, Armonk, NY) using an unpaired Student’s t test and the Fisher exact test. Statistical signifcance level was set at p ≤ .05.

Results

Seven (78%) of patients were male, and 2 (22%) were female, and the mean age was 29±7 years. Lesion loca[1]tions were as follows: proximal phalanx in 6/9 (67%

patients (one 4th, two 2nd and three 5th digits), middle phalanx in 2/9 (22%) patients (2nd and fourth digit), and metacarpal (2nd) in 1/9 (11%) patient. Te mean time to diagnosis was 13.22±5.44  months. Tere were night pain, localized swelling, tenderness and response to pain relievers in all patients. Also, there were slight erythema[1]tous changes and local skin temperature increase in 3/9 (33%) patients. Complete blood count, erythrocyte sedi[1]mentation rate and C-reactive protein (CRP) levels were normal in all patients. Incidence of nidus formation was 6/9 (67%) on X-ray, 7/9 (78%) on CT imaging and 2/9 (22%) on MR imaging. Cortical thickening rate was 7/9 (78%) on X-ray, 7/9 (78%) on CT imaging and 3/9 (33%) on MR imaging. Non-specifc fndings were found in 2/9 (22%) cases both on X-ray and CT imaging. Bone and/ or soft tissue edema rate was 8/9 (89%) on MR imaging (Table 1). All except one were treated by unroofng and curettage using “Burr-down” method. En bloc resection was performed in one case (11%). Mean M2-DASH score was 41±6 and improved to 7.4±8.6 postoperatively. Complications were seen in 4/9 (44%) patients. During a mean of 43.44±16.58 months of follow-up, case num[1]ber 1 required a second intervention because of residual tumor, after 6  months from the curettage (Fig.  1). Tis residual tumor was treated successfully with radiofre[1]quency treatment. Despite the rehabilitation protocol, 30° proximal interphalangeal joint fexion persisted in this patient. Case 2 has encountered a superfcial infec[1]tion which was treated with oral antibiotics. In cases 7 and 9, temporary superfcial wound problems were

encountered, which did not require treatment. No other complication was encountered (Table 2)

Discussion

Tis study aimed to evaluate the epidemiology, radio[1]logic features, surgical treatment options and functional outcomes. Male:female ratio was 3:1 in our series. Gen[1]der ratio in this present study adds a diferent ratio to the literature. But this diferent data may be related to small patient numbers. Variable male:female ratios were reported, but similarly with this present study there is a signifcant male predominance in literature [6, 9–11]. In our series, mean age was in the third decade. In the literature, OOs are usually seen below the fourth decade, reported in the second or third decade, and most patients are<25 years old [9]. Phalanges were the most commonly afected bone and the most common involvement was in proximal pha[1]langes. In addition, metacarpal bone settlement was the most rare one in our study, with a rate of 1/9 (11%). Te most frequent location for OO in the hand region seems like proximal phalanges. Ozdemir et  al. reported settle[1]ment as 11 (60%) proximal and 4 (20%) middle phalan[1]ges in 18 cases [11]. Jafari et al. reported settlement as 10 (40%) proximal, 5 (20%) distal phalanges and only 4/25 (16%) metacarpal in 25 cases [9]. Incidence of nidus formation was 6/9 (67%) on X-ray and mean time to diagnosis was 13.22±5.44 months in this study. Similarly, Jafari et  al. concluded that only 13 patients (52%) had the characteristic appearances of oste[1]oid osteoma on X-ray, and they reported that the average time from the onset of symptom to successful treatment was 16.3±11.1 months [9]. On X-rays, nidus formation may not be seen or may need to pass a long time to form [12]. Marcuzzi et  al. reported that nidus incidence was 2/18 (11%) on X-ray. Tey concluded that the initial radi[1]ographs of almost all of the patients were normal. Also, they reported that the classical appearance of the dis[1]ease can only be observed between 6 and 25 months. If the nidus has enough time to mature, it could be seen on X-ray [6]. However, we could not fnd additional informa[1]tion about their mean time to diagnosis. Te duration of maturation and its pathogenesis are still unknown. Tus, initial X-ray examinations are often normal. Tis fact may be related to transposition, lack of periosteal reac[1]tion or cortical thickening. In the majority of our cases, nidus was detected on direct radiographs, but surely both planes should be taken. Typical appearance of nidus was mostly on anteroposterior and in lateral views only cor[1]tical thickening was noted. Also, normal scintigraphic fndings may have been due to low metabolic activity in a mature osteoid osteoma [6]. Hand OO patients may be treated conservatively for extended periods. A large number of diferentiating dis[1]eases directs the surgeon to shoot MR imaging instead of CT imaging. Te diagnostic rate of CT imaging was high in our series. In CT imaging, cortical thickening obscured the nidus in only one patient. On the contrary, sclerosis may range from mild-cancellous to extensive-periosteal, and may obscure the nidus [13]. Tis result may be due to our use of thin section CT imaging in our cases. As a result, CT imaging reported as superior to X-ray and MR imaging in diagnosis, surgical planning and follow-up [9]. In MR imaging, nidus was detected in only 2 cases. Te remaining cases had bone and/or soft tissue edema which obscured the nidus. MR imaging may depict the nidus and sclerosis because of adjacent bone marrow and soft tissue edema [14, 15]. Bone and/or soft tissue edema was seen on MR imaging, in all patients except one. Moreover, bone marrow and soft-tissue edema, joint efusion, and synovitis are better appreciated at MR imaging than at CT imaging [16]. Difuse bone and/ or soft tissue edema observed on MR imaging [17] may shift the diagnosis and long-term immobilization may be  

suggested. In our case series mean diagnostic time was similar to Jordan et al.’s systematic review [17]. Te long[1]est time to diagnose was 2 years due to nonspecifc fnd[1]ings in X-ray and CT imaging. Te reason for the delay was generalized edema due to pregnancy that hides the isolated fnger edema. After the regression of postpartum edema, isolated fnger swelling got attention. It should be noted that the prolongation of the treatment period causes social, economic, and psychological damage [18]. Pain was the most common symptom and all of our patients experienced night pain. In all patients, the pain was partially relieved with painkillers. In literature, the most common symptom is pain in hand OO [6, 9]. Pain severity increases at night and responds to prostaglandin inhibitors [19, 20]. Jafari et al. reported night pain rate as 21/25 (84%) and partial pain relief rate as 17/25 (68%); Marcuzzi et al. reported partial pain relief as 8/18 (44%) [6, 9]. Tus, our results regarding the night pain and pain relief are not compatible with the literature, and this shows that larger series are needed. Te second common symptom has been reported as swelling [6, 9]. Swelling may be related to the rich vascular supply or perme[1]ability, results from the prostaglandins [21]. If OO settles near the joint, swelling and erythema misdirect the sur[1]geon to a diagnosis of arthritis. Many surgical techniques like en bloc resection, corti[1]cal peeling or burr-down with curettage, percutaneous curettage and alcoholization, laser coagulation, ther[1]moregulation or radiofrequency ablation were defned [22–24]. En bloc resection requires bone grafting, and hand region is narrow for the percutaneous techniques [24, 25]. Cortical peeling is technically more difcult, especially with thick sclerosis, stripping of the cortex may not always be provided. Finding a cherry-red spot without disruption of typical appearance is possible with high-speed rolling burr. We performed the burr-down technique with curettage for all patients, except one. In one patient, 6 months after, a residual lesion was encoun[1]tered which was treated successfully with radiofrequency. Because of a narrow surgical feld, en bloc resection was performed only in one patient. We suggest burr-down method with high-speed burr and because of the low recurrence rate, grafts are not needed. To the best of our knowledge, the most recent and most extensive series is from the year 2013 with a num[1]ber of 25 cases [9]. Remaining papers are the mostly small number of case series or case reports. Te rarity of hand OOs limits to report larger series. Retrospec[1]tive, non-comparative manner and number of cases are the limitations, but the rarity obstructs the condi[1]tions for reporting a more extensive, prospective rand[1]omized-controlled series. Tere is still a need for more series to build more extensive reviews and evidence[1]based medicine.

Conclusion

Osteoid osteoma usually seen below 25  years old, and rarely found over 40  years of age. Tere is male domi[1]nance with a male to female ratio of 3:1. Delay of diag[1]nosis may be encountered because of many diferential diagnoses. Local and sole presence of non-traumatic, prolonged swelling, pain responding to painkillers, ten[1]derness, erythema, and sclerosis which is consistent with pain should remind the OO. When OO is suspected, CT imaging should be taken before the MR imaging. It should be kept in mind that the diagnostic value of thin[1]section CT imaging is higher than MR imaging. Because of superiority in soft tissue imaging, MR imaging should be an alternative tool in complex cases. Unroofng and curettage with “Burr-down” method seems to be efective in preventing residual tumors or relapses.

Authors’ contributions
 
OE: conception or design of the work, data collection and data analysis with interpretation. VG: drafting the article, critical revision of the article and fnal approval of the version to be published. Both authors read and approved the fnal manuscript
 
Author details
 
Department of Orthopaedics, Haydarpasa Numune Training and Research Hospital, Health Sciences University, Tibbiye Cd No: 40 Uskudar, Istanbul, Turkey. 2 Department of Orthopaedics, Faculty of Medicine, Bezmialem Vakif University, Vatan Cd, Fatih, 34093 Istanbul, Turkey.
 
Acknowledgements
 
None.
 
The paper was presented as a poster/oral presentation at XVth National Congress of the Hand and Upper Extremity Surgery and 4th National Congress of the Hand Rehabilitation. May 11–15, 2016, Fethiye, Turkey.
 
Competing interests
 
The authors declare that they have no competing interests
 
Availability of data and materials
 
The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request
 
Consent for publication
 
Local consent was obtained for retrospective studies, and informed consent was taken from all patients participating in the study.
 
Ethics approval and consent to participate
 
All patients stated that full permission for the publication, reproduction, broadcast and other use of photographs, recordings, and other audio-visual material.